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Wyszukujesz frazę "61.72.Bb" wg kryterium: Temat


Tytuł:
Calculation of Lattice Relaxation in Some Substitutional Alloys Using a Green Function
Autorzy:
Das, S. K.
Datta Roy (Paul), S.
Powiązania:
https://bibliotekanauki.pl/articles/1995663.pdf
Data publikacji:
1999-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.Bb
61.82.Bg
Opis:
In this paper we calculate nearest neighbour relaxation in some dilute substitutional alloys using a lattice static Green function and the Morse potential function. Distant neighbour relaxation is calculated by invoking a continuum approximation. The potential parameters for the unlike interactions are calculated using simple interpolation formulae. Using the above relaxation, we calculate volume changes in the above alloys. It is observed that the simple model predicts values which are in reasonably good agreement with the experimental values in all cases. The calculated values are also compared with those obtained from the Vegard law. For Au-Ag alloy, our model reproduces both the correct sign and the magnitude of the volume change, whereas the Vegard law cannot even give the sign of the volume change. This shows the inherent strength of the present model.
Źródło:
Acta Physica Polonica A; 1999, 95, 3; 359-366
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Green Function Estimation of Correction to Vegards Law for isovalent Substitutional Defects in Alkali Halide Crystals
Autorzy:
Datta Roy (Paul), S.
Das, S. K.
Powiązania:
https://bibliotekanauki.pl/articles/2013286.pdf
Data publikacji:
2000-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.Bb
61.82.Bg
Opis:
A Green function method is developed for estimation of lattice parameter r(χ) of an AX-BX solid solution over entire composition range (χ=0 to 1). The r(χ) obtained in the present method is different from the value r$\text{}_{V}$(χ) suggested by Vegard's law. We estimated the deviation from Vegard's law, r(χ)-r$\text{}_{V}$(χ), over entire composition range for isovalent substitutional defect in alkali halide crystals. When compared to X-ray diffraction measurements, we find that the deviation is in correct direction, variation of r(χ) with χ is consistent with experiment and the overall agreement is fairly good considering the accuracy of the experiment.
Źródło:
Acta Physica Polonica A; 2000, 97, 4; 671-679
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evolution of Matrix-Twin Interfaces of (101̅2) Twin in Magnesium
Autorzy:
Ostapovets, A.
Serra, A.
Powiązania:
https://bibliotekanauki.pl/articles/1402119.pdf
Data publikacji:
2015-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.Bb
61.72.Mm
62.20.F-
Opis:
Recently, the presence of basal-prismatic interfaces in hexagonal close packed metals became subject of intensive investigation. We model the {101̅2} twin in magnesium bounded by two types of boundaries, i.e. {101̅2} interface and basal-prismatic facets. The migration of all boundary types is mediated by the motion of interfacial disconnections. It was shown that basal-prismatic interfaces play an important role in twin growth. The lengths of basal-prismatic facets remain constant during migration independently of the applied strain. In contrast, the {101̅2} interfaces increase their lengths during growth.
Źródło:
Acta Physica Polonica A; 2015, 128, 4; 661-663
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mould walls inclination and dendritic morphology of CMSX-4 blades airfoils
Autorzy:
Krawczyk, J.
Bogdanowicz, W.
Sieniawski, J.
Kubiak, K.
Powiązania:
https://bibliotekanauki.pl/articles/1075667.pdf
Data publikacji:
2016-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.70.+w
61.66.Dk
61.72.Bb
Opis:
The airfoils of single-crystalline turbine blades were studied. The blades made of industrial CMSX-4 superalloy were obtained by the Bridgman technique. Five different withdrawal rates (1-5 mm/min) were used. Series of as-cast samples were prepared by cutting the airfoils at different distances from the blade root. The metallographic sections, prepared for each cutting planes, were subjected to scanning electron microscopy observations and Laue diffraction studies. Macrostructure images of whole area of airfoil cross-sections were obtained by stitching several obtained SEM images. Morphology of dendrites in different area of cross-sections were analysed. The crystal orientation of each sample were determined by analysis of Laue pattern. It was found that the morphology of dendrites changes in the area, where the dendrite growth is limited by inclined mould walls.
