Mechanism Of Tunneling
Mostrando 1-12 de 15 artigos, teses e dissertações.
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1. Mecanismo da decomposição e reações com radicais em acetatos / Decomposition mecanism and radical reactions with acetates
Computational studies on methyl and ethyl acetates molecules using ab initio and density functional calculations exploring the unimolecular mechanism, induced by multiphoton absorption, and the bimolecular reactions with OH and Cl radicals, have been performed in this work. Analysis of the calculated energy barriers and rate constants of unimolecular reactio
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 18/05/2011
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2. Redes de osciladores dissipativos : o modelo duplicado de Caldeira-Leggett, transferência quase-perfeita de estados e recoerência
In this work we treat firstly what we call the double Caldeira-Leggett model, which consists on the approach to the dynamics of two dissipative harmonic oscillators via Feynman-Vernon theory. We derived and solved the associated master equations in two different situations where i) each oscillator is coupled to its own reservoir and ii) both oscillators are
Publicado em: 2010
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3. Moleculas organicas sobre superficies metalicas : uma investigação teorica / Organic molecules on metalic surfaces : a thoretical investigation
Recently, the first molecular nanowheel was characterized with scanning tunneling micro-scope experiments. It was demonstrated that a specifically designed hydrocarbon molecule (C44H24) could roll over a copper substrate along the [110] direction of a surface. The molecule consists in two wheels based on two triptycene groups which are connected by an axle.
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 08/07/2009
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4. Tunnel Broker: an architecture of tunneling to instrument the Task Force BRv6TF and to speed up the adoption of the IPv6; / Tunnel Broker: uma arquitetura de tunelamento para instrumentar a Força Tarefa BRv6TF e acelerar a adoção do IPv6;
A principal aposta das entidades de Forças Tarefas Regionais e Nacionais, para acelerar o crescimento global na adoção do IPv6 (Internet Protocol version 6), como padrão de protocolo de comunicação pela internet, é adotá-lo de forma gradativa. Tal estratégia somente é possível, pelos esforços e pesquisas que ocorrem em torno de mecanismos de coex
Publicado em: 2006
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5. Rock drilling using hot supersonic jet / Perfuração de rochas por jato supersônico quente
This work discusses the possibility of applying the thermal spallation technique i.e., the use of hot supersonic jets for drilling and tunneling processes, on certain rocks of interest of the oil drilling industry. This technique was successfully used on granite rocks achieving high penetration rates (1 to 10 m/hr) compared to conventional techniques. An exp
Publicado em: 2004
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6. Bulk plasmon-assisted ion neutralization at metal surfaces
The mechanism for ion neutralization at metal surfaces via surface plasmon excitation was previously suggested. It was shown that this mechanism is of comparable probability as the other two well studied mechanisms, namely, Auger and resonance tunneling neutralizations. In the present work we study the probability of exciting a bulk rather than surface plasm
Brazilian Journal of Physics. Publicado em: 2002-12
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7. Study of dynamical dipole moment in an asymmetric double quantum well
A study of the dynamical behavior of the charge in an asymmetric double quantum well is presented. In particular, the time behavior of intrasub-band dipole moment which is induced by intersub-band optical excitation is analyzed in two aspects: first, design of the quantum wells in order to spatially separate the charge and store it and second study the dynam
Brazilian Journal of Physics. Publicado em: 2002-06
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8. Modelamento de transistores bipolares de heterojunção
A study about current transport mechanism through a heterojunction is presented. Drift and diffusion mechanism are not enough to describe the electrical current (due to a spike in the conduction band of the Npn transistor). This has led to the introduction of the Thermionic-Emission mechanism. The Ebers-Moll and Gummel-Poon models are also compatible with th
Publicado em: 1995
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9. Propriedades estruturais e eletricas dos carvões minerais brasileiros
Inspection of X-ray diffraction patterns revealed that the amorphous structure of Brazilian natural coals evolue towards a more ordered state after heat treatment at high temperatures. The structure of samples carbonized in vacuum above 2000 ºC is similar to that of commercial graphite. The microscopic particles with graphitic structure which characterized
Publicado em: 1980
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10. Imaging of single uncoated DNA molecules by scanning tunneling microscopy.
Scanning tunneling microscope images of DNA molecules absorbed onto highly oriented pyrolytic graphite have been obtained. Three methods of deposition and sample preparation have been utilized. In the first method, a highly concentrated solution of DNA is sonicated, and a drop is deposited on freshly cleaved graphite. Under these conditions, the molecules te
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11. Two-dimensional ordering of the DNA base guanine observed by scanning tunneling microscopy.
Guanine, one of the four DNA bases, has been observed by tunneling microscopy to form a two-dimensional ordered structure on two crystalline substrates, graphite and MoS2. The two-dimensional lattice formed by guanine is nearly identical on the two surfaces, and heteroepitaxy appears to be the growth mechanism in both cases. Although the resolution of molecu
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12. Quantum aspects of brain activity and the role of consciousness.
The relationship of brain activity to conscious intentions is considered on the basis of the functional microstructure of the cerebral cortex. Each incoming nerve impulse causes the emission of transmitter molecules by the process of exocytosis. Since exocytosis is a quantal phenomenon of the presynaptic vesicular grid with a probability much less than 1, we