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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.
1

Je Pseudotsuga menziesii dalším invazním druhem v NP České Švýcarsko? / Pseudotsuga menziesii, the new potential invasive species in the České Švýcarsko National Park?

DUDÍKOVÁ, Tereza January 2009 (has links)
Pseudotsuga menziesii, naturalized conifer from the North America, has been planted in the area of the present-day České Švýcarsko National Park (Czech Republic) from 19th century. These surveys concentrate on the question of environmental preferences of seedlings and saplings of Pseudotsuga, and characterize potential distance distribution of this tree. In conclusion, Pseudotsuga is still only naturalized species, but danger of becoming to be invasive is very high.
2

Studium vlnově-částicových interakcí v kosmickém plazmatu / Analysis of wave-particle interactions in space plasmas

Černý, Miroslav January 2011 (has links)
This work deals with the linear analysis of plasma waves, especially with the methods of solution of a hot plasma dispersion relation. There are cited some results achieved in the space plasma research and mapped current numerical methods of their analysis. Besides, this work introduces a new numeric procedure, computer code PDRS (Plasma Dispersion Relation Solver), which allows finding solution of a dispersion function of a cold or hot plasma with general distribution function. It also demonstrates the usage of the PDRS methods on real examples of waves in space plasma based on the spacecraft Cluster measurement.
3

Možnosti modelování heteroskedasticity s aplikacemi v neživotním pojištění / Some possibilities of heteroskedasticity modeling with applications to non-life insurance

Pavlačková, Petra January 2014 (has links)
Title: Some possibilities of heteroskedasticity modeling with applications to non-life insurance Author:Petra Pavlačková Department: Department of Probability and Mathematical Statistics Supervisor: Ing. Zimmermann Pavel, Ph.d. Abstract: This thesis deals with the possibilities of modeling heteroskedasticity using generalized linear models. It summarizes the assumption for these models and their application in practice. It shows the practical need for these models. Furthermore, the thesis deals with the modeling of variance using other methods than generalized lienar models - such as generalized additive models or local regression. Comparison of methods is graphically demonstrated. Keywords: Dispersion parameter, variance function, Joint modelling of mean and dispersion
4

Lepení materiálů na bázi dřeva pomocí mikrovlnného záření

Hlučka, Marek January 2014 (has links)
The thesis delas with the influence of microvawe radiation on shear strength. For this experiment were selected two of our most common wood species which are used in furniture, construction and other industries and fields. Namely spruce wood and beech wood. All species were bonded by water-based dispersion adhesive (coating 150 g/m
5

Porovnání metod hodnocení pevnosti desek z masivního dřeva

Drga, Tomáš January 2015 (has links)
The main aim of the thesis is the comparison of methods that are focused on assessment of solid woods boards' strength. The assessment is considered from a point of view of normative methods and it is determined at industrial oak and beech solid wood panels with PVAC dispersion glue. The thesis consists of two main parts. The first part is theoretical and it is focused on solid wood materials, wood bonding, technological factors and circumstances that influence the quality of adhesive joints. There are also mentioned basic types of adhesives used in furniture and wood industry as well as overview of standards dealing with quality of adhesive joints of wood materials in the theoretical part. The theoretical knowledge is used in the second part where is the methodology created. The methodology helps to find out the density, shear bond strength and percentage violation of adhesive joints of test samples. Finally, the results of analytical part are statistically evaluated and mutually compared and also compared with specialized literature.
6

Příprava a charakterizace magnetických nosičů z hypersíťovaných polystyrenových mikročástic a jejich použití v biosenzoru / Preparation and Characterization of Magnetic Carriers from Hypercrosslinked Polystyrene Microspheres and their Application in a Biosensor.

Šálek, Petr January 2012 (has links)
With the aim to develop and characterize a functionalized highly magnetic polymer carrier of micrometer size and of a narrow particle size distribution that will be suitable for biological application, hypercrosslinked microspheres were prepared. Simultaneously, the relation between structure and properties of product was observed. Condition of dispersion polymerization were optimized to obtain starting monodisperse poly(styrene-co-divinylbenzene) [P(St-DVB)] microspheres. The P(St-DVB) microspheres of different degree of crosslinking were prepared and effect of some polymerization parameters such as type of solvent, initiator, concentration and mode of DVB addition on morphology, size and particle size distribution were investigated. The starting microspheres were hypercrosslinked to obtain microporous inner structure. Hyperosslinked particles had very large specific surface area (> 1000 m2/g) and a high content of micropores (ca. 0.6 ml/g). First, P(St-DVB) microspheres were chloromethylated using three different chloromethylation agents to regulate their porous properties. Hypercrosslinking was achieved by the addition of stannic chloride as a catalyst and by increasing a temperature. The hypercrosslinked microspheres were then functionalized with sulfo- or aminogroups. The functional groups captured precipitated iron oxide inside the porous structure of the microspheres and also served as a reactive site for intended immobilization of the protein. A solution of ferrous and ferric chloride was imbibed under vacuum into the porous structure and the iron oxide was precipitated by an aqueous ammonia solution. Finally, the magnetic functionalized hypercrosslinked micropsheres were integrated into a biosensor for qualitative detection of ovalbumin.
7

