1. Graduate School of Materials Science, Nara Instituted of Science and Technology (NAIST), 8916‐5 Takayama, Ikoma, Nara 630‐0101, Japan, Fax: +81‐743‐72‐6089
2. Department of Applied Chemistry, Faculty of Engineering, University of Miyazaki, 1‐1 Gakuen Kibanadai‐Nishi, Miyazaki 889‐2155, Japan