1. CGNPC Uranium Resources Co. Ltd., Building 5, Yard 16, Changxing Road, Fengtai District, Beijing 100072, P. R. China
2. School of Materials Science and Engineering, Tianjin University, Tianjin, P. R. China
3. School of Automation, Beihang University, Building 5, Yard 16, Changxing Road, Fengtai District, Beijing 100072, P. R. China