基金supported by the National Natural Science Foundation of China under Grant No.60962006 and the National Natural Science Foundation of Ningxia under Grant No.NZ0848
基金Supported partly by the Key Project of Provincial Natural Scientific Research Fund from the Educational Bureau of Anhui Province of China(KJ2007A087)National Natural Science Foundation of China(60475017)+1 种基金National Basic Research (973) Program of China (2004CB318108)Natural Science Foundation of Anhui Province of China (090412045,090412261X)