Dr. Xin-Ping Zhang should be noted as co-corresponding author with Dr. Ke Zhao. Dr. Zhang’s email address is: mexzhang@scut.edu.cn.There are errors in the Funding section. The correct funding information is as follows: Funding for this work came from the Natural Science Foundation of China (No. 50871039, http://www.nsfc.gov.cn/) and the Guangdong Provincial Natural Science Foundation (Key Grant No. S2013020012805, http://www.gdstc.gov.cn/).