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Journal Articles

Excitation spectra and wave functions of quasiparticle bound states in bilayer Rashba superconductors

Higashi, Yoichi*; Nagai, Yuki; Yoshida, Tomohiro*; Kato, Masaru*; Yanase, Yoichi*

Physica C, 518, p.1 - 4, 2015/11

 Times Cited Count:0 Percentile:100(Physics, Applied)

We study the excitation spectra and the wave functions of quasiparticle bound states at a vortex and an edge in bilayer Rashba superconductors under a magnetic field. In particular, we focus on the quasiparticle states at the zero energy in the pair- density wave state in a topologically non-trivial phase. We numerically demonstrate that the quasiparticle wave functions with zero energy are localized at both the edge and the vortex core if the magnetic field exceed the critical value.

Journal Articles

Thickness-dependent magnetic properties and strain-induced orbital magnetic moment in SrRuO$$_{3}$$ thin films

Ishigami, Keisuke*; Yoshimatsu, Kohei*; Toyota, Daisuke*; Takizawa, Masaru*; Yoshida, Teppei*; Shibata, Goro*; Harano, Takayuki*; Takahashi, Yukio*; Kadono, Toshiharu*; Verma, V. K.*; et al.

Physical Review B, 92(6), p.064402_1 - 064402_5, 2015/08

 Times Cited Count:20 Percentile:23.25(Materials Science, Multidisciplinary)

JAEA Reports

Annual report of Nuclear Emergency Assistance and Training Center (April 1, 2013 - March 31, 2014)

Sato, Takeshi; Muto, Shigeo; Akiyama, Kiyomitsu; Aoki, Kazufumi; Okamoto, Akiko; Kawakami, Takeshi; Kume, Nobuhide; Nakanishi, Chika; Koie, Masahiro; Kawamata, Hiroyuki; et al.

JAEA-Review 2014-048, 69 Pages, 2015/02

JAEA-Review-2014-048.pdf:13.91MB

JAEA was assigned as a designated public institution under the Disaster Countermeasures Basic Act and under the Armed Attack Situations Response Act. Based on these Acts, the JAEA has the responsibility of providing technical support to the national government and/or local governments in case of disaster responses or response in the event of a military attack, etc. In order to fulfill the tasks, the JAEA has established the Emergency Action Plan and the Civil Protection Action Plan. In case of a nuclear emergency, NEAT dispatches specialists of JAEA, supplies the national government and local governments with emergency equipment and materials, and gives technical advice and information. In normal time, NEAT provides various exercises and training courses concerning nuclear disaster prevention to those personnel taking an active part in emergency response institutions of the national and local governments, police, fire fighters, self-defense forces, etc. in addition to the JAEA itself. The NEAT also researches nuclear disaster preparedness and response, and cooperates with international organizations. In the FY2013, the NEAT accomplished the following tasks: (1) Technical support activities as a designated public institution in cooperation with the national and local governments, etc. (2) Human resource development, exercise and training of nuclear emergency response personnel for the national and local governments, etc. (3) Researches on nuclear disaster preparedness and response, and sending useful information (4) International contributions to Asian countries on nuclear disaster preparedness and response in collaboration with the international organizations

JAEA Reports

Conceptual design of the SlimCS fusion DEMO reactor

Tobita, Kenji; Nishio, Satoshi*; Enoeda, Mikio; Nakamura, Hirofumi; Hayashi, Takumi; Asakura, Nobuyuki; Uto, Hiroyasu; Tanigawa, Hiroyasu; Nishitani, Takeo; Isono, Takaaki; et al.

