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Tytuł:
A Comparison of Different Estimation Methods for Hysteresis Modelling
Autorzy:
Jastrzębski, R.
Chwastek, K.
Biondić, I.
Miličević, K.
Powiązania:
https://bibliotekanauki.pl/articles/1030241.pdf
Data publikacji:
2017-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.60.-d
75.60.Ej
Opis:
The paper focuses on the estimation techniques for a low-dimensional phenomenological model of ferromagnetic hysteresis proposed by the Brazilian research group GRUCAD. The description is expressed with an ordinary differential equation and some auxiliary relationships. It describes both irreversible and reversible magnetization processes and addresses some problems inherent in the well-known Jiles-Atherton model. It is found that the differential evolution method is the most competitive technique for recovery of optimal model parameters.
Źródło:
Acta Physica Polonica A; 2017, 131, 5; 1228-1231
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Discrete and Continuous Analysis of Positron Lifetime Spectra: a Comparison
Autorzy:
Consolati, G.
Quasso, F.
Powiązania:
https://bibliotekanauki.pl/articles/2007998.pdf
Data publikacji:
1999-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
36.10.Dr
71.60.+z
78.70.Bj
Opis:
Positron lifetime spectra in poly[1-(trimethylsilyl)]propine membranes were collected at different temperatures and various number of accumulated counts, in order to compare the results from analyses obtained by different decay models: discrete (that is, purely exponential) or continuous (with at least one distribution of lifetimes). Analysis into four discrete components is inadequate, unless a low number of counts (1 to 2 millions) is accumulated. Conversely, deconvolutions which allow the ortho-positronium lifetime to be distributed give satisfactory fits, even at the highest statistics (60 millions). An equivalent good fit in terms of χ$\text{}^{2}$ test is obtained with a five discrete components analysis, from which it is possible to extract information on the first moments (centroid and standard deviation) of ortho -positronium lifetime distribution.
Źródło:
Acta Physica Polonica A; 1999, 95, 4; 505-508
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Comparison of Different Theoretical Models of Positron Lifetime Spectra for Polymers
Autorzy:
Kansy, J.
Powiązania:
https://bibliotekanauki.pl/articles/1812531.pdf
Data publikacji:
2008-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Bj
Opis:
The same reference positron lifetime spectra of polyurethane, measured in temperature range 112 to 390 K, were analyzed with three theoretical models: the "conventional" model with three exponential decay component of discrete values of lifetimes, a model with one discrete exponential component and two "packages" of exponentials with log-normal distribution of annihilation rates, and a model considering positronium slow localization, positronium internal relaxation as well as "delayed" formation of positronium. It turns out that the two latter models fit to the experimental data with the same excellent quality, in spite of the fact that in both models the ratio of intensities related to para-positronium and ortho-positronium was constrained to be as 1:3.
Źródło:
Acta Physica Polonica A; 2008, 113, 5; 1397-1407
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Comparison of Paraxial and Extended Paraxial Approach in Laser Propagation and Second Harmonic Generation
Autorzy:
Sharma, P.
Powiązania:
https://bibliotekanauki.pl/articles/1419745.pdf
Data publikacji:
2012-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
52.38.-r
52.38.Hb
52.38.Mf
Opis:
The propagation of laser beam in the plasma has been investigated for two cases, first with imposing the restriction of paraxial approximation on the beam profile, and second, relaxing the restriction on the profile up to a certain extent. The beam width parameter of the propagating laser beam has been compared for both the cases. Since the off-paraxial part of the beam affects background densities, consequently it will also influence the 2nd harmonic generation. Therefore, comparison of results has been done on the generated second harmonic, in the light of these two cases. A notable change is found in the magnitude of second harmonic yield in modified-paraxial case as compared to the paraxial case.
Źródło:
Acta Physica Polonica A; 2012, 122, 1; 122-127
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Comparison of the Valence Band Structure of Bulk and Epitaxial GeTe-based Diluted Magnetic Semiconductors
Autorzy:
Pietrzyk, M.
Kowalski, B.
Orlowski, B.
Knoff, W.
Story, T.
Dobrowolski, W.
Slynko, V.
Slynko, E.
Johnson, R.
