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Wyszukujesz frazę "positron lifetime spectroscopy" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
Principles of positron porosimetry
Autorzy:
Zaleski, R.
Powiązania:
https://bibliotekanauki.pl/articles/146520.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
porous materials
positron annihilation lifetime spectroscopy (PALS)
positronium
extended Tao-Eldrup model
Opis:
The paper deals with positron porosimetry (PP), which is based on positron annihilation lifetime spectroscopy (PALS). The numerical analysis of positron lifetime spectra for PP is more demanding than in most of other applications of PALS. The resulting intensity distributions of ortho-positronium (o-Ps) lifetimes are interpreted in terms of the extended Tao-Eldrup (ETE) model, which provides the dependence between the o-Ps lifetime and pore size. Additionally, the relation between the intensity of an o-Ps component and the pore volume allows obtaining pore size distribution (PSD). The value of the empirical parameter Δ, which is dependent on material, can be estimated from the temperature dependence of an o-Ps lifetime. The most unique feature of PP among other techniques that allow determination of PSDs is its ability to perform measurements in almost any conditions. This makes this method suitable for various in situ studies. In this review article, both the capabilities and the limitations of PP are discussed. The methods to overcome some of the limitations are presented.
Źródło:
Nukleonika; 2015, 60, No. 4, part 1; 795-800
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ortho-positronium migration in mesopores of MCM-41, MSF and SBA-3
Autorzy:
Zaleski, R.
Błażewicz, A.
Kierys, A.
Powiązania:
https://bibliotekanauki.pl/articles/147955.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
nitrogen adsorption/desorption
porous materials
positron annihilation lifetime spectroscopy (PALS)
positronium migration
Opis:
Three materials: MCM-41, MSF and SBA-3 with a very similar pore diameter but different lengths of cylindrical pores were investigated using the nitrogen sorption method and positron annihilation lifetime spectroscopy. The size of primary pores and interparticle spaces obtained by both methods is similar. However, volume ratios between the discussed kinds of pores found by the above-mentioned methods differ significantly. Such discrepancy is the result of both ortho-positronium migration and the inaccessibility of the pores for nitrogen. Comparing the results of nitrogen sorption and positron annihilation lifetime spectroscopy allows us to estimate that connectivity between the primary pores and the interparticle spaces is the highest in MCM-41 and lowest in SBA-3.
Źródło:
Nukleonika; 2013, 58, 1; 235-240
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Positron annihilation lifetime spectroscopy study of roller burnished magnesium alloy
Autorzy:
Zaleski, R.
Zaleski, K.
Gorgol, M.
Powiązania:
https://bibliotekanauki.pl/articles/146650.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
AZ91HP magnesium alloy
defects
positron lifetime annihilation spectroscopy (PALS)
roller burnishing
Vickers hardness test
Opis:
The effect of roller burnishing on Vickers’ hardness and positron lifetimes in the AZ91HP magnesium alloy was studied. The microhardness increases with an increase in the burnishing force and with a decrease in the feed. The comparison of various methods of analysis of positron annihilation lifetime (PAL) spectra allowed identification of two components, which are related to solute-vacancy complexes and vacancy clusters, respectively. It was found that the increase in microhardness was related to the increase in the concentration of vacancy clusters.
Źródło:
Nukleonika; 2015, 60, No. 4, part 1; 789-794
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Positron annihilation lifetime spectroscopy study of thermal processing and rehydration of dry leek (Allium porrum L.)
Autorzy:
Zaleski, R.
Wawryszczuk, J.
Sobczak, K.
Powiązania:
https://bibliotekanauki.pl/articles/146309.pdf
Data publikacji:
2010
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
positron annihilation
lifetime spectroscopy
food processing
rehydration
leek (Allium porrum L.)
Opis:
New application of positron annihilation lifetime spectroscopy (PALS) to development of food processing techniques is tested. Dehydrated leeks were an object of the study. Three experiments were performed consisting of evacuating air and volatile compounds from the sample, applying thermal treatment and rehydrating the sample. Distinct changes in positron lifetime spectra allowed the monitoring of alterations in the sample structure. The most likely origin of the particular components present in the spectra was able to be proposed from these data. Changes of the components were ascribed to the various processes occurring in the samples.
Źródło:
Nukleonika; 2010, 55, 1; 73-78
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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