Jiang, Xiaoqing
Yu, Ze
Zhang, Yuchen
Lai, Jianbo
Li, Jiajia
Gurzadyan, Gagik G.
Yang, Xichuan
Sun, Licheng
Article History
Received: 6 December 2016
Accepted: 10 January 2017
First Online: 13 February 2017
Competing interests
: The authors declare no competing financial interests.