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Auswahl der wissenschaftlichen Literatur zum Thema „Mesure d’impédance“
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Zeitschriftenartikel zum Thema "Mesure d’impédance"
Dupertuis, Y. M., A. Gomes Pereira, V. L. Karsegard, L. Genton Graf und T. H. Collet. „Influence des électrodes sur la mesure de la composition corporelle par analyse d’impédance bioélectrique en position couchée“. Nutrition Clinique et Métabolisme 37, Nr. 2 (Mai 2023): e34. http://dx.doi.org/10.1016/j.nupar.2023.03.058.
Der volle Inhalt der QuelleAlonzo, V., F. Berthier, JP Diard und V. Seignole. „Mesure de la pulsation propre de Hopf par spectroscopie d’impédance électrochlmique : application à la dissolution transpassive du nickel“. Journal de Chimie Physique 94 (1997): 1763–78. http://dx.doi.org/10.1051/jcp/1997941763.
Der volle Inhalt der QuelleZIADÉ, F., A. MORILHAT, A. BOUNOUH, A. POLETAEFF, C. SERRANO und D. ALLAL. „Traçabilité des mesures d’impédance électrique entre 100 kHz et 10 MHz“. Revue française de métrologie, Nr. 30 (21.02.2013): 3–11. http://dx.doi.org/10.1051/rfm/2012005.
Der volle Inhalt der QuelleZoghbi, André EL, Lorena Klein und Isabelle Frateur. „Évaluation de la résistance à la corrosion des fils orthodontiques par mesures électrochimiques et microscopie électronique à balayage (MEB)“. L'Orthodontie Française 84, Nr. 4 (27.11.2013): 367–81. http://dx.doi.org/10.1051/orthodfr/2013063.
Der volle Inhalt der QuelleDiard, JP, B. Le Gorrec und C. Montella. „Réexamen des conditions de validité des mesures d’impédance d’un système redox. I. Transfert électronique réversible“. Journal de Chimie Physique 89 (1992): 2153–67. http://dx.doi.org/10.1051/jcp/1992892153.
Der volle Inhalt der QuelleGABRIELLI, Claude. „Méthodes électrochimiques - Mesures d’impédances“. Corrosion Vieillissement, April 1994. http://dx.doi.org/10.51257/a-v1-p2210.
Der volle Inhalt der QuelleNorrenberg, Michelle, und Olivier Lheureux. „La tomographie par impédance électrique : un outil précieux pour le clinicien“. Médecine Intensive Réanimation, 12.08.2020. http://dx.doi.org/10.37051/mir-00023.
Der volle Inhalt der QuelleDissertationen zum Thema "Mesure d’impédance"
Zorgnotti, Valentin. „Mesure d’impédance acoustique pour la caractérisation des cycles limites de moteurs thermoacoustiques“. Thesis, Le Mans, 2019. http://www.theses.fr/2019LEMA1005/document.
Der volle Inhalt der QuelleThis manuscript deals with the experimental characterization of the acoustic limit cycle reached by self-sustained oscillations generated in thermoacoustic engines.A specially designed, high amplitude, acoustic impedance sensor was developed to perform measurements of the input impedance of a thermoacoustic core, as a function of the heating power supplied to the device, of the frequency, and of the amplitude of acoustic forcing.Those measurements can then be used to predict the spontaneous generation of acoustic oscillations and their saturation up to a certain steady-state.Those predictions were successful for various acoustic loads connected to the thermoacoustic core.Moreover, the measurements of acoustic impedance as a function of the amplitude of acoustic oscillations are compared to a model based on the linear thermoacoustic theory, and this comparaison provides insights into the processes controlling the saturation of acoustic oscillations.The experimental procedure described in this manuscript also leads to a pratical way of optimizing the coupling between the thermoacoustic core and the load, in the way that the potential efficiency of thermoacoustic energy conversion is maximized.Finally, an experimental method is described and allows to study the stability of limit cycles, i.e. the temporal evolution of the self-oscillation amplitude, in the case of a system that is able to give rise to a spontaneous periodic \textit{trigg and stop} behavior
Ndiaye, Elhadji Barra. „Contrôle santé de structures sandwichs composites, caractérisation et évaluation non destructives de l’adhésion et du vieillissement : simulations par éléments finis et expérimentation par mesure d’impédance et par ultrasons multiéléments“. Thesis, Le Havre, 2014. http://www.theses.fr/2014LEHA0007/document.
