Results 191 to 200 of about 42,514 (244)

Positron lifetime spectroscopy of lithium tetraborate Li2B4O7 glass

Journal of Non-Crystalline Solids, 2017
Abstract Free-volume structure of glassy lithium tetraborate Li2B4O7 is studied as compared with isocompositional crystal using positron annihilation lifetime spectroscopy in mixed positron-trapping and Ps-decaying modes exploring three-term decomposed positron lifetime spectra.
O. Shpotyuk, V. Adamiv, I. Teslyuk, A. Ingram   +3 more
openaire   +2 more sources

Porosimetry of zeolitic imidazolate frameworks using positron annihilation lifetime spectroscopy

Microporous and Mesoporous Materials, 2022
J. Mor, P. Utpalla, J. Bahadur, D. Sen, S.K. Sharma   +4 more
openaire   +2 more sources

Positron lifetime spectroscopy in copper

Journal of Physics F: Metal Physics, 1986
The temperature dependence of positron annihilation in copper was investigated by measuring the positron lifetime between 20 and 1070 degrees C. A high-resolution lifetime spectrometer (FWHM 170 ps) with a stability better than +or-1.5 ps over a period of four weeks was used.
T Hehenkamp, T Kurschat, W Luhr-Tanck
openaire   +1 more source

Positron annihilation lifetime spectroscopy of annealed tungsten

Kerntechnik, 2022
Abstract Three samples of 99.97% pure rolled tungsten were annealed at 700 °C, 1000 °C, and 1400 °C in a vacuum of about 10−6 mbar for 1 h. Then the effects of annealing were investigated. For this purpose, defects and their structure in the three annealed samples and the as-received sample, were studied, characterized, and compared by ...
Mahnaz Torabi, Omidreza Kakuee, Samad Sobhanian, Mohammad Kouhi   +3 more
openaire   +1 more source

Observation of the Recrystallization Process in Pure Nb and Zr Using Positron Lifetime Spectroscopy and XRD Techniques

physica status solidi (b), 2018
Results of research on the recrystallization of highly deformed Nb and Zr with the use of positron lifetime spectroscopy and XRD measurements are presented here.
J. Dryzek, M. Wróbel
semanticscholar   +1 more source

The Influence of Free Volume Determined by Positron Annihilation Lifetime Spectroscopy (PALS) on Gas Permeability of Cellulose Nanocrystals Films.

ACS Applied Materials and Interfaces, 2020
Cellulose nanocrystals (CNCs) are of increasing interest for packaging applications because of their biodegradability, low cost, high crystallinity and high aspect ratio. The objective of this study was to use positron annihilation lifetime spectroscopy (
M. Nuruddin, Reaz A. Chowdhury, N. Lopez-Perez, Francisco Montes, J. Youngblood, J. Howarter   +5 more
semanticscholar   +1 more source

Positron lifetime spectroscopy of vitreous B2O3

Journal of Non-Crystalline Solids, 2004
Abstract A comparison is made of the structural data obtained by positron lifetime spectroscopy (PLS) for vitreous B 2 O 3 (v-B 2 O 3 ) and crystalline B 2 O 3 (c-B 2 O 3 ). Samples of v-B 2 O 3 were dried by holding the melt at 1350 K to reduce residual OH groups.
B.L. Shivachev, I.P. Mincov, E.P. Kashchieva, Y.B. Dimitriev, R. Smith, T. Troev   +5 more
openaire   +1 more source

Positron lifetime spectroscopy in nanocrystalline iron

Physics Letters A, 1987
Abstract First positron annihilation measurements were performed on nanocrystalline iron specimens which are polycrystals with very small crystallite size (5–10 nm). The lifetimes τ 1 = 180 ± 15 ps, τ 2 = 360 ± 30 ps and long-lived components between 1 and 4 ns are attributed to vacancy-size free volumes in the crystallite interfaces, to ...
H.E. Schaefer, R. Würschum
openaire   +1 more source

Single shot positron annihilation lifetime spectroscopy

Applied Physics Letters, 2006
Recent developments in positron trapping technology have made possible experimentation with dense interacting positronium gases. Along with these capabilities comes a need for suitable measurement techniques, and accordingly we have developed a method to measure positronium lifetimes from a single intense burst of positrons.
D. B. Cassidy, S. H. M. Deng, H. K. M. Tanaka, A. P. Mills   +3 more
openaire   +1 more source