Academic literature on the topic 'Force de polarisation adaptative'
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Journal articles on the topic "Force de polarisation adaptative"
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Tommasini, Matteo, Daniele Fazzi, Alberto Milani, Mirella Del Zoppo, Chiara Castiglioni, and Giuseppe Zerbi. "Intramolecular Vibrational Force Fields for Linear Carbon Chains through an Adaptative Linear Scaling Scheme." Journal of Physical Chemistry A 111, no. 45 (2007): 11645–51. http://dx.doi.org/10.1021/jp0757006.
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Jenkins, Kelsey M., and Jack O. Shaw. "Bite force data suggests relationship between acrodont tooth implantation and strong bite force." PeerJ 8 (June 30, 2020): e9468. http://dx.doi.org/10.7717/peerj.9468.
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Extant and extinct reptiles exhibit numerous combinations of tooth implantation and attachment. Tooth implantation ranges from those possessing roots and lying within a socket (thecodonty), to teeth lying against the lingual wall of the jawbone (pleurodonty), to teeth without roots or sockets that are attached to the apex of the marginal jawbones (acrodonty). Attachment may be ligamentous (gomphosis) or via fusion (ankylosis). Generally speaking, adaptative reasonings are proposed as an underlying driver for evolutionary changes in some forms of tooth implantation and attachment. However, a substantiated adaptive hypothesis is lacking for the state of acrodont ankylosis that is seen in several lineages of Lepidosauria, a clade that is plesiomorphically pleurodont. The convergent evolution of acrodont ankylosis in several clades of lepidosaurs suggests a selective pressure shaped the evolution of the trait. We hypothesize that acrodont ankylosis as seen in Acrodonta and Sphenodon punctatus, is an adaptation either resulting from or allowing for a stronger bite force. We analyzed bite force data gathered from the literature to show that those taxa possessing acrodont dentition possess a stronger bite force on average than those taxa with pleurodont dentition. Dietary specialists with pleurodont dentition may also possess relatively high bite forces, though body size may also play a role in their ability to bite hard. Furthermore, our results have implications for the evolution of acrodont ankylosis and potential behaviors related to strong bite force that influenced the evolution of acrodonty within Acrodonta and Rhynchocephalia.
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Peugny, Camille. "The decline in middle-skilled employment in 12 European countries: New evidence for job polarisation." Research & Politics 6, no. 1 (2019): 205316801882313. http://dx.doi.org/10.1177/2053168018823131.
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Is the middle class shrinking? This article contributes to the debate on job polarisation in Europe. Based on data from the European Union Labour Force Survey (EU-LFS) and looking at 12 European countries, it shows that there is an evident trend towards job polarisation. While this polarisation takes various forms, it is clearly the highest- and lowest-skilled jobs that have increased most rapidly among the active population over the past 20 years, to the detriment of middle-skilled jobs. The article then goes on to demonstrate that polarisation also exists when it comes to working conditions insofar as the lowest-skilled jobs are also where the most precarious employment conditions are found. Conversely, the remaining middle-skilled jobs are relatively shielded from this decline in working conditions.
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Villeneuve, Paul. "Les rapports femmes-hommes en milieu urbain: patriarcat ou partenariat ?" Cahiers de géographie du Québec 35, no. 95 (2005): 385–401. http://dx.doi.org/10.7202/022184ar.
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The paper first shows, in the context of recent theorising on hierarchies and markets, the existence of relationships between increasing female labour force participation and the emergence of certain forms of urban social polarisation. These new forms of polarisation are then linked with occupational asymmetry within employed couples. This analysis tends to suggest that central city neighbourhoods are milieux more conducive to the erosion of patriarchy than suburbs. Finally, the question of a new gender partnership is suggested to be as crucial to the theorising on local development than that of class partnership.
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Murphy, Emily C., and Daniel Oesch. "Is Employment Polarisation Inevitable? Occupational Change in Ireland and Switzerland, 1970–2010." Work, Employment and Society 32, no. 6 (2017): 1099–117. http://dx.doi.org/10.1177/0950017017738944.
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The routinisation thesis expects technology to hollow out the middle of the employment structure, leading to a uniform pattern of polarisation across affluent countries. This article argues that occupational change is also shaped by labour supply – particularly education and immigration – and institutions. Polarisation therefore represents just one scenario of occupational change. Our study of Ireland and Switzerland examines long-term change in the employment structure (1970–2010), using census data and an encompassing definition of the labour force. Results show no simple trend of occupational upgrading morphing into polarisation. Occupational upgrading occurred in both countries, with the largest employment gains in high-paid occupations and the largest losses in low-paid ones. Patterns of occupational change largely aligned with the evolution of labour supply, upgrading in the 1990s and 2000s being driven in both countries by higher educated women. Immigration supplied labour for low-end and mid-level jobs in Ireland during the Celtic Tiger era, and for low-paid occupations in Switzerland during the 1980s.