Powiązania:
https://bibliotekanauki.pl/articles/1538868.pdf
Data publikacji:
2010-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.60.-i
71.20.Mq
71.20.Be
Opis:
In this work we present a comparison of the experimental results, which have been obtained by the resonant photoelectron spectroscopy for a set of selected diluted magnetic semiconductors based on GeTe, doped with manganese. The photoemission spectra are acquired for the photon energy range of 40-60 eV, corresponding to the Mn 3p → 3d resonances. The spectral features related to Mn 3d states are revealed in the emission from the valence band. The Mn 3d states contribution manifests itself in the whole valence band with a maximum at the binding energy of 3.8 eV.
Źródło:
Acta Physica Polonica A; 2010, 117, 2; 293-295
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Comparison for Grain Size Calculation of Cu-Zn Alloys with Genetic Programming and Neural Networks
Autorzy:
H. Karahan, İ.
Özdemir, R.
Powiązania:
https://bibliotekanauki.pl/articles/1402491.pdf
Data publikacji:
2015-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.05.Mh
81.15.Pq
Opis:
Neural Networks (NN) and Genetic Programming (GP) were used as a new method for formulation of grain size of electrodeposited $Cu_{1-x}Zn_x$ alloys as a function of Zinc and Copper content both electrolyte and the alloy films produced by electrodeposition technique. To predict grain size a great number of different expression models genetic programming and neural network were conducted. Each model differs from the other with their linking function, number of genes, head size, and chromosomes. To generate databases for the new grain size formulations, testing and training sets in total of 134 samples were selected at different Zn and Cu ratios of components. 6 different input parameters were selected and the output parameter was grain size of the electrodeposited Cu-Zn alloys. The testing and training sets consisted of randomly selected 106 and 28 for the proposed models. All results in the models indicated an applicable performance for predicting grain size of the alloys and found reliable. The predicted model showed that all of the input parameters effected on the resulting grain size. The NN and GEP based formulation results are compared with experimental results and found to be quite reliable with a very high correlation (R2 = 0.995 for GEP and 0.999 for NN).
Źródło:
Acta Physica Polonica A; 2015, 128, 2B; B-427-B-431
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cyclical Properties of the Credit and Production in Selected European Countries - a Comparison of Deterministic and Stochastic Cycle Approach
Autorzy:
Lenart, Ł.
Pipień, M.
Powiązania:
https://bibliotekanauki.pl/articles/1029291.pdf
Data publikacji:
2018-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
almost periodicity
spectral analysis
financial cycle
production cycle
Opis:
We develop two nonparametric approaches to analyze the empirical properties of economic cycles. The first approach is based on almost periodically correlated time series commonly used in signal processing. Within this framework we depart from standard scheme of analysis that relies on stationarity assumption. The second approach is based on spectral analysis provided the stationarity assumption of cyclical fluctuations. We contribute to the existing literature in both, theoretical and empirical aspects. From theoretical viewpoint we develop methods of formal statistical inference about the main properties of elements of the economic cycle. In the first approach the testing procedure utilizing subsampling approach is proposed. In the second approach the method of analysis of concentration of the spectral mass is developed. Based on the monthly series of the credit aggregate and the industrial production, taken from selected European countries, we discuss the empirical properties of the credit cycle and we compare them with the production cycle. Our empirical findings show substantial diversity of the credit cycle across analysed countries. Also cyclical component in the credit series is identified much stronger than in case of the series of industrial production. Also the production cycles are much more synchronized across countries compared to the credit cycles.
Źródło:
Acta Physica Polonica A; 2018, 133, 6; 1371-1387
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dielectric Study of Pure Polymer and Mixed Monomer-Polymer Single Crystals of pTS Diacetylene: a Comparison with Neutron Scattering Results
Autorzy:
Longevile, S.
Even, J.
Bertault, M.
Kołodziej, H. A.
Sworakowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1933586.pdf
Data publikacji:
1995-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.70.Kb
61.12.-q
77.84.Jd
Opis:
Temperature and frequency dependences of the electric permittivity in mixed monomer-polymer single crystals of the diacetylene pTS (2,4-hexadiynylene bis(p-toluenesulphonate)) are reported. The dependences were determined in the temperature range 100-250 K, and in the frequency range 100 Hz - 1 MHz. Two types of single crystals were studied: nearly-fully polymerized ones, and those containing ca. 20% of polymer in the monomer matrix. The dynamics is characterized by a high-frequency response (v ≫ 3 GHz) which corresponds to the soft mode analysed previously by the Raman and neutron inelastic scatterings. At low frequencies (v ≤ 1 kHz), another component is observed, its dielectric intensity peaking around the transition temperature in the fully polymerized crystals. The results are consistent with the results obtained from NMR and neutron scattering experiments.
