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研究者情報

マスター

アカウント（マスター）

  • 氏名

    内田　努(ウチダ　ツトム), ウチダ　ツトム

所属（マスター）

  • 工学研究院　応用物理学部門　凝縮系物理工学分野

所属（マスター）

  • 工学研究院　応用物理学部門　凝縮系物理工学分野

独自項目

syllabus

  • 2021, 生物物理工学特論, Biophysics, 修士課程, 工学院, 水分子、水素結合、氷、クラスレート、 ダイナミカルシステム、非線形ダイナミクス、カオス、フラクタル
  • 2021, 生物物理工学特論, Biophysics, 博士後期課程, 工学院, 水分子、水素結合、氷、クラスレート、 ダイナミカルシステム、非線形ダイナミクス、カオス、フラクタル
  • 2021, 応用物理学英文講読, Seminar on Advanced Physics, 学士課程, 工学部, 科学英語、工業英語、英文読解、グループ学習、プレゼンテーション
  • 2021, 応用物理学, Introduction to Applied Physics, 学士課程, 工学部, ナノテク・ナノサイエンス、光科学、量子力学、複雑ネットワーク
  • 2021, 応用物理学, Introduction to Applied Physics, 学士課程, 工学部, ナノテクノロジー、光科学、複雑ネットワーク、電子顕微鏡、太陽系外惑星
  • 2021, 一般教育演習(ﾌﾚｯｼｭﾏﾝｾﾐﾅｰ), Freshman Seminar, 学士課程, 全学教育, 超伝導、ゼロ抵抗、マイスナー効果、人工雪、結晶成長、量子通信、天文観測技術，光学実験、フェムト秒レーザー、レーザー加工 材料科学、X線回折、結晶構造、熱膨張係数、構造材料、力学特性、微細組織

researchmap

プロフィール情報

学位

  • 博士（工学）（北海道大学）

プロフィール情報

  • 姓

    内田

  • 名

    努

対象リソース

業績リスト

研究分野

  • 自然科学一般 / 生物物理、化学物理、ソフトマターの物理
  • ナノテク・材料 / ナノ材料科学
  • ナノテク・材料 / 基礎物理化学

経歴

  • 2004年03月 - 現在 北海道大学 大学院工学研究院 応用物理学部門 准教授

受賞

  • 2012年09月 （公社）日本雪氷学会 学術賞
     ガスハイドレートの生成過程とガス包接機構に関する基礎的研究 
    受賞者: 内田 努
  • 2002年10月 日本雪氷学会 2002年度平田賞
     氷の中のガスハイドレートの物性的研究 
    受賞者: 内田 努
  • 2000年02月 日本エネルギー学会 平成11年度進歩賞(学術部門)
     ガスハイドレートのラマン分光測定に関する研究 
    受賞者: 内田 努

論文

  • Tsutomu Uchida, Ren Sugibuchi, Masato Hayama, Kenji Yamazaki
    The Journal of Chemical Physics 2024年02月21日
  • Tsutomu Uchida, Yukiharu Fukushi
    Nanomaterials 2023年01月02日
  • Akio Suzuta, Kenji Yamazaki, Kazutoshi Gohara, Tsutomu Uchida
    JOURNAL OF PHYSICAL CHEMISTRY C 126 30 12780 - 12789 2022年08月 
    A trace method for determining the trajectories of single metal atoms dispersed on graphene was developed using scanning transmission electron microscopy with angstrom-order accuracy. This method was applied to platinum (Pt) and gold (Au) single atoms dispersed on free-standing single-layer graphene to observe the difference in their dynamic behaviors under electron beam irradiation. High-angle annular dark-field imaging showed that most of the atoms were present at the nanographene edge, especially in three or higher layers of nanographene, but few on the terrace of graphene. According to trajectory analysis, approximately 70% of the Pt single atoms stayed within one atomic distance of graphene (1.4 angstrom) for the whole observation period (40 s). Therefore, Pt continued to be stably dispersed on graphene as single atoms. On the other hand, more than 40% of Au single atoms traveled a distance exceeding the size of the six-membered ring of graphene (2.8 angstrom) even within the minimum observation interval (4 s). Clearly, Au was confirmed to have a larger mobility than Pt under the same electron beam irradiation conditions, which may be one reason for the difficulty in keeping the single atom state for Au.
  • Tsutomu Uchida, Ren Sugibuchi, Kenji Yamazaki, Kazutoshi Gohara
    ENERGY & FUELS 2022年07月 
    Formation and dissociation processes of gas hydrates have been studied for managing the flow of natural gas and for developing new natural gas resources. Recently, such studies have also examined the unique properties of gas hydrates for use in industry, such as gas and energy storages. However, a large degree of supercooling (or super-saturation) and a long induction time are required to form gas hydrates even when their components (water and guest gas) are in hydrate-forming conditions. To overcome these obstacles, various formation-promoting technologies have been studied. In this mini review, we summarize the technologies for promoting the nucleation process in gas hydrate formation. We then focus on recent studies on the use of ultrafine bubbles (UFBs) to exploit the memory effect, which reduces the induction time. We add new data to clarify our experimental results on the formation of single-gas hydrate under an agitated environment and show that UFBs play an important role in promoting gas hydrate formation.
  • Tsutomu Uchida, Wataru Shigeyama, Ikumi Oyabu, Kumiko Goto-Azuma, Fumio Nakazawa, Tomoyuki Homma, Kenji Kawamura, Dorthe Dahl-Jensen
    JOURNAL OF GLACIOLOGY 68 269 547 - 556 2022年06月 
    Tiny samples of ancient atmosphere in air bubbles within ice cores contain argon (Ar), which can be used to reconstruct past temperature changes. At a sufficient depth, the air bubbles are compressed by the overburden pressure under low temperature and transform into air-hydrate crystals. While the oxygen (O-2) and nitrogen (N-2) molecules have indeed been identified in the air-hydrate crystals with Raman spectroscopy, direct observational knowledge of the distribution of Ar at depth within ice sheet and its enclathration has been lacking. In this study, we applied scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) to five air-hydrate crystals in the Greenland NEEM ice core, finding them to contain Ar and N. Given that Ar cannot be detected by Raman spectroscopy, the method commonly used for O-2 and N-2, the SEM-EDS measurement method may become increasingly useful for measuring inert gases in deep ice cores.
  • 大藪幾美, 川村賢二, 川村賢二, 川村賢二, 内田努, 藤田秀二, 藤田秀二, 北村享太郎, 平林幹啓, 青木周司, 森本真司, 中澤高清, SEVERINGHAUS Jeffrey P., MORGAN Jacob
    雪氷研究大会講演要旨集(Web) 15 12 5529 - 5555 2021年12月10日 [査読有り][通常論文]
     
    Abstract. The variations of δO2/N2 and δAr/N2 in the Dome Fuji ice core were measured from 112 m (bubbly ice) to 2001 m (clathrate hydrate ice). Our method, combined with the low storage temperature of the samples (−50 ∘C), successfully excludes post-coring gas-loss fractionation signals from our data. From the bubbly ice to the middle of the bubble–clathrate transition zone (BCTZ) (112–800 m) and below the BCTZ (>1200 m), the δO2/N2 and δAr/N2 data exhibit orbital-scale variations similar to local summer insolation. The data in the lower BCTZ (800–1200 m) have large scatter, which may be caused by millimeter-scale inhomogeneity of air composition combined with finite sample lengths. The insolation signal originally recorded at the bubble close-off remains through the BCTZ, and the insolation signal may be reconstructed by analyzing long ice samples (more than 50 cm for the Dome Fuji core). In the clathrate hydrate zone, the scatter around the orbital-scale variability decreases with depth, indicating diffusive smoothing of δO2/N2 and δAr/N2. A simple gas diffusion model was used to reproduce the smoothing and thus constrain their permeation coefficients. The relationship between δAr/N2 and δO2/N2 is markedly different for the datasets representing bubble close-off (slope ∼ 0.5), bubble–clathrate hydrate transformation (∼1), and post-coring gas loss (∼0.2), suggesting that the contributions of the mass-independent and mass-dependent fractionation processes are different for those cases. The method and data presented here may be useful for improving the orbital dating of deep ice cores over the multiple glacial cycles and further studying non-insolation-driven signals (e.g., atmospheric composition) of these gases.
  • Ikumi Oyabu, Kenji Kawamura, Tsutomu Uchida, Shuji Fujita, Kyotaro Kitamura, Motohiro Hirabayashi, Shuji Aoki, Shinji Morimoto, Takakiyo Nakazawa, Jeffrey P. Severinghaus, Jacob D. Morgan
    CRYOSPHERE 15 12 5529 - 5555 2021年12月 
    The variations of delta O-2/N-2 and delta Ar/N-2 in the Dome Fuji ice core were measured from 112 m (bubbly ice) to 2001 m (clathrate hydrate ice). Our method, combined with the low storage temperature of the samples (-50 degrees C), successfully excludes post-coring gas-loss fractionation signals from our data. From the bubbly ice to the middle of the bubble-clathrate transition zone (BCTZ) (112-800m) and below the BCTZ (> 1200 m), the delta O-2/N-2 and delta Ar/N-2 data exhibit orbital-scale variations similar to local summer insolation. The data in the lower BCTZ (800-1200 m) have large scatter, which may be caused by millimeter-scale inhomogeneity of air composition combined with finite sample lengths. The insolation signal originally recorded at the bubble close-off remains through the BCTZ, and the insolation signal may be reconstructed by analyzing long ice samples (more than 50 cm for the Dome Fuji core). In the clathrate hydrate zone, the scatter around the orbital-scale variability decreases with depth, indicating diffusive smoothing of delta O-2/N-2 and delta Ar/N-2. A simple gas diffusion model was used to reproduce the smoothing and thus constrain their permeation coefficients. The relationship between delta Ar/N-2 and delta O-2/N-2 is markedly different for the datasets representing bubble close-off (slope similar to 0.5), bubble-clathrate hydrate transformation (similar to 1), and post-coring gas loss (similar to 0.2), suggesting that the contributions of the mass-independent and mass-dependent fractionation processes are different for those cases. The method and data presented here may be useful for improving the orbital dating of deep ice cores over the multiple glacial cycles and further studying non-insolation-driven signals (e.g., atmospheric composition) of these gases.
  • Tsutomu Uchida, Hiroshi Miyoshi, Kenji Yamazaki, Kazutoshi Gohara
    ENERGIES 14 12 2021年06月 
    When gas hydrates dissociate into gas and liquid water, many gas bubbles form in the water. The large bubbles disappear after several minutes due to their buoyancy, while a large number of small bubbles (particularly sub-micron-order bubbles known as ultra-fine bubbles (UFBs)) remain in the water for a long time. In our previous studies, we demonstrated that the existence of UFBs is a major factor promoting gas hydrate formation. We then extended our research on this issue to carbon dioxide (CO2) as it forms structure-I hydrates, similar to methane and ethane hydrates explored in previous studies; however, CO2 saturated solutions present severe conditions for the survival of UFBs. The distribution measurements of CO2 UFBs revealed that their average size was larger and number density was smaller than those of other hydrocarbon UFBs. Despite these conditions, the CO2 hydrate formation tests confirmed that CO2 UFBs played important roles in the expression of the promoting effect. The analysis showed that different UFB preparation processes resulted in different promoting effects. These findings can aid in better understanding the mechanism of the promoting (or memory) effect of gas hydrate formation.
  • Ryo Sugimoto, Yuhiro Segawa, Akio Suzuta, Yuji Kunisada, Tsutomu Uchida, Kenji Yamazaki, Kazutoshi Gohara
    JOURNAL OF PHYSICAL CHEMISTRY C 125 5 2900 - 2906 2021年02月 
    Single-atom catalysts are attracting attention due to their superior catalytic activity and cost. Nitrogen (N) enhances the stability of single platinum (Pt) atoms on graphene because Pt atoms dispersed by plasma sputtering in an N-2 atmosphere are less likely to aggregate. However, the atomic structure of Pt and N on graphene has not been clarified. Here, we experimentally revealed the atomic arrangement of Pt, N, and carbon (C) by scanning transmission electron microscopy and electron energy loss spectroscopy. Pt and N atoms were adsorbed near the step edge of nanographene stacked on single-layer pristine graphene rather than on the terrace. The density functional theory (DFT) calculations using the experimental structure confirmed that the single Pt atom has high stability because N strengthens the bond between Pt and C at the step edge. In addition to a large decrease in the population of Pt 5d(xy)-orbital, an increase in the population of 5d(yz)-orbital was observed.
  • Tsutomu Uchida, Ike Nagamine, Itsuka Yabe, Tatsunori Fukumaki, Ai Oyama, Brandon Yoza, Norio Tenma, Stephen M. Masutani
    ENERGIES 13 15 3938 - 3938 2020年08月 [査読有り][通常論文]
     
    To investigate the temperature dependency of the methane bubble dissolution rate, buoyant single methane bubbles were held stationary in a countercurrent water flow at a pressure of 6.9 MPa and temperatures ranging from 288 K to 303 K. The 1 to 3 mm diameter bubbles were analyzed by observation through the pressure chamber viewport using a bi-telecentric CCD camera. The dissolution rate in artificial seawater was approximately two times smaller than that in pure water. Furthermore, it was observed that the methane bubble dissolution rate increased with temperature, suggesting that bubble dissolution is a thermal activation process (the activation energy is estimated to be 9.0 kJ/mol). The results were different from the expected values calculated using the governing equation for methane dissolution in water. The dissolution modeling of methane bubbles in the mid-to-shallow depth of seawater was revised based on the current results.
  • Tsutomu Uchida, Hiroshi Miyoshi, Ren Sugibuchi, Akio Suzuta, Kenji Yamazaki, Kazutoshi Gohara
    FRONTIERS IN CHEMISTRY 8 480-1 - 480-10 2020年06月 [査読有り][通常論文]
     
    To investigate experimentally how ultra-fine bubbles (UFBs) may promote hydrate formation, we examined the formation of propane (C3H8) hydrate from UFB-infused water solution using two preparation methods. In one method, we used C3H8-hydrate dissociated water, and in the other, C3H8-UFB-included water prepared with a generator. In both solutions, the initial conditions had a UFB number density of up to 10(9)mL(-1). This number density decreased by only about a half when stored at room temperature for 2 days, indicating that enough amount of UFBs were stably present at least during the formation experiments. Compared to the case without UFBs, the nucleation probabilities within 50 h were similar to 1.3 times higher with the UFBs, and the induction times, the time period required for the bulk hydrate formation, were significantly shortened. These results confirmed that UFB-containing water promotes C3H8-hydrate formation. Combined with the UFB-stability experiments, we conclude that a high number density of UFBs in water contributes to the hydrate promoting effect. Also, consistent with previous research, the present study on C(3)H(8)hydrates showed that the promoting effect would occur even in water that had not experienced any hydrate structures. Applying these findings to the debate over the promoting (or "memory") effect of gas hydrates, we argue that the gas dissolution hypothesis is the more likely explanation for the effect.
  • Uchida T, Furukawa M, Kikawada T, Yamazaki K, Gohara K
    Cryobiology 90 30 - 40 2019年10月 [査読有り][通常論文]
     
    Chinese hamster ovary cells (CHO K1 cells) in which the trehalose transporter (TRET1) is expressed can have greater cryoprotection than ordinary CHO Ki cells. This study examines the uptake characteristics of trehalose into cells via TRET1 and determines the influence of intracellular trehalose on the freeze thaw viabilities. In our experiments, the intracellular trehalose concentration is controlled by the extracellular trehalose concentration and the immersion time in a freezing solution. In this freezing solution, both kinds of CHO Kl cells are independently dispersed with various amount of trehalose, and then put into the CO2 incubator for 0-6 h. After a set immersion time, the cell -suspended sample is cooled to 193 K, stored for 1 week, then quickly thawed at 310 K and its viability measured. The uptake amount of intracellular trehalose is measured before freezing. We find an upper limit for the uptake amount of trehalose when the extracellular trehalose concentration is about 400 mM, at which the freeze thaw viability is the highest. When the extracellular trehalose concentration exceeds 400 mM, shorter immersion times are needed to obtain the maximum freeze thaw viability. Also, longer immersion weakens the cells. Our analyses indicate that when the extracellular trehalose-concentration is less than 400 mM, the trehalose uptake occurs more slowly with less dehydration, resulting in less stress on the cell. When the extracellular trehalose concentration exceeds the saturation level, the cell is stressed by the excess dehydration due to the remaining osmotic pressure, with apoptosis occurring before freezing.
  • Tsutomu UCHIDA(内田努), Maho FURUKAWA(古川真帆), Takahiro KIKAWADA(黄川田隆洋), Kenji YAMAZAKI(山崎憲慈), Kazutoshi GOHARA(郷原一寿)
    氷河情報センター 37 1 - 9 公益社団法人 日本雪氷学会 2019年 [査読有り][通常論文]
     
    Trehalose acts as a non-toxic cryoprotectant agent (CPA) to CHO-TRET1 cells, which are CHO-K1 cells that express the trehalose transporter. This study examines the viabilities during long-term storage at 193 K of cryopreserved CHO-TRET1 cells with trehalose, and compares them to the corresponding viabilities with 10 wt%-dimethyl sulfoxide (DMSO). The cryopreserved samples are selected to have a 1-week storage viability exceeding 0.7. Results show that this high viability with trehalose is maintained at the same level for about one year of storage, and gradually decrease to about 0.55 +/- 0.16 after about 2.5 years. Comparison of this result with the corresponding case with DMSO suggests that the cryoprotective ability of trehalose is slightly weaker than that of DMSO at this temperature. We discuss the effect of recrystallization of ice, and also the biological damaging, on the viabilities. Then we concluded that the cell membrane slowly degrades at 193 K, with the rate being a little faster with trehalose than with DMSO.
  • 内田 努, 木虎 竜一, 郷原 一寿
    Trends in Medicine 18 4 1 - 10 2018年06月 [査読有り][通常論文]
  • Tsutomu Uchida, Hitoshi Nishikawa, Nobuki Sakurai, Masashi Asano, Naoki Noda
    NANOMATERIALS 8 3 152-1 - 152-12 2018年03月 [査読有り][通常論文]
     
    Water containing ultra-fine bubbles (UFB) may promote plant growth. But, as UFBs are too small to distinguish from other impurities in a nutrient solution, it is not known if UFBs survive transport from the water source to the rhizosphere. Here we use the freeze-fracture replica method and a transmission electron microscope (TEM) to observe UFBs in the nutrient solutions used in a crop-growing system known as a plant factory. In this factory, TEM images taken from various points in the supply line indicate that the concentration of UFBs in the nutrient solution is conserved, starting from their addition to the nutrient solution in the buffer tank, through the peat-moss layer, all the way to the rhizosphere. Measurements also show that a thin film formed on the surface of UFBs in the nutrient solution, with greater film thickness at the rhizosphere. This film is considered to be made from the accumulation of impurities coming from solute and the peat-moss layer.
  • Tsutomu Uchida, Koichiro Shimada, Ryutaro Tanabe, Tatsuya Kubota, Daisuke Ito, Kenji Yamazaki, Kazutoshi Gohara
    IBRO REPORTS 3 45 - 54 2017年12月 [査読有り][通常論文]
     
    Mature rat cortical neuronal networks cultured on multi-electrode arrays (MEAs) are known to show spontaneous synchronized bursts accompanied by independent single spikes. The spontaneous synchronized bursts can be inhibited by Xe gas. In this study, we adjust the Xe gas pressure to control the amount of Xe in a neuron-cultured MEA medium. We show that the synchronized bursts cease completely within several minutes by applying Xe gas at partial pressures above 0.3 MPa. After depressurizing and purging with fresh air, the synchronized bursts recover to their original frequency. Thus, we confirmed that Xe acts as a network-activity inhibitor of the cultured neuronal network on MEAs. But below 0.3 MPa, the synchronized bursts are inhibited only partially, depending on the Xe partial pressure. Based on the partial-pressure influence on the change of the neuronal network activities, we find the critical concentration of Xe for the inhibition effect to be approximately 9.5 mM, a value above which more than 90% of the synchronized burst activity is inhibited. Further systematic observations with Xe-air mixed gases show that pressurized air with a small amount of Xe suppresses the inhibition of synchronized bursts, suggesting an air component that can accelerate the synchronized bursts. (C) 2017 The Authors. Published by Elsevier Ltd on behalf of International Brain Research Organization. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
  • Tsutomu Uchida, Maho Furukawa, Takahiro Kikawada, Kenji Yamazaki, Kazutoshi Gohara
    CRYOBIOLOGY 77 50 - 57 2017年08月 [査読有り][通常論文]
     
    Trehalose is a promising natural cryoprotectant, but its cryoprotective effect is limited due to difficulties in transmembrane transport. Thus, expressing the trehalose transporter TRET1 on various mammalian cells may yield more trehalose applications. In this study, we ran comparative cryopreservation experiments between the TRET1-expressing CHO-K1 cells (CHO-TRET1) and the CHO-K1 cells transfected with an empty vector (CHO-vector). The experiments involve freezing under various trehalose concentrations in an extracellular medium. The freeze-thawing viabilities of CHO-TRET1 cells are higher than those of CHO-vector cells for most freezing conditions. This result differs from control experiments with a transmembrane type cryoprotectant, dimethyl sulfoxide (Me2SO), which had similar viabilities in each condition for both cell types. We conclude that the trehalose loaded into the cells with TRET1 significantly improves the cryoprotective effect. The higher viabilities occurred when the extracellular trehalose concentration exceeded 200 mM, with 250-500 mM being optimal, and a cooling rate below 30 K/min, with 5-20 K/min being optimal. (C) 2017 Elsevier Inc. All rights reserved.
  • Tsutomu Uchida, Bjorn Kvamme, Richard B. Coffin, Norio Tenma, Ai Oyama, Stephen M. Masutani
    ENERGIES 10 6 2017年06月 [査読有り][通常論文]
     
    The International Workshop on Methane Hydrate (MH) Research and Development (the Fiery Ice Workshop) began in 2001 with the goal of promoting laboratory and field research collaborations and providing a forum to share new knowledge on MH pertaining to coastal stability, climate change, and energy. Ten workshops have been held over the past 15 years in different countries. Each workshop has included presentations on national programs and policy areas, and new research, along with breakout sessions that focused on current key topics. Two or three concurrent breakout sessions were conducted twice during each workshop. In this paper, we review the breakout sessions on hydrate fundamental properties with the goal of identifying the major accomplishments and changes in hydrate science and engineering related to determining fundamental MH properties over the past 15 years.
  • Vladimir Istomin, Evgeny Chuvilin, Boris Bukhanov, Tsutomu Uchida
    COLD REGIONS SCIENCE AND TECHNOLOGY 137 60 - 67 2017年05月 [査読有り][通常論文]
     
    A new method is proposed for estimating the contents of liquid water in equilibrium with bulk ice and bulk gas hydrate in hydrophilic porous media. In this paper water content equilibrium with bulk ice is represented as unfrozen water, and water equilibrium with gas and gas hydrate is nonclathrate water. The method consists in measuring moisture-and temperature-dependent pore water potential (and water activity) in natural sediments or synthetic porous samples at atmospheric pressure, with subsequent thermodynamic calculations of pressure-and temperature -dependent unfrozen and/or nonclathrate water contents using the measured data. The experiments are applied to synthetic samples with known pore sizes (controlled pore glasses, CPG) and natural kaolinite and polymineral clay samples. Water potential and thermodynamic activity are measured on a Decagon Devices WP4T meter. Thermodynamic calculations for water contents in hydrophilic porous media are performed using specially derived equations for temperature-dependent unfrozen water in equilibrium 'bulk ice -confined water' systems (at negative Celsius temperatures) and for nonclathrate water in equilibrium 'ga -bulk gas hydrate-confined water' systems depending on both temperature and pressure of gas hydrate former (methane, natural gas, etc.). The water contents in porous samples estimated with the new method show good agreement with the results of direct contact measurements for equilibrium water in contact with ice or gas hydrate at given temperatures and pressures.(C) 2017 Elsevier B.V. All rights reserved.
  • Toshimitsu Sakurai, Hiroshi Ohno, Hideaki Motoyama, Tsutomu Uchida
    JOURNAL OF RAMAN SPECTROSCOPY 48 3 448 - 452 2017年03月 [査読有り][通常論文]
     
    Climatic signals in deep ice cores, particularly from ion concentrations, may be affected by the diffusion of liquid solution along grain boundaries of ice. Such solutions include sulfates. Because of the difficulty of detecting sulfate liquids in the ice matrix, we must infer the phase of the sulfates from the ice temperature and inclusion properties. In this study, we use micro-Raman spectroscopy to determine the phase of three sulfate micro-inclusions in the Dome Fuji ice core at 2798.5m depth. Using a temperature-ramp test, we find a peak position at 984 cm(-1) and a change in the full width at half maximumof the S-O stretching mode that identifies the sulfate in the micro-droplets. Considering the peak position and full width at half maximum of sulfate inclusions, we argue that the sulfate would have existed as a micro-droplet liquid on an air-clathrate hydrate in the ice. Additionally, the increase in the low frequencies of the Raman spectrum below 30 cm(-1) that we detect can be generally used to identify liquids in natural ice. Our investigation also indicates that the surface of air-clathrate hydrates in ice is a preferred location for liquid micro-inclusions. Copyright (c) 2016 John Wiley & Sons,
  • Tsutomu Uchida, Kenji Yamazaki, Kazutoshi Gohara
    JOURNAL OF PHYSICAL CHEMISTRY C 120 47 26620 - 26629 2016年12月 [査読有り][通常論文]
     
    Gas-hydrate crystals have important roles in various energy and environmental issues and also have potential industrial applications. Yet their formation and dissociation mechanisms remain unclear. To accelerate their crystallization, one can use a thermal hysteresis process called the "memory effect", which is recognized as a shortening of the induction time of gas hydrate nucleation. Although its mechanism is still under debate, submicron-sized bubbles, called "micro- and nanobubbles (MNBs)", that are generated after the hydrate dissociation are thought to play an important role. In this study, we use a transmission electron microscope to observe freeze-fracture replicas of the ethane (C2H6)-hydrate dissociated solution to identify the existence of MNBs. We find that a significant number of MNBs remain dispersed in the dissociated solution for more than 1 day. We then measure the induction time of C2H6-hydrate formation under stirred conditions with and without such MNB solutions. Not only in the C2H6-hydrate dissociated water but also in the C2H6-bubbling solution we identify a significant and clear memory effect. We apply these findings to the mechanism of the memory effect in gas -hydrate crystallization, particularly the role of MNBs on the memory effect.
  • Tsutomu Uchida, Kenji Yamazaki, Kazutoshi Gohara
    KOREAN JOURNAL OF CHEMICAL ENGINEERING 33 5 1749 - 1755 2016年05月 [査読有り][通常論文]
     
    Gas hydrate crystals have a structure in which one molecule is enclathrated in a cage of water molecules. When such a crystal dissociates in water, each enclathrated molecule, generally vapor at standard temperature and pressure, directly dissolves into the water. After the solution is supersaturated, excess gas molecules from further dissociation start forming small bubbles called micro- and nano-bubbles (MNBs). However, it is difficult to identify such small bubbles dispersed in liquid because they are smaller than a microscope's optical resolution. To confirm the formation of MNBs after gas hydrate dissociation, we used a transmission electron microscope (TEM) to analyze freeze-fracture replicas of CH4-hydrate dissociation solution. The TEM images indicate the existence of MNBs in the solution, with a number concentration similar to that from a commercially supplied generator. Raman spectroscopic measurements on the CH4-hydrate dissociated solution were then used to confirm that the MNBs contain CH4 vapor, and to estimate experimentally the inner pressure of the CH4 MNBs. These results suggest that the dissociation of gas hydrate crystals in water is a simple, effective method to obtain MNB solution. We then discuss how such MNBs may play a key role in the memory effect of gas-hydrate recrystallization.
  • Shu Liu, Seiichi Oshita, Yoshio Makino, Qunhui Wang, Yoshinori Kawagoe, Tsutomu Uchida
    ACS SUSTAINABLE CHEMISTRY & ENGINEERING 4 3 1347 - 1353 2016年03月 [査読有り][通常論文]
     
    Nanobubbles (NBs) have been reported to be effective at accelerating the metabolism of living organisms, but the mechanism is not yet well understood. In this study, the production of reactive oxygen species (ROS) by NBs and its effect on seed germinations were investigated. The fluorescence response of APF to NB water was measured. It changed depending on the NB number density which decreased with storage time. This indicated that NBs could produce ROS and the amount of ROS had positive correlation with the NB number density. The fluorescence intensity of APF increases linearly with the concentration of H2O2 in the range of 0-1 mM. Just after the NB generation, the oxidative capacities represented by amount of ROS of oxygen NB water and gas-mixture (air + nitrogen) NB water were estimated to be equivalent to 0.5 and 0.3 mM H2O2 respectively. The seed germination tests were performed in the NB water, distilled water and H2O2 solutions. The germination rate at each observation times of seeds submerged in gas-mixture NB water and 0.3 mM H2O2 solutions were both higher than those submerged in distilled water. The amounts of superoxide radicals in the seeds were detected using NBT staining. The results of absorbance data proved that the amounts of O-2(center dot-) in seeds submerged in gas-mixture NB water and in 0.3 mM H2O2 solution were similar and significantly higher than those in the distilled water. These results indicated that moderate level of exogenous ROS produced by NB water played an important role in seed germination.
  • Tsutomu Uchida, Shu Liu, Masatoshi Enari, Seiichi Oshita, Kenji Yamazaki, Kazutoshi Gohara
    NANOMATERIALS 6 2 2016年02月 [査読有り][通常論文]
     
    Micro- and nanobubbles (MNBs) are potentially useful for industrial applications such as the purification of wastewater and the promotion of physiological activities of living organisms. To develop such applications, we should understand their properties and behavior, such as their lifetime and their number density in solution. In the present study, we observed oxygen MNBs distributed in an electrolyte (NaCl) solution using a transmission electron microscope to analyze samples made with the freeze-fracture replica method. We found that MNBs in a 100 mM NaCl solution remain for at least 1 week, but at higher concentrations decay more quickly. To better understand their lifetimes, we compared measurements of the solution's dissolved oxygen concentration and the -potential of the MNBs. Our detailed observations of transmission electron microscopy (TEM) images allows us to conclude that low concentrations of NaCl stabilize MNBs due to the ion shielding effect. However, higher concentrations accelerate their disappearance by reducing the repulsive force between MNBs.
  • 内田 努, 山崎 憲慈, 郷原 一寿
    日本エネルギー学会大会講演要旨集 25 44 - 45 一般社団法人 日本エネルギー学会 2016年 

    Gas hydrate crystal has the structure which has advantage for generating the micro- and nanobubbles (MNBs) when the crystal is dissociated in water. The freeze-fracture replicas of the gas-hydrate dissociated solution were observed via a transmission electronic microscope (TEM) to confirm that various guest hydrates have such properties. Raman spectroscopic observations on the CH4 hydrate dissociated solution indicated that the existing MNBs were originated from CH4 hydrates, and that the inner pressure of MNB was about 7 MPa. Based on the MNB distribution data and the inner pressure, we discuss the role of MNBs on the memory effect of gas hydrate formation.

