Dielectric Relaxation
Mostrando 1-12 de 46 artigos, teses e dissertações.
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1. Ferrimagnetic to paramagnetic transition and dielectric relaxation in Ni1-xZnxFe2O4 ferrites
Abstract The spinel ferrite system Ni1-xZnxFe2O4 (x=0-0.7, Δx=0.1) was prepared by wet chemical co-precipitation method using sulfates of respective metal ions. The electrical resistivity and dielectric properties of the prepared samples have been studied as a function of temperature, frequency, and Zn content (x). The DC resistivity (ϱ) was measured in th
Cerâmica. Publicado em: 2021-06
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2. Design of Ground Penetrating Radar Antenna for Detecting Soil Contamination at L-band Frequencies
Abstract Maintenance of oil pipelines is an issue of great concern for oil companies. Soil contamination is caused by oil leaks from underground pipelines. Ground penetrating radar (GPR) is a rapid and relatively inexpensive technique used for locating and characterizing soil contaminated sites without producing fractures and causing further migration of con
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2017-09
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3. Synthesis, Characterization and Electromagnetic Properties of SnO-coated FeNi Alloy Nanocapsules
SnO-coated FeNi alloy nanocapsules have been synthesized by an arc-discharge method. High-resolution transmission electron microscopy and x-ray photoelectron spectroscopy analysis show that the nanocapsules have a shell/core structure with FeNi alloy nanoparticles as the core and amorphous SnO as the shell. Dielectric relaxation of SnO shell and the interfac
Mat. Res.. Publicado em: 10/10/2016
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4. Microwave Absorbing Properties of NiFe2O4 Nanosheets Synthesized Via a Simple Surfactant-Assisted Solution Route
NiFe2O4 nanosheets have been synthesized via a simple surfactant-assisted solution route, which are confirmed by X-ray powder diffraction, scanning electron microscopy and transmission electron microscopy. The NiFe2O4 sample exhibits the sheet-like structure, with width varying from 200 to 800 nm and thickness ranging from 20 to 60 nm. The electromagnetic pr
Mat. Res.. Publicado em: 25/08/2016
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5. Impedance and Modulus Spectroscopy Characterization of Tb modified Bi0.8A0.1Pb0.1Fe0.9Ti0.1O3 Ceramics
In this paper we present the impedance spectroscopy of ternary solid solutions of BiFeO3, TbFeO3 and PbTiO3, prepared by solid-state reaction method. The preliminary structural studies were carried out by x-ray diffraction technique, showing the formation of polycrystalline sample with ABO3 type of perovskite structure with hexagonal symmetry for Bi0.8Tb0.1P
Mat. Res.. Publicado em: 16/02/2016
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6. Hydrothermal Synthesis of Three-dimensional Butterfly-like Ni Architectures as Microwave Absorbers
AbstractThree-dimensional butterfly-like Ni architectures were fabricated by a surfactant-assisted hydrothermal method. The Ni architectures, with lengths of about 20 μm and widths of 4-6 μm, were assembled from tens of Ni nanorods with the averaged diameter of about 200 nm. The Ni nanorods were coated by oxide shells. The saturation magnetization of the N
Mat. Res.. Publicado em: 2015-10
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7. Large Scale Synthesis of Superparamagnetic Face-centered Cubic Co/C Nanocapsules by a Facile Hydrothermal Method and their Microwave Absorbing Properties
A large scale direct hydrothermal method has been used to prepare face-centered cubic (FCC) Co/C nanocapsules with a core of FCC-Co nanoparticles and a shell of amorphous C. The size distribution is 5-20 nm. The TB of FCC-Co/C nanocapsules is determined as 85 K, indicating that FCC-Co/C nanocapsules are superparamagnetic at 300 K. For FCC-Co/C nanocapsules-p
Mat. Res.. Publicado em: 2015-08
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8. Compatibilization efficiency of carboxylated nitrile rubber and epoxy pre-polymer in nitrile/acrylic rubber blends
An investigation has been made of the effects from a compatibilizer, viz. carboxylated nitrile rubber (XNBR), on several properties of nitrile rubber (NBR) and acrylic rubber (ACM) blends, including curing characteristics, mechanical, dynamic mechanical and dielectric properties. The presence of XNBR until 10 phr resulted in an improvement of the ultimate te
Polímeros. Publicado em: 05/04/2013
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9. The influence of the industrial processing on the degradation of poly(hidroxybutyrate) - PHB
PHB was characterized after different industrial processes by Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), Melt Flow Index (MFI), Complex Dielectric Relaxation (CDR) and Size Exclusion Chromatography (SEC). Some properties of PHB were investigated before and after processing, in order to understand how temperature
Mat. Res.. Publicado em: 18/12/2012
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10. PROPRIEDADES VIBRACIONAIS E DIELÉTRICAS DA MULITA Bi2Mn4O10 / VIBRATIONAL PROPERTIES AND DIELECTRIC OF MULITA Bi2Mn4O10
In this work we investigated the vibrational properties of ceramics Bi2Mn4O10 (BMO) at room temperature by the Raman and Infrared spectroscopies, the phonons were classified by FG matrix method of Wilson. The dielectric properties of the material, in turn, were studied using the impedance spectroscopy in a range of 22 C to 275 C. Furthermore, static atomisti
Publicado em: 2010
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11. SÃntese e estudo das propriedades dielÃtricas dos compÃsitos cerÃmicos [(Cr3/8Fe5/8)2O3 â CRFO][X] â [CaTiO3 - CTO][1-x] e [BiFeO3 - BFO][x] - [CaTiO3-CTO][1-x] / Synthesis and study of dielectric properties of ceramic composites [(Cr3/8Fe5/8)2O3 â CRFO][X] â [CaTiO3 - CTO][1-x] e [BiFeO3 - BFO][x] - [CaTiO3-CTO][1-x]
Neste trabalho, foi realizada a sÃntese das fases CaTiO3 (CTO), (Cr3/8Fe5/8)2O3 (CRFO) e BiFeO3 (BFO) e duas sÃries de compÃsitos cerÃmicos entre o CTO e as outras duas fases, variando-se a concentraÃÃo das fases. O processo de sÃntese foi via moagem mecÃnica e reaÃÃo de estado sÃlido. ApÃs a calcinaÃÃo, as amostras foram prensadas na forma de
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 20/02/2009
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12. Structural and dielectric properties of ZrO2 added (Na1/2Bi1/2)TiO3 ceramic
Polycrystalline samples of ZrO2 added (Na1/2Bi1/2)TiO3 were prepared using high-temperature solid-state reaction method at 1050ºC and subsequent sintering at 1090ºC in air atmosphere. Rietveld analyses of XRD data indicated the formation of a single-phase hexagonal structure with R3c symmetry. Dielectric studies revealed the relaxor behaviour. The addition
Brazilian Journal of Physics. Publicado em: 2009-06