1. School of Electric Power Engineering, South China University of Technology, Guangzhou, Guangdong, China
2. College of Electrical and Electronic Engineering, Shandong University of Technology, Zibo, Shandong, China
3. Institute of Advanced Technology, Chinese Academy of Sciences, Institute of Biomedical and Health Engineering, Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen, Guangdong, China