1. State Key Laboratory of Electrical Insulation and Power EquipmentXi'an Jiaotong UniversityXi'anPeople's Republic of China
2. College of Materials Science and Engineering, Qingdao University of Science and TechnologyQingdaoPeople's Republic of China
3. School of Electrical and Electronic Engineering, Harbin University of Science and TechnologyHarbinPeople's Republic of China