Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "20-27" wg kryterium: Temat

  Lista filtrów
Wyrównaj
Wyświetlanie 1-15 z 37
Tytuł:
Investigation of Energy Deposition and Dose Distributions on Collimator under Photon Beam
Autorzy:
Demir, N.
Kuluöztürk, Z.
Akkurt, İ.
Powiązania:
https://bibliotekanauki.pl/articles/1402435.pdf
Data publikacji:
2015-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
29.27.-a
29.20.Ej
Opis:
The bremsstrahlung photon facility where photon beam can be created via bremsstrahlung processes has been installed in many different accelerator in the world. TARLA (Turkish Accelerator and Radiation Laboratory at Ankara) will be first facility of TAC (Turkish Accelerator Center) project in Turkey. An optimal design of collimator is important for obtain a clean high energy photon beam in a bremsstrahlung facility. In this study the photon spectrum has been obtained depending on the entrance angle of the collimator. The energy deposition and dose distributions on the collimator by photon beam generated from 30 MeV energy electron beam have been calculated with FLUKA Monte Carlo simulation code.
Źródło:
Acta Physica Polonica A; 2015, 128, 2B; B-400-B-402
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of Statistical Spin Liquid Concept to High-Temperature Superconductivity
Autorzy:
Byczuk, K.
Spałek, J.
Powiązania:
https://bibliotekanauki.pl/articles/1930571.pdf
Data publikacji:
1994-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.27.+a
74.20.Mn
Opis:
We apply the concept of statistical spin liquid, in which the doubly occupied quasimomentum configurations {|k⇅⟩} for quasiparticles are excluded from the Fock space, to a planar superconductor with real space pairing. The results compare very well with experimental data for the cuprates, namely (i) the condensed state appears only for the number of holes 0 < δ < 0.15-0.25; (ii) the temperature dependence of the gap is close to the BCS result, but the gap has systematically lower value and is of an extended s-wave form.
Źródło:
Acta Physica Polonica A; 1994, 85, 2; 337-340
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin Polarons in Two-Dimensional Systems
Autorzy:
Morkowski, J. A.
Powiązania:
https://bibliotekanauki.pl/articles/2011229.pdf
Data publikacji:
2000-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.27.+a
72.10.Di
74.20.Mn
Opis:
The problem of motion of holes on a square lattice of antiferromagnetically ordered spins is considered. An overview of the theory of hole dynamics in the antiferromagnetic background is presented. Motion of a single hole is rather well understood both by numerical and analytical methods. For small but finite concentration of holes a treatment analogous to the standard polaron theory is discussed starting with an exact mapping of the t-J Hamiltonian into holon and pseudospin variables.
Źródło:
Acta Physica Polonica A; 2000, 97, 1; 101-110
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Unconventional Superconducting States of an Almost Localized Fermionic Liquid with Nonstandard Quasiparticles: Generalized Gutzwiller Approach
Autorzy:
Kaczmarczyk, J.
Jędrak, J.
Spałek, J.
Powiązania:
https://bibliotekanauki.pl/articles/1536614.pdf
Data publikacji:
2010-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.20.-z
71.27.+a
71.10.Ca
Opis:
We apply the concept of generalized (almost localized) Fermi liquid and associated with it unconventional superconductivity with Cooper pairs composed of quasiparticles with the spin dependent masses (in an applied field) and with the effective field, both induced by electron correlations. The pairing among quasiparticles takes place either in reciprocal space (Sect. 2) or in real space (Sect. 3) and is induced by the kinetic exchange of either superexchange (in the generic narrow-band situation) or Kondo-type interaction (in the Kondo-lattice limit of the periodic Anderson model). While the main features of this type of Fermi liquid have been introduced earlier, we present here a picture which is applicable to both heavy-fermion and high-$T_{c}$ superconductivity within a single narrow-band representation of correlated states. Our approach introduces a set of additional concepts (spin-dependent masses, effective fields induced by electron correlations), for which the Landau concept of the Fermi liquid represents still a workable scheme. In the limit of the Kondo lattice, we present the phase diagram incorporating the Fulde-Ferrell-Larkin-Ovchinnikov phase within the BCS-type of pairing, whereas in that of the t-J model we show that the proper choice of renormalization factors and constraints is crucial for the mean-field description of the superconducting state.
