1. Professor, Changsha Univ. of Science and Technology, Changsha, Hunan 410114, China (corresponding author).
2. Professor, Changsha Univ. of Science and Technology, Changsha, Hunan 410114, China.
3. General Manager, GuangDong Qinglian Expressway Co., Ltd., Qingyuan, Guangdong 511515, China.