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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.
151

Montage et caractérisation d’un système de spectroscopie Raman accordable en longueur d’onde utilisant des réseaux de Bragg comme filtre : application aux nanotubes de carbone

Meunier, François 04 1900 (has links)
La spectroscopie Raman est un outil non destructif fort utile lors de la caractérisation de matériau. Cette technique consiste essentiellement à faire l’analyse de la diffusion inélastique de lumière par un matériau. Les performances d’un système de spectroscopie Raman proviennent en majeure partie de deux filtres ; l’un pour purifier la raie incidente (habituellement un laser) et l’autre pour atténuer la raie élastique du faisceau de signal. En spectroscopie Raman résonante (SRR), l’énergie (la longueur d’onde) d’excitation est accordée de façon à être voisine d’une transition électronique permise dans le matériau à l’étude. La section efficace d’un processus Raman peut alors être augmentée d’un facteur allant jusqu’à 106. La technologie actuelle est limitée au niveau des filtres accordables en longueur d’onde. La SRR est donc une technique complexe et pour l’instant fastidieuse à mettre en œuvre. Ce mémoire présente la conception et la construction d’un système de spectroscopie Raman accordable en longueur d’onde basé sur des filtres à réseaux de Bragg en volume. Ce système vise une utilisation dans le proche infrarouge afin d’étudier les résonances de nanotubes de carbone. Les étapes menant à la mise en fonction du système sont décrites. Elles couvrent les aspects de conceptualisation, de fabrication, de caractérisation ainsi que de l’optimisation du système. Ce projet fut réalisé en étroite collaboration avec une petite entreprise d’ici, Photon etc. De cette coopération sont nés les filtres accordables permettant avec facilité de changer la longueur d’onde d’excitation. Ces filtres ont été combinés à un laser titane : saphir accordable de 700 à 1100 nm, à un microscope «maison» ainsi qu’à un système de détection utilisant une caméra CCD et un spectromètre à réseau. Sont d’abord présentés les aspects théoriques entourant la SRR. Par la suite, les nanotubes de carbone (NTC) sont décrits et utilisés pour montrer la pertinence d’une telle technique. Ensuite, le principe de fonctionnement des filtres est décrit pour être suivi de l’article où sont parus les principaux résultats de ce travail. On y trouvera entre autres la caractérisation optique des filtres. Les limites de basses fréquences du système sont démontrées en effectuant des mesures sur un échantillon de soufre dont la raie à 27 cm-1 est clairement résolue. La simplicité d’accordabilité est quant à elle démontrée par l’utilisation d’un échantillon de NTC en poudre. En variant la longueur d’onde (l’énergie d’excitation), différentes chiralités sont observées et par le fait même, différentes raies sont présentes dans les spectres. Finalement, des précisions sur l’alignement, l’optimisation et l’opération du système sont décrites. La faible acceptance angulaire est l’inconvénient majeur de l’utilisation de ce type de filtre. Elle se répercute en problème d’atténuation ce qui est critique plus particulièrement pour le filtre coupe-bande. Des améliorations possibles face à cette limitation sont étudiées. / Raman spectroscopy is a useful and non-destructive tool for material characterization. It uses inelastic light scattering interaction with matter to investigate materials. The major part of the performances in a Raman spectroscopy system comes from two light filter units: the first shapes the light source (usually a laser) and the other attenuates the elastic scattered light in the signal beam. In resonant Raman spectroscopy (RRS), the excitation energy (wavelength) is tuned to match an electronic transition of the sample. When in resonance, the Raman cross section is increased by a factor up to 106. Current RRS setups are limited by filtering devices technology. RRS is a complex technique which, for the moment, remains tedious to implement. This master thesis presents the construction of a tunable Raman spectroscopy system based on volume Bragg gratings light filters. The setup is designed to operate in the near infrared region so as to study carbon nanotubes resonances. Steps leading to the operation of the system are described. They cover conceptualization, fabrication, characterization and optimisation of the setup. Collaboration with a local small company, Photon etc, led to the building of two new light filters that allow to tune easily the excitation wavelength. These filters have been adapted to work with a tunable titanium-sapphire laser (tunable from 700 to 1100 nm) and assembled with a homemade microscope and a detection system combining a CCD camera with a grating spectrometer. This document is arranged as follow: First are presented the theoretical aspects surrounding RRS. Carbon nanotubes (CNT) are than described to illustrate the relevance of such technique applied to material science. Principles behind the use of the Bragg filters are described to be followed by a scientific paper in which the main results of this work are presented. These include the optical characterisation of the filters and measurements with the system. Low frequency limits of the system are demonstrated using a sulphur powder where the 27 cm-1 line is clearly resolved. The tunability of the setup is also demonstrated using a bulk carbon nanotube sample. By changing the excitation wavelength, different nanotube chiralities become resonant, leading to different signals in the Raman spectra. Finally, clarifications regarding the alignment, optimisation and operation of the system are described. Low angular acceptance has been found to be the main drawback of the system leading to attenuation problems especially critical for the notch filter. Possible improvements on this limitation are discussed.
152

