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Wyszukujesz frazę "05.70.-a" wg kryterium: Temat


Wyświetlanie 1-35 z 35
Tytuł:
Endoreversible Modeling and Optimization of a Multistage Heat Engine System with a Generalized Heat Transfer Law via Hamilton-Jacobi-Bellman Equations and Dynamic Programming
Autorzy:
Xia, S.
Chen, L.
Sun, F.
Powiązania:
https://bibliotekanauki.pl/articles/1504513.pdf
Data publikacji:
2011-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.70.-a
05.60.Cd
05.70.Ln
Opis:
A multistage endoreversible Carnot heat engine system operating between a finite thermal capacity high-temperature fluid reservoir and an infinite thermal capacity low-temperature environment with a generalized heat transfer law [q ∝ ( Δ $(T^{n}))^{m}$] is investigated in this paper. Optimal control theory is applied to derive the continuous Hamilton-Jacobi-Bellman equations, which determine the optimal fluid temperature configurations for maximum power output under the conditions of fixed initial time and fixed initial temperature of the driving fluid. Based on the general optimization results, the analytical solution for the case with Newtonian heat transfer law [q ∝ Δ(T)] is further obtained. Since there are no analytical solutions for the other heat transfer laws, the continuous Hamilton-Jacobi-Bellman equations are discretized and the dynamic programming algorithm is adopted to obtain the complete numerical solutions of the optimization problem, and the relationships among the maximum power output of the system, the process period and the fluid temperature are discussed in detail. The results show that the optimal high-temperature fluid reservoir temperature for the maximum power output of the multistage heat engine system with Newtonian and linear phenomenological [q ∝ Δ $(T^{-1})$] heat transfer laws decrease exponentially and linearly with time, respectively, while those with the Dulong-Petit [q∝$(Δ T)^{1.25}$], radiative [q∝ Δ $(T^4)$] and [q∝$(Δ(T^4))^{1.25}$] heat transfer laws are different from the former two cases significantly.
Źródło:
Acta Physica Polonica A; 2011, 119, 6; 747-760
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performance Prediction and Irreversibility Analysis of a Thermoelectric Refrigerator with Finned Heat Exchanger
Autorzy:
Meng, F.
Chen, L.
Sun, F.
Powiązania:
https://bibliotekanauki.pl/articles/1493399.pdf
Data publikacji:
2011-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.70.-a
05.60.Cd
05.70.Ln
Opis:
A developed model of commercial thermoelectric refrigerators with finned heat exchanger is established by introducing finite time thermodynamics. A significant novelty is that physical properties, dimension parameters, temperature parameters and flow parameters are all taken into account in the model. Numerical studies and comparative investigation on the performance of a typical commercial water-cooling thermoelectric refrigerator which consists of 127 thermoelectric elements, are performed for cooling load and coefficient of performance. The results show that the maximum cooling load is 2.33 W and the maximum coefficient of performance is 0.54 when the cooling temperature difference is 10 K. Comparing the simulation results of several models, it is found that the heat convection of the heat exchanger and the heat leakage through the air gap are the main factors, which cause irreversibility and decrease the performance. Moreover, the performance can be improved by optimizing the length and cross-section area of thermoelectric elements. The model and calculation method may be applied to not only the analysis and performance prediction of practical thermoelectric refrigerators, but also the design and optimization of heat exchangers.
Źródło:
Acta Physica Polonica A; 2011, 120, 3; 397-406
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermodynamic Interpretation of Pressure-Induced Spin Transitions in Thiosemicarbazonates of Iron(III)
Autorzy:
Krupska, A.
Powiązania:
https://bibliotekanauki.pl/articles/1399168.pdf
Data publikacji:
2013-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.70.-a
82.60.-s
Opis:
The thermodynamic interpretation of the spin transition in iron(II) complexes taking into consideration cooperative domains is given in the literature. We use a similar interpretation for thiosemicarbazonates of aromatic aldehydes of iron(III) compounds. We extend the spin transition interpretation to pressure-induced spin transitions. The relationship between a domain size n and the interaction between a high spin and a low spin states Γp given by Gütlich et al. allows us to deduce a modified equation of the spin transition pressure $p_{c}$ (at the temperature $T=T_{c}$). On the basis of this equation, the content of the fraction of the high spin state γ and of the fraction of the low-spin state, 1-γ, as a function of pressure can be theoretically estimated. The derived equation enables us to predict the width of hysteresis which refers to the high spin and low spin states formed under the high pressure as a result of the spin transition.
Źródło:
Acta Physica Polonica A; 2013, 124, 4; 626-628
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
In Quest of the Best Theoretical Description of Excess Molar Functions οf Binary Mixtures of Alcohols
Autorzy:
Geppert-Rybczyńska, M.
