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Wyszukujesz frazę "05.30.-d" wg kryterium: Wszystkie pola


Tytuł:
Nonequilibrium Reduced-Density Operator for Nanoscopic Systems
Autorzy:
Jacyna-Onyszkiewicz, Z.
Powiązania:
https://bibliotekanauki.pl/articles/2035619.pdf
Data publikacji:
2002-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.30.-d
05.70.Ln
Opis:
Retarded forms of the nonequilibrium reduced-density operator are derived from the generalized Schrödinger variational principle of a system with both mechanical and thermal perturbations, taking into account the additional condition that the values of generalized thermodynamic coordinates are fixed at infinitely remote past. This reduced density operator may be useful in describing nonequilibrium properties of nanoscopic and mesoscopic systems, as well as ultrathin films. With the help of this reduced-density operator the generalized Green-Kubo formulae are obtained.
Źródło:
Acta Physica Polonica A; 2002, 102, 6; 717-727
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Generalised Equilibrium Reduced-Density Operator
Autorzy:
Jacyna-Onyszkiewicz, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1030814.pdf
Data publikacji:
2018-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
03.65.Ca
05.30.-d
Opis:
Equilibrium reduced-density operators for subsystems of the universe are derived from the generalised Schrödinger variational principle, additionally assuming that the values of von Neumann entropy for the subsystems are fixed and higher than zero. The obtained reduced-density operator may be useful for description of the properties of an arbitrary system (macroscopic, mesoscopic, nanoscopic, or microscopic) in the equilibrium mixed state.
Źródło:
Acta Physica Polonica A; 2018, 133, 5; 1231-1240
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of the Mathematical Methods of the Braid Group Theory to Quantization of Many-Particle Systems
Autorzy:
Jacak, D.
Jacak, L.
Wieczorek, K.
Powiązania:
https://bibliotekanauki.pl/articles/1930615.pdf
Data publikacji:
1994-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
03.65.Bz
05.30.-d
Opis:
The problem of the non-standard statistics for one-, two- and three-dimensional systems of N identical particles on various manifolds is reviewed in terms of the braid group theory. The braid groups together with their unitary representations are studied for the line, circle, plane, sphere, torus and the three-dimensional Euclidean space. Nonequivalent quantizations of several physical systems are presented.
Źródło:
Acta Physica Polonica A; 1994, 85, 3; 483-496
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fractional Statistics in Low-Dimensional Systems - Random-Phase Approximation for Anyons at Finite Temperatures
Autorzy:
Jacak, L.
Sitko, P.
Powiązania:
https://bibliotekanauki.pl/articles/1929138.pdf
Data publikacji:
1993-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.30.-d
74.20.Kk
Opis:
The non-zero temperature theory for non-interacting anyon gas is developed within the random-phase approximation. It is proved that the phase transition superconducting normal state of anyons does not occur and the Meissner effect disappears at non-zero temperatures. The mutual correspondence of new Haldane theory of anyons and mean field treatment is found. A short overview of the fractional statistics theory is also given.
Źródło:
Acta Physica Polonica A; 1993, 83, 4; 399-416
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Time Evolution of the Magnetic Chains with Uniaxial Anisotropy
Autorzy:
Woźniak, D.
Drzewiński, A.
Kamieniarz, G.
Powiązania:
https://bibliotekanauki.pl/articles/1385537.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.10.Jm
76.60.Es
05.30.-d
Opis:
In the framework of the matrix product states representation the effect of the single-ion anisotropy on the time evolution of the initial state after a sudden quench of the local magnetic field has been investigated. The overlap of the initial and time-evolved states, so called the Loschmidt echo, magnetization profiles and correlation functions are presented.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 333-335
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamics of Users Activity on Web-Blogs
Autorzy:
Kozioł, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1398897.pdf
Data publikacji:
2016-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
89.65.-s
89.20.Hh
05.30.-d
Opis:
Activity of users on Internet discussion forums is analyzed. The rank of users is shown to be approximated better by stretched-exponential function than by the Zipf law. Cumulative distribution function is found as an excellent tool in analysis of the dynamics of the collective social phenomena. We are able to approximate the number of blog comments with time by simple sigmoidal functions: probability of posting a comment is given by P(t)=P₀(t)/[1+P₀(t)], where $P_0(t)=(t//t_0)^{β}$ and β is close to 1.
