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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.
31

Vliv plnění na dielektrické vlastnosti elektroizolačních laků / Influence of Filling on Dielctric Properties of Electroinsulation Varnish

Kisiala, Ondřej January 2008 (has links)
This work deals with issues of elecroinsulating varnish and composite materials. The general aim is to observe impact of fulfilment and size of particle against measured values.
32

Dielektrické vlastnosti termoplastů plněných mletou slídou / Dielectric Properties of Thermoplastic Materials with Ground Mica

Fiala, Ivo January 2008 (has links)
The subject of this thesis are composite materials, measuring of their dielectric qualities, particularly of the polyamide and the polyamide filled with various weight percentage of the ground mica. The essential intent of the thesis is to determine the measuring methodology and respective measurement of the basic dielectrical quantities of materials, as are loss factor and the complex permitivity components. The measuring should be done for various temperature and humidity combinations. The thesic contains the physical explanation of measured dependences.
33

Vliv plnění nanočásticemi na dielektrické vlastnosti elektroizolačních laků / Influence of nanoparticles on the properties of electroinsulation varnish

Michlíček, Petr January 2009 (has links)
This work deals with issues of dielectric composite materials. The general aim is to observe how the amout of nanofilling influence dielectric spectrum in dependence on relative humidity and temperature which is measured on prepared samples. For this purpose had been created variety of a samples of electroinsulating varnish with different percentage of filling with nanoparticles. Experimental material is epoxy resin NH91 LV filled by Al2O3 nanoparticles.
34

Využití metamateriálů pro zlepšení parametrů antén / Improving antenna parameters by the application of metamaterials

Šporik, Vladimír January 2009 (has links)
The thesis is focused on the design of a planar resonant-type antenna, which exploits a proper combination of left- and right-handed properties of transmission lines. This transmission line is called CRLH TL and is based on Sievenpiper mushroom structure. Advantages of the proposed antenna concept are demonstrated by a detailed comparison of its basic properties with the properties of a conventional patch antenna.
35

Studium elektrických vlastností kompozitních materiálů / Study of electric properties of composite

Macháček, Miroslav January 2009 (has links)
This work deals with issues of composite materials. The general aim is to observe how the amout of filling infuence dielectric spectrum which is measured on prepared samples. For this purpose had been created variety of a samples with different percentage of filling with mica. Measured values had been compared with theoretically values, determinated using mixture formulas.
36

Koincidenční detektor FM - laboratorní přípravek / FM Coincidence Detector - Laboratory Equipment

Mlčoch, Jiří January 2009 (has links)
This work is aimed at an analysis of frequency demodulation, design, simulation, and construction of a coincidence demodulator. Chapter 1 explains the basic characteristics of frequency modulated (FM) signals and provides an overview of the required signal bandwidth, the signal spectrum, and the signal-to-noise ratio after demodulation. Chapter 2 describes each type of FM demodulator separately, and it includes all significant types of demodulator for FM radio broadcast. The function of the coincidence demodulator and its characteristics are explained in detail. Chapter 3 contains a theoretical solution of the phase shift network. Calculated values of the circuit elements are verified by simulation with a view to the total harmonic distortion of the demodulator output signal. Chapter 4 describes the front-end circuit of the receiver. Here, the filter design and the mixer circuit description are provided. The final part of the thesis presents the applicable laboratory task.
37

Návrh řiditelných diferenčních filtrů s proudovými aktivními prvky / Design of adjustable fully-differential filters with current active elements

Polášek, Lubomír January 2010 (has links)
The master thesis deals with design of the fully differential frequency filters working in the current mode and is focused on possibilities of the natural frequency and the quality factor adjustment. At the beginning, there is a brief description of frequency filters and active elements (MO-CF, FD-CF and DACA), which are used in the thesis. Furthermore, simplified signal flow graphs design method and transformation of passive and active elements to the differential structures are described. The designs of four differential circuitries which provide possibility of tuning the natural frequency or quality factor by the gain of the DACA element are shown in the thesis. Simulation results made in OrCAD program with help of third-order models are included. The practical implementation of the differential frequency filter for tuning of the natural frequency by the DACA elements is shown in the last chapter.
38

Sledování elektrických vlastností nanokompozitních materiálů / Study of electrical properties of nanocomposites

Ovsík, Jiří January 2012 (has links)
The present work deals with the electrical properties of nanocomposite materials. Samples for the experiment are made of epoxy resin as a matrix and oxides TiO2, Al2O3, WO3, SiO2 as nanofillers in 0.5 and 1 percent performance. The experimental samples are measured in temperature and frequency dependence of relative permittivity, dissipation factor, rezistivity and are broken down by the influence of filler on the electrical properties of the polymer. Attention is also paid to the mechanical properties of nanocomposites.
39

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
40

Elektrické vlastnosti nanokompozitů / Study of electric properties of nanocomposites

Libra, Miroslav January 2013 (has links)
The present master´s thesis deals with the electrical properties of nanocomposite materials. Samples for the experiment are made epoxi resin and oxides TiO2 and Al2O3 as nanofillers in different percent performace. The samples nanocomposites are measured temperature dependence of the resistivity inside, dissipation factor and relative permittivity. It discusses the effect of the filler on the resulting electrical properties of the polymer.

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