Vol 526 (2026)

The article briefly presents the concept and the first results of the installation of a superconducting radio receiver of the sub-terahertz frequency range ~0,1 THz, in the focus of the 6-meter reflector of the BTA optical telescope of the SAO RAS. The conditions of the microwave astroclimate, which play a significant role in the limitations of sub-THz observations at the BTA, are described. The scheme of the optical alignment of the sub-THz receiver with the optics of the BTA is given, as well as the features of the technical solutions related to the deep cryogenic cooling of the sub-THz detector.

The saturated vapor pressure near the sublimation and boiling lines exhibits a nearly exponential dependence on the reciprocal temperature. This dependence is usually proposed as empirical or derived, under certain assumptions, from the Clausius-Clapeyron equation. This paper presents a microscopic analysis of the saturated vapor pressure within the framework of a model of vapor as an ideal monatomic gas. It is shown that within this model, the “nearly” exponential dependence of vapor pressure on the reciprocal temperature is preserved even with a temperature-dependent heat of vaporization. The weak temperature dependence of the pre-exponential factor is due to the significant compensation of the temperature contributions of the entropy of the gas and condensed matter. The pre-exponential factor in the equation for saturated vapor pressure is of quantum origin and is related to the kinetic energy density of gas particles, considered as quantum objects with a size on the order of the de Broglie wavelength.

The paper investigates the formation of luminescent centers in polycrystalline diamond films grown by microwave plasma chemical vapor deposition (MPCVD) on silicon substrates at substrate temperatures in the range of 850–1100 °C. In addition to the characteristic lines of diamond and the substrate, three emission centers were detected in the photoluminescence (PL) spectra: at 630, 720–722, and 738 nm, the latter of which corresponds to the Si–V defect. The nature of the centers at 630 nm and 720–722 nm has not yet been definitively established. It is shown that the center at 720–722 nm, like the Si–V defect (738 nm), exhibits dependence on synthesis conditions: its intensity reaches a maximum at a growth temperature of about 900 °C and increases significantly after additional thermal annealing. In contrast, the center at 630 nm is formed mainly during high-temperature deposition (1000–1100 °C). The results obtained make it possible to attribute the center with an emission maximum in the range of 720–722 nm to a new type of silicon color centers, as well as to determine the optimal conditions for its formation. Due to its spectral characteristics, it is of interest for photonics, in particular as a potential source of single photons.

A detailed analysis of the equation of motion of the Earth is given, describing its trajectory relative to the Sun, taking into account the Magnus effect, the origin of which is not prohibited provided that the total angular momentum of any mechanical system is preserved. This equation is obtained based on the solution of the variational problem on the conditional extremum. The numerical estimates of the predicting effect are given.