Li, Junjie
Zhang, Weixia
Chung, Ting-Fung
Slipchenko, Mikhail N.
Chen, Yong P.
Cheng, Ji-Xin
Yang, Chen
Article History
Received: 3 February 2015
Accepted: 26 June 2015
First Online: 23 July 2015
Competing interests
: The authors declare no competing financial interests.