Search Results 1-20 of 418

  • Investigation of recombination front region in detached plasmas in a linear divertor plasma simulator

    吉川 正志 , N. Ohno , M. Seki , H. Ohshima , H. Tanaka , S. Kajita , Y. Hayashi , H. Natsume , H. Takano , I. Saeki , Masayuki YOSHIKAWA , H. van der Meiden

    … We have investigated detailed plasma structure around the recombination front region (RFR), where volume electron-ion recombination (EIR) strongly occurs in detached plasmas, by using two-dimensional (2D) movable probe system as well as laser Thomson scattering diagnostics. … The 2D distribution of electron density, electron temperature, and plasma potential around the RFR, has been revealed for the first time. …

    Nuclear Materials and Energy (19), 458-462, 2019-05

    IR 

  • Grüneisen parameter and thermal expansion near magnetic quantum critical points in itinerant electron systems

    Watanabe Shinji , Miyake Kazumasa

    … By considering the zero point as well as thermal spin fluctuation under the stationary condition, the specific heat for each class of the magnetic quantum critical point (QCP) specified by the dynamical exponent z = 3 [feorromagnetism (FM)] and z = 2 [antiferromagnetism (AFM)] and the spatial dimension (d = 3 and 2) is shown to be expressed as CV = Ca − Cb, where Ca is dominant at low temperatures, reproducing the past SCR criticality endorsed by the renormalization group theory. …

    Physical Review B 99(3), 035108-1-035108-25, 2019-01-03

    IR 

  • Development of Proton-Electron-Coupled Organic Crystals  [in Japanese]

    Mori Hatsumi

    … <p>The highly "electron-electron" correlated researches have been vigorously developed in π-, d-, and f-electron systems. … Moreover, "electron-proton" coupled studies have attracted much attentions in π-electron based organic crystals. …

    Butsuri 74(2), 82-92, 2019

    J-STAGE 

  • Intermittent Magnetic Fluctuations Associated with High-Temperature Bubbles in an ECR Plasma

    YOSHIMURA Shinji , TERASAKA Kenichiro , TANAKA Masayoshi Y.

    … <p>Magnetic probe measurement has been performed in a cylindrical electron cyclotron resonance plasma in which localized high temperature electron region, i.e. high-temperature bubble, has been generated intermittently. … It is found that the high-temperature bubble is accompanied by a pulsed magnetic fluctuation perpendicular to the external magnetic field. …

    Plasma and Fusion Research 14(0), 3401081-3401081, 2019

    J-STAGE 

  • Ultrafast Electron Solvation in Room Temperature Ionic Liquid Observed by Femtosecond Time-resolved Near-IR Spectroscopy

    Ye Manping , Iwata Koichi

    … <p>The solvation process of electrons reflects the solvent structure and its fluctuation sensitively. … The solvation process of electrons in room-temperature ionic liquid <i>N</i>,<i>N</i>,<i>N</i>-trimethyl-<i>N</i>-propylammonium bis(trifluoromethylsulfonyl) amide, N<sub>1113</sub><sup>+</sup> … A broad absorption band from the solvated electrons shows a continuous blue-shift of 0.09 eV within 1 ns of electron injection. …

    Chemistry Letters 48(5), 422-425, 2019

    J-STAGE 

  • Nucleation Processes of Cosmic Dust Investigated by Microgravity Experiments using an Airplane

    KIMURA Yuki , ISHIZUKA Shinnosuke , ŠTURM Sašo , TANAKA Kyoko .K. , YAMAZAKI Tomoya , Fumiaki SAITO , SATOH Yosuke , TSUKAMOTO Katsuo , INATOMI Yuko

    … We show the details of our experiments using an aircraft including results of in-situ observation employing an interferometer and ex-situ transmission electron microscopy to reveal the difficulty of nucleation and variability of nucleation processes. …

    International journal of microgravity science and application 35(3), 350305, 2018

    J-STAGE 

  • Structural Fluctuation in Alloy Nanoparticles Revealed by Time-Resolved High-Voltage Electron Microscopy  [in Japanese]

    Sato Kazuhisa , Yasuda Hidehiro

    … with an ultra-high voltage electron microscope equipped with a direct electron detection camera. … Electron-irradiation-enhanced ordering occured at 573 K with 1 MeV electrons at a dose rate of 8.9 × 10<sup>24</sup> … The observed kinetic ordering temperature of 573 K is significantly lower than that reported previously (> …

