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Journal Articles

Application of analysis for assembly of integrated components to steel member connections towards seismic safety assessment of plant structures

Nishida, Akemi; Murakami, Takahiro*; Satoda, Akira*; Asano, Yuya*; Guo, Z.*; Matsukawa, Keisuke*; Oshima, Masami*; Nakajima, Norihiro

Proceedings of 25th International Conference on Structural Mechanics in Reactor Technology (SMiRT-25) (USB Flash Drive), 10 Pages, 2019/08

Exhaustive studies on external events that may pose a threat to the structures of nuclear facilities and evaluations of the structural integrities are critical to safety. One of the components that greatly influence the behavior of the plant structure is the connection of structural members. In particular, the modeling of the connections has relied on empirical methods, and been conservatively designed and evaluated by considering them as pinned or rigid connections. Therefore, in this research, we have aimed to develop a connection modeling method that reproduces more realistic behavior by utilizing a three-dimensional model of the connection. As the first step of this research, we planned to determine the stiffness of the connections of steel structural members. The results confirmed that the connection can be regarded as a partially-restrained connection depending on the connection specifications of the structure, and the prospects for realistic stiffness evaluation of the connection were determined.

Journal Articles

The Succession of bacterial community structure in groundwater from a 250-m gallery in the Horonobe Underground Research Laboratory

Ise, Kotaro; Sasaki, Yoshito; Amano, Yuki; Iwatsuki, Teruki; Nanjo, Isao*; Asano, Takahiro*; Yoshikawa, Hideki

Geomicrobiology Journal, 34(6), p.489 - 499, 2017/07

 Times Cited Count:3 Percentile:73.25(Environmental Sciences)

We investigated the change in bacterial community structure after drilling boreholes, 09-V250-M02 and 09-V250-M03 in the 250 m depth research gallery of Horonobe Underground Research Laboratory (URL). In 09-V250-M02, $$varepsilon$$-Proteobacteria was predominantly detected in the clone library analyses of the groundwater samples conducted immediately after drilling the borehole. All these $$varepsilon$$-Proteobacteria clones are closely related to ${{it Arcobacter spp}}$. which is known as sulfide oxidizing chemoautotrophic bacteria. After four years, the microbial structure was drastically changed and most detected OTUs were uncultured species such as candidate division OP9 and Chloroflexi relatives which are frequently detected in deep-sea sediments.

Journal Articles

High-power test of annular-ring coupled structures for the J-PARC linac energy upgrade

Tamura, Jun; Ao, Hiroyuki; Nemoto, Yasuo; Asano, Hiroyuki*; Suzuki, Takahiro*

Journal of the Korean Physical Society, 66(3), p.399 - 404, 2015/02

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

ACSs are going to increase the beam energy of the J-PARC linac from 181 to 400 MeV. The 2011 Tohoku earthquake damaged the J-PARC facilities and the cavity conditioning was interrupted for two years. After the restoration of the facility, the two ACS cavities (M01 and M11) were conditioned. They achieved to 15-20% above the designed accelerating field of 4.2 MV/m. Since M01 was conditioned six years ago, the conditioning time required for M01 was drastically reduced from that for the first time. During the high-power operation for M11, which is an unique cavity equipped with a capacitive iris in a waveguide, no significant increase of the temperature and the discharge rate around the capacitive iris was observed. The vacuum pressure was sufficiently low (4$$times$$10$$^{-6}$$ Pa) even from the view point of beam loss due to residual gas scattering. The more stable operation can be expected through one-month conditioning before beam commissioning.

Journal Articles

Resuming of ACS high-power test for J-PARC Linac Energy Upgrade

Tamura, Jun; Ao, Hiroyuki; Nemoto, Yasuo; Asano, Hiroyuki*; Suzuki, Takahiro*

Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.437 - 439, 2014/06

no abstracts in English

Journal Articles

Occurrence and potential activity of denitrifiers and methanogens in groundwater at 140 m depth in Pliocene diatomaceous mudstone of northern Japan

Katsuyama, Chie*; Nashimoto, Hiroaki*; Nagaosa, Kazuyo*; Ishibashi, Tomotaka*; Furuta, Kazuki*; Kinoshita, Takeshi*; Yoshikawa, Hideki; Aoki, Kazuhiro; Asano, Takahiro*; Sasaki, Yoshito; et al.

