Electromagnetic radiation of the terahertz range (THz) is used in various fields of science and technology: medical diagnostics, security and control, sensor and communication technologies, scientific research, etc. Computer simulation in the development and research of THz receivers significantly reduces costs and time-to-market by replacing expensive experiments. Advanced software suites, like HFSS, facilitate the accurate modeling of intricate three-dimensional configurations and the analysis of component electrodynamic performance. This study leveraged HFSS to simulate the performance of a THz receiver across the 0.4–1.4 THz band. The accuracy of the simulations relies on the fidelity of the model, encompassing geometric details, material properties, and chosen simulation parameters. This paper proposes a three-dimensional model of an original selective compact receiver of terahertz electromagnetic radiation (with a conversion efficiency of~97 %) for two resonance frequencies, consisting of a sensor based on two open apodized periodic microcavity structures with a fill factor changing according to a linear law, a matching element in the form of an asymmetric irregular triangular strip line, and a detecting diode. The design offers key advantages including high conversion efficiency, suitability for matrix architectures, high selectivity to registered radiation, and the potential for simple readout methods, making it an attractive approach for THz sensing, an important tool across various scientific and practical applications.

Bipolar transistors are the main element base in electronics. The development of this base was carried out mainly through experimentation. To justify the operation of the transistor, qualitative representations were used in the form of a double р–n junction of the р–n–p or n–p–n conductivity type. With this justification, many properties of a working semiconductor transistor remained beyond their clear understanding. Therefore, in this paper, the design of a bipolar transistor is considered, taking into account the structure of the solid body of the semiconductor base and the interaction of atoms in the form of negative ions with the surface of the solid body. Based on the analysis of data obtained by a tunneling microscope, the surface of the solid is covered with a monomolecular film, and the crystal of the semiconductor base itself is formed by positively charged atoms and is located under the monomolecular film. The molecular film is formed by surface clusters, and the crystal is formed by volume clusters. The interaction of surface clusters creates a porous structure of the molecular film. Through these pores the crystal of the solid body is visible. Impurities in the form of individual molecules penetrate the surface of the crystal through holes in the molecular film, formed in the form of columnar voids. On the surface of the crystal, impurity molecules, as a result of exchange interaction, dissociate into individual atoms, which in turn, also as a result of exchange interaction, are converted into negative ions. The doping of the surface of a semiconductor crystal of germanium or silicon with arsenic and indium molecules is specifically considered. After the molecules disintegrate into atoms in the columnar voids, they are converted into negative ions, which block the penetration of other molecules into these voids.

Nowadays micro-grids are employed to improve the resilience and stability of power systems. The supervised operation of several distributed generation (DG) in a distribution system will give customers enough options to select the better solution under various priorities. Strategic planning studies with a variety of options are presented to the decision-maker. Major problems faced by decision-makers are assigning weights to the attributes, using attribute data for various alternatives, and making final decisions. These problems can be effectively managed in the multi-attribute decision-making approach. It deals with choosing the best option from a large but finite number of options while taking into account how each option performs concerning several attributes. In this paper optimal planning of a DG using the R method considering various configurations such as hybrid DG, Micro-grid, and the grid is presented. Three attributes such as reliability, incremental cost, and T&D losses are considered in this paper. The results are compared with the Analytical Hierarchy Process approach. The R method is a relatively simple and efficient as it requires less time, limited attention of the decision maker, and a high capacity for processing the information. This research paper will help to develop a control algorithm using fuzzy for strategic planning of DGs.

