Dissertations / Theses on the topic 'Later stage development'
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Favato, Giampiero. "Parametric cost analysis of late-stage pharmaceutical development." Thesis, Brunel University, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.488727.
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Valentine, Gareth J. "Development of all-solid-state modelocked laser sources at 1.55 μM." Thesis, University of St Andrews, 1999. http://hdl.handle.net/10023/14790.
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This thesis concerns the generation of tunable ultrashort pulses near the 1.55 mum telecommunications window. Two principal laser systems are considered: i) the NaCl:OH colour-centre laser, which employs the technique of synchronously-pumped modelocking to generate tunable picosecond pulses and ii) the self-modelocked Cr4:YAG laser to generate femtosecond pulses tunable from 1.5-1.56 mum. Details are given for an all-solid-state cw and cw-modelocked pump source for Cr4:YAG and colour-centre lasers based on Nd:YAG. Fibre-coupled AlGaAs laser diodes are employed as the solid-state pump source to this laser. When operated cw, up to 8.5 W of linearly polarised output power in a TEM00 beam is obtained. A compact cw actively-modelocked Nd:YAG laser is described having a pulse repetition rate of 194 MHz. Pulse durations down to 34 ps and output powers up to 6.0 W are obtained from this system. An 82 MHz Nd:YVO4 laser is also detailed producing pulsewidths down to 75 ps and average output powers up to 3.5 W. The intrinsic noise source associated with the synchronous modelocking technique is discussed and a simple passive stabilisation scheme, coherent-photon-seeding (CPS), is described and applied to the synchronously-modelocked NaCl:OH laser. Results of a simulation of this laser are reported and a comparison is made with the practical observations of the stabilised laser. For the first time, theoretical and experimental evidence for the presence of high frequency pulse jitter in synchronously-pumped- modelocked (SPML) lasers is presented and the coherent photon seeding technique is shown to eliminate this noise. Details are also given for the construction of a compact, all-solid-state, femtosecond Cr4+:YAG laser. A design prescription for laser resonators having a high propensity for self-modelocking is presented and an unconventional 3-mirror resonator is adopted for optimised self-modelocked operation. Using this design, modelocked output powers up to 300 mW with 120 fs pulses from a compact, regeneratively initiated laser having a pulse repetition rate of 320 MHz is reported for 4.7W incident pump power. Self- modelocking is demonstrated for pump powers down to ~1W with this cavity design. A compact cavity design for self-modelocking is also assessed, with a footprint of just 20 X 25 cm, which places a prism in each cavity arm. 470 fs pulses at 220 mW average output power are reported.
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Sardana, Malvika. "Development of New Late-Stage Labeling Methods with Labeled Carbon and Fluorine-18." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASF001.
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Le marquage isotopique est un outil précieux pour la découverte de nouveaux médicaments. Nous présentons dans cette thèse la conception et l’application de méthodes de marquage tardif de molécules bioactives avec du carbone et du fluor. Les réactions de carbonylation utilisant le monoxide de carbone sont connues pour être compatibles avec un marquage isotopique tardif des substances bioactives dans des conditions douces. La première partie de cette thèse décrit une réaction de photocarbonylation à partir d’iodures d’alkyles catalysée par le palladium sous lumière visible. Cette réaction polyvalente utilisant le 9-methylfluorene-9-carbonyl chloride (COgen) et réalisée dans des conditions douces est compatible avec un marquage en carbone-14. La synthèse de COgen radioactif nécessitant plusieurs étapes, nos efforts ont porté sur la production de monoxyde de carbone marqué, par réduction du dioxyde de carbone correspondant avec un disilane. La dernière partie de la thèse aborde la synthèse d’un nouveau traceur marqué au fluor-18 pour la tomographie par émission de positrons, spécifique de la P-glycoprotéine (P-gp), un transporteur de la barrière hématoencéphalique. Nous avons ainsi marqué au fluor-18 le Crizotinib, anticancéreux approuvé pour le traitement du cancer du poumon non à petites cellules et qui voit son accumulation fortement diminuée par le P-gp. Les études de biodistribution et d’imagerie cérébrale chez les rongeurs sont actuellement en coursIsotope labeling is a crucial tool in drug discovery. Therefore, expanding the toolbox of a radiochemist with methods that allow late-stage labeling is highly important. The work presented in this thesis describes the development and utilization of late-stage labeling methods with carbon and fluorine. Carbonylation reactions with carbon monoxide are particularly known as mild and compatible with the late-stage labeling. The first part of the thesis describes the development of visible-light mediated palladium-catalysis using alkyl iodides as the coupling partner for the carbonylation. The mild and versatile radical aminocarbonylation protocol has shown good substrate compatibility. The use of 9-Methylfluorene-9-carbonyl chloride (COgen) allowed easy translation between unlabeled and labeled reaction. In order to bypass the synthesis of COgen which proceeds in two steps plus one step for the liberation of CO, we focused our efforts towards the one step reduction of labeled CO₂ to labeled CO using disilanes catalyzed by fluorides. The last part of this thesis discusses the development of a new positron emission tomography (PET) radiotracer for P-glycoprotein (P-gp), an active transporter at the blood-brain barrier. Crizotinib is an approved treatment for non-small cell lung carcinoma and its brain accumulation is restricted by P-gp. Crizotinib was successfully labeled with ¹⁸F, and rodent studies to map P-gp and improve the delivery of crizotinib to the brain are ongoing
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Canelli, Tommaso. "Development of tandem C-H borylation/functionalization procedures for late stage functionalization of compounds." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/9273/.
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The development of procedures for the iridium catalyzed C-H borylation of 1-aryl pyrazolopyrimidines and 1-aryl indazoles is reported. Investigation on the activity of the catalyst revealed the combination of an iridium (I) precursor and tetramethylphenantroline as the best catalytic system. Moreover, the procedures are regioselective resulting in the selective borylation of different C-H bonds within the substrates. The application of C-H borylation to late stage functionalization is demonstrated: a biologically active compound in AstraZeneca's project underwent tandem borylation/oxidation reaction, in order to obtain a functionalized product containing an OH group.
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Kim, Chan Kyu. "Development of bio-photonic sensor based on laser-induced fluorescence." Diss., Mississippi State : Mississippi State University, 2007. http://library.msstate.edu/etd/show.asp?etd=etd-11052007-092200.
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Prasankumar, Rohit Prativadi 1975. "Development and application of saturable absorbers to femtosecond solid-state laser mode-locking." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/29620.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2003.Includes bibliographical references (p. 209-228).
Semiconductor saturable absorbers have had a major impact on the field of ultrashort pulse generation by increasing the stability and reliability of ultrashort pulse lasers, making them more useful in many applications. These versatile devices can be grown both epitaxially with molecular beam epitaxy and non-epitaxially using RF sputtering. In this thesis, the development and application of both types of saturable absorbers to self-starting mode-locking in solid-state lasers was examined. The first part of this thesis describes the use of an epitaxially grown saturable Bragg reflector to mode-lock an extended cavity femtosecond Cr:LiSAF laser. Inexpensive single mode diodes were used as a pump source and a multi-pass cavity was used to lower the laser repetition rate. Pulses with durations of 39 fs and energies of 0.75 nJ were generated at an 8.6 MHz repetition rate. These pulse energies and durations are comparable to those produced from commercially available Ti:sapphire lasers that have a significantly higher cost. The second part of this thesis explored the further development and application of non-epitaxially grown semiconductor-doped silica films. A novel pump-probe system with independent pump and probe wavelength tunability from 700 to 1000 nm and a time resolution of 17 fs was developed for device characterization. The linear and nonlinear optical properties of InAs-doped silica films deposited by RF sputtering were characterized as a function of fabrication parameters, including nanocrystallite size, pump and probe wavelength relative to the absorption edge, and rapid thermal annealing temperature. Guidelines for the optimization of semiconductor-doped silica films for saturable absorber applications were extracted from the experimental data.
(cont.) Large nanocrystallites, high annealing temperatures, and an operating wavelength close to the absorption edge were found to optimize saturable absorber performance, with a low saturation fluence of 640 pJ/cm2 obtained at 1.54 grm. These saturable absorber devices were then designed to self-start mode-locking in a Cr:forsterite laser, obtaining self-starting 25 fs pulses with 91 nm bandwidth at 1.3 gm. These versatile devices can be designed for any solid-state laser system using the guidelines developed in this work and have the potential to replace epitaxially grown saturable absorbers in many applications.
by Rohit Prativadi Prasankumar.
