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Journal Articles

Incommensurate helimagnetic structure of Ba(Fe$$_{1-x}$$Sc$$_{x}$$)$$_{12}$$O$$_{19}$$ determined by single-crystal neutron diffraction

Tanaka, Seiya*; Kiyanagi, Ryoji; Ishikawa, Yoshihisa*; Amako, Yasushi*; Iiyama, Taku*; Futamura, Ryusuke*; Maruyama, Kenichi*; Utsumi, Shigenori*

Physical Review Materials (Internet), 7(1), p.014403_1 - 014403_11, 2023/01

Journal Articles

Magnetic phase diagram of helimagnetic Ba(Fe$$_{1-x}$$Sc$$_{x}$$)$$_{12}$$O$$_{19}$$ (0 $$leq$$ x $$leq$$ 0.2) hexagonal ferrite

Maruyama, Kenichi*; Tanaka, Seiya*; Kiyanagi, Ryoji; Nakao, Akiko*; Moriyama, Kentaro*; Ishikawa, Yoshihisa*; Amako, Yasushi*; Iiyama, Taku*; Futamura, Ryusuke*; Utsumi, Shigenori*; et al.

Journal of Alloys and Compounds, 892, p.162125_1 - 162125_8, 2022/02

 Times Cited Count:2 Percentile:17.65(Chemistry, Physical)

Journal Articles

Flux growth and magnetic properties of helimagnetic hexagonal ferrite Ba(Fe$$_{1-x}$$Sc$$_{x}$$)$$_{12}$$O$$_{19}$$ single crystals

Utsumi, Shigenori*; Tanaka, Seiya*; Maruyama, Kenichi*; Amako, Yasushi*; Kiyanagi, Ryoji; Nakao, Akiko*; Moriyama, Kentaro*; Ishikawa, Yoshihisa*; 9 of others*

ACS Omega (Internet), 5(38), p.24890 - 24897, 2020/09

 Times Cited Count:4 Percentile:21.77(Chemistry, Multidisciplinary)

Fabricating large, high-crystalline-quality single-crystal samples of hexagonal ferrite Ba(Fe$$_{1-x}$$Sc$$_{x}$$)$$_{12}$$O$$_{19}$$ is the first important step to elucidating its helimagnetic structure and developing it for further applications. In this study, single crystals of Ba(Fe$$_{1-x}$$Sc$$_{x}$$)$$_{12}$$O$$_{19}$$ of various Sc concentrations $$x$$ were successfully grown by the spontaneous crystallization method using Na$$_{2}$$O-Fe$$_{2}$$O$$_{3}$$ flux. X-ray diffraction and elemental analysis revealed that the obtained crystals were composed of single-phase Ba(Fe$$_{1-x}$$Sc$$_{x}$$)$$_{12}$$O$$_{19}$$ of high crystalline quality. The temperature dependence of magnetization and the magnetization curves at 77 K of the $$x$$ = 0.128 crystal exhibited behavior characteristics of helimagnetism. Neutron diffraction measurements of the $$x$$ = 0.128 crystal exhibited magnetic satellite reflection peaks below 211K, proving evidence that Ba(Fe$$_{1-x}$$Sc$$_{x}$$)$$_{12}$$O$$_{19}$$ behaves as a helimagnetic material.

Journal Articles

Impact hammer test of ITER blanket remote handling system

Noguchi, Yuto; Maruyama, Takahito; Ueno, Kenichi; Komai, Masafumi; Takeda, Nobukazu; Kakudate, Satoshi

Fusion Engineering and Design, 109-111(Part B), p.1291 - 1295, 2016/11

 Times Cited Count:2 Percentile:19.85(Nuclear Science & Technology)

This paper reports the impact hammer test of the full-scale mock-up of ITER Blanket Remote Handling system (BRHS). Since the BRHS, which is composed of the articulated rail and the vehicle manipulator which travels on the rail deployed in the vacuum vessel, is subjected to the floor response spectrum with 14 G peak at 8 Hz, evaluation of dynamic response of the system is of essential importance. Recently impact hammer testing on the full-scale mock-up of the BRHS was carried out to verify the finite element method seismic analysis and to experimentally obtain the damping ratio of the system. The results showed that the mock-up has a vertical major natural mode with a natural frequency of 7.5 Hz and a damping ratio of 0.5%. While higher structural damping ratios is predicted in a high amplitude excitation such as major earthquake, it was confirmed that the experimental natural major frequencies are in agreement with the major frequencies obtained by elastic dynamic analysis.

