1. a Department of Materials Science and Technology, Faculty of Engineering Gifu University Yanagido Gifu 501-1193 Japan
2. b Research Institute for Advanced Science and Technology Osaka Prefecture University Gakuen-Cho 1-2, Sakai Osaka 599-8570 Japan
3. c Yokohama Research Center Mitsubishi Chemical Co. Kamoshida 1000, Aoba Yokohama 227-8502 Japan