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Abstract Penetration of a heating pulse of quasistationary electromagnetic field into plasma in constant magnetic field directed along its surface was studied. Weakening of electron heat transfer across the magnetic field leads to more efficient heating of electrons near the plasma surface. As a result, the penetration of the field into the plasma decreases, which is accompanied by suppression of the “inverse” skin effect. Inhomogeneous heating of electrons across the magnetic field leads to generation of an electric field strength component orthogonal to both the magnetic field and the direction of temperature gradient. Appearance of the additional field strength component leads to a change in polarization of the reflected pulse. In a sufficiently strong magnetic field, due to suppression of the electron heat flux and less significant effect of the magnetic field on the ion heat flux, a state with large difference of electron and ion temperatures occurs.

We establish the conditions under which collisions of electrons with ions affect the generation of terahertz radiation at normal incidence of a laser pulse on a dense plasma in a constant magnetic field. If during the time of exposure to the laser pulse, the number of collisions of electrons occurred is not small, then the amplitude of generated magnetic field decreases, the shape of the generated pulse changes, and the total energy of terahertz radiation decreases. The influence of collisions on the generation of terahertz radiation manifests itself in a relatively weak magnetic field, when the electron cyclotron frequency is lower than the plasma frequency.

The generation of terahertz (THz) radiation under the effect of a femtosecond laser pulse on a transparent semibounded plasma in a constant magnetic field is studied. It is shown how the generation patterns of THz radiation depend on the laser pulse duration and the ratio between the cyclotron and plasma frequencies of electrons. In each of the modes considered, the total energy per unit area, spectral composition, and pulse shape of the generated THz radiation are found. It has been established that optimal generation conditions are realized at laser pulse duration comparable to the reciprocal frequency of plasma oscillations and at electron cyclotron frequency lower than plasma frequency. When cyclotron frequency exceeds plasma frequency, the possibility of increasing the generation frequency up to frequencies comparable to the cyclotron frequency is revealed.

The features of distribution are studied and a complex technology for the separation of samarium, europium, and gadolinium is proposed. This technology involves the initial isolation of 70–80% of the europium concentrate by extraction with organophosphorus acids, which makes it relatively easy to obtain pure compounds of samarium and gadolinium in subsequent operations. At the last stage, europium is isolated by chemical reduction and the captured samarium and gadolinium are returned to the beginning of the process. The content of the main substance in the resulting oxides is 99.9–99.99 wt %.

The aim of the study was to study the timing and frequency of community — acquired pneumonia in HIV-infected people, depending on the level of immunodeficiency and viral load.Materials and methods. Based on the materials of the Perm regional center for the fight and prevention of AIDS and infectious diseases, medical documentation was studied for 396 patients with HIV-associated pneumonia who died in 2014–2018 the frequency of community-acquired pneumonia (EAP) was estimated depending on the level of immunodeficiency and viral load.Results and discussion. It turned out that in most cases, EAP in relation to HIV infection is a secondary disease. The average duration of EAP after HIV infection was 4,6±3,7 years. With increasing immunodeficiency and viral load, the incidence of VP increases. Most often, VP is registered with CD4+ lymphocytes less than 200 cells/μl and viral load of 10 000–100 000 copies/ml.

The paper presents an analysis of the terms “energy efficiency” and “energy conservation” in relation to oil production. The consumption of fuel and energy resources of an oil and gas company is increasing from year to year, and taking into account the growth of tariffs for energy resources, the introduction of energy-efficient technologies is one of the urgent problems of production.

Objective. The aim of the study was to investigate the tuberculocidal efficacy of disinfectants according to the manufacturers instructions and the results of experimental studies using a test strain of Mycobacterium terrae. Materials and methods. The instructions for 150 disinfectants (DS) were studied. An experimental evaluation of the tuberculocidal efficacy of 6 DS was carried out using the reference strain M. terrae. Results. A study of the documentation for the DS showed that from the number of DS produced before 2010, only 38.2 % of the drugs were recertified after 2010. Of these, only in 50.0 % of cases it was noted in the instructions that the recertification was carried out using the test microorganism M. terrae. From the number of DS produced after 2010, only 49.2 % of the drugs were certified using the M. terrae test strain. According to the results of laboratory assessment of DS, it was shown that drugs that did not pass re-certification using M. terrae have low tuberculocidal efficacy. Conclusions. It has been established that many manufacturers of DS during certification and recertification of drugs do not test the modes of their tuberculocidal efficacy on the regulated microorganism M. terrae. In the course of laboratory assessment of the tuberculocidal effect of DS, it was confirmed that the least effective drug was the one that did not pass re-certification using M. terrae.

