Dissertations / Theses on the topic 'Emitter'
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1
Johnson, Eric (Eric M. ). "Self-installation of drip irrigation emitters for prototype emitter testing." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/105700.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.Cataloged from PDF version of thesis.
Includes bibliographical references (page 31).
In this thesis, I tested methods of adhering factory-made drip emitters to the interior of short segments of piping. Different types of adhesive and pipe material combinations were tested, and I selected three combinations for further testing. Performance similar to factory-installed drip emitters was achieved at low pressure, but the necessary watertight seals repeatedly burst at higher water pressures. Alterations to the drip emitter and installation procedure are recommended to increase reliability and resilience of the installation.
by Eric Johnson.
S.B.
2
Keyes, Edward Patrick Carleton University Dissertation Engineering Electrical. "Emitter resistance and current gain in polysilicon emitter transistors." Ottawa, 1987.
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3
Weynand, Vance Leo. "Evaluation of the application uniformity of subsurface drip distribution systems." Thesis, Texas A&M University, 2003. http://hdl.handle.net/1969.1/211.
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The goal of this research was to evaluate the application uniformity of subsurface drip distribution systems and the recovery of emitter flow rates. Emission volume in the field, and laboratory measured flow rates were determined for emitters from three locations. Additionally, the effects of lateral orientation with respect to slope on emitter plugging was evaluated. Two different emitters were tested to evaluate slope effects on emitter plugging (type Y and Z). The emitters were alternately spliced together and installed in an up and down orientation on slopes of 0, 1, 2 and 4% and along the contour on slopes of 1 and 2%. The emitters were covered with soil and underwent a simulated year of dosing cycles, and then flushed with a flushing velocity of 0.6 m/s. Initial flow rates for the two emitter types were 2.38 L/hr with a C.V. of 0.07. There was no significant difference in flow rates among slopes for type Y emitters, but there was a significant difference between the 1% and 2 % contour slopes for type Z emitters. Application uniformity of three different laterals at each site was evaluated. Sections of the lateral from the beginning, middle and end were excavated and emission volumes were recorded for each emitter. Application uniformity of laterals ranged from 48.69 to 9.49%, 83.55 to 72.60%, and 44.41 to 0% for sites A, B, and C, respectively. Mean emitter flow rate was 2.21, 2.24, and 2.56 L/hr for sites A, B, and C, respectively under laboratory conditions. Application uniformity under laboratory conditions ranged from 70.97 to 14.91%, 86.67 to 79.99%, and 85.04 to 0.00% for sites A, B, and C, respectively. A flushing velocity of 0.15 m/s with no chlorination, shock chlorination of 3400 mg/L and flushing velocity of 0.15 m/s, and shock chlorination of 3400 mg/L and flushing velocity of 0.6 m/s treatment regiments were applied to all laterals collected to assess emitter flow rate recovery to the nominal flow rate published by the manufacturer. All laterals showed an increase in the number of emitters within 10% of the published nominal flow rate.
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Mackay, Gary F. (Gary Francis) Carleton University Dissertation Engineering Electrical. "Emitter resistance and current gain in rapid thermal annealed polysilicon emitter transistors." Ottawa, 1991.
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5
Hartup, David Carl. "Emitter identification using optical processors." Diss., Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/15672.
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Constantinou, Marios, Michael Gehde, and Ronald Dietz. "Emitter - Material – A complex system." Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-198230.
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Der Vortrag zeigt die Komplexität der Wechselwirkungen zwischen Infrarotstrahler und Werkstoff beim Infrarotschweißen von Kunststoffen auf. Hierfür werden die Haupteinflüsse auf die Strahler-Werkstoff-Wechselwirkungen beschrieben. Diese sind das Emissionsverhalten des Infrarotstrahlers und das Absorptionsverhalten des Kunststoffs. Der Einfluss der Infrarotstrahlerart (Quarzglasstrahler, Metallfolienstrahler) und von Füllstoffen (Ruß, Glasfasern) im Kunststoff wird näher betrachtet. Zudem enthält der Vortrag eine Empfehlung für die Vorgehensweise beim Infrarotschweißen von Kunststoffen, die Vor- und Nachteile des Fügeverfahrens und einen Einblick in aktuelle Forschungsaktivitäten auf dem Gebiet des Infrarotschweißens von Kunststoffen.
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Post, Ian R. C. "PNP polysilicon emitter bipolar transistors." Thesis, University of Southampton, 1992. https://eprints.soton.ac.uk/394020/.
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Rowlandson, Michael Barry Carleton University Dissertation Engineering Electrical. "A true polysilicon emitter transistor." Ottawa, 1988.
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9
Aslan, Mehmet Kadir. "Emitter Identification Techniques In Electronic Warfare." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607675/index.pdf.
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In this study, emitter identification techniques have been investigated and a schema has been proposed to solve the emitter identification problem in Electronic Warfare systems.
Clustering technique, histogram based deinterleaving techniques and a continuous wavelet transform based deinterleaving technique have been reviewed. A receiver simulator software has been developed to test the performance of these techniques and to compare them against each other. To compensate the disadvantages of these techniques, a schema utilizing the beneficial points of them has been developed. With the modifications proposed a resultant schema has been obtained.
Proposed schema uses clustering and deinterleaving together with other proposed modifications. Tests made through out this study have shown that this usage improves performance of emitter identification system. Hence, proposed schema can be used to identify the emitters in real EW systems.
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Wolstenholme, G. R. "A study of polysilicon emitter transistors." Thesis, University of Southampton, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384186.
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Yang, Yujia S. M. Massachusetts Institute of Technology. "Development of optical field emitter arrays." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/84858.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2013.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 131-137).
Optical field emitters are electron emission sources actuated by incident light. Optically actuated field emitters may produce ultrafast pulses of electrons when excited by ultrafast optical pulses, thus making them of interest for specific applications such as ultrafast electron microscopy, diffraction and spectroscopy; and as electron sources for X-ray generation. Recently proposed intense, coherent, and compact X-ray sources require low emittance, high brightness and short duration electron bunches that form a periodic pattern in the transverse plane. This thesis theoretically developed optical field emitter arrays that are suitable for use as the electron source for this novel X-ray source. Studies of several optical field emitter array structures, including vertically-standing gold nanopillars and silicon tips, in-plane gold nanostructures, and metallic line gratings, were performed via theoretical analysis and numerical simulations. Enhancement of the optical nearfield and power absorption was achieved by geometrical and plasmonic effects, leading to enhanced charge yield from the optical field emitter arrays.
by Yujia Yang.
S.M.
12
Parker, Peter A., and Melina Lake. "Signal Emitter Localization Using Telemetry Assets." International Foundation for Telemetering, 2013. http://hdl.handle.net/10150/579671.
