On the possible mechanism of increase in the phase transition temperature in a ferroelectric-insulator composite

The phase transition temperature of a small ferroelectric sample has been determined by solving the system of nonlinear equations of electrostatics and the equilibrium equation with a nonlinear boundary condition at the sample surface with the use of a method of finite elements. It has been shown that the phase transition temperature can be shifted to higher temperatures owing to the effect of the surface. The dependence of the phase transition temperature on the size and shape of the ferroelectric sample and on the properties of its surface has been found. The possibility of the experimental observation of this effect has been discussed.     

Estimation of the state of biological samples by the composition of the headspace using a multisensor system

The use of identification parameters of piezoelectric sensor array A _ij ^max for estimating the state and differentiation of the type of infectious agent by virtue of marker gases in the headspace over biological samples is discussed. A regression model for the screening diagnosis of the presence of infectious agents is developed.     

Propagation and transformation of light waves in magnetically active periodic structures

The influence of an external magnetic field applied to a magnetoactive periodic structure on the specific features of formation of the photonic band gaps is established. It is shown that abrupt (stepwise) changes in the polarization of the radiation transmitted by the periodic structure and reflected from it exist near the band gap edges. The possibility of a substantial enhancement of the Faraday effect at a low level of optical losses in the magnetoactive periodic structure with a large number of periods and a dielectric contrast and without a defect layer is substantiated.     

Enhancement of the Faraday rotation in magnetically active periodic structures with defects

Relations that determine the field of a light wave transmitted through and reflected from a periodic structure lying on a substrate and containing a defect layer are derived for the case of an arbitrary symmetry of both the defect layer and the layers forming the structure. Exact expressions are obtained for the determination of the positions of the defect modes. The feasibility of a considerable enhancement of the Faraday rotation while retaining 100% transmission through the defect-containing magnetically active structure at a high dielectric contrast is revealed. It is shown that the angle of magnetooptical rotation of the polarization plane in a periodic structure is a bounded quantity.     

Magnetoelectric Effect in a Two-Layer Ferromagnetic-Piezoelectric System

Russian Physics Journal - The theory of the direct magnetoelectric (ME) effect in a two-layer ferromagnetc-piezoelectric structure that differs from the existing theories by the exact accounting of...     

Splitting of potential curves in the two-center quantum-mechanical problem for the Dirac equation

An asymptotic (over a large internuclear distance) theory is presented for the two-center quantum-mechanical problem described by the Dirac equation. The asymptotic equation of the two-center wave function of a Dirac electron is constructed for a system consisting of an arbitrary ion and an atom. Using this function, we calculate the asymptotic leading term of the potential curve splitting in the relativistic two-center problem.Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 109, No. 2, pp. 232–249, November, 1996.     

On Anomalous Influence of an External Electric Field on a Second-Order Transition in a Thin Ferroelectric Film

Physics of the Solid State - The specific features of a phase transition in a thin ferroelectric film in an external electric film have been studied in terms of the...     

Specific features of light propagation in a periodic structure with regular arrangement of defect layers

Specific features of light propagation in a periodic structure with a large number of identical regularly arranged defect layers are considered. Rigorous analytical formulas for the transmittance and reflectance of the structures are derived. It is shown that the presence of periodically arranged inclusions may give rise to new photonic band gaps, with their positions controlled by the dielectric properties and thickness of the defect layers.     

Selection of a piezoelectric sensor array for detecting volatile organic substances in water

Sensitive coatings for piezoelectric sensors used to assess the presence of anthropogenic volatile organic substances in the equilibrium gas phase over natural water have been selected using an array of measuring elements, and the data have been processed using principal component analysis. Groups of piezoelectric sensors with similar characteristics for substance identification have been determined based on the correlation between piezoelectric sensor responses when vapors of organic substances were detected. The stepby-step optimization of the piezoelectric sensor array has been carried out in order to identify the greatest number of organic compounds (vapors) in the sample. Volatile organic compounds can be identified in their aqueous solutions and natural water using the optimized piezoelectric sensor array.