The study considers one of the areas of modern surface nano-engineering using technologies for controlled formation of topological coatings of a given configuration under laser action on various samples, taking into account approaches for complex nonlinear thermodynamic systems with the development of dynamic non-equilibrium processes. The proposed technologies are universal in nature and are very promising, in particular, for metallic materials in the working chambers of thermal power plants. At the same time, the emphasis is placed on new physical principles for changing the functional characteristics of the sample material with their optimization for specific operating conditions of the sample with the formation of 1D 3D microand nanostructures, including dendritic type with fractal objects. Methods of controlled laser synthesis of surface topological structures were used in different experimental schemes with laser ablation. These controlled processes are implemented on the surface of products without changing the volumetric characteristics of the material, unlike the technologies of its standard heat treatment, for example, to increase wear resistance. Specifically, the first part of the presented article deals with the fundamental problem of laser thermodynamics of the emergence of dendritic/fractal structures on the surface of a material under conditions of the development of non-stationary thermophysical processes. The emphasis is placed on stable surface states of the material during its specialized preliminary laser processing, including the synthesis of various inhomogeneous and multilayer configurations on the surface with a certain 3D topology. The possibilities of achieving the required characteristics of the material used in a controlled manner to improve the performance properties of various systems are discussed. In particular, this also applies to dynamic gas-liquid thermal power plants with controlled laser guidance of adjustable local configurations of topological microand nanostructures on the inner metal surface of their working chambers. As an experimental demonstration, the micro-cracked surface structure of metal-carbon materials was considered within the model of their graphitization

The article discusses the main stages of the study of the developed degassing technology that ensures energy efficiency and environmental friendliness of the production process. The presented analysis substantiates the relevance of the study within the framework of the current legislation and industrial safety requirements for the organization of gas-hazardous works and the technical reliability of gas holders. It was noted that reducing the cost of degassing is one of the priority tasks of a scientific and applied nature, due to the fact that this process consumes significant energy resources, uses specially prepared water for steam and complex technological equipment that requires the involvement of highly qualified and specially trained specialists. The main technical characteristics and functional purpose of the unit elements are given, and the advantages of the developed degassing and ventilation device ДВУ-ФС[DVU-FS]-1/450 are described. On the basis of the study, the most effective empirical values of maximum permissible concentrations and the conditions for their achievement were determined, taking into account the calculations of the material balance. The main stages of gas tank degassing are substantiated and the dependencies of the duration of each of the three stages are mathematically determined using mathematical calculations. Based on the results of the experiment, the key stages of the study were evaluated, an analysis of the obtained control indicators was carried out, on the basis of which mathematical calculations and modeling of the process of the developed gas tank degassing technology were carried out. The dependence of the change in the oxygen concentration in the gas space of the gas holder on the time of degassing was revealed and the expediency of taking it into account when determining the criteria for the qualitative assessment of the process was determined. The obtained diagram of the change in oxygen concentration during degassing of a gas holder is presented, depending on the rate of its decrease at different stages, which together make it possible to determine the optimal degassing time and perform economic calculations to assess the efficiency of the process. Based on the presented main scientific and technical results, substantiated criteria for assessing the environmental friendliness of production activities and low energy consumption have been determined in comparison with steaming in the conditions of preparation of technological equipment for liquefied petroleum gases operating in a propane environment.

The article considers the solar energy resources of the Kara-Bogaz-Gol Bay as a “solar pond”. Using the developed physical and mathematical methods, the thermal energy potentials оf the accumulation of salt deposits in the bay were determined for the creation and use of energy technologies in industrial sectors. Thermal energy characteristics for the introduction of various solar energy storage technologies were assessed; according to preliminary calculations, the effi ciency of a solar reservoir is 1.14 % in winter and 1.46 % in summer. The solar energy potential of conversion into thermal energy varies from 40 to 70 % depending on the season of the year. The average temperature on the salt surface of the reservoir bottom in summer ranges from 55.04 to 79.8 °C, in winter from 20.0 to 25.6 °C. The obtained scientific results can be used in the deve- lopment of design and estimate documentation, preparation of  feasibility studies for the creation of various solar energy technological complexes in the Caspian region, which will contribute to strengthening energy security, development of energy systems and production of autonomous technological installations and equipment based on solar energy, which will reduce the energy consumption of fossil fuels and improve the environmental situation in the Kara-Bogaz-Gol region.