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Rmili, Seddik. "Préparation de catalyseurs bimétalliques Pt-Cu [platine-cuivre] par réaction redox de surface". Poitiers, 1995. http://www.theses.fr/1995POIT2300.
Pełny tekst źródłaMeunier, Isabelle. "Des divers modes de relaxation des contraintes induites par le désaccord de maille dans les alliages de surface". Aix-Marseille 2, 2001. http://www.theses.fr/2001AIX22038.
Pełny tekst źródłaAbrasonis, Gintautas. "Nitruration par faisceau d'ions des aciers austénitiques inoxydables : étude du transport atomique d'azote, des effets de flux et des effets structuraux". Poitiers, 2003. http://www.theses.fr/2003POIT2291.
Pełny tekst źródłaVERON, MARIE-BENOITE. "Etude des reconstructions de surface de cdte par diffraction de rayons x et d'electrons en incidence rasante". Paris 6, 1996. http://www.theses.fr/1996PA066428.
Pełny tekst źródłaLegagneux, Nicolas. "Chimie organométallique de surface sur hétéropolyacides supportés et non supportés : application à l'oxydation partielle du méthane en méthanol". Lyon 1, 2009. http://www.theses.fr/2009LYO10033.
Pełny tekst źródłaThe aim of this work was the synthesis and characterization of organometallic complexes grafted on silica supported ans unsupported heteropolyanions. PtMe2(COD) react on silicotungstic acid (H4SiW12O40) in an homogeneous way to form [SiW12 O10 4-] [Pt+Me(COD)(DMSO]4. DMSO. This reaction allow the formation of ionic interactions between the metallic center and the heteropolyacid which keeps his Keggin structure. The reaction with tetramethyltin gives this species : [SiW10 O40 4-] [Sn+ Me3 (DMSO)2]4. 2 DMSO. The supported heteropolyacids keep their Keggins structure and, for silicotungstic acid, an acidic proton remains on the polyanion. This acidic proton reacts stoichiometrically with PtMe2(COD) with quantitative release of methane. In an other hand, the silica supported silicotungstic acid behaves as a catalyst for the grafting reaction of tetramethyltin over the silanols of the silica surface. [SiW12 O10 4-] [Pt+Me(COD)(DMSO]4. DMSO. And oleum allow us to increase the TON of the oxidation of methane into methyl bisulfacte to 69
Medeiros, Soares Marcio. "Croissance, structure et magnétisme dans les systèmes à décalage d'échange FM/AFM : approche fondamentale par la physique des surfaces". Thesis, Grenoble, 2011. http://www.theses.fr/2011GRENY022/document.
Pełny tekst źródłaOur aim is to study the interaction of antiferromagnetic and ferromagnetic materials with well-defined interface by combining structural, electronic and magnetic techniques using synchrotron light. Our interest is guided by the exchange bias effect in thin ferromagnetic films with perpendicular magnetic anisotropy. The main systems studied in this work were ultra-thin layers of chemically-ordered alloys of FePt and MnPt on Pt(001) and of Fe/Ag(001), eventually coupled to CoO. Our strategy was to find an appropriate surface and, for each coupled bilayer, study the individual growth of each element, alloy or oxide. By controlling a variety of parameters, such as surface structure, cleanliness, deposition rate and temperature, we have got a good understanding of the growth process. The coupled systems obtained were studied in situ by grazing incidence X-ray diffraction and ex situ by magneto-optic Kerr effect, X-ray magnetic circular dichroism and X-ray absorption spectroscopy. The relation between the exchange coupling, which manifests itself by an increase in coercivity and a bias field, and the structural characteristics was discussed for the MnPt/FePt and CoO/Fe interfaces.Keywords: exchange bias, chemically ordered alloy, MnPt, FePt, Fe/Ag(001), surface X-ray diffraction, X-ray absorption, MOKE, synchrotron
Dalmas, Julie. "Etude expérimentale et théorique de l'interface Pb/Ag(111) : alliage et "désalliage" de surface". Aix-Marseille 2, 2005. http://www.theses.fr/2005AIX22017.
Pełny tekst źródłaButtard, Denis. "Étude structurale du silicium poreux de type p par diffraction haute résolution des rayons X". Université Joseph Fourier (Grenoble ; 1971-2015), 1997. http://www.theses.fr/1997GRE10141.
Pełny tekst źródłaHuet, Isabelle. "Elaboration et caractérisation de films minces de LiNbO3 et LiTaO3 en vue de la réalisation de filtres à ondes acoustiques de surface". Montpellier 2, 2001. http://www.theses.fr/2001MON20112.
Pełny tekst źródłaSoares, Marcio. "Croissance, structure et magnétisme dans les systèmes à décalage d'échange FM/AFM : approche fondamentale par la physique des surfaces". Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00603754.
Pełny tekst źródłaGognau, David. "Contraintes résiduelles introduites par des opérations de parachèvement de l'état de surface sur un acier de construction". Rouen, 2003. http://www.theses.fr/2003ROUES016.
Pełny tekst źródłaThis work deals with the characterization of states of surface and residual stresses associated to various types of machining: truing, grinding and brushing. This study is led on low carbon steel. States of surface are characterized by 2D roughness measurement and residual stresses are determined by X-rays diffraction. After having dedicated a part to optimisation and validation of the experimental methods and procedures, we study the effects of each of the types of machining previously quoted on the states of surface and on the residual stresses. We study first of all the effects of truing then those of grinding. We distinguish manual grinding of grinding realized by means of a test rig. We study then the brushing and end by the study of grinding - brushing coupling
BOUCHET-BOUDET, NATHALIE. "Etude par diffraction de rayons x d'heterostructures epitaxiees a base des semi-conducteurs ii-vi cdte et znte". Université Joseph Fourier (Grenoble), 1996. http://www.theses.fr/1996GRE10153.
