研究者データベース

遠堂 敬史(エンドウ タカシ)
創成研究機構 ナノテクノロジー連携研究推進室
特任助教

基本情報

所属

  • 創成研究機構 ナノテクノロジー連携研究推進室

職名

  • 特任助教

学位

  • 博士(理学)(北海道大学)

科研費研究者番号

  • 70972305

J-Global ID

職歴

  • 2022年08月 - 現在 北海道大学 創成研究機構 特任助教
  • 2021年04月 - 2022年07月 北海道大学 大学院工学研究院 技術専門職員
  • 2012年04月 - 2021年03月 北海道大学 大学院工学研究院 技術職員

学歴

  • 2013年03月 - 2018年12月   北海道大学   大学院総合化学院   総合化学専攻 (博士・長期履修生)
  • 2009年04月 - 2011年03月   北海道大学   大学院理学院   化学専攻(修士)
  • 2005年04月 - 2009年03月   北海道大学   理学部   化学科 (学士)

所属学協会

  • 日本希土類学会   日本顕微鏡学会   日本セラミックス協会   

研究活動情報

論文

  • Masaki Kato, Ryo Ota, Takashi Endo, Takashi Yanase, Taro Nagahama, Toshihiro Shimada
    ACS APPLIED NANO MATERIALS 5 2 2367 - 2374 2022年02月 
    Covalent organic frameworks (COF) have been gathering much attention because the shapes, sizes, and chemical functions of their nanostructured pores can be arbitrarily controlled by designing the organic precursors. We fabricated cm-sized free-standing COF films with the thickness of 50-100 nm by an alternating vacuum deposition polymerization method. Precise adjustment of the stoichiometry by digitally controlled deposition was essential for producing the robust free-standing COF films. High-resolution electron microscopy revealed 3 nm pore structures, which correspond to the atomic structure of the COF. Small angle X-ray diffraction shows the existence of a similar periodicity. The CO2/N-2 gas phase separation properties were evaluated from 10(3)-10(5) Pa, and the parameters for each molecular permeation were determined. Based on the detailed analysis, it was found that the selectivity comes from the greater sorption affinity of CO2 to the COF compared to N-2, which is consistent with the quantum chemical calculation. Since the vapor phase method can be used to coat various shaped templates, our method provides a new option for fabrication of neat COF membranes with various structures and their applications for the separation membrane.
  • Akira Hosono, Yuji Masubuchi, Shintaro Yasui, Masaki Takesada, Takashi Endo, Mikio Higuchi, Mitsuru Itoh, Shinichi Kikkawa
    INORGANIC CHEMISTRY 58 24 16752 - 16760 2019年12月 
    Perovskite-type oxynitride BaTaO2N has been attracting attention for its large dielectric constant, which is almost independent of the temperature by measurements on its ceramics. Its dielectric characteristics are attributed to polar nanoregions (PNRs) in the average cubic crystal structure. Polarization saturation to produce a butterfly-like piezoresponse force microscopy (PFM) signal was observed on BaTaO2N crystals in the present study. Reddish crystallites of BaTaO2N of up to 3.1 mu m in size were grown using a BaCN2 flux. Grain growth proceeded through the formation of a Ruddlesden-Popper-type oxynitride from the reaction between BaTaO2N powder and molten BaCN2. Their electrical property was studied using PFM with special care because of the small size of the crystals. They were found to be much more highly insulating than its ceramics. Ferroelectricity with complete phase inversion was observed on an oxynitride perovskite crystal for the first time. A large coercivity of 50-60 V was observed in the measurement. Such ferroelectricity is ascribed to the PNRs induced by the polar linkages between cis-type TaO4N2 octahedra.
  • Tomoka Hasegawa, Tomomaya Yamamoto, Hiromi Hongo, Zixuan Qiu, Miki Abe, Takuma Kanesaki, Kawori Tanaka, Takashi Endo, Paulo Henrique Luiz de Freitas, Minqi Li, Norio Amizuka
    HISTOCHEMISTRY AND CELL BIOLOGY 149 4 423 - 432 2018年04月 
    The aim of this study is to demonstrate the application of focused ion beam-scanning electron microscopy, FIB-SEM for revealing the three-dimensional features of osteocytic cytoplasmic processes in metaphyseal (immature) and diaphyseal (mature) trabeculae. Tibiae of eight-week-old male mice were fixed with aldehyde solution, and treated with block staining prior to FIB-SEM observation. While two-dimensional backscattered SEM images showed osteocytes' cytoplasmic processes in a fragmented fashion, three-dimensional reconstructions of FIB-SEM images demonstrated that osteocytes in primary metaphyseal trabeculae extended their cytoplasmic processes randomly, thus maintaining contact with neighboring osteocytes and osteoblasts. In contrast, diaphyseal osteocytes extended thin cytoplasmic processes from their cell bodies, which ran perpendicular to the bone surface. In addition, these osteocytes featured thick processes that branched into thinner, transverse cytoplasmic processes; at some point, however, these transverse processes bend at a right angle to run perpendicular to the bone surface. Osteoblasts also possessed thicker cytoplasmic processes that branched off as thinner processes, which then connected with cytoplasmic processes of neighboring osteocytes. Thus, FIB-SEM is a useful technology for visualizing the three-dimensional structures of osteocytes and their cytoplasmic processes.
