Tesis sobre el tema "Détecteurs de gaz – Matériaux"
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Bouhadid, Myriam. "Conception, caractérisation et mise en œuvre de matériaux organiques conducteurs pour des applications dans le domaine des capteurs chimiques". Pau, 2008. http://tel.archives-ouvertes.fr/docs/00/41/98/89/PDF/TheseBouhadid.pdf.
Texto completoThe main objective of this project was to prepare, study and test new generation of chemical sensors based on conducting polymer composite material. All the steps concerning the feasibility of the sensors have been studied. The active layer was made of composite containing intrinsically conducting polymers as polyaniline (Pani). The synthesis of the conducting composites was optimized and obtained with an environmental friendly process (no acid nor organic solvent) at low cost and thus easy to scale up. Several composites made of polyacrylate/polyaniline were obtained, parameters as dopant chemical nature and polyaniline content were studied. To answer the fundamental questions and to reach the applications mentioned, the structure and several physico-chemical properties (composite formulation, response to gas exposure, signal treatment…) were studied in details on samples and devices that are prepared and characterized in a systematic and controlled way. The procedure to test these new sensors has been optimized in a climatic chamber previously calibrated to control the temperature, the relative humidity and the ammonia concentration parameters. Performances of the sensors were then carried out in terms of reproducibility, sensibility, reversibility, selectivity… Effects of specific conditions as humidity, temperature, and more commonly ageing study were studied and the sensor response was recorded to certify the gas sensor safe for use in hazardous location. This study demonstrated the feasibility of whole polymer (polyaniline composite) sensors to detect ammonia. Moreover, all the performances of this new chemical sensor are in line with the market needs in terms of response time, sensitivity, reproducibility. At last, these sensors introduce a breakthrough technology since their response is reversible with no need of servicing or calibration between two exposures. This feature is very interesting in terms of time-life and cost
Jouve, Christophe. "Etude de matériaux composites dans des structures : métal-composite-métal, métal-composite-semiconducteur : application aux capteurs en phase gazeuse". Lyon 1, 1993. http://www.theses.fr/1993LYO10232.
Texto completoSaoudi, Hanen. "Synthèse et caractérisation des matériaux La0,8Ca0,1Pb0,1Fe1-xCoxO3 (0,00 ≤ x ≤ 0,20) : application dans le domaine de capteurs de gaz de NH3 et CO". Electronic Thesis or Diss., Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0381.
Texto completoThis thesis deals with the elaboration and study of the effect of iron substitution by cobalt on the physical properties (structural, morphological and magnetic) and particularly the detection of the two reducing gases NH3 and CO of the compounds La0.8Ca0.1Pb0.1Fe1-xCoxO3 (x = 0.00, 0.05, 0.10, 0.15 and 0.20). The decrease of valume was subsequently confirmed by the SGGA + U approximation using the Density Functional Theory (DFT). Similarly, the morphological study reveals porous micrographs presenting aggregated and agglomerated particles of nanometric size and irregular shape. Structural and morphological analyzes predicted that the compound with x = 0.05 could be considered as a good candidate for application in the field of gas detection. The results of the electrical measurements have shown that the resistance decreases for Co rate below 0.10 and then increases with higher rate. Similarly, electrical responses under gas have shown that our compounds are able to detect gases, with a variation of the electrical resistance easily measurable following exposure under different concentrations of both gases (NH3 and CO) and to deduce that the compound La0.8Ca0.1Pb0.1Fe0.95Co0.05O3 (x = 0.05) presents the best response towards the two tested gases
Cailleaux, Xavier. "Élaboration, caractérisation structurale et mesures électriques de matériaux oxynitrures semiconducteurs pour application comme capteurs chimiques de gaz". Rennes 1, 2008. http://www.theses.fr/2008REN1S178.
Texto completoGallium nitride (GaN), gallium oxynitride (GaON) and zinc and germanium oxynitride (ZnGeON) have been prepared by ammonolysis of various oxides precursors : commercial powder and precursors prepared by soft chemistry process or solid state reaction. These (oxy)nitride semiconductors have been prepared and then characterized. A comparative structural study has been carried out on GaN and GaON using XRD and Raman spectroscopy to determine GaON crystallographic structure. We found that GaON prepared from nickel gallate NiGa₂O₄ crystalises in a carborundum II structure (6H-SiC). Dip coating technology has been studied as an alternative to screen printing technology, and allowed the preparation of ZnGeON based chemical sensors. Dip coated ZnGeON sensors of 35 µm thickness have been studied for detection of carbon monoxide and carbon dioxide at a concentration of 100 ppm. Electrical characterizations showed that ZnGeON sensors have interesting detection properties, especially in the case of carbon monoxide where we observed a very high sensitivity between 150 and 200°C
Saoudi, Hanen. "Synthèse et caractérisation des matériaux La0,8Ca0,1Pb0,1Fe1-xCoxO3 (0,00 ≤ x ≤ 0,20) : application dans le domaine de capteurs de gaz de NH3 et CO". Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0381/document.
Texto completoThis thesis deals with the elaboration and study of the effect of iron substitution by cobalt on the physical properties (structural, morphological and magnetic) and particularly the detection of the two reducing gases NH3 and CO of the compounds La0.8Ca0.1Pb0.1Fe1-xCoxO3 (x = 0.00, 0.05, 0.10, 0.15 and 0.20). The decrease of valume was subsequently confirmed by the SGGA + U approximation using the Density Functional Theory (DFT). Similarly, the morphological study reveals porous micrographs presenting aggregated and agglomerated particles of nanometric size and irregular shape. Structural and morphological analyzes predicted that the compound with x = 0.05 could be considered as a good candidate for application in the field of gas detection. The results of the electrical measurements have shown that the resistance decreases for Co rate below 0.10 and then increases with higher rate. Similarly, electrical responses under gas have shown that our compounds are able to detect gases, with a variation of the electrical resistance easily measurable following exposure under different concentrations of both gases (NH3 and CO) and to deduce that the compound La0.8Ca0.1Pb0.1Fe0.95Co0.05O3 (x = 0.05) presents the best response towards the two tested gases
Lee, Szu-Hsuan. "Capteurs de gaz sélectifs à base de matériaux hybrides organooxoétain et d'oxyde d'étain". Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0034.
