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Journal Articles

Thermally altered subsurface material of asteroid (162173) Ryugu

Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.

Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03

 Times Cited Count:43 Percentile:96.93(Astronomy & Astrophysics)

Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 $$^{circ}$$C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 $$^{circ}$$C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.

Journal Articles

Nuclear data evaluation of the $$^7$$Li(p,xn) reaction for incident energies up to 200 MeV

Matsumoto, Yuiki*; Watanabe, Yukinobu*; Kunieda, Satoshi; Iwamoto, Osamu

JAEA-Conf 2015-003, p.191 - 196, 2016/03

Neutron emission from the $$^7$$Li(p,n)$$^7$$Be reaction can be divided into two components: a mono-energetic component for the transition to the ground and the 1st excited states and a continuum component formed by $$^7$$Li breakup processes. For the former, we have obtained the differential cross sections by interpolation based on Legendre fitting of available experimental data up to 45 MeV and apply DWBA calculations above 45 MeV. Next, we have applied the CCONE code to DDX calculations of the continuum component, and adjusted pre-equilibrium model parameters to reproduce experimental data well. Finally, both the results are merged and then the evaluated DDX data are completed.

Journal Articles

An Approach to DNA crystallization using the thermal reversible process of DNA duplexes

Chatake, Toshiyuki*; Sazaki, Gen*; Kikko, Tatsuhiko*; Fujiwara, Satoru; Ishikawa, Takuya*; Matsumoto, Osamu*; Morimoto, Yukio*

Crystal Growth & Design, 10(3), p.1090 - 1095, 2010/03

 Times Cited Count:4 Percentile:48.31(Chemistry, Multidisciplinary)

We propose a technique for DNA crystallization using the thermal reversible process of DNA: a conversion between a double-stranded DNA (dsDNA) and two single-stranded DNAs (ssDNAs) with temperatures. We investigated the solubility of the crystals of a DNA hexamer d(CGCGCG) and their melting temperature, at which the thermal conversion occurs. The results obtained suggest that the conversion from a dsDNA to ssDNAs results in an increase in solubility. It was shown that using this temperature-controlled technique, high-grade single crystals of the DNA hexamer could be obtained from a small amount of DNA samples. This easy-to-apply technique would be superior to the conventional vapor diffusion technique in that it allows the solubility of DNA crystals to be controlled with no need for expensive setups.

Journal Articles

Visualization systems on the Information-Technology-Based Laboratory

Suzuki, Yoshio; Sai, Kazunori*; Matsumoto, Nobuko*; Hazama, Osamu

IEEE Computer Graphics and Applications, 23(2), p.32 - 39, 2003/04

 Times Cited Count:6 Percentile:52(Computer Science, Software Engineering)

Visualization systems PATRAS/ITBL and AVS/ITBL, which are based on visualization software PATRAS and AVS/Express respectively, have been developed on a global, heterogeneous computing environment, called Information Technology Based Laboratory (ITBL). PATRAS/ITBL allows for real-time visualization of the numerical results acquired from coupled multi-physics numerical simulations, executed on different hosts situated in remote locations. A collaborative visualization among numerous sites for this type of simulation was also made possible. AVS/ITBL allows for post processing visualization. The scientific data located in remote sites may be selected and visualized on web browser installed in a user terminal. The global structure and main functions of these systems are presented.

Journal Articles

Experimental Study of Effect of Geometry on Density-Head-Driven Instability in Boiling Channels

Kotani, Koichi*; Nakao, Toshitsugu*; Sumida, Isao*; Yokomizo, Osamu*; Matsumoto, Tomoyuki*

Journal of Nuclear Science and Technology, 17(10), p.791 - 793, 1980/10

Oral presentation

Concept of a quake-proof information control and management system for nuclear power plant, 1; Construction of Atomic Energy Grid InfraStructure (AEGIS)

Suzuki, Yoshio; Kushida, Noriyuki; Yamagishi, Nobuhiro; Minami, Takahiro; Matsumoto, Nobuko; Nakajima, Kohei; Nishida, Akemi; Matsubara, Hitoshi; Tian, R.; Hazama, Osamu; et al.

no journal, , 

no abstracts in English

Oral presentation

High-energy ion irradiation effect in CeO$$_{2}$$, 2

Ohara, Kota; Ishikawa, Norito; Sakai, Seiji; Matsumoto, Yoshihiro; Michikami, Osamu*; Ota, Yasuyuki*; Kimura, Yutaka*

no journal, , 

High energy ion irradiation is performed for CeO$$_{2}$$ ceramics. X-ray diffraction and raman spectroscopy analysis suggest that oxygen-deficient ion-track is formed after the irradiation.

Oral presentation

Radiation damage in CeO$$_{2}$$ irradiated with high energy ions, 3

Ohara, Kota; Ishikawa, Norito; Sakai, Seiji; Matsumoto, Yoshihiro; Michikami, Osamu*; Ota, Yasuyuki*; Kimura, Yutaka*

no journal, , 

Irradiation-induced new X-ray diffraction peak is analyzed based on the model that nano-meter size ion tracks are formed in ion-irradiated CeO$$_{2}$$. X-ray diffraction profile can be interpreted by taking account of overlapping effect.

