Yamamoto Ken-ichi

写真a

Title

Associate Professor

Researcher Number(JSPS Kakenhi)

60284957
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Current Affiliation Organization 【 display / non-display 】

  • Duty   University of the Ryukyus   Faculty of Engineering   School of Engineering_Electrical and Systems Engineering Program   Associate Professor  

  • Concurrently   University of the Ryukyus   Graduate School of Engineering and Science   Electrical Energy and Systems Control Engineering   Associate Professor  

  • Concurrently   University of the Ryukyus   Graduate School of Engineering and Science   Material,Structural and Energy Engineering   Associate Professor  

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Academic degree 【 display / non-display 】

  • Gifu University -  Doctor of Engineering

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External Career 【 display / non-display 】

  • 2003.08
    　
    　

    University of the Ryukyus, Faculty of Engineering, Department of Electrical and Electronics Engineering, Electromagnetic Energy Engineering, Associate Professor  

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Research Interests 【 display / non-display 】

  • Magnetics

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Research Areas 【 display / non-display 】

  • Nanotechnology/Materials / Structural materials and functional materials

  • Manufacturing Technology (Mechanical Engineering, Electrical and Electronic Engineering, Chemical Engineering) / Measurement engineering

  • Manufacturing Technology (Mechanical Engineering, Electrical and Electronic Engineering, Chemical Engineering) / Electric and electronic materials

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Research Theme 【 display / non-display 】

  • Magnetic domain observation

  • Magnetizing Process of Soft Magnetic Materials under Stress

  • Anomalous Permiability Increase Due to Stress Changes on Magnetic Materials

  • High accuracy magnetic measurement in high-frequency region

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Thesis 【 display / non-display 】

  • 弾性領域の応力下における軟質磁性材料の磁化特性に関する研究

    1996.03

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Published Papers 【 display / non-display 】

  • Permeability measurement using two-coil method near resonance frequency

    K.Yamamoto, Y.Narita, K.Ishiyama

    The papers of Jint Techical Meeting on "Magnetics" and "Linear Drives", IEE Japan   ( MAG-25-137 )   2025.12

    Type of publication: Research paper (research society, symposium materials, etc.)

    　View Summary

    Two-coil method for ac magnetic measurement has been commonly used, but its measurable frequency is restricted by the resonce between the secondary coil and the input capacitance. This papaer analyzes the measured magnetic loss using electrical circuit. It is shown that measured loss is a function of hte capacitance and it can be estimated using a linear fitting.

  • Reliability of magnetic measurements of soft magnetic materials near resonance frequency usin two-coil method

    Ken-ichi Yamamoto, Yoshimasa Narita, Kazushi Ishiyama

    27th Soft Magnetic Materials Conference, SMM27     2025.09 [ Peer Review Accepted ]

    Type of publication: Research paper (international conference proceedings)

  • Permeability measurement using two-coil method near resonance frequency

    K.Yamamoto, Y.Narita, K.Ishiyama

        2025.06

    Type of publication: Research paper (research society, symposium materials, etc.)

  • Effects of Coils on Precision of Magnetic Measurements for Low Permeability Toroidal Cores in High Frequency Region

    Yamamoto Ken-ichi, Narita Yoshimasa, Ishiyama Kazushi

    IEEJ Transactions on Fundamentals and Materials ( The Institute of Electrical Engineers of Japan )  143 ( 6 ) 216 - 221   2023.06 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

    　View Summary

    <p>High frequency magnetic measurements for low permeability toroidal cores are demonstrated using various primary and secondary coils on low permeability magnetic toroidal cores, and effects of coils on their precision is discussed. As the number of turns in primary and secondary coils are reduced, measured permeability shows higher dispersion. This fact relates to the deviation of the strength of magnetizing field due to the small number of primary windings. It is also demonstrated several winding methods of primary coil to reduce the dispersion.</p>

  • A study on magnetic measurement on low permeability toroidal cores in high frequency region

    K.Yamamoto, Y.Narita, K.Ishiyama

    The papers of Technical Meeting on Magnetics, IEE Japan ( IEE Japan )    2022.08

    Type of publication: Research paper (research society, symposium materials, etc.)

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Presentations 【 display / non-display 】

  • Effects of coils on accuracy of magnetic losses on low-loss toroidal cores in high-frequency region

    Ken-ichi Yamamoto, Yoshio Narita, K.Ishiyama

    26th Soft Magnetic Materials Conference (SMM26)  2023.09  -  2023.09 

  • Effects of compressive stress normal to the surface of grain-oriented electruical steel sheets

    K.Yamamoto, T.Hamada, S.Yanase

    13th Int. Workshop on 1&2-Dim. Magnetic measurement and testing  2014.09  -  2014.09 

  • 面圧縮力下における方向性電磁鋼板の磁気測定法

    山本健一, 浜田稔之, 柳瀬俊次

    沖縄支所大会  2013.12  -  2013.12 

  • 電磁鋼板の面圧方向圧縮力下での二次元磁気特性測定装置の検討

    藪下, 柳瀬,岡崎, Yun, 山本健一

    マグネティックス研究会  2013.12  -  2013.12 

  • Effects of compressive stress normal to the surfeace of non-oriented electrical steel sheets

    Ken-ichi Yamamoto, Shunji Yanase

    12th Int. Workshop on 1&2-Dim. Magnetic measurement and testing  2012.09  -  2012.09 

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Other External funds 【 display / non-display 】

  • Project Year: 2003  -  2003 

    Direct: 0 (YEN)  Overheads: 0 (YEN)  Total: 0 (YEN)

  • Project Year: 1995  -  1995 

    Direct: 0 (YEN)  Overheads: 0 (YEN)  Total: 0 (YEN)

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