Growth and erosion of thin solid films

Thin films that are grown by the process of sputtering are, by and large, quite unlike the smooth, featureless structures that one might expect. In general, these films have a complicated surface morphology and an extended network of grooves and voids in their interiors. Such features can have a profound effect on the physical properties of a thin film. The surface irregularities and the bulk defects are the result of a growth instability due to competitive shadowing, an effect that also plays a role in geological processes such as erosion. For amorphous thin films, the shadow instability can be described by a remarkably simple model, which can be shown to reproduce many important observed characteristics of thin film morphology.     

The dynamics of the oceanic subtropical gyres

Recent theoretical advances in physical oceanography have produced plausible models for the structure of the circulation in the oceans' subtropical gyres. These theoretical ideas are reviewed and assessed in the light of present observational evidence. The dominant role of potential vorticity is emphasized in describing the strong interplay between three-dimensional distributions of density and velocity. In particular, the complementary processes of subduction and recirculation jointly act to shape the circulation pattern of the subtropical gyre.