Concept

Polytope régulier

Publications associées (75)

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Plasmon resonances in nanowires with a non-regular cross-section

Olivier Martin

We investigate numerically the spectrum of plasmon resonances for metallic nanowires with a non-regular cross-section in the 20-50 nm range. After briefly recalling the physical properties of metals at optical frequencies, we point out the intrinsic diffic ...

2003

Adaptive control of a G. xylinus fed-batch fermentation using in situ mid-IR spectroscopy

Urs von Stockar, Sergio Valentinotti, Martin Rhiel, Henri Kornmann

Bacterial exopolysaccharides (EPS) have unique rheol. properties due to their high purity and regular structure. Thus, the food industry frequently uses EPS as thickening, gelling or stabilizing agents. The strain Gluconacetobacter xylinus I 2281 is capabl ...

2003

Extended convex hull

Thomas Liebling

In this paper we address the problem of computing a minimal representation of the convex hull of the union of k H- polytopes in . Our method applies the reverse search algorithm to a shelling ordering of the facets of the convex hull. Efficient wrapping is ...

2001

Non-regularly shaped plasmon resonant nanoparticle as localized light source for near-field microscopy

Olivier Martin

We study numerically two-dimensional nanoparticles with a non-regular shape and demonstrate that these particles can support many more plasmon resonances than a particle with a regular shape (e.g. an ellipse). The electric field distributions associated wi ...

2001

Warped compactification on Abelian vortex in six dimensions

We consider the possibility of localizing gravity on a Nielsen-Olesen vortex in the context of the Abelian Higgs model. The vortex lives in a six-dimensional space-time with negative bulk cosmological constant. In this model we find a region of the paramet ...

2001

Influence of the cross section and the permittivity on the plasmon-resonance spectrum of silver nanowires

Olivier Martin

We investigate the plasmon resonances for silver nanowires with a non-regular cross section. To study the relationship between the cross section and the spectrum of the plasmon resonances, we consider cross sections evolving from a rectangular shape to a t ...

2001

Gomory-chvatal cutting planes and the elementary closure of polyhedra

Friedrich Eisenbrand

The elementary closure P'; of a polyhedrom P is the intersection of P with all its Gomory-Chvátal cutting planes. P'; is a rational polyhedron provided that P is rational. The Chvátal-Gomory procedure is the iterative application of the elementary closure ...

Universität des Saarlandes2000

Living inside a hedgehog: Higher-dimensional solutions that localize gravity

We consider spherically symmetric higher-dimensional solutions of Einstein's equations with a bulk cosmological constant and n transverse dimensions. In contrast to the case of one or two extra dimensions we find no solutions that localize gravity when n ≥ ...

2000

Spectral response of plasmon resonant nanoparticles with a non-regular shape

Olivier Martin

We study the plasmon resonances of 10 - 100 (nm) two-dimensional metal particles with a non-regular shape. Movies illustrate the spectral response of such particles in the optical range. Contrary to particles with a simple shape (cylinder, ellipse) non-reg ...

Optical Society of America2000

From regular images to animated heads: a least squares approach

Pascal Fua

We show that we can effectively fit arbitrarily complex animation models to noisy image data. Our approach is based on least-squares adjustment using of a set of progressively finer control triangulations and takes advantage of three complementary sources ...

1998