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Dong, Yan, Xiaodong Dai, Lianyu Zhao, Li Gao, Zongli Xie, and Jianhua Zhang. "Review of Transport Phenomena and Popular Modelling Approaches in Membrane Distillation." Membranes 11, no. 2 (2021): 122. http://dx.doi.org/10.3390/membranes11020122.
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In this paper, the transport phenomena in four common membrane distillation (MD) configurations and three popular modelling approaches are introduced. The mechanism of heat transfer on the feed side of all configurations are the same but are distinctive from each other from the membrane interface to the bulk permeate in each configuration. Based on the features of MD configurations, the mechanisms of mass and heat transfers for four configurations are reviewed together from the bulk feed to the membrane interface on the permeate but reviewed separately from the interface to the bulk permeate. Since the temperature polarisation coefficient cannot be used to quantify the driving force polarisation in Sweeping Gas MD and Vacuum MD, the rate of driving force polarisation is proposed in this paper. The three popular modelling approaches introduced are modelling by conventional methods, computational fluid dynamics (CFD) and response surface methodology (RSM), which are based on classic transport mechanism, computer science and mathematical statistics, respectively. The default assumptions, area for applications, advantages and disadvantages of those modelling approaches are summarised. Assessment and comparison were also conducted based on the review. Since there are only a couple of full-scale plants operating worldwide, the modelling of operational cost of MD was only briefly reviewed. Gaps and future studies were also proposed based on the current research trends, such as the emergence of new membranes, which possess the characteristics of selectivity, anti-wetting, multilayer and incorporation of inorganic particles.
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Goldyn, A. M., B. A. Rioja, J. P. Spatz, C. Ballestrem, and R. Kemkemer. "Force-induced cell polarisation is linked to RhoA-driven microtubule-independent focal-adhesion sliding." Journal of Cell Science 122, no. 20 (2009): 3644–51. http://dx.doi.org/10.1242/jcs.054866.
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M., Serra Pol, Pons Hernández A., Barea Vega E., and Gómez Luque M. "Do adaptative changes occur in the achilles tendons of endurance runners?" Revista Fisioterapia Invasiva / Journal of Invasive Techniques in Physical Therapy 02, no. 02 (2019): 083. http://dx.doi.org/10.1055/s-0039-3401865.
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Abstract Introduction and Aim Several studies associate tendinopathies with structural changes in the Achilles tendon (AT). However, few studies have demonstrated whether long distance running training can generate structural changes at the level of the AT. The aim of this study was to determine whether adaptive changes exist, both structural and functional, in the AT of asymptomatic endurance runners with no history of lesions to the AT. Material and Methods A cross-sectional descriptive study. In total, 14 subjects were selected and divided into two groups of 7 subjects each. The intervention group (IG) comprised all usual runners, running over 60 km per week, with no previous lesion to the AT. The control group (CG) included all active subjects but who did not perform competitive sports nor did they run more than 10 km per week. The ankle dorsal flexion (ADF) of each subject was measured together with the index of reactive force (IRF), and the width of the AT body was measured using ultrasound, together with the level of hypervascularization, the presence of hypoechoic areas and the presence of hyperechoic areas. To measure ADF, the validated measurement was used with the application (App) Dorsiflex for IPhone. To calculate IRF, the validated measure of the Drop Jump, test from the App My Jump 2 was used. The ultrasound assessment was always performed by the same examiner. The ultrasound machine was a General Electric, Logiq V2 model for measuring both feet: the width of the AT body, the degree of hyper vascularization, the presence of hypoechoic areas and the presence of calcifications. The subject was placed in prone, with the foot hanging off the table and the ankle was in 90° flexion. The examiner was placed on the same side as the lower limb examined. Results The means of the results obtained and p-values of significance were as follows: ADF = 46° CG 43.6° IG (p > 0.005). IRF = 0.92 CG 1.07 IG (p > 0.005) Ultrasound = CG 43% presence of vascularization outside the tendon; IG 83% presence of vascularization outside the tendon. Conclusions No significant evidence exists to support that the AT in endurance runners without a history of injuries, presents functional adaptations. However, it seems that in endurance runners, there is a greater presence of vessels in Kager's fat pad, although it is necessary to obtain data from a larger population to confirm and establish the possible relationships of these changes.
