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Wyszukujesz frazę "K. W." wg kryterium: Autor


Tytuł:
Defect Study on Deformed Fe-Si Alloys by Positron Annihilation Techniques
Autorzy:
Chou, K. W.
De Baerdemaeker, J.
Peral, V.
Ruiz, D.
Houbaert, Y.
Segers, D.
Powiązania:
https://bibliotekanauki.pl/articles/2043321.pdf
Data publikacji:
2005-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.60.+z
78.70.Bj
Opis:
A set of Fe-Si samples with different Si content, varying from 0 to 7.6 wt.%, was investigated using positron annihilation spectroscopy. Different deformations were performed on these samples and the lineshape parameters of the annihilation line were measured in order to investigate the defects in the alloys. An exponential decay of the S-parameter in function of the time can be observed after deformation of the samples. The decay constant increases with increasing Si content. During the measurements of the samples with increasing Si content, the initiation of DO$\text{}_{3}$ structure can be seen above 5 wt.% of Si, as well as the decoration by impurities.
Źródło:
Acta Physica Polonica A; 2005, 107, 5; 799-804
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Properties of New York/New Jersey Harbor Sediments
Autorzy:
Jones, K. W.
Feng, H.
Stern, E. A.
Neuhäusler, U.
Osán, J.
Marinkovic, N.
Song, Z.
Powiązania:
https://bibliotekanauki.pl/articles/2044657.pdf
Data publikacji:
2006-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
89.60.-k
89.20.-a
Opis:
Sediments found in waterways around the world may contain toxic compounds of anthropogenic origin that can harm the environment and human health. As a result, it is often necessary to remove them and find disposal methods that are environmentally and economically acceptable. Here, we report on results obtained in an experimental program to characterize the nature of the sediment contamination. The objective was to gain a better understanding of the properties of the sediments to develop better methods for understanding the fate and transport of the contaminants and for improving methods for their removal from the sediments. Our investigations made use of X-ray facilities at the Brookhaven National Synchrotron Light Source and the European Synchrotron Radiation Facility at Grenoble, France. The experiments included: measurements of the microstructure of the sediments using computed microtomography, X-ray absorption, and fluorescence microscopy with resolutions as low as 0.2 micrometers to obtain information on the relationships of organic and mineral components of the sediments and on the distribution of contaminants on the surfaces of the sediment grains, investigation of functional groups of chemical compounds using X-ray absorption near-edge spectroscopy and Fourier transform infrared spectroscopy. Scanning electron microscopy and electron probe measurements were made to ascertain the morphology of the sediment surfaces and the distribution of metals on individual sediment grains.
Źródło:
Acta Physica Polonica A; 2006, 109, 3; 279-286
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Compensation Models in Chlorine Doped CdTe Based on Positron Annihilation and Photoluminescence Spectroscopy
Autorzy:
Stadler, W.
Hofmann, D. M.
Meyer, B. K.
Krause-Rehberg, R.
Polity, A.
Abgarjan, Th.
Salk, M.
Benz, K. W.
Azoulay, M.
Powiązania:
https://bibliotekanauki.pl/articles/1934007.pdf
Data publikacji:
1995-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.Gs
78.70.Bj
78.55.Et
Opis:
In this investigation positron annihilation, photoluminescence and electron paramagnetic resonance techniques are employed to gain insight in the compensation of CdTe doped with the halogen Cl. We will demonstrate that the high resistivity of CdTe:Cl cannot be explained by the interaction between the shallow effective mass type donor Cl on Te site and the doping induced shallow acceptor complex, a Cd vacancy paired off with a nearest-neighbour Cl atom (A centre). From electron paramagnetic resonance investigations we conclude that the mid gap trap, often detected by electrical methods in CdTe, is not the isolated Cd vacancy.
Źródło:
Acta Physica Polonica A; 1995, 88, 5; 921-924
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
2D Electron Gas in Non-Uniform Magnetic Fields
Autorzy:
Gallagher, B. L.
Kubrak, V.
Rushforth, A.
Neumann, A. C.
Edmonds, K. W.
Main, P. C.
Henini, M.
Marrows, C. H.
Hickey, B. J.
Thoms, S.
