1. Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo, Kyoto 615-8510, Japan, Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan, and Division of Natural Science, Osaka Kyoiku University, Asahigaoka, Kashiwara, Osaka 582-8582, Japan