National Repository of Grey Literature 269 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Phase imaging below the diffraction limit
Nečesal, Daniel ; Bouchal, Zdeněk (referee) ; Dvořák, Petr (advisor)
Tato diplomová práce se zabývá konstrukcí interferenčních zařízení pro výzkum měření fáze světla na mikro-strukturách a fáze plazmonů na nano-strukturách. V první kapitole je vybudován teoretický základ pro optiku a nano-fotoniku používané v budoucích kapitolách. Následně je popsána interference vln a jejich praktické použití pro prolomení difrakčního limitu pomocí holografie plazmonů. Prvním experimentální sestavou je Machův-Zehnderův holografický mikroskop. Je popsán způsob, jak ho sestavit z běžně dostupných součástek a jak je navržen ovládací software k jeho používání. Následně jsou popsány výsledky naměřené pomocí tohoto zařízení. V poslední kapitole se zaměříme na sestavení holografického SNOM přístroje pro studování plazmonů a jejich interference. Nejdříve popíšeme základní princip a navržení softwaru pro automatizaci měření, pro zrychlení vědeckých postupů. Nakonec předložíme výsledky měření mikroskopu.
Interaction between SNOM tip and near-field
Krpenský, Jan ; Kvapil, Michal (referee) ; Dvořák, Petr (advisor)
Interaction between a probe for scanning near-field optical microscopy (SNOM) and near electromagnetic field is a fundamental problem, with its solution being a necessary condition for the correct interpretation of experimental data. This bachelor's thesis is aiming to thoroughly describe this problem and by precise manufacturing of our own SNOM probes help to reach solution of this problem. For this purpose, the detection of near-field generated by interference of surface plasmon polaritons (SPP) on square shape nanostructures is being used. This study has proven the dependence of SNOM probe sensitivity to near-field components on the size of a SNOM aperture.
Extension of the production hall
Dvořák, Petr ; Rubina, Aleš (referee) ; Rubinová, Olga (advisor)
The bachelor thesis deals with the design of air-handling devices for the first floor of the production hall extension. The devices are designed to achieve operational, functional, and hygienic requirements. The changing room and sanitary facilities are warm air heated. For purposes of the showrooms is designed central air conditioning. The dining room and food preparation areas are also air-conditioned. The theoretical part focuses on the influence of the shading coefficient and direct solar radiation on the course of heat gains.
Push-pull quasi-resonant DC/DC converter with a transformer
Dvořák, Petr ; Vorel, Pavel (referee) ; Martiš, Jan (advisor)
This diploma thesis deals with analysis of function and subsequent construction of a quasi-resonant DC / DC converter 300 V / 50 V for an output of about 1.5 kW. The aim of this work is to test and describe the behavior of an experimental converter at various operating parameters. In the theoretical part, resonant circuits are described, as well as our connection of the resonant converter. Based on the used topology and the simulated behavior of the converter, the individual components of the power circuit and its control and excitation circuit are designed in Chapters 4 and 5. The sixth chapter deals with the construction and testing of the converter, including a description of its behavior. The last chapter contains technical documentation.
Dvořák, Petr ; Rezek, Bohuslav (referee) ; PhD, Jakub Dostálek, (referee) ; Šikola, Tomáš (advisor)
This thesis deals with an experimental research of the surface plasmon polaritons (SPPs) using Scanning Near-field Optical Microscopy (SNOM). The first chapter provides theoretical background and a description of most of the physical phenomena and relevant dependencies studied in this work. These dependencies include the dependence of the resulting SPP image on homogeneity, polarization, wavelength and phase of the illumination, on the geometry of the interference structures and on the tilt of the sample with respect to the illumination. Further, this work presents a new experimental method which, using the numerical simulations or SNOM measurements, allows to estimate the sensitivity of SNOM probe to detect the individual electric intensity components of the near-field. At the end of the thesis, the work presents a new microscopic technique which enables a 3D quantitative imaging of phase distribution above the plasmonic metasurfaces.
