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Lim, G.-C.*; 福谷 克之; 他8名*
Journal of the American Chemical Society, 146(46), p.32013 - 32021, 2024/11
被引用回数：3 パーセンタイル：51.94(Chemistry, Multidisciplinary)We investigate ultrahigh concentration doping of hydrogen (H) into rutile-TiO(100) single crystals by low-energy (2.5 keV) hydrogen ion beam irradiation at low temperature (LT). While the hydrogen concentration was limited to H
TiO at 300 K, in situ nuclear reaction analysis (NRA) revealed ultrahigh concentration doping of hydrogen up to H
TiO by the LT irradiation at 50 K. The large (
8.2%) expansion of the out-of-plane lattice constant suggests that hydrogen occupies interstitial sites in rutile TiO. Hydrogens of early stage irradiation act as electron donors and induce a large increase in conductivity, which is consistent with theoretical studies in the dilute limit. The nature of excess H was investigated in situ by transport and photoemission measurements. After LT excess H doping and postannealing to room temperature, unusual electrical transport properties were observed while maintaining the ultrahigh H concentration. In situ photoemission measurements show that the excessively doped hydrogens by LT irradiation generate a deeper in-gap state (IGS) of metastable nature. Density functional theory predicts the formation of double neighboring interstitial hydrogens as a possible mechanism for the deeper IGS.
Cf fission fragments with MRTOF-MS and detailed study of masses of neutron-rich Ce isotopes木村 創大*; 伊藤 由太; 他8名*
Physical Review C, 110(4), p.045810_1 - 045810_9, 2024/10
被引用回数：2 パーセンタイル：74.11(Physics, Nuclear)We report the mass measurements of neutron-rich isotopes produced via spontaneous fission of Cf using a multireflection time-of-flight mass spectrograph. The mass of 
Ce is determined experimentally for the first time. A discrepancy between the experimental and literature values was found for the mass of 
Sb, which was previously deduced through indirect measurements. In comparison with several theoretical predictions, both the values and the trend of the mass excesses of 
Ce cannot be consistently explained. The wide-range and simultaneous mass measurements of the multireflection time-of-flight mass spectrograph enable us to crosscheck the existing mass data, and the conflict between the measured time-of-flight ratio and the extracted mass would imply the necessity of re-examining them.
船引 雄太*; 伊與田 宗慶*; 菖蒲 敬久; 松田 朋己*; 林 雄二郎*; 佐野 智一*; 他8名*
Journal of Manufacturing Processes, 115, p.40 - 55, 2024/04
被引用回数：4 パーセンタイル：78.76(Engineering, Manufacturing)In resistance spot welding (RSW) of Fe and Al alloy, an intermetallic compound (IMC) is formed at the joining interface, and it is known that the joining strength of the joint decreases as the IMC becomes thicker. In this study, the convection behavior in the Al alloy melting zone of an Fe-Al alloy RSW was varied and the effect on the joint characteristics was investigated. For this study, focusing on the electromagnetic force generated in the Al alloy melting zone, the convection behavior in the Al alloy melting zone was changed by adding an external magnetic field using neodymium magnets. In-situ evaluation of the convection behavior using synchrotron radiation and cross-sectional macro-observation of the joint revealed that the addition of an external magnetic field causes a non-axisymmetric change in the convection behavior in the Al alloy melting zone, which results in the deflection of the Al alloy melting zone. The addition of an external magnetic field increases the driving force of convection and homogenizes the temperature field at the joining interface, suggesting that the IMC near the center is formed thin and uniform. Furthermore, from the cross tension test and the observation of the fracture surface of the joint after the test, it was clarified that the CTS of the joint with an external magnetic field was improved by the propagation of cracks into the Al alloy melting zone during the test.