    KENBIKYO 53(2), 80-84, 2018

    J-STAGE 

  • Enhanced relaxation behavior in Bi<sub>2</sub>O<sub>3</sub> modified (Ba<sub>0.85</sub>Ca<sub>0.15</sub>)(Zr<sub>0.1</sub>Ti<sub>0.9</sub>)O<sub>3</sub> ceramics

    WANG Xiaofang , LIANG Pengfei , YANG Zupei

    … X-ray diffraction analysis revealed that all specimens displayed typical perovskite structure at room temperature. … Scanning electron microscope results showed that the introduction of Bi element could effectively reduce the sintering temperature and favor grain refinement of BCZT ceramics. …

    Journal of the Ceramic Society of Japan 126(6), 440-446, 2018

    J-STAGE 

  • Suppression of Ion-Scale Microtearing Modes by Electron-Scale Turbulence via Cross-Scale Nonlinear Interactions in Tokamak Plasmas

    Maeyama S. , Watanabe T.-H. , Ishizawa A.

    … Gyrokinetic turbulence simulations are applied for the first time to the cross-scale interactions of microtearing modes (MTMs) and electron-temperature-gradient (ETG) modes. … The investigation of the fluctuation response in a multiscale simulation including both types of instabilities indicates that MTMs are suppressed by ETG turbulence. …

    Physical Review Letters (119), 195002-195002, 2017-11

    IR 

  • New quantum criticality revealed under pressure

    Watanabe Shinji , Miyake Kazumasa

    … Unconventional quantum critical phenomena observed in Yb-based periodic crystals such as YbRh2Si2 and β-YbAlB4 have been one of the central issues in strongly correlated electron systems. … The T/H scaling where the magnetic susceptibility can be expressed as a single scaling function of the ratio of the temperature T to the magnetic field H has been discovered in the quasicrystal, which is essentially the same as that observed in β-YbAlB4. …

    Japanese Journal of Applied Physics 56(5), 05FA01, 2017-03-09

    IR 

  • Microscopic Analysis of Graphene and Carbon Nanotube Growth

    Homma Yoshikazu

    … We have observed chemical vapor deposition (CVD) processes of single-walled carbon nanotubes (SWCNTs) using scanning electron microscopy (SEM) by repeating ethanol exposure and observation without ethanol at an elevated temperature. … Both the observations of growth on the substrate and that between mesa patterns suggest fluctuation of SWCNT growth direction during CVD cause SWCNTs falling on the substrate, forming nearest neighbor suspension and bundling. …

    Journal of Surface Analysis 24(2), 151-158, 2017

    J-STAGE 

  • Current Status of Spin Fluctuation Theory of Magneto-volume Effects in Itinerant Electron Magnets  [in Japanese]

    TAKAHASHI Yoshinori

    … <p>Magneto-volume effect means the phenomena where volume of magnet changes spontaneously with temperature or as the effect of externally applied magnetic field. … In this treatment of the effect on itinerant electron magnets, the same free energy is used in the derivation of magnetic entropy and specific heat. …

    Journal of the Japan Society of Powder and Powder Metallurgy 64(4), 159-162, 2017

    J-STAGE 

  • High time resolved electron temperature measurements by using the multi-pass Thomson scattering system in GAMMA 10/PDX

    Yoshikawa Masayuki , Yasuhara Ryo , Ohta Koichi , Chikatsu Masayuki , Shima Yoriko , Kohagura Junko , Sakamoto Mizuki , Nakashima Yousuke , Imai Tsuyoshi , Ichimura Makoto , Yamada Ichihiro , Funaba Hisamichi , Minami Takashi , 吉川 正志 , 小波藏 純子 , 坂本 瑞樹 , 中嶋 洋輔 , 今井 剛 , 市村 真

    … High time resolved electron temperature measurements are useful for fluctuation study. … Finally, time dependent electron temperatures were obtained in MHz sampling. …

    Review of scientific instruments 87(11), 11D617, 2016-11

    IR 

  • Origin of Quantum Criticality in Yb-Al-Au Approximant Crystal and Quasicrystal

    Watanabe Shinji , Miyake Kazumasa

    … We find that charge-transfer mode between 4f electron at Yb on the 3rd shell and 3p electron at Al on the 4th shell in Tsai-type cluster is considerably enhanced with almost flat momentum dependence. …

    Journal of the Physical Society of Japan 85(6), 063703-1-5, 2016-06

    IR 

  • Quantum criticality and emergence of the T/B scaling in strongly correlated metals