Développement de la tomographie par rayons X en synchrotron pour l'industrie : application à l'analyse de défaillance en intégration 3D / Towards the industrial use of synchrotron x-ray nano-tomography for 3D integration failure analysis

Fraczkiewicz, Alexandra 12 December 2017 (has links)
Ce travail de thèse vise à développer de nouvelles techniques de caractérisation pour l'intégration 3D en micro-électronique. Plus précisément, ce travail porte sur l'imagerie 3D de tels objets et la mesure des contraintes par diffraction de Bragg, réalisées sur de récentes lignes de lumière de l'ESRF (European Synchrotron Radiation Facility).L'intégration 3D a pour but de répondre aux besoins de performances de la micro-électronique, en empilant les différents éléments constituant les puces au lieu de les placer les uns à côté des autres; ceci permet de limiter la place qu'ils occupent et la longueur des connections. Pour ce faire, de nouvelles connections entre puces ont du être développées, telles que les piliers de cuivre et les pads de cuivre, utilisés dans le cas du collage hybride. Afin de maîtriser leurs procédé de fabrication, il est important de pouvoir caractériser ces objets, à la fois par des moyens d'imagerie et de mesure de la déformation dans les puces. Ces mesures doivent permettre un large champ de vue (100 µm), ainsi qu'une haute résolution (50 nm). De plus, afin de satisfaire les besoins en temps de l'industrie micro-électronique, les techniques choisies doivent être aussi rapides et automatiques que possible.Pour satisfaire ces besoins, plusieurs techniques ont été étudiés durant ces travaux de thèse.Une technique d'imagerie 3D par Slice and View, inspirée de la technique classique du FIB/SEM et implémentée dans un PFIB (Plasma Focused Ion Beam), a été développée durant ces travaux de thèse. Elle permet aujourd'hui l'acquisition de larges volumes de manière automatique. De même, le procédé d'analyse des mesures de tomographies réalisées sur la ligne de lumière ID16A de l'ESRF a été adapté, afin de limiter au maximum l'intervention humain et le temps global d'analyse.Des mesures de déformations ont également été menées à l'ESRF, sur une ligne de nano-diffraction, ID01. Ces expériences ont été réalisées sur des empilements dédiés au collage, hybride ou direct. Il a été possible de mesurer en une seule expérience les déformations présentes dans deux couches de silicium, et de réaliser des mesures textit{in situ} dans le cuivre.Dans les travaux de thèse présentés ici, nous montrons les possibilités de techniques synchrotron (imagerie et mesure de déformations) pour la caractérisation d'objets issus de l'intégration 3D. Nous montrons que certaines adaptations des techniques existante peuvent permettre des analyses routinières à haute résolution pour le milieu de la micro-électronique. / This PhD thesis aims at developing new characterization techniques for 3D integration in microelectronics. More specifically, the focus is set on recent ESRF (European Synchrotron Radiation Facility) beamlines, both for 3D imaging by tomography and for strain measurements by Bragg diffraction.3D integration aims at reducing the global microelectronics devices footprint and connections length, by stacking the dies on top of one another instead of setting them one to another. This new geometry however requires new connections, such as copper pillars (CuP) and copper pads, used in hybrid bonding. The monitoring of their fabrication process requires their imaging in three dimensions, and the measure of the strain inside them. Those measurements must be conducted on large areas (100 µm2), with high resolution (500 nm for strain and 100 nm for imaging). Moreover, given the industrial context of this study, the characterization methods must be as routine and automatic as possible.To answer those needs, several techniques have been developed in this work.Two 3D imaging techniques have been made compatible with the requirements of 3D integration characterization. A Slice and View procedure has been implemented inside a single beam PFIB, leading to large volumes 3D automated imaging. The tomography workflow accessible on the ID6A beamline of the ESRF has been adapted, in order to limit the human intervention and beam times. This leads to possible statistical measurements on this beamline.Strain measurements have been conducted on the ID01 beamline of the ESRF, on silicon and copper stacks meant for direct and hybrid bonding. They allowed for simultenous local strain measurements in two independent layers of silicon, and textit{in situ} measurements in copper.In this work, we show the possibilities of synchrotron based techniques (here, tomography and Bragg diffraction) for the chacracterization of 3D integration devices. We show that, provided some adjustments, these techniques can be used routinely for the microelectronics field.
153

