1. Contribution from Graduate School of Material Science, Himeji Institute of Technology, University of Hyogo, Kohto, Kamigori, Hyogo 678-1297, Japan, Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan, and Chemistry Department for Materials, Faculty of Engineering, Mie University, Kamihama, Tsu, Mie 514-8507, Japan