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On Nested Sequents for Constructive Modal Logics
No full textInternational audienceWe present deductive systems for various modal logics that can be obtained from the constructive variant of the normal modal logic CK by adding combinations of the axioms d, t, b, 4, and 5. This includes the constructive variants of the standard modal logics K4, S4, and S5. We use for our presentation the formalism of nested sequents and give a syntactic proof of cut elimination
TRIQS: A toolbox for research on interacting quantum systems
No full textInternational audienceWe present the TRIQS library, a Toolbox for Research on Interacting Quantum Systems. It is an open-source, computational physics library providing a framework for the quick development of applications in the field of many-body quantum physics, and in particular, strongly-correlated electronic systems. It supplies components to develop codes in a modern, concise and efficient way: e.g. Green's function containers, a generic Monte Carlo class, and simple interfaces to HDF5. TRIQS is a C++/Python library that can be used from either language. It is distributed under the GNU General Public License (GPLv3). State-of-the-art applications based on the library, such as modern quantum many-body solvers and interfaces between density-functional-theory codes and dynamical mean-field theory (DMFT) codes are distributed along with it
Fiscal Devaluations in a Monetary Union and the Extensive Margin of Trade
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Experimental and Numerical Study of the Influence of String Mismatch on the Yield of PV Modules Augmented By Static Planar Reflectors
No full textInternational audiencePhotovoltaic (PV) modules are generally installed by the application of empirical rules aimed at reducing shadows during the periods of high solar irradiation. A traditional installation on a horizontal surface results in largely spaced rows of modules with a relatively low tilt angle. The addition of inter-row reflectors results in more direct and diffuse flux transmitted to the cells. The " Aleph " (Amélioration de l'Efficacité Photovolta¨que) project aims to define clear rules for optimal settings of systems of PV module rows with fixed inter-row planar reflectors in a given location and under a given climate. Two PV technologies are tested for performance with this type of system: amorphous silicon (a-Si) and polycrystalline silicon (p-Si). This work combines experiments on panel behavior in an outdoor environment on the SIRTA (Site Instrumental de Recherche par Télédétection Atmosphérique) meteorology platform and a multiphysics numerical model used to couple all the important physical phenomena and accurately describe the system behavior. The model includes a ray tracing radiation/optics module based on the Monte-Carlo method, as well as an electrical module simulated in SPICE. This work presents the influence of the string mismatch losses, present at periods of heterogeneous illumination, on the yield of PV modules augmented by static planar reflectors
Boosting light emission from Si-based thin film over Si and SiO_2 nanowires architecture
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A convergent, modular access to α-chloro-trifluoromethyl derivatives and to 1,1-difluoroalkenes
No full textInternational audienceAn efficient protocol for the preparation of S-(1-chloro-2,2,2-trifluoroethyl)-O-ethyl xanthate is reported. This reagent serves as a versatile precursor of highly functionalized gem-difluoroalkenes through various inter- and intramolecular radical reactions and subsequent reduction with activated magnesium metal. (C) 2014 Elsevier Ltd. All rights reserved
Simulations des effets des écoulements sur la croissance cristalline d'un mélange binaire. Approche par méthode de Boltzmann sur réseau
No full textPhase field models are powerful tools to simulate the interface evolution of crystals, such as those encountered in the vitrification process of radioactive wastes. The purpose of this work is to study the hydrodynamic effects on crystal growth of a binary mixture. An original numerical method, called the Lattice Boltzmann Method (LBM) is adapted and extended for solving and simulating the model of solidification. The LBM is a very attractive method to simulate hydrodynamic problems and we use it for simulating the coupling between the problem of phase change and fluid mechanics. Moreover, we derive a new model to take into account the density change which occurs during the solidification. The PhD thesis will focus on seven main chapters. The first one will introduce the context and motivations of this work. The second chapter is devoted to the phase field models. We will remind the basic assumptions of the models and the physical effects considered here. The third chapter describes the numerical resolution of these models by the LB method. Next, in chapter four, we will present the different validations carried out in this work. Chapter five will present some simulations relative to various solidification processes. One of them, will focus on the crystal growth and the hydrodynamic effect on the crystal shape. Chapter six will be devoted to the development of a new model of coupling between the solidification and the fluid flow. This model will take into account the density change during the solidification. Last chapter will conclude this work of thesis by opening a few perspectives.Les modèles à champ de phase sont des outils puissants pour simuler l'évolution d'interface de cristaux, tels que ceux rencontrés dans le procédé de vitrification de déchets radioactifs du CEA. Le but de ce travail est d'étudier les effets hydrodynamiques sur la croissance des cristaux d'un mélange binaire. Une méthode numérique originale, appelée la méthode de Boltzmann sur réseaux (Lattice Boltzmann en anglais -- LB), est adaptée et étendue pour la résolution et la simulation de modèles de solidification. La méthode LB est une méthode très attractive pour simuler des problèmes hydrodynamiques et nous l'utilisons pour simuler à la fois le problème de changement de phase et la mécanique des fluides. De plus, on établit un nouveau modèle qui tient compte de la variation de densité au cours du changement de phase. Cette thèse s'articule autour de sept chapitres principaux. Le premier introduit le contexte et les motivations de ce travail. Le deuxième chapitre est consacré aux modèles à champ de phase. On rappellera ici les hypothèses de base des modèles et les effets physiques pris en compte dans ce travail. Le troisième chapitre décrit la résolution numérique de ces modèles par la méthode LB. Ensuite, dans le chapitre quatre, on présente différentes validations réalisées au fur et à mesure du développement des modèles. Le chapitre cinq montre plusieurs simulations dont celles relatives à la croissance cristalline et de l'effet d'un écoulement forcé sur cette croissance. Le chapitre six est consacré à l'élaboration d'un nouveau modèle de couplage entre la solidification et l'hydrodynamique en tenant compte de la variation de densité qui se produit au cours de la solidification. Enfin un dernier chapitre viendra conclure ce travail de thèse en ouvrant sur quelques perspectives
Measurement of a subpicosecond coherence time in a quasi-steady-state XUV laser
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Developmental Partial Differential Equations
No full textInternational audienceIn this paper, we introduce the concept of DevelopmentalPartial Differential Equation (DPDE), which consists of aPartial Differential Equation (PDE) on a time-varying manifoldwith complete coupling between the PDE and the manifold’sevolution. In other words, the manifold’s evolution depends onthe solution to the PDE, and vice versa the differential operatorof the PDE depends on the manifold’s geometry. DPDE is usedto study a diffusion equation with source on a growing surfacewhose growth depends on the intensity of the diffused quantity.The surface may, for instance, represent the membrane of anegg chamber and the diffused quantity a protein activating asignaling pathway leading to growth. Our main objective is toshow controllability of the surface shape using a fixed sourcewith variable intensity for the diffusion. More specifically, welook for a control driving a symmetric manifold shape to anyother symmetric shape in a given time interval. For the diffusionwe take directly the Laplace-Beltrami operator of the surface,while the surface growth is assumed to be equal to the value ofthe diffused quantity. We introduce a theoretical framework,provide approximate controllability and show numerical results.Future applications include a specific model for the oogenesisof Drosophila melanogaster