Дисертації з теми "Physique théorique des astroparticules"
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-50 дисертацій для дослідження на тему "Physique théorique des astroparticules".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте дисертації для різних дисциплін та оформлюйте правильно вашу бібліографію.
Dhen, Mikaël. "Muon to electron conversion, flavored leptogenesis and asymmetric dark matter in minimal extensions of the Standard Model." Doctoral thesis, Universite Libre de Bruxelles, 2015. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/217745.
Повний текст джерелаOption Physique du Doctorat en Sciences
info:eu-repo/semantics/nonPublished
Koechler, Jordan. "Phénoménologie de la détection indirecte de matière noire." Electronic Thesis or Diss., Sorbonne université, 2024. http://www.theses.fr/2024SORUS229.
Повний текст джерелаAmong the open problems of modern physics, dark matter (DM) is one of the most fascinating. It explains several gravitational anomalies observed at different scales: the flatness of rotation curves of spiral galaxies, the dynamics of galaxy clusters, the distribution of large-scale structures in the Universe, and the anisotropies in the temperature of the cosmic microwave background. Precise measurements of the latter, possibly combined with other techniques, show that DM constitutes about a quarter of the Universe's energy budget. Although we have reliable observational evidence of DM's existence, its nature remains a mystery, as no observation has yet shown that DM can interact with ordinary matter other than gravitationally. Numerous hypotheses about its nature remain. DM could exist as elementary particles not included in the Standard Model of particle physics, or as macroscopic compact objects such as primordial black holes (PBH). To reveal the nature of DM, or to rule out hypotheses concerning it, several observational techniques are available. In this thesis, we focus on the method of indirect detection, which involves looking for signals of the annihilation or decay of DM in the form of charged cosmic rays, photons or neutrinos. Each product carries different types of information. Photons and neutrinos, being neutral particles, can propagate without being deflected by the surrounding magnetic fields, making it easier to trace their source of emission. Charged cosmic rays, on the other hand, may consist of antimatter, which is less likely produced by astrophysical processes and can therefore be detected with a low background. In this thesis, we study the emission of secondary photons by the interaction of DM products with the galactic environment. Specifically, we consider the case in which DM is a particle with a mass below a GeV. The electrons and positrons produced could interact with ambient photons in the galaxy, producing X-rays through inverse Compton scattering. The prediction of the spectrum of this radiation, compared with data from X-ray observatories, provides strong constraints on this type of DM. Similarly, we apply this same principle to the case of PBH evaporation in order to impose strong constraints on them
Ruamps, Renaud. "Traitement théorique de l'anisotropie magnétique." Phd thesis, Université Paul Sabatier - Toulouse III, 2013. http://tel.archives-ouvertes.fr/tel-01019658.
Повний текст джерелаBardenet, Rémi. "Contributions à l'apprentissage et l'inférence adaptatifs : Applications à l'ajustement d'hyperparamètres et à la physique des astroparticules." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00766107.
Повний текст джерелаNdome, Hameth. "Étude théorique des collisions réactives entre espèces diatomiques." Marne-la-Vallée, 2007. http://www.theses.fr/2007MARN0375.
Повний текст джерелаGoudelis, Andreas. "Detection of WIMP-like dark matter in some extensions of the standard model." Paris 11, 2010. http://www.theses.fr/2010PA112179.
Повний текст джерелаThis thesis treats the detection of dark matter in sorne extensions of the Standard Model of particle physics. Dark matter (DM) is a new matter form whose existence was postulated in order to explain a series of cosmological observations that are in disagreement with current theories in particle physics and cosmology. The tirst chapter of this thesis briefly presents sorne basic elements which are indispensible when working on dark matter. Ln the second chapter, we discuss the potential DM detection modes and we present sorne original results concerning the capacity of the respective experiments to reconstruct some properties of dark matter candidates. Ln the third chapter, we describe a minimal solution to the dark matter problem. The Standard Model of particle physics is slightly extended to accomodate a particle that could constitute the missing mass of the universe and the phenomenology of this particle is studied. Ln the fourth chapter, we present a second solution to the dark matter problem, this time much less minimal or economical. The resulting models (which are called supersymmetric) are considerably more complicated. We study the phenomenology of two such examples. Finally, a summary and sorne conclusions form a fifth chapter. Three appendices follow, containing sorne technical elements as well as a certain number of points aiming at corroborating a few arguments given in the main text
Megi, Fabien. "Étude théorique d'agrégats soumis à des champs laser intenses." Phd thesis, Université Paul Sabatier - Toulouse III, 2005. http://tel.archives-ouvertes.fr/tel-00011994.
Повний текст джерелаPremièrement nous proposons d'ajouter un terme d'amortissement avec la surface au modèle nanoplasma original de T.Ditmire et al. (1996). Nous comparons diverses observables expérimentales (xénon) et étudions l'évolution des états de charge avec la taille ou l'éclairement.
