Дисертації з теми "Excitation dynamique"
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Halley, Clara. "La dynamique du traitement de l'excitation à l'adolescence : étude comparative de deux groupes d'âge : éclairage de la clinique projective." Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCB206.
Adolescence, marked by the emergence of puberty and the resurgence of sexual and aggressive drives, engages an internal work linked to psychic transformations and to the emergence of genital sexuality. Puberty can therefore intrude and cause trauma, hurting the subject who is more or less ready to bear the constraint to change induced by the pubertal process. In reference to the theoretical psychoanalytic model, we are interested in the study of the way in which adolescents are confronted with the influx of excitations, both external and internal, through a psychic treatment, by a work of mentalisation and symbolisation, or behavioural, or somatic, by the language of the body or the use of sensoriality. Indeed, whatever the mental capacity of the adolescent, a transient vulnerability of the mental apparatus is expected at this age of life. Our work thus proposes to explore the treatment of excitation in adolescence, evidenced by the study of the quality of several psychic movements: narcissism, protective-shield system, sensoriality and body language, as well as the processes of thought through the study of mentalisation and symbolisation. Our research object thus questions the quality of the treatment of excitation, through the putting into perspective of these four conceptual dimensions, likely to expose a better process approach of adolescence. On the basis of the main hypothesis that the processing of the excitation is multifactorial, the objective of this study is to determine how the articulation of the different concepts studied is able to account more sensibly for the treatment of excitation in adolescence. The projective methodology was chosen to test this hypothesis using grids referred to the above four dimensions. We met 17 teenagers aged 14 to 18 years old who passed the Rorschach and TAT. In a comparative approach, we studied the treatment of excitation with two age groups (14-16 years and 16-18 years). The results highlight differences in the treatment of adolescent arousal between the two age groups, with the younger ones preferring inhibition, the older age groups being more able to mentalise and symbolize the excitation. According to our general hypothesis, the projective analysis of the four dimensions of our work allows a finer approach for each adolescent to the specificities of the treatment of excitation
Lique, François. "Excitation collisionnelle de molécules d'intérêt astrophysique : théorie et interprétation d'observations." Paris 6, 2006. https://tel.archives-ouvertes.fr/tel-00172004.
Mabilia, Antoine. "Dynamique non-linéaire d'une soufflante en rotation." Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEC026.
In an aeronautics industry increasingly concerned by the environmental issues of our time, the mastery of dynamic behavior is of particular interest in terms of compliance with the environmental legislation. Indeed, this allows the structures to be designed as accurately as possible and therefore optimizes the total weight of the turbojet engine, while maintaining an exemplary level of reliability and safety as well as excellent performances. Fully integrated into this theme, the problematics of mistuning and nonlinear dynamics are eminently studied by present academic research, leading to the development of numerical methods that allow these two effects to be taken into account simultaneously. However, the representativity of these numerical methods with respect to the behavior of an actual engine can hardly be evaluated because of the few tests available in the literature. In addition to improving the understanding and prediction of bladed disks vibratory phenomena, this doctoral work has a twofold objective: experimental and numerical. The latter aimed at investigating the representativity of numerical models and methods, particularly developed at the LTDS on the problematics of mistuning and nonlinear dynamics, in comparison with rotating tests on a latest-generation industrial fan made of composite materials. For this purpose, the PHARE#1 test bench, developed over the last few years at the LTDS, allows the testing of bladed disks on a 1:1 scale, rotating in vacuum, while exciting the blades by means of piezoelectric actuators. The numerical methods used to simulate the fan are based on the concept of substructuring associated with a triple modal synthesis, thus allowing the consideration of mistuning within nonlinear problems of industrial size. Two case studies, both experimental and numerical, were conducted and analyzed during this doctoral work. These studies exploit an excitation by means of piezoelectric actuators whose modeling required the development of an electrical degrees of freedom condensation technique in order to benefit from the numerical methods of purely mechanical reduction and resolution. The first study has been carried out on a fan blade embedded in clamping jaws. This application made possible to focus on the nonlinear aspects of contact and friction at the dovetail by comparing the test results and the numerical simulations. The second study was performed on the composite bladed fan rotating in vacuum, thus achieving analyses and comparisons concerning the mistuning of the response and modal shapes coupled with nonlinear effects. The results obtained show a very good representativity of the numerical simulations with respect to the rotating tests in terms of mistuning, especially with respect to the decompositions in diameter components and the spatial distributions of the vibration amplitudes of the blades
Dubanet, Olivier. "Dynamique des interactions entre excitation et inhibition périsomatique dans le circuit hippocampique normal et épileptique in vivo." Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0259.
The hippocampus is a key structure for learning and memory. The function of this neuronal circuit is based on complex interactions between excitatory glutamatergic pyramidal cells and various types of inhibitory GABAergic interneurons. The precise roles fullfiled by interneuron subtypes is still unclear because it is challenging to study in vivo the inhibitory function of specific interneurons. Alterations of the synaptic interactions between pyramidal cells and interneurons in the hippocampus also underlie neurological pathologies such as epilepsy, neurodevelopmental diseases such as autism, or neurodegenerative diseases such as Alzheimer's disease. Among the different types of interneurons, those that express parvalbumin (PV) and project to pyramidal cell bodies (perisomatic inhibition) are particularly efficient in blocking action potential generation in their target cells. PV interneurons therefore play a central role in neuronal coding (by controlling which cell can fire or not) but also in the balance between global excitation and inhibition within the circuit, prevention runaway excitation between interconnected pyramidal cells and the generation of epileptic seizure. Functional perisomatic inhibition directly depends on Cl- electrochemical gradient, or the interaction between membrane potential and Cl- distribution across the membrane of the target neuron. However, these parameters change continuously during neuronal activity, and it has been shown that the Cl- gradient can be reversed, resulting in paradoxically excitatory GABAergic transmission. This phenomenon, which contributes to the physiological maturation of neuronal circuits during early development, is also considered as a major source of neuronal circuit dysfunction in various pathologies such as epilepsy, autism or schizophrenia. This field of research is therefore clinically relevant, and the research for drugs restoring a physiological Cl- gradient is very active. However, a direct assessment of the excitatory GABA hypothesis has been hindered by the technical difficulty of probing endogenous GABAergic synaptic function in vivo, and contradictory data in the literature call for a direct evaluation. During my PhD, using electrophysiological, opto- and pharmaco-genetic techniques, I have contributed to develop a new and sophisticated methodological approach to evaluate the perisomatic GABAergic transmission in the hippocampus, respecting the complexity of spontaneous neuronal activity dynamics in vivo. I have studied the functional role of perisomatic inhibition from PV interneurons in the adult hippocampal circuit, in physiological conditions and in two models of epileptic mice in which I was able to detect an excitatory GABAergic transmission in vivo. However, excitatory GABA was unlikely to participate in epileptogenesis because it was expressed only during the period of post-ictal silence after acute seizures, or in a potentially negligible minority of pyramidal cells one week post-status epilepticus during the latent period that precedes the emergence of chronic epilepsy, a stage during which I also demonstrated that the majority of CA3 pyramidal neurons were no longer under perisomatic inhibitory control. In addition to contribute to a better understanding of epileptogenesis, this approach constitutes an invaluable tool to quantify the actual in vivo efficacy of drugs designed to modulate Cl- homeostasis and restore physiological GABAergic inhibition, thereby meeting high clinical and therapeutical expectations
Ajili, Yosra. "Etude de la dynamique d'excitation ro-vibrationnelle de molécules d'intérêt astrophysique par collision avec He ou H2." Thesis, Paris Est, 2014. http://www.theses.fr/2014PEST1057/document.
