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Dissertations / Theses on the topic 'Light stage'
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Bajt, David. "Real-time Simulation of Volumetric Stage Light." Thesis, Linköpings universitet, Institutionen för teknik och naturvetenskap, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-95357.
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As current pre-visualization applications for the stage lighting industry only is developed for the PC-market, this master thesis can be considered as the first graphics engine prototype implementation of a completely new visualizer, not only for Mac, but for all platforms. The result is a cross-platform application in real-time, fully concentrated in simulating a real stage spotlight which not only illuminates surfaces, but also the air itself, referred to as volumetric light. In order to achieve such a phenomenon, a texture-based approach is used, mainly implemented in a fragment shader and therefore takes full advantage of the powerful Graphics Processing Unit (GPU). Similar to traditional ray tracing based algorithms, the method calculates light intensity on a per-pixel basis by integrating scattered light along the ray. The algorithm can also render surface shadows, shadow holes and create gobo effects in the volumetric lighting using a shadow mapping method. As the quality of light, shadows and surface characteristics are one of the most competitive features in a modern visualizer, these attributes are of greatest concern. I n order to alter light source parameters such as light intensity, color, zoom, etc. during run-time, a simple graphical user interface (GUI) is also attached to the application. I n brief, this master thesis stands as the “proof of concept”, i.e. a study if the latest real-time graphics technology, including OpenGL- and shader programming, often used in Windows environments also can be used for volumetric stage light simulations in a Macintosh environment.
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Salyer, Jeffrey William. "The expressionist stage in light of Bataillian expenditure /." Thesis, Connect to this title online; UW restricted, 1999. http://hdl.handle.net/1773/6678.
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Hudson, Andrew Ian. "Output limitations to single stage and cascaded 2-2.5μm light emitting diodes." Thesis, University of Iowa, 2014. https://ir.uiowa.edu/etd/1468.
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Since the advent of precise semiconductor engineering techniques in the 1960s, considerable effort has been devoted both in academia and private industry to the fabrication and testing of complex structures. In addition to other techniques, molecular beam epitaxy (MBE) has made it possible to create devices with single mono-layer accuracy. This facilitates the design of precise band structures and the selection of specific spectroscopic properties for light source materials.
The applications of such engineered structures have made solid state devices common commercial quantities. These applications include solid state lasers, light emitting diodes and light sensors. Band gap engineering has been used to design emitters for many wavelength bands, including the short wavelength (SWIR) infrared region which ranges from 1.5 to 2.5 μm [1]. Practical devices include sensors operating in the 2-2.5 μm range. When designing such a device, necessary concerns include the required bias voltage, operating current, input impedance and especially for emitters, the wall-plug efficiency. Three types of engineered structures are considered in this thesis. These include GaInAsSb quaternary alloy bulk active regions, GaInAsSb multiple quantum well devices (MQW) and GaInAsSb cascaded light emitting diodes.
The three structures are evaluated according to specific standards applied to emitters of infrared light. The spectral profiles are obtained with photo or electro-luminescence, for the purpose of locating the peak emission wavelength. The peak wavelength for these specimens is in the 2.2-2.5μm window. The emission efficiency is determined by employing three empirical techniques: current/voltage (IV), radiance/current (LI), and carrier lifetime measurements. The first verifies that the structure has the correct electrical properties, by measuring among other parameters the activation voltage. The second is used to determine the energy efficiency of the device, including the wall-plug and quantum efficiencies. The last provides estimates of the relative magnitude of the Shockley Read Hall, radiative and Auger coefficients. These constants illustrate the overall radiative efficiency of the material, by noting comparisons between radiative and non-radiative recombination rates.
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Waterman, Glennis. "LX: A Life in Light." ScholarWorks@UNO, 2019. https://scholarworks.uno.edu/td/2655.
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The author looks back over a long career working as a stage lighting technician in the American theatre, sharing personal experiences, and providing an insider’s view of the art, history, and culture of theatrical lighting.
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Shahlaei, Davoud [Verfasser]. "Single-image inverse lighting of faces with a virtual light stage / Davoud Shahlaei." Siegen : Universitätsbibliothek der Universität Siegen, 2018. http://d-nb.info/1161942971/34.
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Bradford, Levi. "Lighting the Stage: The Lighting Design Process and Production of Will Eno's Middletown." Digital Commons @ East Tennessee State University, 2020. https://dc.etsu.edu/honors/604.
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The world of theatre focuses on presentation and showmanship, but what audience never sees is often the most vital parts of the show. Behind the curtains, in the backstage of the theatre is where the real magic happens. This paper focuses on shedding some light on one aspect of the backstage. Without light, nothing would be seen. Follow along as the process of being chosen, creating, research, and production are revealed and explained to make the backstage more appreciated.
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Savelli, Ilaria. "Rhythms of anorexigenic neuropeptides in senegalese sole: Effects of light, feeding regimes and developmental stage." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/8405/.
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Increasing knowledge on the endocrine mechanisms that regulate feeding and growth in cultured fish can contribute to make improvement in fish holding conditions and feeding strategies, supporting the development of new techniques that could ameliorate feeding, food conversion efficiency and growth in aquaculture practice.
The main objective of this study was to investigate how daily mRNA expression of three specific anorexigenic hormones, i.e. the corticotropin-releasing hormone (CRH) and the paralogues α- and β- proopiomelanocortin (POMC), is modulated by different photoperiods, light spectra and feeding regimes, in both adult and larvae of Solea senegalensis. In addition, as Senegalese sole exhibits a shift from diurnal to nocturnal in locomotor activity and feeding habits during metamorphic process, we tried to elucidate if this shift is accompanied by relevant daily variations in the expression of these anorexigenic hormones before, during and after the completion of metamorphosis. In order to reach this main objective, three main experiments were developed. In a first experiment, adults were reared under LD (12 h light: 12h dark) cycle and fed at mid-light (ML), mid-dark (MD) and at random (RND). In a second experiment, adult specimens were reared in constant darkness (DD) and fed at subjective mid-light (sML) or at RND. Larvae of Senegalese sole were reared under LD cycle with white, blue or red light for 40 days. Our results show an independence of crh mRNA expression from the feeding time and suggest an endogenous control of crh expression in sole. Both pomc paralogues showed significant daily rhythms under LD conditions. The rhythms were maintained or were even more robust under DD conditions for pomc_a, but were completely abolished for pomc_b. Our results indicate an endogenous control of pomc_a expression by the molecular clock in telencephalon and diencephalon, but not in the pituitary gland. Our findings confirm for the first time the significant influence that ambient lighting has on larval growth and development in Senegalese sole, revealing an important effect of light spectra upon functional elements of this species. Our results also emphasize the importance of maintaining cycling light-dark conditions of the adequate wavelengths in aquaculture practices during early development of sole.
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Lishner, Benjamin C. "A scenic design for Adam Rapp's Red Light Winter| Creating two universes on a small stage." Thesis, California State University, Long Beach, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1591633.
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Adam Rapp's Red Light Winter, produced by the University Players at California State University, Long Beach is a play that explores the difference between memory, nostalgia, and reality. The creation of an effective scenic design involves zeroing in on the central meaning of the piece and formulating through metaphoric and poetic associations a stage design that effectively communicates these associations and meanings to the audience. Red Light Winter is ultimately about how people struggle to reconcile their memories, the reality of the present, and strong feelings of nostalgia and how these three things can become intertwined, sometimes to disastrous effect. This visual and poetic association allows for the creation of a room space on stage that forces the audience to look metaphorically through the walls of the room into a confined and claustrophobic memory space. The creation of this room by definition also creates a space outside this room. Just as the audience is peering through the walls of the room and into the memories of the characters, all three characters at some point must see beyond their own memories and catch a glimpse of the harsh reality - the "outside" - of their lives.