Deuxièmement nous proposons un modèle microscopique de dynamique moléculaire à trois dimensions robuste en l'absence d'excitation. L'émission électronique à 10^11 W/cm^2 (sodium) se compare à celle obtenue par d'autres modèles tels que le modèle VUU-LDA. Les électrons de coeur sont émis à partir de 5 10^15 W/cm^2. Les événements rares sont accessibles et nous montrons que l'explosion ionique de type coulombien est autosimilaire (10^16 W/cm^2). Enfin, l'émission électronique (gaz rare) est comparée avec le modèle nanoplasma.
Ouerfelli, Ghofrane. "Étude théorique de collisions d’intérêt interstellaire." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0224/document.
Повний текст джерелаThe Herschel Space Observatory satellite has permitted to detect light in the far infrared, corresponding to frequencies at which molecules emit light through rotational transitions. ALMA, an interferomete rlocated on the Chilean desert of Acatama took over Herschel and will allow new observations of cold molecular clouds with an accurate angular accuracy. ALMA observes in the range of millimeter andsub-millimeter which makes it complementary to the Satellite Herschel (far infrared). These significant advances in observing particle interactions at the microscopic level, to produce and trap diatomic molecules in specific internal states, open new perspectives in the field of collision physics and theoretical chemistry.Observation of interstellar molecules has benefited from advances in astronomy, to identify vibrational rotational ransitions of molecules. Furthermore, spectroscopic data provide us with important information on the state of the interstellar medium: ionized or neutral.The cation methylidene CH + was observed in the diffuse medium through its X1Σ + -A1Π electronictransition. It plays an important role in the different stages of the complex chemical behaviour through processes and molecular reactions that occur in interstellar and circumstellar regions. So CH+ launches large chain chemical processes that can progress to the formation of more complex species.The fine structure transition of C +; is the strongest emission line of the Milky Way. The C + ion is atracer of density and temperature in diffuse clouds and regions dominated by photons (PDR). The C +line is an important tool to probe the gas content and star formation processes in the Milky Way andother galaxies.C+ + H2 collisions can lead to the formation of CH +. This reaction has been extensively studied theoretically and experimentally, however, it is endothermic by 3211cm-1 and at the typical temperatures for MIS and H2 in its ground vibrational state, the reaction does not occur. The only process is then the C + spin-orbit excitation process.Spin orbit relaxation C + (2P1 / 2) + H 2 (v j) = C + (2P3 / 2) + H 2 (v0; j0) which was first studied inthis thesis contributes to the cooling of the gas constituting the interstellar clouds.The vibrational excitation of H2 (v> 0), which takes place during collisions with C + has a significant influence on the abundance of CH +. CH + is a highly reactive ion, it is destroyed by the abstractionreaction of hydrogen that has been considered in this work. It is therefore interesting to accurately assess the effectiveness of this path of destruction. The dilemma is that this ion is also abundantly found in the neutral and cold environment.This thesis focuses on the inelastic and reactive collisions studies of interstellar interest. We used ab initio highly correlated methods to tackle the electronic structure parts. Moreover, the nuclear dynamics of the systems was studied using a time independent quantum formalism, based on the Jacobi coordinates in the case of the spin-orbit excitation of C + (2P) + ortho H2, and para-H2 and rotational excitation of (+ CD) + He, or the hyper spherical coordinates for the reactive process in the case of the abstraction of a hydrogen in H + CH +.Our concern was to give a comprehensive basis of the mechanisms and provide a quantification of the effective spin-orbit relaxation cross sections and reaction rates to confront with spectroscopic observations. The new rate constants we obtained should help to better interpret the observations of C+ radiation emissions obtained by current and future telescopes
Fathi, Max. "Etude théorique et numérique de quelques modèles stochastiques en physique statistique." Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066349/document.
Повний текст джерелаIn this thesis, we are mainly interested in three topics : functional inequalities and their probabilistic aspects, hydrodynamic limits for interacting continuous spin systems and discretizations of stochastic differential equations. This document, in addition to a general introduction (written in French), contains three parts. The first part deals with functional inequalities, especially logarithmic Sobolev inequalities, for canonical ensembles, and with hydrodynamic limits for continuous spin systems. We prove convergence to the hydrodynamic limit for several variants of the Ginzburg--Landau model endowed with Kawasaki dynamics, with quantitative bounds in the number of spins. We also study convergence of the microscopic entropy to its hydrodynamic counterpart. In the second part, we study links between gradient flows in spaces of probability measures and large deviations for sequences of laws of solutions to stochastic differential equations. We show that the large deviations principle is equivalent to the Gamma--Convergence of a sequence of functionals that appear in the gradient flow formulation of the flow of marginals of the laws of the diffusion processes. As an application of this principle, we obtain large deviations from the hydrodynamic limit for two variants of the Ginzburg-Landau model. The third part deals with the discretization of stochastic differential equations. We prove a transport-Entropy inequality for the law of the explicit Euler scheme. This inequality implies bounds on the confidence intervals for quantities of the form $\mathbb{E}[f(X_T)]$. We also study the discretization error for the evaluation of transport coefficients with the Metropolis-Adjusted Langevin algorithm (which is a combination of the explicit Euler scheme and the Metropolis algorithm)
Palau, Cécile. "Nouveaux radicaux phosphorés pour la polarisation dynamique nucléaire : études théorique et expérimentale." Aix-Marseille 1, 1992. http://www.theses.fr/1992AIX11014.
