Dissertationen zum Thema „Spectroscopie TeraHertz en phase gazeuse“
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Decker, Jean. „Analyse TeraHertz sur site en temps réel des composés réglementés à l’émission atmosphérique en phase gazeuse du Centre de Valorisation Énergétique de la Communauté Urbaine de Dunkerque“. Electronic Thesis or Diss., Littoral, 2024. http://www.theses.fr/2024DUNK0696.
Der volle Inhalt der QuelleIncineration with energy recovery is one of the main treatment methods for municipal waste. The residues and emissions generated by combustion generally present an environmental and health risk. The constant evolution of regulations is tending to control emissions more and more strictly, by extending standards to new substances and lower and lower emission thresholds. This development is only possible thanks to the development of measuring instruments. High-resolution THz spectroscopy offers the advantage to detect a large number of polar compounds at trace level, with exceptional selectivity enabling unambiguous detection without any prior information about the sample. These advantages make it a very interesting and complementary alternative to currently developed techniques. The aim of this thesis work was to demonstrate and evaluate the capacity of THz spectroscopy to be used as an instrument for real-time diagnosis and monitoring of compounds of environmental interest on industrial sites. The CVE of the Dunkirk Urban Community offered to take up this challenge. A spectrometer based on the use of a frequency multiplication chain has been developed, enabling the detection of most of the compounds regulated in waste incineration, in the single frequency band of 530-620 GHz covered by a single stage. The detection limits obtained are compatible with regulatory emission limit values. The installation of the instrument on site demonstrated the ability of spectroscopy to carry out real-time quantitative multi-component in-situ monitoring. Continuous measurements of SO₂ and CO over more than 24 hours were carried out at the CVE and comparison of the results with those of two certified infrared instruments (an automated measurement system and a portable analyser) showed excellent agreement. It should be noted that a frequency-modulated line profile model has been developed for the purpose of real-time relative quantification without recourse to calibration standards. To increase the instrument's sensitivity, the preconcentration technique was coupled to the spectrometer. Measurements were carried out over complete sampling and analysis times of no more than ten minutes, making it possible to measure various COVs in atmospheric emissions from the CVE, such as formaldehyde, methanol and acetone, at sub-ppm concentrations. We have thus demonstrated the ability of THz spectroscopy to individually detect and discriminate COVs semi-continuously on site. Such an instrument could therefore be used for process and emission measurements, as well as for environmental and ambient air applications
Elmaleh, Coralie. „Développement d’un prototype ultrasensible d’analyse de gaz dans le domaine submillimétrique“. Electronic Thesis or Diss., Littoral, 2024. http://www.theses.fr/2024DUNK0698.
Der volle Inhalt der QuelleThis thesis explores the technological development of a spectroscopic experiment in the submillimeter range, also known as Terahertz (THz). This spectral band stands out for its ability to precisely resolve molecular doublets, enabling clear and precise identification of complex gas mixtures, even when other wavelengths might fail.Although the THz region offers exceptional resolving power, spectrometers operating in this region often face sensitivity challenges due to the development of technology in this band. Thanks to an innovative approach, we have implemented the first Cavity Ring-Down Spectroscopy (CRDS) experiment capable of quantifying compounds to ppb precision. The study is concentrated between 550 GHz and 650 GHz, a window of the THz spectrum that not only offers unrivalled resolution and molecular sensitivity, but also possesses the ability to penetrate non-conducting materials while being non-ionizing. These properties position this technology at the cutting edge of analysis tools, promising a plethora of applications, from fundamental research to industrial applications
REMPP, MURIEL. „Reactivite en phase gazeuse de cations radicaux metastables ,-bifonctionnels“. Palaiseau, Ecole polytechnique, 1998. http://www.theses.fr/1998EPXX0004.
Der volle Inhalt der QuelleTabarin, Thibault. „Dynamique et conformation de biomolécules en phase gazeuse“. Lyon 1, 2007. http://tel.archives-ouvertes.fr/docs/00/19/87/49/PDF/These_T.Tabarin_Dedie.pdf.
Der volle Inhalt der QuelleWe have developed a new experimental set-up which couple a quadrupole ion trap mass spectrometer with a tuneable UV-Visible laser OPO. This thesis’s work deals with the optical properties and the photofragmentation of amino acids, peptides, DNA and silver cluster tryptophan complexes in gas phase. In the case of peptides, the UV excitation of chromophores in the systems leads to a specific fragmentation which can be controlled by laser wavelength. The fragmentation schemes obtained after laser excitation depends on the photo-induced charge transfer and can be linked to the system’s geometry. The optical spectra of the silver cluster tryptophan complexes supported by TD-DFT calculations allow an elaborate study of the electronics excitation, charge transfer and relaxation in a hybrid metal biomolecule system. The production and use of the radical fragment produce by photofragmentation or by photodetachment are also discussed and exemple on peptides and DNAs are further illustrated
Cirtog, Manuela. „Caractérisation des complexes hydratés d'intérêt atmosphérique par spectroscopie infrarouge en phase gazeuse“. Paris 6, 2011. http://www.theses.fr/2011PA066701.
Der volle Inhalt der QuelleSeydou, Mahamadou. „Structures en phase gazeuse et en phase liquide de systèmes moléculaires chargés d'intérêt biologique“. Paris 13, 2008. http://www.theses.fr/2008PA132006.
