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Wyszukujesz frazę "density of states" wg kryterium: Temat


Wyświetlanie 1-8 z 8
Tytuł:
A first-principle study of the effect of Fe/Al impurity defects on the surface wettability of dolomite
Autorzy:
Chen, Hong
Ao, Xianquan
Cao, Yang
Li, Cuiqin
Jiang, Chunyan
Powiązania:
https://bibliotekanauki.pl/articles/2146916.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
density functional theory
phosphate rock flotation
dolomite
surface wettability
density of states
Opis:
The presence of Fe and Al atoms in large quantities in phosphate ores can significantly affect the surface properties of the minerals during flotation. In this study, the effects of Fe/Al impurities on the adsorption of H2O molecules on dolomite, including the density of states (DOS), Mulliken bond group values, and charge groups, were investigated and the adsorption energy was analyzed using density functional theory. The results show that the adsorption of H2O molecules on perfect and Fe/Al-substituted dolomites is weak chemisorption, and the Fe and Al impurities weaken and enhance the adsorption capacity of H2O molecules, respectively. Therefore, the hydrophilicity of the dolomite surface increases in the following order: Fe-substituted dolomite < perfect dolomite < Al-substituted dolomite. The Mulliken charge and bond group analysis shows that the adsorption of H2O molecules on dolomite is primarily through the interaction between Ow and Ca atoms, where the d orbitals of Ca atoms provide charges for Ow atoms to form ionic bonds, which related to the poor electronegativity of Ca atoms and their weak valence electron binding ability. The DOS analysis shows that, during the adsorption of H2O molecules on dolomite, Mg and Al atoms have less influence on the dolomite surface, whereas Fe and Ca atoms undergo competitive adsorption, which inhibits the interaction between Ca atoms and H2O molecules on the dolomite surface.
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 4; art. no. 150702
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Coherent potential approximation technique in a simple example of resistivity calculations for binary alloys
Autorzy:
Wołoszyn, M.
Maksymowicz, A. Z.
Powiązania:
https://bibliotekanauki.pl/articles/1931584.pdf
Data publikacji:
2002
Wydawca:
Politechnika Gdańska
Tematy:
Coherent Potential Approximation
Green function technique
binary alloy
density of states
resistivity
Opis:
Technique of the Coherent Potential Approximation applied for calculations of the density of states in binary alloys Ax B(1-x) is presented. Results of the calculations are also used to find the residual resistivity of the system versus concentration x.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2002, 6, 4; 669-680
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effective energy integral functionals for thin films with three dimensional bending moment in the Orlicz-Sobolev space setting
Autorzy:
Laskowski, Włodzimierz
Nguyen, Hong
Powiązania:
https://bibliotekanauki.pl/articles/729638.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
Γ-convergence
3D-2D dimension reduction
quasiconvex relaxation
minimizers of variational integral functionals
thin films
elastic membranes
effective energy integral functional
bulk and surface energy
equilibrium states of the film
non-power-growth-type bulk energy density
reflexive Orlicz and Orlicz-Sobolev spaces
Opis:
In this paper we consider an elastic thin film ω ⊂ ℝ² with the bending moment depending also on the third thickness variable. The effective energy functional defined on the Orlicz-Sobolev space over ω is described by Γ-convergence and 3D-2D dimension reduction techniques. Then we prove the existence of minimizers of the film energy functional. These results are proved in the case when the energy density function has the growth prescribed by an Orlicz convex function M. Here M is assumed to be non-power-growth-type and to satisfy the conditions Δ₂ and ∇₂.
Źródło:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization; 2016, 36, 1; 7-31
1509-9407
Pojawia się w:
Discussiones Mathematicae, Differential Inclusions, Control and Optimization
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
First-principles calculations of electronic structure of rhodochrosite with impurity
Autorzy:
He, Guichun
Li, Kun
Guo, Tengbo
Li, Shaoping
Huang, Chaojun
Zeng, Qinghua
Powiązania:
https://bibliotekanauki.pl/articles/1449610.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
rhodochrosite
first principles calculations
electronic structure
density of states
Opis:
The electronic structure of rhodochrosite containing impurity defects is studied by using the first principles density functional theory. The energy band structure, density of states and electronic distribution are calculated for rhodochrosite crystal models with various impurities (e.g., Cu, Ca, Mg, Zn, Fe). This paper discusses the effects of such defects on the electronic structure of rhodochrosite. The calculation results show that the impurity defects have a great impact on the surface electrical properties of rhodochrosite. For example, Ca and Mg impurities reduce the semiconductor width of rhodochrosite. Both Ca and Mg atoms in orbital bonding act as electron donors in which Ca3p and Mg2p orbits provide electrons while O2p orbits receive electrons. Moreover, the more number of valence electrons of Mn is the weaker covalent interaction between Mn and O atoms will be. Meanwhile, decrease of the total energy of rhodochrosite, makes the structure more stable. When Fe, Zn and Cu impurities are contained, the forbidden gap becomes narrower, which improves the conductivity of rhodochrosite. In addition, impurity bands will be formed in the 3d orbits of rhodochrosite as shown in its density of states, and the number of electrons in 3d orbits will increase. This weakens the covalence of O atoms, decreases the population values of O-Mn, increases the bond length, and enhances the ionicity of O-Mn bonds. The impurity of all defects considered in this study have shown an improved conductivity of rhodochrosite, and increased hole concentration of Mn atoms, which will be of great benefit to the adsorption of anionic collectors and enhance the electrochemical properties for rhodochrosite flotation process.
