949 resultados para work function measurements
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Mirandópolis/SP appeared in 1934 from the railroad “the Brazil Northwest”, that there it served one of the points of its stretch that had as main function to drain the agricultural production northwestern native of São Paulo of that time. The installation of the town happened absent of concerns with initial urbanístico planning, thus modifying its natural landscape and modifying characteristic ambient without compensatory measures aiming at a future expansion of the urban mesh. Fact this that still causes today consequences the quality of life of the people and also the observed thermal comfort later. Ahead of this, the present work had for objective to identify through measurements of temperature and relative humidity of the city of Mirandópolis/SP the differences that in the fabric urban they corroborate for a comfort situation or thermal discomfort to the outdoors in accordance with the Diagram Bioclimático de Olgyay the collection of data was made throughout the month of July of 2011 involving the attainment of information of Temperature and relative humidity of air and questionnaire applied to the passer-bys in the act of the measurements. Also approaching the different thermal dynamic of the zones of housing in relation to the Urban Cannyon that develops the commerce as predominant activity. This research sample that, although a city to be small, the quality of life of its inhabitants is not only guaranteed by the transport or that its thermal comfort reveals inside homogeneous of the urban perimeter, but that it has yes heterogeneidade in the scope of the urban climate in these spaces
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In this work, air dielectric barrier discharge (DBD) operating at two different frequencies (60 Hz and 17 kHz) was used to improve surface properties of polypropylene (PP). The changes in surface hydrophilicity were investigated by contact angle measurements. The modifications in chemical composition of PP surface were studied by X-ray photoelectron spectroscopy (XPS) and Fourier-transformed infrared spectroscopy (FTIR). The PP roughness were analyzed before and after the DBD treatment using atomic force microscopy (AFM). In order to compare the results obtained at different frequencies, the analyses are presented as a function of the deposited energy density. The results show that both DBD treatments led to formation of low-molecular weight oxidized material (LMWOM). It tends to agglomerate into small mounts on the surface, as shown by AFM analyses. These structures are weakly bounded to the surface and can be easily removed by rinsing in polar solvents. After washing the DBD-treated samples, the PP partially recovers its original wetting characteristics. This suggests that oxidation also occurred at deeper and more permanent levels on the PP samples. Comparing both DBD treatments, the 17 kHz process was found to be more efficient in introducing oxygen groups to the PP surface
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In this paper we investigate the C ` versions of contact and right equivalences of real semi-quasihomogeneous C ` function germs, 1 ≤ ` ≤ ∞. The C ` -right equivalence implies C ` -contact equivalence for any 1 ≤ ` ≤ ∞ and in this work we show, up to certain conditions, that for semi-quasihomogeneous C ` function germs the converse is also true. As a consequence, we recover some known results about C∞-right and C∞-contact equivalences of C∞ function germs. We note that we are considering semi-quasihomogeneous function germs with no additional hypothesis of isolated singularity at zero.
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A monitoring network of atmospheric electric field covering the Vale do Paraiba region was implemented. The sensors were located on different sites with different altitude and geographic topology. The present work reports the study carried on those sensors in order to verify the necessity of using some correction factor to the measured local electric field intensity due to effects of local environment. The measurements were done in continuous 24 hours per day with the data recorded on registers in each device accumulating information during a period of four months. The relation between the electric field values by each sensor was compared to the reference located on Sao Jose dos Campos city using the same period. In a graphical analysis using the local field intensity and the reference, the data were fitted to a straight line obtained by minimum square method. Variation up to 95% was observed between the field values in some sensors. Another method was proposed, comparing the mean values of the electric field in a function of time. The variation in some sensors reached up to 133%. We conclude that the variations are due to local atmospheric conditions and no correction factor is required on the electric field sensors
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Pós-graduação em Ciência dos Materiais - FEIS
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This work describes the synthesis of highly conducting antimony-doped tin oxide (ATO) nanocrystals prepared via a nonaqueous sol–gel route in the size range of 4–6 nm and provides insights into its electrical properties. The antimony composition was varied from 1 to 18 mol% and the lowest resistivity (4.0 × 10−4Ω·cm) was observed at room temperature in the SnO2:8.8 mol% Sb composition. The samples were evaluated by X-ray diffraction, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, and scanning electron microscope, and resistivity measurements were taken in the four-probe mode in the temperature range of 13–300 K. The results show highly crystalline nanoparticles in a monodisperse colloidal system, dependence on the shape of ATO nanoparticles as a function of Sb distribution, low resistivity, and semiconductor–metal transition.
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In this work, sufficient conditions for the existence of switching laws for stabilizing switched TS fuzzy systems via a fuzzy Lyapunov function are proposed. The conditions are found by exploring properties of the membership functions and are formulated in terms of linear matrix inequalities (LMIs). Stabilizing switching conditions with bounds on the decay rate solution and H1 performance are also obtained. Numerical examples illustrate the effectiveness of the proposed design methods.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)