Orientador: Carlos A. dos Reis Filho / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-07-25T01:29:03Z (GMT). No. of bitstreams: 1 JimenezGrados_HugoRicardo_M.pdf: 6853818 bytes, checksum: 62615fbbddc4edfbbb2597b948dd2738 (MD5) Previous issue date: 1999 / Resumo: : Este trabalho visa a familiarização com o dispositivo MOS- Split Drain através da construção de diferentes configurações geométricas, seguindo as regras da tecnologia CMOS - 0,8 Jl1Tlda AMS (Austria Mikrosysteme International), e de suas respectivas caracterizações elétricas e magnéticas. Medidas realizadas com os diversos protótipos fabricados permitiram a constatação de diversas características divulgadas na literatura e de suas limitações. O aprendizado que resulta deste trabalho é fundamental para o projeto que os pesquisadores do LPM2 - FEEC - UNICAMP ora realizam visando o desenvolvimento de um microsistema para a medição de consumo de energia elétrica / Abstract: This work aims at the familiarization with MOS- Split Drain transistors by constructing and measuring several units of different geometrical configurations, following the AMS (Austria Mikrosysteme International) design roles for CMOS 0.8 mm technology, and by characterizing the electrical and magnetic aspects of this device. Different prototypes were fabricated and measured, which allowed verifying either the validity or discrepancy of some of its properties published in the literature. The learning from this work is fundamental for the project, which is being carried on by researchers from LPM2 -FEEC - UNICAMP that are involved with the development of a novel microsystem for the measurement of electrical energy consumption / Mestrado / Mestre em Engenharia Elétrica

