Дисертації з теми "Polarisation control"
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Maguire, Sean Thomas George. "Attitude determination using low frequency radio polarisation measurements." Thesis, University of Cambridge, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708927.
Повний текст джерелаWalwyn-Brown, Katherine. "Control of Th2 polarisation by dendritic cells and natural killer cells." Thesis, University of Manchester, 2018. https://www.research.manchester.ac.uk/portal/en/theses/control-of-th2-polarisation-by-dendritic-cells-and-natural-killer-cells(fd15f834-f926-40f1-88ff-217bf1fbf263).html.
Повний текст джерелаHonda, S., H. Itoh, J. Inoue, H. Kurebayashi, T. Trypiniotis, C. H. W. Barnes, A. Hirohata, and J. A. C. Bland. "Spin polarization control through resonant states in an Fe/GaAs Schottky barrier." American Physical Society, 2008. http://hdl.handle.net/2237/11246.
Повний текст джерелаRendón, Barraza Carolina. "Polarization-resolved nonlinear microscopy in metallic and ferroelectric nanostructures for imaging and control in complex media." Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4365.
Повний текст джерелаIn this work, we develop a novel polarized nonlinear microscopy method that exploits sub-diffraction resolution information. Fourier analysis of the polarization modulated nonlinear signal is performed on over-sampled, drift-corrected images (50nm pixel size). The information gained by polarization-induced modulation signals provides a higher level of spatial selectivity that is directly related to the local optical response of the investigated system, at a scale below the diffraction limit. The gain in spatial scale is due to the additional spatial sensitivity brought by polarization. This approach is applied to polarized second harmonic generation imaging in plasmonic nanostructures (150nm size) of multi-branched shapes, in which the vectorial nature of the local field confinement can be retrieved with a resolution of 40 nm. We also demonstrate the possibility to image spatial heterogeneities within crystalline ferroelectric BaTiO3 nanoparticles of 70nm to 500nm size, emphasizing in particular the existence of a centrosymmetric shell in small size structures. These nanostructures will be used as starting models for coherent optical probes in biological media (cells, tissue slices or in vivo) with two objectives. First, the nonlinear nature of their emission will make them stable and tunable nanosources, able to report their localization with high accuracy in 3D, potentially sensing local environment changes, and actively inducing perturbations such as controlled temperature increase at the nanoscale. Second, the coherent nature of their emission will make them useful as local nanoprobes for wavefront and polarization correction through scattering media
Rolloff, Otto. "Polarisation de substrat à partir de micro-générateurs distribués pour une gestion de l’énergie pilotée par l’activité dans les technologies FD-SOI." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAT081.
Повний текст джерелаWith the exponential growth of the embedded systems and the so-called IoT objects, the need of reducing power consumption for environmental and economic considerations requires better power-saving techniques without compromising circuit performances. However, CMOS transistors are achieving their physical limits in terms of scaling and the opportunities to enhance the integrated circuit will be more on the design side than on the technology side. Thereto, it is noticeable that complex digital circuits spent a significant amount of energy during idle periods and tend to activate much more blocks than needed. This drawback results from the usage of the synchronous paradigm. Asynchronous circuits provide intrinsic and local signals that mitigate the unnecessary block activation in circuits and offers an intrinsic idle mode. Moreover, these signals are usable to locally manage body-bias voltages in Fully Depleted Silicon On Insulator (FD-SOI) in order to save power. This thesis proposes a design strategy dedicated to asynchronous circuits exploiting the body-biasing facilities of the FD-SOI technology. Firstly, an analysis of the FD-SOI technology has been made in order to analyze the new degrees of freedom offered to the designers by mainly controlling the transistor threshold voltage (Vth) thanks to body-biasing effect. This latter is indeed able to change the transistor speed and power consumption. Secondly, a body-biasing standard cell based on a level shifter architecture has been designed in order to locally adapt the body-biasing voltage. Thirdly, we proposed a distributed activity-driven strategy easily managing a large number of Body-Biasing Domains (BBDs). Lastly, the aforementioned techniques have been implemented and tested in a chip designed in 28 nm FD-SOI technology from STMicroelectronics
Wei, Zhaopeng. "Auto-polarisation de la grille arrière pour auto-calibration de cellules analogiques et mixtes en technologie UTBB-FDSOI." Thesis, Université Côte d'Azur (ComUE), 2019. http://www.theses.fr/2019AZUR4033.
