Future ambitious solar system exploration missions are likely to require ever larger propulsion capabilities and involve innovative interplanetary trajectories in order to accommodate the increasingly complex mission scenarios. Two recent advances in trajectory design can be exploited to meet those new requirements: the use of low-thrust propulsion which enables larger cumulative momentum exchange relative to chemical propulsion; and the consideration of low-energy transfers relying on full multi-body dynamics. Yet the resulting optimal control problems are hypersensitive, time-consuming and extremely difficult to tackle with current optimization tools. Therefore, the goal of the thesis is to develop a methodology that facilitates and simplifies the solution finding process of low-thrust optimization problems in multi-body environments. Emphasis is placed on robust techniques to produce good solutions for a wide range of cases despite the strong nonlinearities of the problems. The complete trajectory is broken down into different component phases, which facilitates the modeling of the effects of multiple bodies and makes the process less sensitive to the initial guess. A unified optimization framework is created to solve the resulting multi-phase optimal control problems. Interfaces to state-of-the-art solvers SNOPT and IPOPT are included. In addition, a new, robust Hybrid Differential Dynamic Programming (HDDP) algorithm is developed. HDDP is based on differential dynamic programming, a proven robust second-order technique that relies on Bellman's Principle of Optimality and successive minimization of quadratic approximations. HDDP also incorporates nonlinear mathematical programming techniques to increase efficiency, and decouples the optimization from the dynamics using first- and second-order state transition matrices. Crucial to this optimization procedure is the generation of the sensitivities with respect to the variables of the system. In the context of trajectory optimization, these derivatives are often tedious and cumbersome to estimate analytically, especially when complex multi-body dynamics are considered. To produce a solution with minimal effort, an new approach is derived that computes automatically first- and high-order derivatives via multicomplex numbers. Another important aspect of the methodology is the representation of low-thrust trajectories by different dynamical models with varying degrees of fidelity. Emphasis is given on analytical expressions to speed up the optimization process. In particular, one novelty of the framework is the derivation and implementation of analytic expressions for motion subjected to Newtonian gravitation plus an additional constant inertial force. Example applications include low-thrust asteroid tour design, multiple flyby trajectories, and planetary inter-moon transfers. In the latter case, we generate good initial guesses using dynamical systems theory to exploit the chaotic nature of these multi-body systems. The developed optimization framework is then used to generate low-energy, inter-moon trajectories with multiple resonant gravity assists.

La microscopie de photoïonisation est une technique qui permet d'obtenir une image macroscopique de la fonction d'onde électronique habituellement confinée autour d'un atome. L'expérience consiste à photoïoniser près du seuil un atome en présence d'un champ électrique statique. Le traitement classique du mouvement d'un électron se déplaçant dans un champ coulombien en présence d'un champ électrique statique, montre qu'une multitude de trajectoires électroniques mènent à un point de l'espace classiquement accessible. Quantiquement, les ondes partielles associées à ces trajectoires interfèrent, et ce phénomène est directement mesurable au moyen d'un détecteur sensible en position. Cette thèse propose une étude classique, semi-classique et quantique de la microscopie de photoïonisation. L'originalité de ce travail est le développement de simulations par propagation de paquets d'ondes grâce un algorithme de type Split-Operator. Nous proposons une étude systématique de l'Hydrogène et montrons qu'il est possible d'observer à l'aide d'un microscope de photoïonisation, la fonction d'onde des états Stark résonants du continuum d'ionisation de l'Hydrogène. Enfin nous décrivons l'effet du cœur électronique sur la microscopie d'atomes non-hydrogénoïdes.

