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Propriedades ópticas experimentais e teóricas de filmes ultrafinos de polifuoreno / Óptical experimental and theoretical properties of ultra thin polyfluorene filmsLeandro Augusto Zago 13 April 2017 (has links)
A espectroscopia de molécula única (SMS) é uma poderosa técnica para entender como a conformação da cadeia polimérica é modificada por superfícies e interfaces. No presente trabalho, a interação substrato-polímero foi modificada pela alteração da carga superficial do substrato pela modificação do caráter hidrofóbico-hidrófilico da superfície do substrato. A conformação planar / não planar assumida pelo poli (9,9 dioctilfluoreno) (PFO) foi utilizada para acessar os efeitos de substratos e inter-cadeias sobre a conformação do polímero. Usamos a combinação de diferentes tratamentos para alterar superfícies de quartzo inerte de super hidrofílico (ângulo de contato ∼ 0°) para hidrofóbico (ângulo de contato ∼ 80°) quase continuamente. As películas ultrafinas de polímero (<10 nm) e moléculas isoladas podem ser depositadas em diferentes superfícies do substrato por técnica de revestimento por centrifugação de forma controlada, que permitiu a investigação de processos foto físicos a um nível molecular único. Utilizou-se três técnicas espectroscópicas para caracterizar tais filmes ultrafinos, a saber: microscopia de fluorescência confocal equipada com imagens de fluorescência espectral, espectroscopia de absorção UV / Vis e espectroscopia de fotoluminescência dependente da temperatura. As propriedades de emissão e eficiência de filmes de PFO ultrafinos são fortemente afetadas pela presença da interface do substrato. No caso de uma única cadeia de PFO, a fase planar (energia mais baixa) é induzida pela forte interação superfície-polímero no caso da superfície hidrofílica carregada. Além disso, esta interação pode ser fortemente perturbada ou inteiramente destruída por interações entre cadeias. / Single molecule spectroscopy (SMS) is a powerful technique to understand how polymeric chain conformation is modified by surfaces and interfaces [1]. In the present work, substrate-polymer interaction was modified by changing substrate superficial charge by the modification of the hydrophobic-to-hydrophilic character of the substrate surface or by the deposition of charged self-assembling monolayers or polyelectrolytes as well. The planar/non-planar conformation assumed by poly (9,9 dioctylfluorene) (PFO) was used to access the effects of substrates and interchain interactions on the polymer conformation [2]. We used the combination of dif-ferent treatments to change inert quartz surfaces from superhydrophylic (contact angle ∼ 0°) to hydrophobic (contact angle ∼ 80°) almost continuously. Polymer ultrathin films (<10 nm) and isolated chains can be deposited on different substrate surface by spin-coating technique in a controlled way that allowed the investigation of photophysical processes at a single molecular level. We employed three spectroscopic techniques to characterize such ultrathin films, namely: confocal fluorescence microscopy equipped with spectral facilities, UV/Vis absorption spectroscopy and temperature dependent photoluminescence spectroscopy. The emission properties and efficiency of ultrathin PFO films are strongly affected by presence of the inert substrate interface. In the case of single PFO chain, the planar phase (lower energy) is induced by the strong surface-polymer interaction in the case of charged hydrophilic surface. Moreover, this interaction can be strongly perturbed or entirely disrupted by interchain interactions.