Journal Articles

Preliminary assessment for dust contamination of ITER in-vessel transporter

Saito, Makiko; Ueno, Kenichi; Maruyama, Takahito; Murakami, Shin; Takeda, Nobukazu; Kakudate, Satoshi; Nakahira, Masataka*; Tesini, A.*

Fusion Engineering and Design, 89(9-10), p.2352 - 2356, 2014/10

 Times Cited Count:8 Percentile:53.55(Nuclear Science & Technology)

After plasma operation of the ITER reactor, irradiated radioactive dust will accumulate in the vacuum vessel (VV). The In Vessel Transporter (IVT) will be installed in the VV and remove the blanket modules for maintenance. The IVT will be carried back to the Hot Cell Facilities (HCF) after exchanging the blanket, and the IVT itself also needs maintenance. It is considered that the maintenance workers will be exposed to the irradiated radioactive dust attached to the IVT surface. In this study, dust contamination of the IVT is evaluated to assess exposure during maintenance work in the HCF. The IVT contamination scenario is assumed in the ITER project. From plasma shut down until maintenance is performed on the IVT will take 345 days under the ITER project assumption. Under this scenario, the effective dose rate from irradiated radioactive dust was calculated as an infinite plate for each nuclide. As a result, W-181 and Ta-182 were the dominant nuclides for the effective dose rate. If all dust is W-181 or Ta-182, the effective dose rate is about 400 $$mu$$Sv/h and 100 $$mu$$Sv/h respectively. Nevertheless, using the dose limit determined by the ITER project and the estimated maximum maintenance time, the effective dose rate limit was calculated to be 4.18 $$mu$$Sv/h under these limited conditions. To satisfy the dose rate limit, decontamination processes were assumed and the dose rate after decontamination was evaluated.

Journal Articles

Dust removal experiments for ITER blanket remote handling system

Ueno, Kenichi; Aburadani, Atsushi; Saito, Makiko; Maruyama, Takahito; Takeda, Nobukazu; Murakami, Shin; Kakudate, Satoshi

Plasma and Fusion Research (Internet), 9, p.1405012_1 - 1405012_4, 2014/02

Journal Articles

Current status of a new polarized neutron reflectometer at the intense pulsed neutron source of the Materials and Life Science Experimental Facility (MLF) of J-PARC

Takeda, Masayasu; Yamazaki, Dai; Soyama, Kazuhiko; Maruyama, Ryuji; Hayashida, Hirotoshi; Asaoka, Hidehito; Yamazaki, Tatsuya; Kubota, Masato; Aizawa, Kazuya; Arai, Masatoshi; et al.

Chinese Journal of Physics, 50(2), p.161 - 170, 2012/04

Journal Articles

AMATERAS; A Cold-neutron disk chopper spectrometer

Nakajima, Kenji; Kawamura, Seiko; Kikuchi, Tatsuya; Nakamura, Mitsutaka; Kajimoto, Ryoichi; Inamura, Yasuhiro; Takahashi, Nobuaki; Aizawa, Kazuya; Suzuya, Kentaro; Shibata, Kaoru; et al.

Journal of the Physical Society of Japan, 80(Suppl.B), p.SB028_1 - SB028_6, 2011/05

 Times Cited Count:114 Percentile:95.58(Physics, Multidisciplinary)

AMATERAS is a cold-neutron disk-chopper spectrometer in MLF, J-PARC. The construction of main part of the spectrometer has been completed in spring of 2009. Soon after that, we have started the commissioning work on AMATERAS. The performance of AMATERAS has been examined by test experiments in the course of commissioning. In parallel to these works, we have started the user program on AMATERAS from December 2009 and we are getting scientific results from our spectrometer. In this presentation, we will report the current status of AMATERAS including the results of performance tests and some of examples of scientific outputs.

