Updated on 2024/12/07

写真a

 
TANIGUCHI, Takuya
 
Affiliation
Affiliated organization, Center for Data Science
Job title
Associate Professor(non-tenure-track)
Degree
Doctor of Engineering ( 2019.03 Waseda University )
Mail Address
メールアドレス

Research Experience

  • 2021.04
    -
    Now

    Waseda University   Center for Data Science   Associate Professor (without tenure)

  • 2019.04
    -
    2021.03

    Waseda University   Center for Data Science   Assistant Professor (without tenure)

  • 2017.04
    -
    2019.03

    Japan Society for the Promotion of Science

Education Background

  • 2014.04
    -
    2019.03

    Waseda University   Graduate School of Advanced Science and Engineering   Department of Advanced Science and Engineering  

  • 2009.04
    -
    2014.03

    Waseda University   School of Advanced Science and Engineering   Department of Life Science and Medical Bioscience  

Committee Memberships

  • 2020.08
    -
    2020.11

    Molecular Chirality Asia 2020  事務局長

Professional Memberships

  • 2022.10
    -
    Now

    人工知能学会

  • 2020.07
    -
    Now

    日本結晶学会

  • 2014.06
    -
    Now

    日本化学会有機結晶部会

  • 2014.05
    -
    Now

    光化学協会

  • 2012.10
    -
    Now

    日本化学会

  • 2020.06
    -
    2022.12

    日本機械学会

▼display all

Research Areas

  • Structural organic chemistry and physical organic chemistry / Organic functional materials

Research Interests

  • organic functional materials

  • materials informatics

  • materials science

Awards

  • 井上研究奨励賞

    2019.12   井上科学振興財団  

  • Ono Azusa Memorial Award

    2019.03   Waseda University  

  • 学生講演賞

    2019.03   日本化学会第99春季年会  

  • Poster Presentation Award

    2017.07   Chirality 2017  

  • poster prize

    2017.04   ICCOSS XXIII  

  • 優秀講演賞

    2016.09   第25回有機結晶シンポジウム  

  • Outstanding Poster Presentation Award

    2015.07   ICCOSS XXII  

  • ポスター賞

    2015.06   Symposium on Molecular Chirality 2015  

▼display all

Media Coverage

 

Papers

  • Proton Conduction in Chiral Molecular Assemblies of Azolium–Camphorsulfonate Salts

    Chisato Sato, Shun Dekura, Hiroyasu Sato, Kohei Sambe, Takashi Takeda, Takuya Kurihara, Motohiro Mizuno, Takuya Taniguchi, Jiabing Wu, Takayoshi Nakamura, Tomoyuki Akutagawa

    Journal of the American Chemical Society    2024.07  [Refereed]

    DOI

  • Knowledge distillation of neural network potential for molecular crystals

    Takuya Taniguchi

    Faraday Discussions    2024.07  [Refereed]

    Authorship:Lead author, Last author, Corresponding author

    DOI

  • Effectiveness and limitation of the performance prediction of perovskite solar cells by process informatics

    Ryo Fukasawa, Toru Asahi, Takuya Taniguchi

    Energy Advances    2024.03  [Refereed]

    Authorship:Last author, Corresponding author

     View Summary

    Perovskite solar cells have garnered significant interest owing to their low fabrication costs and comparatively high power conversion efficiency (PCE). The performance of these cells is influenced not solely by...

    DOI

  • Exploration of elastic moduli of molecular crystals via database screening by pretrained neural network potential

    Takuya Taniguchi

    CrystEngComm    2024.01  [Refereed]

    Authorship:Lead author, Last author, Corresponding author

     View Summary

    Elastic moduli of molecular crystals can be predicted using pretrained neural network potential, showing sufficient agreement with experimental data.

