Wyniki wyszukiwania - BazTech

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Wpływ podwójnej warstwy dielektrycznej na powierzchniach elektrod na wytrzymałość elektryczną powietrza i sześciofluorku siarki

Zakrzewski S., Opydo W.

Poznan University of Technology Academic Journals. Electrical Engineering

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2012

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No. 70

113--119

PL

W pracy przedstawiono wyniki badań wpływu podwójnej warstwy dielektrycznej na powierzchniach elektrod na wytrzymałość elektryczną sprężonego powietrza i sprężonego sześciofluorku siarki. Badania prowadzono przy napięciu przemiennym o częstotliwości 50 Hz. Stwierdzono, że cienka powłoka izolacyjna na powierzchniach elektrod, złożona z warstwy tlenku aluminium i warstwy elektroizolacyjnego lakieru poliestrowego, powoduje znaczny przyrost wytrzymałości elektrycznej powietrza i sześciofluorku siarki. Stwierdzono, że największy procentowo przyrost wytrzymałości elektrycznej tych gazów powłoka powodowała przy ciśnieniach gazów wyższych od ciśnienia atmosferycznego (3•105 i 5•105 Pa). Do opracowywania wyników badań zastosowano program komputerowy Statistica [1].

EN

The paper presents results of an investigation of the impact of dielectric double layer located at the electrode surface on the electric strength of an insulation system provided with compressed air and compressed sulphur hexafluoride (SF6) subject to alternate voltage of 50 Hz frequency. It was found that in the case of the insulation system with air or SF6 the electrode surface covered with the aluminum oxide layer and additionally insulating varnish improves the electric strength of the system. It was observed that the largest percentage increase electric strength has been caused by gas pressures higher than atmospheric pressure (3•105 i 5•105 Pa). The test results were developed with the use of Statistica statistical analysis software.

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The effect of aluminum oxide layer located at the electrode surface on the electric strength of an insulation system provided with sulphur hexafluoride

Zakrzewski S., Opydo W.

Poznan University of Technology Academic Journals. Electrical Engineering

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2011

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No. 67-68

123-129

EN

The paper presents investigation results of the effect of aluminum oxide layer located at the electrode surface on the electric strength of an insulation system with sulphur hexafluoride (SF6) subject to alternate voltage of 50 Hz frequency. The tests have been carried out under the SF6 pressure of 1*105, 3*105 and 5*105 Pa. It was found that in case of the insulation system with SF6 the electrode surface covered with the aluminum oxide layer improves the electric strength of the system, from 12 to 30 percent, according to the gas pressure. The electrode surface covered with double insulation layer composed of aluminum oxide and polyurethane or silicon paint gave still better improvement of the strength of the SF6 insulation system. In order to determine the parameters of the formula describing the mathematical dependence of the electric strength of the considered systems on the applied pressure the Statistica computer software has been used.

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Efekty powierzchniowej struktury metali w procesach elektrochemicznych

Sobkowski J., Jurkiewicz-Herbich M.

Wiadomości Chemiczne

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2004

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[Z] 58, 5-6

449--476

EN

It is known that both the nature and structure of a metal have a great influence on electrochemical processes. Interpretation of a mechanism of electrochemical reactions that occur on polycrystalline electrodes is often complicated because of their heterogeneous structure consisting of randomly distributed monocrystals on the surface. To avoid this problem, electrodes with well defined surfaces are commonly used in electrochemical experiments. In this paper, effects of the surface structure of a metallic electrode on properties of the double layer of the metal/solution interface, electrosorption and also on the electrochemical reactions has been reviewed. The presented data refer mainly to the basic planes of monocrystalline electrodes of face-centered cubic system. In first three chapters problems of the double layer structure of monocrystalline electrodes, the correlation of the potential of zero charge and work function, and the competition of a substrate and water molecules in the electrosorption process in relation to the hydrophilicity of metals are discussed. In chapters 4 and 5 the influence of the surface structure on the adsorption of organic molecules, strongly and weakly interacting with the electrode surface, is reviewed. It was shown that the surface concentration of adsorbate depends not only on the number of adsorption sites (assumed as the surface atom density) but also on the geometry of adsorbed molecule as well as on the kind and size of the supporting electrolyte anions. The latter play a very important role when the interaction of an adsorbed molecule and a metal is weak. Chapter 6 concerns the role of the electrode surface structure in the hydrogen ion discharge and also underpotential deposition of ions. The relationship between electrocatalytic properties of an electrode and its surface structure is presented in chapter 7. The kinetics of oxidation of methanol and formic acid at different planes of the platinum electrode and various products of the reduction of carbon oxide on copper monocrystalline electrodes are given as examples.