研究者データベース

研究者情報

マスター

アカウント(マスター)

  • 氏名

    AGUS SUBAGYO(アグス スバギヨ), アグス スバギヨ

所属(マスター)

  • 情報科学研究院 情報エレクトロニクス部門 先端エレクトロニクス分野

所属(マスター)

  • 情報科学研究院 情報エレクトロニクス部門 先端エレクトロニクス分野

独自項目

syllabus

  • 2021, 固体物性学特論, Solid State Physics, 修士課程, 情報科学研究科, 状態ベクトル,固有値,固有値方程式,交換関係,期待値,不確定原理,LCAO,摂動法,Van der Waals相互作用,状態ベクトルの時間展開,はいぜんべるぐ方程式,角運動量演算子,空間対称性と保存則,スピン角運動量,波動関数の対称性,交換相互作用,ディラック方程式とスピン,スピン軌道相互作用,トンネル効果,物質内の電子,スピン演算子とハミルトニアンのハイゼンベルグ表示,スピントロニクスの基礎,量子情報処理の基礎
  • 2021, 固体物性学特論, Solid State Physics for Electronics, 修士課程, 情報科学院, 状態ベクトル,固有値,固有値方程式,交換関係,期待値,不確定原理,LCAO,摂動法,Van der Waals相互作用,状態ベクトルの時間展開,はいぜんべるぐ方程式,角運動量演算子,空間対称性と保存則,スピン角運動量,波動関数の対称性,交換相互作用,ディラック方程式とスピン,スピン軌道相互作用,トンネル効果,物質内の電子,スピン演算子とハミルトニアンのハイゼンベルグ表示,スピントロニクスの基礎,量子情報処理の基礎
  • 2021, プロジェクトマネジメント特論, Project Management Basis, 修士課程, 情報科学院, プロジェクトマネジメント 
  • 2021, パーソナルスキル特論, Personal Skills for Project Management, 修士課程, 情報科学院, コミュニケーション,ステークホルダーマネジメント,リーダーシップ,チームビルディング,コンフリクトマネジメント,交渉術,ファシリテーション,アジャイル開発
  • 2021, 固体物性学特論, Solid State Physics, 博士後期課程, 情報科学研究科, 状態ベクトル,固有値,固有値方程式,交換関係,期待値,不確定原理,LCAO,摂動法,Van der Waals相互作用,状態ベクトルの時間展開,はいぜんべるぐ方程式,角運動量演算子,空間対称性と保存則,スピン角運動量,波動関数の対称性,交換相互作用,ディラック方程式とスピン,スピン軌道相互作用,トンネル効果,物質内の電子,スピン演算子とハミルトニアンのハイゼンベルグ表示,スピントロニクスの基礎,量子情報処理の基礎
  • 2021, 固体物性学特論, Solid State Physics for Electronics, 博士後期課程, 情報科学院, 状態ベクトル,固有値,固有値方程式,交換関係,期待値,不確定原理,LCAO,摂動法,Van der Waals相互作用,状態ベクトルの時間展開,はいぜんべるぐ方程式,角運動量演算子,空間対称性と保存則,スピン角運動量,波動関数の対称性,交換相互作用,ディラック方程式とスピン,スピン軌道相互作用,トンネル効果,物質内の電子,スピン演算子とハミルトニアンのハイゼンベルグ表示,スピントロニクスの基礎,量子情報処理の基礎
  • 2021, プロジェクトマネジメント特論, Project Management Basis, 博士後期課程, 情報科学院, プロジェクトマネジメント 
  • 2021, パーソナルスキル特論, Personal Skills for Project Management, 博士後期課程, 情報科学院, コミュニケーション,ステークホルダーマネジメント,リーダーシップ,チームビルディング,コンフリクトマネジメント,交渉術,ファシリテーション,アジャイル開発
  • 2021, 情報学 Ⅰ, Introduction to Informatics I, 学士課程, 全学教育, 情報活用,情報社会,情報科学,プログラミング,データサイエンス
  • 2021, 電気電子工学実験Ⅰ, Electrical and Electronic Engineering Laboratories I, 学士課程, 工学部, バイポーラトランジスタ,増幅回路,MOSFET,CMOS,演算増幅器,論理回路,順序回路,ディジタル回路
  • 2021, 電気電子工学実験Ⅱ, Electrical and Electronic Engineering Laboratories II, 学士課程, 工学部, 偏光,旋光,回折,屈折,結晶構造,X線回折,半導体物性,ホール効果,電気磁気エネルギー,電力
  • 2021, 電気電子工学実験Ⅲ, Electrical and Electronic Engineering Laboratories III, 学士課程, 工学部, 半導体プロセス,MOSFET,集積回路特性評価,SPICE,回路シミュレーション,アセンブリ言語

researchmap

プロフィール情報

所属

  • 北海道大学, 大学院情報科学研究科, 准教授

学位

  • 博士(工学)(北海道大学)

プロフィール情報

  • スバギョ, Subagyo
  • アグス, Agus
  • ID各種

    201501001716379720

所属

  • 北海道大学, 大学院情報科学研究科, 准教授

業績リスト

研究キーワード

  • 薄膜   表面科学   バイオセンサー   カーボンナノチューブ   グラフェン   スピントロニクス   

研究分野

  • ものづくり技術(機械・電気電子・化学工学) / 電子デバイス、電子機器
  • ナノテク・材料 / 薄膜、表面界面物性
  • ナノテク・材料 / ナノ材料科学

経歴

  • 2021年04月 - 現在 北海道大学 大学院情報科学研究院 准教授
  • 2019年04月 - 2021年03月 北海道大学 大学院情報科学研究院 特任准教授
  • 2018年04月 - 2019年03月 北海道大学 創成研究機構 特任助教
  • 2015年04月 - 2018年03月 北海道大学 創成研究機構 博士研究員

学歴

  • 1997年04月 - 2000年03月   北海道大学   大学院工学研究科   電子情報工学専攻 博士後期課程

論文

  • Kohei Etou, Satoshi Hiura, Soyoung Park, Junichi Takayama, Agus Subagyo, Kazuhisa Sueoka, Akihiro Murayama
    Physical Review Applied 19 2 2023年02月21日
  • Kohei Etou, Satoshi Hiura, Soyoung Park, Kazuya Sakamoto, Junichi Takayama, Agus Subagyo, Kazuhisa Sueoka, Akihiro Murayama
    Physical Review Applied 16 1 2021年07月14日 [査読有り]
  • Ryosuke Tanaka, Maki Sawano, Yuki Fujii, Kaori Kuribayashi-Shigetomi, Agus Subagyo, Kazuhisa Sueoka, Takaharu Okajima
    Japanese Journal of Applied Physics 59 SN SN1010 - SN1010 2020年08月01日 [査読有り]
  • Satoshi Hiura, Agus Subagyo, Akihiro Murayama, Kazuhisa Sueoka
    Applied Physics Express 12 5 055502 - 055502 2019年05月01日 [査読有り]
  • Yukiko Miyatake, Kaori Kuribayashi-Shigetomi, Yusuke Ohta, Shunji Ikeshita, Agus Subagyo, Kazuhisa Sueoka, Akira Kakugo, Maho Amano, Toshiyuki Takahashi, Takaharu Okajima, Masanori Kasahara
    Scientific Reports 8 1 2018年12月19日 [査読有り]
     
