A Mie-based code is developed for multilayer concentric spheres. The code is used in conjunction with a finite-element package to investigate the plasmonic and optical properties of micro- and nanostructures. For plasmonic nanostructures, gold-silica-gold multilayer nanoshells are computationally investigated. A plasmon hybridization theory is used to interpret the optical tunability. The interaction between the plasmon modes on the inner core and the outer shell results in dual resonances. The low-energy dipole mode is red-shifted by reducing the spacing ( i.e. , the intermediate silica layer) between the core and the shell. This extra tunability allows the plasmon resonance of a multilayer nanoshell to be tuned to the near-infrared region from a visible silica-gold nanoshell whose gold shell cannot be further reduced in thickness. For multilayer nanoshells with reduced geometrical symmetry ( i.e. , the inner core is offset from the center), modes of different orders interact. The mixed interaction introduces the dipolar (bright) characteristic into the higher-order (dark) modes and improves their coupling efficiency to the excitation light. The excitation of the dark modes attenuates and red-shifts the dipole mode and gives it higher-order characteristics. For non-plasmonic structures, simulations have demonstrated that multilayered structures can either reduce or enhance the scattering of light. By adding an anti-reflection layer to as microsphere made of a high-index material, the scattering force can be dramatically reduced. The reduced scattering allows optical trapping of high-index particles. Additionally, the improved trapping is not largely sensitive to the refractive index or the thickness of the coating. The technique has the practical potential to lower the requirement on the numerical aperture of the microscope objectives, making possible the integration of the imaging and optical trapping systems. While the anti-reflection coating reduces scattering, the photothermal bubble (PTB) generated by gold nanoparticles by and large enhances the scattering of light. Transient PTBs are generated by super-heating gold nanoparticles with short laser pulses. Mie-based simulations predict that the scattering of PTBs strongly depends on the transient environment immediately surrounding the nanoparticles. A scattering enhancement of two-to-four orders of magnitude from PBT is demonstrated from both calculations and experiments. Lastly, the near-field coupling between different plasmonie structures for surface-enhanced Raman scattering is investigated. A gold-coated silicon-germanium nanocone substrate has been fabricated and characterized. Finite-element simulations reveal that individual nanocones generate strong tip enhancement with axially polarized light ( i.e. , light polarized along the vertical axis of the nanocone) while the enhancement from transversely polarized light ( i.e. , light polarized in the plane of the substrate) is relatively weak. By simply filling the valleys between nanocones with plasmonic gold nanoparticles, the performance of the substrate is improved with in-plane excitation. Simulations reveal strong coupling between nanoparticles and adjacent nanocones with transverse exactions. An over one order-of-magnitude improvement has been experimentally observed.

Jetströmmar betyder mycket för meteorologer och fungerar som ett hjälpmedel för prognostisering av lågtryck. Kvadrantmodellen för jetströmsstråk beskriver hur det kan bildas lågtryck och konvergens vid marknivå på olika sidor om jetströmmen. Jetströmmar är också av betydelse för flygtrafiken, eftersom man kan spara tid och bränsle genom att flyga in i – eller genom att inte flyga in i – en jetström. Det är känt att jetströmmar ibland kan ge upphov till klarluftsturbulens (CAT), och studier har visat att turbulensen ofta är associerade med stabilt stratifierade zoner i närheten av jetströmmen. Denna studie börjar med en teoridel där jetströmmars uppkomst och kvadrantmodellen redogörs. Teoridelen fortsätter med en kort beskrivning av hur jetströmmar påverkar flygtrafiken och vad det finns för system som varnar för farliga fenomen som är kopplade till jetströmmarna. Det tas även upp att flygturbulensen som upplevs av flygplan inte nödvändigtvis orsakas av termisk eller mekanisk turbulens, utan även kan orsakas av stående vågor. I arbetets senare del görs en fallstudie på två jetströmmar som gav upphov till kraftig flygturbulens under januari månad 2011. Från sonderingsdata beräknades Scorer-parametern och Richardsons tal för att se om dessa värden kunde relateras till flygturbulensen. Resultatet visade att Richardsons tal aldrig föll under 0.25 och antyder därför att det inte fanns någon fullt utvecklad turbulens. Vågor i luften kan därför vara en förklaring till flygturbulensen. Resultatet visade också att Scorer-parametern antog lokala minima och hade tydligare relation till flygturbulensen än Richardsons tal vad gäller flygturbulensens position i höjdled. / Jet streams are useful as a tool for meteorologist to make forecasts of low pressure areas. The four quadrant model describing jet streaks reveals how lows and convergence could form over ground levels on different sides of a jet streak. Jet streams are also of great importance for the aviation industry, as one could save time and fuel by flying into – or by not flying into – a jet stream. It is known that the jet streams sometimes can induce Clear Air Turbulence (CAT), and studies have shown that the turbulence is often associated with stable stratified layers in the vicinity of the jet stream. This study starts with a theory section describing the cause of jet streams and the four quadrant model. The theory section continues with a description of why jet streams could be a hazard for airplanes, and also a description of existing reporting and warning systems that are used to prevent pilots from flying into dangerous phenomena. In this section, it is also emphasized that in-flight turbulence not necessarily is a result of thermal or mechanical turbulence, but could also be induced by standing waves in the atmosphere. The latter part of this report is a case study of two jet streaks that was the cause of severe in-flight turbulence in January 2011. The Scorer parameter and the Richardson number were computed using data from atmospheric soundings. The results show that the Richardson number never fell below 0.25, suggesting that there were no fully-developed turbulence. Waves in the air could therefore be an alternative explanation to the reported in-flight turbulence. The results also show that the Scorer parameter had local minima on the levels where the in-flight turbulence occurred. In contrast to this, the Richardson number had no apparent relation to the position of the reported turbulence.

