The presented thesis focused on the study of a new material concept of Ce3+ doped multicom- ponent aluminum garnets (GdLu)3(GaAl)5O12. High purity single crystalline epitaxial films were grown by the method of liquid phase epitaxy from the BaO-B2O3-BaF2 flux with spe- cial emphasis on the elimination of the potential impurities coming from the flux. Combined experimental study of photoelectron yield (under alpha excitation), decay kinetics of fast and delayed recombination in the milisecond time range (under e-beam excitation) and photo-, cathodo- and radio-luminescence spectroscopies were used to characterize the studied mater- ial. The single-step nonradiative energy transfer from the donor Gd3+ to an acceptor Ce3+ was observed in the low Gd, Ce doped LuAG films and established as long-range dipole - dipole interaction. Special attention was devoted to the positive effect of combined Gd and Ga substitution on the extensive suppression of shallow traps, which are responsible for the slow component in the scintillation response. The best obtained scintillation characteristics of the studied epitaxial films were comparable with the top performance bulk crystals. 1

This thesis focuses on the study of graphene application in electronics and technology of preparation. In addition to the basic properties of graphene, the theoretical part of the work also describes the methods of its preparation, transmission, characterization and possibilities of application in electronics. The experimental part is divided into three chapters. The first chapter deals with the production of graphene by deposition from the gaseous phase, its transmission and application in the field of solar cells. The Poly(methyl methacrylate) polymer was first used for transfer of graphene, which was later replaced by Rosin due to less contamination of graphene at the end of the transmission process. The second chapter deals with the preparation of quantum dots by exfoliation in the liquid phase from graphite and its application in voltammetry. Voltammetry was utilized in this work to detect hydrogen peroxide using a gold electrode modified by quantum dots from graphene and other dichalcogens (MoS2, MoSe2, WS2, WSe2). In the last chapter, the influence of the substrate and the deposition conditions of graphene is studied by means of a plasma-reinforced phase-out of gas to growth, while the prepared graphene was characterized by imaging and spectroscopic methods. The entire experimental growth of graphene was managed and evaluated using a planned experiment.

La segmentation de maillages polygonaux est un outil nécessaire à de nombreuses applications. Elle correspond au découpage du maillage en régions à partir d'informations portant sur la surface ou la forme globale de l'objet. Ces dernières années, de nombreux algorithmes ont été proposés dans cette thématique en large expansion. Les applications sont très variées; citons la reconnaissance de forme, l'indexation, la compression, la métamorphose, la détection de collision, le plaquage de texture, la simplification, etc.<br /><br />Nous proposons dans un premier temps une étude assez large des méthodes de segmentation de maillages polygonaux. Nous abordons les algorithmes pour les deux principales familles de méthodes que sont la segmentation en carreaux surfaciques et la segmentation en parties significatives. Nous avons concentré nos travaux sur la ligne de partage des eaux (LPE) et formulé des propositions originales pour la fonction de hauteur de la LPE et des stratégies pour limiter la sur-segmentation que produit naturellement la LPE.

Current methods for preparing graphene quantum dots (GQDs) rely on oxidation and reducing agents or require energy-intensive and technologically demanding preconditions. Applying microwave expansion and liquid phase exfoliation (LPE) in a sample of graphite powder enabled us to prepare GQDs that exhibit strong luminescence in the blue region of the visible spectrum. The proposed technique for synthesizing GQDs is energetically undemanding and does not necessitate additional chemical components.

