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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:
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:
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:
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:
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:
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:
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:
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:
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:
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:
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:
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:
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:
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:
Olivine Particle Reinforced Polyphenylene Sulfide Matrix Composites
Autorzy:
Sahin, A.
Sinmazcelik, T.
Powiązania:
https://bibliotekanauki.pl/articles/1031954.pdf
Data publikacji:
2017-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Qk
81.05.Zx
81.70.Bt
Opis:
Polyphenylene sulfide is a semicrystalline thermoplastic polymer. It offers an excellent balance of properties, including chemical resistance, high temperature resistance, dimensional stability, electrical characteristics and flowability. Polyphenylene sulfide must be filled with reinforced agents, such as fibers and fillers, to overcome its inherent brittleness. Because of its low viscosity, polyphenylene sulfide can be molded with high loading of fillers and reinforcements. These fillers and reinforcements will make a difference in the electrical properties, strength, dimensional stability, surface properties and overall cost. Because of its inherent flame retardancy, polyphenylene sulfide is ideal for high temperature electrical applications. On the other hand, olivine is volcanic based mineral with porous structure, which consists of forsterite (Mg₂SiO₄) and fayalite (Fe₂SiO₄). Both, its lower price compared to other minerals and harmlessness to human health increase the usage of olivine from day to day. For this reason olivine reinforced polyphenylene sulfide composite samples were manufactured at various weight ratios (0, 1, 3, 5 and 10 wt.%). Mechanical and scratch properties of samples were investigated and according to test results, it is concluded that olivine mineral can be used as a reinforcing agent material instead of other conventional fillers.
Źródło:
Acta Physica Polonica A; 2017, 131, 3; 481-483
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:
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:
Fractals, Log-Periodicity and Financial Crashes
Autorzy:
Oświęcimka, P.
Drożdż, S.
Kwapień, J.
Górski, A.
Powiązania:
https://bibliotekanauki.pl/articles/1538497.pdf
Data publikacji:
2010-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
52.35.Mw
05.45.Df
05.70.Jk
Opis:
Presence of self-similar patterns in the financial dynamics is by now well established and even convincingly quantified within the multifractal formalism. Here we focus attention on one particular aspect of this self-similarity which potentially is related to the discrete-scale invariance underlying the system composition and manifests itself by the log-periodic oscillations cascading self-similarly through various time scales. Such oscillations accumulate at the turning (critical) points that in the financial dynamics are often identified as crashes. This property thus allows us to develop a methodology that may be useful also for prediction. A model Weierstrass-type function is used to illustrate the relevant effects and several examples demonstrating that such effects in the real financial markets take place indeed, are reviewed.
Źródło:
Acta Physica Polonica A; 2010, 117, 4; 637-639
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Critical Sound Attenuation and Spin-Lattice Relaxation
Autorzy:
Pawlak, A.
Powiązania:
https://bibliotekanauki.pl/articles/1930585.pdf
Data publikacji:
1994-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.70.Jk
62.65.+k
Opis:
The nonasymptotic critical properties of sound propagation are studied in compressible magnetic system. The role of coupling of order parameter and acoustic phonons to spin-energy density is investigated and the ultrasonic attenuation scaling function is found.
Źródło:
Acta Physica Polonica A; 1994, 85, 2; 385-387
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:
Magnetic Field Dependence of Critical Attenuation in Ferromagnet
Autorzy:
Pawlak, A.
Powiązania:
https://bibliotekanauki.pl/articles/1427558.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.70.Jk
62.65.+k
Opis:
The influence of magnetic field on the sound attenuation is investigated in ferromagnets. With the aid of the Nelson method we derive frequency-, magnetic field- and temperature-dependent expression for the sound attenuation coefficient near a critical point in the Ising-type system. The shift of the ultrasonic attenuation peak under the influence of magnetic field towards higher temperatures is discussed.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1185-1187
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin-Lattice Relaxation Effects in Critical Sound Propagation
Autorzy:
Pawlak, A.
Powiązania:
https://bibliotekanauki.pl/articles/1964802.pdf
Data publikacji:
1997-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
62.65.+k
05.70.Jk
Opis:
The nonasymptotic critical properties of sound propagation are studied in compressible Ising system above T$\text{}_{C}$. In the present paper we analyse a model where in addition to the coupling to two order-parameter fluctuations the sound mode couples linearly to the fluctuations of spin-energy and lattice-energy densities. Both subsystems exchange energy with the rate determined by the bare spin-lattice relaxation time. The total energy may be conserved or not. The crossover between insulator-like behaviour ~t$\text{}^{-2α}$ and metal-like behaviour ~t$\text{}^{-(zν+α)}$ in ultrasonic attenuation is investigated according to the value of ultrasonic frequency, the reduced temperature t, bare relaxation times and various coupling constants.
Źródło:
Acta Physica Polonica A; 1997, 92, 2; 449-452
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Complexes of Domain Walls in Ferromagnetic Stripes
Autorzy:
Janutka, A.
Powiązania:
https://bibliotekanauki.pl/articles/1399260.pdf
Data publikacji:
2013-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.45.Yv
75.70.Kw
75.75.Jn
75.78.Fg
85.70.Kh
Opis:
Interaction of domain walls in ferromagnetic stripes is studied with relevance to the formation of stable complexes of many domains. Two domain wall system is described with the Landau-Lifshitz-Gilbert equation including regimes of narrow and wide stripes which correspond the presence of transverse and vortex domain walls. The domain walls of both kinds are characterized with their chiralities (the direction of the magnetization rotation in the stripe plane) and polarities (the magnetization orientation in the center of a vortex and/or halfvortices), hence, their interactions are analyzed with dependence on these properties. In particular, pairs of the domain walls of opposite or like chiralities and polarities are investigated as well as pairs of opposite (like) chiralities and of like (opposite) polarities. Conditions of the creation of stationary bubbles built of two interacting domain walls are formulated with relevance to the situations of presence and absence of the external magnetic field.
Źródło:
Acta Physica Polonica A; 2013, 124, 4; 641-648
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Critical Sound Propagation in Magnetic Metals and Bottleneck Phenomena
Autorzy:
Pawlak, A.
Powiązania:
https://bibliotekanauki.pl/articles/2013730.pdf
Data publikacji:
2000-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.70.Jk
62.65.+k
Opis:
A semiphenomenological model of sound propagation in a critical magnetic system is proposed, which takes into account a relaxation of energy between the system of localised spins and the conduction electron spins as well as the coupling of the longitudinal phonon to bilinear combination of spin fluctuations and to the energy densities. A general expression for the acoustic self-energy is obtained within the one-loop approximation. The effect of "bottlenecking" and its influence on the critical singularities in the sound characteristics is discussed.
Źródło:
Acta Physica Polonica A; 2000, 97, 5; 909-912
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theory of Critical Sound Attenuation in Ising-Type Magnets
Autorzy:
Pawlak, A.
Powiązania:
https://bibliotekanauki.pl/articles/2014046.pdf
Data publikacji:
2000-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
62.65.+k
05.70.Jk
Opis:
The critical behaviour of sound attenuation has been studied in an elastically isotropic Ising system above the critical point on the basis of a complete stochastic model including both spin-energy and lattice-energy modes linearly coupled to the longitudinal sound mode. The effect of spin-lattice relaxation on the ultrasonic attenuation is investigated. The crossover between Kawasaki behaviour and Murata-Iro-Schwabl behaviour is studied as dependent on the values of ultrasonic frequency, reduced temperature, relaxation times, etc. A new high-frequency regime is discussed in the magnetic systems. This new regime corresponds to an adiabatic sound propagation and is very similar to the ones in binary mixture and liquid helium. A new frequency-dependent specific heat being the harmonic average of the bare lattice and critical spin specific heats is introduced. It was shown that such specific heat describes the process of equilibration between spin and lattice subsystems and includes the most important features of critical sound attenuation.
Źródło:
Acta Physica Polonica A; 2000, 98, 1-2; 23-39
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fabrication of Superhydrophilic Polyester Fabrics Using Various TiO₂ Colloidal Dispersions
Autorzy:
Ojstršek, A.
Kurečič, M.
Fakin, D.
Powiązania:
https://bibliotekanauki.pl/articles/1401222.pdf
Data publikacji:
2015-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Lg
81.70.Fy
82.70.Dd
Opis:
The purpose of this research was to apply four stable colloidal dispersions, combining different TiO₂ core-shell nanoparticles, onto polyester fabric, according to exhaustion procedure, in order to enhance fabrics' water and moisture absorption properties. Firstly, all colloidal dispersions were analysed using transmission electron microscopy (TEM) and dynamic light scattering (DLS) and secondly, the morphologies of TiO₂ modified PES surfaces were evaluated by scanning electron microscopy (SEM). In addition, the superhydrophilic character of fibrous surfaces was investigated by water contact angle measurement. For this purpose, dynamic tensiometry was employed by measuring the changes in the net force on a surface during the repeated immersion and emersion of a solid into a probe liquid. The obtained results show excellent wettability of TiO₂ upgraded PES fabrics depending on the type of applied nano-sized TiO₂-hybride.
Źródło:
Acta Physica Polonica A; 2015, 127, 4; 953-956
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:
Annihilation of o-Positronium in the Vicinity of the Critical Mixing Point
Autorzy:
Jerie, K.
