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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
421

Density Functional Investigations of Pure and Ligated Clusters

Casalenuovo, Kristen 04 May 2009 (has links)
Atomic clusters are attractive candidates for building motifs for new nano-assembled materials with desirable properties. At this nano-regime of matter, the size, shape, and composition of clusters changes their electronic structure and hence their properties. Computational modeling must work hand in hand with experiment to provide robust descriptions of the geometries and energetics of atomic clusters and how they might behave in a nano-assembled material. To this end, we have investigated three distinct species as model systems: antimony oxides SbxOy (x = 1, 2; y = 0 - 3), metal ion-solvent complexes Mm(NH3)n (M = Bi, Pb; m = 1 - 2, n = 0 - 4), and quantum dots Z10H16 (Z = Si, Ge) and β-Sn12H24. Their geometries and electronic structures have been determined using gradient-corrected density functional theory. The relative stabilities for antimony oxides have been examined by the respective comparison of highest-occupied and lowest-unoccupied molecular orbital (HOMO-LUMO) gaps and atomization energies. The superior electronic stability of Sb2O3 is indicated by its closed shell structure, wide HOMO-LUMO gap calculated to be 3.11 eV, and high atomization energy of 4.21 eV. Spin-orbit corrections were necessary for accurate calculation of the metal-solvent energetics, closing the gap between experimental and theoretical values by 1.05 eV for the electron affinity of the Pb atom. Quantum dot modeling of the well-established Si and Ge as well as the less-investigated Sn illuminated the accuracy of the CEP basis sets and the B3LYP functional over other DFT computational routes for clusters containing elements beyond the third row. Throughout, the results correlate well with experiment and higher order ab initio methods where data is available. These comparisons validate the accuracy of the computational routes used. This document was prepared in the Linux Ubuntu Open Office Suite 2.4.1.
422

Optical Characterization of Electrochemically Self-Assembled Compound Semiconductor Nanowires

Ramanathan, Sivakumar 01 January 2006 (has links)
Semiconductor nanowires have attracted considerable attention as possible source for lasers and optical storage media. We report the fabrication and optical characterization of ZnO and CdS nanowires. The former are produced by electrochemical deposition of Zn inside nanoporous alumina films containing regimented arrays of 10nm, 25nm and 50 nm diameter pores, followed by room temperature chemical oxidization. Fluorescence spectroscopy shows different characteristics associated with different sample diameter. The 50 nm ZnO nanowires show an exciton recombination peak and an additional peak related to the deep trap levels. 25 nm ZnO nanowires show a only the exciton recombination peak, which is red shifted, possibly due to quantum confined Stark effect associated with built in charges in the alumina. This feature can be exploited to produce light emitting devices whose frequency can be modulated with an external electric field. Such devices could be novel ultra-violet frequency modulators for optical communication and solar blind materials. In addition, we have investigated fluorescence spectra of 10-, 25- and 50-nm diameter CdS nanowires (relative dielectric constant = 5.4) self assembled in a porous alumina matrix (relative dielectric constant = 8-10). The spectra reveal peaks associated with free electron-hole recombination. The 10-nm wire spectra show an additional lower energy peak due to exciton recombination. In spite of dielectric de-confinement caused by the insulator having a higher dielectric constant than the semiconductor, the exciton binding energy increases almost 8-fold from its bulk value in the 10 nm wires. This increase is most likely due to quantum confinement accruing from the fact that the exciton Bohr radius (~5 nm) is comparable to or larger than the wire radius, especially if side depletion is taken into account. Such an increase in the binding energy could be exploited to make efficient room temperature luminescent devices in the visible range.
423