Źródło:
Acta Physica Polonica A; 2010, 118, 2; 261-266
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
First-Principles Study of Kondo Insulator $SmB_{6}$
Autorzy:
Gmitra, M.
Čenčariková, H.
Farkašovský, P.
Powiązania:
https://bibliotekanauki.pl/articles/1369765.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.28.+d
71.20.-b
71.27.+a
Opis:
We applied the Perdew-Burke-Ernzerhof hybrid functional (PBE0) within the density functional theory (DFT) to study electronic properties of the heavy fermion Kondo semiconductor $SmB_{6}$. The calculation of the Hartee-Fock exchange contribution to the exact-exchange within the atomic sphere approximation for bulk $SmB_{6}$ represents a computationally efficient, parameter-free method that provides good qualitative and quantitative agreement with photoemission experiments. Specifically, we found an energy difference of 7 eV between the occupied and unoccupied correlated Sm f states. Furthermore, the spin-orbit coupling yields a splitting of the occupied Sm f states of about 1 eV in agreement with recent angular resolved photoemission spectroscopy. The electronic spectrum in the vicinity of the X point shows a hybridization between the Sm 5d conduction band and the localized Sm 4f states at the Fermi level. This might lead to a transport gap opening.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 298-299
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Intriguing Magnetoresistivity of $URh_{0.62}Ru_{0.38}Ge$ in the Non-Fermi Liquid Regime
Autorzy:
Miiller, W.
Tran, V.
Powiązania:
https://bibliotekanauki.pl/articles/1810409.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.10.Hf
71.20.Lp
71.27.+a
Opis:
Magnetoresistivity of $URh_{0.62}Ru_{0.38}Ge$ solid solution was measured in the temperature range 0.35-300 K and in magnetic fields up to 9 T. For the studied system, which lies on the border of ferromagnetism, we observe positive magnetoresistivity in the non-Fermi liquid regime. The finding is in striking disagreement with scenario predicted for ferromagnetic quantum critical point.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 144-146
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Anisotropy of Magnetic and Transport Properties οf $UAuSb_2$ Single Crystals
Autorzy:
Troć, R.
Bukowski, Z.
Stępień-Damm, J.
Sułkowski, C.
Powiązania:
https://bibliotekanauki.pl/articles/1810449.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Lp
71.27.+a
75.30.Gw
Opis:
The uranium-gold diantimonide $UAuSb_2$ belongs to a numerous family of ternary compounds crystallizing in a tetragonal structure of the $HfCuSi_2$-type (space group P4/nmm). In this paper the results of magnetization, electrical resistivity and thermopower measured along the main crystallographic directions are reported. Two magnetic transitions, a ferromagnetic one at $T_C$ =31 K and probably an antiferromagnetic one at $T_N$ = 43 K were found. The spontaneous magnetization at 1.9 K amounts about 0.8 $μ_B$ for B ∥ c-axis. Electrical resistivity for j ⊥ c-axis exhibits a $T^2$ exp(-Δ/kT) dependence at low temperatures and a Kondo effect at higher temperatures above $T_N$. The thermopower S for both main crystallographic directions shows a maximum at the temperature close to $T_C$ and the lack of any anomaly at $T_N$.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 181-184
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theory of Unconventional Superconductivity in Strongly Correlated Systems: Real Space Pairing and Statistically Consistent Mean-Field Theory - in Perspective
Autorzy:
Spałek, J.
