Transient Cherenkov radiation from an inhomogeneous string excited by an ultrashort laser pulse at superluminal velocity

An optical response of one-dimensional string made of dipoles with a periodically varying density excited by a spot of light moving along the string at the superluminal (sub-luminal) velocity is theoretically studied. The Cherenkov radiation in such system is rather unusual, possessing both transient and resonant character. We show that under certain conditions, in addition to the resonant Cherenkov peak another Doppler-like frequency appears in the radiation spectrum. Both linear (small-signal) and nonlinear regimes as well as different string topologies are considered.Comment: accepted to Phys. Rev.

REGULATORY ASPECTS OF AGRIBUSINESS ENTITIES DEVELOPMENT

The authors presents the system representation of the process of interaction between the state and the subjects of agricultural production, supplemented by the block of regulation of the development of large, medium and small agricultural farms. The methodical approach of determination of economic eciency of measures of the state it allows to take into account and use in the right direction the factors of inuence of exogenous impacts, which are dicult controlled by business. It is proposed to improve the mechanism of state support, to orient the expenses of budget expenditures on the formation of the nal result. The criteria of the nal result is proposed to supplement the indicator of social eect - the number of jobs created and additional budget revenue

THE DEVELOPMENT TRENDS OF REGIONAL AGRICULTURAL PRODUCTION

The problematic trends of the main factors of agricultural raw materials production have been considered. The high volatility of volume indicators, the lack of correlation between the profitability of business and product output have been noted. It has been concluded, that the current dynamics of cost indicators is largely determined by the market conditions of products and resources, and not by the processes of the producers themselves, the general trend of growth of profitability remains at low levels. Regional structural changes of branch production by types of products, the reasons of decrease in production of animal products have been shown. There difficulties with the production of forage crops, beef, pork, sunflower, lack of own funds, high accounts payable of producers have been noted. It has been proposed to increase the role of state participation in the creation of an effective business environment

Modeling the burnout of solid polydisperse fuel under the conditions of external heat transfer

A self-similar burnout mode of solid polydisperse fuel is considered taking into consideration heat transfer between fuel particles, gases, and combustion chamber walls. A polydisperse composition of fuel is taken into account by introducing particle distribution functions by radiuses obtained for the kinetic and diffusion combustion modes. Equations for calculating the temperatures of particles and gases are presented, which are written for particles average with respect to their distribution functions by radiuses taking into account the fuel burnout ratio. The proposed equations take into consideration the influence of fuel composition, air excess factor, and gas recirculation ratio. Calculated graphs depicting the variation of particle and gas temperatures, and the fuel burnout ratio are presented for an anthracite-fired boiler. © 2013 Pleiades Publishing, Inc

Formation and development of the processing industry in the AIC of the region

The theoretical grounding of the management system of animal feedingstuff milling of the region was performed. The facilities of animal feedingstuff milling are divided according to the degree of independence of business conducting and directions of sales of the products manufactured. The factors of the internal and external environment of the animal feedingstuff milling of the region were considered. The analysis was performed and the tendencies in the development of animal feedingstuff milling of the region and the system of its management were revealed; the directions of the development of animal feedingstuff milling of the agrarian region were grounded. The potential capacity of the regional market of animal feedingstuff for livestock breeding of the region was calculated. It was offered to form the body of economic management in the form of an independent legal entity bearing the responsibility for execution of the functions imposed on it to develop and implement the plan of development of animal feedingstuff milling – JSC Animal Feedingstuff Cluster of the Altai Territory.peer-reviewe

Comparison of Linear and Nonlinear Equalization for Ultra-High Capacity Spectral Superchannels

In ultra-high-speed (>400Gb/s per wavelength), high-spectral efficiency coherent optical communication systems using multi-carrier spectral superchannels, the maximum reach is severely limited due to linear and, foremost, nonlinear impairments. Hence, the implementation of advanced digital signal processing (DSP) techniques in optical transceivers is crucial for alleviating the impact of such impairments. However, the DSP performance improvement comes at the expense of increased cost and power consumption. Given that the computational complexity of the applied linear and nonlinear equalizers is the factor that determines the trade-off between the performance improvement and cost, in this study we provide an extended analysis on the computational complexity of various linear and nonlinear equalization approaches. First, we draw a complexity comparison between a conventional OFDM coherent receiver versus a filter-bank based OFDM receiver and it is shown that the latter provides significant complexity savings. Second, we present a comparison between the digital back-propagation split-step Fourier (DBP-SSF) method and the inverse Volterra series transfer function nonlinear equalizer (IVSTF-NLE) in terms of performance and computational complexity for a 32 Gbaud polarization multiplexed (PM)-16 quadrature amplitude modulation (QAM) OFDM superchannel