    DOI

  • Superelastic Behaviors of Molecular Crystals

    Takuya Taniguchi

    Shape Memory Alloys - New Advances    2023.10  [Refereed]  [Invited]

    Authorship:Lead author, Last author, Corresponding author

    DOI

  • Graph Comparison of Molecular Crystals in Band Gap Prediction Using Neural Networks

    Takuya Taniguchi, Mayuko Hosokawa, Toru Asahi

    ACS Omega    2023.10  [Refereed]

    Authorship:Lead author, Corresponding author

    DOI

  • Unraveling the Structural and Property Differences between Highly Similar Chiral and Racemic Crystals Composed of Analogous Molecules

    Kazuki Ishizaki, Daisuke Takagi, Toru Asahi, Masahiro Kuramochi, Takuya Taniguchi

    Crystal Growth & Design    2023.06  [Refereed]

    Authorship:Last author, Corresponding author

    DOI

  • Molecular screening for solid–solid phase transition by machine learning

    Daisuke Takagi, Kazuki Ishizaki, Toru Asahi, Takuya Taniguchi

    Digital Discovery    2023.06  [Refereed]

    Authorship:Last author, Corresponding author

     View Summary

    Solid–solid phase transition of molecular crystals is generally found by chance empirically. In this study, we constructed a machine learning framework to screen molecules that will exhibit solid–solid phase transitions...

    DOI

  • Superelasticity of a photo-actuating chiral salicylideneamine crystal

    Takuya Taniguchi, Kazuki Ishizaki, Daisuke Takagi, Kazuki Nishimura, Hiroki Shigemune, Masahiro Kuramochi, Yuji C. Sasaki, Hideko Koshima, Toru Asahi

    Communications Chemistry   5 ( 1 )  2022.01  [Refereed]

    Authorship:Lead author, Corresponding author

     View Summary

    <title>Abstract</title>Superelasticity is a type of elastic response to an applied external force, caused by a phase transformation. Actuation of materials is also an elastic response to external stimuli such as light and heat. Although both superelasticity and actuation are deformations resulting from stimulus-induced stress, there is a phenomenological difference between the two with respect to whether force is an input or an output. Here, we report that a molecular crystal manifests superelasticity during photo-actuation under light irradiation. The crystal exhibits stepwise twisted actuation due to two effects, photoisomerization and photo-triggered phase transition, and the actuation behavior is simulated based on a dynamic multi-layer model. The simulation, in turn, reveals how the photoisomerization and phase transition progress in the crystal, indicating superelasticity induced by modest stress due to the formation of photoproducts. This work provides not only a successful simulation of stepwise twisted actuation, but also to the best of our knowledge the first indication of superelasticity induced by light.

    DOI

  • Reformation of Thalidomide from its Hydrolysis Compound via Intramolecular Dehydration

    Takuya Taniguchi, Miri Nakamura, Koichi Tsutao, Kohei Otogawa, Yoshiyuki Ogino, Toru Asahi

    Chemistry Letters    2021.04  [Refereed]

    Authorship:Lead author

    DOI

  • Actuation performance of a photo-bending crystal modeled by machine learning-based regression

    Kazuki Ishizaki, Ryota Sugimoto, Yuki Hagiwara, Hideko Koshima, Takuya Taniguchi, Toru Asahi

    CrystEngComm    2021  [Refereed]  [Invited]

    Authorship:Corresponding author

     View Summary

    <p>The bending deflection and blocking force of photo-bending crystals of different sizes were experimentally measured at various light intensities, and then modeled by the machine learning-based regression.</p>

    DOI

  • Crystal actuator based on a thermal phase transition and photothermal effect

    Yuki Hagiwara, Takuya Taniguchi, Toru Asahi, Hideko Koshima

    JOURNAL OF MATERIALS CHEMISTRY C   8 ( 14 ) 4876 - 4884  2020.04  [Refereed]

     View Summary

    Mechanically responsive materials have been increasingly explored, mainly in terms of photoisomerization. Here, we report the bending actuation of salicylideneaniline crystals induced by a thermal phase transition and photothermal effect. Long rod-like crystals bent reversibly on repeated heating and cooling near the transition temperature. The bend motion was also induced by the photothermal effect under ultraviolet (UV) and visible light irradiation, with and without phase transition. The photothermal-based temperature rise at the irradiated site of the crystal edge resulted in localised elongation near the crystal surface and slight bending due to the temperature gradient in the thickness direction. This bending motion was amplified by tip displacement at the opposite end of the long rod-like crystal. Finally, high-frequency bending actuation of 25 Hz was achieved by pulsed UV irradiation. Thus, the results of this study demonstrate the potential and versatility for mechanical crystal development based on the photothermal effect.

