1. Department of Mechanical Engineering, College of Engineering, University of Kentucky, Lexington, Kentucky 40506, United States
2. Key Lab for Robot & Welding Automation of Jiangxi Province, Mechanical & Electrical Engineering School, Nanchang University, Nanchang 330031, P.R. China
3. Department of Chemistry, College of Arts & Sciences, University of Kentucky, Lexington, Kentucky 40506, United States