Entropy of crystallization of materials from a “molten” sublattice of superionic conductors

It is shown that the entropy of crystallization of materials (such as Cu, Ag, Au, and Li) in a “molten” sublattice of superionic conductors→crystal system may substantially exceed the entropy of crystallization of the same materials from a melt. The observed behavior explains the known tendency of various superionic conductors to form filamentary crystals (whiskers) in the solid phase, together with the completely different structure of these whiskers. Fiz. Tverd. Tela (St. Petersburg) 40, 227–228 (February 1998)     

Effect of free electrons on growth of “cancers” in mixed electronic-ionic conductors

The reasons for the anomalously rapid (for solids) growth of “cancers” (filamentary crystals, hills, pores, and other formations) on the surface of samples of superionic conductors with mixed electronic-ionic conductivity (of the type Cu_2−x Se and Ag₂Te) are discussed. The effects are attributed to the acceleration of mobile ions and activated ions in the “core” of the superionic by free electrons in the joint “chemical” diffusion of ions and electrons in the samples. Pis’ma Zh. éksp. Teor. Fiz. 64, No. 2, 97–100 (25 July 1996)     

Dufour effect in superionic copper selenide

The Dufour effect has been observed in the superionic conductor copper selenide, Cu_2−x Se. This effect is the opposite of the Soret thermal diffusion effect which was previously only observed in gaseous and liquid systems. Fiz. Tverd. Tela (St. Petersburg) 40, 242–244 (February 1998)     

Increase in the efficiency of thermoelectric heaters by using inhomogeneous branches

It is found that the heating efficiency of thermoelectric heaters can be increased by 20% or more by using inhomogeneous thermoelectric branches. The performance features of such branches in thermo- electric heaters compared with those in thermoelectric power sources and thermoelectric coolers are revealed.     

Stiffness of reinforced and unreinforced Bi2Te3 single crystals

We investigate the thermodynamics of Ω- and V-shaped bending of Bi₂Te₃ single crystals. To change the shape of the bending from Ω to V, the sample is reinforced with thin steel rods, arranged perpendicular to the cleavage planes. We find that reinforcement increases the ultimate strength of the samples by more than twofold. We show that the transition Ω→V leads to a substantial change in the spectrum of energy dissipation in the straining of the sample. Some aspects of the practical application of the observed effects are considered. Zh. Tekh. Fiz. 67, 50–54 (February 1997)     

Inhibition of the growth of excrescences in mixed electronic-ionic conductors

The thermodynamic aspects of the diagnosis, prevention, and inhibition of the growth of excrescences in mixed electronic-ionic conductors are considered in the case of the representative material copper selenide. Zh. Tekh. Fiz. 68, 67–71 (November 1998)     

Comparative study of horseradish mutant forms by radioenzymology

Radioenzymology was used to study the recombinant and mutant forms of horseradish peroxidase, namely, F221W, Q176E, Q176A, S35K, E64P, E64S, S35A, and S35KQ176E. Both removal of the Trp residue and introduction of an additional one result in a simpler dose response; the insertion of polar residues stabilizes the enzyme molecule through realization of a more closed conformation. The greatest oscillation changes were found for the replacement by Ala. It was assumed that the binding site of guaiacol as a substrate is located near the residue 64, which is structurally related to the residue 176 and the heme. A scheme of formation of the intermediate through rotation of the Trp aromatic ring was proposed.