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The temperature stability of the laser wavelength is an important characteristic of a laser Doppler anemometer with chromatic channel separation. In this work, experimental studies of the wavelength shift of a semiconductor laser diode by 660 nm as a function of temperature and laser radiation power are carried out. It is established that the temperature drift of the wavelength lies within 0.2 nm/°C. It is shown that the use of semiconductor diodes of this type in laser Doppler anemometers with chromatic channel separation is possible, but requires careful selection of optical filters.

To date, two basic types of algorithms for self-calibration of optical angular encoders have been developed in precision goniometry, differing in regular and irregular localization of the reading heads used in their structure. The analysis of the precision values of such encoders revealed the presence of special features not provided for by the theory, which stimulated the execution of experiments on modeling the expected values of such algorithms. The simulation model of optical angular encoders proposed by the authors of the article based on a two-dimensional data array makes it possible to identify the methodological error of the measurement algorithm used with sufficient accuracy for practice by determining the residual contribution of the distorting function to the final measurement error. In addition, it allows us to identify the characteristic features of calibration curves formed on the basis of methods with uniform or nonuniform localization of the reading heads. The simulation results show that self-calibration methods based on regular localization of the reading heads allow for higher measurement accuracy compared to methods based on the use of irregular localization.

On the base of a physico-mathematical model of ion exchange and field-assisted ion migration in glasses, with the use of a beam propagation method and mode analysis, simulations with subsequent fabrication of photonic integrated circuits in K-8 domestic optical glass operating at a wavelength of 1550 nm, have been performed. The main passive waveguide components, including single-mode waveguide dividers of optical signals, directional couplers, polarization converters, etc., have been fabricated and studied. Multichannel waveguide splitters of optical beams and matrices (512 × 512 pcs) of long-focal plane-convex microlenses for Shack-Hartmann wavefront sensors have been created by the method of field-assisted ion migration in glass substrates.

A method for determining the modulation transfer function (MTF) of infrared (IR) objectives is proposed. With the help of an objective under test, the image of a narrow exit slit of a monochromator used as a radiation source and tuned to a certain wavelength is focused in the form of a long narrow strip onto a cold metal screen with a fine aperture slit. Such a slit aperture, used instead of a pinhole aperture, allowed us to increase the useful signal and employ the exit slit of the monochromator as a radiation source. Behind the screen, instead of a small-area IR detector previously used in similar characterization studies of IR objectives, an apertured 2D IR FPA detector was used. With the help of 320×256 mid-wave IR (MWIR) and long-wave IR (LWIR) focal-plane-array detectors based on epitaxially grown mercury-cadmium-tellurium films, the Line Spread Function and MTF of MWIR and LWIR objectives were measured. The experimental data obtained were compared to the calculated diffraction-limited MTF of the tested objectives.

Experimental setups of a two-channel wavefront sensor (WFS) based on moiré deflectometry have been proposed and developed in recent years. The capabilities of this WFS have been tested in the atmospheric turbulence measurements. Like other WFSs, it can be used in various areas. Therefore, we have developed a MATLAB graphical user interface program to allow any user to easily make use it. This program takes simultaneous horizontal and vertical moiré patterns as input data and reconstructs the corresponding wavefront map and its aberration values. The algorithm of the process is explained step by step in this paper. For a typical input moiré pattern, the results such as the wavefront shape and corresponding first ten Zernike coefficients are calculated and are shown as outputs of the software. In addition, there is a special part in the program for atmospheric turbulence applications that calculates the strength amount of the turbulence, C_n² and the temporal evolution of the angle of arrival.

The goal is to study the possibility of creating intelligent automated systems for differential diagnosis of pulmonary diseases based on the identification of pathological structures in X-ray images of thoracic cavity organs using neural network technologies. A brief analysis of modern diagnostic techniques is presented, and a description of the proposed algorithm for determining the type of lung tissue pathologies used in the visual analysis of X-ray images and based on the identification of the main radiological syndromes, as well as on the evaluation of the quantitative characteristics of differential X-ray diagnostics, is given. By the example of classification of radiographs of healthy and tuberculosis patients, the effectiveness of using neural network technologies in the computer diagnosis of lung diseases is demonstrated. The studies are carried out using a publicly available database of X-ray images of thoracic cavity organs containing 3,500 images of healthy people and the same number of sick people images.

A method for producing biocomposite fertilizers with increased water resistance, based on the sequential impregnation of supports from pine bark with the solutions of urea and potassium dihydrophosphate is proposed. The structure of supports prepared from pine bark and fertilizers based on them was studied by means of scanning electron microscopy. The ability of biocomposite fertilizers based on pine bark supports to provide slow outwashing of mineral components with water for a long time was established. The treatment of fertilizers with water at room temperature for 15 days results in the removal of nitrogen, phosphorus and potassium by not more than 34.4, 74.3 and 58.4 wt. %, respectively (of the initial content), which evidences in favour of the prolonged action of biocomposite fertilizers based on pine bark. It is shown that the use of support obtained through extraction treatment of pine bark with organic solvents allows making a fertilizer with higher stability against nitrogen removal with water in comparison with the fertilizer based on the support prepared by treating pine bark with 1 % NaOH solution. Vegetation experiments on germination of Megion oat seeds revealed the same growth-promoting effect of biocomposite fertilizers based on supports obtained using different methods: the length of sprouts and roots increased by a factor of 1.5 in comparison with the reference experiment (water). The studies demonstrated the high potential of the developed fertilizers as an alternative to traditional water-soluble fertilizers and provided evidence of the possibility to obtain them using either original pine bark or wastes from its extraction processing.

The kinetics and mechanism of hydrogen evolution reaction on Mn₅Si₃ electrode in solutions x M H₂SO₄ + (0.5 - x ) M Na₂SO₄, where x = 0.5, 0.35, 0.20, 0.05, are studied by means of polarization and impedance measurements. It is established on the basis of direct- and alternating-current diagnostic criteria that hydrogen evolution reaction on manganese silicide (Mn₅Si₃) in sulphuric acid electrolyte proceeds via discharge - electrochemical desorption route. Both stages are irreversible, and the transfer coefficients of the stages are not equal. Adsorption of atomic hydrogen is described by the Langmuir isotherm. It is assumed that the hydrogen evolution reaction is complicated by the process of hydrogen absorption by the electrode material, proceeding with kinetic control (within the entire investigated potential range). The effect of a thin oxide film on the kinetics of hydrogen evolution on Mn₅Si₃ is noted at low cathodic polarizations. Keywords: manganese silicide Mn₅Si₃, hydrogen evolution reaction, sulphuric acid electrolyte, impedance

The production of many important carbon materials is currently based on the use of aromatic fractions of coal tar - a minor by-product in the production of metallurgical coke for the needs of ferrous metallurgy. Innovations to reduce the consumption of expensive metallurgical coke in blast furnace smelting and the priority development of the coke-free methods of steel production lead to a reduction in the output of coke-chemical products, which destabilizes the prospects for the production of important carbon materials, including those necessary for ferrous and non-ferrous metallurgy. The relevance of creating alternative methods for obtaining aromatic feedstock is substantiated. The potential of low-temperature coal processing by its thermosolvolysis with the production of concentrates of aromatic substances is shown. The possibility of their use as the raw material in the production of carbon anodes for the process of aluminum electrolysis is demonstrated.

To develop recommendations for the optimal consumption of food items considering the features of the Far North regions and the regional specificity of mineral composition, the content of 25 chemical elements was analyzed in the food items of local origin and those transported to the territory of the Magadan Region. It is determined that a portion of beef from cows grown in Magadan contains substantially higher amounts of calcium, sodium and phosphorus than beef samples brought from other regions. Locally produced beef liver contains higher concentrations of iron, iodine, manganese, and zinc. Locally produced pork contains significantly higher amounts of copper ( p = 0.01) and iron ( p = 0.1) in comparison with pork transported from other regions. Evaluation of microelement concentrations in vegetables in comparison with imported samples shows that local carrots contain higher selenium concentration, local cucumbers - higher potassium, copper, and manganese, beetroot is richer in selenium and zinc, with its portion being able to meet fully the daily demand for manganese. In all the analyzed vegetable samples imported from China, nickel content is higher than in local products. In addition, Chinese carrots contain reliably higher concentrations of boron and cobalt, tomatoes and cucumbers contain higher levels of chromium and vanadium, while silicon content is higher in vegetables from the Magadan Region. At the same time, neither of the examined samples exceeds the permissible levels of toxic elements.