Der volle Inhalt der QuelleThis work presents the study of the acetylcholine neurotransmitter and its agonists, nicotine and muscarine through infrared spectroscopy. This study has been conducted both in gas-phase and aqueous phase. The used method for the isolated molecules is infrared multiphoton dissociation (IRMPD) coupled to mass spectrometry with the radiation isued from the free electron laser CLIO. For molecules in acid aqueous phase, Fourier-transform spectroscopy has been employed. The experimental results have been interpreted first trough a systematic conformational search at different levels of quantum chemistry followed by optimization of geometries and determination of vibrational frequencies. The emphasis has been set upon the search of pharmacophores. The conforntation between theory and experments has allowed a quantitative evaluation of structural modifications as well as the switch from the inactive to the bioactive form of nicotine due to the progressive addition of explicit water molecules
Marcinkiewicz, Michal. „Terahertz Spectroscopy of Topological Phase Transitions in HgCdTe-based systems“. Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTS068/document.
Der volle Inhalt der QuelleThis thesis presents an investigation of different topological phases in mercury-cadmium-telluride (HgCdTe or MCT) based heterostructures. These solid state systems are indeed a perfect playground to study topological states, as their band structure can be easily varied from inverted to non-inverted, by changing internal or external parameters.If a system has an inverted band ordering, its electronic structure has a non-trivial topology. One cannot change its topological order without closing the band gap, which is inevitably accompanied with the appearance of massless particles in the bulk. A system, that has an inverted band structure and a finite gap in which the Fermi level is positioned, is called a topological insulator. These novel materials are insulators in the bulk, but host gapless metallic states with linear dispersion relation at boundaries, protected against disorder and backscattering on non-magnetic impurities. These states arise at the interfaces between materials characterized by a different topological order. A 2D topological insulator is thus characterized by a set of 1D spin-polarized channels of conductance at the edges, while a 3D topological insulator supports spin-polarized 2D Dirac fermions on its surfaces.The 2D and 3D massless fermions have already been demonstrated experimentally in HgCdTe-based heterostructures. However, the topological phase transitions during which the massless particles appear remain barely explored. The HgCdTe band structure can be tuned from inverted to non-inverted using chemical composition, pressure, temperature, or quantum confinement. These parameters therefore allow to probe the system in the vicinity of different topological phase transitions. In this thesis, the use of temperature as continuous band gap tuning parameter allows to study the appearance and the parameters of semi-relativistic 2D Dirac and 3D Kane fermions emerging at the points of phase transitions.The systems investigated were Hg$_{1-x}$Cd$_x$Te bulk systems and HgTe/CdTe quantum wells characterized by an inverted and regular band order, and strained HgTe films which can be considered as 3D topological insulators with a residual quantum confinement. All these systems exhibit topological properties, and the experimental results are interpreted according to theoretical predictions based on the Kane model. This thesis is complemented by an overview and the preliminary results obtained on a different compound -- a InAs/GaSb broken-gap quantum well, which was also identified as a topological insulator. The structures were studied by means of terahertz and mid-infrared magneto-transmission spectroscopy in a specifically designed experimental system, in which temperature could be tuned in a broad range
Hui, Renjie. „Dissociation par capture d'électrons peptides en phase gazeuse : mécanisme et application en analyse protéomique“. Palaiseau, Ecole polytechnique, 2012. http://www.theses.fr/2012EPXX0002.
Der volle Inhalt der QuelleLafarge, Patricia. „Couplage chromatographie en phase gazeuse-spectrométrie de masse : principe, réalisation, pratique et intérêt analytique“. Paris 5, 1988. http://www.theses.fr/1988PA05P048.
Der volle Inhalt der QuelleLamarre, Nicolas. „Photoexcitation et relaxation de cyanopolyynes en phase gazeuse dans le domaine de l'ultraviolet du vide“. Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS167/document.
Der volle Inhalt der QuelleThis PhD thesis presents essentially an experimental work dealing with gas-phase molecular physics with astrophysical applications. The goal of the PhD is the study of the photoexcitation and relaxation of cyanopolyyne molecules that have been detected in different interstellar objects (molecular clouds, comets), and in planetary atmospheres (e.g. Titan). These molecules contribute to the carbon chemistry of these media by interacting with the interstellar radiation or with the solar flux in the vacuum ultraviolet range (VUV). The excited electronic structure of neutral cyanopolyynes was studied by absorption spectroscopy with a VUV Fourier-transform spectrometer. These experiments allowed us to identify the Rydberg states, and to measure the absolute photoabsorption cross section.Among the different open relaxation processes following a VUV photoexcitation, ionisation and dissociative ionisation have been investigated in detail using SOLEIL synchrotron radiation or laser sources of Centre Laser de l’Université Paris-Sud. Data on the ionisation potentials toward the first electronic states, vibrational frequencies, vibronic couplings, etc. were obtained on cyanopolyyne cations with the use of threshold photoelectron spectroscopy and zero-kinetic-energy photelectron spectroscopy. Finally, cationic species created by dissociative ionisation of cyanopolyynes were detected by mass spectrometry. The threshold energies were measured and the formation channel of these fragments was determined with the help of DFT calculations performed by a collaborator
Robin, Dorothée. „Réactions unimoléculaires des cations ou cations radicaux hétérocycliques et oxygénés en phase gazeuse“. Paris 11, 1986. http://www.theses.fr/1986PA112306.
Der volle Inhalt der QuelleRaffin, Patrick. „EPVOM de GaAs : Analyse in-situ de la phase gazeuse par spectrométrie Raman“. Lyon 1, 1989. http://www.theses.fr/1989LYO10070.
Der volle Inhalt der QuelleMacaluso, Veronica. „Modélisation théorique de la dissociation induite par collision en phase gazeuse de biomolécules“. Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLE024/document.
