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Wyszukujesz frazę "82.30.Lp" wg kryterium: Temat


Wyświetlanie 1-5 z 5
Tytuł:
Thermal Decomposition Kinetics of Algerian Tamazarte Kaolin by Differential Thermal Analysis (DTA)
Autorzy:
Sahnoune, F.
Heraiz, M.
Belhouchet, H.
Saheb, N.
Redaoui, D.
Powiązania:
https://bibliotekanauki.pl/articles/1033455.pdf
Data publikacji:
2017-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
82.30.Lp
81.05.Je
81.05.Mh
81.70.Pg
Opis:
In the present study, the kinetics of meta-kaolinite (Al₂O₃·2SiO₂) formation from Algerian Tamazarte kaolin was investigated by using differential thermal analysis. The differential thermal analysis and the thermogravimetric experiments were carried out on samples between room temperature and 1400°C, at heating rates from 10 to 40°C min¯¹. X-ray diffraction was used to identify the phases present in the samples. The activation energies measured by differential thermal analysis from isothermal and non-isothermal treatments using Johnson-Mehl-Avrami methods with Ligero approximation and using Kissinger-Akahira-Sunose methods were around 145 and 159 kJ/mol, respectively. The Avrami parameter n which indicates the growth morphology parameters were found to be almost equal to 1.60, using non-isothermal treatments, and equal to 1.47 using isothermal treatments. The numerical factor which depends on the dimensionality of crystal growth was 1.60 obtained using Matusita et al. equation. The frequency factor calculated using the isothermal treatment is equal to 1.173× 10⁷ s¯¹. Analysis of the results have shown that bulk nucleation was dominant during kaolinite transformation, followed by three-dimensional growth of meta-kaolinite with polyhedron-like morphology, controlled by diffusion from a constant number of nuclei.
Źródło:
Acta Physica Polonica A; 2017, 131, 3; 382-385
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
EPR characteristics of activated carbon for hydrogen production by the thermo-catalytic decomposition of methane
Autorzy:
Więckowski, A.
Najder-Kozdrowska, L.
Rechnia, P.
Malaika, A.
Krzyżyńska, B.
Kozłowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1158900.pdf
Data publikacji:
2016-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
33.35.+r
61.66.Hq
76.30.-v
82.30.Lp
82.65.+r
88.30.ej
Opis:
The electron paramagnetic resonance (EPR) method was used to characterize samples of activated coal before and after reactions of the catalytic decomposition of methane and ethanol at temperatures of 1023 K (750°C), 1123 K (850°C) and 1223 K (950°C). The EPR parameters: spectroscopic splitting factor g, peak-to-peak linewidth ΔBₚₚ, and spin concentration c were measured. During the ethanol-assisted catalytic decomposition of methane carbon-located-spin radicals are partially transformed into oxygen-located-spin radicals.
Źródło:
Acta Physica Polonica A; 2016, 130, 3; 701-704
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Increase of Hydrogen Storage Capacity of CNTs by Using Transition Metal, Metal Oxide-CNT Nanocomposites
Autorzy:
Larijani, M.
Safa, S.
Powiązania:
https://bibliotekanauki.pl/articles/1205209.pdf
Data publikacji:
2014-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.82.Rx
68.37.Lp
81.07.De
88.30.R-
Opis:
In this paper, we examined the synergetic effect of transition metals or their oxides as decorative agent with carbon nanotubes on the hydrogen storage capacity. The $TiO_2$, Pd, and PdO shell nanoparticles were used as decorative agent on the surface of carbon nanotubes. The samples were investigated by X-ray diffraction, Raman spectroscopy and transmission electron microscopy. The thermal stability was investigated by thermogravimetric analysis testing. The hydrogen storage capacity was measured by a custom-made Sieverts apparatus. The Pd and $TiO_2$ doped carbon nanotube shows the most marked hydrogen storage capacity, 7 times higher than pristin carbon nanotubes after 30 min storage. The results show that the hydrogen storage capacity of the PdO shell- carbon nanotube composite is very low in comparison with those of two others and does not represent a significant difference with that of carbon nanotubes.
Źródło:
Acta Physica Polonica A; 2014, 126, 3; 732-735
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation of Silicon Oxycarbide Composites Toughened by Inorganic Fibers via Pyrolysis of Precursor Siloxane Composites
Autorzy:
Strachota, A.
Černý, M.
Glogar, P.
Sucharda, Z.
Havelcová, M.
Chlup, Z.
Dlouhý, I.
Kozák, V.
Powiązania:
https://bibliotekanauki.pl/articles/1503708.pdf
Data publikacji:
2011-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Je
81.05.Mh
82.30.Lp
Opis:
The optimization of silicon oxycarbide (SiOC) synthesis (sol-gel/pyrolysis) is described, starting from methyltriethoxysilane, dimethyldiethoxysilane, tetraethoxysilane, ethyltriethoxysilane and propyltriethoxysilane. Variation of final elemental composition was tested via change of monomer ratios and combinations. The main aim was to achieve low weight losses during cure and pyrolysis and high micromechanical properties. Gas chromatography and mass spectroscopy was used to analyse the by-products of cure and pyrolysis, indicating a prominent role of cyclosiloxane and polyhedral oligomeric silsesquioxane (POSS) oligomers. Best results were obtained with high contents of methyltriethoxysilane in the monomers mixture.
Źródło:
Acta Physica Polonica A; 2011, 120, 2; 326-330
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Low-Temperature Magnetic Properties of Nanometric Fe-Based Particles
Autorzy:
David, B.
Schneeweiss, O.
Šantavá, E.
Alexandrescu, R.
Morjan, I.
Powiązania:
https://bibliotekanauki.pl/articles/1813905.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.16.Mk
82.30.Lp
75.50.Bb
75.75.+a
61.05.Qr
Opis:
Fe-based nanoparticles were prepared by laser-driven pyrolysis. The as-synthesised powder consists ofα-Fe and $Fe_3O_4//γ-Fe_2O_3$ nanoparticles embedded in a pyrolytic carbon matrix. The crystallite size of 1.8 nm forα-Fe was calculated using the Scherrer formula. The as-synthesised nanopowder was superparamagnetic. The maximum of the zero-field cooling curve was observed at 32 K and the distribution of blocking temperatures $g(T_B)$ peaked at 11 K. As a result of small particle sizes and the soft matrix, the Lamb-Mössbauer factor f was significantly higher at 4 K than at 293 K.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 561-564
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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