1. Chongqing University, State Key Laboratory of Power Transmission Equipment and System Security and New Technology, Chongqing 400044, China
2. Oceanography College, Shanwei Polytechnic, Shanwei 516600, China
3. Department of Public Basis, Zhaoqing Medical College, Zhaoqing 526020, China
4. Shaanxi Railway Institute, Weinan 714000, China