Takayuki Doi1, Masaya Kokubo, Keiji Yamamoto, Takashi Takahashi. 1. Department of Chemical Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo 152, Japan, and Department of Materials Science and Engineering, Science University of Tokyo in Yamaguchi, 1-1-1 Daigaku-dori, Onoda, Yamaguchi 756, Japan.