Der volle Inhalt der QuelleThis thesis focuses on the ultrasonic non-destructive testing and evaluation (NDT&E) of composite materials contributing in part to the concept of structural health monitoring (SHM). Specifically, adhesion phenomena and aging of composite sandwich core honeycomb structures are of crucial interest for aeronautics. The properties related to these two phenomena were studied using theoretical models, numerical simulations and experimental results. Based on previous works, using Lamb waves allow to characterize adhesion and aging. Additional simulations were carried out with the finite element software Comsol Multiphysics©. Adhesion defects such as delamination or debonding at the interfaces have been detected and located by means of the Short Term Fourier Transform (STFT) by sliding window, both numerically and experimentally. In view of NDT industrial rates, phased array transducers allow inspection and characterization of local bonding. By comparison, the Debye series method (DSM) was conducted locally to solve the inverse problem of a cut plane of a honeycomb composite. First, sandwich structure aging was investigated using Lamb waves in the air. Second, the aging was evaluated by measuring the electromechanical impedance of a transducer in contact with the samples. These experimental results show that the resonance frequencies and widths variations depend on the degree of porosity, indicating the sensitivity of these methods to the aging
Cassiède, Marc. „Développement d’une technique de microbalance à cristal de quartz pour la mesure de propriétés thermophysiques de fluides sous pression“. Pau, 2010. http://www.theses.fr/2010PAUU3022.
Der volle Inhalt der QuelleThe topic of this thesis is the development of a quartz crystal microbalance technique under pressure in order to study the phase and rheological behaviour of complex viscoelastic systems, and particularly extra-heavy oils. After the validation of the experimental device by measuring phase transition temperatures of waxy model systems, we turned to the study of viscoelastic systems by means of impedance analysis. For this purpose, we have integrated a network analyzer which allows to determine both resonance frequency and dissipation, as well as the comparison of these parameters on several harmonics. These parameters give access to the acoustic impedance of the resonant system and then the material properties (mass and shear modulus) can be deduced. The first results showed an important deviation from theoretical behaviour on the first overtones and particularly on the fundamental mode. Thus, a deep study of the electrical behaviour of AT-cut quartz resonators has been carried out to understand the deviations obtained on the fundamental harmonic mode. Then, we have characterized in detail the effect of pressure on the electrical impedance of these quartz sensors. Finally, we have shown that the phenomena of roughness and slipping must be taken into account accurately for future rheological investigations
Ngo, Thanh Tuan. „Contribution à la mesure de bioimpédance électrique de cellules biologiques par micro-capteurs interdigités : optimisation, conception et validation de capteurs“. Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0077/document.
Der volle Inhalt der QuelleThis thesis focuses on the design and realization of interdigitated sensors for the electrical characterization of the biological medium within the frequency range: 100 kHz - 10 MHz. The main objective of this thesis is to optimize the geometry of the sensor structure according to the specificities of the interdigitated electrodes structure. This optimization leads to widen the measurement frequency range by reducing the effects of polarization at low frequency. The first chapter synthesizes the basics and fundamentals relative to the electric behavior of biological tissues as well as to their electric properties. The second chapter concerns a theoretical approach for the optimization of the sensor to widen the useful frequency band of measurement; this chapter also presents a new method to determine the parameters of the double layer at the contact interface between the electrodes and the biological medium. A three-dimensional modelling of the system, the electrodes being loaded with a biological medium, is implemented using ConventorWare® software and the results discussed in the third chapter. The results obtained allow us to evaluate the influence of the geometrical parameters of the interdigitated structure of the sensor as well as the dielectric properties of the medium on the bioelectric impedance. In the fourth chapter, the devices developed during this thesis are described. The design and the manufacturing of components are presented. The last chapter deals with the experimental measurements obtained with very small volumes of the different solutions (standard solutions, human blood) using five micro sensors that we built in the laboratory. The measurements as well as the validation of the theoretical approach are discussed. Finally we have compared our results with published values in the literature and validated our experimental and theoretical approaches developed in this work
Ngo, Thanh Tuan. „Contribution à la mesure de bioimpédance électrique de cellules biologiques par micro-capteurs interdigités : optimisation, conception et validation de capteurs“. Electronic Thesis or Diss., Université de Lorraine, 2015. http://www.theses.fr/2015LORR0077.
