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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
481

Implicit skinning: character skin deformation guided by 3D scalar fields

Vaillant, Rodolphe 02 June 2016 (has links)
In character animation achieving realistic deformations of the skin is a challenging task. Geometric skinning techniques, such as smooth blending or dual-quaternions, are very popular for their high performance but fail to produce convincing deformations. They look too soft compared to human skin deformation at a rigid bone joint. In addition advanced effects such as skin contacts or bulges are not taken into account. Other methods make use of physical simulation or volume control to better capture the skin behavior, yet they cannot deliver real-time feedback. We developed a novel skinning framework called implicit skinning. Our method produces visually plausible deformations in real-time by handling realistic skin contacts and bulges between limbs. Implicit skinning exploits the ability of implicit surfaces to be robustly combined as well as their efficient collision detection. By approximating the mesh by a set of implicit surfaces, we are able to guide the deformation of a mesh character. we can combine the implicit surfaces in real-time, and use the final implicit surface to adjust the position of mesh vertices at each animation step. Since collision detection is very efficient using implicit surfaces we achieve skin contacts between limbs at interactive to real-time frame rates. In this thesis we present the complete implicit skinning framework, that is, the conversion of a mesh character to implicit surfaces, the composition operators and the mesh deformation algorithm on top of the implicit surface. Two deformation algorithms are studied: a fast history dependent algorithm which acts as a post process on top of dual-quaternions skinning and a slower yet more robust history dependent algorithm. / Graduate
482

THE INTERCRATER PLAINS OF MERCURY AND THE MOON: THEIR NATURE, ORIGIN, AND ROLE IN TERRESTRIAL PLANET EVOLUTION

Leake, Martha A. (Martha Alan), Leake, Martha A. (Martha Alan) January 1981 (has links)
The various origins proposed for intercrater plains on Mercury and the Moon lead to divergent thermal, tectonic, and bombardment histories. Relative ages of geologic units and structures place tight constraints on their origin and on the planet's geologic history. Crater statistics, lunar geologic map analysis, and geologic mapping of a quarter of Mercury's surface based on plains units dated relative to crater degradation classes were used to determine relative ages. Such studies provided the basis for deducing the origin of intercrater plains and their role in terrestrial planet evolution. Mercury's extensive intercrater plains span a range of ages contemporaneous with the period of heavy bombardment. Most intercrater plains predate scarp formation and the formation of the hilly and lineated terrain. The age of the latter is identical to that of its probable progenitor, the Caloris basin impact. Post-Caloris plains--smoother in texture, less extensive, and confined to crater depressions--formed as cratering waned and scarp formation progressed. This research indicates that mercurian intercrater plains are volcanic deposits interbedded with ballistically emplaced ejecta and reworked by basin secondaries and smaller impacts. A greater proportion of ejecta may comprise lunar intercrater plains. Neither the lunar nor mercurian intercrater surface is primordial because each preserves pre-plains crateriforms. Ancient volcanism on Mercury is evidenced by widespread plains distribution, structurally controlled deposition, embayment of craters and basins, associated (but tentative) volcanic landforms, losses of small craters, and uncorrelated plains and crater coverage. The limited range of mercurian ejecta reduces the resurfacing potential relative to that of lunar craters. Crater densities are affected by intercrater plains emplacement, additions of secondaries, ancient basin impacts, and target physical properties. "One-plate" thermo-tectonic models best explain the geologic characteristics recognized in this study. Thermal expansion during core formation causes global extension and widespread volcanic extrusions; subsequent cooling and radial contraction form compressional scarps. Younger plains-forming materials issue from magma reservoirs in subsurface tensional zones tapped by impact fractures. The age and stress environment of these volcanic plains suggest a source greater than 40 km depth and a composition different from that of the intercrater plains.
483

Simulation numérique de l'ébullition pour les procédés de trempe industrielle / Numerical simulation of boiling for industrial quenching processes

