Funding for this research was provided by:
National Key Research and Development Plan of China (2016YFE0202100)
Key Program of NSF China (U1805241)
China Scholarship Council (201806315023)
President Fund of Xiamen University (20720190105)
Article History
Received: 16 April 2019
Revised: 23 October 2019
Accepted: 10 January 2020
First Online: 24 January 2020