Повний текст джерелаN'Guiessan, N'Guia Célestin. "Photoréactivité de l'oxyde de benzène, de l'oxépine et de leurs dérivés en matrices cryogéniques : étude par spectrométrie IR-TF." Aix-Marseille 1, 1990. http://www.theses.fr/1990AIX11309.
Повний текст джерелаBendjaballah, Saïda. "Etude théorique de complexes organométalliques du pentalène et d'arènes." Rennes 1, 2004. http://www.theses.fr/2004REN10126.
Повний текст джерелаChepfer, Hélène. "Etude théorique et expérimentale des propriétés optiques et radiatives des cirrus." Lille 1, 1997. http://www.theses.fr/1997LIL10079.
Повний текст джерелаLa comparaison des différentes mesures avec les modeles montre que les données de polarisation (POLDER et lidar) sont très discriminantes pour la microphysique (forme, taille, orientation des cristaux), et que la combinaison de différentes mesures permet de réduire le nombre de modèles susceptibles de les expliquer. Une étude de sensibilité du forçage radiatif met en évidence l'impact important de l'orientation préférentielle des cristaux de glace dans le cirrus
Roussel, Julien. "Analyse théorique et numérique de dynamiques non-réversibles en physique statistique computationnelle." Thesis, Paris Est, 2018. http://www.theses.fr/2018PESC1115/document.
Повний текст джерелаThis thesis deals with four topics related to non-reversible dynamics. Each is the subject of a chapter which can be read independently. The first chapter is a general introduction presenting the problematics and some major results of computational statistical physics. The second chapter concerns the numerical resolution of hypoelliptic partial differential equations, i.e. involving an invertible but non-coercive differential operator. We prove the consistency of the Galerkin method as well as convergence rates for the error. The analysis is also carried out in the case of a saddle-point formulation, which is the most appropriate in the cases of interest to us. We demonstrate that our assumptions are met in a simple case and numerically check our theoretical predictions on this example. In the third chapter we propose a general strategy for constructing control variates for nonequilibrium dynamics. In particular, this method reduces the variance of transport coefficient estimators by ergodic mean. This variance reduction is quantified in a perturbative regime. The control variate is based on the solution of a partial differential equation. In the case of Langevin's equation this equation is hypoelliptic, which motivates the previous chapter. The proposed method is tested numerically on three examples. The fourth chapter is connected to the third since it uses the same idea of a control variate. The aim is to estimate the mobility of a particle in the underdamped regime, where the dynamics are close to being Hamiltonian. This work was done in collaboration with G. Pavliotis during a stay at Imperial College London. The last chapter deals with Piecewise Deterministic Markov Processes, which allow measure sampling in high-dimension. We prove the exponential convergence towards the equilibrium of several dynamics of this type under a general formalism including the Zig-Zag process (ZZP), the Bouncy Particle Sampler (BPS) and the Randomized Hybrid Monte Carlo (RHMC). The dependencies of the bounds on the convergence rate that we demonstrate are explicit with respect to the parameters of the problem. This allows in particular to control the size of the confidence intervals for empirical averages when the size of the underlying phase space is large. This work was done in collaboration with C. Andrieu, A. Durmus and N. Nüsken
Saporta, Albert. "Phenomenological analysis of charged lepton flavour changes." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE1110/document.
Повний текст джерелаIn this doctoral thesis, we investigate charged lepton flavour violating processes in effective field theory, in which possible new physics effects can be parametrized by higher dimensional gauge invariant operators built from Standard Model fields. The discovery of neutrino oscillations is a clear evidence that lepton flavour violation can occur and that neutrinos are massive. In the Standard Model extended with massive neutrinos, charged lepton flavour violating processes are strongly suppressed, and the discovery of such processes would be a clear signal of physics beyond the Standard Model. After a general introduction on the Standard Model of particle physics and beyond, this manuscript contains two introductory chapters. The first one introduce the theoretical and experimental context for the searches of charged lepton flavour violating processes, and their huge potential to constrain new physics model. We make a review of many processes and the current experiments, then we discuss the prospects for the upcoming experiments. The second chapter describe the formalism of the effective field theory approach. We discuss the principles of renormalization and loop integrals calculations with dimensional regularization. We also discuss the renormalization group equations that describe the running and the mixing of the coefficients with the energy scale. Finally, we discuss two different approaches in effective field theories. After introducing the experimental context and the effective field theory formalism, we study the μ → e conversion on nuclei in a top-down approach and charged lepton flavour violating two and three body decays of pseudoscalar mesons in a bottom-up approach. We first list all the operators and their associated coefficients that contribute to the processes. In our work, we mostly focus on dimension six operators. We compute the branching ratios for each processes as a function of the operator coefficients at the experimental scale, and use the experimental upper limit to constrain the coefficients. We also use the renormalization group equations to compute the running and the mixing of the coefficients with energy scale in both top-down and bottom-up approaches. The results discussed in this thesis are based on two publications [1, 2]
Ben-Abdallah, Philippe. "Contribution théorique et numérique à la métrologie thermique inverse." Poitiers, 1997. http://www.theses.fr/1997POIT2340.
