Teses / dissertações sobre o tema "Spectrométrie de photon"
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Desjacques, Charlotte. "Apports des méthodes photon-in/photon-out à la compréhension des systèmes catalytiques complexes". Thesis, Lille, 2018. http://www.theses.fr/2018LIL1R013.
Texto completo da fonteThe aim of this PhD dissertation is to apply resonant inelastic X-Ray scattering (RIXS 1s2p) and high energy resolution partial fluorescence detection X-ray absorption spectroscopy (HERPFD-XAS) to the study in situ sulfurization of HDS catalysts. Indeed, only a detailed understanding of the structure and nature of the active phase of the catalysts at the molecular level makes it possible to improve their catalytic performance. After presenting a state of the art on the characterization of the active phase of hydrotreating catalysts, we have shown the potential of these spectroscopic methods through the study of cobalt-based reference compounds where cobalt is present in different symmetries with different oxidation states. These results reveal that these spectroscopic techniques are sensitive to the local coordination of cobalt, as well as to its electronic structure. Two samples were studied for in situ sulfurization: cobalt supported on alumina and cobalt-molybdenum supported on alumina. The HERPFD-XAS spectroscopy results at cobalt K-edge show CoS2 formation before the CoMoS and Co9S8 phases for both samples, as well as the constant contribution of CoAl2O4 (phase that does not undergo sulfurization). Analysis by 1s2p RIXS spectroscopy revealed that the cobalt, present in the active phase of the both catalyst, has a metallic character, which allowed to interpret in a finer way data published in the literature
Desjacques, Charlotte. "Apports des méthodes photon-in/photon-out à la compréhension des systèmes catalytiques complexes". Electronic Thesis or Diss., Université de Lille (2018-2021), 2018. http://www.theses.fr/2018LILUR013.
Texto completo da fonteThe aim of this PhD dissertation is to apply resonant inelastic X-Ray scattering (RIXS 1s2p) and high energy resolution partial fluorescence detection X-ray absorption spectroscopy (HERPFD-XAS) to the study in situ sulfurization of HDS catalysts. Indeed, only a detailed understanding of the structure and nature of the active phase of the catalysts at the molecular level makes it possible to improve their catalytic performance. After presenting a state of the art on the characterization of the active phase of hydrotreating catalysts, we have shown the potential of these spectroscopic methods through the study of cobalt-based reference compounds where cobalt is present in different symmetries with different oxidation states. These results reveal that these spectroscopic techniques are sensitive to the local coordination of cobalt, as well as to its electronic structure. Two samples were studied for in situ sulfurization: cobalt supported on alumina and cobalt-molybdenum supported on alumina. The HERPFD-XAS spectroscopy results at cobalt K-edge show CoS2 formation before the CoMoS and Co9S8 phases for both samples, as well as the constant contribution of CoAl2O4 (phase that does not undergo sulfurization). Analysis by 1s2p RIXS spectroscopy revealed that the cobalt, present in the active phase of the both catalyst, has a metallic character, which allowed to interpret in a finer way data published in the literature
Zahir, Mostafa Lokman. "Nouvelles références en énergie X et gamma inférieures à 100 keV établies à l'aide de calorimètres magnétiques ultra haute résolution". Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASP125.
Texto completo da fonteThe X and gamma rays emitted by radionuclides can be used to calibrate the energy scale of energy-dispersive detectors. This is particularly the case for cryogenic detectors, which offer excellent resolution but have non-linearities that need to be corrected. In order to calibrate these detectors accurately below 200 keV, it is necessary to have X-rays and gamma rays with an uncertainty of the order of 0.1 eV. However, recommended gamma-ray photon energies meeting this criterion are rare or based on a single experimental measurement. The main objective of this thesis is to measure gamma photons below 200 keV with excellent resolution in order to improve the uncertainties on their energies to around 0.1 eV. To meet this objective, a new cryogenic detector has been designed. It is a Metallic Magnetic Calorimeter (MMC) with eight 50 µm-thick gold absorbers covering a total surface area of 8.4 mm². An assembly was built to house: four MMC chips, two SQUID chips for reading-out the MMCs, and the printed circuits to connect them to the cables of the dilution refrigerator. The set-up also includes a cryogenic radioactive source sampler, specially designed to operate at very low temperatures and to measure up to four sources sequentially. The sources measured are mixtures of several radionuclides: three standard radionuclides used to correct the non-linearity of the MMC (169Yb, 57Co and 153Gd) and seven radionuclides used to measure their X and gamma energies with very low uncertainty (109Cd, 133Ba, 155Eu, 210Pb, 239Np, 241Am and 243Am). Mixtures of radionuclides in the sources were chosen by Monte Carlo simulations to minimise spectral interference. Ytterbium-169 was produced by irradiating a thulium foil with deuterons at the Arronax cyclotron.Two independent measurement sessions on two set of four sources were carried out at around 16 mK during two weeks, with different temperature control conditions. The energy resolution of the detector is 15 eV to 36 eV for gamma-rays between 0 keV and 200 keV. The non-linearity of each absorber was corrected using the lines of the standard radionuclides and a second-degree polynomial. The X-ray and gamma-ray energies measured were analysed and combined using various methods. Regardless ofthe measurement session and analysis method used, the energies obtained are consistent with each other, with only the uncertainties differing. In the end, the energies of 15 gamma-ray lines were measured and for 14 of them, the uncertainty obtained, around 0.2 eV, is lower than the recommended values. Eight Kα X-ray photon energies were also measured; for these well-known lines, very good agreement was observed with the recommended values, thus validating the methodology used in the work presented
Habib, Amr. "Détecteurs radiologiques grande surface, multi-énergie". Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENT055.