Zhang, X.*; Gong, W.; 他8名*
International Journal of Plasticity, 173, p.103896_1 - 103896_24, 2024/02
被引用回数：22 パーセンタイル：99.08(Engineering, Mechanical)The distribution and partitioning of solute atoms in age-hardenable aluminum (Al) alloys markedly impact strength, ductility and failure of alloy materials, thus rendering the understanding of dislocation-obstacle (solute-rich features) interactions crucial in the development of a new class of heat-treatable Al alloys. Here, we investigate the slip mechanisms, strain localization and strain hardening of a high Mg-content lightweight AlMgZn-based crossover alloy aged to different conditions with the focus on the dislocation-obstacle interactions. It is found that due to different elemental partitioning between matrix and solute-rich features the interaction of dislocations with obstacles can be drastically different for samples with varying precipitates. The dislocations in the under-aged and near peak-aged samples show predominantly planar slip, which produces strain localization. Whereas in the over-aged sample, gliding dislocations initially bend between adjacent precipitates lying in the slip planes, and subsequently surmount them by local cross slip processes, giving rise to homogeneous slip. It is discovered that strain localization in the form of coarse slip bands induces strain hardening in the under-aged material. To understand the enhanced strain hardening observed in the under-aged sample, four key influencing factors are proposed. In addition, the predicted yield strengths for the solution-treated and artificially aged materials match well with those experimentally measured values.
Mao, W.*; 福谷 克之; 他8名*
International Journal of Hydrogen Energy, 50(Part D), p.969 - 978, 2024/01
被引用回数：5 パーセンタイル：39.43(Chemistry, Physical)Cerium oxide (CeO) is well known to be reducible by hydrogen (H), yet the diffusion and solution properties of hydrogen in ceria at elevated temperatures have remained challenging to evaluate. We therefore fabricated nanometer-thin (100 nm) cerium oxide films on Si(111) substrates by pulsed laser deposition (PLD) and quantitatively investigated the H depth distributions therein by means of resonant 
H(
N,
)
C nuclear reaction analysis (NRA) before and after annealing in H gas at 773-973 K. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS) reveal that the as-deposited films exhibit single phase CeO structure and partially reduced stoichiometry (CeO
). H annealing does not largely change the H content of the as-deposited films; in all conditions several atomic percent of hydroxyl (OH) are found to exist in a thin (4 nm) surface layer, whereas stably bound hydrogen in the bulk of the films is almost uniformly distributed and of much smaller quantity (0.2 at.%) than the oxygen vacancy concentration in the partially reduced ceria. Its low concentration and high thermal stability identify this bulk H species as likely being strongly bound to defects in the polycrystalline films rather than as a hydride species that interacts weakly with O-vacancies. The H diffusion coefficient and activation energy in the ceria films are determined as 
10
m
s
at 773-973 K and 
1.69 eV, respectively. The observed diffusion activation energy is somewhat larger than theoretical predictions for thermal diffusion of H in stoichiometric bulk CeO, suggesting that defects and oxygen vacancies in the PLD-fabricated ceria thin films possibly have an impact on the H mobility.
S-nuclear magnetic resonance measurements吉田 章吾*; 芳賀 芳範; 藤井 拓斗*; 中井 祐介*; 水戸 毅*; 他8名*
Journal of the Physical Society of Japan, 93(1), p.013702_1 - 013702_5, 2024/01
被引用回数：0 パーセンタイル：0.00(Physics, Multidisciplinary)In Kondo insulators, a small energy gap evolves only at low temperatures. In this study, S-nuclear magnetic resonance measurements under high pressures are performed to clarify the electronic structure of SmS. The spin-lattice relaxation time, consisting of multiple components, was analyzed based on a periodic Anderson model with Bayesian inference, leading to a peculiar small gap state arising from strong hybridization.
NH and CaNH thin films by reactive magnetron sputtering under hydrogen partial pressure controlChon, S.*; 福谷 克之; 他8名*
Journal of Physical Chemistry Letters (Internet), 13(43), p.10169 - 10174, 2022/11
被引用回数：0 パーセンタイル：0.00(Chemistry, Physical)Calcium compounds with N and H are promising catalysts for NH
conversion, and their epitaxial thin films provide a platform to quantitatively understand the catalytic activities. Here we report the selective epitaxial growth of CaNH and CaNH thin films by controlling the hydrogen partial pressure (
) during reactive magnetron sputtering. We find that the hydrogen charge states can be tuned by : CaNH containing H
is formed at 
Pa, while CaNH containing H
is formed at 
Pa. In situ plasma emission spectroscopy reveals that the intensity of the Ca atomic emission (422 nm) decreases as increases, suggesting that Ca reacts with H and N to form CaNH at lower , whereas at higher , CaH
is first formed on the target surface and then sputtered to produce CaNH. This study provides a novel route to control the hydrogen charge states in Ca-N-H epitaxial thin films.
