Create modular hpf boards for educational research with installation NI ELVIS II

Настоящая статья посвящена разработке модульных плат фильтров верхних частот и исследованию их характеристик. Создание модульных плат проводилось в несколько этапов: расчет элементов, моделирование ФВЧ, подбор радиоэлементов в соответствии с расчетами и монтаж фильтров на печатные платы. Для создания модульных плат был выбран ФВЧ Чебышева, поскольку отличительной особенностью этих фильтров является более крутой спад амплитудно-частотной характеристики (АЧХ) и существенные пульсации амплитудно-частотной характеристики на частотах полос пропускания и подавления, чем у фильтров других типов. Создание модульных плат свелось к решению поставленных задач, а именно произвести расчет элементов, смоделировать фильтры в ПО Multisim, подобрать радиоэлементы в соответствии с расчетами и произвести монтаж фильтров на печатные платы. Таким образом было создано восемь модульных плат ФВЧ с разными частотами среза. По итогу работы модульные платы были проверены на учебной установке NI ELVIS II путем снятия АЧХ фильтров. Снятые характеристики соответствовали теоретическим расчетам.This article is devoted to the development of modular circuit boards of high pass filters and study their characteristics. Creating a modular boards conducted in several stages: the calculation of the elements, modeling HPF, selection of radio in accordance with the calculations and installation of filters on printed circuit boards. To create a modular boards Chebyshev HPF has been selected as a distinctive feature of these filters is a steeper decline in the amplitude-frequency characteristic (AFC) and substantial ripple frequency response at the frequencies and bandwidths suppression than the other types of filters. Creating a modular boards reduced to the solution of tasks, namely to calculate the elements, to simulate filters in the software Multisim, pick up the radioactive elements in accordance with the calculations and produce the installation of filters on printed circuit boards. Thus was created the HPF eight modular boards with different cutoff frequencies. The outcome of modular boards was tested for learning installing NI ELVIS II by removing the filter frequency response. Previous theoretical calculations matched characteristics

Surface softening in metal-ceramic sliding contacts: An experimental and numerical investigation

This study investigates the tribolayer properties at the interface of ceramic/metal (i.e., WC/W) sliding contacts using various experimental approaches and classical atomistic simulations. Experimentally, nanoindentation and micropillar compression tests, as well as adhesion mapping by means of atomic force microscopy, are used to evaluate the strength of tungsten?carbon tribolayers. To capture the influence of environmental conditions, a detailed chemical and structural analysis is performed on the worn surfaces by means of XPS mapping and depth profiling along with transmission electron microscopy of the debris particles. Experimentally, the results indicate a decrease in hardness and modulus of the worn surface compared to the unworn one. Atomistic simulations of nanoindentation on deformed and undeformed specimens are used to probe the strength of the WC tribolayer and despite the fact that the simulations do not include oxygen, the simulations correlate well with the experiments on deformed and undeformed surfaces, where the difference in behavior is attributed to the bonding and structural differences of amorphous and crystalline W-C. Adhesion mapping indicates a decrease in surface adhesion, which based on chemical analysis is attributed to surface passivation

Roadmap on dynamics of molecules and clusters in the gas phase

This roadmap article highlights recent advances, challenges and future prospects in studies of the dynamics of molecules and clusters in the gas phase. It comprises nineteen contributions by scientists with leading expertise in complementary experimental and theoretical techniques to probe the dynamics on timescales spanning twenty order of magnitudes, from attoseconds to minutes and beyond, and for systems ranging in complexity from the smallest (diatomic) molecules to clusters and nanoparticles. Combining some of these techniques opens up new avenues to unravel hitherto unexplored reaction pathways and mechanisms, and to establish their significance in, e.g. radiotherapy and radiation damage on the nanoscale, astrophysics, astrochemistry and atmospheric science