Funding for this research was provided by:
National Natural Science Foundation of China ((Nos. 71701001, 71771001, 71301001, 71371011, 71501002))
Provincial Natural Science Research Project of Anhui Colleges (KJ2015A379)
Anhui Provincial Philosophy and Social Science Planning Youth Foundation (AHSKQ2016D13)
The Doctoral Scientific Research Foundation of Anhui University
The Scientific Research Foundation of Hebei Education Department (QN2017060)
Article History
Received: 6 July 2016
Accepted: 22 January 2018
First Online: 12 February 2018
Compliance with Ethical Standards
: This manuscript has not been published in whole or in part elsewhere, which has also not currently being considered for publication in another journal. All authors have been personally and actively involved in substantive work leading to the manuscript, and will hold themselves jointly and individually responsible for its content.
: The authors declare that they have no conflict of interest.