报告题目：

Contact, Friction and Wear at the Nanoscale

 报告人:               Prof. Yong-Wei Zhang

Institute of High Performance Computing, Singapore, 13863

时间：2014年12月25日(周四)  9: 00              

地点：中国科学院力学研究所主楼344会议室

报告摘要：

Using molecular dynamics simulations, we show that a probing tip using a short capped single-walled carbon nanotube is able to capture the frictional characteristics and faithfully resolve the graphene lattice through the measurements of oscillatory lateral force or normal force. By averaging the oscillatory lateral force and normal force along the tip moving path, we extract the friction coefficient. It is found that the friction coefficient decreases with increasing both the initial tip–surface distance and the number of graphene layer. The underlying energy dissipation arises from the periodical acceleration–deceleration of the tip, causing the conversion of kinetic energy into thermal energy. We also study the interaction of the tip with a single-layer graphene containing a vacancy or Stone–Thrower–Wales defect, and reveal that the change in lateral and normal forces can be used to differentiate these defects. The present study demonstrates that a short single-walled capped nanotube can serve as an ideal candidate for high-resolution surface probing.

报告人简介：

Dr Zhang completed his doctorate in Aerocraft Design at the Northwestern Polytechnical University in 1992. After his Ph.D study, he spent three years as Assistant Research Fellow and Associate Research Fellow at the Institute of Mechanics, Chinese Academy of Sciences. In 1996, he joined the Division of Engineering at Brown University as Research Associate. In 1998, Dr. Zhang moved to Singapore to join the Institute of Materials Research and Engineering. In 2001, Dr. Zhang joined the Department of Materials Science and Engineering at National University of Singapore. After nine-year academic life, he joined the Institute of High Performance Computing, Singapore in 2010. Since then he has been Principal Scientist and Department Director for Engineering Mechanics at the Institute of High Performance Computing, Singapore. He has published over 130 refereed journal papers in the areas of mechanical properties of nanomaterials and nanostructures, morphological evolution in nanostructure growth and mechanical properties of biological and bioinspired materials. His current research interests focus on modeling and simulations of mechanical properties of graphene, growth of quantum dots and instability in soft materials.