Dielectric Medium
Mostrando 1-12 de 33 artigos, teses e dissertações.
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1. Side Lobe Reduction in an X - Band Horn Antenna Loaded by a Wire Medium
ABSTRACT: Through electromagnetic simulation, the present work reports on a comparative study of the enhanced radiation properties of a standard X-band horn antenna loaded by a wire medium. Acting as an artificial dielectric, the wire medium consists of an array of parallel metallic wires installed into the antenna with the wires oriented in the direction of
J. Aerosp. Technol. Manag.. Publicado em: 2015-09
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2. Long Period Bragg Grating in Coaxial Transmission Lines
This work shows the utilization of a coaxial cable for the fabrication of a long period Bragg grating. The grating is fabricated removing the dielectric in short pieces of the cable so that the discontinuities account for the variation in the medium refractive index. Simulated and experimental results of the grating resonances are shown as a function of the
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2015-06
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3. Avaliação do comportamento dielétrico de isoladores de distribuição de média tensão frente a impulsos atmosféricos com formas de onda não normalizadas / Analysis of the dielectric behavior of medium voltage insulators under non-standard lightning impulse voltages
As linhas de distribuição de energia estão freqüentemente expostas a sobretensões causadas por descargas atmosféricas diretas e indiretas. As formas de onda dessas sobretensões têm uma faixa de variação muito ampla e podem diferir bastante do impulso atmosférico normalizado utilizado em ensaios para verificação da adequação dos projetos das is
Publicado em: 2011
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4. 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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5. 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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6. ESTUDO TEÓRICO DE ESTRUTURA, PROPRIEDADES E REATIVIDADE DE TRIGLICERÍDEOS E ÉSTERES DE ÁCIDOS GRAXOS ENVOLVIDOS NA PRODUÇÃO E COMPOSIÇÃO DO BIODIESEL
The present work aims the study of structural and thermodynamic properties for process involving triglycerides (TG), fatty acid esters (EAG) and biodiesel through theoretical and chemometrical methodologies. The study of the transesterification reaction of triglycerides (TG) using cyclodextrin (CD) as a potential catalyst were also carried out. Initially, th
Publicado em: 2010
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7. Thermodynamic modeling of aqueous two phase systems containing salts and polymers. / Modelagem termodinâmica de sistemas aquosos bifásicos contendo sais e polímeros.
The thermodynamic modeling of phase equilibrium in aqueous two phase systems containing the neutral polymer poly(ethylene glycol) and a salt was studied in this work. The implemented model is based on the Pitzer equation for electrolytes solutions, modified in order to account for the influence of polymer properties in both the medium dielectric constant and
Publicado em: 2008
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8. Electron Cyclotron Emission in the TCABR Tokamak: An Experimental Study. / "Emissão Eletrociclotrônica no Tokamak TCABR: Um Estudo Experimental"
In this work, an experimental study of the Electron Cyclotron Emission (ECE) in the TCABR Tokamak, is described. An ECE sweeping heterodyne radiometer, operating in the 50-85 GHz frequency range, was installed, calibrated and used to detect ECE radiation in the second harmonic extraordinary mode from thermal plasma discharges. The noise temperature, amplitud
Publicado em: 2005
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9. Mathematical modeling of electro-rotation spectra of small particles in liquid solutions: Application to human erythrocyte aggregates
Electro-rotation can be used to determine the dielectric properties of cells, as well as to observe dynamic changes in both dielectric and morphological properties. Suspended biological cells and particles respond to alternating-field polarization by moving, deforming or rotating. While in linearly polarized alternating fields the particles are oriented alon
Brazilian Journal of Medical and Biological Research. Publicado em: 2004-02
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10. Medidas do perfil da permissividade eletrica em interfaces solido-liquido, usando microscopia de força atomica
When immersed in water, several surfaces are electrically charged. Therefore, repulsive and attractive forces between the tip and the sample are detected during image generation by atomic force microscopy in aqueous medium. In the last decades repulsive forces have been attributed to electrostatic interactions, while attractive forces have been ascribed to v
Publicado em: 2001
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11. Emissão, propagação e amplificação da radiação quilométrica das auroras nas subcavidades aurorais
The present work investigates the propagation and amplification of electromagnetic waves in a plasma localized in the vicinity of the geomagnetic poles, at heights not much greater than three times the Earth s radius. The phenomena studied is known as the Aurorai Kilometric Radiation (AKR), the strongest of the various types of emission that can occur as a c
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 2001
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12. Evaluacion termica, mecanica y electrica de materiales compuestos cordierita-mullita
Commercially available cordierite and mullite powders were used to obtain cordierite and cordierite-30wt% mullite materials by attrition milling, uniaxial pressing and sintering. Cordierite powders were the coarse (D50 = 1.82 mum), medium (D50 = 0.9 mum) and fine (D50 = 0.45 mum) single granulometric fractions and binary mixtures of them. Mullite powder empl
Materials Research. Publicado em: 2000-10