ToF inelastic neutron scattering studies on quantum spin systems (CuCl)LaO ( = Nb, Ta)

Kawamura, Seiko; Nakajima, Kenji; Inamura, Yasuhiro; Tsujimoto, Yoshihiro*; Kitada, Atsushi*; Takeiri, Fumitaka*; Kageyama, Hiroshi*; Ajiro, Yoshitami*; Nishi, Masakazu*; Kakurai, Kazuhisa

Journal of Physics; Conference Series, 320, p.012037_1 - 012037_5, 2011/09

https://doi.org/10.1088/1742-6596/320/1/012037

The magnetic ground state of (CuCl)LaNbO has been suggested to be a spin-singlet state with an excitation gap of meV, while (CuCl)LaTaO has an antiferromagnetic (AFM) ground state. The systems are suspected to be a frustrated quantum spin system due to the competition between the nearest and next-nearest exchange interactions. We have studied magnetic excitation in these systems by ToF inelastic neutron scattering technique. The measurements were performed on powder samples of (CuCl)LaNbO and (CuCl)LaTaO at a disk-chopper-type spectrometer AMATERAS in J-PARC. In both systems, a band-like excitation was observed at meV. The dependence of the intensity of magnetic excitation around 2 meV for (CuCl)LaNbO well reproduces that observed at a triple-axis spectrometer, exhibiting characteristics of spin-singlet dimers. On the other hand, (CuCl)LaTaO in the AFM state exhibits a different dependence.

Ion beam breeding of sugarcane cultivar "Ni17"

Takenoshita, Yoshihisa*; Tojima, Futoshi*; Nishi, Hiroyuki*; Shirao, Tsukasa*; Nagatani, Takeshi*; Oe, Masakazu*; Hase, Yoshihiro; Narumi, Issei

JAEA-Review 2008-055, JAEA Takasaki Annual Report 2007, P. 66, 2008/11

https://jopss.jaea.go.jp/pdfdata/JAEA-Review-2008-055.pdf

no abstracts in English

Development of stress conditions around a tunnel excavated in argillaceous rock related to change of saturation conditions

Uehara, Shinichi*; Kobayashi, Akira*; Chijimatsu, Masakazu*; Onishi, Yuzo*; Fujita, Tomoo

Proceedings of 2nd International Conference on Coupled T-H-M-C Processes in Geo-systems; Fundamentals, Modeling, Experiments and Applications (GeoProc 2006), p.738 - 743, 2006/05

This paper reports the results of calculations about coupled hydro-mechanical process in the domain around excavations at clay rock site at Tournemire, France. We operated the numerical modelling by using a Finite Element Method code named THAMES, on the assumption that swelling pressure is parallel to saturation ratio. The results of modelling indicated that saturation ratio changes seasonally at the domain within several tens cm from tunnel wall. This extension is similar to that of damage zone observed in the tunnel at Tournemire site in 1881, which supports the idea that the saturation-desaturation cycles has decreased the rock strength and caused damage zone extension. The modelling results also suggested that the consideration of swelling pressure could affect evolution of stress state abruptly.

Neutron scattering investigation on quantum spin system SrCu(BO)

Kakurai, Kazuhisa; Nukui, Katsuyuki*; Aso, Naofumi*; Nishi, Masakazu*; Kadowaki, Hiroaki*; Kageyama, Hiroshi*; Ueda, Yutaka*; Regnault, L.-P.*; Cpas, O.*

Progress of Theoretical Physics Supplement, (159), p.22 - 32, 2005/10

no abstracts in English

Highly polarized electrons from GaAs-GaAsP and InGaAs-AlGaAs strained-layer superlattice photocathodes

Nishitani, Tomohiro; Nakanishi, Tsutomu*; Yamamoto, Masahiro*; Okumi, Shoji*; Furuta, Fumio*; Miyamoto, Masaharu*; Kuwahara, Makoto*; Yamamoto, Naoto*; Naniwa, Kenichi*; Watanabe, Osamu*; et al.

