1. Department of Physics and Electronics, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai-shi, Osaka 599-8531, Japan
2. Sekisui Chemical Co., Ltd. 2-2, Kamichoshi-cho, Kamitoba, Minami-ku, Kyoto-shi, Kyoto 601-8105, Japan