Hofman, T.
Powiązania:
https://bibliotekanauki.pl/articles/1811517.pdf
Data publikacji:
2008-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.70.-a
05.70.Ce
82.60.Lf
Opis:
An attempt to describe excess molar functions of alkane + alcohol and alcohol + alcohol binary mixtures was made using the theoretical approach constructed on the basis of S-ERAS model and the chemical theory proposed by Campbell. The results obtained seem to be promising, however in order to complete the work, the procedure of determination of fitting parameters as well as relative magnitude of physical and chemical contributions to regarded excess molar quantities must be established.
Źródło:
Acta Physica Polonica A; 2008, 114, 6A; A-91-A-96
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on thermodynamic properties of Fe³⁺-substituted yttrium iron garnets
Autorzy:
Modi, K.
Jha, P.
Raval, P.
Vasoya, N.
Vyas, K.
Meshiya, U.
Gohil, R.
Jadav, K.
Gohil, N.
Sharma, P.
Powiązania:
https://bibliotekanauki.pl/articles/1158494.pdf
Data publikacji:
2016-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.47.Lx
05.70.-a
Opis:
This paper presents the molar heat capacity at constant volume C_{V} and characteristic Debye temperature θ, determination for the garnet system, Y_{3-x}Fe_{5+x}O_{12}, x=0.0, 0.1, 0.3, and 0.5 at 300 K. The θ values determined from Waldron's approach and those calculated using ultrasonic mean sound velocity, V_{mo}, are in agreement. C_{V} values calculated from the Einstein theory are consistent with the reported one and theoretically expected values using the Dulong-Petit law, but Waldron's approach based on the Debye theory and the Debye T³ law fail to estimate consistent C_{V} values. The result has been discussed in the light of key physical differences between the two theories. The applicability of the Kieffer model for molar heat capacity at constant pressure, C_{p}, determination has been tested. Finally, an attempt has been made to estimate electronic contribution and the temperature at which the lattice contribution and electronic contribution to the molar heat capacity become comparable.
Źródło:
Acta Physica Polonica A; 2016, 130, 3; 778-784
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermodynamics of the Exactly Solvable Spin-Electron Tetrahedral Chain
Autorzy:
Gálisová, L.
Powiązania:
https://bibliotekanauki.pl/articles/1402558.pdf
Data publikacji:
2015-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.70.-a
75.10.Pq
Opis:
An exactly solvable spin-electron tetrahedral chain, where the Ising spins localized at nodal lattice sites regularly alternate with three equivalent lattice sites available for one mobile electron is considered. The system with ferromagnetic interaction between the Ising spins and electrons exhibits an enhanced magnetocaloric effect in the limit H/|J| → 0 when the entropy is very small, whereas the system with antiferromagnetic interaction between the Ising spins and electrons exhibits an enhanced magnetocaloric effect around the field H/J=1 when the entropy is sufficiently close to the value S/2N = ln[(1+√5)/2]. We study the thermodynamics of the system in these field regions.
Źródło:
Acta Physica Polonica A; 2015, 128, 2; 156-158
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of Irreversible Processes across Narrow Junctions
Autorzy:
Honig, J.
Hoehn, R.
Powiązania:
https://bibliotekanauki.pl/articles/1505330.pdf
Data publikacji:
2011-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.70.-a
05.70.Ln
44.10.+i
Opis:
The rectification of the second law of thermodynamics is used to directly relate irreversible heat and work transfers to reversible processes. This permits the construction of thermodynamic functions of state that include entropy contributions due to irreversible processes. A general expression is set up to determine the entropy changes in terms of experimentally accessible parameters when a system is interacting with its surroundings via quasistatic irreversible operations. The procedure is used to determine the entropy changes across a narrow junction in terms of pressure and temperature differences between the system and its surroundings, including cyclic processes.
Źródło:
Acta Physica Polonica A; 2011, 119, 3; 323-327
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Asymmetry Driven Phase Transformations
Autorzy:
Damczyk, J.
Ostasiewicz, K.
Radosiński, Ł.
Radosz, A.
Powiązania:
https://bibliotekanauki.pl/articles/1535592.pdf
Data publikacji:
2010-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.70.-a
64.60.-i
63.70.+h
Opis:
Motivated by the properties of one-dimensional lattice systems with asymmetric on-site potential, one can formulate a hypothesis of an asymmetry driven phase transformation. Characteristic feature of one-dimensional systems exhibiting asymmetry driven phase transformation is a sequence of the two phase conversions. In particular class of such systems with a triple-well potential, phase conversions of one-dimensional systems would evolve into a sequence of two phase transitions in three-dimensional models. We propose here a model of three-dimensional system exhibiting a sequence of two first order asymmetry driven phase transitions.