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Kylner, Carina. "Light scattering for analysis of thermal stress induced deformation in thin metal films." Doctoral thesis, KTH, Fysik, 1997. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-2547.
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Today, thin film based devices are found in a wide field of applications. The main reasons are that thin film technology enables access to unique physical properties and possibilities to miniaturize devices. Thin film devices are generally described in terms such as electrical, optical and magnetical properties. However, the lifetime of these devices is often limited by mechanical stresses causing plastic deformation. An effect of the plastic deformation is hillocking where isolated features are created on the film surface. The continual need to improve performance, reduce size as well as cost is pushing thin film structures close to or beyond present fundamental understanding. Further progress requires better understanding of basic phenomena where analytical methods for characterization of thin film deformation play a crucial role. To follow the initial hillock formation during thermal treatments it is essential to have a suitable tool for achieving real-time measurements with high sensitivity over a relatively large area that does not considerably affect the film surface. Methods based on light scattering are generally very sensitive to changes in the surface topography and allow contact free measurements at high speed. In this thesis light scattering methods are investigated as tools for stress analysis of thin metal films. Detection and characterization of isolated surface features using angular resolved scattering has been investigated by simulations. Results were used in development of an optical instrument for simultaneous measurements of initial hillocking and changes in overall film stress. The instrument combines light scattering and laser beam deflection techniques. It is shown how the onset of initial hillocking in aluminum films is accompanied by stress relaxation. Real-time dark field microscopy was demonstrated as a technique for analysis of the lateral hillock distribution. Analysis of the distribution show clustering of hillocks which is supposed to be related to the microstructure of the film. It is demonstrated that copper inclusion can be used to strengthen aluminum films to withstand higher stress before hillocking occurs. The copper content also reduces the grain size and thereby the surface roughness, which results in good or even better optical performance than for pure aluminum films.NR 20140805
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Nourgaliev, Robert R. "Modeling and analysis of heat and mass transfer processes during in-vessel melt progression stage of light water reactor (LWR) severe accidents /." Stockholm : Tekniska högsk, 1998. http://www.lib.kth.se/abs98/nour0427.pdf.
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Nuttall, Daniel Robert. "Advanced high frequency switched-mode power supply techniques and applications." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/advanced-high-frequency-switchedmode-power-supply-techniques-and-applications(5792cb86-58e3-488b-b27e-559c18e55250).html.
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This Thesis examines the operation and dynamic performance of a single-stage, single-switch power factor corrector, S4 PFC, with an integrated magnetic device, IM. Also detailed isthe development and analysis of a high power light emitting diode, HP LED, power factorcorrection converter and proposed voltage regulation band control approach.The S4 PFC consists of a cascaded discontinuous current mode, DCM, boost stage anda continuous current mode, CCM, forward converter. The S4 PFC achieves a high powerfactor, low input current harmonics and a regulated voltage output, utilising a singleMOSFET. A steady-state analysis of the S4 PFC with the IM is performed, identifying theoperating boundary conditions for the DCM power factor correction stage and the CCMoutput voltage regulation stage. Integrated magnetic analysis focuses on understanding theperformance, operation and generated flux paths within the IM core, ensuring the device doesnot affect the normal operation of the converter power stage. A design method for the S4 PFCwith IM component is developed along with a cost analysis of this approach. Analysis predictsthe performance of the S4 PFC and the IM, and the theoretical work is validated by MATLABand SABER simulations and measurements of a 180 W prototype converter.It is not only the development of new topological approaches that drives theadvancement of power electronic techniques. The recent emergence of HP LEDs has led to aflurry of new application areas for these devices. A DCM buck-boost converter performs thepower factor correction and energy storage, and a cascaded boundary conduction current modebuck converter regulates the current through the LED arrays. To match the useful operatinglifetime of the HP LEDs, electrolytic capacitors are not used in the PFC converter. Analysisexamines the operation and dynamic characteristics of a PFC converter with low capacitiveenergy storage capacity and its implications on the control method. A modified regulationband control approach is proposed to ensure a high power factor, low input current harmonicsand output voltage regulation of the PFC stage. Small signal analysis describes the dynamicperformance of the PFC converter, Circle Criterion is used to determine the loop stability.Theoretical work is validated by SABER and MATLAB simulations and measurements of a180 W prototype street luminaire.
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Ochoa, Manoel João. "Campos de luz: contaminações luminosas no Teatro Paulistano 2011-2012." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/27/27156/tde-21092015-155451/.
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Este trabalho pesquisa as aplicações da iluminação cênica em alguns coletivos teatrais paulistanos no período de 2011-2012, para entender a prática do desenho da luz, constatando a utilização ou não de novos equipamentos e técnicas. Para isso, fez-se o estudo de peças produzidas e apresentadas no período mencionado, e entrevistas com iluminadores, diretores e outros profissionais da cena ligados a grupos filiados à Cooperativa Paulista de Teatro e contemplados com o Programa de Fomento ao Teatro da Cidade de São Paulo. Outra preocupação deste trabalho foi a análise da formação dos profissionais de iluminação desses coletivos.This work researches the aplication of Lighting designer in Drama groups from São Paulo between 2011 and 2012, for understand the pratice of light shape and the using of modern equipments and technics. Therefore, a study was made about plays produced and presented in the mentioned period, and interviews with lighting designers, directors and other professionals in the area related of groups affiliate with the São Paulo Drama Company e benefit from the Program of Promotion of the Theater in the city of São Paulo. Another of this work was a analysis of the formation of the Light Designers of this groups.
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Germishuys, Jurie J. "Free light chains in patients with HIV: establishing local reference ranges and their association with stage of disease, chronic antigen stimulation and the effect of Haart." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/20173.
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Thesis (MMedSc)--Stellenbosch University, 2012.ENGLISH ABSTRACT: Background: Serum free light chains (FLC) are associated with imbalances in heavy and light chain production. Abnormal FLC ratios have been associated with risk of progression in certain diseases. Automated assays are available for their determination and they are used in the followup and management of patients with monoclonal gammopathies. Acceptable imprecision, specificity, accuracy and reproducibility between reagent batches is required to prevent under- or overestimation. Method validation is a standard process in every good laboratory to judge the acceptability of a new method. Reference intervals have been established in an older population, but it was considered important to verify these in our population. HIV is associated with B-cell dysfunction. As B-cell abnormalities are associated with disorders leading to monoclonal gammopathies, we postulated that the FLC levels and FLC ratio would be abnormal in HIV infected individuals. Methods and materials: Controls and pooled patient samples were used for the method validation study which included imprecision studies, linearity, recovery and interference studies, and method comparison studies, the latter compared our method to the same method used in another laboratory. For the reference interval study, blood was obtained from 120 healthy subjects. The following blood tests were performed: total protein, IgG, IgA, IgM, creatinine, protein electrophoresis, kappa FLC and lambda FLC. Using the kappa and lambda FLC results, a FLC ratio was determined. Three hundred and sixty-nine HIV positive subjects were then studied. The same tests were performed, as well as CD4+ counts and viral loads on the majority of them. Results: For the method validation study, precision, linearity and recovery was acceptable. Minimal interference was observed with haemolysis, lipaemia, bilirubin and rheumatoid factor. Our method showed comparable performance with the established method. For the reference interval study, all the creatinine values were normal, as were serum protein values. The serum protein electrophoreses were independently reviewed by 3 pathologists. Most were normal, with a few polyclonal increases seen, but no definite monoclonal bands. The 95% reference intervals for FLC’s as well as the FLC ratio were not statistically significantly different to the manufacturer’s recommendations. When examining the HIV positive study population, we found that FLC and FLC ratio were influenced by markers of HIV disease severity, such as CD4+ count, IgG, viral load, use of antiretroviral treatment and abnormal serum protein electrophoreses. Conclusion: The validation study of FLC showed excellent precision, acceptable bias, good linearity, good recovery and minimal interference, allowing routine introduction of the test. The 95% reference intervals obtained for our population were slightly higher than those recommended by the manufacturer. However, as most of the values fell within the manufacturer’s limits, we could accept the manufacturer’s recommended cut-offs. We found that FLC levels were definitely influenced by markers of HIV disease severity in our population and we postulate that they may be of use for follow-up of patients with HIV.