  • Hironori D. Nagashima, Satoshi Takeya, Tsutomu Uchida, Ryo Ohmura
    SCIENTIFIC REPORTS 6 19354 - 19354 2016年01月 [査読有り][通常論文]
     
    To investigate the preservation of CO2 clathrate hydrate in the presence of sugar for the novel frozen dessert, mass fractions of CO2 clathrate hydrate in CO2 clathrate hydrate samples coexisting with trehalose were intermittently measured. The samples were prepared from trehalose aqueous solution with trehalose mass fractions of 0.05 and 0.10 at 3.0 MPa and 276.2 K. The samples having particle sizes of 1.0 mm and 5.6-8.0 mm were stored at 243.2 K and 253.2 K for three weeks under atmospheric pressure. The mass fractions of CO2 clathrate hydrate in the samples were 0.87-0.97 before the preservation, and CO2 clathrate hydrate still remained 0.56-0.76 in the mass fractions for 5.6-8.0 mm samples and 0.37-0.55 for 1.0 mm samples after the preservation. The preservation in the trehalose system was better than in the sucrose system and comparable to that in the pure CO2 clathrate hydrate system. This comparison indicates that trehalose is a more suitable sugar for the novel frozen carbonated dessert using CO2 clathrate hydrate than sucrose in terms of CO2 concentration in the dessert. It is inferred that existence of aqueous solution in the samples is a significant factor of the preservation of CO2 clathrate hydrate in the presence of sugar.
  • Tsutomu Uchida, Masafumi Nagayama, Kenji Yamazaki, Kazutoshi Gohara, Amadeu K. Sum
    CANADIAN JOURNAL OF CHEMISTRY 93 8 831 - 838 2015年08月 [査読有り][通常論文]
     
    The Raman spectra of liposomes were measured under xenon pressures and low temperatures to observe the spectra changes accompanying the gel to liquid crystalline phase transition of the liposomes. C-H stretching bonds of the lipids in the liposome were slightly red shifted at approximately 285 K and atmospheric pressure, which coincided well with the phase transition condition. This Raman peak shift was observed at lower temperatures and related linearly to the xenon pressures. The xenon pressure dependence on the phase transition temperature was in good agreement with the DSC measurements, and the red shifts of Raman peaks supported the molecular mechanism of interaction between xenon and phospholipid bilayers suggested by the MD simulations. The phase transition measurements under xenon pressure with the microscopic Raman spectroscopy were applied to cultured neuronal networks to observe the interaction of dissolved xenon with the cell membrane and the surrounding water.
  • Tsutomu Uchida, Daisuke Kishi, Toshiki Shiga, Masafumi Nagayama, Kazutoshi Gohara
    JOURNAL OF CHEMICAL AND ENGINEERING DATA 60 2 284 - 292 2015年02月 [査読有り][通常論文]
     
    Clathrate hydrates have recently received attention as novel storage and transportation materials of natural gases. For the economical storage or transportation of the produced natural gas hydrates, the effect of sintering should be considered because the hydrate particles would be stored in relatively moderate conditions. In the present study, microscopic observations were carried out on gas hydrate particles to investigate their sintering properties. The spherical gas hydrates were prepared from spherical ice particles with carbon dioxide (CO2) or ethane (C2H6) pressures higher than the dissociation ones. The initial sintering rate of CO2 hydrates at temperatures between 271.4 K and 278.2 K and pressures between 1.9 MPa and 2.9 MPa was similar to that of THF hydrate under saturated conditions reported previously. Conversely, the C2H6 hydrate particles were hard to sinter at temperatures between 273.5 K and 281.7 K and pressures between 0.5 MPa and 2.0 MPa. We discussed the sintering process of gas hydrates and their rate-determining process which depended on guest molecules under their stable conditions. The sintering of methane hydrate particles under stable and self-preservation conditions was also investigated to demonstrate the storage and transportation conditions of natural gas hydrate particles.
  • 内田 努, 古川 真帆, 黄川田 隆洋, 山崎 憲慈, 郷原 一寿
    雪氷研究大会講演要旨集 2015 156 - 156 公益社団法人 日本雪氷学会／日本雪工学会 2015年
  • 内田 努, 山崎 憲慈, 郷原 一寿
    日本エネルギー学会大会講演要旨集 24 60 - 61 一般社団法人日本エネルギー学会 2015年 
    Gas hydrate crystals have the structure in which one molecule is enclathrated in a cage constructed by water molecules. When this crystal is dissociated in water, it is considered that the gas molecules are released one by one into water to be dissolved. However, since the guest molecule is hydrophobic, a part of released molecules from the gas hydrate could form bubbles. We tried to observe these fine bubbles directly by forming the freeze-fracture replica and using a transmission electronic microscope (TEM). TEM images showed the existence of sub-micron-order fine bubbles in the dissociated solution. Then we discussed the role of the nanobubbles playing as the main reason of the memory effect of the gas-hydrate reformation.
  • Tsutomu Uchida, Masafumi Nagayama, Kazutoshi Gohara, Amadeu K. Sum
    生物物理 54 1 S287  一般社団法人 日本生物物理学会 2014年
  • Spontaneous and evoked activity in patterned multi-cluster neuronal networks
    M. Anisimova, K. Yokoyama, D. Ito, M. Suzuki, T. Uchida, K. Gohara
    Proc. MEA Meeting 170-171  2014年 [査読有り][通常論文]
  • Tsutomu Uchida, Keita Yasuda, Yuya Ot, Renkai Shen, Ryo Ohmura
    JOURNAL OF GLACIOLOGY 60 224 1111 - 1116 2014年 [査読有り][通常論文]
     
    We apply new phase-equilibrium data of air-clathrate hydrates to the distribution of air hydrates in deep ice sheets to better understand their nucleation conditions. By comparing the depths at which the hydrates first appear to the phase-equilibrium condition, we estimated the critical size of an air-hydrate nucleus in an ice sheet to be similar to 50 nm. The estimated energy barrier for nucleation, based on the temperature dependence of supersaturation, is much smaller than that estimated previously for the pure ice system. Thus, the bubble surface may either act as a type of heterogeneous nucleus, or contain heterogeneous nuclei, for hydrate formation. Competition between nucleation-promotion and nucleation-inhibition factors may increase variation in nucleation rates, resulting in variation of the depth range of the bubble hydrate transition zones.
  • Keita Yasuda, Yuya Oto, Renkai Shen, Tsutomu Uchida, Ryo Ohmura
    JOURNAL OF CHEMICAL THERMODYNAMICS 67 143 - 147 2013年12月 [査読有り][通常論文]
     
    Contained in this paper are the three phase equilibrium conditions of the (ice + clathrate hydrate + guest-rich) vapour in the (nitrogen + water) and the modelled (air + water) systems at temperatures below the freezing point of water. The precise determination of the equilibrium conditions in those systems are of importance for the analysis of the past climate change using the cored samples from the ice sheets at Antarctica and Greenland because the air hydrates keep the ancient climate signals. The mole ratio of the modelled air composed of nitrogen and oxygen is 0.790:0.210. The equilibrium conditions were measured by the batch, isochoric procedure. The temperature range of the measurements in the nitrogen hydrate forming system is (244.05 < T < 266.55) K and the corresponding equilibrium pressure range is (7.151 < p < 12.613) MPa. The temperature range of the measurements in the modelled air hydrate forming system is (242.55 < T < 267.85) K, and the corresponding equilibrium pressure range is (6.294 < p < 12.144) MPa. The data obtained quantitatively compared with the previously reported data. (c) 2013 Elsevier Ltd. All rights reserved.
  • Masaaki Suzuki, Koji Ikeda, Munehiro Yamaguchi, Suguru N. Kudoh, Keiko Yokoyama, Ryota Satoh, Daisuke Ito, Masafumi Nagayama, Tsutomu Uchida, Kazutoshi Gohara
    BIOMATERIALS 34 21 5210 - 5217 2013年07月 [査読有り][通常論文]
     
    We studied neuronal cell patterning on a commercial multi-electrode array (MEA). We investigated the surface chemical modification of MEA in order to immobilize Poly-D-lysine (PDL) and then to pattern PDL with a photolithographic method using vacuum ultraviolet light (VUV). We have clarified that the PDL layer was not fully decomposed but was partially fragmented by short-time irradiation with VUV, resulting in a change in the cell adhesiveness of the PDL. We succeeded in patterning primary rat cortex cells without manipulating the cells on MEA more than two months. This cell-adhesiveness change induced by VUV can be applied to any immobilized PDL on other kinds of MEA and culturing substrate. We conducted electrophysiological measurements and found that the patterned neuronal cells were sufficiently matured and developed neural networks, demonstrating that our patterning method is useful for a neuronal network analysis platform. (C) 2013 Elsevier Ltd. All rights reserved.
  • T. Uchida, A. K. Sum
    低温科学 71 105 - 110 北海道大学低温科学研究所 = Institute of Low Temperature Science, Hokkaido University 2013年03月 [査読有り][通常論文]
     
    Raman spectroscopic analysis was applied to observe the phase transition of dielaidoylphosphatidylcholine (DEPC) liposome under 0.5 MPa Xe pressurization conditions. After the band assignments on DEPC molecule, detailed measurements of the methylene C-H stretching mode spectra were performed. The data revealed that all three peaks associated with DEPC, including the C-H stretching mode,shifted to lower wavenumbers at lower temperatures and that the relative intensities of Raman spectra changed simultaneously. These changes on Raman spectra occurred at approximately 280 K, suggesting a gel to liquid crystalline phase transition. This temperature is lower than that under atmospheric pressure, and it is consistent with DEPC liposomes exposed to Xe measured with differential scanning calorimetric under similar conditions.
  • 奥平俊樹, 永山昌史, 郷原一寿, 内田努
    低温科学 71 81 - 89 北海道大学低温科学研究所 = Institute of Low Temperature Science, Hokkaido University 2013年03月 [査読有り][通常論文]
     
    細胞を生きたまま保存することができれば, 一つの個体から多くの実験試料を採取し安定供給することができ, 産業分野に大きく貢献できる. しかし心臓を構成する心筋細胞など需要が多いにもかかわらず保存が困難な細胞も存在する. そこで本研究では, 分散された初代ラット心筋細胞の保存条件を, キセノンなどのガスを印加し室温以上の温度まで保存温度を引き上げる技術について検討した. 9.4～35℃の範囲で種々のガスを0.5MPa印加して培養液中に分散させた心筋細胞を72時間保存し, 保存後の細胞を生理条件下で培養してその機能の正常性を評価した. その結果, 不活性ガス, 窒素ガス, 炭化水素ガスなどを印加した場合は, ガスを印加しなかった保存細胞との違いが見られず, ガスの印加効果が本実験条件内では見られなかった. しかし酸素を含んだ混合ガスを印加したところ, 高温まで分散状態が保たれたが, その後の培養試験で多くの細胞が劣化または死滅することがわかり, 高濃度酸素が保存期間中に細胞の接着機能に影響を及ぼすことがわかった.If we can preserve the cells, we contribute significantly to the industrial demands by the stable supply of a number of experimental samples from one individual. However, some cells exist in high demand although it is difficult to preserve, such as the cardiomyocytes that make up the heart. In this study, we have examined the preservation technique by applying gases to rise the storage temperature limit of the dispersed primary rat cardiomyocytes. We evaluated the health of its functions under physiological conditions by culturing the cells after the storage by applying 0.5MPa gases for 72 hours at temperatures ranged from 9.4 to 35℃. As a result, we observed no difference between the preserved cells with and without applying inert gas, nitrogen gas and hydrocarbon gas in the present experimental conditions. However, we found the significant negative effect by applying the mixed gas containing oxygen during the culture test although the dispersed condition was kept during the preservation period at higher temperature. It is considered that the dissolved oxygen would inhibit the adhesion function of cardiomyocytes.
  • Seiichi Oshita, Tsutomu Uchida
    Bio-Nanotechnology: A Revolution in Food, Biomedical and Health Sciences 506 - 516 2013年01月04日 [査読有り][通常論文]
     
    After an overview of past research on microbubbles and nanobubbles, our research is introduced, in which dynamic light-scattering measurements indicate particles a few hundred nanometers in diameter. Good repeatability of the particle size distributions of air and oxygen bubbles in water was maintained for some time, and then the size distribution fluctuated and the bubbles disappeared. This phenomenon suggests the existence of nanobubbles (NBs). Zeta potential measurements showed that the NBs are negatively charged in the range of pH used, and a higher electrical charge was observed for oxygen NBs. As an application, transmission electron microscopy and the freeze-fracture replica technique were applied to the direct observation of oxygen NBs generated in wastewater from inositol extraction. Spherical objects were observed, which were believed to be NBs with diameters ranging from 5 to 9 × 10-7 m. It was confirmed that the NBs adsorbed impurities effectively from the solution on their surface. © 2013 John Wiley & Sons, Ltd.
  • 内田 努, 菅原武, 大垣一成, 田中秀樹, 竹谷敏, 谷篤史
    高圧力の科学と技術 23 2 141 - 147 日本高圧力学会 2013年 [査読有り][通常論文]
     
    The symposium "Development in Scientific Researches on Gas Hydrates" was held at the 53< sup> rd< /sup> High Pressure Conference of Japan on November 2012. After some presentations in the symposium, the possibilities of improving or transcending the van der Waals & Platteeuw model for the phase equilibrium estimation including clathrate hydrate phase were discussed. In this article, a part of the discussion was reported.
  • Renkai Shen, Kyoichi Tezuka, Tsutomu Uchida, Ryo Ohmura
    JOURNAL OF CHEMICAL THERMODYNAMICS 53 27 - 29 2012年10月 [査読有り][通常論文]
     
    The four-phase equilibrium conditions of (vapor + liquid + hydrate + ice) were measured in the system of (CO2 + 2,2-dimethylbutane + water). The measurements were performed within the temperature range (254.2 to 270.2) K and pressure range (0.490 to 0.847) MPa using an isochoric method. Phase equilibrium conditions of hydrate formed in this study were measured to be at higher temperatures and lower pressures than those of structure I CO2 simple hydrate. The largest difference in the equilibrium pressures of structure I CO2 hydrate and the hydrate formed in the present study was 0.057 MPa at T = 258.3 K. On the basis of the four-phase equilibrium data obtained, the quintuple point for the (ice + structure I hydrate + structure H hydrate + liquid + vapor) was also determined to be T = 266.4 K and 0.864 MPa. The results indicate that structure H hydrate formed with CO2 and 2,2-dimethylbutane is stable exclusively at the temperatures below the quintuple temperature. (C) 2012 Elsevier Ltd. All rights reserved.
  • T. Uchida, S. Suzuki, Y. Hirano, D. Ito, M. Nagayama, K. Gohara
    NEUROSCIENCE 214 149 - 158 2012年07月 [査読有り][通常論文]
     
    Xenon (Xe) and other inert gases produce anesthesia via an inhibitory mechanism in neuronal networks. To better understand this mechanism, we measured the electrical signals from cultured rat cortical neuronal networks in a multi-electrode array (MEA) under an applied Xe pressure. We used the MEA to measure the firing of the neuronal network with and without Xe gas pressurized to 0.3 MPa. The MEA system monitored neuronal spikes on 16 electrodes (each 50 x 50 mu m(2)) at a sampling rate of 20 kHz. The embryo rat cortical cells were first cultured on MEAs without Xe for approximately 3 weeks, at which time they produced synchronized bursts that indicate maturity. Then, with an applied Xe pressure, the synchronized bursts quickly ceased, whereas single spikes continued. The Xe-induced inhibition-recovery of neuronal network firing was reversible: after purging Xe from the system, the synchronized bursts gradually resumed. Thus, Xe did not inhibit single neuron firing, yet reversibly inhibited the synaptic transmission. This finding agrees with the channel-blocker and a modified-hydrate hypothesis of anesthesia, but not the lipid-solubility hypothesis. (c) 2012 IBRO. Published by Elsevier Ltd. All rights reserved.
  • 内田努, 宮村謙一郎, 永山昌史, 郷原一寿
    低温生物工学会誌 58 1 59 - 63 低温生物工学会 2012年 [査読有り][通常論文]
     
    培養液中に分散させたラット心筋細胞の凍結保存における至適DMSO濃度が10%前後である理由を明らかにするため、水溶液および凍結液の熱特性測定とDMSOの細胞毒性測定を行った。示差熱量計による凍結液の測定結果から、5〜10%以上のDMSO濃度では凝固点降下により融点を最大氷結晶生成帯以下に下げ、凍結細胞が融解時に細胞外氷結晶の再結晶によるメカニカルストレスを受けないようにすることが示唆された。一方、凍結液への浸漬試験結果から、DMSOは心筋細胞の機能を障害することが確認され、その影響が濃度10%以上で顕著になることが示唆された。
  • 内田 努, 安田 啓太, 大戸 悠也, 大村 亮
    雪氷研究大会講演要旨集 2012 139 - 139 公益社団法人 日本雪氷学会／日本雪工学会 2012年
  • Tsutomu Uchida, Masafumi Nagayama, Toshio Taira, Kyoko Shimizu, Masato Sakai, Kazutoshi Gohara
    CRYOBIOLOGY 63 3 279 - 284 2011年12月 [査読有り][通常論文]
     
    The increase in demand for primary cardiomyocytes necessitates advanced methods for their stable supply. In this study, we investigated the optimal temperature range for preserving dissociated cardiomyocytes for 72 h while maintaining their normal growth and beating functions. Neonatal rat cardiomyocytes dissociated by collagenase and suspended in the culture medium were preserved at temperatures from -2 to 35 degrees C for 72 h. The cardiomyocytes preserved at temperatures below 20 degrees C maintained the initial dispersed states, whereas they aggregated robustly at higher temperatures. The viability of the dispersed cells after preservation was more than 80%. After the preservation, the microscopic observations during the 7-days cultivation indicated that these dispersed cardiomyocytes grew normally to form a confluent monolayer, and beat spontaneously and regularly during culture, as did the fresh cells. These systematic evaluations indicated that the optimal temperature ranged from 3 to 20 degrees C. Below this optimal temperature range, the cell activities decreased slightly with temperature. The robustly aggregated cardiomyocytes exhibited weak growth and low beating rates, although some cardiomyocytes still survived. The optimal conditions, which consist of a wider temperature range and longer preservation period than the present commercially used conditions, allowed milder temperature control and thus more economical transportation for the dissociated primary cardiomyocytes. (C) 2011 Elsevier Inc. All rights reserved.
  • Munehiro Yamaguchi, Koji Ikeda, Masaaki Suzuki, Ai Kiyohara, Suguru N. Kudoh, Kyoko Shimizu, Toshio Taira, Daisuke Ito, Tsutomu Uchida, Kazutoshi Gohara
    LANGMUIR 27 20 12521 - 12532 2011年10月 [査読有り][通常論文]
     
    Micropatterning techniques have become increasingly important in cellular biology. Cell patterning is achieved by various methods. Photolithography is one of the most popular methods, and several light sources (e.g., excimer lasers and mercury lamps) are used for that purpose. Vacuum ultraviolet (VUV) light that can be produced by an excimer lamp is advantageous for fabricating material patterns, since it can decompose organic materials directly and efficiently without photoresist or photosensitive materials. Despite the advantages, applications of VUV light to pattern biological materials are few. We have investigated cell patterning by using a template of a microstructured organosilane layer fabricated by VUV lithography. We first made a template of a microstructured organosilane layer by VUV lithography. Cell adhesive materials (poly(D-lysine) and polyethyleneimine) were chemically immobilized on the organosilane template, producing a cell adhesive material pattern. Primary rat cardiac and neuronal cells were successfully patterned by culturing them on the pattern substrate. Long-term culturing was attained for up to two weeks for cardiac cells and two months for cortex cells. We have discussed the reproducibility of cell patterning and made suggestions to improve it.
  • Tsutomu Uchida, Masato Kida, Jiro Nagao
    CHEMPHYSCHEM 12 9 1652 - 1656 2011年06月 [査読有り][通常論文]
  • Ice-shielding models for self-preservation of gas hydrates
    T. Uchida, T. Sakurai, T. Hondoh
    Journal of Chemistry and Chemical Engineering 5 8 691 - 705 2011年 [査読有り][通常論文]
  • Tsutomu Uchida, Atsushi Miyamoto, Atsushi Shin'yama, Takeo Hondoh
    JOURNAL OF GLACIOLOGY 57 206 1017 - 1026 2011年 [査読有り][通常論文]
     
    Air-hydrate crystals store most of the ancient air contained in deep ice sheets. We carried out microscopic observations of air-hydrate crystals below 2000 m depth within the ice core from Dome Fuji, Antarctica, to obtain their number and size distributions. We found that the number density continuously decreased with depth, whereas the average size increased, in contrast to findings from shallower depths. In addition, the characteristic perturbations in both number density and average size distribution with climatic changes almost disappeared, although they are clearly observed in shallow cores. These results indicate that the air-hydrate crystals grow considerably in deeper parts of the ice sheet, and this growth is accompanied by the diffusion of air molecules in the ice. The permeation coefficient of the air molecules in the ice sheet was estimated from the geometric parameters of the air-hydrate distributions. This is the first practical evidence comparable to the previous model estimations. It allows us to evaluate the impacts of the air-molecule migration in the ice sheet on the paleoclimatic information recorded in the deep ice cores.
  • Toshimitsu Sakurai, Hiroshi Ohno, Shinichiro Horikawa, Yoshinori Iizuka, Tsutomu Uchida, Kazuomi Hirakawa, Takeo Hondoh
    JOURNAL OF GLACIOLOGY 57 206 1027 - 1032 2011年 [査読有り][通常論文]
     
    This study clarifies changes in the chemical forms of microparticles during Termination I, the period of drastic climate change between the Last Glacial Maximum (LGM) and the Holocene. We determine the chemical forms of individual water-soluble microparticles through micro-Raman spectroscopy and compare the relative frequencies of different types with the ion concentrations in melted ice. Micro-Raman spectroscopy shows that Na2SO4 center dot 10H(2)O and MgSO4 center dot 11H(2)O are abundant in Holocene ice, while CaSO4 center dot 2H(2)O and other salts are abundant in LGM ice. Further, the number of CaSO4 center dot 2H(2)O particles is strongly correlated with the concentration of Ca2+ during Termination I. Taken together, the evidence strongly suggests that most of the Ca2+ exists as CaSO4 center dot 2H(2)O. The different compositions of microparticles from the Holocene and LGM can be explained by ion balance arguments.
  • Tsutomu Uchida, Seiichi Oshita, Masayuki Ohmori, Takuo Tsuno, Koichi Soejima, Satoshi Shinozaki, Yasuhisa Take, Koichi Mitsuda
    NANOSCALE RESEARCH LETTERS 6 1 X1 - 9 2011年 [査読有り][通常論文]
     
    Unique properties of micro- and nanobubbles (MNBs), such as a high adsorption of impurities on their surface, are difficult to verify because MNBs are too small to observe directly. We thus used a transmission electron microscope (TEM) with the freeze-fractured replica method to observe oxygen (O-2) MNBs in solutions. MNBs in pure water and in 1% NaCl solutions were spherical or oval. Their size distribution estimated from TEM images close to that of the original solution is measured by light-scattered methods. When we applied this technique to the observation of O-2 MNBs formed in the wastewater of a sewage plant, we found the characteristic features of spherical MNBs that adsorbed surrounding impurity particles on their surface.
  • The behavior of sulfate and chloride ions in ice sheets as a function of increasing depth
    Toshimitsu Sakurai, Shinichiro Horikawa, Yoshinori Iizuka, Takayuki Miyake, Tsutomu Uchida, Takeo Hondoh
    Physics and Chemistry of Ice 2010 [Y. Furukawa, G. Sazaki, T. Uchida, N. Watanabe (Eds)], Institute of Low Temperature Science, Hokkaido University press, Hokkaido, Japan 37 - 44 2011年 [査読有り][通常論文]
  • Toshimitsu Sakurai, Hiroshi Ohno, Shinichiro Horikawa, Yoshinori Iizuka, Tsutomu Uchida, Kazuomi Hirakawa, Takeo Hondoh
    JOURNAL OF GLACIOLOGY 57 206 1027 - 1032 2011年 [査読有り][通常論文]
     
    This study clarifies changes in the chemical forms of microparticles during Termination I, the period of drastic climate change between the Last Glacial Maximum (LGM) and the Holocene. We determine the chemical forms of individual water-soluble microparticles through micro-Raman spectroscopy and compare the relative frequencies of different types with the ion concentrations in melted ice. Micro-Raman spectroscopy shows that Na2SO4 center dot 10H(2)O and MgSO4 center dot 11H(2)O are abundant in Holocene ice, while CaSO4 center dot 2H(2)O and other salts are abundant in LGM ice. Further, the number of CaSO4 center dot 2H(2)O particles is strongly correlated with the concentration of Ca2+ during Termination I. Taken together, the evidence strongly suggests that most of the Ca2+ exists as CaSO4 center dot 2H(2)O. The different compositions of microparticles from the Holocene and LGM can be explained by ion balance arguments.
  • Tsutomu Uchida, Atsushi Miyamoto, Atsushi Shin'yama, Takeo Hondoh
    JOURNAL OF GLACIOLOGY 57 206 1017 - 1026 2011年 [査読有り][通常論文]
     
