[1] Zunyi Normal Coll, Dept Phys, Zunyi 563002, Guizhou, Peoples R China
[2] Jinling Inst Technol, Coll Sci, Nanjing 211169, Jiangsu, Peoples R China
[3] Linyi Univ, Sch Phys & Elect Engn, Linyi 276005, Shandong, Peoples R China
[4] Southeast Univ, Sch Mat Sci & Engn, Nanjing 211189, Jiangsu, Peoples R China
[5] Southeast Univ, Sch Mech Engn, Nanjing 211189, Jiangsu, Peoples R China