The aim of this study was to analyze the possibilities of various types of stent modeling and to develop some new models. A brief survey of basic properties of stents and a list of basic designs of stents is presented. Two approaches to stent modeling were identified. Structural mechanics is the theoretical background of our analytical model of a spiral stent. The finite element method was also used. The measurement equipment for model evaluation was developed., J. Záhora, A. Bezrouk, J. Hanuš., and Obsahuje bibliografii
Models of the variations and distribution of the upper atmosphere density are constructed, using modelled as well as observed data. Theoretical expression of the model is used in the equations of motion to study the drag effects of the atmosphere.
The known models of recent vertical movements of the Earth crust surface in the area of Poland were processed in the form of contour line map on the basis of the data of the first and second class geometric state levelling network. Second map done by Wyrzykowski (1985) was based on the results of measurements made in 1871-1882, 1926-1937, 1952-1956 and 1975-1977. The newest results of assignment of recent vertical movements of the Earth surface in the territory of Poland were published by Kowalczyk in 2006. The map of the contemporary vertical movements velocities has been processed using the least squares collocation method on the basis of repeated measurements of state precise levelling, executed mainly in 1974-1982 and 1997-2003. Presently, after about 3 years of satellite observations at about one hundred of permanent GPS stations of the ASG-EUPOS network, a verification of the mentioned models is possible on the basis of independent (satellite) measurements. As the resolution of the stations in Poland is sufficient, the model processed using satellite data was determined for the whole area of Poland and it was confronted with earlier (levelling) models. There are some differences in the analyzed models. A comparison of levelling and satellite mode ls indicates defect of reference distinctly resulting from sea level variability., Bernard Kontny and Janusz Bogusz., and Obsahuje bibliografické odkazy
Atomic nuclei are objects with a complicated internal structure but many aspects of their behavior can be understood in terms of relatively simple models. Since early times in nuclear physics many nuclear models have been developed. Among them, two basic types are of special importance. The shell model which converts the nuclear many-body problem to the independent movement of particles in a potential well, and the collective model which describes low energy excitations as the manifestation of the coherent motion of nucleons. In the article we review, in a nutshell, basic ideas which significantly influenced our understanding of nuclear phenomena., Atómové jadrá sú komplexné objekty so zaujímavými vlastnosťami a bohatou vnútornou štruktúrou, Dôležité informácie o dejoch vnútri jadier sa dozvedáme zo štúdia ich spektier a skúmaním jadrových reakcií. Pochopenie dejov vnútri jadier je nevyhnutnou podmienkou pre ich využitie v jadrovej energetike, medicínskych aplikáciách ale aj pre porozumenie procesom produkcie prvkov vo hviezdach., and František Knapp.
V sérii příspěvků [1-6] jsme čtenářům Českoslvoenského časopisu pro fyziku představili úlohy z minulých, zejména mezinárodních fyzikálních olympiád (MFO). V tomto příspěvku se naopak pokusíme předejmout, jaká úloha se objeví na letošní 44. MFO, která se bude konat v Dánsku., Martin Kapoun [et al.]., and Obsahuje seznam literatury
Příspěvek přináší základní matematické zakotvení pojmů „teorie chaosu". Představuje klíčové vlastnosti modelů chaotického chování dynamického systému s ohledem na explanační a prediktivní sílu modelů. Z pozice filosofie vědy podrobuje analýze především reprezentační aspekty modelů chaotické dynamiky systému. Nejzajímavějším aspektem těchto modelů je přísné omezení jejich reprezentační úlohy s ohledem na splnění podmínky hyperbolicity nutné pro platnost stínového lemma., This paper provides explication of basic mathematical concepts of "chaos theory". It indicates the key attributes of dynamic models of chaotic behavior of the system with regard to the explanatory and predictive power of these models. From the standpoint of philosophy of science it analyzes especially the representational role of chaotic models. The most interesting aspect of these models is a strict limitation of their representational role with regard to the fulfillment of the hyperbolicity condition necessary for the validity of the shadowing lemma., and Lukáš Hadwiger Zámečník.
Models of vernacular architecture are one of the best ways for the documentation of folk buildings. However, it is necessary to be aware of the fact that those models document the buildings visually, while their construction and material are documented only insufficiently. The research on the models showed that the models are made at more quality levels which differ in the fidelity of imitation of a constructional detail or material used. Even though the models will continue to be a suitable means to document vernacular architecture, it is necessary to replenish them with other documentation methods. The future of the models consists primarily in the presentation of folk buildings.
The text deals with models of vernacular architecture in collections of the Přelouč City Museum. The models were made by Antonín Pleskot (1909-1980), a native from Přelouč and a today less known author of vernacular architecture ́s models, in connection with the Přelouč Ethnographic Exhibition (1893) at the turn of the 20th century. The contribution also summaries his production. Pleskot produced historical and ethnographic models of different buildings for national heritage institutions and different museums throughout the then Czechoslovakia. His works were exhibited, among other places, in the National Museums in Prague and Bratislava, in the Moravian Museum in Brno, the Silesian Museum in Opava, the South-Bohemian Museum in České Budějovice and in Nitra.Pleskot was a member of the Marold Association of Fine Artists and took part in several exhibitions, including the Exhibition of Folk Art at the
Hybernians´ Palace in Prague in 1953.
The creation of cracks in non-conducting matter under mechanical stress is accompanied by electromagnetic field. Four ways of the crack behaviour are proposed implementing the dipole model. Supposing the use of capacitance sensors we derive the differential equation describing the transformation of primary crack parameters to the measured electrical signal and we solve it for these four conceptions of the crack development. The theoretical and experimental results were compared from which we can determine some primary crack parameters. and Tvorba trhlin v mechanicky zatěžovaných nevodivých látkách je doprovázena vznikem elektromagnetického pole. Na základě dipólového modelu trhliny byly navrženy čtyři základní průběhy jejího růstu. Pro případ použití kapacitního snímače byla odvozena a řešena pro každý ze čtyř případů diferenciální rovnice popisující transformaci primárních parametrů trhliny na měřený elektrický signál. Teoreticky odvozené průběhy byly porovnány s experimentálně získanými a odtud byly určeny některé primární parametry trhlin.