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Том 475, № 1 (2017)
- Год: 2017
- Статей: 6
- URL: https://journals.rcsi.science/0012-5016/issue/view/9219
Physical Chemistry
Correlation relationships between the energy and spectroscopic parameters of complexes with F···HF hydrogen bond
Аннотация
Twenty six complexes with a F···HF hydrogen bond have been theoretically considered. Correlation relationships between the bond energy and IR and NMR parameters—the frequency shift Δν of the ν(HF) stretching vibration and the change in the proton chemical shift Δδ1Н caused by complexation—have been constructed. In the entire range of existence (energy 1–200 kJ/mol), the plots obey the power law for the optical spectrum and the linear law for the NMR spectrum.
115-118
MD simulation of the transitions between B-DNA and A-DNA in the framework of a coarse-grained model
Аннотация
Transitions between the B and A forms of a short DNA double helix (12 base pairs) at different salt concentrations in an aqueous solution have been studied by the molecular dynamics method in the framework of a coarse-grained model with explicit ions but without friction. It has been shown that the A-DNA, stable at high salt concentrations, is a dynamic conglomerate of the molecule and the ions coming from the solution into the deep major groove and then leaving it. In such a short helix, in the model without friction, even at low salt concentrations, transitions from B-DNA to A-DNA and back are frequent and fast. Stable ADNA (without transitions to B-DNA) forms at salt concentrations greater than 0.45 mol/L.
119-121
Analysis of electrochemical electron transfer mechanisms in molten salts by the frontier orbital method
Аннотация
It has been demonstrated that the application of the frontier orbital method to the quantum-chemical analysis of possible variants of electron transfer in electrochemical systems makes it possible to sharply narrow the search for the transition state and to reduce computational burden by several orders of magnitude. The high informativity of the method allows us to recommend it as a tool for verifying any hypotheses about the mechanism of charge transfer in electrochemical systems.
122-125
Kinetics of a bimolecular chemical reaction in the liquid phase with association of both reactants
Аннотация
Mathematical modeling of a bimolecular chemical reaction in the liquid phase was carried out taking account of association of both reactants. The formally simple chemical reaction is thus transformed into a multistage process, which results in the formation of temporal dissipative structures. It was found that, apart from the usual dynamic modes, there appear oscillations of the concentrations of intermediates, characterized by two considerably differing periods.
126-128
Hydrojet engine with pulse detonation combustion of liquid-fuel
Аннотация
An experimental prototype of an engine of a new type for water transport—pulse detonation hydroramjet—was designed, built, and tested for the first time. Firing test of the prototype with a 2-L combustor was performed on a specially designed test stand with a thrust-measuring frame capable of producing an approach water stream in the form of a submerged jet with a velocity up to 10 m/s. The specific impulse was experimentally measured, ranging from 370 s at high operation frequency (20 Hz) to 1200 s at low operation frequency (1 Hz); i.e., the measured specific impulse of the pulse detonation hydroramjet exceeded that of the best modern liquid rocket engines.
129-133
Effect of pressure on the structure of composite chitosan films obtained from solutions in carbonic acid
Аннотация
The effect of pressure in solutions of chitosan in carbonic acid with the AgNO3 precursor on the structure of cast nanocomposite films with silver nanoparticles has been studied for the first time. The size of silver nanoparticles can be controlled by varying pressure in carbonic acid.
134-137