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ITC/USA 2013 Conference Proceedings / The Forty-Ninth Annual International Telemetering Conference and Technical Exhibition / October 21-24, 2013 / Bally's Hotel & Convention Center, Las Vegas, NVTelemetry ground stations spread over geographically diverse areas are well suited for use in passively locating the source of a distant transmitted signal. In a favorable positioning of receive sites, the accuracy of these passive localization techniques can compete with the accuracy of radars. In these cases, use of receive only assets is a less expensive alternative than the use of a radar's scarce resources. Until recently, the major technical challenge to implementation of the passive localization techniques of time-difference of arrival (TDOA) and frequency-difference of arrival (FDOA) has been the frequency and time stability of geographically separated receivers. Advances in GPS based timing and frequency references has made the implementation of TDOA and FDOA feasible. This paper shows how these limitations have been overcome using the current telemetry assets at the Reagan Test Site in Kwajalein Atoll.
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Schädler, Kevin Gerd. "Single quantum emitter manipulation with 2D materials." Doctoral thesis, Universitat Politècnica de Catalunya, 2018. http://hdl.handle.net/10803/586168.
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Photonics aims to manipulate light by controlling its interactions with matter to enable novel optical technologies for communication, information processing and sensing. Current efforts strive to enter the regime of quantum nanophotonics, where light interacts with nanoscale photonic elements at the single photon level. The realisation of such systems is challenging due to weak light-matter interaction at the nanoscale, which motivates the quest for new strategies and nanomaterials with enhanced interaction.
In this context, nanoscale solid state quantum light emitters which mimic the efficient interactions of trapped atoms with light are a key element for implementing quantum optical devices on chip.
The coupling of these quantum emitters to their nanoscale environment has two important consequences: i) controlling the environment enables control of the emitter, while conversely ii) the emitter acts as a nanoprobe of its environment. Therefore, hybrid systems which integrate such emitters with a controllable nano-environment enable manipulation of nanoscale quantum light.
Two-dimensional (2D) materials are a particularly promising platform for this purpose due to their unique blend of optoelectronic and mechanical properties which enable efficient, tuneable light-matter interactions and sensitive nanomechanical resonators with ultra-low mass and high mechanical resonance frequency.
In this thesis, I will introduce two different hybrid systems which integrate nanoscale quantum emitters with two-dimensional (2D) materials such as atomically thin graphene and MoS2.
I will first present a hybrid nano-optomechanical system which harnesses efficient near-field interactions to couple the nano-motion of a 2D mechanical graphene resonator to the emission strength of a quantum emitter (nitrogen vacancy centre, NVC) at a separation below 40 nm.
In this system, electromechanical control of graphene's nano-motion enables high-frequency (100 MHz) emission modulation, while conversely, the NVC acts as a transducer which enables optical readout of nano-motion in the photon counting regime.
In the second part of the thesis, I demonstrate that single molecules embedded in organic nanocrystals in a polymer display bright single photon emission with ultra-narrow linewidth close to the lifetime-limited value (~ 40 MHz). I show that these emitters can be integrated with 2D materials at sub-wavelength separation in a hybrid optoelectronic device without emission perturbation. Using the 2D materials as transparent electrodes, the device's nanoscale dimensions enable ultra-broadband tuning (tuning range > 400 GHz) and fast modulation (frequency ~ 100 MHz) of the emission energy, which renders it an integrated, ultra-compact tuneable single photon source.
These results demonstrate the potential of 2D materials for controlling quantum emitters and the use of an atomically small object to probe optoelectronic and mechanical properties of atomically thin materials.La fotónica tiene como objetivo la manipulación de la luz y el control de la misma cuando interactúa con la materia con el fin de desarrollar nuevas tecnologías ópticas con aplicaciones en diferentes campos, como son el de la comunicación, procesado de información y detección. En la actualidad, es de gran interés poder desarrollar este tipo de tecnología pero en el ámbito de la nanofotónica cuántica, donde la luz interactúa con elementos fotónicos de dimensión nanométrica mediante fotones únicos. La realización de este tipo de sistemas representa un importante desafío debido a la débil interacción que existe entre la luz y la materia a escala nanométrica, por lo que resulta imprescindible la búsqueda de nuevas estrategias y materiales en estas dimensiones que aumenten dicha interacción. En este contexto, los emisores de luz cuántica de estado sólido a escala nanométrica, que imitan las interacciones eficientes de los átomos atrapados con la luz, son un elemento clave para la implementación de dispositivos ópticos cuánticos en el chip. La implementación de estos emisores cuánticos en el entorno de la nanoescala conlleva dos efectos de gran importancia: i) el control del entorno permite controlar el emisor, mientras que al mismo tiempo ii) el emisor actúa como una sonda nanométrica del entorno. De este modo, los sistemas híbridos que integren dichos emisores en un entorno nano-controlable van a permitir la manipulación de la luz cuántica en la nanoescala. Los materiales bidimensionales (2D) son una plataforma particularmente prometedora para este propósito debido al conjunto de propiedades únicas que presentan, especialmente optoelectrónicas y mecánicas, que permiten interacciones eficientes de luz regulable y resonadores nanomecánicos sensibles con masa ultrabaja y alta frecuencia de resonancia mecánica. En esta tesis, se van a presentar dos sistemas híbridos diferentes que integran los emisores cuánticos a escala nanométrica, que incluyen materiales bidimensionales (2D) como son el grafeno y MoS2. En primer lugar, se demostrará la realización de un sistema nano-optomecánico híbrido que aprovecha las interacciones eficientes de campo cercano para acoplar el nano-movimiento de un resonador mecánico bidimensional de grafeno a la fuerza de emisión de un emisor cuántico (centro de vacío de nitrógeno, NVC) con una separación inferior a 40 nanómetros. En este sistema, el control electromecánico del nano-movimiento de grafeno permite la modulación de emisión de alta frecuencia (100 MHz), mientras que, a la inversa, el NVC actúa como un transductor que permite la lectura óptica de nano-movimiento en el régimen de conteo de fotones. En la segunda parte de la tesis, se demostrará que las moléculas individuales que han sido incrustadas en nanocristales orgánicos, y que a su vez se incluyen en un polímero, son una fuente brillante de fotones individuales con un ancho de línea muy estrecho y próximo a su tiempo de vida límite (40 MHz). También, se muestra que los emisores se pueden integrar en dispositivos optoelectrónicos híbridos utilizando materiales 2D con una separación inferior a una longitud de onda sin causar perturbación en la emisión. El uso de materiales 2D como electrodos transparentes en dispositivos de tamaño nanométrico permite la sintonización de banda ultra ancha (rango de sintonía > 400 GHz) y la modulación rápida (frecuencia ~ 100 MHz) de la energía de emisión. Por ello, estos dispositivos actúan como una fuente integrada de fotones únicos que es sintonizable y ultra-compacta. Estos resultados demuestran el potencial de los materiales 2D para controlar los emisores cuánticos y el uso de un objeto atómico para comprobar las propiedades optoelectrónicas y mecánicas que poseen los materiales atómicamente delgados.