Dahlberg, D. E.
Powiązania:
https://bibliotekanauki.pl/articles/2014148.pdf
Data publikacji:
2000-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.50.Jt
73.20.Dx
73.23.Ad
73.50.Fq
Opis:
We present a review of some of our recent experimental work on hybrid ferromagnet/semiconductor devices in which 2D electrons propagate through magnetic barriers, periodic magnetic modulations, and random magnetic fields.
Źródło:
Acta Physica Polonica A; 2000, 98, 3; 217-230
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Lattice Deformation Studies in Silicon Implanted with High-Energy Protons
Autorzy:
Wieteska, K.
Dłużewska, K.
Wierzchowski, W.
Powiązania:
https://bibliotekanauki.pl/articles/1945258.pdf
Data publikacji:
1996-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.10.-i
61.80.-x
Opis:
The deformation of crystal lattice in silicon implanted with protons of energy 1.6-9 MeV was studied by means of X-ray topography and double-crystal rocking curve measurements. The samples were investigated as-implanted and after thermal and electron annealing. The surface relief of the implanted part of the crystal was also revealed with optical methods. As-implanted wafers exhibited spherical bending being convex at the implanted side. Thermal and electron annealing caused a dramatic increase in bending of the implanted part while the bending of the remaining part of the sample was reduced. A characteristic behaviour of a double-crystal topographic contrast in the annealed crystals was explained due to bending of the shot-through layer along the Gaussian profile.
Źródło:
Acta Physica Polonica A; 1996, 89, 3; 395-400
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Interference Fringes in Synchrotron Section Topography of Implanted Silicon with a Very Large Ion Range
Autorzy:
Wieteska, K.
Wierzchowski, W.
Graeff, W.
Dłużewska, K.
Powiązania:
https://bibliotekanauki.pl/articles/1964180.pdf
Data publikacji:
1997-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.10.-i
61.80.-x
Opis:
Silicon crystals implanted with 9 MeV protons to the dose of 5×10$\text{}^{17}$ cm$\text{}^{-2}$ were studied with X-ray topographic methods using both conventional and synchrotron radiation sources. After the implantation the crystals were thermally and electron annealed. The implantation produced large 600 μm thick shot-through layer while the total thickness of the samples was 1.6 mm. It was confirmed by means of double crystal topography that the whole crystal was elastically bent. The transmission section patterns revealed both parts of the implanted crystal separated by strong contrasts coming from the most damaged layer and distinct interference fringes which appeared on one side of the topograph only. The location of the fringes changed when the beam entered the other side of the sample. The mechanism of fringe formation was studied with numerical integration of the Takagi-Taupin equations, especially studying the intensity distribution in the diffraction plane. The simulations reproduced the location of the fringes in different geometries and indicate that they can be caused both by variable crystal curvature and variable ion dose.
Źródło:
Acta Physica Polonica A; 1997, 91, 5; 1021-1024
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase Separations in the Narrow-Bandwidth Limit of the Penson-Kolb-Hubbard Model at Zero Temperature
Autorzy:
Kapcia, K.
Czart, W.
Powiązania:
https://bibliotekanauki.pl/articles/1030443.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.10.Fd
71.10.Hf
74.20.-z
74.25.Dw
64.75.Gh
Opis:
In this work we study the ground state of the Penson-Kolb-Hubard model in the limit of narrow-bandwidth. We present phase diagrams of the model for fixed chemical potential and concentration (involving various phase separations). The results are derived within the Hartree-Fock approximation (HFA) in the narrow-bandwidth regime and compared with the exact ones in the atomic limit and the high-dimension regime. Our investigation reveals that the HFA can reconstruct the exact diagram at the ground state when the bandwidth approaches to zero.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 401-404
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Acoustic Pressure Radiated by a Vibrating Circular Plate within the Fraunhofer Zone of the Three-Wall Corner Region
Autorzy:
Szemela, K.
Rdzanek, W.