Źródło:
Acta Physica Polonica A; 2016, 129, 5; 1060-1063
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of Coulomb Interactions Between Fermions on Superconductivity in Boson-Fermion Model
Autorzy:
Kostyrko, T.
Powiązania:
https://bibliotekanauki.pl/articles/1955831.pdf
Data publikacji:
1997-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
67.40.Db
74.20.-z
05.30.-d
Opis:
Influence of Coulomb repulsion between fermions on stability of the superconducting state in the model of boson-like local electron pairs hybridized with wide-band fermions is studied. It is shown rigorously that the Bose condensation of the local pairs implies a divergence of the pairing susceptibility in the fermion subsystem. Charge carrier concentration dependence of the critical temperature T$\text{}_{c}$ is evaluated with the help of random phase approximation and spectral properties of the bosons at T$\text{}_{c}$ are analyzed.
Źródło:
Acta Physica Polonica A; 1997, 91, 2; 399-403
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Relaxation dynamics in the spin-1 Heisenberg antiferromagnetic chain after a quantum quench of the uniaxial anisotropy
Autorzy:
Woźniak, D.
Drzewiński, A.
Kamieniarz, G.
Powiązania:
https://bibliotekanauki.pl/articles/1058535.pdf
Data publikacji:
2016-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.10.Jm
76.60.Es
05.30.-d
75.30.Gw
Opis:
In the framework of the matrix product state representation the effect of a sudden turning on of the uniaxial anisotropy on the time evolution of the Haldane state has been investigated. Depending on the value of the uniaxial anisotropy parameter, the calculations were derived within (or outside) the region where the Haldane gap survives. An exact expression for the time evolution of the Loschmidt echo has been derived and, moreover, its collapse and revival behaviour was captured. In addition, the non-local order parameter of a time evolving state was tracked, revealing two types of relaxations.
Źródło:
Acta Physica Polonica A; 2016, 130, 6; 1395-1400
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Asymmetry Induced Localization
Autorzy:
Kohler, H.
Powiązania:
https://bibliotekanauki.pl/articles/1399044.pdf
Data publikacji:
2013-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.30.-d
03.65.Yz
05.45.Mt
73.23.-b
Opis:
We consider a two-level system, which couples via non-commuting operators to two independent oscillator baths. When the coupling is symmetric, the renormalized hopping matrix element is finite even for infinitely strong coupling strength. The two-level system is in a delocalized phase. For finite coupling strength a localization transition occurs for a critical asymmetry angle, which separates the localized from the delocalized phase. Using the method of flow equations we are able to monitor real time dynamics.
Źródło:
Acta Physica Polonica A; 2013, 124, 6; 1053-1059
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fidelity Decay in Chaotical and Random Systems
Autorzy:
Kohler, H.
Powiązania:
https://bibliotekanauki.pl/articles/1492437.pdf
Data publikacji:
2011-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.30.-d
03.65.Yz
05.45.Mt
73.23.-b
Opis:
Fidelity is the overlap of wave functions with the same initial state propagated in time by slightly different Hamiltonians. Its behavior depends crucially on the choice of the initial wave function state. We review two cases: first, the initial state is random. In this case a simple analytic relation with parametric spectral correlations can be established. The latter quantity is completely determined by the spectral data and can therefore be measured, without knowledge about the wave function. Second, the initial state is an eigenstate of the unperturbed system. In this case fidelity is identical to the survival probability. We find unexpected features like revival and non-ergodicity. In this case fluctuations around the mean are large and the full fidelity distribution becomes a non-trivial function. The full fidelity distribution can be calculated in the long time limit and for small perturbations.
Źródło:
Acta Physica Polonica A; 2011, 120, 6A; A-119-A-126
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Hilbert Space and the Exact Solution of the Spin-Electron Double-Tetrahedral Chain
Autorzy:
Jakubczyk, D.
Gálisová, L.
