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Ab initio studie Lavesových fází v systémech Fe-Cr, Fe-Mo a Fe-Ta
Houserová, Jana ; Šob, Mojmír
Binary systems Fe-Cr, Fe-Mo and Fe-Ta can be found in many kinds of steels where the Laves-phase can be considered as a potential candidate for strengthening provided size and distribution of the particles are within certain limits. We performed electronic structure calculations to study the thermodynamic and structural properties of the C14 Laves phase with various compositions. In the frame of the thermodynamic study, we have evaluated the total energies of formation of Laves phase structure with different occupations of sublattices (Fe2Fe, Fe2X, X2Fe, X2X, where X stands for Cr, Mo and Ta) with respect to the Standard Element Reference (SER) states. These energies of formation are of great importance for prediction of stability of studied configurations.
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Ceramides and Dimethylamino Acid Derivatives as Skin Barrier Modulators
Novotný, Jakub ; Vávrová, Kateřina (advisor) ; Sedlák, Miloš (referee) ; Doležal, Pavel (referee)
The purpose of this work is to contribute to the understanding of the structure-activity relationships and behavior of the skin ceramides and transdermal penetration enhancers based on dimethylamino acid esters. First two chapters provide a theoretical background for understanding the main principles of transdermal drug delivery as well as composition and function of stratum corneum barrier. The experimental work is presented in the form of individual publications in chapters three to five. The first chapter describes transport routes through the human skin and gives an overview of enhancers of transdermal permeation with main accent on their chemical structure, mechanism of action, interaction with stratum corneum components and advantages and drawbacks of their use. The second chapter brings more detailed information on the specific content and composition of stratum corneum. The main attention is paid to the ceramides - a complex group of lipids that play a crucial role as cell signaling molecules and skin barrier constituents. In the skin, these sphingolipids form a major part of the stratum corneum intercellular lipid matrix, which is the barrier for penetration of most compounds. The development of such a protective layer was a critical step in the evolution of life on a dry land. Moreover,...
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Study of Properties of Metallic Thin Films and Nanostructures Using Scanning Probe Microscopy
Doupal, Antonín ; Fejfar, Antonín (referee) ; Kalousek, Radek (advisor)
This diploma thesis is focused on investigation of metallic thin films and nanostructures using scanning probe microscopy. Magnetic properties of these objects are studied by magnetic force microscopy, which is modification of scanning probe microscopy. In the theoretical part basic principles of scanning probe microscopy and magnetic force microscopy are summarized, and also principle of creation of magnetic domains and some special properties of ferromagnetic and antiferromagnetic materials. Further, two techniques of fabricating nanostructures are described. Experimental part is focused on imaging and simulating of magnetic domains. Further, exchange bias is revealed. This phenomenon is present in systems composed from ferromagnetic and antiferromagnetic materials. One part of this diploma thesis is also focused on discussion of problems with magnetic force microscopy.
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Theoretical description of imaging by a digital holographic microscope
Slabá, Michala ; Komrska, Jiří (referee) ; Chmelík, Radim (advisor)
The diploma thesis deals with theory of imaging in a transmitted-light digital holographic microscope using partially coherent illumination. The influence of spatial and temporal coherence state on optical sectioning property is solved. The coherent transfer function is calculated. From this function imaging characteristics for a two-dimensional scattering object are derived depending on its defocus. Two different designs of microscopes developed in the Laboratory of optical microscopy in IPE FME BUT are considered.
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Localized Surface Plasmons: Principles and Application
Kvapil, Michal ; Schmidt, Eduard (referee) ; Šikola, Tomáš (advisor)
The diploma thesis deals with plasmonic nanostructures for visible eventually near-infrared region of electromagnetic spectrum. At first, there are discussed basic terms which are necessary for description of plasmonic nanostructures and their properties. Then the resonant properties of gold nanoantennas on a fused silica substrate and in proximity of nanocrystalline diamond are addressed. FDTD simulations are used for an assesment of resonant properties and local electric field enhancement of these nanostructures. Possible manufacturing methods of the antennas and techniques for the measurement of their properties are mentioned at the end of the thesis.
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Optical properties of the GaN on sapphire
Skalský, Miroslav ; Janta, Jiří ; Čtyroký, Jiří ; Stejskal, J. ; Hüttel, I.
The method of mode spectroscopy was used to measure optical properties of epitaxial layers of gallium nitride (GaN) deposited onto the sapphire substrate. The results of the measurement of the layer thickness, refractive indices, and the attenuation of guided modes at the wavelengths of 632.8 nm and 781 nm are presented. From experimental values of attenuation of different guided modes, the contributions of bulk absorption and scattering at the interfaces of the layer to the total optical loss in the waveguide are determined.
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