Texto completoThe ultimate objective of this research is to draw new prospects in the gas sensing field by finely tuning the chemical nature, the texture and the morphology of the active layer to develop new type selective gas sensors. High gas selectivity has been a challenging issue during the past decades in the gas sensing area. Our approach is based on the design of molecular single precursors – alkynylorganotins which contain suitable functionalities required to obtain stable hybrid materials by the sol-gel method exhibiting selective gas detection towards harmful/toxic gases. Their gas sensing properties have been compared with those of tin dioxide (SnO2) nanoparticles synthesized by the hydrothermal route. A series of functional organooxotin-based materials have been processed as films by the spin or drop coating method and characterized by XRD, FT-IR, RAMAN, AFM, SEM, TEM, N2 sorption and TGA-DTA measurements. Gas sensing studies show that one of the hybrid organotin oxides exhibits an outstanding selective gas sensing response towards various gases, such as CO, H2, ethanol, acetone and NO2 whereas SnO2 nanoparticles present non-selective gas sensing ability under the same experimental condition. Thus, the best gas selectivity toward CO (at 100 and 200 ppm), H2 (at 100, 200 and 400 ppm) and NO2 (at 1, 2, 4 and 8 ppm) was achieved at 100 °C for the hybrid organooxotin-based film, however, it showed no response to ethanol/acetone at the same working temperature. On the other hand, the nanoparticulate SnO2 films prepared are sensitive to all the gases tested at low concentrations (CO: 10~100 ppm; NO2: 0.5~4 ppm; H2: 100~800 ppm; acetone: 25~200 ppm; ethanol: 10~100 ppm) in an operating temperature range from 200 to 400 °C. Moreover, the selectivity of SnO2 materials towards NO2 (between 0.5 ~ 4 ppm) can be optimized by well-manipulating the sensing temperatures. Finally, both organooxotin-based and tin oxide-based materials display superior gas sensing ability at low gas concentrations which opens a fully new class of gas sensing materials as well as a new possibility to integrate organic functionality in gas sensing metal oxides
Fernandes, de Medeiros Indira Aritana. "Nanostructuration de ferrites de cobalt CoxFe3-xO4 : Effets sur la catalyse et la détection de gaz polluants". Electronic Thesis or Diss., Toulon, 2018. http://www.theses.fr/2018TOUL0007.
Texto completoDifferent synthesis methods such as hydrothermal, solvothermal and thermal decomposition were developed to control nanoparticles shape and composition. The influence of synthesis parameters such as the nature of surfactants, the solvents, temperature and time of synthesis were also investigated. The powders were characterized by X-ray Diffraction and Transmission Electron Microscopy coupled with Dispersive Energy Spectroscopy. The catalytic and detection properties were evaluated in presence of CO and NO2 in synthetic air. CoxFe3-xO4 (x = 1, 1.5 ) nanooctahedra with 15-20 nm were produced by hydrothermal synthesis using different surfactants (CTAB, SDS and PVP). Nanocubes of CoFe2O4 were successfully obtained by solvothermal synthesis using oleylamine as surfactant. Nanooctahedra of CoxFe3-xO4 with x = 1.5 have higher activity for the CO conversion than those with x=1, and the conversion starts at lower temperature for the nanocubes. The nanocubes show lower sensitivity for the detection of NO2 than the nanooctahedra which indicates that the {111} faces are more reactive than the {100} ones in cobalt ferrites nanoparticles
Klingenfus, Jérôme. "Compréhension et prédiction des réponses de capteurs chimiques de gaz à surface de matériaux sensibles : application aux polysiloxanes fonctionnalisés". Thesis, Tours, 2011. http://www.theses.fr/2011TOUR4051/document.
Texto completoThe aim of this study is to understand and model the responses of coated chemical sensors for gas phase detection. The work exposed here focuses on quartz crystal microbalance (QCM) coated with functionalized polysiloxanes. Measurements were carried with the QCM exposed to organic vapours when equilibrium was reached. It has been shown that selectivity depends on the material used. To understand that selectivity, each step involved in the detection has been investigated. First of all, with PM-IRRAS, we verified that the frequency shift was proportional to the amount of absorbed analyte. Then, affinity in liquid phase has been determined through a new methodology by NMR. It has also been used, on model system to prove the applicability of Hansen solubility coefficient to calculate mixing free enthalpy. For polymers, those coefficients have been determined using NMR combined with group contribution methods. Based on these descriptors, a numerical model has been built to calculate a priori the performance of a sensor based on, the chemical structure of the sensitive material and of the detected compound
Liu, Zhaoting. "Synthesis, characterization and properties of wood-templated oxides with hierarchical porous structures". Troyes, 2009. http://www.theses.fr/2009TROY0004.
Texto completoHierarchical porous materials have displayed important researching and application values at the fields of separation and purification, selective adsorption, optical function, and sensor design etc. Some preparation methods have been designed to fabricate porous materials. But these traditional methods have to use specific equipments and complicated techniques, and obtained porous materials have single pore size distributions with single functions. The morph-genetic transformation technology is a simple processing technology to fabricate re-fined hierarchical porous materials using organ-isms as template. The organisms in nature are the perfect unities of highly delicate structures and effectively complex functions through mil-lions of years of evolution and natural survival law, which prepare plentiful structural tem-plates for hierarchical porous materials. In the present work, wood-templated Fe2O3, ZnO and NiO with hierarchical porous structures were fabricated through replication wood’s morphology and structure. The synthetic mechanism was studied to optimize the parameters of morph-genetic technology, and wood-templated oxides with wood’s structures were fabricated successfully. The porous structures in multi-scales, the optical properties and the gas sensing properties of wood-templated oxides were researched in detail
Carquigny, Stéphanie. "Conception, caractérisation et mise en œuvre de matériaux organiques conducteurs pour le développement de capteurs de gaz pour l’environnement". Thesis, Lille 1, 2011. http://www.theses.fr/2011LIL10177/document.
Texto completoAs part of the research topic of the Department of Chemistry and Environment at Ecole des Mines de Douai on the development of sensors for gaseous pollutants, previous thesis had enabled the development of a chemical sensor of ammonia with a minimum detectable concentration of 10 ppm, a reversible response and a lifetime of more than 3 years, responding to the major flaw of the electrochemical cells of the market. The sensitive surface of the sensor synthesized in a clean way for the environment, consists mainly of an intrinsically conductive polymer whose electrical resistance varies in proportion to gas concentration.The objective in this thesis is double: on the one hand improve the metrological performance of the ammonia sensor, on the other hand change its sensitive surface by an appropriate method for the specific detection of formaldehyde.For the first objective, different influence parameters such as temperature, relative humidity, wind speed and interfering gases were first evaluated, then the detection threshold was reduced by a factor of 100 by the realization of thin films on interdigitated electrodes. The performances of different syntheses were compared and finally, the robustness of these sensors has been tested in piggeries, which are among the major contributors of ammonia emissions. For the second objective, more sensitive and selective compounds to formaldehyde were introduced into the sensitive surface of the sensor and tested. The fluoral p was finally selected. The first results showed sensitivity to formaldehyde proportional to its concentration, with a detection limit of a few ppm and a response time less than one minute. The concept used here is innovative and demonstrates the feasibility of formaldehyde detection based on the simple measure of changes in electrical resistance of the sensitive film made. The detection limit must still be decreased to respond to the problem of measuring formaldehyde indoor
Kerlau, Marie. "Nouveaux matériaux pour capteurs chimiques de gaz dans les systèmes Ga-O-N et Ta-O-N : Synthèse, caractérisation et mise en forme (couches épaisses, couches minces). Application à la détection de gaz toxiques et explosifs". Rennes 1, 2003. http://www.theses.fr/2003REN10080.
