The thermodynamic properties of Al-Si system melts

The thermochemical properties of Al-Si system melts were determined by an improved isoperibolic calorimetry method. The data obtained correlated with the reliable partial and integral enthalpies of mixing reported in the literature. The method developed was used to model the thermodynamic properties of melts with the use of the liquidus coordinates of the phase diagram of the Al-Si system. The modeled and experimental results were in close agreement with each other.     

Method of Decreasing the Order of a Partial Differential Equation by Reducing to Two Ordinary Differential Equations

Using additional unknown functions and additional boundary conditions in the integral method of heat balance, we obtain approximate analytic solutions to the non-stationary thermal conductivity problem for an infinite solid cylinder that allow to estimate the temperature state practically in the whole time range of the non-stationary process. The thermal conducting process is divided into two stages with respect to time. The initial problem for the partial differential equation is represented in the form of two problems, in which the integration is performed over ordinary differential equations with respect to corresponding additional unknown functions. This method allows to simplify substantially the solving process of the initial problem by reducing it to the sequential solution of two problems, in each of them additional boundary conditions are used.     

Magnetic and Elastic Vibrations in Manganese–Zinc Spinel Crystals as the Functions of Anisotropy Constant

The amplitudes of magnetic and elastic vibrations for Mn_0.61Zn_0.35Fe_2.04O₄ spinel crystalline slab are calculated by solving the equations describing the magnetic and elastic dynamics. The anisotropy constants, magnetization, second-order elastic constants and magnetoelastic coupling constants for a studied crystal are expressed as the functions of temperature. The magnetization vector and elastic shear components are found as the functions of the first magnetic anisotropy constant at different values of an external constant magnetic field greater than a saturation field. The procession patterns for normally and tangentially magnetized slabs are displayed for two values of the first anisotropy constant. High absolute values of the first anisotropy constant are shown to refer to reorientation of the magnetization vector.     

Luminescence instability of films and new organic light-emitting diodes based on zinc complexes with tetradentate Schiff bases: Influence of heating and laser irradiation

Organic light emitting diodes (OLEDs) based on zinc complexes with tetradentate Schiff bases — ZnSB [H₂SB =H₂Sal1, H₂Sal2 (derivatives of salicylic aldehyde); H₂MO1, H₂MO2 (derivatives of o-vanillin)] display reversible and irreversible electroluminescence (EL) instability. The reversible instability occurs after switching voltage on and the irreversible instability produced by UV light irradiation, heating, and aging under the ambient conditions. In view of the results obtained, the first type of instability is associated with the trap filling processes and the second type appearing at heating is possibly attributed to the changes in the interface domains. Recommendations for the evaporation and capsulation conditions are provided.     

Degradation of organic light-emitting diodes based on different-ligand complexes of terbium (III) salicylate and 2-phenoxybenzoate

Degradation (D) of organic light-emitting diodes (OLEDs) based on new different-ligand complexes of terbium salicylate (Tb(Sal)₃(TPPO)₂) and 2-phenoxybenzoate (Tb(pobz)₃(TPPO)₂) with triphenyl phosphinoxide (TPPO) was studied. Initial reversible D is associated with charge carrier trap filling. A temperature increase, applied stress relief, and short-term irradiation with UV light lead to trapped charge carrier release and electroluminescence (EL) intensity recovery. During strong heating, irreversible D is observed after the recovery; this D requires in addition an electric field (EF). Intense UV light causes D without EF. The use of ac bias voltage eliminates reversible D, and sealing retards irreversible long-term D.     

Ion Mobility in Triple Sodium Molybdates and Tungstates with a NASICON Structure

Journal of Experimental and Theoretical Physics - Research data for the diffusion mechanisms of Na+ ions in Na1 – xMg1 – xAl1 + x(XO4)3 (X = Mo, W) compounds with the NASICON-type...