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Tytuł:
Wreath Product in Factorization of Holosymmetric Group
Autorzy:
Florek, W.
Lulek, T.
Powiązania:
https://bibliotekanauki.pl/articles/1887747.pdf
Data publikacji:
1991-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.50.Em
02.20.+b
Opis:
The holosymmetric group Q of an n-dimensional crystal lattice determined by a given lattice basis B is considered. This group is contained in the n-dimensional orthogonal group O(n) so its elements preserve the orthogonality of basis vectors and their lengths. These conditions yield the decomposition of lattice basis into orthogonal sublattices and next the factorization of the holosymmetric group, which can be written as a direct product of complete monomial groups of k-dimensional (k ≤ n) holosymmetric groups. Simple, decomposable and primitive holosymmetric groups are discussed. The results for n ≤ 4 are presented.
Źródło:
Acta Physica Polonica A; 1991, 79, 6; 843-852
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New Method for Studying Biaxial Deformation Effects on Optical Spectra of Quantum Wells
Autorzy:
Sosin, T. P.
Trzeciakowski, W.
Powiązania:
https://bibliotekanauki.pl/articles/1931925.pdf
Data publikacji:
1995-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.66.Fd
73.20.Dx
Opis:
The effects of large deformation were studied by preparing thin (20-30 μm) membranes with quantum-well layers on top. A small gas pressure of a few bar deforms the membrane substantially and changes the optical spectra of the quantum wells. We present the results of the photoluminescence and absorption from GaAs/AlGaAs and from InGaAs/GaAs quantum wells subjected to tensile and to compressive biaxial strain. The light-hole lines shift more than two times faster than the heavy-hole lines so that they cross under tensile strain.
Źródło:
Acta Physica Polonica A; 1995, 87, 1; 151-156
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
NDT of Rating Impact of Laser Padding on the Surface Layer
Autorzy:
Napadłek, W.
Witoś, M.
Prusik, T.
Powiązania:
https://bibliotekanauki.pl/articles/1030457.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Bx
81.15.Fg
03.75.Pp
81.70.Ex
81.70.Fy
75.50.Bb
06.20.-f
06.60.Mr
Opis:
The article presents the problem of quality control the paramagnetic material of weld overlays laser made on ferro- and paramagnetic materials (steels, cast iron). To assess the quality of weld overlays paramagnetic material, and also the impact of overheating, besides laboratory researches on Keyence optical microscope, used measurement of existing magnetization of magnetic field distribution. Examples of test results by magnetic memory of metals are presented. It has been found, that is expedient use magnetic methods to assess the quality the microstructure of laser pad welded surface layer (influence of heat generation, microstructure changes, chemical composition and own stresses).
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 707-709
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of technological parameters of the casting process on the structure and selected properties of iron-based metallic glasses
Autorzy:
Pilarczyk, W.
Jung, T.
Babilas, R.
Powiązania:
https://bibliotekanauki.pl/articles/1112027.pdf
Data publikacji:
2016-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.05.cp
81.05.Bx
81.05.Kf
81.70.Bt
81.70.Pg
Opis:
The main aim of this paper was to produce amorphous ribbons with specified composition with the use of various process parameters and X-ray qualitative and quantitative phase analysis after casting and heat treating. Station for ultra-fast cooling of the molten alloy with high vacuum pumps designed for the production of metallic glasses in the form: of ribbons with the use of Bühler Melt Spinner SC was used. The X-ray qualitative and quantitative phase analysis, microscopic observation, microhardness and thermal properties tests of the investigated ribbons were conducted. Based on experimental data the discussion on the correlation between casting process parameters, phase and quantitative composition and heat treatment was carried out.
Źródło:
Acta Physica Polonica A; 2016, 130, 4; 923-926
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Results of Modeling Semiconductor Sensor Layers in SAW Gas Sensors
Autorzy:
Hejczyk, T.
Urbańczyk, M.
Jakubik, W.
Powiązania:
https://bibliotekanauki.pl/articles/1506793.pdf
Data publikacji:
2010-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
77.65.Dq
68.35.Iv
07.07.Df
Opis:
The paper presents the numerical results of investigations of the layered gas surface acoustic waves sensor. The base electric load of the piezoelectric acoustic line is predicted by the effect of surface acoustic waves velocity changes vs. surface conductivity, which depends on the profile concentration by gas diffused molecules into the porous film. Inside the sensor layer Knudsen's model of gas diffusion was used.
Źródło:
Acta Physica Polonica A; 2010, 118, 6; 1158-1160
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Physics of Resonant Tunnelling
Autorzy:
Sheard, F. W.
