Search Results:　 1-20 of 101

  • 1

    Mitigation Technologies for Damage Induced by Pressure Waves in High-Power Mercury Spallation Neutron Sources (III) : Consideration of the Effect of Microbubbles on Pressure Wave Propagation through a Water Test

    NAOE Takashi , KOGAWA Hiroyuki , FUTAKAWA Masatoshi , IDA Masato

    … The effects of microbubbles dispersed in a liquid on a high-rising-rate pressure wave were experimentally investigated with water. … It was found that when the microbubbles are sufficiently small (e.g., about 50 μm in peak radius), the amplitude of wall vibration induced by the spark-induced pressure wave is dramatically decreased with an increase in void fraction. …

    Journal of Nuclear Science and Technology 48(6), 865-872, 2011-06-01

    J-STAGE CrossRef References (45)

  • 2

    Study and development of ultra-short pulses Yb:YAG laser surpassed limit of the fluorescence spectrum width  [in Japanese]

    SASATANI Yoshinobu , HITOTSUYA Hiroyuki , KONDOU Yutaka , IGARASHI Tatsuya , WATANABE Seiji , MATSUBARA Shinichi , ISHIDA Yuzo , KAWATO Sakae

    小型、高効率な超短パルスレーザーの実用化を目指して、半導体レーザーダイオード(LD)励起Yb:YAGレーザーによるカー媒質を使用したカーレンズモード同期動作を試みた。最大励起時におけるレーザー発振器のCW動作では、出力2.3Wを得ることができた。スロープ効率は34.2%、ビーム品質(M^2)は1.72であった。また、この発振器に半導体不飽和吸収鏡(SESAM)を用いることで、連続モード同期動作を観 …

    Technical report of IEICE. LQE 111(56), 49-52, 2011-05-13

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  • 3

    Preparation and Characterization of Pyramidal-shaped EM-wave Absorbers Produced by Smoked Roof-tile Process (No. 2)  [in Japanese]

    YAMAMOTO Shinichiro , NAKAMURA Tatsuya , HATAKEYAMA Kenichi , HIROSE Mika , YOSHIUCHI Satoshi

    … EM-wave pyramidal-shaped absorbers produced by the traditional smoked roof-tile production process are introduced. … It has a superior long-term stability and thermal stability against high power incidence. … The relationship between EM-wave absorption and surface conductivity are discussed. …

    Journal of the Japan Society of Powder and Powder Metallurgy 58(3), 181-185, 2011-03-15

    J-STAGE CrossRef References (9)

  • 4

    Study on Absorption Characteristics of Pyramidal Absorbers Produced by Roof-tile Smoking Process  [in Japanese]

    Yamashita Norihito , Yamamoto Shinichiro , Nakamura Tatsuya , Hatakeyama Kenichi , Hirose Mika , Yoshiuchi Satoshi

    日本古来の瓦製造法の一つであるいぶしは,瓦粘土から成る成形体を電気炉内で焼成・燻化する手法のことである.筆者らはこれまで,瓦粘土ピラミッド成形体を作製し,燻化処理により成形体表面に導電性のカーボン膜を形成させ,ピラミッド形電波吸収体を試作してきた.本研究では,ピラミッド吸収体表面の抵抗値を制御することにより,吸収特性が改善可能かどうか検討した.さらに,FDTD法により電波吸収特性を計算した.

    IEICE technical report. Electromagnetic compatibility 110(402), 73-78, 2011-01-21

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  • 5

    Imaging Radio-Frequency Power Distributions by an EBG Absorber

    YAGITANI Satoshi , KATSUDA Keigo , NOJIMA Masayuki , YOSHIMURA Yoshiyuki , SUGIURA Hirokazu

    … A thin electromagnetic band-gap (EBG) absorber is employed to capture the 2-d image of radio-frequency (RF) power distribution. … The EBG absorber consists of an array of mushroom unit cells formed on a thin dielectric substrate with a metal backplane, and lumped resistors interconnecting the surface patches of the mushrooms. …

    IEICE Transactions on Communications E94.B(8), 2306-2315, 2011

    IR J-STAGE CrossRef

  • 6

    An Fundamental Study on Small Anechoic Chamber Using Visibility Wave Absorbers  [in Japanese]

    KATO Shunki , YASUZUMI Takenori , TANAKA Toshiaki , HASHIMOTO Osamu

    本稿では,視認性を有する金属布を用いたシールドテントの内壁に,炭素短繊維を用いた多層型電波吸収体を配置した小型電波暗室に関する基礎的検討を行った.まず本吸収体を測定した結果,約2.0GHZ付近において広帯域な吸収特性を有することがわかった.次に,シールドテント単体およびテント内部に吸収体を配置した場合のシールド特性および電力分布について検討した.その結果,提案の小型電波暗室は約6.0GHZまで良好 …

    IEICE technical report. Electromagnetic compatibility 110(332), 81-86, 2010-12-03

