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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.
41

Holografický modul pro světelnou mikroskopii / Holographic module for a light microscopy

Škrabalová, Denisa January 2019 (has links)
The new arrangement of the off-axis holographic module, which is using polarizationactive diffraction grating divides signal into reference and subject wave of an interferometer based on their polarization. However, current design of the module does not have a possibility to tune a length of the optical paths. Thus the inability to tune optical paths leads to a reduced quality of interference structure during observation of biological samples. The current module is only suitable for technical applicating due to this limitation. Possibility of tuning branches is key step in biological applications. Therefore a new computer-controlled module is created in order to enable use for biological samples.
42

Polarizační vidová disperze / Polarization mode dispersion

Turský, Aleš January 2008 (has links)
The work deals with dispersive effects of single mode fibers. We learn about the chromatic dispersion, the main attention is paid to the Polarization Mode Dispersion. We clarify the root cause origin of the Polarization Mode Dispersion describing parameters and its effect on transmitted data. Further on, the works dedicates to measure methods of the Polarization Mode Dispersion which is the interferometric method or the POTDR method. We explain the ways of the PMD removal at contemporary optic routes and options of PMD compensation by using compensators of various types. There is also mentioned the possibility of profiting from the soliton transmission. The last chapter deals with measuring of a real optic route. It includes measured data and its evaluation due to the ITU-T demands.
43

Dvoupásmová anténa pro Globální navigační satelitní systém / Dualband Antenna for Global Navigation Satellite System

Mikulášek, Tomáš January 2009 (has links)
This master’s thesis introduces to the reader with a modern antenna type the microstrip patch antennas. The most common types of microstrip antennas and their parameters and feeding methods are introduced in the theoretical section of this master’s thesis. This section deals with the circularly polarized microstrip antennas. Design of an active dual-band circularly polarized antenna for global navigation satellite application in the AWR Microwave Office is presented in the practical section. The proposed single-fed dual-band circularly polarized design is achieved using two stacked square microstrip patches. The antenna operates at the L1 + E1 and L5 + E5a frequency bands. Antenna preamplifier consists of a low-noise transistor and a dual-band band-pass filter. The thesis describes realization and measurement results of the dual-band antenna performance in the anechoic chamber. Measured results of the preamplifier performance are presented.
44

Použití nanoplniv v elektroizolačních materiálech / Application of nanofiller in electroinsulating materials

Mohyla, Petr January 2010 (has links)
This project deals with calculation parts of complex permittivity varnish samples which is filled by nanoparticles of metal oxides. Opening of this project deals with theory of dielectric and effects in dielectric, theory of compounds and expressions in composite systems. Following topic is theory of nanoparticles and nanotechnologies and summarize adjusted results about this branch of knowledge. In practical part of work is include method which was use to make varnish samples filled by nanoparticles, prepare to measurement methods and whole results of measurement. In the end of work is analysis influence of filler particles each filler types to dielectric material and results verified mixture mathematical expressions.
45

Ozařovač parabolické antény v pásmu X / Parabolic antenna feed for X band

Lecián, Petr January 2010 (has links)
The work addresses the unusual proposal feed for parabolic antenna with circular polariza-tion signal. This is a modified waveguide feed, waveguide polarizer with a septum. Contemporary RHCP and LHCP wave occurs in several applications of microwave commu-nication and measurement system. From this point of view the septum polarizer can be useful. The septum polarizer is a four-port waveguide device. The square waveguide at one end con-stitutes two ports because it can support two orthogonal modes. A stepped septum divides the square waveguide into two standard rectangular waveguides sharing a common broad-wall. The size of the septum as well as two versions of the waveguides excitation were analyzed and are described in this paper. Ansoft HFSS is software for design and simulation of feed. This software can visualize not only the specified model feed, but also the course of electromagnetic field in feed and over time.
46

Měření permitivity a ztrátového činitele vody / Measurement of permitivity and dissipation factor of water

Zimáková, Jana January 2012 (has links)
This master `s thesis deals about the dielectric properties of water. It describes the basic chemical and physical properties of water and its distribution in terms of structure. It also describes the basic parameters of distilled water, deionized and superclean. In the chapter number 5 described the behavior of dielectrics in an electric field, determining the dipole moment by Claus-Mossotti 'equation, measurement of permittivity and loss factor. Practical part is consists of the design of the electrode systém, of measuring the water quality and evaluation of measured data
47

Binokulární vidění / Binocular vision

Brichta, Tomáš January 2012 (has links)
In this work I have been briefed by physiology of binocular vision for acquisition of three-dimensional perception from two-dimensional images using special glasses. At first I described optical organ, after it I described physiology of binocular vision. In the next part of my work I described stereoscopic imaging technology and their advantages and disadvantages. In the next part of this work I have designed method for measuring ideal distance between cameras for scanning and projection of stereoscopic image using program Inition StereoBrain Calculator. After scenes design I have collected visual data for creating 3D videos. This videos were been projected to the group of the viewers. Data from the viewers were been analyzed afterwards.
48

Chování feroelektrik v teplotní oblasti / The behaviour of ferroelectrics in the temperature range

Czanadi, Jindřich January 2012 (has links)
The submitted thesis describes characteristics and use of the ferroelectric material which has their utilization in electronics and electro technical industry. The thesis describes behaviour ferroelectrics in temperature range. A suitable workplace was designed and its functionality was verified in selected ferroelectrics samples dependence of temperature of components of complex permittivity.
49

Vlastnosti perspektivních feroelektrických materiálů / Properties of the perspective ferroelectric materials

Krejčí, Josef January 2012 (has links)
This thesis studies the properties and the applications of prospective ferroelectric materials which are used in electrical engineering and electronic industry. Further are physically explained and mathematically described the basic principles running in their structure. The practical part is aimed to build a workplace for measuring the components of the complex permittivity in the frequency and temperature area, controlled by the programmed measurement and service application using the Agilent VEE Pro 8.0 and MS Excel. The functionality of the workplace was verified on the selected material samples by measurement and evaluation of selected properties. For this issue was created electronic text, which can be used as a guide for laboratory exercises and it is an integral part of this work.
50

Nanometrologická vibrometrie / Nanometric vibrometry

Ševčík, Michal January 2013 (has links)
This thesis deals with the precise measurement of distances in nanometer range at ultrasonic frequencies for the purposes of vibrometry. The paper is primary focused on~nanometric displacement measurement methods. First the thesis deals with the physical phenomena based on light in the theoretical section. This includes interference of light, index of refraction, polarization, interferometry and more. Understanding of these physical laws is crucial for design and assembling of the interferometer. Subjects of interferometric method for precise and fast measurement of the nanometric displacement and vibration are discussed. Interferometer components such as lasers, photodetectors and optical elements are described are described in the final part of this section. Practical section of thesis can be divided into two parts. The design and assembling issues are discussed in the first section. Many problems which I had to solve are described. Control software and implementation of the signal processing is the subject of the second part. I met with particular problems such as phase unwrapping. I solved this problem of discontinuous phase field with user written algorithm. Finally the graphical user interface was created. Using assembled interferometer and written software application I measured vibration of Langevin transducer on ultrasonic frequencies.

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