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Estudo nanogravimétrico da influência do ânion BF4- em eletrocatálise / Nanogravimetric study of the influence of the BF4- anion in electrocatalysisAdriano Lopes Santos 18 June 2010 (has links)
Em tempos nos quais a sociedade se volta a reflexões sobre questões climáticas e energéticas, células a combustível surgem como uma alternativa promissora no âmbito das políticas que visam o desenvolvimento sustentável. Nesse sentido, há ainda desafios a serem superados nas esferas fundamental e aplicada. Entender o papel das espécies presentes no eletrólito de suporte é fundamental em tal descrição. Especificamente no caso de ânions dissolvidos no eletrólito, o papel mais comumente atribuído é o de inibir o processo eletrocatalítico de interesse, por meio do bloqueio de sítios superficiais. No entanto, atribui-se recentemente ao ânion BF4- um efeito diverso; o aumento dos valores de corrente de eletro-oxidação em baixos potenciais. Apresenta-se na presente dissertação, um estudo sistemático deste processo, empregando a técnica da nanobalança eletroquímica a cristal de quartzo (NECQ), em conjunto com técnicas eletroquímicas tradicionais. Tal estudo revelou a ocorrência de diferenças notáveis nos perfis voltamassométricos do sistema eletroquímico quando da adição de pequenas quantidades do reagente HBF4. Tais diferenças têm caráter bastante especial, uma vez que nos perfis voltamétricos não são observadas diferenças marcantes nos valores de corrente entre o sistema eletroquímico com a adição de pequenas quantidades do reagente HBF4 e o sistema eletroquímico sem a adição desse reagente. À partir dos métodos utilizados e das evidências experimentais observadas, é possível inferir que o comportamento peculiar até então atribuído ao HBF4 na verdade resulta de uma contaminação com o semimetal arsênio, apesar de o rótulo do fabricante não informar sobre a possibilidade da ocorrência de traços do semimetal. / In times where the society turns its reflections on climate and energy questions, fuel cells appear as a promising alternative for the policies aimed at sustainable development. In this sense, there are still challenges to overcome in fundamental and applied levels. Understand the role of species in the supporting electrolyte is crucial in such a description. Specifically in the case of anions dissolved in the electrolyte, the most commonly assigned role is to inhibit the electrocatalytic process of interest, through blockade of surface sites. However, to the anion BF4- is recently attributed a diverse effect, the increase of the current values of electro-oxidation at low potentials. It is presented in this dissertation, a systematic study of this process, using the technique of the electrochemical quartz crystal nanobalança (EQCN), combined with traditional electrochemical techniques. This study revealed the occurrence of remarkable differences in the voltamassometric profiles of the electrochemical system when adding small amounts of reagent HBF4. Such differences are special features, since in the voltammetric profiles marked differences are not observed in current values between the electrochemical system with or without the addition of small amounts of reagent HBF4. On the basis of methods utilized and the experimental evidence observed, it is possible to infer that the peculiar behavior previously attributed to HBF4 actually results from a semimetal contamination with arsenic, although the manufacturer\'s label gives no information about the occurrence of traces of the semimetal.
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Eletrofiação de nanofibras poliméricas de poliacrilonitrila e polifluoreto de vinilideno, incorporadas com negro de fumo e ftalocianina de cobre, visando aplicações em dispositivos sensores. / Electrospinning of polyacrylonitrile and polyvynilidene fluoride nanofibers incorporate with carbon black end copper phthalocyanine to applications in sensors devices.Demetrius Saraiva Gomes 23 February 2018 (has links)
