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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.
251

Femtosecond-Laser-Enabled Fiber-Optic Interferometric Devices

Yang, Shuo 11 November 2020 (has links)
During the past decades, femtosecond laser micro-fabrication has gained growing interests owing to its several unique features including direct and maskless fabrication, flexible choice of materials and geometries, and truly three-dimensional fabrication. Moreover, fiber-optic sensors have demonstrated distinct advantages over traditional electrical sensors such as the immunity to electromagnetic interference, miniature footprint, robust performance, and high sensitivity. Therefore, the marriage between femtosecond laser micro-fabrication and optical fibers have enabled and will continue to offer vast opportunities to create novel structures for sensing applications. This dissertation focuses on design, fabrication and characterization of optical-fiber based interferometric devices for sensing applications. Three novel devices have been proposed and realized, including point-damage-based Fiber Bragg gratings in single-crystal sapphire fibers, all-sapphire fiber-tip Fabry-Pérot cavity, and in-fiber Whispering-Gallery mode resonator / Doctor of Philosophy / Optical fibers are an optical platform with cylindrical symmetry with overall diameter typically within 50 to 500 μm. The miniature footprint and large aspect ratio make it attractive in sensing applications, where intrusion, flexibility, robustness and small size are key design parameters. Beyond that, fiber-optic sensors also possess distinct operational advantages over traditional electrical sensors such as high sensitivity, immunity to electromagnetic interference (EMI), and fully distributed deployment. Owing to the above advances, fiber-optic sensors have been one of the key technologies in the broader sensing field for the past decades. However, the unique cylindrical shape of optical fiber makes it naturally less compatible to those well-developed fabrication technologies in the current sophisticated semiconductor industry. During the past decades, the possibility of three-dimensional (3D) writing inside transparent materials with tightly focused ultrafast laser pulses has attracted attention widely among the academy as well as the industry. Therefore, the marriage between ultrafast laser micro-fabrication and optical fibers have enabled and will continue to offer vast opportunities to create novel structures for sensing applications. This dissertation focuses on design, fabrication and characterization of optical-fiber based interferometric devices for sensing applications. Three novel devices have been proposed and realized, including point-damage-based Fiber Bragg gratings in single-crystal sapphire fibers, all-sapphire fiber-tip Fabry-Pérot cavity, and in-fiber Whispering-Gallery mode resonator.
252

The Waltz on the Seine

Kang, Jennifer J. 10 November 2000 (has links)
The desire to recognize and celebrate a forgotten artist and her work presents an opportunity for an investigation into the meeting of art and architecture. The dialogue between these two entities highlights the complexity of exhibiting works of art within a space of architectural integrity. The challenge is to successfully address both the art and the architecture in order to achieve a relationship that is mutually beneficial and equally powerful. This thesis investigates the transcendent themes created in such a dialogue. An innovative approach creates opportunities for extraordinary spatial experiences of the architecture and the artwork itself while addressing the challenges proposed by the site, one that has tremendous historical and cultural significance. The ultimate goal is a place where the architectural conditions provide a canvas for the acknowledgment and celebration of the artistic endeavors. / Master of Architecture
253

