※ 半角英数字
 年 ~ 
検索結果: 63 件中 1件目~20件目を表示


Initialising ...



Initialising ...


Initialising ...


Initialising ...


Initialising ...


Initialising ...


Initialising ...


Initialising ...




淵田 知希*; 浦田 泰成*; 松山 嗣史*; 村上 昌史; 吉田 幸彦; 植田 昭彦; 町田 昌彦; 佐々木 紀樹; 辻 幸一*

X線分析の進歩,53, p.77 - 87, 2022/03

蛍光X線(XRF: X-ray fluorescence)分析法はX線を試料に照射し、発生した蛍光X線を検出することで試料の元素分析を行う手法である。試料を走査しながら連続的なXRF分析を行うことで、二次元の元素分布像の取得が可能である。本研究では、ベルトコンベア上を連続的に移動する試料に対して、二次元の元素分布像を迅速に取得するためのXRF分析装置を開発した。元素分布像の測定は、X線を広範囲に照射したベルトコンベアを横切る方向に、コリメーターを取り付けた検出器を走査することにより実施し、この方法における試料や検出器の移動方向の空間分解能や検出限界を検証した。また、2種類の金属試料について同時に元素分布像を測定し、開発した装置により多元素同時イメージングが実施できることを実証した。


Numerical experiment for processing noisy magnetotelluric data based on independence of signal sources and continuity of response functions

小川 大輝; 浅森 浩一; 上田 匠*

Proceedings of 14th SEGJ International Symposium, p.51 - 54, 2021/11

In the magnetotelluric (MT) method, observed data consist of the sum of several types of signals. The technique of blind source separation (BSS) has been utilized to suppress the effect of artificial noises on MT response functions. When reconstructing the noise-reduced observed data by means of BSS, it is crucial to eliminate the specific components which correspond to noise. Yet improper subtraction of values from separated signals can lead to the loss of useful values of the natural signal or missing a large amount of noise-affected values, which may result in failure in deriving the true MT responses. This study proposes a novel algorithm that utilizes frequency-domain independent component analysis (FDICA). The observed data were classified into the XY and YX modes and the components of the reference magnetic field were appended to respective modes so that both the assumed source signal and the mixed signal have same number of components. The MT response functions, which are represented as the ratio of horizontal electric to magnetic field components, are substantially constant over the relatively short period of time. Moreover, the MT response functions vary smoothly in the frequency domain. An evaluation index with respect to these two characteristics of the natural signal was introduced when determining which values to subtract prior to the reconstruction of the observed data. We verify the performance of noise suppression by applying the proposed method to a set of MT time series affected by synthetic strong noise over the whole observation time.


Nonmagnetic-magnetic transition and magnetically ordered structure in SmS

吉田 章吾*; 小山 岳秀*; 山田 陽彦*; 中井 祐介*; 上田 光一*; 水戸 毅*; 北川 健太郎*; 芳賀 芳範

Physical Review B, 103(15), p.155153_1 - 155153_5, 2021/04

 被引用回数:0 パーセンタイル:0(Materials Science, Multidisciplinary)

SmS, a protopypical intermediate valence compound, has been studied by performing high-pressure nuclear magnetic resonance measurements. The observation of an additional signal at high pressure gives evidence of a magnetic phase transition. The cancellation of the hyperfined fields at the S site suggests a type-II antiferromagnetic structure.


A Consideration on the use of shear waves to improve the sensitivity of an optical ultrasonic sensor for under-sodium viewers

猿田 晃一; 白濱 卓馬*; 山口 智彦; 上田 雅司

E-Journal of Advanced Maintenance (Internet), 10(2), p.1 - 8, 2018/08

The present work is intended to investigate shear waves induced on stainless steel diaphragms by the incidence of ultrasonic waves, with the main emphasis on the understanding of the generation mechanism of the resultant second wave, in order to explore the possible use of the shear waves for improvement of the sensitivity of an optical ultrasonic sensor used for under-sodium viewers. The response of the diaphragms exposed to ultrasonic waves with different pressure profiles is measured by a heterodyne interferometer to examine the location where the shear waves are excited. The generation of the second wave is interpreted on the basis of interference of these shear waves. The effectiveness of the use of the shear waves is demonstrated by an improved sensitivity of 0.26 nm/kPa for a 3-mm-diameter and 5-$$mu$$m-thick diaphragm. This sensitivity is approximately 7 times as high as the sensitivity achieved with the first wave, which is the displacement of the diaphragm caused by directly incident ultrasonic waves.