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Vladisavljevic, Nebojsa, and Katrin Voltmer. "Media framing of democratisation conflicts in Egypt, Kenya, Serbia and South Africa." Sociologija 59, no. 4 (2017): 518–37. http://dx.doi.org/10.2298/soc1704518v.
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This paper presents an overview of the main findings from a quantitative content analysis covering different types of democratisation conflicts (i.e., conflicts over citizenship, elections, transitional justice and distribution of power) in Egypt, Kenya, Serbia and South Africa. The key findings from the content analysis are organised around several themes: causes of democratisation conflicts, portrayal of conflict parties, preferred solutions to conflicts, perceptions of democracy, role of the media, authoritarian past, and tone of reporting and polarisation. The main finding is that cross-national variations depend on several factors: specific country contexts (and contexts of broader regions from which they come from, including the Arab Middle East, sub-Saharan Africa and post-communist Europe); regime type and the stage of democratisation; and type of democratisation conflict (which reflects the main arenas of political contestation). Across all countries, the quality of media coverage is limited by bias, emotionalisation and - most importantly - polarisation. In particular, conflicts over the distribution of power trigger sharp polarisation, whereas elections - contrary to existing literature - seem to force media towards a more restrained style of reporting. The sample involves 5162 newspaper articles and news stories from the four countries.
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Colla, E. L., A. Raake, D. V. Taylor, and N. Setter. "Exploring polarisation switching and imprint in fatigued Pt-PZT-Pt FECAPs by atomic force microscopy." Integrated Ferroelectrics 27, no. 1-4 (1999): 171–78. http://dx.doi.org/10.1080/10584589908228466.
Full textDissertations / Theses on the topic "Force de polarisation adaptative"
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Deknuydt, Florence. "L'il-17 : polarisation innée et adaptative." Nantes, 2011. http://archive.bu.univ-nantes.fr/pollux/show.action?id=0a95bdaa-9fdf-4d66-bc51-42db3353fd4d.
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Ma thèse a porté sur la caractérisation des origines de cellules pouvant produire de l'IL-17 et appelées les Th17. Ces cellules semblent être impliquées aussi bien dans les maladies auto-immunes que dans certaines infections bactériennes. Dans ces différentes pathologies, deux types cellulaires connus comme cellules immunitaires non conventionnelles : les Tregs et les cellules T γδ jouent un rôle primordial. Les premières données obtenues chez la souris suggéraient que ces deux sous populations étaient capables de produire de l'IL-17. J'ai donc employé plusieurs techniques afin de caractériser les cellules immunitaires humaines capables de produire de l'IL-17 et les conditions nécessaires à cette production. Premièrement, j'ai réalisé un travail sur les cellules du sang périphérique en conditions non infectées. Ces travaux m'ont permis de démontrer la capacité des cellules Tregs et particulièrement des cellules MTregs à se polariser en Th17. J'ai mis en évidence que la présence d'IL-1, d'IL-2 et d'un signal TCR permet au MTreg de se polariser en cellules Th17 et que celles-ci perdent leur capacité suppressive ainsi que l'expression de Foxp3. Dans un deuxième temps, je me suis intéressée à cette cytokine dans un contexte pathologique : la Tuberculose. Pour réaliser ce projet, j'ai utilisé un modèle de formation de granulome humain in vitro mis au point par F. Altare et son équipe. J'ai ainsi pu mettre en évidence la présence d 'IL-17 au sein du granulome mycobactérien aussi bien in vitro que sur des coupes histologiques issues de biopsies de patients. De plus, la population la plus apte à se polariser en cellules productrices d'IL-17 au sein du granulome est la population LT γδ. Chez l'homme, il existe deux sous populations de LT γδ : Vδ2- ou Vδ2. Seule la sous population de δ2- semble être capable de produire de l'IL-17 dans le contexte du granulome mycobactérien humain. J'ai aussi pu mettre en évidence que cette production d'IL-17 survient tardivement, dans les stades avancés de granulomes. Enfin il semble exister un lien entre la présence d"IL-17, des cellules δ1 et de la nécrose, puisque ces cellules sont retrouvées uniquement sur les coupes de patients à lésions nécrotiques et que ceci est associé à la présence d'IL-17 au sein de ces mêmes biopsies<br>During my PhD, I characterized the cells producing the pro-inflammatory cytokine: IL-17. These cells seem to be implicated in autoimmune diseases and some bacterial infections. In these pathologies, the immune system plays an important role and particularly two cell subsets: Treg and γδ T cells. During a first period, I investigated these cells in uninfected PBMCs. During this work I demonstrated the capacity of Treg to polarise into Th17. I also demonstrated that Treg could produce IL-17 when they are activated via the TCR combined with IL-1 and IL-2. Moreover when these cells produce IL-17 they loose the expression of Foxp3 and their suppressive capacity. During a second period, I studied this cytokine in a pathologic context: human tuberculosis. To develop this project, I used an in vitro granuloma model developed by F. Altare’s team. During this work, I demonstrated the presence of IL-17 within characteristic structure of human tuberculosis: the granuloma. This cytokine is present in vitro and in sample biopsies of human granuloma. Moreover, within granuloma, γδ T cells have the best capacity to polarise. In Humans, the γδ T cells are composed of two subset: δ1 and δ2. The δ2 cells are mainly found within epithelia, whereas δ1 are mainly circulating. During my study, I could demonstrate that δ1 cells are the only cells to be able to produce IL-17 within human granulomas. This production is only displayed in late stage of granuloma. A relationship seems to exist between IL-17, δ1 and the necrosis present in the middle of granuloma, because these cells are present only in necrotic biopsies thus strongly suggesting a direct role of δ1-induced IL-17 in necrosis induction