Texto completo da fonteThe objective of the thesis is to propose a solution for a 2D integrated circuit X-ray imager working, either in spectrometric mode where each X photon energy is measured, or in charge integration mode where the total energy deposited by X-ray during an image is measured, the solution being compatible with large area detectors typically of 20 cm x 20 cm. A proof of concept prototype ASIC 'Sphinx' was designed and fabricated in CMOS 0.13 µm technology; the ASIC being formed of a matrix of 20 x 20 pixels with a 200 µm pixel pitch. The designed architecture allows the quantification of the incoming charge through the use of counter-charge packets as low as 100 electrons. The injected packets are counted for each X photon (in the spectrometric photon counting mode), or for all charges integrated during the image period (in charge integration mode). First characterization measurements prove the validity of the concept with good performance in terms of power consumption, noise, and linearity. A first part of the ASIC is dedicated to X-ray direct detection where a semiconductor, e.g. CdZnTe, hybridized to the ASIC's pixels converts X-photons to electrical charge. Another part of the ASIC is dedicated indirect X-ray detection where a scintillator, e.g. CsI:Tl, is used to convert X-photons to visible photons which are then detected by in-pixel photodiodes. For the latter mode, new forms of photodiodes characterized by fast detection and low capacity were designed, simulated, and fabricated in CMOS 0.13 µm technology on a different ASIC. Finally, the thesis concludes with proposing performance enhancing ideas to be potentially implemented in a future prototype
Nazih, Abdelhamid. "Applications de la spectroscopie par corrélation de photons à : 1) la granulométrie des imbrûlés : 2) la vélocimétrie". Rouen, 1989. http://www.theses.fr/1989ROUES030.
Texto completo da fonteTrigano, Thomas. "Traitement statistique du signal spectrométrique : étude du désempilement de spectre en énergie pour la spectrométrie gamma". Paris, ENST, 2005. http://www.theses.fr/2005ENST0041.
Texto completo da fonteIn Gamma spectrometry, we characterize the radioactive elements of an unknown source by studying the energy of the emitted Gamma photons. At high counting rates, due to the stochastic aspect of the signal, the pileup phenomenon can cripple the identification of the radioactive elements. Specifically, close arrival times of photons which can be modeled as an homogeneous Poisson process cause a distortion of the energy spectra by introducing multiple fake spikes and prolonging artificially the Compton continuum, which can mask spikes of low intensity. The objective of this study is to correct the distortion caused by the pileup phenomenon in the energy spectra. We consider this problem in a nonparametric framework. Using a model based on two marked point processes, we establish a nonlinear relation between the probability measure associated to the observations and the probability density function we wish to estimate. This relation provides a framework to this problem, which can be considered as a problem of nonlinear density deconvolution and nonparametric density estimation from indirect measurements. Using these considerations, we propose an estimator obtained by direct inversion. We show that this estimator is consistent and almost achieves the usual rate of convergence obtained in classical nonparametric density estimation in the L2 sense. We illustrate these aspects by numerical results obtained both on simulations and on energy spectra associated to real-world data from the ADONIS intrumentation system developed by the CEA Saclay. We show that the distortions caused by the pileup phenomenon are well corrected by the algorithms derived from our estimators
Pinquier, Claire. "Étude Raman de semi-conducteurs nitruresCouches minces et nanostructures". Phd thesis, Université Paul Sabatier - Toulouse III, 2006. http://tel.archives-ouvertes.fr/tel-00135839.
Texto completo da fonteL'étude présentée porte en particulier sur les processus de relaxation des contraintes dans les îlots et les boîtes quantiques, ainsi que sur les mécanismes de diffusion inélastique de la lumière dans InN et la dynamique de réseau dans les nanostructures. Ce travail est fortement marqué par les aspects expérimentaux, et une part importante de ce manuscrit est consacrée aux résultats obtenus sous haute pression.
Pinquier, Claire. "Étude raman de semi-conducteurs nitrures : couches minces et nanostructures". Toulouse 3, 2006. http://www.theses.fr/2006TOU30142.
Texto completo da fonteThe light emission of group-III nitride semiconductors arouses a great interest due to their optoelectronic applications. We analyzed their optical, vibrational, electronic and crystallographic properties, in particular by means of Raman spectroscopy. Typical systems we investigated are paragons of the state of art of group-III nitride growth: we considered InN microscopic islands and films, as well as GaN/AlN heterostructures such as superlattices and quantum dots. We discussed strain relaxation processes in both islands and quantum dots, inelastic light scattering mechanisms involved in InN and lattice dynamics in nanostructures. The experimental aspect, especially under high pressure, constitutes an important part of this work
Bachelier, Guillaume. "Propriétés optiques de nano-structures métalliques et semi-conductrices". Phd thesis, Université Paul Sabatier - Toulouse III, 2004. http://tel.archives-ouvertes.fr/tel-00008229.
Texto completo da fonteSimon, Anne-Laure. "Couplage de la spectrométrie de mobilité ionique et de la spectroscopie optique : études conformationnelles en phase gazeuse". Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1128/document.