    DOI

  • Statistical Modeling of Photo-Bending Actuation of Hybrid Silicones Mixed with Azobenzene Powder

    Takuya Taniguchi, Loic Blanc, Toru Asahi, Hideko Koshima, Pierre Lambert

    ACTUATORS   8 ( 4 )  2019.12  [Refereed]

    Authorship:Lead author, Corresponding author

     View Summary

    Mechanically responsive materials are promising as next-generation actuators for soft robotics, but have scarce reports on the statistical modeling of the actuation behavior. This research reports on the development and modeling of the photomechanical bending behavior of hybrid silicones mixed with azobenzene powder. The photo-responsive hybrid silicone bends away from the light source upon light irradiation when a thin paper is attached on the hybrid silicone. The time courses of bending behaviors were fitted well with exponential models with a time variable, affording fitting constants at each experimental condition. These fitted parameters were further modeled using the analysis of variance (ANOVA). Cubic models were proposed for both the photo-bending and unbending processes, which were parameterized by the powder ratio and the light intensity. This modeling process allows such photo-responsive materials to be controlled as actuators, and will possibly be effective for engineering mechanically responsive materials.

    DOI

  • Mechanically Responsive Crystals by Light and Heat

    Hideko Koshima, Takuya Taniguchi, Toru Asahi

    Mechanically Responsive Materials for Soft Robotics     57 - 82  2019.11  [Refereed]

    DOI

  • Photomechanical Azobenzene Crystals

    Takuya Taniguchi, Toru Asahi, Hideko Koshima

    CRYSTALS   9 ( 9 )  2019.09  [Refereed]

    Authorship:Lead author

     View Summary

    Photomechanically responsive materials are promising candidates for future smart actuator applications. The photo-responsive behaviors originate from the photoisomerization of photochromic molecules. A typical photochromic compound, azobenzene, has been studied extensively in the solution state and has played a crucial role in the photomechanical behaviors of materials such as polymers and gels, via chemical bridging with their matrix. In contrast to polymers and gels, the photomechanical attributes of molecular crystals have not progressed to the same degree, due to their rigidity and fragility. However, the past decade has witnessed an increasing number of reports of the photomechanical motion of molecular crystals, including azobenzene crystals. This paper reviews the current state-of-the-art of mechanically responsive azobenzene crystals, including the history, crystal design strategy, and future promising applications.

    DOI

  • Photo-triggered phase transition of a crystal

    Takuya Taniguchi, Hiroyasu Sato, Yuki Hagiwara, Toru Asahi, Hideko Koshima

    COMMUNICATIONS CHEMISTRY   2  2019.02  [Refereed]

    Authorship:Lead author

     View Summary

    Structural phase transitions induced by external stimuli such as temperature, pressure, electromagnetic fields, and light play crucial roles in controlling the functions of solid-state materials. Here we report a new phase transition, referred to as the photo-triggered phase transition, of a photochromic chiral salicylideneamine crystal. The crystal, which exhibits a thermal single-crystal-to-single-crystal phase transition which is reversible upon heating and cooling, transforms to the identical phase upon light irradiation at temperatures lower than the thermal transition temperature. The photo-triggered phase transition originates from the strain of trans-keto molecules produced by enol-keto photoisomerization owing to the small energy barrier associated with changes in the crystal structure. The photo-triggered phase is metastable and returns to the initial stable phase via back isomerization from the trans-keto to enol form.

    DOI

  • Photomechanical and thermomechanical molecular crystals

    Takuya Taniguchi, Hideko Koshima

    ACTA CRYSTALLOGRAPHICA A-FOUNDATION AND ADVANCES   74   E123 - E123  2018.08  [Refereed]

    DOI

  • Walking and rolling of crystals induced thermally by phase transition

    Takuya Taniguchi, Haruki Sugiyama, Hidehiro Uekusa, Motoo Shiro, Toru Asahi, Hideko Koshima

    NATURE COMMUNICATIONS   9  2018.02  [Refereed]