The main goal of this work is to examine the capabilities of explicitly correlated coupled cluster (CCSD(T)-F12) methods for the mapping of multidimensional potential energy surfaces (PESs) at short, medium and long intermolecular ranges and therefore their use in the determination of accurate collisional data for a wide range of collision energies after dynamical computations. This is done through close comparisons of these PESs and corresponding data to those deduced using standard coupled cluster approaches with perturbative treatment of triple excitations (CCSD(T)). Therefore, we definitely establish that CCSD(T)-F12 in connection with the aug-cc-pVTZ basis set is the method of choice for the generation of such accurate PESs with strong reduction of computational cost (CPU and disk occupancy). As a benchmark, we treated the rotational excitation induced by collision of HCl/DCl-He and CO2 -CO2 van der Waals molecular systems, which are relevant for astrophysics and planetary atmospheres, respectively. For HCl-He and DCl-He, we closely compared the results deduced from PESs calculated with explicitly correlated and standard coupled cluster methods. These PESs were generated over the intermonomer degrees of freedom. Through these comparisons, we have shown that the use of explicitly correlated CCSD(T)-F12/aug-cc-pVTZ method overcomes the accuracy of the reference approach CCSD(T) associated with the complete basis set (CBS) with a very low computational cost (2 orders of magnitude less). The quality of the explicitly correlated potential surface was verified by cross sections and collision rate calculations. Then, we extended our findings to the CO2 -CO2 larger molecular systems. Hence, we generated four-dimentional (4D) PES of the carbon dioxide dimer (CO2 )2 using the CCSD(T)-F12 method and we compared it with other surfaces specially with that generated by the CCSD(T)/CBS and SAPT approaches. Again, we established the performance of explicitly correlated method to account fully for electron correlation. This was validated after dynamical calculations, where second virial coefficient, first spectral moment and vibrational energies of the CO2 dimer were computed and compared to previous experimental and theoretical data. In total, we recommend the use of CCSD(T)/aug-cc-pVTZ method for the investigation of weak interactions occurring between polyatomic-polyatomic systems for a wide range of applications
Renucci, Pierre. "Dynamique des polaritons de microcavité : cohérences optiques, cohérences de spin." Toulouse, INSA, 2001. http://www.theses.fr/2001ISAT0020.
This thesis is a contribution to the study, via ultrafast time-resolved optical spectroscopy, of optical and spin coherence phenomena involving polaritons in semiconductor microcavities. Coherent control of spin and population of polaritons is performed and we show that the scattering processes responsible for the loss of optical coherence are less efficient when the quasi-particule exhibits a strong photonic character. At low density, the analysis of spin coherences evidences a quenching of spin and alignment relaxation processes for negative detuning. At higher density, a strong non-linear mechanism is observed in the strong coupling regime. This effect is interpreted as stimulated parametric scattering, a coherent process which relies on a bosonic approach of interacting polaritons. Under transverse magnetic field, spin quantum beats are observed. Under resonant excitation, an electron-hole spin correlation is evidenced. To finish with, we show that the absolute value of the effective transverse electron Landé factor increases with the excitonic character of the quasi-particule
Lique, François. "Excitation collisionnelle de molécules d'intérèt astrophysique : théorie et interprétation d'observations." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2006. http://tel.archives-ouvertes.fr/tel-00172004.
Frindi, Mohammed. "Etude dynamique des nonlinearites optiques de cucl en regime impulsionnel nanoseconde." Université Louis Pasteur (Strasbourg) (1971-2008), 1987. http://www.theses.fr/1987STR13116.
Mathieu, Cécile. "Régime de conduction métallique des fluides coulombiens métal alcalin-halogénure alcalin : structure et dynamique." Lyon 1, 1987. http://www.theses.fr/1987LYO10143.
Ait, Younes Tarik. "Calcul de la réponse dynamique de grands domaines à une excitation acoustique par une méthode de sous domaines." Compiègne, 1999. http://www.theses.fr/1999COMP1248.
Morey, Etienne. "Purge, excitation dynamique et structuration des disques de débris soumis à l'interaction gravitationnelle de planètes et d'étoiles voisines." Phd thesis, Observatoire de Paris, 2013. http://tel.archives-ouvertes.fr/tel-00917968.
Morey, Etienne. "Purge, excitation dynamique et structuration des disques de débris soumis à l'interaction gravitationnelle de planètes et d'étoiles voisines." Phd thesis, Observatoire de Paris (1667-....), 2013. http://www.theses.fr/2013OBSP0235.
