published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

published_or_final_version / Electrical Engineering / Master / Master of Science in Engineering

Nous considérons plusieurs problèmes autour des matrices à signes alternants (MSA). Dans un premier chapitre nous donnons une formule de comptage des MSAs selon le nombre k de -1 qu'elles contiennent et leur taille n. Cette formule permet d'obtenir une évaluation asymptotique pour un k donné lorsque n tend vers l'infini et une expression simple pour les valeurs de k inférieures ou égales à 7.Une deuxième partie est consacrée à une famille de MSAs dont les triangles Gogs (ou triangles monotones) associés sont en bijection avec une famille de triangles Magogs (ou des partition planes auto complémentaires symétriques). Nous présentons une méthode de minoration du nombre d'éléments de taille n dans cette famille d'objets.Enfin, nous évaluons la probabilité d'apparition de motifs (sous-diagrammes) dans des diagrammes de cordes tirés selon la distribution limite introduite par la conjecture de Razumov et Stroganov. / Abstract

xiii, 370 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Electrical Engineering, 1980

The goal of this thesis is to identify and to explore novel ACTFEL phosphor materials. Several important materials properties relevant to ACTFEL phosphor development are identified. All of these properties cannot be obtained simultaneously. Therefore, several key phosphor materials properties are identified as critical to the development of an ACTFEL phosphor. Then, using basic chemical trends, several classes of potential ACTFEL phosphors are identified. These materials systems include halides, nitrides, oxynitrides, oxides, sulfides, and inhibited concentration quenching systems. Representative materials from some of these proposed novel ACTFEL phosphor materials system are developed and evaluated as electroluminescence phosphors. Most of the ACTFEL devices made using these materials do not show any significant charge transfer. Detailed analysis indicates that the most probable cause of the lack of charge injection is that the phosphor threshold field is too large. This excessively large threshold field may be associated with the energy depth of the interface states, the low density of the interface states, or the large effective mass of the phosphor material explored. Several possible alternative solutions are presented to reduce the threshold field of the phosphor. These includes the use of thick-film insulator, the use of a charge injection layer, the use of a ceramic substrate coupled with a high temperature interface reaction, and the use of bulk doping of the phosphor. / Graduation date: 1997

The use of Robin boundary conditions as interfacial transmission conditions in nonoverlapping domain decomposition iterative procedures was introduced by P.~L.~Lions and later discussed by a number of authors. In all of these discussions, the weighting of the flux and the trace of the solution were independent of the iterative step number. Recently, Douglas and Huang have considered an extension in which the weighting has depended on the iterative index and proved that an acceleration in the convergence rate similar to that occurring for alternating-direction iteration using a cycle of pseudo-time steps results. Combined methods have received a lot of attention on the study of the boundary value problems of elliptic equation with singularities domain. The objects of this paper are to extend this accelerated procedure to a singularity problem on a sectorial domain. We show that the convergence rate similar to that occurring for alternating-direction iteration results. Also, a combined method and the methodology of weighting parameter can be used to solve a singularity problem.

Classical alternating direction (AD) methods for parabolic equations, based on some standard implicit time stepping procedure such as Crank-Nicolson, can have errors associated with the AD perturbations that are much larger than the errors associated with the underlying time stepping procedure . We plan to show that minor modifications in the AD procedures can virtually eliminate the perturbation errors at an minor additional computational cost. A mixed finite element method is applied in the spactial variables. Similar to the finite difference and finite element methods in spactial variables, we plan to have the same accuracy in time. A convergence analysis can also be shown .

published_or_final_version / Electrical and Electronic Engineering / Master / Master of Philosophy

published_or_final_version / Electrical Engineering / Master / Master of Philosophy

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