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Journal Articles

Mesospheric ionization during substorm growth phase

Murase, Kiyoka*; Kataoka, Ryuho*; Nishiyama, Takanori*; Nishimura, Koji*; Hashimoto, Taishi*; Tanaka, Yoshimasa*; Kadokura, Akira*; Tomikawa, Yoshihiro*; Tsutsumi, Masaki*; Ogawa, Yasunobu*; et al.

Journal of Space Weather and Space Climate (Internet), 12, p.18_1 - 18_16, 2022/06

We identified two energetic electron precipitation (EEP) events during the growth phase of moderate substorms and estimated the mesospheric ionization rate for an EEP event for which the most comprehensive dataset from ground-based and space-born instruments was available. The mesospheric ionization signature reached below 70 km altitude and continued for ~15 min until the substorm onset, as observed by the PANSY radar and imaging riometer at Syowa Station in the Antarctic region. We also used energetic electron flux observed by the Arase and POES 15 satellites as the input for the air-shower simulation code PHITS to quantitatively estimate the mesospheric ionization rate. Combining the cutting-edge observations and simulations, we shed new light on the space weather impact of the EEP events during geomagnetically quiet times, which is important to understand the possible link between the space environment and climate.

Journal Articles

Soft X-ray irradiation induced metallization of layered TiNCl

Kataoka, Noriyuki*; Tanaka, Masashi*; Hosoda, Wataru*; Taniguchi, Takumi*; Fujimori, Shinichi; Wakita, Takanori*; Muraoka, Yuji*; Yokoya, Takashi*

Journal of Physics; Condensed Matter, 33(3), p.035501_1 - 035501_6, 2021/01

 Times Cited Count:0 Percentile:0(Physics, Condensed Matter)

Journal Articles

Transient ionization of the mesosphere during auroral breakup; Arase satellite and ground-based conjugate observations at Syowa Station

Kataoka, Ryuho*; Nishiyama, Takanori*; Tanaka, Yoshimasa*; Kadokura, Akira*; Uchida, Herbert Akihito*; Ebihara, Yusuke*; Ejiri, Mitsumu*; Tomikawa, Yoshihiro*; Tsutsumi, Masaki*; Sato, Kaoru*; et al.

Earth, Planets and Space (Internet), 71, p.9_1 - 9_10, 2019/01

 Times Cited Count:6 Percentile:60.67(Geosciences, Multidisciplinary)

Transient ionization of the mesosphere was detected at around 65 km altitude during the isolated auroral expansion occurred at 2221-2226 UT on June 30, 2017. A general-purpose Monte Carlo particle transport code PHITS suggested that significant ionization is possible in the middle atmosphere due to auroral X-rays from the auroral electrons of $$<$$10 keV.

Journal Articles

Electronic configuration of Mn ions in the $$pi$$-$$d$$ molecular ferromagnetic $$beta$$-Mn phthalocyanine studied by soft X-ray magnetic circular dichroism

Kataoka, Takashi*; Sakamoto, Yuta*; Yamazaki, Yo*; Singh, V. R.*; Fujimori, Atsushi*; Takeda, Yukiharu; Okochi, Takuo*; Fujimori, Shinichi; Okane, Tetsuo; Saito, Yuji; et al.

Solid State Communications, 152(9), p.806 - 809, 2012/05

 Times Cited Count:18 Percentile:63.05(Physics, Condensed Matter)

no abstracts in English

Journal Articles

Electronic structure and magnetism of the diluted magnetic semiconductor Fe-doped ZnO nanoparticles

Kataoka, Takashi*; Kobayashi, Masaki*; Sakamoto, Yuta*; Song, G. S.*; Fujimori, Atsushi*; Chang, F.-H.*; Lin, H.-J.*; Huang, D. J.*; Chen, C. T.*; Okochi, Takuo*; et al.

Journal of Applied Physics, 107(3), p.033718_1 - 033718_7, 2010/02

AA2009-0977.pdf:1.0MB

 Times Cited Count:49 Percentile:86.61(Physics, Applied)

Journal Articles

Experimental observation of bulk band dispersions in the oxide semiconductor ZnO using soft X-ray angle-resolved photoemission spectroscopy

Kobayashi, Masaki*; Song, G.-S.*; Kataoka, Takashi*; Sakamoto, Yuta*; Fujimori, Atsushi; Okochi, Takuo*; Takeda, Yukiharu; Okane, Tetsuo; Saito, Yuji; Yamagami, Hiroshi; et al.

