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Sumida, Kazuki; Kusaka, Shotaro*; Takeda, Yukiharu; Kobayashi, Katsuyoshi*; Hirahara, Toru*
Physical Review B, 106(19), p.195421_1 - 195421_7, 2022/11
Times Cited Count:1 Percentile:14.73(Materials Science, Multidisciplinary)Kusaka, Shotaro*; Sasaki, Taisuke*; Sumida, Kazuki; Ichinokura, Satoru*; Ideta, Shinichiro*; Tanaka, Kiyohisa*; Hono, Kazuhiro*; Hirahara, Toru*
Applied Physics Letters, 120(17), p.173102_1 - 173102_5, 2022/04
Times Cited Count:2 Percentile:30.40(Physics, Applied)Sumida, Kazuki; Takeda, Yukiharu; Kusaka, Shotaro*; Kobayashi, Katsuyoshi*; Hirahara, Toru*
Physical Review Materials (Internet), 6(1), p.014006_1 - 014006_8, 2022/01
Times Cited Count:6 Percentile:61.59(Materials Science, Multidisciplinary)We investigated the intrinsic magnetic properties of the two-dimensional ferromagnetic candidate monolayer 1-VSe films using X-ray magnetic circular dichroism (XMCD), an element-specific magnetic probe. By performing high-resolution measurements, we succeeded in detecting a clear XMCD signal from the atomically thin 1-VSe films under an external magnetic field. Through manipulation of the X-ray incidence angle, we were able to disentangle the in-plane and out-of-plane magnetic properties and found a strong magnetic anisotropy. Moreover, magnetic field- and temperature-dependent XMCD revealed that there is no long-range ferromagnetic ordering even at 6 K, but short-range ferromagnetic and antiferromagnetic interactions between neighboring vanadium ions exist. Such low-temperature magnetic behavior signifies that the monolayer 1-VSe is on the verge of ferromagnetism, and this fact accounts for the reported ferromagnetism in VSe-based heterostructures.
Fukasawa, Takuro*; Kusaka, Shotaro*; Sumida, Kazuki; Hashizume, Mizuki*; Ichinokura, Satoru*; Takeda, Yukiharu; Ideta, Shinichiro*; Tanaka, Kiyohisa*; Shimizu, Ryota*; Hitosugi, Taro*; et al.
Physical Review B, 103(20), p.205405_1 - 205405_6, 2021/05
Times Cited Count:9 Percentile:63.89(Materials Science, Multidisciplinary)Hirahara, Toru*; Otrokov, M. M.*; Sasaki, Taisuke*; Sumida, Kazuki*; Tomohiro, Yuta*; Kusaka, Shotaro*; Okuyama, Yuma*; Ichinokura, Satoru*; Kobayashi, Masaki*; Takeda, Yukiharu; et al.
Nature Communications (Internet), 11, p.4821_1 - 4821_8, 2020/09
Times Cited Count:42 Percentile:93.04(Multidisciplinary Sciences)Fukaya, Yuki; Kubo, Keisuke*; Hirahara, Toru*; Yamazaki, Shiro*; Choi, W. H.*; Yeom, H. W.*; Kawasuso, Atsuo; Hasegawa, Shuji*; Matsuda, Iwao*
e-Journal of Surface Science and Nanotechnology (Internet), 10, p.310 - 314, 2012/07
no abstracts in English
Fukaya, Yuki; Matsuda, Iwao*; Hashimoto, Mie*; Kubo, Keisuke*; Hirahara, Toru*; Yamazaki, Shiro*; Choi, W. H.*; Yeom, H. W.*; Hasegawa, Shuji*; Kawasuso, Atsuo; et al.
Surface Science, 606(11-12), p.919 - 923, 2012/06
Times Cited Count:6 Percentile:28.10(Chemistry, Physical)no abstracts in English
Cheng, S.*; Hirahara, Daisuke*; Tanaka, Yohei*; Gondai, Yoji*; Zhang, B.*; Matsumoto, Tatsuya*; Morita, Koji*; Fukuda, Kenji*; Yamano, Hidemasa; Suzuki, Toru; et al.
Experimental Thermal and Fluid Science, 35(2), p.405 - 415, 2011/02
Times Cited Count:30 Percentile:76.40(Thermodynamics)The current experiments were conducted under two dimensional (2D) and three dimensional (3D) conditions separately, in which water was used as liquid phase, and bubbles were generated by injecting nitrogen gas from the bottom of the viewing tank. Various particle-bed parameters were varied, including particle-bed height (from 30 mm to 200 mm), particle diameter (from 0.4 mm to 6 mm) and particle type (beads made of acrylic, glass, alumina and zirconia). Under these experimental conditions, three kinds of bubbling behavior were observed for the first time using digital image analysis methods that were further verified by quantitative detailed analysis of bubbling properties including surface bubbling frequency and surface bubble size under both 2D and 3D conditions.
