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Photo-thermal control of surface plasmon mode propagation at telecom wavelengths / Le contrôle photo-thermique de la propagation du mode plasmon de surface aux longueurs d'onde télécomKaya, Serkan 17 October 2016 (has links)
Les plasmons-polaritons de surface (PPS) font figure de plateforme polyvalente très promet- teuse pour le guidage des ondes électromagnétiques à l’échelle nanométrique. Dans ce contexte, le contrôle dynamique de la propagation PPS est d’une importance capitale. Le contrôle actif des dispositifs plasmoniques a souvent été réalisé jusqu’à présent par le biais d’un effet thermo-optique (TO). Toutefois dans la majorité des cas considérés, l’effet thermo-optique résulte d’une modification des propriétés d’un matériaux diélectrique en contact avec le métal supportant le mode plasmon. Ainsi, le rôle des propriétés thermo-optiques du métal lui-même a rarement été analysé aux fréquences télécom dans le cadre d’applications plasmoniques. L’objectif principal de cette thèse est donc d’analyser en détail l’impact des propriétés thermo- optiques des métaux sur différents modes PPS aux longueurs d’ondes télécom. En premier lieu, nous considérons la modulation photo-thermique d’un mode plasmon supporté par un film mince d’or se propageant à l’interface "or/air". Nous démontrons tout d’abord la modulation de la propagation des modes PPS induite par la dépendance des pertes ohmiques de l’or à la température du film mince. Le contrôle de la température du film est obtenu par un effet photo-thermique en régime continu modulé. Les mesures expérimentales de la pro- fondeur de modulation de l’intensité des modes PPS combinées à la simulation numérique de la distribution de température le long du film d’or nous permettent de remonter aux coefficients thermo-optiques de l’or aux fréquences télécoms. Dans un second temps, nous considérons le contrôle thermo-optique de modes plasmons dont le confinement spatial (et donc l’indice effectif) est supérieur à ceux des modes de films. Les modes considérés dans cette seconde étude sont connus sous le nom de "polymer- loaded surface plasmon waveguides (PLSPPWs)". Ces modes présentent un confinement latéral induit par l’indice de réfraction du ruban de polymère déposés sur le film métallique et un confinement vertical résultant de leur nature plasmonique. L’excitation photo-thermique de ces guides plasmoniques dans un régime nano-seconde nous permet de mettre en évidence la dynamique thermo-optique du métal aux temps courts (<1ns) et du polymère aux temps plus longs (<1µs). La même démarche appliquée à un micro-résonateur plasmonique en anneau révèle les temps caractéristiques de la dynamique de diffusion de la chaleur dans le polymère à l’échelle de quelques dizaines de nanomètres. Sur la base de ces expériences, nous suggérons un design de dispositifs plasmoniques thermo-optique dont la bande passante est de l’ordre du megahertz, un ordre de grandeur au-dessus des systèmes thermo-optiques traditionnels. Enfin, nous présentons la modulation photo-thermique de la propagation PPS le long de nanofils d’or fabriqués par lithographie électronique supportant des modes plasmons très confinés aux longueurs d’onde télécom. La transmission d’un signal télécom à 10 Gbit/s est tout d’abord démontrée afin d’établir sans ambiguïté la pertinence de tels guides d’ondes miniatures pour la transmission d’informations à très courtes échelles. Enfin, nous mettons en évidence la modulation photo-thermique de la propagation de tels modes. En particulier, nous investiguons l’influence sur la profondeur de modulation de la polarisation du faisceau pompe relativement à l’orientation des nanofils. Cet effet de polarisation s’explique par une absorption exaltée si la polarisation du faisceau pompe est orientée perpendiculairement à l’axe du nanofil. L’exaltation résulte de l’excitation d’un mode plasmon local selon l’axe transverse du nanofil. / Surface plasmon polaritons (SPPs) is the promising versatile platform proposed for guiding electromagnetic waves at nanoscale dimensions. In this context dynamic control of SPPs prop- agation is of paramount importance. Thermo-optical (TO) effect is considered as an efficient technique for performing active control of plasmonic devices. Among the thermo-optical based plasmonic devices demonstrated so far TO coefficient is dominantly provided by a dielectric material on top of the metal sustaining the SPP mode, however, the role of TO properties of the metal has been rarely investigated for plasmonic applications especially at the telecom frequency ranges. Therefore, the aim of this thesis is to investigate in detail the impact of thermo-optical properties of metals onto various SPP modes at telecom wavelengths.First, we report on photo-thermal modulation of thin film SPP mode traveling at gold/air interface excited at telecom wavelengths. We start by investigating the photo-thermally in- duced modulation of SPPs propagation mediated by the temperature dependent ohmic losses in the gold film. Then we extract the thermo-plasmonic coefficient of the SPP mode from the accurately measured SPPs signal depth of