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Journal Articles

Structural phase transition in cobalt oxyfluoride Co$$_{3}$$Sb$$_{4}$$O$$_{6}$$F$$_{6}$$ observed by high-resolution synchrotron and neutron diffraction

Shimono, Seiya*; Ishibashi, Hiroki*; Nagayoshi, Yusuke*; Ikeno, Hidekazu*; Kawaguchi, Shogo*; Hagihara, Masato; Torii, Shuki*; Kamiyama, Takashi*; Ichihashi, Katsuya*; Nishihara, Sadafumi*; et al.

Journal of Physics and Chemistry of Solids, 163, p.110568_1 - 110568_7, 2022/04

Journal Articles

Optimum temperature for HIP bonding invar alloy and stainless steel

Wakui, Takashi; Ishii, Hideaki*; Naoe, Takashi; Kogawa, Hiroyuki; Haga, Katsuhiro; Wakai, Eiichi; Takada, Hiroshi; Futakawa, Masatoshi

Materials Transactions, 60(6), p.1026 - 1033, 2019/06

 Times Cited Count:1 Percentile:13.55(Materials Science, Multidisciplinary)

The mercury target has large size as 1.3$$times$$1.3$$times$$2.5 m$$^{3}$$. In view of reducing the amount of wastes, we studied the structure so that the fore part could be separated. The flange is required to have high seal performance less than 1$$times$$10$$^{-6}$$ Pa m$$^{3}$$/s. Invar with low thermal expansion is a candidate. Due to its low stiffness, however, the flange may deform when it is fastened by bolts. Practically invar is reinforced with stainless steel where all interface between them has to be bonded completely with the HIP bonding. In this study, we made specimens at four temperatures and conducted tensile tests. The specimen bonded at 973 K had little diffusion layer, and so fractured at the interface. The tensile strength reduced with increasing the temperature, and the reduced amount was about 10% at 1473 K. The analyzed residual stresses near the interface increased by 50% at maximum. Then, we concluded that the optimum temperature was 1173 K.

Journal Articles

Fine dispersion of Pt$$_{4-5}$$ subnanoclusters and Pt single atoms over porous carbon supports and their structural analyses with X-ray absorption spectroscopy

Itoi, Hiroyuki*; Nishihara, Hirotomo*; Kobayashi, Shunsuke*; Ittisanronnachai, S.*; Ishii, Takafumi*; Berenguer, R.*; Ito, Masashi*; Matsumura, Daiju; Kyotani, Takashi*

Journal of Physical Chemistry C, 121(14), p.7892 - 7902, 2017/04

 Times Cited Count:26 Percentile:78.77(Chemistry, Physical)

Journal Articles

Mechanical characteristics of rock segment for reducing amount of cement use and stability of drift tunnel

Tada, Hiroyuki*; Kumasaka, Hiroo*; Saito, Akira*; Nakaya, Atsushi*; Ishii, Takashi*; Fujita, Tomo; Sugita, Yutaka; Nakama, Shigeo; Sanada, Masanori*

Doboku Gakkai Rombunshu, F2 (Chika Kukan Kenkyu) (Internet), 73(1), p.11 - 28, 2017/03

This study examined the mechanical characteristics of rock segments and backfill materials and analyzed the stability of the drift that is supported by the rock segments and gravel backfill. The results confirmed the technical aspects of the formation of the rock segments and the effectiveness of the planned efforts to further reduce the amount of cement used.

JAEA Reports

Synthesized research report in the second mid-term research phase; Mizunami Underground Research Laboratory Project, Horonobe Underground Research Laboratory Project and Geo-stability Project

Hama, Katsuhiro; Mizuno, Takashi; Sasao, Eiji; Iwatsuki, Teruki; Saegusa, Hiromitsu; Sato, Toshinori; Fujita, Tomo; Sasamoto, Hiroshi; Matsuoka, Toshiyuki; Yokota, Hideharu; et al.