Pełny tekst źródłaRohart, Emmanuel. "Préparation de catalyseurs bimétalliques Pd-Au [palladium-or] par réactions de surface contrôlée : caractérisations physico-chimiques et activité catalytique". Poitiers, 1997. http://www.theses.fr/1997POIT2357.
Pełny tekst źródłaDelheusy, Mélissa. "X-ray investigation of Nb/O interfaces". Paris 11, 2008. http://www.theses.fr/2008PA112104.
Pełny tekst źródłaX-ray free electron layers and the future International Linear Collider project are based on the performance of niobium superconducting rf cavities for efficient particle acceleration. A remarkable increase of the rf accelerating field is usually achieved by low-temperature annealing of the cavities (T <150°C, several hours). The microscopic origin of this effect has remained unclear; however, it has been argued that a redistribution of subsurface interstitial oxygen into niobium is involved. Ln this study, the near surface structure of oxidized niobium single crystals and its evolution upon vacuum annealing has been studied by means of non-destructive in-situ surface sensitive x-tay techniques : x-ray reflectivity (XRR) , grazing incidence x-ray diffraction (GIXD), diffuse scattering (GIDXS), crystal truncation rods measurements (CTRs), and high-resolution core-level spectroscopy (HR-CLS). A first insight into the interplay between the oxide formation/dissolution and the occurrence of subsurface interstitial oxygen has been given. The natural oxide on Nb(110) and Nb(100) surfaces is constituted of Nb2O5, NbO2 and NbO, from the surface to the interface. It reduces progressively upon heating from Nb2O5 to NbO2 at low temperatures, and to NbO at 300°C. The Nb(110)/NbO(111) interface presents a Nishiyma-Wasserman epitaxial orientation relationship. The depth-distribution of interstitial oxygen has been established indicating that most of the oxygen is located in the direct vicinity of the oxide/niobium interface. No evidence of oxygen depletion below the oxide layer has been observed for the low temperature thermal treatments and surface preparations investigated in this study
Berend, Isabelle. "Les mécanismes d'hydratation de montmorillonites homoioniques pour des pressions relatives inferieures à 0. 95". Vandoeuvre-les-Nancy, INPL, 1991. http://www.theses.fr/1991INPL072N.
Pełny tekst źródłaEtienne, François. "Etude du cardiolipide dans des membranes biologiques modèles : vésicules et monocouches de phosphatidylcholine". Paris 5, 2005. http://www.theses.fr/2005PA05S004.
Pełny tekst źródłaCardiolipin is located in the inner mitochondrial membrane where phosphatidylcholines are in the majority. We determined the influence of cardiolipin on model phospholipidic membranes, Langmuir monolayers and multilamellar vesicles, made up of dipalmitoylphosphatidylcholine (DPPC). These two phospholipids are miscible in mixed films, when the composition of the sub-phase is close to physiological conditions. Cardiolipin structures the monolayer and modifies the steric constraint which rules the stacking of this phospholipid in the form of bilayers. The modifications induced by the presence of the cardiolipin in model membranes are related to its polymorphism and the acid anionic nature of its head; the two parameters are correlated and essential to its miscibility with DPPC
Koerin, Régis. "Influence du mode de synthèse de la boehmite sur l’état de surface de l’alumine gamma mise en forme : application au reformage catalytique". Caen, 2014. http://www.theses.fr/2014CAEN2030.
Pełny tekst źródłaThis work investigates the relationships between the surface state of-alumina, its acidity after chlorination (1wt. %Cl) and the performances of the associated Pt/Al2O3-Cl catalysts in naphtha reforming. The alumina surface state, characterized by IR spectroscopy, strongly depends on the morphology of the parent boehmite, the proportions of its crystallographic faces being determined by XRD. Different conditions for kneading/extrusion and thermal treatments are applied to each boehmite to obtain alumina extrudates with similar textural properties. These additional treatments also modified the alumina surface state. Rehydration of the extrudates, the first step of the Pt active phase impregnation, tends to level these differences. 2,6-Lutidine thermo-desorption monitored by IR spectroscopy reveals differences in acidity related to both the chlorine content and the alumina morphology. It is also observed that with smaller particles, the concentration of Brønsted acid sites increases, indicating that edge sites play a key role in generating the Brønsted acidity of alumina particles. For alumina with a high proportion of (110) surface (70%), the increased chlorine content leads to a higher amount of Brønsted acid sites, whereas the opposite occurs with a lower proportion (50%) of such a surface. The catalytic performances in the reforming of n-C7 indicate that the only Brønsted acid sites involved are those closest to platinum nanoparticles. Finally we provide evidence for a relationship between the Lewis acid sites strength and the hydrogenolysis selectivity
Meneau, Caroline. "Croissance de nitrure d'aluminium par traitements plasma de surface d'Al ; corrélations entre microstructure, état micromécanique et comportement tribologique". Poitiers, 1998. http://www.theses.fr/1998POIT2304.
Pełny tekst źródłaGay, Marine. "Développement de nouvelles procédures quantitatives pour une meilleure compréhension des pigments et des parois des grottes ornées préhistoriques". Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066236/document.
