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Projeto de antena de microfita com polarização circular para aplicação em veículos aéreos não tripulados / Design of microstrip antenna with circular polarization for application in unmanned aerial vehicleAraújo, Alexandre de Moraes 28 February 2018 (has links)
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Previous issue date: 2018-02-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Demand in wireless networks has increased considerably in recent years.
Consequently, the study of system components has also increased. Within this
context, antennas are fundamental elements in the physical layer in radiofrequency
communications, and their study has become a research area with great advances.
The need in certain systems for smaller antennas and more adaptability in the space
makes the microstrip antennas in potential substitutes of the traditional antennas.
This work aims to find prototypes of microfite antennas that have physical and
electrical characteristics, such as gain and polarization, superior to the commercial
antennas of a FPV communication system (First Person View) operating at 5.8 GHz.
The methodology used in this research consists of a theoretical survey about circular
polarization antennas, design, simulate and construct these antennas using different
substrates in order to verify their performance and to ship them in an FPV system.
The results obtained through the simulation are compared with the experimental
results in order to attest to the model in question based on the literature used in this
work. Preliminarily, the simulated and measured results show that the Triangular
Patch Antennas have all the desirable characteristics for operation in the FPV
system, being possible to board them for the obtaining of images and analysis of the
performance of the system / A demanda em redes de comunicação sem fio tem aumentado consideravelmente
nos últimos anos. Consequentemente, o estudo dos componentes dos sistemas
também aumentou. Dentro desse contexto, as antenas são elementos fundamentais
na camada física em comunicações via radiofrequência, e o seu estudo tornou-se uma
área de pesquisa com grandes avanços. A necessidade em determinados sistemas
por antenas de menor porte e mais adaptabilidade no espaço tornam as antenas
de microfita em potenciais substitutos das antenas tradicionais. Diante disso, esse
trabalho objetiva encontrar protótipos de antenas de microfita que possuam características
físicas e elétricas, como ganho e polarização, superiores às antenas comerciais
de um sistema de comunicação em FPV (First Person View), operando em 5.8
GHz. A metodologia utilizada nessa pesquisa consiste em um levantamento teórico
acerca das antenas de polarização circular, projetar, simular e construir estas antenas
utilizando diferentes substratos a fim de verificar seu desempenho e embarcá-las
em um sistema FPV. Os resultados obtidos através da simulação são comparados
com os resultados experimentais a fim de atestar o modelo em questão com base
na literatura empregada neste trabalho. Preliminarmente, os resultados simulados e
medidos mostram que as Antenas Patch Triangular possuem todas as características
desejáveis para operação no sistema FPV, sendo possível embarcá-las para a obtenção
de imagens e análise de desempenho do sistema com as mesmas / 2018-06-11
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Conception d'un patch transdermique intelligent pour le monitoring et l'aide à la prise de médicament / Design of transdermal patch for monitoring and drug deliveryTalbi, Yassine 11 June 2018 (has links)
La surveillance personnalisée est une ambition émergente pour les technologies de la santé qui répond aux besoins des patients et des professionnels de santé. L'objectif de ce travail est d'aller jusqu’aux soins, en utilisant un actionneur télécommandé pour mettre en œuvre automatiquement une prescription médicamenteuse. Un système transdermique intelligent est conçu, sous la forme d’un patch, pour administrer de manière contrôlée des médicaments. Des expérimentations sont réalisées pour démontrer l’intérêt des techniques d’aide à la diffusion en termes de contrôle et d’amélioration de la quantité délivrée. Le contrôle de la dose administrée est corrélé à l’actionneur intégré via une loi de commande. Une modélisation et une simulation numérique de la diffusion transdermique est mise en place en liaison avec les résultats obtenus lors d’expérimentations sur une cellule de Franz, ce modèle est appliqué sur une structure planaire "patch classique". Différents scénarios de stimulations électriques et de facteurs de formes ont été conduits pour obtenir un profil d’administration optimal. La conception du système électronique est présentée d’adapter la dose administrée selon les besoins du patient est présentée. Un premier prototype est réalisé, intégrant des fonctions d’actionnement, et de récupération de données issues de capteurs intégrés. / Personalized monitoring is an emerging ambition for health technologies responding the needs of patients and healthcare professionals. In this regard, the purpose of this work is to propose a e-health care device offering active control and permanent actuating link able to control the amount of drug delivered. A first part presents our motivations related to the problems of the aging of the population, recalls the current approaches for the monitoring of the elderly and describes the need in the systems of actuations in particular for the aid to the taking of drugs. From these needs, a state of the art is proposed on the techniques for controlling the delivery of drugs. Experiments are carried out to demonstrate the efficiency of diffusion techniques controlling and improving the quantity delivered. The control of the administered dose is correlated to the integrated actuator via a control command. We present a modeling and a numerical simulation of the transdermal diffusion related to the results obtained during experiments on a Franz cell, and the transposition of the model on a planar structure. Different scenarios of electrical stimulations and shape factors have been conducted to obtain optimal administration profile. Finally, the last part is devoted to technological locks and to the design of the intelligent system which adapt the dose administered according to the needs of the patient. A prototype is made, integrating actuation functions, and data recovery from integrated sensors.
