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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

Microscopy techniques for studying polymer-polymer blends

Mattsson, Sandra January 2019 (has links)
Semiconductors are used in many electronic applications, for example diodes, solar cells and transistors. Typically, semiconductors are inorganic materials, such as silicon and gallium arsenide, but lately more research and development has been devoted to organic semiconductors, for example semiconducting polymers. One of the reasons is that polymers can be customized, to a greater extent than inorganic semiconductors, to create a material with desired properties. Often, two polymers are blended to obtain the desired function, but two polymers do not usually result in an even blend. Instead they tend to separate from each other to varying degrees. The morphology of the blend affects the material properties, for example how efficiently it can convert electricity to light. In this project, thin films consisting of polymer blends were examined using microscopy techniques for the purpose of increasing our understanding of the morphology of such blends. One goal was to investigate whether a technique called correlative light and electron microscopy can be useful for examining the morphology of these films. In correlative light and electron microscopy, a light microscope and an electron microscope are used in the same location in order to be able to correlate the information from the two microscopes. The second goal was to learn about the morphology of the thin films using various microscopy techniques. The polymers used were Super Yellow and poly(ethylene oxide) with large molecular weight. Super Yellow is a semiconducting and light-emitting polymer while poly(ethylene oxide) is an isolating and non-emitting polymer that can crystallize. In the blend films, large, seemingly crystalline structures appeared. The structures could be up to 1 mm in the lateral direction, while the films were only approximately 170 nm thick. These structures could grow after the films had dried and their shapes were similar to those of poly(ethylene oxide) crystals. Consequently, there is reason to believe that it is the poly(ethylene oxide) that makes up the seemingly crystalline structures, but the structures also emitted more light than the rest of the film, and Raman spectroscopy showed that there was Super Yellow in the same location as the crystals. Among the microscopy techniques used, phase contrast microscopy was particularly interesting. This method visualizes differences in optical path length and was useful for studying polymer blends when the polymers have different indices of refraction. Correlating light and electron microscopy showed that there was a pronounced topographical difference between the seemingly crystalline regions and the rest of the thin film. Light microscopy has a limited resolution due to diffraction, but as long as the resolution of the light microscope is sufficient for seeing phase separation, correlative light and electron microscopy turned out to be a good method for studying the morphology of thin films of polymer blends. / Halvledare är viktiga för många elektroniska ändamål eftersom de kan användas till exempelvis dioder, solceller och transistorer. Traditionellt används inorganiska halvledande material som kisel eller galliumarsenid, men på senare tid har allt mer forskning och utveckling inriktat sig mot organiska (kolbaserade) halvledare, såsom halvledande polymerer, bland annat eftersom det i högre utsträckning går att skräddarsy de organiska materialen så att de får önskvärda egenskaper. Ofta blandas två polymerer med varandra för att skapa ett material med nya egenskaper som är önskvärda, men två polymerer brukar inte blandas jämnt utan tenderar att separera från varandra i olika utsträckning. Hur blandningen ser ut (morfologin) påverkar materialets egenskaper, till exempel hur effektivt det omvandlar ström till ljus. Med syfte att öka förståelsen för hur morfologin ser ut hos en blandning av två polymerer, har detta projekt gått ut på att undersöka tunna filmer av polymer-blandningar med hjälp av mikroskopiska tekniker. Ett delmål var att ta reda på om en teknik som heter korrelativ ljus- och elektronmikroskopi är en bra metod för att undersöka morfologin hos dessa filmer. Vid korrelativ ljus- och elektronmikroskopi används både ett ljusmikroskop och ett elektronmikroskop på samma plats för att kunna korrelera informationen som de båda mikroskopen ger. Det andra delmålet var att undersöka vad de olika mikroskopi-teknikerna kan säga om morfologin hos de tunna filmerna. De polymerer som använts är Super Yellow och poly(etylenoxid) med hög molekylmassa. Super Yellow är en oordnad halvledande och ljusemitterande polymer medan poly(etylenoxid) är en isolerande och icke-emitterande polymer som kan kristallisera. I de blandade filmerna uppstod stora kristall-liknande strukturer som kunde vara upp emot 1 mm breda trots att filmerna bara var ungefär 170 nm tunna. Dessa strukturer kunde växa fram efter det att filmerna redan hade torkat och påminde i form om kristaller som kan bildas av poly(etylenoxid). Det finns alltså skäl att tro att det är poly(etylenoxid) som kristalliserats, men de kristall-liknande strukturerna visade sig emittera mer ljus än vad resten av filmen gjorde, och Raman-spektroskopi visade att det även fanns Super Yellow på samma plats som kristallerna. Bland de mikroskopitekniker som testades utmärker sig faskontrastmikroskopi, som visar skillnader i den optiska vägskillnaden (det vill säga faktisk vägskillnad multiplicerat med brytningsindex). Det visade sig vara en intressant teknik för att studera polymerblandningar när de båda polymererna har olika brytningsindex. Genom att korrelera ljus- och elektronmikroskopi visade det sig att det fanns en tydlig skillnad i struktur mellan de kristall-liknande områdena och resten av den tunna filmen. Ljusmikroskopi har begränsad upplösning på grund av ett fenomen som heter diffraktion, men så länge som ljusmikroskopets upplösning är tillräcklig för att se fasseparation visade det sig att korrelativ ljus- och elektronmikroskopi är en bra metod för att studera morfologin hos tunna filmer av polymerblandningar.
42

