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Yuguchi, Takashi*; Ito, Daichi*; Yokoyama, Tatsunori; Sakata, Shuhei*; Suzuki, Satoshi*; Ogita, Yasuhiro; Yagi, Koshi*; Imura, Takumi*; Motai, Satoko*; Ono, Takeshi*
Lithos, 440-441, p.107026_1 - 107026_14, 2023/03
Times Cited Count:0 Percentile:0.02(Geochemistry & Geophysics)We propose a new method for elucidating zircon growth in granitic plutons, based on variations in three-dimensional 3D cathodoluminescence (CL) patterns, U-Pb ages, titanium concentration, and Th/U ratios. We focused on the zircon growth processes in the Okueyama granite (OKG) in central Kyushu, Japan, to obtain interpretations of magma chamber processes that result in the formation of granitic plutons. The OKG consists of three lithofacies: biotite granite (BG), hornblende granite (HG), and hornblende granodiorite (HGD). To determine the 3D internal structure and growth pattern of a zircon crystal, we performed CL observations for multi-sections of the samples. Simultaneously, we also determined the zircon U-Pb age and titanium concentration of the center sections of the samples. The 3D distribution of the oscillatory zoning can be used to determine the crystal nucleus. The simultaneous determination of zircon U-Pb ages and Ti concentrations of the granite samples indicates the time-temperature (t-T) history of granitic magma before its solidification. The t-T histories of the BG, HG, and HGD represented similar cooling behaviors within the magma chamber: rapid cooling from the zircon crystallization temperature to the closure temperature of the biotite K-Ar system between 16 Ma and 10 Ma. The variations in the Th/U ratios against temperature also demonstrate a different trend at the boundary of approximately 670 C. Fractional crystallization in the magma chamber progressed significantly at temperatures above 670 C; below 670 C, crystallization progressed slowly, indicating only minimal changes in the magma composition. The variations in the Th/U ratio against temperature in the BG, HG, and HGD portrayed common tendencies, indicating the same behavior in the progression of fractional crystallization among the three lithofacies, which in turn, represented the same behavior within the entire magma chamber.
Ohshima, Hiroyuki; Morishita, Masaki*; Aizawa, Kosuke; Ando, Masanori; Ashida, Takashi; Chikazawa, Yoshitaka; Doda, Norihiro; Enuma, Yasuhiro; Ezure, Toshiki; Fukano, Yoshitaka; et al.
Sodium-cooled Fast Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.3, 631 Pages, 2022/07
This book is a collection of the past experience of design, construction, and operation of two reactors, the latest knowledge and technology for SFR designs, and the future prospects of SFR development in Japan. It is intended to provide the perspective and the relevant knowledge to enable readers to become more familiar with SFR technology.
Yuguchi, Takashi*; Yamazaki, Hayato*; Ishibashi, Kozue*; Sakata, Shuhei*; Yokoyama, Tatsunori; Suzuki, Satoshi*; Ogita, Yasuhiro; Sando, Kazusa*; Imura, Takumi*; Ono, Takeshi*
Journal of Asian Earth Sciences, 226, p.105075_1 - 105075_9, 2022/04
Times Cited Count:4 Percentile:49.4(Geosciences, Multidisciplinary)Simultaneous determination of the U-Pb age of zircon and concentration of titanium in a single analysis spot, using inductively coupled plasma mass spectrometry with laser ablation sample introduction, produces paired age and temperature data of zircon crystallisation, potentially revealing time-temperature () histories for evolved magma. The Kurobegawa granite, central Japan, contains abundant mafic magmatic enclaves (MMEs). We applied this method to evaluate MMEs and their host (enclosing) granites. Cooling behaviour common to both MMEs and host rocks was found between 1.5 and 0.5 Ma. Rapid cooling from the zircon crystallisation temperature to the closure temperature of biotite K-Ar system was within 1 million year. Combining the obtained paths of MMEs and host rocks with petrological information can provide insights into magma chamber processes. This suggests that MME flotation, migration, and spread through the magma chamber ceased at 1.5-0.5 Ma, indicating the emplacement age of the Kurobegawa granitic pluton, as no large-scale reheating episodes have occurred since then.