AFRIKAANSE OPSOMMING: Agtergrond: Serum vry ligte kettings (VLK) word geassosieer met ‘n wanbalans van ligte en swaar ketting produksie. Abnormale VLK ratios is geassosieer met ‘n risiko van verloop in sekere siektes. Geoutomatiseerde laboratorium toetse vir VLK is beskikbaar vir hul bepaling en word gebruik om pasiënte met monoklonale gammopatieë op te volg en te behandel. Aanvaarbare impresisie, spesifisiteit, akkuraatheid en herhaalbaarheid tussen reagens besendings is belangrik om onder- of oorbepaling te verhoed. Metode validasie is ’n standaard proses in elke goeie laboratorium om die aanvaarbaarheid van ’n nuwe metode te bepaal. Verwysingswaardes is al bepaal in ’n ouer populasie. Ons het besluit om die verwysingswaardes in ons populasie te bepaal. Mens-immuungebrekvirus (MIV) word geassosieer met B-sel disfunksie. Omdat B-sel abnormaliteite geassosieer word met afwykings wat tot monoklonale gammopatieë lei, het ons gepostuleer dat die VLK vlakke en VLK ratio abnormaal sal wees in MIV geïnfekteerde persone. Metodes en Materiale: Kontroles en pasiënt monsters is gebruik vir die metode validasie studie wat impresisie studies, lineariteit, herwinning, inmenging en metode korrelasie studies ingesluit het. In laasgenoemde geval is ons metode met dieselfde metode van ’n ander laboratorium vergelyk. Vir die verwysingswaardes studie is 120 gesonde persone se bloed gebruik. Die volgende toetse is bepaal: totale proteïen, IgG, IgA, IgM, kreatinien, proteïen elektroferese, kappa en lambda VLK. Die VLK ratio is bepaal deur die kappa en lambda resultate te gebruik. Driehonderd nege en sestig MIV-positiewe pasiente is gebruik vir die studie. Dieselfde toetse was gedoen, asook CD4+ tellings en virale ladings op die meerderheid van pasiente. Resultate: Vir die metode validasie studie, was presisie, lineariteit en herwinning aanvaarbaar. Minimale inmenging van hemolise, lipemie, bilirubien en rumatoïede factor is waargeneem. Ons metode het goed gekorreleer met die bepaalde metode. Die serum kreatinien en serum totale proteïen waardes was normaal tydens die verwysingswaardes studie. Die serum proteïen elektroferese was onafhanklik beoordeel deur 3 patoloë. Die meeste was normaal met enkele poliklonale verhogings, maar geen definitiewe monoklonale bande nie. Die 95% verwysings intervalle vir VLK en VLK ratio het nie statisties betekenisvol verskil van die vervaardiger se aanbevelings nie. In die studie van die MIV-positiewe studie populasie, het ons gevind dat VLK en VLK ratio beïnvloed word deur merkers van ernstige MIV siekte, soos CD4+ telling, IgG, virale lading, die gebruik van antiretrovale medikasie en abnormale serum proteïen elektroferese. Gevolgtrekking: Die validasie studie van VLK het uitstekende presisie, aanvaarbare partydigheid, goeie lineariteit, goeie herwinning en minimale inmenging gewys, wat die roetine instelling van die toets toegelaat het. Die 95% verwysingsintervalle wat vir ons populasie bepaal is, was effens hoër as die vervaardiger se aanbeveling. Die meeste van die waardes het egter binne die vervaardiger se limiete geval, dus kon ons die vervaardiger se afsnypunte aanvaar. Ons het gevind dat VLK vlakke definitief beïnvloed word deur merkers van die ernstigheidsgraad van MIV siekte in ons populasie en ons postuleer dat VLK van waarde kan wees met die opvolg van MIV pasiente.
NHLS
Harry Crossley for funding obtained
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Kalyagina, Nina. "Diffuse Reflectance Endoscopic Imaging for Bladder Early-Stage Cancer and Pre-Cancer Diagnosis : Instrumentation, Modelling and Experimental Validation." Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0099/document.
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L'objectif de cette thèse est d'évaluer les performances d'une méthode d'imagerie optique non-invasive pour la détection de précancers et cancers précoces de la vessie, à l'aide d'une analyse de lumière laser rétro-diffusée. L'analyse de la distribution spatiale de la lumière à la surface de fantômes multi-couches imitant l'épithelium de vessie avec différentes propriétés d'absorption et de diffusion nous a permis de montrer les modifications de ces propriétés optiques entraînent des changements de la taille de la surface du spot de lumière rétro-diffusée, mesurables par une caméra vidéo. La méthode développée est également sensible à l'accumulation d'un photosensibilisateur et est applicable aussi bien pour des études en réflectance diffuse qu'en fluorescence induite. Les paramètres optiques des fantômes synthétiques tri-couches imitant différents états des épithéliums de vessie ont été calculés à partir de la théorie des ondes électromagnétiques appliquée aux diffuseurs sphériques sans et avec une couche. Ces paramètres ont servi comme entrées aux simulations de Monte Carlo qui ont permis d'obtenir les matrices des distributions d'intensité de réflectance diffuse. Notre étude démontre que les mesures en imagerie de réflectance diffuse non-polarisée permettent de fournir des informations utiles au diagnostic tissulaireThe present thesis aimed to evaluate the performance of non-invasive optical method for bladder pre- and early- cancer detection by means of diffuse-reflected laser light analysis. The analysis of light distribution at the surface of multi-layered bladder phantoms with different scattering and absorption properties showed that the changes in the optical properties lead to increase or decrease of the diffuse-reflected light spot area, detectable by a video camera. It was also determined, that the presented method is capable of detection of the photosensitizer accumulation, and can be applied for both (diffuse-reflected laser and fluorescence) studies simultaneously. The calculations for spherical and ?coated?-spherical tissue scatterers, based on the electromagnetic wave theory, allowed for obtaining optical parameters of three-layered biological phantoms and of bladder tissues at different states. These parameters served as inputs for Monte Carlo simulations, which provided us with matrices of diffuse-reflected light distributions. The study showed that the measurements of non-polarized back-scattered laser light can provide useful information on the tissue state
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Johansson, Erik. "3D Reconstruction of Human Faces from Reflectance Fields." Thesis, Linköping University, Department of Electrical Engineering, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2365.
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Human viewers are extremely sensitive to the appearanceof peoples faces, which makes the rendering of realistic human faces a challenging problem. Techniques for doing this have continuously been invented and evolved since more than thirty years.
This thesis makes use of recent methods within the area of image based rendering, namely the acquisition of reflectance fields from human faces. The reflectance fields are used to synthesize and realistically render models of human faces.