Baranowski, A.
Gliński, J.
Orzechowski, K.
Powiązania:
https://bibliotekanauki.pl/articles/2008045.pdf
Data publikacji:
1999-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.70.Jk
78.70.Bj
Opis:
Positron annihilation spectra were investigated in the critical region close to the consolute point of ethanol + dodecane mixture. The anomalies of the positron lifetimes and intensities were small, nevertheless it was found that the intensity of short-living components of annihilation spectrum seems to increase close to the critical temperature.
Źródło:
Acta Physica Polonica A; 1999, 95, 4; 569-574
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performance Analysis of a Dual Cycle Engine with Considerations of Pressure Ratio and Cut-Off Ratio
Autorzy:
Ebrahimi, R.
Powiązania:
https://bibliotekanauki.pl/articles/1535596.pdf
Data publikacji:
2010-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.70.Ln
82.60.Fa
88.05.-b
Opis:
The dual cycle is a better approximation to the modern high speed compression ignition engine than either the Diesel cycle or the Otto cycle. Therefore, this study is aimed at investigating the effects of pressure and cut-off ratios on the dual cycle performance with considerations of heat transfer loss, variable specific heat ratio and friction irreversible losses. By using finite-time thermodynamics theory, the relations between the power output and the compression ratio, between the thermal efficiency and the compression ratio, as well as the optimal relation between power output and the efficiency of the cycle are obtained. The results show that if compression ratio is smaller than certain value, the increase of pressure ratio and the decrease of cut-off ratio make the power output bigger. While if compression ratio exceeds certain value, the power output first increases and then starts to decline as pressure ratio and cut-off ratio are increased. With further increase in compression ratio, the power output decreases with increasing pressure ratio and decreasing cut-off ratio. The effects of pressure and cut-off ratios on the variation of the thermal efficiency with compression ratio are similar to those for the power output. The results obtained in this work can provide significant guidance for the performance evaluation and improvement of modern high speed compression ignition engines.
Źródło:
Acta Physica Polonica A; 2010, 118, 4; 534-539
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Order in Quantum Compass and Orbital e_{g} Models
Autorzy:
Czarnik, P.
Dziarmaga, J.
Oleś, A.
Powiązania:
https://bibliotekanauki.pl/articles/1029762.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.10.Jm
05.10.Cc
05.70.Fh
75.25.Dk
Opis:
We investigate thermodynamic phase transitions in the compass model and in e_{g} orbital model on an infinite square lattice by variational tensor network renormalization (VTNR) in imaginary time. The onset of nematic order in the quantum compass model is estimated at _{c}/J=0.0606(4). For the e_{g} orbital model one finds: (i) a very accurate estimate of _{c}/J=0.3566± 0.0001 and (ii) the critical exponents in the Ising universality class. Remarkably large difference in frustration results in so distinct values of _{c}, while entanglement influences the quality of _{c} estimation.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 359-361
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical Bistability Induced by Additive Colored Noise in the Exciton-Biexciton System
Autorzy:
Gonţia, I. I.
Rotaru, A. H.
Powiązania:
https://bibliotekanauki.pl/articles/1933412.pdf
Data publikacji:
1995-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.40.+j
05.70.Fh
42.65.Pc
Opis:
This paper predicts optical bimodality induced by external additive noise with a finite bandwidth, in the exciton-biexciton system.
Źródło:
Acta Physica Polonica A; 1995, 87, 6; 911-917
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Field Effect on Sound Propagation in Antiferromagnets
Autorzy:
Pawlak, A.
Fechner, B.
Powiązania:
https://bibliotekanauki.pl/articles/1810483.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.70.Jk
62.65.+k
Opis:
On the basis of the theory of phase transitions, a model describing anomalies of sound attenuation coefficient close to the antiferromagnet-paramagnet phase transition in magnetic field was developed. The scaling behaviour of the sound velocity and attenuation coefficient was determined. The physical origin of the two-peak structure in the field dependent ultrasound attenuation observed in a number of antiferromagnets was identified. The theoretical results were compared with experimental results obtained for terbium.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 232-234
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:
A Finite-Element Flash Method for Measuring Thermal Conductivity of Liquid
Autorzy:
Mamczur, J.
Wasilewski, A.
Więcek, T.
Powiązania:
https://bibliotekanauki.pl/articles/1402572.pdf
Data publikacji:
2015-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
44.05.+e
44.10.+i
07.05.Tp
02.70.Dh
02.60.Ed
Opis:
A laser beam is used to heat a portion of liquid closed in a vessel from the top of it to avoid convection. The temperature is measured at the bottom of the vessel by a laser waveguide sensor. The heating and measuring methods allow using a small amount of liquid of the order of a milliliter fraction. The heat flow through the liquid as well as the surrounding vessel and space is modeled by the finite-element method to calculate the temperature at the bottom vs. time. Thus obtained dependence is used then as a fitting function to get the liquid thermal conductivity among some other fitting parameters.
Źródło:
Acta Physica Polonica A; 2015, 128, 2; 193-195
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanical Properties of Aluminum-Matrix-Nanoparticle Composites
Autorzy:
Kazakewitsch, A.
Riehemann, W.
Powiązania:
https://bibliotekanauki.pl/articles/1418512.pdf
Data publikacji:
2012-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.82.Rx
62.40.+i
81.05.-t
81.05.Ni
81.07.Wx
81.20.Ev
81.20.Hy
81.40.Ef
81.70.-q
81.70.Bt
Opis:
Aluminum-matrix-nanoparticle composites were produced by ball milling of micro scale aluminum powder with different additions of 500 nm mean diameter SiC particles in air atmosphere with subsequent consolidation by hot extrusion. The material was investigated in this condition by tensile testing, hot tensile testing, density, hardness, and amplitude dependent damping measurements. The amplitude dependent damping of the material was investigated after slow furnace heating and cooling as after quenching into water to the room temperature. The results of the tensile and hot tensile testing show that the addition of SiC particles lead to a significant increase of tensile strength, but the remaining porosity increased, too. The results obtained for the amplitude dependent damping can be attributed to cracks present in the consolidated material or cracks produced by thermal stresses.
Źródło:
Acta Physica Polonica A; 2012, 122, 3; 516-519
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:
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:
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:
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:
Development of a Polymer Based Syntactic Foam for High Temperature Applications
Autorzy:
Yazici, M.
Fahr, P.
Shukla, A.
Gunes, S.
Akay, S.
Powiązania:
https://bibliotekanauki.pl/articles/1182911.pdf
Data publikacji:
2014-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Qk
81.70.Bt
81.40.-z
81.05.Lg
Opis:
Syntactic foams are one of the most widely used close cell structured foams. They are used in applications for naval, aeronautical, aerospace, civil, industrial, and automotive engineering due to good acoustical attenuation, excellent strength to weight ratio, vibration isolation, and dielectric properties. These foams are fabricated by incorporation of hollow particles in a matrix material. The most preferred matrix materials are polymers. In this study silicone resin (useful temperature range - 53C to 232°C) was selected as a binder material. Glass bubbles were incorporated into the silicone resin at three different mass percentages (10%, 20%, and 30%). The density of the silicone was reduced more than 50% by 30% glass bubble contribution. The foam mechanical properties were investigated in a room temperature and after heat treatment at 500C by quasi-static compression experiments. Microstructural transitions by the temperature raises were examined by using scanning electron microscopy pictures. It was observed that the increase of glass bubble percentage in silicone rubber enhanced the energy absorption properties in the heat treated and room temperature specimens. Plateau stress and densification amount were improved under quasi-static compression load by the glass bubble percentage increase. It can be said that developed syntactic foams can be used in heat resistant, low weight and high compression strength exigencies.
Źródło:
Acta Physica Polonica A; 2014, 125, 2; 526-528
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Power Optimization of a Miller Thermal Cycle with respect to Residual Gases and Equivalence Ratio
Autorzy:
Ebrahimi, R.
Powiązania:
https://bibliotekanauki.pl/articles/1399491.pdf
Data publikacji:
2013-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.70.Ln
82.60.Fa
88.05.-b
88.20.td
Opis:
The performance of an air standard Miller cycle is analyzed using finite-time thermodynamics. The relations between the power output and the compression ratio and between the power output and the thermal efficiency are derived by detailed numerical examples. The results show that, throughout the compression ratio range, the power output decreases with increasing residual gases. The results also show that if compression ratio is less than certain value, the power output decreases with increasing equivalence ratio, while if compression ratio exceeds certain value, the power output first increases and then starts to decrease with increasing equivalence ratio. The conclusions of this investigation are of importance when considering the designs of actual Miller engines.
Źródło:
Acta Physica Polonica A; 2013, 124, 1; 6-10
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Enhanced Mechanical Performance of Aluminum Glass Fiber Reinforced Foam Material by Cu Modification
Autorzy:
Ertürk, A.
Aydin, I.
Powiązania:
https://bibliotekanauki.pl/articles/1033530.pdf
Data publikacji:
2017-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Bx
81.05.Rm
81.20.Ev
81.70.Bt
Opis:
Glass fiber-reinforced aluminum foam and its modified forms, using 1 and 3 wt.% of Cu, were produced by powder sintering process, using spherical carbamide particles as space holders. The foams with 40 and 60 vol.% porosity fractions were successfully produced after water leaching and sintering procedures. Compression test was performed on foam samples to compare both, the compressive properties and energy absorption behavior of them. The composite foam samples with Cu modification have shown a higher compressive strength than the parent material foam. The average plateau stress and energy absorption capacity of foams produced in this study, achieved via utilizing 3 wt.% Cu, were 7.06 MPa and 3.51 MJ/m³, respectively.