FEMS Microbiology Ecology, 86(3), p.532 - 543, 2013/12

 Times Cited Count:8 Percentile:69.83(Microbiology)

Anaerobic microbial activity has a major influence on the subsurface environment, and should be considered in subsurface activities including the construction of radioactive waste repositories. We investigated denitrification and methanogenesis in anoxic groundwater from 140 m depth in two boreholes, where the redox potential fluctuated. The average maximum potential denitrification rates, measured under anaerobic conditions in the two boreholes using an $$^{15}$$N tracer. Methanogenesis candidates were detected by 16S rRNA gene analysis. Although the stable isotope signatures suggested that some of the dissolved methane was of biogenic origin, no potential for methane production was evident during the incubations. The groundwater at 140 m depth did not contain oxygen, had an Eh ranging from -144 to 6.8 mV, and was found to be a potential field for denitrification.

Journal Articles

Beam loss reduction by the beam duct realignment in the J-PARC linac beam transport line

Tamura, Jun; Ao, Hiroyuki; Asano, Hiroyuki; Ikegami, Masanori*; Maruta, Tomofumi; Miura, Akihiko; Morishita, Takatoshi; Oguri, Hidetomo; Ouchi, Nobuo; Sawabe, Yuki*; et al.

Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.377 - 380, 2013/08

In the J-PARC linac, almost all the cavities and magnets have been precisely aligned because the accelerator tunnel has been deformed by the 2011 Tohoku Earthquake. In the beam transport line called MEBT2 and A0BT at the downstream of the drift tube linac, the beam duct has been roughly aligned after the precise alignment of the quadruple doublets. During the first beam operation after the earthquake, remarkable beam loss and residual radiation have been recognized at the MEBT2 and A0BT. As the result of the duct position measurement, the misalignement including over 10 mm shift from the beam axis was found. By conducting the beam duct realignment, the beam loss and the residual radiation were successfully decreased. In this paper, the procedure of the beam duct alignment and the beam loss due to the misalignment are described.

Journal Articles

Microprocessing of arched bridge structures with epoxy resin by proton beam writing

Takano, Katsuyoshi*; Asano, Atsushi*; Maeyoshi, Yuta*; Marui, Hiromi*; Omichi, Masaaki*; Saeki, Akinori*; Seki, Shu*; Sato, Takahiro; Ishii, Yasuyuki; Kamiya, Tomihiro; et al.

Journal of Photopolymer Science and Technology, 25(1), p.43 - 46, 2012/07

 Times Cited Count:2 Percentile:91.32(Polymer Science)

Journal Articles

An Investigation of microbial effect as biofilm formation on radionuclide migration

Yoshikawa, Hideki; Kawakita, Masakazu*; Fujiwara, Kazuhiro*; Sato, Tomofumi; Asano, Takahiro*; Sasaki, Yoshito

Materials Research Society Symposium Proceedings, Vol.1475, p.617 - 622, 2012/06

Since it was suggested that the microbes have ability to generate their biofilm in deep underground condition, we examined the effects of biofilm on radionuclide migration scenario. To estimate the effect on matrix diffusion, through diffusion experiment for a biofilm of Desulfovivrio desullfuricans were performed. The effective diffusion coefficient of the biofilm was 10$$^{-10}$$ m$$^{2}$$/s order which was about ten times smaller than that in free water. It is suggesting that the microbes and biofilm will not interfere with matrix diffusion as a retardation of radionuclide in rock.

Journal Articles

Fabrication of concave and convex structure array consisted of epoxy long-nanowires by light and heavy ion beams lithography

Takano, Katsuyoshi*; Sugimoto, Masaki; Asano, Atsushi*; Maeyoshi, Yuta*; Marui, Hiromi*; Omichi, Masaaki*; Saeki, Akinori*; Seki, Shu*; Sato, Takahiro; Ishii, Yasuyuki; et al.

Transactions of the Materials Research Society of Japan, 37(2), p.237 - 240, 2012/06

Journal Articles

Fabrication of poly(9,9'-dioctylfluorene)-based nano- and microstructures by proton beam writing

Maeyoshi, Yuta*; Takano, Katsuyoshi*; Asano, Atsushi*; Marui, Hiromi*; Omichi, Masaaki*; Sato, Takahiro; Kamiya, Tomihiro; Ishii, Yasuyuki; Okubo, Takeru; Koka, Masashi; et al.

