Dans l’air intérieur, de nombreux composés organiques volatils sont présents, parmi lesquels le formaldéhyde, composé cancérogène. Sa présence dans l’air intérieur s’explique par son utilisation abondante dans les matériaux d’ameublement et de décoration. L’objectif est de concevoir un procédé d’épuration, propre, sûr et capable d’éliminer le formaldéhyde de l’air intérieur. Le choix s’est tourné vers un épurateur d’air autonome. Afin de protéger les utilisateurs, le dispositif doit piéger et dégrader complètement les polluants de l’air sans émettre de sous-produits. L’absorption a été choisie comme méthode de piégeage et la photocatalyse comme technique de dégradation. L’épurateur pilote couplant absorption et photocatalyse a été testé en laboratoire et un modèle a été construit pour prédire son efficacité à dégrader en continu le formaldéhyde. L’épurateur dimensionné pour une situation réelle se révèle avoir un encombrement réduit, compatible avec son installation dans un bureau / In indoor air, many volatile organic compounds are present, including formaldehyde. The presence of this carcinogenic compound in indoor air is due to its abundant use in furniture and decoration materials. The objective of this work is to design a purification device, clean, safe and capable of removing formaldehyde from indoor air. The choice turned to a stand-alone air purifier. To protect users, the device must trap and completely degrade air pollutants without emitting by-products. Absorption was chosen as trapping method and photocatalysis as degradation technique. The cleaner coupling absorption and photocatalysis has been tested in the laboratory and a model was built to predict its efficiency to continuously degrade formaldehyde. The purifier designed for a real situation appears to have a small volume. An efficient, compact, quiet and attractively designed device is an advantage for this air purification solution is accepted and adopted by users

Many of the bands in the vapor-phase far-ultraviolet absorption spectra of simple molecules can often be fit to mathematical progressions referred to as molecular Rydberg series. The name Rydberg arises from the similarity between the Rydberg formula for the atomic hydrogen spectrum and the formulae for the progressions found in molecular spectra. The theories of molecular Rydberg transitions and states are discussed in terms of the inferences that have been made in the past from the available spectral data. The dipole moment changes (ca. 0.4 Debye units) from the ground state to all of the Rydberg states studied were found to be smaller than changes typically found in transitions of charge-transfer nature (ca. 1 Debye unit). The implication is that the Rydberg transitions are fairly localized. The changes in polarizability are on the order of 6 x 10⁻²⁴ cm³ and are assumed to be increases over those of the ground state.

The aim of this diploma thesis is to study the optical properties of new -conjugated molecules based on 1,4-di(4'-N, N-diphenylaminostyryl)benzene and their potential application in advanced imaging techniques of biological specimens, the so-called multiphoton microscopy. The thesis focuses mainly on the characterization of their optical properties and the determination of their two-photon absorption cross-section using a unique laser equipment. Furthermore, a suitable methodology for the preparation of nanoparticles from these molecules, their characterization and stability are also developed. The thesis also investigates the influence of structure on the optical properties of these molecules. The relation between the length of the conjugated system and the presence of substituents on the backbone has been shown for the optical properties of the molecules in the solvent, the position and shape of the two-photon absorption spectrum and the value of two-photon absorption cross-section. It has been shown that this substance retains its unique fluorescent properties even in the form of nanoparticles and therefore appears to be a suitable candidate for the observation of biological specimens using multiphoton fluorescence microscopy. The work contributes to the knowledge base for the design of the chemical structure of molecules with desired properties.

This diploma work aims to evaluate the functional connection of the cogeneration unit with an internal combustion engine and an absorption heat pump to increase the heating effect of the cogeneration. The aim of this work is to design a functional system and evaluate it from the technical - economic terms. In the introduction of the theoretical work the applied cogeneration technologies used in combined heat and power production are presented. Then there is described the principle of heat pumps, their basic components and theoretical comparison of compression and absorption heat pumps. In the practical part of this work is for a specific application in the area Technická 2 proposed merger of the cogeneration unit with an internal combustion engine and an absorption heat pump, while detailed design parameters used in absorption heat circulation are set. At the end of this paper there are designed various heat exchangers of applied absorption heat pump. The final part of the work is devoted to technical - economic assessment of applied design. In this assestment three different types of heat pumps are compared: Absorption heat pump with working solution H2O-LiBR, absorption heat pump with working fluids NH3-H2O and compressor heat pump.