Orientador: Amir O. Caldeira / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-07-25T03:36:36Z (GMT). No. of bitstreams: 1 VillaresFerrer_Armando_D.pdf: 934070 bytes, checksum: a7809b615e4fae17323e7df32f980c69 (MD5) Previous issue date: 1999 / Resumo: O objetivo principal deste trabalho é o estudo da dinâmica das excitações topológicas em sistemas magnéticos de baixa dimensionalidade e pode ser dividido essencialmente em duas partes: fundamentos e aplicações. Nos fundamentos apresentamos os conceitos básicos sobre os sólitons em uma e duas dimensões e a forma em que é possível calcular este tipo de solução. Os casos particulares da equação de sine-Gordon (1D) e do modelo sigma não linear (2D) são discutidos em detalhe. Demostraremos que, ao contrário do que acontece do ponto de vista clássico, numa teoria quântica o centro do sóliton se acopla com as flutuações do campo em torno da solução solitônica levando a uma equação de movimento dissipativa. Para construir uma teoria quântica dos sólitons foi utilizado o método das coordenadas coletivas. Este método permitiu tratar corretamente os modos de freqüência zero que surgem em teorias invariantes por translação e ao mesmo tempo deduzir uma hamiltoniana quântica geral para o sistema interagente sóliton- flutuações em uma e duas dimensões. Posteriormente, partindo de uma hamiltoniana geral em 2D de interação sóliton- flutuações e usando o formalismo de Feynman e Vernon, é demostrado que o movimento das excitações topológicas nestes sistemas é do tipo Browniano e pode ser caracterizado por uma constante de decaimento que depende da temperatura. Uma expressão explícita para esta constante que define a mobilidade dos sólitons em duas dimensões foi também calculada. Os resultados obtidos tanto na quantização como na dinâmica dos sólitons foram posteriormente aplicados na descrição das excitações topológicas dos sistemas magnéticos de baixa dimensionalidade. Na primeira das aplicações apresentamos o estudo da dinâmica das paredes de Bloch que aparecem em um toy model para uma cadeia de spins ferromagnetica completamente anisotropica. Demostramos que neste sistema as paredes dos domínios magnéticos corresponedem aos sólitons de uma teoria de campos escalar efetiva em 1D que possui uma equação de movimento do tipo sine-Gordon. Utilizando a teoria geral desenvolvida previamente obtivemos uma hamiltoniana efetiva para o sistema que descreve o acoplamento entre as paredes dos domínios e as ondas de spin ( flutuações). Esta hamiltoniana permitiu a análise do movimento Browniano da parede em termos dos coeficientes de reflexão e transmisão do potencial efetivo que age sobre as ondas de spin criado pela presença da parede. Demostrou-se que para valores finitos do campo magnético externo aplicado no sistema a mobilidade da parede é também finita. O espectro do potencial para campos magnéticos fortes foi calculado e isto permitiu computar o valor da constante de decaimento da parede para qualquer valor da temperatura. Como resultado final apresentamos a dependência da mobilidade da parede com a temperatura e com o campo magnético aplicado. A segunda aplicação da teoria desenvolvida para a dinâmica dos sólitons corresponde ao estudo dos skyrmions. Como é demonstrado, os skyrmions são as excitações carregadas de mais baixa energia que aparecem no sistema de Hall em torno de u = 1 e podem ser detectados usando a técnica de ressonância nuclear magnética. Do ponto de vista teórico, partindo da densidade de lagrangiana proposta para a dinâmica dos spins no sistema de Hall, descreveremos os skyrmions pelas soluções do modelo sigma não linear com um tamanho fixo. Como se demostra, este tamanho está determinado pela competição dos termos de Zeeman e Coulomb no sistema. Usando então esta solução solitônica para descrever os skyrmions, calculamos uma hamiltoniana de interação skyrmion-mágnon via método das coordenadas coletivas. Posteriormente usando o formalismo desenvolvido estudamos a mobilidade dos skyrmions no sistema skyrmion-mágnon do gás bidimensional de elétrons. A dependência do coeficiente de transporte que caracteriza a dinâmica de um skyrmion com a temperatura e com o campo magnético foi calculada. Finalmente, a influência do caráter dissipativo domovimento dos skyrmions nas experiências de espalhamento de neutrons foi investigada / Abstract: We have studied the problem of the dissipative motion of Bloch walls considering a totally anisotropic one dimensional spin chain in the presence of a magnetic field. Using the so-called " collective coordinate method " we construct an effective Hamiltonian for the Bloch wall coupled to the magnetic excitations of the system. It allows us to analyze the Brownian motion of the wall in terms of the reflection coefficient of the effective potential felt by the excitations due to the existence of the wall. We find that for finite values of the external field the wall mobility is also finite. The spectrum of the potential at large fields is investigated and the dependence of the damping constant on temperature is evaluated. As a result we find the temperature and magnetic field dependence of the wall mobility. On the other hand, exploring a classical solution of the non-linear sigma model for a quantum Hall ferromagnet, a skyrmion-magnon effective hamiltonian is obtained via the collective coordinates method. Using the Feynman-Vernon functional integral formalism we investigate in a general way the dynamics of the 2-D solitons. Our treatment is applyed to the skyrmion-magnon model for the 2-D electron gas. The temperature dependent transport coefficients which characterize a single skyrmion dynamics is found. Finally an investigation on the possible in uence of the skyrmion dynamics in neutron scattering experiments is presented. / Doutorado / Física / Doutor em Ciências

Vissa ser förskolans hall som en passage mellan inne och ute. Andra ser förskolans hall som en miljö att utvecklas i. Medan vissa ser hallen som en stressig rutinsituation som endast är en övergång till något annat. I denna studie utgår vi ifrån att hallen är en plats för lärande. Syftet med denna fallstudie är att undersöka vilka läroplansmål som stöds vid rutinsituationer i förskolans hall. Vi vill studera om barn upplever något lärande i rutinsituationer och i så fall vad för lärande. Vi frågar oss Hur upplever barn förskolans hall som lärandemiljö? samt Vilka av läroplanens mål berörs i förskolans hall? För att undersöka detta har vi valt att använda oss av intervjuer och observationer som metod. Studien utgår från det sociokulturella perspektivet som innebär att utveckling och lärande sker när människor samspelar. Studien gjordes endast på en förskola och resultatet kan därför inte appliceras på svenska förskolor generellt. Studiens intervjuer visade att flertalet barn var överens om att det i hallen går att lära sig klä av och på sig. Resultatet av studiens observationer visade att det kunde ske många olika former av lärandetillfällen utifrån läroplanens mål i förskolans hall. De ämnen som berördes var bland annat matematik, naturvetenskap, språk och motorik.

