Efficiency of electron cooling in cold-electron bolometers with traps

Electron on-chip cooling from the base temperature of 300 mK is very important for highly sensitive detectors operating in space due to problems of dilution fridges at low gravity. Electron cooling is also important for ground-based telescopes equipped with 3He cryostats being able to function at any operating angle. This work is aimed at the investigation of electron cooling in the low -temperature range. New samples of cold-electron bolometers with traps and hybrid superconducting/ferromagnetic absorbers have shown a temperature reduction of the electrons in the refrigerator junctions from 300 to 82 mK, from 200 to 33 mK, and from 100 to 25 mK in the idle regime without optical power load. The electron temperature was determined by solving heat balance equa-tions with account of the leakage current, sixth power of temperature in the whole temperature range, and the Andreev current using numerical methods and an automatic fit algorithm

Numerical modeling of a multi-frequency receiving system based on an array of dipole antennas for LSPE-SWIPE

Here we present the results of a numerical modeling of mode composition in the constriction of the Large Scale Polarization Explorer-Short-Wavelength Instrument for the Polarization Explorer (LSPE-SWIPE) back-to-back horn. These results are used for calculating the frequency response of arrays of planar dipole antennas with cold-electron bolometers for 145, 210, and 240 GHz frequencies. For the main frequency channel (i.e., 145 GHz) we have a 45 GHz bandwidth. For the auxiliary frequency channels (i.e., 210 and 240 GHz) placed on the same substrate, we have bandwidths of 26 and 38 GHz, respectively. We performed some op-timizations for cold-electron bolometers to achieve a photon noise-equivalent power of 1.1 x 10-16 W/Hz1/2. This was achieved by replacing one of two superconductor-insulator-normal tunnel junctions with a superconductor-normal metal contact

Response of a cold-electron bolometer on thz radiation from a long yba2cu3o7−δ bicrystal josephson junction

The response of the Cold-Electron Bolometers (CEBs), integrated into a 2-D array of dipole antennas, has been measured by irradiation from YBa2Cu3O7−δ (YBCO) 50 \ub5m long Josephson junction into the THz region at frequencies from 0.1 to 0.8 THz. The possibility of controlling the amplitude-frequency characteristic is demonstrated by the external magnetic field in the traveling wave regime of a long Josephson junction. The YBCO junction has been formed on the bicrystal Zr1−xYxO2 (YSZ) substrate by magnetron sputtering and etching of the film. CEBs have been fabricated using an Al multilayer structure by a self-aligned shadow evaporation technique on Si substrate. Both receiver and oscillator have been located inside the same cryostat at 0.3 K and 2.7 K plates, respectively

Russian healthcare system digitalization: Opportunities and contradictions

The article is devoted to the opportunities and key contradictions of the Russian state healthcare system digitalization project implementation. The authors analyze various aspects of the system digitalization algorithms in light of the federal project “Creation of the Single Digital Circuit in Healthcare based on the Unified State Health Information System”. The aim of the article was to identify problems within goal-setting, documentation development, and practical implementation of the healthcare system digitalization project, as well as to come up with proposals for eliminating these issues. The analysis showed the inefficiency of the expensive healthcare system digitalization project, which has both objective and subjective reasons for its low effectiveness. The authors come to the conclusion that it is necessary to eliminate a number of contradictions and barriers in the framework of the project implementation in order to increase the efficiency of both the healthcare system itself and the high budget federal project of the economy digitalization as a whole. The practical significance of the article consists in the applicability of proposed approach to making the necessary amendments to the current federal project documentation, which will ensure a focus on real needs within the framework of the initiative implementation. The work may be of interest to civil servants, initiators of projects on the healthcare system digital transformation, governmental bodies, healthcare organizations managers, students, and practitioners

Record electron self-cooling in cold-electron bolometers with a hybrid superconductor-ferromagnetic nanoabsorber and traps

The Cosmic Microwave Background (CMB) radiation is the only observable that allows studying the earliest stage of the Universe. Radioastronomy instruments for CMB investigation require low working temperatures around 100 mK to get the necessary sensitivity. On-chip electron cooling of receivers is a pathway for future space missions due to problems of dilution fridges at low gravity. Here, we demonstrate experimentally that in a Cold-Electron Bolometer (CEB) a theoretical limit of electron cooling down to 65 mK from phonon temperature of 300 mK can be reached. It is possible due to effective withdrawing of hot electrons from the tunnel barrier by double stock, special traps and suppression of Andreev Joule heating in hybrid Al/Fe normal nanoabsorber

Protecting the rights of students in the learning process in higher education: the modern Russia