A debris disk around a main sequence star is made of planetesimals, which are the remnant of the planet formation process according to the core-accretion theory. In the Solar system, the main asteroid belt and the Kuiper belt are examples of debris disks. Around other stars, debris disks are observable if they are massive enough for collisions between planetesimals to produce continuously enough dust to be detected, by their thermal emission in the far infrared, or by scattered light in the visible spectrum. In this work, we have studied the stripping, the dynamical excitation and the structuring of debris disksundergoing the gravitational interaction with a planet inside a system, a stellar companion in a binary system, and a passing star in the dense environment of an open cluster during the first 100 millions years after the birth of the star. We have addressed these problems by the numerical simulation of the dynamics of a disk of planetesimals in these various conditions. We have finally carried out a study to determine the characteristics of the debris disk population around stars of different types, with the standard collisional evolution model, our results about dynamical excitation of disks and the data of the Spitzer surveys. We show that the lack of debris disks detected around low mass M type stars can be explained by planetesimals 10 times smaller than around solar type or more massive stars
Shihab, Sylvain. "Excitation et détection optiques de la dynamique de l’aimantation dans le semi-conducteur ferromagnétique (Ga,Mn)(As,P)." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066548/document.
Development of impulsional laser enhanced the study of the magnetization dynamic in the temporal domain (fs-ns) with optical techniques. In thin ferromagnetic films with a weak optical absorption, excitation and optical mechanisms are not yet fully understood. To increase our understanding, variations of magnetic parameters are required. To that end, the magnetic semiconductor like (Ga,Mn)(As,P) are a good choice due to their magnetic properties easily adjustable thanks to the coupling between magnetic and semiconductor properties. In this thesis, conditions for optimal excitations were established. Supposing a thermal excitation origin, we assessed the transient change of temperature and anisotropy constant. I also established the role of the optical absorption and dephasing due to the finite magnetic layer thickness in the spin-waves detection process. The observation of several spin-waves gave me the opportunity to assess the spin-stiffness constant as a function of phosphorus. On the contrary of theoretical prediction, I showed that the spin-stiffness hardly vary with the phosphorus concentration
Shihab, Sylvain. "Excitation et détection optiques de la dynamique de l’aimantation dans le semi-conducteur ferromagnétique (Ga,Mn)(As,P)." Electronic Thesis or Diss., Paris 6, 2015. http://www.theses.fr/2015PA066548.
Development of impulsional laser enhanced the study of the magnetization dynamic in the temporal domain (fs-ns) with optical techniques. In thin ferromagnetic films with a weak optical absorption, excitation and optical mechanisms are not yet fully understood. To increase our understanding, variations of magnetic parameters are required. To that end, the magnetic semiconductor like (Ga,Mn)(As,P) are a good choice due to their magnetic properties easily adjustable thanks to the coupling between magnetic and semiconductor properties. In this thesis, conditions for optimal excitations were established. Supposing a thermal excitation origin, we assessed the transient change of temperature and anisotropy constant. I also established the role of the optical absorption and dephasing due to the finite magnetic layer thickness in the spin-waves detection process. The observation of several spin-waves gave me the opportunity to assess the spin-stiffness constant as a function of phosphorus. On the contrary of theoretical prediction, I showed that the spin-stiffness hardly vary with the phosphorus concentration
Pincet, Lancelot. "Dynamic excitation systems for quantitative and super-resolved fluorescence microscopy." Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASP033.
Single Molecule Localization Microscopy (SMLM) is a super-resolution optical technique enabling the observation of biological samples labeled with fluorescent dyes at resolutions well below the diffraction limit. The quality of this imaging heavily relies on the ability to observe molecules individually, requiring precise control of fluorescent dye photophysics for them to emit with a high sparsity in both space and time. Until now, dynamic excitation methods aimed to produce uniform illumination over large fields (200 um x 200 um). However, these types of illumination encounter difficulties in imaging dense biological samples, such as neurons, where the diversity in dye density prevented the generation of a uniform single molecule regime across the entire observed area. To address this issue, I propose a new approach that dynamically adjusts illumination based on sample density. This method combines a novel tri-dynamic optical excitation system with a feedback loop based on density analysis, benefiting from an in-depth study of fluorescent dye photophysics. The intelligent imaging system, where the excitation pattern varies over time, integrates a 2D scanning system, a variable zoom system, and a laser. This allows for the generation of a variety of dynamically changing illumination patterns to adapt to the observed sample and the density of locally detected localizations. This new approach has been validated on various biological samples. Additionally, the dynamic excitation system has also been explored for live samples imaging techniques, such as MSIM or FRAP
Müller, Markus. "Etude du polariton en cavité en régime de forte excitation : dynamique et non-linéarités dans les microcavités II-VI." Université Joseph Fourier (Grenoble), 2000. http://www.theses.fr/2000GRE10215.
Beaulieu, Nathan. "Propriétés électroniques et magnétiques sous excitation laser femtoseconde, du Gd monocristallin aux alliages ferrimagnétiques." Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-00953656.
Chabrier, Gilles. "Contribution à l'étude des fluides coulombiens : application au cas des mélanges chargés alcalins-halogénures alcalins." Lyon 1, 1985. http://www.theses.fr/1985LYO10046.
Dubard, Jimmy. "Étude de la dynamique des porteurs dans les semi-conducteurs III-V sous excitations optiques." Paris 11, 1986. http://www.theses.fr/1986PA112246.
The subject of this thesis is the study of photoexcited carrier dynamics in III-V semiconductors, particularly in GaAs epitaxial layers and multi quantum wells GaAs-AlGaAs. The technique used is the absorption saturation due to band-filling by carriers. The experimental tools are picosecond and femtosecond lasers. The results show a strong dependance of the phenomena with lattice temperature. On a time scale of 100psec, the evolution of the absorption saturation at room temperature was slow while at 15K the absorption recovery takes place 30psec after the pump pulse. This is confirmed by the carrier life time of about 10psec deduced from the transmission curves at low temperature. This short time could be explained by stimulated photon emission in the plane of the layers. It is along this direction that the interaction length is greatest. To confirm this process we observed the luminescence emitted by the edge of a sample excited near this edge. A temporal analysis show several short intensity spikes separated by the time light takes to make a round-trip in the sample. The spectral study revealed a dependence of the line shape with the excited zone size. The model proposed, based on a thermalyzed carrier distribution, accounts for this stimulated radiative recombination mechanism which competes with the usual mechanisms of energy relaxetion like phonon emission or spontaneous recombination
Cabrol, Olivier. "Spectroscopie et dynamique de molécules diatomiques : étude théorique des états excités du fluorure d'iode. Contribution expérimentale à la spectroscopie femtoseconde du dimère de césium." Toulouse 3, 1996. http://www.theses.fr/1996TOU30269.