Los sistemas de suspensión magnética vienen usándose actualmente en aplicaciones diversas como trenes de alta velocidad; rodamientos para ejes de alta velocidad; motores lineales; entre otras aplicaciones que se encuentran en sistemas de transporte, equipos médicos, motores usados en ambientes limpios (clean-rooms), etc. Estos sistemas pueden ser del tipo atractivo o repulsivo. El primero ha sido desarrollado principalmente en Alemania, mientras que el segundo se ha desarrollado en Japón. En la presente tesis se ha desarrollado el sistema del tipo atractivo que es inherentemente inestable y que requiere de acción de control a fin de suspender una masa (esfera) en el aire a cierta distancia de un electroimán (solenoide).

This thesis examines domestic service practises among some members of the Yorkshire gentry during the nineteenth century. Historians usually consider the gentry to have shared the same social outlooks and practises as other members of the upper class in spite of significant differences in income and political power. However, as they were less well-to-do, they could not afford to maintain the variety of servants a wealthy aristocrat could. Three main families were selected to reflect the range of incomes and possession or lack thereof of a hereditary title: the Listers of Shibden Hall, the Sykes of Sledmere House and the Pennymans of Ormesby Hall. The Yorkshire gentry organised country houses servants along the same hierarchical lines as prescriptive authors suggested because this gave servants clear paths for promotion which reduced the frequency of staff turnover; furthermore the architecture of their country houses promoted such organization. Secondly, this architecture reinforced the domestic social positions of every rung of the domestic hierarchy. As part of a unique subgroup of the upper class, gentry ladies were less likely to experience class conflict with servants clearly placed within the domestic service hierarchy. The conclusion is that through selective recruitment processes, the distinctive work environment and a particular labour pool, this group created a unique labour market tailored to their social and economic standing.

0 / SPK / specialcollections@tulane.edu

This Thesis project is going to be situated in my home town Östersund, 600 kilometers north from Stockholm.It´s a small town with 60 000 people and it is the only city of the region Jämtland in Norrland, Sweden.In the city centre of Östersund there is one existing bus terminal station where the buses arrive with people from the entire region.The task for this Thesis project is to rebuild the existing bus station in Östersund where the actual terminal building is going to be completely demolished and the entire block within the current bus stops is going to be rearranged.The topography of the terminal area is now dividing the regional buses that arrives on the upper level from the city buses that stops at the lower level. Therefore the main challenge of the new proposal is how one would strengthen the junction between these two flows of people and how a new architecture could enable the encounter between the countryside and the urban city. / Detta examensprojekt kommer att vara belägen i min hemstad Östersund, 600 kilometer norr om Stockholm. Det är en liten stad med 60 000 personer och det är den enda staden i regionen Jämtland, Norrland. I centrum av Östersund finns en befintlig bussterminalen där bussarna anländer med folk från hela regionen. Uppgiften för detta projekt är att bygga om den befintliga busstationen i Östersund topografin på terminalområdet i dagsläget separerar de regionala bussarna som anländer på den övre nivån från stadsbussarna som stannar på en lägre nivå. Den största utmaningen i det nya förslaget är hur man istället skulle kunna stärka förbindelsen mellan dessa två flöden av människor och hur en ny arkitektur kan möjliggöra mötet mellan glesbyggd och den urbana staden.