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  • 7

    Analytic Study on the Electric Wave Environment of ETC Lane Located near the Sound Insulation Wall by Putting in the Wave Absorber  [in Japanese]

    ISHIBASHI Kiichi , WAKABAYASHI Yosiyuki , HASHIMOTO Osamu

    本研究では,遮音壁近傍ETCモデルにおいて,ETCアンテナ付近の電波環境についてレイトレース法を用いて解析的に検討した.具体的には,まず,遮音壁が及ぼす通信領域周辺の受信電力への影響について確認した.次に,路面に水膜を配置した場合,水膜及びタンクローリーを配置した場合の受信電力を検討した.この結果,水膜及びタンクローリーを配置することで電波環境は悪化し,隣接レーンにおいて基準値以上の受信電力を確認 …

    IEICE technical report. Electromagnetic compatibility 110(236), 19-24, 2010-10-14

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  • 8

    Analytic Study on the Electric Wave Environment of ETC Lane Located near the Sound Insulation Wall by Putting in the Wave Absorber  [in Japanese]

    ISHIBASHI Kiichi , WAKABAYASHI Yosiyuki , HASHIMOTO Osamu

    本研究では,遮音壁近傍ETCモデルにおいて,ETCアンテナ付近の電波環境についてレイトレース法を用いて解析的に検討した.具体的には,まず,遮音壁が及ぼす通信領域周辺の受信電力への影響について確認した.次に,路面に水膜を配置した場合,水膜及びタンクローリーを配置した場合の受信電力を検討した.この結果,水膜及びタンクローリーを配置することで電波環境は悪化し,隣接レーンにおいて基準値以上の受信電力を確認 …

    IEICE technical report. Microwaves 110(237), 19-24, 2010-10-14

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  • 9

    S0303-2-6 Thermoelastic problem of FGM Type Cylindrical Electromagnetic Wave Absorbers Subjected to Asymmetrical Heating  [in Japanese]

    Takahashi Satoshi , Sugano Yoshihiro

    … We have been proposed functionally graded material type electromagnetic wave absorbers (FGM type EM-wave absorbers) for the improvement in absorption performance and material strength. … In this study, we investigate a plane-strain thermoelastic problem of the FGM type EM-wave absorbers for a hollow cylinder subjected to irradiation power and convective heat load. …

    年次大会講演論文集 : JSME annual meeting 2010(1), 105-106, 2010-09-04

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  • 10

    Microjoule Pulses from a High-Efficient Ytterbium-Doped Yttrium Aluminum Garnet Chirped-Pulse Oscillator

    Yinghong Xue , Sadao Uemura , Kenji Torizuka

    … A maximum continuous-wave output power of 32.0 W was obtained with a high conversion efficiency of 68.4%. … An 8.2-MHz low-repetition-rate mode-locked laser was designed using a semiconductor saturable absorber mirror (SESAM) and a multiple-pass cavity (MPC). …

    Jpn J Appl Phys 49(2), 022702-022702-4, 2010-02-25

    The Japan Society of Applied Physics

  • 11

    2D Radio Wave Distribution Imager by an EBG Absorber  [in Japanese]

    YAGITANI Satoshi , KATSUDA Keigo , SHIMIZU Takao , YAMANAKA Yusuke , MORITA Satoshi , YOSHIMURA Yoshiyuki , SUGIURA Hirokazu

    マッシュルーム型EBG(Electromagnetic Band Gap)構造に抵抗素子を付加した薄板型電波吸収体を用い,個々のマッシュルーム(方形電極)で吸収された電波強度を計測することで,吸収体表面に入射した電波の2次元強度分布を高速に計測する手法を提案する.EBG電波吸収体の吸収特性をシミュレーション,等価回路及び実測により評価した.700MHz〜1.8GHzの範囲で吸収(計測)周波数を可変 …

    IEICE technical report. Electromagnetic compatibility 109(370), 47-52, 2010-01-14

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  • 12

    Compact Passively Q-Switched Yb:YAG Multipass Ring Lasers

    Yi Jui-Yun , Chen Li-Hsuan , Peng Hsin , Huang Sheng-Lung

    … An efficient and compact continuous-wave Yb:YAG laser with a slope efficiency of 50.3% with respect to the absorbed power was demonstrated using a multipass ring cavity (MPRC). … When Cr:YAG was used as the saturable absorber for passive Q-switching, various pulse widths and repetition rates were obtained. …

    Jpn J Appl Phys 48(11), 112501-112501-6, 2009-11-25

    The Japan Society of Applied Physics

  • 13

    Study on the Temperature Limitation of the Injecting Power to a Pyramidal EM-Wave Absorber

    SASAGAWA Tetsuhiro , WATANABE Shinya , HASHIMOTO Osamu , SAITO Toshifumi , KURIHARA Hiroshi