Ph.D.
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Mujahid, Hana, Ken Pendarvis, Joseph Reddy, Babi Nallamilli, K. Reddy, Bindu Nanduri, and Zhaohua Peng. "Comparative Proteomic Analysis of Cotton Fiber Development and Protein Extraction Method Comparison in Late Stage Fibers." MDPI AG, 2016. http://hdl.handle.net/10150/618719.
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The distinct stages of cotton fiber development and maturation serve as a single-celled model for studying the molecular mechanisms of plant cell elongation, cell wall development and cellulose biosynthesis. However, this model system of plant cell development is compromised for proteomic studies due to a lack of an efficient protein extraction method during the later stages of fiber development, because of a recalcitrant cell wall and the presence of abundant phenolic compounds. Here, we compared the quality and quantities of proteins extracted from 25 dpa (days post anthesis) fiber with multiple protein extraction methods and present a comprehensive quantitative proteomic study of fiber development from 10 dpa to 25 dpa. Comparative analysis using a label-free quantification method revealed 287 differentially-expressed proteins in the 10 dpa to 25 dpa fiber developmental period. Proteins involved in cell wall metabolism and regulation, cytoskeleton development and carbohydrate metabolism among other functional categories in four fiber developmental stages were identified. Our studies provide protocols for protein extraction from maturing fiber tissues for mass spectrometry analysis and expand knowledge of the proteomic profile of cotton fiber development.
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Stehmann, Timo. "Development and optimisation of a solid-state pulsed power supply for a CO₂ TEA laser." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53359.
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Thesis (MSc)--Stellenbosch University, 2003.ENGLISH ABSTRACT: With technological advances in solid-state switches the modernization of conventional pulsed power supplies utilizing thyratrons has become possible. A novel pulsed power supply is designed where two series-stacked IGBTs (rated at 1700 V and 300 A each) are used to replace a thryatrondriven pulsed power supply for a mini CO2 TEA laser. The mini CO2 TEA laser is firstly characterized in order to optimize the design of the pulsed power supply. It is found that stable laser discharges can be obtained with electrode voltage rise-times of 150 ns or less. Furthermore, the optical output energy and the efficiency of the laser have been significantly increased by reducing the peaking capacitor size of the pulsed power supply. The two stacked IGBTs switch a C-C transfer loop and the generated pulse is stepped up by a pulse transformer and is compressed by a two-stage magnetic pulse compression unit. Theoretically and through measurements it is shown that automatic voltage sharing between the two IGBTs can be obtained if the turn-on time of the IGBTs is much faster than the transfer time of the switched C-C transfer loop. Lifetime tests reveal that high-power IGBTs are able to reliably switch pulses with peak currents between 4 and 5 times the rated average current of the device. Under laser fault conditions, i.e. laser arcing or missing laser discharges, the reliability of the pulser can be increased by using over-voltage snubbers. In addition, it was found that the internal diode of IGBT modules can eventually fail under the prevalence of laser fault conditions. A modular construction approach is used where components of the pulsed power supply are preassembled. A new rectangular layout of the magnetic pulse compression unit is utilized in order to minimize size and simplify the final construction and assembly.
AFRIKAANSE OPSOMMING: Nuwe ontwikkeling in vastetoestand-skakelaars het die modernisering van laser-pulskragbronne moontlik gemaak. ’n Nuwe kragbron wat gebruik maak van twee seriegeskakelde IGBT’s is ontwerp om ’n Tiratron-gedrewe laserkragbron te vervang, wat vir ’n mini-C02-TEA-laser gebruik word. Die laser is vooraf eers gekarakteriseer om sodoende die laserkragbron te optimeer. Daar is bevind dat stabiele laserontladings verkry kan word met spanningstygtye van 150 ns of minder. Verder kan die uittree-energie van die laser beduidend verhoog word deur die uittreekapasitore (eng.: peaking capacitors) van die laserkragbron te verminder. Die twee serie-geskakelde IGBT’s skakel ’n C-C oordraglus. Die spanning van die gegenereerde puls word deur ’n pulstransformator verhoog en die stygtyd van die puls word met ’n twee-stadium magnetiese pulskompressor verlaag. Teoreties en deur metings kan getoon word dat eweredige spanningsverdeling tussen die twee IGBT’s outomaties verkry kan word indien die skakeltye van die IGBT’s baie vinniger as die oordragstyd van die C-C oordraglus is. Toetse het getoon dat IGBT’s pulse met piekstrome van tussen vier tot vyf keer die gespesifiseerde gemiddelde stroom betroubaar kan skakel. Tydens laserfouttoestande kan die betroubaarheid van die IGBT verhoog word deur oorspanningsgapsers te gebruik, maar onder fouttoestande wat voortduur, kan die IGBT se interne diode vemietig word. Die komponente van die laserkragbron is as modules vervaardig, wat op ’n maklike wyse gemonteer kan word. ’n Nuwe reghoekige uitleg is gebruik vir die konstruksie van die magnetiese pulskompressor, waarmee die grootte van die pulskompressor geminimeer en die konstruksie vergemaklik is.
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Kirilov, Emil. "Development of necessary ion traps, vacuum and laser systems for photoionization, laser cooling and quantum state engineering of trapped Strontium ions." Diss., Restricted to subscribing institutions, 2007. http://proquest.umi.com/pqdweb?did=1481672311&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
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Matos, Carolina Thieleke da Silva Macedo. "Interaction of malaria parasites with host late endocytic and autophagic pathways is essential for Plasmodium liver stage development." Doctoral thesis, Faculdade de Ciências Médicas, 2013. http://hdl.handle.net/10362/12157.
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RESUMO: A Malária é causada por parasitas do género Plasmodium, sendo a doença parasitária mais fatal para o ser humano. Apesar de, durante o século passado, o desenvolvimento económico e a implementação de diversas medidas de controlo, tenham permitido erradicar a doença em muitos países, a Malária continua a ser um problema de saúde grave, em particular nos países em desenvolvimento.
A Malária é transmitida através da picada de uma fêmea de mosquito do género Anopheles. Durante a picada, os esporozoítos são injetados na pele do hospedeiro, seguindo-se a fase hepática e obrigatória do ciclo de vida. No fígado, os esporozoítos infetam os hepatócitos onde se replicam, dentro de um vacúolo parasitário (VP) e de uma forma imunitária silenciosa, em centenas de merozoitos. Estas novas formas do parasita são as responsáveis por infetar os eritrócitos, iniciando a fase sanguínea da doença, onde se os primeiros sintomas se manifestam, tais como a característica febre cíclica. A fase hepática da doença é a menos estudada e compreendida. Mais ainda, as interações entre o VP e os organelos da células hospedeira estão ainda pouco caracterizados. Assim, neste estudo, as interações entre os organelos endocíticos e autofágicos da célula hospedeira e o VP foram dissecados, observando-se que os anfisomas, que são organelos resultantes da intersecção do dois processos de tráfego intracelular, interagem com o parasita. Descobrimos que a autofagia tem também uma importante função imunitária durante a fase hepática inicial, ao passo, que durante o desenvolvimento do parasita, já numa fase mais tardia, o parasita depende da interação com os endossomas tardios e anfisomas para crescer. Vesiculas de BSA, EGF e LC3, foram, também, observadas dentro do VP, sugerindo que os parasitas são capazes de internalizar material endocítico e autofágico do hospedeiro. Mais ainda, mostramos que esta interação depende da cinase PIKfyve, responsável pela conversão do fosfoinositidio-3-fosfato no fosfoinositidio-3,5-bifosfato, uma vez que inibindo esta cinase o parasita não é capaz de crescer normalmente. Finalmente, mostramos que a proteína TRPML1, uma proteína efetora do fosfoinositidio-3,5-bifosfato, e envolvida no processo de fusão das membranas dos organelos endocíticos e autofágicos, também é necessária para o crescimento do parasita. Desta forma, o nosso estudo sugere que a membrana do VP funde com vesiculas endocíticas e autofágicas tardias, de uma forma dependente do fositidio-3,5-bifosfato e do seu effetor TRPML1, permitindo a troca de material com a célula hospedeira.
Concluindo, os nossos resultados evidenciam que o processo autofágico que ocorre na célula hospedeira tem um papel duplo durante a fase hepática da malaria. Enquanto numa fase inicial os hepatócitos usam o processo autofágico como forma de defesa contra o parasita, já durante a fase de replicação o VP funde com vesiculas autofágicas e endocíticas de forma a obter os nutrientes necessários ao seu desenvolvimento.--------- ABSTRACT: Malaria, which is caused by parasites of the genus Plasmodium, is the most deadly parasitic infection in humans. Although economic development and the implementation of control measures during the last century have erradicated the disease from many areas of the world, it remains a serious human health issue, particularly in developing countries.