    Authorship:Lead author

     View Summary

    The mechanical motion of materials has been increasingly explored in terms of bending and expansion/contraction. However, the locomotion of materials has been limited. Here, we report walking and rolling locomotion of chiral azobenzene crystals, induced thermally by a reversible single-crystal-to-single-crystal phase transition. Long plate-like crystals with thickness gradient in the longitudinal direction walk slowly, like an inchworm, by repeated bending and straightening under heating and cooling cycles near the transition temperature. Furthermore, thinner, longer plate-like crystals with width gradient roll much faster by tilted bending and then flipping under only one process of heating or cooling. The length of the crystal is shortened above the transition temperature, which induces bending due to the temperature gradient to the thickness direction. The bending motion is necessarily converted to the walking and rolling locomotion due to the unsymmetrical shape of the crystal. This finding of the crystal locomotion can lead to a field of crystal robotics.

    DOI

  • Two-step photomechanical motion of a dibenzobarrelene crystal

    Takuya Taniguchi, Ayumi Kubota, Tatsuya Moritoki, Toru Asahi, Hideko Koshima

    RSC ADVANCES   8 ( 60 ) 34314 - 34320  2018  [Refereed]

    Authorship:Lead author

     View Summary

    Photomechanical crystals are interesting from both basic and applied perspectives, and thus it is important to develop new examples. We investigated the photomechanical bending behaviour of a photochromic crystal of a dibenzobarrelene derivative. When a plate-like crystal was irradiated with ultraviolet (UV) light at 365 nm, two-step bending was observed. In the first step, the crystal quickly bent away from the light source, with an accompanying crystal colour change from colourless to purple. In the second step, under prolonged UV light, the bending returned slowly and then the crystal bent up towards the opposite direction, accompanied by an additional colour change to light yellow. Spectroscopic measurements and X-ray crystallographic analysis suggested that a long-lived biradical species is generated immediately upon UV light irradiation via a Norrish type II intramolecular hydrogen abstraction, and then the final photoproducts are formed under continuous UV exposure. X-ray crystallographic analysis before and after UV light irradiation for a few seconds revealed that the longitudinal axis (a axis) of the crystal elongated slightly after irradiation, which is consistent with the direction of the first-step bending. Based on these results, we propose that first-step bending could be induced by a biradical species, generated via a Norrish type II intramolecular hydrogen abstraction, and the second-step bending could originate from the formation of a mixture of final photoproducts under prolonged light irradiation.

    DOI

  • Mechanical Motion of Chiral Azobenzene Crystals with Twisting upon Photoirradiation

    Takuya Taniguchi, Juri Fujisawa, Motoo Shiro, Hideko Koshima, Toru Asahi

    CHEMISTRY-A EUROPEAN JOURNAL   22 ( 23 ) 7950 - 7958  2016.06  [Refereed]

    Authorship:Lead author

     View Summary

    The photomechanical motion of chiral crystals of trans-azobenzene derivatives with an (S)- and (R)-phenylethylamide group was investigated and compared with a racemic crystal. Changes in the UV/Vis absorption spectra of the powdered crystals before and after UV irradiation were measured by using an optical waveguide spectrometer, showing that the lifetime of the cis-to-trans thermal backisomerization of the chiral crystals was faster than that of the racemic crystals. Upon UV irradiation, a long plate-like chiral microcrystal bent away from the light source with a twisting motion. A square-like chiral microcrystal curled toward the light with some twisting. Reversible bending of a rod-like chiral microcrystal was repeatable over twenty-five cycles. In contrast, bending of a plate-like racemic microcrystal was small. A possible mechanism for the bending and twisting motion was discussed based on the optimized cis conformer determined by using calculations, showing that the bending motion with twisting is caused by elongation along the b axis and shrinkage along the a axis.

