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To simulate a convulsive syndrome, phenylcarbamate was administered intraperitoneally at a dose of 1 mg/kg. Valproic acid aminoester (43 mg/kg), caramiphene (50 mg/kg), and diferidine (2 mg/kg) were investigated as potential anticonvulsant drugs. Blood and brain tissue for the determination of acetylcholinesterase (AСhE) were taken at 10, 30, 60 minutes, 6 and 24 hours after administration of the xenobiotic. In case of poisoning with reversible inhibitors of AChE and accumulation of acetylcholine in the CNS synapses (due to inhibition of AChE activity), only the initial manifestations of convulsive activity are caused, and other mechanisms not associated with AChE inhibition are responsible for the processes of further maintenance and recurrence of seizures.

The article presents the pathogenetic mechanisms of eye damage by gas self-defense weapons in detail. We discuss the mechanisms of eye damage and structural changes of the tissues after gas-trauma. The causes of these changes and the main clinical manifestations accompanying them are analyzed. We analyzed the factors, influencing the development of dystrophic changes of the ocular surface in detail. The information on various techniques for self-assistance, mutual aid and earlier specific treatment of this injury was summarized. An aqueous solution of pediphene substance promising for use is considered, which has a number of pharmacological properties that fundamentally affect the pathogenetic mechanisms of gas-weapon trauma. Its effectiveness was shown in the experiment in comparison with the control group without treatment and the group using the combined drug-dexamethasone in combination with an antibiotic.

The paper considers the construction of voltage rectifier circuits of three-phase and single-phase limited power energy sources. As a rule, such sources have an increased value of internal resistance. This circumstance leads to interference at the output of the energy source in the presence of a smoothing filter at the rectifier output. The article discusses ways to reduce the amplitudes of these interference with increasing frequency. This is achieved by forming the current consumed by the rectifier in the form of a multi-stage curve approximating a sinusoid. The schemes of three-phase and single-phase rectifiers are given.

In modern power setups of autonomous objects, electromechanical converters with good mass and volume performances are used. However, the problem of lowering the specific energy parameters of electric machines remains important. This article presents new technical solutions and calculation methods for unconventional energy-saving machines with improved mass and volume performances. The electromagnetic core of machines includes a stator winding with active and front conductors of rectangular cross section. The cross section of the jumpers for connections of active and front conductors is reduced. The front conductors of the stator winding do not intersect. These measures make it possible to reduce the consumption of copper, achieving a decrease of the length of the electromagnetic core while maintaining high efficiency. It has been shown that manufacturing such multilayer wavelike windings is promising. The design of the an induction motor with a stator winding of this type has been considered. The technical features in designing electrical machines with a new stator winding are discussed. A detailed end-face scheme of the stator winding and a scheme of the sequence of conductor commutation of this winding are presented. Expressions for calculating the overhang parts of the winding are given. Results of comparison new and serial motors with a power of 75 kW are given.

The factors of increased wear of current-carrying brushes in direct-current motors designed for high-altitude operation are considered. The results of testing six motors with different degrees of airtightness are presented. It is found out that increased airtightness makes the lacquer film less resistive (thinner) and increases the brush wear. A method of decreasing the wear of current-carrying brushes at standard and high altitudes is proposed that consists in installing a DMS-140 molybdenum disulfide lubricating brush. The lubricating brush is installed in an auxiliary brush holder or in a pocket structurally connected with the current-carrying brush holder on the header runway. The effect of the collector profile material (copper, cadmium bronze, chromium bronze) on the wear of current-carrying brushes is studied, as well as the efficiency of installing lubricating brushes for standard and high-altitude operations. The effect of lubricating brushes on the performance of a 5-W motor is considered as well as the results of testing seven 5-W motors equipped with lubricating brushes in conformity with the machine and warranty service specifications. Information is given on the results of long-term storage (for 1 and 1.9 years) of four motors with different capacities equipped with lubricating brushes, as well as in thermal vacuum tests of 10-W motors under p = 10–5–10–6 mm Hg.