Spectroscopy and dynamics of colloidal particles and systems at interfaces

Moore, Lee James January 2012 (has links)
This thesis presents an investigation of the dynamic properties of wide range of interfacial systems, from colloidal particles in solution, through the realm of aerosols and onto studies of molecular adsorption at an interface. The primary experimental technique utilized is optical tweezers. An exploration of the history of the use of radiation pressure to manipulate matter is presented, followed by an introduction to how optical tweezers work. Some of the more advanced methods of tweezing are discussed, with an emphasis on the use of spatial light modulators (SLMs) to realise dynamic holographic optical tweezers (DHOTs), an example of which has been constructed within our laboratory using off-the-shelf optical components, and combined with a spectrometer to facilitate high resolution spectroscopic studies of microscopic systems. The spectroscopic analysis of microparticles is greatly enhanced by optical feedback generated when the wavelength of light utilized is an integer number of wavelengths around the circumference of the microsphere. Enhanced signal occurs at these wavelengths, termed whispering gallery modes (WGMs). The absolute position of these resonances depends strongly upon the shape, size and refractive index of the particle, and is predicted by Mie theory. A discussion of the concepts behind Mie theory, as well as how to use an experimental WGM spectrum to deduce the size and composition of a microparticle, is provided. This technique is then put to use in a detailed study on the properties of single aerosols, comprised of sodium chloride solution, and generated using a handheld medical nebulizer. Studies have been carried out on both evaporating and growing droplets trapped with a Gaussian beam; in the latter case, periods of size stability are observed, owing to resonant absorption of radiation at the trapping laser wavelength. The SLM can be used to change the trapping laser to a Laguerre-Gaussian (LG) mode, and an investigation of how this affects the dynamics of the droplet is presented. It is found that the use of LG modes with $ellgeq10$ produced Raman spectra with significantly more intense WGMs, and also suppressed droplet evaporation. Through observations made with fluorescent polystyrene microspheres, it is argued that the LG modes are more efficient at coupling into WGMs of the droplets. Leading on from these experiments on salt water droplets, experiments have been conducted using ionic liquids (ILs). These fluids have many fascinating properties and potential applications. The optical trapping of droplets comprised of aqueous solutions of the ionic liquid ethylammonium nitrate (EAN) and water has been demonstrated for the first time. These droplets are analysed spectroscopically by illuminating them with the output from a broadband LED; WGMs that are observed in the backscattered light are used to determine their size and composition. The response of the droplets to conditions of varying relative humidity has also been investigated. In order to characterise the relative humidity experienced by both the salt water and IL droplets, the concentration of water vapour within the trapping cells has been measured using diode laser absorption spectroscopy. The spatially modulated laser beam is then utilized in a different fashion; instead of optically tweezing a sample, a low numerical aperture objective lens is utilized to focus the laser onto the surface of a gold coated microscope slide. When a colloidal sample is placed on this surface, the thermal gradients cause the particles to form two dimensional crystals. The SLM is utilized to form multiple nucleation sites, and the dynamics of the crystals are directly observed in real time using video microscopy. It is found that grain rotation-induced grain coalescence (GRIGC) occurs, with the rotation of both crystals before coalescence. Control over the grain size is achieved by altering the separation of the laser spots, and shows that the time scale for grain boundary annealing in our system is in good agreement with theoretical expressions formulated for nanocrystal growth. Finally, as a complimentary technique to the microparticle spectroscopy previously discussed, a bulk interface is probed by using evanescent wave broadband cavity enhanced absorption spectroscopy (EW-BBCEAS) specifically to study the adsorption of cytochrome c (cyt c) to a fused silica surface. Visible radiation from a supercontinuum source is coupled into an optical cavity consisting of a pair of broadband high reflectivity mirrors, and a total internal reflection (TIR) event at the prism/water interface. Aqueous solutions of cyt c are placed onto the TIR footprint on the prism surface and the subsequent protein adsorption is probed by the resulting evanescent wave. The time integrated cavity output is directed into a spectrometer, where it is dispersed and analysed. The broadband nature of the source allows observation of a wide spectral range (ca 250 nm in the visible). The system is calibrated by measuring the absorption spectra of dyes of a known absorbance. Absorption spectra of cyt c are obtained for both S and P polarized radiation, allowing information about the orientation of the adsorbed protein to be extracted.
254

Pamětní kniha neboli Erbovník aneb Wappenbuch úředníků zemského soudu jako prostředek sebeprezentace šlechty v raném novověku / Memorial Book alias Armorial Book or Wappenbuch of officials of Lands Court as means of self-presentation of nobility in Early Modern Age

Kocourková, Eva January 2014 (has links)
Aim of this diploma thesis is both a comparison of three manuscripts which are copies of paintings of coats of arms of officials of the Land Court, which decorate spaces at Prague Castle, where Land Court met. Furthermore identification of the individual persons and coats of arms and their perception in the context of self-presentation of the nobility of Early Modern and finally prosopography of officials whose coats of arms are shown in the manuscripts.
255

Barokní znakové galerie. Heraldická reprezentace šlechty, duchovenstva a měšťanstva, její interpretace a možnosti využití / The baroque heraldic gallery of coats of arms. Heraldic representation of nobility, clergy and burghers, its interpretation and application possibilities

Oulík, Jan January 2012 (has links)
This article focuses on Baroque heraldry, specifically the phenomenon of galleries of coats of arms in the Bohemian lands during the post-White Mountain period. Using auxiliary historical sciences methods, three sets of coats of arms from 1660-1690 are analysed: 1. Heraldic coats of arms and insignia of benefactors on sixteen paintings of the Saint Wenceslas series in the Basilica of St. Wenceslaus in the pilgrimage area of Stará Boleslav near Prague; 2. A set of three painted coats of arms in stucco cartouches on the triumphal arch of the Chapel of the Virgin Mary and St. Charles Borromeo in the former Vlašský Hospital in Prague's Lesser Town; 3. Heraldic coats of arms and insignia on ten wooden plinths of statues of Bohemian patrons in the archdeanery church of the Assumption of the Virgin Mary in Tachov. The article yields a series of named sets of coats of arms, and the identification of most persons to whom they belonged to, including a comparison with coats of arms presented in other sources (seals, designs on deeds for coats of arms, old prints). With the placement into a wider historical context and an analysis of the donor structure, the article also points to the composition of the elite at that time, stemming from a range of higher and lower nobility, clergy and burghers, and to the need to make...
256

Galerie Vincence Kramáře / Vincenc Kramar Gallery

Micka, Alois January 2013 (has links)
5 ABSTRACT The subject of this diploma work is the documentation and presentation of program contents of the new exhibition at "Svaz československých výtvarných umělců" in Prague 6 Dejvice between the years 1964 to 1972, which carried the name of Czech theoretic artist, Vincenc Kramář. This diploma work is divided into three distinct parts. The first part focuses on the founders of the gallery and briefly about the personality of Vincenc Kramář. The second part is devoted to the work posted in the gallery between 1964 and 1972. The final part of the work explores the question of what place and position the Vincenc Kramář Gallery holds in comparison to other galleries during the same period. The introduction of the work comments on society and politics of the 1960s in the context of "fine arts", which was an era marked by the official tendencies of the socialist realism of the decade previous. The introduction also includes the process of creating and building a new exhibition hall into this era. The first chapter is dedicated to the patron of the gallery, Vincenc Kramář, and to the founding figures of this new gallery including František Doležal, commissioner and chairman of the exhibition committee; František Rocman, typographer; secretaries and co-founders of the gallery Antonín Kulda, Alena...
257

New Orleans Auction Galleries: An Internship Academic Report

Connors, Grace Elizabeth 01 December 2015 (has links)
This internship academic report is the result of a 480--‐hour internship at New Orleans Auction Galleries completed from February--‐September 2015. New Orleans Auction Galleries is a for--‐profit arts organization located in the Arts District of New Orleans, Louisiana. During my internship, I worked closely with the Art Department and Office Administration, as well as preview receptions andauctions. This experience provided me with a valuable education of the inner workings of New Orleans Auction Galleries from its day--‐to--‐day operations to its vision as an organization. His report begins with the history and goals of New Orleans Auction Galleries and moves forward with discussing the structure of the organization as it stands today, a SWOT analysis, best practices, recommendations, and concludes with my final thoughts.
258

S dětmi do galerie. Procesy tvorby edukačního programu v nezávislé galerii současného umění / Working with children in a gallery: Developing an educative program for an independent gallery space of contemporary art

