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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

Fázové transformace v hořčíkových slitinách typu MgZnAl. / Phase transformation in magnesium MgZnAl-based alloys

Kodetová, Veronika January 2016 (has links)
In the present work, there was analyzed thermal evolution of the phase transformation in the MgZnAl and MgZnAlCa alloys with different concentration of the Zn and Ca. The grains were occupied by the phase with quasicrystaline icosaedral structure in the as-cast alloys and after isochronal annealing up to 240 řC. The thermal measurements revealed two exothermic effects in the MgZnAl alloy and three exothermic effects in the MgZnAlCa alloy during linear heat treatment in the temperature range of 100 - 250 řC. In agreement to the thermal response, two and three stages of electrical resistivity decrease were observed in the same temperature range. The lower thermal changes, absolute resistivity changes and microhardness were observed in the alloy with Ca-addition and lower concentration of Zn.
12

Mechanizmy aktivace a modulace vaniloidních TRP receptorů / Mechanisms of activation and modulation of vanilloid TRP channels

Boukalová, Štěpána January 2014 (has links)
Štěpána Boukalová Mechanisms of activation and modulation of vanilloid TRP channels TRPV1 and TRPV3 are thermosensitive ion channels from the vanilloid subfamily of TRP receptors. TRPV1, which is primarily expressed in nociceptive sensory neurons, is an important transducer of painful stimuli and is also involved in the detection of noxious heat. TRPV3 is expressed mainly in the skin where it regulates proliferation and differentiation of keratinocytes. Similarly to voltage-dependent potassium (Kv) channels, TRP receptors are comprised of four subunits, each with six transmembrane segments (S1-S6). Using mutational approach, we tried to elucidate the role of S1 in TRPV1 functioning. Our results indicate that the extracellular portion of S1 plays a crucial role in TRPV1 gating. TRPV1 channels with a conservative mutation of positively charged residue in this region (R455K substitution) were overactive. However, they were neither activated nor potentiated by low pH; on the contrary, protons stabilized the closed conformation of this mutant channel. Very similar phenotypic properties were found in other TRPV1 mutants with substitution in S4/S5-S5 region and in the pore helix. In Kv channels, extracelular portion of S1 forms a small contact surface with the pore helix, which allows efficient transmission of...
13

Diverzita a rozšíření druhového komplexu Euastrum humerosum / didelta (Desmidiales) / Diversity and distribution of the Euastrum humerosum / didelta (Desmidiales) species complex

Kupčíková, Eva January 2019 (has links)
From 23 European and North American strains Euastrum humerosum/didelta species complex (Desmidiales) I have obtained 3 lineages in molecular marker trnGucc group II intron. I did not acquire significant and homogenous results in SSU intron. It is probable that the lineages of trnGucc intron are very young. SEM revealed one central pore in cell wall and five bulges. The lineages were significantly different in their shape and dimensions. The lineages differentiated mainly in their length and breadth of the cells. The lineages inside morphotype E. humerosum differentiated in shape and dimensions of the polar lobe. The lineages inside morphotype E.didelta differentiated in shape and dimensions of the neck. That was ascertained using the geometric morphometrics with the measuring. Linear discriminant analysis of the desmids from literature revealed that is possible to partly discriminate groups of the varieties (E. humerosum var. parallelum and E. didelta in lineage A; two formae E. didelta f. val Piora and E. didelta f. latior in lineage B; E. didelta var. inermiforme and E. humerosum var. affine in lineage C). Key words: desmids, species, hidden diversity, molecular phylogenetics, geometric morphometrics, Euastrum, scanning electron microscopy
14

Plazmová modifikace materiálů pro medicinální účely / Plasma modification of materials for medical purposes

MATĚJÍČEK, Jan January 2016 (has links)
This diploma thesis deals with the ongoing research under the auspices of the Department of Applied Physics and Technics Faculty of Education, University of South Bohemia in České Budějovice, in which the author of the work was actively participated. The thesis is divided into theoretical and experimental part. The theoretical part contains information from natural polymers, especially cellulose, plasma technology and infrared spectrometry. The subject of the experimental part of the thesis is research that deals with the functionalization of cellulose using a microwave plasma discharge on the apparatus CX-22. In the present research was also conducted to process optimization of functionalization with the liquid precursor hexamethyldisiloxane (HMDSO).
15

Diverzita a rozšíření druhového komplexu Euastrum humerosum / didelta (Desmidiales) / Diversity and distribution of the Euastrum humerosum / didelta (Desmidiales) species complex

Kupčíková, Eva January 2018 (has links)
From 23 European and North American strains Euastrum humerosum/didelta species complex (Desmidiales) we have obtained 3 lineages in molecular marker trnGuuc group II intron. We did not acquire significant and homogenous results in SSU intron. It is probable that the lineages are very young. The lineages were significantly different in their shape and dimensions. We used the geometric morphometrics with the measuring of the lengths and breath of the semicells, isthmus and their ratios. The lineages differentiated in their dimensions and shape variable polar lobes and neck. SEM revealed the one central pore in cell wall on the contrary, with variant E. didelta var. bengalicum, which has two pores according the literature records. Key words: desmids, species, hidden diversity, molecular phylogenetics, geometric morphometrics, Euastrum, scanning electron microscopy
16

