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Fleurence, A.*; Lee, C.-C.*; Friedlein, R.*; Fukaya, Yuki; Yoshimoto, Shinya*; Mukai, Kozo*; Yamane, Hiroyuki*; Kosugi, Nobuhiro*; Yoshinobu, Jun*; Ozaki, Taisuke*; et al.
Physical Review B, 102(20), p.201102_1 - 201102_6, 2020/11
Times Cited Count:2 Percentile:12.54(Materials Science, Multidisciplinary)no abstracts in English
Sato, Yusuke*; Fukaya, Yuki; Cameau, M.*; Kundu, A. K.*; Shiga, Daisuke*; Yukawa, Ryu*; Horiba, Koji*; Chen, C.-H.*; Huang, A.*; Jeng, H.-T.*; et al.
Physical Review Materials (Internet), 4(6), p.064005_1 - 064005_6, 2020/06
Times Cited Count:6 Percentile:30.33(Materials Science, Multidisciplinary)no abstracts in English
Wakeda, Masato*; Tsuru, Tomohito; Koyama, Masanori*; Ozaki, Taisuke*; Sawada, Hideaki*; Itakura, Mitsuhiro; Ogata, Shigenobu*
Acta Materialia, 131, p.445 - 456, 2017/06
Times Cited Count:32 Percentile:80.94(Materials Science, Multidisciplinary)Most of the solute species show a significant interaction with the dislocation core, while only several solute species among them, such as Si, P, and Cu, significantly lower the Peierls potential of the screw dislocation motion. A first-principles interaction energy with the "Easy-core" structure excellently correlates with the change in the -surface caused by solute atoms (i.e., chemical misfit). We show the availability of the interaction energy to predict the effect of each species on macroscopic critical resolved shear stress (CRSS) of the dilute Fe alloy. The CRSS at low and high temperature for various alloys basically agree with experiment CRSS. These results provide a novel understanding of the interaction between a screw dislocation and solute species from the first-principles.
Huang, S.-F.*; Terakura, Kiyoyuki*; Ozaki, Taisuke*; Ikeda, Takashi; Boero, M.*; Oshima, Masaharu*; Ozaki, Junichi*; Miyata, Seizo*
Physical Review B, 80(23), p.235410_1 - 235410_12, 2009/12
Times Cited Count:168 Percentile:97.3(Materials Science, Multidisciplinary)Recent studies suggest that the carbon-alloy catalyst with doped nitrogen may be a powerful candidate for cathode catalyst of fuel cell. In this paper, we aim to clarify the microscopic mechanisms of the enhancement in the catalyst activity caused by nitrogen doping using a simple graphene cluster model. We analyze modifications in the electronic structures and the energetical stability for some different configurations of N doping. We extend the analysis to the case of co-doping of nitrogen and boron and propose two possible scenarios explaining the further enhancement of catalytic activity by N and B co-doping.
Fukaya, Yuki; Lee, C.-C.*; Fleurence, A.*; Hasegawa, Yukio*; Ozaki, Taisuke*; Yamada-Takamura, Yukiko*
no journal, ,
no abstracts in English
Kawai, Hiroyuki*; Sekikawa, Takuya; Ozaki, Taisuke*; Furuya, Shinnosuke*; Ono, Yoshiaki*
no journal, ,
First-principles electronic structure calculation software OpenMX is a calculation code based on density functional theory, and is mainly used to obtain the most stable structures and electronic states of materials. In this study, we attempted to develop a method to accelerate OpenMX calculations using a GPU (Graphics Processing Unit), which is usually used for image processing, and succeeded in reducing the calculation time to about one-half of that using the same number of CPUs in a benchmark calculation on DNA. The benchmark calculation on DNA succeeded in reducing the calculation time by about one-half compared to the same number of CPUs. We then applied the method developed in this study to modified-DNA (DNA in which some of the atoms constituting a base pair are replaced with transition metals or organic molecules), which has been investigated using OpenMX, and verified the degree of speed-up. Details of the obtained modified-DNA, including its electronic state, will be presented on the day.