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Spegeldämpande filter för L-bandIvarsson, Tommy January 2007 (has links)
<p>I detta examensarbete presenteras två olika konstruktionslösningar för ett spegeldämpande filter till en heterodynmottagare för L-bandet. Båda filtren är uppbyggda av distribuerade element i mikrostripsteknik. Filtertyper som behandlas är combline med kapacitansdioder för avstämning samt filter med element av typen commensurate length transmissionsledning. Nödvändig teori om mikrostripteknik och distribuerade element behandlas. Konstruktionen av filtren beskrivs steg för steg från filterkrav till färdig mönsterlayout. Layouterna har simulerats med em™ simulatorprogram.</p>
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Spegeldämpande filter för L-bandIvarsson, Tommy January 2007 (has links)
I detta examensarbete presenteras två olika konstruktionslösningar för ett spegeldämpande filter till en heterodynmottagare för L-bandet. Båda filtren är uppbyggda av distribuerade element i mikrostripsteknik. Filtertyper som behandlas är combline med kapacitansdioder för avstämning samt filter med element av typen commensurate length transmissionsledning. Nödvändig teori om mikrostripteknik och distribuerade element behandlas. Konstruktionen av filtren beskrivs steg för steg från filterkrav till färdig mönsterlayout. Layouterna har simulerats med em™ simulatorprogram.
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Theoretical Investigations of Selected Heavy Elements and Metal-hydrogen Systems by Means of Electronic Structure CalculationsAndersson, Per January 2001 (has links)
<p>Using <i>ab initio</i> electronic structure calculations based on density functional theory the crystal, electronic and magnetic structures of selected materials have been investigated. The materials which are the subjects of these investigations can be divided into two groups. Parts of the investigations have concerned actinides and rare earths, heavy elements with an <i>f</i>-shell electronic configuration. Here the effects of delocalization on EuCo<sub>2</sub>P<sub>2</sub> have been studied as well as the effect of including relativistic interactions when calculating the properties of thorium. For EuCo<sub>2</sub>P<sub>2</sub> it was found that at a low pressure the valence state of Eu changes from divalent to trivalent with associated effects on the crystal structure and magnetic state.</p><p>The other group of materials investigated are the metal-hydrogen and metal- lithium systems. Both of these have an important technological application in the form of batteries. Here the emphasis of the investigations has been the fundamental understanding of the mechanism of hydrogenation, and a novel theory explaining the driving force behind hydrogenation is suggested. Vanadium hydride, VH<sub>x</sub>, has been examined in detail and the reason for the anomalous non-isotropic expansion is explained. A scheme to make vanadium magnetic is also proposed. </p><p>Finally a method based on electron-hole coupled Green's functions has been used to facilitate the comparison between calculated electronic structures and X-ray absorption spectra. In connection to this a novel theory of charge transfer in the X-ray absorption process applied to transition metal oxides and lithium intercalated transition metal oxides is presented.</p>
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Theoretical Investigations of Selected Heavy Elements and Metal-hydrogen Systems by Means of Electronic Structure CalculationsAndersson, Per January 2001 (has links)
Using ab initio electronic structure calculations based on density functional theory the crystal, electronic and magnetic structures of selected materials have been investigated. The materials which are the subjects of these investigations can be divided into two groups. Parts of the investigations have concerned actinides and rare earths, heavy elements with an f-shell electronic configuration. Here the effects of delocalization on EuCo2P2 have been studied as well as the effect of including relativistic interactions when calculating the properties of thorium. For EuCo2P2 it was found that at a low pressure the valence state of Eu changes from divalent to trivalent with associated effects on the crystal structure and magnetic state. The other group of materials investigated are the metal-hydrogen and metal- lithium systems. Both of these have an important technological application in the form of batteries. Here the emphasis of the investigations has been the fundamental understanding of the mechanism of hydrogenation, and a novel theory explaining the driving force behind hydrogenation is suggested. Vanadium hydride, VHx, has been examined in detail and the reason for the anomalous non-isotropic expansion is explained. A scheme to make vanadium magnetic is also proposed. Finally a method based on electron-hole coupled Green's functions has been used to facilitate the comparison between calculated electronic structures and X-ray absorption spectra. In connection to this a novel theory of charge transfer in the X-ray absorption process applied to transition metal oxides and lithium intercalated transition metal oxides is presented.