Ueta, Hirokazu; Sasakawa, Yuya*; Ivanov, D.*; Ono, Satoshi*; Ogura, Shohei*; Fukutani, Katsuyuki
Physical Review B, 102(12), p.121407_1 - 121407_5, 2020/09
Times Cited Count:1 Percentile:6.04(Materials Science, Multidisciplinary)Ortho-to-para conversion of molecularly chemisorbed H on a Pd(210) surface at a surface temperature of 50 K is reported. A combination of a pulsed molecular beam, photo-stimulated desorption and resonance-enhanced multiphoton ionization techniques was used for probing the change in the rotational states of molecularly chemisorbed H on the surface. Our result shows that fast ortho-para conversion of chemisorbed H occurs. The conversion time was experimentally determined to be about 2 s, which is in good agreement with a previous theoretical calculation. This agreement supports that the ortho-para conversion mechanism of the molecularly chemisorbed H on Pd(210) is the two-step process based on the hyperfine-Coulomb excitation.
Nakashima, Yosuke*; Takeda, Hisahito*; Ichimura, Kazuya*; Hosoi, Katsuhiro*; Oki, Kensuke*; Sakamoto, Mizuki*; Hirata, Mafumi*; Ichimura, Makoto*; Ikezoe, Ryuya*; Imai, Tsuyoshi*; et al.
Journal of Nuclear Materials, 463, p.537 - 540, 2015/08
Times Cited Count:19 Percentile:82.55(Materials Science, Multidisciplinary)Asakura, Nobuyuki; Hoshino, Kazuo; Shimizu, Katsuhiro; Shinya, Kichiro*; Uto, Hiroyasu; Tokunaga, Shinsuke; Tobita, Kenji; Ono, Noriyasu*
Journal of Nuclear Materials, 463, p.1238 - 1242, 2015/08
Times Cited Count:12 Percentile:70.51(Materials Science, Multidisciplinary)Arrangements of interlink divertor coils and divertor geometries for short super-X was proposed as the Demo advanced divertor design. Performance of plasma detachment under the large heat flux was investigated to optimize the divertor design, using SONIC simulation with Ar impurity seeding, where Pout = 500 MW, ne = 710 m at the core-edge boundary and the same diffusion coefficients for ITER simulation. Effects on the plasma temperature and density distributions were compared to the conventional divertor. The first run results with the same radiation power fraction of 0.92 in the conventional divertor showed that full detached plasma is produced, the maximum radiation region was maintained upstream the divertor target, and both the plasma heat load plus radiation load at the target was reduced to 10 MWmm level. Simulation for the lower radiation power fractions of 0.8-0.9 was also performed, and physics issues of the short super-X divertor are discussed.
Nakashima, Yosuke*; Sakamoto, Mizuki*; Yoshikawa, Masayuki*; Oki, Kensuke*; Takeda, Hisahito*; Ichimura, Kazuya*; Hosoi, Katsuhiro*; Hirata, Mafumi*; Ichimura, Makoto*; Ikezoe, Ryuya*; et al.
