Full-text resources of PSJD and other databases are now available in the new Library of Science.
Visit https://bibliotekanauki.pl
Preferences help
Polish version English version Language
enabled [disable] Abstract
Number of results

Results found: 14

Number of results on page
first rewind previous Page / 1 next fast forward last

Search results

help Sort By:

help Limit search:
first rewind previous Page / 1 next fast forward last
1
Publication available in full text mode
Content available

Melting Process of the Sn-45 wt.% In and Sn-77 wt.% In Alloys as Viewed by Positron Annihilation

100%
Rudzińska W., Szuszkiewicz M.
Acta Physica Polonica A
|
2006
|
vol. 110
|
issue 5
701-708
EN
The temperature dependences of the positron annihilation parameters F and R were determined for Sn-45 wt.% In and Sn-77 wt.% In alloys. The obtained results enabled to verify the vacancy and the quasicrystalline models of the melting process. It was found that for metals transforming into the liquid state from the structures different than the close packed structure, the melting transition are hardly explainable in terms of the vacancy model of melting. The strong trapping of positrons in metallic liquids is an indication of the presence of microvoids (vacancy clusters) or microcrystals containing defects more immense than vacancies. The share of these positron trapping centers in the volume of metallic liquids is constant or decreases with increasing temperature. The obtained results demonstrate the particular applicability of the positron annihilation method for studies of defect kinetics in metallic liquids.
2
Content available remote

Investigation of the Solid-Liquid Phase Transition for SnIn Alloys by the Positron Annihilation Method

81%
Chabik S., Rudzińska W., Szuszkiewicz M., Szymański C.
Acta Physica Polonica A
|
1993
|
vol. 83
|
issue 3
261-265
EN
The monovacancy formation energy in Sn-17 wt.% In and Sn-32 wt.% In was determined on the basis of the temperature dependence of the peak counting rate for these alloys. A sudden increase in the counting rate was observed between solidus and liquidus temperature. This phenomenon is connected with the formation of large defects acting as positron traps.
3
Content available remote

Positron Annihilation in Steel Samples Deformed by Uniaxial Tension

81%
Rudzińska W., Szuszkiewicz M., Bujnarowski G., Kluza A.
Acta Physica Polonica A
|
2008
|
vol. 113
|
issue 5
1507-1510
EN
Angular distributions of the positron annihilation quanta were measured for steel ST2 SAL samples deformed by uniaxial tension up to different deformation degrees. The dependences of the S parameter on the relative elongation of the samples are presented. The positron annihilation data for steel are compared with the results obtained previously for polycrystalline iron samples deformed by uniaxial tension up to different deformation degrees in the proportionality and limited proportionality regions.
4
Content available remote

Test Measurements of Modernized Version of Two-Detector Doppler Spectrometer

81%
Baranowski A., Kostrzewa M., Szuszkiewicz M.
|
|
vol. 95
|
issue 4
439-447
EN
Basing on the electronic analogue modules in adding and subtracting branches of pulses, a modernized two-detector Doppler spectrometer has been constructed using only one multichannel analyser. Doppler spectra for Al, Ni, Ag have been measured. ACARFIT computer program was used to compare the Doppler and angular correlation of annihilation radiation results.
5
Content available remote

Positron Annihilation in Solid and Liquid Bi_{40}Sn_{60} Alloy

81%
Chabik S., Rudzińska W., Szuszkiewicz M., Szymański C.
|
|
vol. 95
|
issue 4
479-482
EN
The peak counting rate, F(T), for Bi_{40}Sn_{60} alloy in the temperature range from room temperature to 400°C was measured in three consecutive heating-cooling runs. Significant changes in F(T) were observed in the temperature interval between the solidus and liquidus temperature. The magnitude of these anomalies systematically diminishes in consecutive heating-cooling runs. Noticeable changes of values of F(T) parameter in the liquid alloy were observed, too. These effects were connected with trapping of positrons at the grain boundaries-defects and in the short-range ordered regions in the liquid alloy. Also microscopic structure of sample before and after measurements cycles was observed.
6
Publication available in full text mode
Content available

Positron Annihilation in Defected Monocrystalline Gold Samples

81%
Pająk J., Rudzińska W., Szuszkiewicz M., Garłowska M.
Acta Physica Polonica A
|
2005
|
vol. 107
|
issue 5
848-851
EN
Angular distribution of the positron annihilation quanta was measured for monocrystalline gold samples, oriented in (110) and (111) directions. The samples were deformed by elongation for different deformation degrees. The S and W parameters as a function of deformation degree of the sample were determined. It was found that the dynamics of the dislocations and vacancy generation during the sliding of some crystallographic planes, depends on the crystallographic direction.
7
Publication available in full text mode
Content available

Investigation of the Absorption of Annihilation Quanta in Solid and Liquid Ga and BiSn Alloy

81%
Kluza A., Rudzińska W., Szuszkiewicz M.
Acta Physica Polonica A
|
2001
|
vol. 99
|
issue 3-4
407-413
EN
Absorption of positron annihilation quanta in Ga and Bi_{40}Sn_{60} alloy in the solid and the liquid phase was investigated. It was found that the mechanism of absorption of annihilation quanta changes on passing from the solid to the liquid state. Results of measurements for Ga and Bi_{40}Sn_{60} alloy show that for metals changing their density at the melting point the photopeak profiles are modified: their centers of gravity in liquid phase are displaced with respect to those in the solid phase and the number of counts under the photopeak changes, too.
8
Publication available in full text mode
Content available