Źródło:
Acta Physica Polonica A; 2017, 131, 3; 470-473
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of Pre-Forming Process and PVC Foam Reinforcement on the Deformation Behavior of Aluminum Tube under Axial Loading
Autorzy:
Ekşi, S.
Kapti, A.
Genel, K.
Powiązania:
https://bibliotekanauki.pl/articles/1031785.pdf
Data publikacji:
2017-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.-t
81.05.Bx
81.05.Rm
81.40.Lm
81.70.-q
81.05.Pj
Opis:
In this study, the effects of pre-forming and foam reinforcement on the axial compression behavior of circular thin-walled aluminum tubes were experimentally investigated. Compression tests were performed in a computer controlled test machine at the cross-head speed of 1 mm/s. Pre-forming has changed the folding behavior of tube and increased the energy absorbing capacity 1.26 times that of empty tube. The PVC reinforcement has increased the energy absorbing capacity 1.22 times. PVC reinforcement increases the stability of tube wall deformation; hence it positively affects the energy absorption. The energy absorbing capacity of pre-formed and PVC foam reinforced tubes increase approximately 1.4 times that of empty tube. It was however shown that the reinforcement and pre-forming had no significant effect on the maximum load.
Źródło:
Acta Physica Polonica A; 2017, 132, 3; 875-878
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Production of Aluminum Glass Fiber Reinforced Foam Synthesized by Space-Holder Technique
Autorzy:
Ertürk, A.
Powiązania:
https://bibliotekanauki.pl/articles/1187253.pdf
Data publikacji:
2016-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Rm
81.05.Bx
83.80.Ab
81.20.Ev
81.70.Bt
Opis:
Aluminum and its reinforced type with glass fiber composite foams were produced by powder sintering process using spherical carbamide particles as a space holder. The foams with 40-60 vol.% porosity fractions were successfully produced after water leaching and sintering methods. Compression test was performed on both of the foam samples for comparing the compressive properties and energy absorption behavior of them. The composite foam samples with glass fiber reinforcement showed higher compressive strength than the parent material foam.
Źródło:
Acta Physica Polonica A; 2016, 129, 4; 592-595
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase Diagrams of the Spin-1/2 Ising-Heisenberg Model on a Triangle-Hexagon Lattice
Autorzy:
Kiššová, J.
Strečka, J.
Powiązania:
https://bibliotekanauki.pl/articles/1506906.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.30.Rt
05.50.+q
05.70.Jk
75.10.Kt
75.10.Jm
75.30.Kz
Opis:
Ground-state and finite-temperature phase diagrams of a geometrically frustrated spin-1/2 Ising-Heisenberg model on a triangle-hexagon lattice are investigated within the generalized star-triangle mapping transformation. It is shown that the ground state is constituted by two different spontaneously long-range ordered phases and one disordered spin-liquid phase.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 730-731
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Diffusive Regime for Critical Sound Attenuation and Dispersion in Magnets
Autorzy:
Pawlak, A.
Błaszak, M.
Powiązania:
https://bibliotekanauki.pl/articles/2013731.pdf
Data publikacji:
2000-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.70.Jk
62.65.+k
Opis:
We consider a new regime of sound propagation in magnetic systems above the critical point. On the basis of a general statistical model including a flow of energy between spin and lattice subsystems we found that there is a region of parameters where the sound attenuation and dispersion can be expressed in a similar way as for noncritical systems for which only the heat conduction matters. Contrary to the case of the classical heat diffusion in the critical magnetic system both the specific heat, entering the reduced frequency, as well as the effective amplitude are frequency and temperature dependent reflecting the critical singularities present in the system near its critical point.
Źródło:
Acta Physica Polonica A; 2000, 97, 5; 905-908
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Aperiodicity in Equilibrium Systems: Between Order and Disorder
Autorzy:
van Enter, A.
Powiązania:
https://bibliotekanauki.pl/articles/1203443.pdf
Data publikacji:
2014-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.70.Fh
61.44.Br
02.50.Ey
Opis:
Spatial aperiodicity occurs in various models and materials. Although today the most well-known examples occur in the area of quasicrystals, other applications might also be of interest. Here we discuss some issues related to the notion and occurrence of aperiodic order in equilibrium statistical mechanics. In particular, we consider some spectral characterisations, and shortly review what is known about the occurrence of aperiodic order in lattice models at zero and nonzero temperatures. At the end some more speculative connections to the theory of (spin-)glasses are indicated.
Źródło:
Acta Physica Polonica A; 2014, 126, 2; 621-624
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Field Influence on Critical Sound Attenuation and Velocity Variation in Ferromagnets
Autorzy:
Pawlak, A.
Powiązania:
https://bibliotekanauki.pl/articles/1810482.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.70.Jk
62.65.+k
Opis:
The ultrasound velocity and attenuation are investigated in ferromagnets under an application of magnetic field. In the magnetic field six different characteristic regimes are distinguished instead of traditional two (hydrodynamic and critical) found for the case of zero magnetic field. The mean-field Landau-Khalatnikov theory as well as the scaling predictions are given for each regime. Various critical exponents are identified for these regions and compared with the ultrasonic data for MnP. The shift of the ultrasonic attenuation peak under the influence of magnetic field towards higher temperatures is discussed.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 229-231
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanical and Thermal Properties of Pumice Powder Filled PPS Composites
Autorzy:
Sahin, A.
Yildiran, Y.
Avcu, E.
Fidan, S.
Sinmazcelik, T.
Powiązania:
https://bibliotekanauki.pl/articles/1182862.pdf
Data publikacji:
2014-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Qk
81.70.Bt
81.70.Pg
Opis:
Recently, it is common application to use particle materials as fillers to improve engineering properties and lower the cost of finished product. Pumice powder is cheaper than most of traditional particle fillers, however use of pumice powders as a reinforcing material in composites has not been studied in literature. Hence, in this study we have investigated the mechanical and the thermal properties of pumice powder filled polyphenylenesulphide (PPS) composites. PPS composites were reinforced with pumice powder at different loading rates (0, 1, 3.5, and 10 wt%) and they were manufactured by twin screw extruder and injection molding machine. Thermal properties were investigated by thermogravimetric analysis and differential scanning calorimeter methods. Moreover, mechanical properties such as barcol hardness, tensile strength, and modulus of samples were investigated. Thermal properties of composite samples have varied significantly depending on the loading rate. Also mechanical properties of pumice powder filled PPS composites have showed better results than pure PPS. According to test results both of mechanical and thermal properties of composites have improved with pumice powder reinforcement and it is determined that pumice powders can be used instead of traditional particle fillers.
Źródło:
Acta Physica Polonica A; 2014, 125, 2; 518-520
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Critical Fluctuations and 1/f$\text{}^{α}$-Activity of Neural Fields Involving Transmission Delays
Autorzy:
Hutt, A.
Frank, T. D.
Powiązania:
https://bibliotekanauki.pl/articles/2044577.pdf
Data publikacji:
2005-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.19.La
05.40.Ca
02.30.Ks
05.70.Jk
Opis:
This work studies the stability and the stochastic properties of neural activity evoked by external stimulation. The underlying nonlocal model describes the spatiotemporal response dynamics of neural populations involving both synaptic delay and axonal transmission delay. We show that the linear model recasts to a set of affine delay differential equations in spatial Fourier space. Besides a stability study for general kernels and general external stimulation, the power spectrum of evoked activity is derived analytically in the case of external Gaussian noise. Further applications to specific kernels reveal critical fluctuations at Hopf- and Turing bifurcations and allow the numerical detection of 1/f$\text{}^{α}$fluctuations near the stability threshold.
Źródło:
Acta Physica Polonica A; 2005, 108, 6; 1021-1040
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanical and Tribological Behaviour of Chopped E-Glass Fiber-Reinforced Epoxy Composite Materials
Autorzy:
Ozsoy, N.
Ozsoy, M.
Mimaroglu, A.
Powiązania:
https://bibliotekanauki.pl/articles/1031191.pdf
Data publikacji:
2017-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Qk
07.05.Fb
62.20.Qp
81.70.Bt
Opis:
Chopped E-glass fiber-reinforced epoxy composites (10%, 30% and 50%) were fabricated and their mechanical and tribological behaviour was investigated. Three-point bending tests were performed according to the ASTMD790 and tensile tests were performed according to the ASTMD638 standards. Impact tests and hardness measurements of the composites were also carried out. Wear behaviour of composites was studied using pin on disc wear testing device. The design of experiments approach, using Taguchi method, was employed to analyze the results. Signal-to-noise ratio and analysis of variance were used to determine the influence of parameters on the wear rate and coefficient of friction.
Źródło:
Acta Physica Polonica A; 2017, 132, 3; 852-856
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanical properties of chopped carbon fiber reinforced epoxy composites
Autorzy:
Ozsoy, N
Ozsoy, M.
Mimaroglu, A.
