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Barry Cox
School of Mathematics & Applied Statistics, University of Wollongong
Mechanics and geometry of carbon nanostructures
Wednesday 16th April 14:05-14:55pm,
Eastern Avenue Lecture Theatre.
Carbon nanostructures occur in many familiar forms such as cylinders,
spheres and spheroids, and therefore mathematical modeling can be a
useful tool for solving problems in nanotechnology. There are many
diverse applications for modeling, such as nano-oscillating devices,
drug delivery and memory devices, to name just a few. Two different
approaches to modeling carbon nanostructures are presented in this
seminar. Firstly, the conventional theory for carbon nanotubes is
introduced and while it is readily applicable in many cases, there are
short-comings in the case of very small radius nanotubes which exhibit
curvature effects which are not captured by the conventional theory. A
new model is then described that is based on only geometric
considerations, but which captures the effects of curvature and can also
be justified with an energy minimization argument. The new model
provides considerable insight into discrete nanotube structure, and the
results are shown to be entirely in agreement with computational
studies. Essentially, the new model provides the correct polyhedral
structure for a cylinder, which surprisingly enough seems not to have
been previously given in the mathematical literature. The second
modeling approach is a continuous formulation of the van der Waals
interaction energy between nanostructures. This approach is used to
model molecules as a surface distribution of atoms and then calculate
the interaction between molecules by formal integration over the two
surfaces in question. In this area a number of integrals are evaluated
in closed analytical forms, and which have not previously appeared in
the literature. The analytical evaluation is particularly important when
it is necessary to obtain a large numerical landscape in situations when
it would be prohibitive to use a purely computational approach. Finally,
the notions of suction and acceptance energies are introduced which give
a framework for evaluating different oscillating systems.
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