|
|
Positron annihilation study of precipitation effects in Mg-Tb alloy
Hruška, Petr ; Čížek, Jakub (advisor) ; Vlach, Martin (referee)
Magnesium alloys are currently widely used in industry as a modern material. Magnesium based alloys with rare earth elements shows very promising mechanical properties. In the present work the precipitation effects and the deve- lopment of microstructure of the Mg13Tb alloy (containing 13 wt.% of terbium) during isochronal annealing were studied by positron annihilation spectroscopy, microhardness measurement and differential scanning calorimetry. According to the results the creation of the precipitates β′′ , β′ and β in the studied alloy was observed and activation energies of these precipitates were determined by the Kissinger method. By microhardness measurement the natural ageing at room temperature of the Mg13Tb alloy was observed and described. 1
|
|
|
Copyright aspects of radio broadcast
Čížek, Jakub ; Žikovská, Petra (advisor) ; Wünschová Pujmanová, Alexandra (referee)
1 RESUMÉ This dissertation focuses on selected aspects of copyright and rights related to copyright in connection with radio broadcasting. It specializes in use of authors' works, artistic performances of performers and phonograms of phonogram producers in the way of radio broadcasting and on internet connected to radio broadcasting according to the current legislation in Czech Republic. In the first part it concentrates on items of copyright protection, their use in radio broadcasting, on broadcasters as users in the view of copyright law, on licence agreement, term of protection and radio broadcasting itself. As far as the broadcasting is concerned the dissertation approaches it in the view of administrative law focusing on its content. In the second part it deals exclusively with collective rights management as with the key institute for broadcasters to get appropriate copyright licences to use the protected items. It concerns the compulsory and voluntary collective rights management, the cumulative agreements and royalties, and collecting societies operating in Czech Republic. With regard to the present trends this dissertation, in its third part, aims at broadcasters' activities on internet and further platforms. The last part is devoted to several nowadays issues in copyright, such as extension of...
|
|
|
Studium mikrostruktury ultrajemnozrnných kovových materiálů metodou pozitronové anihilace
Barnovská, Zuzana ; Čížek, Jakub (advisor) ; Procházka, Ivan (referee)
In the presented thesis we study the changes in distribution of the size of vacancy clusters in metals processed by severe plastic deformation, so called ul- tra fine grained materials. We use a modern non-destructive method of positron annihilation spectroscopy, which is one of the few methods that allow us to inves- tigate point defects like vacancies with sizes of a few ˚A. The obtained spectra of positrons annihilating in the samples enable us to determine changes of vacancy cluster sizes depending on temperature or severity of the deformation applied on the samples. 1
|
|
|
Studium defektů ve slitinách na bázi Fe3Al metodou pozitronové anihilační spektroskopie
Lukáč, František ; Čížek, Jakub (advisor) ; Jirásková, Yvona (referee)
The correlation of vacancy concentration with microhardness of Fe-Al alloys was studied on samples quenched from 1000 řC and subsequently annealed at lower temperatures. Using X-ray diffraction the lattice parameter and crystal structure were determined for samples of Fe-Al alloys. By measurements of positron lifetime was revealed the high concentration of vacancies in quenched samples and subsequent annealing caused significant decrease in vacancy concentration while in samples with Al content above 39% also the decrease of microhardness was measured. Measurements of coincidence Doppler broadening of annihilation peak helped to distinguish the annihilations coming from positron trapped or delocalized annihilated by electrons of both atoms, Fe and Al. Comparison of measured results with theoretical quantum-mechanics calculations performed in this diploma thesis determined the most probable defect type as a vacancy on A-sublatice of B2 structure.
|
|
|
Studium defektů v kvazikrystalech metodou pozitronové anihilační spektroskopie
Vlček, Marián ; Čížek, Jakub (advisor) ; Smola, Bohumil (referee)
In the present work positron lifetime spectroscopy and coincidence spectroscopy of Doppler broadening of annihilation radiation were employed for investigations of defects in Mg alloys with icosahedral phase. Samples of WE43 alloy and WE43 alloy modified by addition of zinc were investigated. Positron trapping at vacancy-like defects associated with interface between the icosahedral phase Mg3Zn6Y1 and Mg matrix was observed. Investigations of MgZnAl-based alloys were performed as well. Vacancy-like defects were not detected in MgZnAl- based alloys by positron lifetime spectroscopy. However, coincidence spectroscopy of Doppler broadening of annihilation radiation revealed that positron trapping in the vincinity of icosahedral Mg44Zn41Al15 phase occurs. Several hypotheses ex- plaining different nature of positron trapping in WE43-based and MgZnAl-based alloys were proposed. Keywords: quasicrystals; positron annihilation spectroscopy; positron trapping; open-volume defects
|
|
| |
|
| |
|
| |
|
|
Implementation methodology for pre-customized IS SAP
Čížek, Jakub ; Říhová, Zora (advisor) ; Ošmera, Jiří (referee)
This thesis deals with project management and methodologies for information systems implementation, particularly for IS of SAP AG. The first part of the work describes basic problems of project management and introduces certain project management methodologies. ASAP and ASAP Focus methodologies are described in more detail. The second part of this work uses these fundamentals to analyze frequent problems on projects of real company that implements pre-customized IS of SAP AG. Solutions for these problems are proposed and a brief methodology is created as a result of the work.
|
|
|
Digitální fotografie a algoritmy pro rozeznávání obrazové informace
Čížek, Jakub ; Horný, Stanislav (advisor) ; Bébr, Richard (referee)
Tato práce se zabývá vznikem digitální fotografie. Kromě základního popisu a rozdělení digitálních fotoaparátů a jejich charakteristických součástí, je zde kladen důraz na vysvětlení vzniku barevného obrazu v digitálním přístroji. Podrobněji se tato práce zabývá především algoritmy pro rekonstrukci barevné informace ze surových dat (RAW) snímače. V poslední části je též provedeno srovnání různých interpolací barevného obrazu v praxi a diskuze vhodnosti jednotlivých postupů.
|
guest ::
RSS feed.