1. 1School of Mathematics and Computer Science, Hubei University of Arts and Science, Xiangyang, Hubei, 441053, P.R. China; School of Mathematics and Statistics, Xi’an Jiaotong University, Xi’an 710049, P.R. China
2. 2School of Mathematics and Statistics, Wuhan University, Wuhan, Hubei 430072, P.R. China
3. 3College of Mathematics and System Sciences, XinJiang University, Urumqi 830046, P.R. China
4. 4Department of Mechanical Engineering, University of Texas at Dallas, Richardson, United States America