Superconducting Single-photon Detectors Made of Ultra-thin VN Films

We optimized technology of thin VN films deposition in order to study VN-based superconducting single-photon detectors. Investigation of the main VN film parameters showed that this material has lower resistivity compared to commonly used NbN. Fabricated from obtained films devices showed 100% intrinsic detection efficiency at 900 nm, at the temperature of 1.7 K starting with the bias current of 0.7·

Intermediate result of negative consequences of the epidemic of the new coronavirus infection for the global economy

The epidemic of the new SARS-CoV-2 coronavirus infection slowed global economic growth and became the main threat for the global economy and financial markets in 2020. Authorities in many countries around the world have declared a health emergency. Without the experience of state quarantine, countries have faced negative consequences for citizens, the economy and financial market participants. The introduction of temporary regulatory easing in the context of the spread of a new coronavirus infection assisted to partially limit the negative consequences. The next few months will, probably, have a particularly strong impact on small business, as government support schemes are reduced or ceased. The article reveals the main consequences of the new coronavirus infection for the global economy

Spin pumping in YIG-Pt structures: the role of the van Hove singularities

Spin pumping by surface and backward volume magnetostatic waves in YIG/Pt structures is experimentally studied and analyzed. It is shown that at frequencies corresponding to van Hove singularities in the density of states of the spin wave spectrum, an increase in the efficiency of electron-magnon scattering and spin current generation takes place. The obtained results are important for spin wave-based spintronic devices development

Communicative competence of a cardiologist: ethical and psychological analysis

The article problematizes the issue behind the standard categories of psychosocial factors, informing a patient about disease, prognosis, treatment methods, etc. The issue of a doctor’s role in interaction with a patient. Although psychological research methods are actively used in cardiology practice, and their results are quite transparent and demonstrate the specifics of patients experiencing the disease, affective states, soping skills, there are still questions about a physician not as a biomedical expert, but as a helping specialist. And although deontological imperatives require quite clear personal qualities from a doctor, the very realization of these qualities should be based on psychological approaches and culturalpsychological categories. As such, the way a doctor interacts with a patient can be described in terms of virtue ethics, which is an integral category that describes personal characteristics. Such characteristics, being implemented directly in clinical communication, could become a universal “recipe” for meaningful cooperation

Результаты оценки трибологических свойств авиационных масел для двигателей воздушных судов

The development of modern heat-stressed aircraft engines is a complex process based on the advanced achievements of various branches of science and technology, including chemmotology. Each new generation of aircraft engines imposes stricter requirements on the quality of the aviation oils used to ensure the reliable operation, including engine oil systems, rotor bearings and other components. One of the important factors in reducing friction and wear-out of modern gas turbine engines is the use of high-quality oils with a high level of anti-wear and anti-friction properties which allow engines to operate under various relubrication intervals. In the domestic regulatory and technical documentation, the anti-wear properties of aviation oils are evaluated using a four-ball friction machine according to GOST 9490, and the anti-friction properties are not taken into account. The specified friction machine has a variety of disadvantages. In this regard, the authors evaluated the anti-wear and anti-friction properties of domestic aviation oils using a versatile vibro-tribometer which allows for the operational properties of oils to be researched under the modes that are the most characteristic for the actual operation of aircraft engines compared with parameters of oil tests by a four-ball friction machine. Unlike the four-ball friction machine, the vibro-tribometer design implements a contact - interaction scheme in a “ball-plate plane” friction pair. At the same time, a thermal chamber is installed on this application that provides constant heating of the friction pair and the tested lubricating oils to the required temperature (from 0 to 150 ℃). It has been found that IPM-10 aviation oil possesses the best anti-wear and anti-friction properties, and with an increase in the tested oil temperature, a proportional increase in wear-out in the “ball-plate plane” friction pair occurs.Разработка современных и теплонапряженных авиационных двигателей является комплексным процессом, который основывается на передовых достижениях различных отраслей науки и техники, включая химмотологию. Каждое новое поколение авиационных двигателей предъявляет более жесткие требования к качеству применяемых авиационных масел, требуемых для обеспечения надежной работы в том числе маслосистем двигателей, подшипников опор роторов и других узлов. Одним из важных факторов снижения трения и износа современных газотурбинных двигателей является использование высококачественных масел с высоким уровнем противоизносных и антифрикционных свойств, позволяющих обеспечить работу двигателей при различных режимах смазки. В отечественной нормативно-технической документации противоизносные свойства авиационных масел оцениваются с помощью четырехшариковой машины трения (ЧМТ) по ГОСТ 9490, а антифрикционные свойства не учтены. Указанная машина трения имеет ряд недостатков. В этой связи авторами проведена оценка противоизносных и антифрикционных свойств отечественных авиационных масел с помощью универсального вибротрибометра, позволяющего исследовать эксплуатационные свойства масел при режимах, наиболее характерных для реальной эксплуатации авиационных двигателей, по сравнению с параметрами испытаний масел на четырехшариковой машиной трения. В отличие от ЧМТ в конструкции вибротрибометра используется схема контакта в паре трения «шарик – плоскость пластины». При этом на указанном приборе установлена термокамера, которая обеспечивает постоянный нагрев пары трения и испытуемых смазочных масел до требуемой температуры (от 0 до 150 ºС). По результатам испытаний установлено, что наилучшими противоизносными и антифрикционными свойствами обладает масло авиационное ИПМ-10, а с увеличением температуры испытаний масел происходит пропорциональное увеличение износа в паре трения «шарик – плоскость пластины»

Superconducting nanowire photon number resolving detector at telecom wavelength

The optical-to-electrical conversion, which is the basis of optical detectors, can be linear or nonlinear. When high sensitivities are needed single-photon detectors (SPDs) are used, which operate in a strongly nonlinear mode, their response being independent of the photon number. Nevertheless, photon-number resolving (PNR) detectors are needed, particularly in quantum optics, where n-photon states are routinely produced. In quantum communication, the PNR functionality is key to many protocols for establishing, swapping and measuring entanglement, and can be used to detect photon-number-splitting attacks. A linear detector with single-photon sensitivity can also be used for measuring a temporal waveform at extremely low light levels, e.g. in long-distance optical communications, fluorescence spectroscopy, optical time-domain reflectometry. We demonstrate here a PNR detector based on parallel superconducting nanowires and capable of counting up to 4 photons at telecommunication wavelengths, with ultralow dark count rate and high counting frequency