Abadie, Sacha. "Vibrational excitation of molecules in the gas phase or embedded in matrices by ab initio molecular dynamics." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLE057/document.
In the thesis we have studied two prototypical systems in both condensed and gas phase,to follow and quantify the vibrational energy flow through normal modes after vibrational excitation.For the condensed phase, we considered a host Formic Acid immersedin an argon matrix, while for the gas phase we have studied the N-Methyl Acetamid... Cl.. Ar cluster. After the preparation of initial conditions using a semi-classical Wigner sampling, several DFT-MD trajectories have been performed to analyse the Intra/Inter vibrational energy relaxation. Two theoretical methods have been used to follow the evolution with time of the vibrational quantum numbers: a new method based on the study of vibrational density of states (VDOS)compared with a more traditional method based on the study of the amplitude of a specificmotion of the molecule (i.e. distance or angle). Both methods reveal similar results.In the condensed phase, the quantum yield of the trans/cis isomerisation process of theFormic Acid molecule has been compared to the experimental data. We have shown that thevibrational excitation of two combination modes involves in some cases the isomerisation ofthe Formic Acid molecule. This initial vibrational excitation of the Formic Acid has also animpact on the surrounding matrix: the energy initially contained into the FA is redistributedto the matrix leading to the deformation and the melting (solid-liquid transition) of theargon matrix.In the gas phase, we have shown that vibrational excitation of the N-H stretching motion ofthe (Cl...NMA) involves the systematic loss of the argon atom. Finally, the two models have shown that in both condensed or gas phase environment, after the vibrational excitation (n=1) of a normal modeat t=0 of the dynamics, this normal mode comes back in its ground state (n=0)
Moutard, Pascal. "Dynamique et spectroscopie d'états atomiques ou moléculaires de gaz rares, obtenus par excitation à un ou plusieurs photons, simultanés ou séquentiels." Lyon 1, 1986. http://www.theses.fr/1986LYO10089.
Moutard, Pascal. "Dynamique et spectroscopie d'états atomiques ou moléculaires de gaz rares, obtenus par excitation à un ou plusieurs photons, simultanés ou séquentiels." Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb375998980.
Taha, Abdel-Kaddous. "Etude analytique d'une équation de Duffing à double excitation périodique et détermination d'une structure caractéristique de bifurcation." Toulouse, INSA, 1989. http://www.theses.fr/1989ISAT0022.
Briend, Yvon. "Dynamique de rotors embarqués sous sollicitations multi-axiales et multi-fréquentielles : Modélisation et expérimentation." Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEI068.
The research topic of the thesis, carried out within the framework of the ANR-SME AdViTAM labcom (LaMCoS, INSA Lyon and AVNIR Engineering), addresses the dynamics of rotating machines subject to base excitations. These machines, so-called on-board rotors, play a paramount role in high-tech industrial sectors. The movements of the base are capable of triggering dynamic behaviors that can threaten the integrity of the structure. It is therefore essential to foresee the emergence of such phenomena in order to be able to avoid them or at least limit their impacts. For this, the thesis proposes the model of a shaft-disc-hydrodynamic bearing system mounted on a mobile base. This is based on a 1D finite element formulation of Timoshenko beam with six degrees of freedom. 2D finite elements are used to obtain the 2D pressure field of the hydrodynamic bearings. In addition, a kinematic model with six degrees of freedom is developed to better control the 6-axis hydraulic exciter of the Equipex PHARE and to facilitate the calculation-measurement comparison. The developed computer code is called AdViSOR. In the linear domain, the numerical analysis of parametric stability is carried out with the theory of Floquet. Stability charts are established with either single-axis stresses imposed sequentially, or multi-axial. A model reduction method is proposed to avoid prohibitive computation times of the complete model. Finally, the experimental validation of the model is carried out using an academic rotor test bench designed and called AdROK, instrumented accordingly and mounted on the 6-axis exciter. The dynamic behavior of the rotor in bending, in torsion and in axial, is then analyzed with movements of the base in translation and / or in rotation, mono- and / or multiaxial, harmonic or random or sine swept. Comparisons are made in terms of orbits, full frequency spectra, transient temporal responses and power spectral densities
Bouhafs, Nezha. "Excitation des hydrures d’azote par l’hydrogène atomique et moléculaire." Thesis, Normandie, 2017. http://www.theses.fr/2017NORMLH15/document.
Observation and study of interstellar molecular clouds require the knowledge of molecular data to derive the physical conditions (temperature, gas density, molecular abundance) of these media. Nitrogen hydrides are highly abundant species in the interstellar medium and they are found to be important reaction intermediates in the nitrogen chemistry. The interpretation of nitrogen hydrides observations from the HERSCHEL spatial observatory and the ALMA interferometer, requires accurate collisional rate coefficients of these molecules. The present thesis focuses on the determination of new rate coefficients for NH, NH2 and NH3 molecules in collision with Ne, H2 et H, respectively. Inelastic cross sections for the rotational excitation of all the studied systems have been computed with a close coupling method using the molecular dynamic codes MOLSCAT and HIBRIDON. The cross sections are then used to calculate the collisional rate coefficients for temperatures ranging from 5 to 200 K. The new rate coefficients were included in radiative transfer calculations in order to model the observed transitions of NH2 towards high-mass star-forming region W31C. We show that using the previously published rate coefficients instead of these new ones have a significant impact on the modeling, leading to important differences on the density, abundance and on the OPR of NH2. The new data will allow to put interesting constraints on the physical condition of the molecular cloud
Sobocinski, Przemyslaw. "Dynamique de la fragmentation de la molécule H2 consécutive à une capture électronique dans les collisions O5+ et Xe23+ + H2 à basse et très basse énergie." Caen, 2003. http://www.theses.fr/2003CAEN2039.
Gourc, Etienne. "Etude du contrôle passif par pompage énergétique sous sollicitation harmonique : Analyses théoriques et expérimentales." Thesis, Toulouse, INSA, 2013. http://www.theses.fr/2013ISAT0033/document.
