Les systèmes de navigation par satellite (GNSS) font partie de notre quotidien. On peut présentement les trouver dans un ensemble d’applications. Avec les nouveaux besoins, des nouveaux enjeux sont aussi apparus : le traitement du signal dans les environnements urbains est extrêmement complexe. Dans cette thèse, le traitement des signaux GNSS à faible puissance est abordé, en particulier dans la première phase du traitement, nommé acquisition de signal. Le premier axe de rechercheporte sur l’analyse et la compensation de l’effet Doppler dans l’acquisition. Le décalage Doppler perçu par l’utilisateur est un des paramètres principaux pour la configuration du module d’acquisition. Dans cette étude, des solutions sont proposées pour trouver le meilleur compromis sensibilité-complexité propre à l’acquisition. En deuxième axe, la caractérisation des détecteurs différentiels est abordée, en particulier la quantification de sa sensibilité. Pour l’acquisition des signaux faibles, après une première phase d’intégration cohérente, il faut passer par une intégration «postcohérente» (noncohérente ou différentielle.) L’analyse exécutée ici permet de meilleur identifier le meilleur choix entre les deux possibilités. Le troisième axe de recherche est consacré à la méthode de Détection Collective (CD), une innovation qui fait l’acquisition simultanée de tous les signaux visible par le récepteur. Plusieurs analyses sont réalisées incluant l’amélioration de la procédure de recherche de la CD, et l’hybridisation avec l’acquisition standard. Enfin on effectuel’analyse de la CD dans un contexte multi-constellation, en utilisant simultanément des vrais signaux GPS et Galileo. / Satellite navigation (GNSS) is a constant in our days. The number of applications that depend on it is already remarkable and is constantly increasing. With new applications, new challenges have also risen: much of the new demand for signals comes from urban areas where GNSS signal processing is highly complex. In this thesis the issue of weak GNSS signal processing is addressed, in particular at the first phase of the receiver processing, known as signal acquisition. The first axe of research pursued deals with the analysis and compensation of the Doppler effect in acquisition. The Doppler shift that is experienced by a user is one of the main design drivers for the acquisitionmodule and solutions are proposed to improve the sensitivity-complexity trade-off typical of the acquisition process. The second axe of research deals with the characterization of differential GNSS detectors. After a first step of coherent integration, transition to post coherent (noncoherent or differential) integration is required for acquiring weak signals. The quantification of the sensitivity of differential detectors was not found in literature and is the objective of this part of the research. Finally, the third axe of research is devoted to multi-constellation Collective Detection (CD). CD is an innovative approach for the simultaneous processing of all signals in view. Severalissues related to CD are addressed, including the improvement of the CD search process and the hybridization with standard acquisition. Finally, the application of this methodology in the context of a multi-constellation receiver is also addressed, by processing simultaneously real GPS and Galileo signals.

L’avènement du Génie électrique, il y a plus d’un siècle maintenant, s’est accompagné dès ses débuts, de recherche de matériaux ferromagnétiques performants pour la réalisation de l’élément central des dispositifs électromagnétiques, le circuit ou noyau magnétique. Ces matériaux, constitués initialement de fer, ont été très vite alliés au silicium, au cobalt et au nickel pour plusd’efficacité énergétique. Pour un dispositif donné, le choix d’un tel ou tel matériau passe souvent par un exercice de compromis vis-à-vis des besoins applicatifs (performances magnétiques, caractéristiques mécaniques et thermiques, etc., et bien sûr coût). La fréquence et la température de fonctionnement sont entre autres des paramètres importants. Parmi ces matériaux, les FeNi, bien qu’ils soient matures industriellement, voient toujours de nouveaux marchés s’ouvrirent à eux année après année grâce à l’attrait technique qu’ils exercent. Ce travail s'inscrit dans la continuité des recherches engagées à AMPERE sur les modèles comportementaux de matériaux magnétiques avec prise en compte des effets de la température. En effet, la recherche permanente de performances et de compacité ou intégration pour tous les dispositifs électromagnétiques soumet les circuits magnétiques à des contraintes physiques et en particulier thermiques de plus en plus sévères. Il est donc nécessaire de caractériser et modéliserprécisément les matériaux ferromagnétiques, et plus particulièrement les alliages FeNi, afin de les intégrer dans les outils de conception et d’optimisation de ces dispositifs. Pour cela, nous avons notamment dû mettre en oeuvre un dispositif expérimental