    Air-hydrate crystals store most of the ancient air contained in deep ice sheets. We carried out microscopic observations of air-hydrate crystals below 2000 m depth within the ice core from Dome Fuji, Antarctica, to obtain their number and size distributions. We found that the number density continuously decreased with depth, whereas the average size increased, in contrast to findings from shallower depths. In addition, the characteristic perturbations in both number density and average size distribution with climatic changes almost disappeared, although they are clearly observed in shallow cores. These results indicate that the air-hydrate crystals grow considerably in deeper parts of the ice sheet, and this growth is accompanied by the diffusion of air molecules in the ice. The permeation coefficient of the air molecules in the ice sheet was estimated from the geometric parameters of the air-hydrate distributions. This is the first practical evidence comparable to the previous model estimations. It allows us to evaluate the impacts of the air-molecule migration in the ice sheet on the paleoclimatic information recorded in the deep ice cores.
  • Tsutomu Uchida, Toshiki Shiga, Masafumi Nagayama, Kazutoshi Gohara
    ENERGIES 3 12 1960 - 1971 2010年12月 [査読有り][通常論文]
     
    Clathrate hydrates have recently received attention as novel storage and transportation materials for natural gases or hydrogen. These hydrates are treated as powders or particles, and moderate storage temperatures (around 253 K) are set for economic reasons. Thus, it is necessary to consider the sintering of hydrate particles for their easy handling because the hydrates have a framework similar to that of ice, even though their sintering would require guest molecules in addition to water molecules. We observed the sintering process of clathrate hydrates to estimate the rate of sintering. Spherical tetrahydrofuran (THF) hydrate particles were used in observations of sintering under a microscope equipped with a CCD camera and a time-lapse video recorder. We found that THF hydrate particles stored at temperatures below the equilibrium condition sintered like ice particles. The sintering part was confirmed to be not ice, but THF hydrate, by increasing the temperature above 273 K after each experiment. The sintering rate was lower than that of ice particles under the normal vapor condition at the same temperature. However, it became of the same order when the atmosphere of the sample was saturated with THF vapor. This indicates that the sintering rate of THF hydrate was controlled by the transportation of guest molecules through the vapor phase accompanied with water molecules.
  • D. Ito, H. Tamate, M. Nagayama, T. Uchida, S. N. Kudoh, K. Gohara
    NEUROSCIENCE 171 1 50 - 61 2010年11月 [査読有り][通常論文]
     
    To investigate the minimum neuron and neurite densities required for synchronized bursts, we cultured rat cortical neurons on planar multi-electrode arrays (MEAs) at five plating densities (2500, 1000, 500, 250, and 100 cells/mm(2)) using two culture media: Neuron Culture Medium and Dulbecco's Modified Eagle Medium supplemented with serum (DMEM/serum). Long-term recording of spontaneous electrical activity clarified that the cultures exhibiting synchronized bursts required an initial plating density of at least 250 cells/mm(2) for Neuron Culture Medium and 500 cells/mm(2) for DMEM/serum. Immediately after electrical recording, immunocytochemistry of microtubule-associated protein 2 (MAP2) and Neurofilament 200 kD (NF200) was performed directly on MEAs to investigate the actual densities of neurons and neurites forming the networks. Immunofluorescence observation revealed that the construction of complicated neuronal networks required the same initial plating density as for synchronized bursts, and that overly sparse cultures showed significant decreases of neurons and neurites. We also found that the final densities of surviving neurons at 1 month decreased greatly compared with the initial plating densities and became saturated in denser cultures. In addition, the area of neurites and the number of nuclei were saturated in denser cultures. By comparing both the results of electrophysiological recording and immunocytochemical observation, we revealed that there is a minimum threshold of neuron densities that must be met for the exhibition of synchronized bursts. Interestingly, these minimum densities of MAP2-positive final neurons did not differ between the two culture media; the density was approximately 50 neurons/mm(2). This value was obtained in the cultures with the initial plating densities of 250 cells/mm(2) for Neuron Culture Medium and 500 cells/mm(2) for DMEM/serum. (C) 2010 IBRO. Published by Elsevier Ltd. All rights reserved.
  • Riki Sakemoto, Hiroki Sakamoto, Kuniaki Shiraiwa, Ryo Ohmura, Tsutomu Uchida
    CRYSTAL GROWTH & DESIGN 10 3 1296 - 1300 2010年03月 [査読有り][通常論文]
     
    This paper reports visual observations of clathrate hydrate crystals growth at the interface of water/seawater and it guest substance to reveal the effect of salts on the crystal growth. Cyclopentane was used its the guest substance to form a structure II hydrate. Cyclopentane hydrate crystals grew along the interface of cyclopentane and seawater to form a polycrystalline layer covering the entire interface. We visually analyzed the individual crystals and classified the morphology of the hydrate crystals according to the subcooling (Delta T-sub) from the cyclopentane hydrate equilibrium temperature of atmospheric pressure. The results showed that the morphology of the individual cyclopentane hydrate crystals in water and seawater are qualitatively similar at similar subcooling. As a general trend, for Delta T-sub < 2.0 K the shape of the hydrate crystals is typically polygons, at Delta T-sub = 2.0-4.5 K, the shape changes to small polygons or slender polygons, and for Delta T-sub > 4.5 K, the crystals have triangular or swordlike shape.
  • 内田 努, 郷原 一寿
    Biol. Bull 218 1 6 - 14 2010年02月 [査読有り][通常論文]
     
    The pond snail Lymnaea stagnalis moves along the sides and bottom of an aquarium, but it can also glide upside down on its back below the water's surface. We have termed these two forms of locomotion "standard locomotion" and "upside-down gliding," respectively. Previous studies showed that standard locomotion is produced by both cilia activity on the foot and peristaltic contraction of the foot muscles. whereas upside-down gliding is mainly caused by cilia activity. The pedal A neurons are thought to receive excitatory octopaminergic input, Which ultimately results in increased cilia beating. However, the relationship between locomotory speed and the responses of these neurons to octopamine is not known. We thus examined the effects of both an agonist and an antagonist of octopamine receptors on locomotory speed and the firing rate of the pedal A neurons. We also examined. at the electron and light-microscopic levels, whether structural changes occur in cilia following the application of either an agonist or an antagonist of octopamine receptors to the central nervous system (CNS). We found that the application of an octopamine antagonist to the CNS increased the speed of both forms of locomotion, whereas application of octopamine increased only the firing rate of the pedal A neurons. Microscopic examination of the cilia proved that there were no chan-e in their morphology after application of octopamine me ligands. These data suggest that there is an unidentified octopaminergic neuronal network in the CNS whose activation reduces cilia movement and thus locomotory speed.
  • Yurie Miyamae, Mami Komuro, Aya Murata, Kanako Aono, Kaori Nishikata, Akira Kanazawa, Yutaka Fujito, Takumi Komatsu, Daisuke Ito, Takashi Abe, Masafumi Nagayama, Tsutomu Uchida, Kazutoshi Gohara, Jun Murakami, Ryo Kawai, Dai Hatakeyama, Ken Lukowiak, Etsuro Ito
    BIOLOGICAL BULLETIN 218 1 6 - 14 2010年02月 [査読有り][通常論文]
     
    The pond snail Lymnaea stagnalis moves along the sides and bottom of an aquarium, but it can also glide upside down on its back below the water's surface. We have termed these two forms of locomotion "standard locomotion" and "upside-down gliding," respectively. Previous studies showed that standard locomotion is produced by both cilia activity on the foot and peristaltic contraction of the foot muscles. whereas upside-down gliding is mainly caused by cilia activity. The pedal A neurons are thought to receive excitatory octopaminergic input, Which ultimately results in increased cilia beating. However, the relationship between locomotory speed and the responses of these neurons to octopamine is not known. We thus examined the effects of both an agonist and an antagonist of octopamine receptors on locomotory speed and the firing rate of the pedal A neurons. We also examined. at the electron and light-microscopic levels, whether structural changes occur in cilia following the application of either an agonist or an antagonist of octopamine receptors to the central nervous system (CNS). We found that the application of an octopamine antagonist to the CNS increased the speed of both forms of locomotion, whereas application of octopamine increased only the firing rate of the pedal A neurons. Microscopic examination of the cilia proved that there were no chan-e in their morphology after application of octopamine me ligands. These data suggest that there is an unidentified octopaminergic neuronal network in the CNS whose activation reduces cilia movement and thus locomotory speed.
  • Ice-shielding models for self-preservation of gas hydrates during temperature ramping test at atmospheric pressure
    T. Uchida, T. Sakurai, T. Hondoh
    Physics and Chemistry of Ice 2010 283 - 292 2010年 [査読有り][通常論文]
  • T. Sakurai, H. Ohno, S. Horikawa, Y. Iizuka, T. Uchida, T. Hondoh
    International Journal of Spectroscopy 2010 384956-1 - 384956-7 Hindawi Publishing Corporation 2010年 [査読有り][通常論文]
     
    We describe in detail our method of measuring the chemical forms of microparticles in polar ice samples through micro-Raman spectroscopy. The method is intended for solid ice samples, an important point because melting the ice can result in dissociation, contamination, and chemical reactions prior to or during a measurement. We demonstrate the technique of measuring the chemical forms of these microparticles and show that the reference spectra of those salts expected to be common in polar ice are unambiguously detected. From our measurements, Raman intensity of sulfate salts is relatively higher than insoluble dust due to the specific Raman scattering cross-section of chemical forms of microparticles in ice.
  • 宮村謙一郎, 永山昌史, 郷原一寿, 平敏夫, 清水恭子, 酒井雅人, 内田努
    低温生物工学会誌 56 2 111 - 117 低温生物工学会 2010年 [査読有り][通常論文]
     
    初代培養心筋細胞を凍結保存する技術開発を行い、融解した心筋細胞の機能を評価する手法を検討した。凍結保存した細胞の生存率と機能回復率を定量化するため、融解後の細胞に対し、トリパンブルー染色による細胞生存率、融解後7日間に亘る形態観察と同期拍動数測定を行い、コントロールとの比較を行った。培養最終日には免疫蛍光染色を行い、心筋細胞を確認した。冷却速度約-10℃/分、保存温度-80℃、保存期間7日間、DMSOを凍結保護剤として用いた新生子ラット心室由来初代培養心筋細胞の凍結保存において、未凍結の心筋細胞に比べて40〜50%程度が生存した。また、生存したものは未凍結の心筋細胞と同様に接着・伸展・拍動した。更にその拍動の機能も、最高拍動数回復率は70%以下となったが、未凍結の心筋細胞と同じように拍動した。それらの細胞はα-アクチニンを発現していることを免疫蛍光染色法で確認した。
  • Masafumi Nagayama, Kyoko Shimizu, Toshio Taira, Tsutomu Uchida, Kazutoshi Gohara
    FEBS LETTERS 584 1 86 - 92 2010年01月 [査読有り][通常論文]
     
    Time-lapse observation of adipocytes during catecholamine-induced lipolysis clearly shows that shrinking of existing lipid droplets (LDs) occurs in some adipocytes and that small LDs are newly developed in almost all cells. Immunofluorescence imaging reveals that activation and localization of hormone-sensitive lipase (HSL) on the surface of LDs, which are required for conferring maximal lipolysis, are necessary for the shrinking of the LDs. However, not all adipocytes in which phosphorylated HSL is localized on LDs exhibit shrinking of LDs. The simultaneous shrinking and development of LDs yield apparent fragmentation and dispersion of LDs in adipocytes stimulated with catecholamine. (C) 2009 Federation of European Biochemical Societies. Published by Elsevier B. V. All rights reserved.
  • Toshimitsu Sakurai, Hiroshi Ohno, F. Elif Genceli, Shinichirou Horikawa, Yoshinori Iizuka, Tsutomu Uchida, Takeo Hondoh
    JOURNAL OF GLACIOLOGY 56 199 837 - 842 2010年 [査読有り][通常論文]
     
    Using micro-Raman spectroscopy, we identified the chemical forms of methanesulfonate salt particles in reference samples of the Dome Fuji (Antarctica) ice core. We found only (CH3SO3)2Mg center dot nH(2)O among methanesulfonate salts, and this salt particle is most prevalent in the Last Glacial Maximum (LGM) ice. We suggest that during the LGM, (CH3SO3)(2)Mg center dot nH(2)O may have formed in the atmosphere through the chemical reaction of CH3SO3H with sea salts, but probably not in the firn and ice due to the neutralization of acid in LGM ice of inland Antarctica.
  • Tsutomu Uchida, Satoshi Takeya
    PHYSICAL CHEMISTRY CHEMICAL PHYSICS 12 45 15034 - 15039 2010年 [査読有り][通常論文]
     
    Powder X-ray diffraction (PXRD) measurements on rapid freezing samples of disaccharide (trehalose, sucrose, and maltose) solutions indicated that the crystalline phases in the sample were both hexagonal and cubic ice. The cubic ice existed at a higher ratio in the higher disaccharide concentration samples. The temperature ramping experiments revealed that the cubic ice was stable below 233 K, which was obviously higher than the temperature expected for a pure water system. The diffraction peak width of the hexagonal ice crystal was independent in the disaccharide concentrations. This indicated that the crystallite size of the hexagonal ice was more than several hundreds of nanometre, which coincided with the ice particle size previously observed in the freeze-fractured replica samples. The comparison of the present PXRD data with the replica observations by transmission electron microscope in an earlier study allows us to conclude that the cubic ice was formed at the grain boundary between the hexagonal ice and the coexisted non-crystalline disaccharide phase.
  • Tsutomu Uchida, Ryo Ohmura, Akira Hori
    JOURNAL OF PHYSICAL CHEMISTRY A 114 1 317 - 323 2010年01月 [査読有り][通常論文]
     
    Systematic observations of fluoromethane clathrate hydrates were carried out by Raman spectroscopy. The series of fluoromethanes, i.e., methane (CH4), fluoromethane (CH3F), difluoromethane (CH2F2), trifluoromethane (CHF3), and tetrafluoromethane (CF4) were used as standard guest molecules to investigate the vibration modes of the guest molecules in the hydrate phase, since all of these fluoromethanes are included in the same crystal structure and share similar functional groups. In this study, both the C-H and C-F vibration modes of the guest molecules were systematically collected and assigned each peak based on the density functional theory (DFT) calculations. The Raman peak table obtained by the DFT calculations was useful for assigning the Raman peaks measured by the experiments. The assignment of the Raman peaks of the C-H stretching mode of each fluoromethane hydrate coincided well with those estimated both experimentally and theoretically ill previous Studies. The empirical "loose cage-tight cage" model of the Raman peak shifts allowed us to estimate the unperturbed frequencies of the C-H symmetric stretching mode on CH3F molecules in the clathrate structure. Clathrate hydrates formed with deuterated water molecules indicated that the deuterium had little effect on the Raman spectra of the intramolecular vibration modes of the guest molecules within the experimental uncertainties.
  • OKUDAIRA Toshiki, NAGAYAMA Masafumi, GOHARA Kazutoshi, TAIRA Toshio, SHIMIZU Kyoko, SAKAI Masato, UCHIDA Tsutomu
    生物物理 50 2 S59  一般社団法人 日本生物物理学会 2010年
  • Nagayama Masafumi, Shimizu Kyoko, Taira Toshio, Uchida Tsutomu, Gohara Kazutoshi
    生物物理 50 2 S119  一般社団法人 日本生物物理学会 2010年
  • Toshimitsu Sakurai, Hiroshi Ohno, F. Elif Genceli, Shinichirou Horikawa, Yoshinori Iizuka, Tsutomu Uchida, Takeo Hondoh
    JOURNAL OF GLACIOLOGY 56 199 837 - 842 2010年 [査読有り][通常論文]
     
    Using micro-Raman spectroscopy, we identified the chemical forms of methanesulfonate salt particles in reference samples of the Dome Fuji (Antarctica) ice core. We found only (CH3SO3)2Mg center dot nH(2)O among methanesulfonate salts, and this salt particle is most prevalent in the Last Glacial Maximum (LGM) ice. We suggest that during the LGM, (CH3SO3)(2)Mg center dot nH(2)O may have formed in the atmosphere through the chemical reaction of CH3SO3H with sea salts, but probably not in the firn and ice due to the neutralization of acid in LGM ice of inland Antarctica.
  • 内田努, 大村亮, 堀彰
    アンサンブル 12 3 3 - 7 分子シミュレーション研究会 2010年 [査読無し][招待有り]
  • Tsutomu Uchida, Masafumi Nagayama, Kazutoshi Gohara
    JOURNAL OF CRYSTAL GROWTH 311 23-24 4747 - 4752 2009年12月 [査読有り][通常論文]
     
    The inhibitory effects of trehalose on ice crystal growth were discussed on the basis of the viscosity measurements of aqueous solutions via the dynamic light-scattering method. The temperature and concentration conditions of the solution were ranged between 268 and 343K and up to 50wt%, respectively, which were feasible for applying this novel technique and were useful in the indirect measurement of the macroscopic dynamic properties of the trehalose solutions. A comparison of the viscosity data with those reported in the literatures indicated the validity of this method for measuring the viscosity.The nonlinearity of the temperature and concentration dependences of the trehalose solutions suggested that two different hydrogen-bonding networks exist in the solutions within the investigated range. Dilute solutions of less than 10wt% of trehalose exhibited properties very similar to those of pure water. Higher concentration solutions had large viscosities with large temperature and concentration dependences. This was caused by the decrease in the free water in the solution and the development of hydrogen-bonding networks with hydrated trehalose clusters. Sucrose and maltose solutions had the same properties, so this would be the dominant inhibitory process of disaccharides on ice crystal growth.(C) 2009 Elsevier B.V. All rights reserved.
  • T. Shiga, K. Ishizuka, M. Nagayam, K. Gohara, T. Uchida
    雪氷 71 5 317 - 327 公益社団法人 日本雪氷学会 2009年 [査読有り][招待有り]
     
    透過型電子顕微鏡（TEM）を用いて，クラスレートハイドレートの実像および電子線回折像を得た． クラスレートハイドレート試料としては，テトラヒドロフラン（THF）ハイドレートを用い，試料水溶液を急冷または緩冷して観測用試料とした． クラスレートハイドレートは低圧下ではそれ自身不安定であり， また電子線照射に弱いと考えられる. TEM 中は10^-5Pa もの高真空であるため，試料を低温（ 約81K）に保つホルダを使用した．この装置による制約もあり，1つの実像について1枚の回折像しか得られなかった． そのため1枚の回折像からその観測している試料位置での結晶系と方位を決める手法を提案した．その手法の妥当性は，氷のTEM観測より確認した．実像の観察の結果，試料の形状は薄膜状あるいは100nm以下の大きさの微細粒状の物体が観測された． それぞれ回折パターンを観測すると， 薄膜状であっても単結晶と同じようなスポット状のパターンが得られた．解析の結果， ほとんどの頷域が六方晶氷であったが， 観測した試料の10％ 程度の割合で立方晶のII型クラスレートハイドレート結晶が確認された．
  • T. Uchida, M. Nagayama, K. Gohara
    J. Crystal Growth 311 23-24 4747 - 4752 2009年 [査読有り][通常論文]
  • 櫻井 俊光, 飯塚 芳徳, 谷 篤史, 内田 努, 本堂 武夫
    雪氷研究大会講演要旨集 2009 82 - 82 公益社団法人 日本雪氷学会／日本雪工学会 2009年
  • Suzuki Shotaro, Uchida Tsutomu, Nagayama Masafumi, Gohara Kazutoshi
    生物物理 49 S184  一般社団法人 日本生物物理学会 2009年
  • 志賀 俊樹, 永山 昌史, 郷原 一寿, 内田 努
    日本エネルギー学会大会講演要旨集 18 68 - 69 一般社団法人日本エネルギー学会 2009年 
    Recently, hydrates have been researched for new natural gas storage media. However, sintering phenomenon of hydrates has not been studied yet. If hydrate samples sinter each other, it will be harder to use. In this study, we made in-situ observation of sintering process on clathrate hydrate particles. We found the sintering rate of hydrate particles was smaller than ice.
  • Kanako Aono, Ayachika Fusada, Yorichika Fusada, Wataru Ishii, Yuji Kanaya, Mami Komuro, Kanae Matsui, Satoru Meguro, Ayumi Miyamae, Yurie Miyamae, Aya Murata, Shizuka Narita, Hiroe Nozaka, Wakana Saito, Ayumi Watanabe, Kaori Nishikata, Akira Kanazawa, Yutaka Fujito, Miki Yamagishi, Takashi Abe, Masafumi Nagayama, Tsutomu Uchida, Kazutoshi Gohara, Ken Lukowiak, Etsuro Ito
    BIOLOGICAL BULLETIN 215 3 272 - 279 2008年12月 [査読有り][通常論文]
     
    The pond snail Lymnaea stagnalis can often be observed moving upside down on its back just below the surface of the water. We have termed this form of movement "upside-down gliding." To elucidate the mechanism of this locomotion, we performed a series of experiments involving behavioral analyses and microscopic observations. These experiments were designed (1) to measure the speed of this locomotion; (2) to determine whether the mucus secreted from the foot of Lymnaea repels water, thereby allowing the snail to exploit the surface tension of the water for upside-down gliding; and (3) to observe the beating of foot cilia in this behavior. The beating of these cilia is thought to be the primary driving force for upside-down gliding. Our results demonstrate that upside-down gliding is an efficient active process involving the secretion of mucus that floats up to the water surface to serve as a substrate upon which cilia beat to cause locomotion at the underside of the water surface.
  • Kanako Aono, Ayachika Fusada, Yorichika Fusada, Wataru Ishii, Yuji Kanaya, Mami Komuro, Kanae Matsui, Satoru Meguro, Ayumi Miyamae, Yurie Miyamae, Aya Murata, Shizuka Narita, Hiroe Nozaka, Wakana Saito, Ayumi Watanabe, Kaori Nishikata, Akira Kanazawa, Yutaka Fujito, Miki Yamagishi, Takashi Abe, Masafumi Nagayama, Tsutomu Uchida, Kazutoshi Gohara, Ken Lukowiak, Etsuro Ito
    BIOLOGICAL BULLETIN 215 3 272 - 279 2008年12月 [査読有り][通常論文]
     
    The pond snail Lymnaea stagnalis can often be observed moving upside down on its back just below the surface of the water. We have termed this form of movement "upside-down gliding." To elucidate the mechanism of this locomotion, we performed a series of experiments involving behavioral analyses and microscopic observations. These experiments were designed (1) to measure the speed of this locomotion; (2) to determine whether the mucus secreted from the foot of Lymnaea repels water, thereby allowing the snail to exploit the surface tension of the water for upside-down gliding; and (3) to observe the beating of foot cilia in this behavior. The beating of these cilia is thought to be the primary driving force for upside-down gliding. Our results demonstrate that upside-down gliding is an efficient active process involving the secretion of mucus that floats up to the water surface to serve as a substrate upon which cilia beat to cause locomotion at the underside of the water surface.
  • Tsutomu Uchida, Ryo Ohmura, Akira Hori
    JOURNAL OF PHYSICAL CHEMISTRY C 112 12 4719 - 4724 2008年03月 [査読有り][通常論文]
     
    The five different structure-I hydrates were formed using the following five different guest substances: methane, fluoromethane, difluoromethane, trifluoromethane, and tetrafluoromethane, for the systematic investigation on the relation between the occupancy of the cages in the hydrates and the size of the guest molecules. The hydrate crystal samples were analyzed using Raman spectroscopy. The results revealed that the cage occupancy ratio between small and large cages of these guest molecules depended on their solvent accessible surface area (ASA). The critical ASA for the enclathration of small cages had a relatively narrow range: approximately 1.7 +/- 0.2 nm(2). It was found that clathrate hydrates formed with guest molecules having ASA in this critical range were expected to show high nonstoichiometric properties. The obtained relation between the cage occupancy ratio and ASA of guest molecules was generalized by comparison with the results on other structure-I hydrate-forming guest molecules reported in the literature.
  • Nagayama Masafumi, Shimizu Kyoko, Taira Toshio, Uchida Tsutomu, Gohara Kazutoshi
    生物物理 48 S50  一般社団法人 日本生物物理学会 2008年
  • Hiroki Tamate, Daisuke Ito, Masafumi Nagayama, Tsutomu Uchida, Kazutoshi Gohara
    NEUROSCIENCE RESEARCH 61 S164 - S164 2008年 [査読有り][通常論文]
  • Tsutomu Uchida, Satoshi Takeya, Yasushi Kamata, Ryo Ohmura, Hideo Narita
    INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH 46 14 5080 - 5087 2007年07月 [査読有り][通常論文]
     
    To reveal the preferential enclathration of various guest molecules of natural gas into the hydrate structure, systematically prepared hydrate samples from mixed gases such as ethane-propane (C2H6-C3H8), methane-ethane-propane (CH4-C2H6-C3H8), and methane-ethane-propane-iso-butane (CH4-C2H6-C3H8-i-C4H10) with powdered ice were analyzed by spectroscopic techniques. Powder X-ray diffraction analysis at approximately 150 K was used to determine the crystal structure of the sample. Microscopic Raman spectroscopy measured at approximately 120 K revealed the enclathration of guest molecules into various cages. Gas chromatographic analysis on feed gases and the gases retrieved from hydrate samples supported the mass balance estimations derived from the spectroscopic measurements. These results, together with previous studies, revealed the preferential cage-occupation rule of hydrocarbon molecules. The collection of the Raman spectra of the guest molecules in these hydrate samples and in various phases of pure systems are useful for natural sample analysis by this technique.
  • Tom Smith, John Ripmeester, Dendy Sloan, Tsutomu Uchida
    Data Science Journal 6 GH18 - GH24 2007年06月16日 [査読有り][通常論文]
     
    Laboratory Hydrate Data is one of the three constituent modules comprising the XML based Gas Hydrate Markup Language (a.k.a. GHML) schema, the others being Field Hydrate data by Löwner et al. and Hydrate Modeling by Wang et al. This module describes the characteristics of natural and synthetic gas hydrates as they pertain to data acquired via analysis within a laboratory environment. Such data include the preservation history (i.e.: technique, pressurization gas and pressure, etc), Macroscopic data (i.e.: water-sediment ratio, appearance, P-T behavior, etc) as well as that of the Microscopic realm.
  • D. Sloan, F. Kuznetsov, K. Lal, R. Loewner, Y. Makogon, G. Moridis, J. Ripmeester, Jean-Jacques Royer, T. Smith, B. Tohidi, T. Uchida, J. Wang, W. Wang, Y. Xiao
    Data Science Journal 6 GH1 - GH5 2007年06月16日 [査読有り][通常論文]
     
    Natural gas hydrates may contain more energy than all the combined other fossil fuels, causing hydrates to be a potentially vital aspect of both energy and climate change. This article is an overview of the motivation, history, and future of hydrate data management using a CODATA vehicle to connect international hydrate databases. The basis is an introduction to the Gas Hydrate Markup Language (GHML) to connect various hydrate databases. The accompanying four articles on laboratory hydrate data by Smith et al., on field hydrate data by Löwner et al., on hydrate modeling by Wang et al., and on construction of a Chinese gas hydrate system by Xiao et al. provide details of GHML in their respective areas.
  • Tsutomu Uchida, Masafumi Nagayama, Tamaki Shibayama, Kazutoshi Gohara
    JOURNAL OF CRYSTAL GROWTH 299 1 125 - 135 2007年02月 [査読有り][通常論文]
     
    Freezing of solutions including disaccharides (trehalose, sucrose, and maltose) has been investigated by microscopic observations of freeze-fractured replicas using FE-TEM. Three typical features were observed: the smooth surface considered as the ice crystal, fine particles as the precipitated disaccharide molecules, and remaining part as the glass state of the solution. The expanded observations of fine particle and its distribution investigations suggested that it was larger than 10 nm in size and averaged approximately 20-30 nm in diameter. The smallest particle was estimated to include several hundred disaccharide molecules. Based on systematic observations of trehalose solutions regarding concentrations and freezing rates, we concluded that ice crystal growth was inhibited by trehalose molecules. Since the ice crystal size reduced exponentially with increase in trehalose concentration, we could control ice crystal size formed in the frozen material. The growth inhibition of ice crystals with trehalose resulted both from a reduction in the free water in the solution due to a significant hydration effect and from an enhancement of nucleation of the ice crystals. It was confirmed that trehalose was more effective than the other disaccharide solutions examined for inhibiting the growth of ice crystals. (c) 2006 Elsevier B.V. All rights reserved.
  • 内田努, 本村寿太郎, 永山昌史, 郷原一寿
    低温生物工学会誌 53 2 161 - 166 低温生物工学会 2007年 [査読有り][通常論文]
     