This examines the interplay of structure and local electrostatic fields in protein-protein and protein-solvent interactions. The partial charges of the protein amino acids and the polarization of the surrounding solvent create a complex system of electrostatic fields at protein-protein and protein-solvent interfaces. An approach incorporating vibrational Stark effect (VSE) spectroscopy, dissociation constant measurements, and molecular dynamics (MD) simulations was used to investigate the electrostatic interactions in these interfaces. Proteins p21Ras (Ras) and Rap1A (Rap) have nearly identical amino acid sequences and structures along the effector-binding region but bind with different affinities to Ral guanine nucleotide dissociation stimulator (RalGDS). A charge reversion mutation at position 31 alters the binding affinity of Ras and Rap with RalGDS from 0.1 [mu]M and 1 [mu]M, to 1 [mu]M and 0.5 [mu]M, respectively. A spectral probe was placed at various locations along the binding interface on the surface of RalGDS as it was docked with Ras and Rap single (position 30 or 31) and double mutants (both positions). By comparing the probes' absorption energies with the respective wild-type (WT) analogs, VSE spectroscopy was able to measure molecular-level electrostatic events across the protein-protein interface. MD simulations provided a basis for deconvoluting the structural and electrostatic changes observed by the probes. The mutation at position 31 was found to be responsible for both structural and electrostatic changes compared to the WT analogs. Furthermore, previous identification of positions N27 and N29 on RalGDS as "hot spots" that help discriminate between structurally similar GTPases was supported. The RalGDS probe-containing variants and three model compounds were placed in aqueous solvents with varying dielectric constants to measure changes in absorption energy. We investigated the ability of the Onsager solvent model to describe the solvent induced changes in absorption energy, while MD simulations were employed to determine the location and solvation of the probes at the protein-solvent interface. The solvent accessible-surface area, a measure of hydration, was determined to correlate well with the change in magnitude of the probe's absorption energy and the displaced solvent by the probe. / text

Theoretical investigation of the dynamics of adiabatic quantum mechanics in two different, highly polar systems has been made. The systems were chosen for their fundamental scientific interest, as they represent atoms and molecules with exaggerated properties, as well as ease of experimental study as such highly polar systems are easier to manipulate using readily-available electric fields. A model two-level system is used to derive one approach for maximizing the probability of adiabatic passage through an avoided crossing and this is compared with the classic Landau-Zener result, and the commonly encountered spin-flip problem of a particle with spin located in a rotating magnetic field. This approach is applied to the avoided crossing between the n = 13, n1 − n2 = 11 (dipole moment of 532 D) and the n = 14, n1 − n2 = −12 (dipole moment of -657 D) highly polar Stark states of the lithium atom at 447 kV/m. Ion-pair formation from two neutral lithium atoms, one in the 2s ground state and the other in an excited state, is also investigated. The cross section σ(v) for free ion-pairs is calculated for the initial colliding pairs of atomic states located below the ion-pair threshold. Li(2s) + Li(3d) is seen to possess the largest cross section (σ(v0) = 569.2 a.u.) at its threshold velocity. The implications of this for bound ion-pair, i.e. heavy Rydberg system, production are briefly discussed. Furthermore, experimental progress towards the production of these atomic and molecular systems from a beam of lithium is presented. / Thesis (Master, Physics, Engineering Physics and Astronomy) -- Queen's University, 2009-12-09 16:49:41.184

In this essay, I make a queer feminist analysis of four novels written by the Swedish author Sigge Stark. The novels are: Uggleboet, Manhatareklubben, Cirkus Demonio och Baskerflickan. Using Judith Butler's theories I examine the relations between sex/gender and sexuality in the four books and show how the construction of gender is performed and the heterosexual normativity is jeopardized. I also examine whether, and if so how, Sigge Stark uses the romantic and the gothic genres to include transcending gender identities and sexualities in her work. The essay also includes a contextualisation of her prerequisities as an author and the necessity in performing a critical analysis of mass produced romantic literature.

Cette thèse porte sur l'étude de l'émissivité et de l'opacité dans les plasmas de fusion inertielle (FCI), et des processus atomiques dans les plasmas de fusion magnétique (FCM).En FCI, nous avons étudié les spectres d'émissivité du hohlraum de l'approche indirecte et d'opacité des dopants de l'ablateur. Leur connaissance permet d'améliorer la compression de la cible de D-T et ainsi favoriser les réactions de fusion. Nous avons caractérisé les spectres lié-lié de l'or, du carbone et du germanium au moyen de méthodes détaillées (code PPP) mais qui s'avèrent coûteuses en temps de calculs et limitées quand le nombre de niveaux/ions augmente. Pour optimiser le temps de calcul sans perdre en précision, une méthode hybride détaillée/statistique (code SCO-RCG) a fait l'objet de comparaison/validation avec le code PPP sur des cas tests. Cette approche a ensuite été appliquée au calcul de l'opacité totale (lié-lié, lié-libre, libre-libre) pour tous les états d'ionisation du germanium et du silicium. Les spectres obtenus sont ensuite comparés dans une large gamme d'énergies en vue d'optimiser la compression de la cible.En FCM, à partir d'expériences effectuées sur les tokamaks Tore Supra (CEA Cadarache) et ASDEX Upgrade (Max Planck Institut, Garching), nous nous proposons de développer une nouvelle base de données de physique atomique (sections efficaces, taux des processus,...) à l'aide du code HULLAC pour analyser des coefficients de transport. Le but de cette étude est la sensibilité aux données atomiques de la reconstruction des coefficients de transport par le code ITC. Pour le cas de l'argon, les sections efficaces de quelques processus sont présentées et les coefficients de taux sont comparés à ceux provenant du consortium ADAS.

