1. School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, P. R. China
2. CPE Lyon, 43 Boulevard du 11 Novembre 1918, 69622 Villeurbanne, France
3. Shanghai Key Laboratory of Electrical Insulation and Thermal Aging, Shanghai Jiao Tong University, 800 Dongchuan Road, Sthanghai 200240, P. R. China