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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Identification of Vanadium-Binding Ligands in White Wine

Trybom, Freja T January 2023 (has links)
Vanadin är en värdefull metall och kan lakas ur LD (Linz-Donawitz)-slagg med hjälp av vin. Ligander i vinet som lakar vanadin från LD-slagg studerades i denna rapport med mål att identifiera några av deras egenskaper såsom apparent molekylmassa och spektral information. Hyfenerad analys med hjälp av högupplösande vätskekromatografi-mikrovågsplasma med atomemissionspektrometer (HPLC-MP-AES) gjordes för att matcha vanadintoppen från vinet med ett apparent masspann från en gelfiltreringskolonn. Spektral analys visade att det fanns tre misstänkta vanadinligander i det analyserade vinet. Apparent molekylmassa hos liganderna var sannolikt inom spannet 24 Da – 570 Da. / Vanadium is a valuable metal and can be extracted from Linz-Donawitz (LD) converter slag using wine. Ligands in wine responsible for leaching vanadium from LD converter slag were studied in this report in an effort to identify some of their properties such as apparent molecular mass and spectral information. Hyphenated analysis using high performance liquid chromatography-microwave plasma atomic emission spectroscopy (HPLC-MP-AES) was performed to match a vanadium peak from the wine with an apparent mass span from a size exclusion chromatography (SEC) column. Spectral analysis of the vanadium peak revealed that there were three compounds suspected to be ligands to vanadium in the wine analyzed. Apparent molecular mass of the ligands wasfound to likely be between 24 Da - 570 Da.
52

Optimization of GAN Laser Diodes Using 1D and 2D Optical Simulations

Jobe, Sean Richard Keali'i 01 March 2009 (has links) (PDF)
This paper studies the optical properties of a GaN Laser Diode (LD). Through simulation, the GaN LD is optimized for the best optical confinement factor. It is found that there are optimal thicknesses of each layer in the diode that yield the highest optical confinement factor. There is a strong relationship between the optical confinement factor and lasing threshold—a higher optical confinement factor results in a lower lasing threshold. Increasing optical confinement improves lasing efficiency. Blue LDs are important to the future of lighting sources as they represent the final color in the RGB spectrum that does not have a high efficiency solution. The modeled GaN LD emits blue light at around ~450nm. Each layer of the GaN LD is drawn in a model simulation program called LaserMOD created by RSOFT Design Group, Inc. By properly modifying the properties of each layer, an accurate model of the GaN LD is created and then simulated. This paper describes the steps taken to properly model and optimize the GaN LD in the 1D and 2D models.
53

Monolithic integration of III-V optoelectronics on SI

Kwon, Ojin 24 August 2005 (has links)
No description available.
54

Scale effects on genomic modelling and prediction

Berger, Swetlana 03 February 2015 (has links)
In dieser Arbeit wird eine neue Methode für den skalenunabhängigen Vergleich von LD-Strukturen in unterschiedlichen genomischen Regionen vorgeschlagen. Verschiedene Aspekte durch Skalen verursachter Probleme – von der Präzision der Schätzung der Marke-reffekte bis zur Genauigkeit der Vorhersage für neue Individuen - wurden untersucht. Darüber hinaus, basierend auf den Leistungsvergleichen von unterschiedlichen statistischen Methoden, wurden Empfehlungen für die Verwendungen der untersuchten Methoden gege-ben. / In dieser Arbeit wird eine neue Methode für den skalenunabhängigen Vergleich von LD-Strukturen in unterschiedlichen genomischen Regionen vorgeschlagen. Verschiedene Aspekte durch Skalen verursachter Probleme – von der Präzision der Schätzung der Marke-reffekte bis zur Genauigkeit der Vorhersage für neue Individuen - wurden untersucht. Darüber hinaus, basierend auf den Leistungsvergleichen von unterschiedlichen statistischen Methoden, wurden Empfehlungen für die Verwendungen der untersuchten Methoden gegeben
55