Powiązania:
https://bibliotekanauki.pl/articles/1402563.pdf
Data publikacji:
2015-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.20.-a
05.30.-d
75.10.Pq
05.50.+q
Opis:
We discuss an exactly solvable double-tetrahedral chain, in which the localized Ising spins regularly alternate with triangular clusters - each available for one mobile electron. We give an exact solution for the considered hybrid system by the construction of the N-th tensor power of the Fourier transformation and using the generalized decoration-iteration mapping tranformation.
Źródło:
Acta Physica Polonica A; 2015, 128, 2; 173-175
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Harmonically Trapped Bosons on the Sierpiński Carpet
Autorzy:
Rovenchak, A.
Powiązania:
https://bibliotekanauki.pl/articles/1535594.pdf
Data publikacji:
2010-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.30.Jp
67.85.-d
64.60.an
Opis:
An ideal Bose-gas confined in a harmonic potential is studied. The thermodynamic properties of the said system are obtained in a general case of D dimensions, where D can be fractional (this corresponds to, e.g., porous medium). For the critical temperature, expansions with respect to the number of particles in the system are obtained. Numerical study is made for D = ln8/ln3 corresponding to the dimensionality of the so-called Sierpiński carpet.
Źródło:
Acta Physica Polonica A; 2010, 118, 4; 531-533
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Self-Similar Solidification of Binary Alloys
Autorzy:
Alexandrov, D.
Ivanov, A.
Malygin, A.
Powiązania:
https://bibliotekanauki.pl/articles/1808056.pdf
Data publikacji:
2009-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
44.05.+e
81.30.Fb
Opis:
The self-similar crystallization process of a binary mixture from a cooled boundary is studied on the basis of two models with a planar front and mushy layer. Approximate analytical solutions of the process describing the solidification with a mushy layer are found. The theory under consideration is in good agreement with experiments carried out by Huppert and Worster for ice growing from aqueous salt solutions.
Źródło:
Acta Physica Polonica A; 2009, 115, 4; 795-799
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Molding Condition on Waviness Profile of GFRP Composites in Compression Molding
Autorzy:
Kim, J.
Kim, H.
Lee, D.
Powiązania:
https://bibliotekanauki.pl/articles/1399878.pdf
Data publikacji:
2013-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Lg
81.05.Qk
88.30.mj
Opis:
During compression molding of glass fiber reinforced plastic composites, annealing and quenching experiment is conducted by changing pre-heating and cooling method. As results, major cause of unevenness that affects waviness profile (winding) is the shrinkage of matrix during holding and cooling process. Waviness profile of the surface on molding in glass fiber reinforced plastic composites will be lower when holding pressure load is higher, mold temperature is lower during demolding, and cooling rate is slower. In addition, surface roughness of moldings is depending on holding pressure load compared with mold temperature. According to molding condition of glass fiber reinforced plastic composites, waviness profile of surface can be quantitatively estimated using the proposed equation.
Źródło:
Acta Physica Polonica A; 2013, 123, 2; 337-340
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pseudospin Models of Superconductors with Very Short Coherence Length
Autorzy:
Robaszkiewicz, S.
Powiązania:
https://bibliotekanauki.pl/articles/1860991.pdf
Data publikacji:
1994-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.20.-z
05.30.Jp
71.28.+d
Opis:
We discuss a few models developed for description of superconductivity with very short coherence length and point out their formal equivalence to specific spin models, such as an anisotropic Heisenberg model (s = 1/2) with two- and four-spin exchange coupling and with fixed magnetization in the z-direction, an XY-Z model with single ion anisotropy and a Kondo-lattice model with anisotropic on-site exchange. New results concerning the phase diagram of the Hubbard model with strong attraction, the electromagnetic properties of systems with the first order superconducting transition and a possibility of local charge moment compensation in systems of coexisting bound pairs and itinerant electrons are presented.
Źródło:
Acta Physica Polonica A; 1994, 85, 1; 117-131
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of Graphics Processing Unit for In-Line Electron Holography
Autorzy:
Morawiec, K.
Dłużewski, P.
Kret, S.
Szczepańska, A.
Li, T.
Sloan, J.
