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Giralt, Mireille. "Adaptation d'un modèle de décharge en vue de son application à la conception de l'isolation aérienne H. T. Et T. H. T". Ecully, Ecole centrale de Lyon, 1999. http://www.theses.fr/1999ECDL0033.
Pełny tekst źródłaDucrocq, Julien. "Vision catadioptrique pour favoriser la perception d'environnements hétérogènes". Electronic Thesis or Diss., Amiens, 2022. http://www.theses.fr/2022AMIE0067.
Pełny tekst źródłaThis thesis presents the conception methods of two catadioptric cameras capable of recording usable images of heterogeneous environments. These cameras belong to the adaptive vision field, which gathers the cameras of which the optics or sensor have heterogeneous properties which can vary across time. Adaptive cameras abilities include capturing heterogenous environments which physical or geometrical properties change across space. This thesis proposes a survey of the state of the art on adaptive cameras which are able to capture specific types of heterogenous environments. On the one hand, we consider the scenes characterized by a spatial variation of radiances, with a dynamic range around 120 decibels. These scenes put conventional cameras in difficulty, their images have some pixels saturated and others to dark, because of their low dynamic range. In both casses, these image regions does not carry any visual information about the scene, they are not usable. In order to capture the radiances corresponding to these bright and dark areas, the high dynamic range cameras (HDR) are used. Nonetheless, there is no available HDR panoramic camera yet. Therefore, the first contribution of this thesis is the conception of an HDR panoramic camera in order to improve robots navigation, with only visual perception, in outdoor scenes with various. Mounted on a mobile robot, this camera enlarges the convergence domain and the positioning accuracy of a robot by direct visual servoing, outdoors. On the other hand, we consider the scenes which have a non-uniform level of details across space : some scene elements carry more visual information than the others. To capture such heterogeneous environments, the second contribution of this thesis is an adaptive camera. This camera is based on a new deformable mirror of local curvatures allowing to enlarge or reduce the number of pixels occupied by scene regions in the image. This camera, nicknamed Visadapt, capture multi-résolution images which depend on scene content. From one scene to another, the shape of the mirror may be changed to optimise the resolution of the images captured to this new scene. The surface of the mirror is made of material both reflective and deformable, the mylar, and changes of shape thanks to a grid of linear actuators placed underneath. This mirror, plan as an initial state, is able to change shape to give to the scene regions captured by Visadapt the desired resolution in the image. The characteristics of Visadapt, particularly the dimensions, the materials of its different elements and the actuators pitch, have been defined thanks to a simulation study. A real prototype have been built to respect the parameters defined by the simulation. The experiments shown that this prototype is able to magnify up to four scene regions at once. This thesis ends with a conclusion presenting future works to upgrade the prototypes of the two cameras, in order to enhance their performances and the diversity of images they can capture. Furthermore, this conclusion proposes research tracks to improve even further these two cameras and even adaptive vision in general
Kadjo, Aziz. "Micro-capteurs implantables : étude des critères de performance en vue de l'optimisation des acquisitions par spectroscopie RMN in vivo". Thesis, Lyon 1, 2011. http://www.theses.fr/2011LYO10179.
Pełny tekst źródłaThe objective of this thesis is to evaluate the micro-coil performance, in spectroscopy in vivo and provide any improvements, while respecting the constraints in terms of obstruction and biocompatibility imposed by applications on brain of animal models. Therefore, this work had also to assess the sensitivity understanding of these particular micro-sensors, a notion that has not yet been explored. This document is organized into five chapters: the first one is an "overview" of state of art techniques and a reminder of the work already done in terms of production and in relation to different metabolite "targets". Chapter II presents the instrumental developments undertaken to improve the detection: optimization of adaptation in power and noise matching at the spectrometer input, were also taken into account. The difficulty of maintaining the animal model in a reduced space is solved by providing different configurations of remote settings. The introduction of a low-noise preamplifier is also studied and implemented. The important question of the limit of detection is approached from a theoretical point of view in Chapter III. The interest of this analysis is to assess the performance of micro-coil, we will point out that this new concept enables to describe a spectroscopy facility (sensor associated with a spectrometer for a given experiment). A study of enhancement of the limit of detection by the apodization technique will be addressed and validated on spectroscopy acquisitions. Chapter IV is an implementation in the first part, through modelling, to discuss changes in the limit of detection for some structural changes (size and positioning of the micro-coil). In the second part, an implementation of the limit of detection through spectroscopic experiments will be presented in order to compare the performance of existing coils: a commercial coil and a micro-coil. The biocompatibility of implantable micro-coil treated in Chapter V. The completion of this study was carried out upstream of the theoretical and instrumental aspects in chapter III and IV and that helped their development with a more pragmatic approach
Noël, Frédéric. "Mailleur auto-adaptatif pour des surfaces gauches en vue de la conception intégrée". Grenoble INPG, 1994. http://www.theses.fr/1994INPG0110.
Pełny tekst źródłaRaizer, Adroaldo. "Maillage auto-adaptatif dans les logiciels de calcul de champ électromagnétique bidimensionnel et tridimensionnel". Grenoble INPG, 1991. http://www.theses.fr/1991INPG0070.
Pełny tekst źródłaGagnon, Mathieu. "Augmentation du champ de vue d'une caméra temps-de-vol commerciale". Master's thesis, Université Laval, 2019. http://hdl.handle.net/20.500.11794/35378.