JAEA-Research 2010-019, 194 Pages, 2010/08

JAEA-Research-2010-019-01.pdf:48.47MB
JAEA-Research-2010-019-02.pdf:19.4MB

This report describes the results of the conceptual design study of the SlimCS fusion DEMO reactor aiming at demonstrating fusion power production in a plant scale and allowing to assess the economic prospects of a fusion power plant. The design study has focused on a compact and low aspect ratio tokamak reactor concept with a reduced-sized central solenoid, which is novel compared with previous tokamak reactor concept such as SSTR (Steady State Tokamak Reactor). The reactor has the main parameters of a major radius of 5.5 m, aspect ratio of 2.6, elongation of 2.0, normalized beta of 4.3, fusion out put of 2.95 GW and average neutron wall load of 3 MW/m$$^{2}$$. This report covers various aspects of design study including systemic design, physics design, torus configuration, blanket, superconducting magnet, maintenance and building, which were carried out increase the engineering feasibility of the concept.

Journal Articles

Quantum beam technology; Nanostructured proton-conductive membranes prepared by swift heavy ion irradiation for fuel cell applications

Yamaki, Tetsuya; Kobayashi, Misaki*; Asano, Masaharu; Nomura, Kumiko*; Takagi, Shigeharu*; Maekawa, Yasunari; Yoshida, Masaru*

Proceedings of Sadoway 60 Symposium, p.114 - 120, 2010/06

My presentation deals with the application of high-energy heavy ion beams from the cyclotron accelerator of Takasaki Ion Accelerators for Advanced Radiation Application (TIARA), JAEA. Our strategic focus is centered on using nano-scale controllability of the ion-beam processing; the membrane preparation involves (1) the irradiation of commercially-available base polymer films with hundreds of MeV ions, (2) graft polymerization of vinyl monomers into electronically-excited parts along the ion trajectory, called latent tracks, and (3) sulfonation of the graft polymers. Interestingly, the resulting membranes exhibited anisotropic proton transport, i.e., higher conductivity in the thickness direction. According to microscopic observations, this is probably because the columnar electrolyte phase extended, with a width of tens-to-hundreds nanometers, through the membrane.

Journal Articles

29th report of ITPA topical group meeting

Isayama, Akihiko; Sakakibara, Satoru*; Furukawa, Masaru*; Matsunaga, Go; Yamazaki, Kozo*; Watanabe, Kiyomasa*; Idomura, Yasuhiro; Sakamoto, Yoshiteru; Tanaka, Kenji*; Tamura, Naoki*; et al.

Purazuma, Kaku Yugo Gakkai-Shi, 86(6), p.374 - 377, 2010/06

no abstracts in English

Journal Articles

Recent progress in the energy recovery linac project in Japan

Sakanaka, Shogo*; Akemoto, Mitsuo*; Aoto, Tomohiro*; Arakawa, Dai*; Asaoka, Seiji*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; et al.

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2338 - 2340, 2010/05

Future synchrotron light source using a 5-GeV energy recovery linac (ERL) is under proposal by our Japanese collaboration team, and we are conducting R&D efforts for that. We are developing high-brightness DC photocathode guns, two types of cryomodules for both injector and main superconducting (SC) linacs, and 1.3 GHz high CW-power RF sources. We are also constructing the Compact ERL (cERL) for demonstrating the recirculation of low-emittance, high-current beams using above-mentioned critical technologies.

Journal Articles

27th report of ITPA topical group meeting

Osakabe, Masaki*; Shinohara, Koji; Toi, Kazuo*; Todo, Yasushi*; Hamamatsu, Kiyotaka; Murakami, Sadayoshi*; Yamamoto, Satoshi*; Idomura, Yasuhiro; Sakamoto, Yoshiteru; Tanaka, Kenji*; et al.