GRAPHENE-BASED SEMICONDUCTOR AND METALLIC NANOSTRUCTURED MATERIALS

Zedan, Abdallah 12 April 2013 (has links)
Exciting periods of scientific research are often associated with discoveries of novel materials. Such period was brought about by the successful preparation of graphene which is a 2D allotrope of carbon with remarkable electronic, optical and mechanical properties. Functional graphene-based nanocomposites have great promise for applications in various fields such as energy conversion, opteoelectronics, solar cells, sensing, catalysis and biomedicine. Herein, microwave and laser-assisted synthetic approaches were developed for decorating graphene with various semiconductor, metallic or magnetic nanostructures of controlled size and shape. We developed a scalable microwave irradiation method for the synthesis of graphene decorated with CdSe nanocrystals of controlled size, shape and crystalline structure. The efficient quenching of photoluminescence from the CdSe nanocrystals by graphene has been explored. The results provide a new approach for exploring the size-tunable optical properties of CdSe nanocrystals supported on graphene which could have important implications for energy conversion applications. We also extended this approach to the synthesis of Au-ceria-graphene nanocomposites. The synthesis is facilely conducted at mild conditions using ethylenediamine as a solvent. Results reveal significant CO conversion percentages between 60-70% at ambient temperatures. Au nanostructures have received significant attention because of the feasibility to tune their optical properties by changing size or shape. The coupling of the photothermal effects of these Au nanostructures of controlled size and shape with GO nanosheets dispersed in water is demonstrated. Our results indicate that the enhanced photothermal energy conversion of the Au-GO suspensions could to lead to a remarkable increase in the heating efficiency of the laser-induced melting and size reduction of Au nanostructures. The Au-graphene nanocomposites are potential materials for photothermolysis, thermochemical and thermomechanical applications. We developed a facile method for decorating graphene with magnetite nanocrystals of various shapes (namely, spheres, cubes and prisms) by the microwave-assisted-reduction of iron acetylacetonate in benzyl ether. The shape control was achieved by tuning the mole ratio between the oleic acid and the oleyamine. The structural, morphological and physical properties of graphene-based nanocomposites described herein were studied using standard characterization tools such as TEM, SEM, UV-Vis and PL spectroscopy, powder X-ray diffraction, XPS and Raman spectroscopy.
424

Croissance et spectroscopie de boîtes quantiques diluées d'InAs/InP(001) pour des applications nanophotoniques à 1,55 µm

Dupuy, Emmanuel 22 December 2009 (has links)
Ce travail porte sur la croissance épitaxiale et la caractérisation optique de boîtes quantiques d’InAs/InP(001) en faible densité en vue de la réalisation de nouveaux composants nanophotoniques émettant à 1,55 µm. Les propriétés structurales et optiques des îlots ont été corrélés pour différents paramètres de croissance d’un système d’épitaxie par jet moléculaire à sources solides. Nos résultats soulignent l’influence des reconstructions de surface d’InAs sur la forme des îlots. Des boîtes, plutôt que des bâtonnets allongés généralement observés,peuvent être directement formées dans des conditions de croissance adéquates. Une transition de forme de bâtonnets vers des boîtes est également démontrée par des traitements postcroissance sous arsenic. Les faibles densités de boîtes sont obtenues pour des faibles épaisseurs d’InAs déposées. Leur émission est facilement contrôlée à 1,55 µm par une procédure d’encapsulation spécifique appelé « double cap ». Quelques propriétés des boîtes individuelles d’InAs/InP sont ensuite évaluées. Les études de micro-photoluminescence révèlent des pics d’émission très fins et distincts autour de 1,55 µm confirmant les propriétés« quasi-atomiques » de ces boîtes uniques. Enfin, nous proposons pour la première fois une méthode à haute résolution spatiale qui permet d’étudier le transport de charges autour d’une boîte unique grâce à une technique de cathodoluminescence à basse tension d’accélération.Une mesure directe de la longueur de diffusion des porteurs avant capture dans une boîte a été obtenue. Ces résultats ouvrent de nouvelles perspectives quant à l’intégration de ces boîtes uniques dans des microcavités optiques pour la réalisation de sources de lumières quantiques à 1,55 µm. / This thesis focus on the epitaxial growth and optical characterization of diluted InAs/InP(001) quantum dots for the realisation of new nanophotonic devices emitting at 1.55μm. The structural and optical properties of the quantum islands are correlated to different growth parameters of a solid source molecular beam epitaxy system. Our results highlight the influence of InAs surface reconstructions on the island shape. Dots rather than elongated dashes usually observed can be directly formed by adequate growth conditions. Dash to dot shape transition is also demonstrated by post-growth treatments. Low dot densities are obtained for small InAs deposited thickness. Their emission wavelength is easily tuned to1.55 µm using the “double cap” procedure for the growth of the InP capping layer. Optical properties of such single InAs/InP quantum dots are then evaluated. Microphotoluminescence studies reveal sharp and well separated emission lines near 1.55 µm from single dots confirming their atom-like properties. Last, we propose for the first time a highspatial resolution method to study the carrier transport in the vicinity of a single quantum dotusing a low-voltage cathodoluminescence technique. A direct measurement of the carrier diffusion length before capture into one dot has been obtained. These results open the way to the integration of these single dots into optical micro-cavities for the realisation of quantumlight sources at 1.55 µm.
425