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O'Neill, Jason Darren. "Brute force polarisation of xenon-129." Thesis, University of Nottingham, 2008. http://eprints.nottingham.ac.uk/13887/.
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In recent years the number of applications using NMR spectroscopy of hyperpolarised noble gases has expanded rapidly. The signal enhancement hyperpolarisation provides has led to its implementation in studies as diverse as materials science and biological imaging. 129Xe in particular, with its easily deformed electron cloud, is proving to be a uniquely sensitive probe for nanoporous structures. At present hyperpolarises gas production is limited to optical pumping (SEOP). In this study we investigate another approach, the brute force technique. At very low temperatures and high magnetic fields the Boltzmann distribution of spins for magnetic nuclei is heavily biased in a single direction. At temperatures below 10 mK and in magnetic fields of 15 T, 129Xe polarisations exceeding 40% are attainable. The utilisation of the brute force technique is hindered by the extraordinarily long relaxation time need for this polarisation to occur. In this study, we give details of our investigations of two relaxation catalysts, oxygen and helium-3. It is shown that paramagnetic molecular oxygen causes rapid relaxation of solid xenon at temperatures as low as 500 mK. We report on the enhanced relaxation, by liquid 3He of xenon films adsorbed on to silica gel and exfoliated graphite substrates. The investigation of this mechanism is extended to other magnetic nuclei and improved rates of relaxation are observed in 13C and 1 H. Details are also given, of how this mechanism of relaxation can be halted by the addition of superfluid 4He. Unique observations in the 129Xe NMR spectra are reported, providing a unique opportunity to study the coupling between individual layers of 129Xe atoms. Finally, a novel mechanism of cooling, by the filtering of energetic atoms through a porous ceramic membrane, is investigated.
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Vannier, Nicolas. "Imagerie polarimétrique active adaptative infrarouge pour des applications de détection et de décamouflage." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLO008/document.
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Nous avons développé et construit un imageur polarimétrique actif avec une illumination laser à la longueurd'onde 1:55 um. Il peut générer et analyser tous les états de polarisation de la sphère de Poincaré. Il permetde réaliser une optimisation polarimétrique du contraste en analysant la scène à l'aide d'un algorithme desegmentation ultra rapide basé sur des contours actifs. Cet imageur nous permet de comparer plusieursmodalités d'imagerie possédant des nombres de degrés de liberté polarimétrique différents. Nous effectuons ladétection d'objets manufacturés dans différents environnements avec l'imagerie polarimétrique active pourillustrer les capacités de ces modalités. Nous démontrons l'effcacité de l'imagerie polarimétrique active pourdes applications de décamouffage et de détection d'objets dangereux, et mettons en évidence lescaractéristiques qu'un imageur polarimétrique doit posséder pour ce type d'applications. Nous montrons quedans la majorité des scénarios étudiés, les matrices de Mueller sont presque diagonales, et que desperformances de détection satisfaisante peuvent être atteintes avec des imageurs polarimétriques plus simplesqui ont un nombre de degrés de liberté réduit. De plus, la normalisation de l'intensité des images est unecondition nécessaire pour mieux révéler le contraste polarimétrique<br>We designed and built an active polarimetric imager with laser illumination at 1:55 um wavelength. It cangenerate and analyze any polarization state on the Poincaré sphere. It let us the possibility to perform apolarimetric contrast optimization by analyzing the scene with an ultrafast active-contour-based segmentationalgorithm. This imagins systeme allow to compare several imaging modes having different numbers ofpolarimetric degrees of freedom. We address the detection of manufactured objects in different types ofenvironments with active polarimetric imaging to illustrate the capabilities of the techniques. We demonstratethe effciency of active polarimetric imaging for decamouffage and hazardous object detection, and underlinethe characteristics that a polarimetric imager aimed at this type of application should possess. We show thatin most encountered scenarios the Mueller matrices are nearly diagonal, and suffcient detection performancecan be obtained with simple polarimetric imaging systems having reduced degrees of freedom. Moreover,intensity normalization of images is of paramount importance to better reveal polarimetric contrast
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Grosset, Lucas. "Observations extragalactiques avec optique adaptative : polarisation dans les noyaux actifs de Galaxie et étude des super amas d'étoiles." Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLEO004/document.