    Pancreatic ductal adenocarcinoma (PDAC) reportedly progresses very rapidly through the initial carcinogenesis stages including DNA damage and disordered cell death. However, such oncogenic mechanisms are largely studied through observational diagnostic methods, partly because of a lack of live in vitro tumour imaging techniques. Here we demonstrate a simple live-tumour in vitro imaging technique using micro-patterned plates (micro/nanoplates) that allows dynamic visualisation of PDAC microtumours. When PDAC cells were cultured on a micro/nanoplate overnight, the cells self-organised into non-spheroidal microtumours that were anchored to the micro/nanoplate through cell-in-cell invasion. This self-organisation was only efficiently induced in small-diameter rough microislands. Using a time-lapse imaging system, we found that PDAC microtumours actively stretched to catch dead cell debris via filo/lamellipoedia and suction, suggesting that they have a sophisticated survival strategy (analogous to that of starving animals), which implies a context for the development of possible therapies for PDACs. The simple tumour imaging system visualises a potential of PDAC cells, in which the aggressive tumour dynamics reminds us of the need to review traditional PDAC pathogenesis.
  • Qian He, Takaharu Okajima, Hiroaki Onoe, Agus Subagyo, Kazuhisa Sueoka, Kaori Kuribayashi-Shigetomi
    Scientific Reports 8 1 2018年12月14日 [査読有り]
  • PingGen Cai, Ryosuke Takahashi, Kaori Kuribayashi-Shigetomi, Agus Subagyo, Kazuhisa Sueoka, John M. Maloney, Krystyn J. Van Vliet, Takaharu Okajima
    Biophysical Journal 113 3 671 - 678 2017年08月08日 [査読有り]
  • Satoshi Hiura, Akira Ikeuchi, Masafumi Jochi, Riku Yamazaki, Sotaro Takahashi, Agus Subagyo, Akihiro Murayama, Kazuhisa Sueoka
    Applied Physics Express 10 4 045701 - 045701 2017年04月01日 [査読有り]
  • 酸化と酵素切断がLDLの物性に与える影響(Physical properties of low-density lipoprotein after oxidation or proteolytic enzyme treatment)
    Takeda Seiji, Subagyo Agus, Hui Shu-Ping, Fuda Hirotoshi, Sueoka Kazuhisa, Chiba Hitoshi
    生物物理 56 Suppl.1-2 S290 - S290 2016年10月
  • M. Sawano, R. Tanaka, R. Takahashi, K. Kurubayashi-Shigetomi, A. Subagyo, K. Sueoka, T. Okajima
    MOLECULAR BIOLOGY OF THE CELL 27 2016年 [査読有り][通常論文]
  • Seiji Takeda, Agus Subagyo, Shu-Ping Hui, Hirotoshi Fuda, Rojeet Shrestha, Kazuhisa Sueoka, Hitoshi Chiba
    ANNALS OF CLINICAL BIOCHEMISTRY 52 6 647 - 653 2015年11月 [査読有り][通常論文]
     
    Background Evaluation of low-density lipoprotein oxidation is important in the risk assessment of cardiovascular disease. Atomic force microscope is widely used to evaluate the physical properties including stiffness on a single-particle scale. In this study, the effect of low-density lipoprotein oxidation on the low-density lipoprotein stiffness was investigated using an atomic force microscope. Methods Isolated low-density lipoprotein particles with or without oxidation were densely bound to an Au substrate on mica, and then pressed and deformed by the atomic force microscope tip. The stiffness of each low-density lipoprotein particle was estimated as the elastic modulus obtained by the force curve analysis. Biochemical change of low-density lipoprotein due to oxidation was studied by electrophoresis. Results and conclusion The elastic modulus of low-density lipoprotein particles ranged between 0.1 and 2MPa. The oxidation of low-density lipoprotein increased the number of low-density lipoprotein particles with smaller elastic moduli, indicating the decrease in low-density lipoprotein stiffness. The elastic modulus of low-density lipoprotein might be potentially useful to evaluate low-density lipoprotein oxidation.
  • Satoshi Hiura, Akira Ikeuchi, Soraya Shirini, Agus Subagyo, Kazuhisa Sueoka
    JAPANESE JOURNAL OF APPLIED PHYSICS 54 8 08LB02  2015年08月 [査読有り][通常論文]
     
    We report two types of adsorption structures in H/Fe3O4(001) film surfaces and the correlation between OH density and Fe electronic states, which have been studied by scanning tunneling microscopy/spectroscopy (STM/STS). Two types of bright protrusions (BPs), whose lengths along the atomic rows are different, are observed in the STM images. The shorter and longer BPs consist of Fe atoms with one and with two OH groups neighbor, respectively. In addition, STS measurements show the higher local density of states (LDOS) just below the Fermi level of Fe atoms with increasing neighboring OH groups. The variation can be attributed to the difference in the gain of electrons from H atoms, which is due to the difference in the number of neighboring OH groups. These results reveal that surface OH density is a factor for determining the LDOS just below the Fermi level of surface Fe atoms. (C) 2015 The Japan Society of Applied Physics
  • Satoshi Hiura, Akira Ikeuchi, Soraya Shirini, Agus Subagyo, Kazuhisa Sueoka
    PHYSICAL REVIEW B 91 20 205411  2015年05月 [査読有り][通常論文]
     
    We report the presence of OH groups on the surfaces of ultrahigh-vacuum-prepared Fe3O4(001) films by means of x-ray photoelectron spectroscopy (XPS). In addition, the variations of Fe electronic states induced by H atoms adsorbed on a Jahn-Teller distorted Fe3O4(001) surface have been studied using in situ scanning tunneling microscopy and scanning tunneling spectroscopy (STS). The obtained XPS spectra of the films have demonstrated the presence of surface OH groups. The STS spectra measured on Fe sites with and without neighboring OH groups have indicated that adsorbed H and their neighboring Fe atoms behave as electron-donor and electron-trapping sites, respectively. This phenomenon changes the Fe atoms from a semiconducting to a metalliclike nature. These local electronic state modifications are related to the occupation of Fe 3d states just below the Fermi level, corresponding to an Fe2+-like state. The orbital occupation can be explained by the gain of electrons from the adsorbed H atoms.
  • Y. Q. Huang, Y. Puttisong, I. A. Buyanova, X. J. Yang, A. Subagyo, K. Sueoka, A. Murayama, W. M. Chen
    APPLIED PHYSICS LETTERS 106 9 93109  2015年03月 [査読有り][通常論文]
     