Die Nutzung von Riometern (Relative Ionospheric Opacity Meter) zur Messung relativer atmosphärischer Absorption (in dB) ist eine etablierte Methode. Hingegen ist die Messung atmosphärischer Absorption mit absolutkalibrierten Radaren in Form einer Rauschtemperatur eher selten durchgeführt worden. In dieser Arbeit werden die Möglichkeiten einer absoluten Radarkalibrierung für ein kommerzielles SKiYMET-System vorgestellt. Die gemessene QDC (Quiet Day Curve, eine Referenzkurve für ungestörte Tage) wird dabei mit Referenzdaten verglichen. Daran wird der Einfluss des Antennenmusters auf die QDC verdeutlicht und quantitativ dargestellt. Die erreichte Genauigkeit beträgt dabei ungefähr 600 K. Die kontinuierliche und stabile Beobachtung erlaubt es, die Kopplung der Ionosphäre mit der solaren Aktivität zu untersuchen, ohne den normalen Betrieb zur Meteoranalyse zu unterbrechen. / The observation of relative atmospheric absorption (in dB) using Riometers (Relative Ionospheric Opacity Meter) is a well established method. However, the measurement of atmospheric absorption as a noise temperature with absolutely calibrated radars has rarely been realized. This work demonstrates the possibilities to perform an absolute radar calibration for standard SKiYMET meteor radars. The measured QDC (Quiet Day Curve) and the comparison to a reference QDC illustrates the capability to quantify the effect of the antenna pattern. The achieved accuracy for a QDC is approximately 600 K. The high stability of the observation during normal meteor mode allows also to investigate the ionospheric response caused by the coupling of the solar activity.

<p>Infrared intersubband absorption of III-nitride materials has been studied rigorously due to its broad potential applications into optoelectronic devices. III-nitrides have advantages of large conduction band offset, large longitudinal-optical phonon energy, and fast intersubband relaxation time. These special characteristics make nitrides promising materials for intersubband devices in the near-infrared range. However, the existence of challenges from these materials delays the progress towards the realization of high performance nitride intersubband devices. In this document, we discuss the challenges of III-nitrides and our efforts towards high intersubband transitions strength of different nitrides, in particular non-polar m-plane AlGaN/GaN, non-polar m-plane near strain-balanced (In)AlGaN/InGaN, and polar lattice-matched InAlN/GaN. Samples are characterized by multiple methods including atomic force microscopy, high-resolution x-ray diffraction, high-resolution (scanning) transmission electron microscopy, and Fourier transform infrared spectroscopy.</p> <p>Polar c-plane AlGaN/GaN exhibits good agreement between experimental and predicted results for the intersubband transition energy. However, the lattice strain between layers caused by the lattice mismatch between materials leads to a large number of defects, affecting the vertical transport and resulting in low-quality devices. Lattice-matched InAlN/GaN was suggested as an alternative to eliminate this lattice strain, thus providing a better quality material for devices. We discuss the challenges of growing homogeneous InAlN alloys that persist after exploring a wide range of growth conditions. Additionally, the non-polar mplane AlGaN/GaN is also being investigated. Low Al-composition m-plane AlGaN/GaN experimental intersubband absorption shows good agreement with the theoretical results. As the Al composition exceeds 60%, however, the m-plane AlGaN alloy becomes kinetically unstable during plasma-assisted molecular beam epitaxy growth, resulting in unique nanostructures that affect the intersubband transition energy and linewidth. For the first time, we reported the ISBA energy of near strain-balanced non-polar m-plane (In)AlGaN/InGaN heterostructures in the mid-infrared range with narrow linewidths comparable to tdth-half-max published in the literature for non-polar m-plane AlGaN/GaN superlattices. Additionally, we propose polar near lattice-matched Sc0.15Al0.85N/GaN as an alternative to c-plane lattice-matched InAlN/GaN. </p>

