TAMURA Tomoyuki

写真a

Affiliation Department etc.

Department of Physical Science and Engineering
Department of Physical Science and Engineering

Title

Assistant Professor

Mail Address

E-mail address

Graduate School

  •  
    -
    2004.03

    The University of Tokyo  Graduate School, Division of Engineering  Doctor's Course  Completed

External Career

  • 2011.01
    -
    2011.03

      Researcher  

  • 2005.01
    -
    2010.12

      Researcher  

  • 2004.04
    -
    2004.12

      Researcher  

 

Papers

  • Fast and scalable prediction of local energy at grain boundaries: Machine-learning based modeling of first-principles calculations

    T. Tamura, M. Karasuyama, R. Kobayashi, R. Arakawa, Y. Shiihara, I. Takeuchi

    Modelling and Simulation in Materials Science and Engineering ( IOP Publishing Ltd )  25   075003-1 - 075003-21   2017.08  [Refereed]

    Research paper (scientific journal)   Multiple Authorship

    We propose a new scheme based on machine learning for the ef!cient
    screening in grain-boundary (GB) engineering. A set of results obtained from
    !rst-principles calculations based on density functional theory (DFT) for a
    small number of GB systems is used as a training data set. In our scheme, by
    partitioning the total energy into atomic energies using a local-energy analysis
    scheme, we can increase the training data set signi!cantly. We use atomic
    radial distribution functions and additional structural features as atom
    descriptors to predict atomic energies and GB energies simultaneously using
    the least absolute shrinkage and selection operator, which is a recent standard
    regression technique in statistical machine learning. In the test study with fcc-
    Al [110] symmetric tilt GBs, we could achieve enough predictive accuracy to
    understand energy changes at and near GBs at a glance, even if we collected training data from only 10 GB systems. The present scheme can emulate timeconsuming
    DFT calculations for large GB systems with negligible computational
    costs, and thus enable the fast screening of possible alternative GB
    systems.

  • Knowledge-Transfer based Cost-effective Search for Interface Structures: A Case Study on fcc-Al [110] Tilt Grain Boundary

    Tomohiro Yonezu, Tomoyuki Tamura, Ichiro Takeuchi, Masayuki Karasuyama

    arXiv     2017.08

    Research paper (scientific journal)   Multiple Authorship

  • Combination of first-principles molecular dynamics and XANES simulations for LiCoO2-electrolyte interfacial reactions in a Li-ion battery

    Tomoyuki Tamura, Masanori Kohyama, Shuji Ogata

    Physical Review B ( American Physical Society )  96   035107-1 - 035107-8   2017.07  [Refereed]

    Research paper (scientific journal)   Multiple Authorship

    We performed a first-principles molecular dynamics (FPMD) simulation of the interfacial reactions between
    a LiCoO2 electrode and a liquid ethylene carbonate (EC) electrolyte. For configurations during the FPMD
    simulation, we also performed first-principles Co K-edge x-ray absorption near-edge structure (XANES)
    simulations,which can properly reproduce the bulk and surface spectra of LiCoO2.We observed strong absorption
    of an EC molecule on the LiCoO2 {110} surface, involving ring opening of the molecule, bond formation between oxygen atoms in the molecule and surface Co ions, and emission of one surface Li ion, while all the surface Co ions remain Co3+. The surface Co ions having the bond with an oxygen atom in the molecule showed remarkable changes in simulated K-edge spectra which are similar to those of the in situ observation under electrolyte soaking [D. Takamatsu et al., Angew. Chem., Int. Ed. 51, 11597 (2012)]. Thus, the local environmental changes of surface Co ions due to the reactions with an EC molecule can explain the experimental spectrum changes.

  • Experimental and theoretical investigation of the structural role of titanium oxide in CaO-P2O5-TiO2 invert glass

    H. Maeda, T. Tamura, T. Kasuga

    J. Physical Chemistry B ( American Chemical Society )  121   5433 - 5438   2017.05  [Refereed]

    Research paper (scientific journal)   Multiple Authorship

    Understanding the structural role of TiO2 in
    calcium phosphate invert glasses is key for developing a new
    glass design for biomedical applications. Experimental and
    computational analysis methods were used to investigate the
    impact of TiO2 substitution in these glasses. Spectroscopic
    analyses indicated that titanium oxide exists as both TiO4 and
    TiO6 units, leading to the formation of Ti−O−P bonds, in
    spite of depolymerization of the phosphate chains. Classical
    molecular dynamics showed that the presence of TiO2
    influences the phosphate units and CaO polyhedral structures. The formation of the Ti−O−P bonds caused an increase in
    the network connectivity of the invert glasses, leading to the improvement of the glass forming ability and wettability. The
    addition of TiO2 to calcium phosphate invert glasses led to the introduction of bioactivity.