Temporální vztahy v českých barokních textech / Temporal relationships of Czech Baroque texts

MONDŘÍKOVÁ, Petra January 2013 (has links)
The presented dissertation addresses the issue of expressing temporary relations (the present and the past) in the texts of the authors of the Baroque period. The excerpt includes 44 works of historic literary output. The topic is based on a semantic definition of temporal relationships in the Baroque language and interferes with the paratactic and hypotactic method of expression. Within the scope of paratactic connection of syntactic units, we analyze phrasal connections (the connection of main clauses and the connection of paratactic subclauses), text and phrasal connections, within the scope of hypotactic concentration mainly the relationship of the main and subordinate adverbial clauses of time. The classification according to various paratactic and subordinating conjunctions is led by the effort to obtain a comprehensive overview of the possible ways to express temporal relationships. The aim of the work is to contribute to an analytical examination of the syntactic language level of the Baroque period and to confirm the hypothesis of intact continuity of the language development between the humanistic, Baroque and National Revival periods.
43

Vztah vyšších chromatinových struktur a genové umlčování / The relationship between higher order chromain structure and gene silencing

Šmigová, Jana January 2012 (has links)
No description available.
44

Strukturně-funkční organizace buněčného jádra.Mikroskopická analýza jaderných subkompartmentů. / Structure-function organization of the cell nucleus.Microscopical analysis of nuclear subcompartments.

Jůda, Pavel January 2015 (has links)
Pavel Jůda - Abstract The cell nucleus is a complex cellular organelle. The nucleus and nuclear processes are organized into functionally and morphologically separated nuclear subcompartments. This thesis is particularly concerned with the three following nuclear subcompartments: sites of DNA replication, Polycomb bodies and nuclear inclusions constituted of inosine monophosphate dehydrogenase 2 (IMPDH2). First, we examined the relationship between MCM proteins and DNA replication. Using immunofluorescent labeling of cells extracted prior fixation and applying cross-correlation function analysis, we showed that MCM proteins are present at the sites of active DNA synthesis. Our results contributed to the solving of the first part of so-called MCM paradox. Second, we studied the structural basis of the Polycomb bodies. Based on fluorescence microscopy studies, Polycomb bodies have been considered to be the nuclear subcompartments formed by the accumulation of Polycomb proteins in the interchromatin compartment. In our work, using correlative light electron microscopy and experimental changes in macromolecular crowding, we clearly showed that a Polycomb body is a chromosomal domain formed by an accumulation of heterochromatin structures, rather than a typical nucleoplasmic body. Third, we were interested in...
45

Posouzení efektivity kapitálového trhu a výběr vhodné investiční strategie / The Examination of the Capital Market´s Efficiency and the Selection of Suitable Capital Strategy

SLÁDKOVÁ, Petra January 2010 (has links)
In my diploma I analyzed the USA capital market. I concentrated on 5 representative branches of this market - the biotechnology, the food industry, the car industry, the mining and the finances. 12 companies, which quote their share of stocks in the american capital market, were choosed. I tested the efficiency of this capital market and tried to establish the rate of this market´s efficiency. Later the best strategy was added to the rate of capital market´s efficiency. I counted the average decree, the standard deviation, the variation coefficient, the {$\alpha$} coefficient and {$\beta$} coefficient at the choosed share of stocks. I accomplished the correlative and the runs testing, which were supposed to certify the efficiency of market. The certain anomalies as The Day of the Week Effect, The January Effect and The Size Effect were investigated in more detail. Further I was considering if either the active or the passive strategy should have been used. I concluded that the active strategy is better for investors in times of the financial crisis. I also analyzed P/E ratio at choosed companies. The performated testing shows that the american market of shares is effective, it has the form of low efficiency peak-form efficient markets hypothesis.
46

