Funding for this research was provided by:
Natural Science Foundation of Beijing Municipality (2132126)
National Natural Science Foundations of China (51221163)
National Natural Science Foundations of China (51331001)
National Basic Research Program of China (2012CB619404)
Beijing Municipal Natural Science Foundation (2132126)
Article History
Received: 15 October 2015
Revised: 5 November 2015
Accepted: 8 November 2016
First Online: 20 December 2016