  • Akira Hosono, Yuji Masubuchi, Takashi Endo, Shinichi Kikkawa
    DALTON TRANSACTIONS 46 48 16837 - 16844 2017年12月 
    Solid phase sintering of dielectric oxynitride perovskites above 1000 degrees C is accompanied by their decomposition. Post-ammonolysis is required to recover their stoichiometric nitrogen content and dielectric properties. In the present work, the oxynitride perovskite SrTaO2N was sintered with a BaCN2 flux at approximately 900 degrees C avoiding its thermal decomposition. The resulting solid product with a relative density of 68.9% showed relative dielectric constants in the range from 68 to 90 with loss values less than 0.11, without the post-ammonolysis. The interior of the solids contained rectangular Sr1-xBaxTaO2N crystals for which 0.04 <= x <= 0.23 reflecting their euhedral form. These crystals were grown in molten BaCN2 from 20 to 100 times larger than the original SrTaO2N particles and had a maximum grain size of 3.7 mu m. The Sr1-xBaxTaO2N precipitated on the surfaces of the residual SrTaO2N crystals that had partially dissolved in the BaCN2 flux. A compositional gradient from barium-rich to strontium-rich was observed in a single crystal of the product on going from the exterior to the interior. This is the first-ever report of the preliminary liquid phase sintering and crystal growth of a dielectric oxynitride perovskite using a molten metal cyanamide.
  • Hongyu Fan, Takashi Endo, Zhenghua Bi, Weibin Yan, Somei Ohnuki, Qi Yang, Weiyuan Ni, Dongping Liu
    JOURNAL OF NUCLEAR MATERIALS 486 191 - 196 2017年04月 
    Both conductive atomic force microscopy (CAFM) and transmission electron microscopy have been used to characterize the defects or He bubbles in low-energy (120 eV) H and He irradiated tungsten (W). By a comparative study, we find that the current mapping from CAFM is very sensitive in the detection of nanometer-sized defects in low-energy H and He irradiated W. Our calculation confirms that the resistance change in H and He irradiated W is strongly affected by the distance between atomic force microscopy tip and defects/He bubbles. CAFM can accurately detect defects/He bubbles in the W surface layer, however, it is infeasible to measure them in the deep layer (>20 nm), especially due to the existence of defects in the surface layer.(C) 2017 Elsevier B.V. All rights reserved.
  • Takashi Endo, Yoshihiro Doi, Makoto Wakeshima, Keita Suzuki, Yasutaka Matsuo, Keitaro Tezuka, Takuya Ohtsuki, Yue Jin Shan, Yukio Hinatsu
    INORGANIC CHEMISTRY 56 5 2459 - 2466 2017年03月 
    The synthesis, crystal structures, photoluminescence, and magnetic properties of the melilite-type oxysulfide Sr2MnGe2S6O were investigated. This compound crystallizes in the melilite structure with space group P4 ($) over bar2(1)m, in which two kinds of anions, S2- and O2-, occupy different crystallographic sites in an ordered manner. The temperature dependence of the magnetic susceptibility of Sr2MnGe2S6O shows a broad peak due to a two-dimensional magnetic interaction between Mn ions in the ab plane. The specific heat data show that this compound has an antiferromagnetic transition temperature (T-N = 15.5 K) that is much higher than that of the oxide analogue Sr2MnGe2O7 (T-N = 4.4 K). DFT calculations showed that the magnetic interaction is enhanced by covalency in the Mn-s bonding.
  • Tomoka Hasegawa, Takashi Endo, Erika Tsuchiya, Ai Kudo, Zhao Shen, Yasuhito Moritani, Miki Abe, Tomomaya Yamamoto, Hiromi Hongo, Kanako Tsuboi, Taiji Yoshida, Tomoya Nagai, Naznin Khadiza, Ayako Yokoyama, Paulo Henrique Luiz de Freitas, Minqi Li, Norio Amizuka
    JOURNAL OF ORAL BIOSCIENCES 59 1 55 - 62 2017年02月 