Zhang, B.*; Harada, Tetsushi*; Hirahara, Daisuke*; Matsumoto, Tatsuya*; Morita, Koji*; Fukuda, Kenji*; Yamano, Hidemasa; Suzuki, Toru; Tobita, Yoshiharu
Nuclear Engineering and Design, 241(1), p.366 - 377, 2011/01
Times Cited Count:37 Percentile:92.91(Nuclear Science & Technology)Matsuda, Iwao*; Nakamura, Fumitaka*; Kubo, Keisuke*; Hirahara, Toru*; Yamazaki, Shiro*; Choi, W. H.*; Yeom, H. W.*; Narita, Hisashi*; Fukaya, Yuki; Hashimoto, Mie*; et al.
Physical Review B, 82(16), p.165330_1 - 165330_6, 2010/10
Times Cited Count:9 Percentile:40.49(Materials Science, Multidisciplinary)no abstracts in English
Cheng, S.*; Hirahara, Daisuke*; Tanaka, Yohei*; Gondai, Yoji*; Matsumoto, Tatsuya*; Morita, Koji*; Fukuda, Kenji*; Yamano, Hidemasa; Suzuki, Toru; Tobita, Yoshiharu
Proceedings of 18th International Conference on Nuclear Engineering (ICONE-18) (CD-ROM), 8 Pages, 2010/05
A series of experiments on bubble behavior in a particle bed was performed to clarify three-phase flow dynamics in debris bed, which is essential in heat-removal capability, under coolant boiling conditions. The current experiment was conducted in a 2D tank. Water was used as liquid phase, while bubbles were generated by injecting nitrogen gas from the bottom of the tank. Various experimental parameters were taken, including different particle bed height, various particle diameter, different particle type, and different nitrogen gas flow rate. By using digital image analysis method, three kinds of bubble rise behavior were observed under current experimental conditions and confirmed by the quantitative detailed analysis of bubble rise properties including bubble departure frequency and bubble departure size.
Zhang, B.*; Harada, Tetsushi*; Hirahara, Daisuke*; Matsumoto, Tatsuya*; Morita, Koji*; Fukuda, Kenji*; Yamano, Hidemasa; Suzuki, Toru; Tobita, Yoshiharu
Journal of Nuclear Science and Technology, 47(4), p.384 - 395, 2010/04
Times Cited Count:40 Percentile:92.43(Nuclear Science & Technology)Zhang, B.*; Harada, Tetsushi*; Hirahara, Daisuke*; Matsumoto, Tatsuya*; Morita, Koji*; Fukuda, Kenji*; Yamano, Hidemasa; Suzuki, Toru; Tobita, Yoshiharu
Proceedings of 13th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-13) (CD-ROM), 15 Pages, 2009/09
Although the decay heat from fuel debris drives the coolant boiling in fast reactor accident conditions, the present experiments were conducted by employing depressurization boiling of water to simulate axially increasing void distribution in a debris bed instead of conventional heating or gas injection from the debris bottom. Good agreements on self-leveling occurrence were obtained between model predictions and experimental results. Extrapolation of the present model was also discussed against reactor conditions.
Zhang, B.*; Harada, Tetsushi*; Hirahara, Daisuke*; Matsumoto, Tatsuya*; Morita, Koji*; Fukuda, Kenji*; Yamano, Hidemasa; Suzuki, Toru; Tobita, Yoshiharu
Proceedings of 6th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-6) (USB Flash Drive), 8 Pages, 2008/11
In the present study, characteristics of self-leveling behaviors were investigated experimentally with simulant materials. The present experiments employed depressurization boiling of water to simulate axially increasing void distribution in a debris bed, which consists of solid particles of alumina or lead with different density. The particle size (from 0.5 mm to 6 mm in diameter) and shape (spherical or non-spherical particles) were also taken as experimental parameters. A rough criteria for self-leveling occurrence is proposed and compared with the experimental results.
Sumida, Kazuki; Kusaka, Shotaro*; Takeda, Yukiharu; Kobayashi, Katsuyoshi*; Hirahara, Toru*
no journal, ,
no abstracts in English
Sumida, Kazuki; Takeda, Yukiharu; Kusaka, Shotaro*; Kobayashi, Katsuyoshi*; Hirahara, Toru*
no journal, ,
Harada, Tetsushi*; Hirahara, Daisuke*; Zhang, B.*; Matsumoto, Tatsuya*; Morita, Koji*; Fukuda, Kenji*; Suzuki, Toru; Yamano, Hidemasa; Tobita, Yoshiharu
no journal, ,
no abstracts in English
Sumida, Kazuki; Takeda, Yukiharu; Kusaka, Shotaro*; Kobayashi, Katsuyoshi*; Hirahara, Toru*
no journal, ,
no abstracts in English