1. School of Chemical Engineering, Huaihai Institute of Technology, Lianyungang 222005, P. R. China
2. College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, P. R. China
3. SORST, Japan Science and Technology Agency (JST), 4-1-8 Kawaguchi Center Building, Kawaguchi, Saitama 332-0012