Japanese Journal of Applied Physics, 51(4R), p.045201_1 - 045201_4, 2012/04

 Times Cited Count:1 Percentile:94.53(Physics, Applied)

JAEA Reports

Study on investigation of microbial effects for geological disposal, 2 (Joint research)

Tochigi, Yoshikatsu; Yoshikawa, Hideki; Aoki, Kazuhiro; Yui, Mikazu; Asano, Takahiro*; Honjo, Hideko*; Haginuma, Masashi*; Kawakami, Yasushi*; Suzuki, Kazunori*

JAEA-Research 2008-025, 55 Pages, 2008/03


Results of joint research on fiscal year 2006 between Japan Atomic Energy Agency (JAEA) and Institute of Research and Innovative (IRI) titled as "Study on investigation of microbial effects for geological disposal" are described in this report. The objective of this study is to develop a method for estimating microbial effects for barrier performance of geological disposal site. The modeling was performed to examine the effect on the change in groundwater chemistry (mainly by electron acceptors) by microbial metabolism as well as microbial activities. In order to use the data (chemical composition, biomass, etc.) in the MINT code, groundwater was collected from the drilled well prepared for chemical and microbial analyses of groundwater. The well was prepared in observation field near Horonobe Underground Research Center of JAEA in fiscal year 2006. Then, numerical modeling using collected data of groundwater with numerical modeling program code "MINT" considering microbial effects was carried out. The modeling was carried out to evaluate the microbial effect for stability of chemical and microbial composition of groundwater. As the result of the modeling, relatively low microbial effect for groundwater composition was observed in particular for the concentration of dissolved methane, methanogen, sulfur reducing bacteria (SRB) and sulfur ion. The result shows that low redox potential is stable in the well in spite of shallow depth.

Journal Articles

Systematic study for the shell effect in the fission fragment mass distribution reptured from neutron rich nuclei

Ota, Masahisa*; Tatsuda, Sayuki*; Yamamoto, Kazuyuki*; Asano, Tomomasa*; Wada, Takahiro*; Hashizume, Kazuaki*; Sumiyoshi, Kosuke*; Otsuki, Kaori*; Kajino, Toshitaka*; Koura, Hiroyuki; et al.

Nuclear Physics A, 805(2), p.558 - 560, 2008/02

The data base for the fission fragment mass distribution used in the r-process network calculation is constructed. The differences appeared in the final element abundance calculated with and without fission process are demonstrated and the mass region modified by the fission products is presented.

Journal Articles

Novel UV-induced photografting process for preparing poly(tetrafluoroethylene)-based proton-conducting membranes

Asano, Masaharu; Chen, J.; Maekawa, Yasunari; Sakamura, Takahiro*; Kubota, Hitoshi*; Yoshida, Masaru

Journal of Polymer Science, Part A; Polymer Chemistry, 45(13), p.2624 - 2637, 2007/07

A novel process comprising UV-induced photografting of styrene into polytetrafluoroethylene (PTFE) films and subsequent sulfonation has been developed for preparing proton-conducting membranes. The significance of this process is that the polystyrene can graft throughout the PTFE films. Even through the degree of grafting was lower than 10 %, the proton conductivity of the newly prepared membranes can reach a value similar to Nafion. In comparison with $$gamma$$-ray radiation grafting, UV photografting is less damaging to the membranes because significant degradation of the PTFE main chains can be avoided.

Journal Articles

Therapeutic effects of a $$^{186}$$Re-complex-conjugated bisphosphonate for the palliation of metastatic bone pain in an animal model

Ogawa, Kazuma*; Mukai, Takahiro*; Asano, Daigo*; Kawashima, Hidekazu*; Kinuya, Seigo*; Shiba, Kazuhiro*; Hashimoto, Kazuyuki; Mori, Hirofumi*; Saji, Hideo*

Journal of Nuclear Medicine, 48(1), p.122 - 127, 2007/01

We developed a highly stable rhenium-186 ($$^{186}$$Re)-MAG3 complex-conjugated bisphosphonate, ($$^{186}$$Re-MAG3-HBP), for the treatment of painful bone metastases. This agent showed a superior biodistribution as a bone-seeking agent in normal mice when compared with $$^{186}$$Re-HEDP. In this study, we evaluated the therapeutic effects of $$^{186}$$Re-MAG3-HBP using an animal model of bone metastasis. In the rats treated with $$^{186}$$Re-HEDP, tumor growth was comparable to that in untreated rats. In contrast, when $$^{186}$$Re-MAG3-HBP was administered, tumor growth was significantly inhibited. Allodynia induced by bone metastasis was attenuated by treatment with $$^{186}$$Re-MAG3-HBP or $$^{186}$$Re-HEDP, but $$^{186}$$Re-MAG3-HBP tended to be more effective. These results indicate that $$^{186}$$Re-MAG3-HBP could be useful as a therapeutic agent for the palliation of metastatic bone pain.

