Updated on 2024/02/07


Ryuji Nishi


  • Doctor (Engineering)   Thesis ( 1997.3   Osaka University )

Research Interests

  • Electron Optics

Research Areas

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


  • Osaka University   Department of Electronic Engineering   Graduated

    1986.4 - 1990.3

  • Osaka University   Department of Electronic Engineering   Master's Course   Completed

    1990.4 - 1992.3

Research History

  • Osaka University   Research Assistant

    1992.4 - 1998.3

  • Osaka University   Research Assistant

    1998.4 - 2003.3

  • Osaka University   Research Assistant

    2003.4 - 2004.10

  • Osaka University

    2004.11 - 2007.3

  • Osaka University   Associate Professor

    2007.4 - 2020.3

  • Fukui University of Technology   Professor

    2020.4 - 2023.3

  • Osaka University


  • Fukui University of Technology   Professor


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Qualification acquired

  • Land Radio Engineer (1-2 class)

  • Chief Person of Radiation Handling (first and second kind)

  • Hygiene Engineering Hygiene Manager

  • X-ray Work Chief Person

  • Gamma Ray Penetration Photography Work Chief Person



  • Low-Aberration ExB Deflector Optics for Scanning Electron Microscopy Reviewed

    Momoyo Enyama, Jun Yamasaki, Ryuji Nishi, Hiroyuki Ito

    Microscopy   72 ( 5 )   399 - 407   2023.10

     More details

    To suppress aberrations in the signal electron optics of a scanning electron microscope, we propose ExB deflector (deflector with superimposed electric and magnetic fields) optics that cancel the aberrations generated during large-angle deflection. This improves the resolution of the angle or position of the signal electrons on the sample surface, allowing them to be discriminately detected. The proposed optics consist of two ExB deflectors and a transfer system with two 4-f systems, or systems that have four times the focal length, placed between them. This configuration maintains the symmetry of the electron beam trajectory throughout the transfer system such that aberrations generated by the first ExB deflector are negated by the second. The effect of the proposed optics was confirmed using a ray-tracing simulation of the electron beam, and the aberration was reduced to at most one-tenth of that in the case with only one ExB deflector. Furthermore, as an example, we examined the implementation of the proposed ExB deflector optics to resolve the signal electron angle and found that the sample emission angle range of 80° can be resolved with an angular resolution of 1°. Therefore, the proposed ExB deflector optics can be applied to the signal electron optics of a scanning electron microscope to improve the resolution of the signal electrons.

  • Application of ultra-high voltage electron microscope tomography to 3D imaging of microtubules in neurites of cultured PC12 cells Reviewed

    T. Nishida, R. Yoshimura, R. Nishi, Y. Imoto, Y. Endo

    Journal of Microscopy   278 ( 1 )   42 - 48   2020.4

     More details

    Electron tomography methods using the conventional transmission electron microscope have been widely used to investigate the three-dimensional distribution patterns of various cellular structures including microtubules in neurites. Because the penetrating power of electrons depends on the section thickness and accelerating voltage, conventional TEM, having acceleration voltages up to 200 kV, is limited to sample thicknesses of 0.2 μm or less. In this paper, we show that the ultra-high voltage electron microscope (UHVEM), employing acceleration voltages of higher than 1000 kV (1 MV), allowed distinct reconstruction of the three-dimensional array of microtubules in a 0.7-μm-thick neurite section. The detailed structure of microtubules was more clearly reconstructed from a 0.7-μm-thick section at an accelerating voltage of 1 MV compared with a 1.0 μm section at 2 MV. Furthermore, the entire distribution of each microtubule in a neurite could be reconstructed from serial-section UHVEM tomography. Application of optimized UHVEM tomography will provide new insights, bridging the gap between the structure and function of widely-distributed cellular organelles such as microtubules for neurite outgrowth.

    Key words: microtubule, neurite, section thickness, electron tomography, ultra-high voltage electron microscope

  • Study on higher performance of imaging and observation system in ultrahigh voltage electron microscopy

    Ryuji Nishi



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Teaching Experience

  • Digital Signal Processing

    Institution:Fukui University of Technology

  • Electron Beam Nano Imaging

    Institution:Osaka University