Der volle Inhalt der QuelleIn the present thesis, we focus on the study of the collision induced dissociation (CID) of biomolecules. CID is a well known mass spectrometry (MS) fragmentation technique which aim is the dissociation of ions through the impact with an inert buffer gas. The collisional translational energy is converted in internal energy of the ion that can thus dissociate. CID is thus widely used in MS in order to identify or quantify one or more species through detection of the mass over charge ratio of the fragments products.Reactivity and kinetics of chemical reactions are generally studied theoretically through the research of the stationary points along the reaction coordinate. It is thus, possible, to identify the reaction minimum energy path or potential energy surface (PES). Another possibility is to perform chemical dynamics simulations, which allow to explore the reactivity of one specie without the knowledge of the products, that is a crucial point for larger molecules. Moreover, to interpret MS it is important to have a fundamental understanding of the ion’s fragmentation dynamics and important information can be recovered with simulations. In the present work, we have studied and developed physical models to address the study of complex and flexible biomolecules, like amino-acids and peptides.Once the ion is excited by single-collision, the translation-to-vibration energy transfer can be followed by a statistical internal vibrational energy redistribution (IVR) of the ion and typical statistical products are obtained. On the other hand, the collision can cause localization of the energy and a fast excitation, giving different products than those observed after an IVR. In particular a limit situation is when the ion fragments right after the collision with the gas. In order to recover these (less or fully) non-statistical fragmentations it is important to model the collision, which can be done performing explicit collision chemical dynamics. However, this activation way in simulations is limited in the time-scale (~ 10-15 ps). Statistical internal energy (or thermal) activation chemical dynamics can be used to obtain longer time scale and statistical reactivity. Moreover, observing the population decay versus the time it is possible to obtain the global and single pathways rate constants. Both activation modes have been applied to study the reactivity of the di-proline anion, the two doubly charged tri-peptides TIK(H+)2 and TLK(H+)2 and the L-Cysteine sulphate anion. In particular for the study of this last system we used our understanding of simulations to interpret experiments done with different set-ups
Huguet, Patrice. „Caractérisation d'une phase gazeuse en cours de réaction par effet Raman spontané“. Montpellier 2, 1992. http://www.theses.fr/1992MON20083.
Der volle Inhalt der QuelleChin, Wutharath. „Paysage conformationnel de petits modèles de peptides en phase gazeuse : Spectroscopie UV/ IR et approche théorique“. Phd thesis, Université Paris Sud - Paris XI, 2005. http://tel.archives-ouvertes.fr/tel-00158069.
Der volle Inhalt der QuelleLa spectroscopie UV permet de détecter les conformères les plus stables formés dans la détente, tandis que la spectroscopie dans le proche IR (vibrations d'élongation NH et CO, et de déformation NH) donne accès à leur réseau de liaisons hydrogène.
L'attribution finale des conformères observés est réalisée par comparaison avec les spectres issus des calculs de chimie quantique (théorie de la fonctionnelle de la densité) pour des conformations présentant un réseau de liaisons hydrogène compatible avec l'expérience, permettant en retour de valider les calculs réalisés.
Cette synergie expérience/théorie nous a ainsi permis de montrer l'existence d'une compétition entre deux grandes familles conformationnelles possédant des signatures spectroscopiques distinctes. La première consiste en une juxtaposition de préférences
conformationnelles locales autour de chaque résidu, caractérisées par des liaisons hydrogène reliant des groupements amides CO-NH proches dans la séquence. La deuxième famille est représentée par les structures secondaires, stabilisées par des liaisons hydrogène reliant des groupements amides plus éloignés.
En les isolant et les caractérisant pour la première fois en phase gazeuse, nous avons montré que la formation des structures secondaires typiques de la biologie telles que des coudes beta et des hélices 3-10 était bien une propriété intrinsèque de ces molécules.
Platzer, Dominique. „Spectroscopie de photoionisation d’atomes et molécules en phase gazeuse aux échelles de temps femtoseconde et attoseconde“. Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASP088.
Der volle Inhalt der QuelleIn this work are studied atomic and molecular systems in the gas phase using time-resolved electron pump-probe spectroscopy on the femtosecond (1 fs = 10⁻¹⁵ s) and attosecond (1 as = 10⁻¹⁸ s) timescales on the SE1 beamline of the ATTOLab platform. First, the femtosecond dissociation of methyl iodide following the absorption of one UV photon was investigated by Auger spectroscopy and multiphoton ionization (ATI-IR). In the latter case, a relaxation dynamic with 75 fs caracteristic time was evidenced for the part of the nuclear wavepacket confined to small internuclear distances. Second, the attosecond ionization dynamics of argon were studied over a large spectral range including Cooper minima. This study required: (i) a coherent light source in the extreme ultra-violet (photon energy in the 10-100 eV range) based on high harmonic generation and producing attosecond pulse trains, and (ii) an electron interferometry technique giving access to the spectral phase of the photoemitted wavepackets. The latter are used to extract the attosecond photoemission time delays that can be interpreted as the time necessary for the electron to escape from the atomic potential. Strong variations of the time delays were observed between the 3s and 3p valence shells, revealing important electronic correlation effects, like the presence of shake-up ionization channels. To be able to reconstruct the complete movie of the photoionization process, one needs to add spatial information to the spectral/temporal measurements. Two-photon resonant ionization of helium through the 1s3p state was then studied, using a velocity-map imaging (VMI) spectrometer instead of the angularly-integrating magnetic-bottle electron spectrometer used in the previous studies. An extremely fast spectral phase shift was measured, quite homogeneously up to 45° emission angles, thus giving a more complete view of the process. Finally, a new VMI spectrometer was designed, built and installed on the beamline. Its main specifications (energy range and resolution) were optimized for attosecond spectroscopy, mainly through the development of a new electrostatic lens
Baco, Franck. „Caractérisation des distillats pétroliers par couplage chromatographie en phase gazeuse et détection par émission atomique“. Lyon 1, 1997. http://www.theses.fr/1997LYO10123.
Der volle Inhalt der QuelleDrewnowski, Tomasz. „Application de la thermolyse éclair en phase gazeuse dans la synthèse de nouvelles jonctions hétérocycliques“. Pau, 2008. http://www.theses.fr/2008PAUU3004.