Fromhold, T. M.
Powiązania:
https://bibliotekanauki.pl/articles/1920955.pdf
Data publikacji:
1992-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.20.Dx
Opis:
A description is given of resonant tunnelling processes in double-barrier semiconductor heterostructures from the point of view of sequential theory. If a magnetic field is applied in the plane of the barrier interfaces, the energy and transverse momentum of the electrons injected into the quantum well through the emitter tunnel barrier can be varied independently by changing the applied voltage and magnetic field. This technique can be used to probe the energy and momentum spectrum of the subband states in a quantum well. In n-type wide-well structures, a detailed interpretation of magneto-oscillations in the tunnel current has been given in terms of semiclassical orbits of electrons in the well. In p-type structures with narrow wells, the dispersion curves of hole subbands, which are complicated by the strong mixing of light hole and heavy hole states, have been directly studied. Resonant tunnelling into the bound state of single donor atoms in a quantum well has recently been observed. The magnetic field dependence of the tunnel current then gives a measure of the transverse momentum distribution and hence lateral extent of the donor wave function.
Źródło:
Acta Physica Polonica A; 1992, 82, 4; 523-538
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
DX Puzzle: Where Are We Now?
Autorzy:
Wilamowski, Z.
Suski, T.
Jantsch, W.
Powiązania:
https://bibliotekanauki.pl/articles/1920958.pdf
Data publikacji:
1992-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.Jv
71.55.-i
Opis:
A brief review of the experimental data on the metastable DX-centers in AlGaAs is presented. The experimental proofs of the two-electron nature and of the intermediate, one-electron state of the DX-centers are discussed. We collect the available experimental data on the ground state, electron-emission and capture energies and we discuss the nature of the lattice barrier. The effect of splitting of these energies in AlGaAs alloys and the consequences of the splitting on the capture and emission kinetics are analyzed. The different character of the barrier and of the alloy splitting for donors of the IV and VI group is underlined. The necessity to consider the interdonor Coulomb interaction when discussing the experimental data is also pointed out.
Źródło:
Acta Physica Polonica A; 1992, 82, 4; 561-571
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Diluted Magnetic Semimetals - Beyond Heisenberg Coupling
Autorzy:
Wilamowski, Z.
Story, T.
Jantsch, W.
Powiązania:
https://bibliotekanauki.pl/articles/1931949.pdf
Data publikacji:
1995-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.20.-g
75.30.Hx
76.20.+q
Opis:
We analyse effects which cannot be explained assuming the isotropic Heisenberg form of sp-d or of the indirect d-sp-d (RKKY) coupling. Resonance line broadening, a line shift and an enhancement of the magnetic anisotropy in diluted magnetic semimetals are discussed.
Źródło:
Acta Physica Polonica A; 1995, 87, 1; 189-192
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of Core-Hole Screening on Spin-Polarised Auger Spectra from Ferromagnetic Ni
Autorzy:
Wegner, T.
Potthoff, M.
Nolting, W.
Powiązania:
https://bibliotekanauki.pl/articles/2013223.pdf
Data publikacji:
2000-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.20.Fv
71.20.Be
75.60.Ej
Opis:
We calculate the spin- and temperature-dependent local density of states for ferromagnetic Ni in the presence of a core hole at a distinguished site in the lattice. Correlations among the valence electrons and between valence and core electrons are described within a multi-band Hubbard model which is treated by means of second-order perturbation theory around the Hartree-Fock solution. The core-hole potential causes strong screening effects in the Ni valence band. The local magnetic moment is found to be decreased by a factor of 5-6. The consequences for the spin polarisation of CVV Auger electrons are discussed.
Źródło:
Acta Physica Polonica A; 2000, 97, 3; 567-570
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High Pressure - High Temperature Diffraction Study of MnTe Using Synchrotron Radiation
Autorzy:
Paszkowicz, W.
Dynowska, E.
Peun, T.
Powiązania:
https://bibliotekanauki.pl/articles/1964125.pdf
Data publikacji:
1997-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.30.+t
62.50.+p
65.70.+y
Opis:
High pressure - high temperature experiments for MnTe of NiAs type were performed using a synchrotron radiation as X-ray source and a cubic anvil X-ray diffraction press to produce nonambient sample environment. In the investigated range of pressure (0-67.5 kbar) on uploading and with following temperature rise from 296 to 1273 K (at 67.5 kbar), the structure type of MnTe is conserved. An earlier reported nonlinear behaviour of lattice-parameter c$\text{}_{0}$ is not found in the present study. Possible reasons of this discrepancy are discussed. The value of bulk modulus and its pressure derivative were calculated from the pressure-volume dependence by fitting the Birch-Murnaghan equation.
