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Journal Articles

Evaluation of indoor air dose rate based on Cs-137 depth distribution in surrounding artificially paved surfaces surveyed 10 years after the Fukushima Daiichi Nuclear Power Plant accident

Kobayashi, Hikaru*; Suto, Masahito*; Otsuki, Kentaro*; Yoshimura, Kazuya; Yoshida, Hiroko*

Japan Architectural Review (Internet), 6(1), p.12353_1 - 12353_12, 2023/01

Journal Articles

Magnetic orderings from spin-orbit coupled electrons on kagome lattice

Watanabe, Jin*; Araki, Yasufumi; Kobayashi, Koji*; Ozawa, Akihiro*; Nomura, Kentaro*

Journal of the Physical Society of Japan, 91(8), p.083702_1 - 083702_5, 2022/08

 Times Cited Count:0 Percentile:0(Physics, Multidisciplinary)

We investigate magnetic orderings on kagome lattice numerically from the tight-binding Hamiltonian of electrons, governed by the filling factor and spin-orbit coupling (SOC) of electrons. We find that even a simple kagome lattice model can host both ferromagnetic and noncollinear antiferromagnetic orderings depending on the electron filling, reflecting gap structures in the Dirac and flat bands characteristic to the kagome lattice. Kane-Mele- or Rashba-type SOC tends to stabilize noncollinear orderings, such a magnetic spirals and 120-degree antiferromagnetic orderings, due to the effective Dzyaloshinskii-Moriya interaction from SOC. The obtained phase structure helps qualitative understanding of magnetic orderings in various kagome-layered materials with Weyl or Dirac electrons.

Journal Articles

Development of evaluation method for photocatalytic ability by ion chromatography combined with a flow-type reactor; Application to immobilized photocatalyst materials prepared by double-layer coating method

Sugita, Tsuyoshi; Kobayashi, Kentaro*; Yamazaki, Taiki*; Isaka, Mayu*; Itabashi, Hideyuki*; Mori, Masanobu*

Journal of Photochemistry and Photobiology A; Chemistry, 400, p.112662_1 - 112662_8, 2020/09

 Times Cited Count:0 Percentile:0(Chemistry, Physical)

In this study, we developed an in-line photocatalytic performance evaluation system in which a flow reactor was connected to the ion chromatography to accurately evaluate the performance of the photocatalyst. This system was used to evaluate the photocatalyst supported by the two-layer support method on the substrate, such as glass beads. The performance of the photocatalyst was evaluated using dimethyl sulfoxide (DMSO), and it was possible to monitor the decomposition of DMSO by UV and the formation of by-products, such as methane sulfonate (MSO) and sulfate (SA). This system can be expected to be useful not only for evaluating the decomposition performance of an object using a photocatalyst but also for evaluating the byproducts.

Journal Articles

How different is the core of $$^{25}$$F from $$^{24}$$O$$_{g.s.}$$ ?

Tang, T. L.*; Uesaka, Tomohiro*; Kawase, Shoichiro; Beaumel, D.*; Dozono, Masanori*; Fujii, Toshihiko*; Fukuda, Naoki*; Fukunaga, Taku*; Galindo-Uribarri, A.*; Hwang, S. H.*; et al.

Physical Review Letters, 124(21), p.212502_1 - 212502_6, 2020/05

 Times Cited Count:13 Percentile:78.47(Physics, Multidisciplinary)

The structure of a neutron-rich $$^{25}$$F nucleus is investigated by a quasifree ($$p,2p$$) knockout reaction. The sum of spectroscopic factors of $$pi 0d_{5/2}$$ orbital is found to be 1.0 $$pm$$ 0.3. The result shows that the $$^{24}$$O core of $$^{25}$$F nucleus significantly differs from a free $$^{24}$$O nucleus, and the core consists of $$sim$$35% $$^{24}$$O$$_{rm g.s.}$$, and $$sim$$65% excited $$^{24}$$O. The result shows that the $$^{24}$$O core of $$^{25}$$F nucleus significantly differs from a free $$^{24}$$O nucleus. The result may infer that the addition of the $$0d_{5/2}$$ proton considerably changes the neutron structure in $$^{25}$$F from that in $$^{24}$$O, which could be a possible mechanism responsible for the oxygen dripline anomaly.