JAEA Reports

Modeling of failure phenomena in rocks induced by stress concentration(Phase 2)

Toriihara, Makoto*; Maruyama, Makoto*; Suzuki, Kenichiro*; Namiki, Kazuto*

JNC TJ7400 2005-034, 179 Pages, 2004/02

JNC-TJ7400-2005-034.PDF:31.02MB

Elucidation of the physichal process leading to brittle failure in crystalline rocks and modeling its mechanism is of fundamental importance in evaluating the mechanical and hydraulic properties of EDZ. In this study, Granitic rock columns and plates with circular opening were subjected to triaxial compression and tension tests and measured elastic wave velocity and resisitivity to analyze nucleation and growth of microcracks. The following conclusions were important to note that: (1)During 90% to 100% stress levels to failure stress, it appear that cracks grew on their size but no cracks were nucleated. (2)It was demonstrated that crack tensor F$$_{ij}$$ was closely related the second rank tensor V$$_{ij}$$ which was determined by measuring elastic wave velocity on at least six direction. (3)The applicability of numerical analysis model based on the micromechanics was introduced. This could be considered the mechanism of the damage growth (microcrack growth) and the interaction among microcracks. (4)On the experiment of Granitic rock plates with circular opening, the process leading to brittle failure and damage growth of the rock around the opening were observed with AE monitoring and so on. (5)In order to evaluate the variety of permeability with the damage growth, it was showed that permeability tensor in terms of crack tensor gave the permeability change in stress history.

JAEA Reports

Modeling of failure phenomena in rocks induced by stress concentration (Phase 2)

Toriihara, Makoto*; Maruyama, Makoto*; Kuwahara, T.*; Suzuki, Kenichiro*

JNC TJ7400 2005-032, 206 Pages, 2003/02

JNC-TJ7400-2005-032.PDF:29.17MB

Elucidation of the physical process leading to brittle failure in crystalline rocks and modeling its mechanism is of fundamental importance in evaluating the mechanical and hydraulic properties of EDZ. In this study, Granitic rock columns and plates with circular opening were subjected to triaxial compression and tension tests and measured elastic wave velocity and resisitivity to analyze nucleation and growth of microcracks. The following conclusions were important to note that: (1)During 90% to 100% stress levels to failure stress, it appear that cracks grew on their size but no cracks were nucleated. (2)It was demonstrated that crack tensor F$$_{ij}$$ was closely related the second rank tensor V$$_{ij}$$ which was determined by measuring elastic wave velocity on at least six direction. (3)The applicability of numerical analysis model based on the micromechanics was introduced. This could be considered the mechanism of the damage growth (microcrack growth) and the interaction among microcracks. (4)On the experiment of Granitic rock plates with circular opening, the process leading to brittle failure and damage growth of the rock around the opening were observed with AE monitoring and so on. (5)In order to evaluate the variety of permeability with the damage growth, it was showed that permeability tensor in terms of crack tensor gave the permeability change in stress history.

Journal Articles

MCD study on materials without magnetic order

Miyahara, Tsuneaki*; Ishii, Hiroyoshi*; Takayama, Yasuhiro*; Hirose, Masaaki*; Maruyama, Kenichi*; Obu, Kenji*; Shinoda, Motoki*; Muro, Takayuki*; Saito, Yuji; Matsuda, Tatsuma*; et al.

