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Journal Articles

Protein hydration and its freezing phenomena; Toward the application for cell freezing and frozen food storage

Yamamoto, Naoki*; Nakanishi, Masahiro*; Rajan, R.*; Nakagawa, Hiroshi

Biophysics and Physicobiology (Internet), 18, p.284 - 288, 2021/12

Water is an indispensable solvent for living things. $$sim$$60% of our body is composed of water, the lack of which causes lots of fatal problems. It has also been known that protein function is performed only when it accompanies water molecules around the surface, i.e. hydration water molecules. Therefore, it is essential to understand how water and biological component interact with each other in the view point of structure and dynamics. Freezing is a fundamental and simple phenomenon of water, and thus can be used as a probe for the purpose. Furthermore, preservation of cells and proteins under low temperature is crucial for numerous applications, which in turn triggers a myriad of undesirable consequences because of the freezing.

Journal Articles

Dynamics of proteins with different molecular structures under solution condition

Inoue, Rintaro*; Oda, Takashi*; Nakagawa, Hiroshi; Tominaga, Taiki*; Saio, Tomohide*; Kawakita, Yukinobu; Shimizu, Masahiro*; Okuda, Aya*; Morishima, Ken*; Sato, Nobuhiro*; et al.

Scientific Reports (Internet), 10, p.21678_1 - 21678_10, 2020/12

 Times Cited Count:3 Percentile:15.31(Multidisciplinary Sciences)

Incoherent quasielastic neutron scattering (iQENS) is a fascinating technique for investigating the internal dynamics of protein. However, both low flux of neutron beam and absence of analytical procedure for extracting the internal dynamics from iQENS profile have been obstacles for studying it under physiological condition (in solution). Thanks to the recent development of neutron source, spectrometer and computational technique, they enable us to decouple internal dynamics, translational and rotational diffusions from the iQENS profile. The internal dynamics of two proteins: globular domain protein (GDP) and intrinsically disordered protein (IDP) in solution were studied. It was found that the average relaxation rate of IDP was larger than that of GDP. Through the detailed analyses on their internal dynamics, it was revealed that the fraction of mobile H atoms in IDP was much higher than that in GDP. Interestingly, the fraction of mobile H atoms was closely related to the fraction of H atoms on highly solvent exposed surfaces. The iQENS study presented that the internal dynamics were governed by the highly solvent exposed amino acid residues depending upon protein molecular architectures.

Journal Articles

A Prospect of development and use of the virtual tour of the physical protection exercise field

Nakagawa, Yosuke; Sukegawa, Hidetoshi; Naoi, Yosuke; Inoue, Naoko; Noro, Naoko; Okuda, Masahiro

Dai-41-Kai Nihon Kaku Busshitsu Kanri Gakkai Nenji Taikai Kaigi Rombunshu (Internet), 4 Pages, 2020/11

The physical protection exercise field, a facility equipped with various types of equipment such as sensors, cameras and fences that are used at nuclear facilities, is an effective tool for training on nuclear security at ISCN/JAEA, if it is carried out in-person. Due to the COVID-19 pandemic, the virtual tour of the facility is developed for the online training courses so that they could be more effective. The article explains the initial development of the virtual tour with some improvement inspired by using it on some occasions as well as a prospect of effective use of the virtual tour based on its characteristics.

Journal Articles

Evaluation of oxidation efficiency of hydrophobic palladium catalyst for $$^{3}$$H monitoring in radioactive gaseous waste

Furutani, Misa; Kometani, Tatsunari; Nakagawa, Masahiro; Ueno, Yumi; Sato, Junya; Iwai, Yasunori*

Hoken Butsuri (Internet), 55(2), p.97 - 101, 2020/06

Herein, an oxidation catalyst was introduced after heating it to 600$$^{circ}$$C to oxidize tritium gas (HT) existing in exhaust into tritiated water vapor (HTO). This study aims to establish a safer $$^{3}$$H monitoring system by lowering the heating temperature required for the catalyst. In these experiments, which were conducted in the Nuclear Science Research Institute, Japan Atomic Energy Agency, cupric oxide, hydrophobic palladium/silicon dioxide (Pd/SiO$$_{2}$$), and platinum/aluminum oxide (Pt/Al$$_{2}$$O$$_{3}$$) catalysts were ventilated using standard hydrogen gas. After comparing the oxidation efficiency of each catalyst at different temperatures, we found that the hydrophobic Pd/SiO$$_{2}$$ and Pt/Al$$_{2}$$O$$_{3}$$ catalysts could oxidize HT into HTO at 25$$^{circ}$$C.