Journal Articles

Evaluation of photocatalytic abilities by variation of conductivity and dimethyl sulfoxide; Photocatalytically active TiO$$_{2}$$-coated wire mesh prepared via a double-layer coating method

Mori, Masanobu*; Sugita, Tsuyoshi; Fujii, Kengo*; Yamazaki, Taiki*; Isaka, Mayu*; Kobayashi, Kentaro*; Iwamoto, Shinji*; Itabashi, Hideyuki*

Analytical Sciences, 34(12), p.1449 - 1453, 2018/12

 Times Cited Count:2 Percentile:8.13(Chemistry, Analytical)

The photocatalyst coating stainless-steel wire mesh (TiO$$_{2}$$-WM) was prepared by double-layer coating method. The TiO$$_{2}$$-WM was evaluated using flow analytical system, which included the reactor and conductimetric detector (FAS-CD). The DMSO decomposition test through the FAS-CD reveal that photocatalytst was stable coating on the stainless-steel wire mesh.

Journal Articles

Enhanced aqueous adsorption and photodecomposition of anionic organic target by amino group-modified TiO$$_{2}$$ as anionic adsorptive photocatalyst

Sugita, Tsuyoshi; Kobayashi, Kenichi*; Kobayashi, Kentaro*; Yamazaki, Taiki*; Fujii, Kengo*; Itabashi, Hideyuki*; Mori, Masanobu*

Journal of Photochemistry and Photobiology A; Chemistry, 356, p.71 - 80, 2018/04

 Times Cited Count:5 Percentile:15.51(Chemistry, Physical)

Photocatalysts shows high redox property only by light irradiation. However, the reaction performance is lowered in aqueous phase due to the low contact efficiency between catalyst and targets. In this study, to enhance aqueous adsorption and photodecomposition of anionic organic target, we developed an amino functional-based spacer (3-[2-(2- aminoethylamino)ethylamino]propyl-trimethoxysilane, DETA), and used it to modify TiO$$_{2}$$. The modified catalyst with positively charged amino groups could enhance the adsorption and photodecomposition of anionic organic targets.

Journal Articles

Numerical evaluation of the light transport properties of alternative He-3 neutron detectors using ceramic scintillators

Ozu, Akira; Takase, Misao*; Haruyama, Mitsuo; Kurata, Noritaka*; Kobayashi, Nozomi*; Kureta, Masatoshi; Nakamura, Tatsuya; To, Kentaro; Sakasai, Kaoru; Suzuki, Hiroyuki; et al.

Nuclear Instruments and Methods in Physics Research A, 798, p.62 - 69, 2015/10

 Times Cited Count:2 Percentile:18.84(Instruments & Instrumentation)

The light transport properties of scintillator light inside alternative He-3 neutron detector modules using scintillator sheets have been investigated by a ray-tracing simulation code. The detector module consists of a light-reflecting tube, a thin rectangular ceramic scintillator sheet laminated on a glass plate, and two photo-multiplier tubes (PMTs) mounted at both ends of the detector tube. The light induced on the surface of the scintillator sheet via nuclear interaction between the scintillator and neutrons are detected by the two PMTs. The light output of various detector modules in which the scintillator sheets are installed with several different arrangements were examined and evaluated in comparison with experimental results. The results derived from the simulation reveal that the light transport property is strongly dependent on the arrangement of the scintillator sheet inside the tube and the shape of the tube.

Journal Articles

Neutron diffraction of ice and water in hydrogels

Sekine, Yurina; Kobayashi, Riki*; Chi, S.*; Fernandez-Baca, J. A.*; Suzuya, Kentaro; Fujisaki, Fumika*; Ikeda, Kazutaka*; Otomo, Toshiya*; Fukazawa, Tomoko*; Yamauchi, Hiroki; et al.

JPS Conference Proceedings (Internet), 8, p.033009_1 - 033009_6, 2015/09

Neutron diffraction profiles of low-D$$_{2}$$O-content poly-N,N,-dimethylacrylamide (PDMAA) hydrogels were measured from 100 to 300 K to investigate the structure and properties of water in hydrogels. A broad diffraction observed at temperatures lower than 220 K indicates the existence of amorphous ice in the hydrogels at low temperatures. During the heating process, diffraction peaks from ice crystals appear in the profiles. These peaks indicate that cubic ice and hexagonal ice exist at T $$geq$$ 220 K. We refined the structure parameters of these ices in the hydrogel, which indicate the existence of low-density ice in the hydrogel.