    We investigate ensemble electron spin dephasing in self-assembled InGaAs/GaAs quantum dots (QDs) of different lateral sizes by employing optical Hanle measurements. Using low excitation power, we are able to obtain a spin dephasing time T-2* (in the order of ns) of the resident electron after recombination of negative trions in the QDs. We show that T-2* is determined by the hyperfine field arising from the frozen fluctuation of nuclear spins, which scales with the size of QDs following the Merkulov-Efros-Rosen model. This scaling no longer holds in large QDs, most likely due to a breakdown in the lateral electron confinement. (C) 2015 AIP Publishing LLC.
  • Kaori Kuribayashi-Shigetomi, Ryosuke Takahashi, Agus Subagyo, Kazuhisa Sueoka, Takaharu Okajima
    Hyper Bio Assembler for 3D Cellular Systems 57 - 67 2015年01月01日 [査読有り][通常論文]
     
    The compliant mechanical properties of single cells have been extensively investigated and these properties are known to exhibit a strong dependence on the surrounding environments and also cell types, functions and conditions. An understanding of the cell behavior is important for applications of tissue engineering. Accurate rheological measurements are essential to elucidate the mechanisms of cell integrity and fluidity and are also key to mechanically identifying and separating single cells for cellular and tissue engineering. Of the various existing nano-and micro-rheology techniques, atomic force microscopy (AFM) shows great potential as a minimally invasive method. AFM allows mechanical measurements to be performed without the need for chemical modifications, via nano-scale contact between the AFM probe and the cell surface. In this chapter, we describe a recent advance in which micro-fabricated substrates are used for high-speed, automated AFM rheological measurements on size-and position-controlled cells.
  • Takafumi Yamamura, Takayuki Kiba, Xiaojie Yang, Junichi Takayama, Agus Subagyo, Kazuhisa Sueoka, Akihiro Murayama
    JOURNAL OF APPLIED PHYSICS 116 9 94309  2014年09月 [査読有り][通常論文]
     
    The growth-temperature dependence of the optical spin-injection dynamics in self-assembled quantum dots (QDs) of In0.5Ga0.5As was studied by increasing the sheet density of the dots from 2 x 10(10) to 7 x 10(10) cm(-2) and reducing their size through a decrease in growth temperature from 500 to 470 degrees C. The circularly polarized transient photoluminescence (PL) of the resulting QD ensembles was analyzed after optical excitation of spin-polarized carriers in GaAs barriers by using rate equations that take into account spin-injection dynamics such as spin-injection time, spin relaxation during injection, spin-dependent state-filling, and subsequent spin relaxation. The excitation-power dependence of the transient circular polarization of PL in the QDs, which is sensitive to the state-filling effect, was also examined. It was found that a systematic increase occurs in the degree of circular polarization of PL with decreasing growth temperature, which reflects the transient polarization of exciton spin after spin injection. This is attributed to strong suppression of the filling effect for the majority-spin states as the dot-density of the QDs increases. (C) 2014 AIP Publishing LLC.
  • Y. Puttisong, Y. Q. Huang, I. A. Buyanova, X. J. Yang, A. Subagyo, K. Sueoka, A. Murayama, W. M. Chen
    APPLIED PHYSICS LETTERS 105 13 132106  2014年09月 [査読有り][通常論文]
     
    We show that circularly polarized emission light from InGaAs/GaAs quantum dot (QD) ensembles under optical spin injection from an adjacent GaAs layer can switch its helicity depending on emission wavelengths and optical excitation density. We attribute this anomalous behavior to simultaneous contributions from both positive and negative trions and a lower number of photo-excited holes than electrons being injected into the QDs due to trapping of holes at ionized acceptors and a lower hole mobility. Our results call for caution in reading out electron spin polarization by optical polarization of the QD ensembles and also provide a guideline in improving efficiency of spin light emitting devices that utilize QDs. (C) 2014 AIP Publishing LLC.
  • Ryosuke Takahashi, Satoshi Ichikawa, Agus Subagyo, Kazuhisa Sueoka, Takaharu Okajima
    ADVANCED ROBOTICS 28 7 449 - 455 2014年04月 [査読有り][通常論文]
     
    To investigate the mechanical properties of adherent cells under conditions where cell-to-cell interaction can be prevented and controlled, we used microcontact printing to pattern single cells without intercellular contacts and measured them with a custom-built atomic force microscopy (AFM) system. The motorized AFM system can measure individual cells over a large spatial range, enabling the measurement of cells in a microarray format. We tested single fibroblast cells and found that the power-law of their complex shear modulus is not significantly influenced by cell-to-cell contact. This method is effective for obtaining high-throughput measurements on single cells.
  • Ryosuke Takahashi, Kaori Kuribayashi-Shigetomi, Agus Subagyo, Kazuhisa Sueoka, Takaharu Okajima
    生物物理 54 1 S277  一般社団法人 日本生物物理学会 2014年
  • Xinfeng Zhu, Kaori Kuribayashi-Shigetomi, Pinggen Cai, Agus Subagyo, Kazuhisa Sueoka, Takaharu Okajima
    生物物理 54 1 S280  一般社団法人 日本生物物理学会 2014年
  • Takeda Seiji, Subagyo Agus, Hui Shu-Ping, Fuda Hirotoshi, Sueoka Kazuhisa, Chiba Hitoshi
    生物物理 54 1 S149  一般社団法人 日本生物物理学会 2014年
  • PingGen Cai, Ryosuke Takahashi, Kaori Kuribayashi-Shigetomi, Agus Subagyo, Kazuhisa Sueoka, Takaharu Okajima
    2014 INTERNATIONAL SYMPOSIUM ON MICRO-NANOMECHATRONICS AND HUMAN SCIENCE (MHS) 1 - 3 2014年 [査読有り][通常論文]
     
    To sort living cells according to our needs, it is important to understand how degree cell property measured for cell sorting fluctuates in time. Mechanical property of cells is one of essential indicators for cell sorting. Thus, in this study, we attempted to measure a time evolution of viscoelastic property such as complex shear modulus, G* of single cells adhered on substrates using atomic force microscopy (AFM). We observed that the G* largely fluctuated in time even the cells are placed on substrates in a confined condition. This indicates that in mechanical cell sorting, mechanical fluctuations of cells should be carefully estimated so that cells are precisely separated by taking the measured data involving cell fluctuations into account.
  • Ryosuke Tanaka, Yuki Fujii, Junpei Kikkawa, Kaori Kuribayashi-Shigetomi, Agus Subagyo, Kazuhisa Sueoka, Takaharu Okajima
    2014 INTERNATIONAL SYMPOSIUM ON MICRO-NANOMECHATRONICS AND HUMAN SCIENCE (MHS) 1 - 2 2014年 [査読有り][通常論文]
     
