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Wyszukujesz frazę "Wojcik, J." wg kryterium: Wszystkie pola


Tytuł:
Phase Structure in Fe-Cr-Co Permanent Magnet Alloy
Autorzy:
Olszewski, J.
Szymura, S.
Wójcik, J.
Wysłocki, B.
Powiązania:
https://bibliotekanauki.pl/articles/1861167.pdf
Data publikacji:
1994-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.60.Gm
75.60.Ej
Opis:
The Mössbauer spectroscopy, electron microscopy and magnetization measurements were used in order to describe structural changes in Fe$\text{}_{58.75}$Cr$\text{}_{29.4}$Co$\text{}_{11.85}$ alloy during magnetic hardening. Multiphase structure was found in alloy with best magnetic properties.
Źródło:
Acta Physica Polonica A; 1994, 85, 1; 205-208
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Coupling in Core-Ring Photonic Crystal Fibers
Autorzy:
Palka, N.
Ciurapiński, W.
Wojcik, J.
Szustakowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1811539.pdf
Data publikacji:
2008-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.81.Bm
42.81.Cn
42.81.Dp
Opis:
Experimental investigations of light coupling from a core into a ring caused by microbendings in photonic crystal fibres are shown. We present a setup arrangement, mode fields with and without coupling and a plot of power transfer versus localisation of the modulator along the fibre. We also show the most probable explanation of the obtained data.
Źródło:
Acta Physica Polonica A; 2008, 114, 6A; A-157-A-161
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ultrasonic Non-Invasive Method for Relative Changes Measurements of Intima-Media Thickness in Artery Walls
Autorzy:
Trawiński, Z.
Wójcik, J.
Powałowski, T.
Gutkiewicz, P.
Powiązania:
https://bibliotekanauki.pl/articles/1811556.pdf
Data publikacji:
2008-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.25.Ed
43.25.Zx
43.35.Yb
43.35.Bf
43.38.Fx
43.58.Ta
43.60.Tj
Opis:
The aim of this paper is to present the new method for relative changes measurements of intima-media thickness in the common carotid artery wall. The numerical solver was created for calculation of the fields of ultrasonic beams and scattered fields under different boundary conditions and different angles of penetration of ultrasonic beams with respect to the position of the arterial wall. The cylindrical model of the artery was changing the radius and thickness of the wall under cyclic variation of blood pressure. The presented method was verified on a pipe made of latex. The paper describes also the initial results of examinations of the intima-media thickness. The good agreement for the angle dependence and the perpendicular ultrasonic beam displacement from the longitudinal axis of the artery segment between the numerical calculation and experimental results was obtained for different artery diameters.
Źródło:
Acta Physica Polonica A; 2008, 114, 6A; A-243-A-247
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Anisotropy of UFe$\text{}_{10-x}$Ni$\text{}_{x}$Si$\text{}_{2}$ Intermetallic Alloys
Autorzy:
Drzazga, Z.
Suski, W.
Wochowski, K.
Wójcik, J.
Winiarska, A.
Powiązania:
https://bibliotekanauki.pl/articles/2014420.pdf
Data publikacji:
2000-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Gw
75.20.En
61.10.Nz
Opis:
The magnetic anisotropy in UF$\text{}_{10-x}$Ni$\text{}_{x}$Si$\text{}_{2}$ series has been studied by torsion magnetometry and initial ac magnetic susceptibility measurements in the temperature range of 77-293K. The effective anisotropy constant changes with Ni content showing some increase for intermediate concentration. An increase in magnetic anisotropy energy at low temperatures is due to the uranium sublattice ordering. Magnetic anisotropy behaviour in UFe$\text{}_{2}$Ni$\text{}_{8}$Si$\text{}_{2}$ is influenced by an additional enhancement of the 3d sublattice connected with the ordering Fe magnetic moments.
Źródło:
Acta Physica Polonica A; 2000, 98, 5; 555-559
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Propagation Effects in Photonic Liquid Crystal Fibers with a Complex Structure
Autorzy:
Tefelska, M.
Chychłowski, M.
Woliński, T.
Dąbrowski, R.
Rejmer, W.
Wójcik, J.
Powiązania:
https://bibliotekanauki.pl/articles/1506868.pdf
Data publikacji:
2010-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.81.Gs
78.20.Bh
42.79.Kr
Opis:
Chiral nematic liquid crystals are very interesting materials to infiltrate photonic crystal fibers since they are characterized by unique optical properties such as selective Bragg reflection, circular dichroism, and optical activity. In this paper the latest experimental results of the photonic crystal fibers filled with new chiral nematic liquid crystals are presented. Spectral properties of the light propagating in the photonic liquid crystal fibers have been measured and analyzed.
Źródło:
Acta Physica Polonica A; 2010, 118, 6; 1259-1261
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of the Non-Square InGaAsP/InP Quantum Wells in the Electric Field by Photoreflectance
Autorzy:
Kudrawiec, R.