Depuis les années 1970, le développement des sources lasers de puissance fonctionnant autour de 2 µm basées sur des cristaux dopés Thulium Tm3+ et/ou Holmium Ho3+est un domaine de recherche actif du fait de ses multiples applications. L’émission autour de 1.9 µm correspond à une transition du niveau excité 3F4 vers le niveau fondamental 3H6 dans un ion trivalent Tm3+, alors que l’émission à 2 µm et au-delà correspond à la transition entre le niveau 5I7 et le niveau fondamental 5I8 de l’ion Ho3+. Ces transitions laser font aujourd’hui l’objet de nombreuses applications dans domaines très variés. nous avons étudié les propriétés spectroscopiques de cristaux de fluorures dopés terres rares en vue d’une émission autour de 2 µm. À partir des spectres d’absorption obtenus, l’analyse de Judd-Ofelt a permis de calculer les durées de vie radiatives ainsi que les rapports de branchement dans les ions Tm3+ et Ho3+. En comparaison avec d’autres cristaux tels que les oxydes, les durées de vie des niveau 3F4(Tm3+) et 5I7(Ho3+) dans les cristaux de fluorures sont plus longues ce qui favorise un fonctionnement laser en régime impulsionnel. Une étude sur la dynamique de fluorescence a été réalisée afin de caractériser l’émission autour de 1.9µm de l’ion Tm3+ et celle autour de 2µm de l’ion Ho3+. Les spectres d’émission obtenus offrent de larges bandes, assez structurées dans la matrice LiYF4 et plus larges et moins structurées dans la matrice CaF2. Dans un second temps, en mesurant les durées de vie du niveau émetteur 3F4 pour différentes concentrations en ions Tm3+, nous avons calculé les paramètres de transferts. Les résultats obtenus ont montré que le processus de relaxation croisée est beaucoup plus efficace dans le cristal CaF2 que dans le LiYF4. Nous avons calculé également les coefficients de transfert et de transfert inverse entre les ions Tm3+ et Ho3+ suite à une excitation de l’ion Tm3+. Nous avons montré que la matrice LiYF4 offre une meilleure efficacité de transfert en vue d’une émission autour de 2µm. Le fonctionnement laser de couches minces en configuration « disque mince » a été étudié. Une première démonstration d’un laser en disque mince LiYF4 : Tm émettant à 1.9 µm réalisé à partir d’une couche épitaxiée par LPE a été faite. En simple passge, une puissance de sortie de 306 mW et une efficacité laser de 36% en puissance absorbée sont atteintes pour une couche de 240 μm d'épaisseur.nous avons étudié un oscillateur laser en guide d’onde LiYF4 :Tm en géométrie planaire et linéaire. Ces guides sont caractérisés par de faibles pertes de propagation grâce à la qualité du procédé de fabrication. Une puissance maximale de 470 mW et un rendement de 14% en puissance incidente ont été obtenus. Une modélisation numérique de l’amplification optique montre que le guidage des faisceaux pompe et sonde permet d’atteindre des gains importants. Le modèle est ensuite adapté pour le régime de saturation afin de calculer le rendement d’extraction et de déterminer le potentiel des guides LiYF4 :Tm3+ en tant comme amplificateur autour de 1.9 µm / Since the 1970s, the development of power laser sources operating around 2 μm based on Thulium Tm3 + and / or Holmium Ho3 + doped crystals is an active field of research because of its multiple applications. The emission around 1.9 μm corresponds to a transition from the excited level 3F4 to the fundamental level 3H6 in a trivalent ion Tm3 +, whereas the emission at 2 μm and beyond corresponds to the transition between the level 5I7 and the fundamental level 5I8 of the Ho3 + ion. These laser transitions are today the subject of many applications in a wide variety of fields. We have studied the spectroscopic properties of rare earth doped fluoride crystals for emission around 2 μm. From the absorption spectra obtained, the Judd-Ofelt analysis made it possible to calculate the radiative lifetimes as well as the branching ratios in the Tm3 + and Ho3 + ions. In comparison with other crystals such as oxides, the lifetimes of the 3F4 (Tm3 +) and 5I7 (Ho3 +) levels in the fluoride crystals are longer, which favors pulse-mode laser operation. A study on fluorescence dynamics was carried out in order to characterize the emission around 1.9 μm of the Tm3 + ion and that around 2 μm of the Ho3 + ion. The emission spectra obtained have broad bands, fairly structured in the LiYF4 matrix and wider and less structured in the CaF2 matrix. In a second step, by measuring the lifetimes of the 3F4 emitter level for different Tm3 + ion concentrations, we calculated the transfer parameters. The results obtained showed that the process of cross relaxation is much more efficient in the CaF2 crystal than in LiYF4. We also calculated the transfer and inverse transfer coefficients between Tm3 + and Ho3 + ions following excitation of the Tm3 + ion. We have shown that the LiYF4 matrix offers a better transfer efficiency with a view to emission around 2 μm. The laser operation of thin layers in "thin disc" configuration has been studied. A first demonstration of a thin-film LiYF4: Tm laser emitting at 1.9 μm made from an epitaxial layer with LPE was made. In single passge, an output power of 306 mW and a laser efficiency of 36% in absorbed power are reached for a 240 μm thick layer. We have studied a laser oscillator in LiYF4: Tm waveguide in planar geometry. and linear. These guides are characterized by low propagation losses thanks to the quality of the manufacturing process. A maximum power of 470 mW and a yield of 14% in incident power were obtained. A numerical modeling of the optical amplification shows that the guidance of the pump and probe beams makes it possible to achieve significant gains. The model is then adapted for the saturation regime in order to calculate the extraction efficiency and to determine the potential of the LiYF4: Tm3 + guides as an amplifier around 1.9 μm