    Cells rapidly undergo cell division during the embryogenesis. Such dynamic behaviors of cells during the embryogenesis are considered to be strongly associated with their mechanical properties such as cell-cell mechanical interactions and cell stiffness. However, the interplay between the morphogenesis and the mechanical property of whole cell assembly during the developmental process has not been well understood. To exploring the mechanism of forming the whole cell assembly, we proposed atomic force microscopy (AFM) combined with a microarray technique, which allows us to map mechanical property of the whole cell assembly. In this AFM setup, the cell assembly is randomly directed in the microarray well, and thus the average mechanical property of the whole cell assembly can be reconstructed from mapping images obtained from different cell assemblies.
  • Ryosuke Takahashi, Kaori Kuribayashi-Shigetomi, Agus Subagyo, Kazuhisa Sueoka, Takaharu Okajima
    2014 INTERNATIONAL SYMPOSIUM ON MICRO-NANOMECHATRONICS AND HUMAN SCIENCE (MHS) 1 - 3 2014年 [査読有り][通常論文]
     
    Rheological properties of cells are associated with various cell functions and thus are considered to be an indicator for diagnosing cell disease. Atomic force microscopy (AFM) is a powerful tool for quantifying the mechanical properties of isolated single cells. For example, our AFM technique reported previously revealed that the complex shear modulus of single cells exhibited a large cell-to-cell variation which depended on frequency. By contrast, rheological properties of cell population such as cells in confluent condition have been less understood. Thus, it is valuable to investigate how quantitatively the AFM technique can be applied to cell population such as cells in confluent condition. As a result, rheological properties of cells in confluent conditions can be relatively rapidly measured by our AFM setup modifying a force modulation AFM mode. This suggests that the AFM technique is useful for diagnosing not only single cells but also cell population and cell assembly.
  • HIURA Satoshi, IKEUCHI Akira, SHIRINI Soraya, SUBAGYO Agus, SUEOKA Kazuhisa
    e-Journal Surf Sci Nanotechnol (Web) 12 26-30 (J-STAGE)  2014年 [査読有り][通常論文]
  • Xiao-Jie Yang, Takayuki Kiba, Takafumi Yamamura, Junichi Takayama, Agus Subagyo, Kazuhisa Sueoka, Akihiro Murayama
    APPLIED PHYSICS LETTERS 104 1 12406  2014年01月 [査読有り][通常論文]
     
    We investigate the electron-spin injection dynamics via tunneling from an In0.1Ga0.9As quantum well (QW) to In0.5Ga0.5As quantum dots (QDs) in coupled QW-QDs nanostructures. These coupled nanostructures demonstrate ultrafast (5 to 20 ps) spin injection into the QDs. The degree of spin polarization up to 45% is obtained in the QDs after the injection, essentially depending on the injection time. The spin injection and conservation are enhanced with thinner barriers due to the stronger electronic coupling between the QW and QDs. (C) 2014 AIP Publishing LLC.
  • KIBA Takayuki, YANG Xiao-jie, YAMAMURA Takafumi, KUNO Yuki, SUBAGYO Agus, SUEOKA Kazuhisa, MURAYAMA Akihiro
    Appl Phys Lett 103 8 082405-082405-5 - 082405 2013年08月19日 [査読有り][通常論文]
  • Ryosuke Takahashi, Kaori Kuribayashi-Shigetomi, Masahiro Tsuchiya, Agus Subagyo, Kazuhisa Sueoka, Takaharu Okajima
    International Symposium on Micro-NanoMechatronics and Human Science, MHS 2013, Nagoya, Japan, November 10-13, 2013 1 - 3 IEEE 2013年 [査読有り][通常論文]
  • Mizuno Taichi, Hosoi Hirotaka, Subagyo Agus, Oishi Suguru, Ikeuchi Akira, Hiura Satoshi, Sueoka Kazuhisa
    Jpn J Appl Phys 51 8 08KB03 - 08KB03-4 The Japan Society of Applied Physics 2012年08月25日 [査読有り][通常論文]
     
    Fe3O4 is one of the important oxide materials and its surface structure should be well understood to enable application of this material. We report the first noncontact atomic force microscopy (NC-AFM) results for Fe3O4(001) thin films. The observed films were grown homoepitaxially on magnetite thin films substrate. A low-energy electron diffraction pattern shows the well-known (\sqrt{2}\times \sqrt{2})R45° reconstructed structure. The observed minimum step height is 0.21 nm, corresponding to the distance between the same planes. We obtain two types of atomic-scale NC-AFM images. One image shows bright protrusions along the [100] and [010] directions at intervals of 0.84 nm corresponding to a unit cell of the (\sqrt{2}\times \sqrt{2})R45° reconstructed structure. The other image shows a more detailed atomic structure with 0.6 and 0.3 nm corrugations.
  • Ikeuchi Akira, Hiura Satoshi, Mizuno Taichi, Kaji Eisaku, Subagyo Agus, Sueoka Kazuhisa
    Jpn J Appl Phys 51 8 08KB02 - 08KB02-5 The Japan Society of Applied Physics 2012年08月25日 [査読有り][通常論文]
     
    We have studied the surface atomic configurations around antiphase domain boundaries (APBs) in epitaxial magnetite (Fe3O4) thin films on MgO(001) by scanning tunneling microscopy (STM). The observed surface of the Fe3O4 films is the B-plane terminating surface with the (\sqrt{2}\times\sqrt{2})R45^{\circ} reconstruction. Several variations of APBs are observed by STM at atomic resolution. The observed APBs are categorized into a APBs labeled by three different phase shift vectors: in-plane 1/4[110], in-plane 1/2[100], and out-of-plane 1/4[101]. We discussed how these APBs appear on the surface. The proportions of the APBs with 1/4[110], 1/2[100], and 1/4[101] shifts are about 38, 1, and 61%, respectively, in our experiment.
  • A. Okada, Y. Mizutani, A. Subagyo, H. Hosoi, M. Nakamura, K. Sueoka, K. Kawahara, T. Okajima
    Appl. Phys. Lett. 99 26 263703-1 - 263703-3 2011年12月26日 [査読有り][通常論文]
     
