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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.
261

Études expérimentales de dispositifs intégrés à base de micro-résonateurs à mode de galerie en verres actifs / Experimental studies of integrated devices based on whispering gallery mode micro-resonators in active glasses

Rasoloniaina, Alphonse 14 February 2014 (has links)
Les microrésonateurs à mode de galerie passifs à base de cristal ou de verre fabriqués par la méthode de fusion possèdent un facteur de qualité limité à quelques 10E8. Ceci est généralement dû à la contamination de la surface du résonateur lors de sa fusion. Dans ces travaux, nous proposons de contourner cette limitation en utilisant des microrésonateurs actifs pour compenser les pertes. Afin de caractériser les microrésonateurs actifs de très haut facteur de qualité ainsi obtenu, nous nous appuyons sur la méthode CRDM (Cavity Ring Down Measurement). Cette méthode interférométrique est d'une part bien adaptée à la caractérisation de résonateurs de très haut facteur de qualité et d'autre part elle permet de remonter de manière univoque aux facteurs de qualité intrinsèque Qo et extrinsèque Qe du résonateur. Dans un régime de compensation de pertes, nous avons pu atteindre tous les régimes de couplage et obtenus des facteurs de qualité intrinsèques excédant les 10E10. En régime d'amplification sélective, nous avons démontré expérimentalement que l'on pouvait obtenir des gains élevés allant jusqu'à 33 dB et des retards de groupe excédant 2,3 µs dans ces microrésonateurs actifs. Ces microrésonateurs de très haut facteur de qualité et de très haute finesse peuvent présenter un couplage modal se manifestant par un doublet de résonances. Une confrontation théorie/expérience avec la méthode CRDM permet de mesurer un écart très faible entre les doublets. Par ailleurs, ces microrésonateurs présentant un fort confinement spatial et une forte surtension, sont propices à l'observation d'effets non-linéaires. Une modélisation intégrant l'effet thermique et l'effet Kerr a été réalisée. Une confrontation théorie/expérience nous a permis d'estimer la puissance réellement injectée dans le mode ainsi qu'à estimer le volume du mode. / Glass-based whispering gallery mode (WGM) microresonators are easy to produce by melting techniques. However, they suffer from surface contamination which limits their long term quality factor to only about 10E8. In this thesis, we show that an optical gain provided by erbium ions can compensate for residual losses. The optical characterization method is based on frequency-swept “Cavity-Ring-Down-Measurement”. This method can fully describe the linear properties of microcavities such as coupling regime and group delay. In compensation loss regime we demonstrate that it is possible to control the coupling regime of an ultrahigh Q-factor microresonator from undercoupling to spectral selective amplification. Under the selective amplification regime, we obtain an internal Q-factor exceding 10E10. In selective amplification, we experimentally show that it is possible to obtain high amplification up to 33 dB and a high group delay. The microresonators with high Q-factor and high finesse could give rise to a modal coupling which exhibits a splitting of the resonance in the transmission. A characterization of this phenomenon with the cavity ring down method was realized. Moreover, these microresonators, are conducive to the non-linear effect observation. A model incorporating the thermal effect and the Kerr effect has been achieved. Confrontation between theory and experiment allowed us to estimate the real optical power injected into the mode as well as estimating the mode volume.
262

Cutting Into Relief

Bass, Matthew L. 20 March 2013 (has links)
The following is an examination of the ideas and decisions that went into an art exhibition held in gallery 303 of the Harris Fine Art Center February 1-13, 2013. The exhibition explores the relationships of the artwork, artist, viewer, and space. The catalyst for the above mentioned exploration is a process of making art using linoleum relief printing. The subject of the artwork is an in-depth examination of the material and printing process. It is my contention that such a close look at the art making process reveals the attitudes and decisions that we make with any human endeavor.
263

Konsthallar och gallerier på nätet : En retorisk analys om konsten att övertyga om (samtids)konst / Art galleries on the Internet : A rhetorical analysis about the art to convince about (contemporary) art