[en] APPLICATIONS OF FIBER BRAGG GRATING SENSORS IN THE MEASUREMENT OF PH AND OF STRAIN IN HARD THIN FILMS / [pt] APLICAÇÕES DE SENSORES A REDE DE BRAGG EM FIBRAS ÓPTICAS NA MEDIÇÃO DE PH E DEFORMAÇÃO DE FILMES FINOS DE ALTA DUREZA

SULLY MILENA MEJIA QUINTERO 07 November 2006 (has links)
[pt] Este trabalho versa sobre duas diferentes aplicações de sensores a redes de Bragg em fibra óptica. A primeira consiste no desenvolvimento de uma técnica de sensoriamento do pH empregando fibra óptica, que visa a monitoração contínua e permanente deste parâmetro em poços de petróleo depletados e de injeção. Nesta aplicação, as redes de Bragg são acopladas, através de um mecanismo transdutor, a sistemas poliméricos que respondem a alterações do pH apresentando uma variação expressiva de seu volume. O tempo de resposta e o fator de inchamento do sistema polimérico foram caracterizados para valores de pH 3, 4, 5, e 6, em soluções aquosas contendo sais dissolvidos em concentrações típicas das encontradas em águas de formação. As medições foram realizadas a temperaturas e pressões ambientes, assim como na presença de óleo, e após a pressurização do sistema polimérico até 5000 psi. Diferentes mecanismos transdutores foram projetados e construídos, e suas respostas, avaliadas em soluções aquosas com composição similar à das águas de formação. Foram estimadas a sensibilidade da técnica e as principais fontes de incerteza na medição do pH. Procurou-se também avaliar a funcionalidade dos mecanismos transdutores visando uma futura instalação em poço. Na segunda aplicação, é proposta uma técnica para a medição in situ da tensão residual induzida em filmes finos de alta dureza durante sua deposição em câmaras de sputtering assitido por rádio-frequência e campo magnético. A técnica é constituída por uma viga em aço engastada, tendo uma de suas faces instrumentada com um conjunto de redes de Bragg a fibra óptica, enquanto a face oposta é exposta ao fluxo de íons do material a ser depositado. O sistema sensor é instalado em uma câmara que opera sob alto vácuo, enquanto os aparelhos de leitura permanecem no exterior. A resposta do protótipo em função de variações do campo magnético e da temperatura no interior da câmara foi levantada. Em seguinda, foram realizadas medições da deformação da viga durante a deposição de filmes de sílica, de óxido de titânio-índio, e de carbeto de silício. A tensão residual dos filmes foi calculada e comparada com resultados de medições de curvatura do substrato realizadas empregando um perfilômetro. Tensões residuais de 6 MPa até 0,2 Gpa foram obtidas durante as diferentes deposições. / [en] This work treats of two different applications of optical fiber Bragg grating sensors. The first application consists of a pH sensing technique that employs optical fiber to permanent and continuously monitor the pH in depleted and injection oil wells. In this application, the Bragg gratings are coupled by a transduction mechanism to a polymeric system which responds to pH variations with a large volume change. The response time as well as the swelling factor of the polymeric system at pH 3, 4, 5, and 6 have been characterized in aqueous solutions with dissolved salts in concentrations typical of those found in formation waters. Experiments have been carried out at room temperature and pressures, in the presence of oil, and after pressurization up to 5000 psi. Several mechanisms of transduction have been designed, constructed, and tested in solutions similar to the formation waters. The sensitivity of the technique and the main sources of uncertainties related to the pH measurement have been investigated. Also, the functionality of the mechanisms has been evaluated aiming at a future installation in the petroleum wells. The second application investigated is a technique for in situ measurement of the residual stress induced in hard thin films during deposition by RF magnetron sputtering. The sensing technique consists of a cantilever steel beam. One of the surfaces of the beam is instrumented using optical fiber Bragg gratings; the opposite face is exposed to the ion flux that originates the thin film. The sensing system is installed in a vacuum chamber while the interrogating apparatus remains outside. The prototype has been characterized with respect to variations of the magnetic field and the temperature inside the chamber. Measurements of the beam strain have been carried out during deposition of silica, indium- titanium oxide, and silicon carbide thin films. The residual stresses have been calculated and the results compared with data obtained using perfilometry. Residual stress values varying from 6 MPa up to 200 MPa have been obtained during the different deposition processes.
154

[en] MONITORING CORROSION DEFECTS IN PLANAR STRUCTURES WITH FIBER BRAGG GRATING SENSORS / [pt] MONITORAÇÃO DE DEFEITOS POR CORROSÃO EM ESTRUTURAS PLANAS UTILIZANDO SENSORES A REDE DE BRAGG

DARWIN GRAMER FALCON SORIA 29 March 2012 (has links)
[pt] O foco do presente trabalho é a detecção e o monitoramento de defeitos tais como perda de espessura por corrosão ou dano produzido por impacto em painéis metálicos planos. O sistema proposto emprega sensores de deformação a fibra óptica baseados em redes de Bragg, que possuem alta capacidade de multiplexação. O campo de deformações produzido na superfície da placa por um mesmo carregamento, cuja amplitude pode variar, é continuamente comparado a um mapa de referência, obtido com a estrutura íntegra ou na presença um defeito previamente detectado. Variações nos gradientes de deformações são associadas ao surgimento ou crescimento de um ou mais defeitos. Neste estudo, a metodologia foi preliminarmente avaliada através da análise de campos de deformação produzidos por carregamentos de tração em corpos de alumínio contendo defeitos superficiais. Esses defeitos exemplificam danos causados por corrosão, e são monitorados através de sensores a fibra óptica baseados em redes de Bragg. Os sensores são posicionados ao longo de uma das superfícies da placa, medindo deformações em duas direções ortogonais, que neste estudo corresponderam às direções principais de deformação. A abordagem do problema fundamenta-se na análise de dados experimentais e modelagem numérica por elementos finitos. Os resultados numéricos para as deformações são comparados com os obtidos em experimentos em laboratório. A técnica é utilizada para avaliar qualitativamente os defeitos em estruturas submetidas a carregamento estático. A correlação entre resultados numéricos e experimentais mostraram-se satisfatórias, indicando que o método apresenta potencial para ser estendido para aplicações mais complexas. / [en] The present work is focused on detecting and monitoring damage such as loss of thickness due to corrosion or other planar defects in flat metallic panels. The proposed method employs fiber optic sensors that, due to their high multiplexing capability, are capable of mapping the strain fields in the panel surfaces produced by the same, controlled, loading, which are then continuously compared to a reference map obtained with the structure free of defects or with a previously detected damage. Changes in the strain gradient are attributed to the appearance or growth of structural damage. The proposed approach for structural health monitoring has been preliminarily evaluated in this dissertation by analyzing the strain fields produced on an aluminum plate under in plane tensile loads. Artificial, localized surface defects, simulating a loss of thickness due to corrosion where the investigated defects. A mesh of fiber Bragg grating sensors was installed on one of the panel surfaces measuring its principal strains. The strain fields obtained with the plate containing defects with different depths and sizes were compared to a reference measurement with the panel without defects. Experimental data was compared with numerical simulations based on the Finite Element method. The correlation between numerical and experimental results was satisfactory indicating that the method can be further developed in order to be applied in implementations of structural health monitoring systems.
155