14
Chik, Hope Wuming. "Emitter-up heterojunction bipolar transistor-compatible laser." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0014/MQ34129.pdf.
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Lee, Kon Jiun. "Current limiting of field emitter array cathodes." Diss., Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/19629.
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Manning, James David. "Directional diffuse reflection from a polygon emitter." Thesis, University of Hull, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.445284.
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Browne, David C. "Theoretical aspects of polysilicon emitter bipolar transistors." Thesis, University of Southampton, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328280.
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Adams, Andrew S. M. (Andrew C. )Massachusetts Institute of Technology. "An investigation of nafion electrospray emitter tips." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/130179.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, May, 2020Cataloged from student-submitted PDF of thesis.
Includes bibliographical references (pages 121-125).
Electrospray propulsion development is limited in large part by the materials with which emitters are manufactured. Emitters must transport ionic liquid to their apex and hold a shape which allows menisci to form and emit pure ions. The motivation for this work was to investigate Nafion, a perfluorinated sulfonic acid ionomer, as an alternative to the porous materials currently used for electrospray emitters. A common, repeatable method of manufacturing Nafion single emitter tips and arrays with different mixture ratios of Nafion and EMI BF₄ is developed and refined. This method utilizes 3D printed negatives with tungsten ILIS emitters to produce a master shape for reusable PDMS molds. Thirteen tips were made using the presented method. Defects are categorized and recorded. Three of the tips were also successfully attached to porous carbon substrates, all of which were mixtures. Molds for arrays were also tested, and an array of pure Nafion was made.
The Nafion emitter tips' hydraulic impedance is estimated from geometric parameters and separately calculated from emission characteristics. As part of the calculation, an estimation of (q/m)[subscript avg] is obtained using a previously obtained TOF curve. All tips exceeded the [mathematical expression] impedance threshold to emit pure ions. A tungsten ILIS emitter used as a master for tip shape is tested as a control. Four of thirteen tips were chosen for testing and all successfully emitted ions for a short period. Two emitted for >1 hr and displayed a decreasing emitted current over time, and the emitted current spanned over one order of magnitude (20 to 1000 nA). It is shown that this is likely due to the depletion of an externally wetted meniscus, and the mass flow thereafter was limited by the high hydraulic impedance of the Nafion bulk. The calculated impedance during steady-state emission was significantly lower than estimated for internal tranport alone.
Future study should improve understanding of Nafion-EMI BF₄ mixtures and their diffusivity given a pressure difference and a concentration of ionic liquid. In addition, to supplement previous work, an emission tests and an RPA curve are reported for a fifth Nafion tip.
by Andrew Adams.
S.M.
S.M. Massachusetts Institute of Technology, Department of Aeronautics and Astronautics
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Lourenço, Nuno Rafael Mendonça. "Communication systems using visible light : emitter/receiver." Master's thesis, Universidade de Aveiro, 2009. http://hdl.handle.net/10773/2097.
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Mestrado em Engenharia Electrónica e TelecomunicaçõesA presente dissertação aborda o design de um transdutor optoelectrónico para um sistema de comunicações sem fios que utiliza a luz visível como meio de transmissão. Estes sistemas tiram partido dos conhecimentos tecnológicos existentes sobre sistemas de comunicações sem fios utilizando o espectro dos infravermelhos, e da recente introdução em massa de díodos emissores de luz de elevado brilho em diversas aplicações de iluminação. O trabalho apresentado foi desenvolvido dentro do projecto VIDAS, tendo em conta os respectivos cenários de aplicação propostos. Este projecto visa aumentar a segurança rodoviária através da introdução de sistemas de comunicação com luz visível, para estabelecer ligações veículo-a-veículo e/ou veículo-a-semáforo. Através destas ligações, poderão ser antecipadamente fornecidos diversos avisos de segurança aos condutores. O estudo do transdutor proposto, começa com uma introdução ao conceito e evolução dos sistemas de comunicação com luz visível. Segue-se uma apresentação do canal de transmissão, na qual são definidos os modelos de emissor, receptor e propagação. São também discutidas as diversas fontes de ruído óptico e suas influências na aplicação pretendida. A restante análise é dividida em dois dispositivos principais, o emissor e o receptor ópticos. Sobre o emissor, são apresentados os principais blocos funcionais, seguidos de uma exposição das características de diversos díodos emissores de luz e da análise de diferentes topologias de receptor. Para a topologia mais viável de ser implementada, são apresentados diversos resultados de simulação do circuito electrónico. Do lado do receptor, de forma análoga, são apresentados os diferentes blocos funcionais e as características de diversos fotodíodos. No entanto a experiência do grupo de trabalho levou à escolha de uma topologia de receptor mais específica. Desta, fazem parte diversos módulos, cuja análise e resultados de simulação dos respectivos circuitos electrónicos são apresentados. De forma a avaliar a performance dos dispositivos propostos, foram efectuados diversos ensaios e respectivas medições. Estes resultados permitiram obter informações sobre o comportamento da componente óptica do sistema. Deste conjunto de informações, diferentes considerações sobre a performance de módulos individuais e do transdutor são apresentadas. Estas permitem concluir sobre a viabilidade do transdutor optoelectrónico num cenário de aplicação real. ABSTRACT: This dissertation addresses the design of an optoelectronic transceiver for a wireless communication system, using visible light as the transmission medium. These systems take advantage from the available technological expertise on wireless communication systems using the infrared spectrum, along with the recent massive introduction of high brightness light emitting diodes in several lighting applications. The present work was developed within the scope of project VIDAS, regarding the proposed application scenarios. This project aims at increasing road traffic safety by introducing visible light communication systems to establish vehicle-to-vehicle and vehicle-to-traffic light communications. Through these connections, early safety warnings can be provided to drivers. The study of the proposed transceiver begins with an introduction to the concept and evolution of visible light communication systems. This is followed by the presentation of the transmission channel, in which the emitter, receiver and transmission models are defined. Also, the sources and influences of the various optical noise sources are discussed. The remaining analysis is divided between the two major devices, the optical emitter and receiver. From the emitter, the main building blocks are presented, followed by an exposition of several light emitting diodes characteristics and the analysis of diverse receiver topologies. In the case of the most viable topology for implementation, several simulation results of the respective electronic circuit are presented. On the receiver, the main building blocks and the characteristics of several photodiodes are presented in a similar fashion. However, the workgroup experience led to the choice of a specific receiver topology. This is made up of several modules, whose analysis and simulation results for the electronic circuits are presented. In order to evaluate the performance of the proposed devices, several tests and measurements were made. These results also provided information on the system’s optical component behavior. From this assortment of information, different considerations on the performance of the individual modules, as well as the transceiver are presented. They allow for a conclusion on the viability of the optoelectronic transceiver in a real application scenari
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Mauersberg, Diane. "Rapid thermal processing of polysilicon emitter transistors /." Online version of thesis, 1994. http://hdl.handle.net/1850/11706.