Sęk, G.
Rudno-Rudziński, W.
Misiewicz, J.
Wojcik, J.
Robinson, B. J.
Thompson, D. A.
Mascher, P.
Powiązania:
https://bibliotekanauki.pl/articles/2035600.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.Hs
78.67.-n
66.10.Cb
Opis:
Non-square quantum wells in electric field have been investigated by photoreflectance and photoluminescence spectroscopies. The structures have been obtained by a post-growth modification (rapid thermal annealing) of standard 1.55μm InGaAsP-based laser structures that were grown by gas source molecular beam epitaxy. During rapid thermal annealing a migration of semiconductor atoms across quantum well interfaces changes the quantum well profile from a square well to a rounded well. The modification of the profile changes energy levels in the quantum well and in consequence a blue shift of the quantum well emission peak is observed in photoluminescence. In this paper the blue shift of the ground state transition of post-growth modified quantum well structures has been investigated by both photoluminescence and photoreflectance techniques. Also a blue shift of excited state transitions has been observed in photoreflectance spectra. Generally, a stronger blue shift for the ground state transition than for excited state transitions has been observed. Additionally, oscillator strengths for all quantum well transitions have been determined from photoreflectance spectra. It has been found that the oscillator strength is constant for all quantum well transitions despite of modification of the quantum well profile.
Źródło:
Acta Physica Polonica A; 2002, 102, 4-5; 649-657
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Correlated Electron Systems of Different Dimensionalities
Autorzy:
Kurzyk, J.
Wójcik, W.
Spałek, J.
Powiązania:
https://bibliotekanauki.pl/articles/1812297.pdf
Data publikacji:
2008-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.27.+a
71.30.+h
71.10.Fd
Opis:
The optimized single-particle wave functions contained in the parameters of the Hubbard model (hopping integral t and intraatomic interaction U) are determined explicitly in the correlated state for electronic systems of various symmetries and dimensions: Hubbard chain, square and triangular lattices, and the three cubic lattices: SC, BCC, and FCC. In effect, the electronic properties of these structures as a function of the interatomic distance R are obtained. In most cases, the model parameters do not scale linearly with the lattice constant. Also, the atomic part of the total ground state energy changes with the U/t ratio and therefore should be (and is) included in the analysis. The solutions of dimensions D>1 are analyzed by utilizing the approximate Gutzwiller treatment.
Źródło:
Acta Physica Polonica A; 2008, 114, 1; 175-178
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimized Wannier Functions for Hubbard Chain
Autorzy:
Kurzyk, J.
Wójcik, W.
Spałek, J.
Powiązania:
https://bibliotekanauki.pl/articles/1810395.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.27.+a
71.30.+h
71.10.Fd
Opis:
One-dimensional atomic chain with a variable-range hopping is described within the extended Hubbard model. The Gutzwiller-ansatz approximation is used to determine the optimized single-particle (Wannier) wave functions in the correlated state. Hopping integral up to the third neighbors is taken into account and the results are compared with those for the infinite hopping range. Ground state energy of the system is compared with that making use of the rigorous Lieb-Wu solution with the optimized wave functions. The evolution of the properties as a function of interatomic distance is discussed.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 114-116
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Trion Binding Energies and Wave Functions in Doped Quantum Wells
Autorzy:
Gładysiewicz, A.
Wójcik, K.
Wójs, A.
Quinn, J. J.
Powiązania:
https://bibliotekanauki.pl/articles/2043713.pdf
Data publikacji:
2005-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.35.Pq
71.35.Ji
Opis:
The energy spectra of negative trions (X$\text{}^{-}$=2e+h) in one-sided doped GaAs quantum wells are calculated. The maps of the trion binding energyΔ as a function of well width w, electron concentration n, and the magnetic field B are obtained. The dependence of the trion ground state ("bright singlet" versus "dark triplet") on those parameters is established.
Źródło:
Acta Physica Polonica A; 2005, 108, 4; 669-674
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Scale Invariance of Principle of Equivalent Utility under Cumulative Prospect Theory
Autorzy:
Chudziak, J.
Halicki, M.
Wójcik, S.
Powiązania:
https://bibliotekanauki.pl/articles/1388334.pdf
Data publikacji:
2015-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
89.65.Gh
Opis:
In 1984 A. Reich proved that under Expected Utility Theory, a scale invariance of the Principle of Equivalent Utility just for two particular values of parameters implies its scale invariance. In this paper, we extend this result onto the Principle of Equivalent Utility under Cumulative Prospect Theory.
Źródło:
Acta Physica Polonica A; 2015, 127, 3A; A-29-A-32
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulation of Spin-Dependent Electronic Transport through Resonant Tunnelling Diode with Paramagnetic Quantum Well
Autorzy:
Wójcik, P.