O presente trabalho tem como objetivo principal a eletrofiação de nanofibras poliméricas de poliacrilonitrila (PAN) e polifluoreto de vinilideno (PVDF), incorporadas com negro de fumo (NF) e ftalocianina de cobre (CuPc), visando aplicações em dispositivos sensores. Inicialmente foram preparadas soluções de PAN puro a 6 % em peso e PVDF puro a 20% em peso e foram misturadas a essas soluções partículas de negro de fumo e ftalocianina de cobre, obtendo soluções de PAN/NF, PVDF/NF, PAN/CuPc e PVDF/CuPc. Foi determinada a viscosidade absoluta das soluções. Realizou-se a eletrofiação para obtenção de nanofibras que foram caracterizadas segundo o diâmetro e morfologia, usando microscópio óptico e microscópio eletrônico de varredura. Para avaliar as interações polímero-polímero, polímero-partícula foram analisadas por espectroscopia FITR e Raman. Com as fibras de PAN/NF foi analisada a resistência e condutância elétrica das membranas usando um picoamperímetro digital, visando aplicação como filtro eletrostático. Foi construído canal na lâmina de silício usando um feixe de laser visando a deposição de fibras dentro do canal usando a técnica de focagem eletrodinâmica com tensão aplicada em máscaras de cobre. Foi usada a técnica da microbalança de cristal de quartzo para determinar a variação de massa adsorvida por membranas de PAN/CuPc e PVDF/CuPc por meio da medida da variação de frequência usando um frequencímetro digital, onde se observou que essas membranas são promissoras para atuar como sensores de vapor de amônia. / The main objective of this work is the incorporation of different particles in order to electrospun polymeric nanofibers of polyacrylonitrile (PAN) and polyvinylidene fluoride (PVDF), aiming at applications in sensor devices. Initially, solutions of PAN pure 6 wt% and PVDF pure 20 wt% were prepared and these solutions were mixed with carbon black (NF) particles and copper phthalocyanine (CuPc), obtaining solutions of PAN/NF, PVDF/NF, PAN/CuPc and PVDF/CuPc. The absolute viscosity of the solutions was determined. The electrospinning was performed to obtain nanofibers that were characterized according to the diameter and morphology, using optical microscope and scanning electron microscopy. To evaluate the polymer-polymer and polymer-particle interactions, FITR and Raman spectroscopy were performed. The resistance and conductance of the membranes electrospun from PAN/NF solution were analyzed using a digital picoammeter, and an increase in the resistance was measured. This result shows that the membrane is suitable to be applied as electrostatic filter. A channel was constructed on the silicon wafer using a laser beam for the deposition of fibers inside the channel using the electrodynamic focusing technique. The quartz crystal microbalance technique was used to determine the applicability of the membranes as sensor layer. The results of PAN/CuPc and PVDF/CuPc membranes suggests that these membranes are promising to act such as ammonia vapor sensors.
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Desenvolvimento de equipamento de teste de estruturas miniaturizadas: testes em estrutura útil na eliminação de partículas. / Development of machine to test miniaturized structures: tests in util structure from particles elimination.Leandro Colevati dos Santos 26 May 2006 (has links)
Amostras com pequenos volumes e matrizes complexas, como sistemas biológicos, necessitam de preparação criteriosa. Muitas dessas amostras são melhor analizadas em estruturas miniaturizadas devido à necessidade de detectar células e microorganismos em diferentes matrizes. Por essa razão, equipamentos capazes de detectar e destruir microorganismos e estruturas para prévia retenção desses se faz necessários na vida moderna. Chicanas, constrições usadas para reduzir velocidade de fluxo, que podem ser utilizadas para reter compostos, são estruturas macroscópicas para remover resíduos de lagos, fazendas e etc. e chicanas miniaturizadas foram usadas para a adsorção de compostos orgânicos do ar e da água. Assim, esse trabalho tem dois diferentes objetivos: 1) Produção de um equipamento de baixo custo, para teste de partículas ou eliminação de microorganismos e 2) O desenvolvimento de estruturas miniaturizadas para retenção e/ou seleção de partículas e substâncias viscosas de um fluido líquido. A metodologia utilizada foi: 1) Dois software foram escolhidos para esse trabalho. O LabVIEW® 7.0 foi utilizado como plataforma para o desenvolvimento do software do equipamento e o FemLAB® 3.1 para a simulação de estruturas. O equipamento produzido usou Microbalança de Quartzo como detector e um sistema de admissão baseado em uma bomba e tubos. 2) O desenho da estrutura foi otimizado por simulação do comportamento do fluxo. A estrutura otimizada foi feita desmontável, e usinada em polimetilmetacrilato ? acrílico, com ferramentas convencionais. Acrílico foi usado devido à sua transparência óptica, que permite testes com microsocpia óptica. As simulações consideraram N2 e Água como fluidos gasoso e líquido, respectivamente. Avaliou-se o comportamento das partículas (50?m and 13?m) em fluxo gasoso e polidimetilsiloxano (silicone, com viscosidade de 350 cSt) e partículas em fluxo líquido. As estruturas foram caracterizadas quanto à adsorção e retenção de partículas usando equipamento desenvolvido e por microscopia óptica. As estruturas foram, também, continuamente fotografadas durante a execução do experimento e fotos foram utilizadas para determinar o comportamento do fluxo. Os reagentes foram injetados na estrutura em pequenos pulsos. O equipamento mostrou boa performance para detecção de adsorção em fluxo líquido e reprodutibilidade no monitoramento do aquecimento de estruturas. As chicanas mostraram boa capacidade de reter partículas grandes (50?m), mas não pequenas (13?m), tanto para fluxos gasosos como líquidos. Contudo, a estrutura tem pequena capacidade de carga para fluidos líquidos (? 