    DOI

  • Mechanical motion of molecular crystals induced by [4+4] photodimerisation

    Hideko Koshima, Hidetaka Uchimoto, Takuya Taniguchi, Jun Nakamura, Tsuyoshi Asahi, Toru Asahi

    CRYSTENGCOMM   18 ( 38 ) 7305 - 7310  2016  [Refereed]

     View Summary

    The photomechanical bending of crystals of a stilbene-type compound substituted with anthracene and indanone groups, (E)-2-(9-anthrylmethylene)-1-indanone (trans-1), was investigated. When a narrow plate-like microcrystal was irradiated with ultraviolet (UV) light at 365 nm, the crystal gradually bent away from the light source and finally reached a semicircular shape after more than 10 min. A larger rod-like crystal, approximately 10 mm in length, also exhibited a slight bending motion. The cessation of UV irradiation caused the bent crystals to return very slowly to their straight form. In the crystals, the anthracene planes of two neighbouring trans-1 molecules are arranged in a head-to-tail parallel manner, with a short plane-to-plane distance of only 3.72 angstrom. The H-1 nuclear magnetic resonance spectra of trans-1 crystals before and after UV irradiation revealed the intermolecular [4 + 4] photodimerisation of the two anthracene planes, while the trans-to-cis photoisomerisation was not significant. The UV-vis absorption spectra of the trans-1 powder crystals, obtained using a diffuse reflectance spectrophotometer, showed a gradual increase in absorbance between 200 and 500 nm with increasing UV irradiation time, reaching a maximum after 1 h. Thermal back-monomerisation was very slow in the dark, not recovering the initial spectrum even after 25 days. The fluorescence spectra at 570 nm, derived from the anthracene excimer, decreased in intensity with increasing UV irradiation time due to a decrease in the amount of anthracene chromophore via photodimerisation. In situ X-ray measurements revealed that the bending of the crystals was caused by slight elongation of the b axis of the unit cell, corresponding to the long axis of the rod-like crystals. Calculations revealed that the observed crystal elongation could be explained by an optimised head-to-tail [4 + 4] orientation of the anthracene dimer.

    DOI

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Books and Other Publications

  • 未来技術2023-2032 全産業編

    ( Part: Contributor, 第8章17, 18)

    日経BP社  2023.02 ISBN: 9784296200948

Presentations

  • 分子結晶開発における機械学習の活用

    谷口卓也  [Invited]

    日本化学会 第104春季年会 (2024) 

    Presentation date: 2024.03

  • Data-driven control of photo-bending behavior of hybrid silicones mixed with azobenzene powder

    Takuya Taniguchi  [Invited]

    Carbon Materials and Nanotechnology (CMAN-2021) 

    Presentation date: 2021.01

  • Photomechanical and thermomechanical molecular crystals

    Takuya Taniguchi, Hideko Koshima  [Invited]

    31st European Crystallographic Meeting 

    Presentation date: 2018

    Event date:
    2018.08
     
     

Research Projects

  • 効率的な結晶構造予測による有機多孔質材料の構造探索

    住友財団  環境研究助成(一般研究)

    Project Year :

    2024.11
    -
    2026.11
     

  • 機械学習によるHOF材料の安定性シミュレーション

    日本学術振興会  科研費

    Project Year :

    2024.04
    -
    2026.03
     

  • 機械学習を活用した有機固相転移の計画的創出

    科学技術振興機構(JST)  ACT-X

    Project Year :

    2023.10
    -
    2026.03
     

  • AI分子シミュレータの評価および固体材料開発を志向した活用検討(3)

    ENEOS株式会社  共同研究

    Project Year :

    2024.04
    -
    2025.03
     

  • 有機固体MIのWebプラットフォーム開発

    科学技術振興機構(JST)  大学発新産業創出プログラム(START)

    Project Year :

    2023.07
    -
    2024.03
     

  • AI分子シミュレータの評価および固体材料開発を志向した活用検討(2)

    ENEOS株式会社 

    Project Year :

    2023.03
    -
    2024.03
     

  • Infrastructure development of materials informatics for organic solid materials

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Early-Career Scientists

    Project Year :

    2022.04
    -
    2024.03
     

  • 太陽紫外光を力学エネルギーに変換する有機結晶材料の創製

    八洲環境技術振興財団 

    Project Year :

    2022.04
    -
    2023.03
     

    谷口卓也

  • AI分子シミュレータの評価および固体材料開発を志向した活用検討

    ENEOS株式会社 

    Project Year :

    2022.03
    -
    2023.03
     

  • 革新的な固体材料の創出に向けたMI基盤技術の開発

    早稲田大学―ENEOS シーズ探索研究助成

    Project Year :

    2021.07
    -
    2022.03
     

    谷口卓也

  • Development of mechanically responsive soft crystals by photo-triggered phase transition

