supported by the Tianjin Natural Science Foundation(08JCYBJC02200);the Keygrant Project of Chinese Ministry of Education(309009);the Natural Science Foundation of China(11171164)
Financial support from National Basic Research Program of China(973Program,2007CB814905);the National Natural Science Foundation of China(10871102);the Natural Science Foundation of Tianjin(08JCYBJC02200)
Supported by the Natural Science Foundation of Tianjin(08JCYBJC02200);the Natural Science Foundation of China(10871102);National Basic Research Program of China(973 Program) (2007CB814905)