144,551 research outputs found
Collective resonant modes of a meta-surface
A periodic layer of resonant scatterers is considered in the dipolar
approximation. An asymptotic expression for the field diffracted is given in
terms of an impedance operator. It is shown that surface Bloch modes appear as
a collective effect due to the resonances of the scatterers.Comment: 9 pages, 7 figures, extended paper from SPIE Optics+Photonics,
Nanostructured Thin Films VI;submitted to Journal of Nanophotonic
Robust equilibrated a posteriori error estimators for the Reissner-Mindlin system
We consider a conforming finite element approximation of the Reissner-Mindlin
system. We propose a new robust a posteriori error estimator based on H(div)
conforming finite elements and equilibrated fluxes. It is shown that this
estimator gives rise to an upper bound where the constant is one up to higher
order terms. Lower bounds can also be established with constants depending on
the shape regularity of the mesh. The reliability and efficiency of the
proposed estimator are confirmed by some numerical tests
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