Oral presentation

Chirped pulse amplification laser using Nd:glass zig-zag slab pumped by laser diodes

Sueda, Keiichi*; Kurita, Takashi*; Kawashima, Toshiyuki*; Yamakawa, Koichi; Kawanaka, Junji*; Sekine, Takashi*; Zhao, B.*; Jiang, Y.*; Matsumoto, Osamu*; Fujita, Masayuki*; et al.

no journal, , 

no abstracts in English

Oral presentation

Dynamics of water and formation mechanism of gas hydrates studied by neutron scattering under gas high-pressure

Kikuchi, Tatsuya; Matsumoto, Masakazu*; Yamamuro, Osamu*

no journal, , 

We are studying the formation mechanism of gas hydrates currently attracting much attention in the research field of clathrate hydrates. The largest difficulty for this study is that guest gas molecules hardly dissolve into water under ambient pressure. In order to overcome this difficulty, we prepared aqueous solutions with high solubility (2% at maximum) of guest gases by applying gas high-pressure to water. The quasi-elastic neutron scatterings (QENS) of these samples have been measured to investigate the dynamics of water molecules affected by the guest molecules. The measurements were carried out on AGNES spectrometer installed at JRR-3 (JAEA, Tokai) and maintained by ISSP, University of Tokyo. The guest molecules taken in this study were Ar, Xe, N$$_{2}$$, and CO$$_{2}$$ which have simple molecular structures. The pressure and temperature ranges were 0-100 MPa and 263-363 K, respectively. We analyzed the QENS spectra $$S(Q, omega)$$ based on the jump diffusion model. The diffusion coefficient $$D$$ is smaller than $$D$$ of pure water especially below the hydrate-formation temperature $$T_{rm F}$$ and for the guest molecules with high solubility. These experimental results were reproduced well by MD simulations. It was also found that the gas molecules get closer to each other and the diffusion of water molecules near gas molecules is suppressed, resulting in the smaller diffusion coefficient below $$T_{rm F}$$.

Oral presentation

Technical support for planning and installation of simple ground repository; FY2011 status of support activities for promotion of decontamination in the Fukushima Environmental Safety Center, JAEA

Abe, Hironobu; Ikeda, Koki; Mikake, Shinichiro; Nagasaki, Yasushi; Niizato, Tadafumi; Asazuma, Shinichiro; Aoki, Isao; Ishikawa, Nobuyuki; Ishikawa, Hiroyasu; Ishizaki, Nobuhiro; et al.

no journal, , 

no abstracts in English

Oral presentation

Study on release and transport of aerial radioactive materials in reprocessing plant, 4; Cold test (Part 1) ARF test using mocked fuel reprocessing liquid waste

Tashiro, Shinsuke; Matsumoto, Tetsuya; Kataoka, Osamu; Amano, Yuki; Abe, Hitoshi; Yamane, Yuichi; Yoshida, Kazuo; Ishikawa, Jun; Uchiyama, Gunzo; Ueda, Yoshinori*; et al.

no journal, , 

Measurements on the release ratios of aerial radioactive materials from mocked fuel reprocessing liquid waste under its boiling to dryness process were performed using labo-scaled experiments. Test sample, dissolved 27 elements into nitric acid and arranged to 2M acidity, was heated up to 300 $$^{circ}$$C under the constant air ventilation. Steam, gaseous and airborne materials were collected or absorbed at the condenser, the air filter and the washing bottles. The accumulated release ratios of mocked FP elements from samples were determined using ICP-MS. From the accumulated release ratios determined from the condensed samples, the major release of Cs and Ru could be involved the release of mist and gaseous RuO$$_{4}$$, respectively. Besides, accumulated release ratios of Ru was about 10 to 1000 times higher than Cs, differed from the literature using fuel reprocessing liquid waste. Its differences could be influenced the nitrous acid, which was reduced the generation of RuO$$_{4}$$.

Oral presentation

JAEA's technical experiences and lessons learned for environmental remediation of Fukushima, 2; Technical supports for local governments (decontamination of concrete)

Hata, Katsuro; Ishikawa, Nobuyuki; Uesaka, Takahiro; Sudo, Tomoyuki; Matsumoto, Masaki; Aoki, Isao; Ishizaki, Nobuhiro; Imamura, Hiroaki; Uchida, Shinichi; Kikuchi, Sakae; et al.

no journal, , 

JAEA supports the decontamination activity that the local government of Fukushima carries out. In addition, JAEA carries out instruction and the advice about decontamination. I explain the concrete-based decontamination method of the house which polluted by the accident of the nuclear power plant.

Oral presentation

Study on release and transport of aerial radioactive materials in reprocessing plant, 6; Cold test (Part 3) Effect of FP concentration in mocked HLLW to ARF

Tashiro, Shinsuke; Matsumoto, Tetsuya; Kataoka, Osamu; Amano, Yuki; Abe, Hitoshi; Yamane, Yuichi; Yoshida, Kazuo; Ishikawa, Jun; Uchiyama, Gunzo; Ueda, Yoshinori*; et al.

no journal, , 

The release behavior of radioactive materials from high-level radioactive liquid wastes (HLW) from reprocessing plants under an accidents of boiling to dryness of HLW condition has been studied. The influences of FP concentration in the simulated HLW on the release ratio of FP from the waste were measured in the laboratory-scaled experiments using non-radioactive simulated HLW which was prepared by dissolving 27 FP elements into nitric acid and adjusted to 2 M acidity. The simulated HLW was heated up to 300$$^{circ}$$C under the constant air ventilation condition. The accumulated release ratios of FP elements from samples were determined using ICP-MS analysis. It was found that the accumulated release ratio of Ru was decreased with the increase of the initial Ru concentration in the simulated HLW. However, those of Cs and Nd were not influenced by the initial concentrations of them.

Oral presentation

Technology and development for nuclear forensics; Result of ITWG collaborative materials exercise

Okubo, Ayako; Shinohara, Nobuo; Toda, Nobufumi; Kataoka, Osamu; Matsumoto, Tetsuya

no journal, , 

no abstracts in English

15 (Records 1-15 displayed on this page)
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