Texto completo da fonteThis thesis deals with the development of a new instrument coupling mass spectrometry, ion mobility spectrometry and laser spectroscopy. The aim is to perform structural analysis on biomolecular systems.The first part of this thesis focuses on the construction, the development and the optimization of the set-up. The main point was to determine the features of the set-up (resolution, working frequency) by series of tests with model systems.In a second phase, we did conformer resolved action spectroscopy. We studied the relation between the conformation and the optical properties of one system by measuring photo- electron detachment on different selected conformers. In the framework of action spectroscopy we used the new capacity of the set-up to perform cis-trans photo-isomerization on non-covalent complexes. We showed with this example interest of the use of this instrument to measure photo-isomerization action spectra. We finally showed the possibility to perform conformer resolved action spectroscopy measurements based on Förster Resonance Energy Transfer (FRET) in the gas phase
Hervé, Marie-Laure. "Dosimétrie d'accident en champ mixte (neutrons, photons) utilisant la spectrométrie par résonance paramagnétique électronique (RPE)". Paris 11, 2006. http://www.theses.fr/2006PA11T019.
Texto completo da fonteNemausat, Ruidy. "Etude expérimentale et théorique des fluctuations thermiques quantiques des noyaux par spectroscopies d'absorption X et RMN". Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066158/document.
Texto completo da fonteIn this thesis the impact of quantum thermal fluctuations on XANES and solid-state NMR spectra is described using an experimental and theoretical joint study. This project has two components. First, high-quality experimental data are acquired in order to observe and understand the influence of quantum vibrations in light-elements oxides. Second, a theoretical model is set up to reproduce the effects observed experimentally and describe their origin from a fundamental point of view. The developed theoretical approach is based on the density-functional theory. Within the Born-Oppenheimer and quasiharmonic approximations, the quantum thermal fluctuations of nuclei are modeled by generating atomic configurations obeying quantum statistics at finite temperature. The XANES spectra and NMR parameters are subsequently calculated in these configurations and the average results are compared with spectroscopic data at finite temperature. This approach has been validated by a joint theoretical-experimental study conducted in a series of light-element oxides, where the results were found to be in excellent agreement with the original experimental data. In addition, it is shown that the impact of the quantum fluctuations of the nuclei is influenced by the local symmetry of the probed atomic site
Sharifi, Kalahroudi Seyed Mehdi. "SOME ADVANCEMENT IN IONIZATION OF ATOMS AND MOLECULES IN INTERMEDIATE INTENSITY REGIME USING ULTRA-FAST LASER PULSES". Thesis, Université Laval, 2010. http://www.theses.ulaval.ca/2010/27640/27640.pdf.
Texto completo da fonteFailloux, Nelly. "Etude cinétique de la stabilité et de la diffusion cutanée du rétinol par spectrométrie Raman : évaluation de la cytotoxicité et du potentiel inflammatoire du rétinol et de ses dérivés". Paris 6, 2003. http://www.theses.fr/2003PA066112.
Texto completo da fonteLou, Nelson. "Couches supportées et membranes ultraminces à base de silicium : fabrication et spectrométrie raman-brillouin". Toulouse 3, 2009. http://thesesups.ups-tlse.fr/557/.
Texto completo da fonteThe improvements in Micro and now Nanoelectronic lead to the shrinking of the devices and at the same time the need to develop suitable and effective methods of characterization. Following this motion, we focused our interest on the use of terahertz sound as a matter probe at nanometric scale in inelastic scattering of light experiments. To that end, we studied Raman-Brillouin scattering of ultra thin layers of silicon which implies the interaction between localized electronic states and acoustic phonons with wavelengths in nanometric range. In the aim to study the effect of its surrounding on the Raman-Brillouin scattering of an ultra thin silicon layer, we made model systems composed of nanometric layers stacks of different materials (silicon, silicon nitride and silicon dioxide) on substrate or in membrane configuration. A high-performance Raman spectrometer, in low frequency range and coupled with an original optical input, enabled us to study the Raman-Brillouin scattering of these model systems. We systematically compared the experimental spectrums to simulations based on photo elastic model. That systematic comparison enabled us to identify of the optical and acoustic cavity functions and some criteria and a methodology to be able to analyse quantitatively the experimental data. The developed approach shows to be particularly sensitive in the face of oxide and interfacial layers whose thicknesses don't exceed two nanometres. .
Liu, Min. "Radiation-induced processes within DNA in the gas phase". Electronic Thesis or Diss., Normandie, 2023. http://www.theses.fr/2023NORMC292.
Texto completo da fonteDNA damage is generally considered to be the most common and most important type of lesions in cells caused by ionizing radiation. While DNA damage caused by ionizing radiation poses serious risks to human health, it also makes radiation therapy a powerful tool for killing cancer cells and saving lives. For these reasons, a great deal of research has focused on radiation-induced processes within DNA. However, most of this work has been carried out in the condensed phase, which cannot remove the influence of the surrounding environment. In order to investigate the consequences of direct interaction of DNA with ionizing radiation at the molecular scale, we have irradiated a self-complementary DNA sequence in the gas phase with synchrotron radiation or ion beams, and analyzed the resulting product ions by mass spectrometry. Thanks to ion mobility spectrometry, we have established that deprotonated double strands of this sequence indeed form a double helix that is stable in an ion trap, if the charge state is higher than 5-. Then, we have investigated the consequences of specific photoabsorption occurring at the DNA oligonucleotide backbone in the gas phase. By monitoring non-dissociative single electron detachment from deprotonated precursors as a function of photon energy around the phosphorus K-edge, we have identified the X-ray spectral signature of selective photoabsorption at the phosphorus atoms located only in the backbone. We also detected abundant nucleobase fragment cations resulting from multiple electron detachment and thus demonstrated the charge, energy and hydrogen transfer from the backbone to the nucleobases. In the final part of the thesis, we present the results of irradiation of the DNA oligonucleotides by carbon ions in the gas phase. We have observed similar non-dissociative single electron detachment and similarly abundant positive fragment ions after carbon ion impact as in the case of irradiation by X-ray photons. More importantly, we have successfully irradiated a helical DNA double strand in the gas phase for the first time. 70% of the resulting ionic products come from non-dissociative single electron detachment, which is much higher than the case of single strands. Therefore, direct ionization of a DNA double helix after interaction with a single carbon ion does not lead to separation of the strands, which has important implications regarding DNA damage, notably in the context of hadrontherapy
Nemausat, Ruidy. "Etude expérimentale et théorique des fluctuations thermiques quantiques des noyaux par spectroscopies d'absorption X et RMN". Electronic Thesis or Diss., Paris 6, 2016. http://www.theses.fr/2016PA066158.
Texto completo da fonteIn this thesis the impact of quantum thermal fluctuations on XANES and solid-state NMR spectra is described using an experimental and theoretical joint study. This project has two components. First, high-quality experimental data are acquired in order to observe and understand the influence of quantum vibrations in light-elements oxides. Second, a theoretical model is set up to reproduce the effects observed experimentally and describe their origin from a fundamental point of view. The developed theoretical approach is based on the density-functional theory. Within the Born-Oppenheimer and quasiharmonic approximations, the quantum thermal fluctuations of nuclei are modeled by generating atomic configurations obeying quantum statistics at finite temperature. The XANES spectra and NMR parameters are subsequently calculated in these configurations and the average results are compared with spectroscopic data at finite temperature. This approach has been validated by a joint theoretical-experimental study conducted in a series of light-element oxides, where the results were found to be in excellent agreement with the original experimental data. In addition, it is shown that the impact of the quantum fluctuations of the nuclei is influenced by the local symmetry of the probed atomic site
Bouyer, Viviane. "Etude de la transition choc-détonation du nitrométhane par spectrométrie d'émission". Phd thesis, Paris 10, 2002. http://tel.archives-ouvertes.fr/tel-00849680.
Texto completo da fonteSchwob, Lucas. "Ionisation et fragmentation de biomolécules sélectionnées en masse induites par impacts d’ions et photo-absorption". Caen, 2016. https://hal.archives-ouvertes.fr/tel-01465838.
Texto completo da fonteThis work aims at studying fundamental physical and chemical processes induced by ionizing radiation on isolated biomolecules. The first part is devoted to the development and characterization of the experimental set-up PIBALE (Plateforme d'Irradiation de Biomolécules et d'Agrégats Libres et Environnés). The goal of this apparatus is to analyze ion-induced ionization and fragmentation of biologically relevant molecular systems. The biomolecules are produced by means of an electrospray ionization source, mass-over-charge selected, bunched in an ion trap and subsequently extracted to the collision zone. Fragment cations produced during the interaction with the atomic ion beam are analyzed by time-of-flight mass spectrometry. Multi-coincidence detection of the fragments will allow describing the fragmentation kinematics. The second part of this thesis is focused on the gas phase study of a collagen peptide, collagen being the most abundant structural protein in the human body, as well as a hydrogen-bonded collagen triple-helix model. Photo-absorption experiments, from UV to soft X-rays, show that several molecular orbitals can be probed with a single photon and that a smooth transition from excitation to ionization occurs. Above the ionization threshold, the excess energy is distributed into the internal ro-vibrational degrees of freedom and induces inter- followed by intra-molecular dissociation. Thus, photon irradiation could lead to collagen denaturation by the loss of its triple-helix structure. Moreover, collagen-specific fragmentation channels have been found to be triggered by photon absorption
Enjalbert, Quentin. "Nouvel outil de quantification de biomarqueurs couplant la spectroscopie optique et de la spectrométrie de masse, la Photo-SRM". Phd thesis, Université Claude Bernard - Lyon I, 2013. http://tel.archives-ouvertes.fr/tel-01072242.
Texto completo da fonteMartin-Burtart, Nicolas. "Développement d'algorithmes d'analyse spectrale en spectrométrie gamma embarquée". Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00869554.
Texto completo da fonteSioud, Salim. "Improvement of the detection of organic environmental pollutants and comprehension of the gas-phase chemical ionization mechanism using dopant-aided vacuum ultraviolet photoionization high- resolution mass spectrometry". Electronic Thesis or Diss., Sorbonne université, 2023. http://www.theses.fr/2023SORUS527.
Texto completo da fonteInnovative analytical methods are needed to monitor these organic pollutants in response to climate change. High-resolution mass spectrometry coupled with atmospheric pressure photoionization (APPI-HRMS) associated with ultra-performance liquid chromatography (UHPLC) is a state-of-the-art tool for the analysis of non-polar aromatic molecules. Indeed, multicomponent mixtures and new dopant delivery system (piezoelectric printhead) have been developed for APPI applications to improve the ionization and detection performance of PAHs during atmospheric pressure photoionization mass spectrometry. This allowed us to separate and detect 14 of the 18 studied PAHs at low pg/µl concentrations with high mass accuracies of ≤4 ppm in 5 minutes. In addition, these innovations improved the limits of detection and quantification (LOD and LOQ) of the PAHs tested by 2 to 10 times. Secondly, in order to understand the detailed ionization mechanisms leading to the formation of radical cations ([M]+•), and to the formation of [M–H]+ ions for a class of derivatives of TPD- N-substituted, multiple experimental studies have been investigated. Thus, only one radical cation type, [M]+•, was observed for PAHs using ethanol-based multicomponent dopants. On the other hand, [M–H]+ ions for N-alkyl-TPD derivatives were observed in greater abundance under APPI conditions. In addition, the halogenated benzene-type dopant and the length of the alkyl chain (CnH2n+1), with n ≥4, influenced the formation of [M–H]+ ions
Rodesch, Pierre-Antoine. "Méthodes statistiques de reconstruction tomographique spectrale pour des systèmes à détection spectrométrique de rayons X". Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAM093/document.