    Objectives: The aim of this study was the biological application of focused ion beam-scanning electron microscopy (FIB-SEM) to obtain serial sectional images of skeletal tissues that showed the ultrastructure of 1) cartilaginous extracellular fibrils and 2) osteoblastic cytoplasmic processes.Methods: Seven-week-old female wild-type mice were fixed with half-Karnovsky solution and then OsO4, and tibiae were extracted for block staining prior to observation under transmission electron microscope (TEM) and FIB-SEM.Results: TEM showed the fine fibrillar but somewhat amorphous ultrastructure of the intercolumnar septa in the growth plate cartilage. In contrast, FIB-SEM revealed bundles of stout fibrils at regular intervals paralleling the septa's longitudinal axis, as well as vesicular structures embedded in the cartilaginous matrix of the proliferative zone. In the primary trabeculae, both TEM and FIB-SEM showed several osteoblastic cytoplasmic processes on the osteoid, in greater numbers than those seen in the bone matrix. FIB-SEM revealed the agglomeration of cytoplasmic processes beneath osteoblasts that formed a tubular continuum extending from those cells. Based on these findings, we postulated that osteoblasts not only extend their cytoplasmic processes to the bone matrix, but also stack these cell processes on the osteoid of the primary trabeculae.Conclusion: Taken together, these data suggest that FIB-SEM imaging of serial bone sections may facilitate new insights on the ultrastructure of cartilage and bone tissues. (C) 2016 Japanese Association for Oral Biology. Published by Elsevier B.V. All rights reserved.
  • Kyung Ho Kim, Yuya Yoshihara, Yoshio Abe, Midori Kawamura, Takayuki Kiba, Takashi Endo
    MICROELECTRONIC ENGINEERING 165 20 - 22 2016年11月 
    We investigated the effects of Ni dopant on structural properties of zinc oxide (ZnO) nanorods. All rods had a ZnO hexagonal wurtzite structure. Upon incorporation of Ni in ZnO, the length and width of the nanorods decreased and increased, respectively. Furthermore, the Ni-doped ZnO (Ni-ZnO) nanorods exhibited overall superior crystalline quality and orientation without showing lattice distortion, as determined by XRD (X-ray diffraction) and electron backscattering diffraction (EBSD) analyses. Both rod types had a hydrophilic surface, whilst, the only polar surface energy slightly decreased after Ni doping. (C) 2016 Elsevier B.V. All rights reserved.
  • Wei Xie, Aiko Kawahito, Takuya Miura, Takashi Endo, Yongming Wang, Takashi Yanase, Taro Nagahama, Yukitoshi Otani, Toshihiro Shimada
    CHEMISTRY LETTERS 44 9 1205 - 1207 2015年09月 
    We report the synthesis of a new carbon material diamondlike carbon film codeposited with 1% C-60 molecules by plasma-assisted chemical vapor deposition. The synthesized films exhibited strong iridescent colors after being exposed to an atmosphere containing water vapor. An electron microscopy examination revealed that the film expanded by a factor of more than two, while forming 10-100-nm-sized grain-like structures after its exposure to water vapor. This work demonstrates a new concept of incorporating reaction centers in carbon solids to make carbon-based nanostructures.
  • Kawahito A., Yanase T., Endo T., Nagahama T., Shimada T.
    Journal of applied physics 117 17 17D506 - 17D506 American Institute of Physics (AIP) 2015年05月07日 
    Magnetic nanowires (NWs) are promising as material for use in spintronics and as the precursor of permanent magnets because they have unique properties due to their high aspect ratio. The growth of magnetic Fe whiskers was reported in the 1960s, but the diameter was not on a nanoscale level and the growth mechanism was not fully elucidated. In the present paper, we report the almost vertical growth of Fe NWs on a single crystal yttrium-stabilized zirconia (Y0.15Zr0.85O2) by a thermal CVD method. The NWs show a characteristic taper part on the bottom growing from a trigonal pyramidal nucleus. The taper angle and length can be controlled by changing the growth condition in two steps, which will lead to obtaining uniformly distributed thin Fe NWs for applications.
  • T. Yanase, A. Kawahito, Y. Hashimoto, T. Endo, Y. Wang, T. Nagahama, T. Shimada
    RSC Adv. 4 52 27620 - 27624 2014年 