Journal of Applied Physics, 105(12), p.122403_1 - 122403_4, 2009/06

BB2009-1947.pdf:0.84MB

 Times Cited Count:11 Percentile:44.86(Physics, Applied)

Journal Articles

The Small-molecule Bcl-2 inhibitor HA14-1 sensitizes cervical cancer cells, but not normal fibroblasts, to heavy-ion radiation

Hamada, Nobuyuki*; Kataoka, Keiko*; Sora, Sakura*; Hara, Takamitsu*; Omura, Motoko*; Funayama, Tomoo; Sakashita, Tetsuya; Nakano, Takashi*; Kobayashi, Yasuhiko

Radiotherapy and Oncology, 89(2), p.227 - 230, 2008/11

 Times Cited Count:8 Percentile:31.07(Oncology)

Journal Articles

Soft X-ray absorption and photoemission studies of ferromagnetic Mn-implanted 3$$C$$-SiC

Song, G.*; Kobayashi, Masaki*; Hwang, J. I.*; Kataoka, Takashi*; Takizawa, Masaru*; Fujimori, Atsushi; Okochi, Takuo; Takeda, Yukiharu; Okane, Tetsuo; Saito, Yuji; et al.

Japanese Journal of Applied Physics, 47(9), p.7113 - 7116, 2008/09

 Times Cited Count:3 Percentile:15.39(Physics, Applied)

Journal Articles

Electronic structure of Ga$$_{1-x}$$Cr$$_{x}$$N and Si-doping effects studied by photoemission and X-ray absorption spectroscopy

Song, G.*; Kobayashi, Masaki*; Hwang, J. I.*; Kataoka, Takashi*; Takizawa, Masaru*; Fujimori, Atsushi; Okochi, Takuo; Takeda, Yukiharu; Okane, Tetsuo; Saito, Yuji; et al.

Physical Review B, 78(3), p.033304_1 - 033304_4, 2008/07

 Times Cited Count:8 Percentile:39.26(Materials Science, Multidisciplinary)

Journal Articles

Novel separation system of trivalent actinides-combined effects of substituted tris(2-pyridylmethyl)amine ligand and hydrophobic counter-anion

Ishimori, Kenichiro*; Watanabe, Masayuki; Kimura, Takaumi; Yaita, Tsuyoshi; Yamada, Takashi*; Kataoka, Yumiko*; Shinoda, Satoshi*; Tsukube, Hiroshi*

Chemistry Letters, 34(8), p.1112 - 1113, 2005/08

 Times Cited Count:12 Percentile:44.35(Chemistry, Multidisciplinary)

Stereochemical substitution on tripod ligand significantly offered efficient separation of trivalent actinides from trivalent lanthanides. Liquid-liquid extraction using chiral tris(2-pyridylmethyl)amine ligands as an extractant exhibited high efficiency and selectivity for trivalent actinides. A combination of chiral ligand and 2-bromodecanoic acid further enhanced extraction performance for trivalent actinides.

Journal Articles

The Summary report on engineering design activities in the International Thermonuclear Experimental Reactor (ITER) project

Mori, Masahiro; Shoji, Teruaki; Araki, Masanori; Saito, Keiji*; Senda, Ikuo; Omori, Junji*; Sato, Shinichi*; Inoue, Takashi; Ono, Isamu*; Kataoka, Takahiro*; et al.

Nihon Genshiryoku Gakkai-Shi, 44(1), p.16 - 89, 2002/01

no abstracts in English

Journal Articles

ITER engineering design

Shimomura, Yasuo; Tsunematsu, Toshihide; Yamamoto, Shin; Maruyama, So; Mizoguchi, Tadanori*; Takahashi, Yoshikazu; Yoshida, Kiyoshi; Kitamura, Kazunori*; Ioki, Kimihiro*; Inoue, Takashi; et al.