Malaria is transmitted by female mosquitoes of the genus Anopheles. During the mosquito blood meal, Plasmodium spp. sporozoites are injected into the skin dermis of the vertebrate host, followed by an obligatory liver stage. Upon entering the liver, Plasmodium parasites infect hepatocytes and silently replicate inside a host cell-derived parasitophorous vacuole (PV) into thousands of merozoites. These new parasite forms can infect red blood cells initiating the the blood stage of the disease which shows the characteristic febrile malaria episodes. The liver stage is the least characterized step of the malaria infection. Moreover, the interactions between the Plasmodium spp. PV and the host cell trafficking pathways are poorly understood. We dissected the interaction between Plasmodium parasites and the host cell endocytic and autophagic pathways and we found that both pathways intersect and interconnect in the close vicinity of the parasite PV, where amphisomes are formed and accumulate. Interestingly, we observed a clearance function for autophagy in hepatocytes infected with Plasmodium berghei parasites at early infection times, whereas during late liver stage development late endosomes and amphisomes are required for parasite growth. Moreover, we found the presence of internalized BSA, EGF and LC3 inside parasite vacuoles, suggesting that the parasites uptake endocytic and autophagic cargo. Furthermore, we showed that the interaction between the PV and host traffic pathways is dependent on the kinase PIKfyve, which converts the phosphoinositide PI(3)P into PI(3,5)P2, since PIKfyve inhibition caused a reduction in parasite growth. Finally, we showed that the PI(3,5)P2 effector protein TRPML1, which is involved in late endocytic and autophagic membrane fusion, is also required for parasite development. Thus, our studies suggest that the parasite parasitophorous vacuole membrane (PVM) is able to fuse with late endocytic and autophagic vesicles in a PI(3,5)P2- and TRPML1-dependent manner, allowing the exchange of material between the host cell and the parasites, necessary for the rapid development of the latter that is seen during the liver stage of infection. In conclusion, we present evidence supporting a specific and essential dual role of host autophagy during the course of Plasmodium liver infection. Whereas in the initial hours of infection the host cell uses autophagy as a cell survival mechanism to fight the infection, during the replicative phase the PV fuses with host autophagic and endocytic vesicles to obtain nutrients required for parasite growth.
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Hageman, William. "THE DEVELOPMENT OF SCALABLE PUMP TECHNIQUES FOR GG IAG FIBER LASERS AND PASSIVE ATHERMALIZATION TECHNIQUES FOR SOLID STATE LASER." Doctoral diss., University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3639.
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This dissertation consists of two parts: research pertaining to the development of scalable pump techniques for gain guided index-antiguided fiber lasers and research relating to the development of passive athermalization schemes for solid state lasers. The first section primarily details the development of a side pump scheme that allows for power scaling of gain-guided index anti-guided fibers. While these fibers have been demonstrated in past research, none have used a pump technology capable of pumping with the efficiencies, uniformity, and necessary length to allow for scaling of the fiber lasers to high output powers. The side pumped scheme developed in this section demonstrates a 6 W output power fiber laser with room for improvement in efficiency and beam quality. The second section details work done on the development of technologies for passively athermalizing the output of solid state laser systems. Techniques for passively removing the dependence of laser output power/energy on the operating temperature of the laser system promise to reduce the weight, power consumption, and cost of fielded laser systems. Methods for achieving passive athermalization are discussed, as well as prior research in laser athermalization, background theory, enabling technologies, and experimental results. This work provides the basis for continued research of passive athermalization and the eventual demonstration of this technology.Ph.D.
Optics and Photonics
Optics and Photonics
Optics PhD
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Paul, Thomas Alfred. "Development and spectroscopic applications of a solid-state vacuum ultraviolet laser system in atomic and molecular physics /." Zürich : ETH, 2008. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=17814.
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Gottschalk, Adrian Hedley Benjamin 1975. "Improving the efficiency of the later stages of the drug development process : survey results from the industry, academia, and the FDA." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/16699.
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Thesis (S.M.)--Harvard-MIT Division of Health Sciences and Technology, 2004.Includes bibliographical references (p. 65).
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Drug development in the United States is a lengthy and expensive endeavor. It is estimated that average development times range from eleven to fifteen years and exceed costs of one billion dollars. The development pathway includes basic scientific discovery, pre-clinical testing in animals, clinical development in humans, and an application process. The Food and Drug Administration is responsible for the oversight and approval of drugs going through this process. Numerous financial and economic studies have been conducted that show the benefits to accelerating the drug development process. In 1992, the United States Congress enacted the Prescription Drug User Fee Act I, which mandated faster response times from the FDA in return for user fee payments to the FDA by the drug developing companies. Data on approval times for new drugs indicate that this process was indeed shortened. In contrast, the average drug development process prior to the filing of an application has been increasing in cost and time. The first purpose of this research is to quantify the benefits of accelerated new drug application review time under the Prescription Drug User Fee Acts I and II. The second purpose of the research is to investigate what industry and the FDA can do together to reduce the development process time between the IND and NDA without compromising patient safety and welfare, specifically the Phase II, Phase III, and NDA components. The research indicates that PDUFA has improved approval times in a statistically significant way. Furthermore, the financial and social benefits as measured using net present value have far exceeded the PDUFA costs. Quantitative and qualitative surveys of fifty individuals in large pharmaceutical and biotech companies
(cont.) resulted in the identification of several significant opportunities and useful suggestions for reducing development times in Phase II, Phase III, and the NDA. Specifically, company interviewees indicated that they were willing to pay additional monies for increased interaction and communication with the FDA from Phase II through the NDA in hopes of reducing information asymmetry and increasing information transparency. Other recommendations included a mandatory audit and review of a sample of NDAs post approval to identify best practices, implementation of metrics and performance tracking during clinical phases, and implementation of consistent project management and communication standards across therapeutic divisions.
by Adrian Hedley Benjamin Gottschalk.
S.M.
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Black, Juli. "Developmental Patterns of Metabolism and Hematology in the Late Stage Chicken Embryo (Gallus Domesticus) at Two Incubation Temperatures." Thesis, University of North Texas, 2003. https://digital.library.unt.edu/ark:/67531/metadc6150/.
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How temperature affects physiological development in the chicken embryo is unknown. Embryos incubated at 38°C or 35°C showed no difference in growth or survival. The time to hatching was longer in 35°C than 38°C embryos (23.7 vs. 20.6 days), but unaffected was the relative timing of appearance of developmental landmarks (internal, external pipping). At stage 43-44, 38°C embryos maintained oxygen consumption around 1 mL/g/h despite acute temperature reduction (suggesting thermoregulatory maturation), unlike 35°C embryos. In 35°C embryos the lower oxygen-carrying capacity and temperature insensitive blood O2 affinity (P50 about 30 mmHg) may restrict O2 delivery to tissues, limiting metabolism during decreased ambient temperature. Reduced incubation temperature retards normal hematological and thermoregulatory development.
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Thurlow, Meghan Elizabeth. "Free Radicals and Reactive Intermediates in the Boundary Layer: Development and Deployment of Solid-State Laser Based Instrumentation to Measure Part per Trillion Mixing Ratios of Iodine Monoxide and Glyoxal In Situ." Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10668.