A shape from shading technique, assuming that human skin adheres to the Phong model, has been used to estimate surface normals. Belief propagation in graphs has then been used to enforce integrability before reconstructing the surfaces. Finally, the additivity of light has been used to realistically render the models.
The resulting models closely resemble the subjects from which they were created, and can realistically be rendered from novel directions in any illumination environment.
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van, Dijk Jeroen. "Size and Abundance of Late Pleistocene Reticulofenestrid Coccoliths from the Eastern Indian Ocean in Relation to Temperature and Aridity." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-325273.
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Measurements on coccolith abundance and mass can be used as a signal of primary productivity and pelagic calcification in response to environmental change. The Leeuwin Current (LC) is known to transport warm and low-salinity waters from the Indo-Pacific Warm Pool (IPWP) southwards along the coast of West Australia. Along with the onset of continental aridity during late Neogene, increased strength of the LC may have played a role in reef expansion on the Northwest Shelf. In this study the morphological variation in size and mass of reticulofenestrid coccoliths was assessed in material from IODP Site U1461 in the eastern Indian Ocean spanning the past 500 ka. Both the absolute abundance of all reticulofenstrid coccoliths (Emiliania huxleyi, Reticulofenestra spp., Gephyrocapsa spp. and Pseudoemiliania spp.) was determined, as well as the relative abundance of large versus small coccoliths. Coccolith size and mass were measured quantitatively under circularly polarized light. The data was compared to variations in sea surface temperatures (SST) of the LC, and to continental aridity of Australia. SST fluctuations could influence coccolithophore productivity by affecting their metabolic rate, whereas continental aridity may influence the influx of terrestrial matter by wind. The investigated interval is dominated by small species of Gephyrocapsa. Peak values of absolute abundance and mass were observed during Marine Isotope Stage (MIS) 11, an interglacial period of extended warmth and humidity. These results coupled with high densities of aragonite needles in the same samples indicate the sediments were diluted by material overflowing from the adjacent shallow- water carbonate platform, analogous to the whiting events observed in the modern-day Bahamas. A decrease in abundance of Gephyrocapsa caribbeanica at 240 ka can be linked to the timing of their last common occurrence (LCO), within MIS 7. The subsequent shift to Gephyrocapsa oceanica as the dominant large species may indicate an ecological replacement of G. caribbeanica, or signify warm and low-salinity waters.Mätningar av abundans och massa hos coccoliter kan användas som en signal för primärproduktion och pelagisk förkalkning som resultat av miljöförändringar. Leeuwin Current (LC) är känd för att transportera varmt vatten och vatten med låg salthalt från Indo-Pacific Warm Pool (IPWP) söderut längs kusten i västra Australien. Tillsammans med början av kontinental torka under sen Neogen kan ökad styrka hos LC ha spelat en roll i expansionen av rev på nordvästsockeln. I denna studie bedömdes den morfologiska variationen i storlek och massa hos coccoliter i material från IODP plats U1461 i östra Indiska oceanen från de senaste 500 000 åren. Både den absoluta abundansen av alla reticulofenstridcoccoliter (Emiliania huxleyi, Reticulofenestra spp., Gephyrocapsa spp. och Pseudoemiliania spp.) bestämdes, liksom den relativa abundansen av stora jämfört med små coccoliter. Storlek och massa av coccoliter mättes kvantitativt under cirkulärt polariserat ljus. Uppgifterna jämfördes med variationer i havsytans temperatur (SST) hos LC, och med kontinental torrhet i Australien. SST-fluktuationer kan påverka produktiviteten hos coccolitoforider genom att påverka deras metabolism, medan kontinental torrhet kan påverka inflödet av markmaterial med vind. Det undersökta intervallet domineras av små arter av Gephyrocapsa. Toppvärden av absolut abundans och massa observerades under marinisotopsteget (MIS) 11, en interglacial period med förlängd värme och fuktighet. Dessa resultat kombinerat med hög densitet av aragonitnålar i samma prover indikerar att sedimenten späddes ut med material som svämmade över från den intilliggande grunda karbonatplattformen, vilket är jämförligt med de vitningshändelser som har observerats i dagens Bahamas. En minskning i abundans av Gephyrocapsa caribbeanica vid 240 ka kan kopplas till tidpunkten för deras senaste gemensamma förekomst (LCO) inom MIS 7. Den efterföljande övergången till Gephyrocapsa oceanica som den dominerande stora arten kan indikera en ekologisk ersättning av G. caribbeanica, eller indikera varmt vatten med låg salthalt.
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Moura, Luiz Renato Gomes. "A ilumina??o c?nica no trabalho do ator de teatro." Universidade Federal do Rio Grande do Norte, 2014. http://repositorio.ufrn.br:8080/jspui/handle/123456789/12465.
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This research aims to investigate how the stage lighting can be articulated in the creation of theater actor process. To we reach this reflection, it is necessary to understand the space of the rehearsal room, where the actor works as a place where their function receives influences of other artists who are creating the spectacle.Collaborative processes are analyzed three Cia de Teatro Engenharia C?nica: Irremedi?vel, 2007; Doralinas e Marias , 2009; O Menino Fot?grafo, 2011, aiming to understand the collaborative theater potentializes, the intersection and the exchange of experiences in the rehearsal room, collaborating actively for the training of persons involved in creating the show. The research proposes an investigation of how the creative process of stage lighting is gaining ground in the rehearsal room in the language of theater directing, showing mainly how is your "co-evolutionary" creation with the creative process of the actor
A presente pesquisa tem como foco principal, investigar como a ilumina??o c?nica pode ser articulada no processo de cria??o do ator de teatro. Para chegarmos a essa reflex?o, se faz necess?rio compreendermos o espa?o da sala de ensaio, no qual o ator trabalha, como um lugar em que sua forma??o, recebe influ?ncias dos demais artistas, que est?o tamb?m criando o espet?culo. S?o analisados tr?s processos colaborativos da Cia. de Teatro Engenharia C?nica: Irremedi?vel , Doralinas e Marias e O Menino Fot?grafo , com intuito de compreendermos que o teatro colaborativo potencializa o cruzamento e a troca de experi?ncias na sala de ensaio, colaborando ativamente para a forma??o dos sujeitos envolvidos na cria??o do espet?culo. A pesquisa prop?e uma investiga??o de como o processo criativo da ilumina??o c?nica ganhou espa?o na sala de ensaio na linguagem da encena??o teatral, evidenciando principalmente sua cria??o co-evolutiva com o processo criativo do ator
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Ward, Martin B. "Squeezed light in semiconductors." Thesis, University of Oxford, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270175.
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Nicol, David Brackin. "A Novel Solid State General Illumination Source." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/14032.
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A novel solid state illumination source has been developed. A two terminal dual LED has been created with the ability to control the relative intensities of the two emission peaks by varying drive current. Doping profiles have been used to extend the dynamic range of the dual LED over other reported devices. Operation of the dual LEDs is explained as a function of drive current. In addition, novel use of phosphor mixtures allows the creation of a broadband spectral power distribution that can be varied using a dual LED as an excitation source. Combinations of phosphors that have varied excitation spectra provide the ability to selectively excite different phosphors with the different LED emission peaks. First and second generations of the two terminal dual LED and the phosphor combination are discussed. The final source has the ability to mimic the light of a blackbody radiator over a range of 3200 K - 5300 K. The development of a three terminal dual LED as a pump source was prohibited by the need for a III-nitride tunnel junction, that proved unattainable in the scope of this work. However, several novel doping schemes were investigated toward this end. Finally, a circadian light source has also been developed that can affect physiological changes in humans, and a light box for entrainment of circadian rhythms in rats has been built.
