Supported by National Natural Science Foundation of China (10301010);Science and Technology Commission of Shanghai Municipality (04JC14031);National Natural Science Founda-tion of Anhui (2006KJ256B)
Supported by the National Natural Science Foundation of China(10301010),Scienceand Technology Commission of Shanghai Municipality(04JC14031),and National Natural ScienceFoundation of Anhui(2006KJ256B)