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Malgré l’existence de modèles précis, notre connaissance des structures à petite échelle des galaxies est toujours limitée par le manque de preuves observationnelles. Les progrès instrumentaux ont permis d’atteindre une haute résolution angulaire à l’aide des nouvelles générations de télescopes, mais celle-ci est restreinte à un faible nombre de cibles extragalactiques à causes des besoins de l’Optique Adaptative (OA). En effet, afin de permettre une mesure efficace du front d’onde, l’OA requiert une source brillante et ponctuelle proche de la cible scientifique, typiquement en dessous de 30 . La partie principale de cette thèse porte sur l’analyse de la dizaine de parsecs centrale des Galaxies à Noyaux Actifs (NAG) à l’aide de différentes techniques observationnelles et numériques. Nous avons dans ce contexte développé un code de transfert radiatif nous permettant d’analyser les données polarimétriques. La seconde partie de ce travail est dédiée à l’analyse d’images en proche infrarouges de galaxies à flambée d’étoiles afin de contraindre les paramètres décrivant les super amas stellaires, jeunes cocons de poussière très massifs abritant une formation d’étoiles très soutenue, à l’aide de données obtenues avec l’instrument CANARY, démonstrateur de nouvelles technologies d’OA<br>Despite having strong theoretical models, the current limitation in our understanding of the small-scale structures of galaxies is linked to the lack of observational evidences. Many powerful telescopes and instruments have been developed in the last decades, however one of these strongest tools, namely Adaptive Optics (AO), can only be used on a very limited number of targets. Indeed, for AO to be efficient, a bright star is required close to the scientific target, typically under 30 . This is mandatory for the AO systems to be able to measure the atmospheric turbulence and this condition is rarely satisfied for extended extragalactic targets such as galaxies. The main part of this thesis work consisted in going deeper in the analysis of the inner tens of parsecs of Active Nuclei (AGN) by combining different techniques to obtain and to interpret new data. In this context, we developed a new radiative transfer code to analyse the polarimetric data. A second part of my work was dedicated to a high angular resolution study of Super Star Clusters (SSC) in a new system, thanks to data obtained with the AO demonstrator CANARY instrument
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Roche, Denis. "Conception et réalisation d'un capteur piézoélectrique de contraintes de cisaillement pour structure adaptative." Lyon, INSA, 1995. http://www.theses.fr/1995ISAL0062.
