作者机构:[1]School of Mathematics and Statistics, Hebei University of Economics & Business, Shijiazhuang 050061, P. R. China, [2]Institute of Applied Mathematics, Shijiazhuang Mechanical Engineering College, Shijiazhuang 050003, P. R. China
相关基金:Supported by the National Natural Science Foundation of China (Grant Nos. 10671209; 10926064).