Der volle Inhalt der QuelleThe main goal of this work, was to synthesize and study the electronic structure of 6-thioxocyclohexa-2,4-dienylidenethioketene (or, its open form-thiobenzopropiothionolactone) obtained using Flash Vacuum Thermolysis (FVT) method. Two different approach for identification of this highly reactive intermediate has been applied. First, the chemical trapping on a "cold finger" with classical spectral characterization has been carried out. Second, the FVT oven inside the UV-photoelectron spectroscopy apparatus has been used to the direct follow-up of thermal decomposition of different precursors judiciously selected. For all stating compounds, as well as for products and transients, quantum calculations of ionization potentials by three different methods (OVGF/6-311G(d,p); DFT: B3LYP/6-311G(d,p) and so-colled "corrected" IP) after full geometrical parameters optimisation have been performed. In the case of 4H-3,1 -benzoxatin-4-thione analogs the Schönberg-Newman-Kwart rearrangement has been evidenced as a first step of FVT transformation and confirmed by the thermolysis of 3H- izobenzofuran-1-thione analog in the independent experiments. Increasing of the temperature to 650° resulted in the elimination of thioformaldehyde molecule and formation of thiobenzopropiolactone. Subsequent elevation of the temperature prompted presumably the cleavage of the latter to its open isomer 6-thioxocyclohexa-2,4-dienylideneketene (at 680°), which in higher temperature (700°) eliminated the CO molecule and underwent a Wolff-type ring contraction to 6- fulvenethione. Flash vacuum thermolysis of 4H-1,3-benzodithiin-4-thione resulted in the formation of phenanthro[9,10-c]-1,2-dithiete and 3H-1,2-benzo-dithiole-3-thione. The mecanism of this reaction includind the formation of thiobenzopropiothionolactone as an intermediate has been postulated
El-Rabii, Hazem. „Etude de l'allumage par laser de mélanges en phase liquide dispersée et gazeuse“. Phd thesis, Ecole Centrale Paris, 2004. http://tel.archives-ouvertes.fr/tel-00008582.
Der volle Inhalt der QuelleL'objectif du présent travail est d'effectuer une étude paramétrique de ce mode d'allumage pour des mélanges en phases liquides dispersées et gazeuses, ainsi que d'apporter une contribution à la compréhension des phénomènes physiques liés au claquage optique, aussi bien dans l'air que dans les mélanges inflammables. Les plasmas rencontrés sont caractérisés, en termes de concentrations et de températures électroniques, avant d'aborder l'étude paramétrique du claquage dans l'air et de l'allumage des mélanges gazeux et diphasiques inflammables. L'importance de la dynamique induite par l'étincelle laser sur l'évolution de la structure et de la forme du noyau d'allumage est considérée. Le rôle des aberrations, et en particulier de l'aberration sphérique, est soigneusement étudié du point de vue théorique. Des conclusions importantes sur l'interprétation des résultats expérimentaux sont dégagées. La détermination des seuils de claquage, ainsi que l'identification des processus déterminants, sont analysés à la lumière d'un modèle basé sur la détermination de l'évolution de la concentration d'électrons libres dans le volume focal. Finalement, la faisabilité de l'allumage laser à la sortie d'un injecteur prévaporisé, prémélangé en régime pauvre est démontrée.
Compagnon, Isabelle. „Mesure de dipôle électrique en phase gazeuse ; application aux agrégats et aux biomolécules“. Phd thesis, Université Claude Bernard - Lyon I, 2003. http://tel.archives-ouvertes.fr/tel-00006704.
Der volle Inhalt der QuellePecheyran, Christophe. „Détemination des formes chimiques des métaux en phase gazeuse dans différents environnements atmosphériques“. Bordeaux 1, 1997. http://www.theses.fr/1997BOR10570.
Der volle Inhalt der QuelleLemierre, Virginie. „Synthèse et caractérisation en phase gazeuse de germylènes. : Etude théorique et expérimentale par spectroscopie photoélectronique à rayonnement UV“. Pau, 2004. http://www.theses.fr/2004PAUU3033.
Der volle Inhalt der QuelleThis thesis discusses the electronic structure and the influence of substituant groups in a,a'-di-homo- and di-hetero-substituted germylenes. Part one presents hydrogen and carbon substitued germylene :GeH2 or :GeR2 (R=H, Me, Ph or Mes). We deduce from measured ionisation potentials that ionisation of the lone pair of Ge depends on both the electronic structure of the substituant and on the geometries of the molecules. The second part deals with the evaluation of the effect on electronic structure of nitrogen, oxygen or sulphur atom heteroleptic (dis-symmetric) substitution of N, O and S a, a'-disubstituted germanediyls (cyclic germylenes). Analysis of the SPE results shows that stabilisation depends on the p-donation of heteroatom lone pairs to germanium 4pp vacant orbitals and the on the s-withdrawing effect of these atoms. The study of divalent heteroleptic species Lø(X)Ge(II) with X=Cl, I, Me or OMe stabilized in the monomer state by using of b-diiminate bidentate ligand (Lø) is developed in this third chapter. In the fourth part of this thesis the performance of different methods of calculating IPs were analysed and compared
Simon, 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.
Der volle Inhalt der QuelleThis 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
Collet, David. „Spectroscopie laser haute sensibilité des ions moléculaires en phase gazeuse : étude des ions N2+, Cl2+ et HBBr+“. Lille 1, 2000. https://pepite-depot.univ-lille.fr/RESTREINT/Th_Num/2000/50376-2000-278.pdf.
Der volle Inhalt der QuelleBisch, Christophe. „Etude d'un réacteur destiné à caractériser par effet Raman spontané la phase gazeuse dans le procédé de dépôt chimique en phase vapeur“. Perpignan, 1996. http://www.theses.fr/1996PERP0235.
