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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

Estudo teórico de nanoestruturas magnéticas em superfícies metálicas / Theoretical study of magnetic nanostructures on metallic surfaces

Igarashi, Ricardo Noboru 05 October 2012 (has links)
Neste trabalho, utilizamos o método de primeiros princípios RS-LMTOASA (Real Space - Linear Muffin-Tin Orbital - Atomic Sphere Approximation), baseado na Teoria do Funcional da Densidade (DFT Density Functional Theory) e implementado para o cálculo de estruturas magnéticas não colineares, para investigar as propriedades magnéticas de nanoestruturas adsorvidas em superfícies metálicas. Primeiramente, devido ao aparecimento de estruturas magnéticas complexas, foram estudadas nanoestruturas magnéticas depositadas em substratos ferromagnéticos. Foram consideradas nanoestruturas de Mn tais como nanofios adsorvidos, pirâmides e aglomerados adsorvidos e embebidos, com o tamanho destas nanoestruturas variando de dois até nove átomos depositados em Fe(001) e Fe(110). Nossos cálculos indicam uma interação de troca magnética de longo alcance entre os átomos de Mn-Mn e Mn-Fe. Além disto, a presença de uma forte dependência destas interações de troca magnética com o meio local, frustrações magnéticas e o acoplamento spin-órbita forneceram a possibilidade da presença de estruturas magnéticas complexas tais como, por exemplo, spin espiral e half-skyrmion. Por fim, com o objetivo de estudar nanoestruturas que podem apresentar altos valores de momento magnético, foram investigados nanofios de FexCo1-x adsorvidos em uma superfície de Pt(111) . Nossos resultados indicam que os momentos magnéticos de spin dos átomos de Fe e Co são independentes da concentração de Fe e apresentam valores superiores quando comparados aos das ligas FeCo bcc, enquanto que o momento magnético médio de spin do nanofio FexCo1-x varia linearmente com a concentração de Fe, comportamento este que é diferente da curva de Slater-Pauling observada na liga FeCo bcc. O momento magnético orbital médio do nanofio de FexCo1-x é monotonicamente decrescente com a concentração de Fe que se apresenta bastante diferente a monocamada FexCo1-x sobre Pt(111). / We use the first principles RS-LMTO-ASA (Real Space - Linear Muffin- Tin Orbital - Atomic Sphere Approximation) method, in the framework of the Density Functional Theory and implemented to calculate noncollinear magnetic structures, to investigate the magnetic properties of nanostructures adsorbed on metallic surfaces. First, due to presence of the complex magnetic properties, we investigated magnetic nanostructures deposited on a ferromagnetic substrate. We have considered a variety of nanostructures such as adsorbed wires, pyramids, at and intermixed clusters with sizes varying from two to nine atoms deposited on Fe(001) and Fe(110). Our calculations reveal the long-range nature of exchange interactions between Mn-Mn and Mn-Fe atoms. Moreover, the presence of the strong dependence of these interactions on the local environment, the magnetic frustration, and the effect of spin-orbit coupling lead to the possibility of realizing complex noncollinear magnetic structures such as helical spin spiral and half-skyrmion. Finally, we also investigated FexCo1-x nanowires deposited on Pt(111) surface aiming to investigate materials with large local magnetic moment. Our results reveal that the Fe and Co spin magnetic moment are independent of the Fe concentration with the enhancement of the spin magnetic moment when compared with the FeCo bcc alloys, while the average spin magnetic moment is a linear function of the Fe concentration. This is in contrast to the Slater-Pauling model observed in the FeCo bcc alloys. The average orbital magnetic moment shows a linearly decreasing behavior with the Fe concentration which is in contrast to the behavior of FexCo1-x monolayer on Pt(111) surface.
2

Estudo teórico de nanoestruturas magnéticas em superfícies metálicas / Theoretical study of magnetic nanostructures on metallic surfaces

