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Corre, Thibaut. "Fluoration catalytique du chlorure de trichloroacétyle en présence de fluorure d'hydrogène et de catalyseurs à base d'oxyde de chrome". Poitiers, 2010. http://www.theses.fr/2010POIT2351.
Pełny tekst źródłaThe fluorination of trichloroacetyl chloride and perchloroethylene was studied in gas phase, at at temperature ranging from 300°C to 360°C in the presence of unsupported and partially fluorinated alumina supported chromium oxide based catalysts. The modifications of the chromium oxide based catalysts with a second metal such as zinc, nickel or magnesium has been investigated in order to identify the active sites to favor the main fluorination reaction and decrease the secondary reactions such as decarbonylation reaction of trichloroacetyl chloride and dehydrohalogenation reaction of perchloroethyene. Only a mixed chromium-zinc oxide based catalyst with a molar ratio Zn/(Zn+Cr) equal to 0. 2 allows to minimize the secondary reactions. However, for the transformation of trichloroacetyl chloride, it also corresponds to a decrease of the selectivity towards the totally fluorinated intermediate. Indeed, the presence of zinc in a chromium oxide based catalyst leads to a decrease of the Lewis acid strength (characterized by pyridine adsorption followed by infrared) of the unsaturated metallic species which are the active sites. These results demonstrate clearly that the catalytic sites involved for the fluorination and the decarbonylation reactions of trichloroacetyl chloride are the same
Bose, Sourav. "Development and Study of Earth-Abundant Oxide Based Thin Films for Solar Cells by Ultrasonic Spray Pyrolysis : From Unbeknownst to Erudite Processes". Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0131.
Pełny tekst źródłaThe results on elaboration of environmentally compatible, earth-abundant metal oxide thin films using the technique of ultrasonic spray pyrolysis are presented. Three essential materials are developed for the purpose of realization of an “all-oxide” solar cell device: Zinc oxide (ZnO) as window layer; zinc magnesium oxide (ZnMgO) as a buffer layer and cuprous oxide (Cu2O) used as an absorber layer. Comprehensive design of experiments was set up for the elaboration of each material. Highly transparent ZnO was elaborated in wide range of thickness with high crystalline qualities with specific elaboration temperature with a precise control on the concentration of the precursors. ZnMgO was elaborated by varying the molar compositions of the magnesium precursor in the precursor solution. Up to nearly 30 % of Mg, the ZnMgO films exhibited single crystalline phase with high transparencies. High-absorbing Cu 2 O elaboration was optimized with effective control on the elaboration temperature and the concentration of a new reducing agent (D-sorbitol). To expand the horizon of efficiency of our elaboration process, two more materials, ZnAlO and ZnAlMgO, were elaborated. It was found that the optical, electrical, and structural properties of the ZnAlO films could be modulated for use in “all-oxide” solar cells by varying magnesium (up to 7 mol%) and aluminum (up to 2 %). The bandgap energies and the electrical properties of the films were modulated with the co-doping so that they can be integrated as window/top-contact/buffer layers in “all-oxide” solar cells. Additionally, simulations performed using Silvaco Atlas® and Solis also demonstrates the applicability of these films for “all-oxide” solar cells
Cahoreau, Amélie. "Trous d' électrons dans des oxydes de type cuprate supraconducteur. Etude cristallochimique d'une nouvelle famille d' oxyhalogènure de tellure et d' alcalinoterreux A3Te2O6X2 (A=Sr, Ba et X=Cl, Br". Phd thesis, Université Sciences et Technologies - Bordeaux I, 1996. http://tel.archives-ouvertes.fr/tel-00150529.
Pełny tekst źródłaDiler, Erwan. "Étude de la corrosion atmosphérique du zinc et zinc-magnésium, en milieu marin". Phd thesis, Université de Bretagne occidentale - Brest, 2012. http://tel.archives-ouvertes.fr/tel-00725313.
Pełny tekst źródłaGeneste, Grégory. "Mécanismes élémentaires de la croissance oxyde sur oxyde : étude ab initio et semi-empirique de MgO/MgO(001)". Toulouse 3, 2003. http://www.theses.fr/2003TOU30156.
Pełny tekst źródłaSuwanboon, Sumetha. "Synthèse et caractérisation de ZnO nanométrique par la méthode chimie douce". Montpellier 2, 2006. http://www.theses.fr/2006MON20034.
Pełny tekst źródłaWe have synthesized nanostructured ZnO materials by various ways of soft chemistry techniques, i. E. Sol-gel and pyrosol methods. This research has consisted to study and develop the experiment parameters which influence the structural properties of nanostructured ZnO such as nature of precursor, complexing agent or stabilizer, precursor and dopant concentration. The thermal parameters such as reaction temperature and heat treatment temperature have been optimized as well. The ZnO materials containing of chromium and aluminium have also been studied. The undoped ZnO thin films prepared by dip coating on glass substrate give, in the best case, the approximate size 40 nm. In case of doped ZnO material, ZnO:Al, 10 at. % Al, the sizes reach approximate 5 nm. The ZnO thin films are prepared by pyrosol method giving the smallest size of undoped ZnO about 70 nm and ZnO:Al, 5 at. % Al about 90 nm. Lastly, the ZnO nanoparticles are prepared by precipitation giving the smallest size about 10 nm. The nanocrystalline CrxZn1-xO powders where x is 0. 05, 0. 10 and 0. 15, have exhibited a weak ferromagnetic behavior with Curie temperature of 0. 6, 2. 6 and 7. 1 K, respectively
Blidi, Abdelkader. "Frittage et réactivité des solides : réexamen des modèles cinétiques de l'étape initiale du frittage et des lois de variation isotherme de surface". Dijon, 1988. http://www.theses.fr/1988DIJOS015.