JAEA Reports

Case studies of radiation dose assessment in emergency situation of nuclear facilities

Kawasaki, Masatsugu; Nakajima, Junya; Yoshida, Keisuke; Kato, Saori; Nishino, Sho; Nozaki, Teo; Nakagawa, Masahiro; Tsunoda, Junichi; Sugaya, Yuki; Hasegawa, Rie; et al.

JAEA-Data/Code 2017-004, 57 Pages, 2017/03


In emergency situation of nuclear facilities, we need to estimate the radiation dose due to radiation and radioactivity to grasp the influence range of the accident in the early stage. Therefore, we prepare the case studies of dose assessment for public exposure dose and personal exposure dose and contribute them to emergency procedures. This document covers about accidents of nuclear facilities in Nuclear Science Research Institute and past accident of nuclear power plant, and it can be used for inheritance of techniques of emergency dose assessment.

Journal Articles

Evaluation of oxidation efficiency of hydrophobic palladium catalyst for $$^{14}$$C monitoring in gaseous radioactive waste

Ueno, Yumi; Nakagawa, Masahiro; Sato, Junya; Iwai, Yasunori

Hoken Butsuri, 51(1), p.7 - 11, 2016/03

In the Nuclear Science Research Institute, Japan Atomic Energy Agency (JAEA), in order to oxidize $$^{14}$$C, which exists in various chemical forms in exhaust, into $$^{14}$$CO$$_{2}$$, a copper oxide (CuO) catalyst is introduced after heating to 600$$^{circ}$$C. Our goal was to establish a safer $$^{14}$$C monitoring system by lowering the heating temperature required for the catalyst; therefore, we developed a new hydrophobic palladium/silicon dioxide (Pd/SiO$$_{2}$$) catalyst that makes the carrier's surface hydrophobic. In these experiments, catalysts CuO, platinum/aluminum oxide (Pt/Al$$_{2}$$O$$_{3}$$), palladium/zirconium dioxide (Pd/ZrO$$_{2}$$), hydrophobic Pd/SiO$$_{2}$$, and hydrophilic Pd/SiO$$_{2}$$ were ventilated with standard methane gas, and we compared the oxidation efficiency of each catalyst at different temperatures. As a result, we determined that the hydrophobic Pd/SiO$$_{2}$$ catalyst had the best oxidation efficiency. By substituting the currently used CuO catalyst with the hydrophobic Pd/SiO$$_{2}$$ catalyst, we will be able to lower the working temperature from 600$$^{circ}$$C to 300$$^{circ}$$C and improve the safety of the monitoring process.

JAEA Reports

Survey of radiation protection creiteria following the accident at the Fukushima Dai-ichi Nuclear Power Plant

Yamada, Katsunori; Fujii, Katsutoshi; Kanda, Hiroshi; Higashi, Daisuke; Kobayashi, Toshiaki; Nakagawa, Masahiro; Fukami, Tomoyo; Yoshida, Keisuke; Ueno, Yumi; Nakajima, Junya; et al.

JAEA-Review 2013-033, 51 Pages, 2013/12


After the accident at Fukushima Dai-ichi Nuclear Power Plant, various numerical criteria relevant to radiation protection were defined. We surveyed these criteria through internet. As a result of survey, the following 13 items were identified: (1) criteria for taking stable iodine tablets, (2) criteria for the screening of surface contamination, (3) evacuation area, sheltering area, etc., (4) activity concentrations in food, drinking water, etc., (5) dose limit for radiation workers engaged in emergency work, (6) guideline levels of radioactive substances in bathing areas, (7) criteria for use of school buildings and schoolyards, (8) restriction on planting rice, (9) acceptable activity concentrations in feedstuff, (10) acceptable activity concentrations in compost, (11) criteria for export containers and ships, (12) criteria for contaminated waste, (13) standards for radiation workers engaged in decontamination work. In this report, the basis of and issues on these criteria are summarized.

Journal Articles

Evaluation of protection factors of a breath-responsive-powered air-purifying respirator

Nakagawa, Masahiro; Nojima, Shun; Fujii, Katsutoshi; Shishido, Nobuhito; Sakai, Toshiya; Umehara, Takashi; Shimizu, Isamu

Hoken Butsuri, 47(3), p.189 - 193, 2012/10

It is essential to wear an air-purifying respirator in the radiation works in a contaminated atmosphere. A breath-responsive-powered air-purifying respirator (BR-PAPR) has been recently developed. However, no research has yet been conducted to determine the protection factor (PF) of the BR-PAPR in actual workplaces. In this study, the PFs of the BR-PAPR were measured by a man-test apparatus and compared with those of a non-powered full face mask. The PFs were measured under three different situations; normal wearing condition, clogging the filter and leaving a gap between the face and the mask. Under these situations, it was found that the PFs of the BR-PAPR are higher than those of the non-powered full face mask. PFs greater than 4000 were obtained for 95% of the subjects who wear the BR-PAPR, and PFs over 6667, the upper limit of the man-test apparatus, were obtained for 49% of them. The questionnaire survey was conducted for workers. The results showed that the workers feel a reduced burden when they wear the BR-PAPR. The results of this study showed high protection performance and operation efficiency of the BR-PAPR.