Źródło:
Acta Physica Polonica A; 2010, 118, 4; 527-530
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical Study of the Frustrated Ising Antiferromagnet on the Honeycomb Lattice
Autorzy:
Bobák, A.
Lučivjanský, T.
Žukovič, M.
Borovský, M.
Balcerzak, T.
Powiązania:
https://bibliotekanauki.pl/articles/1032632.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
05.70.-a
75.10.Hk
Opis:
We study effects of the next-next-nearest-neighbour antiferromagnetic (J₃ < 0) interaction on critical properties (or phase diagram) of the frustrated spin-½ J₁-J₂-J₃ Ising antiferromagnet on the honeycomb lattice by using the effective-field theory with correlations. Beside the ground-state energy, we find that there is a region of J₃ < 0 in which the frustrated honeycomb lattice antiferromagnet exhibits a tricritical point, at which the phase transition changes from the second order to the first one on the line between Néel antiferromagnetic and paramagnetic phases.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 636-638
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of the Molecular Shape on Its Thermodynamic Functions
Autorzy:
Lewandowska, A.
Konarski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1813167.pdf
Data publikacji:
2008-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.20.-y
05.70.-a
33.10.Cs
Opis:
Free energy and entropy were calculated for molecules of different shapes in gas phase and under small pressure. The values of the thermodynamic functions were found strongly dependent on the molecular shape. The results obtained were applied to predict the route of internal energy deactivation as well as the preferred form of the molecules examined.
Źródło:
Acta Physica Polonica A; 2008, 113, 4; 1111-1115
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Semi-Empirical Modelling of Glass Forming Ranges for Y-Co-Si System
Autorzy:
Śniadecki, Z.
Narojczyk, J.
Idzikowski, B.
Powiązania:
https://bibliotekanauki.pl/articles/1366620.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.70.-a
61.43.Dq
81.30.Bx
Opis:
Glass forming abilities of a ternary Y-Co-Si system were determined on the basis of combined semi-empirical Miedema's and geometric models. The enthalpy of amorphous and solid solution phases formation, along with the mismatch entropy and GFA parameter, were analysed to indicate compositions with the highest ability for the amorphization. The large atomic radii difference between constituents, especially Y and Si, is the deciding factor of GFA. Compositions ranged between $Y_{33}Si_{67}$ and $Y_{45}Si_{55}$ are the best glass formers.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 62-63
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tsallis Entropies of Superposition States οf Two Photon-Subtracted SU(1,1) Coherent States and Entanglement Transfer to Qubits
Autorzy:
Liang, Mai-Lin
Yuan, Bing
Zhang, Jia-Nan
Powiązania:
https://bibliotekanauki.pl/articles/1584983.pdf
Data publikacji:
2009-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.50.Dv
03.65.Ud
05.70.-a
Opis:
Entropy properties of the superposed photon-subtracted two-mode coherent states are quite different from that of the single state. Tsallis entropies of the superposed states have extreme values, while that of the single state change monotonously. Further, it is found that the positions of the maxima of the entropies are independent of the entropic index. Around the maxima of the entropies, the entanglement transfer from the superposed states to two initially separable qubits is nearly complete.
Źródło:
Acta Physica Polonica A; 2009, 116, 6; 1006-1010
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of a Mixed Hadronic-QGP System with Massive Particles
Autorzy:
Ghenam, L.
El Djoudi, A.
Powiązania:
https://bibliotekanauki.pl/articles/1402384.pdf
Data publikacji:
2015-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
12.38.Mh
12.39.Ba
05.70.-a
05.70.Ce
05.70.Fh
64.10.+h
Opis:
We consider a mixed system of hadronic and quark-gluon plasma (QGP) phases in a finite volume, and use a phenomenological approach with two phases matter equations of state to study the occurring deconfinement phase transition with varying temperature and/or chemical potential. We take into account massive particles in both phases, and calculate several physical quantities describing well the system at the phase transition. We probe the behaviour of these quantities, by examining their variations with temperature and volume at fixed chemical potential, as well as with chemical potential and volume at fixed temperature, in three dimensional plots, and obtain the finite size effects on the deconfinement phase transition.
Źródło:
Acta Physica Polonica A; 2015, 128, 2B; B-341-B-343
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some Elastic Properties and Phase Transitions in Some Alkali Halides Using Interatomic Potential Model
Autorzy:
Yazar, H. R.