Effects of metallic diaphragms on sensitivity characteristics of an optical ultrasonic sensor and reduction of interrogation time based on wavelength division multiplexing for under-sodium visual inspection

猿田 晃一; 山口 智彦; 上田 雅司

E-Journal of Advanced Maintenance (Internet), 7(4), p.NT75_1 - NT75_8, 2016/02

We have experimentally examined the effects of the metallic diaphragms on the sensitivity characteristics of an optical ultrasonic sensor and investigated the multiplexed interrogation of the diaphragms based on WDM technique. The experimental results show that the sensitivity can be increased by use of thinner and lighter diaphragms. It has also been found that by taking advantage of the interference of the lamb waves propagating through the diaphragm, the sensitivity can be further enhanced by a factor of approximately 5 to 6 with decreasing diameter. The multiplexed interrogation based on WDM technique has been demonstrated in the case of two wavelengths. From this experimental demonstration, we consider that the interrogation time can be significantly reduced by increasing the number of multiplexed wavelengths.


Effects of metallic diaphragm on sensitivity characteristics of optical ultrasonic sensor for under-sodium inspection

猿田 晃一; 山口 智彦; 上田 雅司

EUR-27790-EN, p.209 - 214, 2016/00

We report the effects of the metallic diaphragm on the sensitivity characteristics of the optical ultrasonic sensor used in under-sodium inspection. The diaphragm is set on the wall of a tank filled with water in place of sodium to have direct contact with water on one side and air on the other side. A heterodyne interferometer is employed to detect the wave on the diaphragm induced by the ultrasonic wave emitted from a piezoelectric transducer placed in the water tank. Two kinds of waves appear on the diaphragm: the first corresponds to the incident ultrasonic wave and the second is surface wave arising from the peripheral of the diaphragm. We found that the first wave increases with decreasing thickness of the diaphragm, while the second wave is dependent on both the thickness and diameter. Moreover the second wave has larger amplitude than the first wave due to interference effect at the center of the diaphragm. This result suggests that the small amplitude of the incident ultrasonic wave can be detected with a higher sensitivity by using the second wave on the diaphragm.


Magnetic and electronic properties of URu$$_2$$Si$$_2$$ revealed by comparison with nonmagnetic references ThRu$$_2$$Si$$_2$$ and LaRu$$_2$$Si$$_2$$

江見 直哉*; 濱端 良輔*; 中山 大将*; 三木 俊宙*; 小山 岳秀*; 上田 光一*; 水戸 毅*; 小堀 洋*; 松本 裕司*; 芳賀 芳範; et al.

Journal of the Physical Society of Japan, 84(6), p.063702_1 - 063702_4, 2015/06

 被引用回数:10 パーセンタイル:64.05(Physics, Multidisciplinary)

NMR/NQR measurements have been carried out on ThRu$$_2$$Si$$_2$$ and LaRu$$_2$$Si$$_2$$ which are the nonmagnetic references of the heavy fermion URu$$_2$$Si$$_2$$. Ru-NQR measurements suggest the relatively close electronic configuration between ThRu$$_2$$Si$$_2$$ and URu$$_2$$Si$$_2$$ at high temperature. However, significant delocalization was observed in URu$$_2$$Si$$_2$$ at low temperatures. Si-NMR experiments on URu$$_2$$Si$$_2$$ revealed Ising-like spin fluctuations in the hidden-order state.


Observation of the partial Fermi surface quenching in the noncentrosymmetric superconductor Mo$$_3$$Al$$_2$$C

小山 岳秀*; 尾崎 穣*; 上田 光一*; 水戸 毅*; 小原 孝夫*; 和氣 剛*; 田畑 吉計*; 道岡 千城*; 吉村 一良*; 鈴木 通人; et al.

Journal of the Physical Society of Japan, 81(Suppl.B), p.SB008_1 - SB008_5, 2012/12

 被引用回数:1 パーセンタイル:11.71(Physics, Multidisciplinary)



Partial gap opening on the Fermi surface of the noncentrosymmetric superconductor Mo$$_3$$Al$$_2$$C

小山 岳秀*; 尾崎 穣*; 上田 光一*; 水戸 毅*; 小原 孝夫*; 和気 剛*; 田畑 吉計*; 道岡 千城*; 吉村 一良*; 鈴木 通人; et al.