Der volle Inhalt der QuelleBouakil, Mathilde. „Étude de la conformation et de la dynamique conformationnelle de molécules biologiques en phase gazeuse“. Thesis, Lyon, 2020. http://www.theses.fr/2020LYSE1145.
Der volle Inhalt der QuelleProtein functions in living organism are governed by their 3D structure. This thesis focuses on the characterization of protein conformation and conformational dynamics by means of mass spectrometry, and participates to the development of tools for structural biology. Mass spectrometry coupled to time resolved optical spectroscopy can set light on mechanisms associated with conformational dynamics: photon absorption, electronic relaxation, photo-induced charge transfer, etc. Experimental approaches combining mass spectrometry, optics and molecular biology (protein expression, gel electrophoresis, circular dichroism, etc.) will be presented in the first section of this manuscript. This thesis work was initiated by the study of the photo-induced activation of the chromophores which were used, at ILM, for action-FRET and more generally for the exploration of the proteins structure. The mechanisms of photon absorption and non-radiative relaxation were studied for chromophores grafted on multiple peptides. We then probed the photo-induced intramolecular charge transfer and associated conformational dynamics in series of small peptides in order to understand the influence of the system size and composition on its structural dynamics. The latter experiment required the implementation of a two-color pump-probe setup. Finally, we used ion mobility spectrometry to probe and investigate the conformational space and dynamics of the PUMA peptide, ubiquitous in mammalian organisms and associated to the regulation of apoptosis
Perlot, Nicolas. „Caractérisation des fluctuations du signal dans les communications optiques par modulation d'intensité et détection directe à travers le canal atmosphérique turbulent“. Valenciennes, 2005. https://ged.uphf.fr/nuxeo/site/esupversions/85329049-3099-4b6b-99da-ed87313b72f1.
Der volle Inhalt der QuelleLaser free-space communications are now able to compete with radio communications. However, optical communications through the atmosphere still suffer from significant drawbacks. In particular, atmospheric optical turbulence, which consists of variations of the refractive index, must be considered as random. Turbulence induces phase and intensity fluctuations in the propagating wave and can cause severe degradations of the system performance. The purpose of this thesis has been to characterize the turbulence-induced fluctuations of the received optical power, also called scintillation. These fluctuations depend on parameters such as the path length, the turbulence strength, the beam shape or the size of the receiving aperture. Theoretical results are derived from the Kolmogorov model of turbulence but different approaches leading to different results are available. Distribution and temporal spectrum of the received optical power serve as inputs to the direct-detection receiver model
Lucas, Bruno. „Spectroscopie infrarouge couplée à la spectrométrie de masse pour la caractérisation en phase gazeuse de petits systèmes moléculaires neutres ou protonés“. Paris 13, 2004. http://www.theses.fr/2004PA132014.
Der volle Inhalt der QuelleGuillaumont, Sébastien. „Etude de la réactivité en phase gazeuse des ions Pb2+envers les acides nuléiques : approches expérimentale et théorique“. Evry-Val d'Essonne, 2006. http://www.theses.fr/2006EVRY0004.
Der volle Inhalt der QuelleThe goal of this work is the comprehension of the gas-phase reactivity of metallic cation Pb2+ towards nucleic acids by using jointly experimental (mass spectrometry) and theoretical (molecular modeling) techniques. This work has been carried out by gradually increasing the size of the systems studied. First of all, we have examined the reactivity of Pb2+ ions towards natural and modified nucleobases. Results obtained have allowed a better understanding of the reactivity of nucleosides, and then notably addresses the influence of the sugar moiety. Finally, results about the experimental study of reactivity of Pb2+ ions towards mononucleotides and the role of the phosphate group in the formation of the complexes are gathered in the last chapter
Lavigne, Renaud. „Spéciation des ultra-traces d'étain par couplage chromatographie en phase gazeuse-spectométrie d'absorption atomique après génération d'hydrures“. Pau, 1989. http://www.theses.fr/1989PAUU3002.
Der volle Inhalt der QuelleBoyrie, Fabrice. „Modélisations pour l'analyse de la structure et de la réactivité d'organométalliques en phase gazeuse“. Phd thesis, Université Paris Sud - Paris XI, 2005. http://tel.archives-ouvertes.fr/tel-00117007.
Der volle Inhalt der QuelleLes surfaces de potentiel associées à la réactivité sont modélisées dans le cadre de la théorie des hamiltoniens effectifs, et l'on s'intéresse plus particulièrement à l'addition oxydante d'un ion LnM+ sur une liaison H-H. L'idée est de bâtir un hamiltonien effectif associé aux électrons actifs, c'est-à-dire à l'insertion de M+ dans la liaison H-H, puis d'utiliser une approche de type champ de ligands pour traiter l'effet des ligands spectateurs (Ln). L'originalité de l'approche réside surtout dans la construction du hamiltonien effectif associé à M+ + H-H. Il est bâti à partir de potentiels à deux corps associés à M+-H et H-H, dérivés de calculs ab initio sur les états électroniques de valence de ces fragments. En utilisant une correction appropriée pour les termes à trois corps, notre modèle localise correctement les points stationnaires de M+ + H2, et la précision sur leurs énergies relatives est de l'ordre de 20 kJ/mol.
La seconde partie porte sur le développement d'un modèle cinétique pour interpréter l'efficacité de fragmentation d'ion induite par une absorption multiphotonique infrarouge en phase gazeuse, phénomène exploité pour obtenir le spectre IR d'ions formés en spectrométrie de masse. Les paramètres de notre modèle sont associés à la focalisation et à la structure temporelle du laser, ainsi qu'à la trajectoire et aux paramètres physico-chimiques des ions. La très bonne simulation de plusieurs expériences permet de mieux comprendre les phénomènes observés et constituera un guide précieux pour les prochaines campagnes d'expériences.
