[1] Taiyuan Univ Technol, Coll Mat Sci & Engn, Taiyuan 030024, Shanxi, Peoples R China
[2] Lanzhou Univ, Coll Chem & Chem Engn, Lanzhou 730000, Gansu, Peoples R China
[3] Lanzhou Univ, Sch Phys Sci & Technol, Lanzhou 730000, Gansu, Peoples R China
[4] Key Lab Electromagnet Protect Mat & Technol Shanx, Taiyuan 030006, Shanxi, Peoples R China