Повний текст джерелаLebranchu, Yannick. "Étude d'ondes non linéaires hydrodynamiques : approches théorique et expérimentale." Thesis, Vandoeuvre-les-Nancy, INPL, 2008. http://www.theses.fr/2008INPL005N/document.
Повний текст джерелаA first part is devoted to the study of the Rossby waves that appear in a rotating spherical shell representing the core of a terrestrial planet by thermal instabilities for two heating types. Internal heating is driven by radioactive sources and differential heating is driven by a difference of temperature between the internal and external frontiers. According to the Proudman-Taylor theorem, the flow depends only weakly on the axial coordinate because of the high rotation rate. Thus the 3D models can be simplified into quasi-geostrophic 2D models \textit{via} an axial integration. I present the first systematic comparison between 2D and 3D models (Simitev, U-Glasgow) for weakly nonlinear Rossby waves. In 2D the Landau equation that controls the amplitude of the critical wave is calculated. Predicted convection' amplitude and zonal flows agree rather well with the 3D results. The existence of a subcritical bifurcation is established at very low Ekman numbers with internal and differential heating; in this latter case, the Prandtl number also has to be small for the bifurcation to be subcritical. The second part is an experimental study of water flows and its first instabilities in an annular channel digged in a plate which may rotate, and which is sheared by a rotating lid. Three cases are studied: a pure shear where only the lid turns, a rapid corotation and a pure contrarotation. The onset of instability is studied with global measurements (using a video camera) and local ones (Laser Doppler Anemometry) and is characterized by spiralling waves. In the case of contrarotation, patterns localized in space and time may coexist with the waves. The comparison of these results with numerical ones (Serre, CNRS-Marseille) is done and shows a rather good agreement for the basic azimutal flow and the first instability (critical Reynolds number, wavenumber and angular frequency)
Nguyen, Trung Viet Anh. "Multi renforcement du bois lamellé collé : Etude théorique et expérimentale." Marne-la-vallée, ENPC, 2010. http://www.theses.fr/2010ENPC1012.
Повний текст джерелаBarbe-Le, Borgne Martine. "Étude expérimentale et théorique de la coagulation des aérosols liquides." Paris 12, 1987. http://www.theses.fr/1987PA120021.
Повний текст джерелаHyot, Bérangère. "Etude physique et théorique des matériaux à changement de phase pour disques optiques." Grenoble INPG, 2001. http://www.theses.fr/2001INPG0087.
Повний текст джерелаLe, Grognec Erwan. "Développements de complexes organométalliques de Mo(III) et leur utilisation en polymérisation." Dijon, 2000. http://www.theses.fr/2000DIJOS062.
Повний текст джерелаHernandez, Garduza Otilio. "Etude des modèles thermodynamiques susceptibles de représenter les mélanges contenant essentiellement des hydrocarbures, de l'eau et des alcools." Aix-Marseille 1, 1993. http://www.theses.fr/1993AIX11003.
Повний текст джерелаBercegeay, Carole. "Étude théorique des alliages binaires tantale-tungstène." Université de Marne-la-Vallée, 2006. http://www.theses.fr/2006MARN0280.
Повний текст джерелаThe aim was to calculate melting temperatures of Ta-W binary alloys. Firstly we calculated equilibrium properties (equations of state, elastic constants, formation energies) at 0 K for pure metals and Ta1-xWx intermetallic compounds, in the framework of DFT by using pseudopotentials. These ab initio data were used to fit a MEAM-2NN potential to represent the interactions between tantalum and tungsten atoms in Ta-W alloys. The obtained cross-potential was then used in molecular dynamics simulations to calculate the melting temperatures of Ta-W alloys. The melting temperature predicted for tantalum by the fitted potential agree with the experimental value. But for tungsten the results disagree strongly with the experiment: the predicted melting temperature is over estimated by 1000 K. It induces an error in the prediction of melting temperatures for Ta-W alloys. Our attempts to improve the MEAM potential for tungsten have only permitted to reduce the difference by 200 K
Guthmuller, Julien. "Étude théorique de molécules conjuguées d’intérêt biologique pour l’optique non linéaire." Lyon 1, 2006. http://www.theses.fr/2006LYO10183.