El Kosseifi, Nadine 27 June 2012 (has links)
Cette thèse porte sur la modélisation de l'ébullition qui joue un rôle important dans les vitessesde refroidissement des pièces, elle possède un volet numérique et un volet expérimental. Lessimulations et les expériences envisagées se situent à deux échelles. A l'échelle d'une ou quelquesbulles de vapeur, il s'agit de faire des simulations multiphasiques très précises en prenant encompte, la tension de surface, les calculs directs d'écoulement à grand nombre de Reynolds, etrendant compte du détachement et de la coalescences des bulles. Des observations expérimentalessont réalisées à la même échelle en contrôlant en surface la nucléation d'une bulle de vapeur àl'aide d'une caméra rapide. Des mesures de champs de vitesse par PIV et de température par twocolor LIF thermometry sont réalisées dans les mêmes conditions. Ceci a permit de confronter lacroissance, la dynamique et les formes des bulles observées et calculés. Les techniques numériquesles plus avancées sont utilisées : Eléments finis stabilisé VMS, level set, adaptation anisotropeet calcul intensif. Les modéles numériques proposés dans cette thèse permettent de passer àl'échelle macroscopique des pièces industrielles en considérant un film de vapeur (ou une phasede mélange liquide vapeur). L'enjeu supplémentaire étant de modéliser la turbulence induite parl'ébullition dans une approche de type CFD. / This thesis focuses on the modelling of boiling that plays an important role on the coolingand heat treatment in quenching processes, it has two components: numerical simulations andexperimental measurements. Both simulations and experiments are envisaged for two scales. Thefirst one concerns small scales: the scale of one or few bubbles. In this case, the focus is put onvery precise numerical simulations for multiphase flows taking into account the surface tension,the direct computations of flows at high Reynolds number, and on reflecting the detachmentand coalescence of bubbles. On that same scale, experimental observations are performed tocontrol, in the volume or at surface, the nucleation of a vapour bubble using a high speedcamera. Measurements of velocity fields by PIV and the temperature by PLIF are realizedunder the same conditions. This will allow us to compare the growth dynamics and shapesof bubbles observed and calculated. Advanced numerical methods are used to fulfil this task:VMS stabilized finite elements, level set, anisotropic adaptation and parallel computing. Thenumerical models proposed in this work are extended and also used to deal with macroscopicscales: at the level of industrial parts considering the vapour films (or a phase of liquid vapourmixture). The additional challenge resides in the modelling of turbulence induced by boiling ina CFD approach.
484

Aspheric/freeform optical surface description for controlling illumination from point-like light sources

Sasián, José, Reshidko, Dmitry, Li, Chia-Ling 25 November 2016 (has links)
We present an optical surface in closed form that can be used to design lenses for controlling relative illumination on a target surface. The optical surface is constructed by rotation of the pedal curve to the ellipse about its minor axis. Three renditions of the surface are provided, namely as an expansion of a base surface, and as combinations of several base surfaces. Examples of the performance of the surfaces are presented for the case of a point light source. (C) 2016 Society of Photo-Optical Instrumentation Engineers (SPIE)
485

Formation et évolution des morphologies de surface des petits corps du système solaire, à partir des images de la sonde spatiale Rosetta / Formation and evolution of the surface morphologies of the small solar system bodies, from Rosetta spacecraft images