Źródło:
Acta Physica Polonica A; 2016, 130, 4; 1100-1103
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Paramagnetic State of Hydrogen-Passivated Double-Donor Centers in Silicon
Autorzy:
Gregorkiewicz, T.
Zevenbergen, I. S.
Martynov, Yu. V.
Ammerlaan, C. A. J.
Powiązania:
https://bibliotekanauki.pl/articles/1933751.pdf
Data publikacji:
1995-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.30.Lh
61.72.Bb
76.70.Dx
Opis:
Hydrogenation of two double donor centers in silicon - substitutional sulfur and thermal donor - is studied by electron paramagnetic resonance and electron-nuclear double resonance. For both centers the existence of a new paramagnetic S = 1/2 state identified as the neutral charge state of the double donor passivated with a single hydrogen atom is concluded. The microscopic structure of such complexes is discussed.
Źródło:
Acta Physica Polonica A; 1995, 88, 4; 735-738
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Defects and Defect Reactions in Semiconductor Nitrides
Autorzy:
Van de Walle, C. G.
Neugebauer, J.
Stampfl, C.
McCluskey, M. D.
Johnson, N. M.
Powiązania:
https://bibliotekanauki.pl/articles/2011140.pdf
Data publikacji:
1999-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.Bb
61.72.Ji
61.82.Fk
71.55.Eq
Opis:
We report a comprehensive investigation of native point defects and impurities in GaN, AlN, and AlGaN alloys, with the goal of understanding doping limitations in nitride semiconductors. Unintentional incorporation of impurities (mainly oxygen) explains the tendency of nitride semiconductors to exhibit n-type conductivity. Silicon is the n-type dopant of choice; it remains shallow in AlGaN up to high Al content, while oxygen undergoes a DX transition. Experimental evidence for DX centers will be discussed. In p-type material, Mg doping is hindered by an increase in ionization energy with increasing Al content in AlGaN, and by nitrogen vacancies acting as compensating centers. Complex formation between magnesium and oxygen and between magnesium and nitrogen vacancies will be discussed.
Źródło:
Acta Physica Polonica A; 1999, 96, 5; 613-627
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase Field Modeling of the $Zn_{1-x}Cd_xO$ Solid Solutions
Autorzy:
Shtepliuk, I.
Podolskaia, N.
Lashkarev, G.
Powiązania:
https://bibliotekanauki.pl/articles/1375728.pdf
Data publikacji:
2014-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.60.My
05.70.Ln
61.72.Bb
61.72.Mm
Opis:
The analysis of spinodal decomposition in the $Zn_{1-x}Cd_xO$ ternary alloy was carried out by means of the nonlinear Cahn-Hilliard equation. Interaction parameter as a function of composition x was provided by valence force field simulations and was used in this analysis. The morphological patterns for the ternary alloys with different Cd content (x=5, 10, 50%) were experimentally obtained using the semi-implicit Fourier-spectral method. The simulated microstructure evolution $Zn_{0.95}Cd_{0.05}O$ demonstrates that the microstructure having a form of bicontinuous worm-like network is evolved with the progress of aging. An effect of the phase-field mobility and the gradient energy on the microstructure evolution of the $Zn_{1-x}Cd_xO$ alloys is discussed. It was found that the higher driving force for the decomposition in the higher Cd content film results in a higher decomposition rate revealed by the simulations. The temporal evolution of the simulated $Zn_{0.95}Cd_{0.05}O$ microstructure is in good agreement with experimental results, which have been obtained for this solid solution.
Źródło:
Acta Physica Polonica A; 2014, 126, 5; 1079-1082
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An ab initio Study of a Model of Single Wall GaN Nanotubes with Oxygen and Zinc as Impurities: Structural and Electronic Properties
Autorzy:
Rezouali, K.
Belkhir, M.