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Jacobs, Kristof. "Development of resonant tunnelling diode terahertz emitter." Thesis, University of Sheffield, 2015. http://etheses.whiterose.ac.uk/9304/.
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This thesis reports on the development of high current density InGaAs/AlAs/InP resonant tunnelling diodes (RTDs) grown by metal-organic vapour phase epitaxy (MOVPE) for terahertz (THz) applications. A wide variety of characterisation techniques are employed to investigate the material properties and quality on the wafer level allowing future device and growth optimisation. An optical characterisation technique based on photoluminescence (PL) spectroscopy is developed to non-destructively map the doping and structural composition of the RTD on the wafer level. A new non-destructive optical characterisation technique to resolve the absolute energy level position of the first electron state of RTDs through low temperature PL spectroscopy is also reported. The absolute energy levels are resolved by a combination of type-I and type-II quantum well (QW) recombination, allowing an investigation into important scattering mechanisms affecting device performance, and monitor the QW alloy content and thickness non-destructively. Details of the growth process and the characterisation techniques are discussed. A new fabrication technique based on conventional i-line photolithography for micron scale high current density RTD devices is also developed with accurate control over the final device area (and hence characteristics). This is achieved by measuring the V-I characteristic of the RTD during the fabrication process, which has not been previously possible. This was made possible by guiding the emitter current through the full RTD structure by a large second contact electrode on the collector side and using an air-bridge contact to the collector. Important information about the RTD performance is extracted by using this method. Temperature dependent V-I characterisation is also carried out to investigate the valley current of the RTD. Details of the design, fabrication, and characterisation of a room temperature operating THz emitter in the 300 GHz band are reported.
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Revillon, Guillaume. "Uncertainty in radar emitter classification and clustering." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS098/document.
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En Guerre Electronique, l’identification des signaux radar est un atout majeur de la prise de décisions tactiques liées au théâtre d’opérations militaires. En fournissant des informations sur la présence de menaces, la classification et le partitionnement des signaux radar ont alors un rôle crucial assurant un choix adapté des contre-mesures dédiées à ces menaces et permettant la détection de signaux radar inconnus pour la mise à jour des bases de données. Les systèmes de Mesures de Soutien Electronique enregistrent la plupart du temps des mélanges de signaux radar provenant de différents émetteurs présents dans l’environnement électromagnétique. Le signal radar, décrit par un motif de modulations impulsionnelles, est alors souvent partiellement observé du fait de mesures manquantes et aberrantes. Le processus d’identification se fonde sur l’analyse statistique des paramètres mesurables du signal radar qui le caractérisent tant quantitativement que qualitativement. De nombreuses approches mêlant des techniques de fusion de données et d’apprentissage statistique ont été développées. Cependant, ces algorithmes ne peuvent pas gérer les données manquantes et des méthodes de substitution de données sont requises afin d’utiliser ces derniers. L’objectif principal de cette thèse est alors de définir un modèle de classification et partitionnement intégrant la gestion des valeurs aberrantes et manquantes présentes dans tout type de données. Une approche fondée sur les modèles de mélange de lois de probabilités est proposée dans cette thèse. Les modèles de mélange fournissent un formalisme mathématique flexible favorisant l’introduction de variables latentes permettant la gestion des données aberrantes et la modélisation des données manquantes dans les problèmes de classification et de partionnement. L’apprentissage du modèle ainsi que la classification et le partitionnement sont réalisés dans un cadre d’inférence bayésienne où une méthode d’approximation variationnelle est introduite afin d’estimer la loi jointe a posteriori des variables latentes et des paramètres. Des expériences sur diverses données montrent que la méthode proposée fournit de meilleurs résultats que les algorithmes standardsIn Electronic Warfare, radar signals identification is a supreme asset for decision making in military tactical situations. By providing information about the presence of threats, classification and clustering of radar signals have a significant role ensuring that countermeasures against enemies are well-chosen and enabling detection of unknown radar signals to update databases. Most of the time, Electronic Support Measures systems receive mixtures of signals from different radar emitters in the electromagnetic environment. Hence a radar signal, described by a pulse-to-pulse modulation pattern, is often partially observed due to missing measurements and measurement errors. The identification process relies on statistical analysis of basic measurable parameters of a radar signal which constitute both quantitative and qualitative data. Many general and practical approaches based on data fusion and machine learning have been developed and traditionally proceed to feature extraction, dimensionality reduction and classification or clustering. However, these algorithms cannot handle missing data and imputation methods are required to generate data to use them. Hence, the main objective of this work is to define a classification/clustering framework that handles both outliers and missing values for any types of data. Here, an approach based on mixture models is developed since mixture models provide a mathematically based, flexible and meaningful framework for the wide variety of classification and clustering requirements. The proposed approach focuses on the introduction of latent variables that give us the possibility to handle sensitivity of the model to outliers and to allow a less restrictive modelling of missing data. A Bayesian treatment is adopted for model learning, supervised classification and clustering and inference is processed through a variational Bayesian approximation since the joint posterior distribution of latent variables and parameters is untractable. Some numerical experiments on synthetic and real data show that the proposed method provides more accurate results than standard algorithms
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Celebi, M. bahadir. "Radar Emitter Emulation For Research And Experimental Purposes." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/3/12610847/index.pdf.
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The scope of this thesis is to implement radar emitter emulator in a low cost, portablehardware for operational and educational purposes. The model enables pulse train generation in real environment belonging to radar emitters for military exercises. The motivation comes from another research area which is to design effective algorithms for
deinterleaving mixed pulse sequences in a suitable hardware and this thesis, covers the work done for implementing a hardware that generates mixed pulse sequences. First of
all, a basic radar emitter model is built up using laboratory instruments by considering basic radar emitter models. Technical specs of these instruments have to be known well
to find out how many emitters can be emulated simultaneously and what the limits of these emulations are. After giving emulation results, trigging signal generator externally to obtain complex mixed pulse sequences is mentioned. In the following section related schematics are given about implementing radar emitters. Cost efficient way of emitter emulation is mentioned by using wideband RF synthesizer/VCO with integrated RF mixers and some microwave components in the following section. A board is designed including all required components to implement radar emitter emulation. Tests are implemented in laboratory environment. Finally test results and technical specifications
of the design are given. Also cost calculations of the implemented designs are done in the final section and some examples related to the use of emulators in environmental
scenarios are given. Future work is also explained again in this final section.
