1. Advanced Science Research Center, Japan Atomic Energy Research Institute (Tokai), Tokai-mura, Naka-gun, Ibaraki 319-11, Japan, Department of Applied Chemistry, School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-01, Japan, and Japan Atomic Energy Research Institute (Takasaki), 1233 Watanuki, Takasaki, Gunma, 370-12, Japan