1. Laboratory of Physics, Meikai University, Urayasu, Chiba 279
2. Electro-Chemical and Cancer Institute, Kokuryo, Chofu, Tokyo 182
3. Tokai University, Hiratuka, Kanagawa 259-12
4. Faculty of Engineering, Toyama Prefectural University, Toyama 939-03
5. Department of Electrical Engineering, Hiroshima Institute of Technology, Saeki-ku, Hiroshima 731-51