Journal of Applied Physics, 97(9), p.094907_1 - 094907_6, 2005/05

https://doi.org/10.1063/1.1886888

no abstracts in English

Effect of coupling behavior of the near fild on groundwater flow of the far field for geological disposal of high level radioactive waste

Kurikami, Hiroshi; Kobayashi, Akira*; Chijimatsu, Masakazu*; Sugita, Yutaka; Onishi, Yuzo*

Proceedings of International Conference on Coupled T-H-M-C Processes in Geo-systems; Fundamentals, Modelling, Experiments and Applications (GeoProc 2003), p.403 - 408, 2003/00

It is very important in performance assessment to estimate the impact of constructing high-level radioactive waste repositories deep underground on the regional groundwater flow system. This paper proposes a method of estimating the impact of coupled t

Development of electrochemical hydrogen pump under vacuum condition for a compact tritium gas cycling system

Kato, Mineo; Ito, Takeshi*; Sugai, Hiroyuki; Kawamura, Yoshinori; Hayashi, Takumi; Nishi, Masataka; Tanase, Masakazu; Matsuzaki, Teiichiro*; Ishida, Katsuhiko*; Nagamine, Kanetada*

Fusion Science and Technology, 41(3), p.859 - 862, 2002/05

JAERI has a plane to develop a compact tritium gas recycling system for fusion research. This system is also very attractive for the muon-catalyzed fusion (CF) research at RIKEN-RAL Muon Facility in UK. For the research, JAERI has produced high purity tritium gas of 1,500 Ci and transported it to the Facility. In the CF experiments, the tritium gas was diluted by the deuterium in an optional concentration and the used tritium gas was carried back by the tritium transport container developed to JAERI. If it is possible to recycle the diluted tritium gas, i.e., the used tritium gas is enriched in the experimental site, the CF experiments should be conducted efficiently. rom the above point of view, in this paper, we propose the compact tritium gas recycling system based on the gas chromatography that has already developed in JAERI and a proton conductor.

Partially disordered antiferromagnetic phase in CaCoRhO

Niitaka, Seiji*; Yoshimura, Kazuyoshi*; Kosuge, K.*; Nishi, Masakazu*; Kakurai, Kazuhisa

Physical Review Letters, 87(17), p.177202_1 - 177202_4, 2001/10

https://doi.org/10.1103/PhysRevLett.87.177202

no abstracts in English

Incommensurate magnetic ordering and spin-liquid-like state in a triangular lattice BaVS; Neutron diffraction and scattering study

Nakamura, Hiroyuki*; Yamasaki, Tomoaki*; Giri, S.*; Imai, Hideto*; Shiga, Masayuki*; Kojima, Kenji*; Nishi, Masakazu*; Kakurai, Kazuhisa*; Metoki, Naoto

Journal of the Physical Society of Japan, 69(9), p.2763 - 2766, 2000/09

https://doi.org/10.1143/JPSJ.69.2763

no abstracts in English

Coupled Thermo-Hydro-Mechanical Experiment at Kamaishi Mine Technical Note 16-99-03, Analyses of Task 2C, DECOVALEXII

Chijimatsu, Masakazu*; Fujita, Tomoo; Kobayashi, Akira*; Onishi, Yuzo*

JNC TN8400 99-031, 61 Pages, 1999/06

JNC-TN8400-99-031.pdf:3.36MB

It is an important part of the near field performance assessment of nuclear waste disposal to evaluate couples thermo-hydro-mechanical (T-H-M) phenomena, e.g., thermal effects on groundwater flow through rock matrix and water seepage into the buffer material, the generation of swelling pressure of the buffer material, and thermal stresses potentially affecting porosity and fracture apertures of the rock. An in-situ T-H-M experiment naned 'Engineered Barrier Experiment' has been oonducted at the Kamaishi Mine, of which host rock is granodiorite, in order to establish conceptual models of the coupled T-H-M processes and to build confidence in mathematical models and computer codes. The coupled T-H-M experiment is one of tasks in DECOVALEX (DEvelopment of COupled models and their VALidation against EXperiments) project which is an international co-operative project and it is defined as Task 2. The Task 2 for the DECOVALEX project are divided into three subtasks (A-C) in accordance with the programme and availability of data, called subtasks. This note describes the results of subtask C. Subtask C is a coupled thermo-hydro-mechanical analysis in the near field.