Journal of the Physical Society of Japan, 70(10), p.2977 - 2981, 2001/10

 Times Cited Count:6 Percentile:42.15(Physics, Multidisciplinary)

no abstracts in English

Oral presentation

A New polarized neutron reflectometer at materials and life science facility of J-PARC

Takeda, Masayasu; Maruyama, Ryuji; Aizawa, Kazuya; Arai, Masatoshi; Kaneko, Koji; Nakatani, Takeshi; Shinohara, Takenao; Suzuki, Junichi; Suzuya, Kentaro; Takahashi, Nobuaki; et al.

no journal, , 

Oral presentation

Polarized neutron reflectometer at J-PARC, 3

Takeda, Masayasu; Yamazaki, Dai; Maruyama, Ryuji; Hayashida, Hirotoshi; Soyama, Kazuhiko; Yamazaki, Tatsuya; Hirano, Tatsumi*; Oikawa, Kenichi; Tamura, Itaru; Sakasai, Kaoru; et al.

no journal, , 

no abstracts in English

Oral presentation

A New polarized neutron reflectometer installed at the intense pulsed neutron source of Materials and Life Science Experimental Facility (MLF) of J-PARC opening to International users

Takeda, Masayasu; Yamazaki, Dai; Soyama, Kazuhiko; Maruyama, Ryuji; Hayashida, Hirotoshi; Asaoka, Hidehito; Yamazaki, Tatsuya; Kubota, Masato; Aizawa, Kazuya; Inamura, Yasuhiro; et al.

no journal, , 

Oral presentation

Current status of the new polarized neutron reflectometer (SHARAKU) at J-PARC, and prospects for study on multilayers

Kubota, Masato; Takeda, Masayasu; Yamazaki, Dai; Hayashida, Hirotoshi; Maruyama, Ryuji; Soyama, Kazuhiko; Asaoka, Hidehito; Yamazaki, Tatsuya; Sakasai, Kaoru; To, Kentaro; et al.

no journal, , 

no abstracts in English

Oral presentation

Present status of a new polarized neutron reflectometer SHARAKU (BL17) at J-PARC MLF

Takeda, Masayasu; Yamazaki, Dai; Hayashida, Hirotoshi; Maruyama, Ryuji; Soyama, Kazuhiko; Kubota, Masato; Asaoka, Hidehito; Yamazaki, Tatsuya; Sakasai, Kaoru; To, Kentaro; et al.

no journal, , 

no abstracts in English

Oral presentation

A New polarized neutron reflectometer (SHARAKU) at the intense pulsed neutron source of the Materials and Life Science Experimental Facility of J-PARC

Takeda, Masayasu; Yamazaki, Dai; Soyama, Kazuhiko; Maruyama, Ryuji; Hayashida, Hirotoshi; Asaoka, Hidehito; Yamazaki, Tatsuya; Kubota, Masato; Aizawa, Kazuya; Arai, Masatoshi; et al.

no journal, , 

Oral presentation

Development of a new polarized neutron reflectometer at MLF in J-PARC, 4

Takeda, Masayasu; Yamazaki, Dai; Hayashida, Hirotoshi; Kubota, Masato; Maruyama, Ryuji; Soyama, Kazuhiko; Asaoka, Hidehito; Yamazaki, Tatsuya; Yoshida, Noboru*; Sakaguchi, Yoshifumi*; et al.

no journal, , 

no abstracts in English

Oral presentation

The Current status of the polarized neutron reflectometer SHARAKU

Takeda, Masayasu; Yamazaki, Dai; Hayashida, Hirotoshi; Kubota, Masato; Maruyama, Ryuji; Soyama, Kazuhiko; Asaoka, Hidehito; Yamazaki, Tatsuya; Yoshida, Noboru*; Sakaguchi, Yoshifumi*; et al.

no journal, , 

no abstracts in English

Oral presentation

Current status and perspective of the polarized neutron reflectometer, SHARAKU

Takeda, Masayasu; Yamazaki, Dai; Hayashida, Hirotoshi; Kubota, Masato; Maruyama, Ryuji; Soyama, Kazuhiko; Asaoka, Hidehito; Yamazaki, Tatsuya; Yoshida, Noboru*; Sakaguchi, Yoshifumi*; et al.

no journal, , 

no abstracts in English

29 (Records 1-20 displayed on this page)