ShanghaiInstituteofAppliedMathematicsandMechanics;
CollegeofScience;
ShanghaiUniversity;
Shanghai200072;
China//DepartmentofMathematicsandInformationScience;
YantaiUniversity;
Yantai264005;
China;
ShanghaiInstituteofAppliedMathematicsandMechanics;
CollegeofScience;
ShanghaiUniversity;
Shanghai200072;
China;