Informacja

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

Wyszukujesz frazę "DG" wg kryterium: Temat


Tytuł:
Vibration and Luminescence Spectroscopic Investigations of the Alkali Rare Earth Double Phosphates M$\text{}_{3}$(RE,Eu)(PO$\text{}_{4}$)$\text{}_{2}$ (M=K, Rb; RE=La, Gd)
Autorzy:
Kloss, M.
Schwarz, L.
Hölsä, J. P. K.
Powiązania:
https://bibliotekanauki.pl/articles/1995573.pdf
Data publikacji:
1999-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.50.-f
61.66.Fn
63.20.-e
71.20.Dg
71.20.Eh
71.70.-d
78.30.-j
78.55.-m
Opis:
The room temperature IR- and Raman spectra of the different M$\text{}_{3}$RE(PO$\text{}_{4}$)$\text{}_{2}$ (M = K, Rb; RE = La, Eu, Gd) double phosphates were analysed and used to interpret the vibronic side band structure in the photoluminescence spectra. The intraconfigurational 4f-4f electronic transitions in the photoluminescence spectra of the Eu$\text{}^{3+}$ doped M$\text{}_{3}$RE(PO$\text{}_{4}$)$\text{}_{2}$ were analysed in detail. The crystal field fine structure of the $\text{}^{5}$D$\text{}_{0}$ → $\text{}^{7}$F$\text{}_{J}$ (J=0-4) transitions was analysed accounting for the information on the crystal structure. The effect of the temperature as well as the alkali host cation was evaluated. Finally, a preliminary crystal field energy level scheme for the $\text{}^{7}$F$\text{}_{J}$ (J=0-4) ground term was deduced from the analysis of the photo-luminescence as well as IR- and Raman spectra.
Źródło:
Acta Physica Polonica A; 1999, 95, 3; 343-349
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Three localized f electrons in UPd₂Al₃ and in UGe₂ intermetallics
Autorzy:
Radwanski, R.
Nalecz, D.
Ropka, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1062036.pdf
Data publikacji:
2016-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.70.Ej
75.10.Dg
75.30.Gw
Opis:
We have calculated the strength of the excitations between the crystal-field states which are in agreement with inelastic-neutron-scattering results. This agreement confirms the existence in the heavy-fermion superconductor UPd₂Al₃ the crystal-field electronic structure being the finger-print of the U^{3+} ions with three localized f electrons forming strongly-correlated atomic-like quantum system 5f³. The ionic integrity and the low-energy crystal-field electronic structure is preserved in this metallic system in the meV scale as has been postulated in the Quantum Atomistic Solid State theory (QUASST). We provide preliminary results with the U^{3+} ion in UGe₂ showing the ground-state eigenfunction which reproduces the ordered magnetic-moment value of 1.48 μ_{B}. This moment is composed from the dominant orbital contribution (2.6 μ_{B}) and the opposite spin moment (1.12 μ_{B}).
Źródło:
Acta Physica Polonica A; 2016, 130, 2; 545-550
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermodynamic Properties of Geometrically Frustrated S=1/2 XY Antiferromagnet $Er_{2}Sn_{2}O_{7}$
Autorzy:
Al Ghamdi, N.
Orendáčová, A.
Pavlík, V.
Orendáč, M.
Powiązania:
https://bibliotekanauki.pl/articles/1368676.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.10.Dg
75.50.Ee
75.30.Sg
Opis:
The magnetic susceptibility, specific heat and entropy of geometrically frustrated S=1/2 XY antiferromagnet $Er_{2}Sn_{2}O_{7}$ are reported. It is shown, that temperature dependence of magnetic susceptibility above nominally 10 K is governed by crystal field effects. Systematic study of specific heat in magnetic fields up to 7 T enabled the estimation of exchange coupling, J/k<<4.6 K. Investigation of isothermal change of magnetic entropy upon magnetization from 1 T to 7 T revealed the absence of enhanced magnetocaloric effect. The obtained results suggest that frustration parameter f ≈140 proposed for $Er_{2}Sn_{2}O_{7}$ earlier may be significantly overestimated.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 264-265
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal Stability and Mechanism of Thermally Induced Crystallization of $Fe_{73.5}Cu_1Nb_3Si_{15.5}B_7$ Amorphous Alloy
Autorzy:
Vasić, M.
Minić, D.
Blagojević, V.
Žák, T.
Pizúrová, N.
David, B.
