Flexure hinge having a rectangular cross section is often used as a basic construction element in micropositioning systems. The article deals with known theoretical relations for computing its mechanical properties. Practical limits of the maximal angular deflection of flexure hinges made from different materials and different dimensions were determined experimentally.
In radiometric measurement of the object temperature, in measurement and evaluation of heat escape from buildings we meet with materials, which can be characterised as transparent or semitransparent. One of them is glass. The objective of the present article is to analyse glass features, including emissivity in dependence to wavelength and temperature and also the thermal transmissivity of glass. and Pri bezkontaktných meraniach teploty objektov, pri meraní a vyhodnotení úniku tepla z budov sa stretávame s materiálmi, ktoré možno označiť ako priezračné alebo polopriepustné. Jedným z bežne používaných materiálov je sklo. V príspevku sa pokúšame analyzovať vlastnosti skla, jeho emisivitu v závislosti na vlnovej dĺžke a teplote.
This article deals with the properties of superconductive materials and their practical use in applications for lossless transmission of energy. Parameters of an YBa2 Cu3 Oy superconducting disk were investigated by means of SQUID and vibrating sample magnetometers. and Tento článek se zabývá vlastnostmi supravodivých látek a jejich praktickou využitelností v aplikacích pro bezeztrátový přenos energie. V rámci měření byly zkoumány parametry supravodivého disku YBa2 Cu3 Oy . K měření bylo využito skvidového a vibračního magnetometru.
Článek shrnuje nejvýznamnější výsledky studia vlastností látek při působení extrémně vyokých tlaků posledních dvou až tří desetiletí. Přes zřejmou experimentální náročnost studia bylo takovým tlakům v uplynulých letech vystaveno velmi široké spekturm látek - od nejjednodušších chemických prvků až po složité biologické materiály. Pojednáváme zde jak o fundamentálních aspektech výzkumu silně stlačených látek, tak o jeho aplikacích v různých vědních oborech - od planetologie až k potravinářství., The short review collects the most important results, from up to the last three decades, on the study of properties of extremely compressed matters. Despite the evident complexities of high pressure experiments, a very wide spectrum of materials have been subjected to extreme compression - starting from light chemical elements up to very complex biological compounds. This review deals with fundamental aspects of the studies as well as their application in different domains - from planetology to food science., Jiří Kamarád., and Obsahuje seznam literatury
((Introduction) We present the first results of a statistical study on the milliarcsec structure in a complete sample of active radio galaxies. Many works have been published on properties of VLBI cores in quasars, but no similar studies have been carried on for galaxies.
We adopted a 2-stage strategy for the observations. As a first step, we took a snapshot of all the selected sources, in,order to have an indication on the size and flux of the milliarcsecond component. We present here these first observations. As a second stage, we pian to map with better sensitivity and u-v coverage all the detected sources.
The purpose of this work was to detect groundwater pollution and to identify the conditions of soil and groundwater near the coal waste disposal "Panewniki" Halemba-Wirek Coal Mine using geoelectrical measurements. The firs t applied method was the VLF (Very Low Frequency) technique. This method, using military signals, allowed to perform the in-phase and the quadrature maps. Data were collected from four study areas located near the coal waste dump. Observed anomalies on both maps for each area showed places with different conductivity al lowed to detect the contaminated and uncontaminated zones. The VLF survey indicated that the contamination occurs in the eastern part of study area and is characterized by positive values of both measured electrical fields (the in-phase and the quadrature components). After preliminary contaminated zones were recognized using VLF met hod, an electrical imaging meth od was applied. Two electrical imaging profiles were carried out near the waste dump. The measurements a llowed to create the geoele ctrical model of surrounding area and to investigate the leachate plume. The electrical imaging showed that the greatest pollution occur in the area immediately adjacent to the coal waste what is confirmed by VL F survey. Based on the geological and ge ophysical knowledge from archives and on present researches, the contaminated aquifer with electrical resistivity of 5 to 15 Ω m deposited at depths of 3 to 7 m was found., Arlena Kowalska, Marta Kondracka and Maciej Jan Mendecki., and Obsahuje bibliografické odkazy
Vlha pestrá (Merops apiaster) je teplomilný ptačí druh uzpůsobený k lovu hmyzu. Proto patří k obyvatelům převážně subtropických a tropických oblastí, ale v opakovaných vlnách osídlovala i různá místa střední Evropy. Postupná expanze druhu probíhá i v České republice. Článek popisuje možnosti podpory hnízdění vlhy pestré na příkladu mokřadu Betlém na jižní Moravě., Merops apiaster is a termophilic insectivorous bird species. Hence it primarily inhabits subtropical and tropical regions, but it has also repeatedly settled in various Central European sites. The species is also gradually expanding in the Czech Republic. This article describes the possibility of supporting bee-eater nesting based on the example of the Betlém wetlands in southern Moravia., and Miroslav Šebela.