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Advances in spectroscopic measurement techniques enabling highly accurate measurements of trace gases in the atmosphere are critical for furthering our understanding of the chemical processes that impact both climate and human health. This dissertation presents the development and deployment of laser-based instruments for measuring parts per trillion (pptv) concentrations of iodine monoxide and glyoxal. Iodine, which is primarily released from oceanic sources, is highly reactive in the atmosphere. Despite its trace concentrations, iodine plays a potentially important role in ozone destruction, the catalysis of mercury deposition, and the formation of marine clouds. An in situ instrument to detect iodine monoxide (IO) using laser-induced fluorescence was developed and then validated during a deployment to the Shoals Marine Laboratory (Appledore Island, ME) in August and September 2011. Mixing ratios up to 10 pptv of IO were observed with a strong tidal dependence. The instrumental detection limit \((3\sigma)\) of 0.36 pptv in 1 minute is indicative of unprecedented sensitivity. Glyoxal, the smallest alpha-dicarbonyl, serves as an atmospheric tracer of both the oxidation of biogenic volatile organic compounds in forest environments as well as secondary organic aerosol. Modeling studies indicate that production of glyoxal on a global scale is driven primarily by biogenic emissions, specifically emissions of isoprene. However, measurements of glyoxal in environments where isoprene dominates its production are limited. An instrument to detect glyoxal in situ by laser-induced phosphorescence was developed. The 3σ limit of detection of this instrument was 3.9 pptv in 1 minute. During July and August 2009, gas-phase measurements of glyoxal were made during the Community Atmosphere-Biosphere Interactions Experiment at the PROPHET tower in an isoprene-dominated forest site in northern Michigan. Additional measurements made throughout the campaign have been used to constrain a box model using the Master Chemical Mechanism. The model over-predicts glyoxal relative to the observed mixing ratios. Theoretically predicted reaction pathways implemented in many isoprene oxidation schemes exacerbate this disagreement.Chemistry and Chemical Biology
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Lemes, Hamawaki Raphael. "EVALUATION OF DI-NITROGEN FIXATION IN EARLY AND LATE DEVELOPMENTAL STAGES OF SOYBEAN (Glycine max [L.] Merr.)." OpenSIUC, 2018. https://opensiuc.lib.siu.edu/dissertations/1592.
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Nitrogen (N) is present in proteins, enzymes, cell structures, purines and pyrimidines in DNA and RNA molecules, photosynthetic pigments, and several other types of molecules in all living organisms. Nonetheless, even though N makes up more than 78% of the atmosphere, it is reported to be the most frequent deficient nutrient in plants. Nitrate (NO3-) and ammonium (NH4+) are the N forms absorbed by plants from soil, but legume crops can establish symbiotic relationships with rhizobia bacteria, and fix N2 from the atmosphere. In soybean, increasing yield and protein content are raising the crop's N requirement; therefore, enhanced N2 fixation is seen as a reliable path to avoid the use of N fertilizers. In this study, the objective was to perform a comprehensive screening in greenhouse and field conditions of soybean genotypes for traits related to N2 fixation. The purpose was to identify among the soybean genotypes different N2 fixation profiles at early and late stages, as well as to investigate their capacity to accumulate above-ground N and supply carry-over N to following crops. The results showed different profiles among the soybean genotypes for early and late N2 fixation capacity, both in greenhouse and field evaluations. Different traits were correlated to either early or late N2 fixation activity. Soybean and winter-rye shoot dry mass were evaluated in the field to assess above-ground N accumulation and carry-over N, respectively. Soybean genotypes were identified with specific capacities to accumulate N in above-ground biomass or supply N to winter-rye. The patterns of N2 fixation identified in this study, as well as the different abilities to accumulate N above-ground or supply N to following crops, could assist in the selection of superior lines with improved N2 fixation capacity.
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Osborne, Jason Matthew. "The development of church/state relations in the Visigothic Kingdom during the sixth century (507-601)." Diss., University of Iowa, 2016. https://ir.uiowa.edu/etd/3156.
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In the year 589 Reccared, king of the Visigoths, called together leaders of the Catholic Church and the Visigothic nobility to meet at the Third Council of Toledo. That council marked a dramatic change in the Visigothic Kingdom and began a collaboration between the Catholic Church and the Visigothic royal government that would come to define the kingdom, and has forever colored our view of the history of Spain. This dissertation will attempt to place the events that occurred at the Third Council of Toledo into the larger context of the sixth century and will show that the union between the Catholic Church and the Visigothic royal government that occurred at Toledo III was the result of a connection between two longstanding forces in society: the efforts of a small number of provincial bishops to purify society through strict, orthodox Catholicism and the efforts of a few Visigoth monarchs to centralize the kingdom and create a political entity that would be the natural heir to official Roman legitimacy in the west as well as offer a counterbalance to the Eastern Roman Empire. Further, it will draw some connections between the work of the Catholic Church in the Suevic Kingdom, the other Germanic Kingdom that existed on the Iberian Peninsula during the sixth century, and the the Third Council of Toledo. Finally, it will show that in the immediate aftermath of the Third Council of Toledo the bishops were disappointed to find that the introduction of coercive power as a tool of instruction for bishops proved largely unworkable in the short term which led them to abandon some of their new found powers.
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Lee, Daphnee Hui Lin. "From Cradle to Playpen: the management of Chineseness in developmental state Singapore." Phd thesis, Canberra, ACT : The Australian National University, 2010. http://hdl.handle.net/1885/49385.
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The way Chineseness is managed by the state in ethnic Chinese majority nations is examined as a late-industrializing initiative. Using Singapore as the case study, identifications with Chineseness were studied for the key themes within late-industrializing discourse constructions. Chinese Singaporean respondents were asked for their interpretation of Chineseness in relation to their Western expatriate and Chinese mainlander colleagues. In some cases, Orientalist constructions emerged. This inquiry found the moderating factors of Orientalist discourse replications to be the respondent’s childhood socioeconomic background and linguistic primacy. The findings lent insights to the persistence of Orientalist constructions amongst individuals in late-industrializing societies. Insights as to how late-industrializing discourses constructions are moderated by factors distinctive from first-mover ones were sought. These insights enrich the theoretical framework of nation branding studies, a recent offshoot of nation studies with a marketing slant. Sociological considerations on the reproduction of late-industrializing predispositions were integrated through the concept of marcotted developmentalism. Marcotted developmentalism is advanced as the thesis’ conceptual framework. It explains the mediation of the late-industrializing landscape by two distinctive features. Firstly, ethnic management initiatives communicate the urgency of accelerated economic development amongst late-industrializing societies. Secondly, it emphasizes the presence of dual hegemony (i.e. Western dominance and Chinese ascendency) within the late-industrializing political economy.
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Nogueira, Gustavo Bernardes. "Desenvolvimento de lasers no azul, a partir da geração de segundo harmônico de um laser de Nd:YAG operando em 946 nm." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-08112010-165940/.
Full textAbstract:
Lasers emitindo no azul vêm sendo largamente utilizado em diversas aplicações como por exemplo, blu-ray, displays, e podem representar uma excelente fonte de bombeio para o meio ativo Ti:safira. Neste trabalho utilizamos um cristal de Nd:YAG, com diffusion bonded end-caps e um bombeamento com diodo semicondutor no comprimento de onda de 803,2 nm, dessintonizado do pico de absorção 808 nm de neodímio, a fim de minimizar os efeitos de lente térmica do Nd:YAG. Dessa forma, conseguiu-se uma melhor distribuição de temperatura dentro do cristal. Testando diferentes raios de curvatura para os espelhos da cavidade, obteve-se a melhor relação entre a cintura do feixe de bombeio e feixe laser, alcançando 6,75 W cw (continuous wave) de potência de saída laser em 946 nm e slope efficiency de 48%. Em um segundo passo foi inserido, em diferentes tipos de cavidades, um cristal dobrador de freqüência para obtenção de emissão no azul em 473 nm, e a potência de saída azul foi medida em função da potência absorvida.Blue lasers have attracted much attention for applications such as blu-ray, displays and as pumped source for the Ti:sapphire laser. A Nd:YAG crystal with diffusion bonded end-caps was used together with a pump wavelength of 802,3 nm, detuned from the absorption peak at 808 nm in order to minimize the thermal lens effect by providing for a better temperature distribution inside the crystal. Using different input mirror radii, the best relation between pump waist and laser was achieved in a linear cavity and resulted in 6.75W cw (continuous wave ) laser power at 946 nm and slope efficiency of 48%. In a second step, a second harmonic generation crystal for blue emission at 473 nm was inserted into different types of resonators, and the blue output power at 473 nm was measured as a function of absorbed pump power.
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Rethwisch, M. D., M. Reay, G. Chaffin, R. Perez, J. Grudovich, J. Wellman, and E. Hawpe. "Late Planted DPL451BR Cotton Responses to Plant Growth Enhancement Products Applied at Three Crop Development Stages in Palo Verde Valley, 2003." College of Agriculture, University of Arizona (Tucson, AZ), 2004. http://hdl.handle.net/10150/198128.