Повний текст джерелаIn the competition of the miniaturization of integrated electronic circuits, UTBB-FDSOI technologies are better adapted to nanometric sizes, because they can limit the problems due to the random doping variations used in conventional “bulk” transistors and bring a significant improvement in terms of performance and low power design. This thesis is a contribution to the development of novel building blocks for PLL using complementary logic in 28nm UTBB-FDSOI technology. Using this technology, we proposed a complementary inverter based on a pair of back-gate cross-coupled inverters offering a fully symmetrical operation of complementary signals. This design concept can be extended to any digital cells to generate more stable, symmetrical and resilient output signals. First, we designed a fast and efficient ring oscillator composed by four complementary inverters delivering quadrature clocks which oscillation frequency is 7.3GHz. Then using complementary logic and back-gate control structure, we proposed an efficient solution to produce novel structures of VRCO, PFD, Charge pump, divisor etc., which are the key building blocks of high-speed low noise PLLs. All these designs have been simulated and verified using Cadence. Moreover, a test chip of RO, current mirror and VCRO have already been realized in silicon and tested
Gao, Jing. "Etude et mise au point d'un capteur de gaz pour la detection sélective de NOx en pot d'échappement automobile." Phd thesis, Ecole Nationale Supérieure des Mines de Saint-Etienne, 2011. http://tel.archives-ouvertes.fr/tel-01016361.
Повний текст джерелаBettahar, Houari. "High accurate 3-D photo-robotic nano-positioning for hybrid integrated optics." Thesis, Bourgogne Franche-Comté, 2019. http://www.theses.fr/2019UBFCD019/document.
Повний текст джерелаThe hybrid integration of individual photonic elements appears as promising, because it may provide high performances, propose new optical functionalities and products and exploit new propagation modes of light beams. This approach requires an accurate multi Degree-Of-Freedom (DOF) positioning of the individual photonic elements. Hence, the inaccurate multi-DOF measurement and robots control are the main locks to overcome, notably at the micro-scale. For this sake, an original photo-robotic approach has been proposed, relying on multi-DOF robot motion associated with the use of 1-D Fabry-Perot interferometry measure to realize multi-DOF pose measure. This approach notably integrates the issue of 6-DOF robot calibration that has been studied through extrinsic and/or intrinsic geometric parameters calibration. In order to find the appropriate calibration strategy for high positioning accuracy and adapted to the context of micro-positioning of optical components, a quantification and durability analysis of optical and robotic performances have been investigated. Experimental investigations demonstrate that a rotational and translational positioning accuracy of 0.004° and 27.6 nm have been obtained respectively.This photo-robotic approach has especially been applied to achieve the 6-DOF positioning of an optical lamella relative to an optical fiber with high accuracy that also conduct to maximum optical performances. The approach has also been applied to control the optical polarization states at the output of an hybrid optical system through achieving high accurate rotations of a specific optical wave plate around the optical axis. The experimental results notably demonstrate that the high positioning accuracy enables to accurately control of the optical polarization state
Cao, Shuiyan. "Using plasmonic nanostructures to control electrically excited light emission." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS042/document.
Повний текст джерелаIn this thesis, we use different plasmonic nanostructures to control the emission of electrically-excited light. Our electrical emission is from an “STM-nanosource” which uses the inelastic tunnel current between the tip of a scanning tunneling microscope (STM) and a metallic sample, to locally excite both localized and propagating surface plasmon polaritons. The interaction of our STM-nanosource and a circular plasmonic lens (a series of concentric slits etched in a thick gold film) produces a radially polarized microsource of low angular spread (≈±4°). The influence of the structural parameters on the angular spread of the resulting microsource is also investigated. In addition, a low angular spread (<±7°) for a large wavelength range (650-850 nm) is achieved. Thus this electrically-driven microsource of nearly collimated light has a broad spectral response and is optimal over a wide energy range, especially in comparison with other resonant plasmonic structures such as Yagi-Uda nanoantennas. The interaction of our STM-nanosource and an elliptical plasmonic lens (a single elliptical slit etched in a thick gold film) is also studied. When the STM excitation is located at the focal point position of the elliptical plasmonic lens, a directional light beam of low angular spread is acquired. Moreover, in the experiment we find that by changing the eccentricity of the elliptical plasmonic lens, the emission angle is varied. It is found that the larger the eccentricity of the elliptical lens, the higher the emission angle. This study provides a better understanding of how plasmonic nanostructures shape the emission of light. The interaction of STM-excited SPPs and a planar plasmonic multi-layer stack structure is also investigated. It is demonstrated that using STM excitation we can probe the optical band structure of the Au-SiO₂-Au stack. We find that the thickness of the dielectric plays an important role in changing the coupling between the modes. We also compare the results obtained by both laser and STM excitation of the same stack structure. The results indicate that the STM technique is superior in sensitivity. These findings highlight the potential of the STM as a sensitive optical nanoscopic technique to probe the optical bands of plasmonic nanostructures. Finally, the interaction of an STM-nanosource and an individual triangular plate is also studied. We find that when the STM excitation is centered on the triangular plate, there is no directional light emission. However, when the STM-nanosource is located on the edge of the triangle, directional light emission is obtained. This study provides us a novel avenue to achieve directional light emission. We also study probing the optical LDOS of the triangle with the STM-nanosource. Thus, our results show that the manipulation of light is achieved through SPP-matter interactions. Using plasmonic nanostructures, we control the collimation, polarization, and direction of the light originating from the STM-nanosource
Makdissy, Tony. "Nouvelles topologies de cellules déphaseuses à coût et complexité réduits pour les antennes réseaux réflecteurs large bande." Phd thesis, INSA de Rennes, 2013. http://tel.archives-ouvertes.fr/tel-00958105.
Повний текст джерелаPolge, David. "Amplificateur de puissance à polarisation contrôlée et à faible variation du temps de propagation de groupe pour systèmes de localisation en technologie ultra large bande impulsionnelle." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0206/document.
Повний текст джерелаThe use of impulse radio (IR) ultra-wideband (UWB) technology for indoor localization systems both improves signal accuracy and reduces disturbances from multipath. A new standard for emergency situations requires the design of a higher output power UWB power amplifier (PA) as the usual maximum output power has been raised by 20 dB in order to allow the signal to pass through thick obstacles, thus helping rescue operations. First, a UWB PA state of the art is presented, and the design of both a power cell and a driver cell are detailed, to achieve the required output power level and additional gain, respectively. Finally, a bias controlled amplification system is described, taking advantage of the IR profile of the UWB signal. The PA is activated only for pulse occurrences, reducing drastically its power consumption
Wang, Mengjia. "Spin-orbit interactions for steering Bloch surface waves with the optical magnetic field and for locally controlling light polarization by swirling surface plasmons." Thesis, Bourgogne Franche-Comté, 2019. http://www.theses.fr/2019UBFCD013/document.
Повний текст джерелаMy thesis is devoted to novel nano-optical phenomena and devices based on spin-orbit interaction (SOI) of light. First, magnetic spin-locking, i.e., an SOI solely driven by the magnetic field of light, is demonstrated with Bloch surface waves. It provides a new manifestation of the magnetic light field. Then, we propose and demonstrate the concept of traveling-wave plasmonic helical antenna (TW-HPA), consisting of a narrow helical gold-coated wire non-radiatively fed with a dipolar nano-antenna. By swirling surface plasmons, the TW-HPA combines subwavelength illumination and polarization transformation. The TW-HPA is demonstrated to radiate on the subwavelength scale almost perfectly circularly polarized optical waves upon illumination with linearly polarized light. With this subwavelength plasmonic antenna, we developed strongly integrated arrays of point-light emissions of opposite handedness and tunable intensities. Finally, by coupling two couples of TW-HPAs of opposite handedness, we obtained new polarization properties so far unattainable
Fusaro, Adrien. "Auto-organisation d’ondes optiques incohérentes : Condensation, thermalisation et repolarisation." Thesis, Bourgogne Franche-Comté, 2019. http://www.theses.fr/2019UBFCK035/document.
