Percolation Theory
Mostrando 1-12 de 18 artigos, teses e dissertações.
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1. Estimativa de expoentes críticos em Percolação
In Percolation Theory, functions like the probability that a given site belongs to the infinite cluster, average size of clusters, etc. are described through power laws and critical exponents. This dissertation uses a method called Finite Size Scaling to provide a estimative of those exponents. The dissertation is divided in four parts. The first one briefly
Publicado em: 2010
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2. Implantação iônica de baixa energia em polímero para desenvolvimento de camadas compósitas nanoestruturadas condutoras litografáveis. / Low energy ion implantation into polymers to develop conductive composite layers for lithography.
Electronics using polymers instead of silicon is a recent research area with promising economic perspectives. Polymer with metallic particles composites presents interesting electrical, magnetic and optical properties and they have been produced by a broad variety of techniques. Metal ion implantation using plasma is one of the used methods to obtain conduct
Publicado em: 2010
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3. Alignment of carbon nanotubes in epoxy matrix by electric field / Influência nas propriedades elétricas devido ao alinhamento de nanotubos de carbono em matriz epóxi utilizando campo elétrico
Nanotubos de paredes múltiplas (NCPM) dispersos em matriz epóxi (DGEBA) foram alinhados com o auxilio de um campo elétrico senoidal, de amplitude de 300 V/cm e freqüência de 1 kHz, durante a cura dos nanocompósitos. Foram fabricados nanocompósitos submetidos ao campo elétrico (nanotubos alinhados) e amostras curadas sem a presença do campo (com nano
Publicado em: 2010
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4. Análise de modelos geológicos utilizando percolação dinâmica
In the present study we elaborated algorithms by using concepts from percolation theory which analyze the connectivity conditions in geological models of petroleum reservoirs. From the petrophysical parameters such as permeability, porosity, transmittivity and others, which may be generated by any statistical process, it is possible to determine the portion
Publicado em: 2009
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5. Estudo de Fractalidade e Evolução Dinâmica de Sistemas Complexos
In this work, the study of some complex systems is done with use of two distinct procedures. In the first part, we have studied the usage of Wavelet transform on analysis and characterization of (multi)fractal time series. We have test the reliability of Wavelet Transform Modulus Maxima method (WTMM) in respect to the multifractal formalism, trough the calcu
Publicado em: 2007
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6. Pairing and coherence transition in La1.82Sr0.18CuO4 strongly two-dimensional superconductor
We report conductivity fluctuation measurements in the La1.82Sr0.18CuO4 high temperature superconducting material. The conductivity fluctuation analysis was performed by utilizing the concept of the logarithmic derivative of the conductivity excess. Close and above the critical temperature Tc, we experimentally determine the occurrence of Gaussian and critic
Brazilian Journal of Physics. Publicado em: 2006-09
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7. Uso de renderização volumétrica e realidade virtual para problemas de percolação na engenharia
No processo da recuperação do petróleo, a heterogeneidade das rochas exerce um impacto enorme na forma como os líquidos se movem no reservatório, definindo quanto petróleo pode ser recuperado. A fim de estudar esta variabilidade, a teoria da percolação, que descreve fenômenos envolvendo geometria e conectividade é um modelo muito útil. Os resultad
Publicado em: 2005
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8. Percolation of Monte Carlo clusters
Percolation theory is of interest in problems of phase transitions in condensed matter physics, and in biology and chemistry. More recently, concepts of percolation theory have been invoked in studies of color deconfinement at high temperatures in Quantum Chromodynamics. In the present paper we briefly review the basic concept of percolation theory, exemplif
Brazilian Journal of Physics. Publicado em: 2004-03
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9. Path integrals and perturbation theory for stochastic processes
We review and extend the formalism introduced by Peliti, that maps a Markov process to a path-integral representation. After developing the mapping, we apply it to some illustrative examples: the simple decay process, the birth-and-death process, and the Malthus-Verhulst process. In the first two cases we show how to obtain the exact probability generating f
Brazilian Journal of Physics. Publicado em: 2003-03
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10. A novel percolation theory for high temperature superconductors
We present a percolation theory for the high-Tc oxides pseudogap and Tc dependence on the hole level. The doping dependent inhomogeneous charge structure is modeled by a distribution which may represent the stripe morphology and yield a spatial distribution of local Tc(r). The temperature onset of spatial dependent superconducting gap is identified with the
Brazilian Journal of Physics. Publicado em: 2002-09
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11. Percolation transitions and wetting transitions in stochastic models
Stochastic models with irreversible elementary processes are introduced, and their macroscopic behaviors in the infinite-time and infinite-volume limits are studied extensively, in order to discuss nonequilibrium stationary states and phase transitions. The Domany-Kinzel model is a typical example of such an irreversible particle system. We first review this
Brazilian Journal of Physics. Publicado em: 2000-03
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12. A posição dos adjetivos no interior do sintagma nominal : perspectivas sincronica e diacronica
This thesis investigates the position of adjectives inside noun phrases in Portugues. Its aim ís to determine the restrictions responsible for the contrast between (1) and (2) below: (1) a. um livro interessante (lit.: a book interesting) b. um interessante livro (lit.: an interesting book) (2) a. um livro vermelho (lit.: a book red) b. " um vermelho livro
Publicado em: 1991