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Pflug, David George. "Low voltage field emitter arrays through aperture scaling." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/8804.
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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2000.Includes bibliographical references (p. 215-223).
by David George Pflug.
Ph.D.
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Liu, Yin. "Design and Fabrication of the Emitter Controlled Thyristor." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/33671.
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The Emitter Controlled Thyristor (ECT) is a new MOS-Gated Thyristor (MGT) that combines the ease of a MOS gate control with the superior current carrying capability of a thyristor structure for high-power applications. An ECT is composed of an emitter switch in series with the thyristor, an emitter-short switch in parallel with the emitter junction of the thyristor, a turn-on FET and the main thyristor structure. Numerical analysis shows that the ECT also offers superior high voltage current saturation capability even for high breakdown voltage ratings. Two different ECT structures are investigated in this research from numerical simulations to experimental fabrications.
A novel ECT structure that utilizes IGBT compatible fabrication process was proposed. The emitter short FET, emitter switch FET and turn-on FET are all integrated with a high voltage thyristor. Numerical simulation results show that the ECT has a better conductivity modulation than that of the IGBT and at the same time exhibits superior high voltage current saturation capability, superior FBSOA and RBSOA. The technology trade-off between turn-off energy loss and forward voltage drop of the ECT is also better than that of the IGBT because of the stronger conductivity modulation. A novel self-aligned process is developed to fabricate the device. Experimental characteristics of the fabricated ECT devices show that the ECT achieves lower forward voltage drop and superior high voltage current saturation capability.
A Hybrid ECT (HECT) structure was also developed in this research work. The HECT uses an external FET to realize the emitter switching function, hence a complicated fabrication issue was separated into two simple one. The cost of the fabrication decreases and the yield increases due to the hybrid integration. Numerical simulations demonstrate the superior on-state voltage drop and high voltage current saturation capability. A novel seven-mask process was developed to fabricate the HECT. Experimental results show that the HECT could achieve the lower forward voltage drop and superior current saturation capability. The resistive switching test was carried out to demonstrate the switching characteristics of the HECT.Master of Science
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Sykora, Benedikt Reinhold. "Influence of emitter orientation in perylene based OLEDs." Master's thesis, Universidade de Aveiro, 2013. http://hdl.handle.net/10773/11828.
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Mestrado em Ciência e Engenharia de MateriaisOs díodos orgânicos emissores de luz (organic light-emitting diodes ou OLEDs) têm como elemento funcional um filme fino de um semicondutor orgânico para a criação de excitões (pares electrão-lacuna), que emitem luz quando relaxam. O objetivo desta dissertação de mestrado é investigar o efeito da orientação dipolar de filmes baseados em perilenos de tetraphenyldibenzoperiflanthene (DBP) e diindenoperylene ( DIP), e das mesmas moléculas dispersas numa ma matriz de 5,6,11,12- tetraphenylnaphthacene (rubreno). O estudo tenta identificar uma possível relação entre o comportamento destes filmes e a eficiência do respetivo OLED. Observa-se que os filmes de DBP são amorfos, apresentam uma superfície lisa e absorvem mais luz do que os filmes de DIP, que se caracterizam por uma estrutura cristalina e uma superfície irregular. Os resultados combinados de simulações e de medições de fotoluminescência com dependência angular revelam que as moléculas de DBP apresentam orientação horizontal, estando as moléculas de DIP orientadas verticalmente. Este facto pode explicar o acoplamento mais forte das moléculas de DIP aos plasmões de superfície, em comparação com o DBP. As características gerais dos filmes de DBP ou DIP mantêm-se mesmo quando estes são depositados nos substratos de N, N '-di(1-naftil-N,N-difenil-(1,1'- bifenil)-4,4' –diamina utilizados ma preparação dos OLEDs, o que permite a comparação direta entre as duas configurações. Os resultados obtidos com os OLEDs baseados em filmes puros de DBP ou DIP apresentam valores de eficiência quântica externa (EQE) da ordem de 0,2 e 0,04 %, respetivamente. Estes valores baixos podem explicar-se pela orientação vertical dos dipolos do DIP, conduzindo a um fator de emissão de 27% (light outcoupling), claramente superior ao obtido com o OLED baseado no DBP (16%). Estas diferenças acentuam-se quando na comparação destes filmes com o comportamento dos filmes rubreno equivalentes dopados com 1% de DBP e DIP. Se por um lado não se observa nenhuma orientação dipolar preferencial no caso do DIP, as moléculas de DBP na matriz de rubreno estão quase na sua totalidade orientadas horizontalmente, o que aumenta o factor de emissão. A forte orientação preferencial no caso do DBP pode igualmente justificar o aumento de EQE de 0,2 % e 0,04% nos OLEDs com os filmes puros de DBP e DIP, para 3% e 0,5% no caso dos OLEDs com os filmes dopados. O aumento da eficiência pode também dever-se ao aumento da transferência energética da matriz de rubreno para os centros emissores. O forte efeito da orientação horizontal do emissor na eficiência dos OLEDs manifesta-se igualmente no notável aumento do factor de emissão de luz observado entre os filmes de DBP (fortemente orientados) e DIP (pouco orientados), que é de cerca de 70% no caso das camadas de emissão baseadas nos filmes puros, e de 44 % no caso dos filmes dopados.
