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Estudo das propriedades ópticas e eletro-ópticas de filmes de carbono amorfo tipo diamante - DLC. / Study of optical and electro-optical properties of diamond-like carbon films - DLC.Vinícius Zacarias Rizzo 18 October 2010 (has links)
Neste trabalho foram estudadas as características elétricas e ópticas de filmes de carbono tipo diamante (DLC Diamond-Like Carbon) depositados em um sistema de sputtering RF magnetron reativo em substratos de silício e vidro. Foram depositadas amostras em condições de processo distintas em cada tipo de substrato, sendo duas condições de pressão (5 mTorr e 10 mTorr) e para cada uma, quatro condições de potência de RF (100 W, 150 W, 200 W e 250 W). Os filmes depositados foram submetidos às seguintes técnicas de caracterização: perfilometria, para obtenção da espessura dos filmes e com isso a taxa de deposição; elipsometria, para obtenção do índice de refração; obtenção de curvas I-V, para obtenção da resistividade elétrica e cálculo do ganho de foto corrente, e da curva C-V de alta frequência, para cálculo da constante dielétrica dos filmes; transmitância óptica, para o cálculo do gap óptico através do método de Tauc; fotoluminescência, para determinar a emissão característica deste gap e espectroscopia de infravermelho por transformada de Fourier (FTIR), para se observar os tipos de ligações presentes no filme e calcular a relação entre hibridizações sp3 e sp2 entre átomos de carbono e hidrogênio no filme. As variações de algumas características dos filmes de DLC com os parâmetros de processo são apresentadas e comparadas. De acordo com as características dos filmes obtidos neste trabalho, com a variação dos parâmetros de processo, é possível sua aplicação como dielétrico de campo, por apresentarem baixa constante dielétrica, sendo o valor mais baixo obtido igual a 3,4; como material dielétrico de porta considerando os filmes com alta constante dielétrica, chegando a 6,7; como material para cobertura, devido à alta uniformidade (até 95%); e, o que foi mais explorado neste trabalho, para aplicações como sensores foto sensíveis, sendo que o maior ganho de foto corrente obtido foi 67 vezes. A possibilidade de produção de filmes de DLC com diferentes propriedades através da variação das condições de processo mostra sua versatilidade para uso em diferentes aplicações. / In this work it was studied electrical and optical characteristics of diamond-like carbon (DLC) films deposited in a reactive RF magnetron sputtering system on silicon and glass substrates. Samples were deposited at different process conditions in each type of substrate at two pressure conditions (5 mTorr and 10 mTorr) and four conditions of RF power (100 W, 150 W, 200 W and 250 W). The DLC films were characterized by the following techniques: high step meter analysis, to obtain the thickness of the films and thus the deposition rate; Ellipsometry to obtain the refractive index; electrical characterization by the I-V curve, to obtain the resistivity and calculate the photo current gain, and high-frequency C-V curve, to calculate the dielectric constant of the films; optical transmittance, to calculate the optical gap by the Tauc method; photoluminescence analysis, to determine the characteristic emission of this gap; Fourier transform infrared spectroscopy (FTIR), to observe the different carbon-hydrogen bonds and calculate its sp3/sp2 hybridizations ratio. The way some characteristics of DLC films vary with the process parameters are presented and compared in this work. According to the characteristics of the DLC films obtained in this work, with the variation of the process parameters it is possible their application as low k dielectric insulators, because of its low dielectric constant, being the lowest obtained value 3.4; as dielectric gate material, reaching 6.7 in the films deposited in this work, as coating material due to its high uniformity (95%), and which was further explored in this work, for applications like photo-sensitive sensors, since it was obtained samples with photo current gain up to 65. The possibility of producing DLC films with different properties by varying process parameters shows its versatility for using in different applications.
