Subject of Research. The paper presents the study of fluorescence enhancement of semiconductor nanocrystals and organic dyes using plasmon resonances. The study is interesting from both basic and applied science point of view. Among recent articles devoted to this topic, the one by Egorushina, et al. was high-profile, and described the case of fluorescence enhancement during nonresonant interaction of molecules and metallic nanoparticles, which is an unusual and poorly studied phenomenon. We made an attempt to perform a similar experimental study for quantum dots. Method. Samples of metallic nanoparticles with plasmon resonances in the visible spectrum region were fabricated using deposition of silver vapor in a high-vacuum chamber. The equivalent layer thickness was 5 nm, the lateral size of the islands was 30–50 nm. CdSe/ZnS semiconductor nanocrystals with a luminescence maximum at a wavelength of 630 nm and CdSe/ZnS nanocrystals with a gradient composition of the ZnS shell and a luminescence maximum at a wavelength of 520 nm were synthesized through the “hot injection” protocol. Solutions of quantum dots were deposited on island films by a spin-coating method. The absorption of the samples was measured on SF-56 spectrophotometer. Fluorescence was measured using RF-5301PC spectrofluorimeter. The luminescence decay kinetics of the samples was also studied. Main Results. As a result, luminescence enhancement during resonant interaction of quantum dots and quenching of luminescence during nonresonant interaction were obtained. The luminescence lifetime decrease characteristic of the Purcell effect was observed in both cases. Practical Relevance. Metal nanoparticles as the resonator will increase the fluorescence quantum yield of various quantum emitters by the Purcell effect.

The paper presents theoretical study of an electromagnetic wave propagation in a planar total internal reflection waveguide with a centrally located quantum well. The calculation is based on transfer matrix method application that gives the possibility to describe the propagation of light in layered structures and calculate the reflection spectrum having related it with the eigenmodes of the system. The prediction is made that the interaction appears between the excitons of the quantum well and the electromagnetic wave in the form of the anticrossing in the reflection spectrum. This behavior is a characteristic feature of such quasiparticles as exciton-polaritons. It is predicted that the value of the Rabi splitting is about several millielectronvolts for exciton-polaritons in the total internal reflection waveguide with a GaAs quantum well. It is also shown that the interaction between the excitons of the quantum well and TE and TM polarized electromagnetic waves is different that can be seen in the reflection spectrum of the structure and agrees with the optical selection rules. As a result, the alternative exciton-polariton system is proposed, which in return can be used in the modern semiconductor industry as a system for information transfer.

The paper presents detection method for one of the most common diseases. Diabetes mellitus is a group of metabolic disorders in which blood sugar level rises over a long period. Type II diabetes begins with insulin resistance, a condition when cells do not respond properly to insulin. Type II diabetes accounts for about 90 % of all diagnosed diabetes cases. Therefore, the development of new methods for diagnosing is relevant. We applied the method of IR-spectroscopy combined with multivariate analysis for blood serum analysis. The research is based on serum samples from 44 patients with diabetes and an observational group of 30 healthy donors. Cluster analysis, projection on latent structures, principal component analysis is used to differentiate groups of healthy donors and patients with diabetes. Each of the three presented methods gives the best results when the first derivative of the spectra is considered in the whole range of the spectrum. Cluster analysis, according to the procedure performed, gives the sensitivity of 100% and the specificity of 95.8 % for the considered sample. Principal Component Analysis provides a visual separation of the sample into groups of healthy donors and patients with diabetes mellitus. When analyzing this sample, using the procedure, the sensitivity was 100 % and the specificity of the analysis was 96.6 %.