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An experiment to investigate the effects of several plant growth enhancement products (AuxiGro7 WP, FirstChoice7 Bollster, CalMax, FoliGro7 BollSet) on DPL 451BR was conducted in the Palo Verde Valley. The cotton field chosen for this project was planted in April 2003, and flowering and boll/lint production was highly affected by summer heat, therefore product effectiveness was tested under the extreme high temperatures conditions that existed in 2003. Products were applied July 11 (shortly after first bloom), August 1st and/or August 15. Three rates (1, 2, 4 oz./acre) of AuxiGro7 WP were applied at each date, although just a single rate of other products was evaluated. Data collected included plant mapping following the first two application dates as well as lint yield and quality at harvest on October 20-23. Data indicated rate effects for treatments containing AuxiGro7 WP as noted in response to applications on August 1 (retention rates) and August 15 (cotton quality factors). These responses were signficantly different than the untreated check, and were often signficantly different than the Bollster fertilizer treatment itself as though Bollster was also included with AuxiGro7 WP treatments. Although yields for any treatment and the untreated check were not significantly different, previously noted differences for retention for the AuxiGro7 WP treatments may not have been realized due to the high temperatures and extended periods of not only Level 1 but Level 2 stress during the course of the experiment. Cotton values per acre were highest ($609.85/acre) in the 4 oz/acre of AuxiGro7 applied on August 15, due to highest valued lint as a result of micronaire of 5.2 combined with increased fiber strength and fiber length. Application of CalMax resulted in a significant increase in fiber strength following two applications of 4 oz./acre of AuxiGro7 + Bollster, but CalMax following two applications of Bollster did not affect fiber strength when compared with each of the two application treatments. A third application of FoliGro7 BollSet was detrimental for cotton yields and strength compared with only two applications of this product, although both treatment regimens resulted in shorter fibers that were not quite as strong as the untreated check.
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Stewart, Brian K. "Development of a Thin-Film Evaporative Cooling System for a High Energy Thulium Holmium: Lutetium Lithium Flouride Solid-State Laser Oscillator Crystal." Thesis, Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/6973.
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The feasibility and critical design parameters for the development of a thin-film evaporative cooling concept for a high energy, pulsed solid-state laser oscillator were investigated. The scope of the investigation was broad, and a multidisciplinary approach was employed. No contra-indicators for the feasibility of the proposed system were revealed.
A 1-dimensional two-fluid was developed to model the hydrodynamic flow and heat transfer assuming a constant wall heat flux. This analysis produced nominal pressure drops for the flow required, indicating nominal power will be required to transport fluid across the crystal surface.
Interfacial experiments reveal that the laser crystal material has a surface energy of approximately 30 mN/m, and is highly dispersive in nature.
Design rules to allow for the orthotropic thermal expansion of the crystal rod surrounded by a thin metal sleeve were developed to support the design of a hermetic crystal-metal seal. The results indicate that commercially pure nickel produces minimal joint stresses for large thermal excursions.
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Stewart, Brian K. "Development of a thin-film evaporative cooling system for a high energy thulium holmium lutetium lithium fluoride solid-state laser oscillator crystal /." Available online, Georgia Institute of Technology, 2005, 2004. http://etd.gatech.edu/theses/available/etd-12032004-114711/unrestricted/stewart%5Fbrian%5Fk%5F200505%5Fmast.pdf.
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Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2005.S. Mostafa Ghiaasiaan, Committee Chair ; Sheldon M. Jeter, Committee Member ; Said I. Abdel-Khalik, Committee Member. Includes bibliographical references.
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Quach, Judy Tinh Nhi. "The validity of the Modified Ordinal Scales of Psychological Development (M-OSPD) for use with people in late stages of Alzheimer disease." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0015/MQ47084.pdf.
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Petrova-Mayor, Anna. "Development of an eye-safe solid-state tunable laser transmitter around 1.45 my m based on Cr 4+:YAG crystal for lidar applications." [S.l. : s.n.], 2008. http://nbn-resolving.de/urn:nbn:de:bsz:100-opus-2782.
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BERECZKI, ALLAN. "Desenvolvimento de um laser DPSSL polarizado com mais de 100 W de potência e parâmetro de qualidade próximo de um." reponame:Repositório Institucional do IPEN, 2016. http://repositorio.ipen.br:8080/xmlui/handle/123456789/26822.
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A operação dinamicamente estável com zonas conjuntas foi obtida para um ressonador laser contendo dois bastões de Nd:YAG com módulos laser comerciais. O ressonador não polarizado gerou 115 W de potência no modo transversal fundamental TEM00. Quando polarizado por lâmina de Brewster atingiu 100,5W de potência de saída com 91% de polarização. Quando o ressonador foi polarizado com um polarizador de filme fino, obteve-se melhora na qualidade de feixe e um aumento na polarização, com o valor de M2 sendo 1,56 e 1,84 nas direções x e y respectivamente com 95,4% de polarização. A potência de saída foi, ao nosso conhecimento, a mais alta obtida para lasers polarizados operando no modo fundamental e usando módulos lasers comerciais de Nd:YAG bombeados lateralmente por diodos sem nenhuma preparação especial.
Dissertação (Mestrado em Tecnologia Nuclear)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Velissariou, Panagiotis. "Development of a Coastal Prediction System That Incorporates Full 3D Wave-Current Interactions on the Mean Flow and the Scalar Transport With Initial Application to the Lake Michigan Turbidity Plume." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1229959016.
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Mahadevan, Pradeep. "Analysis of layer development and fusing for 3D laser printing." 2003. http://www.lib.ncsu.edu/theses/available/etd-05062003-080231/unrestricted/etd.pdf.
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Wang, Yu-Siang, and 王昱翔. "Development of Laser Direct Writing Equipment of Nano Stage." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/46755r.
Full textAbstract:
碩士國立虎尾科技大學
機械與機電工程研究所
99
This research project in title of “Laser Direct Writing Processing Equipment for Periodic Nanostructure Pattern” integrated the technologies of the hybrid long-stroke precision nano-stage design, the multi-DOF heterodyne interferometer feedback control system, and the novel laser direct writing lithography instrument. The hybrid long-stroke multi-axis precision nano-stage formed by an H-type long-stroke nano-stage and a nano piezo-stage. The multi-DOF heterodyne interferometer feedback control system uses dual-frequency laser interferometer for the measurement of X and Y axis position and θz angle error of the nano-stage. The ovel laser direct writing lithography instrument includes blue laser direct writing head, FPGA interface and servo control main board. Finally, the system integration and relevant tests have been completed as well. This equipment have been working to generate increase writing speed, precision and range. In this research, the integration of the Laser Direct Writing Processing Equipment can improve the process speed, precision and range, overcome the optical limit of interference to reduce the writing spot, generate arbitrary patterns, and cut down the equipment cost.
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Yu-Tsung and 李育宗. "Development of 266nm all Solid-State Laser." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/63240538479794183153.
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碩士國立中山大學
物理學系
87
Solid state lasers possess unique status in the history of laser development. In 1960's, the first laser successfully developed laser is a solid state ruby laser. Despite of solid-state lasers' limited coverage of optical spectrum, they have several advantages, such as long life time, high stability, and high conversion efficiency. Extending available wavelengths of solid state lasers is one of the major on-going efforts of photonic community. In this dissertation, resonant enhanced second harmonic generation (SHG) in a BBO nonlinear optical crystal is employed to convert the output of a diode-pumped solid state laser at 532 nm into 266nm. We have built both the theoretical model and the experimental setup to realize a continuous wave ultraviolet laser. Coupling efficiency as high as 93% is demonstrated.
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Vincent, Nicola Caroline. "Evolving consciousness in leaders: promoting late-stage conventional and post-conventional development." Thesis, 2014. http://hdl.handle.net/2440/87864.