Lindholm, Viktoria January 2008 (has links)
Uppsatsen undersöker retoriken runt konst på fyra konstverksamheters hemsidor. Konsthallarna och gallerierna som undersöks är alla belägna på landsbygden eller i mindre samhällen i Sverige. Dessa är Bjurbäcks konsthall, Virserums konsthall, Neon Gallery samt Galleri Astley. De frågor som ställs till materialet är: Vilken konst är det som presenteras och hur lyfts den fram? Vilka retoriska medel använder man sig av, och vem vänder man sig till? I vilka sammanhang presenteras konst? Vilken relation och vilket synsätt till konst förmedlas? Vilken relation till platsen och miljön där konsthallen och galleriet är belägen förmedlas? För att undersöka hur konstverksamheternas retorik är upplagd på hemsidorna har framförallt de klassiska begreppen ethos, logos och pathos fungerat som analysverktyg så som de används i metoden retorikanalys. Retorikanalys menar Brigitte Mral är en användbar metod som kan hjälpa oss att försöka förstå och tolka budskap. Hur bilder och design på olika sätt samspelar med texten har också varit viktigt att undersöka. Den redovisade analystexten i uppsatsen visar på samband mellan bild- och textretorik och hur dessa tillsammans bildar en gemensam retorik. Teorier som används i uppsatsen ger perspektiv på begreppet konst. Förutom filosofiska definitionsförsök av vad konst är eller kan vara, presenteras här föreställningar om konst i relation till tre områden: företag, teknologi och media. Ytterligare en teoretisk ingång som tolkats som relevant i uppsatsen, är att se på den lokala platsen i relation till nationen, EU och den globala världen. Resultatet i uppsatsen visar att de fyra konstverksamheterna valt olika sätt att marknadsföra konst på sina respektive hemsidor, men trots detta är retoriken för samtidskonst ofta ganska traditionell. Hemsidan kan uppfattas som en kombinerad informations- och marknadsföringskanal. Den måste kunna fungera för olika målgrupper, såsom samarbetspartners, finansiärer, skolor, med mera. Detta är något som problematiseras i uppsatsen. / The essay examines the rhetoric around art on four art galleries´ homepages. The art galleries that are examined are all located on the countryside or in smaller towns in Sweden. With their Swedish names the examined objects are the following: Bjurbäcks konsthall, Virserums konsthall, Neon Gallery and Galleri Astley. The questions that are set to the material are: What kind of art is presented and how is it conveyed? Which rhetorical instruments are used and which target groups do they aim at? In which context is art presented? Which relation to art and which perspective on art is mediated? Which relation to the site and the environment where the art galleries are located is conveyed? The classical concepts ethos, logos and pathos - as they are used in Rhetorical analysis - have been used as instruments to investigate how the rhetoric about art is applied. Brigitte Mral means that Rhetorical analysis is a useful method to help us understand and interpret messages. How pictures and design in different ways interplay with the text, has also been important to investigate. The presented analysis in the essay shows the connections between text- and visual rhetoric, and how these elements together form a common rhetoric. Theories that are used in the essay give perspectives on the concept of art. Definitions about what art can be are presented mainly from a philosophical perspective. But the idea of art is also presented in relation to three other spheres such as companies, technology and the media. Another theoretical input interpreted as relevant in the essay, is the perspective on the local place in relation to the nation, EU and the global world. The result in the essay shows that the four art galleries have chosen different ways to market art on their respective homepages. Despite this is the rhetoric on contemporary art mainly traditional. The homepage can be considered as a combined information- and marketing channel. It must function for different target groups such as collaborative partners, financiers, schools, etc. This is examined and discussed in the essay.
264

Theory, Design and Development of Resonance Based Biosensors in Terahertz and Millimeter-wave