Spisak, B. J.
Wołoszyn, M.
Adamowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/2048076.pdf
Data publikacji:
2011-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.25.Dc
73.63.-b
Opis:
The spin-dependent electronic transport is investigated in a paramagnetic resonant tunnelling diode formed from Zn$\text{}_{1 - x}$Mn$\text{}_{x}$Se quantum well between two ZnBeSe barrier layers. The spin-dependent current-voltage characteristics have been obtained in the presence of magnetic fields by solving the quantum kinetic equation for the Wigner distribution function and the Poisson equation in the self-consistent procedure. We have obtained two distinct current peaks due to the giant Zeeman splitting of electronic levels in a qualitative agreement with experiment. We have shown that the sign of spin current polarization can be reversed by tuning the bias voltage. Moreover, we have found the bias voltage windows with a nearly constant polarization.
Źródło:
Acta Physica Polonica A; 2011, 119, 5; 648-650
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Monotropic Character of Polymorphism in Pentachloropyridine Crystal Studied by Calorimetric and Spectroscopic Methods
Autorzy:
Wójcik, G.
Giermańsκa-Kahn, J.
Marqueton, Y.
Foulon, M.
Powiązania:
https://bibliotekanauki.pl/articles/1933583.pdf
Data publikacji:
1995-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.70.Kb
78.30.-j
Opis:
Pentachloropyridine crystals in two polymorphic modifications: tetragonal and monoclinic were studied by differential scanning calorimetry and polarized IR and Raman spectroscopy in 20 to 200 cm$\text{}^{-1}$ region and at different temperatures from melting point down to the liquid nitrogen temperature. The 4 K difference in melting points of both forms indicates the occurrence of monotropy. The spectra were discussed in terms of positional disorder in the studied crystals which often happen to be mixtures of the monoclinic crystal and the L- and D-forms of the tetragonal one. The monotropic transition of the metastable tetragonal crystal into the stable monoclinic one was observed in the Raman spectra and under the polarizing microscope at temperatures ranging from 170 to 185 K and as an anomaly on the differential scanning calorymetry diagram at 193 K.
Źródło:
Acta Physica Polonica A; 1995, 88, 2; 339-347
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin Conductance of Nanowires with Double Coupled Quantum Dots
Autorzy:
Wołoszyn, M.
Spisak, B.
Wójcik, P.
Adamowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1398537.pdf
Data publikacji:
2016-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.25.Dc
73.63.Nm
Opis:
Using the computer simulations we have studied the spin conductance of the InAs nanowire with three all-around gates that generate two coupled quantum dots in the nanowire. We have assumed that the same constant voltage is applied to the outermost (left and right) gates and investigated the effect of the varying central-gate voltage (V_{G}) and axially directed magnetic field B on the spin currents. The calculated spin-up and spin-down conductances exhibit pronounced oscillations as functions of V_{G}. In certain intervals of V_{G}, both the spin conductances oscillate in antiphase, which can be applied to the spin-filter operation.
Źródło:
Acta Physica Polonica A; 2016, 129, 1a; A-114-A-116
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Strongly Correlated Electrons in a Magnetic Field: Fermi Liquid versus Spin Liquid
Autorzy:
Spałek, J.
Wójcik, W.
Powiązania:
https://bibliotekanauki.pl/articles/1930575.pdf
Data publikacji:
1994-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.28.-d
75.10.Lp
Opis:
We compare the Fermi liquid (FL) and statistical spin liquid (SSL) representations of the electronic properties for strongly correlated systems. In particular, we discuss the entropy, as well as the magnetization as a function of band filling, temperature and magnetic field. These properties are quite different in the two (FL, SSL) states. Antiferromagnetic state disappears for a small number of holes in the doped Mott insulator.
Źródło:
Acta Physica Polonica A; 1994, 85, 2; 357-361
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Correlation Induced Optimization of Wave Functions: the Hubbard Chain
Autorzy:
Spałek, J.
Podsiadły, R.
Wójcik, W.
Powiązania:
https://bibliotekanauki.pl/articles/2013007.pdf
Data publikacji:
2000-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.10.Fd
71.15.Fv
31.25.Nj
Opis:
We determine the explicit form of the single-particle Wannier functions {w$\text{}_{i}(r)}$ appearing in the parameters of quantum models. The method is illustrated on the example of the Hubbard chain, for which we derive the renormalized wave equation starting from a variational principle and by treating the system ground state energy as a functional of {w$\text{}_{i}(r)}$ and their derivatives. In this manner, the optimized basis is obtained only after the electronic correlations have been included in the rigorous Lieb-Wu solution. The results for the ground state energy and the size of the renormalized s-type orbitals, both as a function of interatomic distance, are calculated explicitly.
Źródło:
Acta Physica Polonica A; 2000, 97, 3; 381-384
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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