Powiązania:
https://bibliotekanauki.pl/articles/1431227.pdf
Data publikacji:
2012-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.27.+a
74.70.Tx
74.20.-z
Opis:
In this brief overview we discuss the principal features of real space pairing as expressed via corresponding low-energy (t-J or periodic Anderson-Kondo) effective Hamiltonian, as well as consider concrete properties of those unconventional superconductors. We also rise the basic question of statistical consistency within the so-called renormalized mean-field theory. In particular, we provide the phase diagrams encompassing the stable magnetic and superconducting states. We interpret real space pairing as correlated motion of fermion pair coupled by short-range exchange interaction of magnitude J comparable to the particle renormalized band energy ≈ tx, where x is the carrier number per site. We also discuss briefly the difference between the real-space and the paramagnon-mediated sources of superconductivity. The paper concentrates both on recent novel results obtained in our research group, as well as puts the theoretical concepts in a conceptual as well as historical perspective. No slave-bosons are required to formulate the present approach.
Źródło:
Acta Physica Polonica A; 2012, 121, 4; 764-784
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Formation of Accelerated Particle Beam in Isochronous Cyclotron
Autorzy:
Voronin, A.
Partyka, J.
Aldibekova, A.
Powiązania:
https://bibliotekanauki.pl/articles/1381861.pdf
Data publikacji:
2014-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
29.27.Bd
29.20.dg
41.85.-p
Opis:
In the paper there are given calculated and experimental data which allow to form necessary beam parameters for a precise experiment in nuclear physics. An intensity of a beam extracted from an isochronous cyclotron acceleration chamber ($E_{p}$ = 30 MeV) can reach 15 μA with an energy spread of 3 × $10^{-3}$. Accelerated ion beams of such kind are widely applicable in nuclear physical experiments.
Źródło:
Acta Physica Polonica A; 2014, 125, 6; 1408-1411
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pairing Scenarios for the Hubbard Model in the Strong Coupling Limit
Autorzy:
Apinyan, V.
Kopeć, T.
Powiązania:
https://bibliotekanauki.pl/articles/1812294.pdf
Data publikacji:
2008-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.27.+a
71.10.Fd
74.20.Rp
Opis:
We consider a spin-rotationally invariant Hubbard model. The original electron operator is presented in the charge-spin-fermion U(1)×SU(2) factorized form. The factorization procedure is given in terms of the emergent gauge fields. As a result, the electron appears like a composite object consisting of strongly fluctuating phase field and spatially rotating spin axis. Furthermore, we elaborate microscopically on the form of possible pairing states.
Źródło:
Acta Physica Polonica A; 2008, 114, 1; 159-163
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heat Capacity of Heavy Fermion Compound $CeCu_4Ga$ in High Magnetic Fields
Autorzy:
Kowalczyk, A.
Toliński, T.
Reiffers, M.
Zapotoková, M.
Falkowski, M.
Gažo, E.
Powiązania:
https://bibliotekanauki.pl/articles/1810399.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
65.40.Ba
71.20.Eh
71.27.+a
Opis:
The heat capacity in the applied magnetic field up to 9 T, susceptibility and magnetization of polycrystalline $CeCu_{4}Ga$ are presented. Magnetic ordering was not observed down to 2 K. For temperature T < 200 K a Curie-Weiss behavior is observable giving an effective magnetic moment $μ_\text{eff}$ =2.53 $μ_{B}$/f.u. The experimental value of $μ_\text{eff}$ is close to the calculated one for a free $Ce^{3+}$ ion ($μ_\text{eff}$ = 2.54 $μ_{B}$/f.u.), thus indicating the presence of well localized magnetic moments carried by the stable $Ce^{3+}$ ions. At low temperatures the electronic heat capacity coefficient value depends strongly on the temperature range used for the extrapolation and applied magnetic field. We observe a typical heavy fermion behavior with γ value of about 380 mJ $\text{mol}^{-1} K^{-2}$ obtained from extrapolation to T = 0 K of the temperature range above 7 K. However, extrapolation of the lowest temperatures range yields the γ value of 3.3 J $\text{mol}^{-1} K^{-2}$.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 123-125
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Superconductivity in Hubbard Model with Correlated Hopping
Autorzy:
Bułka, B. R.
Robaszewska, M.
