Solitons in a nonlinear transmission line are studied theoretically, experimentally, and through simulation in NI Multisim 11.0 software. A line consisting of a long sequence of LC cells with BB112 varactors as nonlinear elements is studied in detail. Longitudinal currents arising in the line during the propagation of solitons are investigated thoroughly (previous works analyzed only the voltage between the conductors of the line). Based on the KdV equation, a formula is derived to describe the current soliton profile, which for small amplitudes takes the standard form similar to sech2(x). The unipolar current profile in the line indicates unidirectional charge (and, consequently, matter) transport by solitons. The electric charge transported by solitons is calculated and measured experimentally. The dependence of the charge transported by the soliton on its amplitude is obtained. It is shown that the charge transported by the soliton is uniquely related to its amplitude. Moreover, it is demonstrated that charge transport cannot be neglected for solitons of any amplitude, including arbitrarily small ones. Thus, a new parameter of the solitons, namely their electric charge is established. In experiments, an original excitation method is employed, involving the discharge of a pre-charged capacitor into the line. This process leads to the generation of one or several solitons followed by a periodic "tail". It is shown that the initial charge of the capacitor is approximately equal to the total charge carried by the excited solitons (in the absence of dissipation). The theoretical, simulation, and experimental results are in good agreement.
High-strength steels are increasingly used to manufacture welded structures in various industries, significantly im-proving the performance characteristics of products. These strength properties can be achieved through specialized alloying systems, thermomechanical processing, and other methods. The higher the strength and the more complex the strengthening system, the less its technological weldability. Currently, high-strength thermomechanically strengthened steel is increasingly used for the manufacture of welded structures. It offers the required armor resistance at relatively thin sheet thicknesses, but at the same time, it is highly susceptible to cracking in the near-weld zone. Cracks form immediately after welding, as well as over time during operation and external loads. The main cause of their formation is high level of internal stress and hardness values near the fusion line in the base metal, caused by the influence of the thermal cycle of welding. This article, based on the results of experimental studies and mechanical tests of welded joints made of high-strength armor-resistant steel 37Y, propo-ses a heat treatment option to reduce the hardness in the heat-affected zone near the fusion line, which significantly reduces the likelihood of crack formation. The essence of the proposed solution consists of heating the heat-affected zone of a welded joint made by consumable electrode arc welding (MIG) in a protective gas environment of 98 % Ar + 2 % O-2 using an auste-nitic welding wire 03-08X20H101-7T, through the deposited weld metal using non-consumable tungsten electrode (TIG) welding technology. Local heating of the weld beads is carried out until a liquid pool mirror appears, and all welded joints are processed by rectilinear movement along the axis of the weld. The features of hardness distribution in the heat-affected zone of welded joints made of high-strength steels and the nature of the effect of local heating on them are studied.
Demographic policy is one of the priority tasks of the Russian Federation at present. Positive demographic dynamics are necessary for the progressive socio-economic development of modern Russia. The importance of solving the demographic problem cannot be overestimated: "For a successful future for Russia, for its development," emphasized Russian President V. Putin at a meeting of the State Council on December 20, 2024, "there must be many more of us, Russians". The main sign of a negative demographic situation in Russia is the growing scale of depopulation (population extinction). If the natural population decline in 2019, according to Rosstat, amounted to 317.2 thousand people, then in 2020 it reached 688.7 thousand people, in 2022 - to 599.6 thousand people. Low standard of living and quality of life in the regions, the COVID-19 pandemic, poor healthcare system and other factors related to the social sphere have become catalysts for the growth of depopulation, which in 2021 reached a record level of more than 1,000,000 people. Depopulation has affected almost all regions of Russia. Thus, the population of the Amur, Kirov and Pskov regions has decreased by 24% over 11 years, Arkhangelsk - by 26%, Sakhalin - by 31%, Murmansk-by 34%. If this negative trend continues, then, according to the forecast of Rosstat, by January 1, 2046, the population of the Russian Federation will decrease to 138.77 million people. President V. Putin explained the failures in demographic policy by the consequences of past years, mainly the period of President B. Yeltsin's rule. According to him, in the so-called "dashing 90s" due to shortcomings in social policy there was a sharp decline in the birth rate, which subsequently led to a demographic hole. The growing scale of depopulation is becoming an obstacle to achieving the goals voiced by President V. Putin in his famous decrees and addresses to the Federal Assembly. To solve demographic problems, at the initiative of the head of state, two demographic concepts were developed and approved at the beginning of the 21st century: the first for the period from 2001 to 2015 and the second until 2025. On February 11, 2019, the government published the passport of the national project "Demography", for the implementation of which the government allocated more than 3 trillion rubles. Since 2025, new national projects "Family", "Youth and Children", "Long and Active Life" are aimed at solving demographic problems.
The Common Kestrel (Falco tinnunculus) has shown a significant population decline in Latvia. During survey for the European Breeding Bird Atlas 2, breeding of this species was confirmed only in 17 of 5 × 5 km squares. The first nest boxes for this species were installed in the Grobina region in 2014. Most of the chicks were ringed using colour rings, and trail cameras were increasingly used to monitor presence of ringed birds and the reasons of nests being destroyed. In 2025, of the 105 Kestrel nest boxes installed, 33 were occupied by Kestrel, 23 of which were successful, 5.40 nestlings for successful nests were recorded and 4.22 nestlings for occupied nests. In 2025, 128 chicks were colour-ringed, and 32 trail cameras were installed. It was observed in trail cameras that at least eight nests in 2022 to 2025 were destroyed by Pine Marten (Martes martes). Therefore, starting from 2024, nest boxes were installed on wooden electricity poles in the middle of field – in places less likely to be visited by Pine Marten. In 2025, 15 nest boxes out of 39 installed on electricity poles were used by Kestrel. One nest in a nest box installed on an electricity pole was destroyed far by Pine Marten in 2024, and none in 2025.