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Des acides aminés aux protéines :Etudes en présence de complexes photo réactifs de ruthénium (II)Garnir, Kevin 11 December 2015 (has links)
Le laboratoire de Chimie Organique et Photochimie de l’Université Libre de Bruxelles possède une expertise de longue date dans le développement et l’étude de complexes photo réactifs de ruthénium (II) à base de ligands polyazaaromatiques. Il a été démontré au cours des précédentes décennies que leur intéressante photo-réactivité est engendrée par la présence de ligands polyazaaromatiques fortement π-déficients tels que le 1,4,5,8 tétraazaphénanthrène (TAP). Ceux-ci induisent en effet des propriétés d’oxydo réduction singulières à l’état excité du complexe. Un transfert d’électron photo induit est alors rendu possible, lequel peut conduire à la formation de photo adduit avec la biomolécule.Aujourd’hui, de multiples applications utilisant la formation de ces photo-adduits ont d’ores et déjà été développées dans le cadre de stratégies thérapeutiques visant la guanine composant l’ADN. Au cours du présent travail, nous avons contribué à l’expansion du domaine d’application de tels composés photo-réactifs aux peptides et aux protéines, ces derniers constituant des cibles primordiales dans le cadre des stratégies thérapeutiques actuelles.Les deux premiers chapitres de ce travail sont consacrés à l’étude fondamentale de la photo réaction entre le complexe photo-réactif [Ru(TAP)2phen]2+ et certains acides aminés, jugés comme potentiellement réducteurs, à savoir, le tryptophane, la tyrosine et la cystéine. La démonstration d’un transfert d’électron photo-induit ainsi que la formation de photo-adduit sur base de résultats précédemment obtenus au sein de notre laboratoire seront détaillés, et ce pour les acides aminés seuls en solution mais également lorsqu’ils sont inclus au sein d’une chaine peptidique.Le troisième volet de ce projet reprend les premiers résultats de la photo-réaction potentielle entre le complexe [Ru(TAP)2phen]2+ et une protéine. En effet, pour la première fois, une analyse poussée du milieu photo-réactionnel comprenant un complexe photo-oxydant de RuII ainsi qu’une protéine contenant plusieurs résidus tryptophane est décrite. Cette étude préliminaire a permis de démontrer la nécessité d’un vecteur de reconnaissant pour espérer observer la formation de photo-adduit entre complexe photo-oxydant et protéine.Le dernier chapitre se base sur cette observation pour développer de nouvelles stratégies visant à réguler l’activité enzymatique de protéines kinases grâce à l’illumination de complexes photo-oxydants de RuII. Deux méthodologies ont alors été mises en place. La première utilise un ligand mimétique de la staurosporine, inhibiteur naturel de protéines kinases, afin de permettre une reconnaissance directe de celles-ci par le complexe photo réactif. La seconde consiste à fonctionnaliser le complexe [Ru(TAP)2phen]2+ afin de l’ancrer chimiquement sur un peptide inhibiteur de protéine kinase. La combinaison de ces deux entités, à savoir un centre photo-réactif et un peptide vecteur, a permis l’observation d’une inhibition contrôlée par la lumière de protéines kinases. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished
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Local Biomass Control on the Composition and Reactivity of Particulate Organic Matter in Aquatic EnvironmentsPisani, Olivia 11 May 2011 (has links)
Freshwater ecosystems have been recognized as important components of the global carbon cycle, and the flux of organic matter (OM) from freshwater to marine environments can significantly affect estuarine and coastal productivity. The focus of this study was the assessment of carbon dynamics in two aquatic environments, namely the Florida Everglades and small prairie streams in Kansas, with the aim of characterizing the biogeochemistry of OM. In the Everglades, particulate OM (POM) is mostly found as a layer of flocculent material (“floc”). While floc is believed to be the main energy source driving trophic dynamics in this oligotrophic wetland, not much is known about its biogeochemistry. The objective of this study was to determine the origin/sources of OM in floc using biomarkers and pigment-based chemotaxonomy to assess specific biomass contributions to this material, on a spatial (freshwater marshes vs. mangrove fringe) and seasonal (wet vs. dry) scales. It was found that floc OM is derived from the local vegetation (mainly algal components and macrophyte litter) and its composition is controlled by seasonal drivers of hydrology and local biomass productivity.
Photo-reactivity experiments showed that light exposure on floc resulted in photo-dissolution of POC with the generation of significant amounts of both dissolved OM (DOM) and nutrients (N & P), potentially influencing nutrient dynamics in this ecosystem. The bio-reactivity experiments determined as the amount and rate of CO2 evolution during incubation were found to vary on seasonal and spatial scales and were highly influenced by phosphorus limitation.
Not much is known on OM dynamics in small headwater streams. The objective of this study was to determine carbon dynamics in sediments from intermittent prairie streams, characterized by different vegetation cover for their watershed (C4 grasses) vs. riparian zone (C3 plants). In this study sedimentary OM was characterized using a biomarker and compound specific carbon stable isotope approach. It was found that the biomarker composition of these sediments is dominated by higher plant inputs from the riparian zone, although inputs from adjacent prairie grasses were also apparent. Conflicting to some extent with the River Continuum Concept, sediments of the upper reaches contained more degraded OM, while the lower reaches were enriched in fresh material deriving from higher plants and plankton sources as a result of hydrological regimes and particle sorting.