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Philbrick, Robert H. "Modeling of light absorption in solid state imagers /." Online version of thesis, 1990. http://hdl.handle.net/1850/10557.
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Woodhead, Christopher Stephen. "Enhancing the light output of solid state emitters." Thesis, Lancaster University, 2017. http://eprints.lancs.ac.uk/88416/.
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The work in this thesis focuses on improving the light output of room temperature emitting materials, and nanostructures as a stepping stone for use as single photon sources. The primary nanostructures studied are III-V based type-II emitting quantum dots/quantum rings (QDs/QR’s), which emit at telecom wavelengths either in the O-band (GaSb/GaAs QRs) or the C-band (InAs/GaAs QDs capped with GaAsSb). Individual exciton emission at low temperature was observed in these samples using micro-photoluminescence for what we believe is the first time. This was achieved by reducing the excitation area of the sample using micropillars and gold aperture masks, combined with increasing the extraction efficiency of light using a solid immersion lens. The observation of individual exciton emission enabled their contribution to the power dependent blueshift of type-II quantum dots to be studied. The integration of the InAs/GaAs QDs with silicon was explored by studying their emission when they are grown on both GaAs and silicon substrates. Studies such as this are an important step towards integrating QDs with on-chip communications. Finally, solid immersion lenses formed from a UV-curable epoxy are explored as a method for increasing light out of 2D materials. It was found that for Tungsten Diselenide (WSe2) the solid immersion lens increased the intensity of the emitted photoluminescence, as well as preventing the monolayer from degrading. This method could prove to be an excellent method for increasing the light output of 2D material based LED’s, especially WSe2 based single photon sources.
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Sharpe, Donal J. "Laser light scattering from liquid surfaces." Thesis, Queen's University Belfast, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282336.
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Sefton, M. S. "Dynamic light scattering from thermotropic liquid crystals." Thesis, University of Manchester, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370981.
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Spence, C. A. "Light-induced effects in amorphous chalcogenide films." Thesis, University of Cambridge, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383912.
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Hsu, Chi-Yeh. "State Space Model of a Light Weight Flexible Telescope." DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/383.
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The accuracy of optical telescope in the past was dominated by the construction of the telescope body and the precision of optical surface. This thesis fits into a larger project with a goal of controlling a flexible telescope in order to help a cheaper telescope achieve higher accuracy. In order to understand the internal motion of telescope, the goal of this thesis is to build a state space model of a two-degree-of-freedom telescope using a known star location as feedback. The model presented in this thesis may be used for the telescope simulation and the control design in the future. This project considers a light weight flexible structured telescope and uses state space formulation to model dynamic motion of the telescope since state space model is better for modeling and analyzing a multiple-inputs and multiple-outputs system. A one-degree-freedom experimental test stand is built to generate a series of telescope motion data in order to examine whether the telescope simulation model can represent a real telescope system. To record the telescope motion, a wheel encoder mounted on the azimuth motor and a LED light density sensor installed at the end of telescope body are used as feedbacks. The results show that the state space model can simulate many system dynamic behaviors as shown in the experimental result; however, it is not feasible to obtain all of telescope’s physical parameters from the system feedbacks.
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Topple, Jessica. "Molecular thin films:characterization, control, and collection of light." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=107776.
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Deposition of submonolayer coverages of 3,4,9,10-perylenetetracarboxylic diimide (PTCDI) onto NaCl(001) results in the bimodal growth of coexisting square and needle-shaped islands. The epitaxy of each island type was determined from molecular and atomic resolution non-contact atomic force microscopy (NC-AFM) images. Post-deposition, the needle islands grow while the square islands disappear completely within days. This is characterized as a dewetting transition, the dynamics of which has been described and empirically fit to the monomolecular growth model, a model typically applied to biological growth.Methods of tailoring molecular thin film morphology and maturation rate were investigated. The island surface distribution, size, shape, and rate of dewetting of submonolayer coverages of PTCDI on alkali halides may be varied by changing growth conditions such as temperature and by templating the substrate with single atomic layer deep pits or depositing gold nanoclusters to modify island nucleation. This characterization is an important step in controlling the structure of thin organic films for devices that are sensitive to nanoscale film structure.Film morphology of organic photovoltaic materials can have a dramatic influence on device performance. Building upon previous morphological studies of tailoring molecular island size and nucleation site distribution, thin films of PTDCI (an electron donor) and copper (II) phthalocyanine (an electron acceptor) molecular islands were grown under ultra high vacuum conditions. Topography and surface contact potential were simultaneously mapped in a preliminary NC-AFM and Kelvin probe force microscopy study investigating structure-function relationships in photovoltaic energy generation.Le dépôt de sous-couche simples de 3,4,9,10-pérylénetetracarboxylic diimide (PTCDI) sur du NaCl (001) résulte en une croissance bimodale d'îles en formes d'aiguille et de carré. L'épitaxie de chaque type d'île a été déterminé par imagerie microscopique à force atomique non-contact (NC-AFM) avec des résolutions atomiques et moléculaires. Aprés le dépôt, les îles en forme d'aiguille croissent tandis que les îles de forme de carrés disparaissent complètement en quelques jours. Ceci est caractérisé par une transition de démouillage, pour laquelle la dynamique a été décrite et empiriquement ajusté au modèle de croissance mono-moléculaire, un modèle généralement appliqué aux croissances biologiques. Les méthodes d'adaptation de la morphologie des couches moléculaires minces et le taux de maturation ont été étudiés. La distribution de surface, la taille et la forme des îles, ainsi que le taux de démouillage des sous-couche simples de PTCDI sur les alkali-halides peuvent être modifiés en changeant les conditions de croissance telles que la température, en remodelant le substrat avec des trous profonds d'épaisseur atomique ou en déposant des nano-amas d'or pour modifier la nucléation des îles. Cette caractérisation est une étape importante pour le contrôler la structure des films organiques fins pour des appareils qui sont sensibles à la structure des films aux échelles nanoscopiques. La morphologie des films de matériaux organiques photovoltaïques peut avoir une influence importante sur la performance de ces appareils. En s'appuyant sur des études antérieures portant sur l'adaptation de la taille des îles moléculaires et la répartition des sites de nucléation, des films minces d'îles de PTDCI (un donneur d'électrons) et de cuivre (II) phthalocyanine (un accepteur d'électrons) ont été cultivés sous ultra haut vide. La topographie et le potentiel de contact à la surface ont été cartographié simultanément dans une étude préliminaire de microscopies NC-AFM et sonde Kelvin pour caractériser les relations entre la structure et la fonction de la génération d'énergie photovoltaïque.
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Kalaji, Ali. "Novel cerium-doped phosphors for solid-state lighting." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.607693.
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Henriksson, Johan. "Light Control using Organometallic Chromophores." Licentiate thesis, Linköping University, Linköping University, Computational Physics, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-17232.
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The interaction between light and organometallic chromophores has been investigated theoretically in a strive for fast optical filters. The main emphasis is on two-photon absorption and excited state absorption as illustrated in the Jablonski diagram. We stress the need for relativistic calculations and have developed methods to address this issue. Furthermore, we present how quantum chemical calculations can be combined with Maxwell's equations in order to simulate propagation of laser pulses through a materials doped with chromophores with high two-photon absorption cross sections. Finally, we also discuss how fast agile filters using spin-transition materials can be modeled in order to accomplish theoretical material design.
