作者机构:[1]Department of Applied Mathematics and Physics, Air Force Engineering University, Xi'an 710051, P. R. China, [2]Department of Mathematics, Yuncheng College, Yuncheng 044000, Shanxi Province, P. R. China, [3]Department of Mathematics, Shanghai University, Shanghai 200444, P. R. China
相关基金:Project supported by the National Natural Science Foundation of China (Nos. 10531030, 10701053), and the Natural Science Foundation of Shanxi Province of China (No. 2005Z010)