Funding for this research was provided by:
National Natural Science Foundation of China (61502180)
Natural Science Foundation of Guangdong Province (2014A030310238)
Pearl River S&T Nova Program of Guangzhou (201605121512554)
JSPS KAKENHI (JP16K00117, JP15K15976)
National Natural Science Foundation of China (61272067)
KDDI Foundation
Article History
Received: 24 February 2017
Revised: 3 June 2017
Accepted: 8 November 2017
First Online: 14 February 2018