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Biomedical subjects

Philip J Bos

Publications and source records attributed to Philip J Bos.

2 recordsLinked to original sources
PubMed2003

Fast Q-tensor method for modeling the dynamics of defects in a liquid crystal director field.

A fast Q-tensor method, which can model the defect dynamics in a liquid crystal director field, is presented. Conceptually based on the Oseen-Frank approach, we have added temperature energy density terms in addition to the strain energy terms, and an improved normalization method for fast calculations. The method is more compact and allows a larger time step than previous methods. The method is used to model the defect dynamics occurring during the topological state change from a splay to bend director field configuration.

Journal Article↗
PubMed2002

Multispectrum, spatially addressable polarization interference filter.

We review current synthesis techniques for generating and improving birefringent filters. The relationship between wave-plate orientation and the resulting spectral output is shown to be that of a simple Fourier transform. By using this relationship and starting from the fan Solc configuration, we easily generated plate orientations providing lower sidelobe levels and improved finesse. We outline a method by which filters can be constructed to provide from 0 to 100% of the desired passband in a continuous fashion. Such a filter can be stacked to allow rapid control of any number of passbands and is shown, as an example in a novel design employing super-twisted nematic liquid crystal elements, to control a maximum of three color bands.

Journal Article↗