The article presents the results from studying the eccentricity in permanent magnet synchronous machines having different numbers of slots per pole and phase (q). The advantages and drawbacks of using winding arrangements with different values of qareshown. An expression describing the physical processes of interaction between spatial induction harmonic components in the air gap under eccentricity conditionsisanalyticallyobtained. The electromagnetic torque pulsations arising with different kinds of eccentricity—static, dynamic, and mixed—are determined with the aid of field models and using the Maxwell magnetic tension forces. Differences between the obtained characteristics are pointed out. Aprocedurefor calculating the electromagnetic torque pulsations in the no-load and on-load operation modes using the Femm finite-element computer program is presented. Recommendations on selecting the qvalue for reducing the negative effect of different eccentricity kinds aregiven.

The construction of new disk induction motors of block-module type, which are a part of motor-transformer units (MTUs), are considered. The induction motors are intended for operation in hermetic objects under extreme conditions: a gas, steam-to-gas, and liquid environment at high pressures (up to 150MPa) and temperature (up to +600°C). The primary winding of the transformer part of the unit is connected to a three-phase network, and the secondary z-phase bar winding is located in Z grooves of the magnetic conductor of a transformer closed on one side by a short-circuited ring. The motor part of the unit contains an induction motor with a short-circuited rotor and stator with bar uninsulated winding connected to the transformer secondary winding; on the opposite side, it is closed by a short-circuited ring. The induction motor can be implemented with a disk short-circuited rotor located between two disk stators with bar windings. The bars of the transformer secondary winding are connected with Z bar-shaped hermetic lead-ins installed in a hermetic partition. Each bar-shaped hermetic lead-in is connected at the other end with n bars of the stator winding through intermediate conductive arc-shaped segments adjoining the stator. The operating principle and operation features of new disk induction motors of block-module type are considered.

Regardless of the conditions, the condensation of 4-amino-2,4-dihydro-3H-1,2,4-triazole-3-thiones with aromatic aldehydes afforded the corresponding hydrazones as the only product. Both initial amines and resulting hydrazones exist as the thione rather than thiol tautomer. In no case bicyclic 5,6-dihydro[1,2,4]triazolo[3,4-b][1,3,4]thiadiazoles that are isomeric to the hydrazones were detected. DFT quantum chemical calculations at the B3LYP/6-31+g(d,p) level of theory with full geometry optimization showed that the hydrazone structure in methanol and DMF is more stable than the bicyclic isomer by 19–23 kcal/mol, which completely excluded the possibility for such cyclization. The thione tautomer of the hydrazones is more stable than the thiol structure by 11–13 kcal/mol.

The basic technical parameters of a series of energy-efficient asynchronous motors are presented. The primary competitive advantages of the 7AVE series are indicated. The main modifications and specialized variants produced based on it are listed. It is noted that modern designs are more efficient (in comparable energy efficiency classes) than the previously produced AIR and 5A series. The definition of the term “service factor” is clarified. The problems of choosing the rational outer diameter of stator cores are discussed. The advantages of CENELEC matching for implementing the highest classes of energy efficiency of low- and medium-power asynchronous motors are noted. The issue of the potential to design asynchronous motors of an ultrahigh energy efficiency class (IE4) is touched upon. The calculated parameters of a motor type with the IE4 efficiency class are presented.

Alkylation of 1,3-dihydro-2Н-benzimidazole-2-thione (2-mercaptobenzimidazole) with bromoethane and chloroacetic acid derivatives occurrs at the sulfur atom, leading to the corresponding 2-sulfanylbenz-imidazole derivatives. Aminomethylation of 1,3-dihydro-2Н-benzimidazole-2-thione with piperidine and 4-methylpiperidine gives reaction products at both nitrogen atoms, while reaction with morpholine gives derivative at only one nitrogen atom, which is in an equilibrium with the starting compound and bis-adduct in DMSO solution.

The products of the one-pot, three-component synthesis of [1,3]thiazolo-[4,3-b][1, 3, 4]thiadiazoles from aromatic aldehydes, thioglycolic acid, and compounds containing a C(=S)–N–NH2 fragment (thiosemicarbazide or 4-amino-2,4-dihydro-3H-1,2,4-triazole-3-thiones) are not condensed hetero-cycles (as reported by several researchers), but are thiosemicarbazones or triazolylimines of the aldehydes used.