Powiązania:
https://bibliotekanauki.pl/articles/1070471.pdf
Data publikacji:
2016-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Qk
81.70.Bt
Opis:
An experimental study has been carried out to investigate tensile, bending, impact and hardness properties of chopped carbon fiber reinforced epoxy composites. Four different weight fractions (0%, 6%, 8%, 10%) were added as reinforcement to composites. The samples were manufactured by using a special designed mold. Tests were carried out according to the ASTM standards. Results of the tests have shown that hardness increases with the increasing amount of carbon fiber in composites. Tensile, bending and impact performances have increased up to 8% of carbon fiber in the composite and then started to decrease.
Źródło:
Acta Physica Polonica A; 2016, 130, 1; 297-299
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Role of TiO₂ Nanoparticles on the UV Protection Ability and Hydrophilicity of Polyamide Fabrics
Autorzy:
Fakin, D.
Stana Kleinschek, K.
Ojstršek, A.
Powiązania:
https://bibliotekanauki.pl/articles/1401220.pdf
Data publikacji:
2015-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Lg
81.70.Fy
82.70.Dd
Opis:
The focus of this study was to characterize three industrially-prepared (via the sulphate synthesis process) nano-TiO₂ colloidal dispersions with the intention to elucidate their role on the hydrophilicity as well as UV shielding ability when applied onto polyamide fabric. Transmission electron microscopy (TEM) and UV spectrophotometry of the selected dispersions proved the presence of TiO₂ nanoparticles of different shapes and sizes, as well as its imposing absorption capability within the UV region. In addition, TiO₂ dispersions in three concentrations accompanied by selected chemicals and auxiliaries were applied on polyamide fabrics according to standard exhaustion procedure. Scanning electron microscopy (SEM) was adopted in order to analyse the morphological structure of nano-TiO₂-upgraded PA fabrics. Furthermore, the UV-protective ability and hydrophilic properties were evaluated. The gained results show excellent blocking properties against UV-rays (UPF 50+), as well as the (super)hydrophilicity of TiO₂-modified PA fabrics, regarding the type of employed TiO₂ colloidal dispersion.
Źródło:
Acta Physica Polonica A; 2015, 127, 4; 943-946
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effects of Cycle Temperature and Cycle Pressure Ratios on the Performance of an Irreversible Otto Cycle
Autorzy:
Ust, Y.
Sahin, B.
Safa, A.
Powiązania:
https://bibliotekanauki.pl/articles/1493409.pdf
Data publikacji:
2011-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.70.Ln
88.05.-b
88.20.td
Opis:
This paper reports the thermodynamic optimization based on the maximum mean effective pressure, maximum power and maximum thermal efficiency criteria for an irreversible Otto heat engine model which includes internal irreversibility resulting from the adiabatic processes. The mean effective pressure, power output, and thermal efficiency are obtained by introducing the compression ratio, cycle temperature ratio, specific heat ratio and the compression and expansion efficiencies. Optimal performance and design parameters of the Otto cycle are obtained analytically for the maximum power and maximum thermal efficiency conditions and numerically for the maximum mean effective pressure conditions. The results at maximum mean effective pressure conditions are compared with those results obtained by using the maximum power and maximum thermal efficiency criteria. The effects of the cycle temperature ratio and cycle pressure ratio on the general and optimal performances are investigated.
Źródło:
Acta Physica Polonica A; 2011, 120, 3; 412-416
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Study of Time and Space Correlations in Field Emission Current Fluctuations with a Fiber-Optical Technique
Autorzy:
Dadykin, A. A.
Naumovets, A. D.
Powiązania:
https://bibliotekanauki.pl/articles/1892318.pdf
Data publikacji:
1992-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.70.+q
05.40.+j
Opis:
A new technique of measurements of field emission current fluctuations is proposed. The technique uses fiber optics and offers such advantages as the possibility to easily vary the geometry of the probed regions and the distance between them on the field emitter. The correlation functions of field emission current fluctuations have been measured with this technique for O/W(110), H/W(110), Si(111) and Na/Si(111) systems. Some data on surface diffusion coefficients are derived from the measurements.
Źródło:
Acta Physica Polonica A; 1992, 81, 1; 131-143
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Non-Polynomial Spline Method for a Time-Dependent Heat-Like Lane- Emden Equation
Autorzy:
Caglar, S.
Ucar, M.
Powiązania:
https://bibliotekanauki.pl/articles/1491458.pdf
Data publikacji:
2012-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.30.Jr
02.60.Lj
02.70.Bf
02.70.Jn
44.05.+e
Opis:
In this study, a time-dependent heat-like Lane-Emden equation is solved by using a non-polynomial spline method. An example is solved to assess the accuracy of the method. The numerical results are obtained for different values (n) of equation. The results indicate that non-polynomial spline method is effectively implemented. It is seen that results are compatible with exact solutions and consistent with other existing numerical methods.
Źródło:
Acta Physica Polonica A; 2012, 121, 1; 262-264
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:
A Dilute Magnet with Ferro- and Antiferromagnetic Exchange Interactions. The Structural Fluctuations Analysis
Autorzy:
Pikuła, R.
Kirkiewicz, J.
Powiązania:
https://bibliotekanauki.pl/articles/1813493.pdf
Data publikacji:
2008-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.70.Jk
75.30.Kz
Opis:
We analysed the influence of the fluctuations in distribution of magnetic atoms on the properties of dilute magnets with mixed ferro- and antiferromagnetic exchange interactions. The high- and low concentration approximations were found to give very close results and the most important impact on the physical quantities origins from the lowest, square fluctuations which play the predominant role in the whole range of concentrations of magnetic atoms.
Źródło:
Acta Physica Polonica A; 2008, 113, 2; 669-676
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Coherence Properties of Coupled Chaotic Map Lattices
Autorzy:
Janowicz, M.
Orłowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/1492426.pdf
Data publikacji:
2011-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.45.Ra
45.70.Qj
03.75.Hh
03.75.Nt
Opis:
Strong global correlations in the systems of coupled chaotic map lattices based on a modified logistic map are investigated. It is shown that, in the parameter range close to the edge of chaos as defined for an individual map, the systems exhibit off-diagonal long-range order and single-particle reduced density matrices defined in a natural way possess one strongly dominant eigenvalue. In addition, pattern formation [13] in the above systems has been investigated.
Źródło:
Acta Physica Polonica A; 2011, 120, 6A; A-114-A-118
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of On-Site Coulomb Repulsion on Phase Transitions in Exactly Solved Spin-Electron Model
Autorzy:
Gálisová, L.
Strečka, J.
Tanaka, A.
Verkholyak, T.
Powiązania:
https://bibliotekanauki.pl/articles/1534796.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.50.+q
05.70.Jk
64.60.Cn
64.60.De
Opis:
A hybrid lattice-statistical model on doubly decorated planar lattices, which have localized Ising spins at their nodal lattice sites and two itinerant electrons at each pair of decorating sites, is exactly solved by the use of a generalized decoration-iteration transformation. Our main attention is focused on an influence of the on-site Coulomb repulsion on ground-state properties and critical behavior of the investigated system.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 942-943
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Manufacturing of Al-Zr Thermal-resistant Alloys for Transmission Lines
Autorzy:
Erturk, A.
Guven, E.
Karabay, S.
Powiązania:
https://bibliotekanauki.pl/articles/1401363.pdf
Data publikacji:
2015-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Bx
88.80.H
83.50.Uv
81.70.Jb
81.40.Ef
81.70.Bt
Opis:
The present transmission lines of populous cities will have to be changed with an ability to work at higher temperatures without any weight and cross section changes. Innovative thermal-resistant alloy conductors (T-ACSR) operate in the range of about 150-200°C instead of 75°C which is the standard ACSR type conductor service temperature. In this study, the manufacturing procedure of Al-Zr alloy wire, used as high-temperature conductor wires, have been introduced. The Al-Zr alloy has been cast in a permanent mold than being extruded to a diameter of 10 mm at 400°C. After that the extruded rods have been cold drawn to a diameter of 3.02 mm. Elongation and tensile strength values of the cold drawn wire have been achieved by tensile test at elevated temperatures. Also, microstructural analysis and dispersion hardening procedure have been investigated. The results show that tensile strength and thermal-resistant property are improved by the addition of Zr.
Źródło:
Acta Physica Polonica A; 2015, 127, 4; 1292-1294
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase Transitions in (CH$\text{}_{3}$)$\text{}_{2}$ CHNH$\text{}_{3}$CdCl$\text{}_{3}$ Crystal
Autorzy:
Krzewska, U.
Jakubas, R.
Dacko, S.
Czapla, Z.
Waśkowska, A.
Powiązania:
https://bibliotekanauki.pl/articles/1920518.pdf
Data publikacji:
1992-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.70.Kb
05.70.Fh
77.20.+y
Opis:
The crystal of (CH$\text{}_{3}$)$\text{}_{2}$CHNH$\text{}_{3}$CdCl$\text{}_{3}$ was grown and its physical properties were investigated. On the ground of DSC, dylatometric and dielectric investigations the phase transition at 390 K on heating process was revealed. On cooling two phase transitions at 382 K and 352 K were found. Polarized microscope observations show appearance of ferroelastic domain structure and cracks at 390 K on heating. On cooling the observed domain structure vanishes at 352 K.
Źródło:
Acta Physica Polonica A; 1992, 81, 3; 379-384
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:
Calorimetric and Positron Lifetime Measurements οf Hydrogenated Carbon Nanocones
Autorzy:
Budziak, A.