Повний текст джерелаThe subject of this thesis concerns the study of phenomena of self-organization of incoherentoptical waves. This work is essentially theoretical and numerical and relies on different formalisms of waveturbulence theory, the Hamiltonian singularities, and different experiments.The first part of the thesis deals with the irreversible processes of thermalization and condensation ofincoherent waves. The phenomenon of condensation is characterized by the formation of a large scale co-herent structure (condensate) that remains immersed in a sea of small scale fluctuations (uncondensedparticules). In spite of the large propagation lengths required to reach the condensed equilibrium state, wehave identified theoretically and experimentally in atomic vapors a phenomenon of pre-condensation thatoccurs far from thermal equilibrium and that plays the role of a precursor for the asymptotic equilibriumstate. On the other hand, on the basis of recent experimental observations of the effect of beam self-cleaningin multimode optical fibers, we have developed a kinetic wave turbulence approach that accounts for theimpact of a structural disorder of the material. The theory reveals that disorder leads to a significant ac-celeration of the condensation process, which can explain the beam self-cleaning effect. Our experimentsreport the observation of the transition from the thermal distribution toward condensation with a macro-scopic fraction of condensed power into the fundamental mode. We have studied the impact of a highlynonlocal (or non-instantaneous) response on the nonlinear propagation of a speckle beam, which allowedus to identify a mechanism of spontaneous emergence of long-range phase coherence.The second part of the manuscript is based on a phenomenon of polarization attraction when two in-coherent waves are injected at both ends of an optical fiber. The spatio-temporal dynamics of the counter-propagating partially polarized waves relax toward a quasi-stationary state characterized by a phenomenonof self-polarization that occurs just in the middle point of the optical fiber. This effect is related to the pre-sence of singularities in the Hamiltonian system associated to the stationary state
Assemat, Élie. "Sur le rôle des singularités hamiltonniennes dans les systèmes contrôlés : applications en mécanique quantique et en optique non linéaire." Phd thesis, Université de Bourgogne, 2012. http://tel.archives-ouvertes.fr/tel-00833905.
Повний текст джерелаSoussan, Dimitri. "Contributions aux interfaces d'entrées / sorties rapides en technologies Silicium-Sur-Isolant partiellement et totalement désertées." Phd thesis, Université de Grenoble, 2013. http://tel.archives-ouvertes.fr/tel-00935123.
Повний текст джерелаFrazer, Gordon Lee. "How TCR signal strength controls CTL polarisation for target killing." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/277687.
Повний текст джерелаKechiche, Mohamed Bouraoui. "Etude et développement de capteurs / effecteurs filamentaires de faibles diamètres intégrables dans des structures textiles." Phd thesis, Université de Haute Alsace - Mulhouse, 2012. http://tel.archives-ouvertes.fr/tel-00844135.
Повний текст джерелаProst, Emilien. "Optique ultra-rapide dans des rotors moléculaires synchrones." Thesis, Bourgogne Franche-Comté, 2020. http://www.theses.fr/2020UBFCK009.
Повний текст джерелаThis thesis reports on the study of unidirectional rotation of molecules and focuses on the rotational Doppler effect occuring in the course of third-harmonic generation in coherently spinning molecules.The rotational Doppler effect appears when a circularly polarized wave interacts with an anisotropic rotating object. During the interaction, an exchange of angular momentum and energy between the field and the object occurs, leading to a frequency shift of the wave. In this work, the frequency shift of the third-harmonic generated in unidirectionaly rotating molecules has been observed. An anlytical model developped in the mansucript forsees four kinds of frequency shifts depending on the mutual handedness of the circular polarization of the fundamental and harmonic fields and the handedness of the rotating molecules. The four shifts have been measured in third-harmonic generation in unidirectionaly rotating molecules of O2, N2, and CO2. A thorough study of the rotational Doppler effect and the underlying physics has been conducted. A polarization analysis of the third-harmonic produced in coherently spinning molecules has also been done, showing the high degree of ellipticty of the harmonic. From this polarization analysis, the orientation of the molecular axis can be retrieved, providing a new way to measure the angular frequency of rotating molecules
Jaron, Barbara. "Etude des mécanismes impliqués dans la régulation des réponses Th1/Th17 néonatales : vers l'identification d'adjuvants adaptés à la vaccination pédiatrique ?" Paris 6, 2010. http://www.theses.fr/2010PA066051.
Повний текст джерелаApostoluk, Aleksandra. "Dynamique de la polarisation tout-optique de molécules organiques présentant un photochromisme rapide en phase polymérisée." Phd thesis, Université d'Angers, 2003. http://tel.archives-ouvertes.fr/tel-00110790.