Pełny tekst źródłaThe present study is a physicochemical research as well as a methodological work, carried out through the study of three Palaeolithic caves by X-ray fluorescence and X-ray diffraction. The analytical complexity behind in situ and non-invasive study of rock art, has guided our reflexion about the development of quantitative procedures of data processing, in order to adjust them appropriately to the specificity of the site and its rock art (specific constitution of the analysed pigment and conservation condition of the ornamented wall). This complexity is due to the fact that pigment layers don’t cover uniformly the rock surface. Also, the layers are generally very thin. For this reason, in the pigment signal, the proportion of the physicochemical information specific to the substrate is very high.Three approaches have been tested in the caves of Rouffignac, Font-de-Gaume and La Garma to characterise their Palaeolithic rock art. The two first are located in the Périgord region in the south-west of France, the last one in the Cantabrian region of Spain. One is related to the semi-quantification of oxides which discriminate the pigment from the substrate, allowing to not taking account experimental condition parameters; the second is a semi-quantification related to Ca, in order that the contribution in the concentration of the substrate detected through the paint layer remains the same for each measurement point; the last one is based on a Monte Carlo simulations method to separate distinctly the pigment information to those from the wall. These quantitative approaches enhanced the stylistic knowledge of archaeologists, bringing new physicochemical insights into the organisation of the representations and their relationship with the others inside the cave. Also, this work is concerned by the karstic environment; incorporating a research on wall taphonomy to the pigment study. The aim is to access to a better appreciation of the pigment-wall interactions and their evolution during time, given their global environmental context
Badawi, Kheireddine. "Etude des contraintes résiduelles par diffraction des rayons X et des caractéristiques géométriques des surfaces sablées de l'acier XC18". Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb37595633w.
Pełny tekst źródłaBROSSARD, FABIEN. "Etudes in-situ d'interfaces creees par voie electrochoimique par les techniques d'ondes stationnaires de rayons x et de diffraction de surface sous incidence rasante". Paris 7, 1997. http://www.theses.fr/1997PA077183.
Pełny tekst źródłaCarpentier, Philippe. "Étude des transitions de phase du cristal ferroélectrique (CH3NH3)5Bi2Cl11 (PMACB) : structure et dynamique". Lille 1, 1995. http://www.theses.fr/1995LIL10165.
Pełny tekst źródłaJacobsoone, Virginie. "Synthèse et caractérisation de phases oxyfluorées de type BIMEVOX et de verres oxyfluorés à base de Bi2O3". Lille 1, 1999. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/1999/50376-1999-15.pdf.
Pełny tekst źródłaCompte tenu de la formule chimique des échantillons appartenant à ce domaine, un excès de Zn est nécessairement présent, mais aucune trace d’oxyde de zinc n’a pu être détectée sur les clichés de idffraction des rayons X sur poudre. La spectroscopie de diffusion Raman a permis de mettre en évidence une continuité entre les phases cristallisée et vitreuse. En accord avec l’évolution progressive et continue des spectres lorsque l’on passe de la phase cristallisée à la phase vitreuse, l’hypothèse la plus problable conduit à la délocalisation des ions Zn2+ à la périphérie du feuillet pérovskite. Cette hypothèse est en accord avec la forte augmentation du paramètre c. Par recuit, la phase G se transforme progressivement en phase de type C. Les échantillons de la phase G partiellement recristallisée présentent en mesures électriques une augmentation importante des valeurs de Sigma sont 50 fois supérieures à celles des échantillons vitreux correspondants (Sigma=4. 10-4 S. Cm-1 à 260 °C pour Bi0,65Zn1,215V0,135O1,313F2,43). Une étude des systèmes Bi3O3-PbO-PbF2 et Bi2O3-PbO-CdF2 a également été réalisée. Les synthèses ont été effectuées en creusets de quartz et ont permis d’isoler un large domaine vitreux s’étendant vers le binaire Bi2O3-PbO. Les analyses par fluorescence X ont montré que tous les échantillons incorporent une grande quantité de silice durant la synthèse. Les mesures de conductivité réalisées par spectroscopie d’impédance ont révélé une augmentation de Sigma avec le nombre d’ions F-
Marciszko, Marianna. "Diffraction study of mechanical properties and residual stresses resulting from surface processing of polycrystalline materials". Thesis, Paris, ENSAM, 2013. http://www.theses.fr/2013ENAM0037/document.
Pełny tekst źródłaMethodology of stress measurements with multireflection grazing incidence method (MGIXD)was investigated and developed. The parallel beam geometry was applied. The incident beam in classicaldiffractometers was collimated by Göbel mirror and the tests of parallel configuration were performed for Alpowder. Results confirmed that both statistical error and the misalignment error can be reduced when theGöbel mirror is used. Physical factors were taken into account in XSA (X-ray stress analysis): Lorentzpolarizationand absorption factor (LPA) and also refraction correction (RC). Results showed that theinfluence of LPA correction is minor in XSA but the RC can significantly influence analysis. In the thesisthe issue of RC was considered and compared with approaches presented in the literature. In the thesistwo theoretical developments of the MGIXD method were presented: the procedure of c/a parameterdetermination and the influence of stacking faults on the results was taken into account. It was shown thatboth developments significantly improves the quality of experimental data analysis. In the present work theproblem of X-ray stress factors (XSF) used for the interpretation of XSA results was studied. Differenttheoretical grain elasto-plastic interaction models were considered and applied in XSA. Verification of theXSF was during tensile test for austenitic stainless steel and for the isotropic sample. Anisotropy of XSFwas also observed in: ground Ni alloy, polished austenitic stainless steel and CrN coating. The resultsshows that Reuss and free surface grain interaction models are in the best agreement with theexperimental results. Finally the MGIXD method was verified using synchrotron radiation and 3 differentwavelengths. The methodology was developed to treat data not only for different incident angles but alsousing simultaneously different wavelengths. Stresses vs. z – ‘real depth’ was calculated using the inverseLaplace transform applied to polynomial function. Wiliamson-Hall analysis was applied for collected data.Next multireflection method was applied for the energy dispersion diffraction measurements in which whitebeam containing radiation having different wavelengths was used (λ (Ǻ): 0.3–0.18/ E (keV): 40-68). Thestress analysis was performed using three different methods: standard sin2ψ method, Universal plotmethod and by using multireflection analysis. In the range of penetration depth to 0-15 μm theconvergence of the results obtained from different methods was gained. Moreover the synchrotron dataperfectly agree with the results obtained on laboratory diffractometer (Cu Kα radiation) close to the surface.For depth larger than 14 μm the experimental points exhibit significant spread and do not agree with theresults of standard method
Freitas, Hugo Eugênio de 1991. "Difração Bragg-Superfície (BSD) de raios X no estudo do efeito do tratamento térmico em Si(111) implantado com íons Cr+". [s.n.], 2016. http://repositorio.unicamp.br/jspui/handle/REPOSIP/305749.