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The Concept of Commensurate with Income : Retroactive adjustments and the arm's length standardBorgström, Ingrid, Andersson, Stefan January 2009 (has links)
This master’s thesis deals with the transfer pricing of intangibles and focuses on the U.S. standard commensurate with income. This standard has been accused of being incompatible with the overriding principle of transfer pricing, the arm’s length standard, and is not endorsed by the OECD. Recent developments on the topic include the introduction of a similar provision in Germany. The purpose is to evaluate the standard’s compatibility with the arm’s length standard and to establish the current position of the concept of commensurate with income. To meet this purpose the thesis first describes the inherent problems surrounding transfer pricing of intangibles as well as provides a background to transfer pricing in the U.S. The focus then shifts towards the history, application and criticism of the commensurate with income standard. The thesis also gives an account of the OECD’s and Germany’s positions on the matter. In the final analysis the compatibility with the arm’s length standard is examined from two angles; the commensurate with income standard’s valuation approach on one hand and its use of hindsight on the other. The commensurate with income standard uses an income approach to valuation of transfers of intangibles instead of the market approach recommended by the OECD. This may lead to overvaluation of intangibles and is not strictly in line with the arm’s length standard. The German commensurate with income provision is more in line with the market approach and is therefore more compatible with the arm’s length standard in this aspect. The commensurate with income standard allows adjustments to transfer prices with the benefit of hindsight. The actual income from a transferred intangible is thus used as evidence as to whether or not the original transfer price was set reasonably. The OECD is of the opinion that only information known at the time of the transfer should be used, but makes an exception for the particular situation when a tax authority can prove that unrelated parties would have adjusted transfer prices retroactively. The point made here is that the commensurate with income standard places the burden of proof on the taxpayer, while the OECD places it on the tax authority. This allows the OECD to stay true to the arm’s length standard, while the U.S. and Germany deviates somewhat from it. However, there is no exact manner in which to define the arm’s length standard, and even the OECD deviates from it more or less. The commensurate with income standard may be one step further away from the purest definition of it but not a complete deviation. The German version of commensurate with income manages to target the same problem while staying closer to the arm’s length standard. Germany has thereby found a middle way and might hold the solution to finding a consensus between the OECD and the U.S.
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The Concept of Commensurate with Income : Retroactive adjustments and the arm's length standardBorgström, Ingrid, Andersson, Stefan January 2009 (has links)
<p>This master’s thesis deals with the transfer pricing of intangibles and focuses on the U.S. standard commensurate with income. This standard has been accused of being incompatible with the overriding principle of transfer pricing, the arm’s length standard, and is not endorsed by the OECD. Recent developments on the topic include the introduction of a similar provision in Germany. The purpose is to evaluate the standard’s compatibility with the arm’s length standard and to establish the current position of the concept of commensurate with income.</p><p>To meet this purpose the thesis first describes the inherent problems surrounding transfer pricing of intangibles as well as provides a background to transfer pricing in the U.S. The focus then shifts towards the history, application and criticism of the commensurate with income standard. The thesis also gives an account of the OECD’s and Germany’s positions on the matter. In the final analysis the compatibility with the arm’s length standard is examined from two angles; the commensurate with income standard’s valuation approach on one hand and its use of hindsight on the other.</p><p>The commensurate with income standard uses an income approach to valuation of transfers of intangibles instead of the market approach recommended by the OECD. This may lead to overvaluation of intangibles and is not strictly in line with the arm’s length standard. The German commensurate with income provision is more in line with the market approach and is therefore more compatible with the arm’s length standard in this aspect.