    The growth mechanism of Fe nanowires and the role of Au nanoparticle catalysis were revealed using transmission electron microscopy and electron diffraction analysis. Fe nanowire has a high aspect ratio and unique [021̄] orientation.

  • Takashi Endo, Yoshihiro Doi, Yukio Hinatsu, Kenji Ohoyama
    INORGANIC CHEMISTRY 51 6 3572 - 3578 2012年03月 
    The crystal structures and magnetic properties of melilite-type oxides Sr2MGe2O7 (M = Mn, Co) were investigated. These compounds crystallize in the melilite structure with space group P (4) over bar2(1)m, in which the M and Ge ions occupy two kinds of tetrahedral sites in an ordered manner. The magnetic M ions form a square-planar lattice in the ab plane. Both compounds do not show the structural phase transition down to 2.5 K. The temperature dependence of magnetic susceptibility for Sr2MnGe2O7 shows a broad peak at similar to 6.0 K because of a two-dimensional magnetic interaction between Mn ions in the ab plane. At 4.4 K, an antiferromagnetic transition was observed. The magnetic structure was determined by the neutron powder diffraction measurement at 2.5 K. It can be represented by the propagation vector k = (0, 0, 1/2), and the magnetic moments of Mn2+ (3.99 mu(B)) ions order antiferromagnetically in a collinear manner along the c axis. On the other hand, Sr2CoGe2O7 shows an antiferromagnetic transition at 6.5 K with divergence between zero-field-cooled and field-cooled susceptibilities. Its magnetic structure determined at 2.5 K has a magnetic propagation vector k = (0, 0, 0), and the ordered magnetic moment of Co2+ (2.81 mu(B)) adopts a collinear arrangement lying on the ab plane.
  • Yayoi Fuwa, Takashi Endo, Makoto Wakeshima, Yukio Hinatsu, Kenji Ohoyama
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 132 51 18020 - 18022 2010年12月 
    The crystal, electronic, and magnetic structures of the cobalt oxyselenide La2Co2O3Se2 were investigated through powder neutron diffraction measurements and band structure calculations. This oxyselenide crystallizes in a tetragonal layered structure with space group 14/mmm. The Co ion is sixfold-coordinated by two oxide ions and four selenide ions, and the face-sharing CoO2Se4 octahedra form Co2OSe2 layers. The band structure calculations revealed that the Co ion is in the divalent high-spin state. Rietveld analysis of the neutron diffraction profiles below 200 K demonstrated that the Co moments have a noncollinear antiferromagnetic structure with the propagation vector k = (1/2, 1/2, 0). The ordered magnetic moment was determined to be 3.5 mu(B) at 10 K, and the directions of the nearest-neighbor Co moments are orthogonal each other in the c plane.
  • Takashi Endo, Yoshihiro Doi, Makoto Wakeshima, Yukio Hinatsu
    INORGANIC CHEMISTRY 49 23 10809 - 10814 2010年12月 
    Synthesis, crystal structures, and magnetic properties of melilite-type oxides A(2)MSi(2)O(7) (A = Sr, Eu; M = Mg, Mn) were investigated. These compounds crystallize in the melilite structure with space group P (4) over bar2(1)m. The Eu-151 Mossbauer measurements show that the Eu ions are in the divalent state. The Eu2MgSi2O7 is paramagnetic down to 1.8 K. Long-range antiferromagnetic ordering is observed at 3.4 K for Sr2MnSi2O7. On the other hand, the Eu2MnSi2O7 shows a ferrimagnetic transition at 10.7 K. From the magnetization and specific heat measurements, it is found that the Eu2+ (14 mu(B)) and Mn2+ (5 mu(B)) sublattices order antiferromagnetically. This result indicates that an interaction between f-d electrons (Eu-Mn) predominantly operate in this compound.

その他活動・業績

受賞

  • 2021年02月 北海道大学 教育研究支援業務 総長表彰 奨励賞
  • 2020年01月 文部科学省 ナノテクノロジープラットフォーム 令和元年度技術スタッフ表彰 若手技術奨励賞
  • 2009年07月 日本化学会北海道支部 2009年夏季研究発表会 優秀講演賞


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