Funding for this research was provided by:
National Natural Science Foundation of China (51772246, 51272210, 50902112, U1737209)
Program for New Century Excellent Talents in University (NCET-13-0474)
Fundamental Research Funds for the Central Universities (3102017jg02001, 3102018jcc002)
Article History
Received: 22 October 2018
Revised: 13 December 2018
Accepted: 27 December 2018
First Online: 10 January 2019
Compliance with ethical standards
:
: The authors declare that they have no conflict of interest.