Organic light-emitting diodes (OLEDs) contain thin films of organic semiconductors to create excitons (electron-hole-pairs), which will emit light if they de-excite. The aim of this master thesis is to investigate a possible link between the dipole orientation of perylene based films of tetraphenyldibenzoperiflanthene (DBP) and diindenoperylene (DIP), and of the same molecules dispersed in a 5,6,11,12-tetraphenylnaphthacene matrix. The study also compares the behavior of these films with that of the corresponding OLEDs. It is shown that DBP neat films are essentially amorphous, with a rather smooth surface and they absorb more light than the DIP films, which are crystalline and have a rough surface. Simulation results and angle-dependent p-polarised photoluminescence measurements reveal that the DBP molecules have a horizontal orientation, while the DIP molecules are vertically oriented. This explains the stronger coupling of DIP molecules to the surface plasmons, when compared to the DBP molecules. The general characteristics of the DBP or DIP films do not change when these are deposited onto N,N’-di(1-naphtyl-N,N’-diphenyl-(1,1’-biphenyl)-4,4’diamine hole transport layers used as substrates in OLEDs, thus allowing a direct comparison between both configurations. The OLEDs comprising neat films of DBP or DIP have small external quantum efficiency (EQE) values of 0.2 and 0.04%, respectively. This is probably due to the strong vertical molecular orientation of the DBP, leading to a high lightoutcoupling factor of 27%, when compared to 16% of the DIP OLED. These differences are accentuated when comparing the behavior of the neat films with equivalent rubrene films doped with 1% of DBP or DIP. While the DIP exhibits a rather isotropic orientation, the DBP molecules are fully horizontal within the doped film, thus improving the light-outcoupling. This may partly justify the increase of EQE from 0.2% and 0.04% of the neat film OLEDs to 3% and 0.5% for the doped DBP and DIP OLEDs, respectively. The improvement of the efficiency may also be due to the enhancement of the energy transfer from the rubrene matrix to the emitter dyes. The horizontal orientation of the emitter has a huge effect on the efficiency of perylene-based OLEDs, apparent also on the remarkable increase of the lightoutcoupling of strongly oriented DBP dipoles in comparison to the weakly oriented DIP, which is of the order of 70% in the case of the neat emission layers, and of 44% in the case of the doped counterparts.
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Godbole, Soumitra Kumar. "Stability of Field Emitter Arrays to Oxygen Exposures." Thesis, University of North Texas, 2002. https://digital.library.unt.edu/ark:/67531/metadc3346/.
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The purpose of these experiments was to determine the degradation mechanisms of molybdenum based field emitter arrays to oxygen exposures and to improve the overall reliability. In addition, we also evaluated the emission current stability of gold-coated field emitter arrays to oxygen exposures. oxygen at 1x10-6 torr was introduced into the chamber through a leak valve for different lengths of time and duty cycles.
To ensure identical oxygen exposure and experimental measurement conditions, tips on half the area of the FEA were fully coated with gold and the other half were left uncoated. The emission current from the gold coated half was found to degrade much less than that from the uncoated half, in the presence of oxygen. Also in the absence of oxygen, the emission current recovery for the gold-coated side was much quicker than that for the uncoated side.
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Schucker, Thomas Douglas, and Thomas Douglas Schucker. "Emitter Source Geolocation from Imparted Rotor Blade Modulation." Thesis, The University of Arizona, 2016. http://hdl.handle.net/10150/623262.
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In RF communications with a rotorcraft such as a helicopter, the rotor blades can impart a modulation onto the received signal called Rotor Blade Modulation (RBM). This modulation is caused by the reflection of a signal off the rotating blades. The reflected signal is Doppler shifted based on where the signal is reflected along the length of the blade as well as the angle between the axis of rotation and the emitter. RBM is known to degrade the performance of RF communications on rotorcraft and can be used in radar applications to detect and classify aircraft, but there is little on its usefulness in other areas. This thesis looks at the ability to utilize the RBM phenomenon on the rotorcraft itself to geo-locate and track a signal emitter on the ground. To do this a 3D RF ray tracing program was developed in C++ to produce simulations of RBM signals. The developed program is based on optical ray tracing algorithms with modified physical propagation effects for RF signals, and swapping lights and cameras for RF transmitters and receivers respectively. The ray tracer was then run over a realistic set of physical parameters to determine their effects on the received signal; this includes transmitter azimuth and elevation angle, receiver position, blade pitch, etc. along with their combinations. The simulations of the azimuth and elevation angle produce predictable modulations on the received signal. Based on the trends in the signal's modulation, a DSP algorithm was distilled down that accurately determines the azimuth and elevation angle of the transmitter from simulated signal data.
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Patra, Soumyadip. "Distributed Emitter Detector Design under Imperfect Communication Channel." ScholarWorks@UNO, 2017. http://scholarworks.uno.edu/td/2391.
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We consider the distributed detection of an emitter using multiple sensors deployed at deterministic locations. The signal from the emitter follows a signal attenuation model dependent on the distance between the sensor and the emitter. The sensors transmit their decisions to the fusion center through a parallel access Binary Symmetric Channel (BSC) with a cross-over probability. We seek to optimize the detection performance under a prescribed false alarm at the sensor level and at the system level. We consider the triangular topology structure and using the least favorable emitter range study the impact of the BSC on the system level detection fusion rules. The MAJORITY fusion rule is found to be optimal under certain conditions.
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Papadopoulos, George 1961 Carleton University Dissertation Engineering Electrical. "Development and characterization of polysilicon emitter solar cells." Ottawa.:, 1989.
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Li, Liurui. "Multiplexed Electrospray Emitters for Highly Conductive and Corrosive Fluids." Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/78199.
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This thesis reports the design, fabrication, and operation of silicone based multiplexed electrospray (MES) emitters. After reviewing the feasibility of utilizing electrospray as a scalable thin film deposition technique as well as the advantages and limitations of prior MES emitters, we present a design rationale for MES suitable for highly conductive and corrosive fluids. Then we customized a 1064nm fiber laser micromachining system to precisely and rapidly machine silicone sheet and silicon wafers. Laser energy and path are judicially chosen to create clean and round micro posts that form the external structure of the nozzles. For MES with low flow rate per nozzle, it is of vital importance to evenly distribute the liquid into each nozzle on the entire MES array by controlling the pressure drop inside each fluid flow channel. To this end, we modeled the dimension of microfluidic channels that introduce flow impedance overwhelming surface tension at the nozzle tip. We presented laser microfabrication techniques for fabricating two typical types of microfluidic channels: the through-hole array on conductive silicone sheets and the in-plane microfluidic channel on silicon wafers. Next, we developed a convenient assemble process for the integration of three layers (distributor layer, extractor layer, and collector layer) of the MES emitter. The uniformity of the flow rate among nozzles on MES emitters was investigated by observing the overall spray profiles and measuring the diameter of each jet. The results suggest that the silicone-based MES emitters are feasible for spraying highly conductive and corrosive liquids. The MES emitter developed in this thesis may become a promising tool in the scalable manufacturing of thin film perovskite solar cells.Master of Science
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Liu, Kendrick Xuong. "Photo-excitation of gated p-silicon field emitter arrays /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2005. http://uclibs.org/PID/11984.
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Ureten, Suzan. "Single and Multiple Emitter Localization in Cognitive Radio Networks." Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/35692.