Etude d'un spéctromètre intégré SWIFTS pour réaliser des capteurs optiques fibrés pour les sciences de l'observation / Integrated spectrometer SWIFTS for photosensitive fiber sensors applied to observation sciences

Mengin Fondragon, Mikhael de 18 November 2014 (has links)
SWIFTS (pour Stationary-Wave Integrated Fourier-Transform Spectrometer) est un concept de spectromètre s'appuyant sur l'optique intégrée pour proposer un système de mesure compact et de très haute résolution. Il combine une technique d'interférométrie développée par Gabriel Lippmann avec des technologies de microélectroniques actuelles. La technologie SWIFTS sera ici utilisée en tant qu'interrogateur de fibre de Bragg. En effet, combiner ce spectromètre avec des fibres de Bragg très sensibles, telle qu'une cavité Fabry-Perot à réseaux de Bragg (GFPC) d'une longueur de 20 mm, permettra de mesurer des variations de température et de déformation très précises. Les applications des fibres de Bragg sont nombreuses, particulièrement dans la surveillance de structure de génie civil ou dans la sureté nucléaire avec des précisions de l'ordre du microstrain. Cependant, les capteurs par fibres de Bragg n'ont jamais atteint la sensibilité nécessaire aux observations en science de la terre. Une précision de quelques dizaines de nanostrain serait pourtant d'un intérêt majeur dans l'étude des processus volcaniques et sismologiques. Je présente dans cette thèse la première utilisation d'un tel spectromètre de Fourier associé à des capteurs de Bragg pour mesurer des déformations dans différentes gammes allant du millistrain au nanostrain. Dans un premier temps, des déformations sur une petite structure en béton armé amenée jusqu'à l'état limite de fissuration permettront de qualifier différents capteurs à fibres de Bragg dans leur milieu d'usage. Dans un deuxième temps, des mesures de déformations liées au phénomène de la marrée terrestre sont proposées. Ces mesures, effectuées au Laboratoire Souterrain à Bas Bruit (LSBB) de Rustrel, donnent des précisions de l'ordre de 30 nanostrains sur une courte base et ouvrent la voie à d'autres mesures de phénomènes géophysiques pour cet instrument. / SWIFTS, or Stationary-Wave Integrated Fourier-Transform Spectrometer, is an extremely integrated very high resolution spectrometer. This spectroscopy technology represents a major advance in the field and will be used here as a Fiber Bragg Gratings interrogator. Combining such a spectrometer with very sensitive Bragg sensors, like grating Fabry-Perot cavity (GFPC) as long as 20 mm, will allow to measure high precision temperature or strain variation. Applications of Bragg sensors are numerous, especially in structure monitoring and nuclear power plants safety. Despite promising capabilities, Bragg sensors never reached the desired sensibility for earth-science observation purposes. Present applications are restricted to civil-engineering strain-gauge sensors with microstrain sensitivity. However, the ability to detect and record signals of the order of a few tens of nanostrain is of great interest to monitor and model the volcanic and seismological processes. I demonstrate in this thesis the first use of a Fourier-Transform spectrometer combined with Fiber Bragg Sensors in a field configuration to achieve extremely high precision measurement on earth's crustal deformation. Precisions of thirty nanostrains on a very short base were achieved in the Low-Noise Underground Laboratory (LSBB) at Rustrel. Crustal monitoring opens the way for numerous applications especially in geophysics. A second study presented in this thesis aims at benchmarking several strain sensors based on optical fiber Bragg grating. For this purpose, two reinforced concrete beams have been tested in three points bending up to ultimate limit state.
156