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Theoretical investigation of protein functions related to electron and ion transports working in thermal fluctuation / イオンと電子が関わる生体分子機能におけるタンパク質熱ゆらぎの役割の理論的解明Cheng, Cheng 25 March 2019 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第21593号 / 理博第4500号 / 新制||理||1646(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)教授 林 重彦, 教授 谷村 吉隆, 教授 寺嶋 正秀 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM
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Rooming Houses and Health: A Case StudyBinch, Joanna 30 November 2021 (has links)
Background: Rooming house residents have high rates of morbidity and mortality, yet little is known about why this disparity in health exists.
Research Question: How are rooming houses linked to health?
Case: Social exclusion of rooming house residents in downtown Ottawa, bounded by the neighborhood, and Ottawa’s political policies at the time of data collection (September 2019-June 2020).
Methodology: A single embedded descriptive case study was informed by multiple sources of evidence, and involved a community advisory group (CAG). Rooming house residents took photos, participated in a community walk-about with participant observations and attended a focus group. Two additional focus groups were conducted; one with fellow rooming house residents, another with the CAG. Interviews with rooming house front-line service providers and a secondary data set of homeless service measures also informed the case.
Findings: 1. Rooming house residents (n=10) took 112 photos, and (n=8) took part in a focus group where two broad themes emerged: Housing is health care, and just managing today. 2. Interviews with front-line service providers (n=11) focused on two themes: There are many costs to living in a rooming house, and rooming house front-line service providers wear many hats. 3. Between a sample of sheltered homeless (n = 60) and rooming house residents (n=52), there was no difference found for several health indicators, including frequency of care received in the emergency room, hospitalization as an inpatient, and if substance use made it difficult to stay or afford housing. Focus groups with rooming house residents who did not take photos (n=10) and the GAG (n=6) contributed to persona co-creation revealing financial and contextual factors affecting the health of rooming house residents.
Conclusion: The shared spaces of rooming houses create a tension between offering community and creating a risk environment. The negative health consequences to living in a rooming house are mitigated by the many roles that rooming house front-line service providers play in filling gaps. This study suggests the need to definitively position rooming house residents on the housing continuum in order to ensure equitable distribution of resources to optimize the health of this vulnerable population.
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IT WOULD BE NICE IF SOMETHING MADE SENSE / IT WOULD BE NICE IF SOMETHING MADE SENSEČížková, Michaela Unknown Date (has links)
I interconnect artist's body with objects of daily use in my work. I'm looking for a new contact and connection where is possibility of contact with disinterested spectator. The result is a series of photo performances
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Photoelectrochemical kinetics of visible-light driven water splitting at Rh∶SrTiO3 based electrodes / Cinétique photo-électrochimique de la photo-dissociation de l’eau assistée par lumière visible sur électrodes à base de Rh∶SrTiO3Antuch Cubillas, Manuel 23 April 2018 (has links)
L’étude de la cinétique de la photodissociation de l’eau assistée par lumière visible a été l’objectif principal de ce travail. En tant que matériau photo-excitable, le semi-conducteur SrTiO₃ dopé au Rh a été utilisé. Le dopage permet l’absorption de lumière visible et donc la transformation d’énergie solaire en combustibles chimiques. Le 1er Chapitre de cette thèse est consacré à une étude bibliographique couvrant les méthodes de caractérisation et les modèles de la cinétique photo-électrochimique. Le 2ème Chapitre traite la description des matériaux et méthodes expérimentaux. Le 3ème Chapitre concerne la caractérisation de la cinétique de la photodissociation de l’eau sur photo-électrodes à base de Rh:SrTiO₃, modifiées en surface par ajout d’un clathrochélate modèle, ou avec du Cu ou du Pt métalliques. Le 4ème Chapitre décrit une étude théorique du mécanisme de la réaction de dégagement d’hydrogène, catalysée par un clathrochélate modèle. Le spectre EXAFS du complexe a été analysé et modélisé, et les intermédiaires importants du mécanisme ont été mis en évidence. Le 5ème Chapitre est consacré à l’étude dynamique de photo-électrodes à base de Rh:SrTiO₃ en utilisant la technique de la photo-tension à lumière modulée. Ce Chapitre présente des résultats inattendus, qui sont rapportés pour la première fois. Ce comportement bizarre a été modélisé par un système d’équations différentielles usuellement utilisées pour décrire ce type de système photo-électrochimique. / The kinetics of water photo-dissociation assisted by visible light was the main topic of this work. The Rh doped SrTiO₃ semiconductor was employed as photo-excitable material. It can absorb visible light and therefore transform solar energy into useful chemical fuels. In this manuscript, a wide bibliographic overview is provided in the 1st Chapter, covering a description of the characterization methods and current models for photoelectrochemical kinetics. The 2nd Chapter is devoted to the description of the materials and methods. The 3rd Chapter deals with the full photoelectrochemical kinetic characterization of water splitting with Rh:SrTiO₃ photoelectrodes, surface-modified by addition of a model clathrochelate or with metallic Cu or Pt. In the 4th Chapter, a theoretical study of the mechanism of hydrogen evolution catalyzed by a model clathrochelate is provided. During the discussion, the EXAFS spectrum of the organometallic complex was thoroughly analyzed and modelled, and the relevant protonated intermediates involved in the mechanism were identified. The 5th Chapter deals with the photoelectrochemical dynamics of illuminated Rh:SrTiO₃ -based photo-electrodes, characterized by the light-modulated photovoltage technique. Unusual results were obtained and are reported in this thesis for the first time. This unexpected dynamic behavior has been modelled by a set of classical differential equations usually used to describe such photo-processes.