Triki, Meriam. „Cavités optiques de haute finesse pour la mesure de composés à l'état de trace en phase gazeuse“. Phd thesis, Université Joseph Fourier (Grenoble), 2008. http://tel.archives-ouvertes.fr/tel-00331642.
Der volle Inhalt der QuelleD'abord, les notions nécessaires à la compréhension des techniques considérées sont présentées. Suit la description du développement d'un système IBB-CEAS avec une source LED émettant autour de 643 nm, avec application à la détection des oxydes d'azote à l'état de traces. Les résultats obtenus mettent en avant les avantages de cette technique en termes de simplicité, robustesse et de compacité. La limite de détection obtenue pour le radical NO2 est estimée à 1 ppbv pour deux minutes de temps d'acquisition.
Pour la deuxième étude concernant une source laser de type VECSEL émettant à 2.3 μm et pompé optiquement, le résultat principal a été l'obtention d'un balayage monofréquence sur une grande plage spectrale de l'ordre de 16.5 cm-1. Cela a demandé un balayage simultané de la température et de la longueur de la cavité laser. Ensuite, des essais préliminaires on été effectués pour coupler cette source avec la technique OF-CEAS. Ces essais ont révélé un problème de stabilité du comportement monofréquence de la source VECSEL en présence de rétroaction optique.
Enfin, la faisabilité de la technique OF-CEAS avec une source ECDL émettant dans l'infrarouge proche pour le diagnostic des décharges à basse pression a été démontrée. Le coefficient d'absorption minimale obtenu est de l'ordre de 10-9 cm-1 pour un temps d'acquisition court (0.1 s), valeur typique atteinte auparavant dans divers systèmes OF-CEAS. Des essais ont été réalisés avec une décharge en flux d'argon avec des traces de méthane autour de 1 mbar. Le même niveau de bruit a été observé que sans décharge. Cependant, dans la gamme spectrale accessible avec le ECDL disponible, les radicaux de type CHX produits dans ce type de décharge n'ont pas été détectés.
Hue-Faucheur, Nathalie. „Dissociation en phase gazeuse d'ions organiques complexes par collision de haute énergie et spectrométrie de masse tandem“. Paris 11, 2002. http://www.theses.fr/2002PA112258.
Der volle Inhalt der QuelleThe ionization techniques which proceed from the bombardment of the sample by fast caesium ions (LSIMS) or from the electronebulization of a solution at atmospheric pressure (electrospray, ESI) have been used during this thesis in association with a multi-sectors tandem mass analyzer. From comparison between MS/MS spectra acquired after high energy collisional activation (in the order of kiloelectronvolt) of ionic species arising from one of these ionization methods, it has been shown that the "production mode" of the ions plays a crucial role in dissociation processes via charge-remote fragmentation (CRF). The internal energy of the precursor ions before the collision affects indeed significantly the dissociation behavior after the collisional activation step. Tandem mass spectrometry in combination with high energy collisional activation (CID-MS/MS) and applied to parent ions generated in the LSIMS or ESI ion source allowed the structural elucidation of various natural compounds in complex mixtures and small amounts. It was thus possible to establish unambiguously the double bonds location or branching pattern for aliphatic long chain molecules: serotonin derivatives, acetogenines and glycosphingolipids, with the occurrence of CRF fragment ions that are very specific and highly informative. In addition the structures of cyclic lipopeptides from the surfactine family and oligosaccharides which possess an alditol function and a carboxylic acid group have been characterized
Riviere, Brigitte. „Etude et optimisation d'un plasma induit par microondes, surfatron, en vue d'un couplage avec la chromatographie en phase gazeuse“. Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb376180057.
Der volle Inhalt der QuelleEl, Ouachini Abdelkrim. „Etude de la détection des molécules neutres générées par ablation laser dans différentes conditions de longueur d'onde et d'irradiance“. Metz, 1998. http://www.theses.fr/1998METZ053S.
Der volle Inhalt der QuelleThe purpose of this thesis is to present the conception of experimental devices which allow the direct or non-direct coupling between laser pyrolysis (Py laser) of organic materials and their analyses by Gas Chromatography/Mass Spectrometry (GC/MS). The report describes more precisely the instrumentation and the ablation cells used for the connection between Py laser and GC/MS. Two main laser probe parameters are studied under two complementary axes : the laser wavelength and the power density. The first experimental part consisted in the study of carbon clusters Cn (n < 20) reactivity generated during laser-graphite target interaction. The power density was fixed at 2. 10 9 W. Cm-2 and under liquid or gaseous benzen. The synthetized compounds are solubilized in benzen and concentrated before analysis. This approach is described as an non direct coupling between Py laser and GC/MS. It has been possible to show the influence of the laser experimental parameters (wavelength of the laser, physical state of benzen) on the size and on the composition of the generated clusters. Such way confirms the C2 cluster agregation process. From these results, a new ablation rnicrocell connected directly to the GC/MS has been conceived. By using a such on-line coupling, Py laser-GC/MS of five synthetic polymers were realized under 10 8 W. Cm-2. Such lower power density was necessary to avoid some carbon clusters fragmentation processes which could be a negative effect for samples identification
Lamrini, El-Uahhabi Rachid. „Étude d'un modèle cellulaire et de deux modèles acellulaires de production d'espèces oxygénées réactives : intérêt de la mesure du rapport isotopique 13C-12C par chromatographie en phase gazeuse couplée à la spectrométrie de masse isotopique“. Lyon 1, 1996. http://www.theses.fr/1996LYO1T186.
Der volle Inhalt der QuelleBEAUMIER, GALLON GABRIELLE. „Metabolisme du cholesterol alimentaire. Etudes chez l'homme sain par chromatographie gazeuse-spectrometrie de masse et sur modele enterocytaire humain caco-2“. Aix-Marseille 3, 1999. http://www.theses.fr/1999AIX30017.