Powiązania:
https://bibliotekanauki.pl/articles/1955520.pdf
Data publikacji:
1997-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.27.+a
71.30.+h
74.20.Mn
Opis:
Using the slave-boson method in its spin- and charge-rotational invariant representation we determine stability of the superconducting state in the Hubbard model with correlated hopping. In general the term with correlated hopping violates electron-hole symmetry, however, in the special case when the correlated hopping integral X is equal to the uncorrelated hopping integral t the electron-hole symmetry remains. We investigate this case and show that correlations induced by onsite Coulomb interactions U yield to the normal state with exactly single occupied sites (corresponding to |U=∞⟩). The phase diagram of the superconducting state is determined for the different electron concentration n. At the half-filled band (n=1) a direct transition from the Mott insulator to the superconducting state occurs.
Źródło:
Acta Physica Polonica A; 1997, 91, 2; 363-366
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effects of Relativistic Warm Plasma Waveguide and High Frequency Electrical Field on Beam-Plasma Interaction
Autorzy:
El-Shorbagy, Kh. H.
Powiązania:
https://bibliotekanauki.pl/articles/2047358.pdf
Data publikacji:
2007-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
52.27.Ny
52.35.-g
94.20.wf
Opis:
The paper is concerned with investigation of the influence of an intense high frequency electric field and relativistic warm plasma waveguide on electrostatic oscillations of nonuniform bounded plasma. The stabilizing effect of a strong high frequency (pump) electrical field on beam-plasma interaction in a cylindrical relativistic warm plasma waveguide is discussed. A new mathematical technique "separation method" was applied to the two-fluid plasma model to separate the equations, which describe the system, into two parts, time and space parts. Plasma electrons are considered to have a relativistic, thermal velocity. It is shown that a high frequency electric field has no essential influence on dispersion characteristics of unstable surface waves excited in a relativistic warm plasma waveguide by a low-density electron beam. The region of instability is only slightly narrowing and the growth rate decreases by a small parameter and this result was reduced comparing to cold, nonrelativistic plasma. Also, it is found that the plasma electrons did not affect the solution of the space part of the problem.
Źródło:
Acta Physica Polonica A; 2007, 112, 1; 41-48
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin Polarons in Antiferromagnetic Planes
Autorzy:
Morkowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/2047298.pdf
Data publikacji:
2007-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.27.+a
72.10.Di
74.20.Mn
Opis:
In the lecture the theory of spin polarons is reviewed on the basis of its analogy with the theory of lattice polarons. The energy dispersion curve for a single polaron in a two-dimensional antiferromagnetic square lattice is calculated in the self-consistent Born approximation. Also in self-consistent Born approximation the energy of a pair of interacting spin polarons is calculated. The results of calculations for realistic values of parameters of the model lead to the conclusion that pairing of spin polarons is not a likely mechanism of superconductivity in cuprates.
Źródło:
Acta Physica Polonica A; 2007, 111, 4; 397-408
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Properties and Electronic Structure of CeTIn (T = Ni, Cu, Pd, Au) Compounds
Autorzy:
Szytuła, A.
Penc, B.
Gondek, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/2047306.pdf
Data publikacji:
2007-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Eh
71.27.+a
75.20.Hr
79.60.-i
Opis:
The electronic structure of the ternary CeTIn (T = Ni, Cu, Pd, Au) compounds was investigated by means of X-ray photoelectron spectroscopy. Our interest was aimed mainly to the valence bands and the Ce3d core levels of investigated compounds. Analysis of the valence bands indicates that they are mainly determined by the Tnd band, whereas a share of the R4f states can be estimated to be about a few percent only. The analysis of the differential valence bands spectra between CeTIn and LaTIn analogues suggests that the Ce4f$\text{}^{1}$ ground states shift deeper below the Fermi level with an increase in the 4f level occupation factor. The analysis of the Ce3d spectra made on the basis of the Gunnarsson-Schönhammer model indicates the hybridization parameter equal to 148 meV for CeNiIn, 45 meV for CeCuIn, 177 meV for CePdIn, and 123 meV for CeAuIn.
Źródło:
Acta Physica Polonica A; 2007, 111, 4; 475-486
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 37

Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies