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Holocene Succession of Mollusc Assemblages in the Southern Part of Kokořínsko Area
Oravec, Jan ; Juřičková, Lucie (advisor) ; Beran, Luboš (referee)
The sandstone rock cities of the Bohemian Cretaceous Basin are traditionally considered floristically and faunistically impoverished areas, because the environment of acidic quartz sandstones complicates the development of developed biocenoses. The unfavourable abiotic conditions are compensated for geomorphological diversity of the landscape, which creates a wide range of locations providing habitats for many biological species with different ecological requirements. However, the current appearance of the sandstone areas is due to the extensive transformation of the environment in the late Holocene, as evidenced by the rich subfossil communities of terrestrial gastropods. In the presented study, the succession of postglacial malacocenoses was processed from five sites in the southern part of the Kokořínsko area, demonstrating the continuous development of species-rich forest habitats during the early and middle Holocene. The presence of calcareous encrustations on the surface of acidic sandstone walls, which allowed the continuous occurrence of calciphilous mollusc species, is also documented from this wet period. The gradual transformation of the natural environment is related to the beginning of the late Holocene and was caused by the leaching of nutrients from the soil horizons and the...
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Využití služeb Národní Identitní Autority v rámci přijímacích řízení vysokých škol
BERAN, Luboš
This master's thesis deals with the development of a system that will be able to use the services of the Narodni identitni autorita in the framework of the admission procedure at universities. It can be also used in other public institutions. The theoretical part explains terms related to Narodni identitni autorita and its functioning within the EU. The thesis also deals with whether universities are entitled to use the services of the Narodni identitni autorita. The architectural part presents the planned architecture and selected software. The implementation part deals with the installation and the configuration of software so that the thesis can be used as a guide for building a functional unit for the use of the services of the National Identity Authority.
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Construction of laser scanning magneto-optical microscope
Betušiak, Marián ; Němec, Petr (advisor) ; Beran, Lukáš (referee)
Title: Construction of laser scanning magneto-optical microscope Author: Marián Betušiak Department: Department of Chemical Physics and Optics Supervisor: prof. RNDr. Petr Němec, Ph.D., Department of Chemical Physics and Optics Abstract: The main goal of this thesis was to build a scanning magneto-optical microscope in the newly established Magneto-optical laboratory at the Department of Chemical Physics and Optics and particularly to compare different techniques for detection of magneto-optical (MO) signals. During the preparation stages, we first simulated the signal detected in different optical arrangements using Jones matrix formalism. Subsequently, we verified the functionality of the constructed microscope using a ferromagnetic sample of YIG:Pr and we compared experimentally different methods of the MO signal detection. Obtained experimental results are in perfect qualitative agreement with the predictions of Jones theory. Keywords: scanning magneto-optical microscope, Kerr effect, magnetic domains
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Study of physical properties of nanostructures using magneto-optical techniques
Beran, Lukáš ; Veis, Martin (advisor) ; Mistrík, Jan (referee)
Magneto-optical spectroscopy methods are used to study magnetic pro- perties of materials down to nanometer dimensions due to its high sensiti- vity and non-contact nature. This requires sophisticated experimental setup, advanced technical equipment and precise optical components arrangement. This thesis describes the basic physical principles of magneto-optical Kerr spectroscopy. On the basis of these principles is designed and developed a new, much simpler experimental setup with crossed polarizers. This arran- gement has the same order of sensitivity and accuracy of measurement as commonly used modulation techniques to which it is compared in this work. Finally, this arrangement is applied to the study magneto-optical properties of selected magnetic structures and these properties are discussed. 1
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Taxonomic revision of the genera Anisus in the Czech Republic (Mollusca: Planorbidae)
Zavoral, Tomáš ; Juřičková, Lucie (advisor) ; Beran, Luboš (referee)
The aim of this work is to critically review the anatomical and morphological characters being currently used in the determination of Central European species of the genus Anisus and to confront them with molecular characters. For the molecular analysis mitochondrial genes for 16S rRNA and cytochrome c oxidase - subunit I (COI) were used. DNA analysis showed that known species occuring in the Czech Republic form well distinguishable genetic lines. Subsequent revisions of the anatomical characters of these lines have proven that these characters are due to their variability not suitable for determination, especially for the differentiating of the species A. spirorbis and A. leucostoma. The conchological characters have proven more suitable, especially the ratio of the size of the last and penultimate whorl. With the help of this character, we can safely determine a population within which there are transitional forms in other morphological and anatomical characters.