Źródło:
Physicochemical Problems of Mineral Processing; 2020, 56, 1; 195-203
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanisms of electrical conductivity, quantum capacity and negative capacitance effects in InSe nanohybrid
Autorzy:
Ivashchyshyn, Fedir
Maksymych, Vitaliy
Calus, Dariusz
Klapchuk, Myroslava
Baryshnikov, Glib
Galagan, Rostislav
Litvin, Valentina
Chabecki, Piotr
Bordun, Ihor
Powiązania:
https://bibliotekanauki.pl/articles/2173564.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
InSe
intercalation
hierarchical structures
impedance spectroscopy
density of states
negative capacity
struktury hierarchiczne
spektroskopia impedancyjna
ujemna pojemność
gęstość stanów
wtrącenie
Opis:
In this work, we present findings on the syntheses and study of properties of InSe nanohybrid. The introduction of guest component in GaSe matrix leads to an increase in inhomogeneities, which is clearly confirmed by the strengthening of the low-frequency horizontal branch of Nyquist diagrams. A constant magnetic field counteracts this effect and changes the behavior of the impedance hodograph at low frequencies to the opposite. Illumination leads to a colossal increase in quantum capacitance, which is clearly demonstrated in the Nyquist diagram. For the synthesized InSe nanohybrid the interesting behavior of the current-voltage characteristic is reported. As a result of studies of the synthesized InSe nanohybrid the effect of “negative capacity” is observed, the magnitude of which can be controlled by the electric field. Based on the constructed impedance model and proposed N-barrier model, the physical mechanisms of the investigated processes are suggested.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2022, 70, 1; e139958, 1--8
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New kind of parameterization applied to the Fermi surface of a crystalline solid. Part II: Density of states and lengths of arcs calculated as a check of the theory
Autorzy:
Roliński, T.
Olszewski, S.
Powiązania:
https://bibliotekanauki.pl/articles/1943221.pdf
Data publikacji:
2009
Wydawca:
Politechnika Gdańska
Tematy:
Fermi surfaces of crystalline solids
electron orbits induced in the magnetic field
density of electron states
orbit lengths and arc lengths on the Fermi surfaces
Opis:
In order to check the validity of parameterization of electron states on the Fermi surfaces developed in the preceding paper, this parameterization is applied to the calculation of some definite crystal properties. The first property is the density of electron states versus energy in simple cubic and body-centered cubic crystal lattices, examined formerly on the basis of the Bloch parameterization of electron states by Jelitto; the other property is the length of some special arcs extended on the surfaces. The parameterizations of both approaches, that of the present paper and that developer on the basis of the Bloch states, are found to give results remaining in remarkable agreement.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2009, 13, 1-2; 117-131
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulation of optical spectra of novel Tl4CdI6 and Tl4HgI6 optoelectronic crystals
Autorzy:
Franiv, V
Bovgyra, O
Kushnir, O
Franiv, A
Plucinski, K J
Powiązania:
https://bibliotekanauki.pl/articles/173547.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
density functional theory
band structure
density of states
optical properties
Opis:
The results of calculations using local density approximation and generalized gradient approximation: the total energy depending on the volume of the unit cell, the distribution of the total density of states and the partial contributions of electronic orbitals in the band structure of Tl4CdI6 and Tl4HgI6 crystals are shown in this paper. The spectra of the real part of the dielectric permittivity, the spectra of the imaginary part of permittivity, the reflection spectra and the absorption coefficient of both crystals are obtained using the Kramers–Kronig method. A comparative analysis of theoretical calculations with experimental data is carried out. Substantial influence of electron–phonon broadening is shown.
Źródło:
Optica Applicata; 2014, 44, 2; 317-326
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The electronic properties of new Fe-based superconductors
Autorzy:
Kruchinin, S.
Antonchenko, V.
Zolotovsky, A.
Powiązania:
https://bibliotekanauki.pl/articles/1934012.pdf
Data publikacji:
2011
Wydawca:
Politechnika Gdańska
Tematy:
Fe-based superconductors
band structure
density of states
critical superconducting transition temperature
Opis:
We investigate the band structure of Fe-based superconductors using the first-principle method of density-functional theory. We calculated the band structure and the density of states at the Fermi level for ReFeAsO (Re = Sm, Dy, Ho, Er) superconductors. Our calculations indicate that the maximum critical superconducting transition temperature Tc will be observed for compounds with Sm and Er. We predict that Tc=60K for ErFeAsO.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2011, 15, 2; 203-208
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

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