modulation by which we could compute the thermo-optical coefficients (TOCs) of gold at telecom wavelength. Lastly, we demonstrate a pulsed photo-thermal excitation of the SPPs in the nanosecond regime.Secondly, we investigate the thermo-optical dynamics of polymer loaded surface plasmon waveguide (PLSPPW) based devices photo-thermally excited in the nanosecond regime. First, we demonstrate thermo-absorption of PLSPPW modes mediated by the temperature-dependent ohmic losses of the metal and the thermally controlled field distribution of the plasmon mode within the metal. Next, we consider the thermo-optical response of a PLSPPW based racetrack shaped resonator coupled to a straight bus waveguide and evaluate the photo-thermal activation through heating and cooling times. We conclude that nanosecond excitation combined to high thermal diffusivity materials opens the way to high speed thermo-optical plasmonic devices.Finally, we report on the photo-thermal modulation of SPPs propagation along litho- graphically fabricated gold nanowires sustaining highly confined plasmonic mode at telecom wavelengths. First, we investigate telecommunication characterization of the nanowires by ap- plying high bit rate signal transmission, 10 Gbit/s, through fiber-to-fiber confocal detection setup. Next, we demonstrate and evaluate the photo-thermal modulation of SPPs propagation along the nanowires where we discuss qualitatively TO effects due to light-induced modula- tions on nanowires and show the impact of the incident beam polarization on the photo-thermal modulation.
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Příspěvek k výzkumu makrostylistických posunů na příkladu románu M. Stavariče v českém překladu / Contribution to the investigation of macro-stylistic shifts, as exemplified by the Czech translation of M. Stavaric's novelŽáková, Radka January 2017 (has links)
1 ABSTRACT The goal of this diploma thesis is a complex analysis of the translation of the novel stillborn written by Michael Stavarič, translated into Czech by Radka Denemarková as Mrtvorozená Eliška Frankensteinová. The theoretical part presents the concept of translation norms (a starting point for reconstructing the translation method chosen), Skopos theory, the theory of metatexts, phenomena pertaining to self-translation (the new concept of "self-non-translation", i.e. the decision of an author-translator not to translate their own work) and Popovič's (1975, 1983) "typology of stylistic shifts and changes in translation" as a basic tool for the subsequent micro-textual contrastive analysis of selected parts of the translation. In the empirical part, the author and his work are briefly introduced, the thesis then provides a narratological analysis of the original; in the following part the translator and her work are introduced. This is followed by a description of the translation's reception in the Czech cultural environment based on an analysis of the available literary reviews ("epitexts") of the translation; these results are compared with the results of the analysis of the German literary reviews of the original. Additional information came from interviews with the author and the translator. A...
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Perceptions of staff and students concerning support offered to students the MA (Social Behaviour Studies in HIV/AIDS) at the University of South AfricaMatee, Marie 06 1900 (has links)
The MA Social Behaviour Studies in HIV and AIDS as a postgraduate degree
requires students to work and conduct research independently. The purpose of
the study was to gauge the perceptions, attitudes and experiences of second
year students and key personnel concerning student support. A mixed methods
research design was used. It was found that students and staff regarded support
in a positive light, although concerns about insufficient resources were
expressed. Students expressed needs for specific academic and research
support. Staff tended to romanticise the reasons for students enrolling for the
degree. Possible conflicting expectations of the degree and the amount and type
of support offered were found between the staff and the students and also among
various staff members. / Social Work / M.A. (Social Behaviour Studies in HIV-AIDS)
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Programovn mikrokontrol©r c2000 v programu MATLAB/Simulink / MATLAB/Simulink Model Based Design Using C2000 Microcontrollersoupal, Ondej January 2020 (has links)
The aim of this thesis is to explore possibilities of rapid control prototyping, describe the concept of creating the software application in MATLAB/Simulink environment with use for development kit Texas instruments LaunchPad and create an application for DC and induction motor control in this environment. This work describes the application for unipolar/bipolar control H-Bridge of power converter for DC motor, measurement of output currents, speed and its displaying in real time using serial control interface. This thesis also desribes scalar and vector control of induction motor. All software applications with measurements are created in MATLAB/Simulink and attached to the thesis.