Der volle Inhalt der QuelleBen, Abdelouahab Farid. „Etude spectroscopique de différentes phases du système V. . P. O. En relation avec leurs propriétés catalytiques : suivi in situ de catalyseurs par spectrométrie Raman“. Ecully, Ecole centrale de Lyon, 1991. http://www.theses.fr/1991ECDL0021.
Der volle Inhalt der QuelleAubert, Cédric. „Etude de molécules aromatiques scintillantes, application à l'analyse de traces d'actinides par scintillation liquide alpha pour l'environnement“. Paris 11, 2002. http://www.theses.fr/2002PA112195.
Der volle Inhalt der QuelleA new method for actinides measurement by liquid scintillation has been tested for a emitters determination at very low concentration in environmental samples as part of the control of international treaties (Control Test Ban Treaty and Non-Proliferation Treaty). The a liquid scintillation with rejection of b/g emissions is an attractive method because it links a 100 % counting efficiency and a fast sample preparation. Difficulties arise concerning energy resolution (around 250 keV for an α energy of 5 MeV) which hinder the measurement of some actinides like americium. To improve the resolution we have attempted to develop more efficient scintillating cocktails. After photophysics review on fluorescence processes, we have analyzed light emission generated interactions of electrons or α particles in the scintillating mixture. The commercial cocktail Alphaex is chosen as reference to estimate energy resolution and temporal discrimination performances for several mixtures. We have studied several solvents, energy intermediary acceptors and solutes. The cocktail efficiency depends on the energy transfer. We have used the Förster theory and the Millar's equation to characterize energy transfer in homogeneous solution for S1 excited states. An interesting improvement is achieved for PERALS spectrometer with the p-xylene-naphthalene-PBBO cocktail (12 %). The energy resolution for Packard and Wallac spectrometers have been also improved taking into account the physical and chemical behaviors of aromatics molecules
Henry, Franck. „Contribution à l'étude de codépôts de AlN3-Si3N4 par dépôt chimique en phase gazeuse“. Montpellier 2, 1995. http://www.theses.fr/1995MON20024.
Der volle Inhalt der QuelleTin, Philippe. „Métabolites acides de différentes bactéries anaérobies : analyse par chromatographie en phase gazeuse-spectrométrie de masse“. Paris 5, 1991. http://www.theses.fr/1991PA05P175.
Der volle Inhalt der QuelleVan, der Rest Guillaume. „Etude de la reactivite d'ions solvates en phase gazeuse : approche de la solvatation“. Palaiseau, Ecole polytechnique, 1999. http://www.theses.fr/1999EPXX0018.
Der volle Inhalt der QuelleMolinet, Josiane. „Oxydation de la monométhylhydrazine en milieux strictement monophasiques : conception des dispositifs expérimentaux : approche cinétique et mécanistique“. Lyon 1, 1997. http://www.theses.fr/1997LYO10098.
Der volle Inhalt der QuelleLeclerc, Eric. „Réactivité d'ions organophosphorés de basse valence : Approches expérimentale et théorique“. Evry-Val d'Essonne, 2002. http://www.theses.fr/2002EVRY0004.
Der volle Inhalt der QuelleThe objective or this work is the comprehension of the gas-phase reactivity or oxygenated phosphorus cations by using jointly experimental mass spectrometry technique and thoeretical calculations. After a description of experimental and theoretical methods and a bibliographic survey of the phosphonium and phosphenium ions, results relative to the study of a series of ion/molecule reactions are presented. First, we have examined the reactivity of phosphonium ions O=P(0CH3)(index 2)(exponent +) towards olefins, aromatic and polyaromatic hydrocarbons. This study allowed us on the one hand to validate our experimental results using theoretical calculations and on the other hand to propose analytical applications. Then these results led to consider the reactivity of oxygenated phosphorus cations towards different organic functions. We have realized ion/molecule reactions between O=P(OCH3)(index 3)(exponent +) ions and esters and 2,4-diketones. We have shown that adducts lead to ion/neutral complex, of which the decomposition is governed by the proton affinity of neutral counterparts. Finally, we have studied the reactivity of phophenium ions : P(OCH3)(index 2)(exponent +) towards dienic coumpounds. We have studied the reactivity of phosphenium ions : P(OCH3)(index 2)(exponent +) towards dienic coumpounds. We have shown that 1,3-dienes lead to the formation of adduct by [4+2(exponent +)] cycloaddition and that 2,3-diketones react by electrophilic addition
Margarido, Marta. „Etude sur la modélisation mathématique de la cuisson Kraft des espèces pures et mélanges de bois pour la production de pâte à papier“. Grenoble INPG, 2009. http://www.theses.fr/2009INPG0138.
Der volle Inhalt der QuelleThe behaviour during Kraft cooking of a vast series of wood species, including hardwoods and softwoods, have neen studied in a purpose of species comparison and kinetic modelling. The different species were cooked as pure species or mixtures. They were characterized in terms of chemical characteristics (lignin, polysaccharides, hexenuronic acids, pulp yield, molecular composition analysed by Py-GC-MS), and in terms of alkali diffusion properties and morphological evolution during cooking. Macroscopic measurements were completed by microtomographic images on wood chips by X-ray analysis. The results obtained contribute to a general knowledge of Kraft cooking, and also to the development of a mathematical simulator for Kraft cooking modelling
Roucou, Anthony. „Spectroscopie haute résolution de spectres rotationnellement denses dédiée à la détection en phase gazeuse de molécules d'intérêt environnemental et défense“. Thesis, Littoral, 2018. http://www.theses.fr/2018DUNK0482/document.