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Cognitive radio (CR) is often described as a context-intelligent radio, capable of changing the transmit parameters dynamically based on the interaction with the environment it operates. The work in this thesis explores the problem of using received signal strength (RSS) measurements taken by a network of CR nodes to generate an interference map of a given geographical area and estimate the locations of multiple primary transmitters that operate simultaneously in the area. A probabilistic model of the problem is developed, and algorithms to address location estimation challenges are proposed. Three approaches are proposed to solve the localization problem. The first approach is based on estimating the locations from the generated interference map when no information about the propagation model or any of its parameters is present. The second approach is based on approximating the maximum likelihood (ML) estimate of the transmitter locations with the grid search method when the model is known and its parameters are available. The third approach also requires the knowledge of model parameters but it is actually based on generating samples from the joint posterior of the unknown location parameter with Markov chain Monte Carlo (MCMC) methods, as an alternative for the highly computationally complex grid search approach.
For RF cartography generation problem, we study global and local interpolation techniques, specifically the Delaunay triangulation based techniques as the use of existing triangulation provides a computationally attractive solution. We present a comparative performance evaluation of these interpolation techniques in terms of RF field strength estimation and emitter localization. Even though the estimates obtained from the generated interference maps are less accurate compared to the ML estimator, the rough estimates are utilized to initialize a more accurate algorithm such as the MCMC technique to reduce the complexity of the algorithm. The complexity issues of ML estimators based on full grid search are also addressed by various types of iterative grid search methods. One challenge to apply the ML estimation algorithm to multiple emitter localization problem is that, it requires a pdf approximation to summands of log-normal random variables for likelihood calculations at each grid location. This inspires our investigations on sum of log-normal approximations studied in literature for selecting the appropriate approximation to our model assumptions. As a final extension of this work, we propose our own approximation based on distribution fitting to a set of simulated data and compare our approach with Fenton-Wilkinson's well-known approximation which is a simple and computational efficient approach that fits a log-normal distribution to sum of log-normals by matching the first and second central moments of random variables. We demonstrate that the location estimation accuracy of the grid search technique obtained with our proposed approximation is higher than the one obtained with Fenton-Wilkinson's in many different case scenarios.
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Tilston, Nina M. "Common emitter augmentation : a linearisation technique for RF amplifiers." Thesis, Heriot-Watt University, 2005. http://hdl.handle.net/10399/219.
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Bradley, Susan Margaret. "The numerical simulation of polysilicon-contacted emitter bipolar transistors." Thesis, Queen's University Belfast, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317060.
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De, La Torre James David. "Modeling of cone deposition process for field emitter displays." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/40598.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1996.Includes bibliographical references (leaf 58).
by James David De La Torre.
M.Eng.
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Dias, Stiven Schwanz. "Collaborative emitter tracking using distributed sequential Monte Carlo methods." Instituto Tecnológico de Aeronáutica, 2014. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=3137.
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We introduce in this Thesis several particle filter (PF) solutions to the problem of collaborative emitter tracking. In the studied scenario, multiple agents with sensing, processing and communication capabilities passively collect received-signal-strength (RSS) measurements of the same signal originating from a non-cooperative emitter and collaborate to estimate its hidden state. Assuming unknown sensor noise variances, we derive an exact decentralized implementation of the optimal centralized PF solution for this problem in a fully connected network. Next, assuming local internode communication only, we derive two fully distributed consensus-based solutions to the problem using respectively average consensus iterations and a novel ordered minimum consensus approach which allow us to reproduce the exact centralized solution in a finite number of consensus iterations. In the sequel, to reduce the communication cost, we derive a suboptimal tracker which employs suitable parametric approximations to summarize messages that are broadcast over the network. Moreover, to further reduce communication and processing requirements, we introduce a non-iterative tracker based on random information dissemination which is suited for online applications. We derive the proposed random exchange diffusion PF (ReDif-PF) assuming both that observation model parameters are perfectly known and that the emitter is always present. We extend then the ReDif-PF tracker to operate in scenarios with unknown sensor noise variances and propose the Rao-Blackwellized (RB) ReDif-PF. Finally, we introduce the random exchange diffusion Bernoulli filter (RndEx-BF) which enables the network of collaborative RSS sensors to jointly detect and track the emitter within the surveillance space.
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Zhang, Bin. "Development of the Advanced Emitter Turn-Off (ETO) Thyristor." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/26095.
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Advancements in the power electronics systems have been directly related to the availability of improved power semiconductor devices. The device performance greatly determines the efficiency, reliability, volume, and cost of the power electronics system. This dissertation is dedicated to develop an advanced high power semiconductor device, the emitter turn-off (ETO) thyristor, which is targeted to improve the limitations of the present high power devices.
Major improvements in electrical and mechanical designs of the ETO for high power and high frequency operation are proposed which result in improved snubberless turn-off capability, low conduction loss, and low gate drive power consumption of the new generation ETO.
A revolutionary self-power generation method of the ETO is proposed. Different from the conventional high power devices which require the external power input for their gate drivers, ETO achieves complete optically controlled turn-on and turn-off and all the internal power required is self-generated. This advancement will have a major impact to high power converter designs.
A novel integrated method to eliminate the dead-time requirement is proposed for ETO. This method not only improves the output waveform quality but also increases the reliability and reduces the cost of the high power PWM voltage source converters. With this unique function, the upper and the lower ETO's within a converter phase leg can receive the ideal complementary (without dead-time) PWM signals and solve shoot-through problems.
Method to measure the ETO current and transfer the current information to a PWM signal is proposed. Based on the ETO's built-in current sensor, the over-current protection function of the ETO is designed as well. The experimental results show that the built-in current sensor has a very high precision, and the over-current protection function can effectively protect the ETO during the short circuit faults.
In order to improve ETO's turn-off capability, a comprehensive investigation of the turn-off failure mechanism of the ETO was performed. A series of simulations and experiments are carried out to study the ETO turn-off operation. The detail turn-off failure mechanisms are presented. The conditions to cause the ETO failure are addressed. The approaches to improve the ETO's turn-off capability are discussed.Ph. D.
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Cicek, Kenan. "Characterisation of orbital angular momentum beam emitter and receiver." Thesis, University of Bristol, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.702751.
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This thesis presents theoretical, simulation and experimental based studies on emission/detection of orbital angular momentum (OAM) beams for the newly emerging integrated OAM photonics technology. The number of applications that utilise the OAM technology has been increasing since the time it has been discovered. Optical communication is one of the high potential applications of OAM beams because of the possibility of providing infinite number of states. This has been considered as the perfect solution for the increasing data load. In order to process the OAM concept in such optical systems, a number of methods have been proposed. In addition to these methods, a new PICs OAM interpretation method has been discussed in this study. The obtained results show that this method has the potential especially for high-capacity optical data transmission. Moreover, the purity of beams (in terms of reflection within the ring resonator) generated by an integrated vortex beam emitter which was proposed by our group-has been investigated for the first time in this study. The investigation showed that there is a disrupting feed-back beam exist within the system. However, its effect on the generated beam's purity is considerably low.