Powiązania:
https://bibliotekanauki.pl/articles/1813497.pdf
Data publikacji:
2008-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.46.Fg
61.72.Bb
73.61.Ey
73.61.Wp
Opis:
We report a comprehensive theoretical study of structural and electronic properties of substitutional oxygen and zinc contaminations in a model of single wall GaN nanotubes by means of ab initio supercell calculations. Our investigation yields many interesting results. The following ones deserve to be developed. Oxygen forms a shallow donor in the single wall GaN nanotubes as in bulk GaN polytypes. Its ionization energy is deeper than its counterpart in the bulk wurtzite GaN, so it can be a suitable n-type dopant in high temperature applications. Zinc is a relatively shallow acceptor at gallium site. It behaves as charge carrier trap at nitrogen site. The site preference of zinc impurity depends on the stoichiometry. Zinc at gallium site has small ionization energy, thus it would be an efficient p-dopant in GaN nanotubes unlike in bulk GaN polytypes.
Źródło:
Acta Physica Polonica A; 2008, 113, 2; 713-722
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical Studies of ESR Parameters and Local Lattice Structure of the Vanadate-Lithium-Borate Glasses
Autorzy:
Feng, W.
Zhao, M.
Li, T.
Zhang, X.
Xue, J.
Powiązania:
https://bibliotekanauki.pl/articles/1419845.pdf
Data publikacji:
2012-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.70.Ch
75.10.Dg
61.72.Bb
76.30.Fc
Opis:
Electron spin resonance spectral parameters of $V^{4+}$ ions in vanadate-lithium-borate glasses have been calculated by the crystal-field theory. The theoretical results are $g_{∥ }$ = 1.940, $g_{⊥}$ = 1.983 and $A_{∥ } = -175 \times 10^{-4} cm^{-1},$ $A_{⊥} = -65 \times 10^{-4} cm^{-1}$ which are good agreement with the experimental values ($g_{∥ }$ = 1.939(3), $g_{⊥}$ = 1.998(3) and $A_{∥ } = (170.6-176.4) \times 10^{-4} cm^{-1},$ $A_{⊥} = (61.3-71.4) \times 10^{-4} cm^{-1}$). In addition, the bond lengths of the local lattice structure are, respectively, $R_{∥ }$ = 1.5 Å and $R_{⊥}$ = 1.95 Å which have been shown to have a compressed tetrahedral geometry along the $C_4$ axis.
Źródło:
Acta Physica Polonica A; 2012, 122, 1; 167-169
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical Explanations of the Optical Band Positions and Local Structure for $Cu^{2+}$ Centers in $ZnO-Bi_{2}O_{3}-B_{2}O_{3}-CuO$ Glasses
Autorzy:
Yuan, M.
Powiązania:
https://bibliotekanauki.pl/articles/1377767.pdf
Data publikacji:
2014-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.Bb
75.10.Dg
76.30.-v
76.30.Fc
Opis:
The local structure, two optical band positions and three electronic spin resonance parameters for $Cu^{2+}$ centers at the tetragonally-distorted octahedral sites in $ZnO-Bi_2O_3-B_2O_3-CuO$ glasses are calculated from the high-order perturbation method based on the two-spin-orbit-parameter model, where the contributions from both the spin-orbit coupling parameters of central $d^{n}$ ion and ligand ion are included. The theoretical results are in good agreement with the experimental values. The calculations show that the high-order perturbation method based on the two-spin-orbit-parameter model is effective in the explanations of optical spectra, electronic spin resonance parameters and local distortion structure for $d^{9}$ ions in glasses.
Źródło:
Acta Physica Polonica A; 2014, 126, 6; 1293-1295
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigations of the Optical Band Positions and Spin-Hamiltonian Parameters for the Rhombic $VO^{2+}$ Complex in CsCl Crystal
Autorzy:
Fang, W.
Zheng, W.
Yang, D.
Tang, H.
