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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.
11

Počítačové modelování a analýza dielektrických spekter / Computer modelling and analysis of dielectric spectra

Frybert, Jan January 2011 (has links)
Complex permittivity, frequencies area, empirical functions of distribution of relaxation time, modelling, nonlinear regression, Levenberg-Marquardt algorithm.
12

Počítačové modelování a analýza dielektrických spekter / Computer modelling and analysis of dielectric spectra

Frybert, Jan January 2011 (has links)
Complex permittivity, frequencies area, empirical functions of distribution of relaxation time, modelling, nonlinear regression, Levenberg-Marquardt algorithm.
13

Dielektrické vlastnosti epoxidových pryskyřic / Dielectric properties of epoxy resins

Matoušová, Klára January 2019 (has links)
This diploma thesis deals with the fundamental properties of epoxide mixtures, as determining of these fundamental properties of epoxide mixtures could in the case of favorable results lead to diminishing the amount of defects in epoxide-embedded instrument transformers. As the influence of effects in the manufacturing process of transformers causing poor quality is very extensit, the biggest emphasis is laid capitally on the influence of the epoxide casting mixture composition. The thesis describes the manufacture technology including used methodics and materials. The compositions of epoxide resins and the mechanisms of their curing. Also, the definitions of fundamental properties of dielectric materials and the description of diagnostic methods used to relative permitivity, dissipation factor and inner resistivity are included. suitable casts of acquired samples were set and dried out within the experimental part, followed by measurement of fundamental electrical properties in temperature and frequency relations. Hereafter a comparison of individual samples and the evaluation of their electrical properties will be carried out.
14

Vliv nanočástic na vlastnosti elektroizolačních materiálů / Influence of nanoparticles on the properties of electroinsulating materials

Sedláček, Michal January 2009 (has links)
This work deals with influence nanoparticles, as fillers of polymer, to electrical properties dielectric composite materials. Addition of just a few weight percent of nonofillers has profound impact on the physical, chemical, mechanical and electrical properties orf polymer. Simultaneously is focused on production and diagnostics by the relaxation spectroscopy and measure internal resistance. Examination material is epoxy resin TSA 220S filled Al2O3 and SiO2 nanoparticles.
15

Účinky elektrického namáhání na vlastnosti elektroizolačních materiálů / Effects of electrical stress on properties of electrical insulating materials

Hangya, Josef January 2014 (has links)
Diploma thesis treat of effect of direct, alternate and pulse electrical stress on the properties surveyed electrical insulating material. Object of this experiment is crystalline high-density polystyrene QUINN PS. To monitor the stress is used the method of dielectric relaxation spectroscopy. Under examinations are the resultant dielectric spectra, which constitute the frequency dependencies of components of complex permitivity. Samples of the selected material are exposed to effects of alternate and pulse electrical stress on the different intensities of the electric field. In the direct field are then monitored absorption characteristics and specific volume resistance of the samples.
16

Vlastnosti aprotických elektrolytů pro lithno-iontové akumulátory / Properties of aprotic electrolytes for lithium-ion accumulators

Staněk, Vladimír January 2014 (has links)
The present work deals with the properties of suitable electrolytes for lithium-ion batteries. The first part described in the current issue of electrolytes for lithium-ion batteries, types of solvents and their properties and methods of measurement properties. The second part is devoted to the measurement of the properties of solvents and electrolytes such as relative permittivity, density and viscosity. Measurement of relative permittivity was focused on the measurement of the solvent mixture with varying the percentage of the solvent. Viscosity and density were measured on a solvent with a lithium salt added (final electrolyte).
17

Flíčková anténa s budicí štěrbinou / Centre-fed microstrip patch antenna

Jireček, Martin January 2011 (has links)
Systems with extreme bandwidth are part of advanced modern systems at radio high capacitive communication. Originally this technology was intended for radar scan. Thanks to wide frequency band had radar possibility „ see" a behind crimp, e.g. behind woody partitions etc . To his noise immunity, fail safe tapping plus small wattage heftiness began use for datal systŽm function. If is elementary antenna compound from coaxial probe and shorting outlet, it is possible use to actuating separate narrow slot placed in the middle of incandescent dabs. Impedance and radiating characteristics conventionally plumbed phlobaphene antennae excited tape lead and suggested microstrip phlobaphene antennae are experimentally explored plus collated. Explored is so and effect changes slotted longitude slot on characteristics elementary antenna.

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