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Tokunaga, Yo; Saito, Yo*; Sakai, Hironori; Kambe, Shinsaku; Sanada, Naoyuki*; Watanuki, Ryuta*; Suzuki, Kazuya*; Kawasaki, Yu*; Kishimoto, Yutaka*
Physical Review B, 84(21), p.214403_1 - 214403_7, 2011/12
Times Cited Count:9 Percentile:37.97(Materials Science, Multidisciplinary)We report NMR studies of TbCoGa, which has the tetragonal HoCoGa
structure and exhibits two antiferromagnetic (AF) transitions at
=36.2 K and
=5.4 K. From a symmetry analysis of internal magnetic fields at orthorhombic Ga sites, we have successfully determined the magnetic structures in the AF-I (
) and AF-II (
) phases. The AF-I phase is a collinear AF order with a propagation vector
and ordered moments parallel to the [001] direction. In the AF-II phase, on the other hand, we found a non-collinear AF structure described by double propagation vectors
and
, where the moments tilt away from the [001] direction toward [100], keeping a constant value along the [001] direction. In the context of these results we discuss the possible presence of magnetic frustration in this system.
Nakamura, Takahiro; Sanada, Hiroyuki; Sugita, Yutaka; Teshima, Minoru*; Kasagi, Toshio*; Kishimoto, Munemaru*; Deguchi, Tomonori*; Makuuchi, Ayumu*
JAEA-Research 2010-006, 68 Pages, 2010/06
The present document is to report the result of geophysical survey by electric survey around a site proposed for the Horonobe Underground Research Laboratory Project at Horonobe-cho, Hokkaido by the Japan Atomic Energy Agency. This Electric survey using pole-pole array in Horonobe Underground Research Laboratory Area was the third survey. Resistivity distribution near surface was about 20 m and it become to about 2
m as the depth increasing. Resistivity distribution was good agreement with existing survey results and existing electrical resistivity log data. By comparing resistivity model with hydrology model, it was confirmed that resistivity reflected the density of salinity. The range and distribution trends of apparent resistivity in this year were similar to the results of last year. It is thought that the data in which reproducibility is high is acquired in this survey. The influence on the underground water flow by construction is not admitted now.
Nakamura, Takahiro; Sanada, Hiroyuki; Sugita, Yutaka; Teshima, Minoru*; Kishimoto, Munemaru*; Matsuo, Koichi*
JAEA-Research 2008-102, 58 Pages, 2009/03
The present document is to report the result of geophysical survey by electric survey around a site proposed for the Horonobe Underground Research Laboratory Project at Horonobe-cho, Hokkaido by the Japan Atomic Energy Agency. This Electric survey using pole-pole array in Horonobe Underground Research Laboratory Area was the second survey. Resistivity distribution near surface was about 20 ohm-m and it become to about 2 ohm-m as the depth increasing. Resistivity distribution was good agreement with existing survey results and existing electrical resistivity log data. By comparing resistivity model with hydrology model, it was confirmed that resistivity reflected the density of salinity. The range and distribution trends of apparent resistivity in this year were similar to the results of last year. It is thought that the data in which reproducibility is high is acquired in this survey. The influence on the underground water flow by construction is not admitted now.
Doyle, E. J.*; Houlberg, W. A.*; Kamada, Yutaka; Mukhovatov, V.*; Osborne, T. H.*; Polevoi, A.*; Bateman, G.*; Connor, J. W.*; Cordey, J. G.*; Fujita, Takaaki; et al.
Nuclear Fusion, 47(6), p.S18 - S127, 2007/06
no abstracts in English
Takenaga, Hidenobu; Kubo, Hirotaka; Kamada, Yutaka; Miura, Yukitoshi; Kishimoto, Yasuaki; Ozeki, Takahisa
Fusion Science and Technology, 50(4), p.503 - 507, 2006/11
Times Cited Count:3 Percentile:23.75(Nuclear Science & Technology)no abstracts in English
Kikuchi, Mitsuru; Tamai, Hiroshi; Matsukawa, Makoto; Fujita, Takaaki; Takase, Yuichi*; Sakurai, Shinji; Kizu, Kaname; Tsuchiya, Katsuhiko; Kurita, Genichi; Morioka, Atsuhiko; et al.
