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The effect of the velocity of compact metal projectiles of spherical and cylindrical shapes on the size of craters formed in steel targets of different strength was studied in the velocity range 2–10 km/s by numerical simulation using two different computational techniques. The behavior of the materials of the projectile and target is described using a model of a compressible elastoplastic medium with a constant yield strength. The projectile materials are copper, titanium, and tantalum. The projectile mass and velocity are specified assuming that their kinetic energy is constant. It is found that the dependences of the crater depth on the velocity of projectiles with constant kinetic energy have a maximum and the crater volume decreases monotonically with increasing velocity.

In this paper, we present the results of numerical simulation of explosive formation of a high-speed compact element from copper, steel, and aluminum cumulative liners combining the shape of a hemispherical segment smoothly converting into a cylindrical surface (“hemisphere–cylinder” liners). The problem is solved in a two-dimensional axisymmetric setting considering the limiting parameters of the dynamic stress-strain state causing plastic flow and destruction of the cumulative liner material. The original model of the functioning of cumulative shaped charge, which determines the effect of individual elements of the cumulative liners, including the difference in numerical characteristics of their physicomechanical properties and critical destruction conditions, on the final parameters of the high-speed compact element, was used. The plastic properties of the material and the critical conditions for its destruction were found not to affect the final velocity of the formed high-speed compact element, but they affect its shape, dimensions, and mass.

The experimental study identified the antiviral activity of Bacillus pumilus RNase (binase) against the reovirus of serotype 1/strain Lang. For the first time, it has been found that 50 μg/mL of binase effectively reduced the hemagglutinin and cytocidal activity of reovirus in Vero cell line. The preincubation of the enzyme with reovirus before infection of the cells inhibited the viral replication. To determine the stagedependent effect of reovirus reproduction upon binase inhibition, the infected cells were treated with binase or RNase A at different phases of the infectious cycle. The treatment of virus-infected cells has revealed that both enzymes have a maximal antiviral effect on the reovirus propagation during early phases of the reovirus reproduction cycle, with binase being more effective than RNase A. It has been hypothesized that the combined action of the oncolytic reovirus and binase is promising for the elimination of tumor cells carrying mutated RAS gene.

We consider the physicomathematical formulation of the problem of explosive formation of a penetrator from a low-sphericity copper lining. Calculations are made for the formation of a penetrator for a phlegmatized hexogen charge for two models of the behavior of the lining material (copper), and the results are compared with the experimental data.

A device that produces gas-discharge plasma streams with a predetermined cross-sectional shape is proposed. It contains a base and a hollow cathode attached to it, which are coaxially placed in the hollow anode. Between these electrodes, an electric-insulation layer of Teflon-4 is laid, whose thickness changes within the range λe < h < 3λe, where λe is the electron free path in a gas-discharge plasma stream. The anode is a cavity closed with a cover, which forms a U-shaped space in the anode volume. Coaxial holes of a predetermined shape were made in the anode, cathode, and insulation. The device provides a discharge current of up to 1 А, an accelerating voltage across the electrodes of 0.3–1 kV, and an energy of charged particles in a plasma stream of 10–425 eV. In this case, the plasma stream propagates beyond the borders of the electrodes to a distance of 10–140 mm.

We propose a model of the electric field distribution in the electrode system of a gas-discharge device. The possibility of application the method of conformal mapping of a function of a complex variable for describing analytically the form of the distribution of equipotential lines of the field in the region of the circular orifice in the anode of the gas discharge device is demonstrated. The method for obtaining a system of parametric equations for determining the equipotential lines and field lines is described. We obtain the theoretical maps of the electric field distribution, which make it possible to determine their relation with the electrophysical parameters of the electrode system of the device.

The physicomathematical problem of the explosive formation of a cumulative knife (jet) from a cumulative charge and its penetration into a 250-mm-thick armed concrete obstacle is considered. Numerical simulation data for a specific extended cumulative charge acting against this obstacle at different focal lengths of the charge are presented.

Mycoplasmas are incapable of de novo synthesis of nucleotides and must therefore secrete nucleases in order to replenish the pool of nucleic acid precursors. The nucleolytic activity of mycoplasmas is an important factor in their pathogenicity. Bacterial ribonucleases (RNases) may produce a broad spectrum of biological effects, including antiviral and antitumor activity. Mycoplasma RNases are therefore of interest. In the present work, the capacity of Acholeplasma laidlawii and Mycoplasma hominis for RNase synthesis and secretion was studied. During the stationary growth phase, these organisms were found to synthesize Mg2+-dependent RNases, with their highest activity detected outside the cells. Localization of A. laidlawii RNases was determined: almost 90% of the RNase activity was found to be associated with the membrane vesicles. Bioinformational analysis revealed homology between the nucleotide sequences of 14 Bacillus subtilis genes encoding the products with RNase activity and the genes of the mycoplasmas under study. Amino acid sequences of 4 A. laidlawii proteins with ribonuclease activity and the Bsn RNase were also established.

