Autor: Więckowski, A. - 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:: 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

Skocz do pozycji: 3.

Tytuł:: Influence of Microwave Power on EPR Signal of Melanin Radical and Copper(II) Ions in DOPA-Melanin Complexes
Autorzy:: Najder-Kozdrowska, L.
Pilawa, B.
Więckowski, A.
Buszman, E.
Wrześniok, D.
Powiązania:: https://bibliotekanauki.pl/articles/1399522.pdf
Data publikacji:: 2013-07
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 76.30.Rn
87.80.Lg
87.64.kh
Opis:: Electron paramagnetic resonance spectroscopy EPR was used for examination of microwave saturation in DOPA-melanin complexes with kanamycin and Cu(II) ions. The fast spin-lattice relaxation processes take place in system of paramagnetic metal ions. EPR signal of melanin radical saturated with growing of microwave power used during measurements. After adding Cu(II) ions a shortening of relaxation time is observed for EPR signal of melanin radical.
Źródło:: Acta Physica Polonica A; 2013, 124, 1; 112-114
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 4.

Tytuł:: Triplet States in DOPA-Melanin and in Its Complexes with Kanamycin and Copper Cu(II) Ions
Autorzy:: Najder-Kozdrowska, L.
Pilawa, B.
Buszman, E.
Więckowski, A.
Świątkowska, L.
Wrześniok, D.
Wojtowicz, W.
Powiązania:: https://bibliotekanauki.pl/articles/1535688.pdf
Data publikacji:: 2010-10
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 61.66.Hq
76.30.Rn
87.64.kh
Opis:: The mono- and biradical forms of DOPA-melanin (DOPA-eumelanin) were studied by EPR spectroscopy in 100-300 K temperature range. The existence of triplet states in DOPA-melanin was proved. The analysis of EPR spectra has shown that in DOPA-melanin and its complexes with kanamycin and $Cu^{2+}$ ions, two kinds of paramagnetic centres exist. The first of them are in doublet ground state with spin S = 1/2 and they obey the Curie law. The paramagnetic centres of the second group are in thermally excited triplet state with spin S = 1 and in this case the Curie law is not fulfilled.
Źródło:: Acta Physica Polonica A; 2010, 118, 4; 613-618
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

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