Electromagnetic Theory
Mostrando 13-24 de 68 artigos, teses e dissertações.
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13. Aplicação da técnica de elipsometria de emissão para caracterização de materiais luminescentes
In this work we demonstrated the potential of the emission ellipsometry in the scope of the Stokes theory for electromagnetic field to the photophysics study of luminescent materials, in addition we introduce a new methodology using an achromatic quarter-wave plate. Moreover, the use of linearly polarized light allowed "selectively" the study of various phot
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 07/02/2012
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14. Um estudo sobre tensões induzidas por descargas atmosféricas em linhas de transmissão
The study of lightning and the resulting induced voltages is very important in the process of designing of transmission lines. In this work it will be presented problems that can be caused by such phenomenon in electrical systems, as a consequence of these voltages peaks. A analysis of the characterization of atmospheric discharge is performed in order to un
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 02/09/2011
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15. Expansão de campos eletromagnéticos arbitrários em termos de funções de onda vetoriais / Expansion of arbitrary electromagnetic fields in terms of vector spherical wave functons
Desde 1908, quando Mie apresentou expressões analíticas para os campos espalhados por uma partícula esférica sob incidência de uma onda eletromagnética plana, generalizações para esta expansão têm se mostrado incompletas. Isto se deve à presença de certos termos com dependência radial nos coe cientes de forma do feixe quando expandido em termos
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 12/11/2010
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16. Análise fractal da vascularização da membrana corioalantóide de embriões de codornas japonesas (Coturnix japonica submetidas a campo eletromagnético de 60 Hz.
The formation of vascular network is governed mainly by two processes, vasculogenesis and angiogenesis. In vasculogenesis, the angioblastic which are the precursors of endothelial cells arising in germ layer (mesoderm) of the yolk sac (outside the embryo body). These angioblastic organize themselves to form blood islands, differing in blood vessels where the
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 30/06/2010
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17. Is it possible to accommodate massive photons in the framework of a gauge-invariant electrodynamics?
The construction of an alternative electromagnetic theory that preserves Lorentz and gauge symmetries, is considered. We start off by building up Maxwell electrodynamics in (3+1)D from the assumption that the associated Lagrangian is a gauge- invariant functional that depends on the electron and photon fields and their first derivatives only. In this scenari
Brazilian Journal of Physics. Publicado em: 2010-09
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18. Dificultades de los estudiantes universitarios en el aprendizaje de la inducción electromagnética
The work presented deals with the ideas of first-year Engineering students and third year Physics students about the theory of electromagnetic induction (EI). In this investigation we analyse that part of the theory of EI relating to Faraday's law which comes within the basic analysis of induction phenomena for introductory physics courses within classical p
Revista Brasileira de Ensino de Física. Publicado em: 2010-03
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19. Espalhamento de ondas eletromagnéticas por esferas e cilindros magnéticos: confinamento e transporte de ondas no limite de pequenas partículas e independência da energia armazenada com relação à forma do centro espalhador / Electromagnetic wave scattering by magnetic spheres and cylinders: waves confinement and transport in the small particle limit and independence of the stored energy with respect to the shape of the scatterer
O espalhamento eletromagnético por uma esfera com propriedades ópticas e raio arbitrários, conhecido como espalhamento de Lorenz-Mie, ou por um cilindro circular infinito, pode ser resolvido analiticamente e é comumente tratado dentro da abordagem de espalhadores dielétricos. Na região óptica, tanto meio circundante quanto partícula espalhadora possu
Publicado em: 2010
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20. Antenas de microfita com patch supercondutor a 212 K
This work has as main objective to study the application of microstrip antennas with patch and use of superconducting arrays of planar and linear phase. Was presented a study of the main theories that explain clearly the superconductivity. The BCS theory, Equations of London and the Two Fluid Model are theories that supported the implementation of the superc
Publicado em: 2010
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21. A historical study of the evolution of vector potential in classical electromagnetic theory / Um estudo histórico da evolução do conceito de potencial vetor no eletromagnetismo clássico
Currently the vector potential generally is considered in the classical electromagnetic theory as an artifice for the calculation of the electric and magnetic fields and without a clear physical meaning. However, when it was proposed in the mid-nineteenth century, it used to have a clear physical meaning and played a central role for Faraday, Maxwell and oth
Publicado em: 2009
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22. Two-component spinor formulation of the maxwell theory / Formulação em termos de espinores de duas componentes da teoria eletromagnética clássica
In this work the two-component spinor formulation of the classical theory of electromagnetic fields is presented. In particular, we obtain explicitly the wave equa-tion for photons of both helicities. For this purpose, we present first the formulation of the theory in Minkowski spacetime together with the homomorphism between SL(2;C) and the restricted Loren
Publicado em: 2009
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23. Lorente symmetry breaking and chern-simons term in (3+1) dimensions / Quebra da simetria de Lorentz e o termo de Chern-Simons em (3+1) dimensões
In this dissertation, we studied the Chern-Simons model in the gauge and the gravitation theories. So, we study the problem of fermions interacting, in a first moment, with a electromagnetic field and in a second moment, with a gravitational field. We introduced in the interaction lagragian, for both cases, a background field which break the Lorentz symmetry
Publicado em: 2009
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24. Introdução de tópicos de física moderna e contemporânea no ensino médio por meio do estudo de ondas eletromagnéticas
Nowadays it is necessary, urgent and inevitable, to introduce topics on modern and contemporary Physics in Brazilian schools. It is unacceptable that in the 21st century, our students, in the highlight of the use of technology promoted by modern Physics, have no background of this fascinating and wide area of Physics. In this research we propose the introduc
Publicado em: 2009