1. Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, Rokko, Nada, Kobe 657-8501, Japan
2. Institute of Materials Structure Science, High Energy Accelerator Research Organization, 203-1 Shirakata, Tokai 319-1106, Ibaraki, Japan
3. Department of Materials Science and Engineering, National Defense Academy, 1-10-20 Hashirimizu, Yokosuka 239-8686, Kanagawa, Japan