    We investigated dynamic force propagation between focal adhesions of fibroblast cells cultured on polydimethylsiloxane micropost substrates, by atomic force microscopy. Live cells were mechanically modulated by the atomic force microscopy probe bound to cell apical surfaces at 0.01-0.5 Hz, while microposts served as a force sensor at basal surfaces. We observed that cells exhibited rheological behavior at the apical surface but had no apparent out-of-phase response at the basal surface, indicating that the dynamic force propagating through cytoskeletal filaments behaves in an elastic manner. Moreover, the direction of the propagated force was observed to be intimately associated with the prestress. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3672225]
  • Tsubasa Ichikawa, Yuji Sakamoto, Agus Subagyo, Kazuhisa Sueoka
    APPLIED OPTICS 50 34 H211 - H219 2011年12月 [査読有り][通常論文]
     
    The research on reflectance distributions in computer-generated holograms (CGHs) is particularly sparse, and the textures of materials are not expressed. Thus, we propose a method for calculating reflectance distributions in CGHs that uses the finite-difference time-domain method. In this method, reflected light from an uneven surface made on a computer is analyzed by finite-difference time-domain simulation, and the reflected light distribution is applied to the CGH as an object light. We report the relations between the surface roughness of the objects and the reflectance distributions, and show that the reflectance distributions are given to CGHs by imaging simulation. (C) 2011 Optical Society of America
  • Ichikawa Tsubasa, Sakamoto Yuji, Subagyo Agus, Sueoka Kazuhisa
    PRACTICAL HOLOGRAPHY XXV: MATERIALS AND APPLICATIONS 7957 2011年 [査読有り][通常論文]
  • Ishida N, Subagyo A, Ikeuchi A, Sueoka K
    The Review of scientific instruments 80 9 093703  2009年09月 [査読有り][通常論文]
  • Kaji Eisaku, Subagyo Agus, Arita Masashi, Sueoka Kazuhisa
    JOURNAL OF APPLIED PHYSICS 105 7 2009年04月01日 [査読有り][通常論文]
  • Takeda Seiji, Nakamura Motonori, Subagyo Agus, Ishii Atsushi, Sueoka Kazuhisa, Mukasa Koichi
    SENSORS AND ACTUATORS B-CHEMICAL 132 1 9 - 12 2008年05月28日 [査読有り][通常論文]
  • A. Subagyo, Y. Sasaki, H. Oka, K. Sueoka
    physica status solidi (b) 244 12 4482 - 4485 2007年12月 [査読有り]
  • Takeda S, Nakamura M, Ishii A, Subagyo A, Hosoi H, Sueoka K, Mukasa K
    Nanoscale research letters 2 4 207 - 212 Springer 2007年03月 [査読有り][通常論文]
     
    We fabricated a pH-sensitive device on a glass substrate based on properties of carbon nanotubes. Nanotubes were immobilized specifically on chemically modified areas on a substrate followed by deposition of metallic source and drain electrodes on the area. Some nanotubes connected the source and drain electrodes. A top gate electrode was fabricated on an insulating layer of silane coupling agent on the nanotube. The device showed properties of an n-type field effect transistor when a potential was applied to the nanotube from the top gate electrode. Before fabrication of the insulating layer, the device showed that the p-type field effect transistor and the current through the source and drain electrodes depend on the buffer pH. The current increases with decreasing pH of the CNT solution. This device, which can detect pH, is applicable for use as a biosensor through modification of the CNT surface.
  • Eisaku Kaji, Agus Subagyo, Kazuhisa Sueoka
    Physica Status Solidi (C) Current Topics in Solid State Physics 4 12 4364 - 4367 2007年 [査読有り][通常論文]
     
    The surface crystallographic structure and magnetic structure of magnetite thin films epitaxially grown on a MgO(001) substrate were investigated by means of a scanning tunnelling microscope (STM), magnetic force microscope (MFM) and Spin-polarized scanning electron microscopy (Spin-SEM). The STM investigation and MFM measurement were performed in-situ and in an ambient condition, respectively. After exposing the sample to air, a Spin-SEM image was acquired. Spin-dependent contrasted SEM images could be obtained after cleaning the sample surfaces. The cleaning procedure is annealing the sample at 250°C in an ultra high vacuum (UHV) below 3 × 10-8 Pa for 3 hours. The STM observation indicates the thin films have antiphase domains and the observed MFM images reflect a cease in micromagnetic domain structures. Spin-SEM images indicate that large-scale magnetic inhomogeneity of a few μm is the inhomogeneity of the perpendicular magnetic moments of the films. Due to the spatial resolution limitation of our Spin-SEM system, the correlation between the fine and coarse magnetic structures of the thin films induced by the antiphase domain boundaries is not clear, however, we have suggested the annealing process alone in a UHV makes the spin configuration of the thin films visible using a conventional Spin-SEM system. © 2007 WILEY-VCH Verlag GmbH & Co. KGaA.
  • Kaji Eisaku, Subagyo Agus, Sueoka Kazuhisa
    PHYSICA STATUS SOLIDI C - CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 4, NO 12 4 12 4364 - 4367 2007年 [査読有り][通常論文]
  • Subagyo Agus, Sueoka Kazuhisa
    PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON NANOSCIENCE AND TECHNOLOGY 61 1102 - 1106 2007年 [査読有り][通常論文]
  • Subagyo Agus, Sueoka Kazuhisa
    Jpn J Appl Phys 45 3B 2255 - 2258 Published by the Japan Society of Applied Physics through the Institute of Pure and Applied Physics 2006年03月27日 [査読有り]
     
    Fe3O4(001) film surfaces having a ($\sqrt{2} \times \sqrt{2}$)$R$45° reconstruction are studied by scanning tunneling microscopy (STM) and spin-polarized STM (SP-STM). The reconstruction is induced by ordered arrays of oxygen vacancy at B-terminated surfaces as revealed by STM. Fe cation rows having a wavelike structure oriented along the [110] direction with a separation of 0.6 nm are observed. A single Fe cation with a 0.3 nm periodicity within the cation rows is resolved. Instead of a single Fe cation, SP-STM imaged an alternation of high and low corrugations representing Fe3+–Fe3+ dimers and Fe2+–Fe2+ dimers, respectively. The resolving of Fe dimers having different spin states by SP-STM is due to the contribution of spin-polarized tunneling current. The Fe3+–Fe3+ and Fe2+–Fe2+ dimers have a separation of about 0.6 nm in the [110] direction, while in the [$1\bar{1}0$] direction these dimers alternate by about 0.65 and 0.55 nm. The separation is consistent with the wavelike row structure on the ($\sqrt{2}\times \sqrt{2}$)$R$45° reconstructed Fe3O4(001) film surfaces.
  • Ishida Nobuyuki, Subagyo Agus, Sueoka Kazuhisa
    INTERNATIONAL JOURNAL OF NANOSCIENCE, VOL 5, NO 6 5 6 895 - + 2006年 [査読有り][通常論文]
     