Proceedings of 25th IAEA Fusion Energy Conference (FEC 2014) (CD-ROM), 8 Pages, 2014/10
Sakamoto, Mizuki*; Ono, Noriyasu*; Asakura, Nobuyuki; Hoshino, Kazuo
Purazuma, Kaku Yugo Gakkai-Shi, 90(8), p.473 - 479, 2014/08
no abstracts in English
Abe, Sosuke*; Ono, Shinya*; Kanemura, Rui*; Yoshigoe, Akitaka; Teraoka, Yuden; Ogata, Shoichi*; Yasuda, Tetsuji*; Tanaka, Masatoshi*
Applied Physics Express, 6(11), p.115701_1 - 115701_4, 2013/11
Times Cited Count:4 Percentile:18.35(Physics, Applied)Kawakami, Sho*; Shibata, Yoshihide; Watanabe, Kiyomasa*; Ono, Noriyasu*; Isayama, Akihiko; Takizuka, Tomonori*; Kawano, Yasunori; Okamoto, Masaaki*
Physics of Plasmas, 20(11), p.112507_1 - 112507_6, 2013/11
Times Cited Count:2 Percentile:8.92(Physics, Fluids & Plasmas)According to an early work on the behavior of the plasma current decay in the JT-60U disruptive discharges caused by the radiative collapse with a massive neon-gas-puff, the increase of the internal inductance mainly determined the current decay time of plasma current during the initial phase of current quench. To investigate what determines the increase of the internal inductance, we focus attention on the relationship between the electron temperature (or the resistivity) profile and the time evolution of the current density profile, and carry out numerical calculations. As a result, we find the reason of the increase of the internal inductance: The current density profile at the start of the current quench is broader than an expected current density profile in the steady state, which is determined by the temperature (or resistivity) profile. The current density profile evolves into peaked one and the internal inductance is increasing.
Asakura, Nobuyuki; Shinya, Kichiro*; Tobita, Kenji; Hoshino, Kazuo; Shimizu, Katsuhiro; Uto, Hiroyasu; Someya, Yoji; Nakamura, Makoto; Ono, Noriyasu*; Kobayashi, Masahiro*; et al.
Fusion Science and Technology, 63(1T), p.70 - 75, 2013/05
no abstracts in English
Asakura, Nobuyuki; Shinya, Kichiro*; Tobita, Kenji; Hoshino, Kazuo; Shimizu, Katsuhiro; Uto, Hiroyasu; Someya, Yoji; Nakamura, Makoto; Ono, Noriyasu*; Kobayashi, Masahiro*; et al.
Fusion Science and Technology, 63(1T), p.70 - 75, 2013/05
Times Cited Count:14 Percentile:72.14(Nuclear Science & Technology)Design study of poloidal field coil (PFC) locations and current distribution for the advanced divertor in the Demo tokamak reactor was presented. Concept of the super-X divertor (SXD) for Demo reactor has an outer divertor leg longer than the conventional divertor, and it extends outboard to increase both the target wetted area and connection length to the outer target (). Equilibrium calculation code, TOSCA, was developed by introducing two parameters, i.e. super-X null radius () and a ratio of the poloidal flux at the super-X null to that at the separatrix (). Some SXD magnetic configurations with minimal number of PFCs located outside toroidal field coil (TFC) were Demonstrated. Locations of the divertor target were also investigated. It was found that the flux expansion can be increased up to 4-10 depending on the target location and , and that SXD has an advantage to increase with . Thus, the divertor plasma temperature is expected to decrease at the same upstream plasma density. On the other hand, large currents for the divertor PFCs were necessary. Other arrangements of PFCs such as (1) larger and (2) inside TFC, can reduce the PFC currents.
Ono, Shinya*; Inoue, Kei*; Morimoto, Masahiro*; Arae, Sadanori*; Toyoshima, Hiroaki*; Yoshigoe, Akitaka; Teraoka, Yuden; Ogata, Shoichi*; Yasuda, Tetsuji*; Tanaka, Masatoshi*
Surface Science, 606(21-22), p.1685 - 1692, 2012/11
Times Cited Count:8 Percentile:35.38(Chemistry, Physical)Kajita, Shin*; Hatae, Takaki; Sakuma, Takeshi; Takamura, Shuichi*; Ono, Noriyasu*; Itami, Kiyoshi
Plasma and Fusion Research (Internet), 7(Sp.1), p.2405121_1 - 2405121_4, 2012/09
Toyoshima, Hiroaki*; Hiraga, Kenta*; Ono, Shinya*; Tanaka, Masatoshi*; Ozawa, Kenichi*; Mase, Kazuhiko*; Hirao, Norie; Sekiguchi, Tetsuhiro; Shimoyama, Iwao; Baba, Yuji
Photon Factory Activity Report 2011, Part B, P. 102, 2012/00
The knowledge of the interaction between organic molecules and semiconductor surfaces plays an important role in adapting organic semiconductors into the semiconductor technology. In the present study, the process of -sexithiophene (-6T) thin layer formation on passivated silicon (Si) surfaces has been investigated in-situ by means of PES, angle-depended NEXAFS (near-edge X-ray absorption fine-structure), SDRS, and RDS. For water-adsorbed Si(001), it was found that the majority of -6T molecules are standing on the substrate. Above 3 nm, most of molecules are standing and constitute well ordered islands or films. For ethylene adsorbed Si(001) on the contrary, some of -6T molecules are flat-lying, resulting in less prominent orientation. Thus, the orientation of molecules depends on the method of passivation, which opens the possibility of controlling the molecular orientation by the surface modification.