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)

    Project Year :

    2020.04
    -
    2022.03
     

  • Quantitative analysis and function development of molecular crystals with photo-triggered phase transition

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Research Activity start-up

    Project Year :

    2019.08
    -
    2021.03
     

    Taniguchi Takuya

     View Summary

    The photo-triggered phase transition is a phenomenon in which a structural phase transition of a crystal is induced by light, and differs from other light-responsive phenomena in that the structural change propagates to regions where light does not reach. We measured the elastic moduli of photoisomerized crystals that exhibit this light-triggered phase transition and found that there is a large anisotropy in the elastic moduli. We succeeded in performing a quantitative analysis of the deformation as well as a finite element method simulation analysis of the torsional deformation behavior of the crystal with photo-triggered phase transition. We also succeeded in measuring the force generated by light irradiation, and found that the photo-triggered phase transition leads to a unique time course of force generation behavior.

  • 光と熱によって自由に動き回るメカニカル結晶の開発

    日本学術振興会  科学研究費助成事業 特別研究員奨励費

    Project Year :

    2017.04
    -
    2019.03
     

    谷口 卓也

     View Summary

    当該年度までに、光トリガー相転移という興味深い現象を見出していたため、当該年度はその光トリガー相転移について詳細に調べ、発現機構を明らかにした。光トリガー相転移は、熱的な構造相転移が起きる光反応性結晶において発見された現象である。この結晶は2度の構造相転移が起こり、温度変化に応じてα、β、γ相の間を変化できる。
    これまでに-50℃で結晶に光照射すると光トリガー相転移が起きることは見出していた。これはβ相の結晶に光を当てるとγ相の結晶構造に変化することを意味する。新たに、α相およびγ相の結晶に光照射したところ、光トリガー相転移は起こらず、結晶相は変化しなかった。したがって、光トリガー相転移はβ相において特有の現象であることがわかった。
    このβ相からγ相への光トリガー相転移の発現機構を考察するため、光異性化による生成物trans-keto体の分子構造を量子化学計算により最適化した。その結果、元のenol体とは二面角が大きく異なり、光異性化による構造変化が大きいことがわかった。この分子構造変化が結晶中で起きると、trans-keto体は周りの分子にひずみを与えると考えられる。実際の結晶において、光照射前は全ての分子がEnol体である。光照射すると、照射面から光異性化が進行し、trans-keto体ができ、ひずみを与え始める。ある程度trans-keto体が生成すると、そのひずみを解消するように結晶全体の構造がドミノ倒しのように進む。これが、光トリガー相転移の発現機構である。この時、β相からγ相へのエネルギー障壁が0.2 kJ/molと小さいことも光トリガー相転移の発現に寄与していると考えられる。
    光照射によって、光異性化と光トリガー相転移を起こすことができ、それらを組み合わせた複雑なメカニカル機能を創出することができた。

  • 光駆動型医療用カテーテルの開発

    早稲田大学理工学術院総合研究所  若手研究者支援事業アーリーバード

    Project Year :

    2016.06
    -
    2017.03
     

    谷口卓也

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Misc

  • 分子結晶の物性予測における分子・結晶グラフの比較

    谷口卓也, 細川真由子, 朝日透

    2023年度人工知能学会全国大会(第37回)    2023.06

    Authorship:Lead author, Corresponding author

    Research paper, summary (national, other academic conference)  

    DOI

  • Application of Materials Informatics for Organic Crystals

    Takuya TANIGUCHI

    Nihon Kessho Gakkaishi   65 ( 2 ) 139 - 144  2023.05  [Refereed]  [Invited]

    Authorship:Lead author, Corresponding author

    Article, review, commentary, editorial, etc. (scientific journal)  

    DOI

  • Mechanically Responsive Soft Crystals Induced by Light and Heat

    Takuya TANIGUCHI

    Nihon Kessho Gakkaishi   63 ( 1 ) 31 - 37  2021.02  [Refereed]  [Invited]

    Authorship:Lead author, Corresponding author

    Article, review, commentary, editorial, etc. (scientific journal)  

    DOI

  • 世界初!歩き回るロボット結晶が誕生-まったく新しいソフトロボット実現への可能性

    小島秀子, 谷口卓也, 朝日透

    化学    2018.09  [Invited]

