|
|
Study of the structural properties of model ceria based catalysts
Beran, Jan ; Mašek, Karel (advisor) ; Olejník, Kamil (referee) ; Lykhach, Yaroslava (referee)
This work is concerning the study of model ceria based calalysts structure by methods of electron diffraction RHEED and photoelectron spectroscopy XPS. The influence of deposition conditions and substrate on the growth of epitaxial cerium oxide films on copper single crystals is described in detail. The work then describes the interaction of cerium and tin in model systems and the creation of SnCeOx mixed oxide and its structure. In the last chapter, the interaction of palladium with cerium and tin oxide layers is examined, and the creation of paladium bimetallic alloys is described. Powered by TCPDF (www.tcpdf.org)
|
|
|
Study of gas sensing properties of tungsten oxide thin films
Vojík, Jiří ; Mašek, Karel (advisor) ; Ševčíková, Klára (referee)
Purpose of this thesis is a study of gas sensing properties of pure and platinum doped tungsten oxide thin films, which are deposited on a glass substrate. Needed films were prepared by magnetron sputtering method. Chemical composition and morphology of the films were investigated by means of XPS and SEM. It was discovered that prepared films are relatively flat and homogenous. They consist of polycrystalline WO3. It emerged that platinum which is present in modified films is in form of the PtO2 and PtO oxides. During subsequent heating of the films in air, which is needed for right function of films as sensors, PtO2 partially reduced. The resistance of the films decreased after heating. Sensing properties of the films were studied at 300 řC. The platinum doped film was more sensitive to exposition of hydrogen than the pure film.
|
|
|
Preparation and characterization of epitaxial tungsten oxide thin films
Pavlíková, Romana ; Mašek, Karel (advisor) ; Olejník, Kamil (referee)
Tungsten oxide thin films were prepared by vacuum evaporation on surfaces of Pd(111), Cu(111), Cu(110) and Cu(100) single crystals and studied by RHEED, XPS and AFM methods. The tungsten oxide deposition was done at temperatures from 300 řC to 400 řC in UHV or in oxygen atmosphere. The best deposition conditions - substrate temperature of 400 řC and oxygen atmosphere - were found resulting in growth of epitaxial and only partially reduced thin films. Thin films grown on the Pd(111) and Cu(111) surfaces consisted of two phases: a nearly atomically flat phase with (100) epitaxial plane and a phase formed by three dimensional particles with (111) epitaxial plane. Thin film deposited on Cu(100) also consisted of two phases: a flat film with (100) epitaxial plane and self-organised 1D structures parallel to Cu[010] and Cu[001] directions. Thin film prepared on the Cu(110) surface contained solely 1D structures parallel to Cu[1-10] surface direction. Capability of the partially reduced thin films for oxidation was studied. We applied oxidation using RF oxygen plasma, O2 exposure at elevated temperature and exposure to atmosphere. Thermal stability of the WO3/Cu(110) system was also investigated by heating up to 620 řC.
|
|
|
Digitizing of video and radio broadcasting in the Czech republic
Endris, Petr ; Slámová, Hana (advisor) ; Mašek, Karel (referee)
Cílem bakalářské práce je podat ucelený přehled procesu digitalizace televizního a rozhlasového vysílání v České republice. V úvodu jsou vysvětleny základní pojmy. V druhé kapitole je pojednáno o televizi jako novém médiu a o funkci médií ve společnosti. Třetí kapitola je věnována standardům a specifikacím digitálních zařízení. Jsou zde popsány televizní normy, rozdíl mezi HDTV a SDTV. Jsou také popsány možnosti příjmu vysílání v HD kvalitě a interaktivní služby. Čtvrtá kapitola je věnována institucionálnímu zabezpečení digitalizace - konkrétně Českému telekomunikačnímu úřadu, Radě pro rozhlasové a televizní vysílání a Národní koordinační skupině. V páté kapitole je vysvětlen samotný průběh digitalizace televizního a rozhlasového vysílání [Autorský abstrakt]. Powered by TCPDF (www.tcpdf.org)
|
|
|
Study of metal- tungsten oxide model system by methods of electron spectroscopy and diffraction
Polášek, Jan ; Mašek, Karel (advisor) ; Starý, Vladimír (referee)
In the present thesis structure, morphology, chemical and electronic properties of the Pt - Au/tungsten oxide model system were investigated by means of RHEED, AFM and PES. The epitaxial tungsten oxide thin films were prepared by oxidation of W(110) single-crystal surface using a RF oxygen plasma source followed by thermal annealing. Gold and Platinum were deposited "in-situ" by evaporation. Gold or platinum deposition led to the growth of oriented particles having (111) epitaxial plane as well as to the growth of polycrystalline phase. Platinum encapsulation was proved by CO adsorption observed by SRPES. Deposition of the second metal led to the formation of core - shell bimetallic clusters. Detail structure of the bimetallic system depends on the order of deposited metals and the substrate temperature. Thermal stability of the system was investigated by heating up to 600 řC.
|
|
|
Study of influence of the substrate temperature on the structure of epitaxial tungsten oxide layers
Pavlíková, Romana ; Mašek, Karel (advisor) ; Veltruská, Kateřina (referee)
Purpose of this thesis is a study of substrate temperature influence on structure, chemical composition and morphology of tungsten oxide thin films prepared by oxidation of a tungsten single crystal W(110) using a radio frequency plasma source. Thin film's parameters were observed by RHEED, XPS, AFM snad SEM. The substrate was oxidized at room temperature (RT) and at temperatures of 400ř C, 500ř C and 550ř C. In the first and the second case, produced thin films were amorphous and epitaxial structure was obtained by recrystallization. At the temperature of 500ř C, an epitaxial thin film was produced directly. After further heating at the temperature of 550ř C we got polycrystalline thin film without orientation of the crystal grains. All the epitaxial thin films had (111) crystallographic plane parallel to substrate surface. The tungsten oxide layers grew with relatively hight surface roughness in the order of several nanometers.
|
|
| |
|
| |
|
| |
|
|
Interoperability between component-based and service-oriented systems
Mašek, Karel ; Hnětynka, Petr (advisor) ; Parízek, Pavel (referee)
The component-based and service-oriented development have become commonly used techniques for building high quality, evolvable, large systems in a timely and affordable manner. In this setting, interoperability is one the essential issues, since it enables the composition of heterogeneous components and services. The aim of the thesis is to analyze possibilities of interoperability between the SOFA2 component system and the OSGi Service Platform, and based on that propose and implement a solution for mutual collaboration. The actual integration is based on the use of aspects and annotations. The issues connected with the runtime service management (e.g. binding/unbinding services) are handled by the control part of components using the aspects. While, the annotations serve for specifying service-enabled SOFA2 components in a declarative way. The OSGi support is incorporated in both the SOFA2 runtime environment and the tool for developing SOFA2 components. Furthermore, the outlined approach is general and can be easily reused for integrating other SOA-based systems as well.
|
guest ::