Report code: LIU-TEK-LIC-2006:55. On the day of the defence date the status on article III was Manuscript, article IV was Accepted and article V was Submitted.
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Mello, Olivia L. "Quantum state reconstruction and tomography using phase-sensitive light detection." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/92703.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Physics, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 69-70).
In this thesis we present an optical and electronic setup that is capable of performing coherent state tomography. We fully characterize it in order to verify whether or not it will be capable to perform non-demolition homodyne detection of squeezed light in a high-finesse cavity QED setup with an ensemble of Cesium atoms coupled to the cavity. After quantifying sources of noise, the photodiode efficiency, we perform a series of measurements of low photon number coherent states and compare them against the standard quantum limit. We discuss a variety of technical challenges encountered in such systems and some methods to overcome them. Lastly, we test the apparatus' ability to do quantum state tomography and quantum state reconstruction by reconstructing the density matrix and Wigner functions for low photon-number coherent states.
by Olivia L. Mello.
S.B.
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McGivern, Richard Canice. "Light scattering studies of thermal fluctuations of liquid surfaces." Thesis, Queen's University Belfast, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356895.
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Martin, Simon James. "Simulations of charge transport in organic light emitting diodes." Thesis, University of Bath, 2002. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250944.
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Parupudi, Arun Kumar. "Demonstration of scale-down dynamic light scattering and determination of osmotic second virial coefficients for proteins." Master's thesis, Mississippi State : Mississippi State University, 2007. http://sun.library.msstate.edu/ETD-db/theses/available/etd-11092007-112135/.
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Katelnikovas, Artūras. "Synthesis and characterization of luminescent materials for solid state light sources." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2012. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2012~D_20121227_090417-03709.
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The modern society relies heavily on mankind’s ability to produce light to lengthen the day. Throughout the evolution of artificial lighting lots of light sources were discovered / invented, i.e. burning wood, oil, candles, using incandescent bulbs and fluorescent lamps and, finally, white LEDs. LEDs are superior to other light sources due to their high efficiency. Replacement of conventional light sources by white LEDs what would allow saving huge amounts of electricity consumed for lighting purposes. The main goal of this dissertation was development and investigation of various new materials that could be used in solid state light sources based on near-UV and blue LEDs. One silicate, one molybdate and three garnet structure compounds were selected. Several synthesis methods, i.e. solid state, sol-gel, and sol-gel combustion, were applied in preparation of selected host materials. The host materials were activated by Eu2+, Eu3+, and Ce3+ ions. The phase purity of synthesized samples was evaluated by recording powder XRD patterns. Luminescent properties of the activator ions were investigated by recording reflectance, excitation, emission spectra and decay curves at room temperature. The temperature dependent decay curves and emission spectra were recorded in the range of 77-500 K. Moreover, quantum yields, luminous efficacies and colour points were calculated from the obtained data.Žmonija jau nuo senų senovės stengiasi prailginti dieną dirbtiniais šviesos šaltiniais. Šviesos šaltiniai vystėsi pamažu – iš pradžių buvo deginama mediena, žibalas ir žvakės, vėliau buvo išrasta kaitrinė lemputė, o dar po kurio laiko fluorescencinė lempa. Jauniausi iš dirbtinių šviesos šaltinių yra šviestukai, kurie yra pranašesni už prieš tai minėtus šaltinius savo dideliu efektyvumu. Pakeitus dabartinius šviesos šaltinius šviestukais, būtų galima sutaupyti milžinišką elektros energijos kiekį, suvartojamą apšvietimui. Pagrindinis disertacijos tikslas buvo buvo naujų liuminescencinių medžiagų, kurios gali būti sužadinamos ultravioletinę arba mėlyną spinduliuotę emituojančiais šviestukais, paieška. Iš viso pasirinktos penkios sistemos – vienas silikatas, vienas molibdatas ir trys granato struktūros junginiai. Medžiagos buvo susintetintos kietafazių reakcijų, zolių-gelių arba zolių-gelių užsiliepsnojimo metodais. Junginiai buvo legiruoti Eu2+, Eu3+ arba Ce3+ jonais. Fazinis junginių grynumas buvo patvirtintas Rentgeno spindulių difrakcijos analize. Junginių optinės savybės buvo įvertintos išmatavus atspindžio, sužadinimo ir emisijos spektrus bei liuminescencijos gesimo trukmes kambario temperatūroje. Taip pat buvo įvertinta junginių liuminescencijos gesimo trukmių ir emisijos spektrų priklausomybė nuo temperatūros, bei apskaičiuoti kvantiniai našumai ir spalviniai taškai.
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Dragan, Valer Carleton University Dissertation Physics. "Relativistic bound state equations for mesons in light-front momentum space." Ottawa, 1995.
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Barr, Matthew. "Alpha clustering in the ground state of neutron rich light nuclei." Thesis, University of Birmingham, 2014. http://etheses.bham.ac.uk//id/eprint/4884/.
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An experiment was conducted at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany, using the R³B experimental setup. This included an array of double sided silicon strip detectors and a 4π array of NaI scintillator detectors surrounding the target, a bending magnet and downstream fragment detectors consisting of scintillating fibre detectors and a plastic scintillator time of flight wall. Cross sections have been measured for the breakup of ^{7,9-12}Be and ^{8,10-15}B on proton and \(^↔\)C targets at beam energies between 260 and 540 MeV per nucleon. These cross sections have been analysed with a focus on comparison to cluster model theory. In the context of a large collaboration and an experiment with diverse physics objectives, it is worth clarifying the author's contribution to the work presented. The author participated in running the experiment, calibrated the Silicon Strip Detectors and performed all the analysis discussed in this thesis.
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Hayer, Anna. "Excited state formation, stabilisation and decay in polymer light-emitting diodes." Thesis, University of Cambridge, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.613996.
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Di, Fiori Nicolas. "Light-induced interactions of DNA, synthetic fluorophores and solid-state nanopores." Thesis, Boston University, 2013. https://hdl.handle.net/2144/12746.
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Thesis (Ph.D.)--Boston University
PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you.In the first part of my thesis I studied the effect of dye-dye interactions in labeled double-stranded DNA molecules on the Forster Resonance Energy Transfer (FRET) efficiency. FRET is a spectroscopic process by which energy is passed nonradiatively between molecules over long distances (10-100 A). The donor molecule, a fluorophore, transfers part of its energy to an acceptor, usually a second fluorophore, with an efficiency that depends strongly on their separation. I have found that when some fluorophores are covalently bounded to DNA, a second process which directly competes with FRET can be observed. I have studied these novel interactions by immobilizing the molecules on a surface and probing them one at a time, in this way avoiding ensemble averages that mask this phenomenon. By comparing four different donor-acceptor pairs I found that these interactions depend on the nature of the fluorophores. These results show for the first time that when dye-dye interactions are accounted for, single-molecule FRET can be used to accurately measure absolute inter-dye distances, even at the shortest separations. Secondly, these results are useful when deciding which dye pairs to use for nucleic acid analyses using FRET. In the second part, I found a novel effect between visible light and solid-state nanopores which allows us to slow down the speed at which nucleic acid threads through the pore (i.e. translocates). Solid-state nanopores are nanometer-sized holes drilled in thin ceramic films, and they hold the potential of achieving ultra-fast and cost-effective whole genome sequencing. A major deterrent to this goal is the lack of a way to modulate the translocation speed of nucleic acids without compromising the electrical signal. I have found that light enhances the pore conductance and simultaneously produces a >10-fold increase in the translocation time. I propose a mechanism to account for these observations that involve light-induced charges on the silicon nitride pore surface. With this assumption, I then successfully modeled the conductance enhancement created by light, and suggested an underlying physical mechanism that can explain the production of transient charges in silicon nitride membranes using visible light.