Pełny tekst źródłaDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin
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Resumo: No presente trabalho estudou-se a diferença entre dois tratamentos térmicos realizados em amostras de Si(111) implantadas com íons Cr+, utilizando-se a difratometria de raios X para policristais e a refletividade de raios X, assim como, curvas de rocking e difração múltipla de raios X usando radiação sincrotron que são aplicadas aos monocristais. O tratamento térmico posterior das amostras resulta numa melhoria da qualidade cristalina, mas leva à formação de trincas e extensos defeitos, devido à grande diferença na expansão térmica entre siliceto e silício pelas altas tensões induzidas. Portanto, há um grande interesse tecnológico na obtenção de camadas contínuas de alta qualidade com um mínimo de distorções induzidas no substrato. Esta é a motivação do presente trabalho: obter camadas finas de CrSi2 de alta qualidade cristalina na subsuperfície de substratos Si(111) e com o mínimo de deformações na matriz hospedeira usando implantação de íons a baixa energia. Serão explorados dois distintos tipos de tratamentos térmicos: o recozimento tradicional a vácuo em forno do tipo mufla (FA - furnace annealing) e o recozimento térmico rápido (RTA - rapid thermal annealing) em atmosfera de argônio. A formação da fase semicondutora hexagonal do CrSi2 foi confirmada por difratometria de raios X nas amostras tratadas termicamente e mostrou uma melhor qualidade cristalina obtida no recozimento FA. O modelo proposto de uma camada superficial de SiO2 fina (8?2) nm sobre uma ou duas camadas de CrSi2 (21?5) nm acima do substrato de Si(111) foi confirmado, a partir das medidas de refletividade de raios X, que também permitiu observar a maior difusão dos íons de Cr+ na amostra tratada com FA por maior tempo. Devido a este tratamento térmico promover, a altas temperaturas, uma maior difusão dos íons implantados, concluiu-se que o tratamento térmico mais propício para a fabricação de semicondutores baseados em CrSi2 é o tratamento por RTA. Varreduras Renninger obtidas da difração múltipla de raios X mostraram que a implantação de Cr+ em Si(111) e posterior recozimento não induz alteração de simetria nas amostras, apenas uma pequena relaxação da distorção tetragonal detectada para a amostra 800º C com tratamento FA. Mapeamentos acoplados dos ângulos de incidência (?) e azimutal (?) para a condição exata de reflexões secundárias Bragg-Superfície (BSD) da difração múltipla não permitiram detectar modificações estruturais de superfície nas amostras analisadas, após os dois tratamentos térmicos a 800º C que foram considerados
Abstract: In this work, the effect of the two heat treatments suffered by Si(111) samples implanted with Cr+ ions has been studied by means of X rays powder diffraction and X rays reflectivity, as well as, the single crystal techniques rocking curves and synchrotron X rays multiple diffraction. The heat treatment of the samples subsequent to the implantation results in an improved crystal quality, but leads to cracks formation and extensive damage due to the large difference between the thermal expansion coefficients of silicide and silicon induced by the applied high voltages. Therefore, there is a great technological interest in obtaining high quality continuous layers with a minimum induced distortion into the substrate. This is the motivation of the present work: to obtain CrSi2 thin layers of high crystalline quality in the subsurface of Si(111) substrates with minimal deformations in the host matrix using low energy ion implantation. Two distinct thermal treatments are analyzed: traditional annealing in vacuum oven muffle type (FA - furnace annealing) and rapid thermal annealing (RTA - rapid thermal annealing) in argon atmosphere. The formation of the semiconductor CrSi2 hexagonal phase was confirmed by X ray powder diffraction in the annealed samples that has also shown an improved crystalline quality observed in FA annealing process. The proposed model of a thin (8?2) nm SiO2 surface layer on top of one or two (21?5) nm thick CrSi2 layers above the Si(111) substrate was confirmed from the X ray reflectivity measurements, that has also allowed to observe further diffusion of Cr + ions into the sample implanted and FA annealed for a longer time. Since this heat treatment promotes, at high temperatures, a greater diffusion of the implanted ions, it was found that RTA is the most suitable treatment for the fabrication of semiconductor-based CrSi2. Renninger scans of the X ray Multiple Diffraction have shown that the Cr+ ions implantation in Si(111) process with a subsequent annealing does not induce symmetry change in the samples, just a small relaxation of the tetragonal distortion detected for the 800 ºC sample after FA treatment. Mappings of the incidence (?) and azimuthal (?) coupled angles monitoring the exact multiple diffraction condition for the Bragg-Surface Diffraction (BSD) secondary reflections were not able to detect structural changes along the analyzed samples surfaces, after the two distinct annealed processes considered at 800º C
Mestrado
Física
Mestre em Física
132986/2014-0
CNPQ
Matringe, Caroline. "Nanostructuration bidimensionnelle de surfaces vicinales de saphir : Etude quantitative par diffusion et diffraction des rayons x sur sources de lumière synchrotron". Thesis, Limoges, 2016. http://www.theses.fr/2016LIMO0032/document.