Powiązania:
https://bibliotekanauki.pl/articles/2046838.pdf
Data publikacji:
2006-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Fv
05.70.-a
61.50.Ks
64.10.+h
Opis:
We have predicted the phase transition pressure in some alkali halides using an interatomic potential approach based on rigid ion model. This potential form represents the composite form of the inverse power dependence and exponential dependence of the repulsive energy on interionic distance. Some thermoelastic properties such as second order elastic constants have been calculated using the same potential. The phase transition pressures (28.69 and 2.4 GPa) obtained by us for two alkali halides (NaCl and KCl) are in closer agreement with their corresponding experimental data (29.0 and 2.0 GPa). This approach is promising with respect to prediction of the phase transition pressure of other alkali halides as well.
Źródło:
Acta Physica Polonica A; 2006, 109, 6; 743-751
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optoacoustic Measurements for Small-Volume Liquid Samples
Autorzy:
Egerev, S.
Powiązania:
https://bibliotekanauki.pl/articles/1377936.pdf
Data publikacji:
2015-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.35.Bf
43.35.Sx
05.70.-a
42.40.My
42.55.-f
Opis:
High sensitivity of optoacoustic measurement method makes it possible to use it for the analysis of the liquid samples having microliter volume. The core of any measurement optoacoustic system is represented by a so-called optoacoustic cell. The paper deals with a layered prism optoacoustic cell. It is well-suited for the small-volume sample analysis. In the paper, laser-induced elastic pulse in the layered prism cell is examined at the stage of its generation, at the stage of its propagation through the body of the cell, and at the stage of the wideband pick-up with the piezoelectric transducer. This pulse serves to determine trace concentrations of various impurities in the sample. The optimization of layered prism cell parameters is proposed. Figures of merit of optoacoustic determination of lipopolysaccharides in the liquid small-volume sample with the use of the optimized layered prism cell are evaluated as an example.
Źródło:
Acta Physica Polonica A; 2015, 127, 1; 10-14
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Models of Pedestrian Evacuation based on Cellular Automata
Autorzy:
Mrowinski, M.
Gradowski, T.
Kosinski, R.
Powiązania:
https://bibliotekanauki.pl/articles/1409052.pdf
Data publikacji:
2012-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
89.40.-a
45.70.Vn
05.50.+q
05.70.Fh
Opis:
We study two models of pedestrian evacuation based on cellular automata and intelligent agents. We use the static floor field approach and augment it with additional transition rules (random movement and preservation of personal space) in order to model various aspects of human behaviour. Through numerical simulations we investigate pedestrian evacuation from rooms with various geometries (e.g. empty room, classroom). Using heatmaps (density diagrams of pedestrians), average evacuation times, velocity and other parameters we study the effectiveness of evacuation and potential dangers pedestrians may encounter.
Źródło:
Acta Physica Polonica A; 2012, 121, 2B; B-95-B-100
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
External Noise Effects on the Electron Velocity Fluctuations in Semiconductors
Autorzy:
Persano Adorno, D.
Pizzolato, N.
Spagnolo, B.
Powiązania:
https://bibliotekanauki.pl/articles/1813387.pdf
Data publikacji:
2008-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.70.+m
05.40.Ca
05.40.-a
Opis:
We investigate the modification of the intrinsic carrier noise spectral density induced in low-doped semiconductor materials by an external correlated noise source added to the driving high-frequency periodic electric field. A Monte Carlo approach is adopted to numerically solve the transport equation by considering all the possible scattering phenomena of the hot electrons in the medium. We show that the noise spectra are strongly affected by the intensity and the correlation time of the external random electric field. Moreover, this random field can cause a suppression of the total noise power.
Źródło:
Acta Physica Polonica A; 2008, 113, 3; 985-988
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rise and Fall of Reentrant Phase Transitions in a Coupled Spin-Electron Model on a Doubly Decorated Honeycomb Lattice
Autorzy:
Čenčariková, H.
Strečka, J.
Powiązania:
https://bibliotekanauki.pl/articles/1032648.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
05.70.Fh
71.27.+a
75.30.Kz
Opis:
Phase diagrams and spontaneous magnetization are rigorously calculated for a coupled spin-electron model on a doubly decorated honeycomb lattice, which accounts for a quantum-mechanical hopping of the mobile electrons on decorating sites, the nearest-neighbor Ising coupling between mobile electrons and localized spins, as well as the further-neighbor Ising coupling between the localized spins placed on nodal sites. The spontaneously ordered ferromagnetic phase, spontaneously ordered antiferromagnetic phase and disordered paramagnetic phase emerge in a phase diagram depending on an electron filling of the decorating sites, a relative size of the hopping term and both considered coupling constants. It is evidenced that a nature and size of the further-neighbor Ising coupling between the localized spins basically influences rise and fall of reentrant transitions close to a phase boundary between the paramagnetic phase and both spontaneously ordered phases.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 1021-1023
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New type of composite gyrotropic metamaterial
Autorzy:
Paśko, W.
