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Photon-pair generation in hollow-core photonic-crystal fiber / Génération de paires de photons dans les fibres à cristaux photoniques à coeur creuxCordier, Martin 17 May 2019 (has links)
Les sources de paires de photons sont un composant essentiel des technologies émergentes en information quantique. De nombreux travaux ont permis des avancées importantes utilisant des processus non linéaires d'ordre 2 dans les cristaux et les guides d'ondes, et d'ordre 3 dans les fibres. Les limitations viennent dans le premier cas, des pertes et en particulier des pertes de couplage avec les fibres optiques et dans le second cas, du bruit dû à l'effet Raman dont le spectre est très large dans les fibres de silice. Ce projet propose une nouvelle architecture basée sur des fibres à cristal photonique à coeur creux (FCPCC) que l'on peut remplir de liquide ou de gaz non linéaire. Cette configuration permet la génération paramétrique de paires de photons corrélés par mélange à quatre ondes sans l'inconvénient de la diffusion Raman. Cette technologie offre une large gamme de paramètres à explorer en s'appuyant sur les propriétés physiques et linéaires contrôlables des FCPCC et la possibilité de remplissage de ces fibres avec des fluides aux propriétés non-linéaires variées. En effet, par une conception judicieuse de la FCPCC et un choix approprié du liquide ou du gaz, il est possible de (i) contrôler la dispersion et la transmission pour générer des photons corrélés sur une large gamme spectrale avec la condition d'accord de phase la plus favorable, (ii) d'ajuster la taille de coeur de la fibre et/ou sa forme pour augmenter sa non-linéarité ou son efficacité de couplage avec d'autres fibres et (iii) de s'affranchir totalement de l'effet Raman si on utilise par exemple un gaz monoatomique, ou d'obtenir des raies Raman fines, aisément discriminables des raies paramétriques dans le cas d'un liquide. / Photon pair sources are an essential component of the emerging quantum information technology. Despite ingenious proposals being explored in the recent years based on either second order nonlinear processes in crystals and waveguides or on third order processes in fibers, limitations remain, due to losses and specifically coupling losses in the former case and due to Raman generation in silica, giving rise to a broad spectrum noise in the latter. These limitations have been challenging to lift because of the limited alternative nonlinear materials that fulfil the conditions for the generation of bright and high fidelity photon pairs in integrable photonic structures. In the present project, we develop a new and versatile type of photonic architecture for quantum information applications that offers access to a variety of nonlinear optical materials that are micro-structured in optical fiber forms to generate photon pairs, without the drawback of Raman scattering and with a large design parameter-space. Indeed, with a careful design of the HCPCF along with the appropriate choice of fluid, one can (i) control the dispersion and the transmission to generate photons with the most favourable phase-matching condition over a large spectral range, (ii) adjust the fibre core size and/or shape to enhance nonlinearity or the coupling efficiency with other fibres, (iii) totally suppress the Raman effect in monoatomic gases for instance or have only narrow and separated Raman lines that can thus be easily separated from the useful parametric lines in liquids.
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The differentiation between variability uncertainty and knowledge uncertainty in life cycle assessment: A product carbon footprint of bath powder “Blaue Traube”Budzinski, Maik January 2012 (has links)
The following thesis deals with methods to increase the reliability of the results in life cycle assessment. The paper is divided into two parts. The first part points out the typologies and sources of uncertainty in LCA and summarises the existing methods dealing with it. The methods are critically discussed and pros and cons are contrasted. Within the second part a case study is carried out. This study calculates the carbon footprint of a cosmetic product of Li-iL GmbH. Thereby the whole life cycle of the powder bath Blaue Traube is analysed. To increase the reliability of the result a procedure, derived from the first part, is applied. Recommendations to enhance the product´s sustainability are then given to the decision-makers of the company. Finally the applied procedure for dealing with uncertainty in LCAs is evaluated.
The aims of the thesis are to make a contribution to the understanding of uncertainty in life cycle assessment and to deal with it in a more consistent manner. As well, the carbon footprint of the powder bath shall be based on appropriate assumptions and shall consider occurring uncertainties.