The secondary adjustment on transfer pricing, notes about its nature and poor regulation in Peru / El ajuste secundario en materia de precios de transferencia, notas sobre su naturaleza y deficiente regulación en el Perú

Tartarini Tamburini, Tulio 12 April 2018 (has links)
This article addresses the subject of secondary adjustment on transfer pricing, focusing on its nature and its regulation in Peru. To do this, the author explains the concept and purpose of transfer pricing and also elaborates some terminological precisions concerning adjustments on transfer pricing, defining the primary adjustments, the compensating ones, the correlative ones and, in more depth, the secondary ones. Likewise, the author explains the way secondary adjustments of transfer prices are regulated by the Peruvian Income Tax Law. / El presente artículo aborda la temática del ajuste secundario en materia de precios de transferencia, enfocándose en su naturaleza y su regulación en el Perú. Para ello, el autor explica el concepto y la finalidad de los precios de transferencia, así como también realiza algunas precisiones terminológicas en materia de ajustes de precios de transferencia, definiendo los ajustes primarios, los compensatorios, los correlativos y, con mayor profundidad, los secundarios. Asimismo, el autor explica la manera en que los ajustes secundarios de los precios de transferencia están regulados en la Ley del Impuesto a la Renta peruana.
47

Étude et modélisation des transferts hydriques et thermiques au sein des matériaux inorganiques poreux : application aux matériaux du patrimoine bâti ancien, exemple de l'Hypogée des Dunes à Poitiers et de la crypte de l'abbatiale de Saint-Savin-sur-Gartempe / Study and modelling of hydric and thermal transfers within porous inorganic materials : application on the materials of the built heritage, example of the Hypogeum of Dunes in Poitiers and the crypt of the abbey-church of Saint-Savin-sur-Gartempe

Merckx, Benoit 22 November 2013 (has links)
Dans le cadre de la conservation et de la réhabilitation des bâtis anciens, les matériaux utilisés pour leur construction doivent être caractérisés vis-à-vis de leurs propriétés de transferts thermiques et hydriques. La première étape du travail de recherche a concerné la mise au point d'un capteur de conductivité thermique et de teneur en eau des matériaux inorganiques poreux (pierres, bétons, enduits) constitutifs des monuments. Les méthodes d’investigation doivent rester non intrusives. Dans cet objectif, la voie suivie a été d'adapter la mesure de conductivité thermique par une méthode simplifiée du fil chaud, précédemment développée pour les fluides corrosifs, aux pierres de taille utilisées dans le bâti ancien. Afin de transférer cette technologie des fluides vers les solides, plusieurs étapes ont été effectuées : (1) des mesures avec le fil intégré, (2) des mesures de surface, (3) estimation de l'influence de la rugosité de la surface et (4) utilisation de la méthode pour l'estimation de la teneur en eau des matériaux tests.La seconde étape de la recherche a consisté en deux suivis microclimatiques effectués sur deux sites historiques : l'Hypogée des Dunes et l'abbatiale de Saint-Savin-sur-Gartempe. Le travail de thèse a consisté à évaluer l'impact des travaux effectués sur les conditions climatiques dans l'hypogée, et à déterminer l’influence des variations climatiques sur la formation d'un voile biologique dans la crypte de Saint-Savin. Pour ce faire, l'analyse corrélatoire est appliquée au traitement des donnés climatiques. / In the framework of preservation and rehabilitation of ancient buildings, materials used for their construction must be characterized with regards to thermal and hydric transfer properties. The first stage of our research work focused on the development of a sensor of thermal conductivity and moisture content of the inorganic porous materials (stone, concrete, render) making up the monuments. The methods of investigation have to remain non-invasive. For this purpose, the path followed was to adapt the measure of thermal conductivity by a simplified transient hot-wire method, previously developed for corrosive fluids, to dressed stones used in built heritage. In order to transfer this technology from fluids to the solids, several stages were carried out : (1) measures with the integrated wire, (2) surface measures, (3) estimation of the influence of surface roughness and (4) use of this method to estimate the moisture content of several test materials.The second stage of the research consisted in the microclimatic monitoring of two historical sites: the Hypogeum of the Dunes in Poitiers and the crypt of the abbey church of Saint-Savin-sur-Gartempe. The thesis work sought to evaluate the impact of construction work performed in the Hypogeum on the internal climatic conditions, and to determine the influence of climatic variations on the formation of a biological veil in the crypt of Saint-Savin. To this aim, correlative analysis is applied to the treatment of climatic data.
48

Temporal Subordinators and Clauses in Early Modern English : Stability and Change