Pełny tekst źródłaThis dissertation presents a method to increase the field of view of a commercially available time-of-flight camera. This increase could extend the field of application of such cameras, especially in mobile robotics where awareness of the surrounding is an important factor. The design includes a conversion lens added in front of the optical system and a modification to the illumination system. In the specific case of a Kinect v2, capability of 3D reconstruction has been preserved for an augmentation of 50% of the field of view, from 70°x60° to 106°x86°. To take into consideration the optical modifications, a calibration of the camera has been made. The modified system is characterised by a good precision (<1%) and a good accuracy (<1,5%). These results are calculated on slightly under 40% of the available pixels using 100 acquisitions. Performances decrease at a great rate outside of the central pixel zone. A trade-off has been made on the system performances in order to increase the original field of view.
Baina, Jamal. "Codage hybride adaptatif d'images en vue de la transmission à bas débit : logiciel et matériel". Metz, 1992. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/1992/Baina.Jamal.SMZ924.pdf.
Pełny tekst źródłaImage coding methods are used for low rate transmission. The difference between these methods lies in compression ratio and image subjective quality. We developed a new image coding method based on a visual classifier. A visual vector quantization is applied on the discret cosine transform coefficients, using the correspondance between the image domain and transform domain. A parallel coding system is described here. It's based on digital signal processors and transputers
BAINA, JAMAL TOSSER-ROUSSEY A. "CODAGE HYBRIDE ADAPTATIF D'IMAGE EN VUE DE LA TRANSMISSION A BAS DEBIT : LOGICIEL ET MATERIEL /". [S.l.] : [s.n.], 1992. ftp://ftp.scd.univ-metz.fr/pub/Theses/1992/Baina.Jamal.SMZ924.pdf.
Pełny tekst źródłaViellerobe, Bertrand. "Microscopie en champ proche optique en vue de la spectroscopie de molécules individuelles". Bordeaux 1, 2000. http://www.theses.fr/2000BOR10576.
Pełny tekst źródłaJoyeux, Xavier. "Localisation de nanomatériaux dans des structures en vue d'applications microélectroniques". Grenoble INPG, 2009. http://www.theses.fr/2009INPG0100.
Pełny tekst źródłaThis work concerns the integration of carbon nanotubes and catalytic nanoparticJesin the structures of microelectronics for the development of transistors and interconnections. Ln a first approach, these metal oxide nanoparticles are synthesized and then deposited by chemical interactions on polymer films electrografted on wafers. These catalytic sites with a controlled density are used for the growth of carbon nanotubes in vertical vias. Ln a second approach, nanotubes produced ex-situ are dispersed with surfactants before being functionalized by diazonium salts. These modified nanotubes are deposited bya chemical or an electrochemical method in horizontal trenches. These two innovative and easily reproducible methods allow the selective deposition of nanomaterials in the structures of microelectronics for a very large scale integration
Tejeda, de la cruz Alberto. "Développement d’une méthode d’auto-paramétrage auto-adaptatif pour une pompe à chaleur en vue d’un fonctionnement optimisé". Thesis, Paris Sciences et Lettres (ComUE), 2016. http://www.theses.fr/2016PSLEM088.
Pełny tekst źródłaSetting control parameters of residential double service heat pumps at the time of installation and commissioning is a delicate matter. Indeed, some parameters are not trivial, there are many to be adjusted and the heat pump operations are quite sensitive to the parameters' values. Poor parameterization can lead to suboptimal heat pump operation or even to important dysfunction (harming thermal comfort).Hence, this thesis aims to develop a method for the heat pump to self-adapt the value of its control parameters. The heat pump should modify if required the "default" settings in order to adapt them to the heat emitters, to the building thermal response and to the occupancy (in terms of thermal comfort and DHW needs). For industrial reasons, this method should use on-board sensors.First, the thesis focuses on identifying the key parameters of the heat pump control, i.e. those with greatest influence on the consumption. This leads to the functions which have to be optimized: heating curve adjustment, time of DHW generation, heating setback anticipation. The objective is to maximize the coefficient of performance and minimize the use of electrical back-ups while ensuring comfort. This is achieved by developing optimized control algorithms. Thanks to forecasts models, based on neural networks, we are able to predict on a short term horizon the building thermal response, the DHW availability and the heat pump performances. The developed models and algorithms have been validated through numerical simulations, and we have evaluated the heat pump performances in comparison to a classic control. The proposed solutions were applied and tested during a heating season on a real heat pump installed in a semi-virtual test bench (real weather and virtual building)
Piotrowicz, Stéphane. "Intégration monolithique de HEMT's sur substrat InP en vue de l'amplification de puissance en bande V". Lille 1, 1999. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/1999/50376-1999-253.pdf.
Pełny tekst źródłaCôté, François. "Imagerie de neurones en profondeur par fibre optique avec champ de vue variable et imagerie à grand champ volumétrique rapide avec sectionnement optique HiLo". Master's thesis, Université Laval, 2020. http://hdl.handle.net/20.500.11794/38294.
