This article investigates the capabilities of the modified method of auxiliary sources (MAS) for solving the direct problem of subsurface radar sounding of layered inhomogeneous media of Arctic soils, including cylindrical doubly-connected dielectrically inhomogeneous regions. In this modification of MAS, the fields of auxiliary sources (AS) are represented as a superposition of zero-order Bessel functions, zero-order Hankel functions of the first kind, and their derivatives with respect to the normal direction to the level line, which made it possible to solve the boundary value problem with open interfaces of a plane-layered inhomogeneous medium. The time-domain waveforms calculated by MAS were verified using the finite-difference method (coefficient of determination 0.998, root-mean-square deviation less than 6 V/m). It is shown that the modified MAS provides a reliable solution to the direct problem of subsurface radar sounding over a wide range of soil properties, including seasonally frozen soils, and can be used in algorithms for processing ground-penetrating radar data for monitoring pipelines and road structures in permafrost regions.
Some special feature of chaotic magnetization precession in anisotropy medium type of [001] by large precession angles are investigated. It is found the motion equation which are solved by Rounge-Cutta method. It is found the magnetization vibrations in time development and corresponding precession portrait. For interpretation of received results the model of dynamic potential is proposed. From criterion of magnetization and external field it is found three levels of cubic anisotropy degree: weak, middle and strong. For all three anisotropy levels the potential surfaces in transverse magnetization components in plate flatness are constructed. It is shown that the most opportunity case for chaos achieving is the middle anisotropy case. The conditions of chaos achieving are investigated. It is proposed the algorithm which allow the excitation level and frequency of alternative field determined to chaos achieving. It is proposed some recommendations for further investigations.
In this paper, the optical method of instantaneous microwave frequency measurement based on optoelectronic mixing with frequency-modulated optical signal is proposed. The analytical model of the microwave photonic device realizing this method is developed. The principle of measuring microwave signals frequency based on the proposed method is described, and the possibility of simultaneous measurement of multiple microwave signals frequency in the range up to 4.5 GHz with a measurement uncertainty of less than 30 MHz is experimentally demonstrated.
In recent years, Russia has been actively searching for and studying the astroclimate of potential sites for a large millimeter/submillimeter (MM/subMM) telescope, including as part of the Eurasian Submillimeter Telescopes (ESMT) project. To this end, suitable sites were identified and new astropoints were established in northern Eurasia between 2021 and 2023: Khulugaysha Peak (Eastern Sayan Mountains), Kurapdag Mountain in the Agulsky District of Dagestan, and the Tashanta APT in the Altai Republic. The astronomical site of the Large Alt-Azimuthal Telescope (BTA, Pastukhova Mountain) was selected as reference location for comparing atmospheric characteristics. The new astropoints are characterized by low values of precipitable water vapor and total cloud cover. Meteorological measurements indicate a high frequency of weak surface wind gusts in the villages of Tashanta and Khulugaysh, as well as regular gusts exceeding 30 m/s near Mount Kurapdag. As alternatives to Mount Kurapdag, we consider Mount Jufudag in the Agulsky District and the high-mountain Shunudag Plateau in the Kulinsky District of Dagestan. This paper compares the astroclimatic conditions of Mount Jufudag and the Shunudag Plateau with those of Mount Kurapdag, Mount Pastukhova and other astropoints. Maps of precipitated water vapor, total cloud cover, and wind gust speed for the North Caucasus were obtained using Era-5 reanalysis data, and their median estimates are provided, taking into account the terrain. The mesoscale WRF model was used to achieve greater map detail. The paper presents the first results of measurements of optical thickness and precipitated water vapor in the area of Mount Jufudag and the Shunudag plateau, obtained using a two-channel radiometric atmospheric transparency meter IPAR-2 in March-April 2025. The first results of measurements of meteorological parameters and astronomy seeing in the area of Mount Jufudag using an ultrasonic weather station and Polar-2 optical monitor are presented.
A technology for manipulating whisker-like single crystals (whiskers) of quasi-one-dimensional charge-density-wave (Q1D CDW) semiconductors was developed for the fabrication of suspended structures. A current-controlled microgripper based on shape memory alloy (SMA) composite ribbons was created. A technique for capturing and fixing whiskers using a micromanipulator and a tungsten probe was developed, together with a method for contact formation employing a mask transferred by the microgripper followed by metal deposition. Resonant modes of high-frequency electromechanical oscillations in a suspended TaS₃ whisker were detected and investigated using the heterodyne method.