Nuclear Fusion, 46(3), p.S29 - S38, 2006/03
Times Cited Count:13 Percentile:40.87(Physics, Fluids & Plasmas)The National Centralized Tokamak (NCT) facility program is a domestic research program for advanced tokamak research to succeed JT-60U incorporating Japanese university accomplishments. The mission of NCT is to establish high beta steady-state operation for DEMO and to contribute to ITER. The machine flexibility and mobility is pursued in aspect ratio and shape controllability, feedback control of resistive wall modes, wide current and pressure profile control capability for the demonstration of the high-b steady state.
Fukuda, Yuji; Akahane, Yutaka; Aoyama, Makoto; Inoue, Norihiro*; Ueda, Hideki; Kishimoto, Yasuaki; Yamakawa, Koichi; Faenov, A. Y.*; Magunov, A. I.*; Pikuz, T. A.*; et al.
Laser and Particle Beams, 22(3), p.215 - 220, 2004/07
Times Cited Count:42 Percentile:79.03(Physics, Applied)High resolution K-shell spectra of a plasma created by superintense laser irradiation of micron-sized Ar clusters have been measured with an intensity above 10 W/cm
and a pulse duration of 30 fs. The total photon flux of 2
10
photons/pulse was achieved for He
resonant line of Ar (
=3.9491 AA , 3.14 keV). In parallel with X-ray measurements, energy distributions of emitted ions have been measured. The multiply-charged ions with kinetic energies up to 800 keV were observed. It is found that hot electrons produced by high contrast laser pulses allow the isochoric heating of clusters and shift the ion balance towards the higher charge states, which enhances both the X-ray line yield of the He-like argon ion and the ion kinetic energy.
Fukuda, Yuji; Akahane, Yutaka; Aoyama, Makoto; Inoue, Norihiro*; Ueda, Hideki; Kishimoto, Yasuaki; Yamakawa, Koichi; Faenov, A. Y.*; Magunov, A. I.*; Pikuz, T. A.*; et al.
Laser-Generated & Other Lab. X-Ray & EUV Sources (Proceedings of SPIE Vol.5196), p.234 - 243, 2004/00
High resolution X-ray emission spectra of plasma created by laser irradiation of rare-gas (Ar, Kr, Xe) clusters have been measured at laser intensities over 10 W/cm
and 30-fs pulse duration. To make these measurements possible, in addition to the effort to decrease a prepulse intensity using Pockels cell switches, micron-size clusters were produced using a specially designed conical nozzle. The Boltzmann equation and a detailed collisional radiative model are solved simultaneously as a function of time to model the time integrated X-ray spectra of the transient plasma. The results are quantitatively in good agreement with the experimentally observed X-ray emission spectra of Ar clusters.
Fukuda, Yuji; Yamakawa, Koichi; Akahane, Yutaka; Aoyama, Makoto; Inoue, Norihiro*; Ueda, Hideki; Kishimoto, Yasuaki
Physical Review A, 67(6), p.061201_1 - 061201_4, 2003/06
Times Cited Count:59 Percentile:88.60(Optics)We have probed the interaction of intense laser fields with Xe clusters by measuring the energy and charge state distributions of emitted ions and electrons using ultrafast 20 fs pulses. This work demonstrates that the energetic particle emissions from laser-cluster interactions can be optimized by manipulating the character of ultrafast laser pulses, i.e. pulse duration and sign of chirp.
Ueshima, Yutaka; Sentoku, Yasuhiko*; Kishimoto, Yasuaki
Nuclear Instruments and Methods in Physics Research A, 455(1), p.181 - 184, 2000/11
Times Cited Count:17 Percentile:71.50(Instruments & Instrumentation)no abstracts in English
Ueshima, Yutaka; Kishimoto, Yasuaki
Proceedings of 3rd International Symposium on High Performance Computing, p.524 - 534, 2000/00
no abstracts in English
Ueshima, Yutaka; Sentoku, Yasuhiko*; Kishimoto, Yasuaki
Proceedings of 4th International Conference on Supercomputing in Nuclear Applications (SNA 2000) (CD-ROM), 10 Pages, 2000/00
no abstracts in English
Yamagiwa, Mitsuru; Koga, J. K.; L.N.Tsintsadze*; Ueshima, Yutaka*; Kishimoto, Yasuaki
Physical Review E, 60(5), p.5987 - 5990, 1999/11
Times Cited Count:19 Percentile:62.48(Physics, Fluids & Plasmas)no abstracts in English
Shirai, Hiroshi; Kikuchi, Mitsuru; Takizuka, Tomonori; Fujita, Takaaki; Koide, Yoshihiko; Rewoldt, G.*; Mikkelsen, D. R.*; Budny, R.*; Tang, W. M.*; Kishimoto, Yasuaki; et al.