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PROJETO DE ANTENAS E SUPERF?CIES SELETIVAS DE FREQU?NCIA A PARTIR DE TRANSFORMA??ES POLARESOliveira, Maciel Alves de 02 1900 (has links)
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Previous issue date: 2017-02 / Desde os prim?rdios da civiliza??o humana, o homem desenvolve diferentes formas e meios de se comunicar. O fim do s?culo XX e in?cio do s?culo XXI foi marcado pela evolu??o das comunica??es sem fio. Hoje em dia, as vidas econ?micas, sociais e cotidianas das pessoas est?o diretamente conectadas, dependentes e modificadas com o surgimento de novas tecnologias sem fio, sendo a antena um dos principais dispositivos dessas tecnologias sem fio. Esse documento descreve o projeto de antenas, arranjos de antenas e superf?cies seletivas de frequ?ncia por meio de transforma??es polares. As transforma??es geom?tricas obtidas a partir de fun??es polares assemelham-se de certa forma aos fractais nos seguintes aspectos: sua defini??o matem?tica ? simples; o processo de gera??o de uma figura polar ? iterativo; e conforme o n?mero de itera??es aumenta, o per?metro de um elemento polar aumenta, enquanto sua ?rea total ocupada permanece constante. O uso das transforma??es polares no projeto de antenas e superf?cies seletivas de frequ?ncia (FSS) possibilita o desenvolvimento de dispositivos decorativos e camuflados. Os arranjos de antena patch foram constru?dos com elementos dissimilares agrupados nas configura??es de arranjo unidimensional com elementos 1 x 2 e 1 x 4. A fim de aumentar a largura de banda dos arranjos para cobrir a banda 2,400-2,483 GHz requerida em aplica??es IEEE802.11b, g, os valores dos raios dos elementos patch dissimilares foram escolhidos para obter frequ?ncias ressonantes ligeiramente deslocadas. As simula??es foram realizadas com o software comercial ANSYS? Designer?, e os resultados comparados com resultados experimentais, observando-se uma boa concord?ncia entre os mesmos. Os arranjos dissimilares propostos apresentaram uma largura de banda de imped?ncia maior que a de projeto de 83,5 MHz. Propriedades de irradia??o apresentadas endere?ado pelo arranjo 1 x 2 foram combinadas para sintetizar o diagrama de ganho atrav?s de configura??o do arranjo 1 x 4. Outro dispositivo desenvolvimento foram as superf?cies seletivas de frequ?ncia a partir de transforma??es polares inclusive uma FSS dual-band operando nas faixas das redes locais sem fio nas frequ?ncias de 2.45 GHz e 5.8 GHz.