Luminescent Quantum dots for Cellular Analysis

Shi, Lifang 15 December 2007 (has links)
Luminescent quantum dots have attracted great interest in recent years among biological researchers since they provide solutions to problems associated with use of organic fluorophores in cellular studies. Quantum dots show high photostability, high emission quantum yield, narrow and symmetric emission peaks and size-dependent wavelength tunability. The objective of my PhD studies was to develop CdSe/ZnS quantum dot-based probes and utilize them in cellular assays. The first phase of the work was to develop luminescent quantum dot fluorescence resonance energy transfer (FRET) based probes for protease activity. The probes were based on FRET interactions between quantum dots that serve as donors and rhodamine molecular acceptors that were immobilized to the surface of the quantum dots through peptide linkers, which contained selective enzymatic cleavage sites. Upon enzymatic cleavage of the peptide linkers, the rhodamine molecules no longer provided an efficient energy transfer channel to the quantum dots, which brightened the previously quenched quantum dots. The probes were applied to detect enzyme activity, screen enzyme inhibitors, and discriminate between normal and cancerous cells primarily because of the difference in the proteolytic activity in extracellular matrices. The second phase of my work was to take advantage of FRET and quantum dots to develop pH sensor. First quantum dots were modified with metallothionein (MT) to be water-soluble and biocompatible. The MT-coated quantum dots were labeled with Rhodamine through the formation of amide bonds with å-amine group of lysine in MT peptide to form the probes. FRET efficiency between quantum dots (donor) and rhodamine (acceptor) was pH dependent. The final phase of my studies focused on the first preparation of reversible quantum dot-based cellular probes for labile iron. The MT coated quantum dots was modified with EDTA to form probes. When captured by the EDTA molecules, iron ions quenched the emission of quantum dots. Removal of iron from the quantum dot surface by free EDTA or other iron chelators with higher binding affinity resulted in a rise in the luminescence of quantum dots. The analytical properties of the probes including sensitivity, selectivity, and reversibility were characterized. Intracellular assays in iron-enriched astrocytes will be carried out.
426

Fabrication and modeling of SiGe Nanostructures Driven by Hetero-epitaxial Elasticity / Fabrication et modélisation de nanostructures SIGe guidées par l' élasticité hétéro-épitaxiale

