1. Key Laboratory of Traffic Safety on Track, Ministry of Education, School of Traffic & Transportation Engineering, Central South University, Changsha, Hunan, P.R. China;
2. Joint International Research Laboratory of Key Technologies for Rail Traffic Safety, Changsha, Hunan, P.R. China;
3. National & Local Joint Engineering Research Center of Safety Technology for Rail Vehicle, Changsha, Hunan, P.R. China;
4. Nyheim Plasma Institute, Drexel University, Camden, NJ, USA