Pełny tekst źródłaSerrano, Servin Manuel. "Etude du comportement électrique et thermique de parafoudres à oxyde de zinc". Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb376185613.
Pełny tekst źródłaHan, Zhitao. "Intégration de nanofils de ZnO dans des dispositifs microfluidiques pour lesétudes photocatalytiques et photovoltaïques". Paris 6, 2013. http://www.theses.fr/2013PA066424.
Pełny tekst źródłaCe travail de thèse vise à intégrer des nanofils de ZnO dans des dispositifs microfluidiques pour les études photocatalytiques et photovoltaïques. Tout d'abord, la méthode de croissance hydrothermale a été améliorée par dépôt direct d’une couche germe de ZnO de haute qualitéun en utilisant un procédé sol-gel et une technique de revêtement par centrifugation. Ensuite, cette couche de ZnO semencée a été lithographiée pour définir des zones de croissance. Comme résultats, les matrices de nanofils de ZnO bien alignées ont été obtenues sans fusion au pied des nanofils. Deuxièmement, des nanofils de ZnO à grande surface ont été intégrés dans les réacteurs microfluidiques, permettant une photocatalyse stable et à haut rendement. Troisièmement, les nanofils de ZnO intégrés ont été utilisés pour des essais sur les cellulaires solaires à colorant (DSSC), montrant une dépendance claire sur les conditions de croissance de nanofils de ZnO, mais peu d’effet sur le débit d'électrolyte microfluidique. Enfin, la synthèse hydrothermale a été appliquée pour obtenir des nanofibres de ZnO par électrofilage avec ou sans dopage de palladium. En comparant aux nanofibres de ZnO purs, les nanofibres de ZnO dopées de Pb ont montré une efficacité de photodégradation du bleu de méthylène améliorée
Fichou, Denis. "L'interface oxyde de zinc/électrolyte : étude des processus primaires". Paris 6, 1986. http://www.theses.fr/1986PA066259.
Pełny tekst źródłaSerrano, Servin Manuel. "Etude du comportement électrique et thermique de parafoudres à ZnO". Ecully, Ecole centrale de Lyon, 1988. http://www.theses.fr/1988ECDL0022.
Pełny tekst źródłaMoustaghfir, Abdellah. "Elaboration et caractérisation de couches d'oxyde de zinc". Clermont-Ferrand 2, 2004. https://tel.archives-ouvertes.fr/tel-00012168.
Pełny tekst źródłaSajti, Csaba Lảszlỏ. "Synthèse de nano-agrégats et de matériaux nanohybrides à base d'oxyde de zinc par ablation laser femtoseconde en phase liquide : étude de l'élaboration et des propriétés optiques". Aix-Marseille 2, 2007. http://theses.univ-amu.fr.lama.univ-amu.fr/2007AIX22064.pdf.
Pełny tekst źródłaThroughout this thesis, we have developed a method to synthesize ZnO nanoclusters and dye-grafted ZnO nanohybrids using femtosecond laser ablation in liquid environment. The average particle size, the size distribution and the optical properties of ejected species are controlled by the properties of the surrounding liquid, the laser parameters and concentration of the additives. Photoluminescence measurements revealed synthesized ZnO nanoparticles with very high optical quality. For nanoclusters ablated with mild laser fluence, we observed clear modifications in optical properties due to quantum confinement effects, resulting from size-reduced nanoparticles. ZnO nanohybrids were synthesized via two different techniques. ZnO nanoparticles are crystallized as spheres, whereas nanohybrids showed well-developed faceted surfaces indicating the change in growth condition owing to the presence of grafted chromophores on the nanoparticle surface. When exciting the ZnO core of the nanohybrids we observed efficient excitation exchange from the nanoparticles toward the attached dye molecules. The same effect was observed by two-photon excitation in the near IR region proving that the nanoparticles contribute to the grafted dye emission. Rapid exctitation exchange process was confirmed from the ZnO core material toward the grafted chromophores by time-correlated single photon fluorescence spectroscopy
Liu, Jun. "Etude et exploration de nanofibres obtenues par électrospinning : microstructuration, croissance dirigée, et segmentation par ultrasons". Paris 6, 2012. http://www.theses.fr/2012PA066241.
Pełny tekst źródłaBinesti, Didier. "Les varistances à base d'oxyde de zinc : épreuves de vieillissement et dégradation". Bordeaux 1, 1985. http://www.theses.fr/1985BOR10587.
Pełny tekst źródłaGuérin, Victoire-Marie. "Synthèse et optimisation de couches d'oxyde de zinc nanostructurées pour une utilisation en cellule solaire à colorant". Paris 6, 2013. http://www.theses.fr/2013PA066044.
Pełny tekst źródłaThe following thesis describes the research we have undertaken on zinc oxide-based Dye-Sensitized Solar Cells (DSSC). This work followed two directions. First, we have developed a quick preparation process for semi-conductor layers. This let us set up our DSSC preparation and characterization processes. We then used these methods to undertake systematic studies in order to optimize some parameters of the solar cell preparation. Second, we have researched the electrodeposition synthesis of semi-conductor layers tailored to the needs of DSSCs. The main criteria to look for are a high specific surface area and a good electron conduction inside the layer. We then turned to the preparation of hierarchical structures based on ZnO nanowires. Without using any structure directing agent during the deposition, we have obtained morphologies on two scales, with a second nanocristalline phase. Other hierarchical structures are also described. Among them, some are based on nanowires organized in tri-dimensional “urchin” networks
Ozerov, Igor. "Synthèse de nano-agrégats d'oxyde de zinc et dépôt de films nanocristallins par ablation laser en vue d'applications optoélectroniques". Aix-Marseille 2, 2004. http://www.theses.fr/2004AIX22058.
