基金Supported by National Basic Research Program of China (973 Program) (2007CB814904), National Natural Science Foundation of China (10671112, 10701050), and Natural Science Foundation of Shandong Province (Z2006A01)
基金National Natural Science Foundation of P. R. China (50477042)Ph. D. Programs Foundation of Ministry of Education of P.R.China (20040422052)the Natural Science Foundation of Shandong Province (Z2004G04)