Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

Wyszukujesz frazę "DR" wg kryterium: Temat


Wyświetlanie 1-8 z 8
Tytuł:
Revision of the Model of Formation of Radiolytic Products in Aqueous Solutions
Autorzy:
Stepanov, S. V.
Byakov, V. M.
Powiązania:
https://bibliotekanauki.pl/articles/2042192.pdf
Data publikacji:
2005-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.80.Fe
36.10.Dr
78.70.Bj
Opis:
Mathematical model of formation of radiolytic products (e$\text{}_{aq}^{-}$, H, OH, H$\text{}_{2}$, H$\text{}_{3}$O$\text{}^{+}$, OH$\text{}^{-}$, Ps) in water is developed. It takes into account (1) reactions between dissolved scavengers of thermalized and hydrated electrons as well as epithermal ones; (2) ambipolar diffusion expansion of the intratrack species; (3) additional channels of Ps and H$\text{}_{2}$ formation due to appearance of weakly trapped electrons. Good agreement is obtained with experimental data on kinetics of accumulation of the products in pure water and their concentration variations in aqueous solutions.
Źródło:
Acta Physica Polonica A; 2005, 107, 4; 651-660
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Primary Chemical Reactions Induced by Transformation of Radioactive Nuclei in Solids at Low Temperatures. Investigation by Means of the Emission Mössbauer and Positron Spectroscopies
Autorzy:
Byakov, V. M.
Kulikov, L. A.
Perfil'ev, Y. D.
Stepanov, S. V.
Powiązania:
https://bibliotekanauki.pl/articles/2043320.pdf
Data publikacji:
2005-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.80.Fe
36.10.Dr
78.70.Bj
Opis:
A set of early chemical reactions in grapes of ionization (blobs) arising in tracks of fast electrons and positrons in liquids as well as formed by the Auger electrons in frozen aqueous media around decaying Mössbauer $\text{}^{57}$Co or $\text{}^{119m}$Sn nuclei is suggested. The mechanism predicts a correlated variation of the formation probabilities of intrablob final products, namely Fe$\text{}^{2+}$-Fe$\text{}^{3+}$ or Sn$\text{}^{2+}$-Sn$\text{}^{4+}$ ions, positronium atom and molecular hydrogen with variation of temperature, degree of crystallinity, concentration of electron scavengers. These correlations indicate on similarity of chemical processes as in blobs created by $\text{}^{57}$Co and $\text{}^{119m}$Sn after their decay as well as in blobs produced in tracks of fast positrons and electrons.
Źródło:
Acta Physica Polonica A; 2005, 107, 5; 792-798
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Positron Irradiation on Positronium Formation in n-Alkanes
Autorzy:
Pietrow, M.
Zgardzińska, B.
Powiązania:
https://bibliotekanauki.pl/articles/2047152.pdf
Data publikacji:
2006-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
36.10.Dr
61.80.Fe
78.70.Bj
Opis:
Positronium formation probability was investigated as a function of irradiation time and temperature for some long-chain saturated hydrocarbons (alkanes). Intensity of ortho-positronium component in the lifetime spectrum depends on the concentration of trapped excess electrons, but also on concentration of radicals and ions acting as electron scavengers. The results indicate the existence of two kinds of electron traps; those which are not emptied by thermal treatment disappear after several days of positron irradiation.
Źródło:
Acta Physica Polonica A; 2006, 110, 5; 641-648
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental Verification of the Blob Model and Delayed Formation of Ps
Autorzy:
Dauwe, C.
Van Waeyenberge, B.
De Baerdemaeker, J.
Powiązania:
https://bibliotekanauki.pl/articles/2042183.pdf
Data publikacji:
2005-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
36.10.Dr
78.70.Bj
61.80.Fe
82.35.Lr
Opis:
Stepanov and Byakov's blob model for the formation of positronium can be considered as an extension of the spur model. However, it offers many extra possibilities and is more sound from the radiation chemistry point of view. A full coding of this model leads to non-exponential lifetime spectra, and standard multi-component analysis is no longer adequate for materials such as polymers. Age momentum correlation experiments were performed on linear PMMA at different temperatures and were analyzed with the non-exponential blob model. We show the adequacy of this model, and moreover an alternative explanation for the young-age broadening and delayed formation of positronium.