The work presented in this thesis deal with the passive control of dynamic systems subjected to an harmonic forcing using a Nonlinear Energy Sink (NES). Several research ways have been identified : the experimental study of an harmonic oscillator with an embedded NES, the study of an alternative type of NES and an application for the passive control of chatter instability during machining operations.The theoretical analysis of an harmonically oscillator with an embedded NES with cubic stiffness coupling allow us to reveal the relaxation cycles. A design procedure is presented and applied to the realization of an experimental setup.The next section is devoted to the study of a vibro-impact NES (VI-NES). The theoretical analysis gives an insight on analog relaxation cycle similar to those observed with a NES with cubic stiffness. An experimental setup is presented and these relaxation cycles are observed.In the last section, the idea of passively controling the chatter instability during turning operation using a NES is studied. This possibility is demonstrated theoretically as well for a classic cubic NES as for a VI-NES. This passive control is performed experimentally and a reduction of the vibration amplitude is observed
Lietard, Aude. "Dynamique ultrarapide de molécules et d’agrégats excités électroniquement." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112212/document.
This PhD thesis investigated the ultrafast dynamics of photochromic molecules and argon clusters in the gas phase at the femtosecond timescale. Pump-probe experiments are performed in a set-up which associates a versatile pulsed molecular beam coupled to a photoelectron/photoion velocity map imager (VMI) and a time-of-flight mass spectrometer (TOF-MS). Theses pump-probe experiments provides the temporal evolution of the electronic distribution for each system of interest. Besides, a modelization has been performed in order to characterize the density and the velocity distribution in the pulsed beam. Regarding the photochromic dithienylethene molecules, parallel electronic relaxation pathways were observed. This contrasts with the observation of sequential relaxation processes in most molecules studied so far. In the present case, the initial wavepacket splits in two parts. One part is driven to the ground state at the femtosecond time scale through a conical intersection, and the second part remains for ps in the excited state and experiences oscillations in a suspended well. This study has shed light into the intrinsic dynamics of the molecules under study and a general relaxation mechanism has been proposed, which applies to the whole family of dithienylethene molecules whatever the state of matter (gas phase or solution) in which they have been investigated. Concerning argon clusters excited at about 14 eV, two behaviors of different time scale have been observed at different time scales. The first one occurs in the first picoseconds of the dynamics. It corresponds to the electronic relaxation of an excitonic state at a rate of 1 eV.ps⁻¹. The second phenomenon corresponds to the localization of the exciton on the excimer Ar₂*. This phenomenon is observed 4-5 ps after the excitation. In this study, we also observed the ejection of excited argon atoms, addressing the lifetime of the delocalized excitonic state. This work provide additional informations compared to those contributed in condensed phase and it pave the way for new studies in gas phase on more complex system such as nanoparicles
Plagne, Laurent. "Equation de Vlasov appliquée à la dynamique électronique des agrégats de sodium lors de collisions avec des ions." Université Joseph Fourier (Grenoble), 1998. http://www.theses.fr/1998GRE10272.
Gueu, Pascaline. "Imagerie de la dynamique de fluorescence (FLIM, FCS) par excitation à deux photons pour des études en milieu cellulaire et au sein de biofilms monobactériens." Paris 11, 2007. http://www.theses.fr/2007PA112268.
The imaging of the biphotonic fluorescence emission dynamics is a technological development especially attractive in biophotonic. In particular, the FLIM and FCS techniques make cell imaging possible with a real-time follow-up of the occurring biological phenomena. Furthermore, their combination to a multiphotonic excitation increases their performance in terms of spatial resolution, penetration depth and harmlessness to biological systems. FLIM with two-photon excitation was used for the in-vitro and ex-vivo study of the 2-styrylquinoline Fz41 VIH-1 anti-integrase. The reaction dynamic study in solution of this component enabled us to check its specific recognition of the integrase. These data were compared with measurements performed in HeLa cells transduced with a lentiviral vector. By using the fluorescence lifetime as a contrast factor, the Fz41 intracellular activity could be described. The FCS was used to study the diffusion-reaction of c2 bacteriophages in biofilms (microbial community in an organic matrix) sensitive or not to this biological entity. The experimental results enabled us to conclude that the viral particle diffusion into biofilms is controlled by the exopolymeric matrix. In this study, for the first time, with the FCS technique, it was possible to visualise in situ the interaction of bacterophages with the bacteria whose membrane contained the specific recognition site
Saad, Rawad. "Etudes physico-chimiques des plasmas induits par laser pour l'analyse quantitative des matériaux dans les systèmes nucléaires." Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0172/document.
Laser Induced Breakdown Spectroscopy (LIBS) is a multi-elemental analysistechnique very well suited for analysis in hostile environments particularly in thenuclear industry. Quantitative measurements are frequently performed on liquid orsolid samples but in some cases, atypical signal behaviors were observed in theLIBS experiment. To avoid or minimize any impact on measurement accuracy, it isnecessary to improve the understanding of these phenomena. In the framework of athree-year PhD thesis, the objective was to study the chemical reactions occurringwithin laser-generated plasma in a LIBS analysis. Experiments on a model material (pure aluminum sample) highlighted thedynamics of molecular recombination according to different ambient gas. Thetemporal evolution of Al I atomic emission lines and molecular bands of AlO and AlNwere studied. A collisional excitation effect was identified for a peculiar electronicenergy level of aluminum in the case of a nitrogen atmosphere. This effectdisappeared in air. The aluminum plasma was also imaged during its expansionunder the different atmospheres in order to localize the areas in which the molecularrecombination process takes place. Spectacular particle projections have beenhighlighted
Uranga-Piña, Llinersy. "Ultrafast geometrical rearrangement of solid neon upon photoexcitation of a NO impurity : a quantum dynamics study." Toulouse 3, 2012. http://thesesups.ups-tlse.fr/1904/L.