Physical Review B, 84(21), p.212501_1 - 212501_4, 2011/12

 被引用回数:9 パーセンタイル:42.37(Materials Science, Multidisciplinary)



Conduction-band electronic states of YbInCu$$_4$$ studied by photoemission and soft X-ray absorption spectroscopies

内海 有希*; 佐藤 仁*; 栗原 秀直*; 間曽 寛之*; 平岡 耕一*; 小島 健一*; 飛松 浩明*; 大河内 拓雄*; 藤森 伸一; 竹田 幸治; et al.

Physical Review B, 84(11), p.115143_1 - 115143_7, 2011/09

 被引用回数:7 パーセンタイル:31.79(Materials Science, Multidisciplinary)

典型的な価数揺動系であるYbInCu$$_4$$の価電子状態を、硬X線内殻光電子分光,軟X線吸収実験、及び軟X線光電子分光の温度依存性の実験から研究した。YbInCu$$_4$$の価数転移について、価電子帯からYb 4$$f$$状態への電荷移動で記述した。


Development of an ISI robot for the fast breeder reactor MONJU primary heat transfer system piping

田川 明広; 上田 雅司; 山下 卓哉; 成澤 正孝*; 芳賀 芳一*

Journal of Nuclear Science and Technology, 48(4), p.504 - 509, 2011/04



Effect of water distributions on performances of JARI standard PEFC by using neutron radiography

村川 英樹*; 植田 忠伸*; 吉田 壮寿*; 杉本 勝美*; 浅野 等*; 竹中 信幸*; 持木 幸一*; 飯倉 寛; 安田 良; 松林 政仁

Nuclear Instruments and Methods in Physics Research A, 605(1-2), p.127 - 130, 2009/06

 被引用回数:22 パーセンタイル:83.4(Instruments & Instrumentation)

In order to clarify the effects of water on performances of a Polymer Electrolyte Fuel Cell (PEFC), measurements of water distribution in a Japan Automobile Research Institute standard PEFC were carried out by means of neutron radiography. Furthermore, the cell voltage and the pressure drop between inlet and outlet of the air were simultaneously measured. From the measurements, the relation between cell voltage, pressure drop and movement of the water plug in the channel was confirmed. The PEFC performances were recovered as the water plug evacuated. Condensed water in the channel decreased with the relative humidity of air. However, it may affect the MEA permanence. Therefore, the most appropriate operating conditions should be decided for taking into account both the cell performances and the permanencies.


Controlling the phase matching conditions of optical parametric chirped-pulse amplification using partially deuterated KDP

小川 奏; 末田 敬一*; 赤羽 温; 青山 誠; 辻 公一; 藤岡 加奈*; 金邉 忠*; 山川 考一; 宮永 憲明*

Optics Express (Internet), 17(10), p.7744 - 7749, 2009/05

 被引用回数:12 パーセンタイル:54.45(Optics)



Spectroscopic characterization of ultrashort laser driven targets incorporating both Boltzmann and particle-in-cell models

Sherrill, M. E.*; Abdallah, J.*; Csanak, G.*; Dodd, E. S.*; 福田 祐仁; 赤羽 温; 青山 誠; 井上 典洋*; 上田 英樹*; 山川 考一; et al.

High-Power Laser Ablation VII (Proceedings of SPIE Vol.7005), p.70051R_1 - 70051R_11, 2008/06

A model that solves simultaneously both the electron and atomic kinetics was used to generate synthetic X-ray spectra to characterize high intensity ultrashort-laser-driven target experiments. A particle-in-cell simulation was used to model the laser interaction for both cluster and foil targets and provided the initial electron energy distribution function (EEDF) for a Boltzmann solver. Though this model suggests that both Ar cluster and Ti foil plasmas are held in a highly non-equilibrium state for both the EEDF and the ion level populations for several picoseconds, the spectral line features of the foil experiment was shown to evolve too quickly to be seen by current ultrafast time resolved spectrometers.


