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Wyszukujesz frazę "Zukowski, K." wg kryterium: Autor


Wyświetlanie 1-3 z 3
Tytuł:
Percolation Phenomena in $Cu_{x}(SiO_{y})_{100-x}$ Nanocomposite Films Produced by Ion Beam-Sputtering
Autorzy:
Koltunowicz, T.
Zukowski, P.
Czarnacka, K.
Svito, I.
Fedotov, A.
Powiązania:
https://bibliotekanauki.pl/articles/1402230.pdf
Data publikacji:
2015-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
84.37.+q
72.80.Ga
73.22.-f
61.46.Df
64.60.ah
Opis:
In this paper the results of examinations of nanocomposites $Cu_{x}(SiO_{y})_{100-x}$ produced by ion beam sputtering using argon ions were presented. The examinations were performed by the use of ac devices for measuring frequency in the range 50 Hz-1 MHz and temperatures from 81 K to 273 K. The measurements were performed for the samples directly after production. Based on temperature dependences of conductivity σ , which were determined at the frequency 100 Hz, the Arrhenius graphs were prepared. From these graphs conductivity activation energies ΔE were calculated. Dependences of conductivity and activation energy of electrons on the metallic phase content x at the frequency 100 Hz were determined. Analysis of the obtained dependences shows that conductivity is a parabolic function of the metallic phase content x in nanocomposites. Changes of activation energies of nanocomposites, in which metallic phase contents are in the ranges x < 12 at.% and x > 68 at.%, demonstrate negative values - metallic type of conductivity. In the range 12 at.% < x < 68 at.% activation energies have positive values - the dielectric type of conductivity. It was established that for the metallic phase content of about 68 at.% the real percolation threshold occurs, and the conduction changes from dielectric to metallic type.
Źródło:
Acta Physica Polonica A; 2015, 128, 5; 908-911
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ion Beam Formation of Electrocatalysts for Direct Methanol and Ethanol Fuel Cells on the Basis of Carbon Catalyst Supports
Autorzy:
Poplavsky, V.
Dorozhko, A.
Luhin, V.
Matys, V.
Zukowski, P.
Czarnacka, K.
Powiązania:
https://bibliotekanauki.pl/articles/1033764.pdf
Data publikacji:
2017-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.37.Hk
81.15.Jj
81.05.U-
82.45.Jn
82.80.Fk
82.80.Yc
88.20.ff
88.30.pd
88.30.pf
Opis:
Ion-beam modification of materials whose service properties are mainly controlled by the surface composition is of especial interest, in particular, for electrocatalysts, namely electrodes of fuel cells - perspective chemical current sources. A catalyst is needed for effective operation of fuel cell. In this paper active layers of the electrocatalysts were prepared by ion beam assisted deposition of catalytic (platinum) and activating (cerium) metals onto carbon (AVCarb® Carbon Fiber Paper P50 and Toray Carbon Fiber Paper TGP-H-060 T) catalyst supports. Formation of layers by ion beam assisted deposition by means of the deposition of metal and mixing of precipitating layer with the substrate by accelerated ions of the same metal, was carried out. Metal deposition and mixing between the precipitable layer and surface of the substrate by accelerated (U=10 kV) ions of the same metal were conducted from a neutral vapor fraction and plasma of vacuum arc discharge of a pulsed electric arc ion source. Study of the morphology and composition of layers was carried out by the scanning electron microscopy, energy dispersive X-ray microanalysis, X-ray fluorescence analysis, and the Rutherford backscattering spectrometry methods. According to the investigations with the use of cyclic voltammetry, the electrocatalysts with the prepared layers exhibited catalytic activity in the reactions of electrochemical oxidation of methanol and ethanol, which form the basis for the principle of operation of low temperature direct methanol and direct ethanol fuel cells.
Źródło:
Acta Physica Polonica A; 2017, 132, 2; 278-282
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of Electronic Structure of Zn$\text{}_{1-x}$Mg$\text{}_{x}$ Mixed Crystals by Compton Spectroscopy Method
Autorzy:
Reniewicz, H.
Andrejczuk, A.
Dobrzyński, L.
Rećko, K.
Waliszewski, J.
Żukowski, E.
Firszt, F.
Łęgowski, S.
Męczyńska, H.
Szatkowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1952072.pdf
Data publikacji:
1996-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.-b
71.45.-d
61.80.Ed
71.55.Gs
Opis:
The first experimental study of the Compton profiles of Zn$\text{}_{1-x}$Mg$\text{}_{x}$Se for x=0.25, 0.47, 0.56 mixed crystals is presented. The Compton profiles were measured with the use of the $\text{}^{241}$Am radioactive source with a resolution of 0.57 a.u. The experimentally obtained Compton profiles were compared with the theoretical ones based on the free-atom model. The results are interpreted in terms of outermost electrons of Zn and Mg being promoted to the higher momentum states, and 4p-electrons of Se becoming more delocalised in a solid, being thus promoted to the lower momentum states.
Źródło:
Acta Physica Polonica A; 1996, 90, 5; 907-910
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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