JAEA-Research 2015-007, 269 Pages, 2015/08

JAEA-Research-2015-007.pdf:68.65MB
JAEA-Research-2015-007(errata).pdf:0.07MB

We have synthesised the research results from Mizunami/Horonobe URLs and geo-stability projects in the second mid-term research phase. It could be used as technical bases for NUMO/Regulator in each decision point from sitting to beginning of disposal (Principal Investigation to Detailed Investigation Phase). High quality construction techniques and field investigation methods have been developed and implemented and these will be directly applicable to the National Disposal Program (along with general assessments of hazardous natural events and processes). It will be crucial to acquire technical knowledge on decisions of partial backfilling and final closure by actual field experiments in Mizunami/Horonobe URLs as main themes for the next phases.

JAEA Reports

A Study on the method of an equivalent continuous body modelling using crack tensor theory in the Mizunami Underground Research Laboratory Project

Sanada, Hiroyuki; Sato, Toshinori; Tanno, Takeo*; Hikima, Ryoichi*; Tada, Hiroyuki*; Kumasaka, Hiroo*; Ishii, Takashi*; Sakurai, Hideyuki*

JAEA-Research 2014-006, 124 Pages, 2014/06

JAEA-Research-2014-006.pdf:11.26MB

Japan Atomic Energy Agency has been implementing the Mizunami Underground Research Laboratory (MIU) Project in order to develop the comprehensive investigation techniques for the geological environment and the engineering techniques to construct a deep underground laboratory in crystalline rock. In the rock mechanical study in the MIU Project, the development of the evaluation method for the excavation damaged zone due to excavation of shafts and research galleries is one of the important issues. In this report, crack tensor was calculated using the tunnel wall mapping and rock mechanical test results in the shaft and research galleries in the MIU. Two dimension excavation analysis was conducted at the Ventilation Shaft and GL -500 m Sub Stage using the calculated crack tensor at GL -500 m. Based on calculated crack tensor at GL 500 m, validation of the crack tensor at GL -500 m estimated during Phase I was verified. Relative error of crack tensor was calculated in order to examine variation of relative error to the scale of observation areas.

Journal Articles

Bipartite magnetic parent phases in the iron oxypnictide superconductor

Hiraishi, Masatoshi*; Iimura, Soshi*; Kojima, Kenji*; Yamaura, Junichi*; Hiraka, Haruhiro*; Ikeda, Kazutaka*; Miao, P.*; Ishikawa, Yoshihisa*; Torii, Shuki*; Miyazaki, Masanori*; et al.

Nature Physics, 10(4), p.300 - 303, 2014/04

 Times Cited Count:94 Percentile:96.38(Physics, Multidisciplinary)

Journal Articles

Quantitative analysis of the initial transport of fixed nitrogen in nodulated soybean plants using $$^{15}$$N as a tracer

Hung, N. V. P.*; Watanabe, Shiori*; Ishikawa, Shinji*; Otake, Norikuni*; Sueyoshi, Kuni*; Sato, Takashi*; Ishii, Satomi; Fujimaki, Shu; Oyama, Takuji*

Soil Science and Plant Nutrition, 59(6), p.888 - 895, 2013/12

 Times Cited Count:4 Percentile:17.96(Plant Sciences)

Journal Articles

Development of rock segment for reduction of amount of cement use

Tada, Hiroyuki*; Kumasaka, Hiroo*; Saito, Akira*; Nakaya, Atsushi*; Ishii, Takashi*; Sanada, Masanori; Noguchi, Akira*; Kishi, Hirokazu*; Nakama, Shigeo; Fujita, Tomo

Dai-13-Kai Iwa No Rikigaku Kokunai Shimpojiumu Koen Rombunshu (CD-ROM), p.133 - 138, 2013/01

The authors have been developing methods for constructing tunnels using the minimum quantities of cement-type support materials in high-level radioactive waste disposal facilities and advancing research and development about the technical formation of rock segment using low alkaline mortar. In this study, the mechanical characteristic values concerning the rock segment and backfill materials were examined. The stability analysis of tunnel supported by the rock segment and backfilling with gravel were performed. Technical formation and effectiveness of the alternative supports planned for further reduction in cement influence was confirmed from a study result above-mentioned.

