This is a brief scheme of how AFM works. It uses a soft cantilever with a sharp tip mounted at the end to "touch" the surface. A localized interacting force between the tip and the specimen surface is responsible for the image contrast. In the contact mode, a piezo-tube is used to keep the repulsive interaction between the specimen and the tip a constant by means of a feedback loop. In raster-scanning the tip relative to the specimen, the vertical movement of the piezo-tube maps out the surface topography.
Dr. Yang's main interests concentrate on biophysics in lower dimensions. One area involves in situ high-resolution structural studies of membrane proteins using state-of-the-art atomic force microscopy, in which the goal is to fully use the power of AFM to obtain nm-resolution structure of membrane proteins. One area aims at an understanding of the 2-D condensation of DNA on cationic membranes, which may have potential impact in our understanding of the packing of genetic materials in higher organisms and in helping to find efficient means in gene delivery trials. A related area is to study the self-assembly of biomaterials under various conditions, by detecting the assembled structure at high resolution in combination with exploring the dynamic aspects and thermal equilibrium phases of these systems.
Dr. Yang has a B.S. degree in Physics from Nanjing University and M.S. and Ph.D. degrees in Physics from Princeton University. He joined the University of Vermont in 1994 from a position as Research Assistant Professor at the University of Virginia.