Neshat, Mohammad January 2009 (has links)
Recent advances in molecular biology and nanotechnology have enabled scientists to study biological systems at molecular and atomic scales. This level of sophistication demands for new technologies to emerge for providing the necessary sensing tools and equipment. Recent studies have shown that terahertz technology can provide revolutionary sensing techniques for organic and non-organic materials with unprecedented accuracy and sensitivity. This is due to the fact that most of the macromolecules have vibrational and/or rotational resonance signatures in terahertz range. To further increase the sensitivity, terahertz radiation is generated and interacted with the bio-sample on a miniaturized test site or the so-called biochip. From the view point of generation and manipulation of terahertz radiation, the biochip is designed based on the same rules as in high frequency electronic chips or integrated circuits (IC). By increasing the frequency toward terahertz range, the conventional IC design methodologies and analysis tools fail to perform accurately. Therefore, development of new design methodologies and analysis tools is of paramount importance for future terahertz integrated circuits (TIC) in general and terahertz biochips in particular. In this thesis, several advancements are made in design methodology, analysis tool and architecture of terahertz and millimeter-wave integrated circuits when used as a biochip. A global and geometry independent approach for design and analysis of the travelling-wave terahertz photomixer sources, as the core component in a TIC, is discussed in details. Three solvers based on photonic, semiconductor and electromagnetic theories are developed and combined as a unified analysis tool. Using the developed terahertz photomixer source, a resonance-based biochip structure is proposed, and its operation principle, based on resonance perturbation method, is explained. A planar metallic resonator acting as a sample holder and transducer is designed, and its performance in terms of sensitivity and selectivity is studied through simulations. The concept of surface impedance for electromagnetic modeling of DNA self-assembled monolayer on a metal surface is proposed, and its effectiveness is discussed based on the available data in the literature. To overcome the loss challenge, Whispering Gallery Mode (WGM) dielectric resonators with high Q factor are studied as an alternative for metallic resonator. The metallic loss becomes very high at terahertz frequencies, and as a result of that planar metallic resonators do not exhibit high Q factor. Reduced Q factor results in a low sensitivity for any sensor using such resonators. Theoretical models for axially and radially layered dielectric resonators acting on WGM are presented, and the analytical results are compared with the measured data. Excitation of WGM through dielectric waveguide is proposed, and the critical coupling condition is explained through analytical formulation. The possibility of selecting one resonance among many for sensing application is also studied both theoretically and experimentally. A high sensitivity sensor based on WGM resonance in mm-wave and terahertz is proposed, and its sensitivity is studied in details. The performance of the proposed sensor is tested for sensing drug tablets and also liquid droplets through various measurements in mm-wave range. The comprehensive sensitivity analysis shows the ability of the proposed sensor to detect small changes in the order of 10−4 in the sample dielectric constant. The results of various experiments carried out on drug tablets are reported to demonstrate the potential multifunctional capabilities of the sensor in moisture sensing, counterfeit drug detection, and contamination screening. The measurement and simulation results obtained in mm-wave hold promise for WGM to be used for sensing biological solutions in terahertz range with very high sensitivity.
265

Theory, Design and Development of Resonance Based Biosensors in Terahertz and Millimeter-wave