Texto completoLe, Guevel Xavier. "Elaboration de sols de silice colloïdale en milieu aqueux : fonctionnalisation, propriétés optiques et de détection chimique des revêtements correspondants". Tours, 2006. http://www.theses.fr/2006TOUR4005.
Texto completoThe aim of this work was to study surface reactivity of silice nanoparticles through physical and chemical properties of sols and coatings. Appliatons are numerous and they are illustrated in this work by optical coating preparation for laser components and chemical gas sensor development for nitroaromatics detection
Aneflous, Latifa. "Systèmes nano- et micro-structurés à base de dioxyde de cérium et de sesquixyde de néodyme : propriétés électriques et catalytiques des solutions solides Ce1-xNdxO2-delta". Toulon, 2005. http://www.theses.fr/2005TOUL0004.
Texto completoTHe dioxide of cerium is used as gas sensor. Twos systems based on oxides of Ce(+IV) and of Nd(+III) are studied : a multiphase and nonostructured system, obtained by soft chemistry, at low temperature, starting from oxalates and of acetates ; a ceramics with micrometric granulometry, obtained after sintering of the nanostructured powders, to 1600°C. The structures are elucidated by DRX. Morphology is chacterized by MET coupled with the EDAX. The electric properties according to the composition in the temperature range 40-700°C are measured by SIE. With the top of 400°C, the contributions of the bulks grain boundaries and electodes are separate. Eponent n of model CPE is related to the microstructure. Conductivity reaches a maximum with neodymium 10%. The catalytic properties are studied for air-methane mixtures by spectroscopy IRTF. Measurements of conversion of methane show that these catalysts are very active at 350°C
Fernandes, de Medeiros Indira Aritana. "Nanostructuration de ferrites de cobalt CoxFe3-xO4 : Effets sur la catalyse et la détection de gaz polluants". Thesis, Toulon, 2018. http://www.theses.fr/2018TOUL0007/document.
Texto completoDifferent synthesis methods such as hydrothermal, solvothermal and thermal decomposition were developed to control nanoparticles shape and composition. The influence of synthesis parameters such as the nature of surfactants, the solvents, temperature and time of synthesis were also investigated. The powders were characterized by X-ray Diffraction and Transmission Electron Microscopy coupled with Dispersive Energy Spectroscopy. The catalytic and detection properties were evaluated in presence of CO and NO2 in synthetic air. CoxFe3-xO4 (x = 1, 1.5 ) nanooctahedra with 15-20 nm were produced by hydrothermal synthesis using different surfactants (CTAB, SDS and PVP). Nanocubes of CoFe2O4 were successfully obtained by solvothermal synthesis using oleylamine as surfactant. Nanooctahedra of CoxFe3-xO4 with x = 1.5 have higher activity for the CO conversion than those with x=1, and the conversion starts at lower temperature for the nanocubes. The nanocubes show lower sensitivity for the detection of NO2 than the nanooctahedra which indicates that the {111} faces are more reactive than the {100} ones in cobalt ferrites nanoparticles
Perrot, Virginie. "Méthode innovante de croissance de couches minces de MOF par CVD pour la détection de gaz". Thesis, Lyon, 2021. http://www.theses.fr/2021LYSE1331.
Texto completoOn-site and real-time measurement of gas concentrations are crucial for both the understanding and the monitoring of industrial and environmental processes. In recent years, there is an increasing need to develop portable multi-gas analysis tools allowing in situ detection of complex gas mixtures mainly due to safety, process and environmental considerations. A promising approach is based on the integration of the different parts of the analytical system (i.e. pre-concentrator, gas chromatography column, gravimetric sensors) in a silicon die by using standard microelectronic technologies. Each of these devices need to be coated by an appropriate functional layer. Metal Organic Frameworks (MOF), hybrid microporous crystalline materials with tuneable properties, are attractive for this type of application regarding their high specific surface area and chemical stability. However, these materials are usually synthetized via solvothermal techniques, which complicates the growth of continuous thin films and their integration in micro-devices. This work focuses on the development of a vapor phase-based route to produce Zeolitic Imidazolate Framework 8 (ZIF-8) thin films, a MOF of particular interest. The growth method is based on the deposition of ZnO layers by atomic layer deposition (ALD) on a substrate followed by ZIF-8 formation using cyclic exposure to water vapour and organic ligand in the gas phase. This approach allowed formation of thin films with tunable thickness between 5 and 200 nm, independently of the initial ZnO thickness. The impact of the process parameters (temperature of the substrate, water vapor pressure…) on the MOF growth was studied. The composition, morphology and crystallinity were examined using a wide range of characterization techniques (AFM, SEM, XRD and FTIR). Moreover, the growth mechanism was investigated by XPS and ToF-SIMS to understand the role of water during the reaction and several hypotheses were given. Finally, the as-synthesized films were thermally activated and the porosity was assessed using ellipsometric-porosimetry. Pore volume represents 30 % of the volume of the films in some cases. The adsorption properties of the films were also investigated using gravimetric gas sensors. Indeed, ZIF-8 films were grown on quartz crystal microbalance to study the interactions between the layer and several gases (methanol, acetone and water) in order to determine the benefit of ZIF-8 thin films in sensors. This work shows that the sensors coated with the ZIF-8 enable the detection of all the gases independently in the range of concentration tested. However, the sensitivity of the methanol detection is highly impacted by the addition of relative humidity
Romanytsia, Ivan. "Etude des propriétés électro-catalytiques des matériaux d’électrode et des phénomènes de polarisation pour la compréhension des mécanismes de détection d'un capteur d'oxydes d'azote et l'optimisation de son fonctionnement". Thesis, Saint-Etienne, EMSE, 2014. http://www.theses.fr/2014EMSE0760.
