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Soda, Minoru*; Kofu, Maiko; Kawamura, Seiko; Asai, Shinichiro*; Masuda, Takatsugu*; Yoshizawa, Hideki*; Furukawa, Hazuki*
Journal of the Physical Society of Japan, 91(9), p.094707_1 - 094707_5, 2022/09
Times Cited Count:0 Percentile:0(Physics, Multidisciplinary)Okuma, Ryutaro*; Kofu, Maiko; Asai, Shinichiro*; Avdeev, M.*; Koda, Akihiro*; Okabe, Hirotaka*; Hiraishi, Masatoshi*; Takeshita, Soshi*; Kojima, Kenji*; Kadono, Ryosuke*; et al.
Nature Communications (Internet), 12, p.4382_1 - 4382_7, 2021/07
Times Cited Count:5 Percentile:67.76(Multidisciplinary Sciences)Asai, Shinichiro*; Okazaki, Ryuji*; Terasaki, Ichiro*; Yasui, Yukio*; Igawa, Naoki; Kakurai, Kazuhisa
JPS Conference Proceedings (Internet), 3, p.014034_1 - 014034_6, 2014/06
We have carried out the neutron scattering measurements for a single crystal of LaCoRh
O
in order to investigate the ferromagnetic ordering induced by Rh
substitution for Co
of LaCoO
. The ordered moment is evaluated to be 0.4
0.2
, which is consistent with the saturation magnetization of LaCo
Rh
O
. It indicates that the ferromagnetic ordering of LaCo
Rh
O
originates from the short-range ferromagnetic ordering disordered by Rh
ions.
Asai, Shinichiro*; Okazaki, Ryuji*; Terasaki, Ichiro*; Yasui, Yukio*; Kobayashi, Wataru*; Nakao, Akiko*; Kobayashi, Kensuke*; Kumai, Reiji*; Nakao, Hironori*; Murakami, Yoichi*; et al.
Journal of the Physical Society of Japan, 82(11), p.114606_1 - 114606_6, 2013/11
Times Cited Count:6 Percentile:44.56(Physics, Multidisciplinary)Neutron and synchrotron X-ray diffraction for LaCo Rh
O
have been carried out in order to investigate the structural properties related with the spin state of Co
ions. We have found that the values of the Co(Rh)-O bond lengths in the Co(Rh)O
octahedron of LaCo
Rh
O
are nearly identical at 10 K. The lattice volume for the Rh
substituted samples decreases with the thermal expansion coefficient similar to that of LaCoO
from room temperature, and ceases to decrease around 70 K. These experimental results favor a mixed state consisting of the high-spin state and low-spin state Co
ions, and suggest that the high-spin state Co
ions are thermally excited in addition to those pinned by the substituted Rh
ions.
Mikake, Shinichiro; Yamamoto, Masaru; Ikeda, Koki; Sugihara, Kozo; Takeuchi, Shinji; Hayano, Akira; Sato, Toshinori; Takeda, Shinichi; Ishii, Yoji; Ishida, Hideaki; et al.
JAEA-Technology 2010-026, 146 Pages, 2010/08
The Mizunami Underground Research Laboratory (MIU), one of the main facilities in Japan for research and development of the technology for high-level radioactive waste disposal, is under construction in Mizunami City. In planning the construction, it was necessary to get reliable information on the bedrock conditions, specifically the rock mass stability and hydrogeology. Therefore, borehole investigations were conducted before excavations started. The results indicated that large water inflow could be expected during the excavation around the Ventilation Shaft at GL-200m and GL-300m Access/Research Gallery. In order to reduce water inflow, pre-excavation grouting was conducted before excavation of shafts and research tunnels. Grouting is the injection of material such as cement into a rock mass to stabilize and seal the rock. This report describes the knowledge and lessons learned during the planning and conducting of pre-excavation grouting.
Kuji, Masayoshi*; Matsui, Hiroya; Hara, Masato; Minamide, Masashi*; Mikake, Shinichiro; Takeuchi, Shinji; Sato, Toshinori*; Asai, Hideaki
JAEA-Research 2008-095, 54 Pages, 2009/01
A large amount of water inflow is frequently generated during the excavation of an underground cavern, such as road and railway tunnels, underground electric facilities etc. The reduction of water inflow is sometimes quite important for the reduction of cost for the water treatment and pumping during the construction of an underground cavern. The Mizunami Underground Research Laboratory (MIU) is currently being constructed by Japan Atomic Energy Agency. During its excavation, a large amount of water inflow into the shafts has been increasing and affecting the project progress. Therefore, a field experiment of post-excavation grouting around the Ventilation Shaft in a sedimentary formation carried out to confirm the effect of existing grouting technology for sedimentary formations in MIU project. The result shows that the applied methods in this field experiment are effective to prevent water inflow. This report describes the summary of the field experiment and the knowledge obtained through the experiment.