Źródło:
Acta Physica Polonica A; 1997, 91, 5; 939-944
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Resonant Tunnelling in Double-Barrier Heterostructures with an Accumulation Layer
Autorzy:
Wosiński, T.
Figielski, T.
Mąkosa, A.
Wrotek, S.
Dobrowolski, W.
Powiązania:
https://bibliotekanauki.pl/articles/1992612.pdf
Data publikacji:
1998-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.40.Gk
73.50.Jt
85.30.Mn
Opis:
Two modes of electron gas injection in resonant tunnelling through GaAs/AlGaAs double-barrier heterostructures were revealed while studying their current-voltage characteristics. Examining peculiarities of the characteristics within the temperature range 4-350 K and under a high magnetic field, we were able to distinguish the contribution to resonant tunnelling of ballistic electrons injected from a three-dimensional electron gas in the emitter contact and that of electrons injected from a two-dimensional electron gas in the accumulation layer formed near the emitter barrier.
Źródło:
Acta Physica Polonica A; 1998, 94, 3; 617-621
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Density of Gap States Deconvoluted from Photoconductive Spectra for Undoped Amorphous Silicon and Silicon-Carbon Thin Films
Autorzy:
Pisarkiewicz, T.
Stapiński, T.
Adriaenssens, G.
Lauwerens, W.
Rava, P.
Powiązania:
https://bibliotekanauki.pl/articles/1873043.pdf
Data publikacji:
1995-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.20.Dx
Opis:
Density of states in amorphous hydrogenated silicon and silicon-carbon thin films were calculated by deconvolution of the optical absorption coefficient a! measured by constant photocurrent method. Addition of carbon to silicon lattice increases the optical band-gap and influences the distribution of defect states in the gap.
Źródło:
Acta Physica Polonica A; 1995, 87, 2; 407-410
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Polarization Mode Dispersion in Birefringent Optical Fibers
Autorzy:
Woliński, T. R.
Domański, A. W.
Powiązania:
https://bibliotekanauki.pl/articles/2035695.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.81.Gs
42.81.Pa
42.25.Ja
42.25.Dd
Opis:
The paper discusses influence of polarization mode dispersion on performance of polarimetric systems with highly birefringent fibers. It appeared that polarization mode dispersion strongly influences a degree of polarization that depends on coherence of the light source used and simultaneously diminishes dynamics of the output signal.
Źródło:
Acta Physica Polonica A; 2003, 103, 2-3; 211-219
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electric Field Enhanced Emission of Holes from the Double Donor Level of the EL2 Defect in GaAs
Autorzy:
Mąkosa, A.
Wosiński, T.
Szkiełko, W.
Powiązania:
https://bibliotekanauki.pl/articles/1923805.pdf
Data publikacji:
1992-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.Eq
61.70.-r
Opis:
Strong electric-field enhancement of the thermal emission rate of holes from the doubly ionized charge state of the EL2 defect was revealed with the deep-level transient spectroscopy in p-type GaAs and analyzed in a model of phonon-assisted tunnel effect. Similar dependence observed for the electric field directions parallel to three main crystallographic axes suggests tetrahedral symmetry of the defect which is consistent with its identification as the arsenic antisite.
Źródło:
Acta Physica Polonica A; 1992, 82, 5; 813-816
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Simulation of Bragg-Case Section Images οf Dislocations and Inclusions in Aspect of Identification of Defects in SiC Crystals
Autorzy:
Balcer, T.
Wierzchowski, W.
Wieteska, K.
Powiązania:
https://bibliotekanauki.pl/articles/1538998.pdf
Data publikacji:
2010-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.Ff
61.72.up
Opis:
The numerical simulation has been applied for studying of Bragg-case section topographic images of dislocation and rod-like inclusions. The validity of simple approximation of extinction contrast was confirmed in the case of screw dislocations in silicon carbide crystals. A procedure for approximate calculation of the strain field of rod-like inclusion was constructed, consisting of adding the contributions from a very large number of point-like inclusions uniformly distributed inside the assumed volume of the inclusion. The procedure ensured a reasonable similarity between the simulated topographs and experimental Bragg-case section topographic images of some pipe-formed cavities in silicon carbide crystals. The method is useful for some other materials, e.g. it enabled to compute realistic simulation of plane-wave topographs of the rod-like inclusions in YAG.
Źródło:
Acta Physica Polonica A; 2010, 117, 2; 336-340
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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