Liu, Kailang 16 December 2016 (has links)
Nous étudions ici l’heteroepitaxie du silicium-germanium (SiGe), un système qui est couramment considéré comme le stéréotype de l’´épitaxie des semi-conducteurs. Bien que ce système ait déjà attiré une attention considérable en raison de ses applications pour l’ingénierie des bandes dans l’industrie microélectronique, le défi majeur du développement de nouveaux dispositifs à base de SiGe reste la croissance épitaxiale contrôlable des nanostructures auto-assemblées. Il est bien connu que SiGe suit un mode de croissance de Stranski-Krastanov, qui passe par la croissance de couches bidimensionnelles suivie par la croissance d’ılots tridimensionnels. Sous cette dénomination générique ”Stranski-Krastanov”, plusieurs comportements différents peuvent être identifiés. Une compréhension globale de tous ces comportements est encore partiellement manquante en raison de la complexité et de l’interaction de la cinétique et des forces motrices dynamiques, empêchant le d´développement de nouveaux dispositifs. Dans ce travail, nous nous concentrons sur l’auto- assemblage des nanostructures SiGe à la suite de la quête de l’émission de lumière pour les dispositifs photoniques, optoélectroniques et nanoélectroniques à base de Si. Par Même si l’innovation dans les dispositifs à base de Si a été stimulée récemment par le d´développement de silicium complétement épuisé sur les transistors isolants, une véritable percée serait la démonstration de l´émission de lumière et / ou l’absorption par les éléments du groupe IV, car il permet une intégration pratique dans les semi-conducteurs actuels. Dans ce travail, nous montrons d’abord les différents régimes de croissance des films contraints, c’est-à-dire l’instabilité par rapport aux régimes de nucléation. Nous d´développons un modèle qui résout la course de ces deux voies de croissance et d´dévoile les mécanismes des différents modes d’évolution morphologique entrainés par l’élasticité. Dans la seconde partie, nous examinons en détail l’auto-organisation naturelle des îles cohérentes. L’effet élastique direct induit la répulsion entre les îles cohérentes. Cependant, l’énergie de surface dépendant de la déformation qui a été négligée précédemment dans l’analyse de l’interaction île-île est révélée pour provoquer une attraction entre les iles. Il peut compenser la répulsion élastique directe au cours de l´état initial de la nucléation et conduire au regroupement d’îlots cohérents. Dans une troisième partie, nous étudions l’influence des échelons du substrat vicinal sur la formation et l’auto-organisation des îles. Nous démontrons que l’anisotropie de relaxation de la contrainte produite par les bords des gradins est à l’origine de l’allongement de l’instabilité perpendiculaire aux marches. Un accord quantitatif entre l’allongement de l’instabilité et l’anisotropie de relaxation de la souche est trouvé, ce qui approfondit les compréhensions de la croissance hétéroépitaxiale sur le substrat vicinal. Dans la quatrième partie, nous développons un nouveau procédé basé sur la condensation Ge lors de l’oxydation thermique du SiGe dilué. On étudie la cinétique du procédé de condensation SiGe et on fabrique la couche épandeuse de SiGe totalement contrainte par ce procédé de condensation particulier. / We investigate here the heteroepitaxy of silicon-germanium (SiGe), a system which is commonly regarded as the stereotype of semiconductor epitaxy. While this system has already attracted a tremendous amount of attention due to its applications for band-gap engineering in microelectronic industry, the major challenge facing the development of new SiGe-based devices remains the con- trollable epitaxial growth of self-assembled nanostructures. It is well-known that SiGe follows a Stranski-Krastanov growth mode, which proceeds via the growth of bi-dimensionnal layers followed by the growth of three-dimensional islands. Under this generic “Stranski-Krastanov” designation, several different behaviors can be identified. An overall understanding of all these behavior is still partially missing due to the complexity and the interplay of kinetics and energetic driving forces, preventing the development of new devices.In this work we focus on the self-assembly of SiGe nanostructures following the quest of light emission for integrated Si-based photonic, optoelectronic and nanoelectronic devices.Even if the innovation in Si-based devices has been boosted recently by the development of ultra-thin body fully depleted silicon on insulator transistors, a real breakthrough would be the demonstration of light emission and/or absorption by group IV elements since it allows the conve- nient integration into the nowadays semiconductors.In this work we first demonstrate the different growth regimes of strained films, i.e. instability versus nucleation regimes. We develop a model which resolves the race of these two growth pathways and unveil the mechanisms of different modes of morphological evolution driven by elasticity.In the second part, we examine in details the natural self-organisation of coherent islands. The direct elastic effect induces repulsion between coherent islands. However, the strain-dependent surface energy which has been overlooked previously in analysis of the island-island interaction is revealed to cause an attraction between islands. It may compensate the direct elastic repulsion during the initial state of nucleation and lead to the clustering of coherent islands.In a third part we study the influence of miscut steps of vicinal substrate on the formation and self-organisation of islands. We demonstrate that the strain relaxation anisotropy produced by the step edges, is at the origin of the instability elongation perpendicular to steps. Quantitative agreement between the instability elongation and the anisotropy of strain relaxation is found, which deepens the understandings of hetero-epitaxial growth on vicinal substrate.In the fourth part we develop a new process based on Ge condensation during thermal oxidation of dilute SiGe. The kinetics of SiGe condensation process is investigated and the fully strained SiGe epilayer is fabricated via this particular condensation process. This process can be applied in fabrication of SiGe core-shell nanostructures, for which the direct deposition and growth process is found to be cumbersome in terms of the control of morphology and composition.As a whole, we studied the nanostructures of SiGe driven by its hetero-epitaxial elasticity. We proposed a model to compare two pathways of morphological evolution of SK growth and unearthed the mechanisms of the race and transition. We studied kinetics of island nucleation under the impact of elastic filed produced by an existing island. The peculiar role of strain-dependent surface energy is highlighted. Then the elasticity anisotropy induced by miscut steps on vicinal substrate is studied theoretically and experimentally. This anisotropy effectively induces the elongation of islands in one direction to form nanowires in good alignment. Then the kinetics of condensation of SiGe is studied, which is found to be an effective method in fabricating strained SiGe nanostructures.
427