In dieser Arbeit wurden mit Hilfe von Transportmessungen – vor allem mit thermischem Transport bei sehr tiefen Temperaturen – intermetallische Seltenerdverbindungen untersucht. Diese Materialien sind oft durch starke elektronische Korrelationen gekennzeichnet, die zu neuartigen Eigenschaften führen. Um die Wechselwirkungen in den untersuchten Systemen zu beeinflussen, führten wir ein Magnetfeld als zusätzlichen Parameter ein. Damit untersuchten wir drei Fragestellungen. Im ersten Teil überprüften wir die Gültigkeit des Wiedemann-Franz-Gesetzes in YbRh2Si2. Dieses Material zeigt einen durch ein kleines Magnetfeld induzierten quantenkritischen Punkt, für dessen unkonventionelle Eigenschaften es noch keine allgemein etablierte mikroskopische Theorie gibt. Mit Hilfe des Wiedemann-Franz-Gesetzes haben wir untersucht, ob eine solche Theorie im Rahmen des Quasiteilchenbildes formuliert werden kann. Während wir eine Bestätigung für Magnetfelder abseits des quantenkritischen Punktes zeigen, ergibt unsere Analyse direkt am quantenkritischen Punkt eine Verletzung des Weidemann-Franz-Gesetzes. Dies hat weitreichende physikalische Folgen, da eine Verletzung den Zusammenbruch des Konzeptes von Quasiteilchen impliziert. In der zweiten Studie untersuchten wir die Kondogittersysteme YbRh2Si2 und CeRu2Si2 in Magnetfeldern mit Energien von der Größenordnung der Kondotemperatur. Beide Systeme zeigen bislang ungeklärte feldinduzierte Übergänge mit sehr unterschiedlichen Signaturen jedoch den selben Vorschlägen für deren Ursache: ein abrupter Zusammenbruch des Kondoeffekts oder ein Lifshitzübergang. Mit Thermokraft- und Widerstandsmessungen konnten wir für CeRu2Si2 zeigen, dass auch der thermische Transport kompatibel mit einem Lifshitzübergang ist. Ein globales Modell, das thermodynamische Größen mit einschließt, ist jedoch weiterhin nicht vorhanden. In YbRh2Si2 detektierten wir anstatt eines einzelnen, insgesamt drei Übergänge in höheren Magnetfeldern. Mithilfe einer sehr guten Übereinstimmung von renormalisierten Bandstrukturrechnungen mit unseren und früheren Experimenten, können wir die Entwicklung von YbRh2Si2 im Magnetfeld als Superposition von einer stetigen Unterdrückung des Kondoeffekts und drei Lifshitzübergängen beschreiben. Im dritten Projekt untersuchten wir den supraleitenden Ordnungsparameter von LaPt4Ge12. Während frühere Experimente auf konventionelle Supraleitung hindeuten, wird für das eng verwandte PrPt4Ge12 unkonventionelle und/oder Multiband-Supraleitung diskutiert. Resultate an der Substitutionsreihe LaxPr1-xPt4Ge12 suggerieren jedoch kompatible Ordnungsparameter für beide Verbindungen. Unsere Ergebnisse der spezifischen Wärme und der temperatur- und feldabhängigen Wärmeleitfähigkeit an LaPt4Ge12 sind kompatibel mit dem Modell konventioneller Supraleitung ohne Nullstellen im der supraleitenden Bandlücke. Die Abhängigkeit der Wärmeleitfähigkeit vom Feldwinkel zeigt unerwartet umfangreiche Oszillationsmuster. Während solche Oszillationen oft als Zeichen von Nullstellen in der Bandlücke interpretiert werden, konnten wir die meisten Frequenzen anderen Ursachen zuordnen. Eine sehr genaue Analyse von winkelabhängigen Messungen ist daher unabdingbar, um daraus Schlussfolgerungen für den Ordnungsparameter ziehen zu können.