Powiązania:
https://bibliotekanauki.pl/articles/1402117.pdf
Data publikacji:
2015-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.70.dg
64.70.kd
64.70.pe
Opis:
Investigation of thermal stability of the alloy revealed stepwise crystallization process, manifested by two distinct complex exothermic peaks in differential scanning calorimetry curves. Kinetic parameters of individual crystallization steps were found using the Kissinger and Vyazovkin methods. Structural characterization of thermally treated samples showed formation of different iron-based phases including α-Fe(Si), Fe₂B, Fe₁₆Nb₆Si₇ and Fe₂Si and some metastable intermediary species. Morphology characterization of the surface and cross-section of the thermally treated samples showed granulated structure composed of several different phases and indicated occurrence of impingement effects during crystal growth. Value of estimated lifetime suggested very high stability against crystallization at room temperature and abrupt decrease of lifetime with temperature increase.
Źródło:
Acta Physica Polonica A; 2015, 128, 4; 657-660
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical Studies on the Local Structure and Spin Hamiltonian Parameters for Single Cu²⁺ Ion in BaF₂
Autorzy:
Lin, J.
Xiao, P.
Zhao, Y.
Zhang, B.
Yang, Y.
Powiązania:
https://bibliotekanauki.pl/articles/1398965.pdf
Data publikacji:
2016-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.10.Dg
76.30.Fc
Opis:
The spin Hamiltonian parameters (g-factors and the hyperfine structure constants) and local structure are theoretically studied for single Cu²⁺ ion in BaF₂ from the high-order perturbation formulae of these parameters for 3d⁹ ions in tetragonally elongated octahedra. In the calculations, the ligand orbital and spin-orbit coupling of the impurity Cu²⁺ are taken into account, based on the cluster approach. Due to the Jahn-Teller effect and size mismatching substitution, the impurity Cu²⁺ is found to be located at a distance of about 0.2 Å from the nearest fluorine plane. The signs of the hyperfine structure constants $A_∥ $ and $ A_⊥ $ are suggested. The theoretical spin Hamiltonian parameters based on the above local structure are in good agreement with the observed values.
Źródło:
Acta Physica Polonica A; 2016, 129, 6; 1173-1177
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical Studies of ESR Parameters and Local Lattice Structure of the Vanadate-Lithium-Borate Glasses
Autorzy:
Feng, W.
Zhao, M.
Li, T.
Zhang, X.
Xue, J.
Powiązania:
https://bibliotekanauki.pl/articles/1419845.pdf
Data publikacji:
2012-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.70.Ch
75.10.Dg
61.72.Bb
76.30.Fc
Opis:
Electron spin resonance spectral parameters of $V^{4+}$ ions in vanadate-lithium-borate glasses have been calculated by the crystal-field theory. The theoretical results are $g_{∥ }$ = 1.940, $g_{⊥}$ = 1.983 and $A_{∥ } = -175 \times 10^{-4} cm^{-1},$ $A_{⊥} = -65 \times 10^{-4} cm^{-1}$ which are good agreement with the experimental values ($g_{∥ }$ = 1.939(3), $g_{⊥}$ = 1.998(3) and $A_{∥ } = (170.6-176.4) \times 10^{-4} cm^{-1},$ $A_{⊥} = (61.3-71.4) \times 10^{-4} cm^{-1}$). In addition, the bond lengths of the local lattice structure are, respectively, $R_{∥ }$ = 1.5 Å and $R_{⊥}$ = 1.95 Å which have been shown to have a compressed tetrahedral geometry along the $C_4$ axis.
Źródło:
Acta Physica Polonica A; 2012, 122, 1; 167-169
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical Explanations of the Optical Band Positions and Local Structure for $Cu^{2+}$ Centers in $ZnO-Bi_{2}O_{3}-B_{2}O_{3}-CuO$ Glasses
Autorzy:
Yuan, M.
Powiązania:
https://bibliotekanauki.pl/articles/1377767.pdf
Data publikacji:
2014-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.Bb
75.10.Dg
76.30.-v
76.30.Fc
Opis:
The local structure, two optical band positions and three electronic spin resonance parameters for $Cu^{2+}$ centers at the tetragonally-distorted octahedral sites in $ZnO-Bi_2O_3-B_2O_3-CuO$ glasses are calculated from the high-order perturbation method based on the two-spin-orbit-parameter model, where the contributions from both the spin-orbit coupling parameters of central $d^{n}$ ion and ligand ion are included. The theoretical results are in good agreement with the experimental values. The calculations show that the high-order perturbation method based on the two-spin-orbit-parameter model is effective in the explanations of optical spectra, electronic spin resonance parameters and local distortion structure for $d^{9}$ ions in glasses.
