5,992 research outputs found
Internal and External Resonances of Dielectric Disks
Circular microresonators (microdisks) are micron sized dielectric disks
embedded in a material of lower refractive index. They possess modes with
complex eigenvalues (resonances) which are solutions of analytically given
transcendental equations. The behavior of such eigenvalues in the small opening
limit, i.e. when the refractive index of the cavity goes to infinity, is
analysed. This analysis allows one to clearly distinguish between internal
(Feshbach) and external (shape) resonant modes for both TM and TE
polarizations. This is especially important for TE polarization for which
internal and external resonances can be found in the same region of the complex
wavenumber plane. It is also shown that for both polarizations, the internal as
well as external resonances can be classified by well defined azimuthal and
radial modal indices.Comment: 5 pages, 8 figures, pdflate
Effect of rhenium on the structure and properties of the weld metal of a molybdenum alloy
The structure and properties of welds made in molybdenum alloy VM-1 as a function of rhenium concentrations in the weld metal were studied. Rhenium was introduced into the weld using rhenium wire and tape or wires of Mo-47Re and Mo-52Re alloys. The properties of the weld metal were studied by means of metallographic techniques, electron microscopy, X-ray analysis, and autoradiography. The plasticity of the weld metal sharply was found to increase with increasing concentration of rhenium up to 50%. During welding, a decarburization process was observed which was more pronounced at higher concentrations of rhenium
Short time dynamics with initial correlations
The short-time dynamics of correlated systems is strongly influenced by
initial correlations giving rise to an additional collision integral in the
non-Markovian kinetic equation. Exact cancellation of the two integrals is
found if the initial state is thermal equilibrium which is an important
consistency criterion. Analytical results are given for the time evolution of
the correlation energy which are confirmed by comparisons with molecular
dynamics simulations (MD)
On the interrelation between monopoles, vortices, topological charge and chiral symmetry breaking: an analysis using overlap fermions for SU(2)
We study the properties of configurations from which P-vortices on one hand
or Abelian monopoles on the other hand have been removed. We find that the zero
modes and the band of non-zero modes close to zero disappear from the spectrum
of the overlap Dirac operator, confirming the absence of topological charge and
quark condensate. The different behavior of the modified ensembles under
smearing compared to the unmodified Monte Carlo ensemble corroborates these
findings. The gluonic topological susceptibility rapidly approaches zero in
accordance with Q_{index}=0. The remaining (ultraviolet) monopoles without
vortices and -- to a less extent -- the remaining vortices without monopoles
are unstable under smearing whereas smearing of the unmodified Monte Carlo
ensemble effects the monopoles and vortices only by smoothing, reducing the
density only slightly.Comment: 13 pages, 5 figures, strongly revised, results added, one figure
added, accepted for publication, title changed
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