Повний текст джерелаThis thesis presents a density functional theory (DFT and TDDFT) study, in which we describe the non linear optical response of molecular probes in biological environment. The considered systems are first push-pull molecules (nitrobenzene substituted by an electronic donor group) in connection with the para-nitrophenylphosphate molecule and secondly the aromatic amino acids, tryptophan, tyrosine and phenylalanine. In this work, we determine the ground state and excited states electronic structure, as well as the components of the polarizability and hyperpolarizability tensors, describing the optical properties of the molecule. The description of the biological environment, particularly the aqueous solvent surrounding the molecules, is realized by means of a polarisable dielectric model and by solvent molecules forming hydrogen bounds with the solute
Zaghzi, Nacira. "Etude théorique et expérimentale de l'adhésion instantanée élastomère-métal à l'aide d'une méthode de roulement." Mulhouse, 1986. http://www.theses.fr/1986MULH0017.
Повний текст джерелаRobbins, Glenn. "New Physics at Colliders and in Space." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1149/document.
Повний текст джерелаThe quest for new physics is a challenging task which involves, on the one hand, the search for dark matter particles from space, and on the other hand, the search at colliders for particles predicted by theories beyond the Standard Model, such as supersymmetry. With the experimental constraints on new particles getting stronger, it becomes crucial to combine the limits from both sectors in order to guide future searches. To this end, it is essential to estimate and take into account correctly the astrophysical, nuclear and cosmological uncertainties, which are most often ignored. The first part of this thesis is dedicated to the study of such uncertainties and to their impact on the constraints applied on supersymmetry. Moreover, we investigate the interplay between the constraints from colliders and dark matter searches in some detail. The second part concerns the development and the implementation in the public code SuperIso Relic of numerical tools for the calculation of direct and indirect dark matter detection constraints which were designed specifically to take correctly into account astrophysical and nuclear uncertainties. Finally, in the third part of this work, we consider the cosmological implications of a hypothetical discovery of new particles at colliders. We show that it would be possible to test the assumptions of the standard cosmological model and to obtain information on the properties of the primordial Universe at an epoch which is beyond observational reach
Ngome, Abiaga Juste Jean-Paul. "(Super) symétries des modèles semi-classiques en physique théorique et de la matière condensée." Phd thesis, Tours, 2011. http://tel.archives-ouvertes.fr/tel-00622874.
Повний текст джерелаCastanié, Fabien. "APPROCHES NUMÉRIQUE ET THÉORIQUE DU MICROSCOPE À FORCE ATOMIQUE : INTERACTION, DYNAMIQUE ET IMAGERIE." Phd thesis, Université Paul Sabatier - Toulouse III, 2012. http://tel.archives-ouvertes.fr/tel-00788143.
Повний текст джерелаPaul, Séverine. "Modèle de Hartree-Fock-Bogoliubov : une perspective théorique et numérique." Phd thesis, Université de Cergy Pontoise, 2012. http://tel.archives-ouvertes.fr/tel-00752813.
Повний текст джерелаElzo, Dominique. "Étude théorique et expérimentale de l'adhésion de particules de taille micronique sur une surface plane." Toulouse, INPT, 1994. http://www.theses.fr/1994INPT097H.
Повний текст джерелаZapata-Massot, Céline. "Synthèse de matériaux composites par co-broyage en voie sèche. Caractérisation des propriétés physico-chimiques et d'usages des matériaux." Phd thesis, Toulouse, INPT, 2004. http://oatao.univ-toulouse.fr/7699/1/zapata_massot.pdf.
Повний текст джерелаFromm, Michel. "Evaluation des potentialités d'un polymère isotrope (CR 39) en tant que détecteur de traces nucléaires pour la dosimétrie neutron et la microcartographie alpha." Besançon, 1990. http://www.theses.fr/1990BESAA006.
Повний текст джерелаZajicek, Tomas. "Adaptation de la spectrométrie d'absorption infrarouge à l'analyse des modifications physicochimiques superficielles de films de polyéthylène téréphtalate sous frottement." Besançon, 1987. http://www.theses.fr/1987BESA2026.
Повний текст джерелаNguyen, Duc Hanh. "Mise en évidence de la voie palladium-hydrure dans les réactions d'alcoxycarbonylation et cyclocarbonylation de monoterpènes : extension aux aminesallyliques." Toulouse, INPT, 2004. https://hal.science/tel-04608129.
Повний текст джерелаThis study is focused on the mechanism by which a monoterpene suffers a cyclocarbonylation reaction catalysed by a palladium complex. Evidences are provided, based on intermediate species observed under pressure or with stabilizing ligands, that the catalytic cycle follows a hybride route starting from [Hpd(SnCl3)L2]. Cationic complexes of type [Pd(H)(L2)(L')]+ or palladium (0) precursors show either an absence or a reduced reactivity. Moving to the model platinum complex chemistry, an acyl species has been intercepted. Most of the observations are done on the cyclocarbonylation of isopulegol, dihydromyrcenol, isolimonene into the corresponding lactones or cyclopentanones. Dihydromyrcene led us to observe the platinum-acyl complex and the corresponding elusive palladium-acyl species. The co-catalytic role of SnCl2 is also demonstrated
Menais, Timothée. "Etude théorique de la translocation de biomolécules à travers une membrane fine." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAY003/document.
