1. State Key Laboratory of Polymer Physics and Chemistry; Changchun Institute of Applied Chemistry; Chinese Academy of Sciences; No. 5625, Renmin Street Changchun 130022 China
2. Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province School of Chemistry and Chemical Engineering; Lanzhou University; Lanzhou 730000 P. R. China
3. University of Chinese Academy of Sciences; Changchun Branch; Changchun 130022 China
4. LPCNO; University of Toulouse, INSA Toulouse; 135, avenue de Rangueil Toulouse cedex 31077 France