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Maillard, Patrick. "Influence de l'éthylène sur la croissance, la physiologie et le métabolisme d'haematococcus pluvialis." Compiègne, 1993. http://www.theses.fr/1993COMP0581.
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Toutes les souches de cyanobacteries (11 souches) et toutes les algues (56 souches dont 38 souches d'algues unicellulaires) peuvent produire de l'ethylene, dans nos conditions de culture. Chez haematococcus pluvialis, une variabilite intraspecifique existe pour la production d'ethylene et la synthese d'astaxanthine. La voie de biosynthese de l'ethylene chez haematococcus pluvialis est identique a celle des vegetaux superieurs. L'emission d'ethylene est fonction du flux lumineux et de la qualite de la lumiere. Il y a une stimulation par la lumiere verte. La production depend certainement d'un systeme phytochrome. La production d'ethylene est stimulee par les auxines, la cytokinine et par l'ion cobalt et elle est inhibee par l'ion cuivrique. L'action des ions metalliques est differente de celle observee chez les vegetaux superieurs. Le complexe enzymatique mis en jeu serait donc different. La production d'ethylene decroit avec l'enkystement le rougissement des cellules. Cependant, il existe un rythme circadien de production de l'ethylene et de synthese d'astaxanthine en fonction du cycle circadien naturel
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Patel, Sapna Bharat. "Electrophoretic and static light scattering measurements for equine serum albumin." Master's thesis, Mississippi State : Mississippi State University, 2008. http://library.msstate.edu/etd/show.asp?etd=etd-12102007-105847.
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Deen, Pascale Petronella Maria. "Exchange coupling and superconductivity in light rare earth alloys and superlattices." Thesis, University of Liverpool, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.272654.
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Wah, Jiing-Yeh. "Top Hat HELLISH (Hot electron light emitting and lasing in heterostructures)." Thesis, University of Essex, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274381.
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Li, Nola. "GaN on ZnO: a new approach to solid state lighting." Diss., Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/33840.
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The objective of the research was to develop high quality GaN epitaxial growth on alternative substrates that could result in higher external quantum efficiency devices. Typical GaN growth on sapphire results in high defect materials, typically 10⁸⁻¹⁰cm⁻², due to a large difference in lattice mismatch and thermal expansion coefficient. Therefore, it is useful to study epitaxial growth on alternative substrates to sapphire such as ZnO which offers the possibility of lattice matched growth. High-quality metalorganic chemical vapor deposition (MOCVD) of GaN on ZnO substrate is hard to grow due to the thermal stability of ZnO, out-diffusion of Zn, and H₂back etching into the sample. Preliminary growths of GaN on bare ZnO substrates showed multiple cracks and peeling of the surface. A multi-buffer layer of LT-AlN/GaN was found to solve the cracking and peeling-off issues and demonstrated the first successful GaN growth on ZnO substrates. Good quality InGaN films were also grown showing indium compositions of 17-27% with no indium droplets or phase separation. ZnO was found to to sustain a higher strain state than sapphire, and thereby incorporating higher indium concentrations, as high as 43%, without phase separation, compared to the same growth on sapphire with only 32%. Si doping of InGaN layers, a known inducer for phase separation, did induce phase separation on sapphire growths, but not for growths on ZnO. This higher strain state for ZnO substrates was correlated to its perfect lattice match with InGaN at 18% indium concentration. Transmission electron microscopy results revealed reduction of threading dislocation and perfectly matched crystals at the GaN buffer/ZnO interface showing coherent growth of GaN on ZnO. However, Zn diffusion into the epilayer was an issue. Therefore, an atomic layer deposition of Al₂O₃was grown as a transition layer prior to GaN and InGaN growth by MOCVD. X-ray and PL showed distinct GaN peaks on Al₂O₃/ZnO layers demonstrating the first GaN films grown on Al₂O₃/ZnO. X-ray photoelectron spectroscopy showed a decrese in Zn diffusion into the epilayer, demonstrating that an ALD Al₂O₃layer was a promising transition layer for GaN growth on ZnO substrates by MOCVD.
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Lauters, Michael E. "Organic Opto-Electronic Devices for Data Storage and Solid-State Lighting." Diss., The University of Arizona, 2006. http://hdl.handle.net/10150/193770.
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Metal/organic/indium tin oxide (ITO) structures, including OLEDs, are demonstrated to contain multiple nonvolatile conductance states that can be programmed by the application of an external bias above a certain threshold voltage (Vth). These conductance states are stable and in turn can be probed by the use of a bias lower in value than Vth. The unbiased retention time of states is greater than several weeks, and more than 48,000 write-read-rewrite-read cycles have been performed with minimal degradation. It is found that the programming of a continuum of conductance states is possible, and techniques to do so are outlined. The electrical conductivity of the highest and lowest states can differ by six orders of magnitude. Switching speeds below 50 ns are shown, resulting in an energy requirement of about 100 pJ to switch from one conductance state to another. The memory phenomenon is shown to be influenced by the active layer thickness and anode/surface roughness while temperature dependence is limited. The electrical characteristics of these devices are consistent with metal diffusion or filament phenomena found in metal-insulator-metal structures, suggesting a possible mechanism by which the states are stored.Electroluminescent devices employing several new organic-inorganic lumophore-functionalized macromolecules are presented. In this study, macromolecules incorporating several lumophores covalently bonded to the vertices of a cubical core structure based on Polyhedral Oligomeric Silsesquioxane (POSS) in multiple configurations are implemented as light-emitting centers. The hole-transporting polymer poly(N-vinylcarbazole) (PVK) and electron-transporting additive 2-(4-biphenylyl)-5-(4-tert-butylphenyl)1,3,4-oxadiazole (PBD) are used as a two-part host to enhance the carrier transport in these simple solution-processed single-layer devices. A study of energy transfer in several systems is carried out to understand the requirements needed to create white-light emission from a single macromolecule. A single macromolecule incorporating twenty-one blue and one yellow lumophore is shown to exhibit field-independent stable white-light electroluminescence with Commission Internationale de l'Eclairage (CIE) coordinates of (0.31, 0.37). An external quantum efficiency of 0.55 percent and a maximum brightness of 1600 cd/m2 are attained with simple solution-processed single-layer devices. High solubility and ease of purification give these macromolecule white-light emitters advantages over their small molecule and polymeric type counterparts.
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Kaufman, Sarah K. "Moments of Absorption." VCU Scholars Compass, 2008. http://scholarscompass.vcu.edu/etd/1133.
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Moments of Absorption explores the conceptual and visual themes that are presented in my MFA thesis exhibition. The research looks into the absorption of the nude subject, the gestures that communicate this absorption, and the domestic space as a stage for the presentation of these gestures. This work investigates a tension between the theatrical and the natural as represented by images.
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Rieländer, Daniel. "Quantum light source compatible with solid-state quantum memories and telecom networks." Doctoral thesis, Universitat Politècnica de Catalunya, 2016. http://hdl.handle.net/10803/404382.
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This PhD thesis is in the scope of experimental quantum communication. It deals with correlated photon pairs of which one photon is stored in a solid state device, while the other photon is at telecom wavelength. Quantum correlation between a photon at telecom wavelength and a photon stored in a quantum memory is an important resource for future applications like quantum repeaters, allowing the transmission quantum states over long distances.
