Free‐volume and pore size distributions determined by numerical Laplace inversion of positron annihilation lifetime data

1991 ◽  
Vol 70 (9) ◽  
pp. 4665-4670 ◽  
Author(s):  
Roger B. Gregory
Keyword(s):  
Pore Size ◽  
Positron Annihilation ◽  
Free Volume ◽  
Lifetime Data ◽  
Size Distributions ◽  
Laplace Inversion ◽  
Positron Annihilation Lifetime ◽  
Numerical Laplace Inversion ◽  
Pore Size Distributions

Influence of Atmospheric Gases Present in the Pores of MCM-41 on Lifetime of Ortho-Positronium

2010 ◽  
Vol 666 ◽  
pp. 123-128 ◽  
Author(s):  
Radosław Zaleski ◽  
Michał Sokół
Keyword(s):  
Porous Material ◽  
Pore Size ◽  
Reasonable Agreement ◽  
Size Distributions ◽  
Spectroscopy Data ◽  
Atmospheric Gases ◽  
Positron Annihilation Lifetime ◽  
Pore Size Distributions ◽  
Mcm 41 ◽  
Quenching By Oxygen

The modification of the extended Tao-Eldrup model accounting ortho-positronium quenching in air is presented. Taking into account quenching by oxygen molecules adsorbed on the surface of porous material gives reasonable agreement between results of the model and the experimental positron annihilation lifetime spectroscopy data. Pore size distributions calculated using this model from the spectra for MCM 41 mesoporous sieve obtained in air, oxygen or vacuum are compared and discussed taking into account effect of ortho-positronium migration from small open pores to the larger ones. The rates of ortho-positronium quenching by air (47.2 µs-1 MPa 1), oxygen (220 µs-1 MPa-1) or nitrogen (1.7 µs-1 MPa-1) obtained from pressure dependences of the lifetimes observed in MCM 41 agree reasonably with the experimental results of other authors, if the correction for oxygen adsorbed on the surface is applied.

Some Problems of the Free Volume Studies in Porous Polymers Using Positron Annihilation and Auxiliary Techniques

2008 ◽  
Vol 607 ◽  
pp. 155-160
Author(s):  
Victor P. Shantarovich ◽  
V.W. Gustov ◽  
Y.P. Yampolskii ◽  
E.V. Belousova ◽  
A.V. Polyakova ◽  
...  
Keyword(s):  
Specific Surface ◽  
Positron Annihilation ◽  
Free Volume ◽  
Large Scale ◽  
Porous Polymers ◽  
Size Distributions ◽  
Membrane Materials ◽  
Positron Annihilation Lifetime ◽  
Polymer Sorbents ◽  
Number Of Publications

Membrane materials and polymer sorbents, polymers with highly developed free volume and specific surface, are of great technical importance. Positron annihilation lifetime (PAL) studies of these materials and some additional experiments give a chance to learn about the character of size distributions of elementary free volumes (EFV) of these materials. Particularly to answer the question whether the distributions of o-Ps lifetimes are of Gaussian type, as it is suggested in a number of publications, or they have some asymmetry or even some multi-component character, also to check some ideas on the ways of o-Ps trapping. In this aspect, large scale of o-Ps lifetimes (pore sizes) in these materials is very important, since enables comparison with the results of auxiliary techniques.

CHARACTERIZATION OF PORE SIZE DISTRIBUTIONS USING NON-NEWTONIAN FLUIDS

2020 ◽  
Author(s):  
Scott C. Hauswirth ◽  
◽  
Majdi Abou Najm ◽  
Christelle Basset
Keyword(s):  
Pore Size ◽  
Newtonian Fluids ◽  
Size Distributions ◽  
Pore Size Distributions

Preparation of P(GMA-co-EGDMA) Monolithic Columns with Adjustable Porous Properties

2014 ◽  
Vol 936 ◽  
pp. 942-949 ◽  
Author(s):  
Hao Tian Zhang ◽  
Qiu Yu Zhang ◽  
Bao Liang Zhang ◽  
Chun Mei Li
Keyword(s):  
Pore Size ◽  
Monolithic Column ◽  
Organic Polymer ◽  
Monolithic Columns ◽  
Size Distributions ◽  
Notable Effect ◽  
Pore Size Distributions ◽  
Porous Properties ◽  
Glass Tubes ◽  
First Time

Porous properties have notable effect on separating effect of organic polymer-based monolithic column. Different applications of monolithic columns require tailored pore size distributions. On account of that, P(GMA-co-EGDMA) monolithic columns were prepared with novel ternary porogenic agents. Glass tubes was chosen as polymerization mold. Moreover, factors influencing the inner pore morphology, pore size and specific surface area were investigated systematically. The results showed that the increasing of the solubility of porogenic agents and the amount of crosslinker, the decreasing of the amount of porogenic agents and temperature rising all could give rise to the decreasing of pore size. Remarkably, the effect of initiator was studied for the first time. The results showed that amount of initiator had no remarkable influence on porous properties. By controlling effect factors, P(GMA-co-EGDMA) Monolithic Columns with pore size from dozens to thousands of nanometer, which can be applied in separation of molecules with different size.

Coal pore size distributions controlled by the coalification process: An experimental study of coals from the Junggar, Ordos and Qinshui basins in China

Fuel ◽  
2017 ◽  
Vol 206 ◽  
pp. 352-363 ◽  
Author(s):  
Yong Li ◽  
Cheng Zhang ◽  
Dazhen Tang ◽  
Quan Gan ◽  
Xinlei Niu ◽  
...  
Keyword(s):  
Experimental Study ◽  
Pore Size ◽  
Size Distributions ◽  
Pore Size Distributions
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