Observation of nonreciprocal diffraction of surface acoustic wave

新居 陽一*; 山本 慧; 菅野 将誠*; 前川 禎通*; 小野瀬 佳文*

Physical Review Letters, 134(2), p.027001_1 - 027001_5, 2025/01

https://doi.org/10.1103/PhysRevLett.134.027001

While the rectification phenomenon caused by the simultaneous breaking of time reversal and spatial inversion symmetries has been extended to a wide range of (quasi)particles and waves, the nonreciprocal diffraction, which is the imbalance of upward and downward deflections, was previously observed only for photons and remained to be extended to other (quasi)particles. Here, we present evidence of the nonreciprocal diffraction of surface acoustic wave (SAW) utilizing a magnetoelastic grating on a SAW device. Asymmetric diffraction intensities were observed when the ferromagnetic resonance was acoustically excited. Based on a theoretical model, we ascribe the microscopic origin of this phenomenon to the resonant scattering involving ferromagnetic resonance excitations. The novel property may pave an avenue to further development of SAW devices for various purposes including microwave communications and quantum engineering applications.

Research and development of three-dimensional isolation system for sodium-cooled fast reactor, 8; Assembly static test results of three-dimensional isolated device by bi-axial loadings

杣木 孝裕*; 湯川 正貴*; 深沢 剛司*; 平山 智之*; 内田 昌人*; 宮川 高行; 岡村 茂樹; 山本 智彦; 渡壁 智祥; 宮崎 真之; et al.

Proceedings of the ASME 2024 Pressure Vessels & Piping Conference (PVP 2024) (Internet), 9 Pages, 2024/07

https://doi.org/10.1115/PVP2024-124495

The authors have been developing the three-dimensional isolation system for the Sodium-cooled Fast Reactor. The three-dimensional isolation device consists of the laminated rubber bearing performing the horizontal isolation function, four-disc spring units, the sliding function, strength members such as the horizontal support function, and dampers in the horizontal and vertical directions. We carried out the half-scaled integrated seismic tests under several bi-axial severe conditions from design base loads to significantly exceeding design base loads. The test specimen was assembled elements consisting of Three-Dimensional Seismic Isolation System, but the horizontal and vertical damping devices were not modeled because of the static tests. We report tests results, focusing on the following items. Behavior of smooth operation and ensuring the independency of horizontal isolation and vertical isolation performances. Hypothesis and verification of load transfer mechanism under horizontal and vertical loads superposition. Effect of reinforcing plates on the loading force reduction of horizontal support function. Conditions of the specimen after tests and discussion.

Contributions of multimodal microstructure in the deformation behavior of extruded Mg alloys containing LPSO phase

萩原 幸司*; 眞山 剛*; 山崎 倫昭*; Harjo, S.; 徳永 透子*; 山本 和輝*; 杉田 三佳*; 青山 海琳*; Gong, W.; 西本 宗矢*

International Journal of Plasticity, 173, p.103865_1 - 103865_21, 2024/02

https://doi.org/10.1016/j.ijplas.2023.103865

The unique control mechanisms of the plastic deformation of two-phase extruded alloy composed of Mg and long-period stacking ordered (LPSO) phase were clarified by comparison with those of other Mg solid-solution alloys, focusing on the question of why do the Mg/LPSO two-phase alloys exhibit both large elongation and high strength? The stress-strain curves for each grain in the alloys could be imaginary estimated using neutron diffraction analysis during the tensile test. The results demonstrate that the deformation behaviors of the worked and recrystallized grains are significantly different in all the Mg-extruded alloys owing to the strong plastic anisotropy in Mg with hexagonal close-packed (hcp) structure. Therefore, the deformation behavior is controlled by a composite-like deformation mechanism, even in single-phase Mg solid-solution alloys.

Urban factors and mental health symptoms in children of the Tokyo Early Adolescence Survey; Impact of proximity to railway stations

Davies, S. J. C.*; Bolea-Alamanac, B.*; 遠藤 香織*; 山本 優*; 山崎 修道*; Malins, A.; Evans, J.*; Sullivan, S.*; 安藤 俊太郎*; 西田 淳志*; et al.