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Cette étude concerne la conception, la modélisation et la fabrication de capteurs piézoélectriques destinés à la mesure des contraintes de cisaillement statiques et dynamiques dans les écoulements hydrodynamiques. Les phénomènes qui régissent ces écoulements sont encore mal connus et aucun dispositif ne permet, à ce jour, une mesure précise et fiable des contraintes de frottement sur la paroi. Une étude prospective des différentes solutions envisageables a d'abord été menée. Trois axes de recherche ont été principalement explorés. L'utilisation du mode de cisaillement d'une céramique ferroélectrique s'est avérée d'une sensibilité insuffisante mais nous a permis de déterminer avec précision le coefficient piézoélectrique d l5· Le second volet de nos travaux a été consacré à l'exploitation de la dérive en fréquence d'une ligne à retard à ondes de surface sous l'action d'efforts de cisaillement. Cette étude nous a permis de fixer les limites d'utilisation de ce dispositif Le troisième et dernier axe de recherche a consisté à concevoir et à réaliser un capteur original de type élément flottant, comportant deux ou plusieurs bilames piézoélectriques. La flexion de ces bilames assure la conversion de la force de cisaillement en une charge électrique mesurée à l'aide d'un simple amplificateur de charge. Inspiré de ce principe, un transducteur entièrement enrobé dans une résine polymère, a été optimisé à l'aide de la modélisation par éléments finis puis fabriqué. Ce capteur constitue un matériau composite qui présente les performances requises pour l'application recherchée<br>The scope for our work is the conception, the modelling and the realisation of a piezoelectric sensor for the measurement of static and dynamic shear stresses in hydrodynamic flow. The values of the shear stresses ta be measured in a laminar or a turbulent flow are only of a few Pascal. The usual types of piezoelectric sensors can not perform this measurement with a satisfactory accuracy. Three different solutions have been investigated in out:'thesis work. The use of the shear mode of a piezoelectric ceramic has first been studied. Surface Acoustic Wave (SAW) devices have then been proposed. As these surface waves are very sensitive to external perturbation,. The shear stresses are responsible for a resonance frequency shift. The third device is a floating element type sensor. It consists of a sensing armature, in contact with the flow, and attached ta a fixed one by at least two piezoelectric bimorphs. The floating armature allows the measurement of the drag force counterbalancing the shear effort. This sensor has a high sensitivity and can perform quasi-static and dynamic shear stress measurement using a simple charge amplifier. Another concept, based on the last principle, is the composite transducer. This sensor is entirely embedded and constitutes a composite material, which has the shear stress sensitivity required
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LAVAL, LAURENT. "Modelisation et commande robuste en force d'un actionneur hydraulique confronte d'un environnement incertain : approche h et commande adaptative." Paris 6, 1997. http://www.theses.fr/1997PA066417.
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Ce memoire porte essentiellement sur la problematique de commande en force d'un actionneur hydraulique en presence de dynamiques negligees, de perturbations et de variations comportementales de l'environnement. Apres une breve description du dispositif experimental, une modelisation non lineaire de la servovalve, de l'actionneur et de son environnement est etablie en fonction de phenomenes observes experimentalement. Les parametres de ce modele non lineaire sont ensuite quantifies a partir de procedures definies dans leurs details (notamment un algorithme d'estimation des parametres du modele de tustin relatif a la force de frottement). La validite de la modelisation est alors evaluee au travers de comparaisons de plusieurs comportements experimentaux et simules du systeme. Suite a cette validation, des modeles lineaires de plusieurs ordres pour la commande sont proposes et leur realisme est evalue d'un point de vue frequentiel (notamment, par comparaison avec un modele armax identifie experimentalement). Deux strategies de commande en effort de l'actionneur sont ensuite etudiees et mises en oeuvre. La premiere est fondee sur la synthese de commandes lineaires a parametres fixes suivant l'approche h du probleme de stabilisation robuste (approche h frequentielle puis approche h dans l'espace d'etat - probleme a sensibilite mixte). La seconde est fondee sur la commande adaptative directe avec modele de reference et algorithmes d'adaptation robustes. Derivee de cette derniere etude, deux schemas de commandes adaptatives directes, permettant d'ameliorer le comportement du systeme lors de la phase transitoire d'adaptation des parametres, sont alors proposes et mises en oeuvres. Le premier schema est fonde sur l'introduction de contraintes sur l'evolution de la commande, definies par rapport au comportement de certains parametres estimes. Le second schema est fonde, quant a lui, sur la combinaison d'une commande adaptative avec une commande h a parametres fixes, stigmatisee par une boucle auxiliaire de commande reactive a l'erreur de sortie. In fine, ce memoire comporte l'expression de nos conclusions et de prolongations potentielles de nos travaux.
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Mills, Matthew. "A multipolar polarisable force field method from quantum chemical topology and machine learning." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/a-multipolar-polarisable-force-field-method-from-quantum-chemical-topology-and-machine-learning(3fb1e55c-0d4c-4d11-932b-71706bdbeb8b).html.
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Force field methods are used to investigate the properties of a wide variety of chemical systems on a routine basis. The expression for the electrostatic energy typically does not take into account the anisotropic nature of the atomic electron distribution or the dependence of that distribution on the system geometry. This has been suggested as a cause of the failure of force field methods to reliably predict the behaviour of chemical systems. A method for incorporation of anisotropy and polarisation is described in this work. Anisotropy is modelled by the inclusion of multipole moments centred at atoms whose values are determined by application of the methods of Quantum Chemical Topology. Polarisation, the dependence of the electron distribution on system geometry, is modelled by training machine learning models to predict atomic multipole moments from knowledge of the nuclear positions of a system. The resulting electrostatic method can be implemented for any chemical system. An application to progressively more complex systems is reported, including small organic molecules and larger molecules of biological importance. The accuracy of the method is rigorously assessed by comparison of its predictions to exact interaction energy values. A procedure for generating transferable atomic multipole moment models is defined and tested. The electrostatic method can be combined with the empirical expressions used in force field calculations to describe total system energies by fitting parameters against ab initio conformational energies. Derivatives of the energy are given and the resulting multipolar polarisable force field can be used to perform geometry optimisation calculations. Future applications to conformational searching and problems requiring dynamic descriptions of a system are feasible.
