I have related to superconductivity these thirty years. In the first stage, I have devoted to the control of the charge and discharge of a superconductive magnet, from the stand point of power electronics . Then belonging to the Research Center of Superconductivity, I have succeeded in the four quadrant P-Q control of the SMES. Meanwhile, the high temperature superconductivity (HTSC) was discovered. Hereafter, my colleague have discovered the mystery of HTSC by lighting the HTSC film.