[en] TRANSPORT PROPERTIES OF NANOSCOPIC SYSTEMS: ATOMS AND MOLECULES / [pt] PROPRIEDADES DE TRANSPORTE DE SISTEMAS NANOSCÓPICOS: ÁTOMOS E MOLÉCULAS

EDSON VERNEK 16 May 2007 (has links)
[pt] Neste trabalho estudamos o transporte eletrônico em nano- estruturas de átomos e moléculas. Utilizando o método das funções de Green, abordamos o problema das interações elétron-elétron e elétron-fônon e seus efeitos na condutância do sistema. Apresentamos um estudo detalhado do regime onde essas duas interações são simultaneamente importantes e mostramos que elas produzem novos efeitos nas propriedades do sistema. Mostramos que no regime de bloqueamento de Coulomb, o desdobramento de Rabi devido á interação elétron-fônon produz um novo efeito na condutância, que denominamos de tunelamento Rabi ressonante assistido por fônons. No regime de Kondo esse desdobramento é responsável por um novo fenômeno, o efeito Kondo de carga não inteira. / [en] In this work we study the electronic transport in atomic and molecular structures. By using the Green´s function method, we address the problem of the electron-electron and electron-phonon interactions and their effects on the conductance of the system. We present a detailed study of the regime where these two interactions are simultaneously important and show that they produce new effects on the properties of the system. In the Coulomb blockadge regime, the Rabi splitting due to the electron- phonon interaction produces a new effect in the conductance of nanosystem, which we called Rabi-assisted ressonant tunneling. In the Kondo regime, this splitting is responsible for a new phenomena, the non integer-charge Kondo effect.
428

[en] GROWTH OF QUANTUM DOT TO THE FAMILIES INAS/INP, INAS/INGAAS E INAS/INGAALAS FOR FOTODETECTORS OF INFRARED RADIATION / [pt] CRESCIMENTO DE PONTOS QUÂNTICOS DAS FAMÍLIAS INAS/INP, INAS/INGAAS E INAS/INGAALAS PARA FOTODETECTORES DE RADIAÇÃO INFRAVERMELHA