Auger, Anne-Thérèse 30 September 2016 (has links)
Résidus du disque primitif dans lequel les planètes se sont formées, les astéroïdes et les comètes fournissent des contraintes sur les processus de formation et d’évolution du système solaire. A partir des images de la mission Rosetta, l’objectif de cette thèse est de caractériser les morphologies de surface de ces petits corps, et d’en étudier les processus qui ont permis de les former et de les faire évoluer.Sur l’astéroïde (21) Lutetia, le relief est contrôlé par les impacts, formant des cratères, des nappes d’éjectas, des fractures et des boulders.Sur la comète 67P, la région Imhotep, située au niveau de l’équateur, présente des terrains lisses et des terrains consolidés très fracturés. Elle est la seule région à présenter des dizaines de structures circulaires de moins de 60 m de diamètre, probablement très anciennes (Ga), que l’on trouve associées à des couches stratifiées de quelques mètres d’épaisseur. Lors du passage au périhélie, des changements de grande envergure se sont produits dans les terrains lisses ; ils pourraient être liés aux contraintes mécaniques opérant dans le sous-sol de la comète. Un type particulier de fractures observé en surface de 67P a aussi été étudié. Ces fractures se joignent pour former des polygones 3 m en moyenne. Ces polygones résultent probablement des fortes variations de température en surface et en subsurface. Plus généralement, les observations et les travaux d’interprétation à partir des données de la mission Rosetta montrent que les morphologies de surface sur 67P sont autant dues à sa formation et à des processus endogènes qu’à des processus exogènes et évolutifs tels que la sublimation ou les contraintes thermiques. / Residuals from the accretion disk in which planets formed, asteroids and comets provide important constraints on the solar system formation and evolution processes. Based on the images from the Rosetta mission, the main objectives of this thesis are to characterize the morphologies at the surface of these small bodies and to study the processes responsible for their formation and evolution.On asteroid (21) Lutetia, the relief is controlled by impacts, forming craters, ejecta blankets, fractures and boulders.On the nucleus of comet 67P, the Imhotep region, located at the equator of the nucleus, presents smooth terrains and consolidated terrains, heavily fractured. It is the only region that shows tens of circular features less than 60 m in size, probably ancient, which we find associated with layers of several meters thick. During the passage at perihelion, major changes occurred in smooth terrains ; they may be linked to mechanical stresses acting in the nucleus subsurface. A particular type of fractures observed at the surface of 67P has also been studied in detail. These fractures join each other in polygons of roughly 3 m in size. These polygons probably result from the strong variations of temperature at the surface and subsurface. More generally, the observations and their interpretation from Rosetta data show that the morphologies at the surface of 67P can result from its formation and endogeneous processes, as well as from exogeneous and evolutionary processes such as the sublimation of ices or thermal stresses.
486

Bioanalytical Applications of Chemically Modified Surfaces

Driscoll, Peter F 15 December 2009 (has links)
"The design and development of chemically modified surfaces for bioanalytical applications is presented. Chemical surface modification is demonstrated to be a method to control surface properties on the molecular level by selecting the appropriate substrate, linking chemistry, and terminal group functionality. These systems utilize spontaneous interactions between individual molecules that allow them to self-assemble into larger, supramolecular constructs with a predictable structure and a high degree of order. Applications investigated in this thesis include: surface patterning, switchable surface wettability, and biological sensor devices that combine surface based molecular recognition, electrochemical detection methods, and microfluidics. A multilayered approach to complex surface patterning is described that combines self-assembly, photolabile protecting groups, and multilayered films. A photolabile protecting group has been incorporated into molecular level films that when cleaved leaves a reactive surface site that can be further functionalized. Surface patterns are created by using a photomask and then further functionalizing the irradiated area through covalent coupling. Fluorophores were attached to the deprotected regions, providing visual evidence of surface patterning. This approach is universal to bind moieties containing free amine groups at defined regions across a surface, allowing for the development of films with complex chemical and physico-chemical properties. Systems with photoswitchable wettability were developed by fabricating multilayered films that include a photoisomerizable moiety, cis-/trans- dicarboxystilbene. When this functionality was incorporated into a multilayered film using non-covalent interactions, irradiation with light of the appropriate wavelength resulted in a conformational change that consequently changed the hydrophobicity of the substrate. Methods were investigated to increase the reversibility of the photoswitching process by creating surface space between the stilbene ligands. Utilizing mixed monolayers for spacing resulted in complete isomerization for one cycle, while the use of SAMs with photolabile groups produced surfaces that underwent isomerization for three complete cycles. A microfluidic device platform for ion sensing applications has been developed. The platform contains components to deliver small volumes of analyte to a surface based microelectrode array and measure changes in analyte concentration electrochemically in an analogous method to that used in conventional electrochemical cells. Crown ether derivatives that bind alkali metal ions have been synthesized and tested as ionophores for a multi-analyte device of this type, and the sensing platform was demonstrated to measure physiological relevant concentrations of potassium ions. Advantages of this design include: high sensitivity (uM to mM), small sample volumes (less than 0.1 mL), multi-analyte capabilities (multiple working electrodes), continuous monitoring (a flow through system), and the ability to be calibrated (the system is reusable). The self-assembled systems described here are platform technologies that can be combined and used in molecular level devices. Current and future work includes: photopatterning of gold and glass substrates for directed cell adhesion and growth, the design and synthesis of selective ion sensors for biological samples, multi-analyte detection in microfluidic devices, and incorporating optical as well as electrochemical transduction methods into sensor devices to allow for greater sensitivity and self-calibration."
487

