supported by Projects in the National Science and Technology Pillar Program in the Eleventh Five-year Plan Period(2006BAI05A07);National High-Tech Research and Development Program of China(863 Program)(2006AA02A408);Major State Basic Research Development Program of China(973 Program)(2006cb500700);National Key Technologies Research and Development Program of China(2004BA720A03);National Natural Science Foundation of China(30400262,30470619,30710303061,30871354,30971585);New Century Excellent Talents in University of Department of Education;Key Project of Natural Science Foundation of Hunan Province(08JJ3048);Graduate Degree Thesis Innovation Foundation of Central South University(2008yb030)