Texto completo da fonteX-ray spectral tomography is a 3D visualization technique. It is based on the transmission of X-rays through object matter. It is a non-destructive technology but which irradiates the studied object/patient. X-ray tomography is mainly used in three areas: medical diagnosis, non-destructive testing (detection of defects in industry devices) and airport security (luggage screening). New technological breakthroughs in X-ray photon-counting detectors provide new perspective for improving this technique in each application field. We have developed a new reconstruction method named MLTR-ONE-STEP which enables the obtention of energetic variability of the scanned object linear attenuation coefficient. This approach belongs to the “One-Step” class because it directly reconstructs the final images from raw photon-counting detector data.Physical effects inside the detector are causing spectral distortion of the energetic spectrum. This distortion is taken into account in our reconstruction through a Detector Response Matrix. The developed reconstruction method maximizes the poissonian likelihood of the measurements with a spatial regularization Tukey term. The objectives of spectral tomography are the improvement of the image quality compared to standard tomography and the quantification of materials inside the object. We have studied the influence of regularization parameters on the final result. In practice, photon-counting detector measurements are in practice sorted in 64 energy bins. Bins are then merged in a smaller number (from 2 to 25). The influence of this binning was studied on simulated data. The MLTR-ONE-STEP was then tested on real experimental data in order to prove the feasibility of such a “One-Step” reconstruction method
Mila, Frédéric. "Contribution théorique à l'étude des propriétés structurales et vibrationnelles de surfaces et d'interfaces". Paris 11, 1987. http://www.theses.fr/1987PA112477.
Texto completo da fonteDelorme, Nicolas. "Elaboration de surfaces à mouillabilité photo-contrôlable". Phd thesis, Université du Maine, 2004. http://tel.archives-ouvertes.fr/tel-00007804.
Texto completo da fonteLa méthode d'élaboration sur surfaces polymère a consisté à fonctionnaliser la surface d'un film commercial de polypropylène par un traitement plasma CO2. La concentration surfacique des fonctions chimiques introduite sur la surface du film polymère a été déterminée en combinant, pour la première fois, les résultats de la spectroscopie des photo-électrons X (XPS) et ceux d'un dosage fluorimétrique à l'aide d'un spectromètre Raman. La voie d'élaboration utilisée permet, pour la première fois à notre connaissance, le greffage des chromophores uniquement sur l'extrême surface du matériau.
Nos résultats ont permis d'attribuer les variations réversibles de la mouillabilité des matériaux non pas à une modification de la polarité de la surface due à l'isomérisation des chromophores greffés sur la surface du film polymère, mais à une variation réversible de la morphologie de la surface due à l'isomérisation des composés azoïques diffusés dans le matériau.
Dans l'objectif d'applications en microfluidique et afin d'avoir une meilleure compréhension des paramètres influençant le photo-contrôle de la mouillabilité, nous avons mis en place plusieurs voies de préparation pour permettre le greffage d'une couche moléculaire de chromophores sur la surface silicium.
L'ensemble de nos travaux ajouté à l'analyse des résultats tirés de la littérature a permis de contribuer à une meilleure compréhension des paramètres pouvant influencer le photo-contrôle de la mouillabilité de surface de matériaux. Ainsi, pour les surfaces siliciées, le choix du chromophore est important car pour bénéficier d'une grande variation de mouillabilité, la surface doit être composée de chromophores dont les isomères possèdent une forte différence de moment dipolaire. Un autre paramètre important semble être la compacité de la couche de chromophore greffée sur la surface silicium car plus cette couche est compacte, plus la variation de mouillabilité observée est importante.
Ignasiak, Marta. "Study of the mechanism of radiation- and photo-induced oxidation of methionine containing peptides". Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112098/document.
