scholarly journals A STUDY ON THE 2% PdO/Al2O3 BY MEANS OF FREE POSITRON ANNIHILATION TECHNIQUE IN THE SOLID SURFACE LAYER

1992 ◽  
Vol 41 (2) ◽  
pp. 288
Author(s):  
SHI ZHI-KANG ◽  
HUANG CUN-PING
Keyword(s):  
Surface Layer ◽  
Positron Annihilation ◽  
Solid Surface ◽  
Free Positron

Sensitivity of positron-annihilation-induced Auger-electron spectroscopy to the top surface layer

1990 ◽  
Vol 41 (1) ◽  
pp. 799-802 ◽  
Author(s):  
David Mehl ◽  
A. R. Köymen ◽  
Kjeld O. Jensen ◽  
Fred Gotwald ◽  
Alex Weiss
Keyword(s):  
Surface Layer ◽  
Auger Electron Spectroscopy ◽  
Positron Annihilation ◽  
Electron Spectroscopy ◽  
Auger Electron

Positron annihilation in methane gas

1970 ◽  
Vol 48 (24) ◽  
pp. 2984-2990 ◽  
Author(s):  
P. M. Smith ◽  
D. A. L. Paul
Keyword(s):  
Positron Annihilation ◽  
Standard Error ◽  
Room Temperature ◽  
Annihilation Rate ◽  
Effective Number ◽  
Gas Density ◽  
Methane Gas ◽  
Free Positron

The annihilation of positrons in methane gas at room temperature has been measured at pressures below 2 atm. The annihilation rate for the free positron component is proportional to the gas density and corresponds to an effective number of electrons per molecule taking part in annihilation, Zeff = 139.6 ± 1.0 (standard error). The quenching of orthopositronium corresponds to 1Zeff = 0.57 ± 0.07. Resonance annihilation is discussed in a general way.

scholarly journals Rayleigh-wave coupling to atmospheric compression waves*

1952 ◽  
Vol 42 (2) ◽  
pp. 135-144
Author(s):  
W. S. Jardetzky ◽  
Frank Press
Keyword(s):  
Surface Layer ◽  
Rayleigh Wave ◽  
Numerical Computation ◽  
Group Velocity ◽  
Solid Surface ◽  
Rayleigh Waves ◽  
Wave Coupling ◽  
Compressional Waves ◽  
Compression Waves ◽  
Additional Branch

Abstract The theory of dispersive Rayleigh waves coupled to atmospheric compressional waves is derived for the case of a solid surface layer. Numerical computation of phase and group velocity curves indicates that an additional branch may be introduced to the dispersion curves as a result of air coupling. Amplitudes of waves propagated according to the various branches are briefly discussed.

scholarly journals Динамическая неустойчивость поверхности твердых тел под нагрузкой

2018 ◽  
Vol 60 (7) ◽  
pp. 1334
Author(s):  
Ю.А. Хон ◽  
H. Zapolsky ◽  
П.П. Каминский ◽  
А.Н. Пономарев
Keyword(s):  
Surface Layer ◽  
Electron Density ◽  
Solid Surface ◽  
Large Amplitude ◽  
Dynamic Instability ◽  
Interatomic Interaction

AbstractThe mechanism of dynamic instability of a solid surface under a load, determined by perturbations of the electron density and the change in the interatomic interaction, is considered. This instability is manifested upon the excitation of dynamic displacements of atoms in the surface layer, which can lead to formation of finite-lifetime structures in the form of waves with a large amplitude. Such structures were earlier observed experimentally on a stretched germanium (111) surface.

scholarly journals Analysis of Surface Properties of Nickel Alloy Elements Exposed to Impulse Shot Peening with the Use of Positron Annihilation

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7328
Author(s):  
Agnieszka Skoczylas ◽  
Kazimierz Zaleski ◽  
Radosław Zaleski ◽  
Marek Gorgol
Keyword(s):  
Surface Layer ◽  
Positron Annihilation ◽  
Nickel Alloy ◽  
Shot Peening ◽  
Positron Lifetime ◽  
Experimental Studies ◽  
Maximum Increase ◽  
Small Surface ◽  
The Mean ◽  
The Impact

The paper presents the results of experimental studies on the impact of impulse shot peening parameters on surface roughness (Sa, Sz, Sp, Sv), surface layer microhardness, and the mean positron lifetime (τmean). In the study, samples made of the Inconel 718 nickel alloy were subjected to impulse shot peening on an originally designed stand. The variable factors of the experiment included the impact energy, the diameter of the peening element, and the number of impacts per unit area. The impulse shot peening resulted in changes in the surface structure and an increase in surface layer microhardness. After the application of impulse shot peening, the analyzed roughness parameters increased in relation to post-milling values. An increase in microhardness was obtained, i.e., from 27 HV 0.05 to 108 HV 0.05 at the surface, while the maximum increase the microhardness occur at the depth from 0.04 mm to 0.08 mm. The changes in the physical properties of the surface layer were accompanied by an increase in the mean positron lifetime τmean. This is probably related to the increased positron annihilation in point defects. In the case of small surface deformations, the increase in microhardness was accompanied by a much lower increase in τmean, which may indicate a different course of changes in the defect structure consisting mainly in modification of the dislocation system. The dependent variables were subjected to ANOVA analysis of variance (it was one-factor analysis), and the effect of independent variables was evaluated using post-hoc tests (Tukey test).

Time of flight spectrometer for background-free positron annihilation induced Auger electron spectroscopy

2016 ◽  
Vol 87 (3) ◽  
pp. 035114 ◽  
Author(s):  
S. Mukherjee ◽  
K. Shastry ◽  
C. V. Anto ◽  
P. V. Joglekar ◽  
M. P. Nadesalingam ◽  
...  
Keyword(s):  
Auger Electron Spectroscopy ◽  
Positron Annihilation ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
Time Of Flight ◽  
Free Positron

Existence of a solid surface layer in liquid solutions

1975 ◽  
Vol 35 (2) ◽  
pp. 214-217 ◽  
Author(s):  
C. De Simone ◽  
B. Maraviglia
Keyword(s):  
Surface Layer ◽  
Solid Surface ◽  
Liquid Solutions

Cu gettering in Si cavities observed by Positron Annihilation Doppler Broadening

2000 ◽  
Vol 647 ◽  
Author(s):  
H. Schut ◽  
A. van Veen ◽  
S.W.H. Eijt
Keyword(s):  
Surface Layer ◽  
Positron Annihilation ◽  
Internal Surface ◽  
Positron Beam ◽  
Implantation Dose ◽  
Doppler Broadening ◽  
Higher Doses ◽  
Cluster Points

AbstractIn this study we present the results of Positron Beam Annihilation (PBA) experiments on the gettering of copper in Cz-Si implanted with 33 keV He+ ions with doses ranging from 0.5 to 3× 1016cm−2 followed by an anneal treatment at 1100 K under N2 ambient. For the higher doses this yields a sub-surface layer containing nanometer sized cavities. Copper is introduced into these cavities by diffusing from the backside of the wafer at 1000 K, again under N2 ambient. Mapping of the S and W Doppler broadening parameters, with the implantation dose as running parameter, shows the formation of cavities. After the Cu in-diffusion the change in the values of the characteristic S-W cluster points clearly demonstrates the arrival of Cu at the internal surface of the cavities.

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