Dryzek, J.
Krawczyk, J.
Zieliński, P.
Powiązania:
https://bibliotekanauki.pl/articles/1538290.pdf
Data publikacji:
2010-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.U-
78.70.Bj
Opis:
Two carbon nano-structured samples containing 5 and 20% of carbon nanocones in their volume were investigated. Using the Sieverts apparatus the hydrogen was loaded into the samples. The measurements of heat capacity in the temperature range from 100 K to 320 K and the positron lifetime measurements at the room temperature were performed for hydrogenated and non-hydrogenated carbon nanocones. The desorption of hydrogen at the temperature of 230 K is deduced from the heat capacity measurements. The detection of the positronium, the bound state of positron and electron, in the measured samples reveals the presence of open volume defects of ca. 0.198 ± 0.002 nm.
Źródło:
Acta Physica Polonica A; 2010, 117, 4; 574-577
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Monte Carlo Studies of the p-Spin Models οn Scale-Free Hypernetworks
Autorzy:
Krawiecki, A.
Powiązania:
https://bibliotekanauki.pl/articles/1400177.pdf
Data publikacji:
2013-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
89.75.-k
89.75.Hc
05.70.Fh
Opis:
Results of Monte Carlo simulations of p-spin models on scale-free hypernetworks are presented. The hypernetworks are obtained using the preferential attachment algorithm, the spins are located in the nodes and the hyperedges connecting p nodes correspond to non-zero ferromagnetic interactions involving p spins. Such models show high degeneracy of the ground state: apart from the ferromagnetic state, depending on the parameters of the preferential attachment algorithm leading to different topologies of the obtained hypernetworks, there are several or even infinitely many disordered (glassy) states with the same energy. For various network topologies quantities such as the specific heat or magnetic susceptibility show maxima as functions of the temperature, which suggests the occurrence of the glassy or ferromagnetic phase transition. The models under study may serve as a starting point for modelling various forms of cooperation in social and economic sciences involving many-body rather than two-body interactions.
Źródło:
Acta Physica Polonica A; 2013, 123, 3; 564-566
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of Mechanical Behaviour of Carbon and Glass Fiber Reinforced Epoxy Composites
Autorzy:
Ozsoy, N.
Mimaroğlu, A.
Ozsoy, M.
Powiązania:
https://bibliotekanauki.pl/articles/1401276.pdf
Data publikacji:
2015-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Qk
81.70.Bt
Opis:
An experimental study has been carried out to investigate tensile and bending properties of carbon fiber (CFRE) and glass fiber-reinforced (GFRE) epoxy composites. Three different fiber orientations were applied, 0°, 90° and [0°, 90°]. The laminates were obtained by manual lay-up process. The samples were evaluated by tensile tests according to the ASTM D3039 and bending tests according to the ASTM D790. Experimental results showed that maximum tensile strengths were observed at 0° fiber direction for the both CFRE and GFRE composites. With respect to their tension properties, the CFRE samples had better performance than the GFRE samples, except for the 90° orientation. Three point bending tests proved that in all orientations CFRE composites had better performance, compared to GFRE composites.
Źródło:
Acta Physica Polonica A; 2015, 127, 4; 1032-1034
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design of a Single Line Half Duplex Protocol for Mechanical Rotary Table Systems
Autorzy:
Ozkan, S.
Atali, G.
Boru, B.
Karayel, D.
Powiązania:
https://bibliotekanauki.pl/articles/1031133.pdf
Data publikacji:
2017-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.05.Hd
07.50.-e
89.70.Hj
07.05.Dz
45.80.+r
Opis:
In this study, a new communication protocol, which addresses the rotary table, has been designed. Developed system works over a single line and is using slip rings. The designed communication protocol ensures the half duplex communication for multiple stations over a single cable. During the protocol design, media access methods, coding techniques and multi-node synchronization techniques were examined. These techniques have been adapted, updated and combined for the study, during the formation of the communication protocol. The designed protocol was tested and verified in the simulation environment with original software, on the microcontrollers. The protocol is aimed to be open source, flexible, easily applicable and a new solution for the distributed control problems in the field of automation and for the rotary table systems in particular.
Źródło:
Acta Physica Polonica A; 2017, 132, 3; 749-752
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New Exact Solutions for Boussinesq Type Equations by Using (G'/G, 1/G) and (1/G')-Expansion Methods
Autorzy:
Demiray, S.
Ünsal, Ö.
Bekir, A.
Powiązania:
https://bibliotekanauki.pl/articles/1198520.pdf
Data publikacji:
2014-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.30.Jr
02.70.Wz
05.45.Yv
94.05.Fg
Opis:
In this paper, the (G'/G, 1/G) and (1/G')-expansion methods with the aid of Maple are used to obtain new exact traveling wave solutions of the Boussinesq equation and the system of variant Boussinesq equations. The travelling wave solutions are expressed by the hyperbolic functions, the trigonometric functions, and the rational functions. It is shown that the proposed method provides a powerful mathematical tool for solving nonlinear wave equations in mathematical physics and engineering.
Źródło:
Acta Physica Polonica A; 2014, 125, 5; 1093-1098
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performance Analysis of a Diesel Cycle under the Restriction of Maximum Cycle Temperature with Considerations of Heat Loss, Friction, and Variable Specific Heats
Autorzy:
Hou, S.
Lin, J.
Powiązania:
https://bibliotekanauki.pl/articles/1492763.pdf
Data publikacji:
2011-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.70.Ln
82.60.Fa
88.05.-b
Opis:
The objective of this study is to examine the influences of heat loss characterized by a percentage of fuel's energy, friction and variable specific heats of working fluid on the performance of an air standard Diesel cycle with the restriction of maximum cycle temperature. A more realistic and precise relationship between the fuel's chemical energy and the heat leakage that is constituted on a pair of inequalities is derived through the resulting temperature. The variations in power output and thermal efficiency with compression ratio, and the relations between the power output and the thermal efficiency of the cycle are presented. The results show that the power output as well as the efficiency where maximum power output occurs will increase with the increase of maximum cycle temperature. The temperature-dependent specific heats of working fluid have a significant influence on the performance. The power output and the working range of the cycle increase while the efficiency decreases with increasing specific heats of working fluid. The friction loss has a negative effect on the performance. Therefore, the power output and efficiency of the cycle decrease with increasing friction loss. It is noteworthy that the effects of heat loss characterized by a percentage of fuel's energy, friction and variable specific heats of working fluid on the performance of a Diesel-cycle engine are significant and should be considered in practice cycle analysis. The results obtained in the present study are of importance to provide a good guidance for the performance evaluation and improvement of practical Diesel engines.
Źródło:
Acta Physica Polonica A; 2011, 120, 6; 979-986
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On Analysis of DSC Curves for Characterization of Intrinsic Properties of NiTi Shape Memory Alloys
Autorzy:
Ziółkowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/1419019.pdf
Data publikacji:
2012-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.70.Ln
81.30.Kf
81.70.Pg
82.60.Fa
62.20.fg
87.85.J-
Opis:
Differential scanning calorimetry is discussed as a tool for characterization of shape memory alloy materials with the example of $Ni_{51at.%}-Ti$ polycrystalline material. Some inconsistencies connected with the differential scanning calorimetry analysis results present in the contemporary literature are indicated, for example large discrepancies in the registered heats of phase transition or differences in registered heats of forward and reverse phase transition, especially in the case of multi-stage phase transition sequences. An attempt is undertaken to explain some of the discrepancies. The overall conclusion from the present work is that forward and reverse sensible heats of phase transition are equal, and discrepancies reported in the literature are artefacts. It is recommended that as a standard practice of differential scanning calorimetry analysis of shape memory alloy materials not only characteristic temperatures but also sensible heat of phase transition should be reported, which can be done at practically no additional cost.
Źródło:
Acta Physica Polonica A; 2012, 122, 3; 601-605
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical and Ultrasonic Investigations of Phase Transitions in Ferroelectric RbHSeO$\text{}_{4}$ Single Crystal
Autorzy:
Sveleba, S. A.
Bublik, M. I.
Polovinko, I. I.
Kityk, A. V.
Sopronuk, V. P.
Czapla, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1920942.pdf
Data publikacji:
1992-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.70.Kb
77.20.+y
05.70.Fh
Opis:
Birefringence and ultrasonic measurements were done for ferroelectric RbHSeO4 crystal. Influences of both stresses (σ$\text{}_{i}$) and pressure on the properties and phase transition were studied as well. The observed dependence of δ(Δn$\text{}_{b}$) = f(σ$\text{}_{5}$) shows hysteresis loop characteristic of ferroelectric phase whereas the dependence of δ(Δn$\text{}_{c}$) = f(σ$\text{}_{6}$) shows hysteresis loop characteristic of ferroelastic phase. Birefringence measurements prove the phase transition to ferroelectric phase at 373 K. Additionally, the phase transition was found at 398 K. The new phase may be regarded as an incommensurate one. On the grounds of the stresses influence the phase diagram is constructed in coordinates T, σ$\text{}_{5}$. The linear decrease in T$\text{}_{c}$ with increase in pressure is observed in ultrasonic studies and it is similar to the results obtained in DSC measurements.