Der volle Inhalt der QuelleThis thesis focuses on the design and realization of interdigitated sensors for the electrical characterization of the biological medium within the frequency range: 100 kHz - 10 MHz. The main objective of this thesis is to optimize the geometry of the sensor structure according to the specificities of the interdigitated electrodes structure. This optimization leads to widen the measurement frequency range by reducing the effects of polarization at low frequency. The first chapter synthesizes the basics and fundamentals relative to the electric behavior of biological tissues as well as to their electric properties. The second chapter concerns a theoretical approach for the optimization of the sensor to widen the useful frequency band of measurement; this chapter also presents a new method to determine the parameters of the double layer at the contact interface between the electrodes and the biological medium. A three-dimensional modelling of the system, the electrodes being loaded with a biological medium, is implemented using ConventorWare® software and the results discussed in the third chapter. The results obtained allow us to evaluate the influence of the geometrical parameters of the interdigitated structure of the sensor as well as the dielectric properties of the medium on the bioelectric impedance. In the fourth chapter, the devices developed during this thesis are described. The design and the manufacturing of components are presented. The last chapter deals with the experimental measurements obtained with very small volumes of the different solutions (standard solutions, human blood) using five micro sensors that we built in the laboratory. The measurements as well as the validation of the theoretical approach are discussed. Finally we have compared our results with published values in the literature and validated our experimental and theoretical approaches developed in this work
Yang, Jinyue. „Impedance eduction of acoustic liners with complex sound fields and shear flows“. Electronic Thesis or Diss., Le Mans, 2024. http://www.theses.fr/2024LEMA1023.
Der volle Inhalt der QuelleAcoustic liners are widely used to reduce noise emissions in aircraft engines. The investigation of liners behavior is essential for their development. Impedance eduction is thus commonly implemented to measure its acoustic impedance in presence of flow. The work in this thesis aims to study the performance of the direct eduction method under realistic conditions, especially when considering large ducts, high-order acoustic modes and flow velocities representative of aircraft nacelles. The study is first based on numerical simulations with a multimodal method. Then the MAINE Flow facility is used for experimental validation and demonstration of the proposed methods and conclusions.In large ducts, the sound field is more complex compared to small ducts in the same frequency range. Therefore, the impedance eduction is challenging, and also because it is also perturbed by the background noise due to the presence of flow. The first task is to design microphone arrays for the experimental facility with the aim of performing accurate impedance eduction in large ducts. The second objective is to investigate the effects of shear flow. Impedance eduction is commonly implemented under the hypothesis of uniform mean flow. However, it is reasonable to question the validity of the uniform flow hypothesis, especially when considering large ducts. The third task is to study the influence of the incident sound field. In large ducts, the sound field contains higher-order modes, and different incident waves result in different behavior of the impedance eduction. It is thus necessary to study how the incident acoustic field affects the eduction results in the presence of flow
Jullian, Gauthier. „Diagnostic robuste de pile à combustible PEM par modélisation physique et mesures d’impédance : prise en compte de conditions dynamiques et du vieillissement“. Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAT009/document.
Der volle Inhalt der QuelleThe PEMFC fuel cell is an electrochemical generator that has interesting potential for automotive applications and which use could help to meet pollution challenges. Poor management of system auxiliaries or malfunctions can place the fuel cell under operating conditions that accelerate degradation processes and shorten its useful life. The- operating conditions of the fuel cell core (temperature, humidity and partial pressures) must be monitored to identify as soon as possible and without any error abnormal situations, which is particularly difficult in dynamic operating conditions and during ageing.The aim of this thesis is to provide solutions to this problem. To that end, a robust diagnostic approach of operating conditions without direct measurement, in a dynamic environment and taking ageing into account has been developed.In order to characterize the fuel cell, a campaign of experimental tests on a test bench was carried out during 1000 hours of operation, with and without faults. This test campaign also allowed to verify to what extent the easily accessible polarization curves and impedance spectroscopy depend on the internal operating conditions.The approach developed is based on one hand on the use of a physical fuel cell model that capture its behaviour for given operating conditions and on the other hand on easy-access current, voltage and impedance measurements. Thus, this allows the development of an embedded solution that minimizes the number of sensors required.The differences between the experimental measurements and the outputs computed by the physical fuel cell model – called residuals – are indicators which are sensitive to faults in operating conditions, and insensitive to usual operating dynamic conditions. Two residuals, generated from fuel cell output voltage and high frequency impedance, are used to detect abnormal operating conditions thanks to threshold detection. The choice of the detection threshold levels allows to set the detection performance in terms of good detection and false alarm probabilities.In order to take ageing into account, a degradation module computes the decrease of fuel cell voltage with time so that ageing is taken explicitly into account by residuals.Going beyond detection alone, a method to class the operating conditions faults has also been proposed. It uses a database of residuals from various known faults to train a K-nearest-neighbour classifier, so that faults can be identified and classified.The model developed in the CEA was compared with experiments carried out on the test bench. An experimental determination of the model constants was carried out using electrochemical methods (cyclic voltammetry...) and numerical ones (linear regression). It appears that the model correctly computes voltage and high-frequency impedance, confirming the possible use of this specific model for diagnostic purpose. The method has been tested with optimal thresholds that have been empirically determined. The detection score obtained is 80%. The false alarm rate is less than 5% during the test.The K-NN classifier was then validated on experimental data. The classification score during the 1000h test is around 60% with large disparities depending on the faults. This score is more than 99% for two of the studied faults (high pressures and low humidity), 63% for low pressures but only 20% for a temperature drop or humidity increase.This work concluded that the approach using a physical model diagnosed most faults with a low level of false alarms during 1000 hours of ageing. The search of new measurements to increase the score of poorly diagnosed faults thus improving diagnostic performance is a main perspective
Pottrain, Alexandre. „Caractérisation non linéaire des composants silicium jusque 220 GHz“. Thesis, Lille 1, 2012. http://www.theses.fr/2012LIL10186.