Video based remote sensing techniques are well suited to collect spatially resolved wave images in the surf zone with breaking waves and dynamic bathymetric changes. An advanced video-based depth inversion method is developed to remotely survey bathymetry in the surf zone. The present method involves image processing of original wave image sequences, wave property estimation based on linear feature extraction from the processed image sequences, and is combined with a nonlinear depth inversion model. The original wave image sequences are processed through video image frame differencing and directional low-pass filtering schemes to remove wave-breaking-induced foam noise having high frequencies in the surf zone. The features of individual crest trajectories are extracted from the processed and rectified image sequences, i.e. processed image cross-shore timestacks, by tracking pixels of high intensity within an interrogation window of a Radon-transform-based line-detection algorithm. The wave celerity is computed using space-time information of the extracted trajectories of individual wave crests in the cross-shore timestack domain. The presented retrieval of nearshore bathymetry from video image sequences is based on a nonlinear depth inversion using the nonlinear shallow water wave theory. The nonlinear wave amplitude dispersion effects at the breaker points are determined by combining the nonlinear shallow water celerity equation with a wave breaker criterion, thereby computing water depths iteratively from the celerity measured from the video data. The water depths estimated at the breaker points present initial bathymetric anchor points. Bathymetric profiles in the surf zone are inverted by calculating wave heights dissipated after wave breaking with a wave dissipation model and wave heights shoaled before wave breaking with a wave shoaling model. The continuous wave amplitude dispersion effects are subtracted from the measured celerity profiles, resulting in nearshore bathymetric profiles. The nonlinear depth inversion derived bathymetric estimates from nearshore imagery match the measured values with a biased mean depth error of about +0.06m in the depth range of 0.1 to 3m. In addition, the wave height estimates by the depth inversion model are comparable to the in-situ measured wave heights with a biased mean wave height error of about +0.14m. The present depth inversion method based on optical remote-sensing supports coastal management, navigation, and amphibious operations.

From a theoretical standpoint, the accurate description of potential energy surfaces for bond breaking and the equilibrium structures of metal-ligand catalysts are distinctly similar problems. Near degeneracies of the bonding and anti-bonding orbitals for the case of bond breaking and of the partially-filled d-orbitals for the case of metal-ligand catalyst systems lead to strong non-dynamical correlation effects. Standard methods of electronic structure theory, as a consequence of the single-reference approximation, are incapable of accurately describing the electronic structure of these seemingly different theoretical problems. The work within highlights the application of multi-reference methods, methods capable of accurately treating these near-degeneracies, for describing the bond-breaking potentials in several small molecular systems and the equilibrium structures of metal-salen catalysts. The central theme of this work is the ability of small, compact reference functions for accurately describing the strong non-dynamical correlation effects in these systems.

Unter Benutzng von 90.4/fb Daten, die das BABAR-Experiment in den Jahren 1999 bis 2002 genommen hat, wurden die Zerfälle Ds*+ -> Ds+ pi0 und Ds*+ -> Ds+ gamma mit zwei verschiedenen Methoden rekonstruiert. Die Rekonstruktions-Effizienzen wurden mittels Signal-Monte Carlo-Ereignissen und D*0-Zerfällen ermittelt. Auf diese Weise wurde das Partialbreiten-Verhältnis Gamma(Ds*+ -> Ds+ pi0) / Gamma(Ds*+ -> Ds+ gamma) auf vier verschiedene Weisen gemessen. Zusätzlich wurde das Partialbreiten-Verhältnis Gamma(D*0 -> D0 pi0) / Gamma(D*0 -> D0 gamma) gemessen. / Using 90.4/fb of data taken at the BABAR experiment in the years 1999 to 2002, the decays Ds*+ -> Ds+ pi0 and Ds*+ -> Ds+ gamma have been reconstructed with two different methods. Signal Monte Carlo events as well as D*0 decays have been used to determine the reconstruction efficiencies. Thereby, the partial widths ratio Gamma(Ds*+ -> Ds+ pi0) / Gamma(Ds*+ -> Ds+ gamma) has been measured in four different ways. Additionally, the partial widths ratio Gamma(D*0 -> D0 pi0) / Gamma(D*0 -> D0 gamma) has been measured.

