Dissertationen zum Thema „Mathématiques condensées“
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Daurel, Thomas. „Représentations condensées d'ensembles de règles d'association“. Lyon, INSA, 2003. http://www.theses.fr/2003ISAL0059.
Der volle Inhalt der QuelleRecently, the more and more intense usage of information systems yielded to the growth of the number and the size of the involved databases. The owners felt more and more the potential value of those databases. They started trying to these databases to advantage without being restricted to classical querying processes, but by attempting to extract information enclosing high added value, which could lead to the improvement of the users’ knowledge. This issue led to the creation of a new discipline : frequent pattern extraction. A lot more and more efficient algorithms were developed to address this kind of extraction since 1994. It is now often possible to extract in an exhaustive way in most of the cases certain types of frequent patterns enclosed in a database. The major drawback that met is the following : the discovered patterns are often too numerous. It is therefor difficult to sort them following an interest order in order to derive interesting information. In this context, it appeared that it is particularly interesting to find out more condensed representations of the extracted patterns in order to ensure a better reading of the results. More precisely, we have worked on the patterns called association rules, and we have proposed two global representations of association rules sets. We have designed and implemented tow algorithms for calculating each one of these representations, and we have shown their efficiency and effectiveness in practice. At last, we have conducted tests on real-life datasets
Artusa, Marco. „Sur des théorèmes de dualité pour la cohomologie condensée du groupe de Weil d'un corps p-adique“. Electronic Thesis or Diss., Bordeaux, 2024. http://www.theses.fr/2024BORD0228.
Der volle Inhalt der QuelleThe goal of this thesis is twofold. First, we build a topological cohomology theory for the Weil group of p-adic fields. Secondly, we use this theory to prove duality theorems for such fields, which manifest as Pontryagin duality between locally compact abelian groups. These results improve existing duality theorems and give them a topological flavour. Condensed Mathematics allow us to reach these objectives, providing a framework where it is possible to do algebra with topological objects. We define and study a cohomology theory for condensed groups and pro-condensed groups, and we apply it to the Weil group of a p-adic field, considered as a pro-condensed group. The resulting cohomology groups are proved to be locally compact abelian groups of finite ranks in some special cases. This allows us to enlarge the local Tate duality to a more general category of non-necessarily discrete coefficients, where it takes the form of a Pontryagin duality between locally compact abelian groups. In the last part of the thesis, we use the same framework to recover a Weil-version of the Tate duality with coefficients in abelian varieties and more generally in 1-motives, expressing those dualities as perfect pairings between condensed abelian groups. To do this, we associate to every algebraic group, resp. 1-motive, a condensed abelian group, resp. a complex of condensed abelian groups, with an action of the (pro-condensed) Weil group. We call this association the condensed Weil-´etale realisation. We show the existence of a condensed Poincar´e pairing for abelian varieties and we prove a condensed-Weil version of the Tate duality with coefficients in abelian varieties, which improves the correspondent result of Karpuk. Lastly, we exhibit a condensed Poincar´e pairing for 1-motives. We show that this pairing is compatible with the weight filtration and we prove a duality theorem with coefficients in 1-motives, which improves a result of Harari-Szamuely
Chiron, David. „Etude mathématique de modèles issus de la physique de la matière condensée“. Paris 6, 2004. http://www.theses.fr/2004PA066053.
Der volle Inhalt der QuelleRoyo-Letelier, Jimena. „Etude de modèles mathématiques des condensats de Bose-Einstein pour différents types de pièges et d'interactions“. Versailles-St Quentin en Yvelines, 2013. http://www.theses.fr/2013VERS0028.
Der volle Inhalt der QuelleThis PhD thesis is devoted to the mathematical study of theoretical models for Bose-Einstein condensates. We consider the Gross-Pitaevskii functional for several types of trapping potentials and interactions. We analyze models for two-dimensional condensates defined over all R2, under rotation and with several components. We also analyze a model for a charged particle in a two-dimensional periodic media under magnetic field. The mathematical tools employed are partial differential equations, nonlinear analysis, geometric measure theory, spectral theory and semi-classical analysis. They are four main results. The first one establishes the non existence of vortex in the low density zone of a condensate under subcritical rotation. The second result proves the segregation and the symmetry breaking of a two components condensate in the strongly coupled and weakly interacting regime. We also solve an optimal partition problem associated with a Schrödinger operator in R2. We introduce a new minimal perimeter model for the study of two components condensate in the strongly coupled and strongly interacting regime. The third result is about the I-convergence of the energy functional of a two-component condensate in this last regime. The last result concerns the spectrum of a magnetic periodical Schrödinger operator on the kagome lattice
Bourdin, Félicien. „Modélisation macroscopique de mouvements de foule à deux types, modèles SIR condensés“. Thesis, université Paris-Saclay, 2022. http://www.theses.fr/2022UPASM013.