Journal Articles

Electroplating of Ni microstructures on the cross section of Cu wire using PMMA mother fabricated by proton beam writing

Tanabe, Yusuke*; Iwamoto, Takashi*; Takahashi, Junichi*; Nishikawa, Hiroyuki*; Sato, Takahiro; Ishii, Yasuyuki; Kamiya, Tomihiro

JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 129, 2013/01

Journal Articles

Tilted-foil technique for producing a spin-polarized radioactive isotope beam

Hirayama, Yoshikazu*; Mihara, Mototsugu*; Watanabe, Yutaka*; Jeong, S. C.*; Miyatake, Hiroari*; Momota, Sadao*; Hashimoto, Takashi*; Imai, Nobuaki*; Matsuta, Kensaku*; Ishiyama, Hironobu*; et al.

European Physical Journal A, 48(5), p.54_1 - 54_10, 2012/05

 Times Cited Count:2 Percentile:18.46(Physics, Nuclear)

Journal Articles

Spin-orbital short-range order on a honeycomb-based lattice

Nakatsuji, Satoru*; Kuga, Kentaro*; Kimura, Kenta*; Satake, Ryuta*; Katayama, Naoyuki*; Nishibori, Eiji*; Sawa, Hiroshi*; Ishii, Rieko*; Hagiwara, Masayuki*; Bridges, F.*; et al.

Science, 336(6081), p.559 - 563, 2012/05

 Times Cited Count:105 Percentile:95.88(Multidisciplinary Sciences)

Frustrated magnetic materials can remain disordered to the lowest temperatures. Such is the case for Ba$$_3$$CuSb$$_2$$O$$_9$$, which is magnetically anisotropic at the atomic scale but curiously isotropic on mesoscopic length and time scales. We find that the frustration on the triangular lattice is imprinted in a nanostructured honeycomb lattice of Cu$$^{2+}$$ ions that resists a coherent static Jahn-Teller distortion. The resulting two-dimensional random-bond spin-1/2 system on the honeycomb lattice has a broad spectrum of spin-dimer like excitations and low-energy spin degrees of freedom that retain.

JAEA Reports

Study on equivalent continuum modeling with crack tensor on crystalline rock

Tanno, Takeo; Sato, Toshinori; Sanada, Hiroyuki; Hikima, Ryoichi; Matsui, Hiroya; Tada, Hiroyuki*; Goke, Mitsuo*; Kumasaka, Hiroo*; Ishii, Takashi*

JAEA-Research 2012-002, 86 Pages, 2012/03

JAEA-Research-2012-002.pdf:8.48MB

The Crack tensor model which is a kind of equivalent continuum model has been studied in rock mechanical investigation in the MIU. The fractured rock mass is modeled as the elastic continuum model with the crack tensor. In this study, crack tensor based on the geological observation in the MIU project was calculated, and REV (Representative Elementary Volume) in the shafts and research galleries was studied based on the relative error of the crack tensor. The correlation between the crack density, the trace length of crack and the trace of crack tensor and the rock mass classification was also studied.

Journal Articles

Development of beam generation and irradiation technology for electrostatic accelerators

Yokoyama, Akihito; Uno, Sadanori; Chiba, Atsuya; Yamada, Keisuke; Saito, Yuichi; Ishii, Yasuyuki; Sato, Takahiro; Okubo, Takeru; Agematsu, Takashi

JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 158, 2012/01

no abstracts in English

Journal Articles

Operation of the electrostatic accelerators

Agematsu, Takashi; Uno, Sadanori; Chiba, Atsuya; Yamada, Keisuke; Yokoyama, Akihito; Saito, Yuichi; Ishii, Yasuyuki; Sato, Takahiro; Okubo, Takeru; Yokota, Wataru; et al.

JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 173, 2012/01

Three electrostatic accelerators of TIARA were operated smoothly in FY 2010, and all the planned experiments were carried out except those canceled by users or the impact of Great East Japan Earthquake on March 11, 2011. On the other hand, Saturday operation for experiments was carried out after October on the Global Nuclear-Human Resource Development Initiative. The yearly operation time of the tandem accelerator, the single-ended accelerator and the ion implanter amounted to 2116, 2367 and 1800 hours, respectively, which were similar to those of usual years. Regarding the single-ended accelerator, the generator in the high-voltage terminal failed and was replaced with new one. A switching magnet was installed for a new branch beam line of the ion implanter. As to the tandem accelerator, In ion was generated and accelerated at intensity of 500 nA.