Shibata, Yoshihide*; Watanabe, Kiyomasa*; Ono, Noriyasu*; Okamoto, Masaaki*; Isayama, Akihiko; Kurihara, Kenichi; Oyama, Naoyuki; Nakano, Tomohide; Kawano, Yasunori; Matsunaga, Go; et al.
Plasma and Fusion Research (Internet), 6, p.1302136_1 - 1302136_4, 2011/10
no abstracts in English
Tanaka, Yasunori*; Smirnov, R. D.*; Pigarov, A. Y.*; Takenaga, Hidenobu; Asakura, Nobuyuki; Uesugi, Yoshihiko*; Ono, Noriyasu*
Journal of Nuclear Materials, 415(Suppl.1), p.S1106 - S1110, 2011/08
Times Cited Count:10 Percentile:57.01(Materials Science, Multidisciplinary)Dust can be an important contributor to impurity contamination of the core and scrape-off-layer (SOL) plasmas in tokamak fusion devices. This is the first report about investigation of transport of carbon dust particles in case of JT-60U tokamak using the dust transport code (DUSTT). The DUSTT code takes into account various plasma-dust interaction processes. In the present report, background plasma parameters in JT-60U such as densities and temperatures of electron, ion and neutral atom were computed with the UEDGE code. Three dimensional trajectories, temperature evolution, and radius variation of dust particles launched from different positions at the inner divertor, the outer divertor and the dome structure in JT-60U tokamak were simulated numerically to study dynamics and transport of dust particles there. As a result, the lifetime of dust particles is dependent mainly on the ion density in trajectories in final term.
Asakura, Nobuyuki; Ashikawa, Naoko*; Ueda, Yoshio*; Ono, Noriyasu*; Tanabe, Tetsuo*; Nakano, Tomohide; Masuzaki, Suguru*; Itami, Kiyoshi; Kawano, Yasunori; Kawahata, Kazuo*; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 87(7), p.485 - 486, 2011/07
no abstracts in English
Ono, Shinya*; Inoue, Kei*; Morimoto, Masahiro*; Arae, Sadanori*; Toyoshima, Hiroaki*; Yoshigoe, Akitaka; Teraoka, Yuden; Ogata, Shoichi*; Yasuda, Tetsuji*; Tanaka, Masatoshi*
Shingaku Giho, 111(114), p.23 - 27, 2011/07
The initial oxidation on high-index silicon surfaces with (113) and (120) orientations at 820 K has been investigated by real-time X-ray photoemission spectroscopy (Si 2p and O 1s) using 687 eV photons. The time evolutions of the Si (n=1-4) components in the Si 2p spectrum indicate that the Si state is suppressed on high-index surfaces compared with Si(001). The O 1s state consists of two components, a low-binding-energy component (LBC) and a high-binding-energy component (HBC). It is suggested that the O atom in strained Si-O-Si contributes to the LBC component. The reaction rates are slower on high-index surfaces compared with that on Si(001).
Kajita, Shin*; Hatae, Takaki; Itami, Kiyoshi; Ono, Noriyasu*; Nakano, Tomohide
Journal of Plasma and Fusion Research SERIES, Vol.9, p.157 - 162, 2010/08