Der volle Inhalt der QuelleWe study in this thesis the macroscopic modelling of crowd motion in the case of a population divided in several types that may have different behaviours, as well as the development of SIR models in order to analyse the spread of an infectious disease in a school. These two issues were studied separetely. As the original topic of this thesis was crowd motion, we answered to a proposition of MODCOV19 - a platform created by CNRS and INSMI to centralize and coordinate modeling projects on the COVID-19 outbreak - to design epidemiological models adapted to school media. This work is thus composed of two independent parts. On the one hand we analyse the convergence of several numerical schemes that stem from different standpoints on the macroscopic crowd motion equation - optimal transport, gradient flow, finite volumes. We study as well the homogenization of microscopic models of particles towards the macroscopic model. We eventually investigate the inverse problem of identifying of the parameters of a model, being observed the motion of a crowd. On the other hand, we develop a class of ``condensed'' SIR models, where the epidemiological quantities are defined at the scale of groups of individuals. We formally analyse the quality of the condensation process when a full description of the interaction within the population is available. We then detail the implementation carried out in collaboration with MODCOV19
Cotfas, Nicolae. „Modèles mathématiques pour cristaux et quasicristauxX“. Grenoble INPG, 1998. http://www.theses.fr/1998INPG0130.
Der volle Inhalt der QuelleHoonakker, Frank. „Graphes condensés de réactions, applications à la recherche par similarité, la classification et la modélisation“. Université Louis Pasteur (Strasbourg) (1971-2008), 2008. https://publication-theses.unistra.fr/restreint/theses_doctorat/2008/HOONAKKER_Frank_2008.pdf.
Der volle Inhalt der QuelleThis work is devoted to the developpement of new methods of mining of chemical reactions based on the Condensed Graph of Reaction (CGR) approach. A CGR integrates an information about all reactants and products of a given chemical reaction into one 2D molecular graph. Due to the application of both conventional (simple, double, etc. ) and dynamical (single to double, broken single, etc. ) bond types, a CGR ”condenses” a reaction (involving many molecules) into one pseudo-molecule. This formally allows one to apply to CGRs the chemoinformatics approaches earlier developed for individual compounds. Three possible applications of CGRs were considered: – unsupervised classification of reactions based on clustering algorithms; – reactions similarity search, and – Quantitative Structure Reactivity Relationships (QSRR). Model calculations performed on four databases containing from 1 000 to 200 000 reactions demonstrated high efficiency of the developed approaches and software tools. An system for optimizing reactions condition has been designed, and patented in the USA
Florens, Serge. „Coherence et localisation dans les systemes d'electrons fortement correles“. Phd thesis, Université Pierre et Marie Curie - Paris VI, 2003. http://tel.archives-ouvertes.fr/tel-00005825.
Der volle Inhalt der QuelleHerzog, Basile. „Chemically accurate simulations by machine learning correlated approximations“. Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0126.
Der volle Inhalt der QuelleThe ability to systematically compute physical properties at chemical accuracy would be of tremendous help for efficient in silico material discovery, drug design or chemical reaction pathways study. While density functional theory has become the workhorse of materials simulations, the quality of results unfortunately often varies depending on the specific choice of the exchange-correlation functional, andthis significantly limits the predictive power of this approach. More correlated approaches, such a coupled cluster theory, the random phase approximation, or configuration interaction, provide more reliable results in a systematically improvable way. Their computational cost however render them inaccessible in a lot of applications, and this is particularly true for finite temperature properties, where many samples calculations are necessary to reproduce ensemble averages. Machine learning (ML) on the other, has proven its ability to efficiently reduce computational costs by using knowledge from previous calculations. The aim of this thesis is to contribute to the on-going development of ML assisted methods to obtain chemically accurate calculations. Machine learning perturbation theory (MLPT) is a recent promising approach capable of obtaining chemically accurate finite temperature properties by producing ensemble property estimates for highly expensive computational methods. This is achieved by learning the energy difference between two methods, using few samples from a reference statistics produced from a computationally feasible level of theory, and reweighting the later statistics to the computationally inaccessible target method, with thermodynamic perturbation theory (TPT). In this thesis, the MLPT method is tested against possible limitations of TPT, when a poor overlap between reference and target configurational space produce biased target estimates. A diagnostic test for this problem is proposed, together with a solution in the form of Monte Carlo resampling using the same ML model. MLPT is further applied to compute a coupled cluster estimate of the adsorption enthalpy of carbon dioxide inside a periodic zeolite. Finally, on another topic, a new method is presented, in the framework of configuration interaction (CI), to efficiently iteratively sample new Slater determinants using a generative ML model. This algorithm, called CIgen, is shown to be competitive or outperform other Monte Carlo and ML approaches to the CI problem
Théveniaut, Hugo. „Méthodes d'apprentissage automatique et phases quantiques de la matière“. Thesis, Toulouse 3, 2020. http://www.theses.fr/2020TOU30228.