Texto completoRoad transport is one of the main sources of NOx emitted into the atmosphere. The majority of this pollution is concentrated in urbanized areas. The permanent exposure to the exhaust gases has serious consequences for human health and for that, emission standards become more stringent. The modern technologies present in automotive need the continuous control of the exhaust composition. The variations of temperature, composition of exhaust gas, vibrations and other factors require long life robust control systems. In this work, we present the procedure of fabrication and characterization of an electrochemical sensor with three electrodes that can fulfill the demands of industrial applications in automotive industry. Manufacturing by screen-Printing technology allows producing low-Cost sensor with high reproducibility in industrial process.The principle of our sensor is based on galvanostatic polarization of a gold sensing electrode allowing the selective detection of NO2 without interference to other gases such as CO and NO. In order to increase stability, and to decrease the response and recovery time of the sensor, a new Au composite sensitive electrode was developed. The electrochemical reduction of oxygen on gold and gold-Based electrodes was then studied, to propose a detailed mechanism of NO2 detection
Bahoumina, Prince. "Développement d’une plateforme de détection de gaz, utilisant un capteur différentiel flexible imprimé à transducteurs micro-ondes et matériaux composites carbonés". Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0101/document.
Texto completoSince the Industrial Revolution, the levels of atmospheric concentrations of greenhouse gases have been increasing, causing an acceleration of global warming. Volatile organic compounds (VOCs) contribute not only to this greenhouse effect, but also to environmental pollution, which has a negative impact on all living species on the planet. For example, in the year 2012, air pollution caused 7 million deaths, according to the World Health Organization (WHO) [1]. In addition, a very recent medical study by the Lancet Commission on Pollution and Health found that one in six deaths in 2015 was related to air and water pollution [2]. Also, indoor and outdoor air pollution is linked to 6.5 million deaths worldwide each year. VOCs can indirectly cause cough, chest discomfort, painful discomfort, shortness of breath, as well as nasal, ocular or throat irritation. They can also be directly toxic or explosive or disruptive of the immune response. In addition, some of them are classified as CMR (carcinogenic, mutagenic and reprotoxic). They are very volatile and often used as solvents for example. In these conditions, a better understanding of the health and environmental effects of exposure to VOCs is necessary. Such knowledge also involves the detection and quantification of VOC concentrations in order to propose a better management of the environments and to alert people in real time of the dangers incurred. Most of the existing or commercially available platforms are either too expensive, energy intensive, high temperature functional, unstable for real-time or long-term detection, which limits the proliferation of measurement sites. This thesis is in the field of dedicated gas sensors for the detection of pollution in the air. It deals with the development of a platform for the detection, monitoring and quantification of volatile organic compounds (VOCs) in real time, using a flexible and printed differential gas sensor based on microwave transducers and composite polymeric carbon materials as sensitive layers. The proposed device aims at providing directly exploitable information such as a low-cost embedded platform dedicated to the Internet of things and which offers increasing possibilities for the proliferation of detection and control sites by realizing networks of wireless communicating sensors operating in various environments
Mikhaylov, Sergei. "Synthesis and investigation of nanostructured conducting polymers based nanocomposites for ammonia and amines detection". Thesis, Lille 1, 2017. http://www.theses.fr/2017LIL10036/document.
Texto completoThe thesis is devoted to the synthesis and investigation of properties of inorganic-organic polyaniline (PANI) and polypyrrole (PPy) based hybrid materials with TiO2 (rutile and anatase) and SnO2 nanoparticles applicable for ammonia and amines detection. The direct polymer growth on the surface of nanoparticles allowed obtaining of nanocomposite materials with a “core-shell” structure which differs from simple mechanical mixture by more uniform polymer distribution and stronger interaction between source components.The object of research is the process of formation of polyaniline and polypyrrole nanocomposites with metal oxides. The research goal is to reveal formation peculiarities and properties of nanostructured composite materials based on conducting polymers and metal oxides nanoparticles that are sensitive to ammonia and amines. Research methods include RedOx and pH monitoring, FTIR and UV-spectroscopy, SEM, TEM, thermogravimetry, liquid chromatography, conductivity measurements and sensor tests.The new approach to study kinetics of aniline polymerization process by simultaneous RedOx and pH monitoring of reaction medium was proposed. For the first time the influence of sulfonic acids and metal oxides on the aniline polymerization process and molecular characteristics of the obtained polymer was shown. For the first time a linear correlation between the nanoparticles content and reciprocal duration of separate stages of polymerization was shown. Formed "core-shell" nanocomposites have sensitivity to ammonia and amines of about 2 times higher than the pure polymer. Developed new materials can be used in the manufacturing of chemoresistive sensors' active layers
Baklouti, Linda. "Capteurs à base d'assemblages discontinus organisés pour la détection spécifique de gaz". Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTT198/document.
Texto completoGas sensing and monitoring are important issues for both industrial safety and protection of the environment and human beings. Dihydrogen, is increasingly used as fuel and energy carrier but it is extremely flammable and explosive in a wide range between 4 and 75% in air.Similarly, ammonia is widely used in industry as a cooling gas or as a reagent for the chemical production of other compounds.This gas presents risks to the environment and to living beings and can form explosive mixtures with air within 15 to 28% by volume.Gas sensors, indicating the presence and /or quantification of these gases, are very important.In continuation of our work on resistive sensors based on discontinuous assembly of nano-objects, the aim of this thesis was to prepare resistive sensors for the detection of H2 and NH3.These sensors are based on 2D assemblies of complex compositions of nanoparticles. Three types of core-shell nanoparticles were synthesized: Au@ZnO, Au@SnO2 and Au@Ag. Different physicochemical techniques (UV-Visible / TEM / DRX etc.) were used to characterize the particles. The next step was to assemble them in compact monolayers. The films were obtained by Langmuir-Blodgett assembling technique. Then, they were transferred to the surface of a glass slide supporting interdigitated electrodes. Sensing performances of the as-fabricated resistive sensor were evaluated.Sensors based on Au@ZnO and Au@SnO2 nanoparticles were tested towards H2, while Au@Ag based sensors were tested under NH3.The sensors showed attractive performances in H2 and NH3 detection within wide concentration ranges. Another important contribution of this work is the understanding of detection mechanisms. Various analytical techniques such as TPD (Temperature Programmed Desorption) and TPR (temperature programmed reduction) were used for the discussion of the mechanisms involved
Stoeckel, Marc-Antoine. "Propriétés physico-chimiques et électroniques des interfaces supramoléculaires hybrides". Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAF002/document.
