Photodetector
Mostrando 1-12 de 16 artigos, teses e dissertações.
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1. Determining the Fixed Pattern Noise of a CMOS Sensor: Improving the Sensibility of Autonomous Star Trackers
ABSTRACT: Autonomous star trackers are optical-electronic devices used for attitude determination of artificial satellites, having as a reference for this computation the positions of stars. There is one autonomous star tracker in development at the Aerospace Electronics Division of the Brazilian National Institute for Space Research. The autonomous star tra
J. Aerosp. Technol. Manag.. Publicado em: 2013-06
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2. Desenvolvimento de um equipamento portátil e de sistema de análises em fluxo empregando multicomutação. Determinação fotométrica de ferro em águas de rios / Development of a portable equipment and a flow analysis system employing multicommutation. Photometric determination of iron in river waters
Iron is the most abundant element on Earth and plays an important role in biogeochemical cycles. In this work, an automatic analytical procedure was developed for the photometric determination of iron in river waters, employing a LED-based photometer and solenoid mini-pumps for solution handling. The proposed procedure was based on the reaction between iron
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 20/07/2011
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3. Caracterização de fotodetectores de infravermelho a poços quânticos.
Este trabalho apresenta a caracterização eletro-óptica de fotodetectores para o infravermelho operando nas janelas atmosféricas de ondas médias e longas. Utilizou-se sensores QWIP (Quantum Well Infrared Photodetector) baseados em estruturas semicondutoras de poços quânticos múltiplos de GaAs/AlGaAs e InGaAs/AlInAs, utilizando transições intrabanda.
Publicado em: 2009
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4. 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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5. Three-band quantum well infrared photodetector using interband and intersubband transitions.
This thesis presents the modeling, design, fabrication and characterization of a quantum well infrared photodetector (QWIP) capable of detecting near infrared (NIR), mid wavelength infrared (MWIR) and long wavelength infrared (LWIR), simultaneously. The NIR detection was achieved using interband transition while MWIR and LWIR were based on intersubband trans
Publicado em: 2008
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6. Development of portable photometer using led photodetector and automatic analytical procedures employed multicommutation in flow analisis / Desenvolvimento de um fotômetro portátil usando LED como fotodetector e de procedimentos analíticos automáticos empregando multicomutação em fluxo
Este trabalho compreende o desenvolvimento de um fotômetro portátil empregando um LED (Light Emitting Diode) como fonte de radiação eletromagnética e outro LED como fotodetector. A viabilidade desta proposta foi demonstrada em um procedimento de titulação fotométrica automática, implementado baseado no processo de procura binária. A melhoria da sen
Publicado em: 2008
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7. Design of an optical transceiver for free space optical digital communication. / Projeto de um transceptor óptico para comunicação digital em espaço livre.
Os sistemas de comunicação óptica por espaço livre, comumente denominados sistemas FSO (Free Space Optics), servem para estabelecer enlaces de comunicação do tipo wireless, ponto-a-ponto, a uma elevada taxa de dados e com alcances que podem variar de algumas centenas de metros a alguns quilômetros. O interesse pela tecnologia FSO tem sido estimulado p
Publicado em: 2007
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8. Desenvolvimento do cristal semicondutor de Brometo de Tálio para aplicações como detector de radiação e fotodetector / Development of TIBr semiconductor crystal for applications as radiation detector and photodetector
In this work, TlBr crystals were grown by the Bridgman method from zone melted materials. The influence of the purification efficiency and the crystalline surface quality on the crystal were studied, evaluating its performance as a radiation detector. Due to significant improvement in the purification and crystals growth, good results have been obtained for
Publicado em: 2006
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9. INFLUÊNCIA DA CONDENSAÇÃO CAPILAR NA FRICÇÃO EM NANO ESCALA / INFLUENCE OF CAPILLARY CONDENSATION IN NANOSCALE FRICTION
In this work, the procedures developed to the calibration of the AFM photodetector and cantilevers for lateral force measurements in our AFM is presented. A Matlab code that controls the microscope allows the study of the influence of the normal force on the lateral one. A second Matlab code was developed in order to study the adhesion forces in an automated
Publicado em: 2005
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10. Nova tecnica de processamento de sinais no dominio do tempo de giroscopios interferometricos de Sagnac a fibra optica
This work focuses on the study of a new time domain signal processing technique of Sagnac interferometric fiber optic gyroscopes. The technique consists in demodulating the output signal of the interferometer to obtain the rotation rate W and to monitor both the optical phase modulation depth m f and the incident power level 0 P , by measuring the dc value a
Publicado em: 2001
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11. An on-chip thin film photodetector for the quantification of DNA probes and targets in microarrays
A flat microdevice which incorporates a thin-film amorphous silicon (a-Si:H) photodetector with an upper layer of functionalized SiO2 is used to quantify the density of both immobilized and hybridized DNA oligonucleotides labeled with a fluorophore. The device is based on the photoconductivity of hydrogenated amorphous silicon in a coplanar electrode configu
Oxford University Press.
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12. Control of sarcomere length in skinned muscle fibres of Rana temporaria during mechanical transients.
A new technique is described for high-speed measurement of striation spacing of single skinned muscle fibres. A galvanometer mirror directs helium-neon laser light on to the muscle fibre at a variable angle. Light diffracted by the cross-striations is collected by a position-sensitive photodetector. The incident angle necessary to centre the diffracted light