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Su, Y. H.; Shinohara, Takenao; Parker, J. D.*; Oikawa, Kenichi; Kai, Tetsuya; Gong, W.; Ito, Tatsuya; Harjo, S.; Aizawa, Kazuya; Kiyanagi, Yoshiaki*; et al.
Materials Science & Engineering A, 951, p.149607_1 - 149607_16, 2026/01
Times Cited Count：0 Percentile：0.00(Nanoscience & Nanotechnology)
Ti
)
NiSe
Tsuchida, Shun*; Hirose, Yusuke; Sekikawa, Takuya; Ono, Yoshiaki*; Hirahara, Takuya*; Sano, Sumika*; Kawaguchi, Shogo*; Kobayashi, Shintaro*; Uwatoko, Yoshiya*; Settai, Rikio*
Journal of the Physical Society of Japan, 94(11), p.114703_1 - 114703_7, 2025/10
Times Cited Count：0 Percentile：0.00(Physics, Multidisciplinary)We investigated the carrier doping effect on an excitonic insulator TaNiSe by means of the electrical resistivity 
and Hall coefficient 
using single crystals of (TaTi)NiSe, and band calculation. The excitonic transition temperature 
is continuously suppressed to 83 K at 
= 0.104 while preserving the crystal structure. With increasing substitution concentration , a semiconducting increment of and is strongly suppressed and a metallic behavior is observed at > 0.06. Ti substitution can realize an excitonic correlated metallic state. This metallization is explained by the hole doping effect based on the band calculations. Applying pressure to the carrier doped (TaTi)NiSe, we found superconductivity above 2.6 GPa, which is much smaller than that of TaNiSe around 8 GPa. The carrier doping induced by Ti substitution favors superconductivity in this compound.
Oikawa, Kenichi; Matsumoto, Yoshihiro*; Watanabe, Kenichi*; Sato, Hirotaka*; Parker, J. D.*; Shinohara, Takenao; Kiyanagi, Yoshiaki*
Scientific Reports (Internet), 14, p.27990_1 - 27990_11, 2024/11
Times Cited Count：1 Percentile：22.25(Multidisciplinary Sciences)Matsumoto, Yoshihiro*; Oikawa, Kenichi; Watanabe, Kenichi*; Sato, Hirotaka*; Parker, J. D.*; Shinohara, Takenao; Kiyanagi, Yoshiaki*
Journal of Archaeological Science; Reports, 58, p.104729_1 - 104729_10, 2024/10
Oikawa, Kenichi; Sato, Hirotaka*; Watanabe, Kenichi*; Su, Y. H.; Shinohara, Takenao; Kai, Tetsuya; Kiyanagi, Yoshiaki*; Hasemi, Hiroyuki
Journal of Physics; Conference Series, 2605, p.012013_1 - 012013_6, 2023/10
Oikawa, Kenichi; Harjo, S.; Pham, A. H.*; Kawasaki, Takuro; Morito, Shigekazu*; Kiyanagi, Yoshiaki*; Shinohara, Takenao; Kai, Tetsuya; Oba, Takuya*; Ito, Masakazu*
JPS Conference Proceedings (Internet), 33, p.011062_1 - 011062_6, 2021/03
Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.
Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03
Times Cited Count：64 Percentile：95.16(Astronomy & Astrophysics)Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 
C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.
Mo/
Tc generator by (n,
) method, 2Fujita, Yoshitaka; Seki, Misaki; Namekawa, Yoji*; Nishikata, Kaori; Kato, Yoshiaki; Sayato, Natsuki; Tsuchiya, Kunihiko; Sano, Tadafumi*; Fujihara, Yasuyuki*; Hori, Junichi*; et al.
KURNS Progress Report 2019, P. 157, 2020/08
no abstracts in English
Parker, J. D.*; Harada, Masahide; Hayashida, Hirotoshi*; Hiroi, Kosuke; Kai, Tetsuya; Matsumoto, Yoshihiro*; Nakatani, Takeshi; Oikawa, Kenichi; Segawa, Mariko; Shinohara, Takenao; et al.
Materials Research Proceedings, Vol.15, p.102 - 107, 2020/05
Shinohara, Takenao; Kai, Tetsuya; Oikawa, Kenichi; Nakatani, Takeshi; Segawa, Mariko; Hiroi, Kosuke; Su, Y. H.; Oi, Motoki; Harada, Masahide; Iikura, Hiroshi; et al.