Aplicação de sensores à fibra óptica no monitoramento térmico de painel fotovoltaico / Fiber optic sensor application in the monitoring of photovoltaic panel

Santolin, Edson Antonio 12 August 2016 (has links)
Neste trabalho foi estudada a aplicação das redes de Bragg em fibra óptica, como sensores no monitoramento e mapeamento térmico de um painel fotovoltaico instalado em ambiente aberto. Também foi analisada a capacidade desses sensores em detectar anomalias elétricas do painel, as quais são manifestadas pelas mudanças na temperatura. Devido ao fato de ser pioneiro no estudo da fibra óptica em painéis fotovoltaicos, o presente trabalho buscou comparar os resultados alcançados por esta tecnologia com os dados das demais técnicas de medição de temperatura, como por exemplo, o PT100 e câmera IR. Os ensaios foram realizados utilizando um painel fotovoltaico instalado em ambiente aberto, onde as suas variações de temperatura foram medidas por 27 sensores de fibra óptica instalados em sua superfície frontal. Durante todos os ensaios as condições ambientais de temperatura ambiente, nível de radiação solar e velocidade do vento foram monitorados. Os resultados demonstraram potencialidade de utilização das redes de Bragg em fibra óptica na detecção de variações térmicas ocasionadas por fatores ambientais ou aquecimento nas células. / This paper has been studying the applications of Bragg gratings in optical fibers, as sensors for thermal mapping and monitoring on photovoltaic panel surface which was installing in an open environment. We also analyzed the ability of optical fibers sensors to detect electrical anomalies in the panel, which are manifested by the changes in its temperature. Because it was pioneering in study of optical fiber application into photovoltaic panel, this paper's objective is compare the results between this technology and the other techniques for temperature measurements, for example when are used the PT100 sensors or infrared camera. Assays were performed using a photovoltaic panel that is installed in an open environment, its temperature changes were measured by a total of 27 optical fiber sensors installed on the front surface. During the tests, the environmental conditions of temperature, level of solar radiation and wind speed, were monitored. The results demonstrate the potential use of Bragg gratings in optical fiber for detecting thermal fluctuations caused by environmental factors or by heating the cells.
157

Ferramenta computacional para aquisição de dados de interrogadores ópticos e detecção de pico

Janzen, Frederic Conrad 26 October 2012 (has links)
Sensores óticos baseados em redes de Bragg em fibras óticas estão se tornando uma tecnologia madura e ganhando espaço nas indústrias das mais diversas áreas. Para tal, essa tecnologia deve estar adaptada para ser integrada facilmente ao meio industrial. Com base nisso esta pesquisa apresenta o desenvolvimento de uma ferramenta computacional para duas tecnologias de interrogação de sensores baseados em Redes de Bragg em fibras óticas (FBGs). Além de adquirir os dados dos interrogadores a ferramenta computacional tem por objetivo processar os dados, para isso foi necessário o desenvolvimento de um algoritmo de detecção de picos. Este trabalho também apresenta os resultados obtidos de comparações entre as ferramentas comerciais para cada tecnologia de interrogação e a ferramenta desenvolvida durante esta pesquisa. / Optical sensors based on Fiber Bragg Gratings technologies are becoming a mature technology and starting to com now in the industrial area. To make this possible this technology need to be adapted to be easily integrated in the existing industrial systems. Based on this considerations, this research presents the development of a computational tool for two Fiber Bragg Gratings interrogation technologies. In addition to acquiring data from the interrogator the computational tool is intended to process the data, and this makes necessary to develop a peak detection algorithm. This work also presents the results obtained by comparing the commercial software’s of each interrogation system to the computational toll developed during this research.
158

Aplicação de sensores à fibra óptica no monitoramento térmico de painel fotovoltaico / Fiber optic sensor application in the monitoring of photovoltaic panel