Texto completo da fonteSeveral factors (radiation, metabolism, pollutants) lead to the generation of oxidizing free radicals in living organisms that damage all biomolecules and especially proteins. One of the protein targets is Methionine (Met). Its oxidation causes highly damaging effects, such as Alzheimer’s or prion disease. The aim of this work was to investigate the transient species and the stable products formed after radiolytic and photolytic oxidation of Met-containing peptides. The reaction of hydroxyl radicals (•OH) and 3-carboxybenzophenone triplet state with Met-residue in peptides was investigated for model compounds (Met-dipeptides) and for longer peptides (e.g. Bradykinin). Laser flash photolysis and pulse radiolysis were used to characterize short-lived transient species, while gamma radiolysis and steady-state photolysis were used for quantitative and qualitative characterization of stable products. The structural modifications induced by oxidation have been characterized by the HPLC coupled with mass spectrometry and Infrared Multi Photon Dissociation Spectroscopy (IRMPD, CLIO Free electron laser). The oxidation of investigated Met-containing compounds by •OH or 3CB* led to the formation of S-centered radical cation >S•+ on Met-residue, that were further stabilized by formation of two-centered three-electron bond (S∴Y)+ or underwent the deprotonation reaction yielding the α-(alkylthio)alkyl radicals (α-S). The oxidation of Met-containing dipeptides by •OH radicals yielded the formation of Met sulfoxide (MetSO) as a main product. Undoubtedly, the identification and characterization of MetSO in deoxygenated solutions containing catalase was a milestone in investigation of stable products. However, in some cases, other products were identified. The stable products of photolysis were adducts with 3-carboxybenzophenone moiety, resulting from radical recombination reaction. Another identified product formed during photolysis was 3CB-3CB benzpinacol photoadduct, which has similar structure to the product of BP irradiations. Identified products (MetSO and the photo-adduct) were formed from the α-S via disproportionation or reaction with 3CBH•/3CBH•⁻. The oxidation of Met-Lys-Bradykinin (MKBR) yielded formation of similar photo-adducts via sensitized reaction with the 3CB*. The •OH induced oxidation of MKBR yielded several products, e.g. the sulfoxide and hydroxylated phenylalanine. In addition, other derivatives of benzophenone (oxybenzone (OXB) and sulisobenzone (SB)) were investigated due. They are widely used in commercial sun-protecting products dp to their unique photophysical properties. However the application of sunscreens awakes controversies because some epidemiological studies indicated an increased risk of malignant melanoma for their users. Photo-instability of sunscreen filters would result in reduced protection and may produce reactive free radicals or mutagens. In addition, the reactions of the sunscreens with oxygen free radicals e.g. hydroxyl radicals are likely to arise and they were not yet sufficiently documented. Finally, the radiolytic and photolytic properties of SB and OXB were investigated using femto-and nanosecond laser flash photolysis. Pulse radiolysis studies of the oxidation of those molecules by •OH radicals were performed. The results obtained for SB and OXB were compared to several other benzophenone derivatives. The results shown the formation of excited singlet state that was deactivated efficiently via the Excited State Intramolecular Proton Transfer (ESIPT). In case of polar solvent, the formation of trace amounts phenoxyl radicals was identified, while for nonpolar media those radicals were not observed. The reactivity of UV-excited sun filters towards simple derivatives of Met was also investigated, however, this topic requires further and more detailed investigations
Panza, Fabien. "Développement de la spectrométrie gamma in situ pour la cartographie de site". Electronic Thesis or Diss., Strasbourg, 2012. http://www.theses.fr/2012STRAE043.
Texto completo da fonteThe high-resolution gamma spectrometry currently provides a powerful analytical tool for performing environmental measurements. In the context of radiological characterization of a site (natural or artificial radioactivity) and for the dismantling of nuclear installations, mapping of radionuclides is an important asset. The idea is to move a HPGe spectrometer to study the site and from nuclear and position data, to identify, to locate and to quantify the radionuclides present in the soil. The development of this tool follows an intercomparaison (ISIS 2007) where an intervention / crisis exercise showed the limits of current tools. The main part of this research project has focused on mapping of nuclear data. Knowledge of the parameters of an in situ spectrum helped to create a simulator modeling the response of a spectrometer moving over contaminated soil. The simulator itself helped to develop algorithms for mapping and to test them in extreme situations and not realizable. A large part of this research leads to the creation of a viable prototype providing real-time information concerning the identity and locality as possible radionuclides. The work performed on the deconvolution of data can make in post processing a map of the activity of radionuclide soil but also an indication of the depth distribution of the source. The prototype named OSCAR was tested on contaminated sites (Switzerland and Japan) and the results are in agreement with reference measurements
Lailliau, Maxence. "Étude expérimentale et modélisation cinétique de la combustion de composés modèles de biocarburants : Détermination d'intermédiaires par spectrométrie de masse à photo-ionisation par rayonnement synchrotron". Thesis, Orléans, 2019. http://www.theses.fr/2019ORLE3096.
Texto completo da fonteWith the depletion of fossil fuel resources, the search for new alternatives such as biofuels produced from biomass has intensified. A wide variety of compounds can be produced by treating this biomass. Ethers are one of them and can be used as additives to conventional fuels or as fuel. To this end, it is necessary to have a better knowledge of the kinetics of the oxidation of these compounds which differ from conventional fuels by the presence of oxygen atoms in their structure, making the chemistry more complex. This thesis aims to develop kinetic mechanisms of the oxidation of simple ethers based on experimental data obtained in jet stirred reactor. The oxidation of four ethers at atmospheric pressure and high pressure (10 atm) was studied over a wide range of temperatures (450 - 1250 K) under different equivalence ratios (0.5 to 4). The mole fraction profiles of the reactants, products of combustion and main stable intermediates were measured by gas chromatography, infra-red spectrometry or photoionization mass spectrometry using synchrotron radiation. The results thus obtained then served as a basis for validating kinetic mechanisms modeling the oxidation of these species whose agreement with the measurements is globally satisfactory for compounds for which few studies are available
Fraval, Kevin. "Measurement and analysis of the 241 Am (n,γ) cross section at the Cern n _TOF facility". Paris 7, 2013. http://www.theses.fr/2013PA077177.
