Strong amplification of an electric field and electro-optical response in ultrathin heterostructures ferroelectric-linear dielectric

An electroded heterostructure consisting of a dye layer sandwiched between two polymer ferroelectric layers is discussed. The dye layer plays a role of the probe of the electric field measured by an electroabsorption technique. Using this new method the electric field in ferroelectric and dielectric layers can be measured separately. When an a.c. voltage is applied to the heterostructure, the electric field in the dye layer increases 2.2 times (up to 0.55 GV/m), whereas the field in the ferroelectric decreases 2 times with respect to the average field in the entire structure. Moreover, the dye layer sandwiched between the ferroelectric layers may stand without breakdown the fields 5–7 times higher than a neat reference dye layer confined between metal electrodes. Therefore, the performance of electro-optical, electromechanical and other field controlled devices may be improved considerably when their functional materials are placed between ferroelectrics layers.     

Application of the theory of algebraic systems for creating a hierarchy of solid structures formed under equilibrium and nonequilibrium conditions

A unified hierarchy is proposed for molecular and solid structures formed under equilibrium (ideal crystals) or nonequilibrium conditions (real crystals, fractally ordered crystalline, quasicrystalline, and amorphous solids, as well as composite solid materials that are aperiodic on an atomic-molecular level but are periodic on a macroscopic level). The construction of this hierarchy is based on applying the theory of algebraic systems (groups, rings, and fields) to the multiplication of an initial structure in space depending on an inflation coefficient (numbers) expressed in the general form . Examples are presented of molecular and polymer structures described by groups or rings, fractally ordered solids whose structures are described by fields, and solids with damped or self oscillations in their composition, whose structures are described by fields or periodic rings of fields with complex spatial multiplication factors. Fiz. Tverd. Tela (St. Petersburg) 41, 799–804 (May 1999)     

Equations for translational relaxation in a steady supersonic jet of a mixture of monoatomic gases

On the basis of the Boltzmann kinetic equation with the use of the ellipsoidal distribution function a system of equations that takes the two-dimensional flow near a nozzle into account was derived for the parameters of a supersonic steady jet expanding into a vacuum.     

Analysis and monitoring of the stressed state in solids by gas sensors

Gas release from solids under mechanical stressing of specimens up to failure was studied. The amount of hydrogen being released vs. strain developed in a specimen under step-by-step loading was measured. The hydrogen evolved in strained metals (iron, nickel, copper, aluminum, etc.) and some epoxy-resin-based composites was detected by chemical sensors in a gas atmosphere at normal atmospheric pressure. The amount of hydrogen was shown to grow with the amount of plastic strain and peak upon failure. A method for strain analysis in solids was worked out. It was applied to analyze the stressed state of the rotor material of a centrifuge during its operation.     

Dynamics of liquid crystal azimuthal anchoring at a poly(vinyl cinnamate) interface measured in situ during polarized UV light irradiation

An automated in situ technique for the measurement of the director reorientation at a nematic-aligning photosensitive polymer interface during polarized UV light irradiation has been developed. Using this technique, the photoinduced azimuthal anchoring energy (~20 merg cm -2 ) and the adsorption part of the latter (~7 merg cm -2 ) have been evaluated for the E7-poly(vinyl cinnamate) system. The kinetics of the director reorientation have been shown to be a very slow process (~1 h) and probably controlled by adsorption-desorption of liquid crystal molecules at the interface.     

Question of the complexation of tetrachlorostannane with benzyl chloride

Conclusion The condensation of PhCH₂Cl with the liberation of HCl catalyzed by SnCl₄, occurs in the PhCH₂Cl-SnCl₄. system. The proposal of the existence of a cis-octahedral complex, 2PhCH₂Cl· SnCl₄, was proved erroneous.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2336–2337, October, 1987.     

Probing shear-band initiation in metallic glasses

In?situ acoustic emission monitoring is shown to capture the initiation of shear bands in metallic glasses. A model picture is inferred from stick-slip flow in granular media such that the origin of acoustic emission is attributed to a mechanism of structural dilatation. By employing a quantitative approach, the critical volume change associated with shear-band initiation in a metallic glass is estimated to be a few percent only. This result agrees with typical values of excess free volume found in the supercooled liquid regime near the glass transition temperature.