Zhang, Jianke
Yin, Luyang
Zhou, Chang
Funding for this research was provided by:
the Science Plan Foundation of the Education Bureau of Shaanxi Province (2013JK 1130)
Article History
Received: 23 November 2017
Accepted: 7 February 2018
First Online: 17 February 2018
Competing interests
: The authors declare that they have no competing interests.
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