Purazuma, Kaku Yugo Gakkai-Shi, 85(12), p.839 - 842, 2009/12

no abstracts in English

Journal Articles

Preparation of PTFE-based fuel cell membranes by combining latent track formation technology with graft polymerization

Yoshida, Masaru*; Kimura, Yosuke*; Chen, J.; Asano, Masaharu; Maekawa, Yasunari

Radiation Physics and Chemistry, 78(12), p.1060 - 1066, 2009/12

 Times Cited Count:13 Percentile:29.35(Chemistry, Physical)

The swift heavy ions of 56 MeV $$^{15}$$N$$^{3+}$$were irradiated with particle fluences of 3 $$times$$ 10$$^{7}$$ ions/cm$$^{2}$$ to form the latent track zone for a 25 $$mu$$m-thick film of polytetrafluoroethylene (iPTFE). The styrene (St) was grafted onto the iPTFE films by UV-irradiation and pre-$$gamma$$-irradiation and the resulting iPTFE-based proton conducting membranes were obtained after sulfonation, namely, iPTFE-g(UV)-PStSA and iPTFE-g($$gamma$$)-PStSA membranes, which have a straight cylindrical damage zone around the ion path. The degree of grafting was obtained to be about 7.5% in both the UV-method and the $$gamma$$-method. The ion exchange capacity, proton conductivity in thickness direction, MeOH permeability, tensile strength and elongation at break of the obtained iPTFE-g(UV)-PStSA membrane were 0.50 mmol/g, 0.06 S/cm, 0.15 $$times$$ 10$$^{-6}$$ cm$$^{2}$$/s, 50 MPa and 600%, in contrast to 0.06 mmol/g, 0.06 S/cm, 0.35 $$times$$ 10$$^{-6}$$ cm$$^{2}$$/s, 19 MPa and 210% for the iPTFE-g($$gamma$$)-PStSA membrane, respectively. For comparison, the Nafion 112 measured in our laboratory showed an ion exchange capacity of 0.91 mmol/g, a proton conductivity of 0.06 S/cm, a MeOH permeability of 1.02 $$times$$ 10$$^{-6}$$ cm$$^{2}$$/s, a tensile strength of 35 MPa and an elongation at break of 295%. It could conclude from these data that the lower crossover of MeOH, proton conductibility of the Nafion corresponding even in lower ion exchange capacity and higher mechanical properties of the UV-grafted proton-conducting membranes make them promising materials for widespread application in direct methanol fuel cell.

Journal Articles

Fuel-cell performance of multiply-crosslinked polymer electrolyte membranes prepared by two-step radiation technique

Yamaki, Tetsuya; Sawada, Shinichi; Asano, Masaharu; Maekawa, Yasunari; Yoshida, Masaru*; Gubler, L.*; Alkan G$"u$rsel, S.*; Scherer, G. G.*

ECS Transactions, 25(1), p.1439 - 1450, 2009/10

 Times Cited Count:4 Percentile:13.41

A multiply-crosslinked polymer electrolyte membrane was prepared by the radiation-induced co-grafting of styrene and a bis(vinyl phenyl)ethane (BVPE) crosslinker into a radiation-crosslinked polytetrafluoroethylene (cPTFE) film. We then investigated its hydrogen/oxygen fuel-cell performance at 60 and 80$$^{circ}$$C in terms of the effect of radiation and chemical crosslinking. At 60$$^{circ}$$C, all the membranes initially exhibited similar performance, but only the cPTFE-based membranes were durable at 80$$^{circ}$$C, indicating the necessity of radiation crosslinking in the PTFE main chains. Importantly, cell performance of the multiply-crosslinked membrane was found high enough to reach that of a Nafion112 membrane. This is probably because the BVPE crosslinks in the graft component improved the membrane-electrode interface in addition to membrane durability. After severe OCV hold tests at 80 and 95$$^{circ}$$C, the performance deteriorated, while no significant change was observed in ohmic resistivity. Accordingly, our membranes seemed so chemically stable that an influence on overall performance loss could be negligible.

