supported by the National Natural Science Foundation of China(No.30970972;30800329);the Science Program of Central China Normal University(No.CCNU09B01009)
This work was supported by grants fromthe National Natural Science Foundation of China(No.30470564,30670695);an international joint grantfromthe NSFC;the Russian Foundation of Basic Research(NSFC:No.30611120056;RFBR:No.05-04-39008)