Źródło:
Acta Physica Polonica A; 1992, 82, 3; 481-486
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic Structure of Zinc-Blende Zn$\text{}_{0.5}$Co$\text{}_{0.5}$Se: Theoretical Study
Autorzy:
Hołda, A.
Markowski, R.
Dębowska, D.
Kisiel, A.
Zimnal-Starnawska, M.
Piacentini, M.
Zema, N.
Lama, F.
Powiązania:
https://bibliotekanauki.pl/articles/1950806.pdf
Data publikacji:
1996-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.-b
71.20.Cf
71.70.-d
Opis:
In this paper we present partial densities of states for spin-polarized antiferromagnetic phase of Zn$\text{}_{0.5}$Co$\text{}_{0.5}$Se as well as schematic layouts of the bands, obtained using the ab initio self-consistent semi-relativistic linear muffin tin orbital method. We also present, from theoretical point of view, the analysis of influence of the transition metal cobalt on the electronic structure of a pure ZnSe.
Źródło:
Acta Physica Polonica A; 1996, 90, 4; 817-820
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic Structure of Zinc-Blende Zn$\text{}_{0.5}$V$\text{}_{0.5}$Se: Theoretical Study
Autorzy:
Markowski, R.
Hołda, A.
Dębowska, D.
Kisiel, A.
Zimnal-Starnawska, M.
Piacentini, M.
Zema, N.
Lama, F.
Powiązania:
https://bibliotekanauki.pl/articles/1934068.pdf
Data publikacji:
1995-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.-b
71.70.-d
71.20.Cf
Opis:
In this paper we present a comprehensive study of electronic structure of Zn$\text{}_{0.5}$V$\text{}_{0.5}$Se from the theoretical point of view. Partial and total density of states for spin-polarized antiferromagnetic phase of Zn$\text{}_{0.5}$V$\text{}_{0.5}$Se as well as schematic layouts of the bands have been obtained using the ab initio self-consistent semirelativistic linear muffin-tin orbital method.
Źródło:
Acta Physica Polonica A; 1995, 88, 5; 1023-1027
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:
Microplasma Noise Stimulated by Microwave Electric Field
Autorzy:
Namajūnas, A.
Tamaševičius, A.
Mykolaitis, G.
Bumelienė, S.
Požela, J.
Powiązania:
https://bibliotekanauki.pl/articles/2041773.pdf
Data publikacji:
2005-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.40.Ca
52.25.Gj
72.70.+m
85.30.-z
Opis:
Si and GaAs avalanche diodes containing microplasmas are investigated. Microwave field applied to the diode in addition to reverse dc bias results in considerable spread of noise spectrum and in the increase of noise power. The microplasma noise spectra cover very high (30 to 300 MHz) and ultrahigh (300 to 1000 MHz) frequency bands, while the effective noise temperature is about 10$\text{}^{8}$ K.
Źródło:
Acta Physica Polonica A; 2005, 107, 2; 369-372
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanism and kinetic parameters of the thermal decomposition of gibbsite Al(OH)₃ by thermogravimetric analysis
Autorzy:
Redaoui, D.
Sahnoune, F.
Heraiz, M.
Raghdi, A.
Powiązania:
https://bibliotekanauki.pl/articles/1057886.pdf
Data publikacji:
2017-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.70.Pg
81.05.Je
81.05.Mh
81.30.Mh
07.85.Nc
Opis:
In this study, the mechanism and the kinetic parameters of the thermal decomposition of gibbsite Al(OH)₃ were studied by differential thermogravimetry technique under non-isothermal conditions, between room temperature and 1200 K at heating rates of 5, 10, 15 and 20°C min¯¹. The obtained differential thermogravimetry curves show clearly three distinct peaks. The first peak is due to the partial dehydroxylation of gibbsite. Among the 32 types of differential equations of non-isothermal kinetics, we have found that the most suitable mechanism is (A_{3/2}: g(x)=[-ln(1-x)]^{2/3}) also called Avrami-Erofeev equation of order 2/3. The values of the activation energy E_{A} and of the pre-exponential factor K are 157 kJ mol¯¹ and 7.58×10¹⁵ s¯¹, respectively. The second peak corresponds to the decomposition of gibbsite to boehmite. Decomposition is controlled by the rate of second-order reaction (F₂: g(x)=(1-x)¯¹-1), under the applied conditions. The activation energy E_{A} and pre-exponential factor K correspond to 243 kJ mol¯¹ and 3.73×10²² s¯¹, respectively. The third peak is due to transformation of boehmite to alumina. However the mechanism for such transformation is better described by the 3/2 rate order reaction (F_{3/2}: g(x)=(1-x)^{-1/2}-1). In addition, the values of E_{A} and K were determined to be around 296 kJ mol¯¹ and 1.82×10¹⁹ s¯¹, respectively. The results of differential thermogravimetry were supplemented by the differential thermal analysis. X-ray powder diffraction analysis was carried out for samples of gibbsite treated at different temperatures between 200 and 1200°C in 200°C steps.
Źródło:
Acta Physica Polonica A; 2017, 131, 3; 562-565
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Porosity of Silica Monoliths with Tailored Mesopores of Ink-Bottle Shape Determined by Nitrogen Adsorption and Positron Annihilation Lifetime Spectroscopy
Autorzy:
Sienkiewicz, A.
Kierys, A.
Gorgol, M.
Zaleski, R.
Powiązania:
https://bibliotekanauki.pl/articles/1033934.pdf
Data publikacji:
2017-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Rm
68.43.-h
81.70.-q
78.70.Bj
36.10.Dr
Opis:
The comparison of pore size distributions obtained with the use of two porosimetric methods: low temperature nitrogen sorption (LN2) and positron annihilation lifetime spectroscopy (PALS), was performed for porous silica monoliths. Four investigated samples were prepared under various synthesis conditions. Nitrogen sorption showed the presence of bottle-shaped pores in all investigated samples. In addition, it seems that the presence of methanol during synthesis influences porosity to a greater extent than organic additives. Quite good agreement between the LN2 and PALS results was observed only for the silica monolith synthesized with β-cyclodextrins as pore directing agent. The biggest discrepancy in the results obtained from these two techniques was observed for the silica gel synthesized with no additives. The origin of such discrepancies, taking into account the shape of pore size distribution and deficiencies of data analysis techniques, is discussed.
Źródło:
Acta Physica Polonica A; 2017, 132, 5; 1568-1571
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Local Real Estate Markets in Poland as a Network of Damped Harmonic Oscillators
Autorzy:
Kulesza, S.
Belej, M.
Powiązania:
https://bibliotekanauki.pl/articles/1388528.pdf
Data publikacji:
2015-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.70.Ln
89.65.Gh
89.75.Da
Opis:
The paper deals with time series of housing prices on local real estate markets in Warszawa (WAW), Kraków (KRK) and Poznań (POZ) from 2006 to 2013 using a model of critically-damped harmonic oscillator to study underlying system dynamics. Performed analysis reveals the presence of housing bubble in 2007 that emerge from otherwise quasi-regular evolution around the equilibrium state. Time series of housing prices are fitted numerically to estimate important parameters of the system, for example: decay constant, delay time, and price equilibrium level, which help us to chose the leading market. Obtained results show reasonable matching of the model with housing prices in WAW and POZ, but less in KRK. The latter data, however, are found to agree well with the model of under-damped harmonic oscillator, which actually suggests that some trembling might occur in that market. Nevertheless, local real estate markets can be thought of as a system of interconnected damped harmonic oscillators with leading market in WAW that is about to change under aggregate macroeconomic fluctuations (exogenous factors) triggering changes in remaining markets.
Źródło:
Acta Physica Polonica A; 2015, 127, 3A; A-99-A-102
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Metastable Magnetic Structures in the Blume-Capel Model
Autorzy:
Kułakowski, K.
Antoniuk, M.
Del Moral, A.
Gawroński, P.
Powiązania:
https://bibliotekanauki.pl/articles/2013716.pdf
Data publikacji:
2000-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.70.Fh
75.10.Hk
75.30.Kz
Opis:
We discuss a first-order phase transition from non-magnetic to magnetic phase at T=0. New results are presented on a spontaneously formed magnetic phase and its energy in the C15 atomic structure, in the presence of the antiferromagnetic interaction. A dynamic phase diagram is constructed for the phase transition. The results are discussed in the context of the pressure-driven phase transition, which was observed experimentally in YMn$\text{}_{2}$.
Źródło:
Acta Physica Polonica A; 2000, 97, 5; 893-896
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of the Local Environment of Mn Ions Implanted in GaSb
Autorzy:
Wolska, A.
Lawniczak-Jablonska, K.
Klepka, M.
Barcz, A.
Hallen, A.
Arvanitis, D.
Powiązania:
https://bibliotekanauki.pl/articles/1538865.pdf
Data publikacji:
2010-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Dm
61.72.U-
61.05.cj
Opis:
The first attempts to establish an implantation process leading to formation of ferromagnetic inclusions inside the GaSb matrix are presented. Gallium antimonide containing ferromagnetic MnSb precipitations is considered as a promising material for novel spintronic applications. It is possible to obtain such inclusions during the molecular beam epitaxy (MBE) growth. However, for commercial application it would be also important to find an optimal way of producing this kind of inclusions by Mn ions implantation. In order to achieve this goal, several parameters of implantation and post annealing procedures were tested. The ion energy was kept at 10 keV or 150 keV and four different ion doses were applied, as well as various annealing conditions. The analysis of X-ray absorption spectra allowed to estimate the local atomic order around Mn atoms. Depending on the implantation energy and annealing processes, the manganese oxides or manganese atoms located in a heavily defected GaSb matrix were observed. The performed analysis helped in indicating the main obstacles in formation of MnSb inclusions inside the GaSb matrix by Mn ion implantation.