Texto completo da fonteThe 241Am(n,g) cross section was measured at the n_TOF facility, at CERN by time of flight spectrometry. The detectors used for photon detection were C6D6 liquid scintillators. After callbration and event selection above a 300 keV threshold, the extracted histograms were corrected for dead time an efficiency using the weighting function technique. These weighting functions were calculated using simulated detectors response obtained via MCPX. All the background sources were estimated and normalized for proper subtraction to the total signal. The sample's capture yield was then calculated by dividing the net weighted count rate by the incoming neutron flux and compound nucleus excitation energy. This yield was then normalized to the capture yield of a well know isotope, namely at 4. 9 eV on 197Au. Finally, resonance analysis performed with the SAMMY code allowed the extension of the resolved resonance range to 320 eV, which is twice larger than in previous evaluations. The thermal cross section was found to be 678 +- 68 barns, and a statistical analysis was performed, together with an unresolved region analysis, up to 150 keV. The average cross section between 320 eV and 150 keV is larger than in previous estimations. Future worl should focus on reducing background to minimize the uncertainty on the thermal value, and also reducing the sensitivity to the gamma flash, in order to extend the upper limit of the unresolved range
Panza, Fabien. "Développement de la spectrométrie gamma in situ pour la cartographie de site". Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00975929.
Texto completo da fonteDouin, Stéphane. "Spectroscopie des agrégats de Van Der Waals aniline-(argon)#n et de quelques dérivés". Paris 11, 1994. http://www.theses.fr/1994PA112128.
Texto completo da fonteChabane, Abderrahim. "Visualisation d'œuvres d'art masquées". Thesis, Paris 10, 2014. http://www.theses.fr/2014PA100191/document.
Texto completo da fonteThis study deals with the diagnosis of hidden paintings by a layer of lime or another paintings.Three original methods are presented and experimentally validated the principle. First, a new excitation method of the deeper layers based on far infrared radiation λ>20 μm, which has a higher efficiency compared to the conventional method of thermal conduction excitement. The fact that the filter removes short wavelength in the heating surface of the material. The semi-transparent layer of lime in the far infrared can illuminate layers of paint directly and get thermograms revealing hidden patterns.We also studied the transmission of the layers of paint in the far infrared by Fourier transform spectroscopy. The painting present in the far infrared 30> μm areas obsorption witch caracteristic of functional groups. Also the measurement of total emission in the far infrared at room temperature allows their identification.Finally, we introduced a new approach for diagnosing murals hidden by a layer of lime based on measuring the time of flight of photons backscattered ballistic collected by a streak camera with a resolution of 2 ps
Deloule, Sybelle. "Développement d'une méthode de caractérisation spectrale des faisceaux de photons d'énergies inférieures à 150 keV utilisés en dosimétrie". Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112273/document.
Texto completo da fonteIn the field of dosimetry, the knowledge of the whole photon fluence spectrum is an essential parameter. In the low-to-medium energy range (i.e. E<150 keV), the LNHB possess 5 X-ray tubes and iodine-125 brachytherapy seeds, both emitting high fluence rates. The performance of calculation (either Monte Carlo codes or deterministic software) is flawed by increasing uncertainties on fundamental parameters at low energies, and modelling issues. Therefore, direct measurement using a high purity germanium is preferred, even though it requires a time-consuming set-up and mathematical methods to infer impinging spectrum from measured ones (such as stripping, model-fitting or Bayesian inference…). Concerning brachytherapy, the knowledge of the seed’s parameters has been improved. Moreover, various calculated X-ray tube fluence spectra have been compared to measured ones, after unfolding. The results of all these methods have then be assessed, as well as their impact on dosimetric parameters
Lavoie, Jean-Philippe. "Production of pure ion beams by laser ionization and a fast release RFQ". Thesis, Université Laval, 2010. http://www.theses.ulaval.ca/2010/27202/27202.pdf.
Texto completo da fonteDziri, Samir. "Etudes expérimentales et simulations Monte Carlo en spectrométrie γ : correction des effets de cascade et de matrice pour des mesures environnementales". Phd thesis, Université de Strasbourg, 2013. http://tel.archives-ouvertes.fr/tel-01062384.
Texto completo da fonteGey, Guillaume. "Etude de noyaux riches en neutrons dans la région du coeur doublement magique de ¹³²Sn". Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENY033/document.
Texto completo da fonteEvolution of nuclear structure in the vicinity of the doubly magic nuclei 132Sn will be discussed in this work, through the spectroscopy of 136Sb, 136Sn and 138Sn isotopes. Several Sb and Sn known isotopes beyond the Z=50 and N=82 shell closures will be briefly presented in the first chapter, aswell as some of the problems arising from the current shell model descritpion of nuclei in this region. Reader will also find in the same chapter a brief description of the most important tools needed to understand such calculations. Excited state of 136Sb have been populated at the Institut Laue-Langevin (Grenoble) through thermal neutron-induced fission on a 241Pu target. Fission fragments produced were separated with the Lohengrin mass spectrometer. Conversion electrons and gammas from 136Sb were measured and confirmed the previously proposed schemed. A new 31(7) ns isomer has been measured and assigned to the 4- state. Details of the experiment and analysis are presented in the first part. The second part is devoted to the 136,138Sn isotopes, produced via in-flight fission of 238U on a 9Be target at the RIBF of the RIKEN (Tokyo). Mass separators BigRIPS and ZDS allowed separation and identification of produced fragments, before implantation in the higly segmented silicon detector WAS3ABi surrounded by the germanium array EURICA. The first energy measurement of the 6+ -> 4+, 4+ -> 2+ and 2+ -> 0+ transitions has been performed for each of the 136,138Sn isotopes, aswell as an 46(7) and 219(58) ns half-life for the 6+ state of the 136Sn and 138Sn respectively
Almadori, Yann. "Fonctionnalisation non-covalente de nanotubes de carbone mono-feuillets : étude du confinement de molécules photo-actives et intercalation de rubidium". Phd thesis, Université Montpellier II - Sciences et Techniques du Languedoc, 2013. http://tel.archives-ouvertes.fr/tel-00997533.
