基金Supported by Program for New Century Excellent Talents in University (NCET-04-0283), the Funds for Creative Research Groups of China (60521003), Program for Changjiang Scholars and Innovative Research Team in University (IRT0421), the State Key Program of National Natural Science of China (60534010), National Natural Science Foundation of China (60674021), the Funds of Doctoral Program of Ministry of Education of China (20060145019), and the 111 Proiect (B08015)