Źródło:
Acta Physica Polonica A; 2014, 126, 6; 1293-1295
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Systematic Variation of Optical Properties of Alkali Halides: an Ab Initio Study
Autorzy:
Gonçalves, G. C.
Lalic, M. V.
Malta, O. L.
Powiązania:
https://bibliotekanauki.pl/articles/2047877.pdf
Data publikacji:
2007-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Dg
78.20.Ci
Opis:
In this paper we study a correlation between the optical properties, electronic structure and anion-cation electronegativity difference in three groups of alkali halides MX (M = Li, Na, K; X = F, Cl, Br, I). The electronic structure was calculated by first-principle, density-functional theory based full-potential linear augmented plane wave method. Then the complex dielectric function was computed, allowing determination of the optical absorption spectra in all compounds, up to incident radiation energy of 40 eV. The results were interpreted in terms of calculated band structures and correlated with the electronegativity difference in each compound, which was estimated on the basis of topological theory of Bader.
Źródło:
Acta Physica Polonica A; 2007, 112, 5; 1043-1048
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Structural and Electronic Properties of BaO under Epitaxial Strains: First-Principles Calculations
Autorzy:
Yang, Xiong
Wang, Ying
Chen, Yifei
Yan, Huiyu
Powiązania:
https://bibliotekanauki.pl/articles/1191222.pdf
Data publikacji:
2016-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Dg
71.70.Fk
71.15.Mb
Opis:
The structural and electronic properties of alkaline-earth oxide BaO under epitaxial strains are investigated using a first principles density functional theory. The electronic structure is particularly sensitive to the compressive or tensile strain, e.g., the splitting of energy band, the increase of the total density of state, and the shift of the partial density of states. Especially, the trends in the variation of the optical band gap are predicted by two different exchange-correlation potential schemes. Our results indicate that the optical band gaps undergo a decrease for both compressive and tensile strains.
Źródło:
Acta Physica Polonica A; 2016, 129, 1; 64-68
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect of Water Accessible Paramagnetic Ions on Subcellular Structures Formed in Developing Wheat Photosynthetic Membranes as Observed by NMR and by Sorption Isotherm
Autorzy:
Harańczyk, H.
Leja, A.
Strzałka, K.
Powiązania:
https://bibliotekanauki.pl/articles/2044747.pdf
Data publikacji:
2006-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
82.56.Na
87.16.Dg
Opis:
The rehydration from the gaseous phase of the developing native or EDTA-washed from unbound and loosely bound paramagnetic ions wheat thylakoid membrane lyophilizate was investigated using hydration kinetics, sorption isotherm, and high power proton relaxometry. Hydration time courses are single exponential for all target humidities. The sorption isotherm is well fitted by the Dent model, with the mass of water saturating primary binding sites equal toΔ M/m$\text{}_{ }$0=0.024 and 0.017 for native and EDTA-washed membranes, respectively. Proton free induction decays distinguish: (i) a Gaussian component, S$\text{}_{0}$, coming from protons of solid matrix of lyophilizate; (ii) a Gaussian component, S$\text{}_{1}$, from water bound to the primary water binding sites in proximity of water accessible paramagnetic ions; (iii) an exponentially decaying contribution, $L$\text{}_{1}$$, from water tightly bound to lyophilizate surface; and (iv) exponentially decaying loosely bound water pool, L$\text{}_{2}$. Sorption isotherm fitted to NMR data shows a significant contribution of water "sealed" in membrane structures (Δ M$\text{}_{s}$/m$\text{}_{0}$=0.052 for native and 0.061 for EDTA-washed developing membranes, respectively).
Źródło:
Acta Physica Polonica A; 2006, 109, 3; 389-398
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Technical and Economical Evaluation of Proton Exchange Merobrane (PEM) Fuel Cell for Commercial Applications
Autorzy:
Katyara, S.
Iżykowski, J
Staszewski, Ł
Shaikh, F.