Neshat, Mohammad January 2009 (has links)
Recent advances in molecular biology and nanotechnology have enabled scientists to study biological systems at molecular and atomic scales. This level of sophistication demands for new technologies to emerge for providing the necessary sensing tools and equipment. Recent studies have shown that terahertz technology can provide revolutionary sensing techniques for organic and non-organic materials with unprecedented accuracy and sensitivity. This is due to the fact that most of the macromolecules have vibrational and/or rotational resonance signatures in terahertz range. To further increase the sensitivity, terahertz radiation is generated and interacted with the bio-sample on a miniaturized test site or the so-called biochip. From the view point of generation and manipulation of terahertz radiation, the biochip is designed based on the same rules as in high frequency electronic chips or integrated circuits (IC). By increasing the frequency toward terahertz range, the conventional IC design methodologies and analysis tools fail to perform accurately. Therefore, development of new design methodologies and analysis tools is of paramount importance for future terahertz integrated circuits (TIC) in general and terahertz biochips in particular. In this thesis, several advancements are made in design methodology, analysis tool and architecture of terahertz and millimeter-wave integrated circuits when used as a biochip. A global and geometry independent approach for design and analysis of the travelling-wave terahertz photomixer sources, as the core component in a TIC, is discussed in details. Three solvers based on photonic, semiconductor and electromagnetic theories are developed and combined as a unified analysis tool. Using the developed terahertz photomixer source, a resonance-based biochip structure is proposed, and its operation principle, based on resonance perturbation method, is explained. A planar metallic resonator acting as a sample holder and transducer is designed, and its performance in terms of sensitivity and selectivity is studied through simulations. The concept of surface impedance for electromagnetic modeling of DNA self-assembled monolayer on a metal surface is proposed, and its effectiveness is discussed based on the available data in the literature. To overcome the loss challenge, Whispering Gallery Mode (WGM) dielectric resonators with high Q factor are studied as an alternative for metallic resonator. The metallic loss becomes very high at terahertz frequencies, and as a result of that planar metallic resonators do not exhibit high Q factor. Reduced Q factor results in a low sensitivity for any sensor using such resonators. Theoretical models for axially and radially layered dielectric resonators acting on WGM are presented, and the analytical results are compared with the measured data. Excitation of WGM through dielectric waveguide is proposed, and the critical coupling condition is explained through analytical formulation. The possibility of selecting one resonance among many for sensing application is also studied both theoretically and experimentally. A high sensitivity sensor based on WGM resonance in mm-wave and terahertz is proposed, and its sensitivity is studied in details. The performance of the proposed sensor is tested for sensing drug tablets and also liquid droplets through various measurements in mm-wave range. The comprehensive sensitivity analysis shows the ability of the proposed sensor to detect small changes in the order of 10−4 in the sample dielectric constant. The results of various experiments carried out on drug tablets are reported to demonstrate the potential multifunctional capabilities of the sensor in moisture sensing, counterfeit drug detection, and contamination screening. The measurement and simulation results obtained in mm-wave hold promise for WGM to be used for sensing biological solutions in terahertz range with very high sensitivity.
266

A Study on the Change of Chinese Oil Painting in Art Market

Yeh, Wei-lih 10 September 2009 (has links)
The purposes of this thesis are probing into the change of Chinese Oil Painting in art market. By means of this study, we will able to understand the development processes of the art markets in China, on the other hand, to gather the data from the auction market of different age artists and analysis them. Furthermore, it¡¦s the way to clarify how strong the art market in China is, or just the strategy to sensationalize the whole market to get high attention. But, it¡¦s obvious to find out that the environment affects the artists¡¦ creation a lot, but the works in the art market will go by chance. Therefore, to conclude that the Chinese art market is immature because the position of Chinese oil paintings is not fixed by Chinese government, Chinese artists and Chinese art market, but the art market in the world. Consequently, the Chinese art market needs to connect with the international art market.
267

Konsthallar och gallerier på nätet : En retorisk analys om konsten att övertyga om (samtids)konst / Art galleries on the Internet : A rhetorical analysis about the art to convince about (contemporary) art

