1. School of Applied
Physics and Materials, Wuyi University, Jiangmen, Guangdong 529020, P. R. China
2. State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
3. Instrumentation Analysis and Research Center, Fuzhou University, Fuzhou, Fujian 350002, P. R. China