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Water-Vapor Sorption Processes in Nanoporous MgO-Al(2)O(3) Ceramics: the PAL Spectroscopy Study

The water-vapor sorption processes in nanoporous MgO-Al(2)O(3) ceramics are studied with positron annihilation lifetime (PAL) spectroscopy employing positron trapping and positronium (Ps)-decaying modes. It is demonstrated that the longest-lived components in the four-term reconstructed PAL spectra...

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Autores principales: Klym, Halyna, Ingram, Adam, Shpotyuk, Oleh, Hadzaman, Ivan, Solntsev, Viacheslav
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Springer US 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4783312/
https://www.ncbi.nlm.nih.gov/pubmed/26956602
http://dx.doi.org/10.1186/s11671-016-1352-6
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author Klym, Halyna
Ingram, Adam
Shpotyuk, Oleh
Hadzaman, Ivan
Solntsev, Viacheslav
author_facet Klym, Halyna
Ingram, Adam
Shpotyuk, Oleh
Hadzaman, Ivan
Solntsev, Viacheslav
author_sort Klym, Halyna
collection PubMed
description The water-vapor sorption processes in nanoporous MgO-Al(2)O(3) ceramics are studied with positron annihilation lifetime (PAL) spectroscopy employing positron trapping and positronium (Ps)-decaying modes. It is demonstrated that the longest-lived components in the four-term reconstructed PAL spectra with characteristic lifetimes near 2 and 60–70 ns can be, respectively, attributed to ortho-positronium (o-Ps) traps in nanopores with 0.3- and 1.5–1.8-nm radii. The first o-Ps decaying process includes “pick-off” annihilation in the “bubbles” of liquid water, while the second is based on o-Ps interaction with physisorbed water molecules at the walls of the pores. In addition, the water vapor modifies structural defects located at the grain boundaries in a vicinity of pores, this process being accompanied by void fragmentation during water adsorption and agglomeration during water desorption after drying.
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spelling pubmed-47833122016-04-09 Water-Vapor Sorption Processes in Nanoporous MgO-Al(2)O(3) Ceramics: the PAL Spectroscopy Study Klym, Halyna Ingram, Adam Shpotyuk, Oleh Hadzaman, Ivan Solntsev, Viacheslav Nanoscale Res Lett Nano Express The water-vapor sorption processes in nanoporous MgO-Al(2)O(3) ceramics are studied with positron annihilation lifetime (PAL) spectroscopy employing positron trapping and positronium (Ps)-decaying modes. It is demonstrated that the longest-lived components in the four-term reconstructed PAL spectra with characteristic lifetimes near 2 and 60–70 ns can be, respectively, attributed to ortho-positronium (o-Ps) traps in nanopores with 0.3- and 1.5–1.8-nm radii. The first o-Ps decaying process includes “pick-off” annihilation in the “bubbles” of liquid water, while the second is based on o-Ps interaction with physisorbed water molecules at the walls of the pores. In addition, the water vapor modifies structural defects located at the grain boundaries in a vicinity of pores, this process being accompanied by void fragmentation during water adsorption and agglomeration during water desorption after drying. Springer US 2016-03-09 /pmc/articles/PMC4783312/ /pubmed/26956602 http://dx.doi.org/10.1186/s11671-016-1352-6 Text en © Klym et al. 2016 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
spellingShingle Nano Express
Klym, Halyna
Ingram, Adam
Shpotyuk, Oleh
Hadzaman, Ivan
Solntsev, Viacheslav
Water-Vapor Sorption Processes in Nanoporous MgO-Al(2)O(3) Ceramics: the PAL Spectroscopy Study
title Water-Vapor Sorption Processes in Nanoporous MgO-Al(2)O(3) Ceramics: the PAL Spectroscopy Study
title_full Water-Vapor Sorption Processes in Nanoporous MgO-Al(2)O(3) Ceramics: the PAL Spectroscopy Study
title_fullStr Water-Vapor Sorption Processes in Nanoporous MgO-Al(2)O(3) Ceramics: the PAL Spectroscopy Study
title_full_unstemmed Water-Vapor Sorption Processes in Nanoporous MgO-Al(2)O(3) Ceramics: the PAL Spectroscopy Study
title_short Water-Vapor Sorption Processes in Nanoporous MgO-Al(2)O(3) Ceramics: the PAL Spectroscopy Study
title_sort water-vapor sorption processes in nanoporous mgo-al(2)o(3) ceramics: the pal spectroscopy study
topic Nano Express
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4783312/
https://www.ncbi.nlm.nih.gov/pubmed/26956602
http://dx.doi.org/10.1186/s11671-016-1352-6
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