Cui, Shumao
Pu, Haihui
Wells, Spencer A.
Wen, Zhenhai
Mao, Shun
Chang, Jingbo
Hersam, Mark C.
Chen, Junhong
Article History
Received: 9 November 2014
Accepted: 11 September 2015
First Online: 21 October 2015
Competing interests
: The authors declare no competing financial interests.