Review of Scientific Instruments, 91(4), p.043302_1 - 043302_20, 2020/04
Times Cited Count：88 Percentile：97.30(Instruments & Instrumentation)
He
excimer cluster tracers in superfluid helium-4 via neutron-
He absorption reactionSonnenschein, V.*; Tsuji, Yoshiyuki*; Kokuryu, Shoma*; Kubo, Wataru*; Suzuki, So*; Tomita, Hideki*; Kiyanagi, Yoshiaki*; Iguchi, Tetsuo*; Matsushita, Taku*; Wada, Nobuo*; et al.
Review of Scientific Instruments, 91(3), p.033318_1 - 033318_12, 2020/03
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)Oikawa, Kenichi; Kiyanagi, Yoshiaki*; Sato, Hirotaka*; Omae, Kazuma*; Pham, A.*; Watanabe, Kenichi*; Matsumoto, Yoshihiro*; Shinohara, Takenao; Kai, Tetsuya; Harjo, S.; et al.
Materials Research Proceedings, Vol.15, p.207 - 213, 2020/02
He
clusters via neutron-He absorption reaction toward visualization of full velocity field in quantum turbulenceMatsushita, Taku*; Sonnenschein, V.*; Guo, W.*; Hayashida, Hirotoshi*; Hiroi, Kosuke; Hirota, Katsuya*; Iguchi, Tetsuo*; Ito, Daisuke*; Kitaguchi, Masaaki*; Kiyanagi, Yoshiaki*; et al.
Journal of Low Temperature Physics, 196(1-2), p.275 - 282, 2019/07
Times Cited Count：1 Percentile：3.47(Physics, Applied)Hiroi, Kosuke; Shinohara, Takenao; Hayashida, Hirotoshi*; Parker, J. D.*; Su, Y. H.; Oikawa, Kenichi; Kai, Tetsuya; Kiyanagi, Yoshiaki*
Physica B; Condensed Matter, 551, p.146 - 151, 2018/12
Times Cited Count：10 Percentile：38.06(Physics, Condensed Matter)Kai, Tetsuya; Sato, Setsuo*; Hiroi, Kosuke; Su, Y. H.; Segawa, Mariko; Parker, J. D.*; Matsumoto, Yoshihiro*; Hayashida, Hirotoshi*; Shinohara, Takenao; Oikawa, Kenichi; et al.
Physica B; Condensed Matter, 551, p.496 - 500, 2018/12
Times Cited Count：5 Percentile：20.73(Physics, Condensed Matter)Segawa, Mariko; Oikawa, Kenichi; Kai, Tetsuya; Shinohara, Takenao; Hayashida, Hirotoshi*; Matsumoto, Yoshihiro*; Parker, J. D.*; Nakatani, Takeshi; Hiroi, Kosuke; Su, Y. H.; et al.
JPS Conference Proceedings (Internet), 22, p.011028_1 - 011028_8, 2018/11
Hiroi, Kosuke; Shinohara, Takenao; Hayashida, Hirotoshi*; Parker, J. D.*; Oikawa, Kenichi; Su, Y. H.; Kai, Tetsuya; Kiyanagi, Yoshiaki*
JPS Conference Proceedings (Internet), 22, p.011030_1 - 011030_7, 2018/11
Sato, Hirotaka*; Shiota, Yoshinori*; Morooka, Satoshi; Todaka, Yoshikazu*; Adachi, Nozomu*; Sadamatsu, Sunao*; Oikawa, Kenichi; Harada, Masahide; Zhang, S.*; Su, Y. H.; et al.
Journal of Applied Crystallography, 50(6), p.1601 - 1610, 2017/12
Times Cited Count：20 Percentile：80.01(Chemistry, Multidisciplinary)Kai, Tetsuya; Hiroi, Kosuke; Su, Y. H.; Shinohara, Takenao; Parker, J. D.*; Matsumoto, Yoshihiro*; Hayashida, Hirotoshi*; Segawa, Mariko; Nakatani, Takeshi; Oikawa, Kenichi; et al.
Physics Procedia, 88, p.306 - 313, 2017/06
Times Cited Count：7 Percentile：91.22(Instruments & Instrumentation)Su, Y. H.; Oikawa, Kenichi; Shinohara, Takenao; Kai, Tetsuya; Hiroi, Kosuke; Harjo, S.; Kawasaki, Takuro; Gong, W.; Zhang, S. Y.*; Parker, J. D.*; et al.
Physics Procedia, 88, p.42 - 49, 2017/06
Times Cited Count：5 Percentile：85.95(Instruments & Instrumentation)