Journal Articles

Immobilization of functional materials onto poly(styrene-$$co$$-divinylbenzene) gels by $$gamma$$ irradiation and adsorption properties

Mishima, Satoko*; Asano, Masaharu; Yoshida, Masaru

Kobunshi Rombunshu, 66(7), p.250 - 258, 2009/07

 Times Cited Count:1 Percentile:95.08(Polymer Science)

Pectin and triallylisocyanurate (TAIC) were immobilized onto poly(styrene-$$co$$-divinylbenzene) (PSD) beads by irradiating in the range of 2.5 to 25 kGy using $$gamma$$-rays from a $$^{60}$$Co source. The adsorption performance of methyl-2-benzimidazolylcarbamate (MBC) treated with immobilized Pectin- TAIC beads was investigated. Pectin was effective to enhance the MBC uptakes at pH11, in contrast to pH3 for TAIC. The amounts of MBC uptake of immobilized Pectin-TAIC beads were 1.3$$sim$$3.9 times higher than those of PSD beads which were only irradiated without the use of Pectin and TAIC in the range of pH3 to pH11. The cycles of absorption-desorption assays show that the sorption performance of immobilized Pectin-TAIC beads shows excellent reproducibility, suggesting that the immobilized Pectin-TAIC beads are a useful adsorbent for the extraction of MBC from environmental water.

Journal Articles

Compact DEMO, SlimCS; Design progress and issues

Tobita, Kenji; Nishio, Satoshi; Enoeda, Mikio; Kawashima, Hisato; Kurita, Genichi; Tanigawa, Hiroyasu; Nakamura, Hirofumi; Honda, Mitsuru; Saito, Ai*; Sato, Satoshi; et al.

Nuclear Fusion, 49(7), p.075029_1 - 075029_10, 2009/07

 Times Cited Count:117 Percentile:1.66(Physics, Fluids & Plasmas)

Recent design study on SlimCS focused mainly on the torus configuration including blanket, divertor, materials and maintenance scheme. For vertical stability of elongated plasma and high beta access, a sector-wide conducting shell is arranged in between replaceable and permanent blanket. The reactor adopts pressurized-water-cooled solid breeding blanket. Compared with the previous advanced concept with supercritical water, the design options satisfying tritium self-sufficiency are relatively scarce. Considered divertor technology and materials, an allowable heat load to the divertor plate should be 8 MW/m$$^{2}$$ or lower, which can be a critical constraint for determining a handling power of DEMO (a combination of alpha heating power and external input power for current drive).

Journal Articles

Thermo- and pH-responsive poly(A-ProOMe)-${it graft}$-poly (AAc) membrane for selective separation of metal ions

Hasegawa, Shin; Ohashi, Hitoshi; Maekawa, Yasunari; Katakai, Ryoichi*; Yoshida, Masaru

Polymer Journal, 41(7), p.533 - 540, 2009/07

 Times Cited Count:3 Percentile:86.25(Polymer Science)

We investigated the permeation behavior of Li over Co and Ni ions through thermo- and pH-responsive gel membranes. The gel membranes were synthesized by $$gamma$$-ray grafting of pH-responsive poly (acrylic acid) (AAc) onto a thermo-responsive polymer gel of acryloyl-L-proline methyl ester (A-ProOMe). The permeation constant of Li ions is 3.5 and 2.8 times higher than those of Co and Ni ions at 30 $$^{circ}$$C in a pH 6.0. The most appropriate temperature and pH through the 15% grafted membrane were 30 $$^{circ}$$C and pH 6.0. The adjacencies of the carboxyl groups of poly (AAc) surrounded by thermo-responsive poly (A-ProOMe) matrix must be decisive for the selective Li ion permeability. From the microscopic structures using SEM and the distributions of Co and Ni ions by EDS analysis, we confirmed that the structures formed by the flexible grafted chains of the carboxyl groups onto the thermo-response gel membrane are significant for the selective permeation of Li ion.

JAEA Reports

Mizunami Underground Research Laboratory Project annual report for fiscal year 2006

Nishio, Kazuhisa; Matsuoka, Toshiyuki; Mikake, Shinichiro; Tsuruta, Tadahiko; Amano, Kenji; Oyama, Takuya; Takeuchi, Ryuji; Saegusa, Hiromitsu; Hama, Katsuhiro; Yoshida, Haruo*; et al.