Description statistique de la surface océanique et mesures conjointes micro-ondes : une analyse cohérente / Statistical description of the sea surface and colocalised microwave measurements : a consistent analysis

Bringer, Alexandra 18 September 2012 (has links)
De plus en plus de données satellitales ou aéroportées acquises au dessus de la surface de la mer sont disponibles notamment dans la gamme micro-ondes. Pour interpréter correctement ces données, il est nécessaire de disposer d'une part d'un modèle de diffusion qui soit capable de prendre en compte l'aspect multi-échelles de la surface de mer et d'autre part une bonne représentation spectrale de la surface de mer. Ces dernières années, plusieurs modèles de diffusion électromagnétiques unifiés (capables de prendre en compte la diffusion électromagnétique pour les petites et grandes vagues) ont été développés sous statistiques gaussiennes de la surface de mer. Cependant, ces modèles sont insuffisants pour interpréter les observations lorsque différents jeux de données (multi-bande et multi-incidence) sont confrontés. Le plus de cette thèse est de progresser dans une modélisation cohérente de ces données radar.La première étape est d'incorporer les aspects non-gaussiens de la surface de mer, connus pour influer significativement sur la section efficace de rétrodiffusion (SER). Cela est réalisé dans le cadre du modèle électromagnétique "Weighted Curvature Approximation » (WCA) en introduisant le kurtosis des pentes et en se limitant à la SER omnidirectionnelle et à la polarisation verticale.Ces corrections permettent une meilleure modélisation de la section efficace radar mais ne sont pas suffisantes pour obtenir un accord avec les données dans toutes les configurations (bande, incidence, vent). Cela suggère une amélioration nécessaire du spectre des vagues courtes, qui fait l'objet de la deuxième partie de ces travaux de recherche.Un nouveau spectre omnidirectionnel est calculé afin d'obtenir une meilleure modélisation de la SER omnidirectionnelle en polarisation verticale tout en respectant des contraintes a priori sur les pentes mesurées par des techniques optiques. Ce spectre s'avère assez semblable au spectre unifié d'Elfouhaily, avec quelques différences notables cependant dans la gamme des échelles décimétriques. / More and more micro-wave data are available from spatial and airborne measurements over sea surface. An accurate backscattering model which is capable of taking the multi-scale aspect of the sea surface into account, is required to model correctly the data as well as a precise sea spectrum. Several unified backscattering models have been developed in recent years under Gaussian statistics. However, these models are not able to give a correct modelization of the backscattered signal when different data sets are studied together. One of the objectives of this study is to improve the modelization of the backscattered signal to get better agreement with the data.The first step of this study is to include non Gaussian statistics into backscattering model as it is well known they have a significant impact on the normalized radar cross section (NRCS). Then, a non Gaussian version of the Weighted Curvature Approximation was developed taking the kurtosis of slopes into account. This work was based only upon vertical polarization.It is then shown that the corrections allow a better agreement with the data but they are not sufficient to get a good estimation of the NRCS for all incidences and electromagnetic frequencies. This induces the hypothesis of a modification of the short wave sea spectrum.Then, a new parametrisation of the omnidirectional sea spectrum is suggested to get a better agreement with the multiband data sets and is based on the spectrum developed by Elfouhaily et al. The new omnidirectional short wave sea spectrum is quite alike the Elfouhaily’s spectrum with some noticeable differences for the decimetric scales.
488

