1. Nippon Sanso Corporation, Electronic Business Division, Yamanashi Laboratory, 3054‐3 Shimokurosawa, Takane‐cho, Kitakoma‐gun, Yamanashi 408, Japan
2. Department of Applied Chemistry, Faculty of Science and Technology, Keio University, 3‐14‐1 Hiyoshi, Kohoku, Yokohama 223, Japan
3. Department of Applied Chemistry and Biotechnology, Faculty of Engineering, Yamanashi University, 1 Takeda, Kofu‐shi, Yamanashi 400, Japan