Compact multirotor unmanned aerial vehicles are used to solve a variety of problems, from aerial photography to reconnaissance and goods delivery, but at present, their widespread use is constrained by the imperfection of stabilization and navigation systems. The problem can be solved by methods of neurocontrol, which are known to be an essential tool when nonlinear behavior of the craft should be taken into account. A new approach for creation of a multirotor aircraft control system is considered based on a hybrid parallel neurocontroller that uses an artificial neural network of radial basis functions. Parallel neurocontrol provides for the simultaneous use of both the conventional proportional-integral-derivative controller and the neurocontroller in the control loop, their outputs being combined. In order to optimize the calculations performed during the second layer of the neurocontroller network training, a piecewise linear function of N segments, symmetric about zero, was chosen as the function for activating the neurons of the second layer. A low-cost method is proposed for parameter optimization of the activation functions of the hidden layer neurons. It allows for network training in real time. The proposed hybrid parallel neurocontroller is implemented and studied based on an artificial neural network of radial basis functions. Bench tests have shown that the stabilization of the three axes of the hybrid neurocontroller provides quality control better than a conventional manually tuned proportional-integral-derivative controller, namely, reducing the transition time, lower amplitude oscillations in the stabilization of the unmanned aerial vehicle and increase the stability of the craft to external influences. The use of hybrid parallel neurocontroller will help to solve the problems of maneuvering and stabilization of the craft for the transition to the local navigation problem solution.

We consider the motion of a mechanical system with several degrees of freedom near zero of the phase space of states under conditions of constantly acting small perturbations. The generalized forces are represented in the dynamic equations by homogeneous forms of the first and the third degree with respect to the phase coordinates and by small time functions characterizing the constantly acting perturbations. It is assumed that there are no multiple eigenvalues of the matrix of the system linear part. For a definitely positive quadratic Lyapunov function, we define a differential inequality with Riccati differential comparison equation, together with an exponential differential inequality that is integrable in quadratures. When solving Riccati quadratic differential inequality, we assume one particular solution of Riccati equation to be known. As a result of integrating in quadratures of the exponential differential inequalities, the estimate of transient processes in the finite domain of the phase coordinates is obtained.

The article is devoted to spectral and luminescent properties of glasses of 98MgCaSrBaYAl2F14-2Ва(PO3)2 composition with ErF3 content 0; 0.1; 0.5 and 1.0 mol.%. Samples of glasses were prepared by high-temperature synthesis in an argon atmosphere. It was found that the matrix of fluoroaluminate glass, has a wide spectral transparency range from 0.2 to 6.7 μm, which indicates the great practical importance of the glassy composition under study as a material for optoelectronics devices. From the infrared transmittance spectra, absorption bands were identified, due to the presence of hydroxyl and phosphate groups, the maxima of which are about 3.0 and 4.7 μm, respectively. It has been established that the fluoroaluminate glassy matrix has a relatively low content of impurities of OH groups. For the samples doped with erbium upon excitation with a wavelength of 487 nm the luminescence spectra were obtained in the spectral range 500–900 nm. The nature of these bands is explained on the basis of a simplified energy diagram of erbium ion in a glassy matrix. Analysis of the concentration dependences of the integral intensities of the luminescence bands was also carried out, in the course of which it was found that a sample containing 0.1 mol. % ErF3 has the maximum efficiency. The 2H11/2→4I15/2 radiative transition was found to be the one mostly exposed to concentration quenching.

Subject of Research.The paper presents results of study on a thermoelectric cooling module with damping heat and electrically conductive material for cold junctions. Telluride obtained by synthesis in a melting furnace is used as a thermoelectric element material. The size of a thermoelectric element is 2.0×2.0×1.5 mm. The modules were mounted on ceramic plates made of 96% Al2O3 with dimensions of 30×30×0.89 mm. Copper coated with a layer of nickel is used as the switching bus material. Modules were attached to the board by soldering. Tin and bismuth solder paste (melting point is equal to 139°С) was used as an assembly solder alloy. An electrically conductive EX-A302L silicone with specific resistance of 0.02 Ohm/cm, densityof 3.7 g/cm3 and thermal conductivity of 2.1 W/(m·K) was used for the damping compound. Methods. For efficiency increase of a thermal contact of a thermoelectric module, associated with large temperature gradient between hot and cold energy, especially for electrical n-elements, it is recommended to use an elastic electrically conductive adhesive. Elastic conductive adhesive based on silicone is proposed. Conductive silicone EX-A302L adhesive sealant consisted of single-component cold-vulcanized silicone with splashes of conductive microgranules. Working temperature from -50 to +120°C allows for the application of this adhesive both for conventional refrigeration modules, and for the cold junction of medium-temperature modules. A phased module assembly technology is developed. Main Results. Comparative tests are carried out for the experimental thermoelectric module and the standard industrial module of TB-31-2.0-1.5 thermoelectric module at measuring installations manufactured by Kryotherm company. The integrity of the modules was tested on Testo thermal imager. It is established that the difference between the working characteristics of experimental and industrial modules does not exceed 10% and lies within the permissible limits. It is found out that destruction dynamics of the modules after temperature cycling is virtually the same. Practical Relevance. The results obtained demonstrate the application possibility of electrically conductive adhesive as a contact layer for a thermoelement. The proposed technology will allow for replacing the materials of thermoelectric module branches with more efficient ones, but having different coefficients of temperature expansion, thereby increasing the efficiency of the thermoelectric device.