Powiązania:
https://bibliotekanauki.pl/articles/1490263.pdf
Data publikacji:
2012-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.20.Ks
43.20.Rz
43.40.+s
43.20.-f
43.20.+g
Opis:
The Neumann boundary value problem has been solved for the region bounded by the three perfect rigid infinite baffles arranged perpendicularly to one another. The harmonically vibrating clamped circular plate embedded in one of the baffles is the sound source. It has been assumed that the amplitude of the plate's transverse vibrations is small to use the linear Kelvin-Voigt theory. The Green function has been applied to obtain the asymptotic formulae describing the distribution of the acoustic pressure within the Fraunhofer zone. The analysis of sound radiation has been performed for some selected surface excitations and for some different plate's locations. The acoustic pressure distribution has been examined including the acoustic attenuation and the internal attenuation of the plate's material.
Źródło:
Acta Physica Polonica A; 2012, 121, 1A; A-100-A-109
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cole-Cole Plots for Linear and Nonlinear Dielectric Relaxation in Solutions of Rigid Highly Dipolar Symmetric-Top Molecules in Spherical Solvents
Autorzy:
Alexiewicz, W.
Grygiel, K.
Powiązania:
https://bibliotekanauki.pl/articles/1812032.pdf
Data publikacji:
2008-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.40.Jc
77.22.-d
77.22.Gm
Opis:
The graphical analysis of the influence of the rotational diffusion tensor anisotropy and the orientation of the permanent dipole moment on the linear and nonlinear dielectric relaxation is shown. The solution of Smoluchowski-Debye rotational diffusion equation for rigid, and noninteracting polar, symmetric-top molecules, in the "weak molecular reorientation approximation", was used. In order to highlight the influence of the symmetric shape of molecule, in comparison with classical, spherical-top Smoluchowski rotational diffusion, we present sets of Argand-type plots and three-dimensional Cole-Cole diagrams for linear and nonlinear electric susceptibilities. The results indicate that, in describing the nonlinear dielectric relaxation, the simplest spherical-top rotational diffusion model may be a sufficient approximation in some special cases only.
Źródło:
Acta Physica Polonica A; 2008, 114, 4; 687-698
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of SiC Surface Preparation on Homoepitaxial Growth; X-ray Reflectometric Studies
Autorzy:
Mazur, K.
Wierzchowski, W.
Wieteska, K.
Hofman, W.
Sakowska, H.
Kościewicz, K.
Strupiński, W.
Graeff, W.
Powiązania:
https://bibliotekanauki.pl/articles/1538812.pdf
Data publikacji:
2010-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.05.cm
61.72.Ff
61.72.up
Opis:
X-ray reflectometric and diffraction topographic methods were applied for examination of 4H and 6H silicon carbide substrates finished with various regimes, as well as, silicon carbide epitaxial layers. The investigations indicated a very good quality of the substrate surfaces finished with the process established at the Institute of Electronic Materials Technology, which provided the surface roughness σ = 0.55 ± 0.07 nm for 4H-SiC wafers. These values were better than those of substrate wafers offered by many commercial producers. The surface roughness was decreased during the initial high temperature etching to σ = 0.22 ± 0.07 nm. A relatively good structural quality was confirmed in the case of 4H epitaxial wafers deposited on the substrates prepared from the crystals manufactured at the IEMT, with the 8° off-cut from the main (001) plane.
Źródło:
Acta Physica Polonica A; 2010, 117, 2; 272-276
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On Temperature Dependence of Domain Structure in Cobalt
Autorzy:
Szmaja, W.
Polański, K.
Dolecki, K.
Powiązania:
https://bibliotekanauki.pl/articles/1964829.pdf
Data publikacji:
1997-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.60.-d
64.70.-p
Opis:
The type-I magnetic contrast in a scanning electron microscope is used to study the domain behaviour on the basal planes of cobalt monocrystals of different thicknesses during a heating cycle. Digital image processing is applied to the original scanning electron microscope images for their restoration, enhancement and analysis. The main reasons for the application of digital image processing are: low level of type-I magnetic contrast, particularly used at the higher temperatures, and the complex character of the magnetic domain structure. The changes in both domain structures and type-I magnetic contrast are due to the strong temperature dependence of magnetocrystalline anisotropy energy for the hcp phase of cobalt, which implies the rotation of magnetic easy axis from the c-axis to the basal plane. The temperature of the magnetic phase transition between an open-flux and a closed-flux domain configuration was found to be dependent on the specimen thickness. The changes in domain structure during the heating cycle were reversible under the condition that the specimen was not carried through the hcp-to-fcc phase transition. Otherwise, they were partially or completely irreversible and were caused by crystal imperfections originating from the transition. The paper shows the great advantage of using digital image processing system for data restoration, enhancement and analysis.