This thesis reports on results of quantum molecular dynamics simulations of photo-induced structural dynamics in nitric oxide (NO) doped solid neon (Ne). The local perturbation, caused by the optical excitation of the dopant molecule, propagates radially from the NO to the lattice atoms, in a shock-wave-like fashion. The ultrafast relaxation dynamics is studied using a purely quantum mechanical approach, based on a multidimensional shell model, with the shell radii being the dynamical variables. As a consequence of the weak anisotropy of the NO-Ne interaction, the model accounts for the main dynamical features of the rare gas solid while it implies a significant dimensionality reduction with respect to the real condensed phase system. The numerical propagation of the multidimensional wave packet allows the analysis of both the static deformation of the solid due to the impurity and the dynamical response after femtosecond excitation. The photo-induced dynamics of solvent atoms around the impurity centre is found to be a complex collective process, which involves many degrees of freedom. The proposed theoretical methodology allows to consider realistic time-dependent femtosecond pulses and the effect of the pulse duration on the geometrical rearrangement dynamics is clearly shown. The time-resolved absorption spectra were simulated, using the pulse parameters of previous pump-probe spectroscopic experiments, carried out with with femtosecond time-resolution. The computed transient signals qualitatively reproduce the experimental results, thereby enabling a clear analysis of the ultrafast mechanism of the energy transfer into the solid. The influence of explicitly including dynamical correlations in the theoretical treatment of the relaxation dynamics, within the Multi-Configurational Time-Dependent Hartree (MCTDH) scheme, was addressed. This aspect is found to be important only for certain degrees of freedom. The consideration of multi-configurational wave functions does not appreciably modify the values of observables such as the average shell radii, with respect to those obtained employing the time-dependent Hartree ansatz. However, the inclusion of correlations reduces the degree of structuring of the calculated pump-probe signals and improve the agreement with experimental results
Mouret, Liza. "Dynamique quantique par une méthode de paquets d'ondes. Etude des collisions électron-hydrogène et atome-dihydrogène." Phd thesis, Université Rennes 1, 2002. http://tel.archives-ouvertes.fr/tel-00002842.
Rogemond, François. "Propriétés de fluorescence de monocristaux de Bi Ge O (B.G.O.) sous excitation laser dynamique des états excités et effets de saturation, analyse de la structure électronique des centres luminogènes /." Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb376007458.
Rogemond, François. "Propriétés de fluorescence de monocristaux de Bi4 Ge3 O12 (B. G. O. ) sous excitation laser : dynamique des états excités et effets de saturation : analyse de la structure électronique des centres luminogènes." Lyon 1, 1986. http://www.theses.fr/1986LYO10021.
Boyé-Péronne, Séverine. "Etude expérimentale de la structure et de la dynamique des états de Rydberg de la molécule d'acétylène par excitation laser multiphotonique et rayonnement synchrotron : approche théorique de l'isomère vinylidène, application astrophysique." Paris 11, 2001. http://www.theses.fr/2001PA112259.
The acetylene molecule (C2H2) is an abundant species in circumstellar envelopes and cometary atmospheres, and plays a crucial role in interstellar carbon chemistry. This Thesis consists of an experimental investigation of the relaxation mechanisms in the Rydberg states of C2H2. These excited states dominate the VUV absorption spectrum of acetylene, and are known to be predissociated to some degree. They may therefore be considered as doorway states towards fragmentation processes. The initial goal of this work was to complete the spectroscopy of C2H2 Rydberg states, using the technique of Resonant Multiphoton Ionization with pulsed nanosecond lasers. Subsequently, the dissociative relaxation pathways were probed through selectively excited Rydberg states in experiments carried out in the Synchrotron Radiation Facility in Orsay (Super-ACO). The visible fluorescence emission of the carbonated fragments C2H, CH and C2 have been analyzed as a function of the excitation energy utilizing an original optical system, designed to optimize the visible fluorescence collection. The main body of results deal with the characterization of a unique dissociative channel C2H2 + hv --> C2H + H below the first ionization potential (IP). Above the IP, many other channels are open, such as concerted fragmentation combined with molecular H2 elimination. The evolution of the C2H radical quasi-continuous emission (range 400-850 nm) has been explained by the production of C2H in highly excited bending levels of the A state, in the region of the isomerisation barrier. Finally, a theoretical characterization has been performed of the vinylidene isomer H2CC of acetylene, in order to better understand the isomerisation channel. Via quantum chemistry ab initio calculations, the structure and nature (valence or Rydberg) of the first 12 excited singlet states of vinylidene have been determined for the first time, up to 10eV above the ground state
Lattouf, Elie. "Etude expérimentale de la formation de l’ion d’hydrogène négatif lors de collisions entre un ion positif et une cible atomique ou moléculaire." Caen, 2013. http://www.theses.fr/2013CAEN2075.
The formation of the negative hydrogen ion (H–) in collisions between a positive ion and a neutral atomic or molecular target is studied experimentally at impact energies of a few keV. The doubly-differential cross sections for H– formation are measured as a function of the kinetic energy and emission angle for the collision systems OH+ + Ar and O+ + H2O at 412 eV/a. M. U. These H– ions can be emitted at high energies (keV) in hard quasi-elastic two-body collisions involving a large momentum transfer to the H center. However, H– anions are preferentially emitted at low energy (eV) due to soft many-body (> 2) collisions resulting in a low momentum transfer. The formation of H– ions by electron capture follows excitation or ionization of the molecule. The molecular fragmentation dynamics is modeled to simulate the emission of H– ions. The overall good agreement between the simulation and the experiment leads to the understanding of most of the experimental observations
Mendoume, Minko Ignace Davy. "Identification des systèmes dynamiques stochastiques." Phd thesis, Clermont-Ferrand 2, 2005. https://tel.archives-ouvertes.fr/tel-00676619/document.
Taoutioui, Abdelmalek. "Étude théorique de la dynamique électronique au cours de collisions entre des ions et des cibles atomiques hautement excitées." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS323.
The understanding of the electronic processes taking place during atomic collisions is of great interest for the modeling of phenomena observed in complex systems such as atmospheric, astrophysical and biological environments. These processes manifest at the microscopic level but play a determining role on the evolution and the physicochemical properties of these macroscopic systems. From a fundamental point of view, collisions are also privileged "laboratories" for the study of quantum systems with N-bodies. Ion-atom collisions are of crucial importance in several fields such as that concerning nuclear fusion by magnetic confinement: the understanding of the electronic processes is necessary for the modeling of this type of plasmas. This thesis is situated in this context and is dedicated to the theoretical study of the electronic processes that occur during collisions between ions and highly excited atomic targets. In this work, we privileged the modeling of the electronic capture and the computation of the cross sections for the proton-hydrogen system. We adopted two non-perturbative theoretical approaches: the classical CTMC method and a semi-classical SCAOCC method. We calculated the total and partial capture cross sections for targets initially excited up to the n = 7 layer. Comparisons between the results of these methods and the few theoretical data available are made and represent the originality of the work. Empirical scale laws for total cross sections are also described
Oddos-Marcel, Lionel. "Etude des états électroniques et de la dynamique de relaxation d'un dimère de phtalocyanine de silicium." Université Joseph Fourier (Grenoble), 1998. http://www.theses.fr/1998GRE10121.