Ricardo Noboru Igarashi 05 October 2012 (has links)
Neste trabalho, utilizamos o método de primeiros princípios RS-LMTOASA (Real Space - Linear Muffin-Tin Orbital - Atomic Sphere Approximation), baseado na Teoria do Funcional da Densidade (DFT Density Functional Theory) e implementado para o cálculo de estruturas magnéticas não colineares, para investigar as propriedades magnéticas de nanoestruturas adsorvidas em superfícies metálicas. Primeiramente, devido ao aparecimento de estruturas magnéticas complexas, foram estudadas nanoestruturas magnéticas depositadas em substratos ferromagnéticos. Foram consideradas nanoestruturas de Mn tais como nanofios adsorvidos, pirâmides e aglomerados adsorvidos e embebidos, com o tamanho destas nanoestruturas variando de dois até nove átomos depositados em Fe(001) e Fe(110). Nossos cálculos indicam uma interação de troca magnética de longo alcance entre os átomos de Mn-Mn e Mn-Fe. Além disto, a presença de uma forte dependência destas interações de troca magnética com o meio local, frustrações magnéticas e o acoplamento spin-órbita forneceram a possibilidade da presença de estruturas magnéticas complexas tais como, por exemplo, spin espiral e half-skyrmion. Por fim, com o objetivo de estudar nanoestruturas que podem apresentar altos valores de momento magnético, foram investigados nanofios de FexCo1-x adsorvidos em uma superfície de Pt(111) . Nossos resultados indicam que os momentos magnéticos de spin dos átomos de Fe e Co são independentes da concentração de Fe e apresentam valores superiores quando comparados aos das ligas FeCo bcc, enquanto que o momento magnético médio de spin do nanofio FexCo1-x varia linearmente com a concentração de Fe, comportamento este que é diferente da curva de Slater-Pauling observada na liga FeCo bcc. O momento magnético orbital médio do nanofio de FexCo1-x é monotonicamente decrescente com a concentração de Fe que se apresenta bastante diferente a monocamada FexCo1-x sobre Pt(111). / We use the first principles RS-LMTO-ASA (Real Space - Linear Muffin- Tin Orbital - Atomic Sphere Approximation) method, in the framework of the Density Functional Theory and implemented to calculate noncollinear magnetic structures, to investigate the magnetic properties of nanostructures adsorbed on metallic surfaces. First, due to presence of the complex magnetic properties, we investigated magnetic nanostructures deposited on a ferromagnetic substrate. We have considered a variety of nanostructures such as adsorbed wires, pyramids, at and intermixed clusters with sizes varying from two to nine atoms deposited on Fe(001) and Fe(110). Our calculations reveal the long-range nature of exchange interactions between Mn-Mn and Mn-Fe atoms. Moreover, the presence of the strong dependence of these interactions on the local environment, the magnetic frustration, and the effect of spin-orbit coupling lead to the possibility of realizing complex noncollinear magnetic structures such as helical spin spiral and half-skyrmion. Finally, we also investigated FexCo1-x nanowires deposited on Pt(111) surface aiming to investigate materials with large local magnetic moment. Our results reveal that the Fe and Co spin magnetic moment are independent of the Fe concentration with the enhancement of the spin magnetic moment when compared with the FeCo bcc alloys, while the average spin magnetic moment is a linear function of the Fe concentration. This is in contrast to the Slater-Pauling model observed in the FeCo bcc alloys. The average orbital magnetic moment shows a linearly decreasing behavior with the Fe concentration which is in contrast to the behavior of FexCo1-x monolayer on Pt(111) surface.
3

Lyderystės fenomenas Meilės Lukšienės veikloje / Phenomenon of leadership in activities of Meilė Lukšienė

Pusčienė, Jolanta 05 August 2013 (has links)
Darbe atskleidžiamas M. Lukšienės lyderystės fenomenas švietimo reformos laikotarpiu. Tyrėjams intriga: kokios aplinkybės kokius asmenis iškelia į lyderius, kaip susiklosto tokia lyderystė ir kokia ji yra šiuo konkrečiu – M. Lukšienės atveju. Mokslinės literatūros analizės, rašytinių dokumentinių šaltinių kokybinė analizės, ekspertų apklausos metodo, teorinių prielaidų ir tyrimų duomenų lyginamosios analizės pagrindu daromos išvados apie lyderystės fenumenalumą M. Lukšienės veikloje. / The project reveals phenomenon of leadership activities of M. Lukšienė during education reform in Lithuania. The researches face the issues: What circumstances do make the leaders rise? How such leadership develop? And what style of leadership is in case of M. Lukšienė? based on analysis of scientific literature; qualitative analysis of written document sources; method of expert survey; comparative analysis of theoretical prerequisites and research data were made conclusions about phenomenon of leadership in activities of Meilė Lukšienė.
4

Barn enligt barn : Barn som fenomen, undersökande av dess väsen och essens.

