This paper highlighs the contribution of Philipp Lenard (Nobel Prize winner 1905) to the understanding of luminescence and reviews his main results in the field. In particular, the experimental spectroscopic technique introduced by Lenard and the properties of the so-called Lenard phosphors are discussed., Ivan Pelant, Jan Valenta., and Obsahuje seznam literatury
It is known that for a nonempty topological space X and a nonsingleton complete lattice Y endowed with the Scott topology, the partially ordered set [X, Y ] of all continuous functions from X into Y is a continuous lattice if and only if both Y and the open set lattice OX are continuous lattices. This result extends to certain classes of Z-distributive lattices, where Z is a subset system replacing the system D of all directed subsets (for which the D-distributive complete lattices are just the continuous ones). In particular, it is shown that if [X, Y ] is a complete lattice then it is supercontinuous (i.e. completely distributive) iff both Y and OX are supercontinuous. Moreover, the Scott topology on Y is the only one making that equivalence true for all spaces X with completely distributive topology. On the way to these results, we find necessary and sufficient conditions for [X, Y ] to be complete, and some new, purely topological characterizations of continuous lattices by continuity conditions on their (infinitary) lattice operations.
Krátké zamyšlení nad souvislostí struktury krystalů a jejich vlastnostmi a nad fyzikálními a geometrickými principy difrakce rentgenového záření., The article contains a brief contemplation on the relationship between the structure and properties of crystals and on physical and geometrical principles of X-ray diffraction., Václav Valvoda., and Obsahuje seznam literatury
Otázku, kde se berou zákony zachování hybnosti, momentu hybnosti, mechanické energie a dalších veličin, lze v rámci klasické mechaniky či teorie pole zodpovědět různými způsoby. Principiálně však zachovávající se veličiny souvisejí s operacemi symetrie daného problému. Tuto souvislost odhaluje pro případ teorií řídících se variačním principem teorém Emmy Noetherové z roku 1918, odvozený klasickým "souřadnicovým" způsobem užívajícím variací, tehdy ve variačním počtu obvyklým. Propracovaný moderní geometrický aparát fibrovaných variet a diferenciálních forem "kopírujících" jejich struktura je mnohem účinnějším prostředkem pro formulaci jak variačních teorií samotných, tak i jejich důsledků právě typu teorému Noetherové. Podstatu geometrického přístupu lze objasnit již na nejjednodušším případu - jednorozměrném pohybu klasické částice v mechanice., The question of the origin of conservation laws for the momentum, angular momentum, mechanical energy and other quantities in classical mechanics and classical field theories can be answered by various ways. Nevertheless, in principle the conserved quantities are connected with the symmetry of a problem under consideration. For variational theories such a connection was disclosed by the Emmy Noether theorem derived in 1918 by a classical "coordinate" procedure using variations, which was typical for the former calculus of variations. The elaborate modern geometrical formalism of fibred manifolds and differential forms adapted to their fibred structure is a much more effective tool not only for variational theories themselves but also for their consequences as the Noether theorem. The merit of the geometrical approach can be explained by the simplest example - a one-dimensional motion of a classical mechanical particle., Lenka Czudková, Jana Musilová, Jitka Strouhalová., and Obsahuje bibliografii