Der volle Inhalt der QuelleMy PhD thesis presents three applications of machine learning to condensed matter theory. Firstly, I will explain how the problem of detecting phase transitions can be rephrased as an image classification task, paving the way to the automatic mapping of phase diagrams. I tested the reliability of this approach and showed its limits for models exhibiting a many-body localized phase in 1 and 2 dimensions. Secondly, I will introduce a variational representation of quantum many-body ground-states in the form of neural-networks and show our results on a constrained model of hardcore bosons in 2d using variational and projection methods. In particular, we confirmed the phase diagram obtained independently earlier and extends its validity to larger system sizes. Moreover we also established the ability of neural-network quantum states to approximate accurately solid and liquid bosonic phases of matter. Finally, I will present a new approach to quantum error correction based on the same techniques used to conceive the best Go game engine. We showed that efficient correction strategies can be uncovered with evolutionary optimization algorithms, competitive with gradient-based optimization techniques. In particular, we found that shallow neural-networks are competitive with deep neural-networks
Suarez, Jimmy. „Modélisation de la combustion diphasique de l’aluminium et application sur la post-combustion d'une charge explosive condensée dans l'air“. Thesis, Toulouse, INPT, 2020. http://www.theses.fr/2020INPT0099.
Der volle Inhalt der QuelleThe combustion of aluminum is a phenomenon present in many fields, such as the space, defense and automotive fields. Once ignited, an aluminum particle represents an excellent energy carrier for the surrounding flow with its high energy density. Its combustion with air, or with other oxidants, has been the subject of some experimental and numerical studies, which has highlighted one of the particularities of this two-phase combustion. During the aluminum combustion, it produces a species called alumina which exists only in the liquid phase in its burning gases. This particularity makes the modeling of the two-phase combustion of aluminum complex to model. The objective of this thesis is divided into two parts. The first part is to develop a model of two-phase combustion of aluminum with air. This modeling is an Euler-Lagrange simulation created with AVBP, which is a simulation code implemented by CERFACS. It takes into account the rapid combustion of aluminum in the gaseous phase and the phase changes that occur such as the melting and evaporation of aluminum, but also the condensation and solidification of alumina. A germination method is developed to allow the condensation of alumina in the burning gases and to follow its growth in a Lagrangian way behind the aluminum-air flame. This modeling allowed us to simulate 1D and 2D aluminum-air flames to compare them to the experimental data found in the literature. The second part of this thesis is the analysis of the dispersion and the energetic participation of aluminum in the post-combustion of an explosive charge. The phenomenon of post-combustion is very bright and rapid, which experimentally prevents knowing the evolution of the state of the aluminum particles initially contained in the explosive charge. These simulations make it possible to follow the dispersion of the particles and their interactions with the different phases that make up the post-combustion. An isolated particle combustion model is taken from the literature and adapted to our case study. Thus the influence of the physical presence of particles and of the heat released by their combustion could be evaluated on the evolution of the fireball and the propagation of the secondary shock. All of this thesis work, whether for the modeling of the aluminum-air flame and the analysis of the impact of aluminum on the post-combustion, showed convincing results compared to the data of the literature. The numerical models used and developed are promising for future studies on the combustion of aluminum
Di, Marco Angelo. „Phénomènes électriques et thermiques dans des nanostructures supraconductrices“. Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAY099/document.