    初代神経細胞を対象に、凍結速度の違いが細胞の蘇生率に及ぼす影響を検討した。さらに解凍した細泡を多電極基板上で培養することで、同時に多数の細胞の機能を簡便に調べる評価法を開発した。SDラット新生児の大脳皮質由来の初代神経細胞を用いた。培養用培地に凍結保護剤として5% dimethylsulfoxideを加え、-3℃/min〜-150℃/minの範囲で冷却速度を変化させた。1週間保存後急速解凍して培養し、冷却速度が遅いほど蘇生率が高かった。未凍結細胞と同等の自発発火が確認され、機能的にも保存されていた。
  • Masafumi Nagayama, Tsutomu Uchida, Kazutoshi Gohara
    JOURNAL OF LIPID RESEARCH 48 1 9 - 18 2007年01月 [査読有り][通常論文]
     
    By capturing time-lapse images of primary stromal-vascular cells (SVCs) derived from rat mesenteric adipose tissue, we revealed temporal and spatial variations of lipid droplets (LDs) in individual SVCs during adipocyte differentiation. Numerous small LDs (a few micrometers in diameter) appeared in the perinuclear region at an early stage of differentiation; subsequently, several LDs grew to more than 10 mm in diameter and occupied the cytoplasm. We have developed a method for the fluorescence staining of LDs in living adipocytes. Time-lapse observation of the stained cells at higher magnification showed that nascent LDs (several 100 nm in diameter) grew into small LDs while moving from lamellipodia to the perinuclear region. We also found that adipocytes are capable of division and that they evenly distribute the LDs between two daughter cells. Immunofluorescence observations of LD-associated proteins revealed that such cell divisions of SVCs occurred even after LDs were coated with perilipin, suggesting that the "final" cell division during adipocyte differentiation occurs considerably later than that characterized in 3T3-L1 cells. Our time-lapse observations have provided a detailed account of the morphological changes that SVCs undergo during adipocyte division and differentiation.
  • 内田 努, 本村 寿太郎, 宮村 謙一郎, 永山 昌史, 平 敏夫, 清水 恭子, 郷原 一寿
    日本雪氷学会全国大会講演予稿集 2007 53 - 53 公益社団法人 日本雪氷学会 2007年
  • 谷脇 伸也, 腰原 由公, 内田 努, 永山 昌史, 平 敏夫, 清水 恭子, 郷原 一寿
    生物物理 47 supplement S165  一般社団法人 日本生物物理学会 2007年 [査読無し]
  • 永山 昌史, 内田 努, 平 敏夫, 清水 恭子, 郷原 一寿
    生物物理 47 supplement S164  一般社団法人 日本生物物理学会 2007年 [査読無し]
  • 伊東 大輔, 安谷屋 英之, 玉手 宏基, 永山 昌史, 内田 努, 郷原 一寿
    生物物理 47 supplement S72  一般社団法人 日本生物物理学会 2007年 [査読無し]
  • T. Uchida, I. Y. Ikeda, R. Ohmura, S. Tsuda
    PHYSICS AND CHEMISTRY OF ICE 609 - 618 2007年 [査読有り][通常論文]
  • J. Motomura, T. Uchida, M. Nagayama, K. Gohara, T. Taira, K. Shimizu, M. Sakai
    Physics and Chemistry of Ice 409 - 416 2007年 [査読有り][通常論文]
  • 加美山 隆, 関 直樹, 岩佐 浩光, 内田 努, 海老沼 孝郎, 成田 英夫, 井川 直樹, 石井 慶信, Bennington, S. M, 鬼柳 善明
    Physica B; Condensed Matter 385-386 1 202 - 204 2006年11月 [査読有り][通常論文]
     
    メタンハイドレートの中性子非弾性散乱実験を行い、メタンハイドレートホストネットワーク中に内包されるメタン分子の挙動を解析した。その結果、メタンハイドレートに内包されているメタンは自由回転運動をしてるが、そのほかに10meV以下のエネルギー範囲に自由回転運動以外に起因する散乱ピークが観察された。これらのピークはメタンハイドレートの2種類のカゴ中でのメタンの局所的並進運動によるものであることを明らかにした。
  • S Takeya, A Hori, T Uchida, R Ohmura
    JOURNAL OF PHYSICAL CHEMISTRY B 110 26 12943 - 12947 2006年07月 [査読有り][通常論文]
     
    To gain a better understanding of the effects of guest molecules on the lattice and stability of type H hydrates, we performed powder X-ray diffraction (PXRD) measurements and semiempirical molecular orbital calculations. The unit cell parameters and cohesive energies of various type H hydrates that contain methane (CH4) were analyzed. PXRD measurements indicated that an increase in the large-molecule guest volume caused the unit cell volume to increase. It was also indicated that a large-molecule guest substance caused the a-axis-direction of the unit cell to increase with little decrease in the c-axis direction. Calculations of cohesive energy by means of a semiempirical molecular orbital method indicated that the functional group and configuration of large-molecule guest substances affects the stability of type H hydrates. It was concluded that the icosahedron (5(12)6(8)) cages do not easily increase in length along the c-axis direction when larger guest molecules are used to form the hydrate, but the 5(12)6(8) cage and the layer of dodecahedron (5(12)) cages can easily increase in length along the a-axis direction due to interactions of the guest-host molecule.
  • T. Uchida, R. Ohmura, I. Y. Ikeda, J. Nagao, S. Takeya, A. Hori
    Journal of Physical Chemistry B 110 10 4583 - 4588 2006年03月 [査読有り][通常論文]
     
    Phase equilibrium conditions and the crystallographic properties of structure-H type gas hydrates containing various amounts of methane (CH4), carbon dioxide (CO2) neohexane (2,2-dimethylbutane; NH), and liquid water were investigated. When the CH4 concentration was as high as approximately 70%, the phase equilibrium pressure of the structure-H hydrate, which included NH, was about 1 MPa lower at a given temperature than that of the structure-I hydrate with the same composition (except for a lack of NH). However, as the CO2 concentration increased, the pressure difference between the structures became smaller and, at CO2 concentrations below 50%, the phase equilibrium line for the structure-H hydrate crossed that for the structure I. This cross point occurred at a lower temperature at higher CO2 concentration. Extrapolating this relation between the cross point and the CO2 concentration to 100% CO2 suggests that the cross-point temperature would be far below 273.2 K. It is then difficult to form structure-H hydrates in the CO2-NH-liquid water system. To examine the structure, guest composition, and formation process of structure-H hydrates at various CH4-CO2 compositions, we used the methods of Raman spectroscopy, X-ray diffraction, and gas chromatography. Raman spectroscopic analyses indicated that the CH4 molecules were found to occupy both 5(12) and 4(3)5(3)6(3) cages, but they preferably occupied only the 5(12) cages. On the other hand, the C02 molecules appeared to be trapped only in the 4(3)5(6)6(3) cages. Thus, the C02 molecules aided the formation of structure-H hydrates even though they reduced the stability of that structure. This encaged condition of guest molecules was also compared with the theoretical calculations. In the batch-type reactor, this process may cause the fractionation of the remaining vapor composition in the opposite sense as that for CH4-CO2 hydrate (structure-I), and thus may result in an alternating formation of structure-H hydrates and structure-I in the same batch-type reactor.
  • R Ohmura, S Takeya, T Maekawa, T Uchida
    JOURNAL OF CHEMICAL AND ENGINEERING DATA 51 1 161 - 163 2006年01月 [査読有り][通常論文]
     
    The temperature and pressure conditions for vapor + liquid + liquid + hydrate four-phase equilibrium in the krypton + 2,2-dimethylbutane + water system have been measured over the temperatures from 273.5 K to 285.6 K. The four-phase equilibrium pressure at a given temperature is lower by 1 MPa to 2.1 MPa than the corresponding equilibrium pressure of structure-II hydrate-forming krypton + water system without 2,2-dimethylbutane. This reduction in the equilibrium pressure due to the addition of 2,2-dimethylbutane suggests the formation of a structure-H hydrate containing krypton as a small-molecule guest and 2,2-dimethylbutane as a large-molecule guest substance. The formation of structure-H hydrate has been confirmed by means of X-ray diffraction measurement.
  • 内田 努, 永山 昌史, 柴山 環樹, 郷原 一寿
    日本雪氷学会全国大会講演予稿集 2006 61 - 61 公益社団法人 日本雪氷学会 2006年
  • Sekimoto Junji, Nagayama Masafumi, Uchida Tsutomu, Shimizu Kyoko, Taira Toshio, Gohara Kazutoshi
    生物物理 46 2 S371  一般社団法人 日本生物物理学会 2006年
  • Nagayama Masafumi, Uchida Tsutomu, Taira Toshio, Shimizu Kyoko, Sakai Masato, Gohara Kazutoshi
    生物物理 46 2 S261  一般社団法人 日本生物物理学会 2006年
  • H Oyama, W Shimada, T Ebinuma, Y Kamata, S Takeya, T Uchida, J Nagao, H Narita
    FLUID PHASE EQUILIBRIA 234 1-2 131 - 135 2005年07月 [査読有り][通常論文]
     
    Tetra-n-butyl ammonium bromide (TBAB) is a tetra-alkylammonium salt, that forms two types of semiclathrate hydrate. At atmospheric pressure, the melting points are between room temperature and freezing point of water. There are some useful applications of the semiclathrate, for example using as a heat transport medium and gas separator, but there are little knowledge about TBAB hydrates characteristics. In this paper, some thermal properties of TBAB semiclathrate hydrate are reported. We determined the phase diagram of semiclathrate hydrate nucleation under the condition of atmospheric pressure, latent and specific heats capacity of TBAB semiclathrate hydrate. From the phase diagram, the congruent melting points of two TBAB hydrates were determined. Using above results, we obtained the hydration numbers of two type TBAB hydrates. (c) 2005 Elsevier B.V. All rights reserved.
  • Masafumi Nagayama, Tsutomu Uchida, Toshio Taira, Takuya Hoshi, Kyoko Shimizu, Masato Sakai, Kazutoshi Gohara
    CELL STRUCTURE AND FUNCTION 30 34 - 34 2005年06月 [査読有り][通常論文]
  • R Ohmura, S Matsuda, T Uchida, T Ebinuma, H Narita
    JOURNAL OF CHEMICAL AND ENGINEERING DATA 50 3 993 - 996 2005年05月 [査読有り][通常論文]
     
    Four-phase (ice + structure-H hydrate + large-molecule guest substance liquid + methane-rich vapor) equilibrium pressure-temperature conditions were measured at temperatures from 252 K to 272 K in systems of water + methane + LMGS, where LMGS is a large-molecule guest substance for a structure-H hydrate. The tested LMGSs were 2,2-dimethylbutane (neohexane), methylcyclohexane, and tert-butyl methyl ether. The results obtained in the 2,2-dimethylbutane system agree with the corresponding data reported by Makogon et al., which were the only data set on the structure-H hydrate phase equilibrium at temperatures below the freezing point of water. Among the three systems studied, the lowest equilibrium pressure at a given temperature was observed in the 2,2-dimethylbutane system, and the highest, in the tert-butyl methyl ether system.
  • R Ohmura, S Matsuda, T Uchida, T Ebinuma, H Narita
    CRYSTAL GROWTH & DESIGN 5 3 953 - 957 2005年05月 [査読有り][通常論文]
     
    This paper reports on a visual study of formation and growth of clathrate hydrate crystals in liquid water saturated (prior to hydrate formation) and in contact with methane gas under the pressure of 6-10 MPa at a temperature of 273.5 K. Irrespective of the pressure set in the experimental system, in most of the experimental runs we observed that a hydrate film first formed to intervene between methane gas and liquid water, and then hydrate crystals grew in liquid water from the hydrate film. Distinct variations in the morphology of hydrate crystals grown in liquid water were observed depending on the pressure. At pressures of 6-8 MPa, hydrate crystals with skeletal, columnar morphology were observed. At the pressure of 10 MPa, the skeletal, columnar crystals were replaced by dendritic crystals. The dependency of the morphology on the degree of driving force for mass-transfer-controlled hydrate-crystal growth is discussed, comparing the present observations with those reported in the literature. Another category of hydrate formation and growth was observed in some experimental runs. The hydrate crystals first formed at the inner surface of the test cell in contact with liquid water instead of the methane-water interface. These crystals floated up to the methane-water interface, where they became a polycrystalline hydrate film, and continued to grow in liquid water.
  • T Uchida, IY Ikeda, S Takeya, Y Kamata, R Ohmura, J Nagao, OY Zatsepina, BA Buffett
    CHEMPHYSCHEM 6 4 646 - 654 2005年04月 [査読有り][通常論文]
     
    The formation of CH4-CO2 mixed gas hydrates was observed by measuring the change of vapor-phase composition using gas chromatography and Roman spectroscopy. Preferential consumption of carbon dioxide molecules was found during hydrate formation, which agreed well with thermodynamic calculations. Both Roman spectroscopic analysis and the thermodynamic calculation indicated that the kinetics of this mixed gas hydrate system was controlled by the competition of both molecules to be enclathrated into the hydrate cages. However, the methane molecules were preferentially crystallized in the early stages of hydrate formation when the initial methane concentration was much less than that of carbon dioxide. According to the Raman, spectra, pure methane hydrates first formed under this condition. This unique phenomenon suggested that methane molecules play important roles in the hydrate formation process. These mixed gas hydrates were stored at atmospheric pressure and 190 K for over two months to examine the stability of the encaged gases. During storage, CO2 was preferentially released. According to our thermodynamic analysis, this CO2 release was due to the instability of CO, in the hydrate structure under the storage conditions.
  • W Shimada, S Takeya, Y Kamata, T Uchida, J Nagao, T Ebinuma, H Narita
    JOURNAL OF PHYSICAL CHEMISTRY B 109 12 5802 - 5807 2005年03月 [査読有り][通常論文]
     
    We used a confocal scanning microscope to observe growth and texture change of ice due to the dissociation of methane gas clathrate hydrate (CH4 hydrate). The experiments were done under CH4 gas atmospheric pressure and isothermal conditions between 170 and 268 K. Above 193 K, the dissociation of CH4 hydrate resulted in many small Ice particles that covered the hydrate surface. These ice particles had roughly the same shape and density between 193 and 210 K. In contrast, above 230 K the ice particles developed into a sheet of ice that covered the hydrate surface. Moreover, the measured release of CH4 gas decreased when the sheet of ice formed at the surface of the hydrate. These findings can explain the anomalous preservation behaviour of CH4 hydrate; that is, the known increase of storage stability of CH4 hydrate above 240 K is likely related to the formation of the ice that we observed in the experiments.
  • S Takeya, T Uchida, J Nagao, R Ohmura, W Shimada, Y Kamata, T Ebinuma, H Narita
    CHEMICAL ENGINEERING SCIENCE 60 5 1383 - 1387 2005年03月 [査読有り][通常論文]
     
    In this study, we used time-resolved, energy-dispersive X-ray diffraction to study the dissociation of methane hydrate of various particle sizes into hexagonal ice and methane gas. The samples of polycrystalline methane hydrate were warmed from 135 to 263 K by slow warming at a rate of 1 K/min under atmospheric pressure. For particle sizes below about 250 mum, all the hydrates dissociated by about 210K. However, larger particle sizes had a high temperature regime in which the hydrate fraction decreased very little with increased temperature. For particle sizes of 1000-1400mum, 20% of the hydrate remained even at 263K. This apparent ability to retain hydrate at high temperatures is consistent with the oft-studied self-preservation effect in which the hydrate is encased by ice that greatly hinders the dissociation process due to methane gas diffusion through the ice. Confocal scanning microscope images of methane hydrate surface after partial dissociation revealed small grains of ice covering the CH4 hydrate surface. These results indicate that, for equal volumes of hydrate. larger hydrate particles can retain more CH4 gas at a given temperature than small particles. (C) 2004 Elsevier Ltd. All rights reserved.
  • T. Uchida, T. Uchida, A. Kato, H. Sasaki, F. Kono, S. Takeya
    Gedogical Survey of Canada GSC Bulletin 585 105  2005年 [査読有り][通常論文]
     
    T. Uchida, T. Uchida, A. Kato, H. Sasaki, F. Kono, S. Takeya
    “Physical properties of natural gas hydrate and associated gas-hydrate-baring sediments in the JAPEX/JNOC/GSC et al. Mallik 5L-38 gas hydrate production research well”
    Gedogical Survey of Canada GSC Bulletin, Bulletin 585, 105, 2005*
  • S Takeya, T Uchida, Y Kamata, J Nagao, M Kida, H Minami, H Sakagami, A Hachikubo, N Takahashi, H Shoji, O Khlystov, M Grachev, Soloviev, V
    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 44 42 6928 - 6931 2005年 [査読有り][通常論文]
  • 本村 寿太郎, 内田 努, 永山 昌史, 郷原 一寿, 平 敏夫, 清水 恭子, 酒井 雅人
    生物物理 45 supplement S91 - S91 一般社団法人 日本生物物理学会 2005年 [査読無し]
  • 内田 努, 永山 昌史, 柴山 環樹, 郷原 一寿
    生物物理 45 supplement S240  一般社団法人 日本生物物理学会 2005年 [査読無し]
  • R Ohmura, S Takeya, T Uchida, T Ebinuma
    INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH 43 16 4964 - 4966 2004年08月 [査読有り][通常論文]
     
    This paper reports confirmation of structure II hydrate formation in a methane-2-propanol-water system, which was previously suggested by Ostergaard et al. (Ind. Eng. Chem. Res. 2002, 41, 2064-2068) based on a comparison of the phase-equilibrium data with corresponding statistical-thermodynamics predictions. A hydrate crystal sample was prepared with a 16.4 mass % aqueous solution of 2-propanol pressurized with methane and then subjected to a powder X-ray diffraction analysis. The X-ray diffraction pattern thus obtained from the sample indicated that the crystallographic structure of the hydrate was structure II. The pressure-temperature data for aqueous liquid-hydrate-methane-rich vapor three-phase equilibrium in a temperature range from T = 273 to 283 K are also reported.
  • DH Smith, K Seshadri, T Uchida, JW Wilder
    AICHE JOURNAL 50 7 1589 - 1598 2004年07月 [査読有り][通常論文]
     
    Equilibrium pressure for the dissociation of methane, propane, or carbon dioxide hydrates confined in porous glass pores of nominal 15 nut radii were measured over a wide temperature range. A previously presented model is used to determine the pore radius involved at each temperature. Based on these results, pore volume distributions were reconstructed and compared with distributions obtained from nitrogen desorption isotherms. The analysis of the reported data indicate that for all three hydrates, nearly all of the sorbed water was converted to hydrate, but the amount of water taken lip by the porous glass was less than that expected from nitrogen desorption studies. When propane was used to form hydrate, the pores not occupied by hydrate were involved in propane vapor-liquid equilibria. (C) 2004 American Institute of Chemical Engineers AIChE J, 50: 1589-1598, 2004
  • R Ohmura, S Takeya, T Uchida, IY Ikeda, T Ebinuma, H Narita
    FLUID PHASE EQUILIBRIA 221 1-2 151 - 156 2004年07月 [査読有り][通常論文]
     
    Clathrate hydrate formation in the system methane + 3-methyl-1-butanol + water is demonstrated. The data of four-phase-equilibria for methane + 3-methyl-1-butanol + hydrate + water equilibria are determined in the temperature range of 273-282 K. The equilibrium pressures at temperatures below 279 K are lower, by 0.4 MPa at most, than those of structure I hydrate formed in the methane + water system without 3-methly-1-butanol, suggesting the formation of a hydrate different from structure I methane hydrate. Conversely, at temperatures above 279 K, the equilibrium pressures are higher by 0.2 MPa than those of the methane structure I hydrate, suggesting the thermodynamically inhibited formation of structure I methane hydrate. To confirm the crystallographic structures of the hydrates, X-ray diffraction and Raman-spectroscopy measurements were performed with hydrate crystal samples prepared at two conditions: at 274.0 K and 2.55 MPa, and at 279.5 K and 6.30 MPa. The measurements revealed a structure II hydrate formation at the lower temperature, contrary to the expectation of the structure H hydrate formation. The hydrate formed at the higher temperature was determined to be of structure I. (C) 2004 Elsevier B.V. All rights reserved.
  • T. Kamiyama, Y. Kiyanagi, T. Horikawa, H. Iwasa, T. Uchida, T. Ebinuma, H. Narita, S. M. Bennington
    PHYSICA B-CONDENSED MATTER 350 1-3 E395 - E398 2004年07月 [査読有り][通常論文]
     
    Methane hydrate is a possible candidate material for use as a cold neutron moderator in pulsed neutron sources. Our aim was to perform inelastic neutron scattering measurements with sufficient range in energy and momentum to create a scattering kernel to simulate its behavior as a moderator material. Measurements were made on samples of D2O-CH4 and H2O-CH4 at 12K covering a range up to 500meV and 28 angstrom(-1). These data clearly shows the almost free recoil of the CH4 rotational and vibrational modes and confirms that the dynamics of the ice and methane are largely decoupled on the energy scales that we are studying. From these initial measurements we can conclude that methane hydrate will be a good moderator over a wide range of neutron energies. We are now able to produce models of sufficient quality to create scattering kernels for the Monte-Carlo simulation codes that are used to design neutron sources. (C) 2004 Elsevier B.V. All rights reserved.
  • T Uchida, S Takeya, EM Chuvilin, R Ohmura, J Nagao, VS Yakushev, VA Istomin, H Minagawa, T Ebinuma, H Narita
    JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH 109 B5 B05206  2004年05月 [査読有り][通常論文]
     
    Decomposition conditions of methane hydrates in sediments were measured during formation-decomposition cycles. As test sediments, we used silica sand, sandstone, and clays (kaoline and bentonite), which are typical natural materials known as hydrate bearing sediments, and the range of samples cover a range of water saturating abilities. To better understand the results, we also used uniformly sized glass beads. Pore effects on decomposition of these materials were investigated by analyzing the pore-space distributions of the materials and by varying the initial water content of the samples. The results obtained for sand and sandstone samples indicated that the final decomposition temperatures were shifted lower than those for bulk hydrates at the same pressure. Temperature shifts were more negative for smaller initial water contents with the maximum shift being approximately -0.5 K. The results were consistent with those measured for glass beads with nearly the same particle size. For kaoline clays, the shift was at most -1.5 K. We conclude that the decomposition conditions are mainly affected by the pore sizes. The surface textures and mineral components had less influence on the results. We confirmed that glass beads mimic the effect of sediments for sand, sandstone, and kaoline clays, which have little to no swelling when put in contact with water. On the other hand, for bentonite particles, the results indicated that methane hydrates formed not only between the particles but also in the interlayers. A thermodynamic promoting effect was found for dilute bentonite solutions, although the positive decomposition-temperature shift was at most +0.5 K.
  • T Uchida, M Moriwaki, S Takeya, IY Ikeda, R Ohmura, J Nagao, H Minagawa, T Ebinuma, H Narita, K Gohara, S Mae
    AICHE JOURNAL 50 2 518 - 523 2004年02月 [査読有り][通常論文]
     
    Vapor compositions of methane and propane mixed gas in a batch-type reactor were measured by gas chromatography during hydrate crystallization at 274 K with molar ratios of propane below 10 vol %. The volume ratio of propane in the vapor decreased as the hydrate crystallization progressed. When the initial propane concentration was between 4 and 8 vol %, rapid gas consumption occurred for about I h, causing an initial pressure drop, and after a temporary stabilization of the pressure, a second pressure drop occurred; that is, hydrate crystallization occurred in two steps. X-Ray diffraction and Raman spectroscopic analyses on samples taken from the reactor during each step revealed that the structure II methane-propane mixed gas hydrates crystallized in the first step, and structure I methane hydrates in the second step. This process was observed only when the partial pressure of methane was above the equilibrium pressure of methane hydrate at the end of the first step. (C) 2004 American Institute of Chemical Engineers.
  • Ryo Ohmura, Wataru Shimada, Tsutomu Uchida, Yasuhiko H. Mori, Satoshi Takeya, Jiro Nagao, Hideki Minagawa, Takao Ebinuma, Hideo Narita
    Philosophical Magazine 84 1 1 - 16 2004年01月01日 [査読有り][通常論文]
     
    This paper reports on our interpretation of our visual observations of the variations in macroscopic morphology of hydrate crystals growing in liquid water saturated with a guest substance prior to the hydrate formation. The observations were made in a high-pressure cell charged with liquid water and gaseous CO2. They revealed distinct variations in the morphology of hydrate crystals depending on the system subcooling δTsub, the temperature deficiency inside the cell from the triple CO 2-hydrate-water equilibrium temperature under a given pressure. When δTsub ≲ 3K, a hydrate film first grew along the CO 2-water interface then hydrate crystals with dendritic morphology grew in large numbers into the liquid-water phase from that hydrate film. When δTsub ≲ 2K, the dendritic crystals were replaced by skeletal or polyhedral crystals. We present a non-dimensional index for such variations in hydrate crystal morphology. This is based on the idea that this morphology depends on the growth rate of hydrate crystals, and their growth rate is controlled by the mass transfer of the hydrate-guest substance (CO 2 in the present experiments), dissolved in the bulk of liquid water, to the hydrate crystal surfaces. The morphology variations observed in the present and previous studies are related to this index.
  • Y Kamata, H Oyama, W Shimada, T Ebinuma, S Takeya, T Uchida, J Nagao, H Narita
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS 43 1 362 - 365 2004年01月 [査読有り][通常論文]
     
    We used tetra-n-butyl ammonium bromide semi-clathrate hydrate, hereafter TBAB hydrate, as a tool for separating gases from binary mixed gas systems of methane+ethane, methane+propane, methane+hydrogen sulfide, methane+nitrogen, and carbon dioxide+hydrogen sulfide by growing the hydrate from 10 wt% TBAB aqueous solutions in a pressure vessel. TBAB hydrate has empty dodecahedral cages in the pure system. We found that small molecules such as methane, nitrogen, and hydrogen sulfide were selectively encaged during TBAB hydrate formation, probably because the dodecahedral cages are too small to incorporate large molecules such as ethane and propane. Furthermore, hydrogen sulfide was more readily encaged compared to the other small molecules; we argue that this was due to the very high solubility of hydrogen sulfide in water. We propose that gases with small molecular size and high solubility in water can be effectively separated using TBAB semi-clathrate hydrate.
  • 永山 昌史, 内田 努, 平 敏夫, 星 卓也, 郷原 一寿
    生物物理 44 supplement S63 - S63 一般社団法人 日本生物物理学会 2004年 [査読無し]
  • R Ohmura, W Shimada, T Uchida, YH Mori, S Takeya, J Nagao, H Minagawa, T Ebinuma, H Naritay
    PHILOSOPHICAL MAGAZINE 84 1 1 - 16 2004年01月 [査読有り][通常論文]
     
    This paper reports on our interpretation of our visual observations of the variations in macroscopic morphology of hydrate crystals growing in liquid water saturated with a guest substance prior to the hydrate formation. The observations were made in a high-pressure cell charged with liquid water and gaseous CO2. They revealed distinct variations in the morphology of hydrate crystals depending on the system subcooling DeltaT(sub), the temperature deficiency inside the cell from the triple CO2-hydrate-water equilibrium temperature under a given pressure. When DeltaT(sub)greater than or similar to3K, a hydrate film first grew along the CO2-water interface; then hydrate crystals with dendritic morphology grew in large numbers into the liquid-water phase from that hydrate film. When DeltaT(sub)less than or similar to2K, the dendritic crystals were replaced by skeletal or polyhedral crystals. We present a non-dimensional index for such variations in hydrate crystal morphology. This is based on the idea that this morphology depends on the growth rate of hydrate crystals, and their growth rate is controlled by the mass transfer of the hydrate guest substance (CO2 in the present experiments), dissolved in the bulk of liquid water, to the hydrate crystal surfaces. The morphology variations observed in the present and previous studies are related to this index.
  • R Ohmura, T Uchida, S Takeya, J Nagao, H Minagawa, T Ebinuma, H Narita
    JOURNAL OF CHEMICAL THERMODYNAMICS 35 12 2045 - 2054 2003年12月 [査読有り][通常論文]
     