Subject of Research.The paper presents the study of the effect of the most stable ionic forms of the fourth period Periodic table transition metals with different concentrations on the vital activity of Еscherichia coli. Method. The research was carried out using a complex microbiotest system, which provides for instrumental recording of changes in the intensity of elastic light scattering at 520 nm(Iod), optical density at 300 nm (Auv), pH and the redox potential (E)of samples containing initially the same number of viable test microorganisms incubated in the presence and absence of various concentrations of the test substances during the predetermined time, at given temperature and in liquid nutrient medium of defined composition. Main Results. It is shown, that the most stable ionic forms of the fourth period transition metals can be arranged in the following row according to the decrement of their antimicrobial activity: Cu2+ > Ni2+ > Mn2+ > Cr3+ > Co2+ > Fe3+ > Zn2+. We have carried out a study of fine dynamics of the vital activity of test microorganisms in the presence of the mentioned metal ions. The study has demonstrated, that the maximum growth rate of E.coli (characterized by ΔIod/Δτvalues) in all cases was reached earlier than the maximum rate of change in the metabolic activity of these microorganisms (characterized by ΔE/Δτvalues), and also that in the initial incubation period ΔE/Δτchanged non-monotonically with time as a result of E.coli life activity (it probably has reflected the metabolic processes of E.coli adaptation to the presence of excess metal ions in the test medium). Practical Relevance. The results of this study can be applied in the development of various methods for assessment of the environment ecological state, as well as regulation of the vital activity of microorganisms involved in various biotechnological processes (as producers, biodegradants of various products and materials, etc.), causing various infectious diseases, being part of the beneficial microflora of various water bodies, soils and multicellular living organisms.

We have studied efficiency of chemical mechanical method for surface polishing of nonlinear optical materials based on aminopyridine series and 4-nitrophenol. Isopropanol (C3H8O) and butanol (C4H9OH) were the solvents utilized for polishing of researched co-crystals. The experiments have shown that transmission coefficients increase after chemical mechanical polishing. The proposed method application provides minimization of surface defects of co-crystals.

Subject of Research. The methods are proposed for input control of the float-type gyro rotors, which are part of more than two hundred inertial navigation systems currently being in operation. The reliability of these systems depends directly on the reliability of the rotors. The deterioration in the quality of materials supplied and the increased frequency of technological discipline violations in recent years have led to an increase in the number of gyro corrupted during their production, associated with the jamming of the gyro-motor.Method. The developed methods of the rotor input control is based on the determination of the Al-Ni alloy composition for float-type gyro rotors, its homogeneity by the basic chemical elements and the evaluation of the surface quality of the rotors. The developed methods are based on the scanning electron microscopy application and electron probe microanalysesfor obtaining initial data and further processing by single-factor analysis of variance to determine the homogeneity of the composition. Main Results. As a result of the research, the variance of the alloy chemical composition of the researched rotors was revealed by basic and alloying elements, the surface topology of samples manufactured using the same technology was differentiated, impurity elements with dimensions from several micrometers and radically different chemical composition from the total alloy composition were determined. Practical Relevance. The developed method made it possible to identify the probable causes of the rotor descent caused by the non-compliance of the alloy chemical composition with technical requirements, the presence of undesirable impurities and inclusions, non-homogeneity of the alloy composition and micro-defects of the rotor surface.