Źródło:
Acta Physica Polonica A; 2005, 107, 4; 623-628
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ortho-Positronium in Alkanes under High Pressure
Autorzy:
Goworek, T.
Zgardzińska, B.
Powiązania:
https://bibliotekanauki.pl/articles/1812529.pdf
Data publikacji:
2008-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
36.10.Dr
61.80.Fe
71.60.+z
78.70.Bj
Opis:
Phase transitions in n-alkanes were observed by using the positron annihilation lifetime method. In the case of alkanes, application of pressure is equivalent to temperature lowering (1 K corresponds to ≈4 MPa). When argon at high pressure penetrates the sample one observes a non-monotonous dependence of the melting point on pressure. This effect is observed also in even-numbered alkanes, in which there is no rotator phase.
Źródło:
Acta Physica Polonica A; 2008, 113, 5; 1379-1383
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Positronium in Phase IV and Rotator Phase of Long-Chain Alkanes
Autorzy:
Zgardzińska, B.
Goworek, T.
Powiązania:
https://bibliotekanauki.pl/articles/1812555.pdf
Data publikacji:
2008-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
36.10.Dr
61.80.Fe
71.60.+z
78.70.Bj
Opis:
Ortho-positronium lifetime and intensity was measured as a function of temperature and pressure for some n-alkanes in which so-called "phase IV" appears. This phase is characterized by slightly increased ortho-positronium lifetime compared to low-temperature phases. It was found that the effect of quenching positronium by light does not appear in all phases from phase IV upwards. The lifetime in the rotator phases becomes equal to that in liquids, and only the change of positronium formation intensity allows to detect the solid-liquid transition in positron lifetime measurements.
Źródło:
Acta Physica Polonica A; 2008, 113, 5; 1551-1555
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Role of Trapped and Solvated Electrons in Ps Formation
Autorzy:
Stepanov, S. V.
Byakov, V. M.
He, C.
Hirade, T.
Mikhin, K. V.
Powiązania:
https://bibliotekanauki.pl/articles/2042190.pdf
Data publikacji:
2005-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.80.Fe
36.10.Dr
78.70.Bj
82.35.Lr
Opis:
Role of trapped and solvated electrons in Ps formation is discussed. Combination of thermalized positron with such electrons is possible from the viewpoint of the energy balance and may results in Ps formation. This process proceeds during all e$\text{}^{+}$ lifetime in matter. Fitting of raw experimental e$\text{}^{+}$ - e$\text{}^{-}$ annihilation spectra has to be based on an adequate physical input, which often leads to necessity of nonexponential deconvolution of the spectra. We have interpreted the Ps formation data in polyethylene, ethylene-methylmethacrylate and polymethylmethacrylate in dark and in light vs. time of the measurement and temperature. Parameters characterized accumulation of trapped electrons and their recombination with counter ions and positrons are obtained.
Źródło:
Acta Physica Polonica A; 2005, 107, 4; 642-650
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ortho-Positronium in Some n-Alkanes; Influence of Temperature and Pressure
Autorzy:
Zgardzińska, B.
Pietrow, M.
Goworek, T.
Wawryszczuk, J.
Powiązania:
https://bibliotekanauki.pl/articles/2047166.pdf
Data publikacji:
2006-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
36.10.Dr
61.80.Fe
71.60.+z
78.70.Bj
Opis:
Positron lifetime spectra were measured for a series of odd-numbered n-alkanes from C$\text{}_{11}$H$\text{}_{24}$ to C$\text{}_{19}$H$\text{}_{40}$ as a function of temperature and pressure. The ortho-Ps lifetimes in the rotator phase and the increase in intensity at the transition to that phase can be explained by location of Ps in the vicinity of kink-type conformers. The relation between o-Ps lifetime and molecule length can be described in the framework of extended Tao-Eldrup model. One can eliminate the effect of intensity rise in time by sample illumination or by application of high pressure. A decrease in temperature by 1 K is equivalent to an increase in pressure by about 4 MPa.
Źródło:
Acta Physica Polonica A; 2006, 110, 5; 747-753
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

    Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies