国家自然科学基金项目40971091;国家社会科学基金重点项目11AZD04;国家科技支撑计划课题2011BAC09B07;国家自然科学基金重点项目U1202232 [National Natural Science Foundation of China,No.40971091;Key Project of National Social Science Foundation of China,No.11AZD04;National Science and Technology Support Program,No.2011BAC09B07;Key Project of National Natural Science Foundation of China,No.U1202232]