Pełny tekst źródłaImaging cells and axons in deep brain with minimal damage while keeping a sizable field of view remains a challenge, because it is difficult to optimize one without sacrificing the other. We propose a scanning method reminiscent of laser scanning microscopy to get a reasonable field of view with minimal damage deep in the brain. By using micro-optics at the tip of our 125 µm-diameter singlemode fiber inside a 250 µm capillary, we can create a focal spot on the side of the fiber at a distance of approximately 60 µm. The focal spot has a 2 µm diameter and can be scanned at up to 30 hertz by a custom scanning device over a 90 degree angular sweep on a single line. A piezoelectric actuator moves up and down the fiber to achieve a cylindrical scanning pattern. By having this side illumination, there is no need for surgical exposure of the tissue, making our method simple and easy to achieve. The field of view is controlled by the angular and vertical sweeps, unrelated to the fiber diameter. Furthermore, by modifying the length of the grin lens, we could directly increase or decrease the field of view of our optical system, without any change on the probe diameter. We have succeeded in imaging microglia in the midbrain of a CX3CR1-GFP mouse. The system is also ready for calcium imaging on single pixel lines. Imaging whole mouse brains can provide a wealth of information for understanding neuronal development at both the microscopic and macroscopic scale. Furthermore, visualizing entire brain samples allow us to better conceptualize how different diseases affect the brain as a whole, rather than only investigating a certain structure. Currently, two main challenges exist in achieving whole mouse brain imaging: 1) Long image acquisition sessions (on the order of several hours) and 2) Big data creation and management due to the large, high-resolution image volumes created. To overcome these challenges, we present a fast 1-photon system with a slightly decreased resolution allowing whole brain, optically sectioned imaging on the order of minutes by using a mathematical algorithm termed “HiLo”. Our large field of view (25 mm2 ) allows us to see an entire newborn mouse brain in a single snapshot with a resolution of about 2 µm in lateral direction and 4 µm in axial direction. This resolution still allows visualization of cells and some large axonal projections. This technological advancement will first and foremost allow us to rapidly image large volume samples and store them in a smaller format without losing the integral information, which is mainly stained-cell quantity and location. Secondly, the design will allow for increased successful high-resolution imaging by screening ...
Bonneau, Mathieu. "Échantillonnage adaptatif optimal dans les champs de Markov, application à l'échantillonnage d'une espèce adventice". Toulouse 3, 2012. http://thesesups.ups-tlse.fr/1909/.
Pełny tekst źródłaThis work is divided into two parts: (i) the theoretical study of the problem of adaptive sampling in Markov Random Fields (MRF) and (ii) the modeling of the problem of weed sampling in a crop field and the design of adaptive sampling strategies for this problem. For the first point, we first modeled the problem of finding an optimal sampling strategy as a finite horizon Markov Decision Process (MDP). Then, we proposed a generic algorithm for computing an approximate solution to any finite horizon MDP with known model. This algorithm, called Least-Squared Dynamic Programming (LSDP), combines the concepts of dynamic programming and reinforcement learning. It was then adapted to compute adaptive sampling strategies for any type of MRF distributions and observations costs. An experimental evaluation of this algorithm was performed on simulated problems. For the second point, we first modeled the weed spatial repartition in the MRF framework. Second, we have built a cost model adapted to the weed sampling problem. Finally, both models were used together to design adaptive sampling strategies with the LSDP algorithm. Based on real world data, these strategies were compared to a simple heuristic and to static sampling strategies classically used for weed sampling
NOEL, Céline. "AUTO-STRUCTURATION DE PARTICULES MAGNETIQUES DANS UN CRISTAL LIQUIDE NEMATIQUE : VERS UN NOUVEAU TYPE DE COMPOSITE ADAPTATIF". Phd thesis, Université de Nice Sophia-Antipolis, 2005. http://tel.archives-ouvertes.fr/tel-00011071.
Pełny tekst źródłaMorel, Xavier. "Conception d'une optique électrostatique à champ de vue hémisphérique pour l'étude des plasmas magnétosphériques, terrestre et planétaires". Phd thesis, Université Pierre et Marie Curie - Paris VI, 2012. http://tel.archives-ouvertes.fr/tel-01062842.
Pełny tekst źródłaMaillard, Alain. "Préparation après croissance d'échantillons monodomaines de BaTiO3 en vue d'utilisation optique : mesures holographiques sous champ électrique appliqué". Dijon, 1989. http://www.theses.fr/1989DIJOS005.
Pełny tekst źródłaGuyot, Steve. "Analyse des matrices de Mueller et du champ de speckle en vue d'applications au génie bio-médical". Paris 12, 2003. https://athena.u-pec.fr/primo-explore/search?query=any,exact,990002136440204611&vid=upec.
Pełny tekst źródłaCourtois, Pierre. "Elaboration en creuset froid sous champ magnétique intense de quelques matériaux magnétiques en vue de leur texturation". Université Joseph Fourier (Grenoble), 1995. http://www.theses.fr/1995GRE10124.
Pełny tekst źródłaGuyot, Steve Clairac Bernard Vézien Christelle. "Analyse des matrices de Mueller et du champ de speckle en vue d'applications au génie bio-médical". Créteil : Université de Paris-Val-de-Marne, 2003. http://doxa.scd.univ-paris12.fr:80/theses/th0213644.pdf.
Pełny tekst źródłaDupoux, Céline. "Méthode d'analyse en vue de l'amélioration des interférences électromagnétiques dans les systèmes intégrés radio fréquence". Thesis, Toulouse, INSA, 2011. http://www.theses.fr/2011ISAT0027/document.