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Srovnání nákladů rodinných domů s nosnou konstrukcí z tenkostěnných ocelových profilů / Cost comparison of family houses with structures of thin-walled steel profilesPozděnová, Barbora January 2015 (has links)
The aim of this thesis is to find the best option of the building technology for a house. The thesis is divided into two sections – theoretical and practical. The theoretical section consists of three parts. The first part deals with theory of costs and pricing. Second part specifies types of the budgeting used in Czech Republic and the last part is focused on description of the selected construction systems used for building a house. Second section deals with description and the layout of the house, for which three budgets are set with a respect to the used option of the construction system. Furthermore, a comparison of the technical parameters as well as the costs analysis according to the TSKP is made. Finally, the optimal variant is selected with respect to the price and technical properties.
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Optimalizace chlazení RD využívajícího zemní vrty / Optimization of cooling of a family house by using a geothermal systemBuchta, Jan January 2015 (has links)
The master’s thesis deals with optimization of cooling system of family house using borehole heat exchanger as a single cooling source. In the experimental part of the thesis was carried out long-term mearurements. The main part of the master’s thesis is the development and verification mathematical and physical model of thermal behavior chilled room. The result are computer simulations and evaluation of individual scenarios and design requirements for a potential optimization of measurement and control system. The theoretical part generally deals with radiant cooling systems.
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Natural gas storage level forecasting using temperature dataSundin, Daniel January 2020 (has links)
Even though the theory of storage is historically a popular view to explain commodity futures prices, many authors focus on the oil price link. Past studies have shown an increased futures price volatility on Mondays and days when natural gas storage levels are released, which could both implicate that storage levels and temperature data are incorporated in the prices. In this thesis, the U.S. natural gas storage level change is studied as a function of the consumption and production. Consumption and production are furthered segmented and separately forecasted by modelling inverse problems that are solved by least squares regression using temperature data and timeseries analysis. The results indicate that each consumer consumption segment is highly dependent of the temperature with R2-values of above 90%. However, modelling each segment completely by time-series analysis proved to be more efficient due to lack of flexibility in the polynomials, lack of used weather stations and seasonal patterns in addition to the temperatures. Although the forecasting models could not beat analysts’ consensus estimates, these present natural gas storage level drivers and can thus be used to incorporate temperature forecasts when estimating futures prices.
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Mise au point d’un nouveau modèle d’organoïde cérébral humain pour l’étude des mécanismes d’interaction de la protéine prion et de l’amyloïde β / Set Up of a New Human Cerebral Organoid Model to Study the Interaction Mechanisms of Prion and β Amyloid ProteinsPavoni, Serena 13 December 2017 (has links)
Les mécanismes de type prion sont désormais reconnus comme sous-tendant la plupart des maladies neurodégénératives humaines, avec en premier lieu la maladie d’Alzheimer (MA) au niveau de ses 2 marqueurs spécifiques, l’amyloïde β (Aβ à l’origine de l’hypothèse étiopathogénique de la cascade amyloïde) et la protéine Tau phosphorylée. Par ailleurs la protéine du prion (PrPC) est décrite comme interagissant à de multiples niveaux avec le métabolisme de l’Aβ sans que les mécanismes physiopathologiques sous-jacents n’aient pu être expliqués. Pour sortir de l’impasse actuelle concernant le développement d’approches thérapeutiques efficaces pour la MA, l’industrie pharmaceutique a besoin de modèles expérimentaux innovants. En effet, à ce jour aucun modèle in vivo, en dépit des progrès réalisés avec les souris transgéniques, n’arrive à refléter la complexité cérébrale humaine ni à mimer une MA clinique. Les cultures in vitro en 2D sont quant à elles très éloignées des situations conduisant à l’accumulation d’agrégats protéiques pathologiques. Le but de notre thèse a été d’utiliser dans le domaine des neurosciences les nouvelles perspectives de recherche ouvertes par les technologies des cellules souches pluripotentes induites (cellules