Der volle Inhalt der QuelleThe aim of my Ph.D. thesis is to study theoretically the thermoelectric phenomena occurring in some superconducting nanostructures which are the object of various research lines in condensed matter physics. Specifically, we focus on four different devices based on superconductors and insulating tunnel barriers where both charge and heat transport are governed by the quantum tunneling effect. We start by considering a voltage-biased Normal metal-Insulator-Superconductor (N-I-S) tunnel junction. No single-particle current is expected to flow in this circuit when the applied voltage is below the superconducting energy gap of S. However, in real experiments, a subgap leakage current is observed in the current-voltage (I-V) characteristic of this device, even at very low temperatures. We show that the absorption of photons from the high-temperature electromagnetic environment connected to the junction is a possible origin of the single-particle tunneling below the gap. We first consider a N-I-S junction directly coupled to the environment. Then we focus on a circuit where a low-temperature lossy transmission line is inserted between them. For both these circuits, we analyze analytically and numerically the subgap leakage current. We find, in particular, that it is exponentially suppressed as the length and the resistance per unit length of the line are increased. Then, we go beyond the single N-I-S junction considering a hybrid single-electron transistor (SET) constituted by a gate-controlled normal-metal island (N) connected to two voltage-biased superconducting leads (S) by means of two tunnel junctions (S-I-N-I-S). A controlled single-electron current flows between the two superconductors by properly changing in time the gate potential of N. In principle, the Andreev reflection, i.e., the tunneling of two electrons from N to S can be ideally suppressed when the charging energy of N is larger than the energy gap of S. Actually, in real experiments, this two-particle tunneling process also contributes to the total current through the SET. We show that the exchange of photons between the S-I-N-I-S device and the high-temperature electromagnetic environment where it is embedded makes the Andreev reflection energetically possible. We discuss how this effect limits the single-electron tunneling accuracy needed for metrological applications. Next, we focus on the thermodynamical features of the superconductor-based tunnel junctions. We first consider the well-known electronic cooling capabilities of the S1-I-N-I-S1 and S2-I-S1-I-S2 double-junction devices, where S2 and S1 are superconductors with different energy gaps. Then, we study the design and operation of an electronic nanorefrigerator based on a combination of these two structures, i.e., a cascade cooler. We show numerically that a normal-metal island can be cooled down to about 100 mK starting from a bath temperature of 500 mK. We discuss the practical implementation, potential performance and limitations of such a device. Finally, we consider the dynamics of a quantum phase-slip junction (QPSJ) connected to a microwave source. With respect to an ordinary Josephson junction, a QPSJ can sustain dual Shapiro steps, consisting of well-defined current plateaus at multiple integers of the microwave frequency in the I-V characteristic. Their experimental observation has been elusive up to now. We argue that thermal and quantum fluctuations can smear the I-V curve considerably. To understand these effects, we determine the I-V characteristic of a current-biased QPSJ under microwave irradiation and connected to an inductive and resistive environment. We find that the effect of these fluctuations is governed by the resistance of the environment and by the ratio of the phase-slip energy and the inductive energy. Our results are of interest for experiments aimed at the observation of dual Shapiro steps in QPSJ devices for the definition of the quantum current standard
Blanc, Xavier. „Equations aux dérivés partielles elliptiques non linéaires. Applications à la modélisation des solides et aux condensats de Bose-Einstein“. Habilitation à diriger des recherches, Université Pierre et Marie Curie - Paris VI, 2005. http://tel.archives-ouvertes.fr/tel-00136839.
Der volle Inhalt der QuelleLa base de travail des chapitres 1, 2 et 3 est le modèle de Thomas-Fermi-von Weizsäcker (TFW), ou certaines de ses extensions. Dans ce modèle, un système moléculaire est décrit par N noyaux, qui sont des particules classiques ponctuelles, et N électrons, qui sont des particules quantiques définies par leur densité collective. L'énergie TFW, qui dépend des positions des noyaux et de la densité électronique, est minimisée par rapport à cette dernière. Ce modèle est défini au départ pour un nombre fini de noyaux et d'électrons, et sa définition pour une infinité de particules est un problème non trivial. Ce problème, dit de limite thermodynamique, consiste à faire tendre conjointement le nombre de noyaux et d'électrons vers l'infini, en imposant une certaine géométrie (typiquement la périodicité) aux noyaux, et à obtenir la convergence de la densité d'électrons, ainsi que de l'énergie moyenne du système. Ce problème a été résolu dans le cas périodique par I. Catto, C. Le Bris et P.-L. Lions.
Le chapitre 1 aborde le problème de la justification de la périodicité supposée dans l'ouvrage de Catto, Le Bris et Lions. Dans la section 1.3, on considère l'énergie TFW d'un cristal comme une fonction du réseau périodique définissant la position des noyaux, et on étudie l'existence d'un minimiseur. Un préliminaire à ce travail, présenté dans la section 1.2, est l'étude des cas dégénérés de réseaux périodiques, à savoir le cas où les noyaux sont répartis périodiquement sur un plan d'une part, et celui où les noyaux sont répartis périodiquement sur une droite d'autre part.