Повний текст джерелаAmary, Pascal. "Developpement, optimisation et industrialisation d'un instrument de controle, en temps reel et in-situ, des procedes de depot et de gravure en micro-electronique : un ellipsometre a modulation de polarisation." Orléans, 1991. http://www.theses.fr/1991ORLE2004.
Повний текст джерелаMunch, Guillaume. "Syntaxe et modèles d'une composition non-associative des programmes et des preuves." Paris 7, 2013. http://www.theses.fr/2013PA077130.
Повний текст джерелаThe thesis is a contribution to the understanding of the nature, role, and mechanisms of polarisation in programming languages, proof theory and categorical models. Polarisation corresponds to the idea that we can relax the associativity of composition, as we show by relating duploids, our direct model of polarisation, to adjunctions. As a consequence, polarisation underlies many models of computation, which we further show by decomposing continuation-passing-style models of delimited control in three fondamental steps which allowing us to reconstruct four call-by-name variants of the shift and reset operators. It also explains constructiveness-related phenomena in proof theory, which we illustrate by providing a formulae-as-types interpretation for polarisation in general and for an involutive negation in particular. The cornerstone of our approach is an interactive term-based représentation of proofs and programs (L calculi) which exposes the structure of polarities. It is based on the correspondence between abstract machines and sequent calculi, and it aims at synthesising various trends: the modelling of control, evaluation order and effects in programming languages, the quest for a relationship between categorical duality and continuations, and the interactive notion of construction in proof theory. We give a gentle introduction to our approach which only assumes elementary knowledge of simply-typed lambda calculus and rewriting
Saito, Kazuko. "Analyse quantitative par RMN de l'état solide C-13 par polarisation croisée et en rotation à l'angle magique "CPMAS" de formulations galéniques en vue de l'identification de contrefaçons." Versailles-St Quentin en Yvelines, 2011. http://www.theses.fr/2011VERS0003.
Повний текст джерелаThis thesis undertakes a reinvestigation of the solid state NMR CPMAS measurement for pharmaceutical materials, in order to assess their quality: original drugs, generics of counterfeits. The pulse sequence RAMP-CPMAS was revisited in order to evaluate its performances for quantification. Combining RAMP-CPMAS with a forced return to equilibrium with a “flip-back” pulse allows obtaining a measurement in a reasonable and constant time, suppressing one of the limitations for the implementation of solid state NMR in the industry. All the parameters of the magetization transfert du ring CPMAS can therefore be under experimental control, including those described to be intrinsically sample dependent, , TCH et T1, by using a good choice of experimental parameters. Therefore, CPMAS measurement can be made quantitative. Base upon these results, recommandations for quantitative measurements are suggested for different types of situations
Assemat, Elie. "Sur le rôle des singularités hamiltoniennes dans les systèmes contrôlés : applications en mécanique quantique et en optique non-linéaire." Phd thesis, Université de Bourgogne, 2012. http://tel.archives-ouvertes.fr/tel-00804765.
Повний текст джерелаTehini, Ronald. "Vers le contrôle de l'alignement et de l'orientation : théorie et expérience." Phd thesis, Université de Bourgogne, 2010. http://tel.archives-ouvertes.fr/tel-00639366.
Повний текст джерелаLaurent, Sabine. "Orientation optique et relaxation du spin du trion dans les boîtes quantiques d'InAs/GaAs." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2004. http://tel.archives-ouvertes.fr/tel-00007028.
Повний текст джерелаJohansen, Jonathan Frederick. "Mathematical modelling of primary alkaline batteries." Thesis, Queensland University of Technology, 2007. https://eprints.qut.edu.au/16412/1/Jonathan_Johansen_Thesis.pdf.
Повний текст джерелаJohansen, Jonathan Frederick. "Mathematical modelling of primary alkaline batteries." Queensland University of Technology, 2007. http://eprints.qut.edu.au/16412/.
Повний текст джерелаVervisch-Fortuné, Isabelle. "Sensibilité de la technique d'émission acoustique à la corrosion des armatures dans le béton." Toulouse 3, 2009. http://thesesups.ups-tlse.fr/666/.