Źródło:
Acta Physica Polonica A; 2010, 117, 2; 286-292
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Water Sorption and Dessiccation in a Portland Cement Paste: Positron Annihilation Results
Autorzy:
Consolati, G.
Dotelli, G.
Quasso, F.
Powiązania:
https://bibliotekanauki.pl/articles/2024222.pdf
Data publikacji:
2001
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Bj
71.60.+z
81.05.Rm
Opis:
Positron annihilation experiments were carried out on a Portland cement paste one year aged, which was subjected to cycles of dessiccation and subsequent water resaturation, in order to study possible changes of the porosity. Analysis of the annihilation time spectra suggests that drying and rewetting treatments do not induce irreversible modifications in the configuration of the finest gel pores.
Źródło:
Acta Physica Polonica A; 2001, 99, 3-4; 345-349
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Binary Phase Diagram of Water/Brij58 Studied by SAXS
Autorzy:
Fall, S.
Pattier, B.
Benyayia, L.
Gibaud, A.
Powiązania:
https://bibliotekanauki.pl/articles/1490051.pdf
Data publikacji:
2012-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.30.-t
61.05.C-
64.70.dg
Opis:
The phase diagram of the binary water/Brij58 system has been studied at constant temperature T = 20°C first by simple optical observation and then by small angle X-ray scattering. The small angle X-ray scattering patterns in the isotropic diluted phase are analyzed in a quantitative way by refining the experimental measurements with a model assuming hard spherical micelles in interaction. The micelles are described by a poly dispersed core-shell model and the interaction by the Perkus-Yevick hard-sphere model. The fitted parameters are analyzed in detail to determine the way polyoxyethylene blocks are hydrated with respect to the volumic fraction of water. In the more concentrated regime, the crystalline phases that are identified are the Fm3m cubic, the 2D hexagonal and the lamellar phases. The structural parameters that describe each phases are analyzed and commented. The small angle X-ray scattering study is complemented by the determination of the temperature dependent liquid-solid transition by rheology.
Źródło:
Acta Physica Polonica A; 2012, 121, 2; 388-396
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structure of Dilute Micellar Water Solutions of Nonionic Dimeric Surfactant Study by Small Angle Neutron Scattering Method
Autorzy:
Rajewska, A.
Wilk, K.
Powiązania:
https://bibliotekanauki.pl/articles/1377618.pdf
Data publikacji:
2014-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.05.fg
82.70.-y
Opis:
The new sugar gemini nonionic surfactant - bis(C12LA) $[(C_{56}H_{110}N_{4}O_{22})]$ was investigated by small angle neutron scattering method for six dilute solutions with concentrations: 20 CMC, 50 CMC, 75 CMC, 100 CMC, 125 CMC and 150 CMC (CMC = 7.3×$10^{-6}$ mol/$dm^{3}$, CMC = critical micellar concentration) and three temperatures (20°C, 40°C and 60°C) for the q range 0.003-0.4 $Å^{-1}$. The aim of experiment was to determine the size and shape of micelles as a function of concentration and temperature in heavy water micellar solutions of nonionic dimeric surfactant bis(C12LA).
Źródło:
Acta Physica Polonica A; 2014, 126, 6; 1272-1274
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:
On the Critical Behaviour and Phase Diagram of Ising-like Metamagnet in a Transverse Field
Autorzy:
Lukierska-Walasek, K.
Powiązania:
https://bibliotekanauki.pl/articles/1930584.pdf
Data publikacji:
1994-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Kz
81.30.Dz
05.70.Fh
Opis:
The quantum Ising-like metamagnet in a field Γ perpendicular to the easy direction in the mean field approximation is investigated. The conditions for the existence of critical and tricritical points have been analyzed. The result is illustrated by an appropriate plot in three-dimensional space of the following parameters: the temperature, Γ, and field parallel to the easy direction.
Źródło:
Acta Physica Polonica A; 1994, 85, 2; 381-384
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase Transitions in a Coupled Electron and Spin Model on the Shastry-Sutherland Lattice
Autorzy:
Farkašovský, P.
Čenčariková, H.
Powiązania:
https://bibliotekanauki.pl/articles/1366499.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.10.-b
75.40.Mg
05.70.Fh
Opis:
The thermodynamics of a simple electron-spin model proposed recently for a description of magnetization processes in rare-earth tetraborides is studied numerically by the canonical Monte Carlo method in two-dimensions. The model is based on the coexistence of two subsystems, and namely, the spin subsystem described by the Ising model and the electronic subsystem described by the free-electron model on the Shastry-Sutherland lattice (SSL). Moreover, both subsystems are coupled by the anisotropic spin-dependent interaction of the Ising type. At T=0 the system exhibits the magnetization plateau (MP) at m/$m_s$=1/2, 1/3, 1/5, 1/7, 1/9 and 1/11 of the saturated spin magnetization $m_s$. For the largest phases corresponding to m/$m_s$=0, 1/3 and 1/2 we have examined the nature of the phase transitions from the low-temperature ordered phase (LTOP) to the high-temperature disordered phase (HTDP). It is shown that all phases persist also at finite temperatures (up to the critical temperature $T_c$) and that the phase transition at the critical point is of the second order for the m/$m_s$=0 phase and of the first order for the m/$m_s$=1/3 and 1/2 phases.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 44-45
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prediction of Impact Resistance Properties of Concrete Using Radial Basis Function Networks
Autorzy:
Yazici, S.
Inan Sezer, G.
Sezer, A.
Powiązania:
https://bibliotekanauki.pl/articles/1031254.pdf
Data publikacji:
2017-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.70.Bt
79.20.Ap
07.05.Mh
Opis:
This study presents an investigation of the prediction of impact resistance of steel-fiber-reinforced concrete and ordinary concrete specimens. In the experimental part of this study, parameters identifying impact resistance of various concrete mixtures were determined using an impact test machine, in accordance with ACI Committee 544. For this aim, concrete specimens containing three different aggregates (basalt, limestone and natural aggregate) were cured in water at 20°C for 28 days. After curing impact resistance tests were performed on specimens having compressive strength values between 20 and 50 MPa, to determine the blows to initial crack and failure. The specimens were also subjected to splitting tensile strength and ultrasonic pulse velocity tests. Initially, using blows to initial crack and failure, many attempts were made to classify the impact resistance of different types of concrete in terms of the origin of used aggregate, strength properties or ultrasonic pulse velocity, however, this made no sense. The specimens could only be classified in terms of steel fiber presence. Therefore, radial basis function network, which belongs to another kind of unsupervised classifier network, was used to estimate the two above-mentioned impact resistance parameters. In this scope, independent from aggregate origin used in preparation of specimens, compressive strength, splitting tensile strength and ultrasonic pulse velocity of the specimens were used to predict the impact resistance parameters of the concrete specimens. The results revealed that three listed parameters can be used for estimation of blows to formation of initial crack and failure. Scatter plots, root mean square error and absolute value of average residual parameters were used to verify the errors in predictions, which were very low, compared with the uncertainty in test and ambiguity of data in hand.
Źródło:
Acta Physica Polonica A; 2017, 132, 3; 1036-1040
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Outdoor Ageing of an Ethylene-Propylene Copolymer: A Positron Annihilation Study
Autorzy:
Consolati, G.
Quasso, F.
Gallo, R.
Severini, F.
Powiązania:
https://bibliotekanauki.pl/articles/2043322.pdf
Data publikacji:
2005-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.41.+e
78.70.Bj
81.05.Lg
Opis:
An investigation on the environmental degradation of an ethylene-propylene copolymer was carried out through positron annihilation lifetime spectroscopy, density and differential scanning calorimetry measurements. Polymer sheets were exposed to sunlight up to 11000 hours. Density and melting enthalpy increase with ageing, while ortho-positronium intensity decreases; ortho-positronium lifetime does not show significant variations up to 4400 hours. At higher exposures it starts to decrease. Outdoor ageing produces an increased crystallinity of the copolymer; also a degradation occurs with formation of carbonyl groups. The corresponding Ps inhibition is the main reason for the decrease in ortho-positronium intensity, the other one being the reduced amount of the amorphous phase available. The lifetime decrease observed at the highest exposures can be interpreted in terms of a shrinking of the nanoholes trapping positronium.
Źródło:
Acta Physica Polonica A; 2005, 107, 5; 805-810
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the Possibility to Control an Atom Motion in a FCC Iron Nanocluster
Autorzy:
Bondarenko, N.
Nedolya, A.
