Transparentní keramika se v laserové technice využívá jako matrice aktivních laserových prostředí vysokovýkonových laserů, kde se začala prosazovat od začátku milénia. Díky svým jedinečným vlastnostem je atraktivní alternativou monokrystalů a skel, kdy nachází využití v široké škále oborů a aplikací zahrnujících optiku, vojenství, medicínu, detektory záření a další., Transparent ceramics have been used as matrices for laser gain media of high power lasers since the beginning of this millennium. Thanks to its unique qualities it has become an attractive alternative to glasses and single crystals, finding applications in the field of optics, defence, medical facilities, radiation detectors and many others., Samuel Paul David, Petr Navrátil, Martin Hanuš, Venkatesan Jambunathan, Martin Divoký, Antonio Lucianetti, Tomáš Mocek., and Obsahuje bibliografické odkazy
Under normal conditions, electrons are accelerated by electric fields and decelerated by collision processes. After some time, a stable equilibrium between these two processes is achieved and electrons drift with constant speed against the field direction. Such a scheme is called the ohmic regime. At higher speeds or electric fields, the situation may be completely different. Collisions may not be able to compensate for electron acceleration and electrons attain the so called runaway mode. Runaway electrons are detected in the Earth’s magnetosphere during storms, in the solar plasma, and also in laboratory plasmas and in many plasma technologies., Petr Kulhánek., and Obsahuje bibliografii
Výzkum fyziky ubíhajících elektronů se v posledních letech stal jednou z prioritních oblastí výzkumu na tokamacích. V rámci konsorcia EUROfusion, které koordinuje výzkum termojaderné fúze v Evropě, byl náš tým na tokamatu COMPASS v Ústavu fyziky plazmatu AV ČR, v. v. i., před šesti lety vyzván k zařazení studia ubíhajících elektronů do experimentálního programu. Tento článek shrnuje fyzikální motivaci k uvedenému výzkumu, dosažené znalosti a také hlavní výsledky, kterými v tomto směru náš tým přispívá k jistějšímu zvládnutí termojaderného provozu prvních fúzních reaktorů, včetně zařízení ITER., Research in the physics of runaway electrons has become one of the most important fields in current tokamak science. In the framework of the EUROfusion consortium, which coordinates thermonuclear fusion research in Europe, the Institute of Plasma Physics of the CAS was invited, from 2014, to introduce a runaway electron study into the experimental programme of the COMPASS tokamak. This article summarises the motivation for runaway electron research, the achieved knowledge, and also the main results of our team, which may contribute to yet safer thermonuclear operation of the first fusion reactors, including the ITER facility., Jan Mlynář, Jakub Čaloud, Ondřej Ficker, Eva Macúšová, Jaroslav Čeřovský., and Obsahuje bibliografické odkazy
Díky pokrokům v experimentální manipulaci s mikroskopickými systémy zažíváme v dnešní době žeň nových objevů ve výzkumu tepelných motorů. Získané výsledky ukazují, jak konstruovat tepelné motory pracující při maximální dovolené termodynamické účinnosti dané účinností Carnotova cyklu a dodávající nenulový a stabilní výkon, což je ve standardních učebnicích termodynamiky považováno za nemožné., The recent advent of novel micro-manipulation techniques has harvested many new results in the field of heat engines. It is now possible to construct heat engines operating at the maximum allowable thermodynamic efficiency determined by the Carnot efficiency and delivering non-zero stable output power, something which is considered impossible in standard thermodynamics textbooks., Viktor Holubec, Artem Ryabov., and Obsahuje bibliografické odkazy
In the present text I have attempted to describe the profession of elementary school teacher and the changes it underwent in the last quarter of the 18th century. At that time, the education of the majority of children between the ages of six and twelve or thirteen was mostly in the hands of village schoolmasters, and these are my primary focus. Following the reform of the education system by Maria Teresa, teachers in Bohemia and Moravia were trained predominantly in what were known as preparanda at the Normal School in Prague. Their training differed from that of their predecessors in that their knowledge was now tested in examinations, with greater emphasis on teaching methods and closer supervision. Drawing on lists of teacher training graduates and other sources, I have analysed how many graduated every year and under what conditions, what textbooks they later used in the classroom, and the official view of pedagogy at that time. From those lists I was able to conclude that graduates who only spoke Czech ended up teaching only in small Czech-medium village schools. By looking at certain individual teachers more closely (such as the composer Jakub Jan Ryba, the pastor Tomáš Juren and several members of the Vlach family of teachers from Boleslav), my aim was to describe in outline the career of these "Czech" village schoolmasters, their motivation, level of knowledge, and deduce what they probably taught. From 1787 on, they were subject to inspection by regional school commissioners. I focussed on the first sixteen of these (one for each region), noting in particular how they were selected, their duties and aims. For it is they who were the guarantors of the new school system and the disseminators of the new thinking.As a result of the reforms, mandatory training and more exacting standards, elementary school teachers were able to improve their social standing and prestige., Michal Kneblík., and Obsahuje bibliografické odkazy
