1. School of Mathematics and Statistics; Northeast Normal University; Changchun 130024 China
2. Department of Mathematics and Statistics; McMaster University; Hamilton ON L8S 4K1 Canada
3. Nonlinear Analysis and Applied Mathematics (NAAM)-Research Group; Department of Mathematics, Faculty of Science, King Abdulaziz University; Jeddah 121589 Saudi Arabia
4. College of Science; China University of Petroleum (East China); Qingdao 266580 China