Vliv použité báze lepidla na kvalitu dýhovaných nábytkových dílců

Kotálová, Veronika January 2017 (has links)
Submitted diploma thesis deals with the influence of the adhesive base to quality of veneered furniture parts and follows the requirements of applicable standards for testing. The most frequently used materials in furniture were selected to verify the quality. As substrate samples were chosen 18 mm thick chipboards and as a decorative material were chosen beech veneers with a thickness of 0.6 mm. To test the suitability of adhesive compositions for veneering furniture components were selected adhesive mixtures based on condensation adhesives types (urea-formaldehyde and melamine-urea-formaldehyde adhesives) and dispersion (PVAc), and the resulting adhesive compositions were made from various types of adhesives in specified ratio (60 : 40, 75 : 25 and 85 : 15). The test samples were veneered with the same adhesive coating, which was 150 g/m2. Individual test samples were divided into groups according to the type of used adhesive, pressing temperature and pressing time. These test samples were tested after completion of the adhesive file, compression and conditioning. Quality of furniture parts was assessed in terms of physico-mechanical properties of the finished surface quality of furniture components after the completion of the surface treatment of the test samples with spraying by water-based and acrylate-polyurethane coating. The result of this thesis is the determination of depending of adhesives types to quality of veneered furniture parts. Another result is comparing of different finishes types to quality of veneered furniture parts.
8

Vliv polarizační disperze na chybovost optického kanálu / The impact of polarization mode dispersion on error-rate of optical fibre link

Dorociak, Petr January 2008 (has links)
Master’s thesis engages in the impact of polarization mode dispersion on optical communication system. Polarization mode dispersion is mathematically described by Stoke’s and Jone’s space and ensure the theoretic causes of the rise of polarization mode dispersion that are divided on the external and internal effects. On the basis of these effects grow up a differential group delay (DGD) which makes causes that individual polarization modes have between them a time delay and limitation of maximum bit rate. Then master´s thesis analyses the influence of the polarization mode dispersion on the pulse enlargement and on the modulation signal. In this work, there are described the most applicated optical modulation formats. Polarization mode dispersion has also influence on the bit error rate of optical fibre link and closing of eye diagram too. Eye diagram is used to view the transmission characteristics and diagnoses the channel errors. Eye diagram is connected with the definitions as a bit error rate (BER) and signal-to-noise ratio (SNR) that are explained in this work too. Following the gained experiences it was designed an useful graphic interface to display the effect of the polarization mode dispersion on the transmitted signal. Realization of the graphic interface is created in the program MATLAB. In Matlab-Simulink are created six models according to the kind of modulations with characteristic AWGN (Additive White Gaussian Noise) channel. Program was tested for a typical values. In all calculations it is counted only with the losses that are caused by the polarization mode dispersion. It is not calculated with the losses that are caused by a chromatic dispersion and attenuation. At the end of this work are evaluated all types of modulation formats depending on the polarization mode dispersion, optical fibre length, price and complexity of the realization. Atteined results of my master’s thesis are compared with two foreign articles.
9

Rychlé interferenční vlny a 1D seismické modely kůry / Rychlé interferenční vlny a 1D seismické modely kůry

Vackář, Jiří January 2012 (has links)
A recent shallow earthquake in the Corinth Gulf, Greece (Mw 5.3) generated unusual long-period waves (periods > 5 seconds) between the P- and S-wave arrival. The 5-second period, being significantly longer than the source duration, indicates a structural effect. Observed seismograms were examined by methods of the frequency-time analysis. Disper- sion curves of the fast long-period (FLP) waves indicated group velocities ranging from 3 to 5.5 km/s for periods between 4 and 10 s, respectively, with large variations among the stations. The generalized dispersion curve splits into two major strips, probably related to lateral variations of the crustal structure. Forward simulations for several existing crustal models were made. A few partially successful models served for a sensitivity study, which showed that the FLP wave seemed to be mainly due to the low-velocity layers in the uppermost 4 kilometers of the crust. Finally the shallow crustal structure was retrieved by inverting observed seismograms by Neighborhood algorithm. The inversion confirmed that the FLP wave in seismograms at more than a single station cannot be explained with a 1-D crustal model. The path-dependent models provided a partial explanation for the strips revealed in the experimental dispersion curves. An alternative explanation is by...
10

Konstrukce pseudoskalárních mezonových amplitud v chirální poruchové teorii za použití disperzních metod / Construction of pseudoscalar meson amplitudes in chiral perturbation theory using a dispersive approach

Zdráhal, Martin January 2012 (has links)
Title: Construction of pseudoscalar meson amplitudes in chiral perturbation theory using a dispersive approach Author: Martin Zdráhal Department: Institute of Particle and Nuclear Physics, Faculty of Mathematics and Physics, Charles University in Prague Supervisor: RNDr. Jiří Novotný, CSc. Abstract: We have developed a method enabling a construction of two-loop 2 → 2 scatter- ing amplitudes of pseudoscalar mesons based on the dispersion and the unitarity relations. This method is illustrated on the construction of the amplitudes of all such processes in chiral perturbation theory in isospin limit taking into account strong interactions only. Then it was used for the construction of ππ scattering amplitudes and of K → 3π and η → 3π decay amplitudes including isospin breaking effects induced by different masses of the particles belonging to the same isomultiplet. These parametrizations are prepared for various phenomenological analyses of the ππ scattering lengths and of the isospin breaking effects, both of which could pro- vide us important information for the understanding of quantum chromody- namics at low energies. Finally, we have performed the phenomenological study of η → 3π decay and obtained a value of the quark mass ratio 1/R = (md − mu)/(ms − ˆm). Our conservative estimate is R = 39.6+2.5 −5.1....

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