Nonequilibrium Systems
Mostrando 1-12 de 59 artigos, teses e dissertações.
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1. Aplicação do Formalismo CTP em uma Ação com Operador Pseudo-Diferencial
Resumo O formalismo CTP (closed-time-path) é uma ferramenta matemática para calcular funções de Green em sistemas físicos. A principal vantagem desta técnica é a de que, ao contrário do formalismo de Feynman, o formalismo CTP pode ser aplicado em sistemas fora do equilíbrio. Por outro lado, em física da matéria condensada, alguns modelos não loca
Rev. Bras. Ensino Fís.. Publicado em: 25/11/2019
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2. Padrões de Turing em sistemas químicos
Spontaneous pattern formation in reaction-diffusion systems was theoretically proposed by Alan M. Turing in 1952. His breakthrough conceptions of chemical self-organization were able to explain how patterns emerge in nature and the symmetry breaking, which are of utmost importance, for instance, in the context of origin of life. Along with the experimental o
Quím. Nova. Publicado em: 2016-05
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3. Avalanches e redes complexas no modelo Kinouchi-Copelli / Avalanches and complex networks in Kinouchi-Copelli model
The capacity of a sensory system in efficiently detecting stimuli is usually given by the dynamic range, a simple measure of the range of stimulus intensity over which the network is sensible enough. Many times biological systems exhibit large dynamic ranges, covering many orders of magnitude. There is no easy explanation for that, since individual neurons p
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 02/08/2012
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4. Controle de Corrente de Spin em Pontos Quânticos na Presença de Tensões de Porta Moduladas no Tempo
Since Loss &DiVincenzo proposal to use confined electron spins in quantum dots (QDs) as a building block for qubits in solid state systems, spin-dependent transport in QDs has attracted a lot of attention. The interest for this system increased even further with the recent experimental developments to coherently control (initialization-manipulation-read out)
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 09/08/2011
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5. A Equação-Mestra: atingindo o equilíbrio
In the last years, a great interest in nonequilibrium systems has been witnessed. Although the Master Equations are one of the most common methods used to describe these systems, the literature about these equations is not straightforward due to the mathematical framework used in their derivations. The goals of this work are to present the physical concepts
Química Nova. Publicado em: 2011
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6. Simulações de sensores de gás nanoscópicos baseados em nanotubos de carbono: estrutura eletrônica e transporte de elétrons / Computational simulations of nanoscopic gas sensors based on carbon nanotubes: electronic structure and electronic transport
Since their discovery by S. Iijima in 1991, carbon nanotubes have been considered as one of the most promising nanostructured materials for the development of new nanoscopic electronic devices. Due to its high surface area to volume ratio, this material stands out as a candidate for possible gas sensoring applications. In this thesis, we have studied, by mea
Publicado em: 2011
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7. The role of nonequilibrium thermo-mechanical statistics in modern technologies and industrial processes: an overview
The nowadays notable development of all the modern technology, fundamental for the progress and well being of world society, imposes a great deal of stress in the realm of basic Physics, more precisely on Thermo-Statistics. We do face situations in electronics and optoelectronics involving physical-chemical systems far-removed-from equilibrium, where ultrafa
Brazilian Journal of Physics. Publicado em: 2010-03
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8. Vacancies in carbon nanotubes: electronic, structural and transport properties / Vacâncias em nanotubos de carbono: propriedades eletrônicas, estruturais e de transporte
The main purpose of this dissertation is the study of the electronic and structural properties in the presence of different types of vacancies, in one of the most promising materials for nanoelectronics, carbon nanotubes. The defects studied in this work are monovacancy and multivacancies in (5, 5) armchair carbon nanotubes. For that purpose perform quantum
Publicado em: 2008
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9. Entropy production in nonequilibrium systems described by a Fokker-Planck equation
We study the entropy production in nonequilibrium systems described by a Fokker-Planck equation. We have devised an expression for the entropy flux in the stationary state. We have found that the entropy flux can be written as an ensemble average of an expression containing the force and its derivative. This result is similar to the one used by Lebowitz and
Brazilian Journal of Physics. Publicado em: 2006-12
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10. Nonequilibrium modeling of an ammonia-water rectifyng column via fundamental thermodynamic and transport relations
A nonequilibrium heat and mass transfer model is presented for the steady-state operation of a rectifying column, employed in ammonia-water absorption refrigeration systems to dehumidify the ammonia vapor leaving the generator. The thermodynamic state relations of the mixture are derived from two equations representing the Gibbs free energy in terms of tempe
Brazilian Journal of Chemical Engineering. Publicado em: 2006-12
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11. Non-Linear electron mobility in n-doped III-Nitrides
A theoretical study of the mobility of n-doped III-Nitrides in wurtzite phase is reported. We have determined the nonequilibrium thermodynamic state of the bulk n-InN, n-GaN, and n-AlN systems - driven far away from equilibrium by a strong electric field - in the steady state, which follows after a very fast transient. For this we solve the set of coupled no
Brazilian Journal of Physics. Publicado em: 2006-06
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12. Thermo-statistics of irreversible processes: a Boltzmann-Gibbs-style ensemble formalism
The area of Physics indicated in the title is nowadays of quite relevant interest, not only from the purely scientific point of view, but specially for its applied aspects associated to the present-time point-first-technologies. A particular research trend in the theory of irreversible processes, which are evolving in time in systems arbitrarily departed fro
Brazilian Journal of Physics. Publicado em: 2006-03