Autor: C̆iz̆ek, J. - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Thermal Development of Free Volumes in Nafion Membrane
Autorzy:: Melikhova, O.
Čížek, J.
Košinová, L.
Hruška, P.
Powiązania:: https://bibliotekanauki.pl/articles/1033913.pdf
Data publikacji:: 2017-11
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 78.70.Bj
61.66.Hq
82.35.Lr
Opis:: In this work we employed positron lifetime spectroscopy for investigation of the thermal development of free volumes in H⁺ Nafion membrane over a broad range of temperatures from -150 to 150°C. Positron lifetime studies were combined with differential scanning calorimetry. Size distribution of free volumes was determined from ortho-positronium contribution to positron lifetime spectra. Our investigations revealed that the mean size of free volume holes strongly increases with temperature. On the other hand, the width of the size distribution and the positronium yield decreases with temperature. Transition temperatures corresponding to a change in the slope of the temperature dependence of ortho-positronium lifetime were identified. Results of positron lifetime spectroscopy agree well with the curve obtained by differential scanning calorimetry.
Źródło:: Acta Physica Polonica A; 2017, 132, 5; 1538-1542
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 2.

Tytuł:: Precipitation Effects in Mg-Zn Alloys Studied by Positron Annihilation and Hardness Testing
Autorzy:: Hruška, P.
Čížek, J.
Vlček, M.
Melikhova, O.
Procházka, I.
Powiązania:: https://bibliotekanauki.pl/articles/1196079.pdf
Data publikacji:: 2014-03
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 78.70.Bj
61.72.J-
Opis:: In the present work positron annihilation spectroscopy combined with Vickers hardness testing were employed in order to investigate precipitation effects in Mg-Zn alloys. It was found that incoherent precipitates of a metastable Zn-rich phase formed in the samples isochronally annealed above 200C cause hardening of the alloy.
Źródło:: Acta Physica Polonica A; 2014, 125, 3; 718-721
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 3.

Tytuł:: Investigation of Precipitation Effects in Mg-Tb and Mg-Tb-Nd Alloys
Autorzy:: Vlček, M.
Čížek, J.
Melikhova, O.
Hruška, P.
Procházka, I.
Powiązania:: https://bibliotekanauki.pl/articles/1196115.pdf
Data publikacji:: 2014-03
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 78.70.Bj
61.72.J-
Opis:: Investigation of precipitation effects in solution treated Mg-Tb and Mg-Tb-Nd alloy was performed. Solution treated alloys were compared with samples deformed by high pressure torsion to examine influence of deformation on precipitation effects. Dislocations present in samples processed by high pressure torsion can serve as diffusion channels for atoms and also as nucleation sites for precipitates. Therefore precipitation of some phases in high pressure torsion deformed samples was observed at lower temperatures than in solution treated ones.
Źródło:: Acta Physica Polonica A; 2014, 125, 3; 744-747
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 4.

Tytuł:: Characterization of Defects in Titanium Created by Hydrogen Charging
Autorzy:: Hruška, P.
Čížek, J.
Knapp, J.
Melikhova, O.
Havela, L.
Mašková, S.
Lukáč, F.
Powiązania:: https://bibliotekanauki.pl/articles/1033958.pdf
Data publikacji:: 2017-11
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 78.70.Bj
61.72.-y
Opis:: Hydrogen interaction with vacancies in α-Ti was investigated employing positron lifetime spectroscopy combined with ab initio theoretical modeling of vacancy-hydrogen complexes. Ab initio modeling revealed that multiple hydrogen atoms up to 7 can be trapped at vacancies in the α-Ti lattice. Trapped H atoms are located close to the nearest neighbor tetrahedral sites around the centre of vacancy. Lifetimes of positrons trapped at vacancies associated with various numbers of hydrogen atoms were calculated. Positron lifetime measurement of H-loaded α-Ti samples revealed that phase transition into the hydride phase introduced dislocations. Vacancies were created by H loading as well and agglomerated into small vacancy clusters.
Źródło:: Acta Physica Polonica A; 2017, 132, 5; 1606-1610
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 5.

Tytuł:: Positronium Formation in Nanostructured Metals
Autorzy:: Čížek, J.
Melikhova, O.
Hruška, P.
Vlček, M.
Anwand, W.
Liedke, M.
Novotný, M.
Bulíř, J.
Powiązania:: https://bibliotekanauki.pl/articles/1033937.pdf
Data publikacji:: 2017-11
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 78.70.Bj
41.75.Fr
36.10.Dr
Opis:: Positronium formation in Au films was studied using a magnetically guided continuous slow positron beam with variable energy. Black Au film with porous morphology was compared with conventional smooth Au film. In the smooth Au film positronium is formed on the film surface only. The black Au film exhibits porous sub-surface region containing micro-cavities interconnected with surface. Positronium is formed on inner surfaces of micro-cavities in the sub-surface region and travels through interconnected cavities towards the surface. 3-γ annihilation of ortho-positronium leaves a clear signature in two-dimensional coincidence Doppler broadening spectra. Measures of 3-γ annihilation contribution calculated from single γ-ray and coincidence Doppler broadening spectra were calculated and compared.
Źródło:: Acta Physica Polonica A; 2017, 132, 5; 1579-1584
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

Artykuł

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