基金Supported by the Funds of Ministry of Education of China for PhD Units under No. 200201410L3the National Natural Science Foundation of China under project grant No.10471015
基金Supported by the Natural Science Foundation of Henan Province of China(0111050200) Natural Science Foundation of Education Committee of Henan Province of China(2003110003)the Science Foundation of Henan University of Science and Technology(2003ZY03)