1. School of Mathematics and Physics of Science and Engineering, Anhui University of Technology, Maanshan 243002, China
2. Physics Department, University of Massachusetts Lowell, Lowell, Massachusetts 01854, USA
3. School of Chemistry and Chemical Engineering, Anhui University of Technology, Maanshan 243002, China
4. Urological Department, The Fourth Affiliated Hospital of Anhui Medical University, Hefei 230022, China