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Wyszukujesz frazę "Petkova, M." wg kryterium: Autor


Wyświetlanie 1-6 z 6
Tytuł:
Conformation-Dependent Photophysics of Bifunctional Hydrogen Bond Donor/Acceptor Molecules
Autorzy:
Kijak, M.
Petkova, I.
Toczek, M.
Wiosna-Sałyga, G.
Zielińska, A.
Herbich, J.
Thummel, R.
Waluk, J.
Powiązania:
https://bibliotekanauki.pl/articles/1814016.pdf
Data publikacji:
2007-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
33.15.-e
02.70.-c
Opis:
A series of heteroazaaromatic molecules possessing both a hydrogen bond donor and acceptor groups linked by a single bond was studied using electronic absorption and fluorescence techniques, combined with quantum-chemical calculations. Fluorescence lifetimes and quantum yields strongly depend on the solvent. Double exponential decays are observed in alcohols. This was interpreted in terms of alcohol-induced syn-anti rotamerization in the ground electronic state. The driving force for the conformational change is provided by two factors: (a) solvent polarity increase; (b) the formation of two separate hydrogen bonds in the anti species. In the syn structure, formation of cyclic hydrogen bonds leads to rapid depopulation of the lowest excited singlet state via two competing mechanisms: proton transfer and enhanced internal conversion. The experimental results are rationalized by calculations which include specific and nonspecific solvent effects.
Źródło:
Acta Physica Polonica A; 2007, 112, S; S-105-S-120
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Urbachs Rule in Undoped and Co Doped $(80-x)Sb_2O_3-20Na_2O-xWO_3$ Glasses
Autorzy:
Petkova, P.
Soltani, M.
Petkov, S.
Nedkov, V.
Powiązania:
https://bibliotekanauki.pl/articles/1490939.pdf
Data publikacji:
2012-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.70.Ce
78.20.Ci
78.30.-j
Opis:
We have analyzed the Co influence on the absorption spectra of $(80-x)Sb_2O_3-20Na_2O-xWO_3$ glasses in the Urbach rule region at room temperature. We present the comparison between Co and $WO_3$ manifestation in the spectral region 2.64-3.14 eV. The spectral characteristics of "crystalline" and "glassy" Urbach's rule are also calculated.
Źródło:
Acta Physica Polonica A; 2012, 121, 1; 152-154
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Physical Characterization of $Sb_2O_3-M_2O-MoO_3$ (M~= Li,~K) New Glasses
Autorzy:
Soltani, M.
Hamzaoui, M.
Houhou, S.
Touiri, H.
Bediar, L.
Ghemri, A.
Petkova, P.
Powiązania:
https://bibliotekanauki.pl/articles/1399699.pdf
Data publikacji:
2013-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.70.Ce
78.20.Ci
78.30.-j
Opis:
New heavy metal oxide glasses involving $Sb_2O_3$ have been investigated. By using classical routes (melting-casting), glasses synthesized in silica crucibles were obtained in the combination of ternary systems $Sb_2O_3-M_2CO_3-MoO_3$ (M = Li and K). Characteristic temperatures such as glass transition $T_{g}$, and onset of the crystallization $T_{x}$, have been measured using differential scanning calorimeter. Ultrasonic velocities were measured by using pulse echo method to determine the elastics parameters, such as elastic modules (E, G, K, L). Other physical properties were measured, such as density and optical transmission window in far infrared spectra using KBr pellets. Influence of composition on these physico-chemical properties is discussed and correlated to the glass structure.
Źródło:
Acta Physica Polonica A; 2013, 123, 2; 227-229
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spectroscopic Properties of Cu Doped $(80-x)Sb_2O_3-20Li_2O-xMoO_3$ Glasses
Autorzy:
Petkova, P.
Touiri, H.
Soltani, M.
Powiązania:
https://bibliotekanauki.pl/articles/1399682.pdf
Data publikacji:
2013-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Be
71.23.Cq
78.20.-e
Opis:
The antimony oxide as part of the heavy metal oxide glasses is attractive to researchers in recent years. The new antimony oxide glasses have been successfully synthesized using silica crucible in the ternary system for undoped and doped $(80-x)Sb_2O_3-20Li_2O-xMoO_3$ (x = 20, 30 mol.%) doped with 0.1 mol.% $CuO_2$. The optical characterization in the visible spectral region has been carried out on the doped glasses. The role of the Jahn-Teller effect in Cu doped glasses is determined and the electron transitions in these cations have been determined.
Źródło:
Acta Physica Polonica A; 2013, 123, 2; 205-206
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Network Properties of Ureasil-Based Polymer Matrixes for Construction of Amperometric Biosensors as Probed by PALS and Swelling Experiments
Autorzy:
Kavetskyy, T.
Šauša, O.
Čechová, K.
Švajdlenková, H.
Mat'ko, I.
Petkova, T.
Boev, V.
Ilcheva, V.
Smutok, O.
Kukhazh, Y.
Gonchar, M.
Powiązania:
https://bibliotekanauki.pl/articles/1033906.pdf
Data publikacji:
2017-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Lg
81.07.Pr
78.70.Bj
61.25.hp
Opis:
Network properties of ureasil-based polymer matrixes suitable for construction of amperometric biosensors were probed by positron annihilation lifetime spectroscopy and swelling experiments. Temperature dependences of the ortho-positronium (o-Ps) lifetimes and their relative intensities were measured in a temperature range of 15-350 K. Glass transition temperatures and expansion coefficients of microscopical free-volume for the investigated polymers were determined. Differences in network behavior for the aged samples and the effect of chalcogenide (As₂S₃) particles on the free volume of ureasil network were observed. Swelling experiments using ethyl alcohol showed that the structure of the aged sample network had less swelling ability for the pure ureasil as well as composite. This suggests that the one of factors influencing swelling is the change of the basic ureasil network due to ageing. It is supposed that the network properties obtained by positron annihilation lifetime spectroscopy and swelling experiments could be very helpful to understand better the bio-functionality of the constructed biosensor based on the ureasil-chalcogenide glass composite.
Źródło:
Acta Physica Polonica A; 2017, 132, 5; 1515-1518
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Iodine supplementation activates folliculogenesis in rabbit ovary
Autorzy:
Abadjieva, D.
Petkova, M.
Grigorova, S.
Kistanova, E.
Powiązania:
https://bibliotekanauki.pl/articles/2087684.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ovary
growing rabbits
growth-differentiation factor 9
iodine supplement
Źródło:
Polish Journal of Veterinary Sciences; 2018, 21, 3; 559-566
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-6 z 6

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