1. Department of Dermatology; Xi'an Jiaotong University; Xi'an 710049 China
2. Center of Plasma Biomedicine; State Key Laboratory of Electrical Insulation and Power Equipment; Xi'an Jiaotong University; Xi'an 710049 China
3. School of Electrical Engineering; Xi'an Jiaotong University; Xi'an 710049 China
4. Center for Bioelectrics; Old Dominion University; Norfolk VA 23508 U.S.A