Les sections 1.4 et 1.5 abordent le problème sans supposer la périodicité : on minimise l'énergie TFW par rapport à la densité électronque et par rapport à la position des noyaux, à N fixé, et on démontre alors que quand N tend vers l'infini, la configuration minimisante devient périodique. Ce problème est traité théoriquement pour le cas 1D (section 1.4), puis une étude numérique est faite sur le cas 2D (section 1.5), indiquant que le résultat est aussi vrai dans ce cas.
Bien que la périodicité soit une bonne approximation pour les cristaux simples, il arrive souvent (dans le cas des polycristaux, des solides amorphes ou de solides cristallins présentant des dislocations par exemple) que cette hypothèse ne soit pas valable. C'est pourquoi on étudie dans le chapitre 2 les problèmes de définition du modèle TFW, pour des solides dont les positions de noyaux ne sont pas périodiques. Un cas déterministe est présenté dans la section 2.1.1, où l'on construit le cadre fonctionnel nécessaire à la définition du modèle, puis on résout le problème de limite thermodynamique associé. La section 2.1.2 présente un cas où les positions des noyaux sont stochastiques. Là aussi, on commence par construire un cadre stochastique (stationnaire ergodique) nécessaire, puis on résout le problème de limite thermodynamique correspondant.
Outre ces problèmes de limite thermodynamique, qui font le lien entre un modèle moléculaire et le modèle de théorie des solides correspondant, on étudie dans la section 2.2 des modèles (dits "orbital-free'') plus élaborés utilisés dans certains codes de chimie, sans chercher à les justifier par limite thermodynamique. Cette étude montre que le problème variationnel est mal posé, et que le "minimum'' calculé est un minimum local vraisemblablement dépendant de la discrétisation utilisée et du point de départ de l'algorithme de minimisation.
Le modèle TFW est un modèle microscopique. Il est cependant naturel, après l'avoir défini pour des solides (cristallins ou non), d'étudier le lien de ce modèle avec des modèles d'élasticité non linéaire. Ce problème est évoqué dans le chapitre 3, où on considère l'énergie d'un système atomique déformé par un diffémorphisme u, et on passe à la limite quand la distance inter-atomique tend vers 0. On obtient ainsi une énergie hyperélastique qui a la forme de celles utilisées en mécanique. La section 3.1 présente ce travail dans un cadre déterministe, la section 3.2 le même type de résultat dans le cas où les positions des noyaux sont stochastiques.
La section 3.3 présente une étude similaire, mais dans le cas d'un joint collé, c'est-à-dire d'une interface d'épaisseur nulle au niveau macroscopique (mais infinie au niveau microscopique). Ce cas est particulier car il doit autoriser un saut de la déformation à travers l'interface, ce qui lui impose une régularité moindre que précédemment.
Dans le même esprit, la section 3.4 présente l'analyse du couplage entre un modèle de mécanique des milieux continus et le modèle discret correspondant. L'idée est ici d'étudier la déformation d'un solide qui est régulière dans une partie du solide, mais présente des singularités. Là où la déformation est régulière, on utilise un modèle d'élasticité standard, et là où la déformation est singulière, on revient au modèle discret mettant en jeu les atomes et leurs interactions. Comme à notre connaissance aucune étude théorique n'existait sur ce type de théorie, nous avons étudié un cas très simple de dimension 1, et obtenu des résultats qui laissent penser que le modèle est "bon'' dans le cas convexe (i.e si le potentiel d'interaction des atomes est convexe), mais beaucoup plus douteux dans le cas contraire.
Le chapitre 4 présente des travaux sur les condensats de Bose-Einstein. La première section porte sur l'écoulement d'un condensat autour d'un obstacle (physiquement, un laser). Nous établissons l'existence d'une solution sans vortex si la vitesse de translation de l'obstacle est suffisamment faible. Ce résultat avait déjà été établi pour un modèle de dimension 2, et nous l'avons étendu au cas plus réaliste de dimension 3, en étudiant en particulier la zone du bord du condensat où le modèle 2D n'est pas valable (contrairement au coeur du condensat).
La section 4.3 concerne l'étude de condensats en rotation, et en particulier des vortex nucléés par cette rotation. Les résultats présentés portent sur la rotation rapide : si Omega est la vitesse de rotation, le système n'a de minimum d'énergie que si Omega < 1. La rotation rapide correspond à la limite Omega tend vers 1. Dans ce régime, la fonction d'onde peut être approximée avec une bonne précision par une fonction analytique multipliée par une gaussienne. Les vortex sont alors les zéros de cette fonction. Nous établissons une borne supérieure de l'énergie en utilisant une fonction test dont les zéros forment un réseau distordu sur les bords du condensat. Ceci est en accord avec les observations expérimentales et numériques.
Macé, Nicolas. „Propriétés électroniques des quasicristaux“. Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS313/document.