Повний текст джерелаCorrosion of reinforcement is a major cause of concrete deterioration. The two most common mechanisms contributing to the development of corrosion are penetration of chlorides and carbonation of cover concrete. These two mechanisms induce two types of corrosion, pitting and generalised corrosion. One of the non destructive techniques used in Civil Engineering, acoustic emission, extends to monitor the corrosion of prestressing cables and metal structures. The objective of this thesis is firstly to define an accelerated corrosion test able to provide conditions close to natural corrosion and secondly to check the sensitivity of acoustic emission for detecting the effect of early corrosion in reinforced concrete. Usual electrochemical methods are used to validate the results obtained by acoustic emission. These methods, potential of corrosion measure and corrosion rate measurement being RILEM recommendations, remain intrusive methods requiring access to the rebar. From a literature review, various tests were studied, first using high impressed corrosion currents and then by decreasing gradually the current to values existing in structures. Different conditions for initiating corrosion, as an attack by chlorides and carbonation of cover concrete, were also tested. This enables the development of an accelerated corrosion test with densities of corrosion current close to the natural ones. It's about creating a macro-cell by connecting both two rebars in the same concrete, one of the rebar being depassivated by carbonation of concrete, the second remaining in a passive state. Different galvanic currents are obtained with different anodic and cathodic surfaces and distances between electrodes. .
Munch-Maccagnoni, Guillaume. "Syntaxe et modèles d'une composition non-associative des programmes et des preuves." Phd thesis, Université Paris-Diderot - Paris VII, 2013. http://tel.archives-ouvertes.fr/tel-00918642.
Повний текст джерелаMary, Benjamin. "Développement de l'imagerie des systèmes racinaires dans les ouvrages hydrauliques en remblai par tomographie électrique et acoustique." Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4386/document.
Повний текст джерелаWoody vegetation from earth dikes or dams is a fragility factor which can promote mechanisms of degradation such as erosion. An accurate assessment of root system structure, from geophysical non-destructive methods, of root position into the embankment (depth, extension), and a good knowledge of soil conditions are critical in order to anticipate the consequences of vegetation development for the hydraulic structure’s safety. Laboratory experiments allowed determining intrinsic acoustical and electrical root properties leading to identify relevant signatures and discriminate anomalies related to roots in the field. The establishment of adapted experimental devices led us progressively to assess different parameters (roots mass, water content. . . ) under controlled conditions. Experiments in semi-controlled conditions with trees planted into a homogenous soil, were conducted to assess the relevance of different methodologies, such as the use of temporal induced polarization in complex resistivity tomography or the geometry of sensors for acoustical tomography. Innovative data processing such as wavelet analysis were used to valorize the rich database. The results were validated by the determination of actual root position.Finally, field investigations into an embankment have been performed to highlight a spatial variability of dike structures associated with trees presence. A methodology adapted to the geophysical diagnostic of vegetation roots in embankments was developed
Zorni, Chiara. "Contrôle non destructif par courants de Foucault de milieux ferromagnétiques : De l'expérience au modèle d'interaction." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00681790.
Повний текст джерелаZorni, Chiara. "Contrôle non destructif par courants de Foucault de milieux ferromagnétiques : de l’expérience au modèle d’interaction." Thesis, Paris 11, 2012. http://www.theses.fr/2012PA112031/document.