    We performed STM measurements on the K/GaAs(110) surface with high K coverage. The K atoms gradually disappeared while scanning the tip over the surface at negative sample bias voltage. The phenomenon strongly occurred over the scanning area and can be explained by the field-induced surface diffusion from the scanning area to radial direction. Considering the interaction between the dipole moment of the adsorbed K atoms and the electric field, we discuss the relationship between the static and induced dipole moment of K atoms on a GaAs(110) surface.
  • Oka Hirofumi, Subagyo Agus, Sueoka Kazuhisa
    INTERNATIONAL JOURNAL OF NANOSCIENCE, VOL 5, NO 6 5 6 935 - + 2006年 [査読有り][通常論文]
  • Subagyo Agus, Sueoka Kazuhisa
    Japanese journal of applied physics. Pt. 1, Regular papers & short notes 44 7B 5447 - 5450 Published by the Japan Society of Applied Physics through the Institute of Pure and Applied Physics 2005年07月26日 [査読有り]
     
    We report the role of atom defects on the charge freezing of Fe3O4(001) surfaces studied by spin-polarized scanning tunneling microscopy (SP-STM) using a Ni tip. Epitaxially grown Fe3O4(001) films on a MgO(001) substrate were used as samples. Atomically flat surfaces are obtained by annealing in an ultrahigh vacuum and in oxygen. The surfaces exhibit a $(\sqrt{2}\times\sqrt{2})R45$° reconstruction as revealed by STM with a W tip. STM images indicate surface termination at B-sites. An atomic structure with a 0.3 nm periodicity is observed within the cation rows that are aligned along the [110] direction. SP-STM images show a pronouncedly different periodicity of 1.2 nm on areas having surface defects such as cation vacancies. This corrugation with a 1.2 nm periodicity can be attributed to a charge localization of Fe3+ and Fe2+ ions that are trapped by cation vacancies and then isolated from the electron hopping process. The results also indicate the important role of oxygen vacancies in modifying the 1.2 nm periodicity.
  • HIROSE Ryusuke, ARITA Masashi, HAMADA Kouichi, TAKAHASHI Yasuo, SUBAGYO Agus
    Jpn J Appl Phys Part 2 44 24-27 L790-L792 - L792 Japan Society of Applied Physics 2005年07月10日 [査読有り][通常論文]
     
    A technique for measuring the conductance of a small number of particles during transmission electron microcopy (TEM) observation is demonstrated. By using a custom-designed TEM holder, an Au tip was brought into contact with Fe nanodots contained in a SrF2 film deposited on another Au tip. The conductance shows Coulomb-blockade-like characteristics even at room temperature.
  • Agus Subagyo, Kazuhisa Sueoka, Koichi Mukasa
    Journal of Magnetism and Magnetic Materials 290-291 1037 - 1039 2005年04月 [査読有り]
  • K Sueoka, A Subagyo, H Hosoi, K Mukasa
    NANOTECHNOLOGY 15 10 S691 - S698 2004年10月 [査読有り][通常論文]
     
    We review our research on the application of scanning tunnelling microscopy (STM) and non-contact atomic force microscopy (NC-AFM) for magnetic imaging in high spatial resolution even down to the atomic scale. In the first part, we propose a new experimental scheme of spin-polarized STM (SP-STM) with a GaAs spin probe to obtain a large contribution of spin-polarized electrons in the tunnelling current. This is yielded by injecting the spin-polarized photo-excited electrons in an optically pumped GaAs tip into the spin-polarized empty states near the Fermi level of a bcc-Fe(001) surface. According to the bandgap energy of GaAs and the surface state of the sample observed at 0.4 eV above the Fermi level, the spin-dependant electron injection can be achieved by applying a sample bias voltage of -1 V. The tunnel current in the positive bias region depends on the helicity of the circular polarized pumping light, and is modified when the applied magnetic field is reversed. Mapping the current asymmetry provides a spin-dependent SP-STM image. In the second part, we describe the progress towards spin imaging with NC-AFM. The spin imaging can be achieved by detecting short-range magnetic interaction such as exchange interaction between a ferromagnetic tip and a magnetic sample. We demonstrate the capabilities of NC-AFM by imaging the spin structure of an antiferromagnetic NiO(001) surface on the atomic scale. The cross-sectional line profiles of the atomically resolved images obtained using several ferromagnetic tips (Fe, Ni) were analysed by adding the atomic corrugation amplitude on the basis of the periodicity of the image. The results of the analysis show that the difference of the neighbouring maxima depends on the crystal direction. On the other hand, no significant indication of the directional dependency can be seen on the images obtained by using a non-magnetic Si tip. The directional dependency coincides with the antiferromagnetic spin alignment of the NiO(001) surface.
  • Ishida Nobuyuki, Subagyo Agus, Hosoi Hirotaka, Sueoka Kazuhisa, Mukasa Koichi
    Japanese journal of applied physics. Pt. 1, Regular papers & short notes 43 7 4557 - 4560 Published by the Japan Society of Applied Physics through the Institute of Pure and Applied Physics 2004年07月15日 [査読有り][通常論文]
     
    We investigated the adsorption structures of K atoms on a GaAs(110) surface as a function of coverage by scanning tunneling microscopy. We found three kinds of adsorption structures, namely, the low-density linear chain, the asymmetric chain and the symmetric chain. At the initial stage with low coverage, K atoms form low-density linear and asymmetric chains. With increasing coverage, low-density linear chains disappeared and the number of asymmetric chains increased. At high adsorption coverage, K atoms began to form symmetric chains, so that the symmetric and asymmetric chains coexisted. The strong dependency of the adsorption structure on the coverage is discussed by considering a recent theoretical work.
  • Oka Hirofumi, Subagyo Agus, Sawamura Makoto, Sueoka Kazuhisa, Mukasa Koichi
    Japanese journal of applied physics. Pt. 1, Regular papers & short notes 41 Part 1, No. 7B 4969 - 4972 社団法人応用物理学会 2002年07月30日 [査読有り]
     