В статье рассматривается понятие «студенчество» и «защита прав». Проводится анализ защиты прав студентов в высшем учебном заведении в современной России.The article discusses the concept of "student" and "protection of the rights

Водный, тепловой и солевой баланс юго-восточной части Баренцева моря

The south-eastern part of the Barents Sea is located away from the main currents, with a combination of climatic, hydrological and oceanological processes creating conditions that make the region different from the rest of the Barents Sea such that it is seen as a separate region and called sometimes the Pechora Sea. Despite the intensive economic activity in the south-eastern part of the Barents Sea, it is not yet clear to what extent the general Atlantic water transport in the Barents Sea and, consequently, the transport of heat and salt, affects this region. Therefore, the aim of this study was to assess advective flows at open boundaries, as well as other components of the water, heat and salt balances of the south-eastern part of the Barents Sea. Based on monthly average data from the MERCATOR GLORYS12V1 reanalysis for the period 1993–2018, we calculated water transport, heat and salt flows at the boundaries of the south-eastern part of the Barents Sea (at 50° E in the west, at 71° N in the north and in the Kara Gate Strait); to close the balances, an assessment was made of sea-atmosphere interaction characteristics on the sea surface based on ECMWF ERA5 reanalysis data. Water, heat and salt balances were combined with a residual not exceeding 1.6 %. Linear trends for the characteristics obtained were calculated. It is revealed that the average long-term resulting water transport in the south-eastern part of the Barents Sea is directed from the north-west of the region to the Kara Gate Strait (0.40 Sv). This current is associated with the Atlantic waters and also carries heat and salt. The resulting heat input (5.92 TW) creates a heat excess in the water area, which is compensated for by interaction with the atmosphere (1.86 TW). The salt flow through the region is estimated at 13.98 t/s. During the study period, all the main flows have a statistically significant positive trend in the incoming and outgoing parts of the balances: water transport — 0.005 Sv per year; salt flow — 0.18 t/s per year. This indicates an increase in the transit of Atlantic waters through the south-eastern part of the Barents Sea. An increase in the advective heat flux (0.15 TW per year) across the western border is accompanied by an increase in its release into the atmosphere (0.07 TW per year) and an increase in evaporation of 6.9 mm per year. Sea levels are also rising at a rate of 0.27 cm per year. Thus, the increasing dynamics of the processes in the region is a factor to take into account in conducting economic activities.В статье представлены оценки адвективных потоков на открытых границах, а также других компонентов водного, теплового и солевого балансов юго-восточной части Баренцева моря (иногда называемой Печорским морем). По среднемесячным данным реанализов MERCATOR GLORYS12V1 и ECMWF ERA5 за период 1993–2018 гг. рассчитаны объемный расход воды, потоки тепла и соли на границах юго-восточной части Баренцева моря (западная граница по 50° в. д., северная граница по 71° с. ш. и разрез в проливе Карские Ворота); потоки тепла и влаги на поверхности моря. Балансы воды, тепла и соли собраны с невязкой, не превышающей 1,6 %. Выявлено, что адвекция через границы акватории играет главную роль в формировании всех балансов. Основной поток вод направлен с северо-запада акватории транзитом через пролив Карские Ворота в Карское море. На основании анализа линейных трендов показано, что все основные потоки имеют значимый положительный тренд. Это указывает на рост транзита атлантических вод через юго-восточную часть Баренцева моря. Также отмечен рост испарения и теплоотдачи с поверхности моря, связанный с ростом температуры воды

Spectral characteristics of the double-folded slot antennas with cold-electron bolometers for the 220/240 GHz channels of the LSPE instrument

We present the results of the experimental and theoretical study of the resonant properties and noise of a single cell of a receiving system based on cold-electron bolometers (CEB) with a double-folded slot antenna and coplanar lines. The system was designed to receive signals at 220/240 GHz frequencies with a 5% bandwidth. In measurements, we used the samples of the double-folded slot antennas with slot lengths of 162 um and coplanar line lengths from 185 to 360 um. Measurements of the resonance properties of CEB located at 0.3 K cryostat plate were carried out using a generator based on a high-temperature YBCO Josephson junction located inside the same cryostat at 4 K plate. This arrangement made it possible to obtain smooth amplitude-frequency characteristics with a clearly defined peak of a 15–21 GHz bandwidth at different frequencies. Based on these results, 2-D array of double-folded slot antennas with CEBs as 220/240 GHz LSPE channel prototype was calculated.The absorption efficiency of the array has reached 81% and 77% for 220 and 240 GHz channels, respectively