Der volle Inhalt der QuelleMany applications are emerging at millimeter wave frequencies (radar, imaging, satellite or point to point communications). The ‘DotFive’ project gather industries and laboratories working in microelectronics field (STMicroelectronics, Infineon, IMEC, IHP, Dresden University,.) with the aim to product silicon devices with fMAX>500 GHz for year 2013. In this context, STMicroelectronics recently published results on SiGe HBT showing fMAX>400 GHz. The state of the art in this field is 0.5 THz (Dotfive). Thanks to these high performances, silicon technology seems to be a good challenger for millimeter wave applications. Main advantages of this technology are its ability to propose low cost production and the capability to integrate digital and radiofrequency applications on a single chip. However, non linear performances of the silicon technology have never been studied at millimeter wave frequencies. To this aim, non linear test bench are needed. Before this PhD, I.E.M.N. and STMicroelectronics were limited to 40 GHz. Thus, the goal of this thesis focus on the development of load pull test bench up to 220 GHz. First a W band (75 GHz-110 GHz) load pull test bench has been developed. The main innovation is the ability to extract non linear S11 parameter, in order to obtain an extremely high precision. Then, a G band load pull test bench has been developed with integrated impedance tuner for load impedance variation. The use of integrated impedance tuner was justified by unavailability of external tuner and the high probe losses at these frequencies. The designed integrated tuners have to respect fixed specifications for covered smith chart area and linearity. Due to the difficulty to find fast power measurement devices, we also developed a diode detector on III-V technology.These previously developed test bench allow studies on non linear behavior of CMOS and BiCMOS devices and on the mains physical effects (thermal effect, breakdown,…) which limit power performances from DC to 200 GHz. We will see that BiCMOS technology offer state of the art power density measured at 94 GHz. Finally, integration of a complete load pull test bench on silicon wafer is envisaged. This work have been done for the common laboratory I.E.M.N./STMicroelectronics
Chevalier, Stéphane. „Modélisation multiphysique de l’impédance des piles à combustible PEM. : application au diagnostic de stack par spectroscopie : application au diagnostic de stack par spectroscopie“. Nantes, 2013. http://archive.bu.univ-nantes.fr/pollux/show.action?id=d7a3ce70-8571-414b-aadc-4b97c799e785.
Der volle Inhalt der QuellePhlippoteau, Vincent. „Outils et Méthodes pour le diagnostic d’un état de santé d’une pile à combustible“. Thesis, Toulouse, INPT, 2009. http://www.theses.fr/2009INPT013H/document.
Der volle Inhalt der QuelleA fuel cell system transforms the fuel energy into electricity and heat with electrochemical reaction. There are many kinds of fuel cells and we study here the Proton Exchange Fuelcell (PEMFC), which operates between 50°C and 100°C. At the moment, main issues are fuel cells’ life time and its management. Multiple problems can occur such as drying or flooding due to water management, poisoning with impurities in gas, internal deterioration, etc. The objective of this thesis is to define and carry out experimental and analysing methods to characterize these problems. These experimental methods use electrical perturbation and measurements of their effects. Impedance Spectroscopy is part of these methods, but is greatly improved for instable system (patent). We used two types of tests: low amplitude signal, which can be performed during normal operation of the fuel cell, and large amplitude signal which have a strong impact on the fuel cell response. These tests are complementary and are able to evaluate the state of health of the fuel cell. The analysing process of these measurements is ameliorated, in order to improve the uniqueness of the results. At the end, some problems are generated (drying, flooding, etc) and these methods are performed to follow the variation of performance and determine which parameter is involved with the deterioration