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Start Over Format svazek Subject 6

1233. Supravodivosť má 100 rokov

Creator:
Samuely, Peter
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
supravodivost, dějiny, superconductivity, history, 6, and 53
Language:
Czech and English
Description:
One hundred years ago Heike Kamerlingh Onnes arrived to one of the most important breakthroughs of 20th century physics - he discovered superconductivity. His finding as in many other cases in the history of science had been a result of use of a very new experimental technique. He used the cryogenic equipment in his Leiden's laboratory with the liquid helium cryocooler and measured electrical properties of metals near the absolute zero temperature. When cooled down to extremely low temperatures, near 4 Kelvin, very pure mercury suddenly lost its electrical resistance completely. Many major physicists of 20th century, experimentalists as well as theorists, devoted their life efforts to exploration of the mysterious properties of superconductors. Superconductivity has been shown to be one of the rare cases where quantum physics is observed on a macroscopic scale. Many chemical elements and thousands of compounds have been found to be superconducting. Fifty years after the discovery important practical applications such as strong magnets for laboratories and magnetic-resonance-imaging in hospitals came to the market. But more than seventy five years the superconducting materials had been functioning only at extreme cold, below 23 K (-250°C). In 1986 the "hightemperature superconductor's" era started with materials superconducting at -100°C. This paper surveys the history and the latest research into one of today's most fascinating physics and promising technologies., Peter Samuely., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1234. Světélkování

Creator:
Valenta, Jan, Malý, Petr, and Hála, Jan
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
Pelant, Ivan, fyzika, physics, 6, and 53
Language:
Czech
Description:
K sedmdesátým narozeninám prof. Ivana Pelanta, jehož činnost se točí především kolem luminiscenční a nelineární optické spektroskopie., Jan Valenta, Petr Malý, Jan Hála., and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1235. Světélkující molekuly a mikroskopie za hranicí svých možností: Nobelova cena za chemii 2014

Creator:
Vácha, Martin
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
chemie, chemistry, 6, and 53
Language:
Czech
Description:
The Nobel Prize for Chemistry in 2014 was awarded for the development of super resolved fluorescence microscopic methods. This contribution introduces the two approaches, which overcome the diffraction limit of optical resolution, namely single molecule localization microscopy and spatially selective inhibition of fluorescence. The development of single molecule localization is followed from a historical perspective from its origins as low temperature single molecule spectroscopy to room temperature spectroscopy and imaging, which eventually led to methods of photoactivated fluorescence microscopy (PALM), stochastic reconstruction microscopy (STORM) and other high resolution techniques. The approach of spatial inhibition of fluorescence is demonstrated mainly by stimulated emission depletion (STED) techniques., Martin Vácha., and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1236. Světelné znečištění

Creator:
Moudrá, Milada
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fyzika, světelné znečištění, physics, light pollution, 6, and 53
Language:
Czech and English
Description:
Světelné znečistění odjakživa představuje palčivý problém zejména pro astronomy, kterým snižuje viditelnost noční oblohy. V posledních letech je však tomuto fenoménu věnováno mnohem více pozornosti i v jiných vědních oborech vzhledem k jeho negativním důsledkům, například v oblasti ochrany přírody, lidského zdraví, bezpečnosti či financí. V článku jsou tyto dopady stručně nastíněny a podrobněji jsou rozebrány fyzikální aspekty světelného znečištění, možnosti jeho měření a modelování a prognóza do budoucnosti., Light pollution (LP) poses a serious threat in particular, astronomers struggle with limited visibility of natural night sky objects. Due to the negative effects of bad lighting practices in various fields (e.g. environmental protection, human health, safety and security or economy) light pollution problematics have been extensively explored over the past years. This article presents a brief summary of these effects and a closer look into the physical aspects of light pollution, its measurement and quantification as well as future prospects., Milada Moudrá., and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1237. Světlo dávných časů

Creator:
Kulhánek, Petr
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fyzika, světlo, vesmír, physics, light, universe, 6, and 53
Language:
Czech and English
Description:
Všude kolem nás je přítomno reliktní záření, světlo z období konce velkého třesku, které v sobě nese cenné informace o raném vesmíru a o prostředí, kterým k nám procházelo. Při poznávání vesmíru získáváme většinu informací o vzdálených objektech prostředníctvím elektromagnetického záření nejrůznějších vlnových délek. V mikrovlném oboru sledují dnešní specializované sondy nejen nejchladnější zákoutí vesmíru, ale i světlo dávných časů, které se vydalo na svou pouť v období, kdy se ve vesmíru formovaly první atomy., Cosmic microwave background radiation exists all around us. It is the light from the end of the Big Bang, which carries valuable information about the early universe and the environment, throught which it has passed. Most of the Information about distant objects we obtain through electromagnetic radiation at various wavelengths. In the microwave band today‘s specialised probes watch not only the coldest corners of the universe, but also the light from ancient times, which started its journey during the period when electron shells in atoms formed in the universe., Petr Kulhánek., and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1238. Světlo v malířství

Creator:
Daniel, Ladislav
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fyzika, světlo v umění, malířství, physics, light in art, painting, 6, and 53
Language:
Czech and English
Description:
Let us look at light used in art from the perspective of art history. Light is important in the methods used for displaying reality and the formation of different styles in painting. During the middle ages painters sought not only to display the real behaviour of light in the world but used light to view transcendental elements. Magister Theodoricus for example seemingly placed the light source inside the volume of figures of saints, and thus strengthened their spiritual presence in the area of the chapel in Karlštejn castle. The master of the Wittingau altar used a shadow to amplify the mystery of the scene, like the Dutch masters from the early 15th century in their night scenes. By using sfumato, Leonardo forced the viewer to start actively looking at indistinct contours of his characters and thus intensified their vividness. Caravaggio from before 1600 put emphasis on the contrasts of light and darkness, thus his chiaroscuro figures sharply emenate into light. The light carves objects out of the surrounding darkness and facilitates composing images. During this time, Galileo through his telescope and his art of drawing identified "spots" of the Moon as craters. Simultaneously, Annibale Carracci, and before him Jan van Eyck and after him Velásquez and many others used mirror optics for various pictorial representations of reality. Together, relations between light phenomena, optics and painting are rich in their complexity. and Ladislav Daniel.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1239. Světlo v multimódových optických vláknech

Creator:
Tyc, Tomáš
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fyzika, optická vlákna, světlo, physics, optical fibres, light, 6, and 53
Language:
Czech and English
Description:
This article discusses light propagation in an optical fibre from the point of view of both geometrical and wave optics. We describe the fibre eigenmodes and their wavefronts, evolution of a general state of light along the fibre, and the modes of a bent fibre. Numerous figures are used to illustrate the presented priciples., Tomáš Tyc., and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1240. Světlo ve století světla

Creator:
Langer, Jiří
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fyzika, světlo, physics, light, 6, and 53
Language:
Czech and English
Description:
Zlaté sedmeré světlo, vůkol planoucí, duši ti dává směsice barev..., Light was the symbol of the Enlightenment or the Age of Light. The physics of light was widely studied and popularised at that time. The theoretical description of light inspired Maupertuis and Euler to formulate the Principle of the Least Action., Jiří Langer., and Obsahuje seznam literatury
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public