    The present study experimentally demonstrated clathrate hydrate formation in the systems of (methane + water + each of the three methylcyclohexanone isomers, i.e., 2-methylcyclohexanone, 3-methylcyclohexanone, and 4-methylcyclohexanone) and measured the first data of the quadruple (water rich liquid + hydrate + methylcyclohexanone rich liquid + methane rich vapor) equilibrium pressure and temperature conditions in these systems over the temperatures from T = 273 K to T = 281 K. In the three systems with methylcyclohexanone, the measured equilibrium pressure at each given temperature is similar to1.3 MPa lower than that in a structure-I hydrate forming (methane + water) system without any methylcyclohexanone, which suggests the formation of structure-H hydrates with methylcyclohexanones as large-molecule guest substances. Among the three systems, 3-methyleyclohexanone provides the highest equilibrium pressure, and 2-methylcyclohexanone, the lowest. (C) 2003 Elsevier Ltd. All rights reserved.
  • R Ohmura, T Uchida, S Takeya, J Nagao, H Minagawa, T Ebinuma, H Narita
    JOURNAL OF CHEMICAL AND ENGINEERING DATA 48 5 1337 - 1340 2003年09月 [査読有り][通常論文]
     
    The pressure and temperature conditions for the four-phase equilibrium in systems that include structure-H hydrate, methane gas, liquid water, and either 3,3-dimethyl-2-butanone (pinacolone) or 3,3-dimethyl-2-butanol (pinaeolyl alcohol) liquid have been measured over the temperature range T = 273 K to T = 281 K. At a given temperature, the equilibrium pressures of the systems with pinacolone and pinacolyl alcohol are lower by 1.8 MPa and 1.3 MPa, respectively, than those of the structure-I hydrate-forming methane + water system. The equilibrium pressures in the system with pinacolone are roughly equal to those for the system with neohexane, whereas the pressures for the system with pinacolyl alcohol are higher by 0.5 MPa than those with neohexane. This suggests that the hydroxyl functional groups on the large-molecule guest substances can increase the equilibrium pressure in structure-H hydrate-forming systems, whereas the ketone groups can have little influence on the pressure.
  • T Uchida, R Ohmura, J Nagao, S Takeya, T Ebinuma, H Narita
    JOURNAL OF CHEMICAL AND ENGINEERING DATA 48 5 1225 - 1229 2003年09月 [査読有り][通常論文]
     
    The viscosity of water containing dissolved CO2 at pressures up to 5 MPa was measured by a new method based on dynamic light scattering. The accuracy of this method was checked by measuring the temperature dependence of the viscosity of pure water at pressures up to 5 MPa and comparing the results to values in the literature that were determined by other methods. The discrepancy of the measured viscosity of water from the literature was +/-6%, which roughly equals the composite uncertainty of this method. The effect of dissolved CO2 on the viscosity was determined as functions of time, temperature, and pressure. The results indicated that the viscosity of the solution increased with increasing CO2 concentration. High viscosities were observed under conditions in which CO2 hydrates can form.
  • W Shimada, T Ebinuma, H Oyama, Y Kamata, S Takeya, T Uchida, J Nagao, H Narita
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS 42 2A L129 - L131 2003年02月 [査読有り][通常論文]
     
    Tetra-n-butyl ammonium bromide (TBAB) forms a semi-clathrate hydrate crystal with water molecules even under atmospheric pressure. We found that TBAB hydrate could encage methane molecules in mixtures of methane and propane or methane and ethane. Our preliminary result of single-crystal analysis using X-ray shows that TBAB hydrate has empty cages, all of which are small, dodecahedral cages. Therefore, TBAB hydrate crystals can be used to separate small gas molecules which fit in these dodecahedral cages. We concluded that these empty unisized cages of TBAB hydrate crystals function as a sieve for gas molecules.
  • T Uchida, R Okabe, K Gohara, S Mae, Y Seo, H Lee, S Takeya, J Nagao, T Ebinuma, H Narita
    CANADIAN JOURNAL OF PHYSICS 81 1-2 359 - 366 2003年01月 [査読有り][通常論文]
     
    To reveal the hydrophobic hydration process of methane molecules dissolved in water, Raman spectra of dissolved methane (CH4) in water were measured under various conditions. The conditions include water saturated with CH4 gas, water-CH4 solution with CH4 hydrate crystals in equilibrium, and also during hydrate decomposition. The symmetric C-H stretching mode of the CH4 molecule in water is a single peak at 2910 cm(-1) with a half-width of approximately 5 cm(-1). These results indicate that the size of the space for the CH4 molecules, called the hydration shell, is between the large and small cages of the hydrate crystal, but it has a broad size distribution. To better understand the CH4-molecule vibrations, its spectrum in water was compared with its spectra in liquid carbon dioxide (CO2) and in liquid ethane (C2H6). These spectra were very similar to those observed in water, except that the peak widths were sharper than those in water. This suggests that the broadening of the shell-size distribution is due to the way the CH4 molecules affect the hydration shell. On the other hand, when the system included hydrate crystals, a double CH4 peak arose due to structure in the aqueous solution near the crystal surface. This indicates that a cage-like structure can exist in the water phase. Compared with the decomposition experiment, the cage-like structure is likely due to the presence of the bulk hydrate crystal and is different from the hydration shell for the dissolved CH4 molecules.
  • T Uchida, R Okabe, K Gohara, S Mae, Y Seo, H Lee, S Takeya, J Nagao, T Ebinuma, H Narita
    CANADIAN JOURNAL OF PHYSICS 81 1-2 359 - 366 2003年01月 [査読有り][通常論文]
     
    To reveal the hydrophobic hydration process of methane molecules dissolved in water, Raman spectra of dissolved methane (CH4) in water were measured under various conditions. The conditions include water saturated with CH4 gas, water-CH4 solution with CH4 hydrate crystals in equilibrium, and also during hydrate decomposition. The symmetric C-H stretching mode of the CH4 molecule in water is a single peak at 2910 cm(-1) with a half-width of approximately 5 cm(-1). These results indicate that the size of the space for the CH4 molecules, called the hydration shell, is between the large and small cages of the hydrate crystal, but it has a broad size distribution. To better understand the CH4-molecule vibrations, its spectrum in water was compared with its spectra in liquid carbon dioxide (CO2) and in liquid ethane (C2H6). These spectra were very similar to those observed in water, except that the peak widths were sharper than those in water. This suggests that the broadening of the shell-size distribution is due to the way the CH4 molecules affect the hydration shell. On the other hand, when the system included hydrate crystals, a double CH4 peak arose due to structure in the aqueous solution near the crystal surface. This indicates that a cage-like structure can exist in the water phase. Compared with the decomposition experiment, the cage-like structure is likely due to the presence of the bulk hydrate crystal and is different from the hydration shell for the dissolved CH4 molecules.
  • H Oyama, T Ebinuma, W Shimada, S Takeya, J Nagao, T Uchida, H Narita
    CANADIAN JOURNAL OF PHYSICS 81 1-2 485 - 492 2003年01月 [査読有り][通常論文]
     
    We measured the viscosities and infrared (IR) spectra before and after hydrate nucleation. During the induction period, the viscosity increases and the infrared spectrum shifts to higher energy. After nucleation, the viscosity decreases abruptly, and the peak positions in the IR spectrum change to the small wave-number side. These results indicate that water acts as a precursor to hydrate nucleation.
  • The Structure Transition of Methane + Ethane Hydrate
    Takeya, S, Kamata, Y, Uchida, T, Nagao, J, Hori, A, Hondoh, T, Ebinuma, T, Narita, H
    Can. J. Phys. 81 1-2 479 - 484 2003年 [査読有り][通常論文]
  • EM Chuvilin, T Ebinuma, Y Kamata, T Uchida, S Takeya, J Nagao, H Narita
    CANADIAN JOURNAL OF PHYSICS 81 1-2 343 - 350 2003年01月 [査読有り][通常論文]
     
    Experimental results on hydrate- and ice-formation conditions in the pores of sandy sediments that have undergone temperature cycles are presented. Thermodynamic parameters of gas hydrate and ice formation in porous space were determined for CH4 and CO2 saturated sandy sediments. The experiments indicate that temperature and freezing cycles affect the thermodynamics of hydrate and water-ice in gas-saturated sediments. Temperature cycles increased the hydrate accumulation in the pore space of sediments and reduce the freezing temperature of the remaining pore water.
  • 竹谷 敏, 長尾 二郎, 皆川 秀紀, 内田 努, 大村 亮, 鎌田 慈, 海老沼 孝郎, 成田 英夫
    日本エネルギー学会大会講演要旨集 12 82 - 83 一般社団法人日本エネルギー学会 2003年
  • 皆川 秀紀, 大山 裕之, 平川 由紀子, 佐藤 充孝, 大村 亮, CHUVILIN Evgeny, 鎌田 慈, 竹谷 敏, 長尾 二郎, 内田 努, 海老沼 孝郎, 成田 英夫
    日本エネルギー学会大会講演要旨集 12 90 - 91 一般社団法人日本エネルギー学会 2003年
  • 大村 亮, 内田 努, 竹谷 敏, 池田 育子, 長尾 二郎, 皆川 秀紀, 海老沼 孝郎, 成田 英夫
    年次大会講演論文集 2003 359 - 360 一般社団法人日本機械学会 2003年 [査読無し]
     
    Clathrate hydrate formation in methane/isoamylalcohol (3-methyl-1-butanol)/water system has been demonstrated. The first data of quadruple methane/3-methyl-1-butanol/hydrate/water equilibria have been determined over the temperature range of 274-281 K. The equilibrium pressures at the temperatures below 279 K are lower than those of structure-I hydrate formed in methane/water system without 3-methyl-1-butanol. At the temperatures higher than 279 K, the equilibrium pressures are higher than those of the structure-I methane hydrate. Hydrate crystal samples are prepared under two conditions : at 274 K under 2.55 MPa and at 280.0 K under 6.30 MPa. The crystal samples are then subjected to the Raman-spectroscopy and X-ray-diffraction measurements for the determination of the crystallographic structures of the hydrate crystals. The measurements showed a hydrate phase transition depending on the temperature.
  • S Takeya, Y Kamata, T Uchida, J Nagao, T Ebinuma, H Narita, A Hori, T Hondoh
    CANADIAN JOURNAL OF PHYSICS 81 1-2 479 - 484 2003年01月 [査読無し][通常論文]
     
    X-ray diffraction measurements were conducted to determine the hydrate structures formed from a mixture of CH4 and C2H6 gases at 263 K. With increasing initial fractions of C2H6 in the gas, the crystal structures of the hydrate were structure I, structure I + structure II, structure II, structure I + structure II, and structure I. In situ observations of the growth processes of the mixed gas hydrates under constant gas concentration suggest that the coexistence of structure I and structure II hydrate were caused by occurrences of metastable hydrate structure.
  • T Uchida, S Takeya, LD Wilson, CA Tulk, JA Ripmeester, J Nagao, T Ebinuma, H Narita
    CANADIAN JOURNAL OF PHYSICS 81 1-2 351 - 357 2003年01月 [査読無し][通常論文]
     
    Gas hydrate properties and phase transition kinetics were studied using Raman spectroscopic and X-ray diffraction methods. These techniques have the advantage of measuring physical properties such as crystal structure, gas composition, and cage occupancy of gas molecules without decomposing the sample. In situ observations using these techniques are indicative of formation and decomposition processes in gas hydrates. Raman spectroscopy is used for the analysis of gas concentrations and gas compositions of gas hydrates. The nu(1) symmetrical C-H stretching vibration mode of methane molecules in the hydrate phase shows a doublet, and the relative intensity of the peaks determines the cage-occupancy ratio. However, as the Raman method is not standard for this application, we evaluated the method by analyzing the same methane hydrate sample using NMR and Raman scattering in a laboratory in Canada and also comparing the data with the Raman measurements made on the same sample in a laboratory in Japan. The data were consistent with all three measurements. In addition, in situ measurements of hydrate formation and decomposition were done by X-ray diffraction. The transformation of ice into CO2 hydrates occurred in two steps: at first a CO2 hydrate layer rapidly formed a coating on the ice surface and then the CO2 hydrate slowly grew according to the diffusion rates of CO2 and H2O molecules through the hydrate layer to the reaction sites. The same methods were used to observe the self-preservation effect of methane hydrates.
  • T Uchida, S Takeya, Y Kamata, IY Ikeda, J Nagao, T Ebinuma, H Narita, O Zatsepina, BA Buffett
    JOURNAL OF PHYSICAL CHEMISTRY B 106 48 12426 - 12431 2002年12月 [査読有り][通常論文]
     
    Clathrate hydrates of methane-ethane mixed gases have two crystal structures depending on their composition. To study their compositions and cage occupancies and how their structure is determined, we synthesized hydrate samples from methane-ethane mixtures. Analysis of the samples using X-ray diffraction, Raman spectroscopy, and gas chromatography revealed their structures, compositions, and cage occupancies. Experimentally, hydrate structure II existed in samples formed when the gas equilibrated with hydrates was approximately. 2% C2H6 (molar fraction) whereas both structures I (sI) and II (sII) coexisted for 12 to 22% C2H6. The structures below 2% and above 22% of C2H6 existed only as sI hydrates. Volume ratios of both structures were obtained from the ratio of the peak intensities of the C-C stretching peaks in the Raman spectra. In the transition zone containing both structures, the volume ratio of the sII structure gradually decreased with increasing C2H6 concentration. Cage occupancies of guest molecules in the hydrate cages were determined by the relative intensity ratio of Raman spectra. C2H6 molecules occupied only large cages in both structures, whereas CH4 molecules occupied the remaining cages. The experiments agree with the structure and molecular distributions that were predicted by minimizing the Gibbs free energy of the sample. This model calculation provides insight into the structural transition mechanism.
  • Y Seo, H Lee, T Uchida
    LANGMUIR 18 24 9164 - 9170 2002年11月 [査読有り][通常論文]
     
    Hydrate phase equilibria for the binary CH4 + water and CO2 + water mixtures in silica gel pores of nominal diameters 6.0, 15.0, and 30.0 nm were measured and compared with the calculated results based on van der Waals and Platteeuw model. At a specified temperature, three phase H-L-W-V equilibrium curves of pore hydrates were shifted to the higher pressure region depending on pore sizes when compared with those of bulk hydrates. The activities of water in porous silica gels were expressed with a correction term to account for both capillary effect and activity decrease. By using the values of interfacial tension between hydrate and liquid water phases which were recently presented by Uchida et al.,(5) the calculation values were in better agreement with the experimental ones. The structure and hydration number of CH4 hydrate in silica gel pores (6.0,15.0, and 30.0 nm) were found to be identical with those of bulk CH4 hydrate through NMR spectroscopy.
  • J Nagao, D Nataraj, M Ferhat, T Uchida, S Takeya, T Ebinuma, H Anno, K Matsubara, E Hatta, K Mukasa
    JOURNAL OF APPLIED PHYSICS 92 7 4135 - 4137 2002年10月 [査読有り][通常論文]
     
    Electron tunneling experiments were performed on YbyCo4Sb12-Al oxide-Al junctions for y=0-0.25 at 4.2 K. In the second derivative tunneling spectrum of CoSb3 compound (y=0), three peaks were observed at around 5, 20, and 33 mV, which are closely related to an optical phonon mode with a rigid rectangle, Sb-Sb bond bending and bond stretching, and a large Co atomic motion, respectively. Appearance of the strong peak at 7 mV observed in Yb-filled samples corresponds to a rattled phonon mode of Yb ions. The peak energy due to the Sb-Sb bonds is unchanged, whereas the one due to Co motions shifts to lower with increasing Yb concentration. This fact indicates that the filled Yb ions strongly interact to the host framework Co atoms, which were clearly observed in the change of tunneling conductance. (C) 2002 American Institute of Physics.
  • S Takeya, T Ebinuma, T Uchida, J Nagao, H Narita
    JOURNAL OF CRYSTAL GROWTH 237 Part1 379 - 382 2002年04月 [査読無し][通常論文]
     
    Dissociation rates of methane hydrate and the rate of transformation of methane hydrate into ice Ih were measured using time-resolved, energy-dispersive X-ray diffraction at atmospheric pressure and temperatures between 148 and 253 K. The dissociation of CH4 hydrate had an initially fast regime, which lasted several tens of minutes, followed by slower dissociation. For temperatures from 168 to 198 K, our analysis indicates that the second step was relatively slow because the CH4 had to diffuse through the thickening ice layer. The resulting diffusion coefficients gave an activation energy of 20.1 kJ/mol and equaled 8.7 x 10(-11) m(2) s(-1) at 198 K. (C) 2002 Elsevier Science B.V. All rights reserved.
  • T Uchida, IY Ikeda, S Takeya, T Ebinuma, J Nagao, H Narita
    JOURNAL OF CRYSTAL GROWTH 237 part 1 383 - 387 2002年04月 [査読無し][通常論文]
     
    The lateral growth rate of CO2 hydrate films at the boundary between CO2-saturated water and liquid CO2 at pressures between 15 and 25MPa were measured using an optical microscope. Growth rates ranged from about 6-15 mm/s, depending on the supercooling, and became smaller at higher pressure. We assumed the rate-determining process to be mainly heat transport from the growing interface. This assumption allowed its to interpret the difference of the growth rates between the higher and lower pressure experiments as being due to a difference in hydrate film thickness. The addition of NaCl to the solution, on the other hand, reduced the lateral growth rate. In addition, at a NaCl concentration of 10.1 wt%, the lateral growth rates were remarkably lower than those in lower concentration solutions. These observations suggest that the hydrate growth rate in the NaCl solution is determined by not only the heat transportation, but also the mass transportation of NaCl that might arise from a build up of NaCl at the growing interface. (C) 2002 Elsevier Science B.V. All rights reserved.
  • 海老沼 孝郎, 島田 亙, 大山 裕之, 鎌田 慈, 竹谷 敏, 内田 努, 長尾 二郎, 成田 英夫
    日本エネルギー学会大会講演要旨集 80 82 - 83 一般社団法人日本エネルギー学会 2002年
  • 鎌田 慈, 海老沼 孝郎, 竹谷 敏, 内田 努, 長尾 二郎, 成田 英夫, 門中 章二, 上田 貴夫
    日本エネルギー学会大会講演要旨集 80 96 - 97 一般社団法人日本エネルギー学会 2002年
  • 内田 努, 竹谷 敏, 長尾 二郎, 海老沼 孝郎, 成田 英夫, 森脇 稔, 郷原 一寿, 前 晋爾
    日本エネルギー学会大会講演要旨集 80 80 - 81 一般社団法人日本エネルギー学会 2002年
  • EM Chuvilin, T Ebinuma, Y Kamata, T Uchida, S Takeya, J Nagao, H Narita
    PROCEEDINGS OF THE TWELFTH (2002) INTERNATIONAL OFFSHORE AND POLAR ENGINEERING CONFERENCE, VOL 1 429 - 433 2002年 [査読有り][通常論文]
     
    Experimental results on hydrate and ice formation conditions in the pores of sandy sediments during temperature cycles are presented. To better understand how hydrate accumulates in sandy sediments, we measured the accumulation of CH(4) and CO(2) hydrate and ice in sandy sediments under various conditions. With the pressure above that needed for hydrate formation, cycling the temperature below and above the freezing point of water increased the amount of hydrate in the sediments. The self-preservation effect allowed us to determine the structure and some physical properties of these sediments that contained ice and hydrate.
  • T Uchida, T Ebinuma, S Takeya, J Nagao, H Narita
    JOURNAL OF PHYSICAL CHEMISTRY B 106 4 820 - 826 2002年01月 [査読有り][通常論文]
     
    Equilibrium conditions of CH4, CO2, and C3H8 hydrates confined in small pores of porous glass were determined. The dissociation temperature of each hydrate at a given pressure shifted lower than that for bulk hydrate; the largest shift for CH4 hydrate was -12.3 K +/- 0.2 K for 4-nm-diameter pores and the shift decreased to only -0.5 K for 100-nm pores. CH4 hydrate experiments at temperatures lower than the quadruple point of 270.6 K in 30-nm porous glass showed no shift of the equilibrium line. All temperature shifts were fitted by the Gibbs-Thomson equation; the best fits for CH4, CO2, and C3H8 hydrates predicted hydrate-water interfacial energies of 1.7(3) x 10(-2) J/m(2), 1.4(3) x 10(-2) J/m(2), and 2.5(1) x 10(-2) J/m(2), respectively. Both type-I hydrates of CH4 and CO2 had interfacial energies within 20% of each other but significantly smaller than the type-H hydrate Of C3H8. Ice formation in the same porous glass fit the Gibbs-Thomson relation with an interfacial energy of 2.9(6) x 10(-2) J/m(2), which is in good agreement with established values. The estimated interfacial tensions between gas hydrates and water were found to be only weakly affected by the kinds of gas. This indicated that the pore effect on the phase equilibrium was mainly due to the water activity change. The wide range of experiments on pore size, temperature, and the kind of gas allowed us to evaluate the validity of previous model predictions for pore effects on gas hydrate stability.
  • メタンハイドレートの動的構造因子
    加美山 隆, 伊達 真二, 堀川 卓真, 高峰 潤, 岩佐 浩克, 鬼柳 善明, 成田 英夫, 海老沼 孝郎, 内田 努, S. M. Benningto
    KEK Proceedings 2002-14 58 - 67 2002年 [査読無し][通常論文]
  • NAGAO J, EBINUMA T, UCHIDA T, TAKEYA S, FERHAT M, HATTA E, MUKASA K, ANNO H, MATSUBARA K
    PHYSICA STATUS SOLIDI B-BASIC RESEARCH 228 3 705 - 709 2002年 [査読無し][通常論文]
  • UCHIDA T, TAKEYA S, KAMATA Y, IKEDA I Y, NAGAO J, EBINUMA T, NARITA H, ZATSEPINA O, BUFFETT B A
    J PHYS CHEM B 106 48 12426 - 12431 2002年 [査読無し][通常論文]
  • UCHIDA T, EBINUMA T, TAKEYA S, NAGAO J, NARITA H
    JOURNAL OF PHYSICAL CHEMISTRY B 106 4 820 - 826 2002年 [査読無し][通常論文]
  • YC Song, M Nishio, BX Chen, S Someya, T Uchida, M Akai
    VISUALIZATION AND IMAGING IN TRANSPORT PHENOMENA 972 206 - 212 2002年 [査読無し][通常論文]
     
    The density of CO2 solution was measured by using Mach-Zelmder interferometry in the pressure range from 5.0 to 12.5 MPa, at temperatures from 273.25 to 284.15K, and CO2 mass fraction in solution up to 0.061. It was found that the density difference between the CO2 solution and pure water at the same pressure and temperature is monotonically linear with the CO2 mass fraction. The slope of this linear function, calculated by experimental data fitting, is 0.275.
  • 海老沼 孝郎, 大山 裕之, 伊達 真二, 島田 亙, 竹谷 敏, 長尾 二郎, 内田 努, 成田 英夫
    日本エネルギー学会大会講演要旨集 10 245 - 248 一般社団法人日本エネルギー学会 2001年
  • 大山 裕之, 海老沼 孝郎, 島田 亙, 竹谷 敏, 長尾 二郎, 内田 努, 成田 英夫
    日本エネルギー学会大会講演要旨集 10 249 - 252 一般社団法人日本エネルギー学会 2001年
  • T Uchida, S Takeya, T Ebinuma, H Narita
    GREENHOUSE GAS CONTROL TECHNOLOGIES 523 - 527 2001年 [査読有り][通常論文]
     
    In situ observation of the replacement of methane (CH4) hydrate by CO2 hydrate was carried out via Raman spectroscopy. A temperature-controlled high-pressure vessel was mounted under a microscope to observe the 180-degree scattering light. Measurements of the C-H stretching mode of CH4 in the clathrate at approximately 271 K and 2.9 MPa revealed that the cage occupancy of guest molecules began to significantly decrease 50 hours after the CO2 was introduced. This was caused by that the CH4 molecules in large cages were preferably replaced by C0(2). These spectra disappeared within 50 hours after the beginning of the guest molecule replacing. This suggests that the replacement of guest molecules in clathrate hydrates occurs with the scrap-and-build of the host lattice.
  • TAKEYA S, SHIMADA W, KAMATA Y, EBINUMA T, UCHIDA T, NAGAO J, NARITA H
    JOURNAL OF PHYSICAL CHEMISTRY A 105 42 9756 - 9759 2001年 [査読無し][通常論文]
  • T Uchida, T Ebinuma, H Narita
    JOURNAL OF CRYSTAL GROWTH 217 1-2 189 - 200 2000年07月 [査読有り][通常論文]
     
    We observed CO2 hydrate decomposition and reformation (re-growth) through temperature and pressure changes using a microscope. At pressures above CO2 vapor-liquid equilibrium P-s, decomposition from increasing temperatures left small liquid CO2 drops in the solution phase. Conversely, below P-s, decomposition from increasing temperatures was more rapid due to the release of CO2 gas that mechanically broke the hydrate apart. Similarly, hydrate decomposition by a pressure decrease also released CO2 gas that broke the hydrate apart. Reformation occurred more readily only by cooling, not by a pressure increase. A barrier to CO2 nucleation can explain this memory effect by allowing a greater concentration of CO2 to be left in the aqueous solution after hydrate decomposition. (C) 2000 Elsevier Science B.V. All rights reserved.
  • S Takeya, A Hori, T Hondoh, T Uchida
    JOURNAL OF PHYSICAL CHEMISTRY B 104 17 4164 - 4168 2000年05月 [査読有り][通常論文]
     
    We measured the times to nucleate CO2 hydrates from CO2 dissolved water under pressure and 8.6 K supercooling using different methods to prepare the water. These times ranged from 50 min to more than 7200 min, depending on the preparation method. The nucleation rates were calculated by fitting the observed nucleation probability distributions to a nucleation rate equation. The nucleation rates significantly increased when the water had previously frozen as ice and melted (freezing-memory effect), except when the meltwater was heated to 298 K before nucleation. The nucleation rates also increased with O-2-saturated meltwater, but decreased with degassed water.
  • 内田 努, 伊達 真二, 海老沼 孝郎, 成田 英夫
    日本エネルギー学会大会講演要旨集 9 187 - 190 一般社団法人日本エネルギー学会 2000年
  • S Takeya, T Hondoh, T Uchida
    GAS HYDRATES: CHALLENGES FOR THE FUTURE 912 973 - 982 2000年 [査読有り][通常論文]
     
    In situ observations of CO2 hydrate growth using high-energy X-rays were done at high-pressures and the growth rates of CO2 hydrate from ice particles were measured. Assuming a model of diffusion through CO2 hydrate layers, interdiffusion coefficients of CO2 and H2O molecules were calculated between 233 K and 272.5 K. The diffusion coefficient at 263 K was 7.4 x 10(-16) m(2)/s, and the activation energy of diffusion was 0.40 eV.
  • T Uchida, R Okabe, S Mae, T Ebinuma, H Narita
    GAS HYDRATES: CHALLENGES FOR THE FUTURE 912 593 - 601 2000年 [査読有り][通常論文]
     
    We compared time-resolved Raman spectroscopic measurements of CH4-saturated aqueous solution with CH4 hydrate crystal formed from the same solution. At 287.1 K and 6.6 MPa the C-H stretching mode for CH4 molecules in the solution (nu(sol) = 2911.7 cm(-1)) was intermediate between that in the large cage (nu(L) = 2905.1 cm(-1)) and that in the small cage (nu(S) = 2914.1 cm(-1)), thus indicating an intermediate molecular environment. Comparison of these results with previous work on the CO2-H2O system indicated that water molecules in the type-I small-cage-like structure surrounded CH4 molecules in the solution. Furthermore, the free energy barrier for CH4 hydrate nucleation is likely to be formation of the large cage structure, which is probably larger than that for CO2 hydrate formation.
  • The effect of pressure, temperature and salinity on CO2 dissolution into H2O + NACL
    Someva Satoshi, Nishio Masahiro, Chen Baixin, Okamoto Koji, Uchida Tsutomu
    197 - 203 2000年 [査読無し][通常論文]
     
