Optical Spin Orientation in Strained Superlattices

Optical orientation in the strained semiconductor superlattices is investigated theoretically. The dependence of the features in spin-polarization spectra on the structure parameters is clarified. The value of polarization in the first polarization maximum in the SL structures is shown to grow with the splitting between the hh- and lh- states of the valence band, the joint strain and confinement effects on the hh1- lh1 splitting being strongly influenced by the tunneling in the barriers. In strained structures with high barriers for the holes initial polarization can exceed 95 %. Calculated polarization spectra are close to the experimental spectra of polarized electron emission.Comment: 20 pages, 8 figure

Frequency and Magnetic Field Dependence of the Skin Depth in Co-rich Soft Magnetic Microwires

We studied giant magnetoimpedance (GMI) effect in magnetically soft amorphous Co-rich microwires in the extended frequency range. From obtained experimentally dependences of GMI ratio on magnetic field and different frequencies we estimated the penetration depth and its dependence on applied magnetic field and frequenc

Проблемы инновационного контроля успешности студентов по гуманитарным дисциплинам

Авторами аналізується процес організації інноваційного контролю навчання і самостійної роботи студентів ВНЗ з гуманітарних дисциплін, відповідно до вимог Болонського процесу. Оцінюються різні підходи, напрями і методи оптимізації цієї діяльності у ВНЗ. Аналізуються різні технології контролю навчання студентів у модульно-рейтинговій системі.Authors analyze the process of organizing of the innovational control in studying of humanitarian disciplined students according to up-to-date Bologna Process standards; value different approaches, directions and optimization methods of one in Ukrainian universities. Also different technologies of success in studies of students controlling according to module-rating system are analyzed.Авторами анализируется процесс организации инновационного контроля обучения и самостоятельной работы студентов вузов с гуманитарных дисциплин, в соответствии с требованиями Болонского процесса. Оцениваются разные подходы, направления и методы оптимизации этой деятельности в вузах. Анализируются разные технологии контроля обучения студентов в модульно-рейтинговой системе

Реалии и противоречия партийного лидерства в украинском обществе: политологический аспект

Обговорюється проблема партійного лідерства як процесу взаємодії між партіями і громадянами. Аналізується процес розвитку партійного лідерства в Україні і пропонується нова модель типології партійного лідера.The article is dedicated to the discussion of the problem concerning the party leadership as the process of the interaction of people. The development of the party leadership in Ukraine is analyzed and the new model of the typology of a Party leader is proposed.Обсуждается проблема партийного лидерства как процесса взаимодействия между партиями и гражданами. Анализируется процесс развития партийного лидерства в Украине и предлагается новая модель типологии партийного лидера

Radio flux variations of the quasar J1159+2914 (S5 1156+295) in 2010–2013

© 2014, Pleiades Publishing, Ltd. Results of the observations of the blazar J1159+2914 (S1156+295) in 2010–2013 are reported. The observations were carried out on the RATAN-600 radio telescope (Special Astrophysical Observatory, Russian Academy of Sciences) at 4.85, 7.7, 11.1, and 21.7 GHz and the 32-m Zelenchuk and Badary radio telescopes of the Quasar-KVO Complex (Institute of Applied Astronomy, Russian Academy of Sciences) at 4.85 and 8.57 GHz. A flare peaked in August 2010, after which the flux density decreased monotonically at all studied frequencies. Variability on a timescale of 7 days was detected at 7.7 and 11.1 GHz near the flare maximum. The delay in the maximum at 7.7 GHz relative to the maximum at 11.1 GHz was 1.5 d, implying a Lorentz factor γ = 55 and angle of the jet to the line of sight θ ≈ 2° since mid-2011. Searches for intraday variability (IDV) were undertaken by the 32-m telescopes, mostly since mid-2011. Intraday variability was confidently detected only at the Badary station on November 10–11, 2012 at 4.85 GHz: the IDV timescale was τacf = 6 h, the modulation index was m = 1.4%, and the flux density of the variable component was Svar = 126 mJy

Towards eliminating friction and wear in plain bearings operating without lubrication

Plain bearings, renowned for their versatility and simplicity, are extensively utilized in engineering design across various industries involving moving parts. Lubrication is vital to the functioning of these bearings, yet their usage is inhibited under dynamic load conditions, or at elevated or reduced temperatures due to this dependency on lubrication. This study introduces an innovative method to significantly mitigate friction and wear in plain bearings operating without lubrication. The plain bearings were constructed from steel–bronze pairs, where the steel shafts were alloyed with bismuth oxide via short-pulse laser treatment. MnO2 was utilized as a carrier to incorporate the bismuth oxide into the surface layers of the steel. Insights from transmission electron microscopy and X-ray photoelectron spectroscopy revealed a highly non-equilibrium state of matter, unattainable through conventional engineering methods. The tribological performance of the modified steel disks was assessed via a block-on-ring sliding test, demonstrating superior wear and friction performance without lubrication, as well as an ultra-low coefficient of friction. Remarkably, the modified friction pairs remained functional after 200 km of linear sliding at a load of 250 N (12.5 MPa) and a sliding speed of 9 m/s. To substantiate the technique’s viability, we tested the performance of an internal combustion engine turbocharger fitted with a modified steel shaft. The turbocharger’s performance validated the long-term effectiveness of the steel–bronze coupling operating without lubrication at 75,000 rpm. The simplicity and resilience of this technique for modifying steel–bronze pairs offer a ground-breaking and promising approach for a wide range of applications. © 2023, Springer Nature Limited.Russian Science Foundation, RSF: 19-79-20012This study is financially supported by Russian Science Foundation, project No. 19-79-20012