1. Advanced Key Technologies Division, National Institute for Materials Science; 1-1 Namiki, Tsukuba Ibaraki 305-0044 Japan
2. Department of Chemistry, Kanagawa University; 2946 Tsuchiya, Hiratsuka Kanagawa 259-1293 Japan
3. Department of Materials Science and Engineering, Kyoto University; Yoshida-Honmachi, Sakyo Kyoto 606-8501 Japan
4. Nanostructures Research Laboratory, Japan Fine Ceramics Center; 2-4-1 Mutsuno, Atsuta Nagoya 456-8587 Japan