Dielectric Materials
Mostrando 13-24 de 86 artigos, teses e dissertações.
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13. Electromagnetic Characterization of Aircraft Composite Materials and its Effects on the Antenna Performance
Abstract This paper presents an electromagnetic characterization of aircraft composite materials, as well as numerical and experimental analyses of its effects on the antenna performance. Two uncalibrated S-parameters characterization methods have been applied for retrieving the complex electrical permittivity in the L- and C-band, namely: Air-region method
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2017-03
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14. Non-resonant Permittivity Measurement Methods
Abstract The measurement of the dielectric properties of materials has been applied in non-destructive tests, humidity measurement, soil analysis and even cancer detection. The methods have been developed for over 70 years based on the interaction of the electromagnetic waves with the material under test. This work presents a general model of scattering para
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2017-03
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15. Electrical Conductivity in the KDP, ADP, and K1-x(NH4)xH2PO4 Crystals
Impedance Spectroscopy was performed to examine the electrical conductivity on KH2PO4 KDP, (NH4)H2PO4 ADP and K1-x(NH4)xH2PO4 (x = 0.076, 0.118, 0.357, 0.857, 0.942) crystals with increasing temperature. They were grown by solvent evaporation method. Zview simulation software was used to theoretically fit electrical conductivity results as a function of freq
Mat. Res.. Publicado em: 23/02/2017
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16. Studying the electrical, thermal, and photocatalytic activity of nanocomposite of polypyrrole with the photoadduct of K3[Fe(CN)6] and diethylenetriamine
Abstract The present work reports the synthesis of nanocomposite of polypyrrole with [Fe(CN)3(dien)].H2O photoadduct via in-situ oxidative chemical polymerisation. Photoadduct was synthesised by irradiating an equimolar mixture of K3[Fe(CN)6] and diethylenetriamine (dien) using Osram photo lamp. The successful synthesis of photoadduct was proved by Elemental
Mat. Res.. Publicado em: 25/07/2016
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17. Effects of La2O3-Doping and Sintering Temperature on the Dielectric Properties of BaSrTiO3 Ceramics
Using BaCO3, SrCO3 and TiO2, et al as crude materials, La2O3 as dopant, Ba0.8Sr0.2TiO3 (BST) Ceramics of perovskite structure were prepared by solid state reaction method. We investigated the effects of La2O3-doping and sintering temperature on the dielectric properties of BaSrTiO3 ceramics. The experiment results show that: The amount of La2O3 can increase
Mat. Res.. Publicado em: 15/03/2016
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18. Study of the Influence of Variation in Distances Between Electrodes in Spectral DBD Plasma Excitation
Dielectric Barrier Discharge (DBD) is a promising technique for producing plasma in atmospheric pressure and is gaining emphasis in several areas, especially in the biomedical and textile industries, among other. This is due to the fact that this plasma does not reach high temperatures, enabling its use on thermally sensitive materials. However, there is sti
Mat. Res.. Publicado em: 05/02/2016
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19. Dielectric Behavior of Alginate-Based Hydrogel Containing Neomycin-Loaded Lipid Nanovesicles under Influence of Electrical Potentials
Dielectric characterization has been applied as a convenient tool for evaluation of transport and polarization mechanisms in soft materials. In this work, we have explored the study of charge transport mechanisms in alginate hydrogel containing neomycin-loaded liposomes. For comparison, drug release kinetic was evaluated by using UV-Vis spectrophotometry and
J. Braz. Chem. Soc.. Publicado em: 2016-01
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20. An Investigation of Ac Impedance and Dielectric Spectroscopic Properties of Conducting Chitosan-silane Crosslinked-poly (Vinyl Alcohol) Blended Films
The films of chitosan (CS)-silane crosslinked-poly(vinyl alcohol) (PVA) with different weight % were prepared. The effect on conductivity of CS/PVA blended films due to change in the concentration of PVA and temperature was investigated by impedance spectroscopy and showed good conductance properties. The complex impedance plots revealed single semicircular
Mat. Res.. Publicado em: 03/11/2015
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21. Complex permeability and permittivity variation of radar absorbing materials based on MnZn ferrite in microwave frequencies
The complex dielectric permittivity (ε) and magnetic permeability (µ) of Radar Absorbing Materials (RAM) based on magnetic particles (MnZn ferrite particles) embedded in a dielectric matrix (silicon rubber) have been studied in the frequency range of 2 to 18 GHz. The relative permeability and permittivity of MnZn ferrite-silicon composites for various mass
Mat. Res.. Publicado em: 21/05/2013
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22. ObtenÃÃo das cerÃmicas dielÃtricas BiTRWO6 (TR = Y, Gd ou Nd) por radiaÃÃo de micro-ondas e sua aplicaÃÃo em dispositivos eletrÃnicos / Obtaining Of Ceramic Dielectric BiTRWO6 (Tr = Y, Gd Or Nd) By Microwave Radiation And Its Application In Electronic Devices
The mixture heat of the metal oxides may promote the formation of ceramic materials, depending on their dielectric properties and its crystalline structure may be used with electronic components for a variety of functions in electrical circuits. Heating method is directly related to the material properties. This work aims to use a commercial microwave oven m
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 20/08/2012
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23. Aplicação de novos materiais em transistores de efeito de campo ferroelétricos
In this work, we investigated the electrical properties of the polyelectrolyte PSS in its sodium form (PSS-Na, Polystyrene sulfonic in the sodium form) and acid form (PSS-H, polystyrene sulfonic in the acid form) and also doped with Fe3+ for application in Ferroelectric Field Effect Transistors (Fe-FET). The PSS-Na was acquired from Aldrich and PSS-H was obt
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 27/07/2012
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24. Preparação e Caracterização de Pós e Filmes De PbTiO3 obtidos pelo Método Pechini / Preparation and Characterization of Powders and Films From PbTiO3 obtained by Pechini method
Non-crystalline materials, commonly referred to as amorphous materials have attracted great interest in engineering and technology. This is due mainly to its photoluminescent properties at room temperature around 25 C. The aim of this study was the Pechini method in order to obtain ceramic powders and amorphous films of amorphous lead titanate. The lead tita
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 29/02/2012