Texto completo da fonteBoireau-Adamezyk, Elise. "Spectroscopies vibrationnelles (MCR et ATR-FTIR) et Chromatographie Liquide couplée à la Spectrométrie de Masse Haute Résolution (LC-HR-MS) : Outils d’investigation in vivo de l’impact du vieillissement cutané sur le Stratum Corneum aux niveaux tissulaire, supra-moléculaire et moléculaire". Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112070/document.
Texto completo da fonteSkin is the external surface defining the human body in space. Its outer-most layer is a thin biological membrane, called Stratum Corneum(SC), that protects the internal organs from desiccation as well as chemical or mechanical external aggressions. The present thesis aimsin a first step, to summarize the current knowledge regarding the effects of intrinsic and extrinsic aging on SCphysiology,based on available literature. The experimental part addresses the gaps in our understanding of the effects of chronological aging and photoaging on the SC barrier function and hydration, using traditional methods (such as trans epidermal water loss and skin conductance) as well as more advanced ones (vibrational spectroscopies, liquid chromatography in normal phase tandem mass spectrometry high resolution with an APCI source and an Orbitrap detector. As these methods are non-invasive, all studies have been carried out in vivo. The evolution of the barrier function has been studied at the tissular, molecular and supramolecular levels using confocal Raman micro-spectroscopy and infrared spectroscopy. Then the link between the intrinsic aging and the ceramides of the intercorneocytary lipid matrix has been studied by liquid chromatography tandem mass spectrometry. The discriminant molecules between young and old population have been identified by a chemometric analysis. The evolution of cutaneous hydration at the tissular, molecular and supramolecular level has also been investigated. The variations in the NMF composition and the SC water content have been studied by Raman spectral descriptors. Moreover, the structural variations of water molecules impacting the supramolecular organization of the lipid structures have been evaluated. Chronological aging and chronic exposure to environmental factors mildly affect SC barrier function and hydration levels. However, the processes controlling these properties are affected by aging in a site-dependent fashion
Berthelot, Vivien. "Biochimie analytique de complexes de réparation de l'ADN : élaboration d'un système analytique intégré". Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112386/document.
Texto completo da fonteIn eucaryotic cells, DNA double-strand breaks are repaired through two main pathways : the homologous recombination and the non homologous end joining . Altough these pathways are well characterized, two particular aspects of the repair remain poorly understood :- If two separated pathways may occur in the cells, which mechanism(s) govern the choice of the pathway that will ultimately lead to the repair ?- If the double-strand break is induced by ionizing radiations – as those employed in anti-cancerous radiotherapy – how does the repair occur if the DNA ends at the edge of the break are not compatible with a direct ligation ? A proper knowledge of the proteins involved in this repair would allow the development of additives, useful to increase the efficiency of the radiotherapy.To investigate these questions, we designed a new analytical system allowing : 1) the specific recruitment of DNA double-strand break repair complexes on home-made chromatographic phases, 2) the separation of these complexes in a non-denaturing polyacrylamide gel and their subsequent visualization and 3) their biochemical characterization.The methodology developped in this work has been focused on the following points : 1) we designed and implemented a chromatographic system allowing the distinction between proteins recruited onto duplex DNA oligonucleotide with free DNA ends (mimicking DNA double-strand breaks) and proteins fixed onto the internal sequence of the same oligonucleotides ; 2) we adapted to our problematic a methodology of non-denaturing electrophoresis thus allowing the separation of the purified complexes while guaranteeing their integrity during the migration, 3) we also determined their composition by mass spectrometry after their visualization.The biochemical study has shown that the purified complexes were still functionnal, that is they were able to efficiently ligate two oligonucleotides. The study of the data provided by the mass spectrometry analysis of independant experiences proved that the complexes belonged to the DNA physiology and were especially representative of the diversity of the DNA repair pathways.Interestingly, we observed that some of the protein specifically recruited onto the the double-strand breaks were not known to be involved in the DNA repair (nucleotide synthesis, checkpoint, DNA topology, cytoskeleton).The rôle of these proteins should be characterized in cellulo especially with siRNA. On the other hand we will also use the methodological development described above to study the repair mechanisms of radio-induced DNA double-strand breaks occuring in the irradiated tumorous cells. To achieve this study we will elaborate new chromatographic phases with pre-irradiated oligonucleotides
Goutaland, François. "Processus multiphotoniques, défauts ponctuels et mécanismes de leur formation dans les fibres optiques : étude par spectroscopie laser". Saint-Etienne, 1998. http://www.theses.fr/1998STET4021.
Texto completo da fonteNGUYEN-THI, Van-Oanh. "SPECTROSCOPIE ET STABILITE DES HYDROCARBURES AROMATIQUES POLYCYCLIQUES DANS LES CONDITIONS DU MILIEU INTERSTELLAIRE". Phd thesis, Université Paris Sud - Paris XI, 2003. http://tel.archives-ouvertes.fr/tel-00005244.
Texto completo da fonteKnafo, Laurent. "Association entre les produits issus de la dégradation de la vitamine C, dépendante du H₂O₂, et le métabolisme des lipides hépatiques". Thèse, 2005. http://hdl.handle.net/1866/15295.
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