In this work we studied properties of garnet scintillator layers (RxLu3-xAl5O12, RxY3-xAl5O12) doped by rare earth ions (Ce, Pr, Tb), orthosilicates (Y2SiO5; R = Ce, Tb) and influence of Sc codoping on Pr3+ and Tb3+ emissions. The Zr codoping on Ce3+ emission in orthosilicates was also studied. The samples were prepared by liquid phase epitaxy. The studied materials show high quantum efficiency and good chemical and mechanical stability. They represent ideal materials for 2D imaging devices. We studied optical absorption, excitation and emission spectra and scintillation properties (radiolunescence and photoelectron yield). The aim was to determine the properties of grown layers and their comparison to Czochralski grown single crystals. We looked for the impact of melt and growth conditions on measured layer properties. We also tried to determine optimal amount of dopants in layer. We used PbO - B2O3 and BaO - BaF2 - B2O3 fluxes. Using these fluxes, we succeeded in growing layers with less intrinsic defects in crystal lattice in comparison to single crystals. In grown layers of thickness from 1 to 30 µm higher dopant concentration was achieved than in single crystals.

Piezoelectric materials are well known for their applications in surface (SAW) and bulk acoustic wave (BAW) devices such as oscillators, resonators and sensors. Quartz has been the main material used in such applications. Ternary calcium gallium germanate (CGG) structure-type materials, so-called langasites, recently emerged as very promising because of their piezoelectric properties superior to quartz. This thesis discusses the growth of langasite-type La3Ga5.5Ta0.5O14 (LGT) films by liquid phase epitaxy (LPE) technique and their chemical and structural characterization. In addition, the different techniques suitable for the growth of LGT are discussed and compared. To adjust the materials properties for given applications, doping by selected ions can be used. However, the dopants must be homogeneously distributed. In the current study, Al, Ti, Cr and Ca were investigated as dopants. In an earlier study, Al and Ti had been chosen because of their ability to substitute the octahedral site of LGT, normally occupied by Ga (CN=VI) with a segregation coefficient near unity in Czochralski growth. Doping with Ca and Cr has never been reported before, and therefore, the segregation behavior was unknown. In this study, Al, Ti and co-doping with Cr and Ca has been investigated for both X and Y-oriented films. The dopant distribution in the films was quantitatively evaluated by Secondary Ion Mass Spectroscopy (SIMS), using ion-implanted LGT substrates as standards. The drop of dopant concentration, in the SIMS profile, allows for the identification of the film-substrate interface and to accurately measure the thickness of the films. The film thickness is found to be typically of the order 0.5 to 2µm, depending on growth conditions. The solvent was found a reliable choice, as solvent ions were not incorporated in the films above the detection limits of the characterization techniques. A lead oxide solvent system is used as a solvent for the growth of LGT LPE films with different orientations. Extensive structural characterization was performed. The crystallinity of substrates and films grown with different orientations was compared by X-ray diffraction (XRD). The films show a very high structural perfection, with typically FWHM values of 0.035 for the (004) reflection of the XRD rocking curve. The films were also characterized by TEM. The optical transmittance of the films was characterized by Varian optical spectrophotometer, and the value obtained of approximately 80% is comparable with the transmittance value of the Czochralski grown polished substrate.

Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Pharmacology & Toxicology Student: Alžbeta Horvátová Supervisor: prof. PharmDr. Petr Pávek PhD. Title of diploma thesis: Anti-inflammatory effects of ursodeoxycholyl lysophosphatidylethanolamide on THP-1 human macrophages via Toll-like receptor 4 Nonalcoholic steatohepatitis (NASH) became the most common liver disease in developed countries. It is well-known that the level of protectant phosphatidylcholine (PC) is decreased in NASH. The bile acid-phospholipid conjugate ursodeoxycholyl lysophosphatidylethanolamide (UDCA-LPE) was designed in order to specifically deliver PC to hepatocytes. However, previous studies have proved that UDCA-LPE possesses its proper hepatoprotectant capacity and exhibits anti-apoptotic, anti-inflammatory, anti-fibrotic properties and also improved steatosis and hyperlipidaemia in various models in vivo. These effects may be mediated secondary through modulation of immune system. Therefore, in order to dissect if UDCA-LPE directly influences immune cells in vitro, release of pro-inflammatory cytokines TNFα, IL-6 and IL-1β in LPS-induced THP-1-derived human macrophages was measured by ELISA. Moreover, effects of UDCA-LPE on MAPK signalling pathways and nuclear translocation of NFκB were...