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Controle neuroendócrino da reprodução: fatores que modulam a atividade de neurônios GNRH e kisspetina. / Neural control of reproduction: neuromodulators of GnRH and kisspeptin neurons activity.Marina Augusto Silveira 30 May 2017 (has links)
Neurônios GnRH e kisspeptina representam as populações neuronais de maior importância no controle da reprodução. Estradiol liga-se ao seu receptor expresso pelos neurônios kisspeptina para regular a libertação de GnRH. No modelo animal OVX+E a atividade do neurônio GnRH e pico de LH é depende do estradiol e hora do dia. Nesse estudo, embora a taxa de disparo dos neurônios GnRH seja similar entre os grupos, o padrão dos potenciais revelou uma mudança para maior duração do estouro em camundongos no proestrous, além do fato de uma maior resposta da hipófise. A prolactina tem grande impacto na modulação do eixo HPG e kisspeptina são mediadores dos efeitos da prolactina sobre a reprodução. Uma pequena porcentagem de neurônios de kisspeptina do AVPV foi indiretamente despolarizada pela prolactina. Este efeito requeria a via de sinalização PI3K. Camundongos portadores de inativação de Stat5a/b em células kisspeptina exibiram um início precoce de ciclicidade estro, indicando que os fatores de transcrição STAT5 exercem um efeito inibitório sobre o momento da puberdade. / GnRH and kisspeptina neurons represent the most important neuronal populations in the control of reproduction. Estradiol binds to its receptor expressed by the kisspeptina neurons to regulate the release of GnRH. In the animal model OVX+E the activity of the GnRH neuron and LH surge is dependent of estradiol and time of day. In this study, although the firing rate of GnRH neurons was similar between groups, the pattern of potentials revealed a change to longer burst duration in mice in proestrous, and the pituitary response was greater in this group. Prolactin has impact on HPG axis modulation and kisspeptin is a mediator of the effects of prolactin on reproduction. A small percentage of AVPV kisspeptin neurons were indirectly depolarized by prolactin. This effect required the PI3K signaling pathway. Mice bearing Stat5a/b inactivation on kisspeptin cells exhibited an early onset of estrus cyclicity, indicating that STAT5 transcription factors exert an inhibitory effect on the time of puberty.
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Conception et application de nouveaux outils photochimiques pour l’étude des récepteurs canaux P2X / Conception and application of new photochemical tools to study P2X receptorsPeverini, Laurie 02 November 2017 (has links)
Les récepteurs P2X (P2XR), activés par l’ATP, sont impliqués dans des rôles physiopathologiques. Leur fonctionnement est associé à différents états conformationnels. Le projet de thèse a mené à associer la synthèse organique et l’application de molécules photo-activables avec des techniques d’électrophysiologie patch-clamp, pour décortiquer les mouvements moléculaires de ces récepteurs et effectuer des relations structure-fonction, via trois stratégies : - La synthèse et application d’agrafes photo-isomérisables qui permet le photo-contrôle des P2XR et l’étude de mouvements - La synthèse et caractérisation d’un acide aminé (aa) photo-clivable pour étudier les implications de zones sur la fonction des P2XR via une photolyse - L’incorporation d’un aa non naturel dans les P2XR pour étudier des interactions et mouvements via un « photo-pontage ». Nous avons élucidé les mécanismes moléculaires responsables de la perméabilité des P2XR, récusé l’existence de l'état dilaté et identifié un cation organique physiologique pouvant les traverser. Nous avons aussi conçu un acide aminé photo-clivable pouvant mener à des études structure-fonction des P2XR. / P2X receptors are cationic ligand-gated ion channels, activated by extracellular ATP, involved in many physio-pathological roles. Their function is associated with different allosteric states. During this PhD, we have designed three new strategies, spanning photochemical organic synthesis and patch-clamp electrophysiology to elucidate the molecular mechanisms involved in these conformational states and to collect data in order to study structure-function relationships. - Synthesis and application of molecular tweezers, which allows the photo-control of P2X Rand the study of molecular motions - Synthesis and characterization of a photo-cleavable amino acid with the aim of incorporating it into P2XR and doing structure-function relationships - Incorporation of an unnatural amino acid for photo-crosslinking studies. We have been able to probe the molecular mechanism involved in large organic cations permeation of P2XR, to bring into question the dilated state and to identify a physiological cation that can flow through P2XR. We have also designed a photo-cleavable amino acid which could serve in the study of structure-function relationships.
