Electrons Emission
Mostrando 13-24 de 45 artigos, teses e dissertações.
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13. Modelamento computacional de ponteiras de emissão de campo / Computational modeling of field emission tips
Este trabalho tem como objetivo o estudo do comportamento elétrico de uma ponteira de emissão de campo, modelada na forma de um hemisfério sobre um poste, através de recursos computacionais (simulações). Escolhemos o software comercial Ansys, que utiliza o método dos elementos finitos nas análises dos fenômenos físicos para obtenção do campo elé
Publicado em: 2007
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14. FluorescÃncia induzida por plasmons superficiais em corantes
Plasmons, collective oscillations of conduction electrons, may have large influence on the optical properties of metallic microstructures and nanoestructures, and can be exploited in photonic devices. In this work, we produce metallic thin films by the method of evaporation at low pressure and characterized them by optical reflectivity measurements. The film
Publicado em: 2007
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15. Thermoluminescence, electron paramagnetic resonance and color centers properties of diopside / Propriedades de termoluminescência, de ressonância paramagnética eletrônica e de centros de cor de diopsídio
Diopside of chemical formula, CaMgSi2O6, a natural silicate mineral has been investigated concerning its Thermoluminescence (TL), Electron Paramagnetic Resonance (EPR) and Reflectance properties. Synthetic, pure or doped diopside, produced in the laboratory, has been investigated. Samples annealed at 600 `GRAUS´ C for one hour, to eliminate previously induc
Publicado em: 2007
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16. Polimetalates porphyrins with ruthenium phosphinics complex to application in homogeny catalyze, Non Linear Optic and Langmuir-Blodgett film preparation / Porfirinas polimetaladas com complexos periféricos de rutênio com aplicações em catálise homogênea, óptica não linear e montagem de filmes de Langmuir-Blodgett
A novel metaloporphyrin with ruthenium complexes, {H2-TPyP[RuCl(dppb)(Xbipy)] 4}(PF6)4 and {M-TPyP[RuCl(dppb)(X-bipy)]4}(PF6)4, (where M = Mn(III), Co(II) and Zn(II), X = Me- MeO- and Cl-) has been synthesized and structurally characterized by 31P{1H} magnetic resonance, UV-Vis and IR spectroscopy, cyclic voltammetry and CHN. The catalytic activity of {Mn-TP
Publicado em: 2007
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17. Ressonant energy transfer and transport mechanisms in molecular electronic devices based on Alq3 organic molecule. / Transferência resonante de energia e mecanismos de transporte eletrônico em dispositivos moleculares baseados na molécula orgânica Alq3.
The aim of the present work was to study and analyses the energy and electron transfer process in molecular devices. The molecular devices were fabricated by using the polystyrene polymer because this material, as it was verified in this work, showed a good insulator features. The optical and electrical molecular devices were fabricated by using the spin-coa
Publicado em: 2007
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18. Propriedades fotoquímicas e fotofísicas de novos materiais derivados quinolinas e di naftalimidas / Photochemistry and photophysical properties of new materials derivatives of quinolines and Di-naphtalimides
Excited state proto transfer reactions in aqueous media is among current themes in photochemistry research. Shortly, organic molecules having acid or basic groups and presenting excited state lifetimes long enough, competitive prototropic reactions can occur. This phenomenon is attributed to an isoelectronic state of the ground state molecule and up to seven
Publicado em: 2007
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19. Inductively coupled fluorine plasmas. / Plasmas fluorados com acoplamento indutivo.
In this work, inductively coupled plasmas have been studied, using optical emission spectroscopy and electrical measurements. Four gases were analysed : argon, being an inert gas, oxygen because it is slightly electronegative, SF6 because it is very eletronegative and also etches silicon and its compounds and CF4 because it also etches silicon and its compou
Publicado em: 2006
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20. A influência dos parâmetros do vento solar na emissão de AKR durante tempestades magnéticas / The influence of the solar wind parameters on the AKR emission during magnetic storms
Several phenomena could be better studied and even disclosed after the development of the satellites and spacecrafts. Auroral Kilometric Radiation (AKR) is one of these phenomena. AKR was first detected only about thirty years ago; its typical frequencies are too low to penetrate earthward across the ionosphere. This radiation is generated through wave-parti
Publicado em: 2006
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21. Desenvolvimento experimental de uma camara para medida de emissão de eletrons por catodos frios / Development of a vacuum set-up for the measurement of cold cathode field electron emission
Foi desenvolvida uma câmara de vácuo para estudo das propriedades elétricas de emissão de elétrons por catodos frios de vários materiais de interesse tecnológico, por exemplo, diamante dopado, filmes de carbono diamantífero e silício. Na parte experimental realizamos um sistema de alto vácuo (bomba mecânica mais a bomba difusora), um sistema de po
Publicado em: 2005
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22. Design and construction of a current meter for field emitted electrons in vacuum for the characterization for nano-tube or nano-structured cold cathodes / Projeto e construção de um medidor de corrente de eletrons emitidos no vacuo por campo eletrico para carcterização de catodos frios constituidos por nanotubos ou nanoestruturas ;
O progresso da pesquisa científica depende da qualidade e da disponibilidade de instrumentos confiáveis e de alta precisão, necessários para a exploração quantitativa de novos fenômenos, possibilitando a construção de modelos mais avançados e mais sofisticados. Um dos fenômenos que tem despertado grande interesse é a emissão de elétrons da supe
Publicado em: 2005
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23. Electron Cyclotron Emission in the TCABR Tokamak: An Experimental Study. / "Emissão Eletrociclotrônica no Tokamak TCABR: Um Estudo Experimental"
In this work, an experimental study of the Electron Cyclotron Emission (ECE) in the TCABR Tokamak, is described. An ECE sweeping heterodyne radiometer, operating in the 50-85 GHz frequency range, was installed, calibrated and used to detect ECE radiation in the second harmonic extraordinary mode from thermal plasma discharges. The noise temperature, amplitud
Publicado em: 2005
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24. Electron cyclotron emission simulation from TCABR plasmas
Electron cyclotron emission due to electrons described by a particular distribution function has been studied. The latter presents an extended tail generated by the interaction of the Lower Hybrid wave with the plasma as compared to the Maxwellian distribution function. For this purpose a new code has been developed which calculates for an arbitrary distribu
Brazilian Journal of Physics. Publicado em: 2004-12