iPS) en développant un modèle de différentiation en 3D pour obtenir des organoïdes cérébraux humains (OC) (mini cerveaux). Leur capacité d’auto-organisation en 3D de tissu neuroectodermique nous a permis de recréer un système complexe mimant différentes structures cérébrales humaines dans lesquelles nous avons pu caractériser les marqueurs attendus. L’étude de l’expression des protéines d’intérêt APP et PrPC pendant la différentiation neurale a permis de caractériser la modulation des niveaux des deux protéines en fonction du temps de culture. Afin d’orienter le modèle vers des mécanismes d’accumulation protéique de type MA, nous avons testé différents inducteurs chimiques dont l’Aftin-5 qui est capable de moduler les voies post-traductionnelles de l’APP. Plusieurs stratégies de traitement ont été adoptées pour induire le clivage de l’APP et la génération d’Aβ. La production des fragments solubles Aβ38, Aβ40, Aβ42 a été mise en évidence par ELISA. Les niveaux générés sont reproductibles et l’augmentation du ratio Aβ42/Aβ40 est cohérente avec les données extrapolées des modèles murins et humains, ce qui a permis de valider notre modèle. Les niveaux d’expression génique et protéique de PrPC et de APP suite au traitement ont été analysés afin de mieux déterminer le rôle de l’interaction entre ces deux facteurs. L’objectif à long terme consiste à améliorer ce modèle, dont les limites actuelles sont notamment l’absence de vascularisation et le niveau de maturation du tissu neural. Le défi majeur dans le cadre de la culture des OC consiste donc à favoriser l’intégration du système vasculaire, et par ailleurs à accélérer le vieillissement in vitro pour l’étude de maladies neurodégénératives. La perspective de pouvoir automatiser le système de culture des OC permet d’envisager l’utilisation de ce modèle à plus grande échelle dans le cadre de test de cytotoxicité et/ou de criblage pharmacologique à haut débit pour identifier de nouvelles molécules thérapeutiques pour la MA. / Prion-like mechanisms are known to underlie most of human neurodegenerative diseases including Alzheimer’s disease (AD), which is characterized by two important pathological markers, β amyloid (or Aβ at the origin of the etiopathogenic amyloid cascade hypothesis) and phosphorylated tau protein. Furthermore, the prion protein (PrPC) interacts at multiple levels with the metabolism of Aβ, by mechanisms which are not well understood. To overcome the current limits in the development of efficient strategies to treat AD, the pharmaceutical industry requires innovative experimental models. However, even if a lot of progress has been achieved by using transgenic mouse models, to date no in vivo model can reflect the complexity of human brain or reproduce a clinical context. 2D in vitro cell culture models are unable to allow the aggregation and accumulation of pathological proteins as observed in vivo. The aim of this study consists in taking advantage of the research prospects offered by induced pluripotent stem cell (iPSCs) in the field of neurosciences. iPSCs can be used to generate 3D models of differentiation also called human cerebral organoids or mini-brains (MBs). Their ability to self-organise in 3D neuroectodermic tissue leds to a complex system that mimics different human cerebral structures in which we were able to characterize the expected markers. The study of the two proteins of interest (APP and PrPC) during neural differentiation has allowed us to follow the modulation of protein expression level occurring during the in vitro development of the human MBs. In order to use this model to reproduce the protein accumulation mechanisms seen in AD, we have tested chemical inductors such as Aftin-5 in order to modulate the APP post-transcriptional pathway towards a pathological outcome. Many strategies of treatment are adopted to lead APP cleavage and Aβ generation. The production of soluble fragments Aβ38, Aβ40, Aβ42 in the supernatant of organoids has been showed using ELISA technique. The levels generated are reproducible and the increase of Aβ42/Aβ40 ratio is consistent with extrapolated data from mouse and human models thus validating our model. Analysis at the gene and protein level has been assessed in order to understand the interaction between PrPC and APP after treatment. The long-term goal consists in improving this model which is notably hampered by the absence of vascularization and the low level of maturation of the neural tissue. The main challenge in MB culture thus consists in the integration of the vascular system, and also in increasing the speed of ageing process in vitro for the study of neurodegenerative diseases. In the long term, the prospect of automating the culture of MBs would allow the use of the system for cytotoxicity testing and/or high throughput screening for the discovery of new drugs for AD.
