Shot noise and Coulomb blockade of Andreev reflection

We derive low energy effective action for a short coherent conductor between normal (N) and superconducting (S) reservoirs. We evaluate interaction correction $\delta G$ to Andreev conductance and demonstrate a close relation between Coulomb effects and shot noise in NS systems. In the diffusive limit doubling of both shot noise power and charge of the carriers yields $|\delta G|$ four times bigger than in the normal case. Our predictions can be directly tested in future experiments.Comment: 4 pages, 2 figure

Fluctuations of the Josephson current and electron-electron interactions in superconducting weak links

We derive a microscopic effective action for superconducting contacts with arbitrary transmission distribution of conducting channels. Provided fluctuations of the Josephson phase remain sufficiently small our formalism allows to fully describe fluctuation and interaction effects in such systems. As compared to the well studied tunneling limit our analysis yields a number of qualitatively new features which occur due to the presence of subgap Andreev bound states in the system. We investigate the equilibrium supercurrent noise and evaluate the electron-electron interaction correction to the Josephson current across superconducting contacts. At T=0 this correction is found to vanish for fully transparent contacts indicating the absence of Coulomb effects in this limit.Comment: 12 pages, 4 figure

METHODS FOR MANAGING INTANGIBLE ASSETS AND ECOMMERCE RESOURCES: SYSTEMATIC REVIEW

Objective: The study aims at classifying and supplementing general and special methods for managing intangible assets and eCommerce resources. The present stage of management science is characterized by an insufficient number and incomplete nature of the existing studies on the structure of methods for managing intangible assets and eCommerce resources, which is mainly due to the relative novelty of the Internet environment and its management. The challenge of solving this issue is the intangibility of the management object under study (intangible assets and resources) and the intangibility of the management environment (Internet environment), which makes management in such conditions more difficult. Methods: When preparing this article, we used qualitative research methods, including grouping sets of homogeneous management methods, systematizing such methods according to homogeneous features, comparing different methods with each other, and generalizing the obtained groups of methods to draw conclusions and recommendations. When grouping methods for managing intangible assets and eCommerce resources, we took the classification according to a functional attribute as the basis. Results: As a result of the study, the authors have revealed that the management of intangible assets and eCommerce resources requires the full range of general management methods (planning, organizational, evaluation, accounting, analytical, motivational, control, and coordination methods), special methods for managing intangible assets and resources (identification, visualization, and security methods), as well as specific methods for managing intangible assets and resources in the Internet environment (online methods). Conclusion: Based on the study results, it has been concluded that online management methods are most actively developing in the modern market, and in the near future the importance of these methods will increase. The novelty of the study is to determine the presence and composition of previously unexplored groups of management methods applied to intangible assets and eCommerce resources

SHG in γ-Ga2S3 powder

We report results on comparative study of SHG in powder of promising nonlinear γ-Ga2S3 crystal. Digallium trisulfide powders with particle size from 20 μm to 500 μm were tested in comparison with powders of well-known LBO, BBO, KABO, KDP, and LN crystals under the pumping by 7 ns 1064 Nd:YAG laser. Laser-induced damage threshold of different powder fractions were determined. The γ-Ga2S3 shown high damage threshold and large SHG intensity: 56 times to that in LBO powder, 15 in BBO, 50 in KABO, 67 in KDP, and 3 in LN (for particle size: 20–50 μm), that renders it amongst the most promising crystal for frequency conversion of high-intense nanosecond radiation of near-IR lasers by optical rectification technique

Сравнительный анализ аналитического и численного решения задачи о термокапиллярной конвекции в прямоугольном канале

The paper compares the exact solution of one-dimensional and two-dimensional stationary convective flow equations with a free boundary for a flat liquid channel. Constant temperature gradient is set on the bottom solid wall. On the upper free boundary the surface tension coefficient is linearly dependent on temperature. Zero heat flux and velocities are set on the side walls of the two-dimensional problem. The deviation of the one-dimensional exact solution is determined for different aspect ratio and Marangoni numberВ работе выполнено сравнение точного решения уравнений одномерного и двумерного стационарного конвективного течения со свободной границей для плоского горизонтального слоя жидкости с постоянным градиентом температуры на нижней границе слоя и свободной верхней границей с коэффициентом поверхностного натяжения, линейно зависящим от температуры. Определена погрешность одномерного точного решения при различной степени стеснения поток

Повышение эффективности судовых МОД охлаждением наддувочного воздуха в термотрансформаторе