Journal of Transport & Health, 28, p.101564_1 - 101564_11, 2023/01

https://doi.org/10.1016/j.jth.2022.101564

The study tested the hypothesis that proximity of home to railway stations is a positive predictor of mental health at age 10 years. Using the Tokyo Early Adolescence Survey we examined relationships between distance from home to the nearest railway station and SDQ (Strengths and Difficulties Questionnaire) scores for hyperactivity/inattention, prosocial behaviour and emotional symptoms. Greater distance to the nearest railway station was associated with SDQ-derived hyperactivity/inattention scores in the unadjusted analysis across all 4052 analyzable children, and in the fully adjusted analysis in boys ( = 0.198, 95% C.I. 0.009 to 0.386, p = 0.040) but not in girls ( = 0.007, 95% C.I. -0.164 to 0.177, p = 0.940). There were no associations with other SDQ-based outcomes. If replicated, these findings suggest that access to high-quality transit may be associated with improved hyperactivity/inattention outcomes in children living in urban environments.

An Automotive intelligent catalyst that contributes to hydrogen safety for the Decommissioning of Fukushima Daiichi Nuclear Power Station (1FD)

田中 裕久*; 正木 清香*; 青谷 拓朗*; 稲川 康平*; 岩田 宗悟*; 相田 樹哉*; 山本 忠亮*; 喜多 知輝*; 大野 瞳*; 竹中 啓恭*; et al.

SAE Technical Paper 2022-01-0534 (Internet), 10 Pages, 2022/03

https://doi.org/10.4271/2022-01-0534

The catalyst called a Passive Autocatalytic Recombiner (PAR) is required to have robustness that can maintain its activity for more than 30 years in an environment where temperature, humidity, gas concentration, etc. cannot be controlled. Here, it is expected that "An Intelligent Catalyst" for automotive emissions control exhibits excellent performance even in such a harsh environment. The intelligent catalyst is the nanostructure designed perovskite catalyst that has the rejuvenating function instead of preventing aging. The authors emphasize that the technology developed as a catalyst for automobiles is expected to be useful not only in other industries but also as a relief technology from the national crisis.

Summary of temporal changes in air dose rates and radionuclide deposition densities in the 80 km zone over five years after the Fukushima Nuclear Power Plant accident

斎藤 公明; 三上 智; 安藤 真樹; 松田 規宏; 木名瀬 栄; 津田 修一; 吉田 忠義; 佐藤 哲朗*; 関 暁之; 山本 英明*; et al.

Journal of Environmental Radioactivity, 210, p.105878_1 - 105878_12, 2019/12

https://doi.org/10.1016/j.jenvrad.2018.12.020

We summarized temporal changes in air dose rates and radionuclide deposition densities over five years in the 80 km zone based on large-scale environmental monitoring data obtained continuously after the Fukushima Nuclear Power Plant (NPP) accident. The air dose rates in environments associated with human lives decreased at a considerably faster rate than expected for radioactive decay. The average air dose rate originating from the radiocesium deposited in the 80 km zone was lower than that predicted from radioactive decay by a factor of 2-3 at five years after the accident. The causes of this rapid reduction were discussed quantitatively considering the characteristics of radiocesium migration in the environment.

Measurement of ambient dose equivalent rates by walk survey around Fukushima Dai-ichi Nuclear Power Plant using KURAMA-II until 2016