    <p>Sequestration of liquid CO
    <sub>2</sub> into intermediate depth ocean has been considered as a means to reduce atmospheric concentration of this greenhouse gas and mitigate global warming. A number of CO
    <sub>2</sub> droplets are released into ocean and are diluted. The CO
    <sub>2</sub> solubility into sea water is very important in order to control the amount of released CO
    <sub>2</sub> and environmental impact. Under conditions in the intermediate ocean, that is, high pressure and low temperature, the CO
    <sub>2</sub> clathrate hydrate film was formed on the CO
    <sub>2</sub> droplet surface. The hydrate film has been considered to decrease the dissolution rate and the CO
    <sub>2</sub> concentration at the boundary layer on the droplet surface. In the experiments, LIF technique was used. The CO
    <sub>2</sub> dissolved water emitted intense fluorescence, while the CO
    <sub>2</sub> itself did not illuminate. Therefore, we could know the shrinking rate of CO
    <sub>2</sub> droplet diameter accurately. The CO
    <sub>2</sub> solubility was d
  • CO2液滴の水または海水に対する溶解挙動の観察
    染矢聡, 陳白欣, 西尾匡弘, 岡本孝司, 内田努
    可視化情報 20 77 150 - 157 2000年 [査読無し][通常論文]
     
    <p>Sequestration of liquid CO
    <SUB>2</SUB> into the intermediate depth ocean has been considered as a means to reduce atmospheric concentration of this greenhouse gas and mitigate global warming. A number of CO
    <SUB>2</SUB> droplets are released and diluted into the intermediate ocean. The behavior of CO
    <SUB>2</SUB> dissolution is very important in order to control the concentration of CO
    <SUB>2</SUB> and to keep the environmental impact minimum. Under conditions in the intermediate ocean, that is, high pressure and low temperature, the CO
    <SUB>2</SUB> clathrate hydrate film was formed on the CO
    <SUB>2</SUB> droplet surface. The hydrate film has been considered to decrease the dissolution rate and the CO
    <SUB>2</SUB> concentration near the droplet surface. The authors applied a LIF technique with a new kind of the dye as a pH indicator. The new dye in the CO
    <SUB>2</SUB> dissolved water emitted intense fluorescence dependent on its pH. The visualized images showed the two dimensional distribution of the pH, i.e., CO
    <SUB>2</SUB> concentration, around the CO
  • T Uchida, T Hirano, T Ebinuma, H Narita, K Gohara, S Mae, R Matsumoto
    AICHE JOURNAL 45 12 2641 - 2645 1999年12月 [査読有り][通常論文]
     
    Hydration numbers of methane hydrates with various water/gas ratios of the sample were measured by Raman spectroscopy. Artificial methane hydrates were formed at temperatures ranging from 273.2 to 278.4 K, and pressures from 3.0 to 7.0 MPa, with a stirring rate of approximately 500 rpm. Under such nonequilibrium conditions, the obtained hydrate sample shad a water/gas ratio ranging from 6.4 to 17.4, which was determined by mass measurements. The spectroscopic analysis revealed, however, that the crystallographic hydration number was almost constant at 6.2 +/- 0.2, which corresponds to the hydration number estimated from the thermodynamic model. The same measurements were carried out on natural gas hydrate samples obtained from the deep-sea floor of Blake Ridge. The coincidence of the hydration numbers between natural and artificial samples indicated that the crystallographic hydration number is independent of the formation conditions and the large variation in the water/gas ratio of samples is described by the ratio between pure hydrate and free water.
  • T Uchida, T Ebinuma, J Kawabata, H Narita
    JOURNAL OF CRYSTAL GROWTH 204 3 348 - 356 1999年07月 [査読有り][通常論文]
     
    The formation processes of clathrate-hydrate film are observed at the interface between water and carbon dioxide using microscspy. After a certain induction period, the hydrate him propagates from nucleation points along the interface. A second him propagation is sometimes observed immediately after the primary propagation, which illustrates the molecular distribution near the interface. The dendrite growth following the film coverage of the interface in both phases suggests that the hydrate him grow mainly in the water phase. The propagation rates are determined from video images and are found to depend on the supercooling. This result and the bubble formation on the hydrate film following him propagation indicate that the rate-determining process is mainly heat diffusion from the reaction sites. A him thickness of 0.13 mu m is estimated using the heat diffusion model. (C) 1999 Elsevier Science B.V. All rights reserved.
  • T Uchida, T Ebinuma, T Ishizaki
    JOURNAL OF PHYSICAL CHEMISTRY B 103 18 3659 - 3662 1999年05月 [査読有り][通常論文]
     
    The dissociation conditions of methane hydrates in confined small pores were measured by the gradual temperature increase method. Significant downward shifts of the dissociation temperature were observed in porous glasses, which had small pores ranging from 100 to 500 Angstrom in diameter, compared with that of the bulk hydrate at a given pressure. Systematic measurements revealed that the temperature offset was in inverse proportion to the pore diameter. The Arrhenius plot of the dissociation conditions suggests that the heat of methane-hydrate dissociation tended to be small compared to that of bulk hydrates in pores smaller than 300 A in diameter. Applying the Gibbs-Thomson effect to the quantitative analysis of the phenomenon indicated that the dissociation condition of methane hydrates in small pores shifted because of changes in the water activity. The apparent interfacial free energy between methane hydrates and water in the confined condition was estimated to be approximately 3.9 x 10(-2) J m(-2), which is comparable to that between ice and water in the similar condition.
  • AN Salamatin, T Hondoh, T Uchida, VY Lipenkov
    JOURNAL OF CRYSTAL GROWTH 193 1-2 197 - 218 1998年09月 [査読有り][通常論文]
     
    We present an attempt to model the process of conversion of an air bubble, trapped in ice, to clathrate air-hydrate crystal after its nucleation on the air-ice interface. Both counterparts of the transformation are considered: diffusion of interstitial water and air molecules through the growing hydrate layer that coats the bubble surface, and compressive deformation of the three-phase lair-hydrate-ice) system at a given temperature and load pressure. The mathematical model is constrained by laboratory experiments covering a wide range of thermodynamic conditions. Computational tests show that either diffusion or bubble compression can be the rate-limiting step in the post-nucleation growth of air-hydrate crystal. As a plastic material, air-hydrate appears to be, at least, one order harder than ice. The mass transfer coefficient for the diffusion of air and water molecules in air-hydrate is estimated to be 0.6-1.3 mm(2)/yr at 263 K with the activation energy not higher, than 30-50 kJ/mol. The mass flux of air, although small in comparison with that of water, plays an important role in the conversion. Special attention is paid to the case of air-hydrate growth in air bubbles in polar ice sheets. (C) 1998 Elsevier Science B.V. All rights reserved.
  • 海老沼 孝郎, 内田 努, 吉田 諒一
    日本エネルギー学会大会講演要旨集 7 209 - 212 一般社団法人日本エネルギー学会 1998年
  • T. Uchida, A. Takagi, S. Mae, J. Kawabata
    Energy Conversion and Management 38 1 S307 - S312 1997年 
    In situ Raman spectroscopic measurements were performed in a CO2 + H2O system. When aqueous CO2 coexisted with the hydrate, CO2 spectra were different from those obtained when the hydrate was absent. Spectral analysis indicated that the water structure surrounding a CO2 molecule in solutions with hydrates resembled conditions in the hydrate. © 1997 Elsevier Science Ltd.
  • 長田 英治, 内田 努, 平野 貴史, 郷原 一寿, 前 晋爾
    日本エネルギー学会大会講演要旨集 6 227 - 230 一般社団法人日本エネルギー学会 1997年
  • 内田 努, 海老沼 孝郎, 平野 貴史, 前 晋爾, 竹谷 敏, 本堂 武夫, 松本 良
    日本エネルギー学会大会講演要旨集 6 223 - 226 一般社団法人日本エネルギー学会 1997年
  • 海老沼 孝郎, 内田 努, 成田 英夫, 吉田 諒一
    日本エネルギー学会大会講演要旨集 6 231 - 234 一般社団法人日本エネルギー学会 1997年
  • 内田 努, 高木 哲史, 平野 貴史, 成田 英夫, 河端 淳一, 前 晋爾
    日本エネルギー学会大会講演要旨集 5 122 - 125 一般社団法人日本エネルギー学会 1996年
  • H Itoh, S Horikawa, K Kawamura, T Uchida, T Hondoh, S Mae
    NGH '96 - 2ND INTERNATIONAL CONFERENCE ON NATURAL GAS HYDRATES, PROCEEDINGS 341 - 346 1996年 [査読有り][通常論文]
  • T Uchida, A Takagi, T Hirano, H Narita, J Kawabata, T Hondoh, S Mae
    NGH '96 - 2ND INTERNATIONAL CONFERENCE ON NATURAL GAS HYDRATES, PROCEEDINGS 335 - 339 1996年 [査読有り][通常論文]
  • H Narita, T Uchida
    NGH '96 - 2ND INTERNATIONAL CONFERENCE ON NATURAL GAS HYDRATES, PROCEEDINGS 191 - 197 1996年 [査読有り][通常論文]
  • T UCHIDA, W SHIMADA, T HONDOH, S MAE, NI BARKOV
    APPLIED OPTICS 34 25 5746 - 5749 1995年09月 [査読有り][通常論文]
     
    The refractive index of air-hydrate crystals found in a deep Antarctic ice sheet was measured for the first time, as far as we know, using a Mach-Zehnder interferometer. A small difference between the refractive indices of the air-hydrate crystals and the matrix ice crystal was measured by the fringe-shift method. It was found that the refractive indices of all air-hydrate crystals were larger than those of ice, and the average difference was 5.3 x 10(-3), even considering the refractive-index anisotropy of ice crystals. Because the refractive indices depend on the occupancy ratio of cagelike cavities by air molecules, we compared the experimental results with the calculated values using the Onsager cavity model. We determined that the present method is useful for estimation of the cavity occupancy ratio of air-hydrate crystals and also of the amount of air molecules in polar ice cores.
  • T UCHIDA, A TAKAGI, J KAWABATA, S MAE, T HONDOH
    ENERGY CONVERSION AND MANAGEMENT 36 6-9 547 - 550 1995年06月 [査読有り][通常論文]
     
    CO2 hydrate crystals with polyhedral facet were observed to grow from CO2 solution. For both CO2 hydrates and CO2 solution, raman spectroscopic analyses were carried out. Raman spectra of CO2 and H2O molecules in CO2 hydrate were different from those in CO2 solution. We presented an attempt to estimate the density of CO2 hydrate by the raman intensity ratio, and found that the densities of CO2 hydrates were considerably smaller than those used in some modeling studies.
  • T UCHIDA, T HONDOH, S MAE, VY LIPENKOV, P DUVAL
    JOURNAL OF GLACIOLOGY 40 134 79 - 86 1994年 [査読有り][通常論文]
     
    Microscopic observation of air-hydrate crystals was carried out using 34 deep ice-core samples retrieved at Vostok Station, Antarctica. Samples were obtained from depths between 1050 and 2542 m, which correspond to Wisconsin/Sangamon/Illinoian ice. It was found that the volume and number of air-hydrate varied with the climatic changes. The volume concentration of air-hydrate in the interglacial ice was about 30% larger than that in the glacial ice. In the interglacial ice, the number concentration of air-hydrate was about a half and the mean volume of air-hydrate was nearly three times larger than that in the glacial-age ice. The air-hydrate crystals were found to grow in the ice sheet, about 6.7 x 10(-12) cm3 year-1, in compensation for the disappearance of smaller ones. The volume concentration of air-hydrate was related to the total gas content by a geometrical equation with a proportional parameter alpha. The mean value of alpha below 1250 m, where no air bubbles were found, was about 0.79. This coincided with an experimentally determined value of the crystalline site occupancy of the air-hydrate in a 1500 m core obtained at Dye 3, Greenland (Hondoh and others, 1990). In the depth profile of calculated alpha for many samples, alpha in the interglacial ice was about 30% smaller than that in the glacial-age ice.

MISC

  • 内田 努 えねるみくす = Enermix : 日本エネルギー学会機関誌 103 (2) 179 -184 2024年03月
  • トレハロースを用いたアクアポリン4発現CHO細胞の凍結速度依存性
    松尾 菫, 山崎 憲慈, 安井 正人, 阿部 陽一郎, 内田 努 低温生物工学会セミナー及び年会講演要旨集 67回 31 -31 2022年06月
  • 内田 努 日本エネルギー学会機関誌えねるみくす 100 (2) 176 -177 2021年03月20日
  • 内田努, 法花翼, 黄川田隆洋, 黄川田隆洋, 津田栄, 山崎憲慈, 郷原一壽 雪氷研究大会講演要旨集(Web) 2021 2021年
  • 大藪 幾美, 川村 賢二, 内田 努, 藤田 秀二, 北村 享太郎, 平林 幹啓, 青木 周司, 森本 真司, 中澤 高清, Severinghaus Jeffrey P., Morgan Jacob 雪氷研究大会講演要旨集 2021 30 -30 2021年
  • 内田 努, 繁山 航, 大藪 幾美, 東 久美子, 中澤 文男, 本間 智之, 川村 賢二, Dahl-Jensen Dorthe 雪氷研究大会講演要旨集 2021 185 -185 2021年
  • 内田 努, 法花 翼, 黄川田 隆洋, 津田 栄, 山崎 憲慈, 郷原 一壽 雪氷研究大会講演要旨集 2021 72 -72 2021年
  • 内田努, 法花翼, 黄川田隆洋, 黄川田隆洋, 津田栄, 山崎憲慈, 郷原一壽 低温生物工学会セミナー及び年会講演要旨集 66th 2021年
  • 黎明期のガスハイドレート研究者たち
    内田努 日本のガスハイドレート研究の歩み～黎明期から最先端まで～ 75 -77 2020年09月 [査読無し][通常論文]
  • ガスハイドレート研究の時間軸とGH研究会の歩み
    内田努, 佐藤幹夫 日本のガスハイドレート研究の歩み～黎明期から最先端まで～ 7 -22 2020年09月 [査読無し][通常論文]
  • 水で育まれる生命
    内田 努 理科教室 62 (7) 59 -64 2019年07月 [査読無し][招待有り]
  • トレハロースによるCHO-TRET1細胞の凍結保存実験 細胞内へのトレハロース輸送量の飽和量
    内田 努, 黄川田 隆洋, 古川 真帆, 山崎 憲慈, 郷原 一寿 低温生物工学会セミナー及び年会講演要旨集 64回 20 -20 2019年06月
  • 内田 努, 三好 洋志, 山崎 憲慈, 郷原 一寿 雪氷研究大会講演要旨集 2019 167 2019年
  • 内田 努 えねるみくす 98 (1) 52 -55 2019年01月 [査読無し][通常論文]
     
    生物とガスハイドレートとの関係は，半世紀以上の歴史を持つ古くて新しい課題である。ここでは麻酔と鮮度保持という研究分野から，これまでの研究の概略を紹介し，ガスハイドレートの実験的研究との接点を考える。
  • 内田 努 えねるみくす 98 (1) 29 -33 2019年01月 [査読無し][招待有り]
     
    本学会の天然ガス部会資源分科会の下にメタンハイドレート研究会（現：GH研究会）が創設されてから，昨年で50回の節目を迎え，まもなく20周年を迎えようとしている。今回，えねるみくす誌上で２回にわたって本研究会の活動を紹介させていただく機会を得た。本稿では，GH研究会の歩みを簡単に紹介する。
  • 長島 大典, 安田 啓太, 内田 努, 大村 亮 冷凍 93 (1091) 600 -605 2018年09月 [査読無し][招待有り]
  • 内田 努 冷凍 93 (1091) 581 -585 2018年09月 [査読無し][招待有り]
  • 内田努, 古川真帆, 黄川田隆洋, 黄川田隆洋, 山崎憲慈, 郷原一寿 雪氷研究大会講演要旨集(Web) 2018 2018年
  • 内田努, 古川真帆, 黄川田隆洋, 黄川田隆洋, 山崎憲慈, 郷原一寿 高分子学会予稿集(CD-ROM) 67 (2) 2018年
  • 内田 努, 古川 真帆, 黄川田 隆洋, 山崎 憲慈, 郷原 一寿 雪氷研究大会講演要旨集 2018 151 2018年
  • CHO細胞の凍結保存に最適な細胞内トレハロース濃度の推定
    内田 努, 古川 真帆, 黄川田 隆洋, 山崎 憲慈, 郷原 一寿 低温生物工学会セミナー及び年会講演要旨集 62回 G17 -G17 2017年05月
  • 内田 努 雪氷 79 (5) 415 -424 2017年 [査読無し][招待有り]
  • 佐藤 幹夫, 長久保 定雄, 内田 努, 谷 篤史 Journal of the Japan Institute of Energy = 日本エネルギー学会誌 95 (7) 572 -585 2016年07月
  • 木田 真人, 内田 努 Journal of the Japan Institute of Energy = 日本エネルギー学会誌 95 (5) 398 -406 2016年05月
  • 内田努, 古川真帆, 黄川田隆洋, 黄川田隆洋, 山崎憲慈, 郷原一寿 雪氷研究大会講演要旨集(Web) 2016 2016年
  • 内田 努, 山崎 憲慈, 郷原 一寿 雪氷研究大会講演要旨集 2016 207 2016年
  • 内田 努, 古川 真帆, 黄川田 隆洋, 山崎 憲慈, 郷原 一寿 雪氷研究大会講演要旨集 2016 100 2016年
  • 川村 賢二, 本山 秀明, 東 久美子, 藤田 秀二, 古川 晶雄, 中澤 文男, 青木 周司, 東 信彦, 阿部 彩子, 飯塚 芳徳, 植村 立, 内田 努, 大野 浩, 亀田 貴雄, 鈴木 利孝, 高田 守昌, 平林 幹啓, 藤田 耕史, 福井 幸太郎, 堀 彰, 堀内 一穂, 的場 澄人, 宮本 淳 雪氷研究大会講演要旨集 2016 194 2016年
  • トレハローストランスポーターを発現したCHO-K1細胞の凍結保存 トレハロース濃度依存性
    古川 真帆, 内田 努, 黄川田 隆洋, 山崎 憲慈, 郷原 一寿 低温生物工学会セミナー及び年会講演要旨集 60回 31 -31 2015年05月
  • 堀 彰, 竹谷 敏, 内田 努, 大村 亮, 木田 真人 日本物理学会講演概要集 69 (2) 218 -218 2014年08月22日 [査読無し][通常論文]
  • 内田 努, 岸 大輔, 志賀 俊樹, 永山 昌史, 郷原 一寿 雪氷研究大会講演要旨集 2014 218 2014年
  • 内田 努 雪氷 : 日本雪氷協會雜誌 75 (1) 28 -29 2013年01月30日
  • 内田 努, 竹谷 敏 日本結晶成長学会誌 = Journal of the Japanese Association for Crystal Growth 40 (4) 238 -243 2013年 [査読無し][通常論文]
     
    Disaccharides are expected to be the natural cryoprotecting materials for living bodies and cells. However, since they are too large to permeate the biomembrane, the cryopreservation mechanism has not been revealed. The microscopic-scale observations on the freezing process of dissacharide solutions provided new insight of this mechanism. Two kinds of experiments, the transmission electron microscopic observations of freeze-fractured replica films and the powder x-ray diffraction measurements, on the quenched trehalose solutions revealed that the crystal growth of ice Ih crystallites was inhibited to grow by the non-crystalline trehalose phase. In addition, it was found that the quasi-stable phase of cubic ice (Ic) were formed in the large concentration samples. Since the stability of ice Ic was extended as high as approximately 243 K, it was considered that the meso-pore space stabilizing ice Ic was maintained until the trehalose molecules broke off their hydrogen-bonded network at the vitrification temperature. Based on the formation and anomalous stability of ice Ic, the compartment-like structure formed by the disaccaride molecules in the original solution would inhibit the growth of ice Ih, which results in the cryoprotective effect.
  • 永山 昌史, 清水 恭子, 平 敏夫, 内田 努, 郷原 一寿 肥満研究 18 (Suppl.) 178 -178 2012年09月
  • 内田 努 セラミックス 47 (5) 367 -373 2012年05月01日
  • M. Nagayama, K. Shimizu, T. Taira, T. Uchida, K. Gohara MOLECULAR BIOLOGY OF THE CELL 23 183 2012年 [査読無し][通常論文]
  • 王蕾, 大下誠一, 内田努, 竹谷敏, 川越義則, 牧野義雄, 米山明男 農業環境工学関連学会合同大会講演要旨集(CD-ROM) 2012 2012年
  • 永山 昌史, 清水 恭子, 平 敏夫, 内田 努, 郷原 一寿 肥満研究 17 (Suppl.) 201 -201 2011年09月
  • 渡邉 弘務, 内田 努, 郷原 一寿, 永山 昌史 肥満研究 17 (Suppl.) 202 -202 2011年09月
  • 脂肪分解刺激による脂肪滴の収縮とそれに続く新規生成・成長(Shrinking and subsequent development of lipid droplets in 3T3-L1 adipocytes during lipolysis)
    渡邉 弘務, 内田 努, 郷原 一寿, 永山 昌史 日本細胞生物学会大会講演要旨集 63回 142 -142 2011年05月
  • 内田 努 月刊海洋 = Kaiyo monthly / 月刊海洋編集部 編 43 (2) 55 -59 2011年02月
  • 内田 努, 宮本 淳, 本堂 武夫 雪氷研究大会講演要旨集 2011 165 -165 2011年 [査読有り][通常論文]
  • Microscopic observations of sintering processes on gas hydrate particles
    T. Uchida, T. Shiga, M. Nagayama, K. Gohara, T. Sakurai Proc. of 7th Int. Conf. on Gas Hydrates P-347 2011年 [査読無し][通常論文]
  • 内田 努, 佐崎 元, 古川 義純, 田崎 友衣子, 谷 篤史, 灘 浩樹, 坂下 真実, 櫻井 俊光, 保井 みなみ, 深澤 裕, 竹谷 敏 雪氷 : 日本雪氷協會雜誌 72 (6) 391 -396 2010年11月15日 [査読無し][通常論文]
  • 永山 昌史, 清水 恭子, 平 敏夫, 内田 努, 郷原 一寿 肥満研究 16 (Suppl.) 150 -150 2010年09月
  • 内田 努, 竹谷 敏 日本物理学会講演概要集 65 (2) 329 -329 2010年08月18日 [査読無し][通常論文]
  • 内田 努, 竹谷 敏 日本物理学会講演概要集 65 (2) 866 -866 2010年08月18日 [査読無し][通常論文]
  • 内田 努, 大村 亮, 堀 彰 アンサンブル 12 (3) 3 -7 2010年07月 [査読無し][通常論文]
  • カテコールアミンで刺激された脂肪細胞における脂肪滴の収縮と生成(Simultaneous shrinking and development of lipid droplets in adipocytes stimulated with catecholamine)
    永山 昌史, 清水 恭子, 平 敏夫, 内田 努, 郷原 一寿 日本細胞生物学会大会講演要旨集 62回 208 -208 2010年05月
  • 内田 努, 志賀 俊樹, 永山 昌史, 郷原 一寿 雪氷研究大会講演要旨集 2010 112 -112 2010年 [査読有り][通常論文]
  • T. Sakurai, A. Miyamoto, Y. Iizuka, T. Hondoh, T. Uchida, S. Fujita Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research 2010 109 -109 2010年01月01日 [査読無し][通常論文]
  • 永山 昌史, 清水 恭子, 平 敏夫, 内田 努, 郷原 一寿 肥満研究 15 (Suppl.) 245 -245 2009年09月
  • 内田 努 雪氷 : journal of the Japanese Society of Snow and Ice / 日本雪氷学会 編 71 (5) 317 -393 2009年09月 
    記事種別: 特集
  • 脂肪細胞におけるノルエピネフリン誘導性の脂肪滴収縮および生成(Norepinephrine-induced shrinking and development of lipid droplets in adipocytes)
    永山 昌史, 清水 恭子, 平 敏夫, 内田 努, 郷原 一寿 日本細胞生物学会大会講演要旨集 61回 174 -174 2009年05月
  • 川村 太郎, 樋口 知, 山本 佳孝, 川辺 能成, 原 淳子, 内田 努, 大賀 光太郎 日本エネルギー学会大会講演要旨集 18 70 -71 2009年 
    Clathrate formation from coal bed methane and its drained water has been investigated experimentally, aiming an efficient transport system of coal bed methane. Obtained phase equilibrium data of drained water suggested slight higher pressure at same temperature than that of pure water. Condensation of ingredient in drained water was observed after clathrate formation.
  • 内田 努, 木田 真人, 長尾 二郎 雪氷研究大会講演要旨集 2009 218 -218 2009年 [査読有り][通常論文]
  • 「一般教育演習「水の科学 エネルギー・環境～生命」からの報告
    内田 努 水科学研究会第100回記念随筆集 33 -39 2009年 [査読無し][通常論文]
  • 氷物性 ―氷コアから過去の情報を読み解く鍵―
    内田 努 雪氷研究の系譜－北海道の雪氷から世界の雪氷圏まで－ 61 -65 2009年 [査読無し][通常論文]
  • 永山 昌史, 清水 恭子, 平 敏夫, 内田 努, 郷原 一寿 可視化情報学会誌. Suppl. = Journal of the Visualization Society of Japan 28 (2) 157 -158 2008年09月15日 [査読無し]
  • 永山 昌史, 清水 恭子, 平 敏夫, 内田 努, 郷原 一寿 肥満研究 14 (Suppl.) 233 -233 2008年09月
  • 脂肪細胞の分化および脂肪分解時における脂肪滴の非同期的な挙動(Asynchronous behavior of lipid droplets in adipocytes during differentiation and lipolysis)
    永山 昌史, 内田 努, 平 敏夫, 清水 恭子, 郷原 一寿 日本細胞生物学会大会講演要旨集 60回 144 -144 2008年06月
  • 内田 努, 宮村 謙一郎, 永山 昌史, 郷原 一寿 雪氷研究大会講演要旨集 2008 31 -31 2008年 [査読有り][通常論文]
  • T. Sakurai, Y. Iizuka, S. Horikawa, T. Hondoh, T. Uchida Summaries of JSSI and JSSE Joint Conference on Snow and Ice Research 2008 79 -79 2008年01月01日 [査読無し][通常論文]
  • 内田 努 高圧力の科学と技術 18 (2) 173 -179 2008年 [査読無し][招待有り]
     
    Gas hydrates are crystalline inclusion compounds in which guest molecules (e.g. methane and carbon dioxide) stabilize the cages formed by hydrogen bonded H2O molecules at low temperature and suitable pressure. Since these materials are interested in various research fields, the understanding of their unique properties sometimes requires the collaborations beyond the research fields. This review shows some interesting phenomena of gas hydrates, which have been recently studied actively.
  • 内田 努 情報知識学会誌 18 (3) 280 -285 2008年 [査読無し][招待有り]
     
