Structure of the α–β Interface in a PdCu Solid Solution

Physics of the Solid State - In accordance with the orientation ratio (110), [001]β || (111), [$$1\bar {1}0$$]α established by fast electron diffraction between the ordered (β) and...     

Electrochemical Emission during the Straining and Destruction of an Aluminum–Magnesium Alloy in an Aqueous Medium

Technical Physics - The spatiotemporal structures of Portevin–Le Chatelier deformation bands at the stage of neck formation and fracture of an aluminum–magnesium alloy deformed in an...     

Influence of Chitosan on Orientation–Micellar Ordering of the Pluronic F-127 Gel Phase in an Aqueous Medium

Optics and Spectroscopy - The influence of chitosan on orientation–micellar association of Pluronic F-127 in an aqueous medium in the temperature range of 4–37°C has been studied...     

Traps in the Nanocomposite Layer of Silicon–Silicon Dioxide and Their Effect on the Luminescent Properties

Physics of the Solid State - The traps of charge carriers in thermal films of silicon dioxide and silicon dioxide with a nanocomposite layer consisting of silicon oxide and silicon nanocrystallites...     

Solid–state diffusion–controlled growth of the phases in the Au–Sn system

The solid state diffusion-controlled growth of the phases is studied for the Au–Sn system in the range of room temperature to 200 °C using bulk and electroplated diffusion couples. The number of product phases in the interdiffusion zone decreases with the decrease in annealing temperature. These phases grow with significantly high rates even at the room temperature. The growth rate of the AuSn₄ phase is observed to be higher in the case of electroplated diffusion couple because of the relatively small grains and hence high contribution of the grain boundary diffusion when compared to the bulk diffusion couple. The diffraction pattern analysis indicates the same equilibrium crystal structure of the phases in these two types of diffusion couples. The analysis in the AuSn₄ phase relating the estimated tracer diffusion coefficients with grain size, crystal structure, the homologous temperature of experiments and the concept of the sublattice diffusion mechanism in the intermetallic compounds indicate that Au diffuses mainly via the grain boundaries, whereas Sn diffuses via both the grain boundaries and the lattice.     

Excitation of strontium atom in electron–atom collisions

The excitation of ³D levels of strontium atom by slow monoenergetic electrons has been studied experimentally. Thirty six excitation cross-sections were measured at 30-eV electron energy. Optical excitation functions for most of the transitions were recorded in the 0–200-eV electron-energy range. The excitation cross-section as a function of the principal quantum number has been found to correspond to a power law for all ³D series.     

On the Reproduction of the Solar Activity Variations in the Range 2–40 Months in the Interplanetary Medium

Journal of Experimental and Theoretical Physics - We compare the quasi-biennial variations and Rieger-type variations (on a timescale of less than 1 year) in solar activity, interplanetary...     

Empirical Regularities in the Behavior of the Dissociation Excitation Cross Sections in Collisions of Electrons with Cesium–Halide Molecules

The behavior of the constants A _i. and _i that characterize the dependence of the dissociation excitation cross sections on the main quantum number of the upper energy level is analyzed for spectral series of the cesium atom in collisions of electrons with cesium–halide molecules. In addition to a similarity, some deviations from analogous regularities established previously for the halides of other alkali metals are also found.     

Guided Waves in a Multi-Layered Cylindrical Elastic Solid Medium

We investigate the guided waves in a multi-layered cylindrical elastic solid medium. The dispersion function of guided waves is usually complex and the dispersion curves of all modes are not conveniently obtained. Here we present an effective method to obtain the dispersion curves of all modes. First, the dispersion function of the guided waves is transformed into a real function. The dispersion curves are then calculated for all the modes of the guided waves by the bisection method. The modes with the orders n = 0, 1, and 2 are analysed in two- and three-layer media. The existence condition of Stoneley wave is discussed. The modes of the guided waves are also investigated in a two-layer medium, in which the velocity of shear wave in the outer layer is less than that in the inner layer.     

Superconductivity of the FeSe/SrTiO_3 Interface in View of BCS–BEC Crossover

In paired Fermi systems,strong many-body effects exhibit in the crossover regime between the Bardeen-CooperSchrieffer(BCS)and the Bose-Einstein condensation(BEC)limits.The concept of the BCS-BEC crossover,which is studied intensively in the research field of cold atoms,has been extended to condensed matters.Here by anal.yzing the typical superconductors within the BCS-BEC phase diagram,we find that FeSe-based superconductors are prone to shift their positions in the BCS-BEC crossover regime by charge doping or substrate substitution,since their Fermi energies and the superconducting gap sizes are comparable.Especiall.y at the interface of single-layer FeSe on SrTiO_3 substrate,the superconductivity is relocated closer to the crossover unitary than other doped FeSe-based materials,indicating that the pairing interaction is effectively modulated.We further show that hole-doping can drive the interfacial system into the phase with possible pre-paired electrons,demonstrating its flexible tunability within the BCS-BEC crossover regime.     

Kinetics of the Processes of the Change in the Concentration of Photosensitive Paramagnetic Centers on Excitation and De‐Excitation of ZnCdS Single Crystals

The EPR technique is used to study the behavior of photosensitive paramagnetic centers (PPC) in zinc sulfidebased single crystals under different conditions of excitation by UV radiation.     