The article presents ways to improve reliability of agricultural semiconductor frequency converters. It is shown that an increase in reliability of semiconductor converters can be achieved increasing the power reserve. At the same time, if the economic indicator is chosen as an optimization criterion, the coefficient of failure-free operation reaches no more than 0.8. In the event that resulting coefficient of failure-free operation is allowed according to operating conditions, selected criterion can be successfully applied at design stage of semiconductor converters.

In the article schemes of power circuits of a feed of synchronous reluctance machines are considered. The features of the choice of the most rational scheme by the criterion of improved weight and size parameters are shown. It is shown that the specific parameters of electric drives have values that exceed similar synchronous electric drives by approximately 20%. Improvement of specific parameters in the agriculture electric drive can be achieved not only due to the complexity of the electric machine construction, but also due to the choice of optimal schemes of power circuits. So, in agriculture electric drives with individual sources with rectangular current form, the values of overloads corresponding to electric drives with complex (compound) rotor design.

The influence of the number of winding parallel branches, steel sheets thickness in the magnetic system and the size of air gap on the overvoltage in the induction motor operating from power-width modulation converters is investigated. The mathematical model and the results of simulation of the wave processes that take place in the multiturn mush winding of a squirrel-cage motor are presented.

The list of author’s affiliations should read as follows: a Samara State Technical University, Samara, 443100 Russia b National Research University Moscow Power Engineering Institute, Moscow, 111250 Russia

The effect of lubricating brushes made on the basis of molybdenum disulfide on the decrease in the wear of current-conducting brushes in commutator machines is considered. The reason for the enhanced wear of brushes in tight and not hermetically sealed electrical machines operating at high altitudes is found. The dependence of the efficiency of the wear reduction on the amount of lubricant fed to the contact zone and the temperature in the contact zone is found.

A calculation procedure for wavelength constants and interturn overvoltages in a multiturn random winding of an induction motor supplied from a frequency converter is described. A mathematical model and modeling results for wave processes in sections (turns) of the multiturn random winding of the induction motor with a cage rotor are presented.

Pyridinium dichloromethylides, generated from substituted pyridines and dichlorocarbene, react endo-stereoselectively with dimethyl maleate to give substituted 3,3-dichloro-1,2,3,8a-tetrahydroindolizine-1,2-dicarboxylic acid dimethyl esters; the latter compounds are readily dehydrochlorinated and dehydrogenated to give the corresponding indolizine derivatives. Reaction of 3-substituted pyridines with dichlorocarbene and dimethyl maleate leads predominantly to the formation of 8-substituted indolizines. Cycloaddition of 4-picolinium dichloromethylide to unsymmetrical dipolarophiles occurs regioselectively. The observed selectivity in these reactions is consistent with predictions made on the basis of PMO theory.

Pyridinium dichloromethylides, generated from substituted pyridines and dichlorocarbene, react endo-stereoselectively with dimethyl maleate to give substituted 3,3-dichloro-1,2,3,8a-tetrahydroindolizine-1,2-dicarboxylic acid dimethyl esters; the latter compounds are readily dehydrochlorinated and dehydrogenated to give the corresponding indolizine derivatives. Reaction of 3-substituted pyridines with dichlorocarbene and dimethyl maleate leads predominantly to the formation of 8-substituted indolizines. Cycloaddition of 4-picolinium dichloromethylide to unsymmetrical dipolarophiles occurs regioselectively. The observed selectivity in these reactions is consistent with predictions made on the basis of PMO theory.

The interaction of dichlorocarbene with imines and ketene imines was studied by means of the MNDO method. The results indicate that the lack of ylide cyclization products in the reactions of dichlorocarbene with ketene imines is due to a high reactivity of ketene imine ylides in intermolecular reactions, rather than stereoelectronic factors preventing cyclization. It was shown that the dichlorocarbene reaction with N-benzylideneaniline resulting in gem-dichloraziridine proceeds through transient formation of ylide.