Pharmacochimie radicalaire à visée antirhinovirale / Pharmacochemistry for the synthesis of new antirhinoviruses

Roche, Manon 18 December 2013 (has links)
Ce travail de pharmacochimie est consacré à la synthèse de nouvelles molécules benzéniques en vue d’étudier leurs propriétés pharmacologiques in vitro sur le Rhinovirus humain 14 mais également d’en déduire des relations de structure activité. En effet, le fil conducteur du projet de thèse est un travail de pharmacomodulation en collaboration avec le Rega Institute for Medical Research de Louvain. La méthode principale de synthèse de ces structures est basée sur la méthodologie TDAE ou Tétrakis(DiméthylAmino)Ethylène, appliquée sur des substrats dérivés du chlorure de nitrobenzyle. La synthèse et l’évaluation biologique de plus de 100 molécules a permis de décrire 5 hits dérivés du 4,5-diméthoxybenzène présentant des activités biologiques intéressantes in vitro (Concentration Effective Médiane de 1,5 à 4,3 μM ; index de sélectivité de 6 à 92). Les différentes stratégies adoptées lors de ce travail de pharmacochimie ont permis d’étendre l’étude des réactions par transfert monoélectronique sur de nouveaux substrats. Ainsi, le 1-(3-chloroprop-1-ynyl)-4-nitrobenzène a fait l’objet d’une étude en méthodologie LD-SRN1 avec des nitroalcanes, nitrocycloalcanes ainsi qu’avec des anions sulfinates ; ces travaux ont permis de décrire de nouveaux substrats insaturés originaux avec de bons rendements. De plus, la réactivité de ce substrat original a été évaluée en méthodologie TDAE avec des aldéhydes aromatiques. Ces travaux ont été valorisés par la synthèse de diarylbutynols originaux et ouvrent de nombreuses perspectives de recherche sur ce même noyau. / This pharmacochemistry work aims at synthesizing of new benzenic derivatives molecules with the scope to study both the chemical and antirhinoviruses 14 pharmacological properties in vitro. In fact, this work was focused on the pharmacomodulation of benzonitrile derivatives in collaboration with Rega Institute for Medical Research group. One hundred structural analogues were synthesized and a structure-activity-relationship was established. Biological assays showed five molecules with interesting anti-hRV 14 activities (EC50 from 1.5 to 4.3 and selectivity index from 6 to 92).These products derived from the TDAE-initiated reaction of various nitrobenzyl chloride analogues. Different strategies directed toward this pharmacochemistry project permitted to study single electron transfer (SET) reaction on original substrates. In this way, we explored the concept of LD-SRN1 on a propargylic chloride derivative such as 1-(3-chloroprop-1-ynyl)-4-nitrobenzene with nitronate and sulfinate anions. This latter compound also constitutes a potential substrate for the preparation of a propargylic anion using the TDAE strategy. So, we examined the use of TDAE methodology in alkyne series with various aromatic aldehydes in the presence of TDAE. These last works opened the scope of single electron transfer (SET) reactions.
56

Optimisation des méthodes statistiques d'analyse de la variabilité des caractères à l'aide d'informations génomiques / Optimization of statistical methods using genomic data for QTL detection