Texto completoThe work realized during this thesis was oriented toward the comprehension of the charge transport mechanism involved in organic electronics, and on the engineering of the semiconducting properties of hybrid supramolecular interfaces. Firstly, the intrinsic origin of the charge transport properties was studied for two semiconducting small molecules which are similar in terms of chemical structure but exhibit different electrical properties. Secondly, the electronic properties of 2D material were modulated with the help of self-assembled monolayers inducing antagonist doping properties. Finally, hybrid perovskites and semiconducting small molecules were used as active materials in oxygen and humidity sensing respectively, forming high-performance sensors. All the project employed the principles of the supramolecular chemistry in their realisation
Doubi, Youssef. "Amélioration du procédé de fabrication des couches hybrides d'oxyde metallique et de nanomatériaux pour la quantification du formaldéhyde". Electronic Thesis or Diss., Université de Lorraine, 2023. https://docnum.univ-lorraine.fr/ulprive/DDOC_T_2023_0317_DOUBI.pdf.
Texto completoIn this work we interested in the development and characterization of binary materials with n-type conductivity TiO2 and SnO2 for gas sensor applications. We have chosen these materials because of their availability and their structural, morphological, optical and electrical characteristics, which are suitable for gas sensor applications. TiO2 and SnO2 thin layers have been deposited by spray pyrolysis in ambient air. Using the classical method, we studied the effect of certain factors on TiO2 and SnO2 physicochemical properties. The samples were analyzed using various techniques such as XRD, Raman, EDS, SEM, UV-Visible and the two-tip method. The results of these studies showed that the SnO2 and TiO2 thin films are well crystallized in anatase and rutile phases respectively, with preferential orientations along the (101) and (110) planes. Raman spectroscopy confirmed the purity of these materials by the presence of peaks characteristics of these phases, while UV- Visible was proved the semiconducting properties of SnO2 and TiO2. The L9 Taguchi table method was used to optimize the number of experiments in order to determine the right processing conditions leading to the best properties of TiO2 and SnO2 in thin films. The results of the Taguchi method showed a significant improvement in the SnO2 and TiO2 properties compared with the conventional method. Our gas sensors prepared on the basis of TiO2, SnO2 and Ti⁴⁺ doped SnO2 thin films respond to NO2 at room temperature, and the SnO2-based sensors respond better than TiO2 to this gas. The sensor made from a thin layer of SnO2 doped with 5% Ti⁴⁺ and operated at 200°C had the highest sensitivities to the low concentrations of H2S
Appert, Florian. "Conception et réalisation de détecteurs dédiés à l'analyse de couches minces par spectrométrie Mossbauer : application à l'étude des propriétés magnétiques de films d'oxydes multiferroïques". Thesis, Normandie, 2017. http://www.theses.fr/2017NORMR133/document.
Texto completoThis work is devoted to the development of two Mössbauer detectors dedicated to thin films studies by conversion electron Mössbauer spectrometry (CEMS), and to their use for the characterization of bismuth ferrite BiFeO3 (BFO) epitaxials thin films. The first designed instrument is composed of a proportional counter and a thermoelectric module. It allows CEMS acquisitions of Mössbauer spectra from 245 to 375K with an external magnetic field upto 1.4 T. The second device is based on a commercial channeltron™ and a continuous flow cryostat allowing measurements downto 4 K. The CEMS measurements have been performed on (110) and (001) oriented BFO layers with various thickness deposited on LaAlO3 et SrTiO3 substrates. Beyond a critical thickness, the (110) BFO exhibits a mixing of collinear and cycloidal magnetic phases. The collinear phase shows an anisotropy axis [001] direction which is located in the sample plane. The cycloid propagation plane have been found to be perpendicular to the sample plane. Both epitaxial strain and size effects have been proposed to explain the cycloid destabilization in the thinner films. In (001) BFO thin films, exhibiting a BFO tetragonal phase, the CEMS measurements have shown that the magnetic ordering temperature tends to decrease with the layer thickness
Renard, Laëtitia. "Nanostructured tin-based materials : sensing and optical applications". Thesis, Bordeaux 1, 2010. http://www.theses.fr/2010BOR14183/document.
Texto completoClass II hybrid materials were prepared from ditin hexaalkynides. Two families of precursors, including either hydrocarbon or oligothiophene-based spacers, were obtained and led by the sol-gel process to self-assembled organotin-based hybrid materials made of planes of oxide separated by organic bridges. Thus, the rigid thienyl spacer gave rise to a “pseudo-lamellar” structure that showed a monomer emission band with a rather small red-shift compared with to the emission of the precursor in solution. However more disordered thienyl xerogels led to broad emission features assigned to excimer or dimer formation. Moreover, thin films containing alkylene- and arylalkylene bridged have been prepared and showed a “pseudoparticulate” porous morphology and a short-range hierarchical order in the organic-inorganic SnOx pseudoparticles. Unexpectedly these hybrid thin films detect hydrogen gas at a temperature as low as 50 °C at the 200-10000 ppm level. From these hybrid thin films, crystalline tin dioxide (SnO2) were prepared by a thermal post-treatment. As expected, cassiterite SnO2 films detected H2 and to a less extent CO with a best operating temperature comprised between 300 and 350 °C
Delpha, Claude. "Contribution au développement d'un système multiplicateurs de gaz : application à la détection de gaz réfrigérant Forane 134a et de gaz carbonique dans une atmosphère conditionnée humide". Metz, 2000. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/2000/Delpha.Claude.SMZ0031.pdf.
Texto completoThe development of gas multisensor systems (electronic noses) has now an increasing interest in many field of application. In the field of atmospheric anti-pollution control our study consists in the main detection of a refrigerant gas Forane 134a and carbon dioxide in a humidity controlled atmosphere. We first give the state of the art on electronic noses and gas sensors, and then we present to justify our choice for array of tin dioxide (SnO2) sensors from FIGARO Engineering Inc. We mention the main constraints for their use allowing us to define the experimental set-up useful to their study. We show the importance of this set-up by noting the errors and other lack of precision which can be induced in the measurements if a good control is not correctly operated. Afterwards, we give the characterization results of the chosen sensor types for the different possible atmospheres : dry or wet synthetic air mixed with various concentrations of our two target gases R134 and CO2 and their mixture. We underline the reducing type response of the sensor in presence of humidity or R134a, and the oxidising type response CO2. We also show the influence of the relative humidity on the alone or mixed studied gases. From this characterization two main representative variables are extracted : the steady-state conductance and the conductance dynamic slope. The system learning data base is then built and we show that the association of the reference gas conductance as a variable with the two other types allow us to reduce the drift effects during the treatment with multivariate data analysis methods (Principal Component Analysis and Discriminant Factorial Analysis). Finally we propose decisive laws for the identification of the target gases and also their possible quantification. These laws allowed us the successful identification (more than 99%) of unknown test cases
Potdevin, Guillaume. "Développement de photocathode de meilleures efficacitées quantiques pour détecteurs à gaz". Université Joseph Fourier (Grenoble), 2008. http://www.theses.fr/2008GRE10009.
