1. School of Materials & Mineral Resources; Xi'an University of Architecture and Technology; No.13, Yanta Road Xi'an Shaanxi 710055 P.R. China
2. Department of Chemistry-Ångström; Uppsala University; Box 523 SE-751 20 Uppsala Sweden
3. Graduate School of Life Science and Systems Engineering; Kyushu Institute of Technology; 2-4 Hibikino, Wakamatsu Kitakyushu, Fukuoka 808-0196 Japan