1. Research Laboratory of Resources Utilization, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, 227, Japan
2. Central Research Institute, Japan Tobacco Inc, 6-2 Umegaoka, Midori-ku, Yokohama, 227, Japan
3. Research Department, Engineering Division, NOK Corporation, 4-3-1 Tsujido-shinmachi, Fujisawa-shi, 251, Japan