Die Wirkung von Seltenerd-Stoerelementen in Seltenerd-Seltenerd-Nickel-Borkarbid-Verbindungen, die im gleichen Temperaturbereich Supraleitung und magnetische Ordnung zeigen, wird in Hinblick auf die Unterdrueckung der Supraleitung untersucht. Sie aeussert sich in magnetischer Paarbrechung, ferngeordneten Magnetstrukturen und Unordnung. Die Verbindungen wurden entsprechend der an das Material gestellten Anforderungen mittels Lichtbogenschmelzen, Rascherstarrung oder durch Einkristallzucht hergestellt. Die Unterdrueckung der supraleitenden Uebergangstemperatur in diesen Mischreihen mit magnetischen und nichtmagnetischen Seltenerdionen wird durch den Einfluss des effektiven de Gennes-Faktors, der der Konzentration der magnetischen Seltenerdionen Rechnung traegt, des Kristallfeldes und der durch die unterschiedlichen Radien der Seltenerdionen verursachten Unordnung erklaert. Die Unordnung wird durch die Varianz der Ionenradien quantifiziert und ihre Auswirkung auf die supraleitende Uebergangstemperatur und das obere kritische Feld sowie dessen Kruemmung in der Naehe der Uebergangstemperatur beobachtet. Die Uebergagstemperatur von Yttrium-Seltenerd-Nickel-Borkabid-Verbindungen wird im Bereich schwacher Konzentration von magnetischer Seltenerdionen fuer alle magnetischen Seltenerdionen qualitativ erfasst. In antiferromagnetisch geordneten Seltenerd-Seltenerd-Nickel-Borkabid-Verbindungen wirken unmagnetische Verunreinigungen stark paarbrechend, wobei dieser Mechanismus durch die Unordnung verstaerkt wird. Durch Neutronenbeugungsexperimente wurden die magnetischen Strukturen der Seltenerd-Seltenerd-Nickel-Borkabid-Verbindungen nachgewiesen. Bei vollstaendig ausgebildeter antiferromagnetischer Ordnung verzerrt das Kristallgitter aufgrund magnetoelastischer Effekte. In Holmium-Seltenerd-Nickel-Borkabid-Verbindungen konnten die drei bekannten magnetischen Strukturen gefunden werden, wodurch die Korrelation zwischen dem reentrant-Verhalten und magnetischer Fernordnung nachgewiesen wurde. Im aeusseren Magnetfeld werden die Strukturen anhand eines bekannten Feld-Temperatur-Phasendiagramms erklaert, in dem die magnetischen Ueberstrukturen als Funktion von Feld und Temperatur aufgestellt wurden.

Linear induction motors are applied in equipments with different requirements set up to the controlled motion parameters. Investigation of motoring and breaking modes remains the relevant problem nowadays. The scientific novelty is based on analysis of non-symmetrical operation modes of linear induction motor at supplying it by a voltage source, developing a generalized model of motoring and breaking dynamic modes and analyzing influence of linear motor windings connection way and control parameters on dynamic breaking characteristics. The coordinate transformations of linear induction motors dynamic models, based on rotational motor with assumptions valid for low speed motor and multi-pole motor, are considered. Mathematical and computer models to investigate symmetrical dynamic modes of linear induction drives are presented. Generalized model to investigate non-symmetrical dynamics modes is elaborated. The results of simulation are presented by dependences on the main variables in the time domain, and dependences on both constructional and control parameters that give possibility to optimize constructional parameters of motors.

Linear induction motors are applied in equipments with different requirements set up to the controlled motion parameters. Investigation of motoring and breaking modes remains the relevant problem nowadays. The scientific novelty is based on analysis of non-symmetrical operation modes of linear induction motor at supplying it by a voltage source, developing a generalized model of motoring and breaking dynamic modes and analyzing influence of linear motor windings connection way and control parameters on dynamic breaking characteristics. The coordinate transformations of linear induction motors dynamic models, based on rotational motor with assumptions valid for low speed motor and multi-pole motor, are considered. Mathematical and computer models to investigate symmetrical dynamic modes of linear induction drives are presented. Generalized model to investigate non-symmetrical dynamics modes is elaborated. The results of simulation are presented by dependences on the main variables in the time domain, and dependences on both constructional and control parameters that give possibility to optimize constructional parameters of motors.

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Both the “crisis of masculinity” and “quality TV” have been popular discourses in academia in recent years. Many of these contemporary quality TV series feature male anti-heroes at the center of their narratives. This dissertation argues that the constructions of masculinity in series such as "Breaking Bad" and "The Walking Dead" are informed by the Western hero. Furthermore, the dissertation links this recourse to an arguably outmoded model of masculinity to recent crisis tendencies in the USA, most notably the recent economic downturn and the aftermath of September 11 2001. Moreover, the return of the Western hero can be understood as a process of remasculinization in light of the crisis of masculinity.