Jacquin, Laval 10 October 2014 (has links)
L’avènement du génotypage à haut débit permet aujourd’hui de mieux exploiter le phénomène d’association, appelé déséquilibre de liaison (LD), qui existe entre les allèles de différents loci sur le génome. Dans ce contexte, l’utilité de certains modèles utilisés en cartographie de locus à effets quantitatifs (QTL) est remise en question. Les objectifs de ce travail étaient de discriminer entre des modèles utilisés en routine en cartographie et d’apporter des éclaircissements sur la meilleure façon d’exploiter le LD, par l’utilisation d’haplotypes, afin d’optimiser les modèles basés sur ce concept. On montre que les modèles uni-marqueur de liaison, développés en génétique il y a vingtaine d’années, comportent peu d’intérêts aujourd’hui avec le génotypage à haut débit. Dans ce contexte, on montre que les modèles uni-marqueur d’association comportent plus d’avantages que les modèles uni-marqueur de liaison, surtout pour des QTL ayant un effet petit ou modéré sur le phénotype, à condition de bien maîtriser la structure génétique entre individus. Les puissances et les robustesses statistiques de ces modèles ont été étudiées, à la fois sur le plan théorique et par simulations, afin de valider les résultats obtenus pour la comparaison de l’association avec la liaison. Toutefois, les modèles uni-marqueur ne sont pas aussi efficaces que les modèles utilisant des haplotypes dans la prise en compte du LD pour une cartographie fine de QTL. Des propriétés mathématiques reliées à la cartographie de QTL par l’exploitation du LD multiallélique capté par les modèles haplotypiques ont été explicitées et étudiées à l’aide d’une distance matricielle définie entre deux positions sur le génome. Cette distance a été exprimée algébriquement comme une fonction des coefficients du LD multiallélique. Les propriétés mathématiques liées à cette fonction montrent qu’il est difficile de bien exploiter le LD multiallélique, pour un génotypage à haut débit, si l’on ne tient pas compte uniquement de la similarité totale entre des haplotypes. Des études sur données réelles et simulées ont illustré ces propriétés et montrent une corrélation supérieure à 0.9 entre une statistique basée sur la distance matricielle et des résultats de cartographie. Cette forte corrélation a donné lieu à la proposition d’une méthode, basée sur la distance matricielle, qui aide à discriminer entre les modèles utilisés en cartographie. / The advent of high-throughput genotyping nowadays allows better exploitation of the association phenomenon, called linkage disequilibrium (LD), between alleles of different loci on the genome. In this context, the usefulness of some models to fine map quantitative trait locus (QTL) is questioned. The aims of this work were to discriminate between models routinely used for QTL mapping and to provide enlightenment on the best way to exploit LD, when using haplotypes, in order to optimize haplotype-based models. We show that single-marker linkage models, developed twenty years ago, have little interest today with the advent of high-throughput genotyping. In this context, we show that single-marker association models are more advantageous than single-marker linkage models, especially for QTL with a small or moderate effect on the phenotype. The statistical powers and robustness of these models have been studied both theoretically and by simulations, in order to validate the comparison of single-marker association models with single-marker linkage models. However, single-marker models are less efficient than haplotype-based models for making better use of LD in fine mapping of QTL. Mathematical properties related to the multiallelic LD captured by haplotype-based models have been shown, and studied, by the use of a matrix distance defined between two loci on the genome. This distance has been expressed algebraically as a function of the multiallelic LD coefficients. The mathematical properties related to this function show that it is difficult to exploit well multiallelic LD, for a high-throughput genotyping, if one takes into account the partial and total similarity between haplotypes instead of the total similarity only. Studies on real and simulated data illustrate these properties and show a correlation above 0.9 between a statistic based on the matrix distance and mapping results. Hence a new method, based on the matrix distance, which helps to discriminate between models used for mapping is proposed.
57

Påverkan av sena tillsatser på medföljande slagg och dess viskositet i LD-processen