Pełny tekst źródłaFons-Dupuy, Colette. "Influence des éléments métalliques zinc et magnésium sur les paramètres rhéologiques et microrhéologiques du sang : implication de ces paramètres hémorhéologiques dans les pathologies artérielles athéromateuses (Doctorat : Sciences physico-chimiques et technologie pharmaceutiques)". Montpellier 1, 1997. http://www.theses.fr/1997MON13528.
Pełny tekst źródłaTanouti, Boumediene. "Contribution à l'étude des varistances à l'oxyde de zinc : rôle des oxydes additifs et du processus d'élaboration sur les caractéristique électriques". Bordeaux 1, 1985. http://www.theses.fr/1985BOR10568.
Pełny tekst źródłaElias, Jamil Lévy-Clément Claude. "Réseaux de nanofils et de nanotubes d'oxyde de zinc de dimensions contrôlées obtenus par voie électrochimique application aux cellules solaires nanostructurées /". S. l. : S. n, 2008. http://doxa.scd.univ-paris12.fr:80/theses/th0494568.pdf.
Pełny tekst źródłaDumergue, Mathieu. "Luminescence ultraviolette et dynamiques excitoniques dans l’oxyde de zinc massif et nano-structuré". Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0032/document.
Pełny tekst źródłaThis thesis presents the work carried out at CELIA about ultraviolet luminescence and exciton dynamics in massive and nano-structured zinc oxide (ZnO). Measurements were carried out under controlled experimental conditions (temperature, excitation fluence), according to different excitation photon energies.We measured emission spectra under UV photon excitation (4.66 eV), and 3 IR photons (1.55 eV), and suggested a sequential exciton formation mechanism (with simulations), especially for DX excitons. We found a nanosecond lifetime for DX in both cases, in disagreement with most of the studies published in the literature. Relaxation dynamics of free and bound excitons are linked by the FX trapping process on donor defect and the DX thermal detrapping.Under VUV excitation (20-50 eV), surface effects and strong local excitation density greatly accelerate the relaxation of excitons. Under X excitation (1 keV), good conditions for the formation of DX seems to be close under excitation at 1.55 and 950 eV.The presence of core 2p band of zinc modifies the relaxation dynamics of excitons by the multiplication of local high density excitations zones and the change of the elementary excitations distribution. We have also conducted measurements on nano-particles. The significant surface effects induced by the small size of these system lead to a sharp acceleration of kinetics, masking the intrinsic exciton relaxation process
Zhang, Le. "Fixation du phosphate et des ions (Zn²+, Mg²+) sur la phosphatase alcaline de mammifère et rôle de son activité phosphodiestérase dans le processus de minéralisation". Lyon 1, 2005. http://www.theses.fr/2005LYO10120.
Pełny tekst źródłaPages, Carole. "Etude du comportement en solution de nanoparticules d'oxyde de zinc préparées par voie organométallique : étude du milieu réactionnel, chimie de surface et conditions d'organisation". Toulouse 3, 2007. http://thesesups.ups-tlse.fr/137/.
Pełny tekst źródłaIn this PHD, we interested in the comportement nanoparticules which prepared by an organometallic method, in solution. Different techniques of characterisation were used (RMN, RMN Dosy, NOE. . . )
Tosoni, Olivier. "Conception, élaboration et intégration d'électrodes transparentes optimisées pour l'extraction des charges dans des dispositifs photovoltaïques". Phd thesis, Université de Grenoble, 2013. http://tel.archives-ouvertes.fr/tel-00955867.
Pełny tekst źródłaChafik, Tarik. "Réactivité des espèces formées par l'adsorption des réactifs et des produits de la synthèse du méthanol sur des aérogels de zircone et de ZnO supporté sur zircone (ZrO2)". Lyon 1, 1993. http://www.theses.fr/1993LYO10253.
Pełny tekst źródłaDoumandji, Zahra. "Identification de marqueurs d’exposition et d’effets de nanoparticules métalliques sur modèle in vitro". Thesis, Université de Lorraine, 2019. http://www.theses.fr/2019LORR0067.
Pełny tekst źródłaAs a consequence of the extension of the use of nanoparticles in different industrial sectors, the number of potentially exposed workers continues to grow, without fully knowing the toxicological properties of these materials. Since nanoparticles can be aerosolized in the occupational atmosphere, inhalation is the major occupational exposure route. For this reason, risk assessment of exposure to nanomaterials requires toxicology studies to be conducted on cellular models of the airways. In this manuscript, the cellular and molecular responses of rat alveolar macrophages (NR8383) exposed to metallic oxide nanoparticles: ZnO, ZnFe2O4, NiZnFe2O4, Fe2O3, TiO2-NM105 and TiO2-NRCWE001, were studied, combining conventional toxicological analyzes (characterization of nanoparticles by transmission electron microscopy and dynamic light scattering, evaluation of cytotoxicity by WST-1 assays and LDH release); and high throughput molecular screening (transcriptomic and proteomic analyzes). NR8383 cells were exposed to the ZnO, ZnFe2O4, NiZnFe2O4, Fe2O3, TiO2-NM105 and TiO2-NRCWE001 nanoparticles for 24 h which allowed for the determination of a sub-toxic dose for each nanoparticle to which the macrophages were exposed for molecular analysis. Four hours after exposure NR8383 to nanoparticles, many genes and proteins were differentially expressed. Oxidative stress was the adverse biological response following exposure of cells to nanoparticles composed of zinc. In contrast, inflammation was the main activated pathway in cells exposed to the anatase and rutile form of TiO2 nanoparticles. In conclusion, this study exposes the "biological fingerprints" of the two groups of nanoparticles of interest. Finally, our study, combined with previous literature studies, could also be beneficial in validating biomarkers of exposure and effects of nanomaterials suggested in order to predict adverse biological effects
Martini, Cyril. "Nanohybrides ZnO-Distrylbithiophènes : synthèse, propriétés structurales et dispositifs électroniques". Aix-Marseille 2, 2008. http://www.theses.fr/2008AIX22089.
