Temat: HQ - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Multi-Component EPR Spectra of Coals with Different Carbon Content
Autorzy:: Pilawa, B.
Więckowski, A. B.
Pietrzak, R.
Wachowska, H.
Powiązania:: https://bibliotekanauki.pl/articles/2043651.pdf
Data publikacji:: 2005-08
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 61.66.Hq
76.30.Rn
Opis:: EPR spectra of lignite"Mequinenza" (Spain) (62.3 wt% C) and Polish orthocoking coal (87.8 wt% C) were compared. The spectra were superpositions of broad Gaussian, broad Lorentzian 1, and narrow Lorentzian 3 lines. Concentration of paramagnetic centers - mainly delocalizedπ electrons - responsible for narrow Lorentzian 3 lines increases with increase in carbon content in coal. Coal units with slow and fast spin-lattice relaxation processes exist in the two studied samples. Slow spin-lattice interactions occur in simple aromatic coal units with broad Gaussian and Lorentzian 1 lines. Fast spin-lattice relaxation processes are characteristic of large aromatic units with narrow Lorentzian 3 lines.
Źródło:: Acta Physica Polonica A; 2005, 108, 2; 403-407
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 2.

Tytuł:: EPR Studies of Carbonized Cellulose - Oxygen Interactions
Autorzy:: Pilawa, B.
Pietrzak, R.
Wachowska, H.
Babeł, K.
Powiązania:: https://bibliotekanauki.pl/articles/2043418.pdf
Data publikacji:: 2005-07
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 61.66.Hq
76.30.Rn
Opis:: EPR examination of cellulose carbonized at 400ºC and 600ºC has been performed. The aim of this work was to search a sample useful as the oximetric probe in biology and medicine. The higher paramagnetic centers concentration characterizes cellulose carbonized at 600ºC, which was found as the sensitive oximetric probe. Quasi-chemical bonds between cellulose molecules and paramagnetic O$\text{}_{2}$ molecules decrease paramagnetic centers concentration. A linear increase in paramagnetic centers concentration and a linear decrease in EPR linewidth with increasing time of sample evacuation were observed for cellulose carbonized at 600ºC. Oxygen affects spin-lattice interactions in carbonized cellulose.
Źródło:: Acta Physica Polonica A; 2005, 108, 1; 151-154
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 3.

Tytuł:: Groups of Paramagnetic Centres in Reduced and Methylated Low Rank Coal
Autorzy:: Pilawa, B.
Wachowska, H.
Kozłowski, M.
Więckowski, A.
Najder-Kozdrowska, L.
Powiązania:: https://bibliotekanauki.pl/articles/1401865.pdf
Data publikacji:: 2015-09
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 33.35.+r
61.66.Hq
76.30.-v
76.30.Rn
89.30.ag
Opis:: Low rank Illinois No. 6 coal was studied by electron paramagnetic resonance EPR spectroscopy. The parameters of EPR spectra (spectroscopic splitting factors g, linewidths $\DeltaB_{pp}$, concentrations of paramagnetic centres N) were measured for row and chemically treated coal (demineralized, reduced and methylated samples). The multi-component structure of experimental spectra of this coal was proved. Two groups of paramagnetic centres responsible for broad Lorentzian 1 and narrow Lorentzian 2 lines exist in studied samples. Paramagnetic centres connected with component lines revealed different behaviour during chemical treatments.
Źródło:: Acta Physica Polonica A; 2015, 128, 3; 264-267
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

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