1. School of Materials Science and Chemical Engineering Ningbo University Ningbo Zhejiang 315211 P. R. China
2. Department of Applied Chemistry Hiroshima University 1-4-1 Kagamiyama Higashi Hiroshima 739-8527 Japan
3. Faculty of Engineering Kanagawa University Rokkakubashi, Kanagawa-ku Yokohama-shi Kanagawa 221-8686 Japan