Liu, Jinxiang
Deng, Qiliang
Tao, Dingyin
Yang, Kaiguang
Zhang, Lihua
Liang, Zhen
Zhang, Yukui
Article History
Received: 17 March 2014
Accepted: 9 June 2014
First Online: 30 June 2014
Competing interests
: The authors declare no competing financial interests.