adapté, et réaliser de nombreuses et longues expérimentations afin d’élaborer des modèles performants de comportement de ces matériaux. Ces modèles étudiés ou/et développés ont été ensuite testés sur une démonstrateur réel. Dans le cadre de cette thèse qui s’est déroulée en collaboration avec le Centre de Recherche du groupe APERAM, nous avons choisi une application particulièrement sensible en matière de sécurité des personnes « le système de protection différentielle » où le circuit magnétique (en alliage Fe–50%Ni ou Supra50) constitue une part très importante des performances et de la fiabilité. Enfin, de nouveaux alliages FeNi(Cr, Cu) à faible teneur en Ni (donc économiques) issus du Centre de Recherche d’APERAM ont été étudiés en vue de tester leur aptitude à remplacer le Supra50 dans ces systèmes. Le but est au final de proposer des alliages FeNi économiques aptesà la fabrication du circuit magnétique des relais de disjoncteurs différentiels à propre courant. / The advent of Electrical Engineering has been accompanied since its beginning, by the research of high performance ferromagnetic materials for the realization of the central element of electromagnetic devices, the magnetic core/circuit. These materials initially consisting of iron were alloyed with silicon, cobalt and nickel for more energy efficiency. For a given device, the material must be designed to meet the requirements of the application (magnetic performances, mechanical and thermal characteristics...and cost. The frequency and the operating temperature are, among others, important parameters to be taken into account. Among these materials, the FeNi alloys, although they are industrially mature, see new markets opened to them thanks to their certain specific characteristics and the innovations brought by the manufacturers of these materials. This work is a continuation of ongoing researches in AMPERE laboratory dealing with thebehavioral models of magnetic materials taking into account the effects of temperature. Indeed, there is a trend in a growing number of electromagnetic devices to require high performance and compactness or integration. Thus, in this context, the magnetic circuits are subjected to physical and thermal stresses that are becoming more and more stringent. It is therefore necessary to resort to the experimental characterization and modeling of the behavior of ferromagnetic materials, particularly the FeNi alloys, in order to integrate them into the design and optimization tools of these devices. To do so, we have implemented an appropriate experimental bench, andachieve many and long experiments to develop advanced behavioral models of these materials. These models were then tested on a particularly sensitive application in the field of safety of persons, the differential protection system where the magnetic circuit (of Fe-50% Ni or Supra50) is a very important part of performance and reliability. Finally, new low Ni content FeNi (Cr, Cu) alloys provided by Aperam Research Center in Imphy, were studied in order to test their ability to replace the usual Supra50 alloy in these systems. The final aim is to propose new economic FeNi alloys suitable for the manufacture of the magnetic circuit of industrial ground fault circuit-breaker relay.

Control and analysis of protein aggregation is an increasing challenge to biopharmaceutical research and development. Therefore it is important to understand the interactions, causes and analysis of particles in order to control protein aggregation to enable successful biopharmaceutical formulations. This work investigates the role of different non-ionic surfactants on protein conformational stability, as assessed by HSDSC, and on protein size stability as assessed by Dynamic Light Scattering (DLS), HIAC and MFI. BSA and IgG2 were used as model proteins. Thermal unfolding experiments indicated a very weak surfactant-immunoglobulin IgG2 interaction, compared to much stronger interactions for the BSA surfactant systems. The DLS results showed that BSA and IgG2 with different surfactants and concentration produced different levels of particle size growth. The heat treatment and aging of samples in the presence of Tween 20, Tween 80, Brij 35 and Pluronic F-68 surfactants led to an increase in the populations of larger particles for BSA samples, whereas IgG2 systems did not notably aggregate under storage conditions MFI was shown to be more sensitive than HIAC technique for measuring sub-visible particles in protein surfactant systems. Heat treatment and storage stress showed a significant effect on BSA and IgG2 protein sub-visible particle size stability. This work has demonstrated that both proteins with different Tween 20, Tween 80, Brij 35 and Pluronic F-68 concentrations, have different level of conformational and size stability. Also aging samples and heating stress bears the potential to generate particles, but this depends on surfactant type. Poor predictive correlations between the analytical methods were determined.