Basing on discussed problems, a method is introduced to avoid the problematic merging of variability uncertainty and data uncertainty to generate probability distributions. The introduced uncertainty importance analysis allows a consistent differentiation of these types of uncertainty. Furthermore an assessment of the used data of LCA studies is possible.
The method is applied at a PCF study of the bath powder Blaue Traube of Li-iL GmbH. Thereby the analysis is carried out over the whole life cycle (cradle-to-grave) as well as cradle-to-gate. The study gives a practical example to the company determining the carbon footprint of products. In addition, it meets the requirements of ISO guidelines of publishing the study and comparing it with other products.
Within the PCF study the introduced method allows a differentiation of variability uncertainty and knowledge uncertainty. The included uncertainty importance analysis supports the assessment of each aggregated unit process within the analysed product system. Finally this analysis can provide a basis to collect additional, more reliable or uncertain data for critical processes.
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Le PCF et les usages du passé résistant (1944-1974) / The FCP and the political usages of the past (1944-1974)Campo, Silvina 03 December 2014 (has links)
Les usages politiques du passé de la Résistance sont au cœur de cette thèse. Cette recherche n’entend donc pas se centrer sur la Résistance au sens strict, mais sur les formes d’instrumentalisation de ce passé, au sein d’un groupe : le Parti Communiste Français. Parmi les passés choisis par le PCF, la Résistance occupe une place déterminante, en raison du réel engagement communiste dans l’armée des ombres, ainsi qu’en raison du brevet de patriotisme qu’elle offrait à une formation créditée d’une fidélité aveugle à Moscou. La participation des communistes à l’épopée résistante leur a permis de reconquérir de la crédibilité et de consolider leur position dans un espace public où ils risquaient d’être disqualifiés en raison des positions adoptées par le parti en 1939-1941. La pluralité des significations attachées à ce passé et la fluidité des interprétations attribuées ont permis l’adaptation à la réalité dans laquelle agissaient les communistes. Ainsi, il a été possible de répondre aux objectifs divers que s’assignait le PCF. La période étudiée s’ouvre en 1944, avec la libération d’une grande partie du territoire français, même si la guerre n’est alors pas finie. L’étude s’achève avec l’année 1974, date significative que signale le XXXème anniversaire de la Libération dans le contexte national de la fin des Trente Glorieuses. / The political exploitation of its involvement in the resistance movement is the subject of this thesis. The objective of this study is not the Resistance per se but how it was used for political purposes by the French Communist Party. The Resistance is an essential period for the FCP not only because of its real involvement in the Resistance movement but also because this involvement was used to hide its blind alliance to Moscow. The involvement of the FCP in the Resistance allowed it to regain credibility and to strengthen its position in despite the errors committed between 1939 and 1941. The multiple interpretations and exploitations of its involvement in the Resistance were adapted by the party according to its political objectives and needs in any given moment. The historical period of this research begin in 1944 with the Liberation and ends in 1974, the 30th Anniversary of this date.
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Shadow Mapping com múltiplos valores de profundidade / Multiple depth shadow mapsPagot, Christian Azambuja January 2005 (has links)
Um dos algoritmos para cálculo de sombras mais eficientes existentes atualmente é o Shadow Mapping de Williams. Ele é simples, robusto e facilmente mapeável para o hardware gráfico existente. Este algoritmo conta com duas etapas. A primeira é responsável pela geração de um depth buffer (Shadow Map) a partir do ponto de vista da luz. Na segunda etapa a imagem final da cena é gerada a partir do ponto de vista da câmera. De maneira a determinar se os pixels da imagem final estão iluminados ou em sombra, cada pixel é transformado para o espaço da luz e testado contra o Shadow Map. Shadow Maps tradicionais armazenam apenas um valor de profundidade por célula, fazendo com que os testes de sombra retornem valores binários. Isso pode ocasionar o surgimento de aliasing nas bordas das sombras. Este trabalho apresenta uma nova abordagem capaz de produzir melhores resultados de suavização que, em conjunto com o algoritmo de PCF (Percentage Closer Filtering), reduz o serrilhado das bordas das sombras através do uso de filtros de menor tamanho. O novo algoritmo estende os conceitos de Shadow Map e de teste de sombra de forma a suportarem múltiplos valores de profundidade. Esta nova abordagem apresenta potencial para implementação em hardware, e também pode ser implementada explorando a programabilidade das recentes placas gráficas. / William’s Shadow Mapping is one of the most efficient hard shadow algorithms. It is simple, robust and can be easily mapped to the actual grapics hardware. It is a two-pass technique. In the first pass a depth buffer (Shadow Map) is created from the light’s view point. In the second pass the final image is rendered from the camera’s view point. In order to decide whether each pixel in the camera’s view is lit or in shadow with respect to the light source, the pixel is transformed into the light space, and tested against the Shadow Map. Shadow maps store a single depth value per cell, leading to a binary outcome by the shadow test, and are prone to produce aliased shadow borders. This work presents a new approach that produces better estimates of shadow percentages and, in combination with percentage closer filtering (PCF), reduces aliasing artifacts using smaller kernel sizes. The new algorithm extends the notions of shadow map and shadow test to support the representation of multiple depth values per shadow map cell, as well as multi-valued shadow test. This new approach has the potential for hardware implementation, but can also be implemented exploiting the programmable capabilities of recent graphics cards.