Pełny tekst źródłaNanostructured systems based on nanoparticles deposited onto oxide surfaces have both a fundamental and technological interests. Final properties of such systems depend mostly on the shape and size of the nanoparticles and also on their spatial organization on the surface. In this general context, the use of vicinal surfaces appears to be an interesting way of producing templates for ordering nanoparticles. This work is devoted to the study of two-dimension (2D) nanostructuration of sapphire vicinal surfaces obtained under specific experimental conditions (vicinal surface orientation and thermal treatment parameters). The main objectives of this study were to describe the surface morphology of the samples having the 2D ordering and also to propose a mechanism regarding the transition from the 1D to the 2D ordering.Morphology of sapphire vicinal surfaces, annealed at 1250 °C under pure oxygen atmosphere during various durations up to 380 h, was studied by complementary technics: atomic force microscopy (AFM), grazing-incidence small-angle X-rays scattering (GISAXS), and grazing-incidence X-rays diffraction (GIXD). Results allowed us to describe the 2D ordered surface by being an assembly of pyramids with an isosceles triangle base decorating a rectangular centered lattice. The shape of those irregular tetrahedrons has been precisely determined with the crystallographic characteristics of sapphire. It has also been shown that a meandering step-edge phenomenon is probably the starting point of the transition between 1D and 2D lattices obtained when initial step-edges are straight
Chauveau, Jean-Michel. "Influence des conditions de croissance sur la qualité structurale et la morphologie de surface de rampes à composition graduelle InAlAs sur GaAs : application aux HEMTs métamorphiques". Lille 1, 2001. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2001/50376-2001-297.pdf.
Pełny tekst źródłaFouquet, Valérie. "Etude des mécanismes d'implantation et diffusion lors de la nitruration du titane et de Ti-6Al-4V par implantation ionique en immersion plasma". Poitiers, 2004. http://www.theses.fr/2004POIT2271.
Pełny tekst źródłaThe aim of this work is to study the implantation and diffusion mechanisms occuring during nitridation of titanium and of Ti-6Al-4V by plasma based ion implantation. Chemical and microstructural studies allow the determination of the characteristics of the phases formed depending on the treatment parameters. The implantation is the main formation mechanism of nitrides at low temperature whereas the nitridation is mainly controlled by the thermally activated diffusion at high temperature. By means of a numerical resolution of the equation of diffusion taking into account the experimental observations, implantation-induced defects have been shown to enhance the diffusion coefficient in the nitride layer. The in-depth nitridation of titanium is however favoured by the continuously implanted nitrogen in the nitride layer which acts as an in-depth source. On the contrary, in a thermal-activated treatment, the nitride forms a diffusion barrier which limits the later incorporation of nitrogen
Antad, Vivek Vishwanath. "Contrôle de la croissance et de la réactivité de nanoparticules métalliques par spectroscopie optique in situ". Poitiers, 2011. http://nuxeo.edel.univ-poitiers.fr/nuxeo/site/esupversions/35759283-29ff-4bbd-a574-690c779b5431.
Pełny tekst źródłaA non-intrusive in situ surface differential reflectance spectroscopy (SDRS) is adapted on a magnetron sputtering deposition technique in order to study the optical properties of metal: dielectric nanocomposites in real-time during their alternate depositions. SDRS is helpful in studying optical properties of metal nanoclusters which are dominated by the surface plasma resonance (SPR), which is sensitive, not only to the morphology and organization of the nanoclusters, but also to their physical and/or chemical surroundings. Hence, to establish the correlation between the optical properties of nanoclusters and their nanostructure, post mortem high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and grazing-incidence smallangle X-ray scattering (GISAXS) techniques are implemented. Following the signature SPR in real-time helps us not only to understand the different growth regimes through which the metal nanoclusters evolve, but also to study the effects caused by the physical and/or chemical treatments (such as, exposure of nanoclusters to different gases, either non-ionized or partially ionized, thermal annealing, and low-energy plasma annealing). Finally, the influence of a dielectric (Si3N4) capping matrix on the optical properties of the metal nanoclusters is equally studied after each physical and/or chemical treatment. In this way, the in situ optical spectroscopy allows us to monitor the optical properties of nanocomposites thin films during all the deposition steps and the additional post mortem structural characterization techniques help us to understand the different phenomena taking place at the nanoscale
Hwang, Bing-Hwai. "Near surface wear structure of ceramic components". Diss., Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/87668.
Pełny tekst źródłaPh. D.
Duprès, Vincent. "Surfaces hétérogènes controlées et systèmes diphasiques bidimensionnels". Cergy-Pontoise, 2001. http://biblioweb.u-cergy.fr/theses/01CERG0128.pdf.
Pełny tekst źródłaThis thesis presents the elaboration and the characterisation of controlled heterogeneous surfaces in order to study the effect of the heterogeneities on the wetting properties. These surfaces are obtained by preparing Langmuir-Blodgett films with a mixture of two amphiphilic molecules. These molecules were chosen for their different wetting properties : the first one is a long chain fatty acid while the second one is a partially fluorinated surfactant. The mixed films are first characterised at the air-water interface (Langmuir monolayers). In order to determine the mixing behaviour of the two molecules, the mixed films were studied at different scales using several experimental techniques. The results show that a complete phase separation takes place over the whole range of molar fractions and whatever the surface pressure. Circular domains of the fatty acid are evidenced. The mixed films are then transferred on solid substrate. In order to obtain well anchored films, the transfer parameters were adapted. The molecular arrangement in the films is determined using grazing incidence X-ray diffraction with two angles of incidence of the beam to change its penetration depth. We also used atomic force microscopy to obtain surface topography and to check on the absence of defects. In the same way as at the air-water interface, circular domains are visualised. These domains coexist with a continuous phase which presents a labyrinthine structure attributed to a molecular reorganisation during transfer. Then, we obtain a system that appears well adapted to study the wetting properties of heterogeneous surfaces : the two molecules are completely phase-separated and each phase has different properties
Pédèche, Stéphan. "Etude in situ du mécanisme de fusion d'un mélange vitrifiable : application au verre E". Orléans, 2002. http://www.theses.fr/2002ORLE2024.