Mes travaux de thèses portent sur l'étude de la photodetection infrarouge par processus d'absorption à deux photons non-dégénérés (NDTPA) dans des diodes nanostructurées à grand gap. Ce concept innovant permet en effet la détection infrarouge sans avoir recours aux systèmes de refroidissement du détecteur.Dans un premier temps, je recherche les paramètres clefs de cette étude. Pour commencer, j'étudie, théoriquement et expérimentalement, la compétition entre deux processus d'absorption sub-gap : l'absorption à deux photons, qui est un processus non linéaire du troisième ordre, et l'absorption linéaire sub-gap sur les défauts du semiconducteur (PASRH). La faible efficacité du NDTPA m'a ensuite amené à étudier des nanostructures capables de concentrer le champs lumineux dans une jonction en semiconducteur, donc d'augmenter l'efficacité absorption.Dans un second temps, je présente la conception, la fabrication en salle blanche et la caractérisation de deux générations de diodes nanostructurées pour la détection infrarouge par NDTPA. Les diodes de première génération sont des jonctions PIN en InP dont l'électrode supérieure nanostructurée est mono-résonante à 3.39 µm. J'ai vérifié leurs propriétés électrique et optique sur un banc dédié que j'ai monté. Finalement, je démontre la détection d'un flux infrarouge à température ambiante par NDTPA et avec un rapport signal sur bruit de 15. Une caractérisation du photocourant mesuré permet de déterminer que la nanostructure permet un gain de 24 sur la génération de photocourant par NDTPA.Après une analyse de cette étude et de ses difficulté, je propose et fabrique une seconde génération de diode nanostructurée résonante aux longueurs d'onde de pompe et de signal. Ce nouveau design permet d'atteindre des gains théorique de l'ordre de 1500 sur la génération de photocourant par NDTPA tout en limitant le photocourant parasite généré par PASRH.Finalement, dans un dernier volet, je présente un nouveau type de nano résonateurs à haut facteur de qualité utilisé dans le cadre des diodes de seconde génération. J'en présente un modèle analytique ainsi que ses principales propriétés. / My thesis work is focused on infrared photodetection through non-degenerated two photons absorption (NDTPA) in a nanostructured large band-gap diode. This innovative concept is an alternative scheme for infrared detection at high operating temperatures.In a first step I will search for the key parameters of this study. I start by studying, theoretically and experimentally, the competition between two sub-gap absorption processes : the NDTPA, which is a non-linear phenomena of the third order, and the linear sub-bandgap absorption on the semiconductors defects (PASRH). Steered by the intrinsically low absorption efficiency of NDTPA, I studied the amplification of photocurrent generation through the fields concentration induced by a nanostructure.In a second time, I present the computed design, the fabrication inside a clean-room and the characterisation of two generations of nanostructured diodes. The first generation diodes are PIN junctions made of InP whose nanostructured top electrodes are mono-resonant at the signal wavelength (3.39 µm). I checked their electrical and optical properties on a dedicated bench that I designed. Finaly I demonstrate an infrared detection at room temperature through NDTPA with a signal-to-noise ratio above 15. A gain of 24 on the generation of photocurrent is attributed to the nanostructure.After an analysis of this first study, I designed and fabricated a second generation of nanostructured diode which are resonant at both the signal and the pump wavelength. This new design can theoretically achieve a gain around 1500 on the generated photocurrent while keeping the parasite PASRH photocurrent under control.Finally in a last part, I study a new high-quality factor nano-resonator which has been used in the design of the second generations diodes. I present an analytical model as well as their principals properties.