Исследование влияния процесса модификации на групповой состав битума и модификаторов методом Фурье-ИК-спектроскопии

Objectives. This study evaluates the effect of the modification process on the group composition of bitumen and bitumen binders containing rubber powder and hybrid modifier that is based on styrene–butadiene thermoplastic elastomer and rubber crumb. The aim of the study was to determine the presence or absence of functional groups that reflect the direction of physicochemical processes during the preparation of a hybrid modifier in rotary dispersers and during the modification of bitumen binders. Methods. Rubber powder and hybrid modifier were obtained by high-temperature shear grinding using a rotary disperser. Bitumen and modified bitumen binders were investigated via Fouriertransform infrared spectroscopy. Using the method of spectral subtraction, it was determined that during the process of manufacturing modified bitumen binders, structural changes occur in both bitumen and modifiers. During this study, the extraction of modifiers (rubber powder and hybrid modifier) in toluene was performed. Results. The quantitative analysis of changes in the group composition of modifiers before and after the modification procedure was carried out. The active polymer and structural indices were determined. The general trend of the change in the active polymer and structural indices was noted for the initial spectra of the rubber powder and hybrid modifier, and their spectra were obtained after the procedure of subtraction from the spectra of bitumen binders. Conclusions. The interdiffusion of aromatic compounds between the bitumen component and modifier particles was confirmed. On the basis of the results of the extraction of modifiers in toluene, and by taking into account the infrared spectroscopy data, it was determined that during the production of hybrid modifier during the simultaneous grinding of rubber crumb and styrene– butadiene thermoplastic elastomer, there was a chemical interaction between them. Цели. В статье проанализировано влияние процесса модификации на групповой состав битума и битумных вяжущих, содержащих резиновый порошок и гибридный модификатор на основе бутадиен-стирольного термоэластопласта и резиновой крошки. Целью исследования было определение наличия или отсутствия функциональных групп, отражающих направленность физико-химических процессов при получении гибридного модификатора в роторных диспергаторах и при модификации битумных вяжущих. Методы. Резиновый порошок и гибридный модификатор получены методом высокотемпературного сдвигового измельчения на роторном диспергаторе. Битумы и модифицированные битумные вяжущие исследованы методом инфракрасной спектроскопии с Фурье преобразованием. С помощью метода вычитания спектров установлено, что в процессе изготовления модифицированных битумных вяжущих происходят структурные изменения как в битуме, так и в модификаторах. В работе также проведена экстракция модификаторов (резинового порошка и гибридного модификатора) в толуоле. Результаты. Проведен количественный анализ изменений, происходящих в групповом составе модификаторов до и после процедуры модификации. Определены активный полимерный и структурный индексы. Отмечена общая тенденция в изменении активного полимерного и структурного индексов для исходных спектров резинового порошка и гибридного модификатора и их спектров, полученных после процедуры вычитания из спектров битумных вяжущих спектра битума.Выводы. Подтверждена взаимодиффузия ароматических соединений между битумной составляющей и частицами модификаторов. На основании результатов экстракции модификаторов в толуоле и с учетом данных ИК-спектроскопии найдено, что в процессе производства гибридного модификатора совместным соизмельчением резиновой крошки и бутадиен-стирольного термоэластопласта между ними происходит химическое взаимодействие.

Free-radical oxidation as a pathogenetic factor of metabolic syndrome

The medical and social significance of cardiovascular diseases remains high. One of the factors that determine cardiovascular risks is metabolic syndrome. As a result of excessive accumulation of lipid and carbohydrate metabolism products in metabolic syndrome, oxidative (oxidative) stress develops. The article considers both domestic and foreign scientific studies, which highlight various aspects of the influence of reactive oxygen and nitrogen species, as well as other free radicals on the formation of oxidative stress in pathological conditions that are part of the metabolic syndrome complex. This describes the mechanisms of the formation of chronic inflammation through excessive secretion of pro-inflammatory cytokines and adipokines, activation of the transcription factor NF-kB, as well as damage to the antioxidant system in obesity. Separately, a number of mechanisms of the stimulating effect of adipokines: leptin, adiponectin, chimerine, omentin 1, resistin, on the formation of oxidative stress have been noted. The ways of activating the polyol pathway, as well as diacyl-glycerol — protein kinase C — the signaling pathway of oxidative stress, the formation of mitochondrial dysfunction is described. As a result of which there is an excessive production of free radicals in insulin resistance, diabetes mellitus and macroand microvascular complications of diabetes. In addition, the influence of oxidative stress directly on the formation of cardiovascular diseases of atherosclerotic genesis, as well as arterial hypertension, has been shown