Endotelio funkcijos sutrikimas (disfunkcija) - būklė, apibūdinama padidėjusia adhezijos molekulių ekspresija, padidėjusia prouždegiminių veiksnių ir protrombotinių faktorių sinteze bei sutrikusia kraujagyslių tono reguliacija - yra mirties dėl kardiovaskulinės patologijos, miokardo infarkto bei poreikio revaskuliarizacijos procedūroms išsivystymo rizikos veiksnys. Darbo tikslas buvo nustatyti endotelio pažeidimą atspindinčių žymenų, hs-CRP, sVCAM-1 ir sICAM-1 reikšmę, nuspėjant kardiovaskulines komplikacijas po aortos vainikinių jungčių suformavimo operacijos, atliktos dirbtinės kraujo apytakos sąlygomis. Nustatėme, kad didesnės priešoperacinės hs-CRP ir sVCAM-1 koncentracijos buvo nepriklausomi didesnės kardiovaskulinių komplikacijų po aortos vainikinių jungčių suformavimo operacijų rizikos žymenys. Po aortos vainikinių jungčių suformavimo operacijos nustatyta reikšmingai didesnė hs-CRP, sVCAM-1 ir sICAM-1 koncentracija, palyginus su priešoperaciniu koncentracijos lygiu. Patikimos žymenų koreliacijos su aortos užspaudimo, dirbtinės kraujo apytakos bei operacijos trukme neradome. Pacientams po aortos vainikinių jungčių suformavimo operacijos koreliacijos tarp pooperacinio sICAM-1, sVCAM-1 bei hs-CRP koncentracijos lygio ir kardiovaskulinių komplikacijų išsivystymo rizikos nebuvo nenustatyta. / The endothelial cell damage/dysfunction is associated with increased expression of adhesion molecules, synthesis of proinflammatory, prothrombotic factors and abnormal modulation of vascular tone. A growing body of evidence suggests that endothelial dysfunction is associated with future cardiovascular events including cardiac death, myocardial infarction and the need for revascularization procedures. The aim of the study was to evaluate the impact of markers of endothelial damage as predictors of cardiovascular events after on-pump coronary artery bypass grafting surgery. We found that higher concentrations preoperatively of hs-CRP and sVCAM-1 were independent markers for higher risk of cardiovascular events after coronary artery bypass grafting surgery. Concentration of hs-CRP, sVCAM-1 and sICAM-1 increased significantly after on-pump coronary artery bypass grafting surgery compared to preoperative level. However correlation between the duration of aortic cross-clamp, cardiopulmonary bypass or surgery and markers of endothelial damage was not found. Correlation between postoperative concentration of hs-CRP, sVCAM-1 and sICAM-1 and risk for cardiovascular events after coronary artery bypass grafting surgery was not found.

Endotelio funkcijos sutrikimas (disfunkcija) - būklė, apibūdinama padidėjusia adhezijos molekulių ekspresija, padidėjusia prouždegiminių veiksnių ir protrombotinių faktorių sinteze bei sutrikusia kraujagyslių tono reguliacija - yra mirties dėl kardiovaskulinės patologijos, miokardo infarkto bei poreikio revaskuliarizacijos procedūroms išsivystymo rizikos veiksnys. Darbo tikslas buvo nustatyti endotelio pažeidimą atspindinčių žymenų, hs-CRP, sVCAM-1 ir sICAM-1 reikšmę, nuspėjant kardiovaskulines komplikacijas po aortos vainikinių jungčių suformavimo operacijos, atliktos dirbtinės kraujo apytakos sąlygomis. Nustatėme, kad didesnės priešoperacinės hs-CRP ir sVCAM-1 koncentracijos buvo nepriklausomi didesnės kardiovaskulinių komplikacijų po aortos vainikinių jungčių suformavimo operacijų rizikos žymenys. Po aortos vainikinių jungčių suformavimo operacijos nustatyta reikšmingai didesnė hs-CRP, sVCAM-1 ir sICAM-1 koncentracija, palyginus su priešoperaciniu koncentracijos lygiu. Patikimos žymenų koreliacijos su aortos užspaudimo, dirbtinės kraujo apytakos bei operacijos trukme neradome. Pacientams po aortos vainikinių jungčių suformavimo operacijos koreliacijos tarp pooperacinio sICAM-1, sVCAM-1 bei hs-CRP koncentracijos lygio ir kardiovaskulinių komplikacijų išsivystymo rizikos nebuvo nenustatyta. / The endothelial cell damage/dysfunction is associated with increased expression of adhesion molecules, synthesis of proinflammatory, prothrombotic factors and abnormal modulation of vascular tone. A growing body of evidence suggests that endothelial dysfunction is associated with future cardiovascular events including cardiac death, myocardial infarction and the need for revascularization procedures. The aim of the study was to evaluate the impact of markers of endothelial damage as predictors of cardiovascular events after on-pump coronary artery bypass grafting surgery. We found that higher concentrations preoperatively of hs-CRP and sVCAM-1 were independent markers for higher risk of cardiovascular events after coronary artery bypass grafting surgery. Concentration of hs-CRP, sVCAM-1 and sICAM-1 increased significantly after on-pump coronary artery bypass grafting surgery compared to preoperative level. However correlation between the duration of aortic cross-clamp, cardiopulmonary bypass or surgery and markers of endothelial damage was not found. Correlation between postoperative concentration of hs-CRP, sVCAM-1 and sICAM-1 and risk for cardiovascular events after coronary artery bypass grafting surgery was not found.

