Omsk State Technical University

Organic compounds have the widest practical application, and the methodology of their synthesis is often developed specifically to solve applied problems in medicinal chemistry, catalysis, materials chemistry, agriculture, food industry, and the creation of electronic and sensor devices. This is due to the huge variety of properties and functional capabilities of organic substances, as well as the ability to fine-tune their structure to impart certain practically useful characteristics. Currently, the number of organic compounds used in various fields of industry, medicine, and agriculture is in the hundreds of thousands, and their number continues to grow steadily due to the rapid development of synthetic organic chemistry and predictive methods for determining properties, including using artificial intelligence. This collective review is devoted to the achievements of Russian chemists in the field of practically oriented organic chemistry over the past 5–10 years. The review presents the achievements of leading research teams representing both RAS institutes and Russian universities, from Kaliningrad to Siberia.

Considered operating processes and integral characteristics of piston long-stroke low-speed compressor stages when using various process gases as the working fluid. The study examined two design variants of a long-stroke, low-speed compressor stage: a basic version with a standard arrangement of self-acting valves in the working chamber, and a modernized version, which incorporates the advantages of known technologies for increasing the delivery efficiency, including selection of the main dimensions and parameters of the stage; changes in the dimensions and design of the valves, changes in the design of the cylinder–piston seal; and changes in the arrangement of the suction valve in the working chamber. The indicated efficiency, delivery coefficient, and discharge temperature are considered as integral indicators. Thermodynamic and thermophysical properties of the working gas, its state parameters at the suction, discharge pressure, main dimensions, and stage parameters were used as independent parameters. A comparative analysis of the efficiency of the working process of the stage under consideration was carried out in the range of medium and high pressures using gases with significantly different molecular weights as the working fluid. For the gases under consideration, a comparative assessment of the delivery coefficient, indicated efficiency, and discharge temperature was carried out in the considered range of discharge pressures for the basic and modernized stage designs. The presented results reflect the competitive capabilities of the stage in question in comparison with existing industrial analogues, including in terms of their weight and dimensions.

Electron microscopy and electron probe microanalysis are used to estimate the distribution of carbon atoms in cementite particles and defective substructure elements at distances up to 10 mm from the running surface along the central axis and the symmetry axis of the gage corner of differentially quenched long 100-meter rails after a passed gross tonnage of 1411 and 1770 mln t. Three mechanisms of cementite plate transformation have been analyzed. Extremely long-term rail operation is shown to be accompanied by a significant redistribution of carbon atoms in the surface layers up to 10 mm thick. In the initial state, the main amount of carbon atoms concentrates in cementite particles; after extremely long-term rail operation, carbon is also located on structure defects (dislocations, grain and subgrain boundaries), in the surface layer, and in the α-iron-based lattice. An increase in the passed tonnage from 1411 to 1770 mln t is accompanied by more noticeable motion of carbon atoms to structure defects in the gage corner compared to the running surface. The results are discussed using the concepts of bifurcation interstitial structural states in crystal lattice rotation zones and the mechanism of plastic distortion, as well as an analogy between extremely long-term operation and megaplastic deformation.

We identify a class of left-invariant pseudo-Riemannian metrics on Lie groups for which the Laplace-Beltrami equation reduces to a first-order PDE and admits exact solutions. The defining condition is the existence of a commutative ideal 𝔥 in the Lie algebra 𝔤 whose orthogonal complement satisfies 𝔥^⊥⊆𝔥. Using the noncommutative integration method based on the orbit method and generalized Fourier transforms, we reduce the Laplace–Beltrami equation to a first-order linear PDE, which can then be integrated explicitly. The symmetry of the reduced equation gives rise, via the inverse transform, to nonlocal symmetry operators for the original equation. These operators are generically integro-differential, contrasting with the polynomial symmetries appearing in previously studied classes. The method is illustrated by two examples: the Heisenberg group H_3(ℝ) with a Lorentzian metric and a four-dimensional non-unimodular group with a metric of signature (2,2). In the latter, classical separation of variables is not directly applicable, yet the noncommutative approach yields explicit solutions and reveals the predicted nonlocal symmetry.

The investigation concerns carbon fiber–reinforced composites with a PTFE matrix, focusing on the effects of filler content and technological processing modes on mechanical, tribological, and supramolecular properties. An approach to composite fabrication is proposed, involving preliminary chemical functionalization of carbon fibers in an acidic medium (a mixture of sulfuric and hydrochloric acid solutions) to enhance interfacial adhesion. It is shown that functionalization increases tensile strength by up to 48