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Psychological Contract Fulfilment and Innovative Work Behaviours of Employees in Sport-Based Sbes: The Mediating Role of Organisational CitizenshipBarnhill, Christopher R., Smith, Natalie L. 18 December 2018 (has links)
The current study explored the role of psychological contract fulfilment on innovative work behaviours of employees in sport-based small business enterprises (SBEs). Building on literature from sport and non-sport organisational contexts, a model positing a direct linear relationship between psychological contract fulfilment and innovative work behaviours was proposed. Affective commitment and organisational citizenship behaviours were included in the model as partial mediators. The model was tested using a sample of 216 employees from affiliated minor league baseball franchises. Results supported a model where organisational citizenship fully mediated the relationship between psychological contract fulfilments and innovate work behaviours. Affective commitment was predicted by psychological contract fulfilment but was not significantly related to the other variables in the model.
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Optimizing the Physical and Nutritional Environment of Unleached Root-ZonesAdams, Curtis B. 01 May 2010 (has links)
Unleached root-zones represent an environmental ideal by eliminating wasteful leaching of nutrients and water. NASA grows plants in space in unleached root-zones, incorporating polymer-coated fertilizer (PCF) into a ceramic media (Turface or Profile). However, lack of growth productivity in space has led to the need for research to improve the nutritional and physical environment of the root-zone, which is the objective of this research. PCF types are diverse in release characteristics and the effects of temperature and substrate water content have not been well characterized. In spite of widespread use, studies on chemical properties and applied studies to verify soil physical models of ceramic media have been limited. We quantified the release rate of three widely-used types of PCF (Polyon, Nutricote, and Osmocote) in water and in sand over a wide range of temperature (5, 15, 20, 30, and 40ºC). Results indicated that substrate water content had a minimal effect on release rates. Nutricote fertilizers were the most consistent in releasing individual nutrients with temperature and over time. Polyon fertilizers had the slowest release rates relative to the manufacturer's specifications, but a relatively linear response to temperature. Osmocote fertilizers rapidly released nutrients at all temperatures. For more efficient PCF use, we present a comprehensive model that couples models to predict plant growth and PCF nutrient release rates. This model is based on phosphorus release, the nutrient found to be limiting to PCF-fertilized plants. The efficacy of the model to accurately predict PCF application rates was verified with a growth trial. In ceramic media, relative media-sorbed nutrient concentrations were highly variable from bag to bag. Excesses of manganese, boron, magnesium, and sulfur in the media induced nutrient imbalances in plant tissues. Rinsing and soaking procedures on the media helped mitigate these nutrient imbalances. Ceramic media also interacted with added fertilizer ions. Copper, phosphorus, and zinc ions were largely removed from solution by these interactions. We also used plants to extract water from root-zones of ceramic media to characterize plant-available water and water supply dynamics. The results suggest that soil physical models may be used to predict plant-available water in ceramic media.