The described generator produces a wide-aperture flow of charged plasma particles (electrons, positive and negative ions) with a cross-sectional diameter of at least 120 cm, which propagates to a distance of 50 cm or more (depending on the operating mode and the geometric dimensions of the vacuum chamber). The uniform distribution of charged particles in the cross section of the plasma flow is at least 98%. The discharge current reaches 1 A or more at an accelerating voltage of 0.3–6 kV. The energy of particles in the plasma flow under such conditions was 10–6000 eV at current densities of up to 10 mA/cm2. The generator structure contains coaxially positioned meshes of the anode grid and the cathode grid. The latter closes the cavity inside the cathode volume at a depth of 3–5 mean free paths of electrons in the gas-discharge plasma flow. The cathode is manufactured so that the cavity diameter exceeds the diameter of the through cavity in the cathode insulation, the latter being determined by the size of the plasma-flow cross section. The distance between the grid anode and the cathode grid is equal to the Aston dark space of a glow discharge, thus permitting the cathode lifetime to be increased to 3 years. It is shown that the duration of the cathode continuous operation is determined by the chosen values of its cavity depth and accelerating voltage.

The formation of an out-of-electrode plasma in a high-voltage gas discharge is studied. The occurrence and self-maintenance of a gas discharge and its associated plasma fluxes on the straight portions of electrical field lines are predicted theoretically and confirmed experimentally. It is shown that the focusing of the gas discharge and plasma fluxes is provided by increasing the length of the field line straight portions toward the symmetry axis of a hole in the anode. It is found that, when the discharge power (more specifically, an accelerating voltage applied to the electrodes of the gas-discharge tube) rises, the straight portions of the field lines elongate and concentrate near the symmetry axis of the hole in the anode. Recommendations are given on using the out-of-electrode plasma in surface micro- and nanostructuring.

The possibility of fractionation of heterogeneous bacterial populations using wide-porous agarose cryogels containing grafted aliphatic groups with the chain lengths of 4, 7, and 12 carbon atoms was demonstrated for the first time. The maximum sorption of vegetative cells of gram-positive bacteria (60%) was shown for the polymeric carrier with the chain length of 4 carbon atoms, while the hypometabolic cells appearing in the population after prolonged (60-day) cultivation were trapped by wide-porous affinity sorbents with C7- and C12-aliphatic groups much better than vegetative cells.

The shock stage in the behavior of explosively loaded steel plates and cylindrical shells was studied experimentally. A three-wave structure of the shock front was observed for both plane and cylindrical samples. The split-off strength of the shell and plate materials was determined. For both loading schemes, the split-off was shown to not occur for the samples with a thickness of 1 mm. The decay of the pressure amplitude in the first shock wave was found to be appreciably stronger for the cylindrical samples than for the plane samples.

The equation of state was developed for materials subjected to the polymorphic transformation upon explosive loading with an explosive charge. The formula obtained was used in the numerical modeling of the explosive projection of plates and cylindrical shells fabricated from St 20 steel. The theoretically estimated kinematic parameters of a projected body were compared with the experimental data.

A method of measuring the surface temperature in the region exposed to a low-temperature plasma flux is suggested. The boundary-value problem of heat conduction for the unsteady case is analytically solved by means of the Laplace transformation. Analysis of the analytical relationships shows that this method measures temperature with a high accuracy in real time. Its application in formation of micro-and nanostructures in a low-temperature plasma is considered.

It has been shown that the phenotypic dissociation of Bacillus subtilis SK1 and S. typhimurium TA100 is induced by hexylresorcinol, an exogenous non-species-specific autoregulator of pleiotropic action, which is genotoxic for both pro- and eukaryotes. Nongenotoxic homoserine lactone, a chemical analogue of cell-density-responsive species-specific regulators, does not induce bacterial dissociation. The phage resistance of the S- and R-type variants of S. typhimurium TA100 induced by hexylresorcinol has been found to be the same as that of the S- and R-type salmonella variants obtained by the routine subculturing method.

It is established that when a liquid-aluminum-silicon (Al-Si) structure is bombarded with ions and electrons having energies up to 6 keV, the process of Si dissolution in the aluminum is slowed. Mechanisms are put forward for the formation of an excess concentration of atomic-size voids (“vacancies”), the formation of a vacancy flux normal to the Si surface, and entrainment of impurity atoms by this flux. It is shown experimentally that zones completely free from Si atoms, where the silicon exhibits maximum solubility, in the aluminum may be formed in the bulk of the aluminum melt. The size of these zones can easily be controlled by the parameters of the ion-electron flux.