1mg); além disso, a retenção de amostras de silicone na estrutura, utilizando fluido líquido, ocorreu devido à diferença de velocidade entre os fluidos. A simulação e os resultados experimentais apresentam boa correlação. Assim, a chicana mostrou a possibilidade de, seletivamente, separar partículas em fluxos gasosos e líquidos ou reter substâncias viscosas em fluxo líquido. Esses resultados apontam para diversas aplicações, como por exemplo, pré-tratamento para análises biológicas e retenção ou eliminação de microorganismos. / Samples with small volume and complex matrix, such as biological systems, require careful preparation. Many of these samples are better analyzed in miniaturized structures owing to the need of detect cells and microorganisms in different arrays. Therefore equipment able to detect and destroy microorganisms and structures to previously retain them are require in the modern life. Chicanes, i.e. constrictions used to reduce flow velocity, can be useful to retain compounds, are macroscopic devices to remove waste removal from lakes, farms, etc. and miniaturized chicane was used to adsorption of organic compounds from air and water. Thus, this work has two different targets: 1) Production of a low-cost equipment useful for tests of particle or microorganisms elimination and 2) The development of miniaturized structures useful for retention and/or selection of particles and viscous substances from a liquid flow. The methodology used was: 1) Two software were chosen to this work. The LabVIEW® 7.0 was used for development of equipment software and FemLAB® 3.1 for structures simulation. The equipment production used Quartz Crystal Microbalance as detector and an admission system based on simple pumps and plumbing. 2) The design of the structure design was optimized using flow simulation. The optimized design was manufactured in poly(methyl methacrylate) -acrylic, with conventional tools. Acrylic was used due to the optical transparency that allows photographic tests and the structures can be easily disassembled. The simulations considered nitrogen and water for gaseous and liquid flow, respectively. It was evaluated the behavior of particles (50?m and 13?m) on gaseous flow and polydimethylsiloxane (silicone, viscosity of 350 cSt) and particles on liquid flow. The structures were characterized using equipment produced to measure adsorption and optical microscopy to evaluate particle retention. The structures were also continuously photographed during the experiments and the photos were analyzed to determine flow behavior. The reactants were inserted in the structure in small pulses. The equipment shows good performance for detection of adsorption in liquid flows and reproducibility on monitoring heated structures. Chicanes showed good ability to retain big particles (50 ?m) but not small ones (13 ?m) for both liquid and gaseous flow. However, the structure has small load capacity for liquids (? 1 mg). Moreover, the retention of silicone samples in the structure on liquid flow occurs due to the difference in the fluid velocity. The simulation and experimental results are in good agreement and also chicane structure shows the possibility of selectively separate particles from gaseous and liquid flow or retain viscous substances from a liquid flow. These results point out to several applications, such as sample pretreatment for biological analysis and microorganism retention or elimination.
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Quartz probes for embedded micro-robotics and imaging / Sondes de quartz pour la micro-robotique intégrée et l'imagerieAbrahamians Khanghah, Jean-Ochin 10 May 2016 (has links)
