报告时间：2017年9月27日（星期三）15:00-16:00

报告地点：格物楼二楼 学术报告厅

报 告 人：Wilfred T Tysoe 教授

工作单位：美国威斯康星大学密尔沃基校区

举办单位：机械工程学院

报告人简介：

Tysoe教授1982年在英国剑桥大学获得博士学位，1982-1984年在美国加州大学伯克利分校从事博士后研究，1984年开始就职于美国威斯康星大学密尔沃基校区任助理教授，1990年起任终身教授，2007年起获聘威斯康星大学杰出教授（Distinguished Professor）。他的研究内容包括超高真空环境下的摩擦学、表面化学，以及微观摩擦学研究。 他发表了近300篇同行评审的学术论文，作过300余场学术报告。 他是机械摩擦学领域国际著名期刊《Tribology Letters》创办人，1994-2017年担任《Tribology Letters》期刊主编。

Biography of Professor Wilfred T Tysoe:

Wilfred T Tysoe is a Distinguished Professor at the University of Wisconsin-Milwaukee. He received his B.Sc. in Chemical Physics at the University of Manchester, an M.Sc degree at the University of Sydney, Australia and obtained his Ph.D. degree in 1982 in Physical Chemistry at the University of Cambridge, England and worked as a post-doctoral researcher at the University of California, Berkeley, before moving to his present position at the University of Wisconsin-Milwaukee in 1984. His research interests focus on chemical properties at surfaces with particular emphasis on understanding catalytic reactions both in ultrahigh vacuum and under realistic conditions and in the area of tribology to understand the interplay between lubricant chemistry and the resulting frictional and wear properties of reactively formed tribological films. He is a founding Editor of Tribology Letters and co-writes the “Cutting Edge” column in the STLE magazine, Tribology and Lubrication Technology. He has published almost 300 papers in scientific journals and presented over 300 talks.

Contact e-mail: wtt@uwm.edu

报告简介：

Perhaps the most difficult surface-science challenge is to monitor reaction pathways and kinetics at sliding solid-solid interfaces, in particular for opaque contacting materials. Optical techniques can be used to interrogate the interface when one of the contacting surfaces is transparent, but they are often not sensitive to the first monolayer. Strategies for measuring reaction pathways and their kinetics for well-defined surfaces in ultrahigh vacuum (UHV) are described using the example of sliding-induced decomposition of adsorbed methyl thiolate species, formed by exposure to dimethyl disulfide, on copper. Surface science experiments show that methyl thiolates are stable up to ~425 K on copper, but decompose during rubbing; the effect of the external force is to lower the reaction activation barrier so that it proceeds at room temperature. The surface reaction products can be monitored immediately after sliding in UHV using surface spectroscopies (for example, Auger spectroscopy). However, the reaction kinetics can also be monitored in situ first, by measuring the gas-phase species evolved as a function of the number of times the surface is rubbed, where methane and ethane are detected and second, by measuring the change in friction force due to the evolution of the nature of the species present on the surface. This allows the elementary steps in the tribofilm formation pathway to be identified and their rates measured.