作者机构:[1]School of Science, China University of Mining and Technology, Xuzhou 221008, China, [2]School of Mathematical Sciences, Research Center for Nonlinear Sciences, Fudan University, Shanghai 200433, China
相关基金:Supported by the National Natural Science Foundation of China under Grant Nos. 61203304, 61203055 and 10901145, and the Funda- mental Research Funds for the Central Universities under Grant Nos. 2011QNA26, 2010LKSX04, and 2010LKSX01