The removal of water from natural gas is one of the most effective methods widely used in pretreatment processes of the extracted fluid, necessary to prevent industrial problems such as corrosion and hydrate formation. In this article, the methods of natural gas drying are considered, the greatest attention is paid to absorption drying and modern innovations of this method, as the most common in the world practice.

The etiology of community-acquired pneumoniae (CAP) was evaluated according to the results of molecular-genetic and bacteriological researches of nasopharyngeal aspirate from 405 patients. According to molecular genetic studies, S. pneumoniae and M. pneumoniae are most frequently isolated from patients with CAP, and more often in children than in adults. Associations of microorganisms have been identified, among which S. pneumoniae occupies a leading position. According to bacteriological studies, S. pneumoniae is frequently isolated from patients with CAP, although the bacteriological method is not very effective.

The synthesis of a series of triesters based on 1,3,5-adamantanetriol and 7-ethyl-1,3,5-adamantanetriol and C4–C6 aliphatic acids is executed, and their physicochemical and thermo-oxidative properties are studied. The properties of the obtained esters are compared to those of pentaerythritol esters. The synthesized esters have pour points below −40°C, the range of viscosities at 100°C varies from 4.361 to 9.912 mm2/s, and the values of the indices of thermo-oxidative stability are 221.6–240.3°C.

We reveal the possibility of a low-frequency radiation generation at a normal incidence of the laser pulse on a dense plasma in a constant magnetic field. The generation occurs due to the motion of electrons under the magnetic field effect and a ponderomotive force slowly varying with time localized in the skin layer where the laser radiation penetrates. The characteristic radiation frequencies are determined by the inverse duration of the laser pulse. We find the field strength of the radiation generated and its dependences on the Larmor frequency of electrons and the plasma and laser pulse parameters.

A description of almost all the current widely used methods used for the interpretation of the results obtained in analyzing gases dissolved in oil (AGDO) is presented. In addition, a new method for identifying defect types, an algorithm for its application, and the advantages thereof over other methods are described. A technique for testing the reliability of the AGDO interpretation methods and results obtained upon testing these methods are presented. The quality of the detection provided by the considered methods has been compared with respect to various types of defects. In the course of the testing, special attention was paid to examining the issue that different methods of AGDO interpretation can identify different number of defect types. The evaluation of the quality of the methods and the testing of their reliability have been performed for a test sample containing 134 cases of transformer damage. For each case, there is a detailed description of the defect development process (the results of analyzing and testing of a transformer for the preceding period and the records in the operational documentation), as well as the results of transformer investigation, in the course of which the cause of damage done to it has been established. © 2019, Allerton Press, Inc.

A three-component one-pot procedure to synthesize 2,4-disubstituted b-fused 3,4-dihydro-2H-thiopyran derivatives by the Diels—Alder reaction of the in situ generated α,β-enethiones with maleic acid derivatives was developed. The reactivity of different unsaturated thioketones as dienes and maleic acid derivatives as dienophiles under the developed reaction conditions was studied.

For a semibounded plasma in a constant magnetic field and interacting with short laser pulse, a kinetic equation is derived, which makes it possible to describe the low-frequency movements of electrons. In the linear approximation in laser radiation intensity the solution of kinetic equation is obtained taking into account mirror reflection of electrons by the plasma surface. Using this solution, we derived low-frequency currents generated by low-frequency field and ponderomotive force that changes during the pulse affect. Under the assumption that characteristic spatial scales of changes in the low-frequency field and ponderomotive force exceed the Larmor radius of electrons, we studied low-frequency currents near the plasma surface. If the electron cyclotron frequency exceeds the inverse pulse duration, then low-frequency currents differ from their values in a homogeneous plasma only at a distance from the surface not exceeding several Larmor radii. Taking this fact into account, a solution to the equation for low-frequency field in the plasma was obtained. The terahertz (THz) magnetic field generated by nonlinear currents is found. It is shown that the maximum value of the generated field is attained at cyclotron frequency comparable with the product of the plasma frequency square and laser pulse duration.