</p><p>The commensurate with income standard allows adjustments to transfer prices with the benefit of hindsight. The actual income from a transferred intangible is thus used as evidence as to whether or not the original transfer price was set reasonably. The OECD is of the opinion that only information known at the time of the transfer should be used, but makes an exception for the particular situation when a tax authority can prove that unrelated parties would have adjusted transfer prices retroactively. The point made here is that the commensurate with income standard places the burden of proof on the taxpayer, while the OECD places it on the tax authority. This allows the OECD to stay true to the arm’s length standard, while the U.S. and Germany deviates somewhat from it.</p><p>However, there is no exact manner in which to define the arm’s length standard, and even the OECD deviates from it more or less. The commensurate with income standard may be one step further away from the purest definition of it but not a complete deviation. The German version of commensurate with income manages to target the same problem while staying closer to the arm’s length standard. Germany has thereby found a middle way and might hold the solution to finding a consensus between the OECD and the U.S.</p>
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Multiple Calibrations in Integrative Data Analysis: A Simulation Study and Application to Multidimensional Family TherapyHall, Kristin Wynn 01 January 2013 (has links)
A recent advancement in statistical methodology, Integrative Data Analyses (IDA Curran & Hussong, 2009) has led researchers to employ a calibration technique as to not violate an independence assumption. This technique uses a randomly selected, simplified correlational structured subset, or calibration, of a whole data set in a preliminary stage of analysis. However, a single calibration estimator suffers from instability, low precision and loss of power. To overcome this limitation, a multiple calibration (MC; Greenbaum et al., 2013; Wang et al., 2013) approach has been developed to produce better estimators, while still removing a level of dependency in the data as to not violate independence assumption. The MC method is conceptually similar to multiple imputation (MI; Rubin, 1987; Schafer, 1997), so MI estimators were borrowed for comparison.
A simulation study was conducted to compare the MC and MI estimators, as well as to evaluate the performance of the operating characteristics of the methods in a cross classified data characteristic design. The estimators were tested in the context of assessing change over time in a longitudinal data set. Multiple calibrations consisting of a single measurement occasion per subject were drawn from a repeated measures data set, analyzed separately, and then combined by the rules set forth by each method to produce the final results. The data characteristics investigated were effect size, sample size, and the number of repeated measures per subject. Additionally, a real data application of an MC approach in an IDA framework was conducted on data from three completed, randomized controlled trials studying the treatment effects of Multidimensional Family Therapy (MDFT; Liddle et al., 2002) on substance use trajectories for adolescents at a one year follow-up.
The simulation study provided empirical evidence of how the MC method preforms, as well as how it compares to the MI method in a total of 27 hypothetical scenarios. There were strong asymptotic tendencies observed for the bias, standard error, mean square error and relative efficiency of an MC estimator to approach the whole set estimators as the number of calibrations approached 100. The MI combination rules proved not appropriate to borrow for the MC case because the standard error formulas were too conservative and performance with respect to power was not robust. As a general suggestion, 5 calibrations are sufficient to produce an estimator with about half the bias of a single calibration estimator and at least some indication of significance, while 20 calibrations are ideal. After 20 calibrations, the contribution of an additional calibration to the combined estimator greatly diminished.
The MDFT application demonstrated a successful implementation of 5 calibration approach in an IDA on real data, as well as the risk of missing treatment effects when analysis is limited to a single calibration's results. Additionally, results from the application provided evidence that MDFT interventions reduced the trajectories of substance use involvement at a 1-year follow-up to a greater extent than any of the active control treatment groups, overall and across all gender and ethnicity subgroups. This paper will aid researchers interested in employing a MC approach in an IDA framework or whenever a level of dependency in a data set needs to be removed for an independence assumption to hold.