Diversity of microalgae from extreme habitats: linking phylogeny and ecology
Barcyte, Dovile ; Nedbalová, Linda (advisor) ; Dvořák, Petr (referee) ; Bock, Christina (referee)
The diversity of microalgae from extreme habitats is far from being fully explored and understood. This is due, in part, to limited sampling efforts along with complex algal taxonomy and systematics. In particular, little investigated extremely acidic (pH < 3.0) and polar habitats might veil novel, undescribed species. This doctoral thesis aimed to study algal strains isolated from acidic or acidic and hot, and cold environments using a polyphasic approach. It focused on coccoid (Coccomyxa and Watanabea), monadoid (Chloromonas and its relatives) and saccoderm (Cylindrocystis) green microalgae from the classes Trebouxiophyceae, Chlorophyceae, and Zygnematophyceae, respectively. In addition, coccoid red algae (Galdieria) from the class Cyanidiophyceae were covered. The main research methods included light and transmission electron microscopy combined with Sanger sequencing. Nuclear 18S rDNA and plastid rbcL sequences were used for construction of phylogenetic trees for taxonomic position evaluation. Comparisons of secondary structure models of the highly variable ITS2 rDNA molecular marker served for a more detailed genetic relationship estimation among close relatives. Results have shown that Coccomyxa and Watanabea are present in extremely acidic lakes and that acidity and increased availability of...
Design of 3D-printed Unmanned Aerial Vehicle
Sladký, Martin ; Jetela, Václav (referee) ; Dvořák, Petr (advisor)
This bachelor thesis deals with the design proposal of the unmanned aircraft produced by FDM technology. The introduction is devoted to a brief overview of 3D printing technologies and the research of design strategies used for the production of 3D printed aircrafts. The second part is devoted to the design itself. Two types of winglets, wing and central part of the aircraft were designed. The individual parts of the aircraft have been converted to G-code format and printed on a 3D printer. Finally, the aircraft was assembled.
Experimental evaluation of appropriate FDM technology for UAV production
Hubáček, Jan ; Klement, Josef (referee) ; Dvořák, Petr (advisor)
This bachelor thesis deals with material analysis and design of technology for Fused Deposition modelling 3D printing method of unmanned aerial vehicles. Nine materials which are suitable for this application has been tested. Tension test has been used to determine mechanical properties of each material according ISO standards for plastics. Material had to met certain criteria, which are important for 3D print of aeroplanes, to pass to the next stage of experiment. Next three-point flexural test of wing has been used. In this test has been tested two glued sections of wing root and one separate section of wing. Results of tensile test and flexural test were compared and evaluated. It was discovered that material PLA, which is commonly used for printing aeroplanes, has not been overcome. Materials that seems to have better mechanical properties has been disadvantaged for its bad properties in 3D printing process.
Use GPS for in flight measurement
Čížková, Markéta ; Dvořák, Petr (referee) ; Jebáček, Ivo (advisor)
Bachelor thesis Use GPS for In-Flight Measurement addresses the applicability of Global Positioning System as a tool for aircraft certification. The theoretical part of thesis aims to acquire the GPS principle, it deals with accuracy of the system and methods of certification. The practical part contains a comparison of altitude measurement using GPS and Pitot-static system in a gliding flight.
Design of folding propeller for UAVs
Dítě, Radovan ; Dvořák, Petr (referee) ; Popela, Robert (advisor)
This master's thesis deals with the design of foldable propeller for UAVs. The design of the foldalble propeller is created based on theory of propellers and also on tha detail ana-lyzis of existing foldalble propellers with similar dimensions. The propeller is then manufac-tured and tested. One of the part of this thesis also describes design of central hub. At the end the methodical procedure of creating foldable propellers is suggested.

National Repository of Grey Literature : 269 records found   1 - 10nextend  jump to record:
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