Texto completoThis work concerned the development of a new generation of photocathodes for X-rays gas filled detectors. The thesis contains a description of the monte carlo studies, as well as experimental tests of various photocathodes which were carried out during the thesis work. Last, interesting results concerning CsI3 as an interesting precursor to CsI (as a secondary emitter) are given
Gautheron, Benoît. "Elaboration de couches minces de SnO2 pures et dopées (Pd, Ni) par pyrolyse d'un aérosol généré par ultrasons. Caractérisations microstructurale et électrique ; application à la détection des gaz". Grenoble INPG, 1992. http://www.theses.fr/1992INPG0160.
Texto completoAkou, Amal. "Matériaux moléculaires bistables : application comme capteurs de gaz". Toulouse 3, 2012. http://thesesups.ups-tlse.fr/1775/.
Texto completoThe spin crossover phenomenon in transition metal complexes is one of the most spectacular examples of molecular bistability. The switching between the two different electronic states of these molecules can be achieved using various external perturbations like a change of temperature or by applying an external pressure, light irradiation, pulsed magnetic field, and even a change of the concentration of chemical species around the samples. Hence the potential applications of these materials for the construction of sensor and memory devices continue to draw much attention. The work developed in this manuscript attempt to answer the various issues to the challenge at nanoscale of SCO materials. Elaboration of thin films, nanopatterns, their engineering of bistable inorganic-materials, and their physical properties are presented. In addition, a new technique to detect the spin crossover phenomenon in the films is developed based on the variation of the diffracted intensity by a periodic pattern of the thin film material due to the change of the optical properties associated with the spin state change. This approach is also used as the protocol for the detection of guest molecules due to interactions of these molecules with SCO network that come to modify the diffraction signal. This thesis is part of an ANR project (CHEMOSWITCH), which aims to explore a multidisciplinary approach (chemical / physical / nanotechnology), the effect and selectivity of gas adsorption (or vapor) on the properties of spin transition of nanomaterials by examining change their optical properties. These nano-objects could be of industrial applications in the field of gas sensors and, more exploratory, could enable the production of devices for photonics (optical filters, waveguides, diffractions addressable networks. . . )
Wierzbowska, Katarzyna Barbara. "Studies of electronic and sensing properties of epitaxial InP surfaces for applications in gas sensor devices". Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2007. http://tel.archives-ouvertes.fr/tel-00926562.
Texto completoCherkaoui, Karim. "Caractérisation de matériaux semi-isolants par spectroscopie de transitoire de courant photoinduit : matériaux InP dopés Fe pour la micro-optoélectronique et CdZnTe pour la détection nucléaire". Lyon, INSA, 1998. http://www.theses.fr/1998ISAL0104.
Texto completoSemi-insulating materials show an increasing interest in many application fields. For instance high resistivity InP and CdZnTe substrates are very promising for micro-optoelectronic circuits and nuclear detectors respectively. We have characterized both materials by means of Photo-Induced Current Transient Spectroscopy. The aim of the first part of this study is to analyze the defects in annealed InP substrates to understand the compensation phenomena in this material. We have detected two levels at 0. 2 eV and 0. 4 eV induced by the thermal treatment. We have noticed the presence of iron in all samples even in non intentionally doped ones. Therefore, one must take into account the Iron contribution to fully understand the compensation mechanism in the annealed InP substrates. In the second part, we have studied the CdZnTe material grown by the High Pressure Bridgman method to point out the defects which may affect the detector performance. Three levels detected near the midgap seem to affect the performance of the first studied detectors. We have characterized a series of detectors in which we have only detected one midgap level. We explain this by an improved material quality. This level is probably responsible of the semi-insulating character of this material. Finally, we correlate the detection performance of a series of samples with the presence of two electron traps at low temperature
Helli, Omar. "Multicapteurs de gaz pour la conception d'un nez électronique de surveillance de la pollution atmosphérique : application à la detection de NO2 et H2S dans une atmosphère humide chargée de CO2". Metz, 2003. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/2003/Helli.Omar.SMZ0303.pdf.
Texto completoMella, Tony. "Procédé d'intégration hétérogène de CdHgTe pour le développement de détecteurs infrarouges refroidis". Thesis, Université Grenoble Alpes, 2021. http://www.theses.fr/2021GRALI036.
Texto completoHgCdTe infrared detectors are currently fabricated with the CdZnTe growth substrate as the mechanical support for the whole process. The brittleness, the cost and the the avaibility on small surfaces make CdZnTe one of the main limiting factors of the production yields.This thesis work focuses on the fabrication of HgCdTe detectors after bonding of the HgCdTe film on a more robust substrate. From the bibliography study, polymer bonding appeared to be the most interesting bonding process for CdHgTe. As the elastic limit of HgCdTe is very low (around 15-20MPa at 300K), studying the thermomecanical stresses generated in a HgCdTe/bonding substrate structure is a key step. COMSOL Multiphysics simulations showed that, amongst the considered substrates, germanium stood out as the best candidate. X-Ray Diffraction measurements, performed with the sin²ψ method developped during this thesis for HgCdTe, showed that bonding generates stresses of around 20MPa on Si and 7MPa on Ge, consistent with simulations results. 80K and 120K measurements show no measurable degradation on neither Si or Ge. XRD performed at 120K at the ENSAM of Metz show stresses in HgCdTe on Si of about 60MPa, which indicates that the elastic limit of the material is equal or higher at this temperature. Stresses are thus only a problem for the process which involves temperatures higher than 300K.Functional diodes have been obtained on HgCdTe films bonded onto Si and Ge, demonstrating the feasability of a fabrication process on a bonded HgCdTe. Current-Voltage measurements performed before hybridization show similar levels of current, and a diffrence of two orders of magnitude is observed after hybridization. More tunnel current is observed on Si under high bias. However, polymer degradation observed during technological annealings have been observed. This work thus shows that processing onto a bonded HgCdTe is viable but another bonding method is necessary in order to have access to the whole range of HgCdTe processes
Camara, El Hadji Malick. "Développement d'un micro-preconcentrateur pour la détection de substances chimiques à l'état de trace en phase gaz". Saint-Etienne, EMSE, 2009. http://tel.archives-ouvertes.fr/tel-00448980.