Det fria kriget är ett doktrinärt begrepp som beskriver hur svaga avskurna reguljära förband ska genomföra sin krigföring. Det finns ingen entydig teori som kan förklara vad som leder till framgång i denna form av krigföring då den teoretiskt ligger mellan forskningsområdena landkrigföring och små krig. Denna teoriutvecklande uppsats gör en ansats att från land- och gerillakrigföringsteorier utveckla en teori för att förklara framgångsfaktorer för det fria kriget. Teoriutvecklingen sker genom att en hypotes tas fram genom en hypotetisk-deduktiv metod. Hypotesen operationaliseras och prövas i en tvåfallstudie. Prövningen leder till en förfinad hypotes som kan anses vara en normativ teori som förklarar hur framgång i det fria kriget kan nås. Teorin för att förklara ett framgångsrikt förande av fria kriget: Genom att utsätta motståndaren för ett taktiskt dilemma med ett hot på djupet, kan tid skapas för den egna strategiska nivån genom motståndarens kraftsplittring eller kulmination. Indirekt metod används för att kompensera för asymmetrin i styrkeförhållanden. Genom att slå mot identifierade svaga delar och kommunikationer skapas möjligheter till att nå lokal överlägsenhet. Dessa svaga delar påverkar motståndarens förmåga till krigföring och därmed kan tid skapas på den strategiska nivån. Terrängens möjlighet för att ge skydd och uthållighet samt dess förutsättningar för den svage att kompensera asymmetrin är avgörande för det avskurna förbandets uthållighet. Genom att anpassa förbandet och styra med uppdragstaktik kan sannolikt leda till framgång i det fria kriget. Denna teori ger en förklaring till framgång men behöver ytterligare prövning då delar av förklaringen kan ligga i för uppsatsen avgränsade områden.

Functional heterojunctions in organic electronic devices are interfaces formed either between a conducting electrode and an organic semiconductor or between two different organic semiconductors in blended and multilayered structures. This thesis is primarily concerned with the energy level alignment and the interfacial electronic structures at functional heterojunctions encountered in electronic devices made with solution-processable semiconducting polymers. Investigations on the electronic structures across these heterointerfaces are performed with the combined use of electromodulation and photoemission spectroscopic techniques. Electromodulation and ultraviolet photoemission spectroscopic techniques enable direct determination of the surface work functions of electrodes at the electrode/semiconducting polymer interfaces. We overcame the inherent problems faced by electromodulation spectroscopy, which undermine accurate determination of interfacial electronic structures, by performing electroabsorption (EA) measurements at reduced temperatures. We showed in this thesis that low-temperature EA spectroscopy is a surface sensitive technique that can determine the interface electronic structures in electrode/polymer semiconductor/electrode diodes. Using this technique, we demonstrated that the energy level alignments in these solution-processed organic electronic devices are determined by the surface work functions of passivated metals rather than by those of clean metals encountered in ultrahigh vacuum. This thesis also discloses our studies on the electronic structures in polymeric diodes with type II donor-acceptor heterojunctions using the EA spectroscopy. We showed that minimising meausurement temperature and attenuating EA illumination intensity enable accurate determinations of the electronic structures in these devices. We demonstrated that the electronic structures and the performance characteristics of multilayered polymer light-emitting diodes are also determined by the surface work functions of passivated metals. Our investigations confirm that electronic doping of the organic active layers, rather than minimisation of the Schottky barriers at electrode/polymer contacts, holds the key in realising high-performance organic light-emitting devices.

In this thesis we analyze lumpability of infinite dimensional dynamical systems. Lumping is a method to project a dynamics by a linear reduction operator onto a smaller state space on which a self-contained dynamical description exists. We consider a well-posed dynamical system defined on a Banach space X and generated by an operator F, together with a linear and bounded map M : X → Y, where Y is another Banach space. The operator M is surjective but not an isomorphism and it represents a reduction of the state space. We investigate whether the variable y = M x also satisfies a well-posed and self-contained dynamics on Y . We work in the context of strongly continuous semigroup theory. We first discuss lumpability of linear systems in Banach spaces. We give conditions for a reduced operator to exist on Y and to describe the evolution of the new variable y . We also study lumpability of nonlinear evolution equations, focusing on dissipative operators, for which some interesting results exist, concerning the existence and uniqueness of solutions, both in the classical sense of smooth solutions and in the weaker sense of strong solutions. We also investigate the regularity properties inherited by the reduced operator from the original operator F . Finally, we describe a particular kind of lumping in the context of C*-algebras. This lumping represents a different interpretation of a restriction operator. We apply this lumping to Feller semigroups, which are important because they can be associated in a unique way to Markov processes. We show that the fundamental properties of Feller semigroups are preserved by this lumping. Using these ideas, we give a short proof of the classical Tietze extension theorem based on C*-algebras and Gelfand theory.