Der volle Inhalt der QuelleWe consider the problem of a single electron on one and two-dimensional quasiperiodic tilings. We first introduce quasiperiodic tilings from a geometrical point of view, and point out that among aperiodic tilings, they are the closest to being periodic. Focusing on one of the simplest one-dimensional quasiperiodic tilings, the Fibonacci chain, we show, with the help of a renormalization group analysis, that the multifractality of the electronic states is a direct consequence of the scale invariance of the chain. Considering now a broader class of quasiperiodic chains, we study the gap labeling theorem, which relates the geometry of a given chain to the set of values the integrated density of states can take in the gaps of the electronic spectrum. More precisely, we study how this theorem is modified when considering a sequence of approximant chains approaching a quasiperiodic one. Finally, we show how geometrical height fields can be used to construct exact eigenstates on one and two-dimensional quasiperiodic tilings. These states are robust to perturbations of the Hamiltonian, provided that they respect the symmetries of the underlying tiling. These states are critical, and we relate their fractal dimensions to the probability distribution of the height field, which we compute exactly. In the case of quasiperiodic chains, we show that the conductivity follows a scaling law, with an exponent given by the same probability distribution
Muller, Christophe. „Relations structure-activité pour le métabolisme et la toxicité“. Phd thesis, Université de Strasbourg, 2013. http://tel.archives-ouvertes.fr/tel-00834868.
Der volle Inhalt der QuelleNambully, Suresh Kumar. „A Filtered-Laminar-Flame PDF subgrid scale closure for LES of Premixed Turbulent Flames : Application to a Stratified Bluff-body burner with Differential Diffusion“. Electronic Thesis or Diss., Rouen, INSA, 2013. http://www.theses.fr/2013ISAM0014.
Der volle Inhalt der QuelleA sub-grid scale closure for Large Eddy Simulation (LES) of turbulent combustion, based on physical space filtering of laminar flames is presented. The proposed formalism relies on a presumed probability density function (PDF) derived from the filtered laminar flames and flamelet tabulated chemistry. The combustion LES filter size is not fixed in this novel approach when sub-grid scale wrinkling occurs, but calibrated depending on the local level of unresolved scalar fluctuations. The model was validated by simulating 1D filtered laminar flames and 2D Bunsen flames. Subsequently, the model was tested on a 3D turbulent scenario by performing LES of the premixed and stratified configurations of the Cambridge swirl burner, experimentally studied by Sweeney and co-workers. Comparison of simulation and experiments for both the premixed and stratified configurations showed good agreement emphasizing the model characteristiscs. Instantaneous and time averaged LES data were analyzed to extract
Squizzato, Davide. „Exploring Kardar-Parisi-Zhang universality class : from the dynamics of exciton-polariton condensates to stochastic interface growth with temporally correlated noise“. Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAY043.
Der volle Inhalt der QuelleIn this thesis we study the Kardar-Parisi-Zhang (KPZ) equation in two different physical systems. The first is an out-of-equilibrium condensate of Exciton-Polaritons, which are quasi-particle excitations stemming from the interaction between confined photons and excitons. A mapping between the dynamics of the phase of the condensate and the KPZ dynamics was predicted in the literature. By using a model and parameters close to real experimental setups, we show that in excitons polaritons the distributions of the phase of the condensate follows the law predicted by KPZ equation and that KPZ universal properties are indeed observable in actual experimental systems in one dimension. Furthermore we generalize the mapping to inhomogeneous systems, in which confinement, disorder and thermally activated phonons are taken into account. The second physical systems we investigate are classical growing surfaces whose underlining microscopic dynamics involves temporal correlations in time. These phenomena are described by a KPZ equation wherethe noise is temporally correlated. This correlation breaks one of the founding symmetry of KPZ equation and leads to a possible new fixed point. Using non-perturbartive renormalization group (NPRG) technique we study both short and long range temporally correlated systems in one and two dimensions. In the one-dimensional case we show that the pure KPZ fixed point persists both in the short range and in the long range, up to a critical value of the correlation exponent. This clarifies a long lasting debate on the effects of infinitesimal time correlation inKPZ equation. In two dimensions we find a similar picture. No other results, except for a one-loop perturbative calculation existed in the literature for two dimensions
Luca, Aurélie de. „Espaces chimiques optimaux pour la recherche par similarité, la classification et la modélisation de réactions chimiques représentées par des graphes condensés de réactions“. Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAF027.
