1. Jibei Electric Power Research Institute, State Grid Jibei Electric Power Co., Ltd., North China Electric Power Research Institute Company Limited, Beijing 100045, P. R. China
2. Beijing Key Laboratory of Function Materials for Molecule & Structure Construction, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, P. R. China
3. State Grid Jibei Electric Power Co., Ltd., Tangshan Power Supply Company, Tangshan 063000, P. R. China