Forsberg, Oscar January 2020 (has links)
Vid SSAB Europé i Luleå produceras höghållfaststål. För att uppnå sådan kvalité måste renligheten i stålet vara god i hela processen. Risken att få förhöjda värden av exempelvis vanadin efter LD-processen vid deoxidationssteget, då medföljande vanadininhållande slagg som återreduceras till stålet är hög. Det finns olika system som jobbar för att förhindra medföljande slagg vid tappning av LD-konvertern. På SSAB i Luleå används IR-kamera för att identifiera slagg vid tappning och en mekanisk slaggstoppare som blockerar tapphålet samt tvingar flödet tillbaka in i konvertern med hjälp av kvävgas. Ett annat möjligt system att använda skulle kunna vara slaggens viskositet, då en högviskös slagg skulle fungera som en vortexinhibitor och därigenom reducera mängden medföljande slagg. Målet med examensarbetet har varit att undersöka sena tillsatsers påverkan av medföljande slagg, där de sena tillsatserna syftar till att öka viskositeten på slaggen genom att skapa fasta partiklar. I daglig drift görs ingen uppskattning av mängden medföljande slagg eller hur sena slaggtillsatser påverkar detta. Genom slaggprovtagning samt stålprover innan och efter tappning av LD-konvertern kan en massbalans göras av mängden medföljande slagg. Beräkningsämnena som passade bäst i denna studie var kisel och vanadin, två ämnen som oftast återfinns endast i slaggen. Utifrån resultatet av proverna visade sena tillsatser inte ha någon påverkan av mängden medföljande slagg. Ingen påvisad skillnad av viskositetsberäkningarna kunde kopplas till de sena tillsatserna, där beräkningarna gjordes i FactSage. Studien visade att sena tillsatser inte har den önskade effekten på medföljande slagg som man tidigare trott och skulle kunna tas bort helt. Detta för att reducera kostnaderna för tillsatser och deponi. Slaggen fick flytegenskaper redan vid 72% andel fasta partiklar och en temperatur på 1379°C. Vid LD-processen har slaggen 8% andel fasta partiklar och temperatur på 1739°C. Detta påvisar att det blir praktiskt omöjligt att styva upp slaggen i LD-processen med hjälp av sena tillsatser. / SSAB Europé in Luleå produce high-strength steel. To reach this quality the purity must be good in the whole process. There is a risk to get a high value of for example vanadium in the steel after the LD-process at the deoxidations step. The carried-over slag from the LD-process has a high content of vanadium that may reduce back to the steel from the deoxidation agent.  Several process systems work to reduce the amount of carried-over slag at LD-converter. At SSAB in Luleå this system is an IR-camera that is used for detecting carried-over slag at the tapping of the converter and a mechanical slagblocker that block the tapping jet and blow back the slag using nitrogen.  Another possible system could be to use the slag viscosity. High viscous slag will work like a vortex inhibitor and reduce the amount of carried-over slag. The goal of this master thesis is to study late additives impact of the amount of carried-over slag, there the purpose of the late additives is to increase the viscosity of the slag through solve in solid particles.  In the daily operations SSAB doesn´t do an estimate of the amount of carried-over slag or how the late additives affect carried-over slag. By conducting slag and steel sampling before and after tapping the LD-converter a mass balance can be used to calculate the amount of carried-over slag. The base of the mass calculation that fit beast in this study was silicon and vanadium. Two substances that often occurs in the slag. From the results of the samples, the late additive didn´t do any impact on the amount of carried-over slag. No impact of the viscosity calculation could connect to the amount of carried-over slag. The calculation has been done in FactSage. The study shows that late additive don´t have any impact on the amount of carried-over slag and that is why it should be avoided. This could decrease the cost of additive and landfill. The slag gets flow properties as early as 72% share solid particles and temperature at 1379°C and in the LD-process the slag had 8% share solid particles and temperature at 1739°C. This shows that it´s practically impossible to stiff up the slag in the LD-process with help of late additive.
58

NONCOHERENT AND DIFFERENTIAL DETECTION OF FQPSK WITH MAXIMUM-LIKELIHOOD SEQUENCE ESTIMATION IN NONLINEAR CHANNELS

Lin, Jin-Son, Feher, Kamilo 10 1900 (has links)
International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / This paper presents noncoherent limiter-discriminator detection and differential detection of FQPSK (Feher quadrature phase-shift-keying) with maximum-likelihood sequence estimation (MLSE) techniques. Noncoherent FQPSK systems are suitable for fast fading and cochannel interference channels and channels with strong phase noise, and they can offer faster synchronization and reduce outage events compared with conventional coherent systems. In this paper, both differential detection and limiter-discriminator detection of FQPSK are discussed. We use MLSE with lookup tables to exploit the memory in noncoherently detected FQPSK signals and thus significantly improve the bit error rate (BER) performance in an additive white Gaussian noise (AWGN) channel.
59