Kuji, Masayoshi*; Asai, Hideaki; Mikake, Shinichiro; Hara, Masato
Maeda Kensetsu Gijutsu Kenkyushoho (CD-ROM), 8 Pages, 2008/09
The Mizunami Underground Research Laboratory is currently being constructed by Japan Atomic Energy Agency. During its excavation, large amount of water inflow into the shafts has been increasing and affecting the project progress. As countermeasures for reducing water inflow, grouting methods are being considered, one is post-excavation grouting for the area already excavated, and another is pre-excavation grouting for the area excavate in future. Therefore, the field experiment for post-excavation grouting was carried out, and the result show that the applied methods in this field experiment is effective to prevent the draining. And pre-excavation grouting has been undertaken and the applicability of several techniques has been evaluated. This report describes the summary of the Mizunami Underground Research Laboratory and field experiments of post- and pre-excavation grouting method.
Matsui, Hiroya; Mikake, Shinichiro; Asai, Hideaki; Sugihara, Kozo
no journal, ,
In the construction phase of the MIU project, engineering studies have focused on research into design and construction technologies for deep underground. The main subjects consist of the following: "Demonstration of the design methodology", "Demonstration of existing and supplementary excavation methods", "Demonstration of countermeasures during excavation" and "Demonstration of safe construction". In the FY 2007, identification and evaluation of the subjects for this study were carried out to optimize future research work. Specific studies have been performed as well. Based on these studies, future research focused on the four subject areas has been identified. The design methodology in the surface-based investigation phase was verified to 200 m depth. Evaluation of countermeasures and studies of concepts for the estimation of the influence of high differential water pressures, long-term maintenance and risk management have been proposed with respect to the geological disposal project.
Asai, Hideaki; Matsui, Hiroya; Mikake, Shinichiro; Sugihara, Kozo
no journal, ,
The Mizunami Underground Research Laboratory (MIU) is currently being constructed by Japan Atomic Energy Agency. As part of MIU Project, development of engineering technology for deep underground intended for the crystalline rock is executed. The research to confirm the effectiveness of engineering technology is being executed during its excavation now. It reports on the current state of engineering technology research and the schedule for the future.
Asai, Hideaki; Matsui, Hiroya; Mikake, Shinichiro; Ito, Hiroaki; Horiuchi, Yasuharu; Ishii, Yoji
no journal, ,
The Mizunami Underground Research Laboratory (MIU) is currently being constructed by Japan Atomic Energy Agency. As part of MIU Project, development of engineering technology for deep underground intended for the crystalline rock is executed. The research to confirm the effectiveness of engineering technology is being executed during its excavation now. It reports on study results up to 300m in depth of engineering technology research and the schedule for the future.
Matsui, Hiroya; Mikake, Shinichiro; Asai, Hideaki; Ishii, Yoji; Horiuchi, Yasuharu; Kumada, Koji
no journal, ,
The Mizunami Underground Research Laboratory (MIU) of the Japan Atomic Energy Agency is a major site for geoscientific research to advance the scientific and technological basis for geological disposal of high-level radioactive waste in crystalline rock. Studies on relevant engineering technologies in the MIU consist of research on design and construction technology for very deep underground applications, and engineering technology as a basis of geological disposal. In the Second Phase of the MIU project, engineering studies have focused on research into design and construction technologies for deep underground. The main subjects in the study of very deep underground structures consist of the following: Demonstration of the design methodology, Demonstration of existing and supplementary excavation methods, Demonstration of countermeasures during excavation and Demonstration of safe construction. This poster show the main topics and results of the study until FY2009.
Yanagihara, Rikuto; Ideguchi, Eiji*; Nishio, Katsuhisa; Orlandi, R.; Makii, Hiroyuki; Asai, Masato; Hirose, Kentaro; Tsukada, Kazuaki; Toyoshima, Atsushi; Sato, Tetsuya; et al.
no journal, ,