国家自然科学基金60778037.50772059,11004123;高等学校全国优秀博士学位论文专项资金200539;山东省自然科学基金ZR2009GQ007;国家博士后科研基金20100470040;山东省中青年科学家奖励基金BS2011CL025资助项目 The project was supported by the National Natural Science Foundation of China60778037,50772059,1 1 004123;Foundation of National Excellent Doctoral Dissertation of China200539;Natural Science Foundation of Shandong Province,ChinaZR2009GQ007;China Postdoctoral Science Foundation20100470040;Youth Scientist Fund of Shandong Province,ChinaBS2011CL025