Levantamento das inclusões nos principais grupos de aços produzidos em aciaria do tipo LD. / Non-metallic inclusions in BOF steels, secondarily refined, destined to continuous casting of slabs.

Faco, Rubens José 14 March 2006 (has links)
Foram tomadas amostras de aço líquido referentes a três grupos de aço, a saber: (I) aços baixo-carbono (0,02 %C 0,08), acalmados ao alumínio; (II) aços peritéticos (0,09 %C 0,15), acalmados ao alumínio e silício; (III) aços ultrabaixo carbono ( C<35 ppm), acalmados ao alumínio.Os aços foram produzidos em aciaria do tipo LD e foram, a seguir, tratados em equipamentos de refino secundário, adequados a cada um dos casos.As amostras forma colhidas no distribuidor de uma máquina de lingotamento contínuo de placas, segundo critério que minimiza a possibilidade da ocorrência de interferências que pudessem mascarar o resultado do tratamento de refino secundário tais como re-oxidação do aço e coleta simultânea de escória. As amostras foram submetidas à análise de inclusões utilizando-se técnicas de microscopia óptica, microscopia eletrônica e micro-análise. Foi possível caracterizar as inclusões presentes em cada tipo de aço segundo a morfologia, o tamanho, a quantidade e a composição química. / Non-metallic inclusions in liquid samples of (I) low-carbon aluminium killed steel (0,02wpct C 0,08wpct), (II) peritetic aluminium and silicon killed steel (0,09wpct C 0,15wpct); (III) extra-low-carbon, aluminium killed steel (C<35 ppm) were taken from the tundish distributor of a continuous casting caster for steel plates according to a procedure that minimizes re-oxidation of steel and/or pick up of liquid slag. The samples were inspected through the following microstructural techniques: optical microscopy, electronic microscopy, and electron microprobe. Were possible to feature present inclusion in each kind of steel according to morphology, size, amout and chemical composition.
60

Ultra-Wideband Transceiver with Error Correction for Cortical Interfaces in NanometerCMOS Process

Luo, Yi 01 May 2017 (has links)
This dissertation reports a high-speed wideband wireless transmission solution for the tight power constraints of cortical interface application. The proposed system deploysImpulse Radio Ultra-wideband (IR-UWB) technique to achieve very high-rate communication. However, impulse radio signals suffer from significant attenuation within the body,and power limitations force the use of very low-power receiver circuits which introduce additional noise and jitter. Moreover, the coils’ self-resonance has to be suppressed to minimize the pulse distortion and inter-symbol interference, adding significant attenuation. To compensate these losses, an Error correction code (ECC) layer is added for functioning reliably to the system. The performance evaluation is made by modeling a pair of physically fabricated coils, and the results show that the ECC is essential to obtain the system’s reliability. Furthermore, the gm/ID methodology, which is based on the complete exploration ofall inversion regions that the transistors are biased, is studied and explored for optimizingthe system at the circuit-level. Specific focuses are on the RF blocks: the low noise am-plifier (LNA) and the injection-locked voltage controlled oscillator (IL-VCO). Through the analytical deduction of the circuit’s features as the function of the gm/ID for each transistor, it is possible to select the optimum operating region for the circuit to achieve the target specification. Other circuit blocks, including the phase shifter, frequency divider,mixer, etc. are also described and analyzed. The prototype is fabricated in a 65-nm CMOS(Complementary Metal-Oxide-Semiconductor) process.

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