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Loevinger’s (Loevinger & Blasi, 1976; Loevinger, 1987) theory of consciousness development provides a stage model for understanding psychological growth through the lifespan. Many constructive developmental theorists have argued that resolution of the adaptive challenges now faced by organisations, communities and globally, requires leadership from people who have reached Loevinger’s post-conventional stages of adult psychological development. As yet, there is little empirical evidence to explain why so few individuals attain these post-conventional stages, and whether or how such development may potentially be facilitated. The research program presented in this dissertation aimed to help address this gap in the literature by furthering an understanding of factors influencing consciousness development, particularly to the first post-conventional level. It was undertaken in three stages, utilising a mixed methods approach, and resulting in production of three journal articles (one published, and two under review with international journals). The first study explored whether personality preferences and combinations thereof (as measured by the Myers-Briggs Type Indicator or MBTI) are associated with higher consciousness levels (as measured by the Washington University Sentence Completion Test or WUSCT) and whether particular personality preferences might act as inhibiting or facilitating factors in consciousness development. Participants were 374 adults participating in Australian community leadership programs (CLPs) or professional management programs. After adjusting for age and education, a preference for Intuition was associated with significantly higher consciousness development on program entry and with greater consciousness development during the programs. These results provide support for Manners’ and Durkin’s (2000) proposal that dispositional personality characteristics may enhance or constrain consciousness development. The second study involved 335 adults and explored the impact on consciousness development of participating in either standard or enhanced Australian CLPs (compared to control programs). Aligned with Manners’ and Durkin’s (2000) conceptual framework, CLPs offer experiences that are interpersonal, emotionally engaging, personally salient and structurally disequilibriating for later conventional consciousness stages. Enhanced CLPs include additional psychosocial challenges. Standard and enhanced CLPs were successful in facilitating consciousness development within the conventional stages. Enhanced CLPs were significantly more successful in triggering post-conventional development, and specifically among those participants who had a preference for MBTI Sensing. The third study involved qualitative analysis of survey data from 84 individuals graduating from three enhanced CLPs. It found alignment with Loevinger’s (Loevinger & Blasi, 1976; Loevinger, 1987) theory and Manners’ and Durkin’s (2000) conceptual framework in terms of the changes that participants who had shifted a stage of consciousness (Shifters) had noticed in themselves, and the aspects of the CLP they believed had been important in facilitating their development. Shifters were also significantly more likely than non-shifters to cite work changes and challenges when asked about other influences that may have impacted their readiness for development. Those with an MBTI Sensing preference were significantly more likely to report factors that were supportive of their development than those with an MBTI preference for Intuition. Together, these studies contribute to a more sophisticated understanding of the factors that may facilitate or inhibit consciousness development (particularly to post-conventional stages). Implications for the design of, and selection of participants for, leadership programs to promote such development are discussed, and future research directions are indicated.Thesis (Ph.D.) -- University of Adelaide, School of Psychology, 2014
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Yang, Hao-Wen, and 楊皓文. "Development of a Sequential Two-stage Layer Forming Rapid Prototyping Machine." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/25181023587143341472.
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碩士國立成功大學
機械工程學系碩博士班
94
The Rapid Prototyping (R.P.) technology which is generally used to manufacturing a three-dimensional solid part is based on the layer forming method. The R.P. technology had been devised in 1978 and its advantages are easy to achieve the purposes of saving time and cost. In recent years, many kinds of commercially available machines are invented successively. However, all the existing R.P. devices had some faults. Thus, in this thesis, a new type of R.P. process is proposed to improve the quality of the articles and decrease the cost of the current R.P. machines. The process of the new R.P. is called “Sequential Two-stage Layer Forming Process”. The process started from using a spray gun to spread a thin layer of polymeric material on the forming bed, followed by using the two-stage forming method to carry out the layer manufacturing process. Based on the new idea, this thesis had developed, designed and fabricated a brand new machine. With this machine, the concept of the new R.P. machine which is expected to achieve the target of low-cost and fast process is implemented.
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WU, JHONG-SYUAN, and 吳鍾萱. "Development of two-stage RF power supply for driving CO2 laser." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/44393100389747264982.
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碩士國立聯合大學
光電工程學系碩士班
105
In this thesis, we propose a two-stage RF power supply that drives carbon dioxide laser. The power supply is based on Metal Oxide Semiconductor Field-Effect Transistor(MOSFET). RF power supply is combine with one stage oscillator and one stage amplifier. We apply MRF148 with our oscillator. The oscillation frequency is 100MHz. Maximum power is up to 30W in output continuous wave and peak power have 35W. In two stage of amplifier we use MRF150 and design push-pull structure of amplifier. The purpose is reduce the series of high-power RF power supply and circuit size. The maximum output is up to 300 W and efficiency is 78.5%. The standing wave ratio is 1:2. In our control circuit part we combine Pulse Width Modulation(SG3525), optical coupler(TPL250) and high side driver(IR2117). We use Pulse Width Modulation to control oscillator signal, then amplified by a push-pull amplifier. The result of high-power RF signal to stimulate carbon dioxide laser. When gas dissociation, we observe the gas discharge of carbon dioxide.
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Liou, Sing-Yan, and 劉興諺. "Development of New Type Linear Stage with Double-Layer Throttling Porous Aerostatic Bearing." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/54342974701647728469.
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碩士國立勤益科技大學
機械工程系
102
The structure configuration of air flotation platform is usually designed with low gravity center, low geometric error, low fever errors and symmetrical structure. Especially, the mobile component is mostly made of lightweight aluminum to reach a low inertia for high precision and high speed motion control. As a consequence, the linear stage with air bearing has been widely used in the fields of optical instruments, precision medical equipment, semiconductors, subtle elements etc. Such a stage also greatly adopted in precision optoelectronic semiconductor process equipment or testing equipment. This study was aimed to design a high precision aerostatic linear stage based on the newly developed double-layer throttling porous aerostatic bearing, which was created by GMT company collaborated with Metal Industries Research and Development Centre. The mobile platform was made of alumina material with the use of ultra-precision diamond machining. A weight reduction 65% of the mobile stage was achieved due to the use of structural material of alumina alloy, instead of the originally steel material. The straightness accuracy of precision linear aerostatic stage was shown to be 0.7 um, which was based on the high accuracy, good surface roughness and lighter components. The geometric accuracy has been proven to be below 1um/100mm and surface roughness below 0.1um. In addition, the other key feature of this stage is the combination of the aerostatic porous double-throttling technology with the microwell array aluminum board, which effectively enhances the rigidity of the loading capacity due to the array of pore distribution and number density to regulating fluid properties. It follows that rigidity was increased by 3.6 times. As a whole, the prototype of the newly designed aerostatic linear stage developed in this study has been demonstrated to show a better performance as expected. It is believed that a more complete linear stage can further be developed based on this prototype. The technology regarding the double-layer throttling porous aerostatic bearing can also be widely applied to develop other precision instruments in the field of manufacturing industry.
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Chen, Ching-Nien, and 陳慶年. "Development of a solid-state three-wavelength laser with volume Bragg gratings." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/93288472790227841820.
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碩士國立中央大學
光電科學與工程學系
104
Solid-state dual-wavelength lasers were constructed using a Nd:GdVO4 as the gain medium. The output couplers used in these laser cavities were temperature controlled volume Bragg gratings. The gain of the laser cavities was adjusted by changing the temperatures of the VBGs. Temperature adjustment mainly results in thermal expansion of the VBGs, and shifts the corresponding diffraction spectrums, which will then alter the corresponding emission cross section of the laser outputs. Through this method, three dual-wavelength lasers utilizing different emission peaks of the Nd:GdVO4 were realized. The third wavelength was achieved through an additional Nd:YAG and VBG inside the laser cavity.
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Dennis, Ryan Shaun. "Development of a localized heat treatment tool for shape memory alloy wires using an Ytterbium fiber laser." 2005. http://www.lib.ncsu.edu/theses/available/etd-05252005-121400/unrestricted/etd.pdf.
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Kim, Chong Su. "Democracy as romance and satire: democratisation in South Korea by social movements." Thesis, 2011. http://hdl.handle.net/1828/3504.
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This thesis investigates democratisation in South Korea. Unlike what structure- and process-oriented accounts of democratisation claim, democracy in South Korea was achieved through sustained popular action. The late-late development led by the authoritarian developmental state did not allow bourgeois or institutional politics to take the leading role for democracy. Social movements replaced them by making political opportunities and developing collective identity, their mobilising structures, and by using various discourses, repertoires, and framing. The structural context, movements' interaction with the state, and their strategies produced democracy with paradoxical results. Not only did they fail to achieve social democracy as their objective, but also the “founding election” for the transition to democracy in 1987 was exploited by elites. The paradoxical process of democratisation suppressed the reverse transition to reauthoritarianism on the one hand and constrained the popular sovereignty expressed through constitutionally legitimate massive collective action on the other hand. Though democratisation through collective action did not end “happily ever after,” it brought about democracy not only in institutional politics but also in noninstitutional politics.Graduate
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Brannan, Kelly Elizabeth. "The effect of early incubation temperature and late incubation conditions on embryonic development and subsequent broiler performance." 2007. http://www.lib.ncsu.edu/theses/available/etd-11062007-110540/unrestricted/etd.doc.pdf.
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Ke, Yi-Ting, and 柯懿婷. "Characterization of rice group 3 late embryogenesis abundant (LEA) genes expression during development stages and stresses." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/19841679547631104410.