Źródło:
Acta Physica Polonica A; 1997, 92, 2; 469-472
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synchrotron White Beam Topographic Studies of Gallium Arsenide Crystals
Autorzy:
Wierzchowski, W.
Wieteska, K.
Graeff, W.
Powiązania:
https://bibliotekanauki.pl/articles/1964178.pdf
Data publikacji:
1997-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.10.-i
Opis:
A series of samples cut out from different types of gallium arsenide crystals with low dislocation density were studied by means of white beam synchrotron topography. The investigation was performed with transmission and back-reflection projection methods and transmission section method. Some of the topographs in transmission geometry provided a very high sensitivity suitable for revealing small precipitates. The transmission section images significantly differed depending on the wavelength and absorption. In some cases a distinct Pendellösung fringes and fine details of dislocation and precipitates images were observed. It was possible to reproduce the character of these images by means of numerical simulation based on integration of Takagi-Taupin equations. Due to more convenient choice of radiation, synchrotron back-reflection projection topography provided much better visibility of dislocations than analogous methods realized with conventional X-ray sources.
Źródło:
Acta Physica Polonica A; 1997, 91, 5; 1015-1019
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Problems of Mechanics of Metal Surface Layers
Autorzy:
Gambin, W.
Skalski, K.
Powiązania:
https://bibliotekanauki.pl/articles/1943988.pdf
Data publikacji:
1996-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.10.Cr
68.35.Gy
Opis:
Mechanics of metal surface layers deals with a description of the following objects, quantities and processes: structures and mechanical properties of metal surface layers after a heat, chemical, electro-chemical or physical treatment; evolution of these structures and properties during mechanical treatments; mechanical behaviour of the layers during exploitation processes. This branch of mechanics is based on the results of physical investigations, but it uses a mechanical approach. In the paper, descriptions of metal surface layers within the classical anisotropic plasticity, large strain plasticity, and finally, the crystal and polycrystal plasticity are recalled. Problems connected with a formulation of laws governing a surface layer behaviour are comprehensively discussed.
Źródło:
Acta Physica Polonica A; 1996, 89, 2; 145-154
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
X-Ray Topographic Investigation of Cellular Structure and its Relation to another Defects in Various Types of GaAs Single-Crystals
Autorzy:
Wierzchowski, W.
Mazur, K.
Powiązania:
https://bibliotekanauki.pl/articles/1929756.pdf
Data publikacji:
1993-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.10.-i
Opis:
The defect patterns in GaAs crystal grown using liquid encapsulated Czochralski and gradient freeze methods with various types of doping were characterized using complementary X-ray topographic methods. It was found that the cellular structure occurring in the low doped crystal is developed independently from the actual growth surface. The occurrence of the cellular structure is connected with significant lattice deformation, and some results point that significant stress can influence its formation. The high doping prevents formation of the cellular structure, but at higher doping the phenomenon of "cellular growth" can occur due to instabilities of the growth surface. The present results point that defect pattern in GaAs crystals is more affected by the type of doping than by the choice of the growth method.
Źródło:
Acta Physica Polonica A; 1993, 84, 4; 789-794
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Size effect in plasmon resonance of metallic nanoparticles: RPA versus COMSOL
Autorzy:
Kluczyk, K.
Jacak, W.
Powiązania:
https://bibliotekanauki.pl/articles/1075371.pdf
Data publikacji:
2016-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
36.40.Gk
73.20.Mf
Opis:
Size effect for plasmon resonance in metallic nanoparticles has been studied by finite element method solution of the Maxwell equations (COMSOL), by the Mie approach and microscopic random phase approximation model. Comparison with Au, Ag nanoparticles experimental data for light extinction in colloidal solutions with different particle sizes is presented for the three types of approach.
Źródło:
Acta Physica Polonica A; 2016, 129, 1a; A-83-A-86
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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