Excitation électrique locale de nanostructures plasmoniques par la pointe d'un microscope à effet tunnel / Local electrical excitation of plasmonic nanostructures with a scanning tunnelling microscope

Rogez, Benoit 16 December 2014 (has links)
Nous utilisons un microscope à effet tunnel (STM) associé à un microscope optique inversé pour l’excitation et la détection des plasmons de surface propagatifs et/ou localisés. L’excitation de ces plasmons est assurée par passage d’un courant tunnel inélastique entre la pointe du STM et la surface d’un film métallique mince (épaisseur de 50 nm) d’or ou d’argent déposé sur une lamelle de verre. Les fuites radiatives des plasmons de surface propagatifs et la lumière émise par les plasmons localisés dans le substrat de verre sont collectées par un microscope optique via un objectif à immersion. Il est alors possible de déterminer à la distribution spatiale et angulaire des émissions issues de ces plasmons de surface excités par STM, ainsi qu’à leur distribution en longueurs d’onde. Dans cette thèse, nous nous sommes intéressés au fonctionnement et à l’émission de lumière sous la pointe d’un microscope à effet tunnel fonctionnant à l’air. Nous montrons que la présence d’eau adsorbée au sein de la jonction tunnel, associée à la boucle d’asservissement du STM induit un mode de fonctionnement oscillant et périodique du STM sans lequel il serait difficile d’exciter les plasmons de surface. Ensuite, nous avons montré qu’il est possible de contrôler la directivité des plasmons de surface propagatifs excités par STM en excitant localement un nanofil d’or déposé sur le film d’or. L’étude détaillée de cette directivité nous a permis de démontrer que, contrairement au cas du nanofil d’or déposé sur verre, un nanofil d’or déposé sur film d’or ne se comporte pas comme un résonateur Fabry Pérot. Nous avons proposé un modèle simple dans lequel le nanofil est assimilé à un réseau linéaire d’antennes. Ce modèle permet de rendre compte des structurations spectrales et spatiales des plasmons de surface sur le film d’or résultant de l’ajout du nanofil d’or. Puis, nous avons étudié le couplage entre des nanofibres organiques fluorescentes (structures excitoniques) et les plasmons de surface propagatifs d’un film métallique d’or ou d’argent sur lequel ces nanofibres sont déposées. Nous avons ainsi montré que (i) la fluorescence de la nanofibre peut exciter des plasmons de surface à la surface du film d’or, (ii) la nanofibre organique agit comme un guide d’onde plasmonique et (iii) qu’il est possible d’injecter des plasmons de surface propagatifs du film excités par STM dans ces modes guidés par la nanofibre. D’autre part, en étudiant la figure d’interférences dans le plan de Fourier, nous avons pu confirmer que l’émission du dipôle sous la pointe STM et les plasmons de surface propagatifs excités par STM sont cohérents, donc issus du même événement tunnel. Enfin, nous discutons les effets du couplage entre des nanocristaux semiconducteurs (quantum dots) individuels et un monofeuillet de graphène. Nous montrons que la présence du graphène réduit d’un facteur ~10 la durée de vie de l’état excité des quantum dots déposés sur graphène par rapport aux quantum dots déposés sur verre. Pour les quantum dots déposés sur graphène, il résulte de cette réduction de la durée de vie de l’état excité, une baisse de l’intensité de fluorescence et une réduction du phénomène de scintillement avec un temps de résidence dans un état brillant globalement plus long que pour les quantum dots déposés sur verre. Les différents