During the first part of this thesis, a novel photon pair source has been developed, based on spontaneous parametric downconversion (SPDC) inside a bow-tie cavity. SPDC is a non-linear process which splits a pump photon sporadically into two correlated photons, called signal and idler photon. The source used in this work has been designed to be compatible with a solid state quantum memory based on a Praseodymium doped crystal, using the atomic frequency comp (AFC) protocol. This material has shown promising properties for classical light storage. However, it features a small storage bandwidth of 4 MHz at 606 nm, which sets stringent requirements for the photons to be stored. To match these requirements the SPDC process takes place inside a bowtie cavity which is resonant with the created signal and idler photons. The difference between storage wavelength and telecom wavelength (1436 nm in our case) leads to widely non-degenerate photon pairs. These double resonance leads to a strong clustering effect, which suppresses a high number of redundant spectral modes. The created photon spectrum is investigated carefully and consists of three clusters with few well separated modes. The width of each mode is around 2 MHz and matches the requirement for the quantum memory. Single mode operation was achieved by placing an additional Fabry-Perot cavity in the idler field at 1436 nm. This resulted in the demonstration of the narrowest photon pairs consisting of a spectral single mode, created by SPDC to date.
In the second part of the thesis, heralded single photons at 606 nm were created by the detection of a photon at 1436 nm. These heralded photons were then stored as collective optical excitations in a praseodymium crystal, using the AFC scheme. Non-classical correlation between the heralding photon and the stored and retrieved photons were observed for storage time up to 4 µs, 20 times longer than achieved in previous solid state quantum memory experiments.
Further development on the source, led to improved results, including an increase of coincidence count rate by one order of magnitude and a heralding efficiency of 28 %. The single photon nature of the heralded photon was also measured directly by showing strong antibunching of the 606 nm signal field. These improvements made the created photons compatible with the storage in the spin state of the praseodymium level scheme, using the full AFC protocol. That enabled an extended storage time of 11 µs with on demand readout of the stored photon.
The last part of the thesis explores another important resource for the distribution of quantum states with a quantum repeater, entanglement between the created photon pairs. Here we show a rather new approach of entanglement, which is well suited for narrow band photons based on frequency bins. We take advantage of the fact that the source naturally creates several energy correlated well separated frequency modes. In order to show the coherent superposition of the frequency modes, we use electro-optical modulators to coherently mix them. We could show high-visibility two-photon interference fringes, a strong indicator for entanglement in the frequency domain.
The results presented in this thesis open the door for the demonstration of entanglement between a solid-state spin-wave quantum memory and a photon at telecom wavelength. This represents an important step for the realization of quantum repeaters using solid state resources.Esta Tesis doctoral se encuentra en el área de la comunicación cuántica experimental. Trata de pares de fotones de los cuales uno está almacenado en una memoria cuántica de estado sólido y su pareja es compatible con redes telecom. Las correlaciones cuánticas entre un fotón telecom y un fotón almacenado en una memoria cuántica son un recurso importante para aplicaciones del futuro como un repetidor cuántico, que permite la transmisión de un estado cuántico hacia distancias largas. Durante la primer parte de la tesis, se ha desarrollado una fuente de fotones nueva basada en la conversión paramétrica espontanea (SPDC). SPDC es un proceso no lineal que divide esporádicamente un fotón de alta frecuencia en dos fotones correlacionados de baja frecuencia dentro de un rango de varios centenares de GHz, llamados fotones signal y idler. La fuente es compatible con una memoria cuántica de estado sólido basada en un cristal dopado con iones de praseodimio, usando el protocolo de pinta de frecuencias atómica (AFC). Este material ha demostrado propiedades extraordinarias para el almacenamiento de luz coherente. Sin embargo, ofrece un ancho de banda muy limitado de 4 MHz alrededor de una longitud de onda de 606 nm para el almacenamiento. Esto pone requisitos rigurosos a los fotones creados. Para cumplir con estos requisitos el proceso de SPDC se encuentra dentro de una cavidad de configuración ¿bow-tie¿. La cavidad es resonante con los fotones de signal y los de idler, que tienen longitudes de onda diferentes, que induce pares de fotones extensamente no-degenerados. Esta resonancia doble induce un fuerte efecto de agrupación de modos espectrales, que evita un gran número de modos redundantes. El espectro de los fotones creados se ha investigado detenidamente y contiene tres grupos con pocos modos espectrales. La anchura de cada modo es 2 MHz y cumple con los requisitos de la memoria cuántica. El filtraje de un modo único se realiza con una cavidad de Fabry-Perot adicional. El resultado es la demonstración de los pares de fotones más estrechos en un modo espectral individual creados por SPDC. En la segunda parte de la tesis se crean fotones individuales de 606nm anunciados por la detección de un fotón de 1436 nm. Estos fotones anunciados se almacenan como excitación colectiva óptica en un cristal de praseodimio usando el protocolo de AFC. Correlaciones no-clásicas entre el fotón almacenado y el fotón anunciante se observan hasta una duración de almacenado de 4 µs, 20 veces más largo que lo conseguido en experimentos previos con una memoria cuántica de estado sólido. Con el desarrollo posterior de la fuente se logró una tasa de coincidencia un orden de magnitud más alta y una eficiencia de anunciado del 28 %. La naturaleza del fotón individual anunciado se demostró por medido del "antibunching" del campo signal. Estos avances hicieron que los fotones creados fueran compatibles con el almacenamiento en el estado de spin del cristal de praseodimio usando el protocolo completo de AFC. Esto permitió que la duración de almacenamiento fuera extendida a 11 µs y también una lectura en demanda. La última parte de la tesis explora entrelazamiento en frecuencia entre los pares de fotones creados. Es un tipo de entrelazamiento, aún poco investigado, basado en los modos espectrales, que es muy conveniente para los fotones de banda estrecha. Tomamos la ventaja de que la fuente crea varios modos de frecuencias separados y correlacionados en energía. Para demonstrar una superposición coherente de los modos de frecuencia usamos moduladores electro-ópticos para mezclarlos coherentemente. Demostramos franjas de interferencia entre dos fotones con una alta visibilidad, un fuerte indicador del entrelazamiento en frecuencia.
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Benson, Samuel Lee. "Light harvesting and state transitions in Arabidopsis thaliana deficient in Lhca proteins." Thesis, University of Sheffield, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289600.
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Saunders, L. D. A. "Unsteady-state flow of light organic solvent wood preservatives into refractory softwood." Thesis, Imperial College London, 1988. http://hdl.handle.net/10044/1/47246.
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Jones, Billy Darwin. "Light-front Hamiltonian approach to the bound-state problem in quantum electrodynamics /." The Ohio State University, 1997. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487946103569513.
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Wong, Chi-kwong Patrick. "Development of transport policy for public light buses in Hong Kong." Click to view the E-thesis via HKUTO, 2003. http://sunzi.lib.hku.hk/hkuto/record/B31967383.
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Gardner, Douglas Walter McGregor. "Disinfection of solid surfaces by combinations of UV light and oxidation treatments." Thesis, Loughborough University, 1997. https://dspace.lboro.ac.uk/2134/28309.
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Combinations of ultraviolet light (UV) and the oxidising agents, hydrogen peroxide (H2O2) and ozone (O3), were evaluated for disinfecting solid surfaces. Studies were conducted using spores of the bacterium Bacillus subtilis (ATCC 6633) attached to materials ranging from filter papers and membranes to aluminium and PTFE. Techniques were developed for depositing, recovering and enumerating spores from these surfaces.