Powiązania:
https://bibliotekanauki.pl/articles/1030620.pdf
Data publikacji:
2018-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.70.Ns
07.05.Pt
36.40.-c
61.46.Hk
61.46.Bc
Opis:
The energy of the isolated iron nanocluster was calculated by molecular mechanics method using the Lennard-Jones potential depending on the position of impurity carbon atom and substitutional atoms of nickel. The cluster included a carbon atom, that drifted from an inside octahedral interstice to a direction ⟨022⟩ to the surface directly or to a tetrahedral interstice in ⟨1̅11⟩ direction and after that in ⟨222⟩ direction to the surface. In addition one of 14 iron atoms was replaced by a nickel atom (or pair atoms), the position of which was changing during simulation. It is shown that there were positions of a nickel atom that significantly affected nanoclusters energy. The calculation results indicated that position of a carbon atom in the octahedral interstice was more energetically favorable than tetrahedral interstice in the case of fcc nanocluster. On the other side, the potential barrier was smaller in the direction ⟨1̅11⟩ than in the direction ⟨022⟩. This indicates that there are two ways for carbon atom to drift to the surface of the nanocluster. The positions of nickel atoms were identified, which significantly affected the height of potential barriers of a tetrahedral and an octahedral interstice and determined the possible direction of carbon atoms drift. This allows manipulating atoms at the surface of nanocluster.
Źródło:
Acta Physica Polonica A; 2018, 133, 2; 277-279
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:
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:
A Study of Generalized Thermoelastic Interaction in an Infinite Fibre-Reinforced Anisotropic Plate Containing a Circular Hole
Autorzy:
Abbas, Ibrahim
Abd-alla, Abo-el-nour
Powiązania:
https://bibliotekanauki.pl/articles/1505045.pdf
Data publikacji:
2011-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
46.25.Hf
81.05.Ni
02.70.Dh
Opis:
In the context of Lord and Shulman theory, the generalized thermoelastic theory with thermal relaxation is used to investigate the thermoelastic interaction in an infinite fibre-reinforced anisotropic plate containing a circular hole. Thermoelastic interactions are caused by a uniform step at temperature applied to the boundary of the hole which is stress-free. The problem is solved numerically using a finite element method and the numerical solutions of the non-dimensional governing partial differential equations of the problem are shown graphically. The effects of the presence and absence reinforcement on temperature, stress and displacement are studied.
Źródło:
Acta Physica Polonica A; 2011, 119, 6; 814-818
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of Feederless Casting Limits by Thermal Analysis in Cast Iron
Autorzy:
Erturk, S.
Kumruoglu, L.
Ozel, A.
Powiązania:
https://bibliotekanauki.pl/articles/1030308.pdf
Data publikacji:
2017-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Bx
81.30.-t
81.30.Fb
81.70.Pg
Opis:
In this study the determinations of melt quality was carried out by thermal analysis of ductile iron. The aim of the study was to determine the limits of feederless casting after the determination of inoculation quality in cast iron. Production method of pouring into a sand mold in the entirety and without using feeder systems has been investigated. Forms of the solidification and volume change have been investigated with simulation program as functions of inoculation quality, type of resin in the mold and mold rigidity. Results of the analysis have been compared with the results of experimental iron casting.
Źródło:
Acta Physica Polonica A; 2017, 131, 3; 370-373
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structure and magnetic properties of Fe-B-Si-Zr metallic glasses
Autorzy:
Babilas, R.
Radoń, A.
Gębara, P.
Powiązania:
https://bibliotekanauki.pl/articles/1054824.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
33.45.+x
61.05.cp
64.70.pe
75.50.Kj
Opis:
Fe-based amorphous alloys were characterized by X-ray diffraction, transmission Mössbauer spectroscopy and vibrating sample magnetometry. The studies were performed on (Fe_{0.75}B_{0.15}Si_{0.1})_{100-x}Zr_{x} (x=0, 1, 3) metallic glasses in the form of ribbons. The glassy samples were prepared by the "melt spinning" technique in argon protective atmosphere. The XRD patterns show the broad diffraction halo that is typical for amorphous Fe-based alloys. The Mössbauer spectroscopy allows to study the local environments of the Fe atoms in the glassy state, showing the changes in the amorphous structure due to the changing of Zr addition. From hysteresis loops obtained from vibrating sample magnetometry measurements, coercive force and saturation magnetization were determined versus different Zr content. The obtained magnetic properties allow to classify the studied amorphous alloys in as-cast state as soft magnetic materials.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 726-728
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Research on Nitinol Alloy Material Fatigue Behavior Analysis of Cardiovascular Stent in Medical Engineering
Autorzy:
Karaçalı, Ö.
Powiązania:
https://bibliotekanauki.pl/articles/1194117.pdf
Data publikacji:
2015-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.40.Np
81.70.Bt
81.05.Bx
87.10.Kn
Opis:
Biocompatible cardiovascular stents are small cylindrical support structures introduced into the stenosed arteries to reopen the lumen and to restore blood flow in treating heart disease, which have revolutionized interventional cardiology. Cardiovascular stent designers are confronted with two basic requirements, such as an "infinite" life and the "thinnest" wires. Pulsatile pressure, repetitive mechanical forces, within the coronary artery may result in stent fatigue and fracture after stent implantation, particularly in patients with complex coronary disease. This research describes the simulation analysis of cardiovascular stents, to provide designers with estimates of their in vivo structural behavior and fatigue properties. Stent material failure or device fatigue remains major concern for stent manufactures and researchers. The objective of this research was to simulate the mechanical behavior of the stent using finite element method. A finite element analysis (FEA) of cardiovascular stent under fatigue cyclic loading conditions is presented. Commercial software was employed to study the fatigue performance of nitinol alloy materials in new stent systems. The effects of deployment, and static cyclic pressure loading on cardiovascular stent fatigue life were simulated and analyzed for nitinol alloy material. The investigation results displayed a significant correlation between material combinations, stent loading, and fatigue behavior.
Źródło:
Acta Physica Polonica A; 2015, 127, 4; 1167-1169
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hot Compression Test of Heat Resistant Steel
Autorzy:
Fedoriková, A.
Kvačkaj, T.
Kočiško, R.
Bidulský, R.
Petroušek, P.
Powiązania:
https://bibliotekanauki.pl/articles/1032933.pdf
Data publikacji:
2017-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Bx
81.40.Gh
81.40.Np
02.70.Dh
Opis:
This article deals with the analysis of formability of heat resistant steel type 9Cr-1Mo by physical laboratory simulation - hot compression test. The 9Cr-1Mo steel belongs to modern 9%Cr tempered martensitic steel for high-temperature applications in advanced thermal power plants. The shape of the sample was defined based on numerical simulations. The laboratory simulation of forming process called physical simulation - specifically hot compression test was realized in the temperature range from 500 to 950°C and total deformation in the range from 39 to 52%. Cracks formed during hot compression test in the notches are assessed. Subsequently, the relation between the compression temperature, strain, and crack length was defined. The suitable workability corresponds to the temperature range 650-900°C, it agrees with results of numerical simulations. At a temperature of 900°C there is marginal relative deformation without rupture ε =39.9%, which corresponds to the value according to simulations NCL criteria 0.501.
Źródło:
Acta Physica Polonica A; 2017, 131, 5; 1340-1343
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimization of the inter-operation annealing of cold-drawn eutectoid steels
Autorzy:
Grygier, D.
Rutkowska-Gorczyca, M.
Żak, A.
Jasiński, R.
Powiązania:
https://bibliotekanauki.pl/articles/1075902.pdf
Data publikacji:
2016-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Bx
81.40.Ef
81.70.Bt
Opis:
The test of the results presented in this paper has demonstrated that the most suitable recrystallizing annealing temperature for cold drawn eutectoid steels is 700°C. The microscopic examinations, with the use of scanning electron microscopy and transmission electron microscopy and the results of mechanical properties tests have shown that only at this temperature it is possible to obtain the fully recrystallized homogeneous fine-grained structure of the pearlitic steel.
Źródło:
Acta Physica Polonica A; 2016, 130, 4; 931-934
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nanocrystallisation of Soft Magnetic Fe-Co-Zr-Cu-B Alloys
Autorzy:
Wlazłowska, A.
Ferenc, J.
Latuch, J.
Kulik, T.
Powiązania:
https://bibliotekanauki.pl/articles/2035520.pdf
Data publikacji:
2002-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.43.Dq
75.50.Bb
75.50.Kj
75.60.Ej
81.05.Kf
81.10.Jt
81.70.Ex
81.70.Pg
Opis:
In the present study, Fe$\text{}_{41}$Co$\text{}_{41}$B$\text{}_{10}$Zr$\text{}_{7}$Cu$\text{}_{1}$ alloy has been investigated in order to evaluate its thermal stability and structure after heat treatment, as well as the impact of heat treatment on magnetic properties. X-ray diffractometry, differential scanning calorimetry, chemical composition microanalysis, transmission electron microscopy, and magnetic hysteresis loop measurement techniques were employed. The crystallisation temperature of the as-quenched alloy is 490ºC (continuous heating at 5ºC/min). The melt-spun ribbon having 27μm in thickness was annealed for 1 hour at temperatures from 400 to 700ºC. The alloy after treatment at about 550ºC underwent primary crystallisation, with the average size of crystals under 20 nm. This specimen shows the coercive field of 38 A/m, as compared to about 160 A/m reported for a similar alloy (Fe$\text{}_{44}$Co$\text{}_{44}$B$\text{}_{4}$Zr$\text{}_{7}$Cu$\text{}_{1}$) with a similar structure, annealed at 600ºC.
Źródło:
Acta Physica Polonica A; 2002, 102, 2; 323-328
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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