Lorsqu’elle est excitée par une onde ultrasonore, une bulle d’air oscille. Les mouvementsl’interface eau-air entrainent un déplacement local du fluide hôte qui devient lesiège de la propagation d’une onde diffusée. Ce mécanisme très simple est fidèlementdécrit par le formalisme de Rayleigh-Plesset datant du début du siècle dernier. Abasse fréquence, au voisinage de la résonance de Minnaert, les oscillations de la bullepeuvent devenir particulièrement amples et la diffusion extrêmement efficace. Dansun environnement réaliste, les bulles sont présentes en grand nombre et la descriptionse complique sensiblement puisque la propagation résulte de l’interférence entre uneinfinité de séquences de diffusion.Au cours de cette thèse, nous introduirons les modèles de milieux effectifs quipermettent de prédire le comportement de fluides bulleux désordonnés. Après avoirété confrontées aux résultats issus de la simulation numérique, ces théories effectivesnous permettront de concevoir des matériaux désordonnés aux propriétés étonnantescomme la superfocalisation ou la réfraction négative.Nous envisagerons également l’étude d’arrangements cristallins et verrons que lapériodicité induit des modifications sensibles dans le comportement du milieu tout enconstituant un levier de contrôle efficace.Enfin, la bulle est susceptible de se mouvoir et, par conséquent, de ressentir desforces de pression de radiation. En particulier, Nous verrons comment la force deBjerknes secondaire, issue du champ diffusé par une bulle vers l’une de ses voisines,peut être exploitée afin de manipuler une ou plusieurs bulles mobiles au voisinaged’une ou plusieurs bulles piégées. / A bubble undergoing an acoustic wave is likely to oscillate. The displacement of theair-fluid interface generates a local compression of the outer fluid where a scatteredwave is thus created. This very simple mechanism has been successfully described bythe famous Rayleigh-Plesset formula derived at the beginning of the previous century.At low frequencies, the resonant behavior (Minnaert) is responsible for a strongenhancement of the oscillations of the bubble which thus becomes a very efficientscatterer. In a realistic media, bubbles are not isolated. The interferences occurringbetween an infinity of scattering sequences make the description of the propagation alot harder to achieve.In this thesis, we introduce the effective theories that are classically adopted todescribe random bubbly liquids. After being compared to our numerical results, thesetheories are used in order to design bubbly materials featuring some interesting propertiessuch as superfocusing or negative refraction.The case of periodic assembly is addressed as well for both a simple square latticebubble raft and a cubic centered faces bi-periodic crystal. We show that the periodicityinduces an explicit modification in the dispersion of the medium and offers asimple tunable parameter.At last, we focus on the possibility for the bubble to move inside the host fluid andwhich is thus likely to experience an acoustic radiation pressure called Bjerknes force.We show how the secondary Bjerknes force, resulting from the wave scattered by abubble toward its neighbors, can be exploited in order to manipulate one or severalfree bubble flowing near one or several trapped bubbles.