Les sondes basées sur des résonateurs en quartz sont des capteurs disposant d'une autonomie en termes d'excitation et d'acquisition, et à cet égard présentent de nombreux avantages par rapport aux poutres cantilever qui ont jusqu'à présent dominé dans les applications de micro-caractérisation directe. Un de ces avantages est qu'elles peuvent êtres embarquées et calibrées sans recours à un système de déflection laser. Ces outils plus compacts et autosuffisants peuvent en conséquence être aisément intégrés et contrôlés au sein d'un microscope électronique à balayage, qui permet une observation globale rapide souvent privilégiée dans la recherche en micro-robotique. Le développement de ces sondes est de plus avantagé de par le fait qu'elles sont constituées de composants électroniques standards répandus dans le commerce, et qu'elles peuvent être adaptées à des usages spécifiques par l'ajout d'une micro-pointe. Les sondes de quartz dans la littérature sont cependant souvent basées sur des composants à fréquence d'oscillation limitée, et une plus grande vitesse d'opération serait utile à l'ensemble de leurs applications. C'est dans ce contexte que nous nous intéressons à des composants à plus haute fréquence, et au contrôle de sondes dans un microscope électronique propre à leur utilisation ciblée en micro-robotique et en imagerie. Les propriétés de ces sondes sont tout d'abord examinées dans le but de pouvoir évaluer et exploiter des résonateurs à plus haute fréquence; nous montrons ensuite que des sondes basées sur des résonateurs à cisaillement d'épaisseur atteignent de plus hautes vitesses en imagerie, ce qui les rend prometteuses pour des applications rapides ne requérant pas une haute résolution. Enfin, nous intégrons une sonde diapason dans un MEB, et établissons ainsi une preuve de concept pour la cartographie en raideur de micro-membranes fragiles. / As self-sensing and self-exciting tools, quartz probes present many advantages over the heretofore dominant silicon cantilevers for mechanical micro-sensing applications. One of these advantages is that they can be embedded and calibrated without the need for a laser deflection setup. The more compact and self-sufficient tools can therefore be readily integrated and controlled with Scanning Electron Microscopy, which is favoured at the smaller scales of micro-robotic research. More generally, the development and use of quartz probes is bolstered by the fact that they can be fabricated from widely commercialized quartz components and customised through the addition of a microtip. The quartz probes found in the literature are however largely based on components with limited oscillation frequencies, and could benefit from higher operating speeds. In this context, we address the frequency improvement and embedded control of AFM probes with regard to their use in targeted micro-robotics and imaging. The properties of quartz probes are first covered towards the evaluation and use of higher frequency components; we next demonstrate that faster scanning can be achieved with quartz probes made from thickness shear resonators, making them suitable for fast applications which do not require high sensitivity. Lastly, we integrate a tuning fork probe inside a SEM, and establish through it a proof of concept for the non-destructive stiffness mapping of fragile micro-membranes.
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A study on the use of OpenGL in window systems / En studie av hur OpenGL används i fönstersystemPersson, Johan January 2004 (has links)
OpenGL is getting used more in window system as a way of improving performance and enabling new functionality. Examples of two systems using different approaches of how OpenGL is being used are Quartz Extreme and Fresco. Quartz Extreme uses window composition which assures fast redisplay and Fresco on the other hand uses a structured graphics approach which utilises OpenGL on a much lower level compared to Quartz Extreme which operates at a window level. Fresco’s way brings great flexibility and an ability to mix 2D and 3D-objects on the desktop. But each of the approaches has its problems; Quartz extreme requires a large amount of memory for buffering of the window contents and Fresco has performance problems when redisplaying complex structures. / OpenGL används mer och mer i fönstersystem som ett sätt att förbättra prestanda och möjliggöra ny funktionalitet. Två exempel på olika sätt att nyttja OpenGL är Quartz Extreme och Fresco, Quartz Extreme använder fönster komposition vilket garanterar snabbt omritning av fönster medan Fresco använder Structured Graphics vilket använder OpenGL på en mycket lägre nivå inom fönstersystemet jämfört med Quartz Extreme som är på fönster nivå. Frescos angreppsätt medför en större flexibilitet och möjligheten att blanda 2D och 3D-objekt på skrivbordet. Men bägge angreppsätten har sina nackdelar; Quartz Extreme kräver en stor mängd minne eftersom den buffrar fönsterinnehållet och Fresco får problem med prestandan vid omritning av komplexa strukturer.
