It is well known that the similar universal behavior of infinite-size (bulk) systems of different nature requires the same basic conditions: space dimensionality; number components of order parameter; the type (short-or longrange) of the intermolecular interaction; symmetry of the fluctuation part of thermodynamical potential. Basic conditions of similar universal behavior of confined systems needs the same supplementary conditions such as the number of monolayers for a system confinement; low crossover dimensionality, i.e., geometric form of restricted volume; boundary conditions on limiting surfaces; physical properties under consideration. This review paper is aimed at studying all these conditions of similar universal behavior for diffusion processes in confined liquid systems. Special attention was paid to the effects of spatial dispersion and low crossover dimensionality. This allowed us to receive receiving correct nonzero expressions for the diffusion coefficient at the critical point and to take into account the specific geometric form of the confined liquid volume. The problem of 3D⇔2D dimensional crossover was analyzed. To receive a smooth crossover for critical exponents, the Kawasaki-like approach from the theory of mode coupling in critical dynamics was proposed. This ensured a good agreement between data of computer experiment and theoretical calculations of the size dependence of the critical temperature T c (H) of water in slitlike pores. The width of the quasi-elastic scattering peak of slow neutrons near the structural phase transition in the aquatic suspensions of plasmatic membranes (mesostructures with the typical thickness up to 10 nm) was studied. It was shown that the width of quasi-elastic peak of neutron scattering decreases due to the process of cell proliferation, i.e., with an increase of the membrane size (including the membrane thickness). Thus, neutron studies could serve as an additional diagnostic test for the process of tumor formation.
Despite symmetrical polarization, the magnitude of a light-induced voltage is known to be asymmetric with respect to poling sign in many photovoltaic (PV) ferroelectrics (FEs). This asymmetry remains unclear and is often attributed to extrinsic effects. We show here for the first time that such an asymmetry can be intrinsic, steaming from the superposition of asymmetries of internal FE bias and electro-piezo-strictive deformation. This hypothesis is confirmed by the observed decrease of PV asymmetry for smaller FE bias. Moreover, the both PV effect and remanent polarization are found to increase under vacuum-induced expansion and to decrease for gas-induced compression, with tens percents tunability. The change in cations positions under pressure is analysed through the first-principle density functional theory calculations. The reported properties provide key insight for FE-based solar elements optimization.
Using density functional theory calculations, we studied structural, electronic and adsorption properties of CO and H 2 adsorption on the Pt-doped (ZnO) 12 nanoclusters. The more suitable position for the Pt atom is its lateral doping on the nanocluster surface. The lower energy gap for the Pt-doped (ZnO) 12 nanoclusters denotes that their conductivity is higher in comparison with the bare nanocluster. The results showed quite a reasonable increase in CO and H 2 gas molecules adsorption energies on the nanoclusters compared with the pristine (ZnO) 12 due to Pt doping. The sensitivity of the electronic and adsorption properties to the number of molecules was calculated as well. Upon CO adsorption on the Pt-doped (ZnO) 12 nanoclusters energy, it is better when no more than two molecules can be attached to one Pt atom, while H 2 adsorption provides at least three hydrogen molecules on Pt atom. Also, changes in electronic spectra of nanoclusters under the influence of adsorbed CO and H 2 molecules imply a decline in conductivity in such systems. These investigations proved that the Pt-doped (ZnO) 12 nanoclusters can be proposed as an approachable candidate in gas sensors for detecting CO and H 2 gas. Also, the calculation results of H 2 adsorption on Pt-doped (ZnO) 12 nanoclusters can help in consideration of the possibility of hydrogen storage media creation.
The optical constants and thickness of Al-doped ZnO (ZnO:Al(2.5 wt.%)) thin films prepared by high-frequency magnetron sputtering method are determined. ZnO:Al thin films are crystallized in the hexagonal structure from XRD studies. The optical constants and the bandgap of the films under study have been determined. Optical properties (refractive index [Formula: see text], absorption coefficient [Formula: see text], extinction coefficient [Formula: see text], dielectric functions [Formula: see text] and optical conductivity [Formula: see text]) of thin films and thickness [Formula: see text] can be determined from the transmission spectrum. The dispersion of the refractive index was explained using a single oscillator model. Single oscillator energy and dispersion energy are obtained from fitting. Optical parameters of the films were determined using the Cauchy, Sellmeier and Wemple models. The increasing value of dispersion parameter for polycrystalline thin films than for single crystals is observed. The fundamental absorption edge position (3.26 eV) in the transmittance spectrum of studied thin films corresponds to the values that are typical for ZnO:Al compound. No significant increase of the bandgap width was revealed by comparing ZnO:Al thin films with the known results of the optical studies of ZnO thin films. Possible reasons of such behavior were analyzed and the influence of bandgap increase on spectral behavior of optical functions are investigated. The material optical parameters such as normalized integrated transmission, zero and high-frequency dielectric constant, density of state effective mass ratio were also calculated.
Density functional theory calculations of structural, electronic and optical properties of ZnO nanowires were performed. It was established that the band gap of ZnO nanowires increases with decreasing nanowire size. The calculated dielectric functions of ZnO nanowires show a significant blue-shift compared with that of bulk ZnO. Our results provide some information for real understanding of the optical properties of ZnO and also enable more precise monitoring and controlling during the growth of ZnO materials. Moreover, the theoretical calculations of adsorption of different gas molecules on the surface of ZnO nanowires were carried out. In order to define the donor or acceptor character of molecular adsorption, the degree of charge transfer to nanowires was determined.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.