    Scanning tunneling microscopy (STM) measurements reveal that Fe thin films epitaxially grown on a MgO(001) substrate under appropriate conditions have an atomic step-terrace surface with a $c(2\times 2)$ surface reconstruction, and that this surface is often accompanied by line-like patterns along the Fe$\langle 110 \rangle$ direction. We have investigated the electronic properties of the patterns in detail by atomically resolved STM. We found that the pattern is a domain phase boundary of the $c(2\times 2)$ domains, and that the domain boundaries consist of atoms exhibiting a ($1\times 1$) structure. The STM image shows remarkable bias-voltage dependency as indicated by the contrast inversion between the patterns and $c(2\times 2)$ domains as the polarity of the applied bias-voltage is changed, and the contrast achieved its maximum value at $+0.2$ V. This bias-voltage dependency of the patterns can be explained by the existence of surface states which are observed at around 0.2 eV above the Fermi level on the Fe(001) ($1\times 1$) surface and 0.4 eV on the $c(2\times 2)$ domains.
  • SAWAMURA Makoto, HOSOI Hirotaka, KIMURA Michiya, EILERS Guido, SUBAGYO Agus, SUEOKA Kazuhisa, MUKASA Koichi
    Transactions of the Magnetics Society of Japan 2 2 63 - 68 公益社団法人日本磁気学会 2002年05月01日 
    The geometries and spin electronic states of single atomic strands consisting of Fe atoms were studied in comparison with similar strands of Au, Pt, Cu, Na, Mg, Al, Si, and Xe atoms, using first principles molecular orbital methods. Finite cluster models comprising six atoms were constructed. The optimized geometry of the wire was obtained for each element as the wire was elongated. Abnormally long atomic distances were observed in the cases of Fe, Au, Pt, Cu, Na, Mg, and Xe wires, which have shallow and broad s-orbitals in their valence shells. On the other hand, the wires formed from Al and of Siatoms collapsed while growing to lengths in excess of the bulk atomic distances. These atoms have σ-bonds with their neighboring atoms in the wires. Their electronic states create steep and deep potential energy wells, which prohibit long atomic distances.
  • H Ohno, K Yoh, T Doi, A Subagyo, K Sueoka, K Mukasa
    JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B 19 6 2280 - 2283 2001年11月 [査読有り][通常論文]
     
    We report on the growth of planar/patterned Fe thin films on InAs(100) substrates and their subsequent characterization using reflection high-energy electron diffraction, low-energy electron diffraction, superconducting quantum interference device, and four-terminal contact resistance measurements. Epitaxial growth of body-centered-cubic Fe crystal on InAs(100) was verified for growth temperatures of 23 degreesC and 175 degreesC. A patterned Fe wire array showed clear uniaxial shape anisotropy with the easy axis along the wire direction. Its coercive force was found to depend on the growth temperature and the width of the Fe wires. Four-terminal contact resistance measurement of Fe/n-InAs revealed that Fe forms decent ohmic contact to the InAs substrate with a resistivity of the order of 10(-6) Omegacm(2). Samples crown at room temperature showed equally decent or even better magnetic and electrical characteristics than those obtained by higher temperature growth. These results indicate that the Fe/InAs hybrid structures have definite potential for spin-related semiconductor devices with practical process sequences. (C) 2001 American Vacuum Society.
  • Oka Hirofumi, Subagyo Agus, Sawamura Makoto, Sueoka Kazuhisa, Mukasa Kōichi
    Japanese journal of applied physics. Pt. 1, Regular papers & short notes 40 6 4334 - 4336 Publication Office, Japanese Journal of Applied Physics, Faculty of Science, University of Tokyo 2001年06月30日 
    Fe thin films with flat surfaces are obtained on a MgO(001) substrate at a growth temperature of 550 K. The surfaces with atomically flat and wide terraces exhibit a $c(2{\times}2)$ reconstructed structure. To evaluate the effect of impurity atoms at the surface on the surface structures, scanning tunneling spectroscopy (STS), reflection high energy electron diffraction (RHEED) and X-ray photoelectron spectroscopy (XPS) studies were performed. The differential conductivity (${dI/dV}$) spectrum of the $c(2{\times}2)$ Fe(001) thin-film surfaces indicates an intense peak at the sample bias voltage of 0.4 V. Since there is no clear evidence of impurity adatoms forming such a surface structure, we expect that the topmost atoms are Fe, and that the observed peak originates from surface states.
  • Subagyo Agus, Oka Hirofumi, Eilers Guido, Sueoka Kazuhisa, Mukasa Koichi
    Japanese journal of applied physics. Pt. 1, Regular papers & short notes 39 Part 1, No. 6B 3777 - 3779 社団法人応用物理学会 2000年06月30日 [査読有り]
     
    We report the first atomic-resolution scanning tunneling microscopy (STM) image of epitaxial bcc-Fe(001) films grown on MgO(001) substrates. A 50-Å-thick Fe film grown at a growth temperature of 550 K formed square pyramidal islands with atomically flat terraces. The terraces were found to range between 5 nm and 20 nm in width separated by monoatomic high steps. The film exhibited a ($1\times 1$) unreconstructed structure at a film thickness below 19 Å; however, a reconstructed surface was found on thicker films. The atomic-resolution STM image and low energy electron diffraction (LEED) observation indicated that the reconstructed structure is a c($2\times 2$) structure.
  • A Subagyo, K Sueoka, K Mukasa
    NUCLEATION AND GROWTH PROCESSES IN MATERIALS 580 429 - 434 2000年 [査読有り][通常論文]
     
    We reported a scanning tunneling microscopy(STM) observation on the growth mode transition from 2D-nucleation to spiral growth in the epitaxial Fe films on MgO(001). As the growth temperature is increased to above 493 K, a temperature region where the Schwoebel barrier is overcome, the Fe films grow in a 2D-nucleation and growth mode formed atomically flat films. The 2D-nucleation transformed into a spiral growth as increasing film thickness. At a growth temperature of 493 K, the transition of 2D nucleation to the spiral growth was observed at a film thickness of 75 Angstrom. The critical thickness of the emergence of growth transition decreased as the growth temperature is increased.
  • A. Subagyo, K. Sueoka, K. Mukasa
    IEEE Transactions on Magnetics 35 5 3037 - 3039 1999年09月 [査読有り]
  • Subagyo Agus, Sueoka Kazuhisa, Mukasa Koichi, Hayakawa Kazunobu
    Japanese Journal of Applied Physics 38 Part 1, No. 6B 3820 - 3825 公益社団法人 応用物理学会 1999年06月30日 [査読有り]
     
    Substrate preparation procedure dependence of the growth morphology and magnetic properties of 25 ML bcc-Fe(001) thin films epitaxially grown on MgO(001) substrates in a wide range of growth temperature was investigated by means of scanning tunneling microscopy (STM) and superconducting quantum interference device (SQUID). The growth morphology of Fe thin films was uniform both on a polished and on an annealed substrate, but nonuniform on a cleaved substrate. It was very difficult to obtain a flat Fe thin film on the cleaved substrate, and the film became discontinuous at or above a growth temperature of 493 K. At a growth temperature of 550 K, atomically defined terraces of Fe thin films were formed on the annealed substrate but were not formed on the polished substrate. A continuous film grown on the annealed substrate at a temperature of 593 K has a less magnetic anisotropy. The other continuous films have low coercivity of about 8 Oe and a biaxial magnetic anisotropy. The dependency of the growth morphology and magnetic properties of Fe thin films upon substrate preparation procedures concerning the presence of step-terraces on the substrate surface is discussed.
  • 末岡 和久, 細山 直樹, SUBAGYO Agus, 武笠 幸一, 早川 和延
    表面科学 19 8 522 - 526 日本表面科学会 1998年08月10日 [査読有り][通常論文]
  • Agus SUBAGYO, Yukinari HAYASHI, Susumu TOKUDA, Masaki YOSHINO, Junji NANJO
    Denki Kagaku oyobi Kogyo Butsuri Kagaku 66 2 206 - 211 1998年02月05日 [査読有り]