    ２００１年より，CODATA のTask group として，ガスハイドレートに関する国際データベースの構築プロジェクトが行なわれている．このプロジェクトは，日本でも現在非在来型天然ガス資源のひとつとして注目を集めているガスハイドレートに関して，世界中に散在するデータベースをひとつのポータル上でリンクさせ，仮想的な国際データベースを構築するものである．本稿では，これまでのTask group の活動を紹介し，国際データベースのスキームをまとめた．同時に，国内のガスハイドレート研究者を中心に行ったアンケート調査の結果をまとめ，データベース構築に対する意識について報告する．この報告をもとに，現在の日本国内におけるガスハイドレート研究の現状を紹介するとともに，データベース構築に対する問題点を考察した．
  • Inelastic Neutron Scattering Study of Host and Guest Molecular Motions in Methane Hydrates
    Kamiyama, T, Seki, N, Iwasa, H, Uchida, T, Kiyanagi, Y, Ebinuma, T, Narita, H, Igawa, N, Ishii, Y, Bennington, S Proceedings of 6th International Conference on Gas Hydrates P-103 2008年 [査読無し][通常論文]
  • Raman Spectroscopic Measurements on Fluoromethane Clathrate Hydrates
    Uchida, T, Ohmura, R, Hori, A Proceedings of 6th International Conference on Gas Hydrates P-314 2008年 [査読無し][通常論文]
  • Stability of Methane, Fluoromethane and Chloromethane Clathrate Hydrates Investigated by the First Principle Calculations
    Hori, A, Takeya, S, Ohmura, R, Uchida, T Proceedings of 6th International Conference on Gas Hydrates P-065 2008年 [査読無し][通常論文]
  • 永山 昌史, 内田 努, 平 敏夫, 清水 恭子, 郷原 一寿 生物物理 47 (Suppl.1) S164 -S164 2007年11月
  • 谷脇 伸也, 腰原 由公, 内田 努, 永山 昌史, 平 敏夫, 清水 恭子, 郷原 一寿 生物物理 47 (Suppl.1) S165 -S165 2007年11月
  • 永山 昌史, 内田 努, 平 敏夫, 清水 恭子, 郷原 一寿 肥満研究 13 (Suppl.) 289 -289 2007年09月
  • 脂肪細胞分化時の一次間質-血管細胞の非同期動作(Asynchronous Behavior of Primary Stromal-vascular Cells during Adipocyte Differentiation)
    永山 昌史, 内田 努, 平 敏夫, 清水 恭子, 酒井 雅人, 郷原 一寿 日本発生生物学会・日本細胞生物学会合同大会要旨集 40回・59回 186 -186 2007年05月
  • 本堂 武夫, 内田 努, 竹井 巌, 奥地 拓生, 佐々木 重雄, 崛 彰, 前野 紀一, 荒川 政彦 雪氷 69 (1) 95 -100 2007年01月15日 [査読無し][通常論文]
  • 内田 努 分離技術 37 (2) 93 -99 2007年 [査読無し][招待有り]
     
    特集 ハイドレート資源開発と複雑系の物性
  • 永山昌史, 内田努, 平敏夫, 清水恭子, 郷原一寿 肥満研究 13 (1) 84 -86 2007年 [査読無し][招待有り]
  • 永山 昌史, 内田 努, 平 敏夫, 清水 恭子, 酒井 雅人, 郷原 一寿 肥満研究 12 (Suppl.) 220 -220 2006年09月
  • 加美山 隆, 鬼柳 善明, 岩佐 浩克, 内田 努, 海老沼 孝郎, 成田 英夫, Bennington S.M 低温科学 64 215 -222 2006年03月22日 [査読無し][通常論文]
     
    中性子が物質中の原子や分子の熱運動程度のエネルギーを持つと,その波長は原子サイズのオーダーになる.これにより,X線の回折と同様な条件の下,凝集体の回折現象の測定が可能となるうえ,原子・分子の熱運動と中性子の間のエネルギーのやり取りを観測しやすい.つまり,中性子散乱実験では,凝集体の空間的な構造と運動に関する情報,すなわち動的構造を一挙に得ることが可能となる.ここでは,この中性子散乱測定の特長を活かしてメタンハイドレートの測定を行い,得られた3次元的な構造を持つスペクトルからメタン分子の微視的な運動を詳細に解析した例を示す.
  • 永山 昌史, 内田 努, 平 敏夫, 清水 恭子, 星 卓也, 酒井 雅人, 郷原 一寿 肥満研究 11 (Suppl.) 169 -169 2005年09月
  • 内田 努, 永山 昌史, 郷原 一寿, 加我 晴生 日本雪氷学会全国大会講演予稿集 2005 161 -161 2005年
  • Dynamical structure of methane hydrate measured by neutron inelasitic scattering
    Kiyanagi, Y, Kamiyama, T, Ohnuma, S, Hiraga, F, Uchida, T, Ebinuma, T, Narita, H, Bennington, S Proc. of 5th Int. Conf. on Gas Hydrates 502 -506 2005年 [査読無し][通常論文]
  • Mechanism of self-preservation during dissociation of methane clathrate hydrate
    Shimada, W, Takeya, S. Kamata, Y, Uchida, T, Nagao, J, Ebinuma, T, Narita, H Proc. of 5th Int. Conf. on Gas Hydrates 208 -212 2005年 [査読無し][通常論文]
  • The stabilities of structure-H gas hydrates including various guests evaluated from the cohesive energy calculations by the semiempirical molecular orbital method
    Hori, A, Ohmura, R, Takeya, S, Uchida, T Proc. of 5th Int. Conf. on Gas Hydrates 664 -667 2005年 [査読無し][通常論文]
     
    Hori, A., Ohmura, R., Takeya, S. and Uchida, T.
    “The stabilities of structure-H gas hydrates including various guests evaluated from the cohesive energy calculations by the semiempirical molecular orbital method”
    Proc. of 5th Int. Conf. on Gas Hydrates，664-667, 2005
  • 内田努, 伊藤英之助 低温科学 64 173 -181 2005年 [査読無し][通常論文]
     
    3章 クラスレートハイドレート研究のフロンティア
  • Structure analysis of clathrate hydrate crystals formed from methane + water and large-molecule substances
    Takeya, S, Ohmura, R, Uchida, T, Hori, A Proc. of 5th Int. Conf. on Gas Hydrates 643 -647 2005年 [査読無し][通常論文]
  • 中性子散乱で見るメタンハイドレートの動的構造
    加美山隆, 鬼柳善明, 岩佐浩克, 内田努, 海老沼孝郎, 成田英夫, Bennington, S. M 低温科学 64 215 -222 2005年 [査読無し][通常論文]
  • Phase equilibrium measurements and crystallographic analyses on structure-H type gas hydrate formed from CH4-CO2-neohexane-water system
    Uchida, T, Ohmura, R, Ikeda, I. Y, Kamata, Y, Nagao, J, Takeya, S Proc. of 5th Int. Conf. on Gas Hydrates 580 -585 2005年 [査読無し][通常論文]
     
    Uchida, T., Ohmura, R., Ikeda, I. Y., Kamata, Y., Nagao, J. and Takeya, S.
    “Phase equilibrium measurements and crystallographic analyses on structure-H type gas hydrate formed from CH4-CO2-neohexane-water system”
    Proc. of 5th Int. Conf. on Gas Hydrates，580-586, 2005
  • Uchida, Tsutomu, Takeya, Satoshi, Chuvilin, Evgene M., Ohmura, Ryo, Nagao, Jiro, Yakushev, Vladimir S., Istomin, Vladimir A., Minagawa, Hideki, Ebinuma, Takao, Narita, Hideo Journal of Geophysical Research - Solid Earth (Chemistry and Physics of Minerals and Rocks/Volcanology) 109 (B5) B05206 2004年05月11日 
    An edited version of this paper was published by AGU. Copyright 2004 American Geophysical Union.
  • 兵動 正幸, チュビリン M. エフゲニー, 海老沼 孝郎, 内田 努 土と基礎 = Soil mechanics and foundation engineering 52 (2) 53 -58 2004年02月01日 [査読無し][通常論文]
  • 内田 努, 永山 昌史, 柴山 環樹, 郷原 一寿 日本雪氷学会全国大会講演予稿集 2004 82 -82 2004年
  • 兵動正幸, E.M. Chuvilin, 海老沼孝郎, 内田努 土と基礎 52 (2) 53 -58 2004年 [査読無し][招待有り]
  • 竹谷敏, 長尾二郎, 島田亙, 神繁樹, 内田努, 皆川秀紀, 大村亮, 海老沼孝郎, 成田英夫 資源・素材 2003 (A/B) 245-246 -246 2003年09月22日 [査読無し][通常論文]
  • 島田 亙, 海老沼 孝郎, 近藤 英昌, 大山 裕之, 鎌田 慈, 竹谷 敏, 内田 努, 長尾 二郎, 成田 英夫 日本結晶成長学会誌 30 (3) 117 -117 2003年07月05日 [査読無し][通常論文]
     
    Tetra-n-Butyl Ammonium Bromide (TBAB: (C_4H_9)_4N・Br) forms a semi-clathrale hydrate crystal with water molecules under atmospheric pressure. We found that TBAB-hydrate could encage methane molecules in mixtures of methane and propane or methane and ethane. Our preliminary result of single-crystal analysis using X-ray shows that TBAB-hydrate has empty cages, all of which are small. dodecahedral cages. Therefore, TBAB-hydrale crystals can be used to separate small gas molecules that fit in these dodecahedral cages.
  • 内田 努 雪氷 : 日本雪氷協會雜誌 65 (1) 81 -82 2003年01月15日 [査読無し][通常論文]
  • T Uchida, R Ohmura, S Takeya, J Nagao, H Minagawa, T Ebinuma, H Narita GREENHOUSE GAS CONTROL TECHNOLOGIES, VOLS I AND II, PROCEEDINGS II 1679 -1682 2003年 [査読無し][通常論文]
     
    The interfacial tension between liquid CO2 and water or NaCl solution was measured by a simple sessile-drop method at pressures up to 25 MPa and at temperatures of 278 and 288 K. The interfacial tension between liquid CO2 and pure water was approximately 38 mN m(-1) at 288 K and 5 MPa with a small pressure dependence, whereas the values between liquid CO2 and 3 wt% NaCl solution were more than 10 % larger than those between liquid CO2 and pure water. At 278 K, CO2 hydrate is stable and the interfacial tension has larger pressure dependence. This might be related to the supersaturation prior to hydrate formation.
  • 島田 亙, 海老沼 孝郎, 大山 裕之, 竹谷 敏, 内田 努, 長尾 二郎, 成田 英夫 日本結晶成長学会誌 29 (2) 48 -48 2002年07月01日 [査読無し][通常論文]
     
    Tetra-n-Butyl Ammonium Bromide (TBAB: (C_4H_9)_4N・Br) forms a semiclathrate-hydrate crystal with water molecules under atmospheric pressure. We carried out in situ observation of this crystal to investigate the growth mechanism of hydrate crystals. The morphology of growing crystal depends on the supercooling. The growth velocity of bottom plane was a function of supercooling. On the other hand, the side plane did not grow under the supercooling 1.4 K. We concluded that the growth of TBAB semiclathrate-hydrate crystals is extremely prohibited by intertacial kinetics.
  • 竹谷 敏, 内田 努, 長尾 二郎, 大村 亮, 海老沼 孝郎, 成田 英夫, 堀 彰, 本堂 武夫 日本結晶成長学会誌 29 (2) 49 -49 2002年07月01日 [査読無し][通常論文]
     
    In-situ observations of CO_2 hydrate and N_2 hydrate growth using a high-energy X-rays were done at high-pressures, and growth rates of each hydrate from ice particles were measured. Assuming a model of diffusion in the hydrate layers, mass-diffusion coefficients of guest molecules and H_2O molecules were calculated.
  • 内田 努 エネルギー・資源 23 (2) 114 -117 2002年03月05日 [査読無し][通常論文]
  • 内田 努, 竹谷 敏 日本エネルギー学会誌 = Journal of the Japan Institute of Energy 80 (9) 871 -880 2001年09月20日 [査読無し][通常論文]
  • 宋永臣, 西尾匡弘, 陳白欣, 染矢聡, 内田努 化学工学会秋季大会研究発表講演要旨集 34th 685 2001年08月31日 [査読無し][通常論文]
  • 内田 努 日本結晶成長学会誌 28 (2) 70 -76 2001年06月26日 [査読無し][通常論文]
     
    Gas hydrate crystal is one of the clathrate compounds in which a large number of gas molecules are trapped inside well-defined cages formed by water molecules' Huge amount of gas hydrates naturally exists in the sediments of deep seas and of the permafrost, which are expected to be one of the future resources or the sources of the carbon cycle Recently gas hydrates are also expected to be applied to the engineering utilization or to the functional material agree to the environment. To estimate the effect of the gas hydrates on the global environments and on the human activities, the knowledge of the crystallographic characteristics and of the growth mechanisms are important. This paper overviews the recent activities of the hydrate study the order of the growth mechanisms.
  • Satoshi Someya, Masahiro Nishio, Baixin Chen, Koji Okamoto, Tsutomu Uchida American Society of Mechanical Engineers, Heat Transfer Division, (Publication) HTD 366 237 -243 2000年12月01日 [査読無し][通常論文]
     
    Sequestration of liquid CO2 into the intermediate depth ocean has been considered as a means to reduce atmospheric concentration of this greenhouse gas and mitigate global warming. A number of CO2 droplets are released and diluted into the intermediate ocean. The behavior of CO2 dissolution is very important in order to control the concentration of CO2 and to keep the environmental impact minimum. Under conditions in the intermediate ocean, that is, high pressure and low temperature, the CO2 clathrate hydrate film was formed on the CO2 droplet surface. The hydrate film has been considered to decrease the dissolution rate and the CO2 concentration near the droplet surface. The authors applied a LIF technique with a new kind of the dye as a pH indicator. The new dye in the CO2 dissolved water emitted intense fluorescence dependent on its pH. The visualized images showed the two dimensional distribution of the pH, i.e., CO2 concentration, around the CO2 droplet with or without the hydrate film.
  • 内田 努, 竹谷 敏, 海老沼 孝郎, 成田 英夫 日本結晶成長学会誌 27 (1) 57 -57 2000年07月01日 [査読無し][通常論文]
     
    Dynamic Light Scattering spectrophotometer was applied to observe the formation process of gas hydrates. The viscosity of the solution with the uniform nicroparticles was measured under both atmospheric and CO_2 pressurized conditions. Results verified the validity of this method, and indicated the change of viscosity of CO_2 solution under the hydrate stability conditions.
  • 竹谷 敏, 堀 彰, 内田 努, 海老沼 孝郎, 成田 英夫, 本堂 武夫 日本結晶成長学会誌 27 (1) 71 -71 2000年07月01日 [査読無し][通常論文]
     
    We measured the times to nucleate CO_2 hydrates from CO_2 dissolved water different methods to prepare the water. The times ranged from 50 min to more than 7200 min, depending on the preparation method. The nucleation rates were calculated by fitting a nucleation rate equation with the observed nucleation probabilities. The nucleation rates significant increased when the water had previously frozen as ice and melted. The nucleation rates also increased with O_2-saturated water, but decreased with degassed water.
  • 染矢 聡, 陳 白欣, 西尾 匡弘, 岡本 孝司, 内田 努 可視化情報学会誌 = Journal of the Visualization Society of Japan 20 (77) 150 -157 2000年04月01日 [査読無し][通常論文]
     
    Sequestration of liquid CO2 into intermediate depth ocean has been considered as a means to reduce atmospheric concentration of this greenhouse gas and to mitigate global warming. The dissolution behavior of CO2 into pure/sea water was investigated under conditions in the intermediate ocean, that is, high pressure and low temperature. In these conditions, the CO2 clathrate hydrate film was formed at the interface between CO 2, and (sea) water. The hydrate film has been considered to affect and decrease the dissolution rate.
    In the experiments, LIF technique was used. LIF intensity showed pH of CO2 dissolved water. Therefore, we could know the dissolution rate of CO2 and the non-uniform two dimensional CO2 concentration distribution during the CO2 dissolution with or without the hydrate film in pure/sea water.
    The dissolution rate was faster in pure water than in sea water. The dissolution rate with the hydrate became about half of that without hydrate both in case of pure/sea water.
  • 成田 英夫, 海老沼 孝郎, 内田 努 触媒 41 (7) 542 -546 1999年10月10日 [査読無し][通常論文]
  • 海老沼 孝郎, 内田 努, 成田 英夫 北海道工業技術研究所報告 (73) 1 -6 1999年03月 [査読無し][通常論文]
  • 内田 努, 海老沼 孝郎, 成田 英夫 日本結晶成長学会誌 25 (3) A145 1998年07月 [査読無し][通常論文]
     
    In-situ observations of formation and dissociation processes of CO_2 hydrates were carried out in a liquid CO_2 and water system by using a Mach-Zehnder interferometer. Since the hydrate crystal is transparent, the interferometric method is useful to measure the change of Physical properties of both the hydrate crystal and the environment during the formation and growth Processes. The shift of the fringe provided that the formation heat increased the temperature of liquid CO_2, and the refraction index of CO_2 hydrates were 0.03% greater than that of water.
  • 内田 努, 平野 貴史, 前 晋爾 北海道工業技術研究所報告 (71) 38 -43 1998年03月 [査読無し][通常論文]
  • 内田 努 化学工学 62 (1) 49 -49 1998年01月05日 [査読無し][通常論文]
  • 内田 努, 海老沼 孝郎, 吉田 諒一, 平野 貴史, 前 晋爾, 石崎 武志 資源・素材 1997 (4) 241 -244 1997年09月01日 [査読無し][通常論文]
  • 内田 努, 海老沼 孝郎, 河端 淳一, 吉田 諒一 日本結晶成長学会誌 24 (2) 192 -192 1997年07月01日 [査読無し][通常論文]
     
    In-situ observations of formation and growth processes of C0_2 hydrate crystal were carried out in a liquid C0_2 and water system by using a Mach-Zehnder interferometer. Since the hydrate crystal is transparent, the interferometric method is useful to measure the growth process and physical properties of the hydrate crystal. The shift of interference fringes between C0_2 dissolved water and C0_2 hydrate crystal provided the difference of refractive indices of these phases.
  • 海老沼 孝郎, 内田 努, 成田 英夫, 河端 淳一, 吉田 諒一 日本結晶成長学会誌 24 (2) 193 -193 1997年07月01日 [査読無し][通常論文]
     
    Gas hydrates are going to bc looked at with a keen interest in industrial applications as well as energy and environmentai problems. Various growth behaviors of gas hydrates were observed by using a pressure vessel, even though growth conditions were almost same. A new thermobalance was developed to study the growth process at low temperatures and high pressures.
  • 伊藤 英之助, 堀川 信一朗, 河村 雄行, 内田 努, 本堂 武夫, 前 晋爾 日本結晶成長学会誌 24 (2) 195 -195 1997年07月01日 [査読無し][通常論文]
     
    Molecular dynamics simulations of clathrate hydrate have been performed to investigate the dynamic behavior of C0_2 and CH_4 molecules in the cage. Taking advantage of the KKY potential model used in the present simulations, we obtained the intramolecular vibrational spectra from the Fourier transform of the velocity autocorrelation function. We found the spectral difference between intramolecular vibrations for C0_2 and CH_4 molecules in the large cage and those in the small cage. We discuss these spectral difference compared with the experimental results.
  • 竹谷 敏, 内田 努, 郷原 一寿, 本堂 武夫 日本結晶成長学会誌 24 (2) 235 -235 1997年07月01日 [査読無し][通常論文]
     
    In-situ observations of gas hydrates by x-ray diffraction have been difficult because of the conditions growing under high pressure.Using the high-energy x-ray generator and the high pressure cell made of Al alloy, we made them possible. As a result, we observed the change of profiles from water to C0_2 hydrate.
  • 内田 努 日本エネルギー学会誌 = Journal of the Japan Institute of Energy 76 (5) 362 -370 1997年05月20日 [査読無し][通常論文]
  • 竹谷 敏, 内田 努, 本堂 武夫 日本物理学会講演概要集 52 (1) 105 -105 1997年03月17日 [査読無し][通常論文]
  • 内田 努, 高木 哲史, 河端 淳一 北海道工業技術研究所報告 (69) 41 -44 1997年03月 [査読無し][通常論文]
  • 内田 努, 島田 亙, 本堂 武夫 北海道工業技術研究所報告 (69) 49 -53 1997年03月 [査読無し][通常論文]
  • 内田 努, 平野 貴史, 前 晋爾, 成田 英夫 地質學雜誌 102 (11) 983 -988 1996年11月15日 [査読無し][通常論文]
  • 前野 紀一, 古川 義純, 河田 脩二, 竹井 巌, 内田 努 雪氷 58 (6) 493 -497 1996年11月01日 [査読無し][通常論文]
  • 内田 努, 本堂 武夫 月刊地球 18 (10) 679 -684 1996年10月 [査読無し][通常論文]
  • 内田 努 雪氷 58 (5) 425 -427 1996年09月05日 [査読無し][通常論文]
  • SATOH Kouichi, UCHIDA Tsutomu, HONDOH Takeo, MAE Shinji Proceedings of the NIPR Symposium on Polar Meteorology and Glaciology 10 73 -81 1996年09月 
    Diffusion coefficients and solubility of helium, neon and argon gases in ice crystals were determined by measuring the pressure rise in a vessel caused by gas emission from an ice sample supersaturated with the gas. Diffusion coefficients of helium, neon and argon gases in the temperature range between 258.2 K and 268.2 K were on the order of (10)^<-9>m^2s^<-1>, (10)^<-10>m^2s^<-1> and (10)^<-11>m^2s^<-1>, respectively. Solubilities of helium and neon gases in the molar fraction deduced from the total amount of emitted gases were on the order of (10)^<-6> and (10)^<-7>, respectively. As the diffusion coefficients of noble gases were found to depend on their molecular radii, the diffusion coefficients of air molecules, such as nitrogen and oxygen, in ice were estimated.
  • 内田 努, 成田 英夫, 河端 淳一 日本結晶成長学会誌 23 (3) 135 -135 1996年07月10日 [査読無し][通常論文]
  • 内田努 雪氷 58 (5) 42 -57 1996年
  • 内田 努, 河端 淳一 日本結晶成長学会誌 22 (3) 196 -196 1995年07月10日 [査読無し][通常論文]
  • 内田 努 伝熱研究 = News of HTSJ 35 (134) 52 -57 1995年07月01日 [査読無し][通常論文]
  • 内田 努 雪氷 57 (2) 173 -174 1995年06月15日 [査読無し][通常論文]
  • UCHIDA Tsutomu, MAE Shinji, HONDOH Takeo, LIPENKOV Vladimir Ya., DUVAL Paul, KAWABATA Junichi Proceedings of the NIPR Symposium on Polar Meteorology and Glaciology 8 140 -148 1994年11月 
    Geometrical parameters of air-hydrate crystals in Vostok ice cores revealed that air-hydrate crystals were growing in the deep ice sheet. Air-hydrate crystals with radius of 65 to 100μm grew while smaller crystals dis-appeared. Moreover, the smaller the crystal was, the quicker its number concen-tration decreased. A growth model of air-hydrate crystals in ice sheets was developed by assuming the spherical diffusion field of gas molecules and their steady state diffusions. The model with the given geometrical parameters gave an estimate that the product of the diffusion coefficient and equilibrium concen-tration of gas molecules in ice is of order 10^<-19> m^2 s^<-1> under the conditions of the deep ice sheet. This estimate is reasonable if the concentration of gas molecules in ice is assumed to be the same as that of self-interstitial of ice. The results indicate that gas molecules could diffuse several tens of centimeters during 100 kyr.
  • SATOH Kouichi, UCHIDA Tsutomu, HONDOH Takeo, MAE Shinji Proceedings of the NIPR Symposium on Polar Meteorology and Glaciology 8 207 -207 1994年11月 
    Measurements of diffusion coefficients of He gas and N_2 gas in ice crystals were carried out under the high pressure and atmosphere pressure. The understanding of diffusion phenomena of air molecules in ice is important on studying palaeo-environments by polar ice core analysis. But the measurements of gas molecules diffusion in ice have been done only for He and Ne. Thus we developed an apparatus to measure the diffusion coefficient of gas molecules in ice. In order to estimate the accuracy of this apparatus, the diffusion coefficient of He gas is measured. Measurements of N_2 gas, which is the main constituent of air, were carried out. The diffusion coefficients were measured by the change of gas pressure in the sample cell. In this study a precise differential pressure transducer was used for measuring the small pressure change under high pressure caused by the diffusion of gas molecules in ice samples. All measurements were carried out at 263 (±0.1) K. The diffusion coefficients of He gas molecules in an ice single crystal are 1.5 (±0.6)×(10)^<-5> and 1.6(±1.0)×(10)^<-5>(cm)^2/s at 47.5 and 69.5 atm, respectively. Under atmosphere pressure, it is 1.9 (±0.6)×(10)^<-5>(cm)^2/s. These results agree with the results obtained by J HAAS et al. (Solid State Commun., 9,2033,1971). Therefore it is estimated that this apparatus can measure diffusion coefficients of more than about (10)^<-6>(cm)^2/s. The diffusion coefficient of N_2 gas molecules in an ice polycrystal is 1 (±1)×(10)^<-6>(cm)^2/s, at atmosphere pressure. In a single crystal of ice it cannot be measured. N_2 gas molecules can be considered to diffuse with less than (10)^<-6> (cm)^2/s of diffusion coefficient in a ice single crystal. These results indicate that N_2 gas molecules in ice diffuse along grain boundaries faster than in the lattice. The obtained diffusion coefficient of N_2 gas also indicates that air molecules in a deep ice sheet can be estimate to diffuse about 20 m during 100 kyr if they diffuse only along grain boundaries.
  • Uchida Tsutomu, Hondoh Takeo, Mae Shinji, Shoji Hitoshi, Azuma Nobuhiko Memoirs of National Institute of Polar Research. Special issue 49 306 -313 1994年03月 
    Experimental data on the dissociation rate of air-hydrate crystals in Vostok cores, Antarctica, and Dye-3 cores, Greenland, during their long term storage revealed that dissociation of the crystals affected the volume expansion of deep ice cores. The temperature dependence of the dissociation rate of the air-hydrate crystals determines the optimized storage temperature and the time period for both the transportation of ice cores and their long storage plans. The results also suggest that deep ice cores should be stored in the shape of bulk samples to prevent the from dissociating, including the air-hydrate crystals.
  • Uchida Tsutomu, Mae Shinji, Hondoh Takeo, Duval Paul, Lipenkov Volodya Ya. Proceedings of the NIPR Symposium on Polar Meteorology and Glaciology 7 1 -6 1993年09月 
    Microscopic observations of thin sections of Vostok ice cores, Antarctica, showed that various shapes and sizes of air-hydrate crystals are located on the grain boundaries. The surface energy of air-hydrate crystal was measured on 41 crystals in 7 different depth ice cores. These measurements revealed that the surface energy of air-hydrate was almost constant at all depths below 1050m, and that the average ratio between the surface energy of air-hydrate and ice grain boundary energy was 0.97±0.19. The observations also showed that air-hydrate crystals acted as obstacles for ice grain boundary migration.
  • Uchida Tsutomu, Mae Shinji, Hondoh Takeo, Duval Paul, Lipenkov Volodya Ya. Proceedings of the NIPR Symposium on Polar Meteorology and Glaciology 7 7 -13 1993年09月 
    Microscopic observations of air-hydrate crystals in Vostok ice cores, Antarctica, revealed that air-hydrate crystals acted as obstacles to the grain boundary migration. About half of the air-hydrate crystals were observed to be located on the grain boundaries; their volume concentrations were more than (10)^3 times larger than dust concentration (J. R. PETIT et al., Nature, 326,62,1990). The presence of air-hydrate crystals on grain boundary was considered to reduce effectively the ice grain growth rate. However, air-hydrate crystals did not result in marked changes in grain size associated with climate transitions.
  • Ikeda Tetsuya, Uchida Tsutomu, Mae Shinji Proceedings of the NIPR Symposium on Polar Meteorology and Glaciology 7 14 -23 1993年09月 
    The transformation of air-hydrate crystals from air-bubbles in ice was observed by a microscope at 270K under high hydrostatic pressure between 19.6 and 34.3MPa during the period of 16 days. The number concentration of the air-hydrates formed by the pressurization was measured and was compared with the number concentration of the air-bubbles included. It was found that the transformation rates calculated from these number concentrations increased from 0 s^<-1> at 19.6MPa to 5.4×(10)^<-9> s^<-1> at 34.3MPa. The transformation process is discussed in terms of the nucleation theory of the crystal.
  • 内田 努, 加藤 康明, 前 晋爾, 本堂 武夫, 河端 淳一 日本結晶成長学会誌 20 (2) 86 -86 1993年07月10日 [査読無し][通常論文]
  • 内田 努 日本地質学会学術大会講演要旨 100 196 -197 1993年03月25日
  • 本堂 武夫, 内田 努 低温科学. 物理篇 51 (51) 197 -212 1993年03月 [査読無し][通常論文]
     
    氷床コア解析で最近とみにその重要性を増している空気包接水和物について,その基本的な性質を解説し,氷床における生成過程を理論的に検討する。特に,生成に伴う拡散過程と空気組成気体の分布について考察する。
  • 本堂 武夫, 内田 努, 前 晋爾, Duval P, Lipenkov V.Ya 南極資料 36 (2) 268 -278 1992年07月 [査読無し][通常論文]
     
    南極ボストークで掘削された深層ボーリング・コアの解析, 特にクラスレート水和物の解析について, その方法と今後の解析計画を紹介する。クラスレート水和物は, 水分子を骨格として, 空気を分子レベルで取り込んだ結晶であり, 氷床深部において気泡の消失と共に出現する。本稿では, X線回折およびラマン散乱の測定によって明らかにされたクラスレート水和物の結晶学的構造を説明すると共に, 氷床におけるその生成過程を考察する。また, 気候変動との関連におけるクラスレート水和物の重要性, ならびにその解析が新たなコア解析手法として, どんな情報をもたらすかについて現時点での知見を基に説明する。
  • 内田 努 化学と工業 = Chemistry and chemical industry 45 (7) 1313 -1314 1992年07月01日 [査読無し][通常論文]
  • 内田 努, 前 晋爾, 本堂 武夫, Duval P, Lipenkov V.Ya 日本結晶成長学会誌 19 (1) 135 -135 1992年06月25日 [査読無し][通常論文]
  • UCHIDA Tsutomu, HONDOH Takeo, MAE Shinji, KAWABATA Jun-ichi Proceedings of the NIPR Symposium on Polar Meteorology and Glaciology 5 182 -182 1992年02月 
    Recently, a strong correlation between the concentration profile of carbon dioxide and climatic change was found by the chemical analysis of deep ice cores recovered from Vostok, Antarctica (J. JOUZEL et al., Nature, 329,403,1987). For further analysis of the CO_2 profile, however, atomic processes of the CO_2 molecules in the ice sheet have to be taken into account, because CO_2 content in air bubbles may differ from its initial value owing to molecular diffusion in ice during the densification process in the ice sheet. In order to clarify the process quantitatively, the dissolution volume and the diffusion coefficient of CO_2 molecules in ice crystal were measured in the present study. A single crystal of ice sample was annealed under high CO_2 gas pressure at about 270K. The gas pressure in the chamber decreased with time and reached a stable value when the ice crystal was saturated with the gas. The equilibrium dissolution volume and the diffusion coefficient of CO_2 into ice crystal were calculated from this measurement. Subsequently, the outer diffusion of CO_2 molecules from the gas saturated sample was also studied. The quantities of CO_2 dissolved in ice at about 270K and 1MPa (which correspond to the conditions at about 100m of depth in temperate glacier) are below 5×(10)^<-4> (mole (cm)^<-3> of ice), which is smaller than that in water at 293K. The diffusion coefficient of CO_2 in ice is of the order of (10)^<-7> ((cm)^2s^<-1>) at about 270K, which is two orders in magnitude smaller than that of water molecules moving through ice lattice. The influence of the quantity dissolved and the diffusion rate of carbon dioxide in the ice on the CO_2 profile obtained from ice cores is discussed.