Pełny tekst źródłaThe work presented in this PhD suggest a methodology for the study of electromagnetic interference in RF integrated systems. This thesis focuses on the problems of near-field radiated coupling between different parts of a chip or between ICs.Then this methodology is applied to two case studies on different scales, in the first case study the coupling between a 3G power amplifier and a transceiver is presented then a model of the coupling is made reproducing parasitic effects observed in measurements. Then a study to extract and evaluate the coupling between blocks, between a VCO inductor and nearby structures of a microchip. Then a near-field emission model of this circuit is proposed.These works demonstrate the interest of EMC studies in all phases of designing a circuit or system and the interest of near-field measurements that allow the realization of the investigation and diagnosis of EMC
Amodei, Luca. "Etude d'une classe de fonctions splines vectorielles en vue de l'approximation d'un champ de vitesse. Application à la météorologie". Toulouse 3, 1993. http://www.theses.fr/1993TOU30196.
Pełny tekst źródłaDuvanaud, Claude. "Les classes de fonctionnement à haut rendement pour l'amplification de puissance microonde, en vue d'applications spatiales et de radiocommunications mobiles". Limoges, 1993. http://www.theses.fr/1993LIMO0195.
Pełny tekst źródłaGodts-Poubelle, Pascale. "Modélisation et optimisation en vue de réalisations technologiques de M. E. S. F. E. T. Et de T. E. G. F. E. T. AlGaAs/GaAs". Lille 1, 1988. http://www.theses.fr/1988LIL10081.
Pełny tekst źródłaHoàng, Thê Cuong. "Caractérisation des supraconducteurs à haute température critique en vue d'application en électrotechnique". Thesis, Nancy 1, 2010. http://www.theses.fr/2010NAN10129/document.
Pełny tekst źródłaThe main of this thesis is the characterization of high critical temperature superconductors (HTS). First, we have presented the generality of the HTS. The possible use in the future, of the HTS for the transport current, involves to study more particularly the losses in self-field, or fed by a sinusoidal current. Then we have recalled the losses calculations based on the Bean model critical state for various forms of the sample, as a plate, a cylinder, a tube cylindrical hollow and an HTS cable. For the second time, we have characterized the HTS which allows make the characteristics E(J), U(I), Jc(B), and n(B) of an HTS tube cylindrical hollow. The characterization has been made by the electrical method. Then we have tried a self-field compensation of an HTS tube by two different methods. After we have measured the magnetic field diffusion in an HTS plate and we have determined its Jc by the magnetic field measurement in complete penetration. In the last time, we have calculated analytically the losses in self-field of the HTS tube, using the Bean model critical state. We have also showed that in self-field, the magnetic field penetration inside the HTS material happens in order. First of all, there is magnetic field incomplete penetration from outside to inside the material, then when the penetration is complete, the magnetic field increase uniformly throughout the material. These losses calculation results have been compared to measurement results, this comparison shows a clear coincidence. For the last experiment, we have measured and analysed the losses in an HTS coils fed by a sinusoidal current 50Hz frequency. These results have showed that the losses of this HTS coils are mainly losses in the superconducting material and not in the superconducting matrix
Claverie-Rospide, Rémy. "Conception et mise en oeuvre d'un capteur électro-optique en vue de la mesure de grandeurs diverses : (température, champ électrique, etc.)". Metz, 2006. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/2006/Claverie_Rospide.Remy.SMZ0635.pdf.
Pełny tekst źródłaIn this thesis, we introduce a new architecture of an electro-optic sensor allowing the measurement of various parameters such as temperature or electric field. The optical instrumentation is based upon an Sénarmont setup adapted for a reflection use in which, an electro-optic modulator set the operating point and allow a compensation of the shifted phase introduced by the variation of the physical parameter. The sensor mainly consists of a synchronous detector, a PID controller and of a PWN based high voltage amplifier. This electronic part have a settling time of 50 ms and a stability of 2,3 %. The measurement have been made over 8 hours. We show some resultats on temperature variations measurements (sensitivity of 0,91 V/K, resolution of 4. 4 mK, precision of 11 mK) and on electric field measurements ( sensitivity of 2,7 V/V/cm, resolution of 1,5 V/cm, settling time about 50 ms
Claverie-Rospide, Rémy Salvestrini Jean-Paul Fontana Marc. "Conception et mise en oeuvre d'un capteur électro-optique en vue de la mesure de grandeurs diverses (température, champ électrique,etc) /". [S.l.] : [s.n.], 2006. ftp://ftp.scd.univ-metz.fr/pub/Theses/2006/Claverie_Rospide.Remy.SMZ0635.pdf.
Pełny tekst źródłaNoysena, Kanthanakorn. "Astronomie multi-messager avec des télescopes à grand champ de vue : stratégies d'observation, analyse d'images, suivi de candidats, études et implications astrophysiques". Thesis, Toulouse 3, 2020. http://www.theses.fr/2020TOU30120.