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Evaluation of machine learning methods for anomaly detection in combined heat and power plantCarls, Fredrik January 2019 (has links)
In the hope to increase the detection rate of faults in combined heat and power plant boilers thus lowering unplanned maintenance three machine learning models are constructed and evaluated. The algorithms; k-Nearest Neighbor, One-Class Support Vector Machine, and Auto-encoder have a proven track record in research for anomaly detection, but are relatively unexplored for industrial applications such as this one due to the difficulty in collecting non-artificial labeled data in the field.The baseline versions of the k-Nearest Neighbor and Auto-encoder performed very similarly. Nevertheless, the Auto-encoder was slightly better and reached an area under the precision-recall curve (AUPRC) of 0.966 and 0.615 on the trainingand test period, respectively. However, no sufficiently good results were reached with the One-Class Support Vector Machine. The Auto-encoder was made more sophisticated to see how much performance could be increased. It was found that the AUPRC could be increased to 0.987 and 0.801 on the trainingand test period, respectively. Additionally, the model was able to detect and generate one alarm for each incident period that occurred under the test period.The conclusion is that ML can successfully be utilized to detect faults at an earlier stage and potentially circumvent otherwise costly unplanned maintenance. Nevertheless, there is still a lot of room for improvements in the model and the collection of the data. / I hopp om att öka identifieringsgraden av störningar i kraftvärmepannor och därigenom minska oplanerat underhåll konstrueras och evalueras tre maskininlärningsmodeller.Algoritmerna; k-Nearest Neighbor, One-Class Support Vector Machine, och Autoencoder har bevisad framgång inom forskning av anomalidetektion, men är relativt outforskade för industriella applikationer som denna på grund av svårigheten att samla in icke-artificiell uppmärkt data inom området.Grundversionerna av k-Nearest Neighbor och Auto-encoder presterade nästan likvärdigt. Dock var Auto-encoder-modellen lite bättre och nådde ett AUPRC-värde av 0.966 respektive 0.615 på träningsoch testperioden. Inget tillräckligt bra resultat nåddes med One-Class Support Vector Machine. Auto-encoder-modellen gjordes mer sofistikerad för att se hur mycket prestandan kunde ökas. Det visade sig att AUPRC-värdet kunde ökas till 0.987 respektive 0.801 under träningsoch testperioden. Dessutom lyckades modellen identifiera och generera ett larm vardera för alla incidenter under testperioden. Slutsatsen är att ML framgångsrikt kan användas för att identifiera störningar iett tidigare skede och därigenom potentiellt kringgå i annat fall dyra oplanerade underhåll. Emellertid finns det fortfarande mycket utrymme för förbättringar av modellen samt inom insamlingen av data.
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Chain Conformation and Nano-Patterning of Polymer Brushes Prepared By Surface-Initiated Atom Transfer Radical PolymerizationGao, Xiang 09 1900 (has links)
<p> Over the past decade, the development of surface-initiated living polymerization methods has brought a breakthrough to surface modification owing to their control ability. Surface-initiated atom transfer radical polymerization (si-ATRP), as the most popular one, has been widely employed to give novel polymer structures and functionalities to various surfaces for the purposes of tailoring surface properties, introducing new functions, or preparing so-called "smart surfaces", which can respond to external stimuli such as solvent type, pH, temperature, electric and magnetic fields etc. In this thesis, the mechanistic study of the si-ATRP was first carried out through modeling to gain good understanding of si-ATRP. Si-ATRP was then employed to prepare different types of polymer brushes to produce "smart surfaces". </p>
<p> The kinetic model was developed using the method of moment. Combined with experimental data, a quantitative analysis was carried out for the si-ATRP mechanism. All information of grafted polymer chains, including active chain concentration, radical concentration, chain length, polydispersity, was illustrated. A new radical termination mechanism, termed as migration-termination, was proposed for si-ATRP. </p>
<p> Si-ATRP was then employed to graft poly(oligo(ethylene glycol) methacrylate) (POEGMA) block poly(methyl methacrylate) (PMMA) brushes on silicon wafer surfaces. Simple solvent treatment gave nanoscale patterns via the phase segregation of POEGMA and PMMA segments. Various patterns including spherical aggregates, wormlike aggregates, stripe patterns, perforated layers and complete overlayers, were obtained by adjusting the upper block layer thickness. Furthermore, these nanopatterns had a unique stimuli-responsive property, i.e., switching between different morphologies reversibly after being treated with selective solvents. </p> <p> POEGMA-block-poly(2-(methacryloyloxy)ethyl trimethylammonium chloride) (PMETAC) brushes, having two hydrophilic segments, were synthesized by si-ATRP method. A variety of nanopatterns and their stimuli-responsive ability were observed. The adsorption behaviors of fibrinogen on these patterns were thoroughly studied by ellipsometry, water contact angel measurement, AFM and radio labelling method. </p> <p>
A novel thermo-responsive copolymer, poly(2-(2-methoxyethoxy)ethyl methacrylate -co-oligo(ethylene glycol) methacrylate) (P(ME02MA-co-OEGMA)), was also grafted onto silicon wafers. Its thermo-responsive behavior and chain conformation in aqueous solution were studied by neutron reflectometry (NR). Both extended and collapsed brushes exhibited good protein adsorption resistance. </p> / Thesis / Doctor of Philosophy (PhD)
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