High Voltages
Mostrando 13-24 de 85 artigos, teses e dissertações.
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13. CMOS image system wiht high responsivity and high dynamic range / Sistemas de imagem CMOS com alta responsividade e elevada faixa dinamica
This thesis adresses two important challenges imposed by CMOS technology trends, the reduction of the junctions s responsivity and voltages levels. A new photodetector with high responsivity and a multi-sampling time domain image system are investigated. This thesis proposes to use the gate controlled lateral bipolar junction transistor (GCLBJT) as a four te
Publicado em: 2008
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14. Classificação e localização de faltas em linhas de transmissão usando diferentes arquiteturas de redes neurais artificiais. / Classification and location faults in transmission lines, using different artificial neural networks architectures.
This work presents the development of algorithms for determination of the estimate of the distance of occurrence of fault in a high voltage transmission line, in relation to a local terminal, and also the classification of the fault type, using techniques based on artificial neural networks. The tests and the validation of the proposed algorithms are made us
Publicado em: 2008
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15. Characterization of cadmium and zinc telluride (CZT) and pin type silicon (Si-Pin) photodiode detectors for x-ray spectrometry / Characterization of cadmium and zinc telluride (CZT) and pin type silicon (Si-Pin) photodiode detectors for x-ray spectrometry / CaracterizaÃÃo dos detectores de telureto de cÃdmio e zinco (CZT) e fotodiodo de silÃcio tipo pin (Si-PIN) para a espectrometria de raios-x / CaracterizaÃÃo dos detectores de telureto de cÃdmio e zinco (CZT) e fotodiodo de silÃcio tipo pin (Si-PIN) para a espectrometria de raios-x
A detailed understanding of X-ray spectrum is essential for analyzing equipment that emits this kind of radiation in radiodiagnostic facilities. Information on the various parameters that are contained in this spectrum is important for quality control of X-ray equipment. Spectrometry of X-ray beams uses very often GeHP detectors, that have good detection eff
Publicado em: 2008
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16. Evaluation of the Characteristics of Lightning Return Stroke Electromagnetic Fields Generated by Cloud-to-Ground Lightning. / Avaliação do Comportamento dos Campos Eletromagnéticos Gerados por Descargas Atmosféricas Nuvem-Terra
The occurrence of lightning discharges causes a significant amount of unscheduled supply interruptions in overhead lines of electricity systems, contributing to decrease quality indicators of these systems, even in the case of regions with moderated ground flash density. Focusing on the distribution systems, great part of the problems are related to the indu
Publicado em: 2007
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17. Fonte CA ressonante de alta tensão para ozonizadores / High-voltage AC resonant source for ozonizers
O ozônio se apresenta como um excelente produto químico para ser usado em substituição ou em conjunto com o cloro para o tratamento de água. O ozônio é um potente bactericida e viricida e não deixa resíduos no meio ambiente. A produção deve ser local e requer apenas ar e eletricidade. Um método simples e eficaz para a produção de ozônio é atr
Publicado em: 2007
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18. CARACTERIZAÇÃO DE ATUADORES BASEADOS EM MÚSCULOS ARTIFICIAIS POLIMÉRICOS POR EFEITO CAPACITIVO / CHARACTERIZATION OF ACTUATORS BASED ON POLYMERIC ARTIFICIAL MUSCLES WITH CAPACITIVE EFFECT
It is well known the needs of finding new technologies for robotic systems actuations, with the same efficiency of the natural muscles. The common actuators have better agility and force when compared to natural muscles, but the dimensions and weight are bigger and for that the demand of energy necessary for the actuation is higher. Smaller and cheaper robot
Publicado em: 2007
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19. Nanomanipulation and characterization of individual nano-objects for in situ experiments of electron microscopy / Nanomanipulação e caracterização de nano-objetos individuais por experimentos in situ de microscopia eletronica
It is expected that, in the future, high-technology devices should be based on new and unexpected physical and chemical properties of nanometric objects. Many applications require nano-objects to be selectively positioned at well-defined positions of a device. However, the well-established methods of physical manipulation used in the macroscopic scale are no
Publicado em: 2007
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20. Project of circuits for generation of voltage reference in receiving/transmitting RF systems. / Projeto de circuitos para geração de tensão de referência em sistemas receptores/transmissores RF.
This work consists in the design of a CMOS Voltage Reference Source with a temperature coefficient inferior to 50 ppm/ºC. This voltage source should be applied in radio frequency receptor/transmitter but can be also applied in any analog system. The technology employed in the design is the CMOS 0.35 µm from the AMS (Austria Micro Systems) with four metal l
Publicado em: 2007
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21. Optical voltage transformers using white light interferometry for high voltage measurements. / Transformador óptico por interferometria de luz branca para medição de altas tensões.
A new approach to perform measurement of potentials in high voltage levels using electrooptical Pockels sensors is presented here. This work describes an application of the White Light Interferometry technique to a high voltage optical fiber measurement system. In this system the information is encoded in the spectrum of the light, allowing the measurement t
Publicado em: 2006
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22. Nitretação iônica sem efeito de borda :desenvolvimento e avaliação de uma nova técnica
The ionic nitriding process presents some limitations related with the control of the thickness of the layer and its uniformity. Those limitations that happen during the process, are produced due to edge effects, damage caused by arcing arc and hollow cathode, mainly in pieces with complex geometry and under pressures in excess of 1 mbar. A new technique, de
Publicado em: 2006
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23. Controle e integração de centrais eólicas à rede elétrica com geradores de indução duplamente alimentados. / Control and integration of wind farms to the power grid using doubly fed induction generators.
This Thesis presents the control and integration of wind farms to the interconnected power grid, using doubly fed induction generators (DFIG). The main objective of the present Thesis was to develop discrete control strategies for the wind generation system, with the goal to reduce the wind variations impacts in the grid power quality. The design technique s
Publicado em: 2006
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24. Avaliação da técnica de eletrodiálise para a separação de ácido lactobiônico produzido por via biotecnológica
Glicose-fructose oxidoreductase (GFOR) and glicono-d-lactonase (GL) enzymes are present in Zymomonas mobilis bacteria cells. These enzymes are capable to catalyze lactobionic acid (AL) formation (or formation of its correspondent salts) together with sorbitol from lactose and fructose. Lactobionic acid and sodium lactobionate have important applications in m
Publicado em: 2006