Аналитический расчет параметров потока в угловом теле при сверхзвуковых скоростях

A corner body represented by two intersecting wedges is used as a model to study an interaction of plane shock waves in space.With supersonic flow of such body, each wedge provokes forming a shock wave, and they are intersected and interact in space. There are two types of wedge-provoked shock wave interaction: regular and more complex – Mach's.The author of the article has investigated the possibility of one or another type of interaction of shock waves in the corner body. The type of interaction depends not only on the intersecting shock waves, but also on the position of the intersection line in space.The technique is based on analytical relations for oblique shock. For calculating is used a principle of the vector decomposition of running-in velocity into two components: one is directed along the line of intersection of shock waves, and the other lies in the plane of the normal line of intersection. Initial coordinate system is rotated so that one of its axes is directed along the line of intersection, and the two others lie in a plane perpendicular to the line of intersection. This is called a plane of calculation. In the calculation plane there is a normal component of the velocity, which is used as an initial. The flow structure in this plane is identical to two-dimensional interaction of shock waves.The type of interaction is determined by the two-dimensional calculation. The solution is reduced to finding the flow parameters on both sides of the tangential discontinuity. The solution is illustrated by the shock polar in coordinates:  a pressure ratio - flow deviation.The article presents a calculating diagram to determine the interaction type of shock waves.The article gives the downflow calculation results: interaction between the reflected shock wave and the wedge surface and other surfaces.Determining the type of interaction is necessary in calculation of such flows by numerical methods, since it allows proper defining the geometry of the computational domain. In addition, in the case of regular interaction the analytical formulas can be used to determine the reflected shock parameters thereby reducing the time of numeric calculations and increasing the accuracy. The developed algorithm can be used in designing the space input devices for high supersonic speed aircrafts.В качестве модели для изучения взаимодействия плоских скачков уплотнения в пространстве используется угловое тело, представляющее из себя два пересекающихся клина.При сверхзвуковом обтекании такого тела от каждого клина образуется скачок уплотнения, они пересекаются и взаимодействуют в пространстве. Возможны два типа взаимодействия скачков от клиньев: регулярное и более сложное – маховское.Автором статьи были исследованы возможности возникновения того или иного типа взаимодействия скачков уплотнения в угловом теле.  Тип взаимодействия зависит не только от пересекающихся скачков, но и от положения  в пространстве линии их пересечения.Методика основана на аналитических соотношениях для косого скачка уплотнения. Для расчета используется принцип разложения вектора набегающей скорости на две компоненты: одна направлена вдоль линии пересечения скачков уплотнения, другая лежит в плоскости нормальной линии пересечения. Исходная система координат поворачивается таким образом, что одна из осей направлена вдоль линии пересечения, а две другие  лежат в плоскости, перпендикулярной линии пересечения; эта плоскость называется расчетной. В расчетной плоскости лежит нормальная компонента скорости, которая используется как начальная. Структура течения в этой плоскости идентична двумерному взаимодействию скачков. Тип взаимодействия определяется по двумерному расчету. Решение сводится к нахождению параметров потока по обе стороны тангенциального разрыва. Решение  иллюстрируется  ударными полярами в координатах отношение давлений – отклонение потоков.Приводится расчетная диаграмма, по которой можно определить тип взаимодействия скачков.Приводятся результаты расчета вниз по течению: взаимодействие отраженного скачка уплотнения с поверхностью клина и с другими поверхностями.Определение типа взаимодействия скачков необходимо при расчете таких течений численными методами, так как это позволяет правильно задавать геометрию расчетной области. Кроме того, в случае регулярного взаимодействия параметры за отраженными скачками можно определить по аналитическим формулам, что сократит время численных расчетов и повысит точность. Разработанный алгоритм может использоваться при проектировании пространственного входного устройства для летательных аппаратов больших сверхзвуковых скоростей