1. School of Printing and Packing Engineering; Beijing Institute of Graphic Communication; 1 Xinghua Avenue (Band Two), Daxing Beijing 102600 P.R. China
2. Department of Applied Chemistry; Faculty of Science and Engineering, Saga University; Honjo-machi 1 Saga 840-8502 Japan
3. School of Materials Science and Engineering; Shannxi Normal University; Xi'an 710062 Shannxi P.R. China
4. Department of Chemistry; University of Hull; Cottingham Rd Hull HU6 7RX UK