Texto completoIn the field of gas detection, one major trend is to miniaturize analytical techniques. In such technological developments, the gas pre-conditioning is usually very important. This may involve, firstly, the modification of a gas mixture, for example to improve the selectivity of a detection device, secondly, the effect of preconcentration in order to increase the sensibility of the detector. Indeed, in some applicative environments the concentration of gas is too small and therefore a preconcentration unit at the entrance of the analytical device is needed. When a preconcenrator is used, the gas mixture to be analyzed flows through it and is accumulated during some time, then the mixture is desorbed by a temperature pulse and brought to the detector. This work presents the development of a gas preconcentrator based on a micro-channel in porous and non-porous silicon filled with an adequate adsorbent material by micro-fluidic process in open micro-device or by impregnation in close one. The particularity of this device is its applicability in the fields of atmospheric pollution monitoring (Volatiles Organic Compounds-VOCs) and explosives detection (nitroaromatic compounds). Various designs of micro-devices have been investigated and a special focus has been dedicated to the carbon adsorbent. The optimization of the device and its operation were driven by its future application in outdoor environments. The benefits of using porous silicon to ease the fixing of the carbon absorbent in the reactor and to modify the gas desorption kinetic are also investigated
Faure, Sébastien. "Synthèse et caractérisation de complexes métalliques en série bistétraazamacrocyclique face à face : étude de leurs propriétés photophysiques". Thèse, Université de Sherbrooke, 2004. http://savoirs.usherbrooke.ca/handle/11143/5048.
Texto completoGroboillot, Anne. "Comparaison de capteurs à membrane gazeuse utilisant soit un chromatographe, soit un spectromètre de masse : application au suivi de substances volatiles de procédés de fermentation". Vandoeuvre-les-Nancy, INPL, 1989. http://www.theses.fr/1989NAN10471.
Texto completoMitev, Krasimir. "Modélisation numérique des mécanismes de fonctionnement d'un compteur proportionnel cylindrique utilisé pour la mesure absolue de l'activité volumique du krypton-85". Toulouse 3, 2005. http://www.theses.fr/2005TOU30241.
Texto completoBourrounet-Dubreuil, Brigitte. "Conception et développement d'un système à multiples capteurs de gaz : application en agro-industrie". Toulouse, INPT, 1998. http://www.theses.fr/1998INPT004C.
Texto completoOuld, Daddah Brahim. "Capteurs potentiométriques de gaz carbonique, réalisés en technologie microélectronique hybride "couches épaisses"". Bordeaux 1, 2000. http://www.theses.fr/2000BOR12325.
Texto completoNivot, Christelle. "Densification de l'alumine : frittage sous pression de gaz". Saint-Etienne, EMSE, 2004. http://www.theses.fr/2004EMSE0029.
Texto completoGas pressure sintering is usually used to improve densification of compounds which are thermodynamically unsatble at typical sintering temperatures. The aim of this work is to study stability of pores performed in alumina materials by applying a nitrogen pressure during sintering cycle results on densification and microstructure evolution show that a nitrogen presure (between 2 MPa and 6 MPa) mainly delays necks formation and consolidation during initial stage of sintering. Indeed, pore closure and grain growth are not altered by nitrogen pressure during intermediate and final stages of sintering. Up to final relative densities of about 95%, modelling comparison points out densification controlled by grain boundaries diffusion whatever the pressure applied. Furthermore, this study underlined the importance of grain size evolution plotted versus relative density. This representation : average grain size = f(p) shows the existence of a unique sintering trajectory for any nitrogen pressure applied. A depressurization cycle optimization revealed that it's possible to obtain another sintering trajectory which translates the capability of materials to continue densification after depressurization without grain growth
QUINTANILHA, MENEZES JOSE EDUARDO. "Methodes analytiques et numeriques pour l'etude des cavites salines profondes. Application au stockage du gaz naturel". Palaiseau, Ecole polytechnique, 1996. http://www.theses.fr/1996EPXX0042.
Texto completoLabidi, Ahmed. "Etude de capteurs de gaz à base d'oxyde de tungstène (WO3) par spectroscopie d'impédance". Aix-Marseille 3, 2006. http://www.theses.fr/2006AIX30025.
Texto completoThe aim of this work is the determination of detection mechanism for WQ3 based sensors by impedance spectroscopy, under reducing (ethanol and acetone) or oxidizing (ozone) gases. This technique is a powerful method for understanding the conduction processes and the solid/gaz interaction mechanisms of these sensors kind. The studied WOa sensitive thin layers were deposited at the laboratory by reactive radio-frequency magnetron sputtering and vacuum evaporation. These techniques permit to prepare homogeneous and polycrystalline thin layers. The morphological properties were studies by atomic force microscopy (AFM). The impedance investigation showed that the sensors interaction with ozone and organic vapors depends on the W03 sensitive layer morphology in particular of their density of grain boundaries. We have also analyzed by impedance spectroscopy the response under ozone and ethanol of W03 based sensors wherein the film surface was modified by gold (Au) or palladium (Pd) metal additive. The results of these studies showed that the Au addition improves slightly the sensitivity of the sensors toward ethanol, for the films of WO3 obtained by sputtering or evaporation. Under ozone, the Au addition seems to be able to improve the sensitivity of WC3 sensors film prepared by evaporation. For instance, the sensors became practically insensitive toward the two used gases when Pd is added. The results of this work make it possible to determine the principal morphological parameters to take into accounts for the improvement of the WO3 based sensors responses
Patois, Tilia. "Elaboration et caractérisation de polymères conducteurs electrosynthétisés : Application à la détections de gaz polluants". Besançon, 2012. http://www.theses.fr/2012BESA2030.
Texto completoThickness, hydrophobicity, semi-crystallinity, electrical conductivity, conduction mode, morphology, or roughness are properties that can be tuned and controlled by varying electrochemical conditions (such as electrodposition potential, nature of the electrolyte salt or salt monomer concentration used during the electrodeposition of polypyrrole. [. . . ] The synthesis of hybrid materials based on polypyrrole and sulfonated cobalt phthalocyanine was also performed. These new materials, introduced into the gaz sensor notably improved the sensitivity of the sensors to ammonia and were proved to be more efficient than sensitive layers only composed by a polypyrrole film
Chalabi, Habib. "Conception et réalisation d'une plate-forme multi-capteur de gaz conductimétrique…Vers le nez électronique intégré". Aix-Marseille 3, 2007. http://www.theses.fr/2007AIX30064.
