Autor: Chodak, M. - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Solid State $\text{}^{13}C$ NMR Study of Modified Polyhydroxybutyrate
Autorzy:: Vrábel, P.
Hronský, V.
Fričová, O.
Koval'aková, M.
Chodák, I.
Alexy, P.
Powiązania:: https://bibliotekanauki.pl/articles/1382700.pdf
Data publikacji:: 2014-07
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 61.41.+e
76.60.-k
81.05.Lg
Opis:: Structural changes in polyhydroxybutyrate (PHB) brought about by addition of chain extender and/or plasticizer were studied using $\text{}^{13}C$ MAS NMR spectra, which were measured using the direct polarization technique at 30 and 98°C. Four resonances associated with the CO, CH, $CH_{2}$ and $CH_{3}$ groups of PHB were observed in the spectra. The $CH_{3}$ resonance appearing at 98°C shows splitting into two lines related to the crystalline and amorphous regions. Analysis of the $CH_{3}$ resonances made it possible to estimate the influence of applied modifications on crystallinity and distribution of conformations in amorphous and crystalline domains of PHB samples.
Źródło:: Acta Physica Polonica A; 2014, 126, 1; 419-420
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 2.

Tytuł:: Studies of the Verwey Transition in Magnetite
Autorzy:: Tarnawski, Z.
Wiecheć, A.
Madej, M.
Nowak, D.
Owoc, D.
Król, G.
Kąkol, Z.
Kolwicz-Chodak, L.
KozŁowski, A.
Dawid, T.
Powiązania:: https://bibliotekanauki.pl/articles/2041527.pdf
Data publikacji:: 2004-11
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 61.18.Bn
75.40.-s
71.20.Lp
Opis:: Studies of the specific heat and simultaneous AC magnetic susceptibility (ρ') and electric resistance of stoichiometric magnetite single crystal are presented. The temperature hysteresis of the Verwey transition is of 0.03 K found from the specific heat data confirming its first-order character. The continuous temporal change of ρ' at T$\text{}_{V}$ can be switched off by an external magnetic field without affecting the transition. The electrical resistance decreases continuously with increasing temperature with a rapid change of slope at the point when the phase transition is completed. It was concluded that the magnetic degrees of freedom do not actively participate in the transition and that the entropy released at T$\text{}_{V}$ may come from ordering electrons.
Źródło:: Acta Physica Polonica A; 2004, 106, 5; 771-775
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

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