Desclaux, Anthony. "Etude expérimentale du comportement linéaire et non linéaire d’une flamme diphasique soumise à une excitation acoustique. Mise en œuvre d’une méthode de contrôle adaptative." Thesis, Toulouse, ISAE, 2020. http://depozit.isae.fr/theses/2020/2020_Desclaux_Anthony_D.pdf.
This PhD thesis supports the effort undertaken by ONERA to understand the mechanisms of stabilizationof two-phase flames in aeronautical engines. This work concerns more particularly the dynamics of spraysand flames disturbed by acoustic waves. This work studies the role of liquid fuel injection on the non-linearresponse of stabilized flames downstream of an industrial multipoint injector with a central pilot zone. Basedon previous work, the first objective is to study the influence of acoustic disturbances on the behavior ofliquid fuel injection in the multipoint zone. The observed phenomena are reproduced, in an idealized form,from a simplified experimental set up based on the configuration of a liquid jet injected into air crossflowsubmitted to an acoustic forcing. The results highlight the atomization mechanisms of the jet and itsinteraction with acoustic disturbances. The study of the spray shows the appearance of droplet densitywaves. The influence of drop size on these phenomena is characterized. The second objective of this workis to analyze the behavior of a two-phase flame (kerosene/air) disturbed by acoustic excitations. In this case,a second experimental configuration is implemented. This experimental set up reproduces in a realistic waythe phenomena encountered in combustion chambers. This work uses the "Flame Describing Function"(FDF) approach. In order to do this, the fluctuations of the heat release rate from the flame are characterizedusing an original method based on the simultaneous measurement of the chemiluminescence of severalradicals. The results are obtained for two injection configurations, one using the pilot zone alone and theother using the entire injector. The analysis of the FDFs reveals saturation phenomena which limit the flameresponse. Comparison of the results between the two injection configurations shows that the delay betweenflame response and flow disturbances is strongly influenced by the injection mode. All the results obtainedin this work constitute an experimental database to validate reactive LES simulations and to provide a modelfor describing the flame behavior in simulations based on "low order" approaches
Yuma, Bertrand Kei. "Etude de la dynamique des états excités des nanotubes du carbone mono-paroi." Phd thesis, Université de Strasbourg, 2013. http://tel.archives-ouvertes.fr/tel-00994244.
Allani, Anissa. "Conception et optimisation d'amortisseurs à masse accordée pour les structures du génie civil." Thesis, Paris Est, 2015. http://www.theses.fr/2015PESC1137/document.
The architectural demand and the desire to reduce costs permit the construction of light structures with innovating shapes. The great flexibility of these structures makes them increasingly sensitive to the external dynamic loads such as traffic, wind and earthquakes. Vibration control techniques allow to construct modern buildings increasingly slender, and, whether they are economic or architecturally audacious. Instead of modifying the geometrical and mechanical characteristics of a structure, vibration control consists in producing reaction forces which are opposed to the negative effects of the external excitations when they appear. This technological advance has the great advantage to not influencing planners and architects’ work and it provides them with additional creative options in both geometrical and mechanical characteristics of buildings. We restrict our focus to passive vibration control. Among available passive vibration absorber systems, Tuned Mass Dampers (TMDs) were selected for their simplicity and reliability. A TMD consists of a mass, a dashpot, and a spring, and is commonly attached to a vibrating primary system to suppress undesirable vibrations. The performance of TMDs is strongly affected by the adjustment of their parameters. The problem is the optimization of the mechanical parameters of TMD and their location in order to attenuate vibrations of the main structure. This thesis is based on understanding the dynamic characteristics of TMD. It aims to make an innovative and original contribution to classify, generalize and optimize some criteria in order to ensure an optimal design of TMDs, depending on their application. Our work consisted to treat these criteria in an original way. After solving the direct problem based on the modelling of systems with one or several TMD, we tackled the indirect problem by considering various optimization criteria. Thus, several optimization criteria of the mechanical parameters of TMDs applied to a main system (single (SDOF) or multiple degrees of freedom (MDOF)) are used. The excitation of the main system can be done in two different ways; either on the base (for seismic application) or on the structure (for wind effects).Numerical simulations based on a time and frequency approach are used to examine the performance of each optimized model. The robustness of each optimization criterion is assessed by taken into account the uncertainties related to the change of the physical parameters of the main structure. Such problems can be discussed by considering sensitivity analysis for criteria under uncertainty of the optimum TMD parameters. A new and original contribution of this thesis is the design and optimization of multiple TMDs in parallel with a MDOF main structure. In this context, during seismic loads, modes in the main structure with relatively high effective masses can be readily excited by base excitation. Afterwards, optimization criterion can be developed based on the most sensitive storeys to vibration modes which are a cumulative modal effective mass fraction exceeding 90%. To protect structures under earthquake loads, we seek to assess the effectiveness of TMDs in mitigating the response of structure under different real earthquakes. A comparative study is then achieved with four real earthquakes applied on systems with TMD optimized parameters. To illustrate the results obtained, characterization tests are conducted on a TMD with damping by eddy currents effect and adjustable stiffness. They allow the validation of the model and optimization criterion adopted
Zhang, Zailan. "Electronic structures, quasi-particle and gap dynamics in copper oxides superconductors using Time and Angle Resolved Photoemission Spectroscopy." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066126/document.
