1. Department of Applied Chemistry and Research Institute for Science and Engineering, Waseda University, Tokyo, 169-8555, Japan
2. State Key Laboratory of Electrical Insulation and Power Equipment, School of Electrical Engineering, Xi’an Jiaotong University, Xi’an, 710049 Shaanxi, People’s Republic of China
3. Department of Electrical Engineering and Bioscience, Waseda University, Tokyo, 169-8555, Japan