Magnetic Phenomena
Mostrando 1-12 de 79 artigos, teses e dissertações.
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1. Cation Vacancies in NiFe2O4 During Heat Treatments at High Temperatures: Structural, Morphological and Magnetic Characterization
Nickel ferrite (NiFe2O4) was synthesized by mixing stoichiometric amounts of α-Fe2O3 and NiO using mechanical milling and heat treatments at high temperatures. The physical characterization of the samples was carried out using X-ray diffraction, infrared and Raman spectroscopies, Mössbauer spectrometry, magnetization measurements, scanning electron microsc
Mat. Res.. Publicado em: 20/12/2019
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2. Uma andorinha só não faz verão: 160 anos do legado de Richard Carrington
Resumo No dia 1° de setembro de 1859, o astrônomo britânico Richard Carrington observou um comportamento anômalo no Sol. Aproximadamente 17 horas depois, efeitos magnéticos de escalas globais foram observados na Terra: auroras boreais e austrais em regiões de baixas latitudes, e falhas em equipamentos telegráficos na Europa e América do Norte. Hoje,
Rev. Bras. Ensino Fís.. Publicado em: 25/11/2019
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3. Influence of graphene oxide on ‘in situ’ preparation of nanocomposites with polyvinyl butyral
ABSTRACT In this work, polyvinyl butyral (PVB) nanocomposites reinforced with 0.5 to 2.5 wt% of graphene oxide (GO) were synthesized via ‘in situ’ polymerization. PVB was obtained by condensation of hydroxyl groups of polyvinyl alcohol (PVA) with butyraldehyde (BU) Thermogravimetric analyzes (TGA) showed the increase in the thermal conductivity of the na
Matéria (Rio J.). Publicado em: 16/09/2019
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4. Comparing the Schrödinger and Dirac Descriptions of an Electron in a Uniform Magnetic Field
Abstract In this article we present a detailed description, using ladder operators, of an electron in a uniform magnetic field evolving under the Schrödinger equation. We go on to describe the same physical system in terms of relativistic quantum mechanics using the Dirac equation and to compare the two models in detail. The main differences between these t
Rev. Bras. Ensino Fís.. Publicado em: 11/06/2018
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5. New trends in plasmonic (bio)sensing
Abstract The strong enhancement and localization of electromagnetic field in plasmonic systems have found applications in many areas, which include sensing and biosensing. In this paper, an overview will be provided of the use of plasmonic phenomena in sensors and biosensors with emphasis on two main topics. The first is related to possible ways to enhance t
An. Acad. Bras. Ciênc.. Publicado em: 2018
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6. Effects of a buried magnetic field on cranial bone reconstruction in rats
ABSTRACT The understanding of bone repair phenomena is a fundamental part of dentistry and maxillofacial surgery. Objective The present study aimed to evaluate the influence of buried magnetic field stimulation on bone repair in rat calvaria after reconstruction with autogenous bone grafts, synthetic powdered hydroxyapatite, or allogeneic cartilage grafts,
J. Appl. Oral Sci.. Publicado em: 2016-04
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7. Estudo de propriedades petrofísicas de rochas sedimentares por Ressonância Magnética Nuclear / Petrophysical properties study of sedimentary rocks by Nuclear Magnetic Resonance
The Nuclear Magnetic Resonance (NMR) technique is one of the most versatile techniques for scientific research, specially for the study of dynamics, structure and conformational of materials. In particular, its application in oil science is one of its first routine applications. Methodologies developed specifically to match this scientific community proved t
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 28/05/2012
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8. ANALISE E PROJETO DO CONVERSOR BUCK INTERCALADO PARA ALIMENTAÇÃO DE LÂMPADAS DE DESCARGA EM ALTA PRESSÃO DE ALTA POTÊNCIA / INTERLEAVED BUCK CONVERTER ANALYSIS FOR HIGH POWER HIGH INTENSITY DISCHARGE LAMPS SUPPLYING
This work presents a detailed analysis about the interleaved buck converter applied to electronic ballasts to supply high power HID lamps, assuming the input voltage as a PFC stage output. As the output capacitor has a maximum value to be applied in parallel with the lamp, parallel operated converters are a suitable choice because the output current ripple c
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 29/02/2012
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9. Structure and dynamics of poly(9,9-dioctylfluoren-2,7-co-benzothiadiazole) (F8BT) and correlations with its electrical properties / Estrutura e dinâmica molecular do poly (9,9-dioctylfluoren-2,7-diyl-co-benzothiadiazole) (F8BT) e correlações com suas propriedades elétricas.
The PHD project has two main goals. The first one is specifically related to investigations on molecular dynamics, structural conformations and packing of polyfluorene-based polymers. For this purpose, Wide Angle X-Ray Diffraction (WAXD), Solid-State Nuclear Magnetic Resonance (NMR) and Dynamical-Mechanical Thermal Analysis (DMTA) are being used as the main
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 16/09/2011
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10. Implementações sequencial e paralela de um novo algoritmo para a simulação de elementos e compostos magnéticos
The magnetic phenomena are widely used in many devices, such as electronic, data storage and telecommunications devices. The understanding of this phenomenon is therefore of great interest to support the improvement and development of new technologies. To better understand the magnetic phenomena, it is essential to study interactions at nano scale. When magn
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 25/02/2011
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11. Contribution of adiabatic phases to noncyclic evolution
We show that the difference of adiabatic phases, that are basis-dependent, in noncyclic evolution of non-degenerate quantum systems have to be taken into account to give the correct interference result in the calculation of physical quantities in states that are a superposition of instantaneous eigenstates of energy. To verify the contribution of those adiab
Brazilian Journal of Physics. Publicado em: 2010-06
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12. Comportamento crítico do processo de contato aperiódico: simulações e grupo de renormalização / Critical behavior of the aperiodic contact process: simulation and renormalization-group
Utilizamos um formalismo de operadores e a técnica de grupo de renormalizacao de Dasgupta, Ma e Hu para analisar o efeito de distribuições inomogêneas dos parâmetros sobre o comportamento crítico de um modelo estocástico simples. O processo de contato em uma dimensão constitui talvez o modelo mais simples que apresenta uma transição de fase para um
Publicado em: 2010