Powiązania:
https://bibliotekanauki.pl/articles/410535.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
Proton Exchange Membrane
PEM
Fuel Cell
DC/DC boost converter
Distributed Generation
DG
polarization curve
efficiency
Opis:
The green energy sources are the utmost needs of today’s world where the reserves of fossil fuel are depleting day by day. The Distributed Generation (DG) has become integral part of power system at commercial level. The most efficient among all DGs and Renewable Energy Sources (RES) is the Fuel Cell (FC) power generation. The fuel cell invariably converts chemical energy directly into electricity. The Fuel cells have normally 60 to 70% efficiency at working conditions. The polarization curve of fuel cell plays important role in improving its efficiency. This research presents the mathematical and Simulink modeling 6 kW, 45 Vdc of Proton Exchange Membrane (PEM) fuel cell. The input thermodynamic parameters of fuel cell are varied and their effects on the output electrical variable are observed. The DC/DC boost converter is used to step up the voltage of fuel cell to 100 Vdc at commercial usable level. A new mathematical equation is presented to improve the efficiency of fuel. The mathematical results are then varied through Simulink results.
Źródło:
Present Problems of Power System Control; 2017, 8; 41-49
2084-2201
Pojawia się w:
Present Problems of Power System Control
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Symmetry Induced Half-Metallic Alkaline Earth Ferromagnets
Autorzy:
Adamowicz, L.
Wierzbicki, M.
Powiązania:
https://bibliotekanauki.pl/articles/1810473.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.15.Mb
71.20.Dg
72.25.Ba
75.10.Lp
Opis:
Search for new half-metallic ferromagnetic binary compounds composed of alkaline earth and III (boron) or IV (carbon) elements is reported. Ab initio all-electron density functional theory calculations in the generalised gradient approximation indicate possibility of half-metallic ferromagnetism. This is a new class of theoretically predicted hypothetical materials, without transition metal elements, not as yet discovered experimentally. Ferromagnetism is expected to be induced by suitable crystalline structure with lattice constant above some critical value. The predominant p electrons mechanism seems to be responsible for the formation and interactions of localised magnetic moments on boron or carbon atoms.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 217-219
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:
Stark and Zeeman Effects in Nd$\text{}_{2}$Fe$\text{}_{14}$B and Pr$\text{}_{2}$Fe$\text{}_{14}$B Intermetallics
Autorzy:
Radwański, R. J.
Franse, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/1945558.pdf
Data publikacji:
1996-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.70.Ej
75.10.Dg
Opis:
The energy level scheme of the Nd$\text{}^{3+}$ and Pr$\text{}^{3+}$ ions in ferromagnetic Nd$\text{}_{2}$Fe$\text{}_{14}$B and Pr$\text{}_{2}$Fe$\text{}_{14}$B intermetallic compounds was evaluated on the basis of all known experiments. In calculations the effect of charge (Stark effect) and spin-dependent (Zeeman effect) interactions were taken into account by means of the crystal-field and molecular-field approximation, respectively. The derived energy level scheme is associated with the removal of the degeneracy of the lowest multiplet given by Hund's rules, i.e. $\text{}^{4}$I $\text{}_{9}\text{}_{/}\text{}_{2}$ (Nd$\text{}^{3+}$) and $\text{}^{3}$H$\text{}_{4}$ (Pr$\text{}^{3+}$). The revealed low-energy electronic structure (<25 meV = 200 cm$\text{}^{-1}$) is associated with many-electron states of the RE$\text{}^{3+}$ ions. Magnetic and electronic properties resulting from this fine structure are compared with all known experimental results. The localized crystal electric field levels exist also in Nd$\text{}_{2}$CuO$\text{}_{4}$, an ionic compound which by doping with Ce becomes high-T$\text{}_{c}$ superconductor, indicating the formation of crystal electric field states independently on the metallic or ionic state.
Źródło:
Acta Physica Polonica A; 1996, 90, 1; 223-232
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin-Spin and Spin-Other-Orbit Interactions of Spin-Hamiltonian Parameters for $3d^{2(8)}$ Ions in $Al_2O_3$ Crystals
Autorzy:
Wei, Q.
Guo, L.
Yang, Z.
Wei, B.
Powiązania:
https://bibliotekanauki.pl/articles/1505102.pdf
Data publikacji:
2011-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.30.Fc
71.70.Ch
75.10.Dg
71.55.Ht
Opis:
By considering weaker magnetic interactions (including spin-spin and spin-other-orbit interactions) in Hamiltonian, the spin-Hamiltonian parameters, including the zero-field splitting parameter D and g factors $(g_∥, g_⊥)$ for $3d^{2(8)}$ ions in $Al_2O_3$ crystals have been investigated. The results show that the contributions to D, $g_∥$ and $g_⊥$ from the spin-orbit interaction are dominant. The contributions from weaker magnetic interactions to D decrease (increase) with increasing charge of impurity ions for $3d^2 (3d^8)$ ions.
Źródło:
Acta Physica Polonica A; 2011, 119, 6; 857-859
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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