    Watanabe Shinji , Miyake Kazumasa

    … A new type of scaling observed in heavy-electron metal β-YbAlB4, where the magnetic susceptibility is expressed as a single scaling function of the ratio of temperature T and magnetic field B over four decades, is examined theoretically. … Emergence of the T/B scaling indicates the presence of the small characteristic temperature of the critical Yb-valence fluctuation due to the strong local correlation effect. …

    Journal of Magnetism and Magnetic Materials (400), 13-16, 2016-02-15

    IR 

  • Validation of the Digital Correlation ECE Measurement Technique using Low-Frequency Fluctuation in LHD

    TSUCHIYA Hayato , INAGAKI Shigeru , TOKUZAWA Tokihiko , TAMURA Naoki , NAGAYAMA Yoshio , LHD Experiment Group

    … The experiment was conducted in the 18th cycle experiments in the large helical device (2014 fiscal year) and a several kHz electron temperature fluctuation was detected in the high ion temperature plasma. …

    Plasma and Fusion Research 11(0), 2402072-2402072, 2016

    J-STAGE 

  • Development of Electron Bernstein Emission Diagnostic for Heliotron J

    NAGASAKI Kazunobu , KADO Shinichiro , KOBAYASHI Shinji , YAMAMOTO Satoshi , OHSHIMA Shinsuke , WEIR Gavin , KONOSHIMA Shigeru , KENMOCHI Naoki , OTANI Yoshiaki , YOSHIMURA Yasuo , MARUSHCHENKO Nikolai , NAKAMURA Yuji , MIZUUCHI Tohru , KAMIOKA Sohei , IGAMI Hiroe , VOLPE Francesco , STANGE Torsten , SAKAMOTO Kinzo , OKADA Hiroyuki , MINAMI Takashi

    … <p>Electron Bernstein Emission (EBE) diagnostic system using Ordinary (O) - eXtraordinary (X) - Bernstein (B) mode conversion process has been developed for determining electron temperature profiles at overdense plasmas in a helical-axis heliotron device, Heliotron J. … Effect of density fluctuation on O-X mode conversion efficiency is also discussed. …

    Plasma and Fusion Research 11(0), 2402095-2402095, 2016

    J-STAGE 

  • Comparison of Ion Internal Transport Barrier Formation between Hydrogen and Helium Dominated Plasmas

    NAGAOKA Kenichi , YAMADA Hiroshi , TAKEIRI Yasuhiko , IDA Katsumi , YOSHINUMA Mikiro , the LHD Experiment Group , TAKAHASHI Hiromi , TANAKA Kenji , OSAKABE Masaki , MURAKAMI Sadayoshi , MAETA Shogo , YOKOYAMA Masayuki , FUJII Keisuke , NAKANO Haruhisa

    … The central ion temperature was investigated as a function of the hydrogen density ratio (<i>n</i><sub>H</sub>/(<i>n</i><sub>H</sub>+<i>n</i><sub>He</sub>)). … The central ion temperature increases with the decrease of the hydrogen density ratio, while the electron temperature does not change significantly. …

    Plasma and Fusion Research 11(0), 2402106-2402106, 2016

    J-STAGE 

  • Influence of Substrate Temperature on Mechanical Properties of SiO<sub>2</sub> and Nb<sub>2</sub>O<sub>5</sub> Optical Thin Films Prepared by High-Density Plasma Assisted Vapor Deposition  [in Japanese]

    MORIIZUMI Yasushi , HONMA Hideo , TAKAI Osamu

    … The substrate temperature strongly affects optical thin film durability and determines the thin film structure. … Therefore, substrate temperature fluctuation from 25 ℃ to 400 ℃ during deposition was verified to improve mechanical properties while maintaining optical properties. … For these analyses, cross-sections of the tested films were observed using SEM(Scanning Electron Microscope). …

    Journal of The Surface Finishing Society of Japan 67(2), 97-104, 2016

    J-STAGE 

  • Radiation Measurements using Adaptive-array Technique  [in Japanese]

    出射 浩 , 山本 真之

    Electron Cyclotron Emission (ECE) is thermal blackbody radiation coming from electron Larmor motion. … The ECE spectrum measurement is one of most popular electron temperature diagnostics in nuclear fusion plasma research. … The 2- and 3- dimensional imaging ECE diagnostics systems were used for electron temperature fluctuation measurements with high time resolution. …

    九州大学応用力学研究所所報 (149), 42-46, 2015-09

    IR  DOI 

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