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Evaluation ultrasonore des réparations de structures métalliques par collage de patchs compositesLe Crom, Bénédicte 10 May 2010 (has links)
Cette thèse s’est déroulée dans le contexte de l’évaluation non destructive du collage de patches composites employés pour la réparation de structures aéronautiques. Le besoin a été exprimé par la DGA Techniques Aéronautiques (Toulouse). Le travail effectué a consisté en l’exploitation des ondes guidées, de type SH puis Lamb, pour mesurer des caractéristiques mécaniques d'un joint de colle et tenter d’évaluer, de manière non destructive, la qualité du collage. Dans un premier temps, les propriétés viscoélastiques des matériaux assemblés sont déterminées. Elles servent alors de données d’entrée à des modèles, basés sur la méthode SAFE (Semi Analytical Finite Element method), permettant d’obtenir les courbes de dispersion ainsi que les champs des différents modes guidés se propageant le long de l’assemblage collé. Ces simulations numériques permettent alors d’évaluer le potentiel des ondes guidées à caractériser un adhésif. Des mesures expérimentales sont ensuite menées pour confirmer les prédictions numériques. Finalement la résolution d’un problème inverse, qui consiste à évaluer les modules de rigidité de la couche de colle se situant entre une plaque d’aluminium et un patch, est proposée pour établir des pistes d’évaluation non destructive d’un collage répondant au besoin industriel. Cette étude a été financée par la DGA, France. / Repairing of metallic structures using composite patches bonded with an adhesive layer is more and more common in the aeronautic field, and particularly at DGA Techniques Aéronautiques. In order to guarantee the quality of this bond, the sensitivity of ultrasonic guided waves is investigated. Shear-horizontally polarized (SH) waves, and Lamb waves are investigated to infer the stiffness of the adhesive layer. The SAFE method is used to predict the dispersion curves and mode shapes of the different wave modes propagating along the three-layer assembly. Numerical simulations are run for selecting the most appropriate wave modes, i.e. with higher sensitivity to the stiffness of the bond than to other components properties. Experiments are also made for generating-detecting pre-selected SH or Lamb wave modes in order to confirm the numerical predictions. Finally the resolution of an inverse problem, consisting in the evaluation of the stiffness modulus of the bond layer between an aluminium plate and a carbon-epoxy composite patch, at different curing time, is proposed as a contribution to the establishment of possible strategies for bonds testing. This work was supported by DGA, France.
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Výpočet frekvenčně-admitančních charakteristik z naměřených patchclampových dat / Evalution of Frequency-Admittance Characteristics from Meausured Patch Clamp DataPodhorský, Jiří January 2011 (has links)
The goal of diploma these is ‘Calculation of frequency-admittance characteristics from measured patchlamps dates’. Calculation is made on the basis of study of mentioned problematic measure ion current cell membrane by patch-clamp method and its using for measure frequency-admittance characteristics. After it selected method of calculation was realized in software calculator Matlab.
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Dynamique intracellulaire des cellules pyramidales de CA3 dans l'hippocampe pendant les états de veille / Intracellular dynamic of CA3 pyramidal cells of the hippocampus during awake statesMalezieux, Meryl 07 December 2018 (has links)
Les états de veille sont composés d’états cérébraux distincts, corrélés avec différents comportements et caractérisés par des oscillations spécifiques observables dans le potentiel de champ local (Local Field Potential, LFP). Bien que les différents états cérébraux et leur signature dans le LFP aient été caractérisés, les mécanismes cellulaires sous-jacents restent à ce jour peu connus. Des changements des propriétés de neurones uniques seraient corrélés avec, et pourraient participer à la génération de ces changements d’états cérébraux. L’activité coordonnée et synchronisée de neurones facilite certains processus cognitifs tels que la mémoire. L’hippocampe joue un rôle essentiel dans les mémoires spatiale et épisodique, et dans l’hippocampe, CA3 est important pour la formation d’associations facilitant l’encodage rapide de la mémoire. De plus, les informations provenant du cortex entorhinal, du gyrus denté, et de CA3 même sont comparées et intégrées dans CA3 avant d’être transmises à CA1. Lors de périodes de repos, le LFP hippocampique présente une activité large et irrégulière (Large Irregular Activity, LIA), ponctuée par des oscillations plus rapides, les sharp-wave ripples, jouant un rôle dans la consolidation de la mémoire. Lors de périodes exploratoires, le LFP hippocampique oscille aux fréquences theta (6-12 Hz) et gamma (30-100 Hz). Les cellules pyramidales (CP) de CA3 jouent un rôle important dans chacun de ces états ; elles sont nécessaires pour les sharp wave lors de périodes de repos, et les oscillations gamma lors de comportements exploratoires. Dans le but d’étudier les modulations intracellulaires des CP de CA3, nous avons réalisé des enregistrements de patch-clamp en configuration cellule entière chez l’animal éveillé. Nous avons associé ces enregistrements avec des mesures du diamètre pupillaire et de la vitesse de locomotion de l’animal, ainsi qu’avec l’enregistrement de l’activité oscillatoire du LFP dans l’hippocampe. Nos résultats