Highly polarized injection luminescence in forward-biased ferromagnetic-semiconductor junctions at low spin polarization of current

We consider electron tunneling from a nonmagnetic $n$-type semiconductor ($n$-S) into a ferromagnet (FM) through a very thin forward-biased Schottky barrier resulting in efficient extraction of electron spin from a thin $n$-S layer near FM-S interface at low spin polarization of the current. We show that this effect can be used for an efficient polarization radiation source in a heterostructure where the accumulated spin polarized electrons are injected from $n$-S and recombine with holes in a quantum well. The radiation polarization depends on a bias voltage applied to the FM-S junction.Comment: 4 pages, 2 figure

Automatic selection of a subset size at vector fields construction

An algorithm for selection of the size of a correlation kernel at displacement vector field construction by the method of digital image correlation has been proposed. The algorithm has been tested on simulated and experimental optical images having different texture. The influence of the correlation kernel size and image texture on nose immunity at determining displacements has been studied. It is shown that the proposed algorithm allows to find this size providing the minimum error when determination of displacements and estimation of deformation

The algorithm of crack and crack tip coordinates detection in optical images during fatigue test

An algorithm of crack detection during fatigue testing of materials, designed to automate the process of cyclic loading and tracking the crack tip, is proposed and tested. The ultimate goal of the study is aimed at controlling the displacements of the optical system with regard to the specimen under fatigue loading to ensure observation of the 'area of interest'. It is shown that the image region that contains the crack may be detected and positioned with an average error of 1.93%. In terms of determining the crack tip position, the algorithm provides the accuracy of its localization with the average error value of 56 pixels

Measurement Affecting Errors in Digital Image Correlation

Optical full-field measurement methods such as Digital Image Correlation (DIC) are increasingly used in the area of experimental mechanics. The reliability for each measurement technique depends on the knowledge of its uncertainty and the sources of errors of the results. The aim of this work is to systemize the sources of errors related to digital image correlation (DIC) technique applied to strain measurements. The paper is concluded by some suggestions proposed in order to minimize the errors

Application of Lucas-Kanade algorithm with weight coefficient bilateral filtration for the digital image correlation method

Application of bilateral filer weight coefficients for computing the weight function in Lucas-Kanade algorithm for optical flow determination is proposed. The obtained results based on processing different image types demonstrate the error reduction in optical flow determination. The approach to weight function parameters selection for bilateral filter is proposed and investigated

Algorithm for J-Integral Measurements by Digital Image Correlation

The work is devoted to the testing of the algorithm for calculating J-integral based on the construction of vector fields by digital image correlation (DIC) method. A comparative analysis of J-integral values calculated using DIC and instrumental data obtained in accordance with ASTM E 1820 "Standard Test Method for Measurement of Fracture Toughness" has made. It is shown that this approach can be used for cases when the standard technique for measuring the J-integral cannot be applied, or the standard technique does not allow achieving the required accuracy for the integral determination in local areas of the loaded material

Automatic selection of a subset size at vector fields construction

An algorithm for selection of the size of a correlation kernel at displacement vector field construction by the method of digital image correlation has been proposed. The algorithm has been tested on simulated and experimental optical images having different texture. The influence of the correlation kernel size and image texture on nose immunity at determining displacements has been studied. It is shown that the proposed algorithm allows to find this size providing the minimum error when determination of displacements and estimation of deformation

АППАРАТНО-ПРОГРАММНЫЙ КОМПЛЕКС ПРОЕКТИРОВАНИЯ ГИБРИДНЫХ ПОМЕХОПОДАВЛЯЮЩИХ ФИЛЬТРОВ

An algorithm and program, allowing to realize conception of providing of electromagnetic compatibility in the chains of power electronics on the basis of application of hybrid radiofrequency interference filter, is offered. The method of receipt of the required parameters of fading is improved on the basis of the industrial produced wares by introduction of «intellectual» link with the reconstructed parameters. The informative providing, allowing taking into account the possible range of rejection of parameters rationally to choose a producer and type of filter taking into account the ways of distribution of interferences and requirements to good on the whole is developed.Предложен алгоритм и программа, позволяющие реализовать концепцию обеспечения электромагнитной совместимости в цепях энергообеспечения, особенно звукотехнических систем, на основе применения гибридного помехоподавляющего фильтра. Усовершенствован метод получения требуемых параметров затухания на основе промышленно выпускаемых изделий путем введения «интеллектуального» звена с перестраиваемыми параметрами. Разработано информационное обеспечение, позволяющее с учетом возможного диапазона отклонения параметров рационально выбирать производителя и тип фильтра с учетом путей распространения помех и требований к изделию в целом.Предложен алгоритм и программа, позволяющие реализовать концепцию обеспечения электромагнитной совместимости в цепях энергообеспечения, особенно звукотехнических систем, на основе применения гибридного помехоподавляющего фильтра. Усовершенствован метод получения требуемых параметров затухания на основе промышленно выпускаемых изделий путем введения «интеллектуального» звена с перестраиваемыми параметрами. Разработано информационное обеспечение, позволяющее с учетом возможного диапазона отклонения параметров рационально выбирать производителя и тип фильтра с учетом путей распространения помех и требований к изделию в целом

Mycoviruses are common among different species of endophytic fungi of grasses

8 páginas, 1 tabla, 1 figuraA survey of mycoviruses was made in a collection of 103 isolates belonging to 53 different species of endophytic fungi of grasses. DsRNA elements were detected in isolates of 12 of the species analyzed. The banding characteristics and sizes of some of the dsRNA elements suggest that they might belong to previously described mycovirus families. The observed incidence (22.6%) indicates that the presence of mycoviruses could be common among species of this group of ubiquitous fungi.This research was financed by project AGL2005-02839 granted by the Spanish Ministry of Science and Education. We thank Drs. Robert Coutts and Beatríz R. Vázquez de Aldana for reviewing the manuscript.Peer reviewe