Feng, Xiaozhou
Song, Yi
Liu, Jianxin
Wang, Guohui
Funding for this research was provided by:
the National Natural Science Youth Fund of China (61102144)
The Shandong Provincial Natural Science Foundation of China (No.ZR2015AQ001)
The Shaanxi Province Department of Education Fund (18JK1353)
The principal fund of Xi'an Technological University (XAGDXJJ17028)
Article History
Received: 21 April 2018
Accepted: 30 July 2018
First Online: 6 September 2018
Competing interests
: The authors declare that there are no competing interests regarding the publication of this paper.