Journal Articles

Preparation of ETFE-based fuel cell membranes using UV-induced photografting and electron beam-induced crosslinking techniques

Chen, J.; Asano, Masaharu; Maekawa, Yasunari; Sakamura, Takahiro*; Kubota, Hitoshi*; Yoshida, Masaru

Journal of Membrane Science, 283(1-2), p.373 - 379, 2006/10

 Times Cited Count:18 Percentile:42.87(Engineering, Chemical)

A novel process comprising UV-induced photografting of styrene into poly(tetrafluoroethylene-co-ethylene) (ETFE) films in vapor and liquid phases, followed by electron beam-induced crosslinking has been developed for preparing polymer electrolyte membranes. The significance of this process is that the photografted polystyrene chains can completely penetrate into the base ETFE film; the membranes show proton conductibility available for fuel cell applications. On one hand, the proton conductivity of the liquid-phase photografted electrolyte membranes is higher than the vapor-phase one, and is anisotropic in the surface and thickness directions. On the other hand, radiation-induced crosslinking greatly improves the chemical stability of the resultant fuel cell membranes, and maintains the surface concentration of sulfonic acid groups at its higher level.

Journal Articles

Preparation of fuel cell membranes by photografting in vapor and liquid phases

Chen, J.; Asano, Masaharu; Maekawa, Yasunari; Sakamura, Takahiro*; Kubota, Hitoshi*; Yoshida, Masaru

Electrochemical and Solid-State Letters, 9(5), p.G184 - G186, 2006/00

 Times Cited Count:8 Percentile:65.46(Electrochemistry)

UV radiation-induced photografting of styrene into ETFE films for the preparation of fuel cell membranes was carried out. The proton conductivity in thickness direction of membranes prepared by the vapor- and liquid-phase photografting can reach as high as 0.065 and 0.087 S/cm, respectively. The higher conductivity in the liquid-phase grafting is close to the homogeneity of graft chain distribution in the membrane.

Journal Articles

Polytetrafluoroethylene-based proton-conducting membranes prepared by ultraviolet-induced photografting

Chen, J.; Asano, Masaharu; Maekawa, Yasunari; Sakamura, Takahiro*; Kubota, Hitoshi*; Yoshida, Masaru

Electrochemical and Solid-State Letters, 9(11), p.G326 - G329, 2006/00

 Times Cited Count:5 Percentile:75.48(Electrochemistry)

A novel process comprising UV-induced photografting of styrene into PTFE films and subsequent sulfonation has been developed for preparing proton-conducting membranes. The significance of this process is that the graft chains can penetrate throughout the PTFE base films; the resultant sulfonated electrolyte membrane with a low degree of grafting near 7% shows higher proton conductibility and better mechanical properties, similar to those of Nafion membrane. Furthermore, the performances of the UV-photografted electrolyte membranes are better as compared to those of the radiation grafted electrolyte membranes.

Journal Articles

Absolute measurement of extremely high intense photons using calorimetric method

Asano, Yoshihiro; Kishi, Noriyuki*; Moriya, Takahiro*; Miura, Yuta*; Inoue, Katsuaki*

AIP Conference Proceedings 705, p.568 - 571, 2004/04

no abstracts in English

Journal Articles

Measurement of absolute intensity for high energy SR photons using calorimeter

Asano, Yoshihiro; Kishi, Noriyuki*; Moriya, Takahiro*

AIP Conference Proceedings 705, p.564 - 567, 2004/00

no abstracts in English

Journal Articles

Beam-palarization asymmetries for the $$p$$($$overrightarrow{gamma}$$,$$K$$$$^{+}$$)$$Lambda$$ and $$p$$($$overrightarrow{gamma}$$,$$K$$$$^{+}$$)$$Sigma$$$$^{0}$$ reactions for $$E$$$$_{gamma}$$=1.5-2.4 GeV

Zegers, R. G. T.*; Sumihama, Mizuki*; Ahn, D. S.*; Ahn, J. K.*; Akimune, Hidetoshi*; Asano, Yoshihiro; Chang, W. C.*; Dat$'e$, S.*; Ejiri, Hiroyasu*; Fujimura, Hisako*; et al.

Physical Review Letters, 91(9), p.092001_1 - 092001_4, 2003/08

 Times Cited Count:124 Percentile:4.61(Physics, Multidisciplinary)

no abstracts in English

54 (Records 1-20 displayed on this page)