MISC

講演・口頭発表等

  • Mapping cell-to-cell variations in power-law rheology investigated by multifrequency force modulation atomic force microscopy  [通常講演]
    M. Sawano, R. Tanaka, R. Takahashi, K. Kurubayashi-Shigetomi, A. Subagyo, K. Sueoka, T. Okajima
    MOLECULAR BIOLOGY OF THE CELL 2016年 AMER SOC CELL BIOLOGY
  • Ryosuke Takahashi, Kaori Kuribayashi-Shigetomi, Agus Subagyo, Kazuhisa Sueoka, Takaharu Okajima
    2014 INTERNATIONAL SYMPOSIUM ON MICRO-NANOMECHATRONICS AND HUMAN SCIENCE (MHS) 2014年 IEEE
     
    Rheological properties of cells are associated with various cell functions and thus are considered to be an indicator for diagnosing cell disease. Atomic force microscopy (AFM) is a powerful tool for quantifying the mechanical properties of isolated single cells. For example, our AFM technique reported previously revealed that the complex shear modulus of single cells exhibited a large cell-to-cell variation which depended on frequency. By contrast, rheological properties of cell population such as cells in confluent condition have been less understood. Thus, it is valuable to investigate how quantitatively the AFM technique can be applied to cell population such as cells in confluent condition. As a result, rheological properties of cells in confluent conditions can be relatively rapidly measured by our AFM setup modifying a force modulation AFM mode. This suggests that the AFM technique is useful for diagnosing not only single cells but also cell population and cell assembly.
  • Ryosuke Tanaka, Yuki Fujii, Junpei Kikkawa, Kaori Kuribayashi-Shigetomi, Agus Subagyo, Kazuhisa Sueoka, Takaharu Okajima
    2014 INTERNATIONAL SYMPOSIUM ON MICRO-NANOMECHATRONICS AND HUMAN SCIENCE (MHS) 2014年 IEEE
     
    Cells rapidly undergo cell division during the embryogenesis. Such dynamic behaviors of cells during the embryogenesis are considered to be strongly associated with their mechanical properties such as cell-cell mechanical interactions and cell stiffness. However, the interplay between the morphogenesis and the mechanical property of whole cell assembly during the developmental process has not been well understood. To exploring the mechanism of forming the whole cell assembly, we proposed atomic force microscopy (AFM) combined with a microarray technique, which allows us to map mechanical property of the whole cell assembly. In this AFM setup, the cell assembly is randomly directed in the microarray well, and thus the average mechanical property of the whole cell assembly can be reconstructed from mapping images obtained from different cell assemblies.
  • PingGen Cai, Ryosuke Takahashi, Kaori Kuribayashi-Shigetomi, Agus Subagyo, Kazuhisa Sueoka, Takaharu Okajima
    2014 INTERNATIONAL SYMPOSIUM ON MICRO-NANOMECHATRONICS AND HUMAN SCIENCE (MHS) 2014年 IEEE
     
    To sort living cells according to our needs, it is important to understand how degree cell property measured for cell sorting fluctuates in time. Mechanical property of cells is one of essential indicators for cell sorting. Thus, in this study, we attempted to measure a time evolution of viscoelastic property such as complex shear modulus, G* of single cells adhered on substrates using atomic force microscopy (AFM). We observed that the G* largely fluctuated in time even the cells are placed on substrates in a confined condition. This indicates that in mechanical cell sorting, mechanical fluctuations of cells should be carefully estimated so that cells are precisely separated by taking the measured data involving cell fluctuations into account.

所属学協会

  • ナノ学会   応用物理学会   フラーレン・ナノチューブ・グラフェン学会   

共同研究・競争的資金等の研究課題

  • 日本学術振興会:科学研究費助成事業
    研究期間 : 2021年04月 -2024年03月 
    代表者 : アグス スバギョ
     
    初年度では,炭素吸着したマグネタイト表面のスピン偏極度向上の効果を調べるために,申請の段階で実施し始めた通電加熱法の炭素吸着の条件の最適化を図った.また,通電加熱法の炭素吸着の結果を踏まえ,電子ビーム加熱蒸着装置を用いた炭素吸着を検討して実施した.STMやLEED等による原子構造の評価,XPSを用いたマグネタイト組成や炭素吸着時の不純物の評価もおこなった. マグネタイト試料は,MgO(001)基板にマグネタイト(001)薄膜をエピタキシャル成長させて作成した.マグネタイト薄膜表面は,清浄表面である再構成構造を示すことと,逆位相境界を有することを原子分解STMで確認した.このようなマグネタイト清浄表面上に,通電加熱したグラッシーカーボンフォイルを用いて炭素吸着をおこなった結果,マグネタイト薄膜表面の鉄原子列上に原子レベルの炭素吸着の他に,クラスター状に吸着した炭素もわずかに観察されていた.炭素吸着のない鉄原子上と原子状炭素吸着の局所電子状態を比較すると,吸着炭素上の局所電子状態では新たな状態がみられ,理論計算によって導かれた電子状態におけるスピン偏極したダウンスピンの電子状態と一致した. 均一な炭素吸着した表面を作製するために,炭素吸着チェンバーに通電加熱法の他に電子ビーム加熱蒸着装置を設置した.さらに,炭素吸着のレートを正確に把握するために膜厚モニターも設置した.電子ビーム加熱蒸着装置を用いることにより,通電加熱法より低いレートでの吸着が可能であり,クラスター状の炭素吸着が少なく,より均一な炭素原子吸着したマグネタイト薄膜表面が作製できた.

産業財産権

  • WO/2010/079573:電界効果トランジスタ、その製造方法およびバイオセンサ  2010年
    アグス スバギョ, 中村基訓, 山林智明, 高橋理, 菊地洋明, 近藤勝則
  • WO/2009/144902:電界効果トランジスタおよびその製造方法  2009年
    菊地洋明, 高橋理, 近藤勝則, 山林智明, 小笠原邦男, 石垣忠, 稗貫豊, 中村基訓, アグス スバギョ


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