Studying of Nickel Alloys with 1 at.% of Ge, Zn, In, Zr and Pb by Positron Annihilation Methods

81%
Baranowski A., Kostrzewa M., Szuszkiewicz M.
Acta Physica Polonica A
|
2001
|
vol. 99
|
issue 3-4
329-336
EN
The measurements of cold rolled nickel alloys with 1 at.% of Ge, Zn, In, Zr, Pb and additionally Ti and Sb by positron lifetime and Doppler broadening techniques have been done. Monovacancies were a dominating type of defects in the alloys. The authors of the present paper connect the differences between the annihilation parameters of the investigated samples with the existence of the vacancy-impurity atom pairs. A direct proportionality between the vacancy lifetime and the product of vacancy-impurity binding energy and atomic radius of impurity atom has been found.
9
Content available remote

Measurements of Positrons Lifetimes in Corroded Nickel

81%
Pietrzak R., Szatanik R., Szuszkiewicz M.
|
|
vol. 95
|
issue 4
647-651
EN
An attempt was undertaken at making use of a technique of taking measurements of lifetimes of positrons emitted from ^{22}Na source to investigate corroded nickel. It was found that after corrosion in HCl vapours mean positrons lifetime, the second component of positrons lifetimes as well as its intensity rise along with the corrosion time.
10
Content available remote

Positron Annihilation in Deformed and Hydrogenated Pd-23%atcu Alloy

81%
Pająk J., Szatanik R., Szuszkiewicz M.
|
|
vol. 95
|
issue 4
637-640
EN
Peak coincidence counting rate and positron lifetime spectra for deformed by cold-rolling, and annealed by four hours in the temperature 973 K, hydrogen free and hydrogenated PdCu with 23% Cu samples, in the temperature range from room temperature to about 720 K were measured. It was found that hydrogen improved to tempered samples creates defects that are annealed to the temperature about 525 K. In the cold-rolled up to deformation degree of 50% samples, hydrogen is trapped at defects, probably vacancies, forming H-V complexes, that become disappearing in the vicinity of the temperature at 350 K.
11
Publication available in full text mode
Content available

Positron Annihilation with Electrons of Admixture Atoms in Some Binary Nickel Alloys

81%
Baranowski A., Kostrzewa M., Szuszkiewicz M.
|
EN
Weighted difference curves have been shortly presented as a proper tool allowing to analyze in another way two-detector Doppler spectra regarding positron annihilation with admixture electrons in some nickel alloys. The analysis of low and middle momentum parts of Doppler spectra for investigated alloys reflects the annihilation of positrons with admixture electrons. There is no distinct signal of annihilations with admixture electrons from the positron lifetime data for well-annealed samples.
12
Publication available in full text mode
Content available

Positron Lifetime in Hostaphan

81%
Kostrzewa M., Bujnarowski G., Kluza A., Szuszkiewicz M.
Acta Physica Polonica A
|
2006
|
vol. 110
|
issue 5
615-620
EN
Positron lifetime measurements in hostaphan RNK, used for encapsulation of ^{22}Na positron sources, were performed. It was found that the parameter of positron lifetime spectra in hostaphan RNK differ markedly from those for other forms of polyethylene terephthalate. The maximum penetration depth of positrons from RNK hostaphan amounts 0.42 mm. The information gained in the present study is of great importance for experimenters using hostaphan RNK for encapsulation of positron sources.
13
Publication available in full text mode
Content available

Positron Annihilation in Polycrystalline Metals Deformed by Uniaxial Tension

71%
Rudzińska W., Pająk J., Szuszkiewicz M., Bujnarowski G., Kluza A.
Acta Physica Polonica A
|
2005
|
vol. 107
|
issue 5
857-863
EN
Angular distributions of the positron annihilation quanta were measured for polycrystalline samples deformed by uniaxial tension up to different deformation degrees. The S parameter as a function of the W parameter was determined. The data obtained for samples elongated up to different elongation degrees indicate that in the proportionality and limited proportionality regions the changes in the physical properties of samples are governed mainly by generation of vacancies and formation and kinetics of transformations of vacancy clusters occurring first of all on the grains of monocrystallites. In the region of plastic deformations the dominant defects are dislocations and vacancies and their aggregates generated due to the formation and movement of the dislocation of the primary and secondary slip. The positron annihilation data are corroborated by the results of the resistometric and tensometric measurements in the proportionality and limited proportionality regions.
14
Publication available in full text mode
Content available

Positron Annihilation in Metals Defected by Action of the Tensile Force

71%
Rudzińska W., Pająk J., Szuszkiewicz M., Bujnarowski G., Kluza A.
Acta Physica Polonica A
|
2006
|
vol. 110
|
issue 5
691-699
EN
Results of experimental investigations of uniaxially elongated mono- and polycrystalline samples of several metals (Fe, Ta, Pd, Ag, and Au), performed using the positron annihilation methods, are reviewed. The dependences of the S-parameters and positron lifetimes on the relative elongation of the samples were presented. The data obtained for polycrystalline samples indicate that in the proportionality and limited proportionality regions the changes in the physical properties are governed mainly by generation of vacancies and by kinetics of formation and transformations of vacancy clusters occurring first of all on the grain boundaries of monocrystallites. In the region of plastic deformations the dominant defects are dislocations and vacancies and their aggregates generated due to the formation and movement of the dislocations of the primary and secondary slip. In the case of monocrystalline samples it was found that the dynamics of the dislocations and vacancy generation during the sliding of some crystallographic planes depends on the crystallographic direction.
first rewind previous Page / 1 next fast forward last
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.