partly supported by the NSF(11271090,11171184,11001057);the Tianyuan Youth Fund of the NSF of China(11326083);Shanghai University Young Teacher Training Program(ZZSDJ12020);Innovation Progrom of Shanghai Municipal Education Commission(14YZ164);the NSF of Guangdong Province(S2012010010121);Projects13XKJ01 from the Leading Academic Discipline Project of Shanghai Dianji University;the Visiting Scholar Program of Department of Mathematics and Statistics at Curtin University of Technology