With the increasing importance of hand-held devices with touch displays, the need for flat panel displays (FPDs) will likely increase in the future. Glass is the most important substrate for FPD manufacturing, where both its bulk and surface properties are critical for its performance. Many properties of the glass used in FPDs are controlled by its surface chemistry. Surface hydroxyls are the most important functional groups on a glass surface, which control processes that occurs on oxide surfaces, including wetting, adhesion, electrostatic charging and discharge, and the rate of contamination. In this dissertation, I present a new approach for determining surface silanol densities on planar surfaces. This methodology consists of tagging surface silanols using atomic layer deposition (ALD) followed by low energy ion scattering (LEIS) analysis of the tags. The LEIS signal is limited to the outermost atomic layer, i.e., LEIS is an extremely surface sensitive technique. Quantification in LEIS is straightforward in the presence of suitable reference materials. An essential part of any LEIS measurement is the preparation and characterization of the sample and appropriate reference materials that best represent the samples. My tag-and-count method was applied to chemically and thermally treated fused silica. In this work, I determined the silanol density of a fully hydroxylated fused silica surface to be 4.67 OH/nm2. This value agrees with the literature value for high surface area silica powder. My methodology should be important in future glass studies. Surface Science Spectra (SSS) is an important, peer-reviewed database of spectra from surfaces. Recently, SSS has been expanding to accept spectra from new surface techniques. I created the first SSS submission form for LEIS spectra (see appendix 5), and used it to create the first SSS LEIS paper (on CaF2 and Au reference materials, see chapter 3). I also show LEIS reference spectra for ZnO, and copper in the appendix 1. The rest of my dissertation focuses on my chemometrics/informatics and data analysis work. For example, I showed the performance and capabilities of a series of summary statistics as new tools for unsupervised exploratory data analysis (EDA) (see chapter 4). Unsupervised EDA is often the first step in understanding complex data sets because it can group, and even classify, samples according to their spectral similarities and differences. Pattern recognition entropy (PRE) and other summary statistics are direct methods for analyzing data - they are not factor-based approaches like principal component analysis (PCA) or multivariate curve resolution (MCR). I show that, in general, PRE outperforms the other summary statistics, especially in image analysis, although I recommend a suite of summary statistics be used in exploring complex data sets. In addition, I introduce the concept of divided spectrum-PRE (DS-PRE) as a new EDA method and use it to analyze multiple data sets. DS-PRE increases the discrimination power of PRE. I have also prepared a guide that discusses the vital aspects and considerations for chemometrics/informatics analyses of XPS data along with specific EDA tools that can be used to probe XPS data sets, including PRE, PCA, MCR, and cluster analysis (see chapter 5). I emphasize the importance of an initial evaluation/plotting of raw data, data preprocessing, returning to the original data after a chemometrics/informatics analysis, and determining the number of abstract factors to keep in an analysis, including reconstructing the data using PCA. In my thesis, I also show the analysis of commercial automotive lubricant oils (ALOs) with various chemometrics techniques (see chapter 6). Using these methods, the ALO samples were readily differentiated according to their American Petroleum Institute (API) classification and base oil types: mineral, semi-synthetic, and synthetic.