The floating ice cover determines the dynamic interaction between the ocean and the atmosphere, affects the dynamics of not only the sea surface, but also subsurface waters, and both the ice cover and the entire mass of liquid beneath it participate in the general vertical movement. This work investigates the amplitude-phase structure of wave fields arising at the interface between ice and an infinitely deep homogeneous fluid during flow around a localized source of disturbances. The ice cover is modeled by a thin elastic plate, the deformations of which are small and the plate is physically linear. An integral representation of the solution is obtained and, using the stationary phase method, an asymptotic representation is constructed for small disturbances of the ice cover far from a localized source. The results of calculations of dispersion dependences for various parameters of wave generation are presented. It is shown that the main parameters that determine the characteristics of the amplitude-phase structure of wave disturbances on the surface of the ice cover are ice thickness and flow velocity. Numerical calculations demonstrate that with changes in flow velocities and ice thickness, a noticeable qualitative restructuring of the phase patterns of excited far wave fields at the interface between ice and liquid occurs.

The paper presents an installation for studying a number of parameters of assemblies based on silicon photomultipliers and scintillation crystals, such as noise characteristics, gain and temperature stability of SiPM. The installation also allows you to shoot single-electron spectra, study energy and time resolution, light output, as well as temperature stability of various scintillators. A block diagram of the installation is given and the principle of its operation is described. The necessary macros for mathematical packages have been developed, as well as software for collecting, processing and storing data from a temperature sensor in the form of an MFC application on Windows OS. The results of testing the operating parameters of the installation, confirming its functionality, are presented, comments and shortcomings requiring corrections and improvements are identified. With the help of the installation, studies were carried out on the study of temperature dependences, the dependences of energy resolutions on the scintillation crystal and on the silicon photomultiplier, and a single-electron spectrum was obtained for further study and measurement of the relative light output for various scintillators based on the reference.

Linear one-dimensional equations of reaction-diffusion type with a constant delay are considered. Exact solutions of such equations are described, which are expressed in elementary functions. Closed-form solutions are obtained for the corresponding initial-boundary value problems with common initial data and boundary conditions of the first, second, and third kind, as well as mixed boundary conditions

The article considers a variant of circumstances under which a nuclear power plant operating in a variable daily load schedule receives a signal about the likely onset of extreme external influences in the near future, which will force the shutdown of the reactors. At the same time, the plant personnel is authorized to establish the mode in which the reactors will operate during the threat period until it is realized or canceled. A two-level daily graph of the change in the power of a nuclear reactor is given. It is believed that a threat warning is received at the beginning of the period, then, for the period of the threat of extreme external influences, the reactor power is set constant at a level between day and night regimes. The problem of finding the optimal power level was posed and solved, while the loss function is calculated as the total economic damage weighted by the probabilities of the implementation and cancellation of the threat: due to deviation from the consumption schedule in the event of a false alarm; due to downtime in the iodine pit in the event of a real threat. The results of the work allow us to draw the following conclusion: with an increase in the probability of a threat, the optimization effect increases, therefore, the power mode should be changed to the appropriate level 𝛼. Estimates of the optimization effect are given.

In the case of parallel use of several human-machine interfaces, there is a problem of command selection, when recognizing conflicting commands coming from different interfaces. To solve this problem, the decomposition algorithm can be used. In the case of decomposition, the most efficient combination of command-interfaces is selected for the operator, and the remaining combinations are ignored. There is an improvement to the decomposition algorithm: the command interpretation algorithm in which these ignored combinations are used to improve the efficiency of the interfaces. In this article, the decomposition and interpretation of commands algorithms for multi-channel human-machine interface are considered, and flowcharts of these algorithms are designed and analyzed. Based on this analysis, the modification of the command interpretation algorithm for a multi-channel human-machine interface was proposed. This modification allows to reduce the number of calculations to investigate the possibility of interpreting an ignored command. To compare the existing command interpretation algorithm and its developed modification, a number of experiments were carried out based on the generated confusion matrices. The expediency of using a modified algorithm for highly efficient interfaces was shown

A system for doubling the repetition rate of laser optical pulses in the mode-locked mode, which is designed to form a selection sequence in analog-to-digital photonic connections, is considered and experimentally tested. The basic idea of pulse repetition rate multiplication is to isolate the original pulse sequence and then the corresponding time delay to separate the pulse signals and their effects. The division and addition can be carried out both by branching and by gratings or by demultiplexers. Shown analytical description depends on the time delay in the signal arms and the spectrum obtained in the process of photodetection of the generated sequence. The amount of delay between pulses is adjusted in such a way as to minimize unwanted spectral components at multiple repetition rates of laser frequencies in the microwave spectra of the photodetected sequence, in which odd-order terms are minimized. It is shown that the effect of changing pulses also affects the caution of the proposed method.To considering the data in experiments with the results of the computational calculation, it was possible to achieve an accuracy of mismatch in time between pulses of no more than 100 femtoseconds, and a power difference of no more than 1 %. The jitterwascalculated using phase noise measurements is 10.2 femtoseconds.

The explicit exact formula for the volt-ampere characteristic (VAC) of a dc-circuit in the form of a cube, in the edges of which the same nonlinear Mott-Gurney elements are installed, is derived. The formula derivation is based on the decomposition method of complicated electric circuits and on the application of auxiliary formulas for VAC of serial and parallel connection of such elements, which were also obtained in this work. The formula can be used for calculating the VAC of large networks containing cubic cells with light-emitting diodes and solar cells.

Ordinary differential equations and partial differential equations with constant and variable delay are considered. Exact, approximate analytical and numerical methods for solving such equations are presented. The most common mathematical models with delay used in population theory, biology, medicine and other applications are described.