Повний текст джерелаSo as to facilitate genomic sequencing, a third generation of sequencing devices is needed. Biopolymer translocation is the key phenomenon involved in nanopore sequencing prospects. We investigated this phenomenon through both theoretical and numerical approaches. Our work started with devicing a coarse grained structured polymer (with a DNA like structure) adapted to a molecular dynamics study. Once we have verified the reliability of our model towards statistical polymer physics, we focused on translocation. We reinvestigated the common case of a nanopore within a fix membrane and proposed a theoretical model for translocation under a pulling force. The arrival of thin membranes is key to an eventual success of non destructive sequencing with a nanopore. This enables new interactions with the membrane which have not been investigated yet. We provide the first large scale numerical investigation of such interactions. our results provide an insight over the influence of membrane vibrations, deformability and flexibility
Terrier, Hugo. "Étude théorique des collisions ultra-froides en réseau optique." Thesis, Rennes 1, 2016. http://www.theses.fr/2016REN1S028/document.
Повний текст джерелаAn optical lattice, created by lasers, can trap atoms cooled to ultra-low temperatures. It provides a constraint as if it were a perfect crystal (a crystal without thermal agitation). I describe the states of particles in a periodic potential (optical network) using probability waves (quantum physics) stationary (independent theory of time). The wave nature of the material is exacerbated at very low temperatures and gives rise to interference phenomena and individual resonance
Constantin, Georges. "Etude théorique de l'excimère ionique Xe+Rb excité par faisceau d'électrons relativistes." Aix-Marseille 1, 1996. http://www.theses.fr/1996AIX11007.
Повний текст джерелаGomri, Sami. "Spectroscopie du bruit électronique dans les microcapteurs de gaz : étude théorique et expérimentale." Aix-Marseille 1, 2006. http://www.theses.fr/2006AIX11047.
Повний текст джерелаWolff, Jean. "Un modèle théorique des mélanges ternaires de lipides et de cholestérol." Phd thesis, Université de Strasbourg, 2013. http://tel.archives-ouvertes.fr/tel-01068363.
Повний текст джерелаBerthoz, Nicolas. "Modélisation physique et théorique du creusement pressurisé des tunnels en terrains meubles homogènes et stratifiés." Phd thesis, INSA de Lyon, 2013. http://tel.archives-ouvertes.fr/tel-00786231.
Повний текст джерелаGharnati, Ahmed. "Contribution de la simulation numérique sur ordinateur à la résolution des problèmes en physique théorique." Nancy 1, 1991. http://www.theses.fr/1991NAN10064.
Повний текст джерелаPinat, Elisa. "The IceCube Neutrino Observatory: search for extended sources of neutrinos and preliminary study of a communication protocol for its future upgrade." Doctoral thesis, Universite Libre de Bruxelles, 2017. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/253046.
Повний текст джерелаFrench Version: Quand les humains ont commencé à regarder le ciel étoilé, l’astronomie est née. Les photons émis par les étoiles voyagent parfois des milliards d’années lumière avant d’atteindre nos yeux, et c’est grâce à l’étude de ce flux de photons que l’on peut déduire les propriétés des étoiles mêmes. Au lieu des photons, l’Observatoire IceCube, situé au Pôle Sud, a pour but de détecter des neutrinos :il espère éclairer le mystère encore non résolu de l’accéleration et des mécanismes de production des rayons cosmiques, ainsi que des phénomènes les plus énergétiques de l’Univers. Au moment où ce document a été rédigé, IceCube a démontré l’existence d’un flux de neutrinos astrophysiques avec une signification statistique excédant sept sigmas. Cependant, le flux de neutrinos astrophysiques observé ne montre aucun regroupement directionnel significatif ni une évidence d’association avec aucune source connue à l’heure actuelle. De plus, les derniers résultats fournis par les analyses de sources ponctuelles de la collaboration IceCube ne montrent non plus aucun regroupement. Il est donc important d’étendre ces recherches vers des typologies de sources différentes pour maximiser le potentiel de son découverte. Dans la première partie de ce travail nous présentons une analyse de source étendue basée sur sept années de données d’IceCube, ce qui rajoute trois ans de données au travail précédemment publié tout en mettant en oeuvre une nouvelle formulation de maximum de vraisem- blance. Comme les extensions de sources potentielles ne sont pas connues à priori, cinq extensions différentes ont été considérées, de 1° à 5°. Aucun regroupement significatif n’a été observé sur aucune des cartes. La capacité d’IceCube de consolider l’astronomie neutrino en découvrant des sources de neutrinos est limitée par le nombre de neutrinos cosmiques mesuré. Malgré la découverte susmentionnée d’un flux astrophysique, les études détaillées de spectre ainsi que les recherches de sources spécifiques pour ce type de signal demeurent un défi, à cause de la limitation de taille disponible des échantillons avec l’instrument IceCube. Par conséquent, une expansion considérable du détecteur actuel, IceCube Gen2, est promue :elle inclut l’instrumentation d’un volume de 10 km3, apte à fournir une augmentation importante des échantillons de neutrinos de toutes les saveurs. Non seulement le hardware sera mis à niveau, mais de nombreux autres systèmes subiront des améliorations, comme les infrastructures de communication et de timing. Un nouveau système de communication a été étudié et est présenté dans la deuxième partie de ce document. Le Binary Phase Shift Keying (BPSK), la technique de modulation numérique la plus simple, a été étudiée comme technique potentielle pour IceCube Gen2.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
Haro, Poniatowski Emmanuel. "Étude expérimentale et théorique de l'anharmonicité dans le silicium." Paris 6, 1986. http://www.theses.fr/1986PA066066.
