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Wyszukujesz frazę "Selim, F." wg kryterium: Autor


Wyświetlanie 1-4 z 4
Tytuł:
Developing New Routine for Processing Two-Dimensional Coincidence Doppler Energy Spectra and Evaluation of Electron Subsystem Properties in Metals
Autorzy:
Stepanov, P.
Stepanov, S.
Byakov, V.
Selim, F.
Powiązania:
https://bibliotekanauki.pl/articles/1033257.pdf
Data publikacji:
2017-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
Positron annihilation
Doppler broadening
metals
core electrons
Opis:
A digital coincidence Doppler broadening (CDB) spectrometer consisting of two HPGe detectors is assembled; the energy resolution of each detector is 1.1 keV at energies near the annihilation line. Two desktop applications for CDB spectra processing are developed. TLIST Processor converts two-dimensional CDB spectra into one-dimensional spectra. Another tool SW Calculator deconvolutes the experimental CDB spectra into contributions from positron annihilation with valence, core and conduction band electrons. The program estimates the energies of the corresponding electrons and evaluates S and W parameters of the CDB spectra.
Źródło:
Acta Physica Polonica A; 2017, 132, 5; 1628-1633
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Gamma Induced Positron Annihilation: History, Current, and Future Developments
Autorzy:
Selim, F.
Powiązania:
https://bibliotekanauki.pl/articles/1030020.pdf
Data publikacji:
2017-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
gamma induced positron spectroscopy
positron transient measurements
thermal neutron capture
proton capture
electron accelerator
Van de Graaff accelerator
Opis:
Positron annihilation spectroscopy is often performed using radioactive sources for bulk measurements or positron beams for depth resolved measurements. Both have many advantages and great capabilities for a variety of applications. In the recent history, we have shown that positron annihilation spectroscopy can be carried out directly using high energy photons without the need for positron source or positron beam. This approach brings unique capabilities for some specific applications and promotes the use of positron annihilation spectroscopy in new areas of materials science and probably in industrial applications. Some of the important applications include developing new nondestructive highly penetrating sensitive probe for structural and engineering materials. It can also greatly advance positron applications in bulk semiconductors, electronic and photonic materials as well as in polymers, ceramics, and liquids. The recently developed γ-induced positron spectroscopy in HZDR in Dresden provides an example of an excellent facility for many of these applications. When incorporated with pulsed accelerators, γ-induced positron annihilation spectroscopy may trigger novel studies of transient states in matter and explore several solid-state processes that take place on short time scale. In this article I will review the history and development of the technique and its incorporation in a wide range of accelerators including table top electron accelerators, pulsed electron accelerators, and Van de Graaff accelerators. Then I will introduce a design for a new γ-induced positron annihilation spectroscopy facility based on using small nuclear research reactors or neutron generators. The paper presents all the possible approaches for γ-induced positron annihilation spectroscopy and discusses its potential and limitations to guide the efforts in further development of the technique and illustrate the unique aspects that the technique can bring to positron science and applications.
Źródło:
Acta Physica Polonica A; 2017, 132, 5; 1450-1455
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Physicochemical study of dye removal using electro-coagulation-flotation process
Autorzy:
El-Hosiny, F. I.
Abdel-Khalek, M. A.
Selim, K. A.
Osama, I.
Powiązania:
https://bibliotekanauki.pl/articles/109865.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
electro-flotation
electrocoagulation
dyes
wastewater
kinetics
thermodynamics
Opis:
The performance of electro-flotation with aluminum electrodes for the removal of different dyes from synthetic aqueous solutions and real wastewater was studied. Parameters affecting the electro-coagulation-flotation process, such as pH, initial dye concentration, treatment time and temperature were investigated. The maximum dye removal from synthetic solutions was achieved at pH 7. The order of the dye removals is nonionic>cationic>anionic. The removal process follows pseudo first-order kinetics and the adsorption follows both physical and chemical adsorptions which is exothermic. Negative values of entropy change, ΔS°, and Gibbs free energy change, ΔG°, indicate that this adsorption process is spontaneous and less favorable at high temperatures. Treatment of a real wastewater from textile dyeing factory showed that the removal efficiency was ranging between 92-99% for all constituents. The energy consumption is 0.0167 kWh/dm3.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 2; 321-333
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Positron Lifetime Measurements of Vacancy Defects in Complex Oxides
Autorzy:
Varney, C.
Selim, F.
Powiązania:
https://bibliotekanauki.pl/articles/1196120.pdf
Data publikacji:
2014-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Bj
78.20.-e
81.40.Tv
Opis:
Native defects in complex oxides play a crucial role in determining their optical, electrical, and magnetic properties and it is difficult to identify and characterize them. Positron lifetime spectroscopy is a powerful technique to study vacancy defects; however its application to complex oxides has been limited. In this work we apply positron lifetime spectroscopy to study open volume defects in rare earth doped yttrium aluminum garnet (YAG) complex oxides grown in argon atmosphere. In YAG single crystals, positron lifetime measurements identified isolated aluminum vacancies and complexes of aluminum vacancy and neighbor oxygen vacancies. Thermoluminescence measurements were also performed to elucidate the interaction between trapping defects and luminescence centers. By combining positron lifetime and thermoluminescence, both the defect type and its effect on the optical properties of YAG crystals were revealed.
Źródło:
Acta Physica Polonica A; 2014, 125, 3; 764-766
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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