Pełny tekst źródłaThe detection of gravitational waves (GWs) from LIGO and Virgo interferometers opened a new era for multimessenger observations especially with the coincident detection between GW events and gamma-ray burst (GRB) detection. The first GW event detected by LIGO on the 14th September 2015 (Abbott et al., 2016d) was a binary black hole merger (BBH). Until August 2017 nine other mergers of black holes were detected during runs O1 and O2. But the most interesting object for multimessenger astronomy was the merger of two neutron stars (BNS) detected on 17th August 2017 (Andreoni et al., 2017). This merger was detected in various electromagnetic waves and allowed to confirm the kilonova model. This research started with the analysis of images recorded by the TAROT telescopes during runs O1, O2 to detect new optical sources associated to black hole mergers. The analysis pipeline was developed to process images and none of optical transient detected but the limiting magnitude of the particular BBH event of 14th August 2017 gave new constraints about the hypothetical link with gamma ray bursts (Noysena et al., 2019). Three GW events; GW150914, GW170104 and GW170814 were observed with TAROT allowing us to constrain alpha < 10^-5, the fraction of energy emitted by gravitational waves converted into optical light. An approximately 100% coverage of localization of GW170814 was observed at 0.6 days after GW triggering with no evidence of optical transient and 65% of 147 optical light curves of GRBs known redshift were excluded. The chance to observe optical transient began when GW interferometers started the run O3 on 1st April 2019 and the campaign ended on 27th March 2020. At the end of run O3, 55 events were detected by LIGO and Virgo and 47 GW events were followed-up by TAROT, thousands of images were searched and analyzed for transient by pipeline using processing techniques described in this manuscript. No new credible optical source associated to GW events was found and 34 GCN circulars reporting optical observations were published to GCN network. The conversion efficiency alpha for BNS, BBH, and NSBH is at 2×10^-6, 3×10^-7 and 2×10^-8 respectively. The limiting magnitude and the short delay to start optical observations allow us to reduce severely the hypothesis of the association between GWs and GRBs in case of BBH mergers. However, we have not enough number of cases to exclude definitively the association. Five binary neutron star mergers were detected before the end of GW observation but none of them was closer than 100 Mpc which is beyond limiting distance where TAROT could detect the associated kilonova. As a consequence, no conclusion to derive any relevant with BNS optical observations. The optical follow up by TAROT was a pioneering experience with a lot of exciting jobs to adjust event after event to increase the efficiency of the detection pipeline. Joining the GRANDMA group brought more opportunity to detect optical transient during run O3 and result in scientific papers published by Antier et al. (2019, 2020). More GW counterparts and optical observations are needed and we are ready to participate to the optical follow-up of the next GW runs
Benabou, Abdelkader. "Contribution à la caractérisation et à la modélisation de matériaux magnétiques en vue d'une implantation dans un code de calcul de champ". Lille 1, 2002. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2002/50376-2002-283.pdf.
Pełny tekst źródłaZbrzeski, Adeline. "Circuits intégrés d’enregistrement et d’analyse en temps réel des potentiels de champ neuronaux : application au traitement de la maladie de Parkinson, par contrôle adaptatif de stimulations cérébrales profondes". Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14328/document.
Pełny tekst źródłaParkinson’s disease is the second most common neurodegenerative diseases throughout theworld. In this context, the research project associated with this thesis is to improve the symptomatictreatment of Parkinson’s disease through the development process of deep brain stimulationadaptive. The work of this thesis is based on the design of an ASIC for recording andprocessing of neural signals, in response to a variety of issues : ongoing treatment and real-timefocus on specific bands of very low-frequency and highly configurable. The goal is to use theprocessed information to the control and generation of a stimulation signal. This ASIC wasdeveloped, characterized and used electronically in a context in vivo. A closed-loop system wasmade from the ASIC, showing functional. These in vivo validations open up many possibilitiesfor investigation of the concept of closed-loop brain stimulation
Martinez, Nicolas. "Formulation faible, formulation forte et méthodes de calcul numérique du champ magnétique en vue de la modélisation d'une prothèse innovante pour l'assistance circulatoire". Phd thesis, Toulouse, INPT, 2008. http://oatao.univ-toulouse.fr/7092/1/martinez_nicolas.pdf.
Pełny tekst źródłaColin, Muriel. "Modélisation d'un réflectomètre mode X en vue de caractériser les fluctuations de densité et de champ magnétique : applications aux signaux de Tore Supra". Nancy 1, 2001. http://www.theses.fr/2001NAN10181.
Pełny tekst źródłaThis work deals with the interaction between a probing wave and plasma fluctuations. For all probing wave polarization in reflectometry expermiments, this interaction can be described by a Mathieu's equation. In order to check the validity domain of our model we have developed softwares with new numerical schems (both in O-mode and X-mode). After these validations, the ratio of the wave amplitude backscattered by density and magnetic fluctuations has been evaluated, and we have confirmed that the density fluctuations are prominent in most of cases in tokamak expermiments. The accuracy of numerical methods is high enough to simulate the reflectometer experiments. The part of coherent fluctuations in 1D is now well determined and a new connection between the spectrum of the phase variations and the turbulence spectrum has been shown
Meng, Nan. "Fabrication et caractérisation de transistors à base de Graphène Nano Ruban en vue d’application haute fréquence". Thesis, Lille 1, 2011. http://www.theses.fr/2011LIL10002/document.
Pełny tekst źródłaIn 2004, a new material, graphene, was isolated for the first time on a SiO2 substrate, using a technique of mechanical exfoliation by KS Novoselov and AK Geim - Nobel Prize in Physics, 2010. This material, which has extraordinary mechanical and electrical properties, has attracted significant research works. Therefore, different methods of synthesis of graphene on grand surface are developed. It is in this context that I began my research in 2007 with the aim of demonstrating the potential of graphene-based transistors for microwave applications. Our choice was oriented toward to the synthesis of graphene by graphitization of SiC. These studies were conducted in close collaboration with the group EPIPHY, as the part of the ANR project Graphene XP-certified in 2007, with support from ST-Microeletronics. Having identified the material properties that affect the characteristics of field effect transistors on this material, I have developed during my thesis technological process for making transistors on such material, as well as a procedure for characterizing the different technological steps. For example, important work has been conducted on aspects of nanolithography, to achieve networks of nano ribbons of 20 nm width, length 1 m, and spaced 40 nm. The transistors fabricated and characterized during my thesis work having performances at the highest international level
Delaroque, Thomas. "Etude et mise en place d'outils de caractérisation électrique basés sur la technique AFM, en vue de la localisation de défauts au niveau des zones de dopage". Caen, 2010. http://www.theses.fr/2010CAEN2057.