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Bakro, Abdelkarim. "Couplage d'un microscope à effet tunnel photonique à un microscope à force atomique." Montpellier 2, 1998. http://www.theses.fr/1998MON20077.
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La miniaturisation croissante des composants electroniques necessite le developpement de nouvelles techniques de caracterisation operationnelles en dessous du micrometre. Cette these est destinee au couplage d'un microscope a effet tunnel photonique pstm a un microscope a force atomique afm. Apres avoir presente les techniques du champ proche et discute les notions de resolution et de contraste, nous decrivons les modifications apportees au microscope afm (injection de lumiere, detection du signal tunnel) pour qu'il fonctionne simultanement en mode pstm. Des images synchrones afm/pstm pour plusieurs echantillons (defauts reveles sur gaas, reseau grave inp, plots d'or deposes sur inp, guide optique, diode laser) sont presentees et interpretees. Un algorithme de calcul du champ proche optique par la methode etablie du dyadique de green est decrit et implemente en langage c. Les resultats des calculs montrent l'effet de depolarisation revele par d'autres auteurs et aident a interpreter certaines images pstm obtenues.
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Bourget, Pierre. "Coronographie à masque adaptatif pour imagerie et détection à haute dynamique." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4375.
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L’imagerie à très haute dynamique s’applique à de nombreux domaines de recherche en astronomie et astrophysique. Cette problématique observationnelle est abordée sur plusieurs fronts par de nombreuses techniques complémentaires : coronographie, interferométrie, optique adaptative, controle de front d’onde et discrimination des speckles. La combinaison de celles ci permet d’atteindre un haut contraste avec pour ultime objectif l’imagerie d’exoplanètes et l’étude de l’environnement stellaire. Le travail présenté dans ce manuscrit se focalise sur la coronographie et plus particulièrement sur l’optimisation active du procedé d’occultation en fonction du contexte observationnel.La première partie de cette recherche traite de l’observation d’objets résolus par le développement d’un masque focal de Lyot de diamètre variable. La deuxième partie s’applique à étendre le concept du masque focal adaptatif au masque de phase de type Roddier pour l’observation de l’environnement proche d’objets non résolus. L’utilisation des propriétés des cristaux liquides permet de réaliser un déphasage par rotation de polarisation et une modulation de transmission à l’extérieur du masque. Cette modulation permet un controle actif d’optimisation de l’interférence pour une adéquation du masque au contexte observationnel : longueur d’onde, morphologie d’image et défauts intrinsèques au masque, agitation atmosphérique. La dernière partie de ce manuscrit ébauche de nouvelles perspectives quant à la possibilité d’une imagerie à haut contraste. La modulation temporelle de phase transmise par un masque focal adaptatif est mise à profit par l’utilisation des méthodes de détection synchrone<br>High contrast imaging of extra-solar planets and environments of bright astro- physical objects in general, such as stars, active galactic nuclei or objects of the Solar System is a challenging task. Different approaches are needed if the bright region to occult is optically resolved or not. We present the Adaptive Mask concept, observations on sky and numerical simulations show the usefulness of the proposed methods to optimize the efficiency of the coronagraphs for optically resolved or non resolved objects. Accessing small IWA is considered as an edge as it provides substantial scientific and technical advantages. One of the difficulties of accessing small IWA is that coronagraphs become very sensitive to low-order aberrations such as tip-tilt. Our original approach aims at integrating the small IWA capability and the mitigation of sensitivity to low-order aberrations within the coronagraph itself. Our concept is applicable to both low and high Strehl regimes, corresponding to current and next generation AO systems. The adaptive coronagraph can adapt dynamically, in quasi real time, to adjust to the observing conditions to deliver a stable and optimized contrast at the science image level. The mask adaptability both in size, phase and amplitude also compensates for manufacturing errors of the mask itself, and potentially for chromatic effects. The mask adaptability concept using a local phase modulation in the focal plane allows synchronous modulation for high dynamic range synchronous detection of a faint target immersed in a background. The coherence of the speckles with the central star is used to discriminate them from proper companions
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Cowsill, Benjamin James. "The physics of pregnancy tests : a biophysical study of interfacial protein adsorption." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/the-physics-of-pregnancy-tests-a-biophysical-study-of-interfacial-protein-adsorption(538b8e9c-9111-4eb9-ac7d-e5e75110e315).html.