Pełny tekst źródłaMasri, Talal. "Détermination des contraintes interfaciales sur des duplex verre/métal à gros grains : utilisation de la diffraction x et de la microdureté Vickers". Toulouse, INPT, 1991. http://www.theses.fr/1991INPT028G.
Pełny tekst źródłaGoapper, Sylvain. "Morphologie de surface et ordre chimique : Faces vicinales d'alliage cuivre-palladium". Phd thesis, Université de Marne la Vallée, 1998. http://tel.archives-ouvertes.fr/tel-00243115.
Pełny tekst źródłaLa diffraction de rayons X à l'ESRF nous a permis d'observer l'apparition du désordre chimique à la surface et l'évolution simultanée du changement de structure des marches. On observe que la séparation des paires de marches évolue proportionnellement à la composante parallèle du paramètre d'ordre dans le plan de surface.
Pour des temps courts de mise en ordre, le STM montre une structure en domaines, des marches appariées. On identifie les frontières entre domaines par le dédoublement local des paires de marches. Ce phénomène traduit l'émergence à la surface de parois. Cette structure en domaine, caractéristique de l'ordre chimique dans les premiers plans de surface, nous a permis, par STM et diffraction d'hélium, de suivre la cinétique de mise en ordre en présence d'une surface. La taille caractéristique des domaines évolue avec le temps de recuit en A(T).t1/2. Un diagramme d'Arrhénius du facteur d'échelle temporel A(T) a permis de mesurer une énergie d'activation de mise en ordre de 2 eV à la surface ainsi qu'en volume.
Dans une seconde étude, nous avons caractérisé l'influence du dépôt de palladium sur une surface vicinale de cuivre. Nous avons montré par diffraction d'hélium que cet alliage de surface provoque un appariement des marches similaires à celles observées sur l'alliage massif Cu3Pd. Cependant, cette modification de la distribution des marches présente un faible degré d'ordre qui peut être du à l'absence d'ordre chimique à longue distance.
Zakri, Cécile. "Étude de la fusion-cristallisation de monocouches de 1-alcools à la surface de l'eau : mesures d'élasticité latérale par diffraction de rayons X et par une méthode mécanique". Université Joseph Fourier (Grenoble ; 1971-2015), 1997. http://www.theses.fr/1997GRE10107.
Pełny tekst źródłaOuerghi, Abdelkarim. "Croissance épitaxiale de MnAs sur GaAs(111) et étude des reconstructions de la surface de MnAs". Paris 6, 2004. http://www.theses.fr/2004PA066568.
Pełny tekst źródłaBeyerlein, Kenneth Roy. "Simulation and modeling of the powder diffraction pattern from nanoparticles: studying the influence of surface strain". Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41211.
Pełny tekst źródłaGilles, Bruno. "Etude par rayons X rasants des effets de l'implantation de silicium dans le silicium et de fer dans un grenat". Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb37597890r.
Pełny tekst źródłaZhang, Kai. "Structure and growth of germanene and silicene on Ag and Al surfaces". Electronic Thesis or Diss., Sorbonne université, 2021. http://www.theses.fr/2021SORUS438.
Pełny tekst źródłaWhile numerous interesting properties are expected from theoretical calculations for free-standing silicene and germanene, their synthesis remain controversial. This thesis presents an experimental study by scanning tunneling microscopy (STM) and grazing incidence X-ray diffraction (GIXD) of the growth of germanium and silicon on metal surfaces. Three systems have been studied: Ge/Al(111), Ge/Ag(111) and Si/Ag(110). Various ordered reconstructions are observed by STM, depending on the growth temperature. Real-time STM allows me to determine the transitions between these structures. For all cases, STM images acquired during growth show that surface atoms exchange with Si or Ge atoms during deposition. Three ordered structures have been quantitatively analyzed by GIXD. The experimental structure factors obtained have been further compared with the ones simulated from DFT models. For Ge/Al(111), I show that the (3×3) reconstruction corresponds to a two-layer Ge-Al surface alloy, and not to germanene as previously proposed. For Ge/Al(111), I demonstrate the formation of a Ag2Ge surface alloy with a structure similar to the (22×√3) reconstruction of Au(111). However, I demonstrate that further Si deposition on the Si pentamers previously observed on Ag(110) lead to the formation of a dumbbell silicene honeycomb ordered layer
Wu, Zhongming. "Diffraction studies of structure and growth of films absorbed on the AG(111) surface /". free to MU campus, to others for purchase, 1997. http://wwwlib.umi.com/cr/mo/fullcit?p9841195.
Pełny tekst źródłaBains, Jessica Johanna. "Optimisation de matériaux lamellaires d’électrode positive pour batteries lithium-ion de type Li1+x(Ni1/2-yMn1/2-yCo2y)1-xO2 via une modification de surface ou une substitution cationique". Thesis, Bordeaux 1, 2009. http://www.theses.fr/2009BOR13771/document.