ARTUR JORGE DA SILVA LOPES 03 October 2008 (has links)
[pt] Pontos quânticos (PQs) auto-organizáveis de InAs sobre InP, InGaAs, InGaAlAs utilizando-se substratos de InP foram crescidos pela deposição química de metal-orgânicos (MOCVD) e foram investigadas para fotodetectores. Para PQs de InAs crescidos sobre diferentes substratos de InP, têm-se que a presença de discordâncias é responsável pelo aumento na densidade planar dos PQs. O espectro de fotoluminescência (FL) das estruturas de InP/InxGa1-xAs/InAs/InP, com diferentes composições da camada ternária. Medidas com microscopia de força atômica (AFM) mostraram que os PQs mais altos são obtidos quando os mesmos são crescidos sobre uma camada de InxGa1-xAs com um descasamento de 1000ppm, e a altura decresce com o descasamento a partir deste valor. O espectro de FL dos PQs mostrou uma banda assimétrica, a qual envolve transições entre os níveis de energia dos PQs e pode ser decomposta em dois picos. Pico de energia mais alta desta banda foi observado para a amostra com PQs crescidos sobre uma camada de InxGa1-xAs casada e o pico foi deslocado para energias mais baixas para amostras tensionadas. Estruturas diferentes de PQ de InAs crescidas sobre uma camada de InGaAlAs casada com InP foram investigadas. Picos de fotocorrente extremamente estreitos foram observados, demonstrando um excelente potencial para sintonização estreita de comprimentos de onda. Foram desenvolvidas estruturas para detectar radiação superior à 10μm. Medidas de absorção mostrando uma dependência com a polarização mostraram eu as estruturas tem um confinamento total e são apropriadas para detecção sintonizável de radiação por incidência normal. / [en] Self-assembled InAs quantum dots (QD) over an InP, InGaAs, InGaAlAs on InP substrates were grown by metal-organic chemical vapor deposition (MOCVD) and were investigated for quantum dot infrared photodetectors. For InAs QD over an InP buffer on different InP substrates. The results indicate that the presence of dislocations were responsible for the increase in the QD density. Photoluminescence (PL) spectra of InP/InxGa1-xAs/InAs/InP dot-in-a-well structures, with different compositions of the ternary layer. Measurements with atomic force microscopy showed that the largest QD height is obtained when the InAs QDs are grown on the InxGa1-xAs layer with a mismatch of 1000ppm, and the height decreases as the mismatch departs from this value. PL spectra of the QDs showed an asymmetric band, which involves transitions between dot energy levels and can be deconvoluted into two peaks. The highest energy PL peak of this band was observed for the sample with the QDs grown on top of the lattice-matched InxGa1-xAs and it shifted to lower energies for strained samples as the degree of mismatch increased. Different InAs quantum dot structures grown on InGaAlAs lattice matched to InP. Extremely narrow photocurrent peaks were observed, demonstrating great potential for fine wavelenght selection. Structures which can detect radiation beyond 10ìm were developed. Polarization dependence measurements showed that the structures have a zero- dimensional character and are suitable for detection of normal incidence light.
429

Crescimento e caracterização de pontos quânticos naturais de InAs e In0.5Ga0.5As sobre diferentes orientações cristalográficas do substrato de GaAs. / Characterization of InAs and In0.5Ga0.5As self-assembled quantum dots grown on different crystallographic orientations of GaAs substrate.

Borrero, Pedro Pablo Gonzalez 31 March 1998 (has links)
Pontos quânticos naturais ou auto-organizados de InAs e In0.5Ga0.5As foram produzidos sobre substratos de GaAs com diferentes orientações cristalográficas, utilizando-se a técnica de Epitaxia por Feixes Moleculares. Tais pontos foram caracterizados in situ através da Difração de Elétrons de Alta Energia por Reflexão (RHEED). As características do padrão do RHEED permitiram a determinação da espessura crítica para a qual ocorre a transição do modo de crescimento em duas dimensões para o de três dimensões, assim como também os planos perto dos quais, as faces das ilhas se encontram. A verificação dos resultados do RHEED foi feita utilizando Microscopia por Força Atômica. Esta técnica permitiu também determinar tanto a forma, densidade, altura e base das ilhas, como a morfologia da superfície onde os pontos não foram formados. Estudos ópticos das ilhas foram realizados, utilizando a técnica de Fotoluminescência (FL). Os resultados permitiram observar uma grande dependência dos espectros de FL com a orientação do substrato. Tal dependência é constatada na intensidade, forma e posição energética do pico de FL. A existência de um confinamento lateral adicional nestes pontos foi observada na dependência da intensidade do pico de FL com a temperatura. Medidas de polarização mostraram uma grande anisotropia estrutural para os pontos quânticos no plano, em concordância com os resultados do RHEED. / Self-assembled or self-organized quantum dots (QDs) of InAs and In0.5Ga0.5As were produced on different crystallographic oriented GaAs substrates using Molecular Beam Epitaxy. During the growth process the dots were characterized in situ by means of Reflection High-Energy Electron Diffraction (RHEED). The features of RHEED pattern allowed the determination of the critical thickness, for which the transition 2D-3D occur, as well as the crystallographic planes of island facets. Confirmation of the RHEED observations was done using Atomic Force Microscopy (AFM). This technique allowed also determining the form and dimensions of each QD as well as the density of islands. Optical study of quantum dots was carried out by Photoluminescence (PL). Such characterization allowed us to observe a high dependence of PL peak intensity, peak form and peak position, and an additional lateral confiment at quantum dots was verified in the temperature dependence of PL peak intensity. Polarization measurements presented a strong anisotropy h-plane for self-assembled quantum dots, in agreement with RHEED observations.
430