Pant, A. D.*; 髭本 亘; 三宅 康博; 他8名*
Nuclear Instruments and Methods in Physics Research A, 929, p.129 - 133, 2019/06
被引用回数：6 パーセンタイル：47.17(Instruments & Instrumentation)J-PARCにおいて超低速ミュオン顕微鏡の開発を行っている。モンテカルロシミュレーションを行った結果、これまでに試料位置での漏れ磁場の影響があることが示されていた。この影響を最小化するために、四重極電場のバランスを崩したチューニングを行った。これによるビーム輸送に関して、実験エリアU1Aにおけるビームサイズ、時間およびエネルギー分解能等に関しての特性調査と最適化を報告した。
匂坂 明人; 大道 博行; Pirozhkov, A. S.; 森 道昭; 余語 覚文; 小倉 浩一; 織茂 聡; 西内 満美子; Ma, J.-L.; 桐山 博光; et al.
Frontiers of Optoelectronics in China, 2(3), p.299 - 303, 2009/09
高強度レーザーと薄膜との相互作用により、高エネルギーのイオンや電子,硬X線,高次高調波,テラヘルツ(THz)波などが発生する。高強度チタンサファイアレーザーを用いて、薄膜ターゲットへの照射実験を行った。薄膜ターゲットから発生する陽子線とテラヘルツ波の同時発生を計測した。また、陽子線と紫外高調波についても同時発生を計測した。
川崎 昇*; 中村 孝久*; 北端 琢也*; 他8名*
PNC TN3410 89-011, 617 Pages, 1989/07
新型転換炉ふげん発電所(以下「ふげん」と略す)では、運開当時、既に先行軽水炉の状況から、運転経過とともに原子炉冷却系の機器・配管に放射性腐食生成物(以下「クラッド」と略す)が蓄積し、線量当量率の上昇が予測された。そのため系統の化学除染(以下「系統除線」と略す)がいずれ必要になることも考慮して、情報の収集に当り、昭和55年に国内外の化学除染技術の公開情報をまとめ、「ふげん」に最適な除染剤について選定・評価してきた。除染剤の選定・評価するための検討項目は、除染性能、構成材健全性への影響、廃液処理性、施工性等種々あるが、できる限りの検討を加え、最終的に国産品の希薄液除染剤であるクリデコン203を選定した。選定以後、約8年をかけて上記項目に対するクリデコン203の基礎データを確認するとともに、実機熱交換器等の除染実証試験を行い、系統除染への適用の見通しを得た。一方、平成元年7月中旬より実施する「ふげん」の第8回定期検査では、原子炉再循環ポンプの分解点検、応力腐食割れ(以下「SCC」と略す)予防対策のための原子炉再循環系下部へッダ部分取替工事等、原子炉建屋内高線量当量率下での作業を計画している。これらの作業を含めた定期検査時の総線量当量は、これまで以上に増大することが予測され、効果的な被ばく低減策の実施が必要な状況にあることから、第8回定期検査時には、2系統ある原子炉冷却系統のうち主要な点検・工事の対象となるA側の片ループについて系統除染を行い、作業被ばくの低減化を図る計画を立てた。この系統除染を実施するに当り、動燃事業団は、科学技術庁に対し系統除染計画の説明を行い、当該計画の妥当性の確認を行った。これに対し、科学技術庁原子炉安全局原子炉規制課は、化学除染、金属材料、金属腐食・水化学等の専門家からなる「原子炉安全技術顧問ふげん発電所化学除染ワーキンググループ」(以下「顧問会」という)を3回開催し、除染の有効性、材料健全性、除染作業の安全性、材料健全性確認追跡調査の妥当性等について諮問を行った。その結果、「ふげん」の系統除染計画の妥当性は確認され、当該計画は了承された。本資料は、動燃事業団がこれまで行ってきた「ふげん」の系統除染に係る研究開発結果及び系統除染計画検討結果を上記顧問会用資料として新たにまとめたものである。また、合わせて上記顧問会における質問事項の回答資料等を添付