Pełny tekst źródłaThis manuscript is devoted to the study of two electrical modes based on the atomic force microscopy (AFM): the Scanning Capacitance Microscopy (SCM) and the Scanning Spreading Resistance Microscopy (SSRM). After the development of the sample preparation methodology, the effect of measurement parameters on the output signal was characterized during analysis. For each method, experimental results are interpreted taking into account the dimensional and structural specificities of the different samples. This manuscript presents a theoretical analysis based on the fundamentals of these techniques and offers a new approach of the specific tip-sample system behaviour. In SSRM, the theoretical model of a hetero-junction has been verified by measurements. In SCM, the geometric decomposition of the tip has allowed to understand the evolution of signals according to the measurement parameters. These studies highlight the strengths of both methods and their undeniable complementarity in the analysis of specific cases
Trigui, Mounir. "Etude des susceptibilites magnetiques en champ alternatif et continu de carottes de la croute oceanique en vue de l'interpretation des diagraphies electromagnetiques et magnetiques". Paris 6, 1987. http://www.theses.fr/1987PA066652.
Pełny tekst źródłaTrigui, Mounir. "Etude des susceptibilités magnétiques en champ alternatif et continu de carottes de la croûte océanique en vue de l'interprétation des diagraphies électromagnétiques et magnétiques". Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb37610371x.
Pełny tekst źródłaRoelens, Yannick. "Etude et caractérisations microondes en basses températures de résonateurs coplanaires supraconducteurs et de transistors en vue de réaliser des dispositifs micro-électroniques". Lille 1, 2000. http://www.theses.fr/2000LIL10131.
Pełny tekst źródłaScorretti, Riccardo. "Caractérisation numérique et expérimentale du champ magnétique B.F. généré par des systèmes électrotechniques en vue de la modélisation des courants induits dans le corps humain". Phd thesis, Ecole Centrale de Lyon, 2003. http://tel.archives-ouvertes.fr/tel-00140131.
Pełny tekst źródłaBrèque, Cyril. "Développement et mise en oeuvre de méthodes optiques pour la mesure de relief et de champ de déformations en vue de la modélisation d'organes biologiques". Phd thesis, Université de Poitiers, 2002. http://tel.archives-ouvertes.fr/tel-00008546.
Pełny tekst źródłaScorretti, Riccardo Masson Jean-Pierre Daniel. "Caractérisation numérique et expérimentale du champ magnétique B.F. généré par des systèmes électrotechniques en vue de la modélisation des courants induits dans le corps humain". [S.l.] : [s.n.], 2003. http://bibli.ec-lyon.fr/exl-doc/rscorret.pdf.
Pełny tekst źródłaBoutry, Hervé. "Potentialités des hétérostructures GaSb/AlxGa1-xSb/InAs sur substrat GaAs pour la réalisation de HEMT en vue d'applications faible bruit en ondes millimétriques". Lille 1, 2002. https://pepite-depot.univ-lille.fr/RESTREINT/Th_Num/2002/50376-2002-299.pdf.
Pełny tekst źródłaPelletier, Isabelle. "Traitement des données de réservoir en vue d'une simulation numérique de la diagenèse : application à l'ullitisation du Brent dans un champ de la Mer du Nord". Institut de physique du globe (Paris), 1997. http://www.theses.fr/1997GLOB0009.
Pełny tekst źródłaScorretti, Riccardo. "Caractérisation numérique et expérimentale du champ magnétique B. F. Généré par des systèmes électrotechniques en vue de la modélisation des courants induits dans le corps humain". Ecully, Ecole centrale de Lyon, 2003. http://bibli.ec-lyon.fr/exl-doc/rscorret.pdf.
Pełny tekst źródłaThis work is devoted to the developpement of models and numerical tools, to simulate the induced phenomena inside the human body, within the frequency range 50Hz-100KHz. Two main problems have to be solved : find the spatial distribution of a magnetic field generated by a power system (stray fields) ; compute the currents, which are induced by these stray fields inside the human body. Field radiated by a known system : classical numerical methods are not well adapted to this problem (they are too expansive) : we present a 3D model, which takes into account only the "essentials" of the system. Field radiated by an unknown system : we have developed several models of equivalent source, basing upon the concept of multipole. The parameters of these models are fitted from some local measurements of the flux density. Finally, we have developed a special formulation using finite elements, in order to compute the induced current density inside the human body
Rathoin, Sylvie. "Contribution à la caractérisation du rayonnement électromagnétique de la foudre et à sa modélisation en vue du couplage sur les câbles". Phd thesis, Ecole Centrale de Lyon, 1993. http://tel.archives-ouvertes.fr/tel-00377473.
Pełny tekst źródła* Tout d'abord, nous nous sommes attachés à constituer une base de données en réalisant, lors de la campagne de foudre déclenchée de Saint-Privat-d'Allier, des mesures de champ électromagnétique et de courant induit sur une ligne triphasée moyenne tension expérimentale de transport. Cependant, la lourdeur de ce type d'expérimentation nous a amenés à l'étude du phénomène en laboratoire.
