Surface rouglmess

Plenary 13. Andreas Otto, e-mail address otto rz.imi-duesseldorf.de (SERS). A survey of problems and models that underlie the SERS effect, now two decades old. Understanding the role of surface rouglmess in the enliancement. 

The values of Oy and vary with tlie turbulent structure of the atmosphere, the heiglit above the surface, tlie surface rouglmess, the sampling time over wluch tlie concentration is to be estimated, tlie wind speed, and tlie distance from tlie source. For tlie parameter values tliat follow, the sampling time was originally assumed to be about 10 minutes, tlie height to be tlie lowest several hmidred meters of tlie atmosphere, and tlie surface to be relatively open country. Tlie parameters are estimated from tlie stability of the atmosphere,... 

Many investigators have studied the effects of the solid-surface texture on friction, mainly in full-film EHL or mixed lubrication where the hydrodynamic action of the fluid plays a role [1-3]. The consensus on the effect of surface rouglmess orientation on friction is that transversely oriented roughness results in a much thicker hydro namic film than does longitudinally oriented roi hness. However, the effect of si ce texture in the performance of lubricants in a boundary lubrication regime is much less understood, and the difference between mixed and boundary lubrication is basically unclear. The reason for friis insufficient understanding is hydrodynamic action, including micro-EHL, is not well understood and we cannot yet predict where it should appear. More research on mixed lubrication is necessary [4]. 

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