安藤 真樹; 山本 英明*; 菅野 隆*; 斎藤 公明

Journal of Environmental Radioactivity, 190-191, p.111 - 121, 2018/10

https://doi.org/10.1016/j.jenvrad.2018.04.025

福島第一原子力発電所から80km圏内での2013年から2016年までのKURAMA-IIを用いた歩行サーベイにより、生活環境での空間線量率が測定された。歩行サーベイ測定地点では42ヶ月間に38%にまで線量率が低下した。放射性セシウムの物理半減期による線量率の減少は55%に比べて明らかに早い減少となった。避難指示区域の区分ごとに空間線量率減少を調べた結果、人間生活の活発な地域において減少速度がより早いことが分かった。歩行サーベイにより測定した空間線量率は走行サーベイによる測定結果とよい相関を示しており、道路上の走行サーベイ結果は歩行サーベイによる道路周辺での空間線量率を反映したものとなっている。また、走行サーベイでの100m四方において、歩行サーベイによる空間線量率は大きく変化していることが分かった。歩行サーベイによる測定結果は、走行サーベイと攪乱のない平坦地上での測定結果の中間に位置した。歩行サーベイによる空間線量率は平坦地上での測定結果に比べて減少が早いことが分かった。

Observation of momentum-dependent charge excitations in hole-doped cuprates using resonant inelastic X-ray scattering at the oxygen edge

石井 賢司*; 遠山 貴巳*; 浅野 駿*; 佐藤 研太朗*; 藤田 全基*; 脇本 秀一; 筒井 健二*; 曽田 繁利*; 宮脇 淳*; 丹羽 秀治*; et al.

Physical Review B, 96(11), p.115148_1 - 115148_8, 2017/09

AA2017-0402.pdf:0.81MB

https://doi.org/10.1103/PhysRevB.96.115148

We investigate electronic excitations in La(Br,Sr)CuO using resonant inelastic X-ray scattering (RIXS) at the oxygen edge. We observed momentum-dependent spectral weight below 1 eV, which is consistent with theoretical calculation of the dynamical charge structure factor on oxygen orbitals in a three-band Hubbard model. Our results confirm that the momentum-dependent charge excitations exist on the order of the transfer energy (), and the broad spectral line shape indicates damped and incoherent character of the charge excitations at the energy range in the doped Mott insulators.

Development of instrumentation and control systems for the ITER diagnostic systems in JADA

山本 剛史; 橋本 慰登*; 北澤 真一; 谷塚 英一; 波多江 仰紀; 杉江 達夫; 小川 宏明; 竹内 正樹; 河野 康則; 伊丹 潔

Fusion Engineering and Design, 96-97, p.1012 - 1016, 2015/10

https://doi.org/10.1016/j.fusengdes.2015.06.119

日本国内機関では、ITER計画において6種類のプラズマ計測装置の調達を担当している。原子力機構では、ITER標準ソフトウェアを用いて、統括制御機能、シーケンス制御管理機能及びデータ収集機能を含むITER計測装置用計装制御システムを開発した。統括制御機能は、センサーの健全性検査、計測条件の設定及び計測条件間の一貫性検査といった計測のための内部処理を管理する。我々は、Python言語を用いてフローチャートからEPICS(Experimental Physics and Industrial Control System)のコードを生成するツール及びシーケンス制御管理機能を開発した。EPICSは、運転手順のトリガー及び進行を示すために使用される。シーケンス制御管理機能は、EPICSを用いてプラント状態の変化を監視することにより、運転手順の進行を管理する。EPICSと運転手順の関連付けは、上記ツールにより自動的に行われる。我々は、熱電対計測システムに関して、上記の計装制御システムの性能を検証した。また、さらに複雑な計測装置向けに本設計を適用していく予定である。

Development on rubber bearings for sodium-cooled fast reactor, 2; Fundamental characteristics of half-scale rubber bearings based on static test

深沢 剛司*; 岡村 茂樹*; 山本 智彦; 川崎 信史; 杣木 孝裕*; 櫻井 祐*; 正木 信男*

Proceedings of 2015 ASME Pressure Vessels and Piping Conference (PVP 2015) (Internet), 10 Pages, 2015/07

Na冷却高速炉は薄肉構造であり地震力を低減するために、免震システムを採用している。SFRに適用する免震装置は、ゴム層を厚くした積層ゴムが用いられている。この積層ゴムの水平及び上下方向の剛性及び減衰定数を把握するために、直径800mmのハーフスケールの積層ゴムを用いて、水平方向の線形限界や上下方向の降伏応力を上回る範囲で試験を実施することとし、その結果と考察を報告する。