JAEA-Review 2009-001, 110 Pages, 2009/03

JAEA-Review-2009-001.pdf:49.84MB

Japan Atomic Energy Agency (JAEA) at Tono Geoscience Center (TGC) is developing a geoscientific research project named Mizunami Underground Research Laboratory (MIU) project in crystalline rock environment in order to establish scientific and technological basis for geological disposal of HLW. Geoscientific research at MIU is planned to be carried out in three phases over a period of 20 years; Surface-based Investigation Phase (Phase 1), Construction Phase (Phase 2) and Operation Phase (Phase 3). Currently, the project is under the Construction Phase. This document presents the following results of the research and development performed in 2006 fiscal year, as a part of the Construction Phase based on the MIU Master Plan updated in 2002, (1) Investigation at the MIU Construction Site, (2) Construction at the MIU Construction Site, (3) Research Collaboration.

JAEA Reports

Mizunami Underground Research Laboratory Project annual report for fiscal year 2005

Nishio, Kazuhisa; Matsuoka, Toshiyuki; Mikake, Shinichiro; Tsuruta, Tadahiko; Amano, Kenji; Oyama, Takuya; Takeuchi, Ryuji; Saegusa, Hiromitsu; Hama, Katsuhiro; Yoshida, Haruo*; et al.

JAEA-Review 2008-073, 99 Pages, 2009/03

JAEA-Review-2008-073-1.pdf:37.33MB
JAEA-Review-2008-073-2.pdf:37.16MB

Japan Atomic Energy Agency (JAEA) at Tono Geoscience Center (TGC) is developing a geoscientific research project named Mizunami Underground Research Laboratory (MIU) project in crystalline rock environment in order to establish scientific and technological basis for geological disposal of HLW. Geoscientific research at MIU is planned to be carried out in three phases over a period of 20 years; Surface-based Investigation Phase (Phase 1), Construction Phase (Phase 2) and Operation Phase (Phase 3). Currently, the project is under the Construction Phase. This document presents the following results of the research and development performed in 2005 fiscal year, as a part of the Construction Phase based on the MIU Master Plan updated in 2002, (1) Investigation at the MIU Construction Site, (2) Construction at the MIU Construction Site, (3) Research Collaboration.

Journal Articles

Topological transition from accretion to ejection in a disk-jet system; Singular perturbation of the Hall effect in a weakly ionized plasma

Shiraishi, Junya; Yoshida, Zensho*; Furukawa, Masaru*

Astrophysical Journal, 697(1), p.100 - 105, 2009/03

 Times Cited Count:4 Percentile:82.96(Astronomy & Astrophysics)

A thin disk accompanied by spindle-like jet, created commonly near massive central objects, exhibits a topologically singular aspect when viewed from an ideal macroscopic theory. The accreting inflow and jet's outflow are "singular perturbation" on the ambient Keplerian rotation, which are generated by some non-ideal higher-order (in the order of derivatives) effect. The Hall effect can generate such a structure in a weakly ionized plasma of a protostellar disk. Numerical estimate of the characteristic length scale defined by the singular perturbation justifies the precedence of the Hall effect.

Journal Articles

Hydrocarbon proton-conductive membranes prepared by radiation-grafting of styrenesulfonate onto aromatic polyamide films

Li, D.*; Chen, J.; Zhai, M.; Asano, Masaharu; Maekawa, Yasunari; Oku, Hiroyuki*; Yoshida, Masaru

Nuclear Instruments and Methods in Physics Research B, 267(1), p.103 - 107, 2009/01

 Times Cited Count:27 Percentile:10.56(Instruments & Instrumentation)