An analytical review of the digital facial anthropometry application in the scientific and practical problems of the contemporary human world is presented. The research includes a brief history of anthropometry emergence (as a descriptive and comparative science, the subject of which is human) and its transformation into contemporary computer methods of digital anthropometry. We have considered the application features of digital facial anthropometry. They are: the concepts of the morphotype and phenotype of the face, problems of morphology and morphometry, as the basic means of digital facial anthropometry, methods of quantitative and qualitative assessment of the characteristics and parameters of individuals, the task of finding associations between gene sets in the genome and human facial features, the task of assessing the attractiveness and beauty of individuals, the relationship of facial anthropometry with "Chernoff Faces" and cognitive computer graphics used in practical medicine, the phenomenon of the human face and the problem of determining the emotions, sex and psycho-type of a person, special cases of face image recognition tasks, methods for solving them within the framework of digital facial anthropometry and examples of their solution. We have determined the prognosis for the close connection of digital facial anthropometry and the “Internet of things” in the contemporary world.

A model of multi-level organization for data storage system is studied, based on the sequential application of algorithms for vertical file distribution by the levels of data storage system, horizontal placement in sections of a certain level, and dynamic placement as a result of data migration. Selection and normalization of metadata specifying the characteristics of the stored files were performed. The model of multi-level data storage provides the storage of files in accordance with their characteristics and meets the requirements for guaranteed storage time. Representation of the storage system in the form of a matrix enables the usage of Kohonen neural network tool to arrange files by levels and sections of a specific storage system level. The application of Kohonen neural network provides the transfer from sequential execution of algorithms to placement in one step. We have proposed the model of multi-level data storage. Algorithms have been developed for file placement in a multi-level data storage system. Test examples are given which demonstrate the ability of Kohonen neural network apparatus as a tool for solving the file allocation problem in accordance with the required parameters. The combined use of file allocation algorithms gives the possibility to organize multi-level data storage in accordance with the files characteristics and the assurance of time requirements for guaranteed storage.

The paper deals with development and analysis of particular case in a complex protection for a channel where radio messages are exchanged on the basis of mutually orthogonal signal broadband characters and alphabets based on them. The object of study is a method of secure broadband channel organization using orthogonal noise-like signal symbols. The signal broadband symbols have been synthesized in the frequency domain based on pseudo-random sequences with the subsequent orthogonalization by the Gram-Schmidt method of transformation into pre-defined spectral components of the signal symbols and subsequent transformation into the time domain with the aid of the inverse fast Fourier transform. We have proposed to deploy and explore the complex secrecy approach comprising information, structural and energy secrecies. Information secrecy is brought into action with a single use of symbols retrieved out of a certain set of alphabets. Structural secrecy is reached by deployment of signal messages filtering in the area of signal symbols merge that makes difficult to determine the duration of individual signal symbols and message separation in individual signal symbols. Therefore, the decoding of entire message becomes more difficult. Energy secrecy is ensured by hiding the radio signal in the radio noise. We have carried out modeling and analysis of information, structural and energy secrecy. Practical importance of the work lies in increasing the level of protection for broadband communication channels based of the method we proposed.  The conclusions have been set up in final part of the paper.

The paper deals with the process of rational selection of a work performer for development and implementation tasks on IT projects with corporate information systems of military-industrial and civil enterprises. The subject of this work is the development of methods, algorithms and software for collecting and analyzing statistical data about available work performers for certain tasks in behalf of the further decision support for a project manager. For the purpose of analyzing and processing data about developers and other employees we use information from RedMine project management system, as one of the most popular and common tool. Based on the information collected from the RedMine database for each available performer, a vector criterion is constructed. It becomes the basis for the project manager to estimate one’s suitability for the next task based on his own preference function, some versions of which are considered in this work. The scientific significance of this study lies in the fact that this approach can be applied in a multi-agent model for the process of development and implementation of information systems, which serves for optimal planning and control in the project management activities. Practical relevance consists in automatic performance of the person responsible for the distribution of tasks among the performers via formalized mathematical approach that provides a rational loading plan for available employees that leads to economic benefit.

