The first author, a high-school student, together with the second author, a project supervisor, presents a simple model of the solidification of liquid wax poured into a cylindrical vessel. The results obtained with the model are tested in a series of experiments carried out inside cylindrical containers of different dimensions. There is a good agreement achieved between theory and experiment. The main goal of this project is to identify and investigate a physical phenomenon which would test and enhance students‘ creativity., Karolína Rezková, Jana Musilová., and Obsahuje seznam literatury
O tom jak se rodily první přístupy k udržení horkého fúzního plazmatu pomocí silných elektrických a magnetických polí., Through his whole scientific career, carried out mainly at FTI Kharkov in the Soviet Union, O. A. Lavrentev (1926-2011) studied thermonuclear plasma confinement. Initially an electrostatic confinement and later a magnetic electrostatic plasma confinement was proposed by him. However, he did not describe the transition from the first to the second type of confinement, e. g., from the spherical concentric purely electrostatic trap to the magnetic trap formed by spindle cusp fields with its slits plugged by electrostatic fields, which represents the simplest type of an electromagnetic trap. This article offers a hypothesis of how O. A. Lavrentev transformed the earlier concept into the later one., Milan Řípa, Miroslav Šos., and Obsahuje bibliografii
Zatiaľ' čo jadrové skúšky spôsobili globálnu rádioaktívnu kontamináciu, Černobyľská havária (1986) mala dopad predovšetkým na európske krajiny a Fukušimská havária (2011) predovšetkým na Japonsko, aj keď uvoľnené rádionuklidy bolo možné sledovať v malých koncentráciách na všetkých kontinentoch ako aj vo svetových oceánoch a moriach. Havária Fukušimskej jadrovej elektrárne spôsobila v porovnaní s Černobyľskou haváriou (1986) približne 10-násobne nižší únik 131I a päťnásobne nižší únik 137Cs do životného prostredia. Radiačné dávky obyvateľstva nepresiahli v Japonsku 25 mSv/rok a v Európe boli rádovo 1 µSv/rok., Historical atmospheric tests of nuclear weapons have had a global impact on the radioactive contamination of the environment. Recent accidents at Chernobyl (1986) and Fukushima (2011) have had an impact on Europe and Japan, respectively, in addition small concentrations of radionuclides released from Fukushima have been registered on all continents as well as in oceans and seas. When compared with the Chernobyl accident, the Fukushima accident resulted in about a 10 fold increase in the release of 131I but a 3 fold decrease in the release of 137Cs to the environment. Following the Fukushima accident radiation doses did not exceed 25 mSv/year in Japan, whilst following the Chernobyl accident they were in the order of 1 µSv/year in Europe., Pavel P. Povinec., and Obsahuje bibliografii
Environmentální rastrovací elektronová mikroskopie představuje jeden z posledních vývojových trendů mikroskopických metod. Umožňuje zkoumání vzorků živé či neživé přírody v podmínkách vysokého tlaku plynů - až 3000 Pa oproti tlaku pod 0.001 Pa v klasickém rastrovacím elektronovém mikroskopu., Vilém Neděla, Rudolf Autrata., and Obsahuje seznam literatury