Spin-lattice instability to a fractional magnetization state in the spinel HgCr$$_{2}$$O$$_{4}$$

松田 雅昌; 植田 浩明*; 吉川 明子*; 田中 良和*; 勝又 紘一*; 鳴海 康雄*; 稲見 俊哉; 上田 寛*; Lee, S.-H.*

Nature Physics, 3(6), p.397 - 400, 2007/06

 被引用回数:92 パーセンタイル:93.17(Physics, Multidisciplinary)

フラストレート反強磁性体は、磁性と構造の自由度が相互に深くかかわり合い、興味ある現象を示すことが大きな特徴である。特にACr$$_{2}$$O$$_{4}$$(A=Hg, Cd)は磁場中の広い領域で磁化1/2のプラトー状態を示すことが磁化の研究から明らかになっている。この現象はスピン格子相互作用に起因していることが理論的研究から示唆されていたが、実験はまだ行われていなかった。われわれは、HgCr$$_{2}$$O$$_{4}$$粉末を用いて磁場中での中性子回折実験とX線回折実験を行った。その結果、プラトー状態ではP4$$_{3}$$32の対称性を持つ磁気構造が安定になるように結晶構造もP4$$_{3}$$32の対称性を持つ構造に転移することを明らかにした。これは、フラストレート反強磁性体における強いスピン-格子相互作用をあらわす重要な結果である。


Pressure effect of electrical resistivity and AC specific heat in CePtAl

中島 美帆*; 植田 泰輝*; 清水 克哉*; 中島 弘*; Thamizhavel, A.*; 立岩 尚之; 芳賀 芳範; 辺土 正人*; 上床 美也*; 摂待 力生*; et al.

Journal of Magnetism and Magnetic Materials, 310(2, Part1), p.e9 - e11, 2007/03

キャントした強磁性物質であるCePtAlについてダイヤモンドアンビルセルを用いた高圧下電気抵抗・比熱測定を行った。圧力が増加すると磁気転移温度$$T_{rm C1}$$は単調に増加して8GPa以上で一定値を示す。さらに圧力を加えると転移温度は急激に減少し10.3から10.9GPaまでの狭い圧力範囲で消滅する。磁気臨界点は一次相転移点であると推測される。交流比熱測定でも類似の結果が得られた。


Spectroscopic characterization of an ultrashort-pulse-laser-driven Ar cluster target incorporating both Boltzmann and particle-in-cell models

Sherrill, M. E.*; Abdallah, J. Jr.*; Csanak, G.*; Dodd, E. S.*; 福田 祐仁; 赤羽 温; 青山 誠; 井上 典洋*; 上田 英樹*; 山川 考一; et al.

Physical Review E, 73(6), p.066404_1 - 066404_6, 2006/06

 被引用回数:29 パーセンタイル:77.97(Physics, Fluids & Plasmas)



Coupled electron and atomic kinetics through the solution of the Boltzmann equation for generating time-dependent X-ray spectra

Sherrill, M. E.*; Abdallah, J. Jr.*; Csanak, G.*; Kilcrease, D. P.*; Dodd, E. S.*; 福田 祐仁; 赤羽 温; 青山 誠; 井上 典洋*; 上田 英樹; et al.

Journal of Quantitative Spectroscopy & Radiative Transfer, 99(1-3), p.584 - 594, 2006/05

 被引用回数:2 パーセンタイル:13.72(Optics)



Selective transition to the closely-lying states Cs(7$$D$$$$_{3/2}$$) and Cs(7$$D$$$$_{5/2}$$) by femtosecond laser pulses

山田 秀尚; 横山 啓一; 寺西 慶哲*; 杉田 明宏; 白井 稔三*; 青山 誠; 赤羽 温; 井上 典洋*; 上田 英樹*; 山川 考一; et al.

Physical Review A, 72(6), p.063404_1 - 063404_5, 2005/12

 被引用回数:6 パーセンタイル:32.38(Optics)



Magnetic property and pressure effect of a single crystal CeRhGe

植田 泰輝*; 本田 大輔*; 城本 智行*; 目時 直人; 本多 史憲*; 金子 耕士; 芳賀 芳範; 松田 達磨; 竹内 徹也*; Thamizhavel, A.*; et al.

Journal of the Physical Society of Japan, 74(10), p.2836 - 2842, 2005/10

 被引用回数:14 パーセンタイル:62.24(Physics, Multidisciplinary)

We measured the electrical resistivity, specific heat, magnetic susceptibility, high-field magnetization, neutron scattering and electrical resistivity under pressure for CeRhGe. The anisotropy of the magnetic susceptibility and magnetization are very large, reflecting the orthorhombic crystal structure. The magnetic easy-axis is found to be oriented along the $$a$$-axis. From the neutron scattering experiment, the magnetic structure is, however, not simple, indicating an incommensurate antiferromagnetic structure. The magnetic susceptibility and magnetization were analyzed on the basis of the crystalline electric field scheme of localized-4$$f$$ energy levels, indicating a very large splitting energy of the 4$$f$$ levels.

63 件中 1件目~20件目を表示