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Probing the biocompatibility of biomedical interfaces using the Quartz Crystal Microbalance with DissipationCromhout, Mary January 2011 (has links)
The biomedical application of nanotechnology has come into the spotlight, with the promise of ‘personalised’ therapeutics that couple early diagnosis with targeted therapeutic activity. Due to the rapid growth of the biomedical applications of nanoparticles, along with the lack of understanding concerning their interactions with biomolecules, there is a pressing need for the development of standard methods directed at investigating the effect of introducing these unique particles into the human body. The central aim of this research is to establish a platform directed at assessing the biological fate of pioneering therapeutic particulate agents, such as metallophthalocyanines (MPcs) and multi-walled carbon nanotubes (FMWCNTs). In particular, we proposed, that Quartz Crystal Microbalance with Dissipation (QCM-D) technology may be employed to assess the composition of blood protein corona deposited on the therapeutic surface, and subsequently assess the biocompatibility of such particles. The proposed method of protein detection utilises the nanogram sensitivity of QCM-D technology to monitor highly specific antibody-antigen interactions. In particular those interactions which occur when probe antibodies are used to detect adsorbed blood proteins deposited on target particle-modified sensor surfaces. Protein detection analysis was directed toward identification of surface bound human serum albumin, complement factor C3c, and human plasma fibrinogen. Preliminary analysis of generic biomedical surfaces indicated human serum albumin demonstrates a higher binding affinity towards positively charged surfaces (i.e. cysteamine self-assembled monolayer), followed by hydrophobic surfaces. Detection of complement C3c, corresponded with literature, where lower levels were detected on negatively charged surfaces (i.e. mercapto undecanoic acid self-assembled monolayer), and higher levels of more hydrophobic surfaces (i.e. 11-amino undecane thiol self-assembled monolayer). Human plasma fibrinogen was observed to favour hydrophilic over hydrophobic self-assembled monolayer surfaces, which was in accordance with literature. Application of the proposed protein detection method for biocompatibility analysis of target therapeutic molecules, namely metallophthalocyanines and acid functionalised multi-walled carbon nanotubes, demonstrated a dependence on modified-surface film characteristics, such as surface charge and topography with regards to human serum albumin and human plasma fibrinogen analysis representing new insights into their potential biomolecular interactions The highest levels of detected human serum albumin and complement C3c were detected on the GePcSmix-modified surfaces. AlPcSmix-modified surfaces analysis suggested the highest levels of human plasma fibrinogen. Two methods of acid functionalisation were employed, using both nitric and sulphuric acid, and pure nitric acid. A general increase in detected human serum albumin, corresponding with an increase in functionalisation time, was observed. Complement C3c detection suggested an increase in deposited complement C3c, with increasing functionalisation time, when assessing nitric acid functionalised multi-walled carbon nanotubes, and a decrease, with increasing functionalisation time, when assessing nitric and sulphuric acid functionalised multi-walled carbon nanotubes. Analysis of human plasma fibrinogen was inconclusive, as were cytotoxicity experiments utilising MCF-7 cells in the presence of metallophthalocyanine complexes, raising simultaneously important considerations for their application and study. In the first such detailed examination of its kind it was concluded that the proposed method of protein detection, using QCM-D, allows for the rudimentary but rapid means of analysis of select protein corona deposited on particulate biomedical surfaces.
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Glaciations and climate in the Cenozoic Arctic:evidence from microtextures of ice-rafted quartz grainsImmonen, N. (Ninna) 18 November 2014 (has links)
Abstract