"O tratamento supervisionado no domicílio para o controle da tuberculose no município de Ribeirão Preto, SP-Brasil: avaliação do desempenho" / Domiciliary Supervised Treatment for Tuberculosis Control in Ribeirão Preto, SP. – Brazil: performance evaluation.

Gonzales, Roxana Isabel Cardozo 14 April 2005 (has links)
Trata-se de um estudo exploratório cujo objetivo foi avaliar o “desempenho" dos serviços de saúde que executam o DOTS/TS Domiciliar no Programa de Controle da Tuberculose (PCT) em Unidades de Saúde do Município de Ribeirão Preto. Utilizou-se como referencial metodológico os enfoques básicos para avaliação da qualidade da atenção médica Estrutura-Processo-Resultado proposto por Donabedian (1980) e modificado por Tanaka e Melo (2001) e Starfield (2002). Elaborou-se os seguintes indicadores: Cobertura, Aproveitamento dos recursos, Agilidade do desempenho, Monitoração da administração da medicação e Tempo gasto por visita domiciliar. Os dados foram coletados em 4 PCT por meio da Técnica de Observação Sistemática das visitas domiciliares, realizadas pelo profissional de saúde responsável pela supervisão do tratamento do paciente durante o mês de julho de 2003. Foram acompanhados todos os pacientes que no período em estudo receberam DOTS/TS no domicílio e aqueles que foram incluídos na supervisão durante a coleta de dados. A avaliação do desempenho foi realizada na relação de indicadores e complementada em função da análise por indicador a partir da média e do intervalo de confiança. Os indicadores estudados mostraram que o planejamento de recursos, a organização do trabalho pela equipe de saúde, a definição de funções e a sistematização das ações no processo de tratamento do doente de tuberculose podem influenciar no melhor desempenho do serviço de saúde em termos de cobertura, aproveitamento dos recursos, agilidade, monitoração da administração da medicação e tempo gasto por visita domiciliar. Assim, perante as restrições de recursos humanos e materiais no setor saúde, existe a necessidade de reconsiderar outras formas de supervisão e/ou integração das atividades de tratamento e controle da doença a outras estratégias de intervenção que resultem no uso racional dos recursos, melhor cuidado de saúde e sucesso do tratamento. / This exploratory study aimed to evaluate the “performance" of health services that execute Domiciliary DOTS/TS in the Tuberculosis Control Program (TCP) at Health Units in Ribeirão Preto. The methodological reference framework was based on the basic focuses for medical care quality evaluation Structure-Process-Outcome proposed by Donabedian (1988) and modified by Tanaka and Melo (2001) and Starfield (2002). The following indicators were elaborated: Coverage, Use of recourses, Performance agility, Medication administration monitoring and Time spent per home visit. Data were collected in 4 TCP by means of the Systematic Observation Technique of home visits, realized by the health professional who was responsible for supervising the patient’s treatment in July 2003. All patients were accompanied who were receiving domiciliary DOTS/TS during the study period, as well as those included in the supervision during data collection. The performance evaluation was accomplished in the indicator list and complemented in function of the analysis per indicator, based on mean values and confidence intervals. The studied indicators demonstrated that the planning of resources, the health team’s organization of its work, the definition of function and the systemization of actions in tuberculosis patients’ treatment can influence in the sense of achieving a better performance by the health service in terms of coverage, use of resources, agility, medication administration monitoring and time spent per home visit. Thus, in view of health sector restrictions in terms of human and material resources, there is a need to reconsider other forms of supervising and/or integrating treatment and control activities with other intervention strategies that can result in the rational use of resources, a better healthcare and a successful treatment.

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