1. Department of Polymer Science and Engineering, University of Science and Technology Beijing, Beijing, P. R. China
2. College of Material and Chemical Engineering, University of Hainan, Hainan, P. R. China
3. State Key Laboratory of Advanced Transmission Technology, Global Energy Interconnection Research Institute, Beijing, P. R. China
4. Life Evaluation and Management Technology of Nonmetal Materials Lab, CGN National R and D Center, Suzhou, China