Rönnerdal, Göran January 2017 (has links)
My work is a corpus-based investigation of the use and development of temporal subordinators and clauses in Early Modern British English (EModE).  The focus of the project is on the forms, structure, meanings, and history of these subordinators and clauses. My primary aim is to analyse stability and change in temporal subordinators and clauses across the EModE period; second comes the study of linguistic features, such as aspect, tense, mood and modality, ellipsis and non-finite forms, positions, coordination, and subordination of the temporal clauses. In addition, I examine the progress of these subordinators, and WHEN in particular, across text categories, text types, and the sub-periods. Regarding temporal subordinators, I account for the use of simple, complex, and correlative forms. I also address alternative expressions of temporal subordinators such as the repetition and replacement of temporal subordinators. The influence of negation on the choice of subordinators, and the modification patterns of subordinators are also treated. Primary meanings of anteriority, simultaneity, and posteriority as well as secondary meanings of temporal subordinators are studied. I uncover the evolution of temporal subordinators and trace their various forms, as far back as possible to the Old English and Middle English periods. I also make some comparisons with Present-day English. The investigation is based on the EModE section of the computerized Helsinki Corpus of English Texts and the manual literary Major Authors Corpus which I designed for the purposes of the study. Consequently, my study is carried out within corpus linguistics methodology. All in all, the primary material yielded 3,269 instances of 17 different prototypical temporal subordinators, called sub-types.
49

Studium fotovoltaických nanostruktur mikroskopickými metodami / Study of photovoltaic nanostructures using microscopy methods

Hertl, Vít January 2018 (has links)
V této diplomové práci je nejprve ve zkratce uvedena teorie fyziky solárních článků, kde jsou zmíněny klíčové procesy ovlivňující účinnost konverze slunečního záření na elektrickou energii. Dále je předložena rešerše o fotovoltaických nanostrukturách (nanodráty, nanokrystaly), jejichž implementací je možné účinnost solárních článků zvýšit. V přehledu experimentálních technik ke zkoumání fotovoltaických nanostruktur je důraz kladen zejména na korelativní měření pomocí SEM a AFM, vodivostního AFM, měření EBIC a mikroskopické měření elektroluminiscence. V experimentální části jsou předloženy výsledky měření struktur mikrokrystalického křemíku, vzorku hetero-přechodového Si solárního článku s kontakty na zadní straně (IBC-SHJ z projektu NextBase) a V-pitů vzorku InGaN/GaN kvantových jam. Měření elektroluminiscence bylo provedeno na vzorcích III-V polovodičů (InGaP, GaAs). Byly vypočítány jinak těžko dostupné charakteristiky III-V tandemových solárních článků pomocí elektroluminiscence a srovnání vlastností IBC-SHJ zjištěných pomocí mikroskopického měření elektroluminiscence a EBIC. Provedením experimentů bylo zjištěno, jakým způsobem se dělí proud vybuzený svazkem elektronů mezi hrot AFM a vzorek mikrokrystalického křemíku.
50

Mechanické vlastnosti mikrostrukturních komponent anorganických materiálů / Mechanical Properties of Microstructural Components of Inorganic Materials

Wasserbauer, Jaromír January 2013 (has links)
Disertační práce se zabývá studiem strukturních a mechanických vlastností anorganických materiálů. Cílem je nalezení jednotlivých fází ve zkoumaném materiálu a hlavně lokalizace (mechanicky) nejslabšího místa, jeho ovlivnění a následně výroba materiálu o lepších mechanických vlastnostech. Z důvodu velkého množství použitých metod je základní teorie vložena vždy na začátku příslušné kapitoly. Taktéž z důvodu značného množství výsledků jsou na konci kapitol uvedeny dílčí závěry. Práce je rozdělena na tři části, kdy první se zabývá seznámením s možnostmi modelování mikro-mechanických vlastností a provedením experimentů umožňujících posouzení rozsahu platnosti některého modelu. V druhé části je provedeno shrnutí současných možností indentačních zkoušek pro měření mechanických vlastností strukturních složek betonu a praktické zvládnutí metodiky vhodné k užití pro výzkum materiálů zkoumaných domovským pracovištěm. V třetí části je navržena metoda identifikace nejslabších článků struktury anorganických pojiv a její ověření na konkrétním materiálu zkoumaném na domovském pracovišti. V této dizertační práci jsou použity tyto metody: kalorimetrie, ultrazvukové testování, jednoosá pevnost v tlaku, nanoindentace, korelativní mikroskopie a rastrovací elektronová mikroskopie s energiově disperzním spektrometrem. Dílčími výsledky jsou kompletní charakterizace cementových materiálů, upřesnění stávajících poznatků a nalezení optimálního postupu pro charakterizaci. Hlavním výsledkem je inovativní přístup vedoucí k pozitivnímu ovlivnění materiálu.

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