We developed the model of the internal phonon bottleneck to describe the energy exchange between the acoustically soft ultrathin metal film and acoustically rigid substrate. Discriminating phonons in ...the film into two groups, escaping and nonescaping, we show that electrons and nonescaping phonons may form a unified subsystem, which is cooled down only due to interactions with escaping phonons, either due to direct phonon conversion or indirect sequential interaction with an electronic system. Using an amplitude-modulated absorption of the sub-THz radiation technique, we studied electron-phonon relaxation in ultrathin disordered films of tungsten silicide. We found an experimental proof of the internal phonon bottleneck. The experiment and simulation based on the proposed model agree well, resulting in τe−ph∼140–190 ps at TC=3.4K, supporting the results of earlier measurements by independent techniques.
An analytical method for preliminary assessment of the compactability of charges made from fine materials of the mining and smelting industry is developed. The method allows establishing the ...functional dependence of the density of a briquette on the applied pressure without experiments on the compression of a charge in special pressure equipment. The method involves the use of a new compaction model and the relationship between the compact density at a given pressure and the physical and mechanical properties of a charge (loose bulk density, tapped bulk density, true density of particles) for dry charges and charges mixed with water or liquid binder. The method can be used in briquette production when choosing processing modes and creating pressure equipment.
The binomial distribution is often used in modeling, including in applied climatology, when assessing the likelihood of adverse or dangerous climate-related impacts. The article outlines an algebraic ...algorithm for obtaining such estimates based on climate monitoring data or modeling data. Using only algebraic operations in calculations minimizes calculation time, which is important when performing detailed global assessments. As an example of such a calculation, the result of an assessment of the global climatic range of a dangerous insect pest of forest and garden trees and shrubs, the gypsy moth, is given.
The Multi-Purpose Detector (MPD) is constructing to study the properties of the hot and dense matter created in heavy-ion collisions in the energy range of 4-11 A*GeV where the maximum baryonic ...density is expected. The crucial detector in the new experimental setup is a large-sized barrel electromagnetic calorimeter (ECal), designed for precise spatial and energy measurements for photons and electrons. Taking into account the requirements of high energy resolution, dense active medium with the small Moliere radius, and high segmentation of ECal, the Shashlyk-type electromagnetic calorimeter with projective geometry has been selected. The mass production of ECal modules has been started. In this talk, we report about methods and technologies for the quality control of ECal modules and their components.
Experiments for verification of a functional dependence of the ablation pressure on the irradiated surface of a target upon the laser intensity in a range from 1.2 to 350 TW cm2 have been carried ...out. For that, at some intensities of the laser irradiation, time intervals between the laser pulse maximum and the moment of the shock-wave front arrival to the rear surface of the target were measured, which are dependent on the ablation pressure. Two schemes of the measurements were used. At the first scheme, at higher laser intensities, the front arrival moment is determined via an electron-optical camera when the rear surface begins glowing. At the second scheme, the front arrival moment is recorded when a probe laser pulse changes the character of the reflection by the rear surface of the irradiated target. Results of measurements are in agreement with the ablation pressure dependence upon the laser pulse intensity within 20%.
The influence of the 27-day solar oscillation on the temperature and intensity of the airglow of the mesopause region based on the hourly midnight observations of the О
2
А(0-1) and ОН(6-2) bands at ...the Zvenigorod Scientific Station in 2000−2021 has been studied. It is found that the response to solar activity changes is observed in all characteristics of the atmospheric emissions both by the yearly and seasonal data. They are statistically significant for all characteristics of the atmospheric emissions in winter and only for the О
2
А(0-1) intensity in summer. The positive response of the molecular oxygen emission is lower in the summer than in the winter by approximately a factor of 2. It is found that the variations in the atmospheric emission characteristics are close to antiphase with a 27-day solar oscillation. At the same time, the temperature of the emitting hydroxyl in winter undergoes oscillations with a shift by a third of the period relative to the solar variation maximum.
Using climate monitoring data from 96 Russian weather stations, the years of severe droughts are identified. For this purpose, the following criterion was used: a value of the Selyaninov hydrothermal ...coefficient for May–August is less than 0.6. Climate of a time period, i.e., a set of consecutive years, is considered unfavorable for the cultivation of grain crops if the frequency of severe droughts
p
(the Bernoulli distribution parameter) exceeds 0.5. This parameter is estimated from data of the considered weather stations separately for the time periods of 1976–1997 and 1998–2019 based on the number of the identified severe droughts. The probability that
p
> 0.5 is estimated, and the corresponding schematic maps are constructed for both time periods. The highest probability is obtained for the stations located in the Astrakhan, Volgograd, Saratov, and Orenburg oblasts, the Republic of Kalmykia, and the Republic of Crimea. At the same time, a noticeable increase in this probability in the second period relative to the first one is found for the Volgograd and Saratov oblasts.
In this work, we investigated the redox transients of a number of water-soluble spin labels upon their interactions with Photosystem II (PS II) core complexes isolated from spinach leaves. We have ...found that the reactivity of nitroxide radicals, determined by the rate of their reduction upon illumination of PS II, depends on the chemical structure of radicals and the capability of their coming close to low-potential redox centers of photoactive PS II complexes. An enhanced capability of nitroxide radicals to accept electrons from PS II correlates with their chemical structure. Nitroxide radicals NTI (2,2,5,5-tetramethyl-4-nitromethylene-3-imidazolidine-
N
-oxyl) and Tacet (4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl-acetate), containing polar groups, appear to be most efficient acceptors of electrons donated by PS II compared to neutral (TEMPOL, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl) or positively charged (Tamine, 4-amino-2,2,6,6-tetramethylpiperidine-l-oxyl) spin labels. We assume that enhanced reactivities of polar nitroxide radicals, NTI and Tacet, are determined (1) by their relatively high redox potentials, providing the possibility to accept electrons from PS II, and (2) by their affinities to the closest binding sites on the surface of PS II in the vicinity of the primary plastoquinone acceptor PQ
A
(12–14 Å) or/and in the intraprotein cavity for the secondary plastoquinone PQ
B
(~ 22 Å).
Optimization criteria are proposed for processes of separating ethylene and propylene from a mixture of low-boiling gases. These criteria are based on the physicochemical properties of substances and ...take into account special techniques used for separating such mixtures. Unlike the existing criteria based on considering the heat input to the reboiler and the heat output from the condenser of a distillation column, these optimality criteria more accurately evaluate the economic performance of the process, because they include the refrigerant preparation cost, which plays a decisive role in separating low-boiling gases. Four known methods of separating mixtures of low-boiling gases are considered: (A) separation in a column with steam as the heat-transfer medium in the column reboiler and with a refrigerant in the condenser, (B) separation in a column with the condensation of the vapor of a refrigerant in the column reboiler and with the same refrigerant in the condenser, (C) separation in a column with the condensation of the vapor of the
i
th refrigerant in the column reboiler and with the
j
th refrigerant in the condenser, and (D) separation in a column with steam as a heat-transfer medium in the column reboiler and with recirculating water in the condenser. Parameters that are expediently used as optimality criteria are identified. New approaches to creating the optimal processes of separating low-boiling gases are developed and theoretically justified for further implementation.
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