résultats obtenus au cours de cette thèse permettent de mieux comprendre l’excitation de plasmons de surface avec un microscope à effet tunnel, le couplage entre nanostructures plasmoniques et le couplage entre une structure plasmonique et une nanostructure excitonique. Ils ouvrent des perspectives intéressantes pour le développement de nanodispositifs hybrides plus complexes liants plasmons et excitons et contrôlés électriquement / We use a scanning tunnelling microscope (STM) to excite propagating and/or localised surface plasmons on a thin metallic film (50 nm thick) made of gold or silver deposited on a glass substrate. The leakage radiation of these STM-excited propagating surface plasmons, and the light emitted by localized plasmons into the glass substrate are collected by an inverted optical microscope equipped with an oil immersion objective. Using this setup, it is possible to image both the spatial and angular distribution of the light emitted into the glass substrate on a cooled-CCD. Sending this light to a spectrometer, it is also possible to obtain the wavelength distribution of these STM-excited plasmons. In this manuscript, we discuss the different operation modes of an STM in air. We show that the thin water layers adsorbed on both the STM tip and sample, along with the STM feedback loop, may give rise to an oscillatory mode of operation. Moreover, this mode turns out to be the most efficient one for plasmon excitation with a STM in air. We then show that, when the STM tip is used to locally excite plasmons on a gold nanowire deposited on a gold film, propagating surface plasmons may be preferentially launched along the nanowire axis. Precise understanding of this directivity allows us to demonstrate that, when deposited on a gold film, gold nanowires do not behave as Fabry-Perot resonators, but may be described quite accurately with a one dimensional antenna array model. With this model, it is thereby possible to explain the complex spatial and spectral characteristics of the STM-excited plasmons on the gold film after the addition of the nanowire. Next, we focus on the coupling between fluorescent organic nanofibres (excitonic nanostructures) and propagating surface plasmons on a metallic film (either gold or silver). We show that when the nanofibres are deposited on the metallic film, (i) their fluorescence can excite propagating surface plasmon, (ii) the nanofibre can act as a plasmonic waveguide, and (iii) it is possible to inject surface plasmons propagating onto the metallic film into the guided plasmonic modes of the nanofibre. Moreover, by studying Fourier space images, we confirmed that the vertical dipole localised under the STM tip and the STM-excited propagating surface plasmons are coherent. We finally study the coupling between individual semiconducting nanocrystals (quantum dots) and a graphene monolayer deposited on a glass substrate. We show that, when deposited on graphene, the fluorescence lifetime of the quantum dots is about 10 times shorter than for the quantum dots deposited on bare glass. This leads to a weaker fluorescence signal and reduced blinking behaviour with longer time spent into a bright state. These results improve our understanding of the STM excitation of surface plasmons. They also provide information on the coupling between plasmonic nanostructures and between plasmonic and excitonic entities. in particular, these results are a promising step toward the conception and the realisation of complex electrically driven hybrid plasmonic/excitonic nanodevices
489