Zięba, P.
Tralle, I.
Çoruh, A.
Powiązania:
https://bibliotekanauki.pl/articles/1055044.pdf
Data publikacji:
2017-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Xj
81.05.Zx
78.67.Pt
42.70.-a
Opis:
In this work we examined the possibility of fabricating the metamaterial in a relatively simple way. Our idea was to use the three-component mixture of ingredients, where one of them is responsible for the negative permeability μ(ω) of hypothetical metamaterial, while the other two cause the negative value of effective permittivity ε(ω). In our previous work, we considered Hg_{1-x}Cd_xTe semiconductor compound as one of the ingredients of mixture. As fabrication of the Hg_{1-x}Cd_xTe is related to using mercury which is very poisoning, we tried to exclude this material. In the work we proved by numerical simulations the possibility of substituting mercury cadmium telluride by Pb_{1-x}Sn_xTe. We have shown by computer simulations that by the proper fitting of the parameters, e.g. the radius of nanoparticles, their magnetic moments, the relative concentration of ingredients, etc., it is possible to obtain the metamaterial with negative refraction index in a relatively broad range of temperatures and magnetic fields. The last seems to be very promising in terms of practical applications of metamaterials.
Źródło:
Acta Physica Polonica A; 2017, 132, 1; 121-123
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Asymmetry Coefficients as Indicators of Chaos
Autorzy:
Wąż, P.
Bielińska-Wąż, D.
Powiązania:
https://bibliotekanauki.pl/articles/1584980.pdf
Data publikacji:
2009-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.70.Rr
95.10.Fh
05.45.-a
05.45.Gg
05.45.Tp
Opis:
The aim of this paper is to present a new simple indicator of chaos derived from the dynamics of the motion. For this purpose statistical methods are used. A function describing the motion of the analyzed system (in the example under consideration, the time dependence of the angle of a damped driven pendulum, ω(t)) is recorded in time intervals t∊〈 $T_{s}$, $T_{f_{k}}$〉, k = 1, 2,...K, with $T_{f_{k}}$ > $T_{f_{k-1}}$. Each of the recorded functions is considered as a statistical distribution. The asymmetry coefficients of the set of distributions form a series and their behavior in periodic and chaotic regions is compared. It is shown that the behavior of this series in the chaotic and in the periodic regimes is entirely different. The changes of the asymmetry coefficients for the periodic cases are very regular and for the chaotic ones - random. In periodic cases, the coefficients converge to zero when the length of the distribution increases.
Źródło:
Acta Physica Polonica A; 2009, 116, 6; 987-991
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Asymmetry Coefficients as Indicators of Chaos: Hyperchaotic Qi System
Autorzy:
Wąż, P.
Bielińska-Wąż, D.
Powiązania:
https://bibliotekanauki.pl/articles/1400122.pdf
Data publikacji:
2013-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.70.Rr
95.10.Fh
05.45.-a
05.45.Gg
05.45.Tp
Opis:
Statistical properties of the hyperchaotic Qi system are studied. The theory, recently formulated and applied for the damped driven pendulum, is used in this investigation. Asymmetry coefficients, related to the statistical moments of distributions composed from the time-series, are shown to behave in a different way for periodic, chaotic and hyperchaotic solutions and are proposed as indicators of chaos and hyperchaos.
Źródło:
Acta Physica Polonica A; 2013, 123, 4; 647-650
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Self-Diffusion of Tungsten on Some Facets of Tungsten Microcrystal
Autorzy:
Biernat, T.
Błaszczyszyn, R.
Powiązania:
https://bibliotekanauki.pl/articles/1811508.pdf
Data publikacji:
2008-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.70.+q
68.90.+g
05.40.-a
Opis:
The field emission current fluctuation method was applied to investigate surface self-diffusion of tungsten on the (311) and (711) regions (along the zone line (211)-(100)) of a tungsten microcrystal (in the form of the field emitter tip of radius about 300 nm) in the temperature range 500-850 K. The surface diffusion parameters were obtained from spectral analysis of the current fluctuations. The results are discussed from the aspects of the substrate structure.
Źródło:
Acta Physica Polonica A; 2008, 114, S; S-11-S-16
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quantum Phase Transition in the One-Dimensional XZ Model
Autorzy:
Brzezicki, W.
Oleś, A.
