1. State Key Laboratory of Rare Earth Resource Utilization; Changchun Institute of Applied Chemistry; Chinese Academy of Sciences; Changchun 130022 P. R. China
2. University of Chinese Academy of Sciences; Beijing 100049 P. R. China
3. Key Laboratory of Superlight Materials and Surface Technology; Ministry of Education; College of Material Sciences and Chemical Engineering; Harbin Engineering University; Harbin 150001 P. R. China