montrent que certaines CP de CA3 sont sensibles à la modulation intracellulaire lors de différents rythmes hippocampiques, et ont tendance à diminuer leur potentiel de membrane moyen, leur excitabilité, leur variance et leur décharge de potentiel d’action lors des oscillations theta par rapport aux périodes de LIA. De futures études permettront de déterminer si ces changements sont dus à des changements d’entrées synaptiques et/ou de neuromodulateurs. Ces modulations pourraient jouer un rôle dans l’émergence des rythmes oscillatoires du LFP, et permettre à CA3 de réaliser différentes fonctions mnésiques à différents moments. / Wakefulness is comprised of distinct brain states, correlated with different behaviors and characterized by specific oscillatory patterns in the local field potential (LFP). While much work has characterized different brain states and their LFP signatures, the underlying cellular mechanisms are less known. Changes in single cell properties are thought to correlate with and possibly result in these changes in brain state. Synchronized and coordinated activity among distributed neurons supports cognitive processes such as memory. The hippocampus is essential for spatial and episodic memory, and within the hippocampus, area CA3 is important for rapid encoding of one-trial memory. Additionally, CA3 is the site where information from the entorhinal cortex, dentate gyrus, and CA3 itself is compared and integrated before output to CA1. During quiet wakefulness, the hippocampal LFP displays large irregular activity (LIA) punctuated by sharp-wave ripples, which play a role in memory consolidation. During exploratory behaviors, hippocampal LFP oscillates at both theta and gamma frequencies. CA3 pyramidal cells (PCs) play an important role in each of these brain states; they are necessary for both sharp waves during quiet wakefulness and for gamma oscillations during exploratory behavior. We explored the changes that occur in the intracellular dynamics of CA3 PCs during changes in brain state, by using whole-cell patch-clamp recordings from CA3 PCs in awake head-fixed mice. We combined those recordings with measurements of pupil diameter, treadmill running speed and LFP recordings of oscillatory activity. Our findings show that some CA3 PCs are prone to intracellular modulation during brain rhythms, and tend to decrease their average membrane potential, excitability, variance and output firing during theta as compared to LIA. Future studies will demonstrate whether these effects are due to changes in synaptic and/or neuromodulatory inputs. This modulation at the single-cell level in CA3 could play a role in the emergence of oscillations, and underlie the ability of CA3 to perform different memory functions during different brain states.
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Design Of Dual Polarized Wideband Microstrip AntennasYildirim, Meltem 01 June 2010 (has links) (PDF)
In this thesis, a wideband dual polarized microstrip antenna is designed, manufactured and measured. Slot coupled patch antenna structure is considered in order to achieve the wideband characteristic. Although rectangular shaped slot coupled patch antennas are widely used in most of the applications, their utilization in dual polarized antenna structures is not feasible due to space limitations regarding the positioning of two separate coupling slots for each polarization. For a rectangular slot, the parameter that affects the amount of coupling is the slot length. On the other hand when a H-shaped slot is considered, both the length of the center arm and the length of the side legs determine the coupling efficiency. This flexibility about the optimization parameters of the H-shaped slot makes it possible to position the two coupling slots within the boundaries of the patch antenna. Therefore, H-shaped slot coupled patch antennas are studied in this thesis. In order to investigate the effects of slot and antenna dimensions on the radiation characteristics of the antenna, a parametric study is performed by analyzing the antenna structure with a planar electromagnetic field simulation software (Ansoft Designer). By the help of the experience gained through this parametric study, a dual polarized patch antenna that can be used at the base station of a cellular system (DCS: 1710&ndash / 1880 MHz) is designed. Before manufacturing the antenna, dimensions of the antenna are re-tuned by considering a finite sized ground plane in the simulations. Finally, the antenna is manufactured and measured. An acceptable agreement is obtained between the measurement and the simulation results.
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Engineering of Light-Gated Artificial Ion ChannelsSteller, Laura Florentina 26 January 2007 (has links) (PDF)
The goal of this project is the development of artificial ion channels that can be actuated by light and thus controlled efficiently. Our artificial system is composed of two regions: the gate and the body part. The gate part is based on light-responsive azo groups while the body part is formed by calix[4]resorcinarene. Key of controlling mechanism is the conformational change between cis and trans isomers, which is translated into movement of the gate. Light-gated artificial ion channels are aimed at eliminating of the stochastic mechanism of artificial ion channels. Such a reversible photocontrol should be a powerful tool for using artificial ion channels as the basis for the development of new pharmaceuticals and drug delivery systems, as photoswitches, and in the field of microfluidics.
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