Santolin, Edson Antonio 12 August 2016 (has links)
Neste trabalho foi estudada a aplicação das redes de Bragg em fibra óptica, como sensores no monitoramento e mapeamento térmico de um painel fotovoltaico instalado em ambiente aberto. Também foi analisada a capacidade desses sensores em detectar anomalias elétricas do painel, as quais são manifestadas pelas mudanças na temperatura. Devido ao fato de ser pioneiro no estudo da fibra óptica em painéis fotovoltaicos, o presente trabalho buscou comparar os resultados alcançados por esta tecnologia com os dados das demais técnicas de medição de temperatura, como por exemplo, o PT100 e câmera IR. Os ensaios foram realizados utilizando um painel fotovoltaico instalado em ambiente aberto, onde as suas variações de temperatura foram medidas por 27 sensores de fibra óptica instalados em sua superfície frontal. Durante todos os ensaios as condições ambientais de temperatura ambiente, nível de radiação solar e velocidade do vento foram monitorados. Os resultados demonstraram potencialidade de utilização das redes de Bragg em fibra óptica na detecção de variações térmicas ocasionadas por fatores ambientais ou aquecimento nas células. / This paper has been studying the applications of Bragg gratings in optical fibers, as sensors for thermal mapping and monitoring on photovoltaic panel surface which was installing in an open environment. We also analyzed the ability of optical fibers sensors to detect electrical anomalies in the panel, which are manifested by the changes in its temperature. Because it was pioneering in study of optical fiber application into photovoltaic panel, this paper's objective is compare the results between this technology and the other techniques for temperature measurements, for example when are used the PT100 sensors or infrared camera. Assays were performed using a photovoltaic panel that is installed in an open environment, its temperature changes were measured by a total of 27 optical fiber sensors installed on the front surface. During the tests, the environmental conditions of temperature, level of solar radiation and wind speed, were monitored. The results demonstrate the potential use of Bragg gratings in optical fiber for detecting thermal fluctuations caused by environmental factors or by heating the cells.
159

Ferramenta computacional para aquisição de dados de interrogadores ópticos e detecção de pico

Janzen, Frederic Conrad 26 October 2012 (has links)
Sensores óticos baseados em redes de Bragg em fibras óticas estão se tornando uma tecnologia madura e ganhando espaço nas indústrias das mais diversas áreas. Para tal, essa tecnologia deve estar adaptada para ser integrada facilmente ao meio industrial. Com base nisso esta pesquisa apresenta o desenvolvimento de uma ferramenta computacional para duas tecnologias de interrogação de sensores baseados em Redes de Bragg em fibras óticas (FBGs). Além de adquirir os dados dos interrogadores a ferramenta computacional tem por objetivo processar os dados, para isso foi necessário o desenvolvimento de um algoritmo de detecção de picos. Este trabalho também apresenta os resultados obtidos de comparações entre as ferramentas comerciais para cada tecnologia de interrogação e a ferramenta desenvolvida durante esta pesquisa. / Optical sensors based on Fiber Bragg Gratings technologies are becoming a mature technology and starting to com now in the industrial area. To make this possible this technology need to be adapted to be easily integrated in the existing industrial systems. Based on this considerations, this research presents the development of a computational tool for two Fiber Bragg Gratings interrogation technologies. In addition to acquiring data from the interrogator the computational tool is intended to process the data, and this makes necessary to develop a peak detection algorithm. This work also presents the results obtained by comparing the commercial software’s of each interrogation system to the computational toll developed during this research.
160

Difração Bragg-Superficie (BSD) : uma sonda de alta resolução para o estudo da implantação de íons em semicondutores / Bragg-Surface diffraction (BSD) : high resolution microprobe to study ion implanted semiconductors