Synthesis of 5,7-dimethyl-3-hydroxymethyl-1-adamantanol with limited conformational mobility and of a series of esters based thereon has been performed. The physicochemical properties and thermo-oxidative stability of synthesized diesters have been studied.

A series of diesters on the basis of 5,7-dimethyl-1,3-adamantanediol and 5,7-dimethyl-1,3- bis(hydroxymethyl)adamantane and C3–C10 aliphatic acids have been synthesized and their physicochemical and thermo-oxidative properties have been studied. The properties of the esters obtained have been compared to those of trimethylolpropane and neopentyl glycol esters.

A technique of lubricant modification using graphene is presented. The experimental results of the determination of the tribological characteristics inherent in the modified lubricant show that, when 0.1% of multilayered graphene is added to the complex calcium lubricant, the diameter of the wear spot exhibits a 50% decrease, the scuffing index shows a 2.9-fold increase, and the carrying capacity increases 3.8 times.

A series of triesters of 3,5-bis(carboxymethyl)-1-adamantanecarboxylic acid have been synthesized and their physicochemical and thermo-oxidative properties have been studied. The properties of the obtained triesters have been compared to those of trioctyl trimellitate, which is used as a plasticizer and a component of various lubricating materials.

Prospects for using furfural derivatives as octane boosters for gasoline are discussed on the basis of analysis of their physicochemical and operation properties. Knock resistance data, toxicity parameters, and results of motor bench tests are considered for furan compounds, furfural ethers, furfurylamine, and other furfural derivatives.

Dependences of the effective penetration depth of probe pulse field in current-carrying plasma with time-dependent temperatures of particles are determined. It is shown that the field penetration in fully and weakly ionized plasmas takes place in the subdiffusion and superdiffusion regimes, respectively.

A reaction of 5-O-succinoylavermectin B1 with alkylating agents, namely phenacyl halides, bromoacetanilides, and benzyl bromides, was studied. Esters of 5-O-succinoylavermectin B1 were obtained for the first time, which are of interest as potential antiparasitic agents.

New ivermectin-4″,5-diyl[bis(N-methylcarbamate)] was synthesized by the MoO2Cl2(DMF)2-catalyzed reaction of ivermectin with methyl isocyanate. The synthesized compound could find application as antiparasitic agent.

2-(4H-1,3-Benzoxazin-4-on-2-yl)-4,5,6-trichloro-1,3-tropolone, structural properties of which were studied using 1H NMR, IR-spectroscopy, mass spectrometry, and quantum chemistry has been obtained for the first time using an acid-catalyzed condensation reaction of 3,4,5,6-tetrachloro-1,2-benzoquinone with 2-methyl-4H-3,1-benzoxazin-4-one. It has been shown that the new tropolone possesses antibacterial activity against hospital-acquired strains of gram-negative (Escherichia coli, Salmonella enterica sv. Enteritidis, Acinetobacter baumannii, and Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus) bacteria. The obtained substance is suggested for development of a new antibacterial drug.

The results of dental examination 1000 people (370 men and 630 women) aged 40 to 89 years, who were divided into three groups: middle age - from 40 to 59 years; Seniors - from 60 to 74 years; senile - from 75 to 89 years. They have assessed the prevalence of diseases of the temporomandibular joint and masticatory muscles studied symptoms and the intensity of the flow of these diseases. Based on the clinical data improved methods for evaluating the degree of severity of the disease and the effectiveness of treatment of temporomandibular joint and masticatory muscles, methods of registration of sound phenomena in the pathology of the temporomandibular joint, and developed techniques to identify groups at risk among adults in relation to the studied pathology.

Two procedures have been proposed for the synthesis of pure (E)- and (Z)-3-(5-aryl-1,3,4-oxadiazol-2-yl)acrylic acids, by one-step cyclization of (Z)-4-(2-aroylhydrazinyl)-4-oxobut-2-enoic acids or via initial cyclization of (Z)-4-(2-aroylhydrazinyl)-4-oxobut-2-enoic acids to 5-(aroylhydrazinylidene)furan-2(5H)-ones which are then converted into the target compounds.

A process for preparing 3-substituted 3,4-dihydroquinoxalin-2(1H)-ones is proposed. It is based on the reaction of o-phenylenediamine with amides, di- and mono-esters of maleic acid as well as (E)-3-(5-phenyl-1,3,4-oxadiazol-2-yl)acrylic acid in the presence of N,N′-carbonyl-diimidazole.