<p>  </p> <p>Graphene is a two-dimensional (2-D) sheet of <em>sp2</em> hybridized carbon atoms with extraordinary thermal, electrical, and mechanical properties. Among numerous sophisticated and costly synthesis techniques including chemical vapor deposition (CVD), SiC and microwave plasma; liquid-phase exfoliation (LPE) has been one of the most widely used techniques for low-cost and large scale graphene synthesis since it was first reported in 2008. LPE involves the use of liquid media to exfoliate graphite precursors directly into mono- or few-layered graphene. Stable dispersions of few-layered graphene are desirable for thin-film deposition on a large scale but are limited by the use of polar organic solvents with high boiling points and unfavorable toxicity profiles. This limitation can be overcome by milling and exfoliation of graphene nanoplatelets (GrNPs) in ethyl acetate (EtOAc) and acetone, volatile solvents with low toxicity profiles and modest environmental impact. Solvent-assisted grinding of pristine GrNPs on a horizontal ball mill followed by sonication produces concentrated suspensions up to 356 µg/mL that remain stable at room temperature for a minimum of 6 weeks without the addition of surfactants. Exfoliated graphene layers have an average thickness of 4.5 nm which corresponds to 10–12 layers of graphene on Si/SiO2 substrates. EtOAc and acetone-based dispersions of exfoliated graphene can be deposited uniformly using conventional airbrush equipment as low-boiling point solvents evaporates instantaneously after deposition. This deposition method also provides freedom regarding to target substrate and overcomes any substrate related limitations observed in other techniques. Practical demonstrations of spray-coated graphene films include (i) conductive surfaces with sheet resistance as low as 1 kΩ/sq, and (ii) solid contacts for disposable and low-cost nitrate-selective electrodes, with high reproducibility in the voltage readouts across multiple sensors.</p>

D’un point de vue général, les travaux de recherche de cette thèse s’inscrivent dans le cadre d’une approche globale quiconsiste à extraire des informations relatives aux toitures de bâtiments à partir de photos aériennes (orthophotoplans). L’objectifétant de pouvoir reconnaître des toitures extraites d’images aériennes en utilisant une base de connaissances, puisaffiner/déformer des modèles 3D générés automatiquement à partir de données géographiques. Pour cela, une premièreétape consiste tout d’abord à partitionner l’image aérienne en différentes régions d’intérêt (pans de toiture, cheminées,chiens assis, fenêtres, etc.), c’est la contribution de cette thèse.La méthodologie permettant d’atteindre cet objectif est composée de trois étapes : (i) Une étape de simplification qui consisteà simplifier l’image initiale avec un couple invariant/gradient approprié et optimisé pour l’application. Pour cela, unesérie de tests permettant de choisir, d’une part, l’invariant colorimétrique le plus approprié parmi 24 invariants et, d’autrepart, le meilleur gradient parmi 14 gradients issus de la littérature est réalisée. (ii) La deuxième étape comporte deux stratégiesde segmentation par LPE. L’image simplifiée est segmentée d’une part par une LPE-régions couplée à une stratégiede fusion de régions, et d’autre part, par une LPE-contours. Le processus de fusion de régions intègre des critères defusion fondés sur des grandeurs radiométriques et géométriques adaptés aux particularités des orthophotoplans traités.Une technique de caractérisation 2D des arêtes de toitures par une analyse des segments est proposée afin de calculerl’un des critères de fusion. (iii) La troisième étape consiste à combiner les avantages de chaque méthode dans un mêmeschéma de segmentation coopératif afin d’aboutir à un résultat de segmentation fiable. Les tests ont été effectués sur unorthophotoplan contenant 100 toitures de complexité variée et évaluées avec le critère de VINET utilisant une segmentationde référence afin de prouver la robustesse et la fiabilité de l’approche proposée. Une étape de comparaison permettantde situer les résultats obtenus via notre approche proposée par rapport à ceux obtenus pas les principales méthodes desegmentation de la littérature est finalement effectuée. / The work presented in this thesis is developed in a global approach that consists in recognizing roofs extracted from aerialimages using a knowledge database, and bending out 3D models automatically generated from geographical data. Themain step presented in this thesis consists in segmenting roof images in different regions of interest in order to provideseveral measures of roofs (section of roofs, chimneys, roof light, etc).The method aimed at achieving this goal is composed of three principal steps: (i) A simplification step that consists insimplifying the image with an appropriate (optimized for the application) couple of invariant/gradient. For that, several testshave been performed to choose a suitable colorimetric invariant among a set of 24 invariants and define the best gradientamong 14 gradients (eight gray level gradients and six color gradients) of the literature. (ii) The second step is composedof two main treatments: On the one hand, the preliminary orthophotoplan segmentation is produced using the watershedregions applied on the simplified image. An efficient region merging strategy is then applied in order to deal with theover-segmentation problem. The regions merging procedure includes a merging criteria adapted to the orthophotoplanparticularities. In order to calculate one of the merging criteria, a 2D modeling of roof ridges strategy is proposed. Onthe other hand, the simplified image is segmented by the watershed lines. (iii) The third step consists in integrating bothsegmentation strategies by watershed algorithm into a single cooperative segmentation scheme to achieve satisfactorysegmentation results. Tests have been performed on an orthophotoplan containing 100 roofs with varying complexity andevaluated with VINET criteria using a ground truth image segmentation. Comparison results with five popular segmentationtechniques of the literature demonstrates the effectiveness and the reliability of the proposed approach.