1. Key Laboratory of Leather Chemistry and Engineering of Ministry of Education; Sichuan University; Chengdu 610065 P. R. China
2. ISM; Universite Bordeaux; UMR CNRS N 5255 33405 Talence Cedex France
3. Facultad de Quimica de San Sebastian; Universidad del Pais Vasco; Apdo 1072 20080 San Sebastian Spain
4. Science and Technology on Surface Physics and Chemistry Laboratory; PO Box 718-35 Mianyang 621907 Sichuan P. R. China