Short-Range Order in Fe-Rich Fe-Cr Alloys as Revealed by M\"ossbauer Spectroscopy

Distribution of Cr atoms in Fe_{100-x}Cr_x alloys with x \le 25 within the first two coordination shells, 1NN-2NN, around probe 57Fe atoms was studied by means of the M\"ossbauer Spectroscopy. Clear evidence was found that the distribution is characteristic of a given atomic configuration. Only the configurations with Cr atoms situated in 2NN exhibit a quiasi-random distribution, while those with Cr atoms present in 1NN shell and those with Cr atoms in both shells is evidently not random showing clastering or anticlastering features. These findings are novel and much more complete than the up-to-date knowledge according to which there is an inversion of the short-range order parameter at x = 11. The inversion in the present study was found only for the configuration with one Cr atom in 1NN. On average, Cr atoms are distributed almost randomly within the 1NN-2NN volume for x \eq ~10, and do cluster for larger x.Comment: 4 pages and 4 figure

Relation between the X-ray and Optical Luminosities in Binary Systems with Accreting Nonmagnetic White Dwarfs

We investigate the relation between the optical (g-band) and X-ray (0.5-10 keV) luminosities of accreting nonmagnetic white dwarfs. According to the present-day counts of the populations of star systems in our Galaxy, these systems have the highest space density among the close binary systems with white dwarfs. We show that the dependence of the optical luminosity of accreting white dwarfs on their X-ray luminosity forms a fairly narrow one-parameter curve. The typical half-width of this curve does not exceed 0.2-0.3 dex in optical and X-ray luminosities, which is essentially consistent with the amplitude of the aperiodic flux variability for these objects. At X-ray luminosities Lx~1e32 erg/sec or lower, the optical g-band luminosity of the accretion flow is shown to be related to its X-ray luminosity by a factor ~2-3. At even lower X-ray luminosities (Lx~1e30 erg/sec), the contribution from the photosphere of the white dwarf begins to dominate in the optical spectrum of the binary system and its optical brightness does not drop below Mg~13-14. Using the latter fact, we show that in current and planned X-ray sky surveys, the family of accreting nonmagnetic white dwarfs can be completely identified to the distance determined by the sensitivity of an optical sky survey in this region. For the Sloan Digital Sky Survey (SDSS) with a limiting sensitivity m_g~22.5, this distance is ~400-600 pcComment: 7 pages, 3 figures, published in Astronomy Letter

A non-perturbative proof of Bertrand's theorem

We discuss an alternative non-perturbative proof of Bertrand's theorem that leads in a concise way directly to the two allowed fields: the newtonian and the isotropic harmonic oscillator central fields.Comment: Latex file plus one eps figur

Comparative analysis of design events (the case lighting case of the murder of Boris Nemtsov resource "RUSSIATODAY")

The work is devoted to the methods of constructing the events in the text. For the analysis of the materials were chosen Russian international multilingual information service «Russia today», which relate to «the murder of Boris Nemtsov» directly or indirectly. The empirical base of our research includes 166 materials (text, audio and video). Chronological scope of the study – from 27th February 2015 to 13th January 2016. The texts are presented in two languages – russian (98 materials) and english (68 stories).Работа посвящена способам конструирования событий в тексте. Для анализа были выбраны материалы российской международной многоязычной информационной службы «Russia today», которые касаются убийства Бориса Немцова прямо или косвенно. Эмпирическая база нашего исследования насчитывает 166 материалов (печатных, аудио и видео). Хронологические рамки исследования — с 27 февраля 2015 года по 13 января 2016 года. Тексты представлены на двух языках — русском (98 материалов) и английском (68 материалов). Цель исследования — найти различия в конструировании события (убийство Бориса Немцова) всемирной телевизионной службой "Russiatoday"для русскоговорящей и иноязычной аудитории

Моделирование сборочных единиц и технологии сборки изделий в приборостроении

В роботі розглядаються питання створення математичної моделі виробу з метою автоматизації технології механоскладальних робіт. При цьому розглядаються функціональні зв’язки між параметрами конструкції і порядком створення виробу.In work the question of creation of mathematical model of a product is considered with the purpose of automation of technology of machine-assembling works. Thus functional communications between parameters of a design and the order of creation of a product are considered.В работе рассматривается вопрос создания математической модели изделия с целью автоматизации технологии механосборочных работ. При этом рассматриваются функциональные связи между параметрами конструкции и порядком создания изделия

Reconstrucción tridimensional de la musculatura F-actina de Dorvillea kastjani (Dorvilleidae: Polychaeta) por medio de marcado con phalloidina y cLSM

This paper is part of a series investigating the muscular architecture of various “Polychaeta”, aiming to ascertain the presence of circular muscles in the body wall, which have recently been thought to be lacking more often than hitherto known. The F-actin muscular subset of Dorvillea kastjani was labelled with phalloidin and the architecture three-dimensionally reconstructed by means of confocal laser scanning microscopy. Three pairs of longitudinal, two transverse and numerous radial muscles ensure shape and flexibility of the prostomium. Mobility of the sub-biramous parapodia and their chaetae is achieved by seven different muscle types. The body wall contains transverse and bracing muscles and in total five longitudinal muscle strands: two dorsolateral, two ventral and one ventromedial. Numerous transverse fibres extend from the dorsal side peripherally and ventrally and become concentrated into six or seven pairs of bundles per segment on the ventral side. They terminate before reaching the midline, leaving a gap of only a few micrometres between them. Within the intersegmental furrows these fibres form complete rings in a supralongitudinal postion. Thus, true circular fibres exist in D. kastjani but are weakly developed.Este trabajo forma parte de una serie de trabajos que investigan la arquitectura muscular de diferentes especies de Poliquetos con el objetivo de comprobar la presencia de musculatura circular en su cuerpo; recientemente se piensa que dicha musculatura podría estar ausente más a menudo de lo hasta ahora pensado. La musculatura F-actina de Dorvillea kastjani fue marcada con phalloidina y su arquitectura reconstruida tridimensionalmente por medio de microscopia de scanning laser confocal. Tres pares longitudinales, dos tranversales y numerosos músculos radiales aseguran la flexibilidad y la forma del prostómio. La mobilidad de los parápodos sub-biramios y sus quetas se obtiene gracias a siete diferentes tipos de músculos. La cavidad del cuerpo contiene musculos tranversales y diagonales y en total cinco ramas de músculos longitudinales: dos dorsolaterales, dos ventrales y una medioventral. Numerosas fibras transversales se extienden desde la zona dorsal periféricamente y centralmente y se concentran en seis o siete pares de paquetes por segmento en la cara ventral. Estos terminan antes de alcanzar la línea central dejando un vacio de unas micras entre ellos. Entre los surcos entre segmentos, las fibras forman anillos completos en una posición supralongitudinal. Además, verdaderas fibras circulares existen en Dorvillea kastjani pero están débilmente desarrolladas. &nbsp