Andersson, Evelina January 2017 (has links)
Abstract  Children according to children  From a phenomenological perspective of childhood sociological approach I have had interviews with eight children made a qualitative survey. The purpose of which was to seek knowledge about children's views on children, and to explore the essence of the phenomenon of children. What emerges from the interviews is that there is a clear differentiation between children and adults. Children and adults do not according to children do the same things, and it is the size acording to them to see if it is a child or not.  Being a child is a temporary state, but for the children is the beginning and the end difficult to define. Age has a part in it but also how children play.  Based on my interviews I see children describe children as playing thinking phenomena when they analyze children from an outside perspective. / Sammanfattning  Barn enligt barn  Utifrån ett fenomenologiskt perspektiv med barndomssociologiskt synsätt har jag genom intervjuer med åtta barn gjort en kvalitativ undersökning, där syftet varit att söka kunskap om barns syn på barn, samt att utforska essensen i fenomenet barn.  Det som framkommer i intervjuerna är att det finns en tydlig differentiering mellan barn och vuxna. Barn och vuxna gör, enligt barn, inte samma saker och det går på storleken att se om det är ett barn eller ej. Att vara barn är ett temporärt tillstånd men för barnen är början och slutet svåra att definiera. Åldern har med saken att göra men också leken.  Utifrån mina intervjuer ser jag barnen beskriva barnen som lekande tänkande fenomen där de i stort intar en utifrån-position i sina svar på de frågor jag ställer.
5

Vliv hradních zřícenin na diverzitu vegetace v krajině / Effect of castle ruins on diversity of vegetation in the landscape

Javorský, Tomáš January 2013 (has links)
Medieval castle ruins undoubtedly create the face of the Czech landscape. Moreover, the few previous studies on this topic have shown that ruins are unique and extraordinary biotope. This work aims to characterize castle vegetation on thirty examined localities (thirty ruins). Phytosociological relevés and soil samples were collected, soil depth was measured and the cover of individual layers was observed - all of this on three spots on each locality. One of the places covered castle and the other ones the nearby forests (each one was chosen differently than the other). The castle walls were sampled separately. The results show that castles not only increase the diversity of forests by hosting a higher number of species but also by a different species composition - castles have a rather large set of species with high fidelity to ruins areas. Approximately half of the uniqueness of the ruins can be explained by the soil qualities, such as higher pH, higher quantity of calcium and magnesium, the other half remains unclear notwithstanding the usage of various explanatory variables. It is certain that castle ruins are from a biological point of view exceptional, unique and they surely deserve the attention which we owe them so far.
6

Fenomenologi- En litteraturstudie av fenomenologin som presenterades på kandidatprogrammet Socialpsykiatri på Malmö Universitet. / Phenomenology- A literature study of phenomenology that was presented on the bachelor's program of Social Psychiatry at Malmö University

Mohammad, Besma, hakaj, Noar January 2020 (has links)
Fenomenologin har sin grund inom filosofin och intresserar sig för att studera upplevelser och upplevelsen av personens mening, hur personen upplevde en viss händelse och vad personen upplevde. Syftet med den här studien är att studera den versionen av fenomenologi som beskrivs i kurslitteraturen som användes på kandidatprogrammet Socialpsykiatri på Malmö Universitet. Studien är en kvalitativ litteraturstudie. Fenomenologerna är intresserade av att gå tillbaka till själva upplevelsen och studera individens livs erfarenheter av respektive fenomen. Fenomenologin vill studera fenomen och upplevelser för att få ett holistiskt perspektiv av individen. Vid arbete med psykisk ohälsa vill fenomenologerna att den professionella ska ta hänsyn till personens egna livserfarenheter. / Phenomenology is based on philosophy and is interested in studying experiences and the experiences of the person´s meaning, how the person experienced a certain event and what the person experienced. The purpose of this study is to study the version of phenomenology described in the course literature used in the bachelor's program Social Psychiatry at Malmö University. The study is a qualitative literature study. The phenomenologists are interested in going back to the experience itself and studying the individual's life experiences of each phenomenon. Phenomenology wants to study phenomena and experiences in order to get a holistic perspective of the individual. When working with mental illness, the phenomenologists want the professional to take the person's own life experiences into account.
7

Langzeitversuche zur Latenz von Xanthomonas campestris pv. pelargonii und Vergleich mikrobiologischer, serologischer und molekulargenetischer Nachweisverfahren / Long-term studies on latency of Xanthomonas campestris pv. pelargonii and comparison of microbiological, serological and molecular genetic detection methods

Batur-Michaelis, Hacer 17 July 2003 (has links)
No description available.

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