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Investigations into the interfacial interaction of graphene with hexagonal boron nitrideWoods, Colin January 2016 (has links)
This thesis, submitted to the University of Manchester, covers a range of topics related to current research in two-dimensional materials under the title: 'Investigations into the interfacial interaction of graphene with hexagonal boron nitride.'In the last decade, two-dimensional materials have become a rich source of original research and potential applications. The main advantage lies in the ability to produce novel composite structures, so-called 'layered heterostructures', which are only a few atomic layers thick. One can utilise the unique properties of several species of crystal separately, or how they interact to realise a diverse range of uses. Two such crystals are graphene and hexagonal boron nitride. Hexagonal boron nitride has, so far, been used primarily as a substrate for graphene, allowing researchers to get the most out of graphene's impressive individual properties. However, in this thesis, the non-trivial van der Waals interaction between graphene and hexagonal boron nitride is examined. The interface potential reveals itself as a relatively large-scale, orientation-dependant superlattice, which is described in chapters 1 and 2.I In Chapter 4, the effect of this superlattice is examined by measurement of its effect upon the electrons in graphene, where its modulation leads to the creation of second and third generation Dirac points, revealing Hofstadter's Butterfly. As well as an excellent example of the physics possible with graphene, it also presents a new tool with which to create novel devices possessing tailored electronic properties. II In chapter 5, the consequential effect of the superlattice potential on the structure of graphene is studied. Results are discussed within the framework of the Frenkel-Kontorova model for a chain of atoms on a static background potential. Results are consistent with relaxation of the graphene structure leading to the formation of a commensurate ground state. This has exciting consequences for the production of heterostructures by demonstrating that alignment angle can have large effects upon the physical properties of the crystals. III In chapter 6, the van der Waals potential is shown to be responsible for the self-alignment of the two crystals. This effect is important for the fabrication of perfectly aligned devices and may lead to new applications based on nanoscale motion.
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Contrôle de la microstructure et des propriétés de transport d'alliages incommensurables de siliciure de manganèse pour la thermoélectricité / Microstructure control and transport properties of incommensurate manganese silicide based alloys for thermoelectricityVives, Solange 12 November 2015 (has links)
Valoriser l'énergie perdue sous forme de chaleur par les moteurs thermiques en électricité via desgénérateurs thermoélectriques permettrai de diminuer l'empreinte carbone des transports routiers. Unesélection des matériaux basée sur des critères de performance, de coût et de développement durable aconduit au choix du siliciure de manganèse MnSi (semi-conducteur de type p). En s'appuyant sur uneapproche couplant la métallurgie et la chimie du solide, ce travail revisite l'état de l'art sur ces alliageset révèle les relations entre la structure (inco/commensurabilité), la microstructure et le procédé. Unemeilleure compréhension de ces liens a permis d'acquérir un contrôle plus précis des microstructures,et par conséquent d'optimiser les propriétés thermoélectriques, et a conduit à la mise au point d'unenouvelle voie de synthèse pour MnSi. De plus, la production de matériaux purs et texturés a permisde mettre en évidence l'isotropie des propriétés de transport de la phase MnSi. Enfin, cette étudesuggère une relation entre la texture des joints de grains et la ségrégation dans des alliages dopés,ouvrant de nouvelles perspectives pour améliorer les propriétés thermoélectriques. / Generating electricity from waste heat by means of thermoelectric generators may represent a very interestingopportunity to significantly reduce the impact of road transportation. In this context, HigherManganese Silicide (HMS) based alloys are studied as p-type semiconductors to achieve a sustainablescale-up of this technology. Through a strategy coupling metallurgy and solid state chemistry, thiswork revisits the knowledge on HMS and reveals the relationship between the phases, the microstructureand the manufacturing process. This systematic study has lead to the establishment of designguidance to maximize the performance and thus, to a new synthesis route. In addition, the productionof grain oriented and highly pure HMS materials evidences the isotropy of the transport properties ofHMS. Finally, this study suggests a relationship between grain boundary texture and segregation indoped-HMS, opening new directions for enhancing thermoelectric properties.
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