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碩士國立中央大學
生物資訊與系統生物研究所
97
Late embryogenesis abundant (LEA) proteins were initially found in the stage of embryo maturation. According to amino acid sequence similarities and conserved motifs, the LEA proteins can be separated into more than five groups. It is known that abscisic acid (ABA), salt, drought or cold stress can induce expression of the lea genes, conferring stress tolerance to plant cells. LEA proteins have been shown to involve in binding and replacement of water molecule, ion sequestration, maintaining of protein or cell membrane structure, and development regulation. Group 3 LEA proteins are characterized by 11-mer amino acid conserved tandem repeats (TEAAKQKAAET) and considered as the stress proteins. Barley HVA1, a member of group 3 LEA proteins, has been reported that it can improve stress tolerance in transgenic plants. However, its exact physiological functions still remain unclear. In this study we used the sequence BLAST to search Group 3 LEA protein orthologues in rice genome database and identify five lea3-like genes. They are AP004018/BAD19162, AP003381/BAB86507, AC073556/AAL84288, AC098833/AAU43988, AP000836/BAD81113 (gene/protein accession number). Here we were trying to characterize their gene sequence organization and expression patterns during developmental stages and environmental stresses. The results showed that these LEA genes played important roles on regulation of plant growth and response for varied stresses, and tissue-specific expression in root, stem, leaf, and seed. Furthermore, cellular localization analysis of the AP004018-GFP, AP003381-GFP, AC073556-GFP, AC098833-GFP, and AP000836-GFP fusion proteins in onion epidermal cells indicated that rice group 3 LEA proteins could be in nucleus (AP003381, AC073556 under ABA or 4℃ treatment), cytoplasm (AC073556, AC098833 under ABA; AP004018, AC073556, AC098833 under NaCl; AP004018, AC098833 under 4℃ treatment), or membrane structure (AC073556 under ABA and NaCl; AP004018, AP003381, AC073556, and AC098833 under 4℃ treatment ), whereas these fusion proteins localize in either nucleus or cytoplasm under non-stress conditions.
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Chen, I.-Cheng, and 陳乙誠. "Development of a Simple Laser Measurement System for The Four-Degree-of-Freedom Geometric Errors Measurement of a Linear Stage." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/09678151406673939196.
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碩士國立臺灣科技大學
機械工程系
103
This study aims to develop a simple 4-degree-of-freedom (DOF) automatic optical measuring system which is capable of measuring the horizontal/vertical straightness error and pitch/yaw angular error of a linear stage. The developed measuring system consists of 4 main modules, namely, the motion mechanism module, the optical path unit module, the electrical signal processing and control module and a set of software to integrate the measuring system and to execute the measurement analysis. Based on the user-input measurement parameters, this system can detect the desired straightness and angular deviation simultaneously. Our experimental optical path includes laser diode, beam expander, mirror, focusing lens, beamsplitter and location sensor (DL-10, DL-20). Following the principle of automatic alignment collimator, we can deflect a plane mirror and make laser resource to focus on the location sensor DL-20. Because of the deflection, the laser spot will have change in movement and get the angle difference received by location sensor DL-10. And then, based on the beam-split technique, our system can work on using the same light resource to measure the straightness, for using laser straight-line method to measure the straightness by DL-10. In order to verify the feasibility and performance of our system, we apply a single-axis precise positioning table in several experiments, and compared the result with the counterparts generated by LDDM. The result prove that the horizontal and vertical straightness is and , and the yaw and pitch angular error is less than and , respectively. During 5 minutes operating time, the movement and angle stability is ±0.6μm and ±1 arc⁄sec.
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Schaffers, Kathleen I. "A study of new optical materials I. Crystal-chemical development of new optical frequency converters II. New hosts for Cr3+ luminescence and lasing." Thesis, 1992. http://hdl.handle.net/1957/32543.
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The emphasis of this work has been in two areas of optical materials - the
crystal-chemical development of new optical frequency converters and the synthesis
and study of new hosts for Cr����� luminescence and lasing.
A simple method has been developed to identify promising frequency-doubling
materials containing triangular oxoanions by estimation of nonlinear
susceptibilities. Implementation of this method and its results have generated
predictive capabilities in determining the relationships among crystal structure,
nonlinear properties, and threshold powers. The new noncentrosymmetric borate
SrLiB���O������ is discussed; its structure is built from a 3-dimensional condensation of
B���0��� units with channels alternately filled with Sr and Li atoms. From these
studies, a prescription for new pyroborate frequency converters has been
developed. The material CdC������C���H7NO���, has been synthesized and structurally
characterized by single-ciystal X-ray diffraction.
Three new alkaline-earth beryllium borates, built from unique 2- and 3-
dimensional networks and frameworks, have been identified. The structure of
SrBe���(B0���)��� consists of layers of composition [Be���(BO���)���] interleaved by Sr atoms.
CaBeB���O��� is constructed from a Ca0��� polyhedral network and a beryllium borate
network. In BaBe���(B0���)��� the structure is composed of a beryllium borate
framework intermingled with a Ba-centered dodecahedral framework.
Several materials with potential as hosts for Cr����� lasing have been analyzed.
The structural study of the laser host LiSrAIF6 revealed the distortions at the Al
site that contribute to the unique optical properties of the Cr����� -doped crystals.
The family of solid state oxide A���MM'(B0���)��� is one of the largest families of oxide
reported to date. Metal site preferences, disorder, solid solubility, and the
interrelationship between this structure and the layered structure type of
Ba���Sc(B0���)��� are detailed. An optimal synthetic procedure has been developed for
these materials to provide pure, highly crystalline phases. Also, the structural and
optical features of (Cr�����:) Sr���In(B0���)��� with A= Sr and M=M'= In have been
studied.
The material Sr���LilnB���O������, was discovered while searching for a suitable
lithium borate flux for crystal growth of the compound Sr���In(B0���)���.Graduation date: 1993
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Berro, Adam Joseph. "Catalysis and materials development in organic chemistry." Thesis, 2009. http://hdl.handle.net/2152/ETD-UT-2009-08-269.
Full textAbstract:
The field of organic chemistry is divided into many subfields, which include polymer design and synthesis, transition metal catalysis and organocatalysis among a variety of others. Challenges in polymer design and synthesis can be highlighted pointedly in the use of photoresists for lithographic processing. Recent challenges in development of shorter wavelength sources has led to the need to develop new photoresist materials that can be exposed twice without any development steps in between. Two methods for addressing double exposure materials will be presented. Additionally, the areas of catalysis, whether transition metal or organic in nature, are important methods in organic synthesis. The mechanism of the addition of Gilman reagents to enones has been the subject of debate, and efforts to elucidate this mechanism will be presented. Finally, organocatalysis has expanded its scope into a variety of reactions previously only conducted with transition metal catalysts. Work towards an enantioselective allylic amination reaction using organocatalysis as well as absolute stereochemistry of the product will be explored.text
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Sampson, Jason Scott. "Development and characterization of an atmospheric pressure ionization source matrix-assisted laser desorption electrospray ionization coupled to fourier transform ion cyclotron resonance mass spectrometry for analysis of biological macromolecules." 2009. http://www.lib.ncsu.edu/theses/available/etd-07082009-135719/unrestricted/etd.pdf.
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Gu, Xinyu. "Design and development of material-based resolution enhancement techniques for optical lithography." 2011. http://hdl.handle.net/2152/22248.
