Biomedical subjects
Publications and source records attributed to Reimar Finken.
The adhesion of microcapsules to an attractive contact potential is studied theoretically. The axisymmetric shape equations are solved numerically. Beyond a universal threshold strength of the potential, the contact radius increases in proportion to the square root of the strength. Scaling functions for the corresponding amplitudes are derived as a function of the elastic parameters.
We establish a rigorous time-dependent density functional theory of classical fluids for a wide class of microscopic dynamics. We obtain a stationary action principle for the density. We further introduce an exact practical scheme, to obtain hydrodynamical effects in density evolution, that is analogous to the Kohn-Sham theory of quantum systems. Finally, we show how the current theory recovers existing phenomenological theories in an adiabatic limit.
We investigate the system of D-dimensional hard spheres in D-dimensional space, where D>3. For the fluid phase of these hyperspheres, we generalize scaled-particle theory to arbitrary D and furthermore use the virial expansion and the Percus-Yevick integral equation. For the crystalline phase, we adopt cell theory based on elementary geometrical assumptions about close-packed lattices. Regardless of the approximation applied, and for dimensions as high as D=50, we find a first-order freezing transition, which preempts the Kirkwood second-order instability of the fluid. The relative density jump increases with D, and a generalized Lindemann rule of melting holds. We have also used ideas from fundamental-measure theory to obtain a free energy density functional for hard hyperspheres. Finally, we have calculated the surface tension of a hypersphere fluid near a hard smooth (hyper-)wall within scaled-particle theory.