Pełny tekst źródłaThe design of flexible electronics devices at low cost is a challenge of particular interest for future electronics. By combining at nanometric scale both organic and inorganic materials, we can avoid the hard conditions needed for inrganic materials and use solution processes [. . . ]
Le, Rouzic Mathieu. "Étude des propriétés physico-chimiques et mécaniques des matériaux cimentaires à base d’oxyde de magnésium". Thesis, Paris Est, 2014. http://www.theses.fr/2014PEST1082/document.
Pełny tekst źródłaMagnesium phosphate cements are the most representative cements of the activated-by-acid cements family. Despite the fact that they are known since the early 20th century, their use in civil engineering is fairly limited. These materials are used for road repairs where the fast compressive strength development is an advantage. Recently they have also been used in wastes stabilization/solidification (S/S), especially with wastes incompatible with Portland cement. The challenges of the use of these cements are related to the nature of their formation reaction: fast, very exothermic, with a very short setting time (only a few minutes).The bonding phase, k-struvite (MgKPO4.6H2O), is obtained from magnesium oxide mixed in water with monopotassium phosphate (KH2PO4).MgO + KH2PO4 + 5H2O MgKPO4.6H2OThe setting mechanisms are still poorly known and various theories, involving or not secondary product formation, have been suggested. Our researches have aimed to understand the setting mechanisms, as well as the influence of the formulation parameters on the properties of the magnesium phosphate cement. Results show that the formation of k-struvite involved a precipitation-dissolution reaction of an intermediate product, the newberyite (MgHPO4.3H2O). Formation reactions of these two products are controlled by the supersaturation rate and the pH of the solution. The study highlights the strong effect of water on the properties of fresh cement paste. With a low mass ratio e/c in comparison of Portland cement (ratio e/c between 0,1 and 0,25), a slight modification of the ratio (0,02) leads to a segregation and a surface heterogeneity of the cement paste. Among the formulation parameters, the molar ratio MgO/KH2PO4 (Mg/P) seems the most important parameter. Indeed, it impacts most of the properties of the magnesium phosphate cement (compressive strength, setting time, reaction heat, paste fluidity …). Low Mg/P ratios lead to poor water resistance, to crystals formation inside the microstructure that can be seen on the surface of the sample (an efflorescence appearance), and to important swelling of the paste, leading to the cracking of the samples. After the parametric study, a magnesium phosphate cement paste has been defined. Dimensional changes and chemical shrinkage measurement were conducted to understand the mechanisms involved in this swelling phenomenon. In support, microstructural analyses (SEM, XRD, TGA) and leaching tests complete the experimental campaign. The results confirm the influence of a low Mg/P ratio on cement swelling and water resistance. Finally, a study on various additions to the paste has been conducted, with the purpose of improving the cement paste performances. It shows that the addition of an inert filler (siliceous sand or fly ashes) has a retarding effect and reduced the reaction heat
Talagrand, Clément. "Transistor en couches minces avec canal en oxyde d’indium de gallium et de zinc : matériaux, procédés, dispositifs". Thesis, Saint-Etienne, EMSE, 2015. http://www.theses.fr/2015EMSE0797/document.
Pełny tekst źródłaIn order to carry out electronics functions on flexible substrate, thin film transistor is essential. The aim of this thesis is to increase knowledge on this device.State of art of IGZO TFT is summarized in chapter 1. This part presents thin film transistor and justify the choice of IGZO as the semiconductor material. Then, properties of this amorphous oxide semiconductor are discussed. Finally, this chapter presents the results obtained in the literature for IGZO based thin film transistor.Chapter 2 establishes a link between IGZO properties and sputtering deposition. Films are studied by spectroscopic ellipsometry. Experiments show variations in optical properties due to deposition time, oxygen content and position on the wafer. Resistivity measurements are carried out to understand more deeply the causes of these variations.Chapter 3 develops a complete process to achieve TFT on flexible substrate. The choice of different materials and processes is discussed. The performances of the TFT are investigated versus the annealing time and characterized under mechanical stress. Mobility up to 10 cm2.V-1.s-1 can be achieved after an annealing at 300°C during 1h30. Mechanical stresses show a degradation of the transistor induced by cracks in the oxide layer.Chapter 4 focuses on IGZO's deposition by inkjet printing. An ink is formulated using metallic salts and a solvents mixture. The parameters of the printing system are also optimized. To compare the different techniques of deposition, printed IGZO TFTs are characterized and compared with the one fabricated with the standard PVD deposition technique. Mobility is relatively lower and equals 0.4 cm2.V-1.s-1
Poize, Guillaume. "Élaboration et caractérisation de dispositifs photovoltaïques hybrides à base de nanoparticules de ZnO : vers un contrôle de la nanostructuration p-n de la couche photovoltaïque". Aix-Marseille 2, 2009. http://theses.univ-amu.fr.lama.univ-amu.fr/2009AIX22104.pdf.