  • Improving the biocompatibility of tobermorite by incorporating calcium phosphate clusters

    H. Maeda, T. Tamura, T. Kasuga

    Bio-Medical Materials and Engineering   28   31 - 36   2017.03  [Refereed]

    Research paper (scientific journal)   Multiple Authorship

    BACKGROUND: In our earlier work, tobermorite containing calcium phosphate (CP) clusters (CP-Tob) was hydrothermally
    prepared in the CaO–SiO2–P2O5–H2O system for biomedical applications.
    OBJECTIVE: CP-Tob was used to investigate the influence of CP cluster incorporation on its biocompatibility.
    METHODS: Tobermorite samples with and without CP clusters were hydrothermally prepared at 180°C for 40 h. The biocompatibility,
    structure, and density of states of the tobermorite samples were investigated by experimental and first principles
    methods.
    RESULTS: The amounts of lysozyme and bovine serum albumin adsorbed on CP-Tob were higher than those on tobermorite
    without CP clusters. Cluster incorporation caused a decrease in the solubility, resulting in the enhancement of the cell compatibility.
    The calculated results indicated that incorporating clusters, which interact with the silicate units of tobermorite, led to a
    change of the density of states of tobermorite.
    CONCLUSIONS: Incorporation of CP clusters in tobermorite led to improvement of the biocompatibility evaluated by biological
    and computational analyses.

  • Development of Neural-Network Interatomic Potentials for Structural Materials

    R. Kobayashi, T. Tamura, I. Takeuchi, S. Ogata

    Solid State Phenomena   258   69 - 72   2016.12  [Refereed]

    Research paper (scientific journal)   Multiple Authorship

  • Enhanced Si–O Bond Breaking in Silica Glass by Water Dimer: A Hybrid Quantum–Classical Simulation Study

    T. Kouno, S. Ogata, T. Shimada, T. Tamura, R. Kobayashi

    J. Phys. Soc. Jpn.   65   054601-1 - 054601-9   2016.04  [Refereed]

    Research paper (scientific journal)   Multiple Authorship

  • "Atomic and electronic structures of Li4Ti5O12/Li7Ti5O12 (001) interfaces by first-principles calculations

    S. Tanaka, M. Kitta, T. Tamura, Y. Maeda, T. Akita, M. Kohyama

    J. Material Science   49   4032 - 4037   2014.02  [Refereed]

    Research paper (scientific journal)   Multiple Authorship

  • "First-principles investigation of possible clustering of noble gas atoms implanted in bcc tungsten

    T. Tamura, R. Kobayashi, S. Ogata, A. M. Ito

    Modelling Simulation Material Science Engineering   22   015002-1 - 015002-12   2013.11  [Refereed]

    Research paper (scientific journal)   Multiple Authorship

Presentations

  • First-principles K-edge XANES simulation for doped Ti in CaO-P2O5 invert glass

    T. Tamura, H. Maeda, M. Kohyama

    GOMD2017 (Glass & Optical Materials Division Annual Meeting)  (Hawaii)  2017.06  -  2017.06  American Ceramics Society

  • Formation and Structure of Calcium Phosphate Invert Glasses

    T. Kasuga, H. Maeda, T. Tamura, A. Obata, S. Lee, T. Nakano  [Invited]

    GOMD2017 (Glass & Optical Materials Division Annual Meeting)  (Hawaii)  2017.06  -  2017.06  American Ceramics Society

  • Statistical Prediction of Grain-Boundary Properties

    T. Tamura, R. Arakawa, M. Karasuyama, R. Kobayashi, S. Ogata

    PRICM9 (The 9th Pacific Rim International Conference of Advanced Materials and Processing)  2016.08  -  2016.08 

  • Statistical Prediction of Grain-boundary Properties

    T. Tamura, R. Arakawa, M. Karasuyama, R. Kobayashi, S. Ogata

    ISAM4 2016 (The third International Symposium on Atomistic Modeling for Mechanics and Multiphysics of Materials)  (Brno , Czech Republic)  2016.06  -  2016.06 

  • First-principles in-situ XAS simulation of chemical reaction at cathode-electrolyte interface in Li-ion batteries

    T. Tamura  [Invited]

    Pacifichem 2015 (The International Chemical Congress of Pacific Basin Societies 2015)  (Honolulu, Hawaii)  2015.12  -  2015.12 

  • First-principles in-situ XAS simulation of chemical reaction at cathode - electrolyte interface in Li-ion batteries

    T. Tamura, R. Kobayashi, S. Ogata

    ISEPD2015 (The 16th International Symposium on Eco-materials Processing and Design)  (Kathmandu, Nepal)  2015.01  -  2015.01 

  • First-principles study of transition-metal K-edge XANES for Li-rich solid-solution layered cathode material

    T. Tamura, R. Kobayashi, S. Ogata

    ACCMS-VO9 (The 9th General Meeting of Asian Consortium on Computational Materials Science - Virtual Organization)  (沖縄科学技術大学院大学)  2014.12  -  2014.12