Dielectric Devices
Mostrando 13-24 de 38 artigos, teses e dissertações.
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13. Influência da condutividade e permissividade do solo em função da frequência no cálculo da impedância longitudinal e admitância transversal de linhas aéreas de transmissão / Influence of earth´s conductivity and permittivity frequency dependence on longitudinal impedance and transversal admittance transmission line´s parameters calculation
This thesis aims to propose more accurate models for calculating the electrical parameters of overhead power transmission lines. The influence of earth s conductivity and permittivity frequency dependence is evaluated when calculating transversal and longitudinal transmission lines parameters in the frequency range 0 to 2 MHz. This frequency range covers the
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 22/04/2010
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14. MICROWAVE DEVICES USING HIGH DIELECTRIC CONSTANT FILMS / DISPOSITIVOS DE MICROONDAS UTILIZANDO FILMES DE ALTA CONSTANTE DIELÉTRICA
The growing demand for portable devices with more reduced size and weight has stimulated the search for materials with high dielectric constant and low losses in the microwave frequency range allowing circuit integration and miniaturization. In this work, a theoretical and experimental study of the use of high dielectric constant films in the fabrication of
Publicado em: 2010
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15. Obtenção de uma porcelana dielétrica a partir de matérias-primas do Rio Grande do Norte
The dielectric porcelain is usually obtained by mixing various raw materials proportions and is used in the production of electronic equipment for various applications, from capacitors of high and low Power to insulators for low, medium, high and extra high voltage, which are used in distribution lines and transmission of electricity.This work was directed t
Publicado em: 2010
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16. Microlasers de cavidades estadio aplicados a detecção nanovolumetrica / Stadium cavities microlasers applied to the nanovolumetric detection
This work presents the development of resonant cavities based on chaotic billiard geometries built with semiconductor active optical medium for sensing applications. In spite of the classically chaotic behavior of the stadium, the quantum description of the problem in the semi-classical limit shows unexpected accumulations of the density of probability on cl
Publicado em: 2010
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17. Investigation of structural, electronic and magnetica properties of Ca2-xLaxFelrO6, Sr2-xLaxFelrO6 e TbMnO3 oxides / Investigação as propriedades estruturais, eletronicas e magneticas dos oxidos Ca2-xLaxFelrO6, Sr2-xLaxFelrO6 e TbMnO3
For many decades the transition metal oxides are subject of great scientific interest because of the wide variety of interesting physical properties and their potential technological applications. More recently, for example, oxides of transition metals with multiferroic properties have been considered as potential magneto-electronic devices. Many transition
Publicado em: 2010
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18. Propagação não linear de pulsos em estruturas 1D com band gap fotonico / Nonlinear pulse propagation in one-dimensional photonic band gap structures
The interaction of ultrashort optical pulses with photonic band gap materials has been studied by considering light propagation through one-dimensional photonic band gap structures, composed of a periodic multilayer stack of dielectric materials whose unitary cell consists of a pair of layers with different refractive indices n1and n2, respectively. One of t
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 17/08/2009
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19. Evaluation and modelling of integral capacitors produced by interdigitated comb electrodes
Integral capacitors (IC) of one or two-layer printed wiring board (PWB) circuits were produced using comb electrodes fixtures and dielectric composites as the inter-electrode material. ICs were fabricated at laboratory scale, using copper comb electrodes and BaTiO3-epoxy composite materials deposited on a glass-Epoxy FR4 board. They were experimentally teste
Materials Research. Publicado em: 2008-12
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20. Co2Z hexaferrite obtained by the citrate precursor method in an inert atmosphere
Nanoparticles of Co2Z hexaferrite were synthesized by the citrate sol-gel process under an inert atmosphere, then thermally analyzed by Thermogravimetric and Differential Thermal Analysis and characterized by X-ray Diffraction, Scanning Electron Microscopy, Atomic Force Microscopy, X-ray Fluorescence and Vibration Sample Magnetometry. Z-type barium hexaferri
Matéria (Rio de Janeiro). Publicado em: 2008-06
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21. Estudo do efeito de elevação atípica da transcondutância na região linear de polarização em dispositivos SOI nMOSFETS ultra-submicrométricos. / Study of gate induced floating body effect in the linear bias region in deep submicrometer nMOSFETs devices.
This work presents the study of the Gate Induced Floating Body Effect (GIFBE) that occurs in the SOI MOSFET technology. This study has been performed based on experimental results and on numerical simulations, which were an essential auxiliary tool to obtain a physical insight of this effect. Besides the contribution on the physical explanation of this pheno
Publicado em: 2008
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22. Isolantes de porta com altas constantes dieletricas (High K) para tecnologia MOS / High K gate insulators for MOS technology
High k insulators for the next generation (sub-32 nm CMOS (complementary metaloxide-semiconductor) technology), such as titanium oxide (TiOx), titanium oxynitride (TiOxNy), titanium-aluminum oxynitride (AlxTiwOyNz), titanium-aluminum nitride (AlxTiwNz) and titanium-aluminum oxide (AlxTiwOy), have been obtained by Ti or Ti/Al e-beam evaporation, with addition
Publicado em: 2008
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23. Estudo das propriedades estruturais e elÃtricas das granadas ferrimagnÃticas GdIGXYIG1-X e suas aplicaÃÃes em componentes de microondas. / Study of the strutural and electric properties of garnets ferrimagnetc GdIGXYIG1-X and its aplications in componentes of microwaves.
Due to a fast progress in the development of communication systems, the dielectric and magnetic ceramics (ferrites) have become attractive to be used in devices. Although the ferrites of the spinel type were the first material used in the microwave range, garnets have smaller dielectric losses and, therefore, are chosen for many applications. High demands fo
Publicado em: 2008
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24. Estudo de camadas dielétricas para aplicação em capacitores MOS. / Study of dielectric layers for MOS capacitors.
Silicon oxynitride films obtained by the PECVD technique from N2O+SiH4+He gaseous mixtures, at 320°C, with different deposition pressure and RF power were studied intending to improve the interface quality with Si, decreasing the effective charge density and the interface state density in order to utilize them in MOS semiconductor devices. The results showe
Publicado em: 2007