Повний текст джерелаBonfanti, Silvia. "Etude théorique et numérique des verres structuraux à basse température." Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTT281.
Повний текст джерелаAt low temperature, i.e. in the 1K regime, glasses show properties that are remarkably different from those of the corresponding crystalline counterparts, e.g., the heat capacity depends approximately linearly and the thermal conductivity almost quadratically on temperature (in crystals one finds a cubic dependence for both properties).Many of these observations can be rationalized by the so-called “Standard Tunneling Model” (STM) whose basic assumption is the existence of local double-well potentials, or two level systems, in the potential energy landscape, where localized excitations (a particle or rather a cluster of particles) undergo quantum tunneling through the barrier. In recent times the tunneling systems (TSs) have attracted considerable attention for the fabrication of coherent qubits for quantum computers involving amorphous superconducting Josephson junctions.However, despite the success of the STM, many features of the model are still unclear in that, e.g., the microscopic nature of the TSs remains unknown. In addition, unexpected magnetic effects have been discovered in non-magnetic multi-component glasses, like e.g. the non-monotonous changes of the dielectric constant and the specific heat in the presence of weak magnetic fields.A possible explanation of these observations is the so-called “Extended Tunneling Model” (ETM) in which one assumes the presence of better ordered regions, hosting TSs in the interstices, that have to be described by three-well potentials (TWPs), in the intermediate range structure of glasses; as a result the effective tunneling particles can couple to the magnetic field via the Aharonov-Bohm effect.This work consists of two parts: In the first one we carry out analytical calculations to generalize the ETM model to the case of a four-well tetrahedral trapping potential in a magnetic field. Our calculations show that in fact the TWP can be considered as the simplest working model to describe real glasses. We also derive the contribution to the magnetization from the TWPs of our model, and obtain fits that are in good agreement with the experimental data. We show that only taking into account such tunneling geometry we get a good agreement between the impurity concentrations extracted from the magnetization and those extracted from low-temperature heat capacity measurements. This is thus evidence for the presence of structural inhomogeneities in glasses at low temperature.The goal of the second part is to elucidate the nature of the TSs via computer simulations. For this we first develop new algorithms to study the geometry of the minima and barriers of a simple two-dimensional model of a potential energy surface. This study is the starting point for a novel method, the so-called “Effective Isopotential Method”, that we introduce to perform a local and systematic analysis of the energy landscape close to the bottom of the local minimum.We apply this method to a test case, a Lennard-Jones FCC crystal, and then to a binary mixture Lennard-Jones glass at low temperature. We find that the geometric shape of the IS at low temperature is not smooth but is characterized by internal valleys, i.e. points of the configuration space where the potential energy is lower than the immediate neighborhood. In the case of the crystal we observe the presence of six symmetric valleys associated with a given particle, while in the glass case we find that most of the particles show only two valleys. Amongst them we find the geometries with the right semi-quantitative features (in agreement with the phenomenological models) to be considered as TSs, so that we finally know how they look like in reality
Pfister, Olivier. "Etude expérimentale et théorique des interactions hyperfines dans la bande de vibration v3 de la molécule 28SiF4." Paris 13, 1993. http://www.theses.fr/1993PA132022.
Повний текст джерелаMaurat, Emmanuel. "Étude théorique de la dynamique de charge et de spin de structures électroniques confinées." Strasbourg, 2009. https://publication-theses.unistra.fr/public/theses_doctorat/2009/MAURAT_Emmanuel_2009.pdf.