Nové materiály pro Li-iontové baterie pracující na principu konverze / New materials for Li-ion batteries with conversion mechanism

Petr, Jakub January 2014 (has links)
This thesis is interested in new materials for lithium – ion batteries. Two different samples were investigated, one intercalation and one conversion cathode material. The theoretical part is focused to the structure of cells, their advantages and disadvantages compared to other secondary batteries. Also other materials used in batteries are described. The practical part describes the preparation of cathode materials for subsequent testing by scanning elektron microscopy and thermogravimetric analysis. In conclusions two different materials were evaluated and compared with each other.
17

Měření indexu lomu a morfometrie živých buněk pomocí koherencí řízeného holografického mikroskopu / Measurement of refractive index and morphometry of living cells by coherence-controlled holographic microscopy

Vodičková, Marie January 2018 (has links)
This master’s thesis deals with the design of methodology for measurement of refractive index and thickness of living cells by coherence-controlled holographic microscope. The theoretical part summarises the holographic microscopy and its development at IPE FME BUT in Brno. The thesis focuses on the multimodal holographic microscope, its description, the principle, the procedure of work and data processing. Confocal microscopy is also described, which serves to compare the acquired values with the proposed methodology. The last part of the theoretical part deals with the testing of statistical hypotheses, which is needed for the processing of measured data. Experiments were designed for the verification of methodology for determination of the refractive index and cell thickness. The experimental part of the thesis deals with the sample preparation and measurement. The procedure and results of the proposed experiments and their evaluation follows.
18

Vysoce uspořádané tenké vrstvy oxidu kobaltu pro modelovou katalýzu / Highly ordered cobalt oxide thin films for model catalysis

Ronovský, Michal January 2020 (has links)
Hydrogen processing is becoming increasingly important not only in the production of electricity but also during its accumulation. One of the energy storage options are liquid organic hydrogen carriers (LOHC). The main drawback of LOHC is the need for a large amount of thermal energy to release molecular hydrogen. We can bypass this issue using heterogeneous catalysis by transferring hydrogen from LOHC to acetone and using the produced 2-propanol (IPA) in the fuel cell. This innovative strategy of getting electri- cal energy from LOHC can be potentially energetically neutral. In this work, we studied highly ordered Co3O4(111) model catalysts for IPA oxidation in the as-prepared state and enhanced with platinum (Pt) nanoparticles. Catalysts were prepared by Physical Vapour Deposition (PVD) and further investigated by means of Low Energy Electron Diffrac- tion (LEED), X-ray Photoelectron Spectroscopy (XPS), Scanning Tunneling Microscopy (STM) and Temperature Programmed Desorption (TPD). The nucleation process of Pt on the as-prepared Co3O4(111) surface was studied by depositing low amounts 0.04 and 0.13 monolayer (ML) of Pt, that create clusters as small as 2 or 3 atoms with no need for a special nucleation site. We have identified the formation of Pt-induced defects in the atomically flat cobalt oxide...
19

Povrchová analýza nanokompozitu xGnP/PEI / Surface analysis of xGnP/PEI nanocomposite

Červenka, Jiří January 2012 (has links)
Tato Diplomová práce se zabývá povrchovou analýzou nanokompozitní folie polyetherimidu (PEI) vyztuženého exfoliovanými grafitickými nanodestičkami (xGnP). Analyzovány byly take vzorky nevyztužené PEI folie a samostatné nanodestičky. Vzorky nanokompozitu a PEI folie byly plazmaticky leptány s využitím argonového plazmatu po dobu 1, 3 a 10 hod. Skenovací elektronová mikroskopie (SEM) byla použita pro charakterizaci samostatných nanodestiček rozptýlených na křemíkovém substrátu, původních či leptaných vzorků PEI folie a nanokompozitu. Nanodestičky byly identifikovány při povrchu leptané nanokompozitní folie. Mikroskopie atomárních sil (AFM) byla použita pro zobrazení povrchové topografie separovaných nanodestiček a odkrytých destiček při povrchu leptaného kompozitu. Povrchová drsnost (střední kvadratická hodnota, vzdálenost nejnižšího a nejvyššího bodu) leptaného nanokompozitu narůstala s prodlužující se dobou leptání. Akustická mikroskopie atomárních sil (AFAM) byla použita pro charakterizaci elastické anizotropie leptaných kompozitních vzorků. Nanoindentační měření umožnila charakterizaci lokálních mechanických vlastností PEI a nanokompozitních folií.
20

Registrace autofluorescenčních obrazů sítnice / Registration of the autofluorescence images

Říha, František January 2008 (has links)
The autofluorescence images of the retina, which are obtained by laser scanning confocal ophthalmoscope Heidelberg Retina Angiograph (HRA), are used for early glaucoma diagnosis. Glaucoma is caused by gradual damage of the optic nerves, which leads to the failing of eyesight and can even cause its complete loss. HRA system is used to obtain a set of retinal images, where every image represents certain segment of retina. This thesis describes image registration methods for retinal image mosaicing. The tested registration methods are based on the global function of similarity or the landmarks detection. As landmarks, the blood vessel bifurcations are considered.

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