Journal Articles

Identified charged hadron production in $$p + p$$ collisions at $$sqrt{s}$$ = 200 and 62.4 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Armendariz, R.*; et al.

Physical Review C, 83(6), p.064903_1 - 064903_29, 2011/06

 Times Cited Count:176 Percentile:99.42(Physics, Nuclear)

Transverse momentum distributions and yields for $$pi^{pm}, K^{pm}, p$$, and $$bar{p}$$ in $$p + p$$ collisions at $$sqrt{s}$$ = 200 and 62.4 GeV at midrapidity are measured by the PHENIX experiment at the RHIC. We present the inverse slope parameter, mean transverse momentum, and yield per unit rapidity at each energy, and compare them to other measurements at different $$sqrt{s}$$ collisions. We also present the scaling properties such as $$m_T$$ and $$x_T$$ scaling and discuss the mechanism of the particle production in $$p + p$$ collisions. The measured spectra are compared to next-to-leading order perturbative QCD calculations.

Journal Articles

Azimuthal correlations of electrons from heavy-flavor decay with hadrons in $$p+p$$ and Au+Au collisions at $$sqrt{s_{NN}}$$ = 200 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Aramaki, Y.*; et al.

Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04

 Times Cited Count:7 Percentile:46.42(Physics, Nuclear)

Measurements of electrons from the decay of open-heavy-flavor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled $$p+p$$ collisions. Here we extend these studies to two particle correlations where one particle is an electron from the decay of a heavy flavor meson and the other is a charged hadron from either the decay of the heavy meson or from jet fragmentation. These measurements provide more detailed information about the interaction between heavy quarks and the quark-gluon matter. We find the away-side-jet shape and yield to be modified in Au+Au collisions compared to $$p+p$$ collisions.

Journal Articles

Electronic properties of femtosecond laser induced modified spots on single crystal silicon carbide

Tomita, Takuro*; Iwami, Masahiro*; Yamamoto, Minoru*; Deki, Manato*; Matsuo, Shigeki*; Hashimoto, Shuichi*; Nakagawa, Yoshinori*; Kitada, Takahiro*; Isu, Toshiro*; Saito, Shingo*; et al.

Materials Science Forum, 645-648, p.239 - 242, 2010/04

no abstracts in English

JAEA Reports

Conceptual study for new $$^{99}$$Mo-production facility in JMTR

Kimura, Akihiro; Iimura, Koichi; Hosokawa, Jinsaku; Izumo, Hironobu; Hori, Naohiko; Nakagawa, Tetsuya; Kanno, Masaru; Ishihara, Masahiro; Kawamura, Hiroshi

JAEA-Review 2009-072, 18 Pages, 2010/03


JAEA has a plan to produce $$^{99}$$Mo, a parent nuclide of $$^{99m}$$Tc. At present, radioisotopes are indispensable for a diagnosis and treatment in the medical field. Demand of $$^{99m}$$Tc (half life 6h) used as a radiopharmaceutical increases up year by year. Moreover, the expansion of demand will be expected in future. However, the supply of $$^{99}$$Mo in Japan depends fully on the import from foreign countries. Therefore, it is necessary to supply $$^{99}$$Mo stably by the domestic production. There are two methods of $$^{99}$$Mo (half life 65.9h) production; the one is the nuclear fission (n,fiss) method, and the other is the (n,$$gamma$$) method using the $$^{98}$$Mo target. $$^{99}$$Mo production in the JMTR with the (n,$$gamma$$) method was studied and evaluated. As a result, it was found that the partial amount of $$^{99}$$Mo demand is possible to supply stably if a new hydraulic-rabbit-irradiation-facility (HR) is used.

JAEA Reports

Current status of JMTR refurbishment project

Kaminaga, Masanori; Niimi, Motoji; Hori, Naohiko; Takahashi, Kunihiro; Kanno, Masaru; Nakagawa, Tetsuya; Nagao, Yoshiharu; Ishihara, Masahiro; Kawamura, Hiroshi