Повний текст джерелаIn this first approach, the dynamic aspects are modeled using concepts of statistical mechanics at the thermodynamic equilibrium. By using the Local Spin Density Functional Theory (LSDA-DFT) at finite temperature and within the grand canonical ensemble, we have studied the magnetic properties of small metal particles with open-shell structures made up of elements which are no magnetic in the bulk (like the noble metals Ag, Au or Pt). As for ferromagnetic bulk materials, these nano objects present a ferromagnetic-paramagnetic second order phase transition at a critical temperature which depends heavily on their size and on the electronic correlations. We have shown that the magnetic susceptibility obeys the Curie-Weiss law. This result is due to the finite size of the system implying a discrete spectrum of electronic levels and is consistent with recent measurements on aggregates of platinum sorted by mass [109]. Thus, when the electron temperature increases sharply, the magnetization decreases. Then, through the electron-phonon coupling the thermal energy is distributed over the lattice, which in turn decreases the electron temperature and allows the resurgence of the magnetization. This analysis is supported by some experimental results as the fact that the demagnetization is more or less pronounced according to the Curie temperature of the material [130]. Thanks to the linear response theory for LSDA-DFT that we developed, we were also able to find the features of a such demagetization on optical spectrums. However, this model is only qualitative. Indeed, the mechanisms that are causing the phenomenon of demagnetization are hidden by the statistical treatment of the problem. The spin magnetic moment (which, for metals, is essential to the magnetization of the system) may be redistributed on the orbital moment via spin-orbit coupling. The latter is of relativistic origin and must be added to the non-relativistic Hamiltonian describing the usual light-matter interaction. A few years ago, this hypothesis had already been discussed by G. P. Zhang and W. Hübner [149] to explain the demagnetization in ferromagnetic films. However, it was later refuted by B. Koopmans [131] ; the parameters used in [149] are not compatible with those used in experiments. First, in order to make us our own ideas on the subject and second, to extend to finite systems the studies conducted for the bulk, we have investigated the effect of spin-orbit coupling on the spin dynamics in nanoparticles. To this end, still using the jellium model (assuming a purely electronic processus), we choosed the TDDFT approach (Time Dependent Density Functionnal Theory) which have been completed by the introduction of the spin-orbit coupling term. We have thus observed that the spin-orbit coupling is a good mechanism for demagnetization, but it is not sufficient to explain the experimental observations. Indeed, as confirmed by a recent publication [? ], the quantity of orbital angular momentum is not a good reservoir to absorb the amount of spin angular momentum coming from the demagnetization. However, if the mechanism induced by the spin-orbit coupling is not sufficient to explain the full demagnetization, it is necessary as explained in the last part. In addition, we were able to highlight the important role played by the polarization of the laser pulse in the demagnetization process. This last aspect has been recently confirmed experimentally [138]. In the very last part of the manuscript, we propose a microscopic mechanism allowing to go beyond mean field which involves jointly the electron-electron collisions, the spin-orbit coupling and the conservation of total angular momentum. A diagram of the algorithmic model is proposed to allow its implementation in a standard TDDFT approach. Indeed, we believe that a redistribution of angular momentum induced by electron collisions must play a crucial role in the demagnetization phenomenon and all the more so that (i) the electronic temperatures, because of the interaction with the laser, are very high, and (ii) the highly nonlinear processes of electron collisions
Lahmidi, Noureddine. "Etude théorique des effets de corrélation électronique dans l'ionisation dissociative de H2 et l'ionisation double de Li par impact d'électron rapides." Metz, 2006. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/2006/Lahmidi.Noureddine.SMZ0616.pdf.
Повний текст джерелаRecent progress made in the coincidence detection of emerging particules from an inelastic collision has risen new interest for fundamental studies in the field of dissociative ionization of diatomic molecules by electron impact. The detection in coincidence of the ejected and the scattered electrons give information about the electronic structure and the mechanisms of the simultaneous processes of ionization and dissociation. Moreover, the detection of one of the two emerging protons enables us to obtain the variation of the multiplement differential cross section for a given orientation of the internuclear axis ofthe target. The study of the double excitation of an atomic or molecular system is one of the basic problems of atomic physics, where the electronelectron correlation can be experimentally observed Our aim is to study theoretically two particular processes of this type. 1)- The dissociative ionization of H2 and Li2 as a vertical transition from the fundamental electronic) l state of H2 and Li2 to the first dissociative 'Ij ttut. Of H2* and Li2*. 2)- The double Ionization of the K-shell of atomic lithium by using the correlated wave functions for the description of the double electronic continuum
Videcoq, Arnaud. "Auto-organisation de surfaces cristallines pendant la croissance épitaxiale : une étude théorique." Clermont-Ferrand 2, 2002. http://www.theses.fr/2002CLF21383.
Повний текст джерелаMartinez, Hervé. "Processus d'intercalation dans le disulfure de titane, études expérimentale (microscopies à champ proche et spectroscopie photoélectronique à rayonnement X) et théorique." Pau, 1996. http://www.theses.fr/1996PAUU3020.
Повний текст джерелаLetois, Bertrand. "Synthèse et étude physicochimique de nouveaux 5,11-diméthyl-6H-pyrido[3,2-b] carbazoles à visée antitumorale." Caen, 1991. http://www.theses.fr/1991CAEN4038.
Повний текст джерела