    … In this paper, first the temperature distribution of the pyramidal EM-wave absorber is calculated in the coupled method. … Next, the injected power to the EM-wave absorber is changed to estimate the maximum power density that the EM-wave absorber can resist. …

    IEICE Transactions on Electronics 92(10), 1319-1321, 2009-10-01

    J-STAGE CrossRef References (8)

  • 14

    G0301-2-2 Analytical Study on Absorption performances and Thermal Stresses of FGM Type Cylindrical Electromagnetic Wave Absorbers  [in Japanese]

    Takahashi Satoshi , Sugano Yoshihiro

    … In this study, we propose functionally graded material (FGM) type electromagnetic wave absorbers for a hollow cylinder and investigate an electromagnetic noise problem and a plane-strain thermoelastic problem of those absorbers. … We present the analytical solutions of electromagnetic and temperature fields in the FGM type cylindrical absorbers subjected to the irradiation power. …

    年次大会講演論文集 : JSME annual meeting 2009(1), 23-24, 2009-09-12

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  • 15

    OS0108 Thermoelastic Stresses and Electromagnetic Fields in Cylindrical Wave Absorbers with Controlled Graded Compositions  [in Japanese]

    TAKAHASHI Satoshi , SUGANO Yoshihiro

    … We propose the electromagnetic wave absorbers with controlled graded compositions (FGM type EM-wave absorbers) for a hollow cylinder and investigate an electromagnetic noise problem and a plane-strain thermoelestic problem of those FGM type EM-wave absorbers. … We present the analytical solutions of electromagnetic and temperature fields in the FGM type cylindrical EM-wave absorbers subjected to an irradiation power. …

    M&M材料力学カンファレンス 2009, 83-85, 2009-07-24

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  • 16

    Preparation and Characterization of Pyramidal-shaped EM-wave Absorbers Produced by Smoked Roof-tile Process  [in Japanese]

    NAKAMURA Tatsuya , HATAKEYAMA Kenichi , HIROSE Mika , YOSHIUCHI Satoshi

    … EM-wave absorbers were prepared by a smoked roof-tile process. … The roof-tile process produced a carbon-coated surface layer on the pyramidal-shaped substrate, which exhibited good electrical conductivity and led to good EM-wave absorption in the microwave frequency range. … In addition, the absorbers exhibited strong resistance to high-power incident EM-waves, and the environmental stability in ambient atmosphere is expected. …

    Journal of the Japan Society of Powder and Powder Metallurgy 56(7), 461-464, 2009-07-15

    J-STAGE CrossRef References (8)

  • 17

    Coupling Effects and Thermal Stresses of Functionally Graded Type Electromagnetic Wave Absorbers under High Power Injection  [in Japanese]

    TAKAHASHI Satoshi , SUGANO Yoshihiro

    … Functionally graded (FG) type electromagnetic (EM) wave absorbers have been proposed for the improvement in absorption performance and material strength. … In this paper, we investigate coupling effects on the performance of the FG type EM wave absorbers for plate under high power injection and transient thermal stresses in the absorption systems. …

    Transactions of the Japan Society of Mechanical Engineers. A 75(753), 604-611, 2009-05-25

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  • 18

    Practical Evaluation Method for Anisotropic EM-Wave Absorbers in Microwave Frequencies : Reflection Power and Anisotropy  [in Japanese]

    YAMAMOTO Shinichiro , TAKAE Yoshiaki , HATAKEYAMA Kenichi

    マイクロ波帯における異方性電波吸収体の実用的評価法について述べる,方向性の軸での反射係数は最大値或いは最小値を示す.方向性の軸に入射波偏波を合わせたときの反射波について,その反射波電力と異方性の大きさとの関係について検討した.さらに,反射特性に僅かな異方性を示す電波吸収体の評価として,その吸収量に注目し,検討した.

    IEICE technical report. Electromagnetic compatibility 108(307), 33-38, 2008-11-13

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  • 19

    1153 Thermal Stresses and Coupling Effects in Functionally Graded Type Electromagnetic Wave Absorbers under High Power Injection  [in Japanese]

    Takahashi Satoshi , Sugano Yoshihiro

    … Functionally graded (FG) type electromagnetic (EM) wave absorbers have been proposed for the improvement in absorption performance and material strength. … In this study, coupling effects on the performance of the FG type EM wave absorbers and thermal stresses in the absorbers are investigated. …

    年次大会講演論文集 : JSME annual meeting 2008(1), 119-120, 2008-08-02

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  • 20

    A Study on Temperature Distribution of a Wave Absorber Composed of Parallel Resistive Films under High Power Injection  [in Japanese]

    WATANABE Eriko , WATANABE Shinya , HASHIMOTO Osamu , SAITO Toshifumi , KURIHARA Hiroshi

    電気学会研究会資料. EMT, 電磁界理論研究会 2008(50), 175-179, 2008-07-24

    References (13)