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Full-Text Articles in Engineering
Excitation And De-Excitation Mechanisms Of Er-Doped Gaas And Algaas, David W. Elsaesser
Excitation And De-Excitation Mechanisms Of Er-Doped Gaas And Algaas, David W. Elsaesser
Theses and Dissertations
Electrical and optical characterization have been performed on GaAs and AlxGa1-xAs samples doped with Er either by ion implantation or during Molecular Beam Epitaxial (MBE) growth. Deep Level Transient Spectroscopy (DLTS) and Temperature-Dependent Hall Effect (TDH) measurements indicated the presence of two hole traps in Er-doped GaAs, at 35 and 360 meV above the valence band maximum. The former (shallower) center was thought to be due to Er substituting for a Ga atom (ErGa) and giving rise to an isoelectronic impurity potential. The second center was attributed to an Er atom occupying an interstitial …
Identification Of The Initial Transient In Discrete-Event Simulation Output Using The Kalman Filter, Mark A. Gallagher
Identification Of The Initial Transient In Discrete-Event Simulation Output Using The Kalman Filter, Mark A. Gallagher
Theses and Dissertations
Data truncation is a commonly accepted method of dealing with initialization bias in discrete-event simulation. Algorithms for determining the appropriate initial-data truncation point for univariate and multivariate output are proposed. The techniques entail averaging across replications and estimating a steady-state output model in a state-space framework. Using the estimated model, Multiple Model Adaptive Estimation (MMAE), which uses Kalman filters with different parameter vectors, is applied. Based on the filters' residuals, the conditional probabilities of each filter's specific parameter vector being correct are determined. The MMAE parameter estimates are the probabilistic- weighted average of the filters' assumed parameter vectors. The estimated …
A General Three Dimensional All Quadrilateral Surface Mesh Generation Algorithm, Roger Cass
A General Three Dimensional All Quadrilateral Surface Mesh Generation Algorithm, Roger Cass
Theses and Dissertations
Among the available all-quadrilateral mesh generation algorithms progressive-front offers the best quality and robustness. The paving algorithm is a progressive-front technique that generates a two dimensional mesh of all quadrilaterals on planar surfaces. The technique is particularly suited to meshing irregular boundaries with interior holes. This thesis presents an extension of the paving algorithm to generalized three dimensional surfaces. The major problems in three-dimensional surface mesh generation are projection of nodes, calculation of interior angles, and connection of mesh fronts. The solutions to these problems are presented. This work is part of the ongoing CUBIT project at Sandia Labs. The …