Journal Articles

Effect of nitrate on nodulation and nitrogen fixation of soybean

Oyama, Takuji; Fujikake, Hiroyuki*; Yashima, Hiroyuki*; Tanabata, Sayuri*; Ishikawa, Shinji*; Sato, Takashi*; Nishiwaki, Toshikazu*; Otake, Norikuni*; Sueyoshi, Kuni*; Ishii, Satomi; et al.

Soybean Physiology and Biochemistry, p.333 - 364, 2011/11

no abstracts in English

Journal Articles

Status of TIARA facility

Yamada, Keisuke; Nara, Takayuki; Ishibori, Ikuo; Kurashima, Satoshi; Yoshida, Kenichi; Yuyama, Takahiro; Ishizaka, Tomohisa; Agematsu, Takashi; Uno, Sadanori; Chiba, Atsuya; et al.

Proceedings of 8th Annual Meeting of Particle Accelerator Society of Japan (Internet), 3 Pages, 2011/08

no abstracts in English

Journal Articles

Current status of electrostatic accelerators at TIARA

Uno, Sadanori; Chiba, Atsuya; Yamada, Keisuke; Yokoyama, Akihito; Agematsu, Takashi; Kitano, Toshihiko*; Takayama, Terumitsu*; Orimo, Takao*; Kanai, Shinji*; Aoki, Yuki*; et al.

Dai-24-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.125 - 128, 2011/07

The yearly operation time of three electrostatic accelerators at TIARA of Japan Atomic Energy Agency is keeping the same level since 2000, the tandem accelerator, the ion implanter and the single-ended accelerator amounted to about 2000, 1900 and 2500 hours, respectively. Three electrostatic accelerators did not have damage when the Tohoku Earthquake occurred on March 11, 2011. However, these accelerators were not able to operate during the planned power outage by Tokyo Electric Power Company (TEPCO). The tandem accelerator accelerated ion beam of In, which gave intensity of 500nA with stability. Additionally, the ion implanter generated maximum 400nA at ion beam of Gd, which was used in experiments for the users.

JAEA Reports

A Study on the technology for reducing cement-type materials used for tunnel supports at high-level radioactive waste disposal sites (Joint research)

Hayashi, Katsuhiko; Noguchi, Akira; Kishi, Hirokazu; Kabayashi, Yasushi*; Nakama, Shigeo; Fujita, Tomo; Naito, Morimasa; Tada, Hiroyuki*; Kumasaka, Hiroo*; Goke, Mitsuo*; et al.

JAEA-Research 2010-057, 101 Pages, 2011/03

JAEA-Research-2010-057.pdf:7.47MB

Cement-type materials that are used for supports or grouting at high-level radioactive waste disposal facilities leach into the groundwater and create a highly alkaline environment. Of concern in highly alkaline environments are the alteration of bentonite used as buffers or backfill materials, and of surrounding rock mass, and the increased uncertainty regarding the provision of performance of the disposal system over a long period of time. In this study, to reduce the quantity of cement-type materials that cause highly alkaline environments, technical feasibility of the support structure including the materials which considered the long-term performance of the HLW disposal system are discussed by using knowledge and technology accumulated in JAEA and Shimizu Construction. Moreover, based on the results, the problems remained in the application to the future HLW disposal institution are summarized.

Journal Articles

Pre-excavation grouting with micro-fine cement below four hundreds meter depth

Ishii, Yoji; Mikake, Shinichiro; Kamiya, Akira; Watanabe, Kazuhiko; Nobuto, Jun*; Kusano, Takashi*

Dai-40-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koen Rombunshu (CD-ROM), p.185 - 190, 2011/01

The "Mizunami Underground Research Laboratory" has been carrying out scientific research in granite to establish the technological basis for high-level radioactive waste disposal. To get reliable information on the rock mass geology and hydrogeology and on the bedrock conditions, a pilot borehole investigation was carried out before sinking the Ventilation Shaft. A region with high hydraulic head and low hydraulic conductivity was intersected by the pilot borehole at around GL-400m during these investigations. To reduce water inflow during excavation, pre-excavation grouting with micro-fine cement was done in this region before sinking the ventilation shaft. Despite the high hydraulic head and the low hydraulic conductivity, effective reduction of water-inflow was achieved.

124 (Records 1-20 displayed on this page)