    Article, review, commentary, editorial, etc. (trade magazine, newspaper, online media)  

  • 加熱・冷却すると歩いたり転がったりする「ロボット結晶」を開発! – ソフトロボットへの応用に期待

    谷口卓也

    academist Journal    2018.03

    Article, review, commentary, editorial, etc. (trade magazine, newspaper, online media)  

  • 光を当てるとねじれ曲がる結晶 − 分子の反応を材料の動きへ

    谷口卓也

    academist Journal    2017.09

    Article, review, commentary, editorial, etc. (trade magazine, newspaper, online media)  

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Syllabus

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Sub-affiliation

  • Affiliated organization   Global Education Center

Research Institute

  • 2022
    -
    2024

    Waseda Center for a Carbon Neutral Society   Concurrent Researcher

Internal Special Research Projects

  • 有機固体材料におけるグラフ表現の検討と材料開発

    2023  

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    分子結晶は創薬や材料科学などの多岐にわたる分野で研究されている。開発過程においてはトライアンドエラーが避けられず、多大なリソースが消費される。効率的な分子結晶デザインを実現するためには、実験前の分子スクリーニングが有効である。そこで本研究では、有機固体材料のグラフ表現の確立を目指した。分子結晶のグラフ表現を、バンドギャップ予測という物性予測の課題において比較した。中間的なCrystGraphの表現が、分子グラフや他の異なる複雑さを持つ結晶グラフと比較して、最も優れた回帰指標を提供した。バンドギャップは結晶の物性であり、その予測において中間的なCrystGraphがMolGraphよりも誤差を約0.4倍減少させ、適度な相関係数を示したことは注目に値する。手作業で収集したデータを用いた汎化テストでは、中間的なCrystGraphを使用した場合がMolGraphや既報研究で開発されたアンサンブルモデルよりも優れた性能を検証した。CSDからダウンロードした大規模なデータセットでのバンドギャップスクリーニングでは、合理的な推論結果を得て、最も低いおよび最も高いバンドギャップを持つ潜在的な結晶を同定した。本研究の新規性は、グラフの表現比較を通じて結晶グラフが分子グラフに対して持つ相対的な効果を明確にした点にある。このワークフローは他の物性にも応用が可能であり、機能性分子結晶の効率的なスクリーニングと設計に寄与する可能性を示している。

  • 分子結晶の機械学習ポテンシャル開発

    2023  

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    分子結晶は創薬や材料科学などの多岐にわたる分野で研究されている。開発過程ではトライアンドエラーが必須であり、多大なリソースを要する。分子結晶の効率的なデザインを実現するためには、実験前の分子スクリーニングが有効である。そこで本研究では、分子結晶向けの機械学習ポテンシャル開発を目指した。本年度はまず、既存の機械学習ポテンシャルであるPreFfered Potential(PFP)の精度を評価した。分子結晶の弾性特性は、医薬品および材料応用において重要だが、弾性定数テンソルの理論計算は計算コストが高い。PFPを用いた分子結晶の弾性率予測の可能性を評価したところ、実験値との十分な一致を示し、ハートリー・フォック計算を上回る性能が確認された。また、ナノインデンテーション測定による特定方向でのヤング率を精密に予測できること、およびヤング率の大きさと結晶構造の関係が明らかになった。分子結晶の弾性率データベーススクリーニングによって、大きな弾性率を有する結晶と小さな弾性率を有する結晶の両方が提案された。続いて、Materials Projectで学習した機械学習ポテンシャルであるCHGNetに有機結晶データを追加学習させた際の効率を調査した。Materials Projectは無機結晶を中心とした計算データベースであるため、追加学習を施さない場合、有機結晶のポテンシャル計算には大きな誤差が生じる。少量の有機結晶データを追加学習することで予測精度が向上することが確認された。追加学習では、学習率1e-3では精度が改善しなかったが、学習率を1e-2に調整することで予測精度が改善された。これは、無機結晶に特化したニューラルネットワークのハイパーパラメータを、より汎用的なハイパーパラメータに遷移させるため、勾配の谷を超える必要があるためと考えられる。