Powiązania:
https://bibliotekanauki.pl/articles/1810415.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.10.Jm
03.67.-a
05.70.Fh
Opis:
We introduce a one-dimensional XZ model with alternating $σ_i^zσ_{i+1}^z$ and $σ_i^x σ_{i+1}^x$ interactions on even/odd bonds, interpolating between the Ising model and the quantum compass model. We present two ways of its exact solution by: (i) mapping to the quantum Ising models, and (ii) using fermions with spin 1/2. In certain cases the nearest neighbor pseudospin correlations change discontinuously at the quantum phase transition, where one finds highly degenerate ground state of the 1D compass model.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 162-164
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Heuristic for Approximating Extreme Negative Price Returns in Financial Markets
Autorzy:
Manhire, J.
Powiązania:
https://bibliotekanauki.pl/articles/1029529.pdf
Data publikacji:
2018-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.70.-c
05.10.-a
89.65.Gh
Opis:
The paper describes the behavior of financial markets as functions of the variables ``price return'' and ``time'' based on the net difference between ask and bid volumes over a unit period, thereby suggesting that at least a negative non-trivial price return extreme exists for a unit period. This admittedly heuristic approach also offers a method for approximating these negative price return extremes for a specific unit period. Limitations and applications are discussed.
Źródło:
Acta Physica Polonica A; 2018, 133, 6; 1408-1413
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Positronium time-of-flight Measurements of Mesoporous Silica Films
Autorzy:
Kuang, Peng
Zhang, Xiao
He, Chun
Cao, Xing
Wang, Bao
Powiązania:
https://bibliotekanauki.pl/articles/1029796.pdf
Data publikacji:
2018-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Bj
61.05.-a
68.47.Mn
Opis:
Mesoporous silica films were synthesized with various concentrations of cetyltrimethylammonium bromide (CTAB) in precursor sols through the method of electro-assisted self-assembly (EASA). Oriented pore channels were observed in the films prepared with more CTAB in the precursor sols. Positronium time-of-flight (Ps-TOF) measurements were performed for the silica films with different porous structures. It is demonstrated that the Ps emission intensity and energies are well correlated to the apparent porosity, pore interconnectivity and possibly pore channel orientation. The results indicate that Ps-TOF can be a useful technique for probing the structures of porous films.
Źródło:
Acta Physica Polonica A; 2018, 133, 1; 3-6
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mutual Information-Based Hierarchies on Warsaw Stock Exchange
Autorzy:
Fiedor, P.
Powiązania:
https://bibliotekanauki.pl/articles/1388360.pdf
Data publikacji:
2015-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.10.-a
64.60.aq
89.65.-s
89.70.-a
Opis:
A popular method for network analysis of financial markets is a notable part of econophysics research. The networks created in such efforts are focused exclusively on linear correlations between stocks. While Pearson's correlation is the obvious starting point, it would be useful to look at its alternatives as to whether they provide improvements to this methodology, particularly given Pearson's correlation coefficient considers only a limited class of association patterns. We propose to use mutual information-based hierarchical networks, as mutual information is a natural generalisation of Pearson's correlation. We estimate mutual information using naive plug-in estimator as consistent bias is not harmful to this application, however other methods may also be used. We then transform the mutual information into an Euclidean metric and create minimal spanning trees and maximally filtered planar graphs. We apply this methodology to Warsaw Stock Exchange for years between 2000 and 2013, and comment on the differences with the standard methodology, as well as the structural changes on Warsaw Stock Exchange which the study reveals.
Źródło:
Acta Physica Polonica A; 2015, 127, 3A; A-33-A-37
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Granger Causality and Transfer Entropy for Financial Returns
Autorzy:
Syczewska, E.
Struzik, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1388215.pdf
Data publikacji:
2015-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
89.20.-a
89.70.Cf
02.50.-r
05.45.Tp
02.70.Rr
Opis:
Granger causality in its linear form has been shown by Barnett, Barrett and Seth [Phys. Rev. Lett. 103, 238701 (2009)] to be equivalent to transfer entropy in case of Gaussian distribution. Generalizations by Hlaváčková-Schindler [Appl. Math. Sci. 5, 3637 (2011)] are applied to distributions typical for biomedical applications. The financial returns, which are of great importance in financial econometrics, typically do not have Gaussian distribution. Generalizations leading to the concept of nonlinear Granger causality (e.g. causality in variance, causality in risk), known and applied in econometric literature, seem to be less known outside this field. In the paper an overview of some of the definitions and applications is given. In particular, we indicate some recent econometric results concerning application of the tests in linear multivariate framework. We emphasize importance of other variants of Granger causality, and need of development of methods reflecting features of financial variables.
Źródło:
Acta Physica Polonica A; 2015, 127, 3A; A-129-A-135
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of Glass Transition and Crystallization Behavior in $Ga_{15}Se_{85 - x}Pb_x$ (0 ≤ x ≤ 6) Chalcogenide Glasses
Autorzy:
Khan, Z.
Khan, S.
Alvi, M.