Orloski, Renata Villela 05 December 2006 (has links)
Orientador: Lisandro Pavie Cardoso / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica "Gleb Wataghin" / Made available in DSpace on 2018-08-06T14:37:07Z (GMT). No. of bitstreams: 1 Orloski_RenataVillela_D.pdf: 9544671 bytes, checksum: 925b3429c72cbe20c4e9a671e779ed5c (MD5) Previous issue date: 2006 / Resumo: Neste trabalho, a difração Bragg-Superfície (BSD), um caso especial da difração múltipla de raios-X, foi usada como uma microssonda de superfície com resolução para a detecção de defeitos originados próximos da interface cristal-amorfo (c-a) em junções rasas de B em Si, e uma nova técnica de caracterização de semicondutores (GaAs) submetidos à implantação com íons de Si. A varredura Renninger é o registro da intensidade de raios-X difratada pelos planos, normalmente paralelos à superfície de um monocristal, em função da rotação ö em torno da normal à esses planos. Ela exibe picos como contribuições da rede da matriz, e no nosso caso, se o feixe difratado propaga-se paralelamente aos planos, os picos são chamados de difração Bragg-Superfície (BSD), e mostrou-se, pela primeira vez, que essa difração carrega informações sobre a interface c-a. Contribuições da região implantada nas junções rasas, detectadas na varredura para a rede da matriz (picos híbridos), permitiram determinar a presença de Si intersticial, responsável pela difusão do B, e estimar a profundidade da junção de B em Si pré-amorfizado com íons de F, confirmando resultado encontrado por espectroscopia de massa de íons secundários (SIMS). O estudo do efeito da energia e densidade de corrente de implantação, e da energia térmica conduziu às melhores condições para a otimização do processo de recristalização da rede e difusão do dopante, visando a obtenção das junções rasas. Já o mapeamento da condição de difração dos picos BSD foi importante na observação direta da recristalização e difusão do dopante. Parâmetros de rede e perfeição cristalina foram determinados na superfície da matriz GaAs(001) com dfiração múltipla e a simulação dos picos BSD mostrou que menores doses de implantação de íons Si causam os maiores defeitos no plano da superfície do GaAs, o que não acontece com as altas doses pelo efeito da intensa amorfização próximo à interface c-a. O mapeamento dos casos BSD mostraram sensibilidade suficiente para a detecção da formação da região implantada em função da dose nas amostras de GaAs implantadas com Si / Abstract: In this work, the Bragg-Surface Diffraction (BSD), a special case of the X-ray Multiple Diffraction, was used as a surface microprobe with resolution to detect the defects created close to the crystal-amorphous (c-a) interface in shallow junctions of B in Si, as well as a novel technique for characterization of semiconductors (GaAs) under Si ions implantation. Renninger scan is the record of the X-ray intensity diffracted by the planes, normally parallel to the single crystal surface, as a function of the ö rotation around the normal to these planes. It exhibits peaks as matrix lattice contributions and, in our case, if the diffracted beam is propagated along the planes, the peaks are called Bragg-Surface Diffraction (BSD) and, one has shown, by the first time, that this diffraction carries information on the c-a interface. Contributions from the shallow junction implanted regions, detected in the matrix lattice scan (hybrid peaks), allowed to determine the presence of interstitial Si, that is responsible for the B diffusion, and to estimate the B junction depth in Si pre-amorphizied by F ions. This result confirms that found by Secondary Ion Mass Spectroscopy (SIMS). The study of the effect of the energy and implantation current density as well as the thermal energy allowed to determine the best conditions for the optimization of the doping diffusion and lattice recrystallization process, aiming to the shallow junction preparation. On the other hand, the mapping of the BSD peak diffraction condition gave rise to the direct observation of both processes (recrystallization and diffusion). Lattice parameters and crystalline perfection were determined on the GaAs(001) matrix surface by using Multiple Diffraction and the BSD peak simulation has shown that low implantation doses of Si ions has caused strongest damages on the GaAS surface plane. To the contrary, in high doses this effect is strongly reduced by the intense amorphization close to the c-a interface. The BSD mappings have shown enough sensitivity to detect the implanted region formation as a function of the Si implantation dose in GaAs samples / Doutorado / Física da Matéria Condensada / Doutor em Ciências

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