Full textAbstract:
The relentless commercial drive for smaller, faster, and cheaper semi-conductor devices has pushed the existing patterning technologies to their limits. Photolithography, one of the crucial processes that determine the feature size in a microchip, is currently facing this challenge. The immaturity of next generation lithography (NGL) technology, particularly EUV, forces the semiconductor industry to explore new processing technologies that can extend the use of the existing lithographic method (i.e. ArF lithography) to enable production beyond the 32 nm node. Two new resolution enhancement techniques, double exposure lithography (DEL) and pitch division lithography (PDL), were proposed that could extend the resolution capability of the current lithography tools. This thesis describes the material and process development for these two techniques. DEL technique requires two exposure passes in a single lithographic cycle. The first exposure is performed with a mask that has a relaxed pitch, and the mask is then shifted by half pitch and re-used for the second exposure. The resolution of the resulting pattern on the wafer is doubled with respect to the features on the mask. This technique can be enabled with a type of material that functions as optical threshold layer (OTL). The key requirements for materials to be useful for OTL are a photoinduced isothermal phase transition and permeance modulation with reverse capabilities. A number of materials were designed and tested based on long alkyl side chain crystalline polymers that bear azobenzene pendant groups on the main chain. The target copolymers were synthesized and fully characterized. A proof-of-concept for the OTL design was successfully demonstrated with a series of customized analytical techniques. PDL technique doubles the line density of a grating mask with only a single exposure and is fully compatible with current lithography tools. Thus, this technique is capable of extending the resolution limit of the current ArF lithography without increasing the cost-of-ownership. Pitch division with a single exposure is accomplished by a dual-tone photoresist. This thesis presents a novel method to enable a dual-tone behavior by addition of a photobase generator (PBG) into a conventional resist formulation. The PBG was optimized to function as an exposure-dependent base quencher, which mainly neutralizes the acid generated in high dose regions but has only a minor influence in low dose regions. The resulting acid concentration profile is a parabola-like function of exposure dose, and only the medium exposure dose produces a sufficient amount of acid to switch the resist solubility. This acid response is exploited to produce pitch division patterns by creating a set of negative-tone lines in the overexposed regions in addition to the conventional positive-tone lines. A number of PBGs were synthesized and characterized, and their decomposition rate constants were studied using various techniques. Simulations were carried out to assess the feasibility of pitch division lithography. It was concluded that pitch division lithography is advantageous when the process aggressiveness factor k₁ is below 0.27. Finally, lithography evaluations of these dual-tone resists demonstrated a proof-of-concept for pitch division lithography with 45 nm pitch divided line and space patterns for a k₁ of 0.13.text
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Petrova-Mayor, Anna [Verfasser]. "Development of an eye-safe solid-state tunable laser transmitter around 1.45 μm [my-m] based on Cr4+:YAG crystal for lidar applications / vorgelegt von Anna Petrova-Mayor." 2008. http://d-nb.info/989330982/34.
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Banerjee, Anjan. "Design, Development and Applications R & D on Substrate-Integrated Lead-Carbon Hybrid Ultracapacitors." Thesis, 2014. http://etd.iisc.ernet.in/2005/3477.
Full textAbstract:
Electrochemical capacitors or supercapacitors or ultracapacitors are potential energy storage devices that could help bringing major advances in future energy storage applications. Unlike batteries that store energy in chemical reactants capable of generating charge, electrochemical capacitors store energy directly through charge separation. Most electrochemical capacitors rely on carbon-based structures utilizing electrical double-layer capacitance effect. By contrast, a pseudocapacitor relies on charge stored due to fast faradaic charge-transfer processes with surface atoms. A combination of faradaic and non-faradaic components would generate hybrid electrochemical capacitors or hybrid ultracapacitors that attain high capacitance for pulse power and sustained energy. This thesis comprises studies pertaining to design, development and applications R&D on substrate-integrated lead-carbon hybrid ultracapacitors.
The thesis comprises ten chapters. Chapter 1 is a brief introduction on essentials of electrochemical capacitors explaining their operating principles, classification and applications.
Chapter 2 describes studies on materials for electrical double-layer capacitors. Activated carbons are the most common materials for electrical double-layer capacitors. Various activated carbon samples are screened as suitable materials for electrical double-layer capacitor followed by their optimization under varying experimental conditions to form the negative plate in the substrate-integrated lead-carbon hybrid ultracapacitor.
Chapter 3 deals with the studies on design and development of 2 V substrate-integrated lead-carbon hybrid ultracapacitors with flooded, absorbent-glass-mat and silica-gel sulfuric acid electrolyte configurations. Lead-carbon hybrid ultracapacitors comprise substrate-integrated lead dioxide sheets as positive plates and high surface-area-carbon-coated graphite-sheets as negative plates. Operating principle for 2 V lead-carbon hybrid ultracapacitors is explained and optimization of their operating conditions along with their electrochemical performance is studied.
Chapter 4 is a study on the integration of 2 V substrate-integrated lead-carbon hybrid ultracapacitors to 12 V devices. 12 V substrate-integrated lead-carbon hybrid ultracapacitors with flooded, absorbent-glass-mat and silica gel sulfuric acid electrolyte are developed by connecting six 2 V cells in series. These hybrid ultracapacitors exhibit high power-density values and excellent cycle-life. The problem of uneven performance among the six 2 V cells in the 12 V hybrid ultracapacitors is addressed and resolved by applying voltage-management cell-balancing circuitry.
Chapter 5 details the studies on kilo-Farad range 12 V substrate-integrated lead-carbon hybrid ultracapacitors. The hybrid ultracapacitors are performance tested through a standard protocol. Thermal runaway in these hybrid ultracapacitors at high load currents is studied by thermal imaging.
Studies on performance comparison between 12 V lead-carbon hybrid ultracapacitors with substrate-integrated and conventional pasted-positive plates are presented in Chapter 6. For substrate-integrated-positive plate lead-carbon hybrid ultracapacitors, capacitance and energy-density values are lower but power-density values are higher than pasted-positive plate configuration due to their shorter response-time. Accordingly, internal resistance values are lower for substrate-integrated lead-carbon hybrid ultracapacitors. Both types of lead-carbon hybrid ultracapacitors exhibit similar faradaic efficiency and cycle-life in excess of 100,000 pulse charge/discharge cycles with only a nominal loss in their capacitance values.
Chapter 7 is a study on the design and development of low-cost substrate-integrated lead-carbon hybrid ultracapacitors using poly-aniline organic metal. The hybrid ultracapacitor employs flexible exfoliated graphite sheets as negative plate current-collectors, which are coated with a thin layer of poly-aniline to provide good adhesivity to activated carbon layer and good substrate-conductivity. These ultracapacitors are estimated to cost about 4 US$/Wh as compared to 20-30 US$/Wh for presently available commercial ultracapacitors.
In Chapter 8, an application R&D study on the suitability of a substrate-integrated lead-carbon hybrid ultracapacitor bank in powering medical gadgets is described. A practical application that provides 30 W power back-up to medical gadgets for use in grid-power-deficient rural areas is presented.
Chapter 9 is another application R&D study in realizing a photovoltaic stand-alone lighting system using substrate-integrated lead-carbon hybrid ultracapacitors. At present, harnessing solar electricity generated through photovoltaic cells with lead-acid batteries remains the most compelling option. But lead-acid batteries have encountered problems in photovoltaic installations, mainly due to their premature failure. To circumvent this problem, substrate-integrated lead-carbon hybrid ultracapacitors are developed for solar energy storage for a lighting application.
The last Chapter of the thesis comprises field studies on substrate-integrated lead-carbon hybrid ultracapacitors. In the study, hybrid ultracapacitors are installed for lighting applications for field tests. Grid-power chargers and mechanical dynamos are introduced as fast-charging tools for hybrid ultracapacitors.
It is hoped that the studies presented in this thesis would constitute a worthwhile contribution to science and technology of electrochemical capacitors. Considering the technology need, availability, safety and cost, substrate-integrated lead-carbon hybrid ultracapacitors are set to play a seminal role in future energy storage and management.
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Cook, Suzanne L. "Redirection: Using Career Development Theory to Interpret the Volunteer Activities of Retirees." Thesis, 2010. http://hdl.handle.net/1807/29690.
Full textAbstract:
The purpose of this study was to examine formal volunteering among retirees in order to explore whether their volunteer experiences represent an extension of their career in the paid workforce or whether their volunteer activities represent a completely new direction, and how this influences their career self-concept, as interpreted through Donald Super’s life-span, life-space theory of career development. This study employed a developmental mixed-method design. In Phase 1, qualitative interviews were conducted with 12 participants to better understand retirees’ volunteer experiences. Phase 1 informed the design of an instrument for the Phase 2 survey which examined the issues among a larger sample of 214 retirees. The Phase 2 results supported the Phase 1 findings and indicated that many retirees sought an extension of career in volunteer activities in that they used similar skills and knowledge. Study participants also displayed a desire for lifelong learning.
Retirees relinquished their paid-work career, took on the retiree and volunteer roles, and integrated these roles within their career self-concept to create a new sense of self. These results indicated that the retirees had entered a new stage of life, qualitatively different from ‘retirement’. To better reflect the experiences of these retirees, it was proposed that Donald Super’s life-span, life-space theory of career development be extended to include Redirection. This theorizing is consistent with the finding that retirees both wanted to and are able to integrate previous paid work elements as well as seek out lifelong learning opportunities within their volunteer activities. This study demonstrates that the volunteer role in the lives of retirees can lead to personal renewal and reshaping of the career self-concept, or what is labeled as the stage of Redirection. This study also has implications for volunteer management, retirement planning and social policy, and may be of interest to volunteer managers, nonprofit organizations, career counsellors, financial planners, retirement planning consultants, life coaches and policy planners.