Uwe Hollerbach

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In an electrostatic problem with nonuniform geometry, a charge Q in one region induces surface charges [called dielectric boundary charges (DBC)] at boundaries between different dielectrics. These induced surface charges, in return, exert a force [called dielectric boundary force (DBF)] on the charge Q that induced them. The DBF is often overlooked. It is(More)
We simulate sodium chloride currents through the gramicidin A channel using the spectral element method to solve the three-dimensional Poisson–Nernst– Planck (PNP) equations. Using the spectral element method, we are able to simulate the entire channel, plus large enough portions of the lipid bilayer and baths to ensure that all boundary conditions are(More)
Gramicidin A (Wallace, B. A. Gramicidin channels and pores. Annu. Rev. Biophys. Biophys. Chem. 1990, 19, 127-157) is a neutral polypeptide that acts as a channel to allow ions to cross otherwise impermeable membranes. We compute sodium chloride currents through the gramicidin A channel using the spectral element method to solve the three-dimensional(More)
The ionic current flowing through a protein channel in the membrane of a biological cell depends on the concentration of the permeant ion, as well as on many other variables. As the concentration increases, the rate of arrival of bath ions to the channel's entrance increases, and typically so does the net current. This concentration dependence is part of(More)
A comprehensive three-dimensional simulation model for non-planar substrate lithography is presented. Matching substrate as well as standing wave effects are examined. The projection printing is simulated using Hopkins' results and the exposure model is solved using spectral element discretizations of the nonlinear wave equation coupled with the rate(More)
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