Liquid Crystalline Polyurethanes Studied by Positron Annihilation Method

Structure of dislocations in Al and Fe as studied by positron-annihilation spectroscopy.

Vacancy profile in reverse osmosis membranes studied by positron annihilation lifetime measurements and molecular dynamics simulations

The positron annihilation technique using a slow positron beam can be used for the study of the vacancy profiles in typical reverse osmosis (RO) membranes. In this study, the vacancy profile in the polyamide membrane that exhibits a high permselectivity between ions and water was studied using the positron annihilation technique and molecular dynamics simulations. Orthopositronium (o-Ps) lifeti...

Effect of carbon on copper precipitation in deformed Fe-based alloys studied by positron annihilation spectroscopy

The role of deformation-induced defects and carbon addition on the copper precipitation during aging at 550 o C is investigated in high-purity Fe-Cu-B-N-C alloy samples by Coincidence Doppler Broadening. In samples with 0% and 8% cold pre-strain, the influence of tensile pre-deformation on the precipitation kinetics of copper is studied. The deformationinduced defects are found to enhance the C...

Vacancy-impurity pairs in relaxed Si1−xGex layers studied by positron annihilation spectroscopy

Positron annihilation spectroscopy was applied to study relaxed P-doped n-type and undoped Si1−xGex layers with x up to 0.30. The as-grown SiGe layers were found to be defect free and annihilation parameters in a random SiGe alloy could be represented as superpositions of annihilations in bulk Si and Ge. A 2 MeV proton irradiation with a 1.6 1015 cm−2 fluence was used to produce saturated posit...

Titanium-Rich Precipitate Evolution in Vanadium-based Alloys Studied by TEM and Positron Annihilation Spectroscopy