Pełny tekst źródłaTwo approaches were considered for the optimization of Li1+x(Ni1/2-yMn1/2-yCo2y)1-xO2 positive electrode materials for lithium-ion batteries : the surface modification (coating) and partial substitution. First, we showed that fluorine substitution for oxygen is not effective, on the contrary to the hypotheses proposed in literature by others authors: in fact a thin LiF layer is formed at the surface of these materials irrespective of the synthesis route. These "coated" materials show a better cyclability. Their structural and physicochemical properties were characterized mainly by X-ray diffraction, 7Li and 19F MAS NMR spectroscopy and Auger electron spectroscopy. Secondly, we studied the effect of aluminum (electrochemically inert) substitution for cobalt within these layered materials rich in nickel and manganese. The synthesis conditions were optimized and an interesting material was thus proposed. The structure and cationic distribution were determined by chemical analyses, X-ray diffraction, magnetic measurements: aluminum substitution leads to a lower overlithiation, to a larger exchange Li+ / Ni2+ ratio and thus to a decreasing bidimensional character for the structure. These materials show a good cyclability even at high rates and an improved thermal stability in the deintercalated state
Jedrecy, Nathalie. "Etude de surfaces reconstruites et d'heteroepitaxies par diffraction des rayons x en ultra-vide sous incidence rasante gaas(001), de si(001) jusqu'a l'heteroepitaxie gaas/si". Paris 6, 1990. http://www.theses.fr/1990PA066179.
Pełny tekst źródłaAngelo, Marie d'. "Interaction de l'hydrogène, de l'argent et du sodium avec des surfaces de β-SiC(001) : organisation atomique, nanostructures et métallisation". Paris 11, 2003. http://www.theses.fr/2003PA112142.
Pełny tekst źródłaWe study clean and hydrogen, silver and sodium covered β-SiC(001) surfaces by scanning tunnelling microscopy (STM), synchrotron radiation based photoelectron spectroscopy and "grazing incidence X-ray diffraction (GIXRD). We determine unambiguously the atomic structure of the silicon-rich β-SiC(001) 3x2 surface and propose a new model called ALSD (Alternately Long and Short Dimers) showing the importance of surface stress on SiC surface organisation. By synchrotron based valence band photoemission and scanning tunnelling spectroscopy, we confirm the metallization of the silicon-rich, 3x2, surface upon atomic hydrogen exposure. We propose a mechanism for this metallization, in agreement with the ALSD model for the clean surface and the Si 2p core level photoemission data. We highlight, by STM, Ag clusters formation on the 3x2 surface. On the contrary, in the case of interaction with the Si-terminated, c(4x2), surface, the Ag atoms are adsorbed on pedestal sites. We observe two structures induced by silver: a 2x3 and a c(2x4) for which we propose a structural model. We also evidence room temperature anisotropic Ag diffusion, along the dimer rows of the c(4x2) surface. Interestingly, upon partial annealing of an Ag monolayer, one-dimensional nanostructures, perpendicular to the dimer rows are created. This result is interpreted in terms of diffusion barrier modification with temperature. In the case of sodium interaction with the Si-rich, 3x2, reconstruction, photoemission experiments show that the Si/Na bound is a weak covalent bound, while a plasmon feature at Na 2p core level evidences Na metallic clusters formation on the β-SiC(001) 3x2 surface
Bourniquel, Bernard. "Evaluation des deformations mecaniques de surface par diffraction x. Optimisation de la mesure des contraintes residuelles. Application au controle qualite du grenaillage de precontrainte". Nantes, 1988. http://www.theses.fr/1988NANT2037.
Pełny tekst źródłaFardeheb-Mammeri, Amina-Zahia. "Dépôt par pulvérisation magnétron de couches minces de nitrure d'aluminium à axe C incliné en vue de la réalisation de dispositifs à ondes acoustiques vibrant en mode de cisaillement". Thesis, Nancy 1, 2009. http://www.theses.fr/2009NAN10115/document.
Pełny tekst źródłaThe excitation and propagation, in liquid media, of shear waves in surface acoustic wave (SAW) devices based aluminum nitride (AlN) require the inclination of the c axis in the hexagonal structure. The purpose of this study was to deposit tilted c-axis AlN thin films by magnetron sputtering technique without any modification of the deposition system. The search approach was based only on the optimisation of deposition parameters. Substrate and the target were not inclined or shifted. It has been possible through an approach based solely on changes in growth parameters, to deposit thin piezoelectric layers with an inclination angle of 13 ° ± 2 ° under conditions of high pressure (0.8 Pa) and low temperature ( 300 ° C). A thin layer of SiO2 was also introduced to enhance the growth of tilted grains and therefore the columns. The deposited layers have a homogeneous thickness of 75% of a silicon substrate of 3 inches. After determining the optimal parameters leading to growth AlN film with tilted c-axis, we achieved a SAW device and hence demonstrate the ability to excite shear waves in AlN/Si02 /Si SAW structure. The performed device operate at 486.2 MHz corresponding to an acoustic velocity of about 5835m/s and an electromechanical coupling coefficient of 0.014%. The obtained electrical response is very interesting if we take into account the low electromechanical coupling of the structure due to the used substrate
Chambon, Carole. "Dépôts d'argent sur des surfaces de nickel : organisation et structure d'un système métal sur métal". Phd thesis, Université Paris-Diderot - Paris VII, 2009. http://tel.archives-ouvertes.fr/tel-00505723.
Pełny tekst źródłaBranger, Vincent. "Analyse microstructurale et mécanique de films minces métalliques obtenus par PVD [physical vapor deposition]". Poitiers, 1998. http://www.theses.fr/1998POIT2258.
Pełny tekst źródłaPierron, Thomas. "Contribution à l’étude des propriétés de l’interface métal oxyde GeO/Ru(0001) par STM, XPS/ARPES et SXRD". Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0160.