Numerous efforts have been made in recent decades to recover the climate history of the Arctic region. The present PhD study is one of them, focusing on terrestrial sediments which were deposited in the Arctic Ocean during the Cenozoic. The Arctic Ocean, surrounded by land on all sides, is among the most important marine archives of sediments that record information of palaeoclimates, including cold climates with extensive glaciation. Evidence of ancient glaciations is generally retraced by observing widespread terrestrial ice-rafted debris (IRD) deposits on the seafloor, as large amounts of IRD are transported by icebergs during deglacial phases. However, it has been shown that sea ice also transports abundant IRD from shallow continental shelves. What is worth noticing is that glaciers and sea ice influence climate variables differently, and therefore, to model climate in past glaciations, IRD released from these factors should be differentiated. The relative proportions of glacial IRD and non-glacial IRD were determined in this study from two central Arctic Ocean expedition site recoveries: the Integrated Ocean Drilling Program’s (IODP) Arctic Coring Expedition (ACEX) 302 composite core recovery and the Swedish Polar Research Expedition’s Arctic Ocean 1996 (AO96) piston core 96/12-1pc. The main objective was to characterise and quantify the process- and environment-related microtextures of quartz sand grain surfaces. The data were subjected to statistical methods and a multiproxy approach, and the results were used to define the dynamics and timing of palaeoglaciations. The results indicate that the signals of glacial and non-glacial continental processes and the involvement of iceberg versus sea-ice rafting can be distinguished by microtextural and statistical analyses. Improvements in the general interpretation of late Pleistocene Eurasian ice sheet distribution and dynamics are provided: late MIS 4 (ca. 62–67 ka) reflects a deglacial phase with increased fluvial activity, whereas MIS 3 at ca. 45 ka is related to glacial advance characterised by the oscillating and calving Barents-Kara ice sheet. Based on the results of this study, the early glacial ice on the Arctic continent can be retraced back to the late Palaeocene ca. 56 Ma. / Tiivistelmä
Arktisen alueen ilmastohistoriaa on pyritty selvittämään usein eri tavoin viime vuosikymmenten aikana. Tässä tutkimuksessa on keskitytty Jäämereen kerrostuneiden mantereelta peräisin olevien sedimenttien ominaisuuksiin. Jäämeri on yksi tärkeimmistä mannerten ympäröimistä merialueista jonka pohjan sedimentteihin on tallentunut tietoa menneistä ilmasto-oloista, kuten laajoista jäätiköitymisistä. Jään kuljettaman sedimenttiaineksen runsas esiintyminen merenpohjan kerrostumissa on yleisesti tulkittu todisteeksi menneistä jäätiköitymisistä, sillä jäävuorikuljetus on runsainta mannerjäätikön sulamisvaiheessa. Myös merijää voi kuljettaa runsaasti sedimenttiainesta joka on peräisin matalalta mannerjalustavyöhykkeeltä. Jäätiköiden ja merijään vaikutus ilmastomuuttujiin on hyvin erilainen ja siksi on tärkeää selvittää niiden osallisuus eri ilmastovaiheissa. Tässä tutkimuksessa määritettiin jäävuorien ja merijään kuljettaman sedimenttiaineksen suhteelliset osuudet kahdesta keskeisen Jäämeren tutkimusmatkan kaira-aineistosta: Integrated Ocean Drilling Program (IODP) -ohjelman Arctic Coring Expedition 302 (ACEX) -tutkimusmatkan yhdistetystä kaira-aineistosta ja Swedish Polar Research Expedition Arctic Ocean 1996 (AO96) -tutkimusmatkan kaira-aineistosta 96/12-1pc. Tärkein tavoite oli kuvata ja laskennallisesti määrittää kvartsihiekkarakeiden pintamikrotekstuurit, jotka ovat syntyneet erilaisissa prosesseissa ja ympäristöissä. Aineistoa tarkasteltiin tilastollisin- ja moniaineistomenetelmin, ja tuloksia käytettiin jäätiköiden dynamiikan ja ajoituksen määrittämiseen. Tämän tutkimuksen johtopäätöksenä voidaan todeta että jäätikköön ja ei-jäätikköön liittyvät mantereiset prosessesit, sekä jäävuori- ja merijääkuljetuksen osallisuus, voidaan erottaa mikrotekstuuri- ja tilastollisen analyysin avulla. Tutkimus tarkentaa tulkintoja myöhäis-Pleistoseenin jäätiköiden alueellisesta levinneisyydestä ja dynamiikasta: myöhäinen MIS 4 (noin 62–67 ka) oli deglasiaalivaihetta jolloin fluviaalitoiminta oli aktiivista, kun taas MIS 3 noin 45 ka liittyy jäätiköitymisvaiheeseen jolloin Barentsin-Karan jääkenttä oskilloi ja jäävuorikuljetus oli runsasta. Tutkimuksen tuloksena voidaan myös tarkentaa varhaisten Arktisten jäätiköitymisten ajankohta myöhäiseen Paleoseeniin noin 56 Ma.
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Anisotropie, fusion partielle et déformation de la croûte continentale : étude expérimentale et observations de terrain / Anisotropy, partial melting and deformation of the continental crust : experimental study and field observationsFauconnier, Julien 22 September 2016 (has links)
La localisation de la déformation est une caractéristique nécessaire de la tectonique. Pour localiser la déformation, une roche doit subir un affaiblissement. Le processus affaiblissant principal des roches est l'interconnexion de phases faibles. Dans le cas de la croûte continentale, les phases faibles étant le plus souvent responsables de la localisation sont les micas et les liquides silicatés résultant de la fusion partielle. Bien qu'il existe des études expérimentales sur la rhéologie des micas, il y a très peu d'études sur l'impact des micas sur la localisation dans les conditions de la croûte continentale inférieure. De même, les précédentes études expérimentales montrent l'effet de la fusion partielle sur la résistance des roches mais elles utilisent toutes un matériel de départ isotrope. Or la croûte subissant la fusion partielle dans les orogènes est susceptible d'être préalablement déformée et donc anisotrope. Dans le but d'apporter de nouvelles données sur le comportement mécanique et les microstructures de la croûte continentale anisotrope, ainsi que sur l'effet des micas sur la localisation de la déformation, cette thèse propose de réaliser une série d’expériences en presse de Griggs. Cette approche expérimentale est aussi couplée à un travail de terrain sur la zone de faille de Møre og Trøndelag (Norvège). Cette structure étant un zone de cisaillement d'échelle crustale dont la cinématique est partiellement synchrone de la fusion partielle, elle est adaptée à l'étude naturelle des relations entre fusion partielle et déformation. / Strain localization is a necessary feature of tectonic. To be able to localize deformation, rocks must undergo weakening. The main weakening process is weak phase interconnection. For continental crust, weak phases that are the most often responsible of strain localization are micas and melt. Although previous experimental studies exist about rheological properties of micas, none are about the effect of micas on the strain localization in the lower continental crust conditions. Previous experimental studies about the effect of partial melting were always done with isotropic starting material. But continental crust which undergo partial melting is very likely to be deformed before melting and therefore to be highly anisotropic. In the aim to bring new data about mechanical behavior and microstructures of anisotropic continental crust, as well as the effect of micas on strain localization, this thesis propose to conduct a series of experiments in a Griggs apparatus. This experimental approach is also coupled with field work on the Møre og Trøndelag Fault Zone (Norway). This crustal scale shear zone was partially synchronous with partial melting and therefore is well suited for studying relation ship between deformation and partial melting
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Optical detection of (bio)molecules / Détection optique des (bio)moléculesJia, Kun 10 December 2013 (has links)
Les biocapteurs optiques ont connu une évolution sans précédent au cours des dernières années, principalement en raison de la forte interaction entre la biotechnologie, l’optique et la chimie des matériaux. Dans cette thèse, deux différentes plates-formes de biocapteurs optiques ont été conçues pour la détection sensible et spécifique des biomolécules. Plus précisément, le premier système de détection optique est construit sur la base de la bioluminescence de cellules bactériennes d'Escherichia coli génétiquement modifiées. L’émission de lumière induite par cette interaction peut donc être utilisée pour la détection des substances toxiques. Le second système utilise des nanoparticules de métaux précieux (or et argent) aux propriétés plasmoniques accordables qui permettent de sonder les interactions des biomolécules spécifiques à l'interface nano-bio par la résonance plasmonique de surface (LSPR). Ces nanoparticules ont été obtenues par traitement thermique à haute température d’un film métallique déposé sur du verre à l’aide d’une grille de TEM ou déposé sur une couche de bactéries fixée sur le verre. Après une optimisation appropriée des nanostructures métalliques en termes de morphologie et de fonctionnalisation, une sensibilité élevée et une grande spécificité peuvent être simultanément obtenues avec ces immunocapteurs plasmonique. Ces deux plateformes ont été utilisées pour détecter des pesticides comme le carbofuran et l’atrazine / Optical biosensors have witnessed unprecedented developments over recent years, mainly due to the lively interplay between biotechnology, optical physics and materials chemistry. In this thesis, two different optical biosensing platforms have been designed for sensitive and specific detection of (bio)molecules. Specifically, the first optical detection system is constructed on the basis of bioluminescence derived from engineered Escherichia coli bacterial cells. Upon stressed by the toxic compounds, the bacterial cells produce light via a range of complex biochemical reactions in vivo and the resulted bioluminescent evolution thus can be used for toxicant detection. The bacterial bioluminescent assays are able to provide competitive sensitivity, while they are limited in the specificity. Therefore, the second optical detection platform is built on the localized surface plasmon resonance (LSPR) immunosensors. In this optical biosensor, the noble metal (gold and silver) nanoparticles with tunable plasmonic properties are used as transducer for probing the specific biomolecules interactions occurred in the nano-bio interface. These nanoparticles were obtained after a high temperature thermal treatment of an initially thin-metallic film deposited on a glass substrate through a TEM grid or on a bacteria layer fixed on the glass. After appropriate optimization on metal nanostructures morphology and surface biomodification, the applicable sensitivity and specificity can be both guaranteed in this LSPR immunosensor
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