1. Faculty of Science, Kwansei Gakuin University, Gakuen, Sanda 669-1337, Japan, Kobe City University of Foreign Studies, Gakuen-Higashimachi, Nishi-ku, Kobe 651-2187, Japan, and Department of Materials Science and Chemical Engineering, Faculty of Engineering, Shizuoka University, Johoku, Hamamatsu 432-8561, Japan