1. Department of Mathematics
and Physics, Chongqing University of Posts and Telecommunications, 2 Chongwen Road, Chongqing 400065, China
2. State Key Laboratory
of Luminescence and Applications, Changchun Institute of Optics, Fine
Mechanics and Physics, Chinese Academy of Sciences, 3888 Eastern
South Lake Road, Changchun 130033, China
3. Graduate School of Chinese Academy of Sciences, Beijing 100039, China
4. School
of Science, Chongqing University of Technology, 69 Hongguang Street, Chongqing 400054, China