Pełny tekst źródłaFirst, nanoparticles with different shape were simply mixed with the polymer poly-(3-hexylthiophene) (P3HT) in order to realize an interpenetrating hybrid p-n network. Second, P3HT was replaced by a shell of organic semiconductor created by grafting an organic molecule to the surface of the ZnO nanorods. Studies of the photovoltaic properties of the ZnO-P3HT system have shown that the morphology of the photoactive layer is very sensitive to the methanol concentration initially present during the ZnO synthesis. The highest device efficiency of 0. 8% was obtained using nanodots with 4 mm of diameter in air with external quantum efficiency around 48% at the maximum of absorption of P3HT. Detailed analyses have shown that using ZnO nanorods improve the transport of electrons as well as the cristallinity of P3HT. Furthermore, we found that the device stability in air is markedly superior for devices using nanorods. Solar cells were fabricated to test the nanoscale control of the p-n junction morphology possible through the use of the coaxial p-n architecture. These nanoscale controls were obtained by creating a monolayer of grafted organic molecules directly to the surface of the ZnO nanorods and let to define the p-n interface at the level of one nanorod. Examples of these interpenetration selfassembled p-n junctions have demonstrated efficiencies of 0. 1% in air with a maximum external quantum efficiency of 15%
Marzouki, Ali. "Croissance et caractérisation optique et électrique de films de ZnO dopés azote et antimoine". Versailles-St Quentin en Yvelines, 2011. http://www.theses.fr/2011VERS0005.
Pełny tekst źródła@ZnO thin layers and nanowires were grown by MOCVD. The samples were characterized by SIMS, MEB, TEM, RX, Raman, PL, Hall effect, I(V) and C(V). These studies showed the n-type conduction nitrogen-doped layers even after thermal treatments. N-doped ZnO with two new precursor tributylamine and ammonia revealed that nitrogen incorporation is accompanied of the presence of donor-acceptor pair (DAP) observed by PL and of local Raman nitrogen modes (LVM). The DAP band and LVM modes became more intense when ZnO is doped with antimony which the concentration is high about 1020 at. Cm-3. We have successfully fabricated ZnO:Sb/ZnO diode structures showing PN junction and high green electroluminescence spectrum
Alvarez-Gutierrez, Alejandro. "Etude statistique de la corrosion atmosphérique et de la corrosion par piqûres de l'alliage d'aluminium 7020". Toulouse, INPT, 1994. http://www.theses.fr/1994INPT006G.
Pełny tekst źródłaPasquet, Julia. "Les nouveaux conservateurs minéraux : application à la conservation antimicrobienne de différentes formulations et étude du mécanisme antimicrobien : étude appliquée à l’oxyde de zinc". Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10145.
Pełny tekst źródłaThe microbiological quality of a cosmetic product should be preserved during its whole shelf-life notably thanks to the addition of antimicrobial preservatives. Nevertheless, commonly used organic preservatives are particularly criticized since a few years because they are suspected of side effects. In order to propose alternatives to these substances, the antimicrobial properties of zinc oxide (ZnO) were studied. The antimicrobial efficacy of these inorganic particles was evaluated on the five microorganisms of interest for the cosmetic industry (E. coli, S. aureus, P. aeruginosa, C. albicans and A. brasiliensis). Microbiological tests were designed in agar medium and liquid broth to evaluate the sensitivity of each microbial strain to ZnO. The efficacy of these powders was evaluated in various dermopharmaceutical formulations via Challenge Tests. Some specific studies dedicated to improve the understanding of antimicrobial mechanisms of ZnO were carried out: (i) particles dissolution generating zinc cations, (ii) photochemical generation of free radicals (iii) direct contact between particles and microbial cells. Coupled with additional studies designed to refine structure/activity relationships, this work was performed in order to optimize the antimicrobial potential of these powders for the present application. All these studies demonstrated that ZnO enabled the preservation of the microbiological quality of various cosmetic products (emulsions and powders). The bactericidal, levuricidal and fongistatic activities of ZnO were dependent of its concentration and confer to the products the ability to comply with the demands in term of preservation. The inorganic powders of ZnO appear as suitable alternatives to organic preservatives
Joo, Gi-Tae. "Nouvelles phases ferroélectriques non stoechiométriques de type perovskite ou LiTaO3". Phd thesis, Université Sciences et Technologies - Bordeaux I, 1986. http://tel.archives-ouvertes.fr/tel-00203505.
Pełny tekst źródłaHaneche, Nadia. "Etudes optiques de ZnO et des solutions solides Zn[1-x]MgxO et Zn[1-x]CdxO : conception de nanostructures et dopage de type p". Versailles-St Quentin en Yvelines, 2011. http://www.theses.fr/2011VERS0037.