Lindholm, Viktoria January 2008 (has links)
<p>Uppsatsen undersöker retoriken runt konst på fyra konstverksamheters hemsidor. Konsthallarna och gallerierna som undersöks är alla belägna på landsbygden eller i mindre samhällen i Sverige. Dessa är Bjurbäcks konsthall, Virserums konsthall, Neon Gallery samt Galleri Astley. De frågor som ställs till materialet är: Vilken konst är det som presenteras och hur lyfts den fram? Vilka retoriska medel använder man sig av, och vem vänder man sig till? I vilka sammanhang presenteras konst? Vilken relation och vilket synsätt till konst förmedlas? Vilken relation till platsen och miljön där konsthallen och galleriet är belägen förmedlas?</p><p>För att undersöka hur konstverksamheternas retorik är upplagd på hemsidorna har framförallt de klassiska begreppen ethos, logos och pathos fungerat som analysverktyg så som de används i metoden retorikanalys. Retorikanalys menar Brigitte Mral är en användbar metod som kan hjälpa oss att försöka förstå och tolka budskap. Hur bilder och design på olika sätt samspelar med texten har också varit viktigt att undersöka. Den redovisade analystexten i uppsatsen visar på samband mellan bild- och textretorik och hur dessa tillsammans bildar en gemensam retorik.</p><p>Teorier som används i uppsatsen ger perspektiv på begreppet konst. Förutom filosofiska definitionsförsök av vad konst är eller kan vara, presenteras här föreställningar om konst i relation till tre områden: företag, teknologi och media.</p><p>Ytterligare en teoretisk ingång som tolkats som relevant i uppsatsen, är att se på den lokala platsen i relation till nationen, EU och den globala världen.</p><p>Resultatet i uppsatsen visar att de fyra konstverksamheterna valt olika sätt att marknadsföra konst på sina respektive hemsidor, men trots detta är retoriken för samtidskonst ofta ganska traditionell. Hemsidan kan uppfattas som en kombinerad informations- och marknadsföringskanal. Den måste kunna fungera för olika målgrupper, såsom samarbetspartners, finansiärer, skolor, med mera. Detta är något som problematiseras i uppsatsen.</p> / <p>The essay examines the rhetoric around art on four art galleries´ homepages. The art galleries that are examined are all located on the countryside or in smaller towns in Sweden. With their Swedish names the examined objects are the following: Bjurbäcks konsthall, Virserums konsthall, Neon Gallery and Galleri Astley. The questions that are set to the material are: What kind of art is presented and how is it conveyed? Which rhetorical instruments are used and which target groups do they aim at? In which context is art presented? Which relation to art and which perspective on art is mediated? Which relation to the site and the environment where the art galleries are located is conveyed?</p><p>The classical concepts ethos, logos and pathos - as they are used in Rhetorical analysis - have been used as instruments to investigate how the rhetoric about art is applied. Brigitte Mral means that Rhetorical analysis is a useful method to help us understand and interpret messages. How pictures and design in different ways interplay with the text, has also been important to investigate. The presented analysis in the essay shows the connections between text- and visual rhetoric, and how these elements together form a common rhetoric.</p><p>Theories that are used in the essay give perspectives on the concept of art. Definitions about what art can be are presented mainly from a philosophical perspective. But the idea of art is also presented in relation to three other spheres such as companies, technology and the media.</p><p>Another theoretical input interpreted as relevant in the essay, is the perspective on the local place in relation to the nation, EU and the global world.</p><p>The result in the essay shows that the four art galleries have chosen different ways to market art on their respective homepages. Despite this is the rhetoric on contemporary art mainly traditional. The homepage can be considered as a combined information- and marketing channel. It must function for different target groups such as collaborative partners, financiers, schools, etc. This is examined and discussed in the essay.</p>
268

Looking forward together : three studies of artistic practice in the South, 1920-1940 / Three studies of artistic practice in the South, 1920-1940