Full textAbstract:
Pregnancy tests and related immunoassays are heavily dependent on specific and non-specific protein adsorption. These interfacial processes are affected by many factors that influence the in situ conformations of interfacially immobilised antibodies. This thesis examines a number of representative features with dual polarisation interferometry (DPI) and neutron reflection (NR), thus combining real-time dynamic monitoring with high interfacial structural resolution. Bovine serum albumin (BSA) was initially used as a model system to compare the surface coverage and thickness measurements of DPI and NR. The results show that DPI and NR provided similar surface coverage data but the measured thicknesses differed at BSA concentrations above 0.1 mg/ml. This discrepancy arose from the adoption of the uniform-layer model used by DPI for data analysis and the greater thickness sensitivity of NR. A model pregnancy immunoassay was built in steps on a silica surface so that the adsorption of each protein could be accurately monitored. Both DPI and NR provided evidence of BSA insertion into the gaps on the surface between the antibody molecules. This suggests that BSA adsorption is an excellent method to block the non-specific adsorption of target antigens to the immunoassay test surface. A magnetic tweezer system was designed and built in order to measure the specific antibody/antigen binding force. The antibodies and antigens were used to immuno-link magnetic beads to the experimental surface before the immuno-links were broken by increasing the attractive force between the magnetic tweezers and beads. The force per antibody/antigen immuno-link was estimated to lie between the values of 13.6 pN and 43.8 pN.Immuno-link detachment as a function of time was investigated. It was found that the immuno-link comprised both a strong and a weak interaction. The dissociation constant of the strong antibody/antigen interaction was found to equal 3E-4 /s and had an interaction length of 0.06 nm. The low population of beads bound by the second, weaker interaction meant that it was not possible to obtain accurate values of the dissociation constant and bond length of the second weaker interaction.
Books on the topic "Force de polarisation adaptative"
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Mariuzzo, Andrea. Communism and anti-Communism in early Cold War Italy. Manchester University Press, 2018. http://dx.doi.org/10.7228/manchester/9781526121875.001.0001.
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The struggle in projects, ideas and symbols between the strongest Communist Party in the West and an anti-Communist and pro-Western government coalition was the most peculiar founding element of the Italian democratic political system after World War II. Until now, most historians have focused their attention on political parties as the only players in the competition for the making of political orientations and civic identities in Italian public opinion. Others have considered Italian political struggle in the 1940s and 1950s in terms of the polarisation between Communism and organized Catholicism, due to the undoubted importance of the Church in Italian culture and social relations. This book enlarges the view, looking at new aspects and players of the anti-Communist ‘front’. It takes into account the role of cultural associations, newspapers and the popular press in the selection and diffusion of critical judgements and images of Communism, highlighting a dimension that explains the force of anti-communist opinions in Italy after 1989 and the crisis of traditional parties. The author also places the case of Italian Cold War anti-Communism in an international context for the first time.
Book chapters on the topic "Force de polarisation adaptative"
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Fukuda, T., N. Kitamura, and K. Tanie. "Adaptative Force Control of Grippers Taking into Account the Dynamics of Objects." In RoManSy 6. Springer US, 1987. http://dx.doi.org/10.1007/978-1-4684-6915-8_28.
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Oulaï, Arthur, and Serge Kablan. "Usages de l’internet et divulgation adaptative des clauses contractuelles : la force exécutoire de l’iconographie." In Customary Law Today. Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-73362-3_14.
Full textConference papers on the topic "Force de polarisation adaptative"
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Liang, Ruquan, and Satoru Komori. "Computation of a Propagating Interface in Multiphase Flows Using an Adaptive Coupled Level Set Method." In ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-39044.
Full textAbstract:
We present a numerical strategy for a propagating interface in multiphase flows using a level set method combined with a local mesh adaptative technique. We use the level set method to move the propagating interface in multiphase flows. We also use the local mesh adaptative technique to increase the grid resolution at regions near the propagating interface and additionally at the regions near points of high curvature with a minimum of additional expense. For illustration, we apply the adaptive coupled level set method to a collection of bubbles moving under passive transport. Good agreement has been obtained in the comparision of the numerical results for the collection of bubbles using an adaptative grid with those using a single grid. We also apply the adaptive coupled level set method to a droplet falling on a step where it is important to accurately model the effect of surface tension force and the motion of the free-surface, and the numerical results agree very closely with available data.