Role of Aging in the Formation of Non-spherical Nanostructures during Laser–Matter Interaction in Water

Optics and Spectroscopy - Pulsed laser ablation of different surfaces in liquid environment has broad prospects to selectively synthesize nanoparticles (NPs) with specific optical properties, as...     

Quantum Yield of a Silicon Avalanche Photodiode in the Wavelength Range of 120–170 nm

Technical Physics - We have designed a silicon avalanche photodiode for detecting vacuum ultraviolet radiation. The external quantum yield of a silicon avalanche photodiode has been investigated in...     

Temperature and Concentration Dependences of the Landau–Placzek Ratio in Aqueous Solutions of γ-Picoline

Optics and Spectroscopy - Ratios of the intensities of the fine-structure components at molecular light scattering (Landau–Placzek ratios) have been investigated depending on the...     

Role of heterogeneities in Staebler–Wronski effect

The effect of light soaking (LS) on the properties of hydrogenated amorphous silicon (a-Si:H) presents many challenging puzzles. We look at some of them, along with their present understanding. In particular, the role of the heterogeneities in LS is examined. We find that for most of the solved as well as unsolved puzzles, the long-range potential fluctuations arising from the heterogeneities in the films, afford an alternative view which looks quite plausible. The implications of such considerations are used to speculate on the possibility of making stable a-Si:H solar cells.     

Role of Activator and Vacancy Centers in the Decay of the Gamma Scintillators of CsI–Na Crystals

The influence of the concentration of an activator (C _NaI) and of plastic deformation on a change in the contribution of a slow component to the decay of the -scintillations of CsI–Na crystals was investigated, as well as the influence of C _NaI on a change in the shape of the luminescence excitation spectrum in the region of absorption of activator centers (AC) and of vacancy-related centers (VRC) and also on a change in the intercenter time of deexcitation of the centers indicated. It is shown that AC and VRC participate in the photoluminescence and -scintillations of CsI–Na crystals. In the -scintillations, AC are responsible for the component ₁ = 370 nsec, whereas the components ₁ = 460 nsec and ₂ 2 sec are associated with VRC. The reduction of ₁ from 770 to 560 nsec with an increase in C _NaI from 2·10^–3 to 3·10^–2 mole% and from 570 to 470 nsec after plastic deformation of the crystals ( = 5%) along the 111 axis is caused by a decrease in the number of VRC. The mechanisms underlying the -scintillations of the CaI–Na crystals containing AC and VRC and also the decrease in the number of VRC are discussed.     

Computer Modelling of Metal Dissolution in the Presence of Aqueous Electrolyte

The semi-empirical Hartree-Fock intermediate neglect of differential overlap (INDO) method was used to explore the potential energy surface of adsorbed water molecules and to speculate,using fairly simple chuster models,on the reaction path followed by metal ions leaving the surface.As an example,INDO calculations were used to calculate the potential energy curve for a metal atom leaving the surface and entering into a solvation cage composed of tetrahedral arranged water molecules.The effect of adding a NaCl ion pair to the system with the halide ion above the dissolving atom was also explored.     

The Role of Interfacial Interactions in the Toughening of Precipitated Calcium Carbonate–Polypropylene Nanocomposites

This paper investigates the effect of the interphase properties and the interfacial interactions between matrix and filler on mechanical properties of precipitated calcium carbonate (PCC)–polypropylene nanocomposites. PCC particles were coated with stearic acid (SA). The weight ratio of SA on the particles (w _SA) ranged from 0 to 0.135 g SA/g PCC. The introduction of PCC particles resulted in an increase in stiffness and yield stress compared with the pristine polymeric matrix and, at the same time, it increased the impact resistance. The maximum improvement in the impact behaviour was achieved for the composites with w _SA =0.045 corresponding to the theoretical monolayer ratio. A decrease in interfacial interactions between monolayer coated PCCs and the matrix with respect to the uncoated particles was observed by using a semi-empirical equation developed by Pukànszky. The low degree of interfacial interactions between particulate filler and matrix allows a matrix–particle debonding phenomenon, as shown by scanning electron microscopy analysis. Extensive plastic deformations were evident as well, promoting an improvement in toughness. The thickness of the interphase between particles and matrix was evaluated by using the Shen–Li model which is based on the hypothesis of a non-homogeneous interphase. It results that the thickness increased in the order uncoated < monolayer coated < 3% SA coated ? 13.5% SA coated particles. The thinner and stronger interphase found for the composite with uncoated particles can be explained with the high interaction between matrix and filler and the consequent low mobility of the polymeric chains.     

Excitation of Elastic Wave of an Arbitrary Plane Source on Surface of a Multilayered Medium

We investigate the elastic waves excited by an arbitrary plane piezoelectric source on the surface of a multilayered medium. Based on the previous studies, the 2D elastic wavefield in the multilayered medium is extended to 3D space. The propagator matrix for the 3D wavefield is investigated and the displacement-stress response for the boundary conditions is obtained. The excitation and propagation of the Rayleigh and Love waves are analysed further. It is found that the propagation velocity of the Rayleigh and Love waves does not depend on the propagation azimuth θ in the plane parallel to the free surface of the multilayered medium while the displacement is strongly dependent on the azimuth θ.