書籍等出版物

  • 日本のガスハイドレート研究の歩み～黎明期から最先端まで～
    一社, 日本エネルギー学会, 天然ガス部会, 資源分科会, GH 研究会編集委員会 (担当:編者(編著者)範囲:編集委員長、分担執筆：p. 7～22、39～42、75～77)
    日本工業出版（株） 2020年09月
  • Fossil Fuels
    増田昌敬, 内田 努, 長久保定雄, 佐藤幹夫 (担当:分担執筆範囲:Vol. 1, Chapter 10, Methane Hydrates)
    World Scientific Pub. Co. Pte. Ltd. 2017年06月 (ISBN: 9789814699976)
  • 低温科学便覧
    内田 努 (担当:分担執筆範囲:氷と雪の基礎科学)
    丸善出版（株） 2015年10月
  • 非在来型天然ガスのすべて エネルギー資源の新たな主役（コールベッドメタン・シェールガス・メタンハイドレート）
    内田 努 (担当:編者(編著者)範囲:編集委員会副委員長、分担執筆)
    日本工業出版 2014年05月
  • 新版 雪氷辞典
    内田 努 (担当:編者(編著者)範囲:物性部門編集、分担執筆)
    古今書院 2014年
  • Bio-Nanotechnology: A Revolution in Biomedical Sciences, & Human Health
    内田 努 (担当:分担執筆範囲:Chapter 29: Basic Characterization of Nanobubbles and Its Potential Applications)
    John Wiley & Sons, Ltd. 2013年02月
  • Crystal Growth, Book 2
    内田 努 (担当:分担執筆範囲:Chapter 9: Freezing properties of disaccharide solutions: inhibition of hexagonal ice crystal growth and formation of cubic ice)
    InTech 2012年01月
  • International, Symposium on the Physics, Chemistry of Ice, 古川 義純, 佐崎 元, 内田 努, Watanabe Naoki 
    Hokkaido University Press 2011年 (ISBN: 9784832903616) xi, 472 p.

講演・口頭発表等

  • マイクロ・ナノバブルの観測と結晶化促進効果  [招待講演]
    内田 努
    極限コヒーレント光科学セミナー 2018年12月 公開講演，セミナー，チュートリアル，講習，講義等
  • Xenon plays inhibition roles on the neuronal network activities  [招待講演]
    T. Uchida, K. Shimada, R. Tanabe, T. Kubota, D. Ito, K. Yamazaki, K. Gohara
    2nd International Aquaphotomics Symposium, 2016年11月 口頭発表（一般）
  • トレハロースの氷晶成長抑制機構～水溶液の凍結過程と凍結保護作用の観測～  [招待講演]
    内田 努
    第20回トレハロースシンポジウム 2016年11月 ポスター発表
  • １．農産物や食品の低温保存技術への応用技術seeds;「水溶液の凍結制御技術」「（2）ナノバブルによる結晶化促進効果」  [招待講演]
    内田 努
    グリーンテクノバンクUnmet needsワークショップ 2016年10月 シンポジウム・ワークショップパネル（指名）
  • トレハローストランスポーターを発現したCHO-K1細胞の凍結保条件  [招待講演]
    内田 努, 古川真帆, 黄川田隆洋, 山崎憲慈, 郷原一寿
    2015年10月 口頭発表（一般）
  • ガスハイドレート溶解時のナノバブル発生と再結晶化過程におけるメモリー効果  [招待講演]
    内田 努, 山崎憲慈, 郷原一寿
    日本地球惑星科学連合2015年大会 2015年05月 シンポジウム・ワークショップパネル（指名）
  • 氷を制御して生物の活性を制御する  [招待講演]
    内田 努
    2014年度雪氷物性分科会シンポジウム 2014年09月 シンポジウム・ワークショップパネル（指名）
  • 生物の中の水を制御する  [招待講演]
    内田 努
    鮮度保持技術に関する意見交換会 2014年08月 シンポジウム・ワークショップパネル（指名）
  • Analysis and control of cultured neuronal networks using multi-electrode arrays: from gene expression to network dynamics  [招待講演]
    D. Ito, K. Yokoyama, T. Uchida, K. Gohara
    IVth Int. Conf. Topical Problems in Biophotonics 2013 2013年07月 口頭発表（招待・特別）
  • トレハロースの氷晶成長抑制機構～水溶液の凍結過程と凍結保護作用の観測～  [招待講演]
    内田 努
    第16回トレハロースシンポジウム 2012年10月 シンポジウム・ワークショップパネル（指名）
  • Gas Structured Water: From Gas Hydrates to Cellular Activity Inhibition  [招待講演]
    内田 努
    WINPTech2011, “Water and Light” session 2011年12月 シンポジウム・ワークショップパネル（指名）
  • 混合ガスハイドレートの分解挙動の組成依存性  [招待講演]
    内田 努
    第６回GHIC講演会 2011年01月 公開講演，セミナー，チュートリアル，講習，講義等
  • 凍結割断レプリカ法による糖の凍結抑制作用の観測  [招待講演]
    内田 努
    平成22年度日本顕微鏡学会北海道支部学術講演会 2010年12月 口頭発表（招待・特別）
  • トレハロース水溶液凍結時に観測された氷Ic結晶相の形成過程  [招待講演]
    内田 努
    日本物理学会2010年秋季大会・領域9，12合同シンポジウム 2010年09月 シンポジウム・ワークショップパネル（指名）
  • マイクロ・ナノバブルの電子顕微鏡観察  [招待講演]
    内田 努
    農林水産・食品産業マイクロ・ナノバブル技術研究組合平成22年度通常総会講演会 2010年05月 公開講演，セミナー，チュートリアル，講習，講義等
  • 氷・クラスレートハイドレートの透過型電子顕微鏡観測  [招待講演]
    内田 努
    平成21年度日本顕微鏡学会北海道支部学術講演会 2009年12月 口頭発表（招待・特別）
  • ガスハイドレートの形成過程と水溶液の構造化  [招待講演]
    内田 努
    日本分析化学会第58回年会 2009年09月 口頭発表（招待・特別）
  • 水の構造化 ―クラスレートハイドレートから細胞へ―  [招待講演]
    内田 努
    2006年度第6回水科学研究会 2006年12月 シンポジウム・ワークショップパネル（指名）

所属学協会

  • 日本熱物性学会   日本顕微鏡学会   低温生物工学会   日本生物物理学会   日本エネルギー学会   日本結晶成長学会   日本雪氷学会   

共同研究・競争的資金等の研究課題

  • 細胞内水の状態観測による凍結保存メカニズムの再検討
    日本学術振興会：科学研究費助成事業 挑戦的研究(萌芽)
    研究期間 : 2022年06月 -2025年03月 
    代表者 : 内田 努
  • 細胞凍結保存の高度化技術開発
    （国研）科学技術振興機構（JST）：研究成果展開授業研究成果最適展開支援プログラム（A-STEP）機能検証フェーズ試験研究タイプ
    研究期間 : 2019年09月 -2021年03月 
    代表者 : 内田 努
  • 抗氷核活性を利用した農産物の品質保持や凍結制御の技術開発
    北海道大学：ロバスト農林水産工学研究プログラム
    研究期間 : 2019年05月 -2020年03月 
    代表者 : 荒川 圭太
  • ガスハイドレートの再生成過程促進に係るウルトラファインバブルの効果
    （公財）東燃ゼネラル石油研究奨励・奨学財団：第38回（2018年度）研究助成
    研究期間 : 2019年04月 -2020年03月 
    代表者 : 内田 努
  • 日本学術振興会：科学研究費助成事業 新学術領域研究(研究領域提案型)
    研究期間 : 2014年07月 -2019年03月 
    代表者 : 郷原 一寿, 山崎 順, 塩谷 浩之, 坂口 紀史, 内田 努, 山崎 憲慈, 前原 洋祐
     
    本研究課題では、活性サイトを原子分解能で明らかにするために、ナノ構造体を電子顕微鏡によりイメージングするための方法論の開拓と応用を目的に研究を展開した。【課題１】では、電子回折を用いるイメージングの高度化と応用のための実験手法の構築を進めた。【課題２】では、複数のナノ構造体に対して構造と機能に関する重要な結果が得られた。【課題３】では、グラフェン上ナノ構造体の３次元原子分解能イメージングに関する研究を進め、白金単原子を凝集することなく分散させることに成功し、原子配置と電子状態を解明した。原子、分子、クラスタのグラフェン上活性サイトに関して新たな知見を得た。
  • 抗氷核活性を利用した農産物の品質保持や凍結制御の技術開発
    北海道大学：ロバスト農林水産工学研究プログラム
    研究期間 : 2018年10月 -2019年03月 
    代表者 : 荒川 圭太
  • 日本学術振興会：科学研究費補助金 挑戦的研究（萌芽）
    研究期間 : 2017年07月 -2019年03月 
    代表者 : 内田 努
     
    本研究は、通常細胞内へ入らないトレハロースが細胞内に入った時高い凍結保護効果を示す要因について、トレハロース輸送タンパク質(TRET1)を発現させた細胞と発現させない通常の細胞とを用いて、実験的に明らかにすることを目標とした。従来細胞内水がトレハロースによりガラス化していると考えられていたが、粉末X線回折や示差熱量測定の結果は主に氷Ih結晶の存在を示唆しており、THz分光の結果は氷点下で液体相の存在の可能性を示す温度帯があることがわかった。今後はこれらの計測手法による詳細な検討が必要である。
  • 第9回国際ガスハイドレート会議（ICGH9）
    （一財）向科学技術振興財団：平成28年度国際交流（派遣）助成金
    研究期間 : 2017年06月 -2017年07月 
    代表者 : 内田 努
  • 農林水産系のファインバブル技術開発
    総合科学技術・イノベーション会議：戦略的イノベーション創造プログラム（次世代農林水産業創造技術）
    研究期間 : 2014年10月 -2017年03月 
    代表者 : 内田 努
  • ニューラルネットワークの信号伝達がガス分子によって抑制される機構の解明
    科学研究費補助金事業
    研究期間 : 2011年04月 -2014年03月 
    代表者 : 内田 努
  • 文部科学省：科学研究費補助金(挑戦的萌芽研究)
    研究期間 : 2013年 -2014年 
    代表者 : 内田 努
     
    本研究は、1ミクロン以下の微細気泡（NB）の産業利用のために、NBが充分な寿命を持っていることを確認し、その寿命を延ばす要因をNBとその周囲の溶質の物性計測と形態学的観察から明らかにすることを目的とする。平成25年度は、基準となる試料作成および計測技術の確立を目指し、以下の項目について実施した。I. 新規ミクロスコピック計測：純水及び酸素からNB含有水溶液を生成し、凍結割断用の試料を作成するまでの時間を変化させながら作成した。NB含有水溶液作成後0～7日後に、水溶液試料の一部を液体窒素雰囲気下で急速凍結し、低温・高真空条件下にて割断、白金と炭素を蒸着させることで電子顕微鏡観測用レプリカを作成した。作成したレプリカ試料を電子顕微鏡にて観察した結果、500nm以下の円形～楕円形の穴が多く観察された。NBを含有しない純水を用いたコントロール試料ではこのような穴はほとんど観察されないことから、この穴が酸素NBに対応するものと判断した。作成後0～1日後の試料に比べ、4日以上たった水溶液の試料からはNBの含有量が少なくなっていることが観察され、純水中での酸素NBの寿命は数日程度であることが示唆された。II. 従来型マクロスコピック計測：Iで作成した試料の一部を生成直後より光散乱法にて測定し、水溶液試料中の気泡の量や大きさの分布の経時変化を観測した。気泡の大きさ分布とレプリカの電子顕微鏡観察で測定された気泡分布等とを比較して、新規計測法と従来型計測法による定量計測結果の整合性の確認と、試料の作成条件と気泡の安定性との関係とを調べた。その結果、I.で開発した電子顕微鏡画像から得られる情報は、従来用いられている光散乱測定と同程度のデータが得られることを確認した。
  • メタンハイドレートの科学技術開発に関する国際会議
    北海道大学：総長室事業推進経費（公募型プロジェクト研究等支援経費）「国際研究集会等開催支援」
    研究期間 : 2011年08月 -2013年03月 
    代表者 : 内田 努
  • 文部科学省：科学研究費補助金(基盤研究(B))
    研究期間 : 2011年 -2013年 
    代表者 : 内田 努, 郷原 一寿, 永山 昌史
     
    キセノン(Xe)ガスによるニューラルネットワークの信号伝達抑制機構を解明するため、二つの側面から観測を行った。培養ニューラルネットワークの電気信号を、Xeガスを0.1～0.5Mpaまで印加した状態で測定した結果、0.3MPa以上の圧力下でネットワーク特有な信号が完全に抑制された（メゾスコピック観察）。またXeガス加圧下でのニューロンのラマン分光観測を行い、その信号変化を観測した。計算機シミュレーションとの比較から、細胞膜にXeガスが溶解しその機能を変化させる可能性を見出した（マイクロスコピック観察）。これらの結果から、Xeがニューラルネットワーク中の信号伝達を抑制するメカニズムを検討した。
  • マイクロ・ナノバブルの形態と安定性に関する研究
    （財）前川報恩会：平成23年度第2回学術研究助成事業
    研究期間 : 2011年09月 -2012年03月 
    代表者 : 内田 努
  • 日本学術振興会：科学研究費助成事業 基盤研究(A)
    研究期間 : 2008年 -2011年 
    代表者 : 郷原 一寿, 内田 努, 永山 昌史, 塩谷 浩之
     
    時間的には約10桁、空間的には約3桁に渡る極めて広いマルチスケールな時空間ニューロダイナミクスの計測と制御を行うことを目標に、多電極アレイ上で神経細胞を長期に渡って培養し、インパルスの信号検出およびネットワークの形成過程の観察を行う実験手法を構築し、得られたデータの解析を行うこと目的とした。その結果、多電極アレイ上で、ほぼ安定して数ヶ月以上の長期に渡る神経細胞培養の手法を確立した。また、培養したニューラルネットワークから、長期間連続して、インパルスが計測できるシステムを構築し、さらに、免疫蛍光染色によって、数ヶ月に渡ってネットワークの成長過程を、ニューロンの主要構成要素の変化として計測できる手法を確立した。ニューラルネットワークの基本問題に取り組むためのウェットな実験的研究基盤を独自に構築することが一つの大きな目標であったが、本研究で目的とした実験系の構築は達成され、さらにそれを適用し、重要な結果が得られた。本研究によって構築されたシステムおよび方法に対して、さらに改良を加えることで、時空間ニューロダイナミクスの基本的理解・解明と応用への展開が期待できる。
  • ガス印加法による細胞の常温保存技術の開発
    （独）科学技術振興機構（JST）：地域イノベーション創出総合支援事業 重点地域研究開発支援プログラムシーズ発掘試験
    研究期間 : 2009年08月 -2010年03月 
    代表者 : 内田 努
  • 天然ガスハイドレートの焼結現象の観察
    北海道ガス：平成21年度北海道ガス大学研究支援制度
    研究期間 : 2009年07月 -2010年03月 
    代表者 : 内田 努
  • 日本学術振興会：科学研究費助成事業 挑戦的萌芽研究
    研究期間 : 2009年 -2010年 
    代表者 : 郷原 一寿, 内田 努, 永山 昌史
     
    今年度は、研究実施計画に沿って、1.蛍光染色条件の絞り込み、2.既知タンパク質の発現時期同定法、3.ブロッカーによる特定タンパク質のブロック法、4.ニューロダイナミクスの解析法について研究を進めた。1については、抑制性シナプス、興奮性シナプスをそれぞれ、VGluT1、VGATで再現良く染色することを可能とする手法を確立した。2については、ニューロンの核、軸索、樹状突起に加えて、抑制性シナプス、興奮性シナプスのそれぞれに特異的なタンパク質の発現量を2ヶ月の長期に渡って定量的に計測することが可能となった。3については、ピペッティングによるブロッカの注入、インパルス測定、ブロッカの除去、インパルス測定の手順を繰り返すことにより、再現性が保証できる実験条件を、特定タンパク質に対して試みたが、実験回数が十分でなく再現性についての課題が残った。4については、平均発火、同期バースト、リターンマップ、相関などの主要時系列データの解析が可能となった。 研究成果の一部は、多電極アレイに関する最大規模の国際会議(MEA Meeting 2010、ドイツ、参加国数20,2010年7月)において発表され、数多くある候補の中から論文中の蛍光染色イメージの一つが"the most impressive image"としてProceedingの表紙に採択された。また、本研究で得られた1,2,4に関する結果の一部は、同期バーストに必要なネットワークの最小サイズに関する論文(Neuroscience 171,50-61,2010.)においてまとめられた。また、論文中の蛍光染色イメージの一つが、Neuroscience誌(論文の掲載号)の表紙を飾った。
  • ガスハイドレート自己保存効果発現条件の高度化
    ゼネラル石油研究奨励財団：ゼネラル石油研究奨励財団研究助成
    研究期間 : 2008年03月 -2009年03月 
    代表者 : 内田 努
  • 第6回ガスハイドレート国際会議（カナダ国バンクーバー市）
    日本学術振興会：平成20年度国際学会等派遣事業
    研究期間 : 2008年07月 -2008年07月 
    代表者 : 内田 努
  • 第6回メタンハイドレート研究技術開発に係る国際ワークショップ国際ワークショップ（ノルウェー国ベルゲン市）
    池谷科学技術振興財団：研究者海外派遣助成
    研究期間 : 2008年05月 -2008年05月 
    代表者 : 内田 努
  • 細胞内外の水の構造化による細胞活動制御
    科学研究費補助金事業
    研究期間 : 2005年05月 -2008年03月 
    代表者 : 内田 努
  • 日本学術振興会：科学研究費助成事業 基盤研究(B)
    研究期間 : 2005年 -2007年 
    代表者 : 郷原 一寿, 内田 努, 永山 昌史, 塩谷 浩之
     
    複雑系の研究において"階層性の発現"は基本的かつ重要な研究テーマである。本研究では理論的および実験的な課題を設定し研究目的とした。前者は、"切り替えダイナミクスの非線形動力学的解析"である。これは、常微分方程式の確率的切替によって高次元状態空間に形成される軌道集合の特徴について非線形動力学理論による解析を行い、軌道集合の階層構造をマルチフラクタルによって定量化し、さらにこの結果を用いて、相互作用によって時間軸方向と実空間に創出されるフラクタルな時空間階層構造を制御する方法を明らかにすることが課題である。後者は、"可変入力培養神経回路システムの構築と時空間階層構造の計測・制御"である。これは、ニューロンの信号を計測可能な培養神経回路の実験系を構築し、得られた理論的解析結果に基づいてウェットな神経回路に現れるフラクタルな時間的・空間的階層構造の計測法および制御法を確立することを課題とした。 理論的な目的はほぼ達成された。実験的な目的の達成率は十分ではないが、本研究によって、多電極プローブ上で分散培養したニューロンを用いて、ニューラルネットワークの時間と空間のダイナミクスを計測し制御するという研究方向が科学的にも技術的にも大きな可能性を持っていることが明確になってきた。さらに実験システムを充実させることによって、神経回路網が形成される前の初期段階から1カ月後までの発達期、1年におよぶ長期のダイナミクスの時間的・空間的変化の計測と制御を可能とし、理論を展開するためにも必要となるウェットな培養神経回路網の実験系が構築できることを示した。 今後は、構築した実験系を理論家に広く開放して、理論と実験を接続するプラットフォームとし、マルチスケールな時間・空間ダイナミクスに注目した、脳情報処理の新たな研究領域および新しい学問分野を開拓することを目指す。
  • 文部科学省：科学研究費補助金(基盤研究(B))
    研究期間 : 2005年 -2006年 
    代表者 : 内田 努, 郷原 一寿, 永山 昌史
     
    本研究は、神経細胞や心筋細胞、及びそれらの細胞内外に生成される構造化した水を対象として、水が細胞の信号伝達に果たす役割やメカニズムを明らかにすることを目標とした。そのために、1)「細胞ネットワークの信号伝達に及ぼす温度、圧力及び包接水和物生成気体の影響観察」及び2)「細胞間隙において構造化した水の観察技術の開発」という2つの研究課題を設定し実施した。課題1)では、多電極型細胞信号測定装置を導入し、神経細胞、心筋細胞の自発発火信号を計測した。通常培養条件(温度37℃、圧力1気圧、CO_2濃度5%含有空気)における発火状況をコントロールとして、温度、圧力、環境組成を独立に制御した培養条件下における発火状況の変化を観測した。その結果神経細胞および心筋細胞の発火頻度は、常温以下の低温条件下(神経細胞:37〜15^L、心筋細胞:37〜27^L)で減少することが確認された。その温度依存性は可逆であり、ヒステリシスが認められた。また常温時に試料全体で同期拍動していた心筋細胞は、温度の低下とともに拍動の伝播に乱れを生じ、同期する細胞がクラスター化することを見出した。圧力依存性については、心筋細胞において0.5MPa以上の加圧条件下で拍動が抑制されることがわかった。この装置系を用いて、細胞の自発発火信号を測定しながら包接水和物生成気体を導入する試験を開始した。課題2)では細胞および構造化した水を電子顕微鏡で観測する手法を開発するため、トレハロース水溶液のフリーズレプリカ試料の電子顕微鏡観察を行った。この結果サブミクロンサイズの微粒子が観測された。この実体を明らかにするため、クライオトランスファーホルダを用いた透過型電子顕微鏡で直接観測し、氷単結晶試料上に数十nmの微粒子が存在することを確認した。これにより、細胞間隙の構造化水を観測できる可能性が示唆された。また水構造化装置を導入し、包接水和物の直接観測法の開発に着手した。
  • 日本学術振興会：科学研究費助成事業 基盤研究(A)
    研究期間 : 1995年 -1996年 
    代表者 : 前 晋爾, 内田 努, 郷原 一寿, 本堂 武夫, 藤田 秀二
     
    本研究の目的は、将来のエネルギー資源として有望視されているメタンハイドレートの資源利用のため、その物理化学的性質を明らかにすることである。特に、結晶内部のメタン分子の描象を捕らえ、メタンハイドレートの生成・解離機構を明らかにするため、X線回折、ラマン散乱による実験および分子動力学シミュレーションを行なった。また、メタンハイドレートの特性を理解する上で重要である炭酸ガスハイドレート、空気ハイドレートの研究も行なった。 本研究で得られた成果は、次の通りである。 (1)人工メタンハイドレートの結晶構造解析を、X線粉末回折法で測定した。測定して得られた回折線強度は、計算で求めたI型ハイドレートの回折線の相対強度(エチレンオキサイドハイドレート単位胞長は、a=11.96±0.1 4Åと求められた。この結果、測定した人工メタンハイドレートはI型結晶であることが確認された。 (2)メタンハイドレート中の水和数を非破壊で測定するため、人工メタンハイドレート試料について、ラマン分光測定を行った。各ケージへの占有率を熱力学的モデルを用いて見積ったところ、水和数は6.08〜6.28となった。質量測定で得られた見かけの水和数の変化に比べて、見積もられた水和数の変化が小さいことから、この変化の差は試料中のハイドレート含有率として表わされることが示された。また、炭酸ガスハイドレートの生成過程をラマン分光法を用いて観察し、水溶液中で結晶が成長していく際に炭酸ガスの周囲の水分子の構造が変化していく様子を捕らえることができた。 (3)メタンハイドレート結晶中のメタン分子の運動を明らかにするため、分子動力学シミュレーションを行なった。メタン分子の振動スペクトルを計算した結果、液体の状態よりもより速い回転・伸縮振動が起こっていることが明らかになった。また原子の軌跡より、ケージ内でメタン分子は周りからの束縛をほとんど受けずも回転運動をしていることがわかった。炭酸ガスハイドレートについては、結晶中にある大きさの異なる2種類のケージ内でのゲスト分子の運動状態を調べた。振動スペクトルの計算から、小さなケージ内では二酸化炭素分子の分子内伸縮振動数は高く、周囲の水分子からの束縛を受けた運動状態にあることが明らかになった。

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社会貢献活動

  • 北海道札幌啓成高等学校スーパーサイエンスハイスクール運営指導委員会
    期間 : 2013年04月 - 現在
    役割 : 助言・指導
    主催者・発行元 : 北海道札幌啓成高等学校スーパーサイエンスハイスクール
  • 北大総合博物館「卒論ポスター発表会」
    期間 : 2011年 - 現在
    役割 : 助言・指導
    主催者・発行元 : 北大総合博物館
  • メタンハイドレート開発促進事業「環境有識者会議」委員
    期間 : 2009年12月24日 - 2019年03月31日
    役割 : 助言・指導
    主催者・発行元 : エンジニアリング協会

メディア報道

  • 砂層型メタンハイドレートの基礎研究は、本当にもう充分？
    報道 : 2017年
    発行元・放送局 : 青山千春、ワニ・プラス
    番組・新聞雑誌 : 科学者の話ってなんて面白いんだろう
    　その他
  • H2Oを科学する
    報道 : 2015年04月
    発行元・放送局 : 北海道大学アドミッションセンター
    番組・新聞雑誌 : 知のフロンティア
    　会誌・広報誌

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