95 research outputs found
Two-parameter Sturm-Liouville problems
This paper deals with the computation of the eigenvalues of two-parameter
Sturm- Liouville (SL) problems using the Regularized Sampling Method, a method
which has been effective in computing the eigenvalues of broad classes of SL
problems (Singular, Non-Self-Adjoint, Non-Local, Impulsive,...). We have shown,
in this work that it can tackle two-parameter SL problems with equal ease. An
example was provided to illustrate the effectiveness of the method.Comment: 9 page
Computation of the Eigenpairs of Two-Parameter Sturm-Liouville Problems Using the Regularized Sampling Method
This paper deals with the computation of the eigenvalues of two-parameter Sturm-Liouville (SL) problems using the Regularized Sampling Method, a method which has been effective in computing the eigenvalues of broad classes of SL problems (singular, non-self-adjoint, nonlocal, impulsive, etc.). We have shown, in this work that it can tackle two-parameter SL problems with equal ease. An example was provided to illustrate the effectiveness of the method
Dynamic formation of spherical voids crossing linear defects
A predictive model for the evolution of porous Ge layer upon thermal
treatment is reported. We represent an idealized etched dislocation core as an
axially symmetric elongated hole and computed its dynamics during annealing.
Numerical simulations of the shape change of a completely spherical void via
surface diffusion have been performed. Simulations and experiments show
individual large spherical voids, aligned along the dislocation core. The
creation of voids could facilitate interactions between dislocations, enabling
the dislocation network to change its connectivity in a way that facilitates
the subsequent annihilation of dislocation segments. This confirms that
thermally activated processes such as state diffusion of porous materials
provide mechanisms whereby the defects are removed or arranged in
configurations of lower energy. This model is intended to be indicative, and
more detailed experimental characterization of process parameters such as
annealing temperature and time, and could estimate the annealing time for given
temperatures, or vice versa, with the right parameters.Comment: 7 pages, 3 figure
Chemical composition of nanoporous layer formed by electrochemical etching of p-type GaAs
Abstract : We have performed a detailed characterization study of electrochemically etched p-type GaAs in a hydrofluoric acid-based electrolyte. The samples were investigated and characterized through cathodoluminescence (CL), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). It was found that after electrochemical etching, the porous layer showed a major decrease in the CL intensity and a change in chemical composition and in the crystalline phase. Contrary to previous reports on p-GaAs porosification, which stated that the formed layer is composed of porous GaAs, we report evidence that the porous layer is in fact mainly constituted of porous As2O3. Finally, a qualitative model is proposed to explain the porous As2O3 layer formation on p-GaAs substrate
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