Pełny tekst źródłaZinc oxide (ZnO) is a wide band gap semiconductor, and receives actually a considerable attention for the realization of optoelectronics devices. The current problems for these applications are related to the growth of quantum well structures, but especially to the successful of the p-type doping of ZnO. From this point of view, we studied the optical properties of layers and nanowires prepared by MOCVD using mainly the photoluminescence spectroscopy (PL). MgxZN1-xO and the CdxZn1-xO alloys show a very good incorporation of Mg and Cd. ZnO/MgXZn1-XO quantum well heterostructures on polar, and non-polar orientations (without an internal electric field) are obtained with a good structural and optical quality. Regarding to the p-type doping of ZnO, nitrogen doping seems to be more efficient with the NH3 precursor. The antimony doped layers are heavily doped. Moreover, it seems that two types of acceptors are observed into the layers made on C-oriented ZnO and R-sapphire substrates
Garnier, Jérôme. "Elaboration de couches minces d’oxydes transparents et conducteurs par spray cvd assiste par radiation infrarouge pour applications photovoltaÏques". Paris, ENSAM, 2009. http://www.theses.fr/2009ENAM0030.
Pełny tekst źródłaMaterials like metallic oxides are both properties of electrical conductivity and good transparency in the visible range. They are called "Transparent Conductive Oxides", TCO. Nowadays, the most used of this material is the indium oxide doped with tin (ITO). Indium is scarce and expensive since the huge fiat screen industries demand on ITO, his priee is thus increasing a lot. Research is looking for a challenger like tin oxide or zinc oxide which are promising materials. Different techniques can be used to deposit such materials in thin films. We chose the method called Spray-CVD because association of good quality deposition from CVD reaction and facility to handle precursors by spray is advantageous. Thus, this technique is simple and economic. The special feature of this deposition method is used infrared lamps as heating mode. Association of Spray-CVD technique and infrared heating is unique as far as we know. We called this entire system: IRASCVD (InfraRed Assisted Spray Chemical Vapour Deposition). Two strategies are developed to deposit competitive TCO thin films with our technique. The first one consists in building an experimental reactor of Spray-CVD in our laboratory. Fluorine doped and undoped tin oxide thin films have been studied and parameters of IRASCVD reactor have been optimized. These films have been used as transparent electrodes for organic solar cells. This allows us to validate the technique of TCO deposition. The second strategy consists in using a R&D reactor based on the same principle. We deposited aluminum doped and undoped zinc oxide in this reactor. We focused our work on infrared influence on thin films properties. A comparison with films deposited with classical heating such as hot plate has been done. This study highlights infrared impact on TCO thin films
Choron, Damien. "Elaboration et caractérisation de varistances à fort champ de seuil à base d’oxyde de zinc". Caen, 2015. http://www.theses.fr/2015CAEN2069.
Pełny tekst źródłaA varistor is a variable resistor: its resistivity varies according to applied electric field. This type of component is generally used in surge suppressor systems. This work aims to improve knowledge on a high-field varistor elaboration-process by chemical route and powder metallurgy. First, the influence of dopants’ concentration and ripening durations after precipitation on powders’ physico-chemical properties were investigated. The synthesised powders’ characteristics were not affected by these process modifications. The sintering mechanisms were then studied both by the MSC-method and the use of a design of experiments, dealing with three parameters: the heating rate and the dwell temperature and duration. During these studies, the densification of the material was compared with and without sodium, and sintering conditions conducing to the desired properties were established. Used temperatures allowed to retain a small grain size and to obtain a high density and a breakdown field compliant with specifications. Finally, microwave sintering of ceramics was investigated: magnetic-field heating is possible and allows reducing drastically the sintering duration. The obtained densities and grain sizes are similar to those observed in conventional sintering. However, this materials show low electric properties, probably due to the high heating rates used in these experiments
Duvignacq, Carole. "Caractérisation et modélisation numérique des dégradations des peintures blanches en environnement spatial simulé". École nationale supérieure de l'aéronautique et de l'espace (Toulouse ; 1972-2007), 2003. http://www.theses.fr/2003ESAE0014.
Pełny tekst źródłaLippert, Marc. "Elaboration et caractérisation de couches minces piezoélectriques d'oxyde de zinc obtenues par pulvérisation cathodique". Valenciennes, 1999. https://ged.uphf.fr/nuxeo/site/esupversions/6a235e1a-0eaf-4bd6-a862-aafdf1dd7913.
Pełny tekst źródłaThe study focuses on the elaboration and the characterization of thin layers of zinc oxide (ZnO) obtained by a cathodic radiofrequency magnetron sputtering. These layers are analyzed by classic characterization techniques of materials : the diffraction of rays X and the scanning electronic microscope. These thin films present two preferential orientations following the osition in the face of the target and under some conditions of deposit : a layer well textured where the c-axis is perpendicular to the surface of the substrate and a layer that possesses a -axis parallel to the plan of the substrate and this orientation is (110). These films are then analyzed to determine their piezoelectric properties. Two other methods have been developed :a method of measure of the transit time of ultrasound waves generated in the transducer if the layer is piezoelectric. This method permits to determine also its vibration mode. The other ethod is devoted to the direct determination of the electromechanical coupling coefficient by the measure of the electrical impedance of this same transducer. This last method have been ested on transducers using a crystal of lithium niobate (LiNbO3) bonded by indium metallic diffusion and we have permitted to find a coupling coefficient superior to 95% of the theoretical value. Thin layers of ZnO realized, presented the particularity to generate transverse waves , with a coupling coefficient approaching 45% of the theoretical value of the massive material
Balasoiu-Ungureanu, Maria-Camélia. "Synthèse et propriétés de verres à base de P2O5". Grenoble INPG, 2001. http://www.theses.fr/2001INPG0097.
Pełny tekst źródłaEgal, Magali. "Structure et propriétés des solutions et gel de cellulose-NaOH-Eau et leurs matériaux régénérés". Phd thesis, École Nationale Supérieure des Mines de Paris, 2006. http://pastel.archives-ouvertes.fr/pastel-00002229.
Pełny tekst źródłaBadre, Chantal. "Etude de la réactivité de surface par mesure d'angle de contact : influence de la fonctionnalisation et de la structure : applications aux films d'oxyde de zinc électrodéposés". Paris 6, 2007. https://pastel.archives-ouvertes.fr/pastel-00004902.
Pełny tekst źródłaIn this work, we studied the surface reactivity by contact angle measurements. In our case, we were particularly interested in preparing textured surfaces with different roughness scales. Firstly, we have prepared smooth polyvinylchloride polymers acidified with lauric acid. Then, aerosil balls are added to create some roughness on the polymer. Controlling the roughness and the morphology of these polymers remain a main disadvantage that leaded us to use other materials with easier roughness control like Zinc Oxide (ZnO). Different morphologies were prepared by electrodeposition such like nanorods and nanowires. It is well known that the wettability of ZnO can be modified by applying the bottom-up process. We used self assembled layers (SAMs) of organic molecules like octadecylsilane and fatty acids. We succeeded to prepare superhydrophobic surfaces with the highest contact angle 176° ever obtained on ZnO. The study was extended and ferrocene probe molecules were used
Miedzinski, Rafal. "Etude des effets optiques photo-induits dans les métallo-composites et analyse de leurs caractéristiques surfaciques par microscopie à force atomique". Reims, 2009. http://theses.univ-reims.fr/sciences/2009REIMS038.pdf.
Pełny tekst źródłaPerraud, Igor. "Combustion auto-propagée et mécanosynthèse de ZnS : étude des conversions ZnS <->ZnO et application à la désulfuration des gaz". Thesis, Montpellier 2, 2012. http://www.theses.fr/2012MON20097/document.
Pełny tekst źródłaToday, we have to take care of every technology's environmental effects. The removal of H2S and other sulfur compounds in hot gas enters this ecological aspect in several industrial processes. Zinc oxide is used here as a regenerable sorbent for gas desulfurization. The goal of this work is, the preparation of macroporous ZnO monolithic filters and nanopowders with high sulfur capacity and easily regenerable, and their optimization with the control of their properties. ZnS/NaCl composite materials are first obtained by Self-propagating High temperature Synthesis from mixtures of zinc, sulfur and sodium chloride powders. NaCl is then removed by lixiviation with water. ZnS nanopowders are prepared by mechanical alloying from mixtures of zinc and sulfur. The two materials have different crystalline structure, würtzite type for ZnS filters and sphalerite type for powders, because of the way of synthesis. Then, they are converted into ZnO by thermal treatment under air at 700 °C. Next, the macro- and microstructure transformations of both filter and powders during sulfidation-oxidation cycles are thus considered. Results of all characterizations like X-ray diffraction, scanning electron microscopy and Hg porosimetry show that materials properties are very stable against conversions. Afterwards, ZnO filters and nanopowders are used as adsorbent in desulfurization trials. The sulfur capacity of filters is not so high, 6,4 mg S/g ads and shows that porosity has to be improved. Regarding nanopowders, the sulfur capacity is very high, 272 mg S/g ads, proving that surface area is very important in this application
Heuguet, Romain. "Développement des procédés micro-ondes monomodes à 2450 MHz et 915 MHz pour le frittage de céramiques oxydes". Caen, 2014. http://www.theses.fr/2014CAEN2028.
Pełny tekst źródłaA new microwave single mode cavity was developed to study microwave heating at very high temperature, up to 1500°C. The as developed system, working at 2450 MHz was used to sinter different ceramic oxides. First, zinc oxide material was sintered and the study showed that there is probably a non thermal effect provided by microwave. This non thermal effect was attributed to an electromagnetic pressure. Microwave sintering of pure rutile TiO2 was conducted as well without the use of any susceptor. Almost fully dense TiO2 samples were obtained, and results showed that the microwave process allows lowering the sintering temperature by at least 150°C with respect to the conventional process, and therefore improved dielectric properties were done. Finally, a study on the microwave sintering at high temperature has been done, leading to the development of specific assembly with susceptor, allowing the sintering of alumina. Experimental results and numerical simulations lead us to conclude that the nature of the susceptor (its dielectric properties) highly influences the sintering behavior of alumina. It has been also studied the scaling up of the single mode microwave sintering process, to produce sample, having a diameter greater than 50 mm
Reali, Riccardo. "Modeling creep of lower mantle minerals : bridgmanite and (Mg,Fe)O". Thesis, Lille 1, 2018. http://www.theses.fr/2018LIL1R026/document.
Pełny tekst źródłaThis thesis work addresses the deformation behavior of two major mineral phases of the Earth’s lower mantle: bridgmanite and (Mg, Fe)O. They constitute ~90-95% of the lower mantle and their rheology is of primary importance for a better understanding of mantle convection. The rheological properties of these phases were modeled through the implementation of numerical and analytical techniques, in order to assess their creep behavior (i.e. steady-state deformation under a constant applied stress).The relevant deformation agents driving creep are identified and then modeled at the single crystal scale. In this framework, dislocations are amongst the main carriers of crystal plasticity and the creep behavior of the considered minerals can therefore be assessed by considering dislocation glide and diffusion-driven dislocation climb. (Mg,Fe)O creep is driven by the interplay between glide and climb and in order to model it, a 2.5-dimensional (2.5D) dislocation dynamics (DD) approach has been deployed. 2.5D-DD is a numerical technique which addresses the collective behavior of dislocations at the mesoscale. It is demonstrated that dislocation glide is responsible for the plastic deformation and climb is the rate-limiting mechanism. From the modeled creep strain rates it was possible to estimate viscosity of (Mg,Fe)O at lowermost mantle conditions. As for bridgmanite a pure climb mechanism is proposed, and the creep strain rates were evaluated according to a physics-based analytical creep model. The viscosity of bridgmanite along a geotherm is retrieved and compared with the available observables
Shah, Syed mujtaba. "Nanohybrides d'oxyde de zinc fonctionnalisés par des colorants organiques : synthèse, caractérisation et applications opto-électroniques". Electronic Thesis or Diss., Aix-Marseille 2, 2010. http://www.theses.fr/2010AIX22041.