Surface plasmon resonance photonic biosensors based on phase-sensitive measurement techniques.

January 2005 (has links)
Law Wing Cheung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references. / Abstracts in English and Chinese. / Abstract --- p.I / Acknowledgements --- p.V / List of Publications related to this project --- p.VI / Contents --- p.VII / Chapter Chapter 1 --- Introduction --- p.1-1 / Chapter Chapter 2 --- Literature Review / Chapter 2.1 --- Surface Plasmon Waves --- p.2-2 / Chapter 2.2 --- Excitation of Surface Plasmon --- p.2-4 / Chapter 2.2.1 --- Surface Plasmon Coupling Schemes --- p.2-6 / Chapter 2.3 --- Detection Techniques used in SPR sensors --- p.2-13 / Chapter 2.3.1 --- Angular Interrogation --- p.2-14 / Chapter 2.3.2 --- Wavelength Interrogation --- p.2-15 / Chapter 2.3.3 --- Intensity Interrogation --- p.2-16 / Chapter 2.3.4 --- Phase Interrogation --- p.2-16 / Chapter 2.3.5 --- Commercial SPR biosensors --- p.2-18 / Chapter 2.3.6 --- Comparison between Detection Techniques --- p.2-19 / Chapter 2.4 --- Applications of SPR biosensors --- p.2-21 / Chapter Chapter 3 --- Principle of Surface Plasmon Resonance Sensing Technology / Chapter 3.1 --- SPR Phenomenon --- p.3-1 / Chapter 3.2 --- Conditions for Surface Plasmon Resonance --- p.3-5 / Chapter 3.3 --- Wave-vectors --- p.3-7 / Chapter 3.4 --- Surface Plasmon Resonance described by Fresnel's Theory --- p.3-8 / Chapter 3.5 --- Concept of Surface Plasmon Resonance Biosensing --- p.3-10 / Chapter Chapter 4 --- Experiments / Chapter 4.1 --- Highly sensitive differential phase-sensitive surface plasmon resonance biosensor based on Mach-Zehnder configuration --- p.4-1 / Chapter 4.1.1 --- Materials required --- p.4-1 / Chapter 4.1.2 --- Experimental Setup --- p.4-2 / Chapter 4.1.3 --- Principle of Differential Phase Measurement --- p.4-3 / Chapter 4.1.4 --- Photodetector Circuitry --- p.4-6 / Chapter 4.1.5 --- Digital Signal Processing --- p.4-7 / Chapter 4.1.6 --- Polymer based Micro-fluidic System Integrated with SPR Biosensor --- p.4-9 / Chapter 4.2 --- Phase-sensitive Surface Plasmon Resonance Biosensor using the Photoelastic Modulation Technique --- p.4-12 / Chapter 4.2.1 --- Materials required --- p.4-12 / Chapter 4.2.2 --- Experimental Setup --- p.4-13 / Chapter 4.2.3 --- Principle of Photoelastic Modulation Technique and Signal Processing --- p.4-14 / Chapter 4.2.4 --- Operation Principle of Photoelastic Modulator --- p.4-17 / Chapter 4.3 --- Sample Preparations --- p.4-18 / Chapter 4.3.1 --- Glycerin-water Mixtures --- p.4-18 / Chapter 4.3.2 --- "PBS, BSA and BSA antibody" --- p.4-19 / Chapter 4.3.3 --- "RPMI, Trypsin, Cells and SDS" --- p.4-20 / Chapter Chapter5 --- Results amd Discussions / Chapter 5.1 --- Experimental setup I: Highly sensitive differential phase-sensitive surface plasmon resonance biosensor based on Mach-Zehnder configuration --- p.5-1 / Chapter 5.1.1 --- Measuring various glycerin-water concentration mixture with silver-gold sensing layer --- p.5-1 / Chapter 5.1.2 --- Comparison between the sensitivity of our setup and reported setup based on phase detection --- p.5-4 / Chapter 5.1.3 --- Discussion on 0.01° system resolution --- p.5-7 / Chapter 5.1.4 --- Experiment on monitoring BSA-BSA antibody binding reaction --- p.5-9 / Chapter 5.1.5 --- Matching oil and glass slide --- p.5-11 / Chapter 5.1.6 --- Experiments on monitoring BSA-BSA antibody binding reaction with integrated microfluidic system --- p.5-12 / Chapter 5.1.7 --- Experiment on observing cell adhesion properties on gold surface under the influence of trypsin --- p.5-14 / Chapter 5.1.8 --- Discussion on the non-specific binding between trypsin and gold surface --- p.5-16 / Chapter 5.1.9 --- Modifying the gold surface with BSA layer --- p.5-17 / Chapter 5.1.10 --- Experiment on observing cell adhesion properties on the gold surface under the influence Sodium Dodecyl Sulfate (SDS) --- p.5-18 / Chapter 5.2 --- Experimental setup II: Phase-sensitive surface plasmon resonance biosensor using the photoelastic modulation technique --- p.5-21 / Chapter 5.2.1 --- Measurement on difference glycerin-water concentration mixture --- p.5-21 / Chapter 5.2.2 --- Experiment on monitoring BSA-BSA antibody binding reaction --- p.5-23 / Chapter Chapter 6 --- Conclusions and Future Works / Chapter 6.1 --- Conclusions --- p.6-1 / Chapter 6.2 --- Future Works --- p.6-2 / References --- p.R-1 / Appendix / Chapter A. --- Phase Extraction Routine written by Matlab --- p.A-1 / Chapter B. --- Mathematical expressions for calculating the phase angle in the experiment of SPR biosensor using the Photoelastic Modulation Technique --- p.A-6 / Chapter C. --- Relationship between Concentration and Refractive Index of Glycerin-Water Mixture --- p.A-11 / Chapter D. --- Physical Properties of Bovine Serum Albumin --- p.A-12 / Chapter E. --- Simulation Curve written by Matlab --- p.A-13
490

