[1] CRSC Res & Design Inst Grp Co Ltd, Beijing 100071, Peoples R China
[2] Southwest Jiaotong Univ, Key Lab Magnet Suspens Technol & Maglev Vehicle, Minist Educ, Chengdu 610031, Peoples R China
[3] Southwestern Inst Phys, Chengdu 610041, Peoples R China
[4] Northwest Inst Nonferrous Met Res, Xian 710016, Peoples R China
[5] Huazhong Univ Sci & Technol, State Key Lab Adv Electromagnet Engn & Technol, Wuhan 430074, Peoples R China