Андреев, А. А. Повышение эффективности судовых МОД охлаждением наддувочного воздуха в термотрансформаторе = Improving the efficiency of marine low-speed engine by cooling charging air in thermotransformer / А. А. Андреев, Н. Б. Андреева // Зб. наук. пр. НУК. – Миколаїв : НУК, 2015. – № 5 (461) – С. 18–23.Доведено можливiсть встановлення тепловикористовуючої установки охолодження в машинному вiддiленнi судна. Як термотрансформатор розглянуто тепловикористовуючу ежекторну холодильну машину, що утилiзує теплоту наддувного повiтря МОД. Показано залежнiсть ефективностi МОД вiд температури наддувного повiтря в суднових умовах, а також доцiльнiсть утилiзацiї теплоти. Розраховано термiн окупностi тепловикористовуючої системи охолодження наддувного повiтря для МОД.The possibility of installing of waste heat cooling system in a engine room of a transport vessel was proved. The waste heat recovery ejector cooling machine utilizing the heat of scavenge air as an example of thermotransformer is shown. The dependence of the efficiency of the two-stroke low-speed diesel on the temperature of the scavenge air in the marine environment and the feasibility of heat recovery are shown. Payback of waste heat cooling system for the two-stroke low-speed diesel was calculated.Доказана возможность установки теплоиспользующей установки охлаждения в машинном отделении судна. Как термотрансформатор рассмотрена теплоиспользующая эжекторная холодильная машина, которая утилизирует теплоту наддувочного воздуха МОД. Показана зависимость эффективности МОД от температуры наддувочного воздуха в судовых условиях, а также целесообразность утилизации теплоты. Рассчитан срок окупаемости теплоиспользующей системы охлаждения наддувочного воздуха для МОД

Radiophotonic method for instantaneous frequency measurement based on principles of “frequency-amplitude” conversion in Fiber Bragg grating and additional frequency separation

This article describes the design principles of optoelectronic system (OES) for instantaneous frequency measurement (IFM) of microwave signals based on the use of amplitude-phase modulation conversion of single optical carrier into symmetrical dual-frequency signal for additional frequency separation, its modulation by unknown frequency and subsequent “frequency-amplitude” measurement conversion in Fiber Bragg Grating (FBG) with Gaussian reflection profile. Such approach allows increasing of measurement resolution at low frequencies

Identification of Patterns in the Structural and Phase Composition of the Doping Alloy Derived From Metallurgical Waste Processing

This paper reports a study into the structural-phase composition of the doping alloy made by processing metallurgical anthropogenic waste involving reduction smelting. This is required for determining the technological parameters that ensure an increase in the level of extraction of target elements during the processing of anthropogenic waste and for the further use of the doping alloy. It was revealed that the phase composition of the doping alloy manifested a solid solution of the doping elements and carbon in α-Fe. Cementite Fe3C and silicides Fe5Si3, FeSi, and FeSi2 were also identified. In this case, the doping elements were more likely to act as substitution atoms. It has been determined that the microstructure of the alloy consisted of several phases of different shapes and contents of the basic doping elements. Sites with an elevated iron level of up to 95.87 % by weight in the composition could be represented by the solid solution phase of the doping elements and carbon in α-Fe. The sites with a relatively high (% by weight) content of carbon (0.83‒2.17) and doping elements ‒ W, up to 39.41; Mo, up to 26.17; V, to 31.42; Cr, to 9.15 ‒ were apparently of a carbide nature. The sites with a silicon content of 0.43‒0.76 % by weight likely included silicide compounds. The alloy's characteristics make it possible to smelt steel grades without strict carbon restrictions, replacing some of the standard ferroalloys. Neither phases nor compounds with a relatively high propensity for sublimation were identified in the material produced. Therefore, there is no need to provide conditions to prevent evaporation and loss in the gas phase of the doping elements. That could increase the degree of extraction of the doping element

Establishing Patterns of the Structural-phase Transformations During the Reduction of Tungsten-containing Ore Concentrate with Carbon

This paper reports a study into the phase composition and microstructure of tungsten ore concentrate after carbon-thermal reduction at different O:C ratios in the charge. This is required for determining those indicators that reduce tungsten loss through the sublimation of oxide compounds when processing ore concentrates, as well as when using reduced tungsten-containing doping additives. The study results have established that the reduced tungsten concentrate at the O:C ratio in the charge within the interval of 1.33‒2.30 contained the phases of W, W2C C, C, WO2. The microstructure demonstrated a spongy and disordered character. Together with W, the Mo, Si, Ca, Al impurities were present in the reduced products. The main elements identified at the sites studied had the following limiting content, % by weight: O – 5.01–17.32; C – 0.84–4.23; W – 61.21–86.78; Mo – 1.57–7.51; Si – 2.07–9.06; Ca – 1.34–11.30; Al – 0.27–0.40. The micro-inclusions at the examined surface areas acquired different complex shapes. There were traces of the process of caking between the particles. The analysis of the resulting data has shown that the most preferred ratio of O:C in the charge was 1.65. In this case, there is no lack of carbon and there is a predominance of W in the phase composition with a relatively little manifestation of the W2C phases, carbon, as well as the residual part of WO2. The post-reduction of the oxide component would occur during the doping process. The sponge structure contributes to a higher dissolution rate compared to standard tungsten ferroalloys. Lack of compounds with a relatively high propensity for sublimation does not require any special conditions to prevent the loss of tungsten in the gas phase, which increases the degree of assimilation of the target elemen