Criteria of text conformity to scientific style were studied. We present the research of repetition rate of keywords and phrases in a text document, percentage ratio of stop words to the total number of words in the text, deviation of the words frequency graph in the text from the ideal Zipf’s chart. The study was carried out involving executable script that checks the text according to several criteria. As a result of an experimental study on a sample of 2500 articles published in HAC/RSCI sources, the distributions of criteria values were obtained and were checked for normality by several criteria, as well as for correlation between them. Based on these data analysis, threshold criteria values were obtained and mathematically substantiated, and then were used on a test sample consisting of the undergraduate works of students in St. Petersburg Electrotechnical University “LETI”, a pseudoscientific article “Rooter: A Methodology for the Typical Unification of Access Points and Redundancy”, technical articles from the Habr Internet IT community, "Capital" by Karl Marx and a number of other texts not related to the scientific style. A necessary but not sufficient condition for the compliance of the article to the scientific style was formulated.

Subject of Research. The paper presents research of state-of-the-art methods of real-time hardware / software systems development based on FPGAs and SoCs. High-level synthesis system based on the hybrid reconfigurable NISC/TTA microarchitecture is proposed. Method. The work is based on analysis and synthesis of computer architectures and their design methods within Model-Driven Engineering, High-Level Synthesis and Hardware/Software Codesign methodologies. Main Results. Analysis of academic and commercial tools for development of hardware/software systems based on FPGAs and SoCs is performed. The key factors are determined limiting the wide introduction of high-level synthesis tools in industry. The ideology and architecture of the high-level synthesis system are developed on the basis of the original reconfigurable NISC/TTA microarchitecture. The prototype of the considered EDA system is developed. The synthesis tool and the synthesis process control interface are among the most valuable outcomes and give the possibility to explore the results of synthesis decisions made by the tool, and control the process either manually or automatically. The visualization interface of the target computational process is implemented that allows for effective representation of its multi-level organization. The end-to-end testing system is developed enabling verification of compliance between a synthesized system and its functional model. Practical Relevance. The tools implemented as part of the CAD prototype have made the synthesis process transparent and manageable for the designer and demonstrated the possibility of finding compromise design solutions in semi-automatic mode. We managed to control flexibly heuristics in the synthesizer operation, not only reducing design iterations, but also making the process convergent in principle, which is not provided by alternative technologies in many cases. NISC/TTA microarchitecture played an important role in this process. Solution of a number of test problems has shown that this design platform can be recommended for implementation of control algorithms in real-time systems and for the application in system dynamics modeling.

The paper deals with upper extremity prostheses control methods analysis. We consider prostheses control peculiarities for three main levels of amputation (prostheses for hand and fingers amputation, forearm amputation or forearm disarticulation, shoulder amputation or shoulder disarticulation). It is shown how amputation level is connected with used prosthesis control methods. The most perspective control methods for hand and fingers prostheses are the ones with extended feedback and adaptivity. It is beneficial to use neurointerfaces and muscle synergy phenomenon in control methods for forearm prostheses. Non-invasive and intuitive control methods are considered to be the most effective for shoulder prostheses. In spite of a great variety of modern technological achievements, the question of full recovery for all upper extremity functions remains open. A number of still unsolved problems, concerning the development of upper extremity prostheses control systems, is outlined: organization of extended “human – prosthesis”feedback, an effective control of multiple degrees of freedom, and simultaneous usage of the useful signal sources of different origins.