Pełny tekst źródłaThe research presented in this dissertation deals with the synthesis, properties andoptoelectronic applications of the nanohybrids based on dye and fullerene functionalizedZnO nanoparticles. These molecules being acid functionalized, were co-grafted on thesurface of ZnO nanoparticles. The effect of changing ratio of donor to acceptor, polarityof the solvent and shapes of the nanoparticles on porphyrin/fullerene interaction werestudied. The molecules were found appreciably interacting at a ratio of 1:2 under the cograftedstate on ZnO nanorods. This was indicated by the strong bathochromic shift of thesoret peak of porphyrin and quenching of its fluorescence however, at this ratio chargetransfer complex is not detectable. The complex formation requires both the donors andacceptors to be enough close to each other to undergo Van der Waal’s type interactionwhich is achievable by raising the stoichiometric ratio to 1:3 and beyond. Weak CTabsorption (700-800 nm) and emission bands (800 nm) characterizing supramolecularcomplexation, were noticed only in polar solvent acetonitrile. When applied as acomponent of the active layer in bulk heterojunction hybrid solar cells, the dyefunctionalized ZnO nanoprods raised the efficiency of the solar cells at lowconcentrations but addition of fullerene had an inverse effect. This was investigated to bedue to the morphological defects induced by the clusterization of nanorods
Fouchet, Arnaud. "Croissance et caractérisations de films minces de ZnO et ZnO dopé cobalt préparés par ablation laser pulsé". Caen, 2006. http://www.theses.fr/2006CAEN2050.
Pełny tekst źródłaSpintronics is an emergent area of research that exploits the quantum propensity of electrons to spin as well as utilizing their charge state, allowing microelectronic devices to be devised with additional functionality. Indeed, a great deal of research activity has been focused on dilute magnetic semiconductors (DMS) owing to their potential application as room temperature spintronic devices. This is based on recent theoretical calculations that predict it is possible to design DMS materials possessing ferromagnetic transitions (FM-Tc) above room temperature by doping a magnetic element into a host wide bandgap semiconductor (e. G. , Co-doped ZnO). However, the origin of ferromagnetism in these DMS materials is still subject of controversy, and questions remain : - is ferromagnetism in DMS intrinsic or extrinsic ? and - what is the mechanism relative to the magnetic interactions ? To address these questions, we have developed a novel strategy for the pulsed laser deposition of Co-doped ZnO films that utilizes metallic targets as the source of cationic elements. First, the growth conditions for ZnO films were optimized, and then subsequently utilized to deposit Co-doped ZnO films. Second, because this method allows for the precise control of the Co/Zn composition the growth conditions for certain amounts of cobalt doped into ZnO also were systematically studied. As a result, we have correlated the presence of ferromagnetism to film defects, results which have supported by recent theoretical calculations. Moreover, these results were corroborated by a comparative study between Co-doped ZnO films grown by ceramic and metallic targets
Achard, Nathalie. "Synthèse d'oxydes mixtes stabilisant Sb et Bi par oxydation directe d'un alliage précurseur (O. D. A. P. ) : implication dans la microstructure des céramiques électriques ZnO". Lyon 1, 1996. http://n2t.net/ark:/47881/m60c4t56.
Pełny tekst źródłaSarpi, Brice. "Etude in-situ de la formation d'oxyde ultra-mince de magnésium sur substrats métalliques et semi-conducteurs". Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4329/document.
Pełny tekst źródłaThis PhD work was dedicated to studying the fundamental mechanisms driving the controlled growth of ultra-thin oxide films. An experimental set-up was designed to finely control the growth parameters under UHV conditions while allowing the study of such oxide layers in situ with STM-STS, AES and LEED. Using an original method based on alternate cycles of Mg monolayer adsorption and RT oxidation, we focused on the formation of systems exhibiting a wide range of potential applications: MgO/Si(100) and MgO/Ag(111). The MgO/Si(100) system revealed the growth of an ultra-thin Mg2Si layer at the interface between the MgO and the silicon. In agreement with thermodynamic calculations, a crystallization of this interlayer driven by a partial decomposition of the Mg2Si to a MgO oxide was shown to occur at RT. From ex situ TEM experiments, the involved epitaxial relationship highlighted the formation of an MgO / Mg2Si (11-1) / Si(001) heterostructure. A sharp interface with the silicon was formed, as much as an ultra-thin and amorphous MgO layer exhibiting both a good homogeneity and a high insulating character (bandgap of 6 eV).In the MgO/Ag(111) system, no interfacial alloy formation and a « liquid-like » growth for the Mg were evidenced at RT, using our experimental results coupled with the ab initio calculations performed by our co-workers at LAAS laboratory. Later, a double-layering O/Mg/O/Mg/Ag(111) grown at RT followed by UHV annealing at 430°C resulted in the stabilization of a polar MgO(111) ultra-thin film, which was characterized using LEED and STM-STS. The physicochemical properties of this polar oxide and the potential origin of its stability were discussed