Magnetoresistive effects are powerful tools for studying the intricate structure of solid state electronic systems, and have many applications in our current information technology. In particular, the electronic system reflects the crystal symmetry and the orbital structure of the atoms of a given solid, and thus is crucial to understanding magnetism, superconductivity and many other effects which are of key interest to current solid state research. Consequently, studies of the electrical transport properties of solid state matter allow to evaluate this imprint and in turn draw conclusions about the interactions within a material. In this thesis, we will exploit the capabilities of magnetotransport measurements to infer the properties of a multitude of magnetic systems. In turn, this allows us to push the understanding of transport phenomena in magnetic materials. The first part of this work is focused on the magnetoresistance observed in spin Hall active metals in contact with a magnetic insulator. In such bilayers, the interfacial spin accumulation caused by the spin Hall effect in the metal can interact with the magnetic insulator, giving rise to interesting magnetoresistive effects. In the framework of this thesis, bilayers with several magnetic insulators are studied, including antiferomagnets, ferrimagnets and paramagnets (disordered magnets). For the disordered magnetic insulators, we find that the established spin Hall magnetoresistance framework does not allow to consistently describe the observed transport response. Consequently, we propose an alternative explanation of the magnetoresistance in such heterostructures, using the Hanle magnetoresistance and assuming an interface which has a finite electrical conductivity. This alternative model can serve to generalize the theory of the spin Hall magnetoresistance, providing addition information on the microscopic picture for the loss of the transverse spin component. Additionally, by partly removing the magnetic insulator and studying the ensuing changes, we verify that magnons are crucial for the observation of a non-local magnetoresistance in bilayers of a magnetic insulator and a metal. Finally, the local and non-local spin Seebeck effect (i.e. the electric field generated by a thermally driven pure spin current) is investigated in bilayers of Cr2O3 and Pt where the occurrence of a spin superfluid ground state was reported. In our sample, however, the transport response is consistent with the antiferromagnetic spin Seebeck effect mediated by the small magnetic field induced magnetization also reported for other antiferromagnet/metal heterostructures. As such, we cannot verify the presence of a spin superfluid ground state in the system. In the second part of this thesis, the topological properties of the electronic system and the related changes of the magnetoelectric and magnetothermal transport response are investigated. To that end, we first demonstrate a novel measurement technique, the alternating thermal gradient technique, allowing to separate the relevant thermovoltages from spurious other voltages generated within the measurement setup. We employ this novel technique for measuring the topological Nernst effect in Mn 1.8 PtSn and show the possibility to combine the magnetoelectric and magnetothermal transport response to evaluate the presence of topological transport signatures without requiring magnetization measurements. Additionally, we show that the anomalous Nernst effect in the non-collinear antiferromagnet Mn3Sn is connected to the antiferromagnetic domain structure: Using spatially resolved measurements of the anomalous Nernst effect, direct access to the antiferromagnetic domain structure is demonstrated. Additionally, a thermally assisted domain writing scheme is implemented, allowing the preparation of Mn3Sn into a defined antiferromagnetic domain state.

The anomalous Hall effect (AHE) has been discovered for over a century, but its origin is still highly controversial theoretically and experimentally. In this study, we investigated the scattering effect on the AHE for both exploring the underlying physics and technical applications. We prepared Cox(MgO)100-x granular thin films with different Co volume fraction (34≤x≤100) and studied the interfacial scattering effect on the AHE. The STEM HAADF images confirmed the inhomogeneous granular structure of the samples. As x decreases from 100 to 34, the values of longitudinal resistivity (pxx) and anomalous Hall resistivity (pAHE) respectively increase by about four and three orders in magnitude. The linear scaling relation between the anomalous Hall coefficient (Rs) and the pxx measured at 5 K holds in both the as-prepared and annealed samples, which suggests a skew scattering dominated mechanism in Cox(MgO)100-x granular thin films. We prepared (Fe36/n/Au12/n)n, (Ni36/n/Au12/n)n and (Ta12/n/Fe36/n)n multilayers to study the interfacial scattering effect on the AHE. The multilayer structures were characterized by the XRR spectra and TEM images of cross-sections. For the three serials of multilayers, both the pxx and pAHE increase with n, which clearly shows interfacial scattering effect. The intrinsic contribution decreases with n increases in the three serials of samples, which may be due to the crystallinity decaying or the finite size effect. In the (Fe36/n/Au12/n)n samples, the side-jump contribution increases with nn, which suggests an interfacial scattering-enhanced side jump. In the (Ni36/n/Au12/n)n samples, the side-jump contribution decreases with n increases, which could be explained by the opposite sign of the interfacial scattering and grain boundary scattering contributed side jump. In the (Ta12/n/Fe36/n)n multilayers, the side-jump contribution changed from negative to positive, which is also because of the opposite sign of the interfacial scattering and grain boundary scattering contributed side jump. The interfacial scattering effect on the AHE is much more complicated than surface scattering in thin films or scattering by delta-impurities in bulk-like samples.

No description available.