卷 42, 编号 5 (2023)

The thermal stability of N-allyl derivatives 7H-difurazanofuroxanoazepine and 7H-trifurazanoazepine in the nonisothermal and isothermal modes is studied. The formal kinetic patterns of decay and the temperature dependences of the reaction rate constants are determined. The thermal stability of allyl and amine derivatives of azepines is compared.

7-Cyanomethyl-7Н-difurazano[3,4-b:3′,4′-f]furoxano[3″,4″-d]azepine (Az(O)CH2CN) and 7-cyanomethyl-7Н-trifurazano[3,4-b:3′,4′-d:3″,4″-f]azepine (AzCH2CN) are synthesized for the first time as potential dispersants of solid fuels for gas generator engines; their molecular structure, enthalpies of combustion, and formation are determined; and the relative aircraft flight range is estimated when using Az(O)CH2CN and AzCH2CN as fuel dispersants.

In this study, molecular modeling is used to study the interaction of the autoregulatory factor of bacteria, a chemical analog of the inducers of anabiosis of 4-hexylresorcinol (4HR), with the outer and inner membranes, the porin protein, peptidoglycan, DNA, and the DNA stabilizing protein Dps of the Escherichia coli (E. coli) bacterium. The concentration dependence and molecular mechanisms of the interaction of 4HR with cell polymers are studied by molecular dynamics in the full-atomic approximation. The spatial and energy characteristics of 4HR complexes with various cellular components are obtained. Using principal component analysis, the characteristics of DNA and the DNA-binding Dps protein are determined under conditions of various 4HR complexes. The obtained results, which are consistent with the experimental data, allow a deeper understanding of the processes that occur during the protection of the bacterial cell at the level of the envelope and the preservation of DNA by nucleoid proteins.

The properties of a specially created analytical model of conformational rearrangements of a Gaussian macromolecular chain adsorbed on the surface of a metal nanoparticle in an external electric field are investigated. The results of calculations based on this model of the structure of polyelectrolyte chains and molecular dynamics (MD) modeling of polypeptide conformations near a gold nanoparticle are presented. It is found that an increase in the strength of the external electric field leads to a displacement of the links of the macromolecular edge to one of the poles of the polarized nanoparticle.

Blends based on isotactic polypropylene (PP) and synthesized ultrahigh molecular weight polydecenes (PDs) with different molecular weights are obtained. Their structure, thermophysical, deformation, and rheological properties are studied. It is shown that the differences in the molecular structure of PDs are the main factor determining the phase structure of the studied blends. The addition of PD changes the thermophysical and deformation properties of PP. Nuclear magnetic resonance (NMR) studies have shown that polymeric materials become more fusible and the structure of amorphous regions changes with an increase in the content of PD. The molecular characteristics, viscosity, and quantitative content of PD determine the rheological behavior of the studied blends.

Indium oxide is synthesized hydrothermally from an aqueous or alcoholic solution of indium nitrate. The phase composition and structure of the synthesized samples, as well as their conductivity and sensory response during the detection of hydrogen, are studied. A change in the conditions of hydrothermal synthesis leads to the formation of a metastable rhombohedral phase together with the main cubic phase of indium oxide. It is shown that an increase in the concentration of the rhombohedral phase in indium oxide leads to an increase in its conductivity and the maximum sensor activity for hydrogen.

In this paper, the basic principles of the creation of a virtual positron annihilation lifetime spectrometer are considered. The possibility of using such a virtual measuring instrument to verify the data on the size distribution of micropores obtained based on the actually measured annihilation characteristics in systems with a highly developed free volume is discussed.