Subject of Research. The paper proposes a method and an algorithm for reducing the signal noise from an ultrasonic sensor of module detecting obstacles for people with visual disabilities. Through vibrations the sensor notifies a person of objects that are stationary or moving in front of him at low speed. Method. The proposed algorithm contains a median digital filter. The filter gives the possibility to eliminate random fluctuations of the sensor output signal owing to the fact that non-informative objects and the intrinsic noise of the devices come in view. The proposed device enables the person to abandon the sound detectors (headphones) and transmit information about the environment through a vibration motor, attached to the person’s forearm. Main Results. A mock-up of functional device is designed and manufactured. Ultrasonic HC-SR04 sensor is applied in the item mock-up. For the signal processing, the “Arduino Nano” board was used. The proposed algorithm is programmed on the board using the MatLab software package. By the known method parameters were calculated that ensure the operability of the ultrasonic sensor for various environmental parameters. The results of ultrasonic sensor signal processing by digital filters are presented. It is shown that the standard deviation of the measured parameters (distance) is reduced by more than twice. The results of the sensor signal processing of the item mock-up in the laboratory for stationary objects and objects with low linear velocity (up to 1 m/s) are presented. Practical Relevance. The device being developed contributes to improved navigation accuracy for the movement of people with visual disabilities.

We consider the problem of image classification by deep learning methods for solving classification task for primary morphological elements of skin lesions. The quality of medical care provided to the population depends largely on the medical personnel competence. The problem of medical errors is quite acute in various medical fields, especially, in dermatovenerology. In view of these conditions, the creation of clinical decision support systems becomes one of the promising directions of improving the quality of medical care for patients with dermatovenerological profile. A module of automatic detection of primary morphological elements of skin lesions on skin lesions images can be considered as one of the components of such systems. This study proposes a solution for the problem of primary morphological elements classification based on deep learning and transfer learning. We compare the effect of different learning algorithms application on the accuracy of resulting skin lesion images classifier. We provide experimental results on application of suggested solution to the following primary morphological elements: pustule, macule, nodule, papule and plaque. The proposed algorithm showed 76.00% accuracy for 5 classes of primary morphological elements (pustule, macule, nodule, papule and plaque), 77.50% accuracy for 4 classes (macule, nodule, papule and plaque) and 81.67% accuracy for 3 classes (nodule, papule and plaque).

The paper considers the rank behavior of the matrix leading coefficient of transfer function numerator of a sampled multidimensional linear time-invariant system when the sampling period tends to zero. Zero order hold sampling method is used. It is shown that the rank of the coefficient under consideration for all sufficiently small values of the sampling period is maximal if the natural condition of nonsingularity of the initial continuous prototype system is satisfied. In particular, if the dimensions of the system input and output coincide, then sampled system with a nonsingular leading coefficient is generated with any sufficiently small sampling period. This feature plays an important role in solving many problems of control theory. For example, the classical criterion of decouplability of linear systems requires the nonsingularity of the system interactor, and for systems with a nonsingular leading coefficient, this condition is satisfied automatically. In the following,while the synthesis of minimax regulators for general form discrete systems, the artificial reduction of the system to the form with the maximal rank of the leading coefficient is one of the first steps in an optimal regulator design.  The results of this work have proved that this step is superfluous if a discrete system under control is a result of sampling of a nonsingular system, as is often the case. The results of the work are illustrated by the example of an induction motor discrete model.

The paper presents a new method of identifying the parameters of the ship model using symmetric motions. The subject of research is the improvement of the parameter identification accuracy under the condition of complete uncertainty of mathematical models of the ship hull and reaction wheel device, as well as the development of a new position reference sensor for ship models in the form of a tautwire inclinometer. Small symmetric reversing accelerating-decelerating program motions about roll angle were used, while the model of the vessel was fixed in the test basin and the movement in other degrees of freedom was excluded. To create the programmed motions, an electric motor with a flywheel mounted on the vessel was used. The control system has been developed as an application of a hybrid adaptive controller consisting of a consecutive compensator and a sliding controller, and their parameters are adjusted taking into account the restriction on their maximum values. A new approach involves carrying out two experiments. During the main experiment, the program motions of the model occur about the roll angle, while the additional experiment involves programmed motions of the flywheel around the flywheel rotation angle. The program trajectory of the flywheel was obtained according to the results of the main experiment. Illustrative results are given showing the essence of the proposed method and the results of the control system with harmonic oscillation as a reference trajectory. The operating principle of the cable inclinometer is considered, and a brief overview of the existing technical solutions is presented concerning the part of the structure for the desired cable tension support. Calculation formulas are given determining the position of a vessel with a dynamic positioning system in the case of measuring angles in the cable inclinometer using potentiometers or accelerometers. The results can be useful when carrying out model tests or for full-scale vessels with dynamic positioning systems.