As servants of their church community, teachers had to spend much of their time on activities that today we might consider secondary - tasks relating to their ancillary duties as cantor, organist or verger. But in rural communities the teachers, alongside the priests, were often the only educated men in the parish and played a not inconsiderable role in the early stages of the national revival movement. The school reforms passed in 18th century Hungary opened the way for teachers - even those in elementary schools - to improve their social standing and prestige, on condition they fulfilled certain expectations as formulated in the basic reform programme, Ratio educationis (1777). Our paper examines the new types of school (normal, preparatory) that offered teachers better chances of social advancement and public acceptance. Drawing on case studies of teachers in several schools, it documents how they managed to meet the demands made on them while still pursuing and realizing their own ambitions., Eva Kowalská., and Obsahuje bibliografické odkazy
Ultrakrátké světelné pulzy, tedy pulzy pikosekundové nebo kratší časové délky, jsou velmi významné ve vědě i ve stále větším počtu aplikací. Uvádíme základní vlastnosti světelných pulzů, způsob jejich generace lasery se synchronizací módů a připomínáme některé oblasti jejich použití., Ultra-short light pulses, with pulses of a picosecond or shorter duration, are very important in science as well as in a growing number of applications. We review the basic properties of these light pulses and techniques for their generation by modelocked lasers. We also describe some of their application areas., Petr Malý., and Obsahuje seznam literatury
The remarkable progress in laser technology leads also to a development of techniques of time-resolved optical spectroscopy. The ultrafast laser spectroscopy in the visible spectral region can be now used for investigation of rapid processes with the time resolution of about 10 fs. This paper reviews the experimental background and typical techniques of ultrafast laser spectroscopy. The potentional of ultrafast spectrocopy is illustrated with the results obtained by authors in the field of ultrafast relaxation processes in semiconductors and semiconductor nanostructures., Petr Malý, Petr Němec, František Trojánek., and Obsahuje bibliografii
Ultraslabá emise fotonů se vyskytuje prakticky u všech metabolicky aktivních biologických systémů. Jejím zdrojem jsou elektronově excitované stavy molekul vznikající v průběhu oxidativních reakcí biomolekul. Ultraslabá emise fotonů detekovatelná citlivými a nízkošumovými fotonásobiči a CCD kamerami může najít uplatnění v neinvazivních diagnostických metodách v zemědělství a biomedicíně., Ultra-weak photon emission is present in virtually all metabolically active biological systems. Its source is electronically excited states of molecules produced during the oxidation reactions of biomolecules. Ultra-weak photon emission detected with sensititive and low noise photomultipliers and CCD cameras can be exploited in non-invasive diagnostics in biomedicine and agriculture., Michal Cifra, Pavel Pospíšil., and Obsahuje seznam literatury
The article considers the writings of the sculptor Andreas Schweigl (1735-1812) and the painters Ignaz Chambrez (1758-1842) and Josef Heřman Agapit Gallaš (1756-1840). Around the year 1800, these three Moravian artists recorded their thoughts and insights in a number of texts that variously combined the traditional literary genre of artist’s biography with artistic topography, art criticism and a historical interpretation of early Moravian art and culture. Since all three were in some way connected with the new system of art education, the aim of this study is to examine whether and in what way standardized education affected not only their professional careers, but also their thinking. For all three, that thinking was rooted in a historical interpretation of the early art and culture of Moravia. All three discuss the function of art, artistic ideals, and to some extent the concept of the creative genius, as well as reflecting, directly or indirectly, on the theme of decadence as one stage in the cyclical view of history, in line with the paradigm of the age. The author sets out to compare their texts and in general terms show 1) how artists themselves viewed the importance of art education at the end of the 18 century; 2) how they responded to the changing role of the artist in society; and 3) how they defined artistic ideals and the artist’s social purpose. It is the wider implications of these changes in the artist’s social status, and in the function of art in Moravia and Central Europe generally, that form the primary focus of this study., Pavel Suchánek., and Obsahuje bibliografické odkazy