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Nakajima, Taro*; Inamura, Yasuhiro; Ito, Takayoshi*; Oishi, Kazuki*; Oike, Hiroshi*; Kagawa, Fumitaka*; Kikkawa, Akiko*; Taguchi, Yasujiro*; Kakurai, Kazuhisa*; Tokura, Yoshinori*; et al.
Physical Review B, 98(1), p.014424_1 - 014424_5, 2018/07
Times Cited Count:5 Percentile:34.98(Materials Science, Multidisciplinary)We investigated the phase-transition kinetics of magnetic skyrmion lattice (SkL) in MnSi by means of stroboscopic small-angle neutron scattering (SANS). Temporal evolutions of SANS patterns were measured with time resolution of 13 ms while sweeping temperature as fast as 50 Ks. It turned out that the paramagnetic-to-SkL transition immediately occurs upon traversing the equilibrium phase boundary on the rapid cooling, whereas the SkL-to-conical transition can be kinetically avoided to realize the low-temperature metastable SkL with a long-range magnetic order. The formation of the metastable SkL was found to be strongly dependent not only on cooling rate, but also on magnetic eld and trajectory in the H-T phase diagram.
Tochio, Daisuke; Honda, Yuki; Sato, Hiroyuki; Sekita, Kenji; Homma, Fumitaka; Sawahata, Hiroaki; Takada, Shoji; Nakagawa, Shigeaki
Journal of Nuclear Science and Technology, 54(1), p.13 - 21, 2017/01
Times Cited Count:1 Percentile:10.71(Nuclear Science & Technology)GTHTR300C is designed and developed in JAEA. The reactor system is required to continue a stable and safety operation as well as a stable power supply in the case that thermal-load is fluctuated by the occurrence of abnormal event in the heat utilization system. Then, it is necessary to demonstrate that the thermal-load fluctuation should be absorbed by the reactor system so as to continue the stable and safety operation could be continued. The thermal-load fluctuation absorption tests without nuclear heating were planned and conducted in JAEA to clarify the absorption characteristic of thermal-load fluctuation mainly by the reactor and by the IHX. As the result it was revealed that the reactor has the larger absorption capacity of thermal-load fluctuation than expected one, and the IHX can be contributed to the absorption of the thermal-load fluctuation generated in the heat utilization system in the reactor system. It was confirmed from there result that the reactor and the IHX has effective absorption capacity of the thermal-load fluctuation generated in the heat utilization system. Moreover it was confirmed that the safety estimation code based on RELAP5/MOD3 can represents the thermal-load fluctuation absorption behavior conservatively.
Honda, Yuki; Tochio, Daisuke; Nakagawa, Shigeaki; Sekita, Kenji; Homma, Fumitaka; Sawahata, Hiroaki; Sato, Hiroyuki; Sakaba, Nariaki; Takada, Shoji
JAEA-Technology 2016-016, 16 Pages, 2016/08
A system analysis code is validated with the thermal-load fluctuation absorption test with nun-nuclear heating by using the High Temperature Engineering test Reactor (HTTR) to clarify the High Temperature Gas-cooled Reactor (HTGR) system response against temperature transient. The thermal-load fluctuation absorption test consists on the thermal load fluctuation tests (non-nuclear heating) and heat application system abnormal simulating test (non-nuclear heating). The HTGR reactor response against temperature transient is clarified in the thermal load fluctuation test (non-nuclear heating). The Intermediate Heat Exchanger (IHX) reactor response against temperature transient is clarified in the heat application system abnormal simulating test (non-nuclear heating). With the two HTTR non-nuclear heating test, HTGR system response against temperature transient is obtained.
Taguchi, Yasujiro*; Sakai, Hideaki*; Okuyama, Daisuke*; Ishiwata, Shintaro*; Fujioka, Jun*; Fukuda, Tatsuo; Hashizume, Daisuke*; Kagawa, Fumitaka*; Takahashi, Yoichiro*; Shimano, Ryo*; et al.
Physica B; Condensed Matter, 407(11), p.1685 - 1688, 2012/06
Times Cited Count:5 Percentile:24.08(Physics, Condensed Matter)Takeda, Takeshi; Nakagawa, Shigeaki; Homma, Fumitaka*; Takada, Eiji*; Fujimoto, Nozomu
Journal of Nuclear Science and Technology, 39(9), p.986 - 995, 2002/09
Times Cited Count:4 Percentile:29.29(Nuclear Science & Technology)no abstracts in English
Nakagawa, Shigeaki; Saito, Kenji; Homma, Fumitaka; Tachibana, Yukio; Kunitomi, Kazuhiko
JAERI-Tech 2000-009, p.88 - 0, 2000/02
no abstracts in English
Ota, Nobuaki*; Nakagawa, Seiko*; Nishiyama, Fumitaka*; Morishita, Norio; Oshima, Takeshi
no journal, ,
A bulk with 0.5-1 mm thickness of polyaniline was irradiated by the 3MV Tandem accelerator at the Takasaki Ion Accelerators for Advanced Radiation Application (TIARA) facility. ESR spectra of N or P doped polyaniline were measured at 77 K. A broad peak of polyaniline radical was observed. Except for polyaniline radical, new signals were also appeared when the fluence of doped N was less than 210ions/cm and that of P was more than 610ions/cm.