Journal Articles

Real-time observation of irradiated HeLa-cell modified by fluorescent ubiquitination-based cell-cycle indicator using synchrotron X-ray microbeam

Narita, Ayumi; Kaminaga, Kiichi; Yokoya, Akinari; Noguchi, Miho; Kobayashi, Katsumi*; Usami, Noriko*; Fujii, Kentaro

Radiation Protection Dosimetry, 166(1-4), p.192 - 196, 2015/09

 Times Cited Count:3 Percentile:27.63(Environmental Sciences)

For the knowledge about irradiation effects of mammalian cells depending on the cell cycle, most of them had been analyzed by statistical approches. Our purpose is to establish the method for real-time observation of irradiated cells under a microscope. Fluorescent ubiquitination-based cell cycle indicator (FUCCI) human cancer (HeLa) cells (red indicates G1; green, S/G2) were exposed to a synchrotron X-ray microbeam. Cells in either G1 or S/G2 were selectively irradiated according to cell color observed in the same microscopic field in a culture dish. Time-lapse micrographs of the irradiated cells were acquired for 24 h after irradiation. The cell cycle was strongly arrested by irradiation at S/G2 and never progressed to G1. In contrast, cells irradiated at G1 progress to S/G2 with a similar time course as non-irradiated control cells. These results show single FUCCI cell exposure and live cell imaging are powerful methods for studying radiation effects on the cell cycle.

Journal Articles

Evaluation of ductile damage progress of aluminum single crystal with prior activity of single slip system under tensile loading by using synchrotron white X-ray

Shibano, Junichi*; Kajiwara, Kentaro*; Tsukamoto, Takuya*; kawai, Hirokazu*; Miura, Setsuo*; Zhang, S.*; Shobu, Takahisa; Kobayashi, Michiaki*

Materials Science Forum, 777, p.176 - 181, 2014/02

 Times Cited Count:1 Percentile:55.58

Journal Articles

Evaluation of light transport property in alternative He-3 neutron detectors using ceramic scintillators by a ray-tracing simulation

Ozu, Akira; Takase, Misao*; Kurata, Noritaka*; Kobayashi, Nozomi*; Tobita, Hiroshi; Haruyama, Mitsuo; Kureta, Masatoshi; Nakamura, Tatsuya; Suzuki, Hiroyuki; To, Kentaro; et al.

Proceedings of 2014 IEEE Nuclear Science Symposium and Medical Imaging Conference; 21st International Symposium on Room-Temperature Semiconductor X-ray and $$gamma$$-ray detectors (NSS/MIC 2014), 5 Pages, 2014/00

In Japan Atomic Energy Agency, the helium-3 alternative neutron detector using ceramic scintillators for nuclear safeguards is under development with the support of the government. The alternative detector module consists of four components: an aluminum regular square tube, a light reflecting foil put on the inner surface of the square tube, a rectangular scintillator sheet sintered on a glass plate, and two PMTs provided at both ends of the tube. The scintillator sheet is fit on the diagonal inside the square tube. The light transport property of scintillator lights inside the tube influences on the fundamental performance of the alternative detector. Therefore, the properties of the lights emitted on the surface of the scintillator sheet and scintillation lights passing through the glass plate to the PMTs in several arrangements of the scintillator in the tubes were investigated with a ray-tracing simulation. The results are described in comparison with the experimental results.

Journal Articles

Development of an alternative plutonium canister assay system (APCA) using He-3 alternative neutron detector

Ozu, Akira; Kureta, Masatoshi; Haruyama, Mitsuo; Takase, Misao; Kurata, Noritaka; Kobayashi, Nozomi; Soyama, Kazuhiko; Nakamura, Tatsuya; Sakasai, Kaoru; To, Kentaro; et al.

Kaku Busshitsu Kanri Gakkai (INMM) Nihon Shibu Dai-34-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2013/10

no abstracts in English

Journal Articles

Study on evaluation of ductile damage of aluminum single crystal using synchrotron white X-ray

Shibano, Junichi*; Kiso, Minoru*; Kajiwara, Kentaro*; Shobu, Takahisa; Miura, Setsuo*; Kobayashi, Michiaki*

Zairyo, 62(7), p.443 - 450, 2013/07

The ductile damage progress of the FCC single crystal was verified by the profile analysis using the white X-ray obtained in BL28B2 beam-line of SPring-8. In this study, an aluminum single crystal of the purity 6N was used as a specimen prepared in the I-type geometry for tensile test. The notch was introduced into one side of the center of a parallel part of the specimen by wire electric discharge machining. White X-ray, which has 200 microns in height and 100 microns in width, was incident into the specimen on the Bragg angle of 3$$^{circ}$$ in the horizontal plane using energy dispersive X-ray diffraction technique. As a result, in 1.1% of applied strain, increase of the lattice strain was observed in the direction of about 45$$^{circ}$$ of slant from the notch bottom. In 2.2% of applied strain, the lattice strain reduced in the direction of about 45$$^{circ}$$ of slant from the notch bottom. Non-uniform strain and dislocation density decreased similarly.