Powiązania:
https://bibliotekanauki.pl/articles/1400308.pdf
Data publikacji:
2013-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.43.Dq
61.05.cp
64.70.p
64.70.dg
65.60.+a
Opis:
There has been a growing interest in the synthesis and characterization of amorphous chalcogenide glasses due to their importance in preparing electronic memories, grating, switching devices and their optical applications as good IR transmitting materials. The study of the glass transformations and crystallization processes in the amorphous systems is interesting not only from the fundamental aspect of establishing the reaction mechanism of crystal nucleation and growth, but also from a technological point of view. The present research work is concentrated on the study of glass transition and crystallization behavior in $Ga_{15}Se_{85 - x}Pb_x$ with x=0, 3, and 6 chalcogenide glasses by differential scanning calorimetry. Their amorphous nature has been verified by X-ray diffraction. The differential scanning calorimetry experiments were performed at different continuous heating rates (5 to 25 K/min). The glass transition temperature (T_{g}) and crystallization temperature $(T_{c})$ of these glasses has been determined from differential scanning calorimetry thermograms. The dependence of $T_{g}$ and $T_{c}$ on the heating rate (β) has been used for the determination of different crystallization parameters such as the activation energy of crystallization (Δ $E_{c}$), the activation energy for structural relaxation (Δ $E_{t}$) and the order parameter (n). The results of crystallization were discussed on the basis of different models such as Kissinger's approach and modification for non-isothermal crystallization in addition to Johnson, Mehl, Ozawa and Avrami.
Źródło:
Acta Physica Polonica A; 2013, 123, 1; 80-86
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of different SU(3) color representations on the nucleation of quark-gluon plasma droplets from a hadronic gas
Autorzy:
Mezouar, K.
Ait El Djoudi, A.
Powiązania:
https://bibliotekanauki.pl/articles/1070450.pdf
Data publikacji:
2016-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
12.38.Mh
64.60.Qb
02.20.-a
05.70.Ce
Opis:
We study the nucleation of quark-gluon plasma (QGP) droplets from the hadronic gas phase, based on the calculation of the difference in free energy in the QGP and hadronic gas phases. We investigate this difference in free energy by modeling it in different cases, when the surface tension of the QGP bubble is considered or not. We calculate the free energies of both hadronic gas consisting of massive pions and plasma droplet with up, down and strange quarks additionally to gluons, for different SU ≤ft( 3 ıght) color representations of the QGP, namely the color singlet, color octet, and color 27-plet. The behavior of the obtained change in free energy is examined with varying radius of the QGP bubble, and at different temperatures. The effect of the surface contribution on the nucleated bubble is also investigated and compared to the case without this contribution.
Źródło:
Acta Physica Polonica A; 2016, 130, 1; 202-205
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photoinduced $sp^3$ Nanosize Domain with Frozen Shear Displacement in Graphite
Autorzy:
Nishioka, K.
Nasu, K.
Powiązania:
https://bibliotekanauki.pl/articles/1490002.pdf
Data publikacji:
2012-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.70.Nd
61.48.Gh
31.15.xv
05.40.-a
Opis:
A novel $sp^3$-bonded nanosize domain, known as a diaphite which is an intermediate state between a graphite and a diamond, is generated by the irradiation of visible laser pulse onto a graphite crystal. The $sp^3$ structure is well stabilized by shear displacement between neighboring graphite layers. We theoretically study the interlayer $sp^3$ bond formation with frozen shear displacement in a graphite crystal, using a classical molecular dynamics and a semi-empirical Brenner potential. We show that a pulse excitation under the fluctuation of shearing motion of carbons in an initial state can generate interlayer $sp^3$ bonds which freeze the shear, though no frozen shear appears if there is no fluctuation initially. Moreover, we investigate a pulse excitation under the coherent shearing motion and consequently obtain that the $sp^3$-bonded domain with frozen shear is efficiently formed. We conclude that the initial shear is important for the photoinduced $sp^3$ nanosize domain formation.
Źródło:
Acta Physica Polonica A; 2012, 121, 2; 350-354
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of CaO Addition on the Sintering Behaviour of Anorthite Formed from Kaolin and CaO
Autorzy:
Ouali, A.
Sahnoune, F.
Belhouchet, H.
Heraiz, M.