Der volle Inhalt der QuelleIn recent decades, molecular spectroscopy has benefited from the progress of spectrometers, particularly in terms of selectivity and sensitivity, and from the continuous advancement of the analysis methods and quantum chemistry calculations. Today, rational spectroscopy is moving towards the analysis of more complex molecular systems spectrally characterized by a high density of lines. The spectral congestion of the species studied in this thesis is not only explained by low rotational constants, but also by the presence of vibrational states excited at room temperature, a high isotopic richness, a high degree of line splitting due to large amplitude motions or by a complex conformational landscape. This thesis thus illustrates various scenarios through the studies of thionyl chloride, nitrotoluenes and methoxyphenols. The rovibrational spectra of the v2 and v5 bands of the isotopologues of thionyl chloride were measured in far-infrared at the SOLEIL synchroton and analyzed using a semi-automatic approach based on evolutionary algorithms. The isomers of nitrotoluene have been targeted for military application as explosive taggants (TNT), the pure rotation spectra were measured in the microwave region in molecular jet and in the millimeter-wave region at room temperature. The millimeter-wave spectrum of 3-nitrotoluene was especially weak and congested with very large internal rotation splittings (up to several GHz) due to a very weak rotational barrier (V3=6.7659(24)cmˉ ¹). The detection limit was estimated and a linelist established. The 2-nitrotoluene and 4-nitrotoluene millimeter-wave spectra have been also partially analyzed. Finally, methoxyphenols emitted during biomass fires have also been studied as they are secondary organic aerosol precursors for their future atmospheric detection. Combined with quantum chemistry calculations, the analysis of the millimeter-wave spectrum of the 3-methoxyphenol measured at room temperature permitted the relative stability of four conformers to be determined
Habka, Sana. „Spectroscopie optique des paires d'ions : De la caractérisation des modèles en phase gazeuse à l'identification des paires d'ions en solution“. Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS227/document.
Der volle Inhalt der QuelleIon pairs are ubiquitous in nature andwere documented in sea waters, aerosols andliving organisms, thus they play a crucial role inmany chemical and biochemical mechanisms.Although many experimental approaches aimedat identifying these ion pairs in solutions, theyfailed in characterizing their microscopicproperties, mainly due to the coexistence of manytypes of pairs in solution. This original study aimsto identify the structural properties of ion pairmodels in the gas phase that depicts theinteraction between carboxylate group and alkalication, largely present in biological media.Model systems (M+, C6H5(CH2)nCOO-, M = Li,Na, K, Rb, Cs and n ≤ 4) were the subject of thefirst studies conducted using gas phaseconformational selective IR and UV spectroscopycombined to quantum chemistry calculations.Among the identified structures, we found asecondary interaction between the cation andphenyl ring (cation-π interaction) for systems witha flexible carbon chain, which led us to study thecompetition between cation-anion and cation-πinteractions.The second study developed focused mainly oncharacterizing ion pairs (M+, CH3COO-; M = Li,Na) and free anion in solution, where the firstsolvation layer were described at the quantumlevel, followed by a solvent continuum. Thus thevibrationnal signatures proposed for theseaggregates were compared to solution spectra inlitterature, thus offering a reliable structuralassignement.This study on neutral ion pairs paves way to a betterunderstanding of ion pairing and offers a uniqueapproach to adress the structural characterization ofthese systems in solution
Besacier, Fabrice. „Réalisation d'empreintes isotopiques pour la recherche d'origine des drogues : application à l'héroïne“. Lyon 1, 1999. http://www.theses.fr/1999LYO1T013.
Der volle Inhalt der QuelleLouvet-Helen, Céline. „Développement d'une méthode analytique de dosage des dioxines et composés apparentés par chromatographie en phase gazeuse couplée à la spectrométrie de masse en tandem“. Rennes 1, 2004. http://www.theses.fr/2004REN10123.
Der volle Inhalt der QuelleLe, Caër Sophie. „Etude expérimentale et théorique de la structure et de la réactivité de complexes cationiques du fer en phase gazeuse“. Paris 11, 2003. http://www.theses.fr/2003PA112047.
Der volle Inhalt der QuelleThis thesis aims at characterizing the reactivity of cationic iron complexes with oxygenated molecules in the gas phase, and at comparing the behavior of bidentate ligands (DXE : dimethoxyethane CH3OCH2CH2OCH3) and monodentate ones (water, DME : dimethylether CH3OCH3). Thus, chemical quantum calculations were performed, in combination with Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT -ICR) experiments coupled to bayesian data analysis, and structural characterization by means of Infra-Red MultiPhoton Dissociation (IRMPD) spectroscopy. Primary reactions of Fe(CO)n+ (n = 1-4) with the ligand are substitutions. We have shown that the thermodynamics of these reactions depends on the other ligands. For n = 3-4 the last CO substitution by one water or dimethylether molecule is never observed, in good agreement with electronic structure calculations, suggesting that the last substitution is not thermodynamically favored for n > 2. The calculations suggest that a CO insertion into the C-O bond of dimethylether, leading to an ester CH3COOCH3 ligand is possible when the metallic center is surrounded by at least three ligands. Nevertheless, the infra-red spectrum of Fe+(CO)(CH3OCH3)2 proves that such an insertion did not take place, showing that the associated barriers are too high in energy. We have found that the Fe(DME)+ ion reacts with DME through two competing C-O bond cleavages. The first one is an homolytic cleavage, leading to the formation of Fe(OCH3)(DME)+; whereas the second corresponds to a rearrangement, involving methane loss and leading to the formation of Fe(CH2O)(DME)+. The corresponding branching ratio is very sensitive to the energy of the [Fe(DME)+, DME] system, the loss of methane being favored when its energy is low. In comparison, the behavior of Fe(DXE)+ is very different, since the only ion detected is Fe(CH2O)(DXE)+. We have proven that the insertion of Fe+ in the C-O bond is regioselective, the C atom being a central one