Smetanová, Barbora January 2018 (has links)
The study deals with the creation of gallery educational programs based on cooperation with artists and curators. The text is divided into two parts. In the theoretical part we try to define theoretical discursive field of art, galleries and gallery education. In the practical part we design gallery educational programs in cooperation with the artists and verify them with the children's group. KEYWORDS gallery education, discourse, visual culture, art work, contemporary art
259

Microresonateurs optiques à etat liquide et microfluidique digitale : applications aux lasers à colorant en gouttes pour les laboratoires-sur-puce / Liquid state optical resonators and digital microfuidics : applications to droplet dye lasers for lab-on-chips

Aubry, Guillaume 18 March 2011 (has links)
L’objectif de ce travail porte sur l’étude et la réalisation de résonateurs optiques à état liquide en microfluidique digitale. Les gouttes sphériques constituent des résonateurs à mode de galerie, dans lesquels la lumière peut être piégée par réflexion totale interne. A l’échelle microscopique, elles exhibent des propriétés optiques remarquables. Leurs facteurs de qualité très élevés en font notamment des objets propices à l’étude de phénomènes optiques non linéaires, tel l’effet laser, et leur confèrent un potentiel certain en spectroscopie. Par ailleurs, la microfluidique digitale, qui a trait aux systèmes multiphasiques dans des microcanaux artificiels, offre une grande liberté de manipulation des microgouttes : génération au kHz, transport, encapsulation, fusion, division, stockage, triage… Aussi, pour les laboratoires-sur-puce, le développement de ces microgouttes en cavités résonantes constitue une opportunité d’intégrer des outils d’analyse optique capables de sonder des échantillons allant du picolitre au nanolitre.Après un exposé des propriétés optiques des résonateurs à modes de galerie, ce mémoire rapporte les travaux réalisés. Une présentation des méthodes de microfabrication et du montage expérimental précède l’étude de la génération de cavités optiques liquides en dynamique. Ces cavités résonantes sont ensuite appliquées aux sources lasers microfluidiques. En particulier, un effet laser a été mis en évidence dans des microgouttes sphériques d’éthylène glycol contenant de la rhodamine 6G. Enfin, une ouverture sur des systèmes couplant microgouttes et cavités Fabry-Perot présente d’autres perspectives telles que l’analyse de gouttes passives en intravité laser ou bien la commutation rapide de la longueur d’onde d’émission de lasers microfluidiques monomodes. / The purpose of this work is to study and realize liquid state optical resonators in digital microfluidics. Spherical droplets may behave as whispering gallery mode resonators, in which light is trapped by total internal reflections. At the microscopic scale, they exhibit outstanding optical properties. Their high quality factors make them attractive for studying non-linear optical phenomena, such as lasing, and for spectroscopy. In another field of research, digital microfluidics, that deals with multiphase fluid systems in artificial microchannels, also involves microdroplets. It offers a high degree of freedom in handling microdroplets: kHz generation, transport, encapsulation, fusion, division, stockpiling, sorting… Therefore, in lab-on-chip systems, turning microdroplets into resonant microcavities constitutes an opportunity for integrating optical analysis tools that can probe picoliter to nanoliter samples.After a review of the optical properties of whispering gallery mode resonators, this thesis reports the experimental results. A presentation of the methods of microfabrication and of the experimental bench top precedes the study of the dynamic generation of liquid optical microcavities. Then, these resonant cavities are applied to microfluidic laser sources. In particular, lasing effect has been demonstrated in spherical microdroplets of ethylene glycol and rhodamine 6G. Finally, an opening towards systems that combine microdroplets and Fabry-Perot cavities presents other perspectives such as the analysis of passive droplets in laser intacavity or the capability of fast switching the output wavelength of single mode microfluidic dye lasers.
260

L'orfèvrerie québécoise dans le contexte muséal : une relecture contemporaine de la Collection Henry Birks d'orfèvrerie canadienne

Blain, Marie-Pier 08 1900 (has links)
No description available.

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