Powiązania:
https://bibliotekanauki.pl/articles/1032557.pdf
Data publikacji:
2017-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Je
81.05.Mh
81.20.Ev
81.70.Pg
65.40.De
65.60.+a
Opis:
Thermal reactions and sintering behavior of kaolin DD3 (Djebel Debbagh, Algeria) and CaO mixtures to obtain dense anorthite ceramics were investigated. Mixed powders were uniaxially pressed and fired between 850 and 1150°C. Firing the pressed specimens yielded a dense anorthite ceramics. The sintered density increased with increase of CaO content and reached the maximum value of 2.57 g/cm³ for the composition containing 10 wt% CaO and fired at 1150°C. Their coefficient of linear expansion of the sintered samples at 1100°C decreases with the addition of CaO. X-ray diffraction experiments carried out on the samples containing varied amount of CaO and fired at the temperatures higher than 1000°C for 2 h showed the presence of only anorthite phase.
Źródło:
Acta Physica Polonica A; 2017, 131, 1; 159-161
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Long-Term Dependences on Hard Drives Performance during Human Computer Interaction
Autorzy:
Strzałka, D.
Powiązania:
https://bibliotekanauki.pl/articles/1398898.pdf
Data publikacji:
2016-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
89.20.Ff
89.20.Kk
89.70.-a
89.75.-k
05.20.-y
Opis:
Today, computer systems become one of the most important systems in technology and our life. They have a plenty of possible applications but most of them can be described as a transformation of (electrical) energy into useful work = calculations. This process is not so simple as it seems to be because the structure of computers hardware is very complicated and processed tasks are also very complex. Because the expectations of computer users are very high, a lot of computer resources are used only for operating systems normal work. Some existing solutions, especially in the memory system, guarantee that computer systems have acceptable performance but this parameter depends on many important system features. In this paper we will focus on one parameter, namely average disk time s/ transfer, in order to show the complex behavior of this memory system part during man-computer interaction. This is one of the most important counters in computer systems that works under Windows family operating systems and describes measurement related to hard drive based on the complete roundtrip time of any request.
Źródło:
Acta Physica Polonica A; 2016, 129, 5; 1064-1070
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Low Temperature Crystal Structure Behaviour of Complex Yttrium Aluminium Oxides YAlO_3 and Y_3Al_5O_{12}
Autorzy:
Senyshyn, A.
Vasylechko, L.
Powiązania:
https://bibliotekanauki.pl/articles/1399474.pdf
Data publikacji:
2013-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.66.Fn
61.05.F-
65.40.De
65.60.+a
63.70.+h
Opis:
Crystal structures of two yttrium aluminium oxides, namely $YAlO_3$ and $Y_3Al_5O_{12}$, were investigated in the temperature range 3.4-300 K by high-resolution neutron powder diffraction. Neither traces of phase transformations nor discontinuous changes of physical properties were observed. Thermal expansion of yttrium aluminium oxides was evaluated in terms of 1st order Grüneisen approximation, where the Debye temperatures and the Grüneisen parameters have been estimated for both compositions. Anomalies in the thermal expansion of yttrium aluminium perovskite have been observed and modelled using the Einstein oscillator with negative Grüneisen parameter. Extended bond length analysis revealed significant thermally-driven modifications of the aluminium-oxygen framework.
Źródło:
Acta Physica Polonica A; 2013, 124, 2; 329-335
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Toy Model for Large Non-Symmetric Random Matrices
Autorzy:
Snarska, M.
Powiązania:
https://bibliotekanauki.pl/articles/1812225.pdf
Data publikacji:
2008-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.05.Sk
02.70.Hm
89.65.Gh
02.50.-r
89.20.-a
Opis:
Non-symmetric rectangular correlation matrices occur in many problems in economics. We test the method of extracting statistically meaningful correlations between input and output variables of large dimensionality and build a toy model for artificially included correlations in large random time series.The results are then applied to analysis of polish macroeconomic data and can be used as an alternative to classical cointegration approach.
Źródło:
Acta Physica Polonica A; 2008, 114, 3; 555-559
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exact Diagonalization Study of an Extended Hubbard Model for a Cubic Cluster at Quarter Filling
Autorzy:
Szałowski, K.
Balcerzak, T.
Jaščur, M.
Bobák, A.
Žukovič, M.
Powiązania:
https://bibliotekanauki.pl/articles/1032794.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.40.Cx
75.75.-c
75.10.Lp
71.27.+a
65.80.-g
05.70.Ce
Opis:
In the paper the thermodynamics of a cubic cluster with 8 sites at quarter filling is characterized by means of exact diagonalization technique. Particular emphasis is put on the behaviour of such response functions as specific heat and magnetic susceptibility. The system is modelled with extended Hubbard model which includes electron hopping between both first and second nearest neighbours as well as Coulombic interactions, both on-site and between nearest-neighbour sites. The importance of hopping between second nearest neighbours and Coulombic interactions between nearest neighbours for the temperature dependences of thermodynamic response functions is analysed. In particular, the predictions of the Schottky model are compared with the calculations based on the full energy spectrum.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 1012-1014
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
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