Journal Articles

Effect of sweep gas species on tritium release behavior from lithium titanate packed bed during 14MeV neutron irradiation

Kawamura, Yoshinori; Ochiai, Kentaro; Hoshino, Tsuyoshi; Kondo, Keitaro*; Iwai, Yasunori; Kobayashi, Kazuhiro; Nakamichi, Masaru; Konno, Chikara; Yamanishi, Toshihiko; Hayashi, Takumi; et al.

Fusion Engineering and Design, 87(7-8), p.1253 - 1257, 2012/08

 Times Cited Count:15 Percentile:74.97(Nuclear Science & Technology)

Tritium generation and recovery study on lithium ceramic packed bed was started by use of FNS in JAEA. Lithium titanate was selected as tritium breeding material. In this work, the effect of sweep gas species on tritium release behavior was investigated. In case of sweep by helium with 1% of hydrogen, tritium in water form was released sensitively corresponding to the irradiation. This is due to existence of the water vapor in the sweep gas. On the other hand, in case of sweep by dry helium, tritium in gaseous form was released first, and release of tritium in water form was delayed and was gradually increased.

Journal Articles

Detection and activity of iodine-131 in brown algae collected in the Japanese coastal areas

Morita, Takami*; Niwa, Kentaro*; Fujimoto, Ken*; Kasai, Hiromi*; Yamada, Haruya*; Nishiuchi, Ko*; Sakamoto, Tatsuya*; Godo, Waichiro*; Taino, Seiya*; Hayashi, Yoshihiro*; et al.

Science of the Total Environment, 408(16), p.3443 - 3447, 2010/06

 Times Cited Count:13 Percentile:34.22(Environmental Sciences)

Iodine-131 ($$^{131}$$I) was detected in brown algae collected off the Japanese coast. The maximum measured specific activity of $$^{131}$$I in brown algae was 0.37$$pm$$0.010 Bq/kg-wet. Cesium-137 ($$^{137}$$Cs) was also detected in all brown algal samples used in this study. There was no correlation between specific activities of $$^{131}$$I and $$^{137}$$Cs in these seaweeds. Low specific activity and minimal variability of $$^{137}$$Cs in brown algae indicated that past nuclear weapon tests were the source of $$^{137}$$Cs. Although nuclear power facilities are known to be pollution sources of $$^{131}$$I, there was no relationship between the sites where $$^{131}$$I was detected and the locations of nuclear power facilities. Most of the sites where $$^{131}$$I was detected were near big cities with large populations. On the basis of the results, we suggest that the likely pollution source of $$^{131}$$I, detected in brown seaweeds, is not nuclear power facilities, but nuclear medicine procedures.

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

Transmission imaging and strain mapping in the vicinity of internal crack tip using synchrotron white X-ray

Shibano, Junichi*; Kajiwara, Kentaro*; Kiriyama, Koji*; Shobu, Takahisa; Suzuki, Kenji*; Nishimura, Suguru*; Miura, Setsuo*; Kobayashi, Michiaki*

Materials Science Forum, 638-642, p.2476 - 2481, 2010/01

Journal Articles

Observation of internal crack of steel bar by computed tomography and strain mapping near its tip using synchrotron white X-ray

Shibano, Junichi*; Kiriyama, Koji; Kajiwara, Kentaro*; Shobu, Takahisa; Suzuki, Kenji*; Arai, Takayuki*; Miura, Setsuo*; Kobayashi, Michiaki*

Zairyo, 58(7), p.596 - 602, 2009/07

Journal Articles

Study on imaging and strain mapping in the vicinity of internal crack tip using synchrotron white X-ray

Shibano, Junichi*; Kajiwara, Kentaro*; Kiriyama, Koji; Shobu, Takahisa; Suzuki, Kenji*; Nishimura, Suguru*; Miura, Setsuo*; Kobayashi, Michiaki*

Zairyo, 57(7), p.667 - 673, 2008/07

Journal Articles

Progress in R&D efforts on the energy recovery linac in Japan

Sakanaka, Shogo*; Ago, Tomonori*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; Harada, Kentaro*; Hiramatsu, Shigenori*; Honda, Toru*; et al.

Proceedings of 11th European Particle Accelerator Conference (EPAC '08) (CD-ROM), p.205 - 207, 2008/06

Future synchrotron light sources based on the energy-recovery linacs (ERLs) are expected to be capable of producing super-brilliant and/or ultra-short pulses of synchrotron radiation. Our Japanese collaboration team is making efforts for realizing an ERL-based hard X-ray source. We report recent progress in our R&D efforts.

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