Texto completoSemiconducting oxide gas sensors often bases on structures unstable over time and presents always low gas selectivity. Thus this work describes the development of new generation gas microsensors. The different elements of the device have been studied and improved. In particular, a new micro-hotplate with platinum resistance could be achieved by using a numerical approach based on the finite element method. Good control of technological processes has enabled the development of a multi-sensors technology involving four cells on one chip. A WO3 sensitive layer was able to be integrated into this system and electrical and thermographic characterizations of devices have been enabled to validate functioning and good stability of structures. Preliminary tests in controlled gaseous atmosphere have provided good overall performances in term of sensibility and selectivity. This work is encouraging first stage for electronic nose realisation
Billi, Elena. "Développement de capteurs de gaz électro-chimiques pour le contrôle de la pollution de l'air". Lyon, INSA, 2003. http://theses.insa-lyon.fr/publication/2003ISAL0001/these.pdf.
Texto completoTwo ceramic gas sensors, developed by screen-printing technique, are considered. The first is able to detect CO and Nox concentrations in combustion processes and, to increase its durability, a alpha-alumina protective layer was deposited by screen-printing on the sensor sensing element. The alpha-alumina screen-printable ink was realised with a new formulation to minimise the possible interactions between the layers. The other sensor is a device for CO₂ monitoring in urban areas: the sensing materials, Nasicon and Yttria stabilised zirconia, are deposited as overlapped films. After the thermal treatment this sensor doesn't work because of an interface reaction between the layers. This reaction is studied by SEM and TEM and is not avoidable. Then the sensor is realised by substitution the Nisicon film with a beta-alumina one and it shows good sensibility and stability
Daher, Carlos. "Etude et réalisation de capteurs térahertz à base de nanocanaux asymétriques de gaz d’électrons bidimensionnel". Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS121/document.
Texto completoTerahertz frequency domain (THz, 1 THz = 10^12 Hz) is part of the electromagnetic spectrum that is not yet under control. It does have physical properties that concern very different fields such as spectroscopy, telecommunications, imaging, security...The project goal of this thesis was to study and to realize a new type of THz sensor based on asymmetrical nanochannels of two-dimensional electron gas (2DEG) also called Self‐Switching‐Devices (SSDs). These new devices have a non-linear I-V characteristics allowing them to operate as quadratic detectors like conventional Schottky diodes.SSDs manufactured by creating – into a heterojunction containing a two-dimensional electron gas — two symmetrical L-shaped insulating trenches arranged in head to tail, present high electron mobility that allows them to work at very high frequencies. Contacts are simply made by metal deposit on each side of the device and the completely planar architecture allows easy downscaling and parallelization. This is a great contrast with the traditional diode, and obviously leads to a significant reduction of the production cost. Moreover, the extremely simple architecture enables a very low parasitic capacitance and therefore a very high operation speed. From Monte Carlo simulations, the device is expected to operate also in the THz frequency range, in which very broad ranges of applications have been visualized.We have developed two experimental benches and demonstrated, in a quasi-optical configuration, free space and at room temperature that gallium nitride (GaN) based SSDs act as rectifying direct detectors and heterodyne detectors up to 0.69 THz. Responsivities of 2 V/W and 0.3 V/W with bandwidths greater than 40 GHz and 13 GHz were obtained in the 0.30 and 0.69 THz ranges, respectively. The characterization of the SSDs as mixers didn't show any deviation from linearity between the THz carrier (RF) input power and the power of the intermediate frequency (IF) signal output. Monte Carlo simulations, used to estimate nano-device intrinsic conversion losses of 27 dB at 0.69 THz, have confirmed these results. As a consequence, the practical implementation of SSDs as mixers of high-power sub-millimetre waves seems feasible. Moreover recent studies of similar GaN-based nanodevices, have demonstrated their possibilities to act as Gunn oscillators that could be active elements in THz emitters. Therefore, the good performances of GaN nanochannels demonstrated in this thesis allow not only the easy integration of antennas for a better free space coupling but also (i) a flexibility in the design of an optimum thermal dissipation and reduction of parasitic effects, and (ii) the possibility to develop a fully integrated emitter/detector submillimeter-wave system working at room temperature
Richard, Marc-André. "Adsorption de gaz sur les matériaux microporeux, modélisation, thermodynamique et applications". Thèse, Université du Québec à Trois-Rivières, 2009. http://depot-e.uqtr.ca/1158/1/030105458.pdf.
Texto completoNgo, Kieu An. "Etude d'un système multiplicateur pour la détection sélective des gaz". Aix-Marseille 3, 2006. http://www.theses.fr/2006AIX30018.
Texto completoChemical sensors based on metallic oxide undergo a significant lack of selectivity to gases. To overcome this problem, we proposed a solution based on the electronic nose approach, i. E. The combination of several sensors with appropriate pattern recognition methods. A semi-automatic test bench including a matrix composed of several commercial gas sensors was carried out. We used two sensor heating procedures (isotherm mode and temperature modulation mode). Principal component analysis and artificial neural networks were used as pattern recognition techniques. The first heating procedure, applied to a six-sensor array, allowed to classify and to identify five toxic gases (CO, NH3, H2S, C2H2 and NO, each gas concentration was 100 ppm). Moreover, the quantification of gas in binary mixtures was satisfactory, with a RMSEPr value of about 10 %. The second heating procedure, applied to a four-sensor array, allowed to identify three reducing gases (CO, C2H2, and H2S) with concentrations varying from 25 ppm to 100 ppm
Wannebroucq, Amélie. "Synthèse de matériaux moléculaires et héterojonctions, de l'intérêt des matériaux ambipolaires dans les capteurs de gaz conductimétriques". Thesis, Bourgogne Franche-Comté, 2017. http://www.theses.fr/2017UBFCK047/document.
Texto completoThe molecular semiconductors have enabled the production of electronic devices such as field effect transistors, diodes and other heterojunctions. The ambipolar materials, capable of carrying both positive charges and negative, result in devices with special properties. The purpose of this thesis is to synthesize new ambipolar materials develop original electronic devices, especially for applications in the field of gas sensors. We are interested in molecules capable to lead to thin films with low temperature techniques known as solution processing, particularly metallo-phthalocyanines
Nasr, Gihane. "Matériaux polymères dynamiques pour membranes adaptatives". Montpellier 2, 2007. http://www.theses.fr/2007MON20231.
Texto completoBrunet, Jérôme. "Elaboration, étude et optimisation de capteurs de gaz à phtalocyanines pour la pollution atmosphérique". Clermont-Ferrand 2, 2003. http://www.theses.fr/2003CLF21455.
Texto completoBrunol, Emmanuelle. "Généralisation des mécanismes de détection de composés de type organophosphonate en surface de capteurs de gaz à base de dioxyde d'étain". Besançon, 2005. http://www.theses.fr/2005BESA2076.
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