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Shadow Mapping com múltiplos valores de profundidade / Multiple depth shadow mapsPagot, Christian Azambuja January 2005 (has links)
Um dos algoritmos para cálculo de sombras mais eficientes existentes atualmente é o Shadow Mapping de Williams. Ele é simples, robusto e facilmente mapeável para o hardware gráfico existente. Este algoritmo conta com duas etapas. A primeira é responsável pela geração de um depth buffer (Shadow Map) a partir do ponto de vista da luz. Na segunda etapa a imagem final da cena é gerada a partir do ponto de vista da câmera. De maneira a determinar se os pixels da imagem final estão iluminados ou em sombra, cada pixel é transformado para o espaço da luz e testado contra o Shadow Map. Shadow Maps tradicionais armazenam apenas um valor de profundidade por célula, fazendo com que os testes de sombra retornem valores binários. Isso pode ocasionar o surgimento de aliasing nas bordas das sombras. Este trabalho apresenta uma nova abordagem capaz de produzir melhores resultados de suavização que, em conjunto com o algoritmo de PCF (Percentage Closer Filtering), reduz o serrilhado das bordas das sombras através do uso de filtros de menor tamanho. O novo algoritmo estende os conceitos de Shadow Map e de teste de sombra de forma a suportarem múltiplos valores de profundidade. Esta nova abordagem apresenta potencial para implementação em hardware, e também pode ser implementada explorando a programabilidade das recentes placas gráficas. / William’s Shadow Mapping is one of the most efficient hard shadow algorithms. It is simple, robust and can be easily mapped to the actual grapics hardware. It is a two-pass technique. In the first pass a depth buffer (Shadow Map) is created from the light’s view point. In the second pass the final image is rendered from the camera’s view point. In order to decide whether each pixel in the camera’s view is lit or in shadow with respect to the light source, the pixel is transformed into the light space, and tested against the Shadow Map. Shadow maps store a single depth value per cell, leading to a binary outcome by the shadow test, and are prone to produce aliased shadow borders. This work presents a new approach that produces better estimates of shadow percentages and, in combination with percentage closer filtering (PCF), reduces aliasing artifacts using smaller kernel sizes. The new algorithm extends the notions of shadow map and shadow test to support the representation of multiple depth values per shadow map cell, as well as multi-valued shadow test. This new approach has the potential for hardware implementation, but can also be implemented exploiting the programmable capabilities of recent graphics cards.
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Shadow Mapping com múltiplos valores de profundidade / Multiple depth shadow mapsPagot, Christian Azambuja January 2005 (has links)
Um dos algoritmos para cálculo de sombras mais eficientes existentes atualmente é o Shadow Mapping de Williams. Ele é simples, robusto e facilmente mapeável para o hardware gráfico existente. Este algoritmo conta com duas etapas. A primeira é responsável pela geração de um depth buffer (Shadow Map) a partir do ponto de vista da luz. Na segunda etapa a imagem final da cena é gerada a partir do ponto de vista da câmera. De maneira a determinar se os pixels da imagem final estão iluminados ou em sombra, cada pixel é transformado para o espaço da luz e testado contra o Shadow Map. Shadow Maps tradicionais armazenam apenas um valor de profundidade por célula, fazendo com que os testes de sombra retornem valores binários. Isso pode ocasionar o surgimento de aliasing nas bordas das sombras. Este trabalho apresenta uma nova abordagem capaz de produzir melhores resultados de suavização que, em conjunto com o algoritmo de PCF (Percentage Closer Filtering), reduz o serrilhado das bordas das sombras através do uso de filtros de menor tamanho. O novo algoritmo estende os conceitos de Shadow Map e de teste de sombra de forma a suportarem múltiplos valores de profundidade. Esta nova abordagem apresenta potencial para implementação em hardware, e também pode ser implementada explorando a programabilidade das recentes placas gráficas. / William’s Shadow Mapping is one of the most efficient hard shadow algorithms. It is simple, robust and can be easily mapped to the actual grapics hardware. It is a two-pass technique. In the first pass a depth buffer (Shadow Map) is created from the light’s view point. In the second pass the final image is rendered from the camera’s view point. In order to decide whether each pixel in the camera’s view is lit or in shadow with respect to the light source, the pixel is transformed into the light space, and tested against the Shadow Map. Shadow maps store a single depth value per cell, leading to a binary outcome by the shadow test, and are prone to produce aliased shadow borders. This work presents a new approach that produces better estimates of shadow percentages and, in combination with percentage closer filtering (PCF), reduces aliasing artifacts using smaller kernel sizes. The new algorithm extends the notions of shadow map and shadow test to support the representation of multiple depth values per shadow map cell, as well as multi-valued shadow test. This new approach has the potential for hardware implementation, but can also be implemented exploiting the programmable capabilities of recent graphics cards.
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Raman BiosensorsAli, Momenpour January 2017 (has links)
This PhD thesis focuses on improving the limit of detection (LOD) of Raman biosensors by using surface enhanced Raman scattering (SERS) and/or hollow core photonic crystal fibers (HC-PCF), in conjunction with statistical methods. Raman spectroscopy is a multivariate phenomenon that requires statistical analysis to identify the relationship between recorded spectra and the property of interest. The objective of this research is to improve the performance of Raman biosensors using SERS techniques and/or HC-PCF, by applying partial least squares (PLS) regression and principal component analysis (PCA).
I began my research using Raman spectroscopy, PLS analysis and two different validation methods to monitor heparin, an important blood anti-coagulant, in serum at clinical levels. I achieved lower LOD of heparin in serum using the Test Set Validation (TSV) method. The PLS analysis allowed me to distinguish between weak Raman signals of heparin in serum and background noise.
I then focused on using SERS to further improve the LOD of analytes, and accomplished simultaneous detection of GLU-GABA in serum at clinical levels using the SERS and PLS models. This work demonstrated the applicability of using SERS in conjunction with PLS to measure properties of samples in blood serum. I also used SERS with HC-PCF configuration to detect leukemia cells, one of the most recurrent types of pediatric cancers. This was achieved by applying PLS regression and PCA techniques.
Improving LOD was the next objective, and I was able to achieve this by improving the PLS model to decrease errors and remove outliers or unnecessary variables. The results of the final optimized models were evaluated by comparing them with the results of previous models of Heparin and Leukemia cell detection in previous sections.
Finally, as a clinical application of Raman biosensors, I applied the enhanced Raman technique to detect polycystic ovary syndrome (PCOS) disease, and to determine the role of chemerin in this disease. I used SERS in conjunction with PCA to differentiate between PCOS and non-PCOS patients. I also confirmed the role of chemerin in PCOS disease, measured the level of chemerin, a chemoattractant protein, in PCOS and non-PCOS patients using PLS, and further improved LOD with the PLS regression model, as proposed in previous section.
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A Polypeptide From Chlamys Farreri Inhibits UVB-Induced Hacat Cells Apoptosis via the Apaf-1/Caspase-9 and Smac/Xiap Signaling PathwayLiu, Xiaojin, Wang, Wencheng, Wang, Hongjiang, Zhang, Lanlan, Liu, Leqian, Wang, Yuejun, Wang, Chunbo 01 September 2009 (has links)
A novel marine active polypeptide (PCF), isolated from the gonochoric Chinese scallop, Chlamys farreri, has potential antioxidant and anti-apoptotic activity against ultraviolet irradiation. We investigated whether UVB-induced HaCaT cell apoptosis occurs via the mitochondrial pathways Apaf-1/caspase-9 and Smac/XIAP/caspase-3. We then investigated the molecular mechanisms controlling the anti-apoptotic effect of PCF. Pre-treatment with PCF and caspase-9 inhibitor significantly inhibited UVB-induced apoptosis in HaCaT cells based on a DNA fragmentation assay and Hoechst 33258 staining. The expression of Apaf-1 and the cleavage of procaspase-9 were dose-dependently reduced by 1.42-5.96 mmol/L PCF pretreatment in UVB-irradiated HaCaT cells. This was followed by inhibition of cleavage of procaspase-3, whose activation induced cell apoptosis. Meanwhile, PCF significantly and dose-dependently enhanced the activation of ATPase. Furthermore, we demonstrated that PCF strongly inhibited the release of Smac from the mitochondria to cytosol by reducing the degradation of XIAP dose-dependently. We conclude that the protective effect of PCF against UVB irradiation in HaCaT cells may be attributed to the inhibition of the Apaf-1/caspase-9 and Smac/XIAP/caspase-3 apoptotic signaling pathways.
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