  • 分子結晶に対するグラフ生成モデルの有用性検討

    2022  

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    分子結晶は創薬や材料科学などの多岐にわたる分野で研究されているが、その開発にあたってはトライアンドエラーの繰り返しが必要であり、多大なリソースがかかっている。本研究では、グラフ構造を使って分子結晶を生成することを目指して、分子結晶におけるグラフ表現の有用性を比較した。分子結晶を分子グラフおよび結晶グラフで数理データ化し、グラフニューラルネットワーク(GNN)に入力した。目的変数はバンドギャップを対象とした。GNNでの回帰分析の結果から、分子グラフよりも結晶グラフの方が良い回帰性能を与えることが分かり、分子結晶における結晶グラフの有用性が確認できた。またこの結果から、分子間相互作用のバンドギャップに与える寄与を考察した。

  • グラフ構造を用いた分子結晶の構造ー機能の相関探索

    2021  

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    分子結晶は創薬や材料科学などの多岐にわたる分野で研究されているが、その開発にあたってはトライアンドエラーの繰り返しが必要であり、多大なリソースがかかっている。本研究では、グラフ構造を使って分子結晶をデータ化し、機械学習によって構造と種々の機能との関係性を探索した。分子結晶を分子グラフおよび結晶グラフで数理データ化し、グラフニューラルネットワーク(GNN)に入力した。目的変数はバンドギャップおよび融点を対象とした。GNNでの回帰分析の結果から、既存のフィンガープリント法で分子を表現するよりもグラフ構造で分子や結晶を表現する方が分子結晶のマテリアルズインフォマティクスに適していることが分かった。

  • 統計的機械学習に基づく有機結晶の構造相転移予測と設計

    2020  

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    構造相転移は結晶構造が変化する現象であり、種々の機能を創発・制御することができため工学的に重要であるにも関わらず、構造相転移の発現を理論計算によって予測することは困難であった。そこで本研究では、構造相転移を発現する有機結晶を予測・設計することを目的とし、構造相転移に関係する記述子を検討した。 分子間相互作用エネルギー(以下E_i)および格子エネルギー(以下E_l)を計算した結果、構造相転移を発現する結晶は相転移温度を境にして不連続に変化したE_iが存在した。一方、構造相転移を発現しない結晶ではE_iおよびE_lは線形に変化した。これらの結果により、E_iやE_lの温度依存性の挙動から相転移の有無を区別できることが分かった。

  • メカニカル結晶と高分子のハイブリッド化によるアクチュエータ材料創製

    2020  

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    本研究は、メカニカル有機結晶の長所と高分子の長所を合わせもった、光屈曲性ハイブリッド材料を創製することを目的とし、メカニカル結晶の出力最適化手法の開発およびハイブリッド化の高分子検討を行った。 メカニカル結晶の光屈曲を結晶サイズ・光照射強度を変えて観察し、撮影した動画から先端変位の時間変化を得た。時系列データから得た特徴量に対して回帰分析を行うことで、屈曲挙動を表す数理モデルを構築することができた。 このメカニカル結晶を高分子PVDF-HFPに様々な比率で混合した。高い混合比では均一なハイブリッド膜を得ることができず、比較的低い混合比の方がハイブリッド膜作製において最適であることが分かった。

  • 機械学習による構造相転移する有機結晶の開拓

    2019  

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    The structural phase transition of molecular crystals is a mechanism to exhibit and/or regulate materials’ properties such as electromagnetic effects and actuation response. While the development of crystals with phase transition is of substantial importance, it has been still difficult to predict the occurrence which molecular crystals afford the rare phenomenon. To solve this problem, I tried to find efficient descriptors to account for a structural phase transition. In the first step, I compared available crystallographic software as to usability and interpretability. I tested COMPACK implemented in Mercury, XPac, CrystalCMP, CrystalExplore. Based on the comparison of some crystal data, XPac was useful to compare a small number of isostructural crystals, and CrystalCMP was useful for dendrogram visualization when the amount of data is much more. CrystalExplore can visualize intermolecular interaction as Hirshfeld surface and plot.&nbsp; It has an advantage in the interpretability of structural factors for a phase transition. Currently, some polymorphic crystals data are analyzed by the visualization and the obtained descriptors with these software.

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