* Nous avons donc utilisé ensuite l'analogie partielle qui existe entre la foudre et les grandes étincelles de laboratoire pour définir un moyen d'essais moins contraignant. Il est apparu que les simulations en laboratoire haute tension sont satisfaisantes dans la mesure où elles permettent l'étude de certaines phases de la décharge pratiquement inaccessibles en foudre naturelle ou déclenchée, telles que la propagation du précurseur vers le sol. Cependant, il existe quelques limites à ce type d'expérimentation qu'il ne faut pas négliger et qui rendent complémentaires ces deux moyens de mesures.
* Enfin, nous nous sommes intéressés à l'aspect modélisation du rayonnement de la foudre en recensant les principaux modèles existants et en les testant dans le cadre des champs proches (distance à la décharge inférieure à 500 mètres). Cette étude numérique a permis de préciser les limites de ces modèles et leur sensibilité par rapport à certains paramètres de la décharge ou de la modélisation.
Mate, Sujay. "Développement d'un simulateur du ciel pour les instruments à grand champ de vue X-gamma en orbite terrestre basse : application à l'évaluation des performances du spectro-imageur SVOM-ECLAIRs". Thesis, Toulouse 3, 2021. http://www.theses.fr/2021TOU30031.
Pełny tekst źródłaGamma-Ray Bursts (GRBs) are the most luminous explosions in the universe. They are observed as bright flashes of gamma/X-rays (lasting a few milliseconds to a few tens of seconds) followed by an "afterglow" emission (usually at longer wavelengths). They are produced either due to the merger of two compact objects (a pair of neutron stars or a neutron star and a black hole) or due to the core collapse of a massive star (> 15 solar mass). GRBs are excellent candidates to study physics at extreme energies and densities. They also constitute important astrophysical tools to probe the history of the universe as they are observed at all epochs. The upcoming (June 2022) Sino-French mission SVOM (Space-based multi-band astronomical Variable Objects Monitor) aims to detect and study GRBs using dedicated space and ground based instruments to obtain multi-wavelength coverage. The primary instrument onboard SVOM spacecraft is ECLAIRs, a wide-field (~ 2 sr) coded-mask imager sensitive in the 4 - 150 keV energy range. ECLAIRs will detect and localise GRBs (and other high energy transients) in near real time using an onboard trigger. ECLAIRs will encounter a high and variable background due to the wide field-of-view (FoV) and the pointing strategy of SVOM which makes the Earth transit through the FoV. A new method (called Particle Interaction Recycling Approach or PIRA), based on Monte-Carlo simulations (GEANT4), was developed to estimate the variable background accurately and rapidly. The simulations of the background are complemented with simulations of X-ray sources and gamma-ray bursts to generate complete observation scenarios. The variable background of ECLAIRs poses challenges to detect GRBs and affects the sensitivity of the instrument. We use the simulated data to evaluate the performance of the onboard trigger, in particular, the impact of the variable background and its sensitivity to the GRB characteristics (duration, temporal profile, spectral shape,position in the FoV). ECLAIRs will send all detected photons to the ground. In addition, the availability of a larger computational power and the better knowledge of the context (e.g. background variations, sources in the FoV, etc.) on the ground motivates us to develop an "offline trigger" to overcome the challenges faced by the onboard trigger. An algorithm based on wavelet transforms is proposed to detect GRBs as part of the offline trigger. The work in this thesis, i.e. the development of PIRA, instrument's performance evaluation and development of a trigger method, provides a sound basis to build an effective offline trigger that will complement the onboard trigger and improve the overall performance of the SVOM mission
Nsele, Séraphin Dieudonné. "Analyse électrique et en bruit basse fréquence et haute-fréquence des technologies InAIN/GaN HEMTs en vue de la conception d'amplificateurs robustes faible bruit en bande Ka". Toulouse 3, 2014. http://thesesups.ups-tlse.fr/2501/.
Pełny tekst źródłaThe high bandgap technologies are being increasingly popular for over a decade because of their natural ability to perform electronic functions operating at high power, high temperature and high frequency. Among these technologies, one based on the heterostructure AlGaN / GaN is most mature currently at microwave frequencies. The use of a heterojunction InAlN / GaN is an attractive solution to increase the operation frequency of these devices and thus to realize circuits operating at millimeter waves. The first part of our work is devoted to the study of various InAlN/GaN technology developed by III-V Lab. It helped to highlight the different gate current conduction mechanisms through an analysis of the leakage current and the C-V measurements of the Schottky junction. Measures in small-signal showed the frequency dispersion of the output conductance and the extrinsic transconductance until 1 GHz. We have proposed broadband analytical models to take into account the dispersion phenomena during the circuit design. A second part consisted of the study of the background noise in the InAlN / GaN transistors. The low-frequency noise characterizations and modeling revealed and confirmed trapping / detrapping mechanisms observed in the electrical study. The study of highfrequency noise has assessed the technological developments of this sector and to know the optimal conditions for the design of LNAs. In the last part, hybrid low noise amplifiers have been made from these devices deferred flip-chip on alumina to demonstrate the potential of this technology in Ka-band. Single stage amplifiers have been designed especially for stress testing, and have a gain of 5. 6 dB and a noise figure of 3. 1 dB at 29. 5 GHz. The simulations carried out on 3 stages amplifiers indicate interesting performances in terms of gain (20 dB) and noise figure (3 dB) compared to those obtained in the literature on the GaN based devices
Koubaa, Taoufik. "Métrologie thermique en vue de la régulation d'un four de tirage de monocristaux d'AsGa". Grenoble 1, 1986. http://www.theses.fr/1986GRE10135.