Lindenberger, Laura Augusta 29 January 2013 (has links)
In this dissertation, I provide three studies of artistic practice in the era of the Great Depression. In each chapter, I write about a different set of artists working in the southeastern United States: I write about Walker Evans and the artistic and literary community located in the French Quarter of New Orleans, Louisiana (1926-1941); Edwin and Elise Harleston and their portrait studio in Charleston, South Carolina (1922-1931); and Bill Traylor and the artists who founded the New South Gallery and Art School in Montgomery, Alabama (1939-1940). Drawing from public and private archival collections, I consider how these artists made works that represented the South while they also made connections with artists and visual communities elsewhere; these connections placed them in dialogue with artists of the Harlem Renaissance, of American Regionalism, and of the Mexican Mural Movement. Although the artists in each chapter were from different Southern cities, they shared similar interests in the importance of developing and participating in artistic community. I situate each study in this dissertation in relation to a type of artistic practice. These types of artistic practice—documentary, portraiture, and exhibition—served as loci for Southern artists’ ideas about time and place. Southern studies have been haunted by the idea that the South always looks backward, to the past. In these three studies, I consider how Southern artists and their contemporaries in other places took different approaches to referencing the past and imagining a future for the South. The works made by these Southern artists—which are linked by their complicated relationships to race, history, and place—are largely absent from histories of American and 20th century art. Their absence tells us much about the stakes behind history writing. By bringing these studies into dialogue with other, existing, art historical contexts and communities, I trace how historical absence is constructed and why such absences are important to consider. The works in this dissertation are also linked by their difference from a kind of Modernism; in their multiple and discrepant modernisms, the artists in this dissertation made work which was both modern and not-modern, which looked backward while pushing forward. / text
269

Confronting nightmares : responding to iconoclasm in Western museums and art galleries

Scott, Helen E. January 2009 (has links)
It is not an everyday event for an artwork in a museum or gallery to be harmed deliberately by a member of the public. Such acts of iconoclasm do occur more regularly than many people might assume though, and when attacks take place the repercussions can be serious. This thesis examines the ways in which cultural institutions react to this phenomenon, investigating how responses could be improved to tackle it more effectively. The first chapter establishes the context to the discussion by categorising and rationalising the various motives behind iconoclastic crimes. The next chapter concentrates on historical trends of response, using the case of the suffragette iconoclasts to illuminate reactions from across society, before assessing the effects of their endurance. The third chapter broaches new ground in the field of prevention by exploring the access and education approach: a means of forestalling destructive compulsions among the public by promoting engagement with cultural institutions and works of art. The fourth chapter looks at security enhancement: the more traditional answer to iconoclastic offences. It evaluates the options open to museums from a defensive standpoint, but it also discusses the wider impact of implementation on accessibility. The final chapter presents the findings of a postal survey of 250 British museums and galleries undertaken in 2006. The purpose of the survey was to gauge the current nature and extent of the problem, and to determine how contemporary museum professionals deal with it. Although some cultural institutions respond to iconoclasm with considered, sustainable and effective tactics, others would be wise to revise their conduct. This thesis concludes that while instances of iconoclasm will never be eradicated from galleries completely, the threat could be curbed significantly if the museum sector was to make a concerted effort to study its own responses and introduce necessary changes.
270

ART AS RESEARCH: UNTANGLING THE ECOLOGICAL CITIZEN

FIGGE, LISA 08 September 2010 (has links)
In this thesis, Lisa Figge analyzes the political space of ecological citizenship by theorizing her art practice. Beginning with an Arendtian lens, Figge creates projects in the vein of New Genre Public Art, to trace the qualitatively-distinct activities of the public sphere, in which ecological citizens appear. The art practices of Mierle Laderman Ukeles, Colette Urban, Pat Aylesworth, Helen and Newton Harrison help move this critique along. Then, taking Judith Butler’s thinking on the bond between speech and action, or speech acts, Figge situates her art practice and thesis writing as an account of herself as an ecological citizen. Figge is interested in finding ways to multiply opportunities, for her and others, to perform concerned engagement with the world. In order to begin this process Figge acts out and analyses her three art interventions: Madame E and her suit of environmentally conscious a(r)mour, Ecological Citizen in Training, and 86 Hands on Wolfe Island. In giving an account of herself, she shows how our aptitude for sorting things should not be used to override our capacity to make a meaningful life. The art exhibition Dust to Dust, 2010 is the twin of this accounting, which was held at Queen’s University’s Union Gallery. / Thesis (Master, Environmental Studies) -- Queen's University, 2010-09-06 18:48:33.277

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