Koncem června se z iniciativy francouzské ambasády uskutečnila návštěva tří nositelů Nobelovy ceny v Praze - byli to chemici Jean-Marie Lehn a Jean-Pierre Sauvage a fyzik Serge Haroche. Během tří dnů jsme měli možnost se s nimi potkávat nejen při "klasických " přednáškách, ale i na několika netradičních akcích. and Jan Valenta.
Vzestup české fyziky na přelomu 19. a 20. století je neodmyslitelně spjat s činností jedné velké osobnosti, zakladatele Fysikálního ústavu české university v Praze Čeňka Strouhala .Od jeho narození uplynulo 10. dubna 2010 právě 160 let., Jan Valenta., and Obsahuje bibliografii
At the beginning of the 20th century the task of reviewing all available literature across different scientific fields was initiated by professor Raýman, the general secretary of the Czech Academy of Emperor Franz Joseph for Science, Literature and Arts (CASLA). The first review for 1901 (in Czech language) appeared in the CASLA Bulletin during 1902. However, later, until the 1914 review, which was partially published in 1916, the reviews only consisted of physics reports. Usually, about five authors wrote the physical review covering different fields. Beginning in 1903, the review was also published as a separate book. The first 10 years of physical reviews referenced about 15 thousands papers from all available global literature., Jan Valenta., and Obsahuje bibliografii
Motto: "Pevnolátkové osvětlování je dnes tam, kde byl Internet v 80. letech. Stejně jako jsme tehdy nemohli předpovědět, jaký bude Internet, dnes, o 30 let později, nedokážeme předvídat, co všechno se stane se světelnou technikou a osvětlováním v příštích dekádách. Víme jen, že to bude úžasné a krásné." Roland Haitz, During its long evolution, techniques for artificial lighting used four main principles: combustion, incandescence, gas discharge and luminescence. The injection electroluminescence (taking place in light-emitting diodes, LED) is probably the most efficient way of converting electricity into light. In this paper we describe the main advantages and disadvantages of LED based light sources, as well as some topics of current research such as laser based light sources. Finally, the possible health effects of artificial lighting are briefly discussed., Jan Valenta, Ivan Pelant., and Obsahuje seznam literatury
The western part of the Bohemian Massif (Vogtland/West-Bohemia region at the Czech-German border) is characterized by relatively frequent intraplate earthquake swarms and by other manifestations of current geodynamic activity, such as mofettes, mineral and thermal springs. In this study we analyze variations of groundwater level in four hydrological wells in the region during the years 2005-2010. Monitoring during the previous time interval of 2000-2004 is also mentioned and used for comparison. Two of the wells are located in the epicentral region of Nový Kostel, and the other wells are more distant. The time interval includes the 2008 earthquake swarm when all the wells displayed a noticeable drop in the water level. This effect was observed up to epicentral distances of nearly 30 km, which exceeds the distances of hydrological changes observed during previous earthquake swarms. Moreover, it seems that a small rise in the water level preceded the intervals of increased seismic activity, which could represent a certain precursory phenomenon. On the other hand, the hydrological changes in the Nový Kostel area were relatively small, indicating that this epicentral area is not hydrologically linked with the seismically active fault at depth. Consequently, more suitable localities for hydrological monitoring should be sought in a broader vicinity of Nový Kostel., Renata Gaždová, Oldřich Novotný, Jiří Málek, Jan Valenta, Milan Brož and Petr Kolínský., and Obsahuje bibliografii