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Stimuli-Responsive Materials for Controlled Release ApplicationsLi, Song 04 1900 (has links)
The controlled release of therapeutics has been one of the major challenges for scientists and engineers during the past three decades. To address this outstanding problem, the design and fabrication of stimuli-responsive materials are pursued to guarantee the controlled release of cargo at a specific time and with an accurate amount. Upon applying different stimuli such as light, magnetic field, heat, pH change, enzymes or redox, functional materials change their physicochemical properties through physical transformation or chemical reactions, allowing the release of payload agents on demand.
This dissertation studied three stimuli-responsive membrane systems for controlled release from films of macro sizes to microcapsules of nano sizes. The first membrane system is a polymeric composite film which can decrease and sustain diffusion upon light irradiation. The photo-response of membranes is based on the photoreaction of cinnamic derivatives. The second one is composite membrane which can improve diffusion upon heating. The thermo-response of membranes comes from the volume phase transition ability of hydrogels. The third one is microcapsule which can release encapsulated agents upon light irradiation. The photo-response of capsules results from the photoreaction of nitrobenzyl derivatives.
The study on these membrane systems reveals that stimuli-responsive release can be achieved by utilizing different functional materials on either macro or micro level. Based on the abundant family of smart materials, designing and fabricating stimuli-responsive systems shall lead to various advanced release processes on demand for biomedical applications.
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Optomyography: Detection of muscle surface displacement using reflective photo resistorRaghavendra, Jammalamadaka January 2014 (has links)
A human body can carry out many physiological complex processes which can be mechanical, electrical or bio-chemical. Each mechanical activity generates a signal that describes the characteristics of the particular action in the form of pressure or temperature. Any irregularity in the process changes the usual functioning thus affecting the performance of the system. Several techniques were introduced to evaluate these muscular signals in order to get a deeper understanding of the medical abnormalities. Displacement sensors, laser optics, electrodes, accelerometers and microphones are some of the widely used devices in measuring the electrical and mechanical activities produced in the muscles. The aim of this thesis project was to find and implement a simple non-contact optical method to measure and monitor the displacements caused on the surface of the skin due to muscular movements. In this study, a device was developed using photo electric sensors that can record surface changes caused on the skin due to the movements forearm muscles. / Människokroppens aktiviteter genererar olika mätbara signaler som kan vara biokemiska, elektriska, mekaniska. Naturligtvis är det viktigt att kunna mäta dessa signaler för att kunna veta om kroppens olika organ fungerar som de ska göra eller inte. När det gäller rent mekaniska aktiviteter genereras signaler av olika typer som beskriver denna aktivitet, såsom tryck, temperatur och förflyttning. Om en sådan process avviker från det normala fallet, kommer kroppssystemets prestanda att försämras. Ett antal tekniker utvecklades för att kunna mäta dessa signaler och uppnå djupare förståelse av möjliga icke-normala medicinska konsekvenser. Förflyttningssensorer, laser optik, elektroder, accelerometrar och mikrofoner är exempel på mättekniker som används för att studera elektrisk och mekanisk aktivitet i muskelvävnader. Målet med detta arbete är att hitta, utveckla och implementera en enkel, användarvänlig, beröringsfri, optisk teknik för att mäta och studera de ytliga förflyttningar som förändrar hudytans landskap och resulterar från muskelaktiviteter och rörelser. Detta projekt resulterade i en enkel prototyp för ett mätinstrument som ser ut som ett armband med två fotoelektriska sensorer som används för att mäta hudytans förändringar på grund av olika arm- och handrörelser.
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Bis(Diaryliodonium) Perfluorosulfonimide Zwitterions as Potential Photo Acid GeneratorsMei, Hua, Desmarteau, Darryl D. 01 April 2014 (has links)
Three examples of bis(diaryliodonium) perfluorosulfonimide (BDI-PFSI) zwitterions have been prepared as a potential new class of ionic photo-acid generators for chemically amplified photoresist formulations.
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