基金The project supported by the National Natural Science Foundation of China (No.50532070,50472009,90201038,10474091)Foundation of Scientific Research of Henan University(No.06YBZR022)
基金This work supported by the Scientific Research Foundation from Henan University (No. 06YBZR007)the National NaturalScience Foundation of China (No.60576063)the PhD Project of the Chinese Education Ministry (No. 20050335036)