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Optical and magneto-optical studies of ferrimagnetic garnets for photonic and spintronic applications
Beran, Lukáš ; Veis, Martin (advisor) ; Dubroka, Adam (referee) ; Výborný, Karel (referee)
Title: Optical and magneto-optical studies of ferrimagnetic garnets for photonic and spintronic applications Author: RNDr. Lukáš Beran Department: Intitute of Physics of Charles University Supervisor: RNDr. Martin Veis, PhD., Institute of Physics of Charles University Abstract: This doctoral thesis is devoted to fabrication and systematic char- acterization of physical properties of thin films of iron garnets with potential applications in photonic and spintronic devices. Investigated samples were pre- pared by metallo-organic decomposition and pulsed laser deposition. The study was focused on structural and magnetic characterizaiton along with optical and magneto-optical properties. Obtained experimental results were further con- fronted with theoretical calculations. The application potencial of garnets for photonic devices was discussed based on determined Figure of Merit (Faraday rotation to optical loss ratio). High values were achieved for single crystal thin film of Ce doped yttrium iron garnet on galium gadolinium garnet substrate as well as for pollycrystalline Bi doped yttrium iron garned on silicon substrate. Furthermore, new rare-earth garnets were prepared with attempt to achieve per- pendicular magnetic anisotropy of these film. This was achieved for three di erent materials, which were not...
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Study of physical properties of Heusler alloys
Beran, Lukáš ; Veis, Martin (advisor)
This diploma thesis is devoted to systematic study of structural trans- formations of Heusler alloys by means of spectroscopic ellipsometry and magneto-optical spectroscopy. Structural transformations in these alloys are induced by different microscopic mechanisms. Obtained experimental results were confronted with theoretical calculations. This allowed the discussion of obtained results and suggestion of their interpretation. In the case of Co- Fe-Si alloys, changes in optical and magneto-optical properties with change of Co-Fe ratio were observer. This was explained by lowering of the gap for minority spins with increasing Fe concentrations. Temperature dependent optical and magneto-optical properties of Ni-Mn-Ga alloy showed the pres- ence of so-called Martensitic transformation from cubic to tetragonal phase. A study of Mn-Rh-Co-Sn alloys did not show a clear dependence of physical properties upon the concentration of Rh and Mn. This was explained by strong strain inside the samples, which distorted obtained results. 1
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Optical and magneto-optical studies of ferrimagnetic garnets for photonic and spintronic applications
Beran, Lukáš ; Veis, Martin (advisor) ; Dubroka, Adam (referee) ; Výborný, Karel (referee)
Title: Optical and magneto-optical studies of ferrimagnetic garnets for photonic and spintronic applications Author: RNDr. Lukáš Beran Department: Intitute of Physics of Charles University Supervisor: RNDr. Martin Veis, PhD., Institute of Physics of Charles University Abstract: This doctoral thesis is devoted to fabrication and systematic char- acterization of physical properties of thin films of iron garnets with potential applications in photonic and spintronic devices. Investigated samples were pre- pared by metallo-organic decomposition and pulsed laser deposition. The study was focused on structural and magnetic characterizaiton along with optical and magneto-optical properties. Obtained experimental results were further con- fronted with theoretical calculations. The application potencial of garnets for photonic devices was discussed based on determined Figure of Merit (Faraday rotation to optical loss ratio). High values were achieved for single crystal thin film of Ce doped yttrium iron garnet on galium gadolinium garnet substrate as well as for pollycrystalline Bi doped yttrium iron garned on silicon substrate. Furthermore, new rare-earth garnets were prepared with attempt to achieve per- pendicular magnetic anisotropy of these film. This was achieved for three di erent materials, which were not...
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Construction of laser scanning magneto-optical microscope
Betušiak, Marián ; Němec, Petr (advisor) ; Beran, Lukáš (referee)
Title: Construction of laser scanning magneto-optical microscope Author: Marián Betušiak Department: Department of Chemical Physics and Optics Supervisor: prof. RNDr. Petr Němec, Ph.D., Department of Chemical Physics and Optics Abstract: The main goal of this thesis was to build a scanning magneto-optical microscope in the newly established Magneto-optical laboratory at the Department of Chemical Physics and Optics and particularly to compare different techniques for detection of magneto-optical (MO) signals. During the preparation stages, we first simulated the signal detected in different optical arrangements using Jones matrix formalism. Subsequently, we verified the functionality of the constructed microscope using a ferromagnetic sample of YIG:Pr and we compared experimentally different methods of the MO signal detection. Obtained experimental results are in perfect qualitative agreement with the predictions of Jones theory. Keywords: scanning magneto-optical microscope, Kerr effect, magnetic domains
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