1. Institute
for Materials Chemistry and Engineering, Kyushu University, 6-1
Kasuga-Koen, Kasuga, Fukuoka 816-8580, Japan
2. Panasonic Corporation, 1006 Kadoma, Kadoma City, Osaka 571-8506, Japan
3. Department
of Electrical Engineering, Keio University, 3-14-1 Hiyoshi,
Kouhokuku, Yokohama 223-8522, Japan