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Wyszukujesz frazę "Ahmad, E." wg kryterium: Autor


Wyświetlanie 1-4 z 4
Tytuł:
On Theoretical Study of Magnetic Behavior of Diamond Doped with Transition Metals
Autorzy:
Hussain, F.
Ullah, M.
Ullah, H.
Rashid, M.
Imran, M.
Ahmad, E.
Powiązania:
https://bibliotekanauki.pl/articles/1399279.pdf
Data publikacji:
2015-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.10.Kt
75.10.Pq
75.30.Hx
Opis:
We study the magnetic behavior of the diamond system. In this system diamond bulk is involved which is doped with different transition metals, namely Cu, Cd, Hg, and Zn. The VASP code is employed for all calculations which are based on density functional theory. The substitutional point defects is introduced in the diamond bulk and occupied by the transition metals. Results exhibit that all transition metals show ferromagnetism behavior and Cu is a good advocate of conductivity among all transition metals. The range of magnetic moments is 2.89, 1.99, 1.96, and 1.80 $μ_{B}$ per Cu, Cd, Hg, and Zn atom in diamond bulk, respectively. Strong magnetic behavior points out that these materials could be used for spintronics.
Źródło:
Acta Physica Polonica A; 2015, 127, 3; 823-826
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of the Effect of Boron Concentration on Magnetic and Structural Properties of $Nd_{7.5}Pr_{2.5}Fe_{90-x}B_x$ Melt-Spun Alloys
Autorzy:
Siddique, M.
Ahmad, I.
Kanwal, M.
Ahmed, E.
Powiązania:
https://bibliotekanauki.pl/articles/1401887.pdf
Data publikacji:
2015-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.80.+y
75.50.-y
61.43.-j
61.05.C-
Opis:
The Mössbauer spectroscopy and X-ray diffraction techniques have been used to investigate the effect of boron concentration on the structural and magnetic properties of as-quenched and heat-treated melt-spun alloys $Nd_{7.5}Pr_{2.5}Fe_{90-x}B_x$ (x=6, 8, 10) produced by melt-spinning technique. X-ray diffraction and Mössbauer spectroscopy results indicate that as-prepared samples are completely amorphous in nature. The X-ray diffraction patterns of samples heat-treated at 700°C are indexed as $Fe_{3}B,$ $\alpha-Fe,$ $(NdPr)_{2}Fe_{14}B$ and $Fe_{23}B_{6}$ phases. The Mössbauer spectra of heat-treated samples are very complex and constituted a number of sextets and a quadrupole doublet. Two main phases are $(NdPr)_{2}Fe_{14}B$ hard and $t-Fe_{3}B$ soft magnetic phases while $\alpha-Fe$ and $Nd_{23}Fe_{6}$ are detected as minor phases. The average internal magnetic field decreases with the increase of boron content; more sharply in as-prepared and comparatively slowly in heat-treated samples. The X-ray diffraction and Mössbauer spectroscopy results are in good agreement with each other.
Źródło:
Acta Physica Polonica A; 2015, 128, 3; 353-357
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental Analysis of Titanium Dioxide Synthesis from Synthetic Rutile Waste using a Moderate Acid Concentration and Temperature
Autorzy:
Ahmad Mukifza, H.
Awang, H.
Yusof, S.
Farid, E.
Powiązania:
https://bibliotekanauki.pl/articles/1031724.pdf
Data publikacji:
2017-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
synthetic rutile
titanium dioxide
caustic hydrothermal
sodium titanate
Opis:
The present study is to clarify the present influences of acid concentration and temperature of caustic hydrothermal method on extracting the titanium dioxide (TiO₂) from synthetic rutile waste. In this experimental work, the caustic hydrothermal method comprises two processes: a decomposition and the sulphate process. The extracted titanium is characterized by using a electron dispersive X-ray spectroscopy to specify its chemical composition, field emission scanning electron microscope to determine the morphology and particle size, and lastly it is the X-ray diffraction to analyse the crystallinity of extracted titanium. In this study, we found that both acid concentration and temperature affected the TiO₂ growth while the calcination process could improve the crystallinity of extracted titanium.
Źródło:
Acta Physica Polonica A; 2017, 132, 3; 833-835
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Computational Study of the Ozonolysis of Phenanthrene
Autorzy:
Almatarneh, M.
Al-Shamaileh, E.
Ahmad, Z.
Abu-Saleh, A.A.
Elayan, I.
Powiązania:
https://bibliotekanauki.pl/articles/1031212.pdf
Data publikacji:
2017-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
Ozonolysis of Phenanthrene
Primary Ozonide
Criegee Intermediate
Opis:
A computational study of the ozonolysis of phenanthrene has been carried out using DFT methods (B3LYP and M06-2X). The reaction mechanism for the ozonolysis was studied in both gas phase and in solution, using the polarizable continuum solvation model. The structures for all proposed reaction mechanisms were optimized using M06-2X and B3LYP methods with 6-31G(d), 6-31+G(d), and 6-31G(2df,p) basis sets. In solution, all structures were optimized using B3LYP/6-31+G(d,p) and polarizable continuum solvation model. Six different mechanistic pathways were explored for the ozonolysis of phenanthrene that forms aldehyde compounds. The activation energy of the formation of the primary ozonide intermediate in pathway A is 13 kJ mol¯¹ in the polarizable continuum model with the B3LYP/6-31+G(d,p) method. This reaction is followed by a dissociation into a zwitterionic Criegee intermediate with an activation energy of 76 kJ mol¯¹ in polarizable continuum model with B3LYP/6-31+G(d,p). Furthermore, the nucleophilic addition reactions of methanol to the Criegee intermediate have been studied along two pathways, B1 and B2. The water-mediated mechanism for pathways B2 and C2, where the water molecule acts as a mediator through a 1,5-proton shift, dropped the activation barriers by 18 and 26 kJ mol¯¹, respectively, based on B3LYP/6-31G(2df,p) method. The solvation model (polarizable continuum) reduces the energy barriers for all pathways except for the reaction of methanol with the Criegee intermediate. This study provides an insight into understanding the mechanism of transformation of this pollutant into non-toxic compounds.
Źródło:
Acta Physica Polonica A; 2017, 132, 3; 1149-1156
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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