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Yamashita, Keishiro*; Komatsu, Kazuki*; Klotz, S.*; Fabelo, O.*; Fernndez-D
az, M. T.*; Abe, Jun*; Machida, Shinichi*; Hattori, Takanori; Irifune, Tetsuo*; Shimmei, Toru*; et al.
Proceedings of the National Academy of Sciences of the United States of America, 119(40), p.e2208717119_1 - e2208717119_6, 2022/10
Times Cited Count:7 Percentile:35.59(Multidisciplinary Sciences)Here we present the first elucidation of the disordered structure of ice VII, the dominant high-pressure form of water, at 2.2 GPa and 298 K from both single-crystal and powder neutron diffraction techniques. We reveal the three-dimensional atomic distributions from the maximum entropy method and unexpectedly find a ring-like distribution of hydrogen in contrast to the commonly-accepted discrete sites. In addition, total scattering analysis at 274 K clarified the difference in the intermolecular structure from ice VIII, the ordered counterpart of ice VII, despite an identical molecular geometry. Our complementary structure analyses robustly demonstrate the unique disordered structure of ice VII. Furthermore, these noble findings are related to the proton dynamics which drastically vary with pressure, and will contribute to an understanding of the structural origin of anomalous physical properties of ice VII under pressures.
Yamashita, Keishiro*; Komatsu, Kazuki*; Ohara, Takashi; Munakata, Koji*; Irifune, Tetsuo*; Shimmei, Toru*; Sugiyama, Kazumasa*; Kawamata, Toru*; Kagi, Hiroyuki*
High Pressure Research, 42(1), p.121 - 135, 2022/03
Times Cited Count:4 Percentile:45.73(Physics, Multidisciplinary)Sasao, Eiji; Danhara, Toru*; Yamashita, Toru*; Hayashi, Joji*
Mizunamishi Kaseki Hakubutsukan Kenkyu Hokoku, (48), p.9 - 19, 2021/05
Petrographic description of tuffs in the Miocene Mizunami Group has been made to offer basic data. This report includes the descriptions of 14 and 4 tuff beds in the Mizunami and Iwamura Groups, respectively. Followings are presented in this report; mineral and heavy mineral composition, shape of volcanic glass, and refractive indices of volcanic glass and plagioclase.
Ikuta, Masafumi*; Niwa, Masakazu; Danhara, Toru*; Yamashita, Toru*; Maruyama, Seiji*; Kamataki, Takanobu*; Kobayashi, Tetsuo*; Kurosawa, Hideki*; Kokubu, Yoko; Hirata, Takafumi*
Chishitsugaku Zasshi, 122(3), p.89 - 107, 2016/03
We carried out mineral composition analysis, morphological classification of volcanic glass shards and refractive index measurements of the glass shards and orthopyroxene from the eruption products from Sakurajima volcano. In this study, refractive indexes of hydrated and non-hydrated parts within each individual glass shard were measured separately. This measurements in consideration of hydration in glass shards made possible distinct discrimination of the pumice samples from the three eruption events of Bunmei, An-ei, and Taisho. Pumice layers in the core samples obtained from the southern part of the Miyazaki Plain were also identified as the Sakurajima-Bunmei tephra by the above mentioned analyses, and also by the data of radiocarbon dating for coaly materials included in the pumice layers. Occurrences of the pumice layers suggest that the Sakurajima-Bunmei tephra could have reached the southern part of Miyazaki Plain as pumice falls.
Kato, Takashi; Tsuji, Hiroshi; Ando, Toshinari; Takahashi, Yoshikazu; Nakajima, Hideo; Sugimoto, Makoto; Isono, Takaaki; Koizumi, Norikiyo; Kawano, Katsumi; Oshikiri, Masayuki*; et al.
Fusion Engineering and Design, 56-57, p.59 - 70, 2001/10
Times Cited Count:18 Percentile:75.65(Nuclear Science & Technology)no abstracts in English
Tsuji, Hiroshi; Okuno, Kiyoshi*; Thome, R.*; Salpietro, E.*; Egorov, S. A.*; Martovetsky, N.*; Ricci, M.*; Zanino, R.*; Zahn, G.*; Martinez, A.*; et al.
Nuclear Fusion, 41(5), p.645 - 651, 2001/05
Times Cited Count:58 Percentile:82.82(Physics, Fluids & Plasmas)no abstracts in English
Danhara, Toru*; Yamashita, Toru*
JNC TJ7420 2005-075, 108 Pages, 1997/03
no abstracts in English