Specific features of the interaction of a relatively weak electromagnetic pulse with a nonisothermal current-carrying plasma in which the electron drift velocity is much higher than the ion-acoustic velocity, but lower than the electron thermal velocity, are studied. If the state of the plasma with ion-acoustic turbulence does not change during the pulse action, the field penetrates into the plasma in the ordinary diffusion regime, but the diffusion coefficient in this case is inversely proportional to the anomalous conductivity. If, during the pulse action, the particle temperatures and the current-driving field change due to turbulent heating, the field penetrates into the plasma in the subdiffusion regime. It is shown how the presence of subdiffusion can be detected by measuring the reflected field.

New pyrazoles; 1,2,4-triazoles; β- and γ-glycols; amidrazones; and amines of the adamantane series have been synthesized. Their activity with respect to smallpox vaccine virus has been studied. High anti-smallpox activity was observed for ethyl-3-(1-adamantyl)-5-(4-methylphenyl)-1H-pyrazole-4-carboxylate (VI) and 1,4-bis(1-adamantyl)-1,4-butanediol (XII).

In the field of two-dimensionally localized pump wave, the dependences of the threshold of various modes of stimulated scattering on the scattering angle were determined for various medium parameters and pump intensities.

Design of mathematical, metrological, technical and algorithmic maintenance for construction of the universal measuring module which functions on the basis of use of a principle of time representation of the measuring information is executed. The conducted researches have shown the validity of the developed module not only for construction of new gauges but also for modernization of out-of-date measuring devices and systems. Module use allows raising essentially accuracy of measurements and noise stability with simultaneous reduction of power consumption.

A study is made of the characteristic features of the reflection and absorption of a monochromatic wave by a plasma with axisymmetric ion acoustic turbulence over a broad frequency range. The absorption anisotropy and the related conversion of an incident, linearly polarized wave into a reflected, elliptically polarized wave are described. The absorption coefficient and the difference in the phase shifts occurring in the reflection of different field components are obtained as explicit functions of the turbulent plasma parameters.

Fibre materials manufactured with modern, environmentally clean, solution-free, meltblown technology are convenient and economical polymer filters. The method of manufacturing fibre materials for such filters can be introduced in polymer processing plants interested in implementing progressive technology and expanding the line of polymer fibres and commercial articles manufactured from them.

Reflection and absorption of a linearly polarized wave by a plasma with developed ion-acoustic turbulence is studied. The dependences of the absorption coefficient and Stokes parameters of the reflected elliptically polarized wave on the anisotropic effective frequency of electron collisions are established.

It is shown that a change in the ion composition of a nonisothermal plasma is accompanied by nontrivial changes in the effective penetration depth of a strong quasi-stationary electromagnetic field generating ion-acoustic instability.

A kinetic description is developed for stimulated Brillouin scattering (SBS) in a dusty plasma with negatively charged dust grains. The threshold for SBS and the width of its spectral line are determined in the limits of weak and strong damping of the dust ion acoustic waves involved into the scattering process. For different mechanisms of the dissipation of dust ion acoustic waves, the threshold for SBS and the width of its spectral line are obtained as functions of the dust grain charge and the dust number density.

The third harmonic generation in plasma ionised by a high-power pump field is theoretically studied. The dependences of the harmonic generation efficiency on the electric pump-field strength and polarisation are found. It is assumed that the observation of the maximum of generation efficiency at the nonzero pump-field ellipticity is the universal property of the harmonic generation. This effect is nonlinear and has a threshold.

The dependence of the SBS linewidth in a carbon-hydrogen plasma on the plasma parameters and the pump field intensity is studied. It is shown that the threshold and spectral composition of SBS can be varied by changing the concentration of carbon and the degree of nonisothermicity of the plasma. The physical nature of these variations is associated with variations in the attenuation and spectrum of the ion-sound waves whose pumping leads to the development of parametric instability.

New phenomena in which the stimulated Brillouin scattering (SBS) changes the number and magnitude of frequency shifts in a plasma upon a nonlinear increase in the pumping field intensity are discovered. It is found that the SBS becomes forbidden and then allowed again (upon a subsequent increase in the pumping intensity).