Novel method for preparing aromatic hydrocarbon proton-conductive membranes without sulfonation and membrane casting process is achieved by radiation grafting of sodium styrenesulfonate to an aromatic polyamide, poly(m-xylylene adipamide) (Nylon-MXD6) films and subsequent ion-exchange. The styrenesulfonate was easily grafted into the Nylon-MXD6 films from an oxygen-free dimethyl sulfoxide (DMSO) solution. As a result, the resulted styrenesulfonic acid-grafted Nylon-MXD6 films, namely proton-conductive membrane, with high ion exchange capacity up to 1.63 mmol/g, can be obtained. The membrane was transparent and highly hydrophilic. Furthermore, the methanol permeability was significantly lower than that of the Nafion membrane. Therefore, the Nylon-MXD6-based proton-conductive membrane is a more promising material for the direct methanol fuel cells (DMFCs).

Journal Articles

Report on ITPA meetings, 24

Idomura, Yasuhiro; Yoshida, Maiko; Yagi, Masatoshi*; Tanaka, Kenji*; Hayashi, Nobuhiko; Sakamoto, Yoshiteru; Tamura, Naoki*; Oyama, Naoyuki; Urano, Hajime; Aiba, Nobuyuki; et al.

Purazuma, Kaku Yugo Gakkai-Shi, 84(12), p.952 - 955, 2008/12

no abstracts in English

Journal Articles

Electron-beam-induced color imaging of acid-chromic polymer films

Maekawa, Yasunari; Yuasa, Kanako*; Enomoto, Kazuyuki; Matsushita, Harumi*; Kato, Jun*; Yamashita, Takashi*; Ito, Kazuo*; Yoshida, Masaru

Chemistry of Materials, 20(16), p.5320 - 5324, 2008/08

 Times Cited Count:2 Percentile:89.26(Chemistry, Physical)

Polymer films with acid-responsive chromic dyes and acid generators have been designed for an electron beam (EB)-induced color imaging system. Arylsulfonic acid esters and triphenylsulfonium salts were used as an EB-sensitive acid generator; the acid (H$$^{+}$$) allows a chromic reaction with rhodamine B base (RB) and 4,4'-bis(dimethylamino)benzhydrol (BH) to be triggered. Upon EB irradiation, poly(methyl methacrylate) (PMMA) films consisting of RB or BH and acid generators exhibited a characteristic absorption band with $$lambda$$max at 560 and at 612 nm, respectively, and an isosbestic point. These spectral changes clearly indicate that colorless chromic dyes in PMMA are transformed selectively to the colored form. The color imaging of these films was performed by electron beam direct writing (EBDW) with a 50 nm diameter beam to form 100 - 1000 nm line and space patterns and was evaluated by optical and confocal laser microscopy. EBDW on the acid chromic polymer films, especially for BH, yielded clear color imaging of 100 - 200 nm line and space patterns with a dose of only 10 $$mu$$C/cm$$^{2}$$. The confocal laser microscopy gave thinner lines than the laser wavelength (632.8 nm), probably because of the large change in refractive index of the patterned film induced by EB irradiation even with a low energy dose.

Journal Articles

Chemically stable hybrid polymer electrolyte membranes prepared by radiation grafting, sulfonation, and silane-crosslinking techniques

Chen, J.; Asano, Masaharu; Maekawa, Yasunari; Yoshida, Masaru

Journal of Polymer Science, Part A; Polymer Chemistry, 46(16), p.5559 - 5567, 2008/08

To prepare a crosslinked hybrid polymer electrolyte membrane (PEM) with high chemical stability, $$p$$-styryltrimethoxysilane (StSi) was first grafted to ETFE film by preirradiation. Hydrolysis-condensation and sulfonation were then performed on the StSi-grafted ETFE films to give them crosslinks and proton conductibility, respectively. The crosslinks enhance the chemical and thermal stability of the PEM. The effect of the timing of the hydrolysis-condensation and the sulfonation method on the properties of the resulting hybrid PEMs such as ion exchange capacity, proton conductivity, water uptake, chemical stability, and methanol permeability were investigated to confirm their applicability in fuel cells.

299 (Records 1-20 displayed on this page)