The geometrical aspect of the gauge fields and the possibility of a general description of local and nonlocal interaction in QED

It is shown that the use of analogues of the QCD gauge-invariant structures (type of “strings” and “stars”) in QED enables one to consider the generalized gauge-invariant amplitude, which satisfies the requirements of the quantum theory of gauge fields and allows one to describe electromagnetic (EM) interactions both with local and nonlocal charged matter fields beyond the scope of the Lagrange approach. This causes no negative consequences for the theory as a whole. The invariant character of the amplitude structure in relation to hierarchical evolution of the structural forces and structural elements of the nonlocal field allows its use in an unchanged form to describe EM interaction processes in different scales of matter structure. The generalized amplitude features a continuous limit in transition from nonlocal to local fields.     

Effect of supramolecular structure on the morphology of the surface of carbonized polytetrafluroethylene

The morphology of the surface of polytetrafluoroethylene (PTFE), subjected to chemical etching in a sodium naphthalene solution in tetrahydrofuran, is studied by high-resolution scanning electron microscopy. It is shown that along with the molecular defluorination processes, etching of the polytetrafluoroethylene surface leads to surface fragmentation and crack formation. The emerging microstructure of the etched surface is associated with the bulk supramolecular structure and rheological properties of the polymer. The decreasing ductility of polytetrafluoroethylene after the pressing and sintering of polymerizate particles results in an increase in the number of cracks per unit area. The orientation of fibrils under uniaxial tension and the formation of spherulites, occurring upon radiation modification, is manifested in the preferred orientation of cracks. Increasing density and decreasing porosity of PTFE significantly lower the etching rate and the depth and length of cracks.     

Effect of Thermal Treatment on the Structure and Properties of Hydroxyapatite

X-ray diffraction analysis and transmission electron microscopy were used to demonstrate that hydroxyapatite produced by the precipitation method is a powder composed of anisometric particles with longitudinal size of 70–100 nm and transverse size of 7–9 nm. The particles are constituted by crystallites with longitudinal sizes of 22–24 nm and transverse sizes of 8–10 nm. At a temperature of 600°C, the crystallite sizes grow, and the volume porosity and specific surface area decrease. Synthetic hydroxyapatite has a low thermal stability as compared with hydroxyapatite of biological origin.     

Highly selective substitutions in 2,3-dichloropyrazine. A novel general approach to aloisines

A highly efficient synthesis of the potent CDKs (cyclin-dependent kinases) inhibitors, aloisines (substituted 5H-pyrrolo[2,3-b]pyrazines) is presented. The method is based on highly selective monosubstitution of a single chlorine atom in 2,3-dichloropyrazine with lithiated ketones, esters, and nitriles followed by co-cyclization of the resulting intermediates with primary amines or hydrazines.     

Growth Rate anisotropy of the K2(S,Cr)O4 Mixed Crystals Grown from Aqueous Solution

The ratio of growth rates of the K₂(S,Cr)O₄ crystals in the [100] and [001] directions (the anisometry coefficient) is proportional to the initial effective supersaturation of the solutions from which the crystals were grown. The values of the factors of asymmetry and excess of distribution of the crystal anisometry coefficient are affected by the composition of solution. The change in the values of these factors is caused by the change in the value of the initial supersaturation of solution according to the specific features of the solubility diagram.