Der volle Inhalt der QuelleThis thesis aims to develop an approach based on the Condensed Graph of Reaction (CGR) method able to (i) select an optimal descriptor space the best separating different reaction classes, and (ii) to prepare special descriptors to be used in obtaining predictive structure-reactivity models. This methodology has been applied to similarity search studies in a database containing 8 different reaction classes, and to visualization of its chemical space using Kohonen maps and Generative Topographic Mapping. Another part of the thesis concerns development of predictive models for pKa and for optimal conditions for different types of Michael reaction involving both CGR-based and Electronic Effect Descriptors
Désert, Anne. „Contribution à l'étude des propriétés structurales vibrationnelles et magnétiques du composé bidimensionnel KFeF4“. Le Mans, 1990. http://www.theses.fr/1990LEMA1013.
Der volle Inhalt der QuellePetit, Xavier. „Etude de l'interaction cinétique chimique/turbulence dans une flamme cryotechnique LOx/CHA4“. Phd thesis, INSA de Rouen, 2014. http://tel.archives-ouvertes.fr/tel-01020523.
Der volle Inhalt der QuelleLours, Thierry. „Etude structurale de la transformation sol-gel : caractérisation des aérogels et étude de leur densification par diffusion des rayons X aux petits angles“. Montpellier 2, 1989. http://www.theses.fr/1989MON20012.
Der volle Inhalt der QuelleCastel, Alexis. „Comportement vibratoire de structures composites intégrant des éléments amortissants“. Phd thesis, Université de Bourgogne, 2013. http://tel.archives-ouvertes.fr/tel-00983378.
Der volle Inhalt der QuelleNambully, Suresh Kumar. „A Filtered-Laminar-Flame PDF subgrid scale closure for LES of Premixed Turbulent Flames : Application to a Stratified Bluff-body burner with Differential Diffusion“. Phd thesis, INSA de Rouen, 2013. http://tel.archives-ouvertes.fr/tel-00845904.
Der volle Inhalt der QuelleFajraoui, Noura. „Analyse de sensibilité globale et polynômes de chaos pour l'estimation des paramètres : application aux transferts en milieu poreux“. Phd thesis, Université de Strasbourg, 2014. http://tel.archives-ouvertes.fr/tel-01019528.
Der volle Inhalt der QuelleDuret, Benjamin. „Simulation numérique directe des écoulements liquide-gaz avec évaporation : application à l'atomisation“. Phd thesis, INSA de Rouen, 2013. http://tel.archives-ouvertes.fr/tel-00971810.
Der volle Inhalt der QuelleEnjalbert, Nicolas. „Modélisation avancée de la combustion turbulente diphasique en régime de forte dilution par les gaz brûlés“. Phd thesis, INSA de Rouen, 2011. http://tel.archives-ouvertes.fr/tel-00735875.
Der volle Inhalt der QuelleJlassi, Sarra. „Formulation et études des problèmes de commande en co-manipulation robotique“. Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-00982969.
Der volle Inhalt der QuelleSouilem, Inès. „Élaboration de miniémulsions dans un nouveau mélangeur à écoulement élongationnel : influence des paramètres du procédé et de la formulation“. Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00864095.
Der volle Inhalt der QuelleHage, Hassan Maya. „Méthodologies de conception optimale de systèmes de conversion électromécanique“. Phd thesis, Université Paris Sud - Paris XI, 2014. http://tel.archives-ouvertes.fr/tel-01002008.
Der volle Inhalt der QuelleTejedor, Vincent. „Random walks and first-passage properties : trajectory analysis and search optimization“. Phd thesis, Université Pierre et Marie Curie - Paris VI, 2012. http://tel.archives-ouvertes.fr/tel-00721294.
Der volle Inhalt der QuelleHameurlaine, Kheira. „Contribution à l'étude d'un arc électrique de faible puissance“. Phd thesis, Université d'Orléans, 2012. http://tel.archives-ouvertes.fr/tel-00821030.
Der volle Inhalt der QuelleMoutanabbi, Mohammed. „Calculs cristallographiques liés à l'étude de lames de grenats epitaxies“. Besançon, 1987. http://www.theses.fr/1987BESA2024.
Der volle Inhalt der QuelleSeisson, Gabriel. „Etude expérimentale et théorique de l'endommagement du graphite sous sollicitation dynamique - Application aux impacts hypervéloces“. Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2014. http://www.theses.fr/2014ESMA0015/document.