Powiązania:
https://bibliotekanauki.pl/articles/1033020.pdf
Data publikacji:
2017-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.37.Lp
68.37.Og
68.55.Nq
42.30.Rx
61.05.jp
07.05.Pj
42.30.-d
42.30.Wb
Opis:
In the present work, software for exit electron wave reconstruction based on the iterative approach was implemented and a new method for drift-correction of the focal series was proposed.
Źródło:
Acta Physica Polonica A; 2017, 131, 5; 1353-1356
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:
Imaging Properties of Laser-Produced Parabolic Profile Microlenses
Autorzy:
Vasiljević, D.
Murić, B.
Pantelić, D.
Panić, B.
Powiązania:
https://bibliotekanauki.pl/articles/2047865.pdf
Data publikacji:
2007-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.70.Gi
81.05.Zx
42.30.Lr
42.15.Fr
Opis:
Imaging properties of the concave microlens are presented. Microlenses are produced by using tot'hema eosin sensitized gelatin and 532 nm laser irradiation (2nd Nd:YAG harmonic). Imaging properties of microlenses are analized by calculation: the RMS wave front aberration, the diffraction point spread function cross section and the spot diagram. The obtained microlenses had excellent, near diffraction limited, performance for the moderate field angles.
Źródło:
Acta Physica Polonica A; 2007, 112, 5; 993-999
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quantum Bright Soliton in a Disorder Potential
Autorzy:
Sacha, K.
Delande, D.
Zakrzewski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1585122.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
03.75.Lm
72.15.Rn
05.30.Jp
Opis:
At very low temperature, a quasi-one-dimensional ensemble of atoms with attractive interactions tend to form a bright soliton. When exposed to a sufficiently weak external potential, the shape of the soliton is not modified, but its external motion is affected. We develop in detail the Bogoliubov approach for the problem, treating, in a non-perturbative way, the motion of the center of mass of the soliton. Quantization of this motion allows us to discuss its long time properties. In particular, in the presence of a disordered potential, the quantum motion of the center of mass of a bright soliton may exhibit Anderson localization, on a localization length which may be much larger than the soliton size and could be observed experimentally.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 772-778
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analytical Solution for a Problem of Directional Solidification in a Ternary System
Autorzy:
Alexandrov, D.
Ivanov, A.
Powiązania:
https://bibliotekanauki.pl/articles/1808053.pdf
Data publikacji:
2009-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
44.05.+e
81.30.Fb
Opis:
This paper is devoted to new analytic results relating to the nonstationary dynamics of directional solidification of ternary solutions with two moving layers of the phase transition lying between solid and liquid phases. Explicit analytical solutions of the problem under consideration are constructed on the basis of laboratory experiments carried out by Aitta, Huppert and Worster.
Źródło:
Acta Physica Polonica A; 2009, 115, 4; 786-790
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characterization of n-ZnO/p-GaN Heterojunction for Optoelectronic Applications
Autorzy:
Wachnicki, L.
Gieraltowska, S.
Witkowski, B.
Figge, S.
Hommel, D.
Guziewicz, E.
Godlewski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1399138.pdf
Data publikacji:
2013-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
85.30.Kk
61.05.cp
81.05.Dz
Opis:
An important feature of zinc oxide and gallium nitride materials are their similar physical properties. This allows to use them as a p-n junction materials for applications in optoelectronics. In earlier work we presented use of ZnO as a transparent contact to GaN, which may improve external efficiency of LED devices. In this work we discuss properties of a n-ZnO/p-GaN heterostructure and discuss its optimization. The heterostructure is investigated by us for possible applications, e.g. in a new generation of UV LEDs or UV light detectors.
Źródło:
Acta Physica Polonica A; 2013, 124, 5; 869-872
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of the Temperature Dependent Thermal Expansion Coefficients of Bulk AlN by HRXRD
Autorzy:
Kröncke, H.
Figge, S.
Hommel, D.
Epelbaum, B.