Powiązania:
https://bibliotekanauki.pl/articles/1365269.pdf
Data publikacji:
2014-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.70.Ch
75.10.Dg
61.72.Bb
76.30.Fc
Opis:
The optical band positions and spin-Hamiltonian parameters (g factors $g_{i}$ and hyperfine structure constants $A_{i}$, where i=x, y, z) of the rhombic $VO^{2+}$ complex in CsCl crystal are calculated together from two theoretical methods. One is the complete diagonalization (of energy matrix) method and another is the perturbation theory method. The calculated results from the two methods coincide and are in reasonable agreement with the experimental values. So, both methods are effective in the explanations of optical and electron paramagnetic resonance (EPR) data for $d^1$ ions in crystals. The calculations also suggest that in $d^1$ rhombic octahedra the ground state is almost a pure | $d_{xy}$ ⟩ state. This point is different from that of conjugate $d^9$ (e.g., $Cu^{2+}$) ions in rhombic octahedra where the ground state should be an admixture of ground and first excited states.
Źródło:
Acta Physica Polonica A; 2014, 125, 5; 1206-1209
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Explanation of the Optical Spectra and Spin-Hamiltonian Parameters for Nickel(II) in Cadmium Bromide Crystal
Autorzy:
Gong, J.
Wang, L.
Feng, W.
Yang, X.
Zhang, F.
Powiązania:
https://bibliotekanauki.pl/articles/1493631.pdf
Data publikacji:
2011-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.70.Ch
75.10.Dg
61.72.Bb
76.30.Fc
Opis:
Based on crystal- and ligand-field theory, double-spin-orbital coupling approach was used to analyze the crystal-field energy levels and spin-Hamiltonian parameters of $Ni^{2+}$ ion at trigonal site in $CdBr_2$. The local lattice distortion (Δ R and $τ_{Ni^{2+}}$) is estimated from the crystal field parameters; the crystal field energy Hamiltonian was diagonalized in the full basis consisting of 45 wave functions of the $Ni^{2+}$ ion. Results of calculations are in good agreement with experimental data. The reasonableness of the theoretical results is discussed.
Źródło:
Acta Physica Polonica A; 2011, 120, 3; 497-500
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Influence of a Magnetic Field on the Formation of Corrosion Defects in Selected Metals and Steels, Analysed Using Positron Annihilation Method
Autorzy:
Pietrzak, R.
Szatanik, R.
Powiązania:
https://bibliotekanauki.pl/articles/1196102.pdf
Data publikacji:
2014-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Bj
61.72.Cc
82.45.Bb
Opis:
The method of positron lifetime measurement was used to analyse the influence of a magnetic field on the kinetics of corrosion defect formation in near-surface layers of iron, titanium as well as S20 and S0H18N9 steel grades. The listed metals, which belong to ferro- and paramagnetic materials, have different sensitivity to corrosion. It was found that not only the presence of a magnetic field, but also its direction influence the dimensions and the concentration of defects formed during corrosion.
Źródło:
Acta Physica Polonica A; 2014, 125, 3; 733-736
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Positron Annihilation in Corroded Steels St20 and St3S
Autorzy:
Pietrzak, R.
Smiatek, W.
Szatanik, R.
Powiązania:
https://bibliotekanauki.pl/articles/2047155.pdf
Data publikacji:
2006-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Bj
61.72.Cc
82.45.Bb
Opis:
The paper deals with examining the lifetimes of positrons emitted from $\text{}^{22}$Na source in corroded St20 and St3S steels. Influence of the method of defecting the sample surfaces on the spectrum of positron lifetimes was investigated. Influence of temperature of initial annealing of samples, plastic deformation, electrolytic hydrogenation and corrosion in HCl vapors on trapping positrons in the examined steels was also determined.
Źródło:
Acta Physica Polonica A; 2006, 110, 5; 667-676
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Influence of Magnetic Field on Annihilation of Positrons in Corroded Steel St-20
Autorzy:
Pietrzak, R.
Szatanik, R.
Jaworska, A.
Powiązania:
https://bibliotekanauki.pl/articles/2047156.pdf
Data publikacji:
2006-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Bj
61.72.Cc
82.45.Bb
Opis:
The positron lifetime in steel St-20 were determined before and following corrosion in HCl vapors. The influence of external magnetic field and remanent magnetization state on the parameters of the positron lifetime spectrum in the steel were investigated. It was found that the presence of magnetic field causes a decrease in the intensity of the component connected with annihilation of positrons in the close-to-the-surface lattice defects.
Źródło:
Acta Physica Polonica A; 2006, 110, 5; 677-681
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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