Повний текст джерелаThe aim of this work is the eddy-current testing (ECT) of ferromagnetic materials within magnetic sensors, such as Giant Magneto-Resistances (GMR). Two complementary aspects have been studied. Experimental measurements have been carried out in order to quantify and minimize the noise coming from the materials structure and residual magnetization. On the other hand, a model has been developed in order to be able to simulate the electromagnetic interactions between a ferromagnetic specimen and the EC probe. The GMR sensors are characterized by high sensitivity at low frequency, large dynamic range and are relatively easy to implement. The studies carried out during this thesis allowed us to identify and analyse the “ghost signals” due to magnetic materials. In order to minimize the noise coming from the materials structure, a linear multi-frequencies combination of experimental signals has been employed successfully and the detection of buried flaws has been improved. The residual magnetization in ferromagnetic materials has been experimentally analyzed and an electronic system has been realized to fix the polarisation point of the sensor in the linear response zone of the GMR. Thus, disturbances caused by residual magnetization are successfully reduced. Beside, in order to develop simulation tools aiming at improving the understanding of experimental signals and optimizing the performances of ECT procedures, a model has been developed to simulate the ECT of planar, stratified and ferromagnetic materials affected with multiple flaws. CEA developed for many years semi-analytical models embedded into the simulation platform CIVA dedicated to non-destructive testing. Following a previous work carried out at the laboratory and already integrated in the simulation platform CIVA, developed at CEA-LIST, the new model extends CIVA functionalities to the ferromagnetic planar case. Simulation results are obtained through the application of the Volume Integral Method (VIM) which involves the dyadic Green’s functions. Two coupled integral equations have to be solved and the numerical resolution of the system is carried out using the classical Galerkin variant of the Method of Moments (MoM). Finally, the probe response is calculated by application of the Lorentz reciprocity theorem. A collaboration with the University of Cassino (Italy) and Laboratoire de Génie Electrique de Paris (France) allowed us to compare the three models on experimental and numerical results from literature. Results showed a good agreement between the three models and the model stability has been analyzed
Ulusoy, Inan. "Etude volcano-structurale du volcan Nemrut (Anatolie de l'Est, Turquie) et risques naturels associés." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2008. http://tel.archives-ouvertes.fr/tel-00730602.
Повний текст джерелаRigoudy, Charles. "Couches minces diélectriques avec des inclusions de nanoparticules d'argent réalisées par voie plasma conçues pour le contrôle du gradient de charges électriques sous irradiation électronique pour des applications spatiales." Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30268.
Повний текст джерелаElectron emission phenomenon is intensively studied in many fundamental areas in physics and lays down the principle of operation of a large number of devices such as field emission display devices, Hall thrusters, etc. It is better described for metals. However, when originating from insulating materials it becomes a critical phenomenon involved in reliability issues of components in space applications where surface flashover phenomena and vacuum breakdown are entirely controlled by the electron emission from solids. Depending on the energy of impinging electrons and the dielectric properties, the electrons can be trapped within the dielectric bulk, and/or be responsible of electron emission phenomena. This PhD work, carried out at the interface of three research domains: plasma deposition of thin nanocomposite layers, dielectric charging and charge transport in thin dielectrics, and characterization of materials under irradiation in space environment, aims to explore the effect of metal inclusions (silver nanoparticles, AgNPs), embedded in thin dielectric silica layers, on the physical mechanisms (charge injection, trapping, transport and secondary electron emission from the surface) responsible of the dielectric charging and electron emission from dielectrics, in order to modulate them. Nanostructured thin dielectric silica layers containing a single plan of AgNPs have been elaborated by plasma process successfully combining in the same reactor sputtering of a metallic target and plasma enhanced chemical vapor deposition (PECVD). Structural characterization of the resulting samples has been performed to determine the chemical composition of the plasma silica matrix as well as to obtain the AgNPs size, shape, density and distribution and the total thickness of the structure. These analyses allowed correlation of the structural parameters with the response of the obtained nanostructured dielectric layers under electrical stress and electronic irradiation. It was found that for low energy of the incident electrons (< 2keV) the total electron emission yield (TEEY) from thin silica layers without AgNPs presents an atypical shape with local minimum situated at around 1keV. To get closer to the description of this behavior a model for the TEEY was developed. It is based on Dionne's model, but adapted to dielectrics. It considers the internal electric field resulting from dielectric charging phenomenon.[...]
Lee, Wendy Suk Ling. "Terahertz metasurfaces for wideband polarisation control." Thesis, 2018. http://hdl.handle.net/2440/114267.
Повний текст джерелаThesis (Ph.D.) -- University of Adelaide, School of Electrical and Electronic Engineering, 2018
You, Xiaolong. "Broadband Terahertz Metasurfaces." Thesis, 2021. https://hdl.handle.net/2440/132632.
Повний текст джерелаThesis (Ph.D.) -- University of Adelaide, School of Electrical and Electronic Engineering, 2021
McAfee, David Michael. "Operating Regimes and Automated Control of Holmium and Thulium Non-linear Polarisation Rotation Mode-locked Fibre Optic Lasers." Thesis, 2020. https://hdl.handle.net/2440/136315.
Повний текст джерелаThesis (M.Phil) -- University of Adelaide, School of Physical Sciences : Physics, 2020