On the joint application of cartesian and bipolar coordinates to solve boundary value problems of potential theory and elasticity theory

Equations are obtained that connect harmonic functions with separated variables in Cartesian and bipolar coordinates. These equations can be used to investigate a number of new boundary value problems of potential theory and elasticity theory for domains bounded by Cartesian and bipolar coordinate system coordinate lines.     

Sensor and microelectronic elements based on nanoscale granular systems

Specific effects observed in small metal particles due to their distinction from bulk material as well as phenomena inherent to an ensemble of these particles coupled by electron tunneling have attracted considerable attention to nanosized systems. Electron and photon emission was revealed as a power was fed into the metal nanoparticle films deposited on insulating substrates either by passage of an electrical current in the film plane or by laser irradiation in the infrared and visible range. The electrical conductivity of metal nanoparticle films close to the percolation threshold is sensitive to temperature, substrate bending and adsorption of various gases. Besides, the current–voltage characteristics of the conduction current of a system consisting of a metal nanoparticle film and an adsorbate exhibit a voltage-controlled negative resistance region. These peculiar properties enable nanosized particle systems to be used for various applications. The present review deals with a variety of sensors for physical properties and microelectronics elements based on nanoparticle films. The mechanisms underlying the special properties are discussed. Some technological methods ensuring better parameter definition and long-term stability of sensors are also described.     

Electrodeposition of hard iron-zirconia dioxide composite coatings from a methanesulfonate electrolyte

A study of electrodeposition of iron-based composite coatings containing zirconia dioxide particles from sulfate and methanesulfonate electrolytes showed that the zirconia dioxide content in the deposits obtained from the latter electrolyte can reach 10–12 wt %. Models of the process of ZrO₂ particle incorporation into an iron matrix were considered. The microhardness of the composite deposits was estimated.     

Electron photoemission in plasmonic nanoparticle arrays: analysis of collective resonances and embedding effects

We theoretically study the characteristics of photoelectron emission in plasmonic nanoparticle arrays. Nanoparticles are partially embedded in a semiconductor, forming Schottky barriers at metal/semiconductor interfaces through which photoelectrons can tunnel from the nanoparticle into the semiconductor; photodetection in the infrared range, where photon energies are below the semiconductor band gap (insufficient for band-to-band absorption in semiconductor), is therefore possible. The nanoparticles are arranged in a sparse rectangular lattice so that the wavelength of the lattice-induced Rayleigh anomalies can overlap the wavelength of the localized surface plasmon resonance of the individual particles, bringing about collective effects from the nanoparticle array. Using full-wave numerical simulations, we analyze the effects of lattice constant, embedding depth, and refractive index step between the semiconductor layer and an adjacent transparent conductive oxide layer. We show that the presence of refractive index mismatch between media surrounding the nanoparticles disrupts the formation of a narrow absorption peak associated with the Rayleigh anomaly, so the role of collective lattice effects in the formation of plasmonic resonance is diminished. We also show that 5–20 times increase of photoemission can be achieved on embedding of nanoparticles without taking into account dynamics of ballistic electrons. The results obtained can be used to increase efficiency of plasmon-based photodetectors and photovoltaic devices. The results may provide clues to designing an experiment where the contributions of surface and volume photoelectric effects to the overall photocurrent would be defined.     

Selective wetting in a hydrocarbon liquid-perfluorocarbon liquid-solid system

Selective (displacement) wetting is, for the first time, investigated in a hydrocarbon liquid-perfluorocarbon liquid-fluorinated polyethylene system. Contact angles upon the selective wetting are shown to be quite sensitive to the presence of fluorocarbon groups on the surface of the polymer, and wetting inversion takes place when the surface concentration of fluorine is increased above 10^?4 kg/m².     

Microscopic Theory of Tensosensibility of Multi‐Layer Polycrystalline Films

The microscopic theory for the coefficient of longitudinal tensosensibility of multi‐layer polycrystalline metal films has been developed. The theory takes into consideration as the scattering of conductivity electrons on external and internal surfaces of separate layers and crystalline boundaries, so as the dependence of specular reflection coefficient and coefficient of transmission of crystalline boundaries and boundaries between separate layers on deformation. The experimental verification of the theory done on three‐layer film systems Cr/Co/Cr, Cr/Cu/Cr and Ni/Co/Cr given as the quality correspondence.     

Size Effect and Processes of Interdiffusion in Multilayer Films

The electrophysical properties of multilayer structures consisting of the alternate Co and Ni layers or Co and Cr layers obtained in high vacuum (˜ 10⁻³ Pa) were investigated. The size dependences of the temperature coefficient of the resistance (TCR) of the films were obtained experimentally and then compared with the R. Dimmich theoretical model. The analysis shows that the main reason of the difference between theoretical and experimental data of TCR is the interdiffusion of atoms from one layer to another.     

Determination of the Bone Mineral Crystallite Size and Lattice Strain from Diffraction Line Broadening

Diffraction line broadening observed for the biological apatite is ascribed to small crystallite dimensions and lattice imperfections. However, it is rather difficult to separate the individual contribution of each factor. Therefore in numerous works a total inverse width of a diffraction peak is only used as a size/strain parameter. Several authors determine the bioapatite crystallite size ignoring the lattice strain. As is shown in the present paper, this problem can be resolved for oriented specimens. The crystallite size and lattice strain were calculated by two independent methods: Fourier analysis and approximation with threefold convolution of X‐ray lines. The approach proposed can be useful in the investigations into structural aspects of the bone apatite and its synthetic analogues as the crystal size is related to surface defects and the lattice strain to lattice imperfections.