Źródło:
Acta Physica Polonica A; 1995, 88, 2; 359-367
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reduction of Vibration of Fluid Loaded Plate with Piezoelectric Elements - a Comparison of Analytical, FEM Harmonic Analysis, and Real Results
Autorzy:
Iwański, D.
Wiciak, J.
Powiązania:
https://bibliotekanauki.pl/articles/1400083.pdf
Data publikacji:
2013-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.28.Js
43.30.-k
43.30.+m
Opis:
In the present paper, a comparison of analytical calculations, FEM harmonic analysis, and real data from laboratory stand of fluid-loaded structure were taken under consideration. Resonant frequencies of the investigated structure were measured using swept sine technique on laboratory stand. Analytical calculations of the first twelve modes were made and the numerical model was build using the finite element method. Results from real data, analytical calculations, and numerical calculations are comparable.
Źródło:
Acta Physica Polonica A; 2013, 123, 6; 1040-1043
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A comparison of the structural, electronic, optical and elastic properties of wurtzite, zinc-blende and rock salt TlN: A DFT study
Autorzy:
Farzan, M.
Elahi, S.
Salehi, H.
Abolhassani, M.
Powiązania:
https://bibliotekanauki.pl/articles/1159035.pdf
Data publikacji:
2016-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.15.Mb
71.20.-b
78.20.Ci
62.20.Dc
Opis:
In this article we investigated structural, electronic, elastic, and optical properties of TlN in three phases, using full potential linear augmented plane wave method in the density functional theory frame with WIEN2k code. The calculations have been done in the generalized Perdew-Burke-Ernzerhof generalized gradient approximation, the generalized Wu-Cohen gradient approximation, the generalized Perdew-Burke-Ernzerhof solid gradient approximation, local density approximation, and the modified Becke-Johnson approximations. In spite of the absence of any experimental data for TlN, our results are compared with other results achieved by other different approximations which shows a good agreement with them. The band gap for TlN in wurtzite and zinc-blende are obtained to be 0.07 and 0.09 eV within modified Becke-Johnson-local density approximation+spin-orbit approximation, respectively. The structural properties such as phase transitions, equilibrium lattice parameters, bulk modulus and its first pressure derivative were obtained using an optimization method. Moreover, we calculated quantities such as elastic constants, the Young modulus, shear modulus, the Poisson ratio, and sound velocities for longitudinal and transverse waves, the Debye temperature and the Kleinman parameters in different approximations and we show that TlN is softer than other nitrides of the III-group. The static calculations predicted that wurtzite to rock salt and zinc-blende to rock salt phase transitions occur at 14.7 GPa and 15.8, respectively. The optical properties of TlN in three phases, calculated in generalized gradient approximation and local density approximation and imaginary part of dielectric function show that TlN in wurtzite and zinc-blende phases have semiconductor properties but rock salt phase do not show. As well as, we investigate the influence of the hydrostatic pressure on the elastic parameters and energy band structures for TlN (zinc-blende) within local density approximation.
Źródło:
Acta Physica Polonica A; 2016, 130, 3; 758-768
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of Dynamic Dichroism Properties of Disperse Orange 11 Molecules and Azo-Molecules Doped in Poly(Methyl Methacrylate) Thin Films: A Comparison
Autorzy:
Abbas, B.
Alshikh Khalil, M.
Powiązania:
https://bibliotekanauki.pl/articles/1537688.pdf
Data publikacji:
2010-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
33.55.+b
78.20.e
78.66.Qn
Opis:
We investigate the dichroism characteristics of poly (methyl methacrylate) PMMA thin films doped with DO11, DO3, DSR13 and DSR1 dye molecules, which change under illumination with visible light. Our data show that photoisomerisation, phototautomerization reactions and light-induced polar orientation are dependent on the molecular structure of the polymer. Polar structure and molecular size, as well as the chemical structure of PMMA host, are the dominant parameters that determine both the extent and speed of dichroism buildup and relaxation processes. Two forms of DO11 molecules (keto and enol forms), and two other forms of azo-based dyes ( trans and cis forms) are responsible for the interaction with irradiating laser light and forming an anisotropic structure inside the PMMA/dye thin films.
Źródło:
Acta Physica Polonica A; 2010, 117, 6; 904-910
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Comparison of Different Approximate Two-Component Relativistic Theories of Many-Electron Systems: A Case Study of the Ionization Energies of Two-Electron Ions
Autorzy:
Barysz, M.
Flocke, N.
Karwowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/2027386.pdf
Data publikacji:
2001-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
31.15.-p
31.30.Jv
Opis:
The corrections to the ionization energies of two-electron ions due to relativistic effects are studied by different two-component relativistic methods. In particular, the results obtained by the standard Pauli-Cowan-Griffin method and by two variants of the Douglas-Kroll-Hess method (the one based on the free-particle transformation and the one in which the transformation accounts for the nuclear potential) are compared with those calculated using the four-component Dirac-Fock method. Limits of applicability of each of these methods have been indicated. Results acceptable in the whole range of the nuclear charge (relativistic corrections accurate up to 4% for Z≤85) are given only by the Douglas-Kroll-Hess method which goes beyond the free-particle transformation. Each of the other two approaches either underestimates or overestimates the corrections due to relativistic effects.
Źródło:
Acta Physica Polonica A; 2001, 99, 6; 631-641
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of Exchange-Correlations Effects (+U Corrections) on the Energy Levels of Mn and Fe Impurities in GaN and AlN: A Comparison with Experiment
Autorzy:
Zakrzewski, T.
Bogusławski, P.
Powiązania:
https://bibliotekanauki.pl/articles/1399156.pdf
Data publikacji:
2013-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
76.30.Fc
Opis:
Electronic structure of Mn and Fe impurities in GaN and AlN are calculated within the density functional theory in the generalized gradient approximation without and with the +U corrections. The comparison with the available experimental data shows that the results obtained with U = 0 are in good agreement with experiment. Inclusion of +U corrections makes the agreement worse.
Źródło:
Acta Physica Polonica A; 2013, 124, 5; 898-900
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of the Sensitivity of a Polymer Waveguide in the Classical and Reverse Symmetry System
Autorzy:
Gut, K.
Drewniak, S.
Powiązania:
https://bibliotekanauki.pl/articles/1506777.pdf
Data publikacji:
2010-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.25.Hz
42.25.-p
42.70.-a
42.82.-m
42.82.Et
68.35.Ct
Opis:
In this paper an analysis of two types of planar waveguides (with the conventional type of the layer and the reverse symmetry waveguide) is presented. In both types of the structure the polymer SU8 was used. In respect of its properties, this polymer is suitable as a waveguide layer. The analysis presented in this paper describes those structures working as sensors. We made a comparison of both types of configuration. We made a detailed analysis of the sensitivity of the covering layer when the thickness of the waveguide layer is changing and when the length of the wave activating the structure is changing, too.
Źródło:
Acta Physica Polonica A; 2010, 118, 6; 1133-1135
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of reduction methods for peak-to-average-power-ratio (PAPR) in MIMO-OFDM systems with a new approach
Autorzy:
Tören, M.
Çıflıklı, C.
Powiązania:
https://bibliotekanauki.pl/articles/1070391.pdf
Data publikacji:
2016-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
84.40.Ua
Opis:
This study is based on the comparison of the results of an analysis recommended for the peak-to-average-power-ratio (PAPR) reduction methods. This is one of the most significant problems in the multiple input-multiple output-orthogonal frequency division multiplexing (MIMO-OFDM) systems. The information in the signals of the wireless communication systems can be given in the frequency domain [S.H. Han, J.H. Lee, IEEE Signal Proc. Lett. 11, 887 (2004)]. Of the methods applied for the PAPR reduction, which is one of the problems occurring in the frequency domain of the signals in MIMO-OFDM systems, the selective mapping (SLM) and the partial transmit sequences (PTS) are compared using a different approach. In the MIMO-OFDM systems, Fourier analysis is performed and the values of the signals on the frequency plane are taken although it is not clear which value of the signal at which time is taken [S.H. Han, J.H. Lee, IEEE Signal Proc. Lett. 11, 887 (2004)]. For the constant state of time, Fourier analysis approach is not appropriate for the detection of accurate frequency values. To solve this problem, a new wavelet transform-based (WT) analysis is recommended for the MIMO-OFDM systems with a new approach. It is shown that this analysis will be preferred instead of the Fourier analysis because of the optimization of the frequency-based temporary solutions of the signal. This approach of analysis is used along with the methods used for solving the PAPR problem in the MIMO-OFDM systems. Thereby, a comparison showing at which rate the methods for the solution of the problem contribute to solving the problem with this approach can be carried out. Numerical results show at which rate the methods with this approach can be carried out to contribute for solving the problem.
Źródło:
Acta Physica Polonica A; 2016, 130, 1; 417-421
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
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