Pełny tekst źródłaSimbelie, Frédérique. "Caractérisation et Modélisation de structures MASMOS en vue de la conception d'un amplificateur de puissance pour la LTE". Thesis, Limoges, 2018. http://www.theses.fr/2018LIMO0010/document.
Pełny tekst źródłaThe main objective of this work is the characterization and modeling of a new component named MASMOS designed and patented by ACCO company. This new structure overcomes the issue concerning the inherent low breakdown voltage of CMOS technology. The first chapter describes the two stacked transistors included in the MASMOS structure and its behavior with respect to the control voltages. Thereafter, the key steps required to develop the non-linear model have been detailed. Finally, the parameters used to characterize the power amplifiers performances are defined as well as the linearity criterion. The second chapter concerns the MASMOS electrical model, done for two different size. Model extraction is explained starting from the mandatory device characterization. Device optimal load impedances are estimated thanks to load-pull simulations. Furthermore, the CAD-compatible models are validated in large signal operation using CW characterizations for several load impedances. Last chapter is dedicated to the MASMOS linearity assessment using two different measurement set up. A generic test signal consisting in 8 non equidistant carriers, allowing non-frequency overlap is used to determine the NPR in-band. Then characterization of the linearity of pre-matched MASMOS was carried out using a 16-QAM modulation and also LTE signals
Mauger, François. "Double ionisation d' atomes soumis à des impulsions laser intenses : vue de l' espace des phases". Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4031.
Pełny tekst źródłaWhen subjected to strong and short laser pulses, atoms may lose electrons. Several ionization channels are involved in such double ionization events, like nonsequential double ionization (NSDI) and its associated recollision scenario. Recollision is now seen as the “keystone of strong field physics”, for its insights into the organization of matter, and is one of the most dramatic manifestations of electron-electron correlation in nature. In this manuscript a theoretical analysis of the double ionization mechanisms is carried out using classical mechanics. This description complements quantum treatments by observing the dynamics from a different framework, with the light of nonlinear dynamics, as both frameworks exhibit the main ingredient, i.e., strong electron-electron correlation. The analysis, carried out in phase space (e.g., through reduced models) enables the identification of the organizing structures that regulate the ionization channels. For linearly polarized lasers, the recollision mechanism is completed by the picture of the “inner” electron. The inner electron gives access to a fine description of the recollision dynamics and explains the routes to double ionization. It also enables verifiable predictions such as the location of the characteristic knee shape in the double ionization yield versus laser intensity and fully explains delayed ionizations like RESI. For circular polarization, it is commonly believed that recollision is not possible, despite apparently contradictory experimental results. In fact, the phase space analysis shows that recollision is possible but not accessible to all atoms, thus reconciling the previous experimental results
Wei, Lumei. "Etude de l'impact des paramètres de protection périphérique et environnementaux de composants de puissance en carbure de silicium en vue de leur montée en tension". Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30354/document.
Pełny tekst źródłaNowadays, most of the semiconductor devices used in power electronics are silicon (Si) based devices. In order to meet the new electrical and thermal constraints induced by the demand in rising both the operating voltage and the power density of the electrical energy converters, the use of wide band gap semiconductors such as silicon carbide (SiC) may represent an adequate solution, thanks to their critical electric field (EC) which is about ten times higher than that of Si and to their ability of operating at temperatures beyond 200 °C. A state-of-the-art on the readily (commercially) available high voltage SiC diodes (10kV or higher) is presented, highlighting the progress made in improving the materials themselves as well as their peripheral protection. However, regarding the die insulating materials, the studies mainly focus on the primary passivation step, which was often mentioned as the most critical one. Obviously much less work is carried out on the impact of the secondary passivation and encapsulation materials. The goal of this study is to contribute to a better knowledge of the mechanisms involved in the SiC chips and electrically insulating environment breakdown while in a blocking state, as well as to the identification of the most relevant parameters acting on these phenomena. Thus, a study of the correlated properties of the semiconductor and the passivation and encapsulation materials present on the surface of the chip was carried out on SiC-4H bipolar diodes protected by junction termination extension (JTE), supplied by IBS society, within the framework of the 'FilSiC' research project. First, a numerical simulation study of the entire structure (SiC and insulating materials) was carried out using the Sentaurus Device software (Synopsys). This allowed for quantifying the electric field stresses throughout the structure for a given applied voltage as well as their dependence on the properties of the considered insulating materials. This study was equally used for choosing the appropriate parameters of the epitaxial substrate and for designing the lateral and the surface geometry of the diodes (the technological parameters being fixed elsewhere), in view of the subsequent experimental study of their breakdown voltage in the 1kV-6kV range. Concurrently, the electrical characterization of the primary passivation material used (thick silicon dioxide layer) was performed by using MIS (metal-insulator-semiconductor) type structures, in a temperature range of up to 300 °C. This allowed to determine its main electrical properties, particularly the dielectric breakdown voltage. The work then focused on the room-temperature characterization of the breakdown voltage of the full structures built around the different manufactured diodes. The tests were carried out both under high vacuum conditions and under nitrogen at atmospheric pressure. The behavior of the different study cases observed under vacuum conditions during the breakdown, coupled with the simulation results, allowed to determine the values of the maximum electric fields induced in the different insulating materials and to correlate them to their known dielectric breakdown values. On the other hand, additional results obtained under nitrogen atmosphere confirmed some technological parameters and mechanisms at play during the breakdown of the diodes. Several guidelines for the optimization of these technological parameters (epitaxy and JTE) and of the insulating passivation and encapsulation layers (thickness, permittivity) of the "high voltage" SiC diode were derived from this study