Fusion Energy 1998, 2, p.405 - 412, 1999/00
no abstracts in English
Ueshima, Yutaka*; Arakawa, Takuya*; Kishimoto, Yasuaki; Sasaki, Akira; Tajima, Toshiki*
Inst. Phys. Conf. Ser., (159), p.325 - 328, 1999/00
no abstracts in English
Shirai, Hiroshi; Kikuchi, Mitsuru; Takizuka, Tomonori; Fujita, Takaaki; Koide, Yoshihiko; Rewoldt, G.*; Mikkelsen, D. R.*; Budny, R.*; Tang, W. M.*; Kishimoto, Yasuaki; et al.
Nuclear Fusion, 39(11Y), p.1713 - 1722, 1999/00
Times Cited Count:69 Percentile:87.05(Physics, Fluids & Plasmas)no abstracts in English
Ueshima, Yutaka*; Kishimoto, Yasuaki; Sasaki, Akira; Moribayashi, Kengo*; Nagashima, Keisuke; Kado, Masataka; Sagisaka, Akito*; Tajima, Toshiki*
JAERI-Research 98-048, 46 Pages, 1998/08
no abstracts in English
Ozeki, Takahisa; Azumi, Masafumi; Ishii, Yasutomo; Kishimoto, Yasuaki; G.Y.Fu*; Fujita, Takaaki; G.Rewoldt*; Kikuchi, Mitsuru; Kamada, Yutaka; Ide, Shunsuke; et al.
Plasma Physics and Controlled Fusion, 39(5A), p.A371 - A380, 1997/05
no abstracts in English
; ; ; Kitahara, Yoshihisa*; Kishimoto, Yoichiro; Yamato, Aiji; ; ; ; ; et al.
PNC TN841 78-69VOL1, 127 Pages, 1978/12
no abstracts in English
Tokunaga, Yo; Saito, Yo*; Sakai, Hironori; Kambe, Shinsaku; Sanada, Naoyuki*; Watanuki, Ryuta*; Suzuki, Kazuya*; Kawasaki, Yu*; Kishimoto, Yutaka*
no journal, ,
We report NMR studies of TbCoGa, which has the tetragonal HoCoGa
structure and exhibits two antiferromagnetic (AF) transitions at
=36.2 K and
=5.4 K. From analysis of the internal fields at Ga sites, we have determined the magnetic structures of the AF-I (
) and the AF-II (
) phases. The AF-I phase is a collinear AF order with the propagation vector q=[1/2, 0, 1/2] and with ordered moments parallel to the c axis. This is in accordance with the neutron diffraction measurements. In the AF-II phase, on the other hand, we found a non-collinear AF structure described with double propagation vectors
=[1/2, 0, 1/2] and
=[0, 1/2, 1/2]. Interestingly, the NMR reveals that the c component of the Tb moments does not change value between the AF-I and the AF-II phases, even though an a component is newly developed in the AF-II phase.
Meguro, Yoshihiro; Kato, Jun; Kishimoto, Katsumi; Kameo, Yutaka; Ishimori, Kenichiro; Tanaka, Kiwamu; Shibata, Atsuhiro; Koma, Yoshikazu; Ashida, Takashi
no journal, ,
The authors are working in study for radioactive wastes generated in Fukushima Daiichi. Radioactive inventory estimation of wastes is important in the study for the processing and disposal of radioactive waste. And then so many real wastes have to be analyzed for their inventory evaluation. In addition to this waste analysis, there are several needs for analysis. For example a large volume of the contaminated water is being decontaminated, and operational status and ability of this system should be checked by analysis of the treated water. And also groundwater and sea water are analyzing to understand contaminated situation, to estimate a leakage position, and to confirm leakage prevention. In future fuel debris will be analyzed for its material accountancy. In this presentation, actual situation of analyses in Fukushima Daiichi will be explained, mainly focus on analyses for the inventory evaluation of the radioactive waste.