1. School of Energy and Power Engineering, Changsha University of Science & Technology, Changsha, Hunan 410114, China
2. Key Laboratory of Energy Efficiency and Clean Utilization, The Education Department of Hunan Province, Changsha University of Science & Technology, Changsha, Hunan 410114, China
3. Hunan Rare Earth Metal Material Research Institute, Institute of Rare Earth Light Alloys, Changsha, 410126, China