Pełny tekst źródłaThis thesis manuscript is dedicated to the study of silicon (SiO) and germanium (GeO) oxides in their ultra-thin forms. Developed by molecular beam epitaxy on the surface of a ruthenium (0001) crystal, these systems can exist in two stable phases. The first one is a monolayer connected to the substrate by covalent bonds forming a metal-oxide interface. The second one is a weakly interacting bilayer disconnected from the substrate. The weakness of the Van der Waals interactions allows its exfoliation to integrate it into functional heterostructures. In this thesis we study the relationship between structural and electronic properties of these two-dimensional (2D) materials by combining scanning tunneling microscopy (STM), angle-resolved photoemission (XPS, ARPES), surface X-ray diffraction (SXRD) and modelling by DFT methods. Some of our measurements (XPS, ARPES and SXRD) were obtained using synchrotron radiation. If the properties of the silicon oxide (SiO) bilayer are well understood, the description of the electronic properties of the metal-oxide interface proves to be more complex with the impossibility of reconciling the calculations with our ARPES measurements. To understand the origin of this disagreement, we studied the GeO/Ru(0001) interface in the monolayer regime. Our STM and XPS studies validated the atomic model proposed by DFT, including the rotation of Ge-O-Ge bonds and the presence of an interstitial oxygen. Complementary structural studies by SXRD validated the epitaxial relationship proposed by the calculation. Finally, the measured band structure is close to the DFT predictions, contrary to SiO, even if a small disagreement remains. This can be interpreted as an overestimation of the metal oxide bond strength by the calculation introducing a band gap at the Gamma point and at the K point not experimentally visible in ARPES in the case of SiO. Further SXRD measurements on SiO will support this hypothesis
Orloski, Renata Villela. "Difração Bragg-Superficie (BSD) : uma sonda de alta resolução para o estudo da implantação de íons em semicondutores". [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/278176.
Pełny tekst źródłaTese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica "Gleb Wataghin"
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Resumo: Neste trabalho, a difração Bragg-Superfície (BSD), um caso especial da difração múltipla de raios-X, foi usada como uma microssonda de superfície com resolução para a detecção de defeitos originados próximos da interface cristal-amorfo (c-a) em junções rasas de B em Si, e uma nova técnica de caracterização de semicondutores (GaAs) submetidos à implantação com íons de Si. A varredura Renninger é o registro da intensidade de raios-X difratada pelos planos, normalmente paralelos à superfície de um monocristal, em função da rotação ö em torno da normal à esses planos. Ela exibe picos como contribuições da rede da matriz, e no nosso caso, se o feixe difratado propaga-se paralelamente aos planos, os picos são chamados de difração Bragg-Superfície (BSD), e mostrou-se, pela primeira vez, que essa difração carrega informações sobre a interface c-a. Contribuições da região implantada nas junções rasas, detectadas na varredura para a rede da matriz (picos híbridos), permitiram determinar a presença de Si intersticial, responsável pela difusão do B, e estimar a profundidade da junção de B em Si pré-amorfizado com íons de F, confirmando resultado encontrado por espectroscopia de massa de íons secundários (SIMS). O estudo do efeito da energia e densidade de corrente de implantação, e da energia térmica conduziu às melhores condições para a otimização do processo de recristalização da rede e difusão do dopante, visando a obtenção das junções rasas. Já o mapeamento da condição de difração dos picos BSD foi importante na observação direta da recristalização e difusão do dopante. Parâmetros de rede e perfeição cristalina foram determinados na superfície da matriz GaAs(001) com dfiração múltipla e a simulação dos picos BSD mostrou que menores doses de implantação de íons Si causam os maiores defeitos no plano da superfície do GaAs, o que não acontece com as altas doses pelo efeito da intensa amorfização próximo à interface c-a. O mapeamento dos casos BSD mostraram sensibilidade suficiente para a detecção da formação da região implantada em função da dose nas amostras de GaAs implantadas com Si
Abstract: In this work, the Bragg-Surface Diffraction (BSD), a special case of the X-ray Multiple Diffraction, was used as a surface microprobe with resolution to detect the defects created close to the crystal-amorphous (c-a) interface in shallow junctions of B in Si, as well as a novel technique for characterization of semiconductors (GaAs) under Si ions implantation. Renninger scan is the record of the X-ray intensity diffracted by the planes, normally parallel to the single crystal surface, as a function of the ö rotation around the normal to these planes. It exhibits peaks as matrix lattice contributions and, in our case, if the diffracted beam is propagated along the planes, the peaks are called Bragg-Surface Diffraction (BSD) and, one has shown, by the first time, that this diffraction carries information on the c-a interface. Contributions from the shallow junction implanted regions, detected in the matrix lattice scan (hybrid peaks), allowed to determine the presence of interstitial Si, that is responsible for the B diffusion, and to estimate the B junction depth in Si pre-amorphizied by F ions. This result confirms that found by Secondary Ion Mass Spectroscopy (SIMS). The study of the effect of the energy and implantation current density as well as the thermal energy allowed to determine the best conditions for the optimization of the doping diffusion and lattice recrystallization process, aiming to the shallow junction preparation. On the other hand, the mapping of the BSD peak diffraction condition gave rise to the direct observation of both processes (recrystallization and diffusion). Lattice parameters and crystalline perfection were determined on the GaAs(001) matrix surface by using Multiple Diffraction and the BSD peak simulation has shown that low implantation doses of Si ions has caused strongest damages on the GaAS surface plane. To the contrary, in high doses this effect is strongly reduced by the intense amorphization close to the c-a interface. The BSD mappings have shown enough sensitivity to detect the implanted region formation as a function of the Si implantation dose in GaAs samples
Doutorado
Física da Matéria Condensada
Doutor em Ciências
Bains, Jessica. "Optimisation de matériaux lamellaires d'électrode positive pour batteries lithium-ion de type Li1+x(Ni1/2-yMn1/2-yCo2y)1-xO2 via une modification de surface ou une substitution cationique". Phd thesis, Université Sciences et Technologies - Bordeaux I, 2009. http://tel.archives-ouvertes.fr/tel-00575622.
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