1. School of Applied Physics and Materials, Wuyi University, Jiangmen 529020, P.R. China
2. School of Rail Transportation, Wuyi University, Jiangmen 529020, P.R. China
3. Joint Key Laboratory of the Ministry of Education, Institute of Applied Physics and Materials Engineering, University of Macau, Avenida da Universidade, Taipa, Macau 999078, P.R. China