Funding for this research was provided by:
National Natural Science Foundation of China (61603009)
Beijing Natural Science Foundation (4182007)
National Natural Science Foundation of China (61533002)
Rixin Scientist Foundation of Beijing University of Technology (2017-RX(1)-04)
Article History
First Online: 4 January 2019
Compliance with ethical standards
:
: The authors declare that they have no conflict of interest.
: This article does not contain any studies with human participants or animals performed by any of the authors.