Powiązania:
https://bibliotekanauki.pl/articles/1811948.pdf
Data publikacji:
2008-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
01.30.Cc
61.05.cp
81.05.Ea
65.40.De
Opis:
We measured the lattice constants of bulk aluminum nitride crystals at various temperatures by high resolution X-ray diffraction. By the use of a high temperature chamber and a X-ray cryostat a temperature regime from 20 to 1210 K was available. Furthermore, the measured data were fitted by Einstein- and Debye models which yield reliable parameters for the calculation of the thermal expansion coefficients of AlN.
Źródło:
Acta Physica Polonica A; 2008, 114, 5; 1193-1200
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Characterization of Defects in Multi-Layered Composite Materials by Thermal Tomography Methods
Autorzy:
Swiderski, W.
Powiązania:
https://bibliotekanauki.pl/articles/1808057.pdf
Data publikacji:
2009-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.57.-c
07.05.Pj
42.30.-d
42.30.Wb
42.72.Ai
Opis:
The idea of thermal tomography is slicing a work piece for some in-depth layers which exhibit the distribution of thermal properties in materials by the analogy with X-ray tomography. Thermal tomography is based on the analysis of the surface temperature evolution which follows thermal stimulation of test samples. In this paper, some experimental results of applying the dynamic thermal tomography algorithm to a carbon fibre reinforced plastic sample are presented. The efficiency of few data processing methods is discussed.
Źródło:
Acta Physica Polonica A; 2009, 115, 4; 800-804
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Improved Method of Linear Travel-Time Interpolation Ray Tracing Algorithm
Autorzy:
Hao-Quan, W.
Powiązania:
https://bibliotekanauki.pl/articles/1535590.pdf
Data publikacji:
2010-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.05.Pj
42.30.Wb
43.60.+d
Opis:
The linear travel-time interpolation algorithm is improved by the method of ray tracing based on finite difference scheme of eikonal equation. It can simulate the more complex medium. Using the algorithm to calculate travel-time and paths of tracing rays, it is more rapid and accurate than the other conventional methods. The linear travel-time interpolation ray tracing algorithm has a drawback: rays cannot go round the low velocity area if the launching point, the receiving point and the low velocity area distribute on the same column (row). Aiming at the drawback, an improved algorithm is proposed on the basis of researching reconstruction theories. The given algorithm adopts a cross-scanning strategy to carry out forward processing and uses discrete points as the secondary sources to simplify backward processing. The numerical simulation experiments show that the rays can go round the low velocity areas located in the same column (row) of the launching points and the receiving points. Rays scan over the global region only once.
Źródło:
Acta Physica Polonica A; 2010, 118, 4; 521-526
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal Decomposition Kinetics of Algerian Tamazarte Kaolin by Differential Thermal Analysis (DTA)
Autorzy:
Sahnoune, F.
Heraiz, M.
Belhouchet, H.
Saheb, N.
Redaoui, D.
Powiązania:
https://bibliotekanauki.pl/articles/1033455.pdf
Data publikacji:
2017-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
82.30.Lp
81.05.Je
81.05.Mh
81.70.Pg
Opis:
In the present study, the kinetics of meta-kaolinite (Al₂O₃·2SiO₂) formation from Algerian Tamazarte kaolin was investigated by using differential thermal analysis. The differential thermal analysis and the thermogravimetric experiments were carried out on samples between room temperature and 1400°C, at heating rates from 10 to 40°C min¯¹. X-ray diffraction was used to identify the phases present in the samples. The activation energies measured by differential thermal analysis from isothermal and non-isothermal treatments using Johnson-Mehl-Avrami methods with Ligero approximation and using Kissinger-Akahira-Sunose methods were around 145 and 159 kJ/mol, respectively. The Avrami parameter n which indicates the growth morphology parameters were found to be almost equal to 1.60, using non-isothermal treatments, and equal to 1.47 using isothermal treatments. The numerical factor which depends on the dimensionality of crystal growth was 1.60 obtained using Matusita et al. equation. The frequency factor calculated using the isothermal treatment is equal to 1.173× 10⁷ s¯¹. Analysis of the results have shown that bulk nucleation was dominant during kaolinite transformation, followed by three-dimensional growth of meta-kaolinite with polyhedron-like morphology, controlled by diffusion from a constant number of nuclei.
Źródło:
Acta Physica Polonica A; 2017, 131, 3; 382-385
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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