Subject of Research.The paper considers the factors for reducing the pulsations of the electromagnetic torque in a precision instrumental electric drive with sinusoidal pulse-width modulation based on a permanent magnet synchronous motor. It is demonstrated that the estimation of electromagnetic torque pulsations cannot be based only on the spectral characteristics of the phase voltage or current. Method. The method is based on the consideration of sinusoidal pulse-width modulation as a particular case of space-vector modulation. The proposed method provides for estimation of the electromagnetic torque pulsations by the full hodograph of the stator current vector. Main Results. The electric drive simulation results in the environment of MatLab/Simulink are presented. It is shown that a change in the load, modulation algorithm or phase shift of the sweep signal results in a significant change in the pulsations of the electromagnetic motor torque and requires the study of the effect of these factors during optimization of instrumental drive characteristics with an AC motor. The attention is drawn to the phenomenon of low-frequency modulation of electromagnetic torque pulsations brought about by the interaction of interharmonics, that is, harmonics with frequency higher than the frequency of the main harmonic, but not multiple of it. It is shown that the cause of interharmonic in electric drive with pulse-width modulation is the lack of synchronization of the modulation frequency and sweep. Practical Relevance. The results of the work can find application in the design of precision electric drives.

The paper deals with the application of spectrophotometric method and the sensor for determination of contaminating hydrocarbon impurity presence in waste water. The sensor is designed on the basis of modern element base. For measurement accuracy increase it has computer processing of analysis results for the absorption spectra of liquid (water) media in the ultraviolet wavelength range. The proposed sensor and computer program enabled the study of hydrocarbon impurity presence in the water that is an important factor for continuous monitoring of the environment. The absorption spectra of gasoline, diesel fuel, synthetic motor oil, fuel oil, natural oil are given as the most frequently present as impurities in the water, measured on an automated spectrophotometric sensor model. The use of modern small-sized elements makes it possible to design a small-sized highly sensitive sensor for express analysis of the water quality.

This paper is devoted to recording of a periodic lattice in the photopolymerized nanocomposite with nanoparticles of nonlinear optical DAST crystal (4-dimethylamino-N-methyl-4-stilbazolium tosylate) by holographic method. Nanocomposite consists of the mixture of two monomers: IDA (Isodecyl acrylate) and TMP (Trimethylolpropane ethoxylate (1 EO/OH) methyl ether diacrylate) with molecules of DAST dissolved in methanol. Initiator In2 (2,2-Dimethoxy-2-phenylacetophenone) provides photopolymerization.At solution centrifugal separation solvent evaporation and crystal formation start. It is shown that there is a record of the volume hologram when two-beam interference is used. Micro photos prove the movement of DAST nanoparticles in volume that provides creation of nonlinear grating, which can be used for quasi-phase matching of nonlinear effects.

The fluorescence effect of the scandium compounds with 2-naphthoyltrifluoroacetone  on solvent composition was studied. The earlier unknown increase in fluorescence quantum yield of scandium diketonate was observed under the change of solvent from dimethylformamide to water. The increase in quantum yield of fluorescence was interpreted as the consequence of scandium compounds aggregation into nanoparticles in water environment.

The paper presents the results of Relacy Race Detector (RRD) library research as applied to the problem of multithreaded code testing. The study revealed several shortcomings of the RRD library. They are: a static number of threads, complex project structure, errors in implementation and lack of support for snapshots. The work has corrected the shortcomings described above and presented a new approach for the atomic snapshot of multiple threads using fork and fiber mechanisms. With the application of these results and implemented changes it is now easier to use the RRD library for multithreaded applications testing.