Surface plasmon enhanced effects in photonic biosensors. / CUHK electronic theses & dissertations collection

January 2008 (has links)
Detection of oligonucleotide target has been performed with a sandwich assay scheme. We compare the detection performance of strategies using probe oligonucleotide with or without gold nanoparticles (Au-NPs, 20nm) capped on 3'. Our experimental results reveal that while the DNA detection implemented with NIS can provide high sensitivity, both dynamic range and detection limit can be amplified with the aid of Au-NPs on 3' of the probes. The current detection limits of NIS with and without Au-NPs are 0.4 femtomole and 1 nanomole respectively. (Abstract shortened by UMI.) / Finally, this work presents a systematic study of the surface-enhanced Raman-scattering (SERS) properties of nanoparticle island substrates (NIS) and their application for oligonucleotide target detection. To effectively implement SERS on NIS and identify an optimal condition for DNA detection, the relationship between extinction maximum (lambdamax) and SERS enhancement factor (EF) will be explored in detail. This work demonstrates high S/N ratio SERS spectra can be achieved with NIS that has lambdamax located within a spectral window (∼60nm) defined by the excitation wavelength (514nm) and the scattered Raman wavelength. The highest EF measured is about 4x10 8 with a thickness of Ag being 50 A. / In addition, a surface plasmon enhanced ellipsometry (SPEE) biosensor scheme based on the use of a photoelastic modulator (PEM) has been explored. We showed that the polarization parameters of a laser beam, tan psi, cos Delta and ellipse orientation angle &phis;, can be directly measured by detecting the modulation signals at the 1st and 2nd harmonics of the modulation frequency under a certain birefringence geometry. This leads to an accurate measurement of refractive index variations within the evanescent field region close to the gold sensor surface, thereby enabling biosensing applications. Our experimental results confirm that the new scheme offers a decent detection limit of 2x10-7 refractive index unit (RIU) or 5ng/ml of biomolecule solute concentration without any compromise in dynamic range. / We have demonstrated that the sensitivity limit of intensity-based SPR biosensors can be enhanced when we combine the contributions from phase with that of amplitude instead of just detecting the amplitude or phase variation only. Experimental results indicate that an enhancement factor of as much as 20 times is achievable, yet with no compromise in measurement dynamic range. While existing SPR biosensor systems are predominantly based on the angular scheme, which relies on detecting intensity variations associated with amplitude changes only, the proposed scheme may serve as a direct system upgrade approach for these systems. / We have developed a novel design of multi-pass surface plasmon resonance (SPR) biosensor with differential phase interrogation based on multi-pass interferometry. This new configuration provides an intrinsic phase amplification effect of over two-fold by placing the SPR sensor head in a signal arm of the interferometer so that the interrogating optical beam will traverse the sensor surface infinite number of times. Experimental interferometers based on the Michelson and Fabry-Perot configurations have been employed to experimentally verify this amplification effect through the comparison with the Mach-Zehnder configuration. Results obtained from the salt-water mixtures, antibody-antigen, and protein-DNA binding reaction have confirmed the expected phase measurement enhancement. / Yuan, Wu. / Adviser: H. P. Ho. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3582. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 115-132). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

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