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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Polarizační verze lesklých BRDF modelů / Polarising Versions of Glossy BRDF Models

Bártová, Kristina January 2014 (has links)
The goal of computer graphics is to precisely model the appearance of real objects. It includes of interactions of light with various materials. Polarisation is one of the fundamental properties of light. Incorporating polarisation parameter into an illumination model can significantly enhance the physical realism of rendered images in the case of scenes including multiple light bounces via specular surfaces, etc. However, recent rendering systems do not take polarisation into account because of complexity of such a solution. The key component for obtaining physically correct images are realistic, polarisation capable BRDF (Bidirectional Reflectance Distribution Function) models. Within this thesis, polarising versions of the following BRDF models were theoretically derived: Torrance Sparrow, He-Torrance-Sillion-Greenberg and Weidlich-Wilkie. For each of these models, Mueller matrices (the mathematical construct used to describe polarising surface reflectance) were systematically derived and their behaviour tested under various input parameters using Wolfram Mathematica. Derived polarising glossy BRDF models were further implemented using a rendering research system, ART (Advanced Rendering Toolkit). As far as we know, it is the very first usage of these BRDF models in a polarisation renderer....
22

Socioekonomická polarizace v Česku / The social-economic polarization in Czech Republic

Kozáková, Lucie January 2015 (has links)
This thesis main topic is the social-economic polarization in Czech Republic and its development process within past two decades. The main aim is to define growth poles with positive social-economic development and peripheric areas with stagnating or negative development. Consequently the secondary aim of this thesis is to confirm or disprove hypothesis resulting from Myrdal's theory of cumulative causation: "Growth poles grow faster over time and conversly peripheric areas decline further over years." In next step growing and peripheric regions are described and the possible causes of develepment within this areas are interpreted. Leading theories of regional development focusing on social-economic growth polarization are described in the theoretical part. The emphasis is on core -- periphery theories with main focus on theory of cummulative causation by Gunnar Myrdal.
23

Vliv dvojlomu jednovidových optických vláken na činnost polarizačního multiplexu / Influence of single mode optical fiber birefrigence for polarization multiplex

Šimák, Petr January 2018 (has links)
Thesis deals with polarization multiplexing and how birefringence influences polarization multiplexing. It also deals with polarization of light and how it can be described by Stokes and Jones vectors and also with visualiating polarization on Poincaré sphere. It also describes how information is transmitted in optical systems. At the end of the thesis is described design for polarization multiplexing at the lab.
24

Využití polarizace světla při filtraci optického signálu / Utilization of light polarization when filtering the optical signal

Alexa, Jan January 2018 (has links)
This master thesis deals with the possibility of separation of useful signal from noise using polarization of laser radiation. This thesis is structured into 5 thematic units. The first unit is focused on laser radiation and its properties. The second part contains a deeper focus on the polarization of radiation, its description and the possibilities of measuring the polarization states. The third part of the thesis is devoted to the design of the measuring chains and identification of used elements. Chapter four contains measurement of status of the polarization and its results. The last chapter analyzes particular measuring chains outputs according to their spectral characteristics.
25

Návrh optovláknového tepelného senzoru pro detekce narušení obranného perimetru / Design of optical fiber temperature sensor for detection of defense perimeter

Zámečník, Ondřej January 2021 (has links)
This diploma thesis deals with the issue of measuring the ambient temperature using a~single-mode optical fiber used as a temperature sensor. The thesis describes the basic knowledge about polarized light, its propagation in optical fiber and describes special fibers that preserve polarization. It also deals with the representation of polarization states on a Poincaré sphere and the use of Stokes and Jones vectors. In the practical part, several selected methods of optical signal supply to the temperature sensor are measured. Subsequently, the suitability of the given methods is evaluated from the measured results and the courses are compared with the records measured from real routes. This thesis aims to select a suitable connection of a temperature sensor for a long route of optical fiber and verify its functionality.
26

Strukturální a elektrické vlastnosti PVDF-CNT kompozitu / Structural and electrical properties of PVDF-CNT composite

Misiurev, Denis January 2021 (has links)
Electrospininig se osvědčil jako jeden z nejpopulárnějších a nejrozšířenějších způsobů výroby vysoce kvalitních vláken s požadovanými parametry. Kvalita a morfologie vyráběných vláken závisí na mnoha parametrů, jako je vlhkost, dávka materiálu, aplikované napětí atd. Omezení keramických piezomateriálů (křehkost, toxicita vzorků obsahujících olovo, obtížnost přípravy složitých tvarů atd.) vynutila výzkum v oblasti piezoelektrických polymerů. Jedním z nich je polyvinylidenfluorid (PVDF). polyvinylidenfluorid může by být připraven v různých formách: tenké filmy, objemové vzorky, vlákna. PVDF vlákna přitahují největší pozornost díky vysoké flexibilitě, nízké hmotnosti, mechanické stabilitě a chemické inertnosti. Vlastnosti PVDF vláken lze zlepšit pomocí doplňujících materiálů: keramické částice, kovové nanočástice, Graphicitové materiály jako jsou oxid Graphicenu nebo uhlíkové nanotrubičky (CNT).
27

3D tisk optomechanických zařízení / 3D printed opto-mechanical devices

Šremrová, Vendula January 2021 (has links)
Optomechanical components are widely used in many optical experiments. This diploma thesis deals with design and manufacturing optomechanical components using 3D print technology. These are cheaper alternatives of commercial devices. In addition to 3D printed parts, minimum number of other components are used to assemble functional devices. Using simple experimental setups, the manufactured components are evaluated and compared with commercially available ones. The results show that they can be used in applications where high accuracy is not required. The second part is devoted to the design and manufacturing of a polarimeter as a mechanism combining electrical and mechanical components with 3D printed parts. The polarimeter is used to measure some properties of polarized light.
28

Mikropásková anténa s kruhovou polarizací s možnosti výběru typu polarizace / Dual-port microstrip circularly-polarised antenna

Holek, Karel January 2008 (has links)
The thesis is focused at the design and the execution of a dual-port microstrip circularly-polarized antenna for the frequency of 2.4 GHz. The first part describes general knowledge about microstrip antennas, circularly-polarized, options of power supply, used medium etc. The second part of the thesis deals with the design and simulation of antennas with the use of software called CST Microwave Studio and Zeland IE3D. In the last part, confrontation of simulation and measurement results is provided.
29

Návrh anténního systému s kruhovou polarizací pro kmitočtové pásmo 2,4 GHz / Designing circularly polarized antenna for frequency band 2,4 GHz

Jiříček, Zbyněk January 2008 (has links)
Diploma thesis is focused to design of a system with circularly polarized wave for frequency band 2.4 GHz. The thesis introduces question of the microwave antennas, matching circuits and circular polarization circuit. It also includes a design of a circuit for available chip antenna (2450AT45A100) measurement and its measuring with connected chip antenna. Design and measurement of a circular polarization circuit using available chip antennas are also included in this thesis.
30

Optoelektronický senzor stavu polarizace světla na biologických vzorcích / Optoelectronic sensor of polarization state of light from biological samples

Mikláš, Jan January 2010 (has links)
The living body tissues consist of cells which dimensions are bigger than a wavelength of visible light. Therefore a Mie scattering of reflected of backscaterred light occurs and different polarization states arise. The changes of polarization state due to the multiple scattering of light in the biological cellular tissues allow measure the aging of biological tissue. The reflected or backscattered polarized laser light exhibits multiple scattering on the sample surface and in its subsurface area.

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