Der volle Inhalt der QuelleComposite materials are widely used in various applications and may be submittedto hypervelocity impacts (HVI), such as in the aerospace field. The size of the impactors beingclose to that of a strand of fibers, mesoscopic simulations are of great interest but they need reliablenumerical models for each meso-Constituent. Graphite often being used as fiber or matrix,we studied its dynamic behavior. Penetration and craterization experiments have been conductedonto porous isotropic graphite. Post-Mortem analysis of targets, associated to order-Of-Magnitudecalculations, sheds a new light on the phenomenology of impacts and brings useful informationfor numerical simulation. A model for porous and brittle materials, implemented into a hydrocode,is used. Partially based on static mechanical properties, it has been progressively tested on planeshocks. Its use for simulating HVI gives satisfying results. Nevertheless, it was necessary to validateit by disregarding the projectile behavior. In that purpose, a campaign of laser-Driven shocks hasbeen conducted. In-Situ diagnostics have been simultaneously used and their correlation with postmortemanalysis allowed the identification of different damaging regimes of the targets. Finally,although the equivalence between HVI and laser-Driven shocks is not proved, the latter turned outto be complementary, suggesting the future evolutions of the numerical model
Bouschbacher, Fabien. „Des coordonnées de décalage sur le super espace de Teichmüller“. Phd thesis, Université de Strasbourg, 2013. http://tel.archives-ouvertes.fr/tel-00963569.
Der volle Inhalt der QuellePant, Dibakar Raj. „Line element and variational methods for color difference metrics“. Phd thesis, Université Jean Monnet - Saint-Etienne, 2012. http://tel.archives-ouvertes.fr/tel-00981484.
Der volle Inhalt der QuelleElmi, Robleh Hassan. „Modélisation numérique des écoulements pulmonaires“. Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00766647.
Der volle Inhalt der QuelleMériaux, François. „Théorie des jeux et apprentissage pour les réseaux sans fil distribués“. Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-00952069.
Der volle Inhalt der QuelleDelhorme, Maxime. „Thermodynamics and Structure of Plate-Like Particle Dispersions“. Phd thesis, Université de Bourgogne, 2012. http://tel.archives-ouvertes.fr/tel-00818964.
Der volle Inhalt der QuelleTchomgo, Felenou Emmanuel. „Cartographie unifiée de la dynamique des solitons dans les guides d'onde à fibre optique“. Phd thesis, Université de Bourgogne, 2013. http://tel.archives-ouvertes.fr/tel-00945451.
Der volle Inhalt der QuelleNguyen, Trong Giang. „Modélisation du comportement rhéologique d'alliages à l'état semi-solide“. Grenoble INPG, 1991. http://www.theses.fr/1991INPG0122.
Der volle Inhalt der QuellePalade, Adrian-Ciprian. „Caractérisation du comportement mécanique de la sous surface d'un polymère percé, sous une sollicitation de type hertzienne“. Phd thesis, Université de Bourgogne, 2013. http://tel.archives-ouvertes.fr/tel-00960291.
Der volle Inhalt der QuelleZidane, Ali. „Risk of subsidence and aquifer contamination due to evaporite dissolution : modelization of flow and mass transport in porous and free flow domains“. Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00867207.
Der volle Inhalt der QuelleDos, Santos Fabien. „Contribution à l'étude de la formation des sprays“. Phd thesis, Université de Bourgogne, 2012. http://tel.archives-ouvertes.fr/tel-00869635.
Der volle Inhalt der QuelleAssemat, Élie. „Sur le rôle des singularités hamiltonniennes dans les systèmes contrôlés : applications en mécanique quantique et en optique non linéaire“. Phd thesis, Université de Bourgogne, 2012. http://tel.archives-ouvertes.fr/tel-00833905.
Der volle Inhalt der QuellePougaza, Doriano-Boris. „Utilisation de la notion de copule en tomographie“. Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00684637.
Der volle Inhalt der QuelleMerheb, Rania. „Fiabilité des outils de prévision du comportement des systèmes thermiques complexes“. Phd thesis, Université Sciences et Technologies - Bordeaux I, 2013. http://tel.archives-ouvertes.fr/tel-00969036.
Der volle Inhalt der QuelleBen, Nasr Ouissem. „Numerical simulations of supersonic turbulent wall-bounded flows“. Phd thesis, INSA de Rouen, 2012. http://tel.archives-ouvertes.fr/tel-01059805.
Der volle Inhalt der QuellePrigent, Guillaume. „Modélisation et simulation numérique d'écoulements diphasiques pour la microfluidique“. Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-01059794.
Der volle Inhalt der QuelleBenslimane, Abdelhakim. „Rhéologie et écoulement de fluides chargés : application aux réseaux d'assainissement urbains : étude expérimentale et modélisation“. Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00804350.
Der volle Inhalt der QuelleJiang, Jian. „Modeling of complex network, application to road and cultural networks“. Phd thesis, Université du Maine, 2011. http://tel.archives-ouvertes.fr/tel-00691129.
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