JAEA-Review 2009-056, 20 Pages, 2010/02


The JMTR is a light water moderated and cooled, beryllium reflected tank- type reactor using LUE silicide plate-type fuels. Its thermal power is 50 MW, maximum thermal and fast neutron flux is 4 $$times$$ 10$$^{18}$$ m$$^{-2}$$s$$^{-1}$$. First criticality was achieved in March 1968, and its operation was stopped from August, 2006 for the refurbishment. The refurbishment is scheduled from the beginning of FY2007 to the end of FY2010. The renewed and upgraded JMTR will be re-started from FY2011. An investigation on aged components (aged-investigation) was carried out for concrete structures of the JMTR reactor building, exhaust stack, etc., and for tanks in the primary cooling system, heat exchangers, pipes in the secondary cooling system, cooling tower, emergency generators and so on, in order to identify their integrity. The aged-investigation was carried out at the beginning of FY2007. As a result, some components were decided to replace from viewpoints of future maintenance and improvement of reliability, and some components or structures were decided to repair. A visual inspection of inner side of the pressure vessel was carried out using an underwater camera in FY2008, and no serious damage was observed. Up to now, refurbishment works are in progress according to the planned schedule. In this paper, current status of JMTR refurbishment project is presented.

Journal Articles

Temperature evaluation of core components of HTGR at depressurization accident considering annealing recovery on thermal conductivity of graphite

Sumita, Junya; Shibata, Taiju; Nakagawa, Shigeaki; Hanawa, Satoshi; Iyoku, Tatsuo; Ishihara, Masahiro

Transactions of 18th International Conference on Structural Mechanics in Reactor Technology (SMiRT-18), p.4822 - 4828, 2005/08

Graphite materials are used for structural components in High Temperature Gas-Cooled Reactor (HTGR) core because of their excellent thermo/mechanical properties. Thermal conductivity of graphite components is reduced by neutron irradiation in reactor operation. The reduced conductivity is expected to be recovered by thermal annealing effect when irradiated graphite component is heated above irradiated temperature. In the present study, temperature analyses considering the annealing effect of the HTGR core at a depressurization accident were carried out and influence of annealing effect on maximum fuel temperature was investigated. The analyses show that the annealing effect can reduce the fuel temperature about 100$$^{circ}$$C at the maximum, and it is possible to evaluate the maximum fuel temperature more appropriately. It was also shown that the core-temperature of High Temperature Engineering Test Reactor (HTTR) at the safety demonstration tests can be analyzed with the developed evaluation method considering annealing effect.

Journal Articles

Reactor internals design

Sumita, Junya; Ishihara, Masahiro; Nakagawa, Shigeaki; Kikuchi, Takayuki; Iyoku, Tatsuo

Nuclear Engineering and Design, 233(1-3), p.81 - 88, 2004/10

 Times Cited Count:4 Percentile:29.52(Nuclear Science & Technology)

A High Temperature Gas-cooled Reactor is particularly attractive due to its capability of producing high temperature helium gas and its possibility to exploit inherent safety characteristic. To achieve high temperature helium-gas, reactor internals are made of graphite and heat resistant materials, its surroundings are composed of metals. The reactor internals of the HTTR consist of graphite and metallic core support structures and shielding blocks. This paper describes the reactor internal design of the HTTR, especially the core support graphite structures, and the program of an in-service inspection.

Journal Articles

Ca(II)-Fe(II) and Ca(II)-Mn(II) Exchange Selectivity of Bentonite

Saeki, Kazutoshi*; Nakagawa, Kei*; Wada, Shinichiro*; Shibata, Masahiro; Horoshiro, Yoshinari*; Jinno, Kenji*

Nendo Kagaku, 42(1), p.1 - 5, 2002/08


JAEA Reports


Nakagawa, Kei*; Jinno, Kenji*; Ijiri, Yuji; Watari, Shingo; ; Uchida, Masahiro

JNC TY8400 99-005, 121 Pages, 1999/06


no abstracts in English

JAEA Reports


Jinno, Kenji*; Nakagawa, Kei*; *; ; Ijiri, Yuji*; Watari, Shingo; Webb, E. K.*; Kanazawa, Yasuo*; Uchida, Masahiro

PNC TY1606 97-001, 44 Pages, 1997/03


no abstracts in English

Oral presentation

Evaluation of protection factors provided by breath responsive powered air purifying respirator

Nakagawa, Masahiro; Nojima, Shun; Fujii, Katsutoshi; Shishido, Nobuhito; Sakai, Toshiya; Umehara, Takashi; Shimizu, Isamu

no journal, , 

no abstracts in English

Oral presentation

Performance tests of a mask fitting tester for use in nuclear facilities

Nakagawa, Masahiro; Kato, Takuya; Nojima, Shun; Sakai, Toshiya; Shishido, Nobuhito; Umehara, Takashi

no journal, , 

Mask fitting tester "MT-03" is widespread as educational equipment in medical institution and industrial organization. However, there are few examples introduced in order to check the protection performance of purifying respirators in nuclear facilities. In this study, we compared protection factors obtained by MT-03 and those obtained by Mask-man test apparatus "MT-100N". As a result, although the change of measurement result is larger and measured value is higher than that of MT-100N, it was found that protection performance can be checked appropriately.

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