The superconductors of the copper-oxide family have been matter of extensive investigations and are still subject of fierce debates. After 30 years of research, some issues have been settled, whereas others remain controversial. The evolution of the superconducting order parameter with temperature and doping level is an exemplary case. In this thesis, we report a systematic Time resolved Angle Resolved PhotoEmission Spectroscopy (ARPES) study of the optimally doped Bi2Sr2CaCu2O8+δ to explore the possibility that an intense photoexcitation of the superconductor can generate a state with incoherent copper pairs and no superfluid density. The employed experimental methods allow us to measure the dynamics of non-equilibrium electrons and of the superconducting gap, providing complementary information to conventional ARPES and optical measurement. Our time resolved ARPES data of Bi2Sr2CaCu2O8+δ, report a momentum-dependent collapse of the superconducting gap upon photoexcitation. Interestingly, the QP relaxation develops a faster component at the threshold fluence F_pair where the gap has fully collapsed. The comparison between the F_pair and the F_phase extracted by tr-THz suggested the existence a fluence regime when the Cooper pairs have survived, but without holding superfluid current. A second major challenge in the physics of HTSCs is the poor understanding of the normal phase at high temperature. We also present the ARPES study of the near nodal pseudo-gap in La2-xBaxCuO4 (LBCO) to show a possible link with charge modulation (stripes). Our data show that the near nodal gap open below the LTT-LTO transition, which is linked to the formation of such modulations, instead of the one where spin modulations appear. The data show that the band structure of LBCO is affected by a renormalization setting in prior to the 70 meV kink. We were able to correlate this renormalization of the ARPES data to the region where the Cu-O bond-stretching mode soften, both in energy and momentum space
Li, Li. "Etude et mise au point d'une nouvelle famille d'alterno-démarreur pour véhicules hybrides et électriques." Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00639305.
Zhang, Zailan. "Electronic structures, quasi-particle and gap dynamics in copper oxides superconductors using Time and Angle Resolved Photoemission Spectroscopy." Electronic Thesis or Diss., Paris 6, 2017. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2017PA066126.pdf.
The superconductors of the copper-oxide family have been matter of extensive investigations and are still subject of fierce debates. After 30 years of research, some issues have been settled, whereas others remain controversial. The evolution of the superconducting order parameter with temperature and doping level is an exemplary case. In this thesis, we report a systematic Time resolved Angle Resolved PhotoEmission Spectroscopy (ARPES) study of the optimally doped Bi2Sr2CaCu2O8+δ to explore the possibility that an intense photoexcitation of the superconductor can generate a state with incoherent copper pairs and no superfluid density. The employed experimental methods allow us to measure the dynamics of non-equilibrium electrons and of the superconducting gap, providing complementary information to conventional ARPES and optical measurement. Our time resolved ARPES data of Bi2Sr2CaCu2O8+δ, report a momentum-dependent collapse of the superconducting gap upon photoexcitation. Interestingly, the QP relaxation develops a faster component at the threshold fluence F_pair where the gap has fully collapsed. The comparison between the F_pair and the F_phase extracted by tr-THz suggested the existence a fluence regime when the Cooper pairs have survived, but without holding superfluid current. A second major challenge in the physics of HTSCs is the poor understanding of the normal phase at high temperature. We also present the ARPES study of the near nodal pseudo-gap in La2-xBaxCuO4 (LBCO) to show a possible link with charge modulation (stripes). Our data show that the near nodal gap open below the LTT-LTO transition, which is linked to the formation of such modulations, instead of the one where spin modulations appear. The data show that the band structure of LBCO is affected by a renormalization setting in prior to the 70 meV kink. We were able to correlate this renormalization of the ARPES data to the region where the Cu-O bond-stretching mode soften, both in energy and momentum space
Maliyov, Ivan. "Irradiation ionique des matériaux : dynamique des excitations électroniques en temps réel." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS434.
Ionic irradiation damage in condensed matter is central to many technological applications: materials in nuclear plants of course, but also electronics and solar panels in space that are subjected to the cosmic irradiation, living matter treated by radiotherapy to eliminate tumors, etc. For all these subjects, an accurate knowledge of the interaction between the irradiating projectile and the target is crucial. The interaction between the irradiating ion and the target material can be described by a stopping power, defined as the energy transfer from projectile to material per penetration distance. The most important ionic energy loss channels in the irradiation process are the electronic excitations. Therefore, the electronic stopping power is the central quantity in this field. With the advent of time-dependent density-functional theory (TDDFT), it is nowadays possible to provide a complete and realistic quantum-mechanical description of the phenomenon.In this thesis, we have developed a fully ab initio real-time TDDFT (RT-TDDFT) approach in the localized Gaussian basis. This implementation has several appealing advantages, such as the cheap account of core electrons, the ease of using the modern hybrid functionals, the flexibility of the basis set and overall low computational cost. With our tool, we explored the bulk limit, the validity of the projectile impact parameter averaging to obtain the experimental random electronic stopping power. We have proven the importance of core electron excitations in the ionic irradiations. A great care wasalso taken about the Gaussian basis set convergence: the extrapolation of the stopping power based on standard basis sets and the basis set generation scheme were proposed.Finally, we have computed the random electronic stopping power in lithium and aluminum targets for three types of projectiles: protons, antiprotons, and alpha-particles. We have compared our results directly to the experiment as well as to the empirical code SRIM, which is a widely-used database of stopping powers and a de facto standard for experimentalists. The agreement with SRIM is good when the SRIM database contains enough experimental points, whereas we show that the SRIM extrapolation can be hazardous when the underlying experimental data points are too few. Concerning the antiproton irradiation, our RT-TDDFT calculations show that the antiproton stopping power is lower than the proton one, which is in agreement with the general experimental observation (the so-called Barks effect). This effect is out of reach of simpler theories, such as the linear response approximation
Galparsoro, Larraza Oihana. "Phonon and electron excitations in diatom abstraction from metallic surfaces." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0417/document.
The rationalization of elementary processes at surfaces is of prime importance for numerous natural and technological areas. From a fundamental pointof view, the way the energy concomitant to any chemical reaction is distributed among the desorbing molecules degrees-of-freedom and the surface is far frombeing fully pictured. In this work, quasiclassical molecular dynamics (QCT)simulations have been carried out to investigate this issue for the recombination ofH2 and N2 resulting from atomic adsorbate abstraction by atom scattering off theW(100) and W(110) covered surfaces, these processes being of relevance inplasma-wall interactions. Potential energy surfaces, built from density functional(DFT) theory calculations, have been used to simulate, within the framework ofclassical dynamics (including semi-classical corrections), the subpicosecond Eley-Rideal and Hot-Atom processes. The implementation of effective models to accountfor energy dissipation to surface phonons and electron-hole pair excitations, have allowed to rationalize the non-adidabatic dynamics of atom abstraction at metalsurfaces
Lopez, Cédric. "Méthodes d'optimisation des trains d'atterrissage d'hélicoptère." Phd thesis, Paris, ENSAM, 2007. http://pastel.archives-ouvertes.fr/pastel-00003600.