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Greco, Angelo. "Optimization of homogeneous emitter and thin-film solar cells." Doctoral thesis, Università di Catania, 2014. http://hdl.handle.net/10761/1547.
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Over the last decades the world has been experimenting an increasing pressure to find solutions to energy crisis issues. As a result, the scientific research has been boosted towards the development of solutions related to alternative energy sources.
In this context, several research programs have been supported. Among them, the ENIAC Project Joint Undertaking, Energy for a green society: from sustainable harvesting to smart distribution, equipment, materials, design solutions and their applications, within which the present work has been performed.
In particular, this thesis is focused on the optimization of photovoltaic cells, through the use of mathematics tools and optimization techniques based on new theories like the Genetic Algorithm ones.
The obtained results are new and they represent a noticeable improvement in the optimization of solar cells design and efficiency.
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Bhagat, Kishna Nand. "Numerical simulation of paper drying process under infrared radiation emitter." Cincinnati, Ohio : University of Cincinnati, 2008. http://www.ohiolink.edu/etd/view.cgi?acc%5Fnum=ucin1204220932.
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Thesis (M.S.)--University of Cincinnati, 2008.Advisor: Dr. Milind A. Jog. Title from electronic thesis title page (viewed Apr.30, 2008). Includes abstract. Keywords: Paper Drying, Infrared Radiation, Numerical Simulation, Finite Volume, Emissivity, Parametric Study. Includes bibliographical references.
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Buchhauser, Dirk [Verfasser]. "Weiße Emitter in OLEDs für Vollfarbdisplays und Beleuchtungszwecke / Dirk Buchhauser." Aachen : Shaker, 2007. http://d-nb.info/1164338579/34.
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Siabi-Shahrivar, Nasser. "A study of 1/f noise in polysilicon emitter transistors." Thesis, University of Southampton, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314728.
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Hope, Adam John. "Fluorinated emitter molecules for triplet-triplet annihilation up-conversion media." Thesis, Durham University, 2014. http://etheses.dur.ac.uk/10623/.
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This thesis details the synthesis, characterisation and photophysical properties of various fluorinated emitters for triplet-triplet annhilation up-conversion systems. The theory and mechanism of TTAUC is evaluated and the molecular design of the annihilating emitter molecule reviewed to allow improvement of the external up-conversion quantum yield and overall energy efficiency of the process. Three main series of chromaphores were investigated, based on diphenylanthracenes, bisphenylperylenes, and 3,5,8-triphenylBODIPYs. These were synthesised by metal catalysed aryl-aryl coupling (Suzuki-Miyaura) or nucleophilic substitution reactions and, when paired with appropriate sensitizing molecules, allowed the up-conversion of green to blue; red to green; and near IR/red to orange respectively. The effect of increasing fluorination on the ease of synthesis and photophysical properties of these emitter systems was studied with a view to their application in up-conversion systems. Fluorinated emitter molecules were shown to be highly resistant to degradation by UV light compared to their non-fluorinated analogues. The up-conversion ability of these systems was evaluated and novel fluorinated BODIPY based dyes were produced that have high fluorescence quantum yields of over 90%. Finally the up-conversion of up-converting nanoparticles incorporating fluorinated emitters was evaluated.
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BHAGAT, KISHNA NAND. "Numerical simulation of paper drying process under infrared radiation emitter." University of Cincinnati / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1204220932.
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Park, Sang Hoon. "Fabrication of submicron self-aligned regrown emitter heterojunction bipolar transistors /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1997. http://wwwlib.umi.com/cr/ucsd/fullcit?p9804510.
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Hu, Xi. "Network and sensor management for mulitiple sensor emitter location system." Diss., Online access via UMI:, 2008.
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Thesis (Ph. D.)--State University of New York at Binghamton, Thomas J. Watson School of Engineering and Applied Science, Department of Electrical and Computer Engineering, 2008.Includes bibliographical references.
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Hajra, Mahua. "Surface treatment and surface coating of silicon field emitter array /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2003. http://uclibs.org/PID/11984.
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Steffes, Christian [Verfasser]. "Exploiting Structural Signal Information in Passive Emitter Localization / Christian Steffes." Bonn : Universitäts- und Landesbibliothek Bonn, 2017. http://d-nb.info/1139049003/34.
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Trifon, George Sebastian. "ERBIUM DOPED CERAMIC NANOFIBER SYNTHESIS FOR THERMOPHOTOVOLTAIC SELECTIVE EMITTER APPLICATIONS." OpenSIUC, 2012. https://opensiuc.lib.siu.edu/theses/1027.
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This thesis explored the development of isothermal selective emitters for harvesting thermal energy to be used in conjunction with photovoltaic cells. The selective emitters were Erbium doped Titania nanofibers and Erbium and Yttrium doped Titania nanofibers that may be used with a Gallium Antimonide photovoltaic cell. The ultimate aim of this research was to develop Erbium doped Yttrium Titanate nanofibers. This research is of importance in recovering heat from a number of resources including power plant boilers. The thermal energy lost in the boilers can be as high as 20% of the input fuel energy and a recovery of this energy would boost the thermal performance of the power plants. It has been observed that the temperatures of the flue gas reaching the heat recovery region may be higher than 1600K and the radiation and convective losses in the burner occurs at even higher temperatures. Thermophotovoltaics (TPV) offer a solution in terms of converting the thermal energy to electricity without any moving parts. The efficiencies of conventional TPVs are very small (10 - 20%) and thus not a solution as the primary electric generator. However, in the field of the harvesting of waste energy, TPVs have tremendous potential. In order to improve efficiencies, Erbia (which can absorb thermal energy and convert it to electromagnetic radiation with a narrow wavelength spectrum with mean wavelength of 1500nm) can be used as a selective emitter with GaSb PV cells (which have its maximum efficiency in the same wavelength range) as the collector. In order to further improve its performance, the Erbia was proposed to be supported by Titania, which is transparent to IR in this range. However, past research has shown that the Erbia doped Titania nanofibers essentially have Erbium in the form of pyrochlore Erbium Titanate. Thus the research focused on a way to synthesize ErxY2-xTi2O7 pyrochlore structure to act as the selective emitter. The self-supporting composite was designed to be nanostructured to ensure isothermal operation and a high surface to volume ratio to minimize re-adsorption and to have a compact design. The nanofiber emitters were prepared by electrospinning. This thesis demonstrated a synthesis procedure of optically selective nano-composites using electrospinning.