Purazuma, Kaku Yugo Gakkai-Shi, 78(Suppl.), 224 Pages, 2002/01

no abstracts in English

JAEA Reports

None

Fusaeda, Shigeki*; Yanagisawa, Ichiro*; Kataoka, Shinichi*; Shimada, Takashi*; *; *; *

PNC TJ1216 98-007, 46 Pages, 1998/02

PNC-TJ1216-98-007.pdf:1.59MB

None

JAEA Reports

None

Fusaeda, Shigeki*; Yanagisawa, Ichiro*; Kataoka, Shinichi*; Shimada, Takashi*; *; *; *

PNC TJ1216 98-006, 673 Pages, 1998/02

PNC-TJ1216-98-006.pdf:17.22MB

None

JAEA Reports

Development Study on the Geochemical Database

Kataoka, Shinichi*; Kitao, Hideo*; Tachikawa, Hirokazu*; Shimada, Takashi*; Maeda, Kazuto*; Nemoto, Kazuaki*; Yanagisawa, Ichiro*

PNC TJ1216 98-002, 676 Pages, 1998/02

PNC-TJ1216-98-002.pdf:17.64MB

None

Oral presentation

Soft X-ray magnetic circular dichroism and photoemission spectroscopy study of ferromagnetic phthalocyanine

Kataoka, Takashi*; Sakamoto, Yuta*; Yamazaki, Yo*; Fujimori, Atsushi; Takeda, Yukiharu; Okochi, Takuo; Okane, Tetsuo; Saito, Yuji; Yamagami, Hiroshi

no journal, , 

Recently, transition-metal phthalocyanines (Pc) have attracted great interest in many fields of science and technology because of the structural similarities to bio-molecules, their remarkable thermal stability and chemical inertness. One of the most interesting investigations of transition-metal Pc involves their magnetic properties. At low temperature ($$sim$$10 K), the ferromagnetism in $$beta$$-type polycrystals of manganese phthalocyanine (MnPc) has been reported. We have investigated the electronic structure and magnetic interaction in $$beta$$-type polycrystals of the MnPc using X-ray magnetic circular dichroism (XMCD). The XMCD results suggest that the inter-molecular p-d hybridization occurs in the $$beta$$-type polycrystals of MnPc molecules. We will discuss correlation between the inter-molecular interaction and the ferromagnetic coupling in the MnPc molecules.

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

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

Radiation protection of humans in space and aviation; Current states and future needs on the warning system for aviation exposure to SEP (WASAVIES)

Sato, Tatsuhiko; Ishii, Mamoru*; Kataoka, Ryuho*; Kubo, Yuki*; Minoshima, Takashi*; Miyoshi, Yoshizumi*; Nagamatsu, Aiko*; Shiota, Daiko*; Takashima, Takeshi*; Yasuda, Hiroshi*

no journal, , 

Forecast of radiation doses for astronauts as well as aircrews due to the exposure to solar energetic particles (SEP) is one of the greatest challenges in space weather research. In last 5 years, we have developed a WArning System for AVIation Exposure to Solar energetic particles: WASAVIES. In this system, the SEP fluxes incident to the atmosphere are calculated by physics-based models, and they are converted to radiation doses using a database developed on the basis of air-shower simulation. However, it takes approximately 2.5 hours to determine the parameters used in the physics-based models after the detection of GLEs, and thus, the current WASAVIES cannot predict doses during the peak of GLEs. Therefore, we are trying to reduce the time for evaluating the parameters, as well as to develop a nowcast system for the radiation dose due to SEP exposure, under the framework of Project for Solar-Terrestrial Environment Prediction (PSTEP) in Japan. A brief outline of WASAVIES together with our future strategy will be presented at the meeting.

Oral presentation

Radiation dose estimation during the ground level enhancement on 10-11 September 2017 using WASAVIES

Sato, Tatsuhiko; Kataoka, Ryuho*; Shiota, Daiko*; Kubo, Yuki*; Ishii, Mamoru*; Yasuda, Hiroshi*; Miyake, Shoko*; Tsujino, Takashi*

no journal, , 

A ground level enhancement (GLE) event occurred on 10-11 September 2017, associated with X8.2 solar flare exploded at western limb. The magnitude of the GLE was not so large even at the peak, but the duration of the event was longer than average. We briefly report the results of our manually conducted nowcast using WASAVIES (Warning System of AViation Exposure to Solar energetic particles). The maximum radiation dose rate at 12 km flight altitude was estimated to be approximately 2 $$mu$$Sv/h, which is only one-third of the corresponding background dose rate due to the galactic cosmic-ray exposure. This result verified the safety of aircrews and passengers in aviation during this event. The automatic calculation system of WASAVIES was developed, and it will be released via website of Regional Warning Center Japan, International Space Environment Services (RWC Japan, ISES) at NICT in near future.

22 (Records 1-20 displayed on this page)