L’obésité et le surpoids sont aujourd’hui des problèmes de santé majeurs au niveau mondial touchant près de 1,9 milliard d’adultes. Cet état physiologique se définit comme une accumulation excessive de masse grasse dans l’organisme avec des conséquences néfastes sur la santé. L’obésité tient son origine d’un déséquilibre de la balance énergétique résultant d’une consommation excessive de calories par rapport aux dépenses énergétiques. En accord avec cette idée, les lipides alimentaires représentent les macronutriments les plus caloriques dont la biodisponibilité est assurée par l’intestin. L’accumulation excessive de ces lipides dans les tissus tel que le foie, le tissu adipeux et les vaisseaux sanguins déclenche une inflammation bas-bruit. Cette inflammation bas-bruit est souvent associée à une augmentation modérée de l’endotoxémie métabolique, c’est-à-dire du taux sanguin des lipopolysaccharides bactériens provenant du microbiote intestinal.Dans un premier temps, les travaux de cette thèse avaient pour objectif de définir la contribution de l’intestin dans la mise en place de cette endotoxémie métabolique à travers le rôle du récepteur CD36. En effet, il est montré que ce récepteur participe à la biodisponibilité des lipides en favorisant leur absorption et la formation des chylomicrons qui véhiculent les lipopolysaccharides. Les données obtenues ont permis de montrer que CD36 participe aux situations d’endotoxémie métabolique en régulant l’écologie microbienne du site d’absorption des lipides alimentaires.Dans un second temps, ces travaux se sont intéressés à la contribution de la réponse inflammatoire dans les mécanismes d’absorption des lipides alimentaires au travers du rôle de l’inflammasome NLRP3. Ils ont permis de montrer que cet inflammasome participe à la digestion et à l’absorption des lipides alimentaires lors d’un régime hyperlipidique obésogène.L’ensemble de ces données permet d’établir le rôle majeur de l’intestin dans la mise en place de l’endotoxémie et des processus inflammatoires conduisant à une situation d’obésité. De plus, le récepteur CD36 et l’inflammasome NLRP3 pourrait constituer des cibles thérapeutiques de choix pour limiter la mise en place de cet état physiologique. / Nowadays, obesity and overweight are major health problems affecting nearly 1.9 billion adults. This physiological state is defined as an excessive accumulation of fat mass in the body with harmful consequences on health. Obesity is caused by a disequilibrium in the energy balance resulting from an excessive calorie consumption in relation to the energy expenditure. According to this concept, dietary fats represent the most caloric macronutrients whose bioavailability is ensured by the intestine. Excessive accumulation of these lipids in tissues such as liver, adipose tissue and blood vessels triggers low-grade inflammation. This low-grade inflammation is often associated with a moderate increase in metabolic endotoxemia, i.e. an increase in the blood level of bacterial lipopolysaccharides coming from the intestinal microbiota.First, the aim of this thesis was to elucidate the contribution of the intestine to the development of the metabolic endotoxemia through the role of the CD36 receptor. Indeed, this receptor participates in the bioavailability of dietary lipids by promoting their absorption and the formation of chylomicrons able to carry the lipopolysaccharides. The data obtained showed that CD36 could participates in metabolic endotoxemia situations by regulating the microbial ecology of the food lipid absorption site.In a second step, this work focused on the contribution of the inflammatory response to the absorption mechanism of dietary lipids through the role of the NLRP3 inflammasome. It showed that this inflammasome is involved in the digestion and absorption of dietary lipids in high-fat diet-induced obesity.The data obtained allow to establish the major role of the intestine in the development of endotoxemia and inflammation during the development of obesity. In addition, the CD36 receptor and the NLRP3 inflammasome may be therapeutic targets to limit the development of this physiological condition.

Syftet med detta examensarbete var att utveckla en helt bio-baserad vatten- och smutsavstötande ytbehandling för trä med ambitionen att ersätta en icke bio-baserad referens produkt på marknaden. Flera emulsioner med oljor och vaxer har framställts och analyserats utefter emulsionernas stabilitet och kvalitet. Flera av dessa emulsioners vattenabsorption, kontaktvinkel, pH värde vid ytan och åldrande i utomhusmiljö testades också efter att olika typer av trä behandlats med formuleringarna. En del av formuleringarna verkade ge liknande vattenabsorption som referensen på de olika typerna av trä med undantag för trä typ 4 där de bio-baserade formuleringarna presterade bättre än referensen. Vidare bildade även de bio-baserade formuleringarna en mindre gul och sträv yta jämfört med referensen och de genomgick dessutom en mindre fysisk förändring efter placering utomhus. Dock var stabiliteten för de bio-baserade emulsionerna sämre än för referensen. Dessutom resulterade de bio-baserade formuleringarna till en mindre pH sänkning på trä typ 3 med alkaliskt. / The aim of this thesis project was to develop a fully bio-based water and dirt repellent wood coating with the ambition to replace the current non-bio-based reference product on the market. Several wax and oil emulsions were made and analyzed in terms of emulsion quality and stability. Several formulations were also tested on different types of wood in terms of water absorption, weathering, surface pH and contact angle. Some formulations seam to give similar water absorption as the reference, the not bio-based product and performs similar on different types of wood with an exception on Wood type 4 where the bio-based formulations performs better than the current reference product. Secondly the bio-based formulations form a less yellow and rough coating compared to the current reference product. According to the weathering test the bio-based formulations seams to perform better. However, the stability of the bio-based formulation is not as good as the current reference product. Also, the developed bio-based conceptual formulations exhibited limited pH lowering on Wood type 3 with alkaline pH.