Funding for this research was provided by:
National Key Basic Research Program (973 program) (2012CB315905)
National Natural Science Foundation of China (CN) (61370190)
Natural Science Foundation of Jilin Province (CN) (61472029, 61472429)
Natural Science Foundation of China (61472083)
Beijing Natural Science Foundation (4132056, 4122041)
Research Funds of Renmin University of China (14XNLF02)