Dissertations / Theses on the topic 'Atomic'
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Lombardi, Pietro Ernesto. "Coherent manipulation of the internal state of an atomic gas : from atomic memories to atomic interferometers." Paris 6, 2012. http://www.theses.fr/2012PA066417.
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Ce travail de thèse est consacré à l'exploration de méthodes cohérentes pour la manipulation des états internes d'une nuage atomique. L'objectif final est de créer un schéma pour la réalisation d'une mémoire quantique capable de stocker l'état quantique d'une impulsion lumineuse dans une cohérence atomique. J'ai exploré deux différentes réalisations expérimentales, les deux basées sur la transparence induite électromagnétiquement dans un système à trois niveaux en configuration Lambda. La première réalisation est basée sur sous-niveaux Zeeman d'atomes de césium à température ambiante (réalisé dans le groupe de E. Giacobino au LKB, Paris) en s'appuyant sur la ligne D2. En présence d’élargissement Doppler l'effet EIT est fortement réduite en raison de la présence de transitions adjacentes. Nous avons développé un modèle théorique pour décrire la réponse optique du système, comprenant les contributions des transitions hors résonance. Nous avons ensuite vérifié expérimentalement le modèle et trouvé une méthode pour améliorer la transparence optique basée sur un de-pompage sélectif en vitesse. La deuxième réalisation est basée sur les états hyperfins de atomes de rubidium ultra-froids piégés dans une micro-piège magnétique (réalisé dans le groupe de F. S. Cataliotti au LENS, Firenze). Dans cette expérience, nous avons observé une forte réduction (près de 6 ordres de grandeur) de la vitesse de la lumière dans l'ensemble atomique, une étape fondamentale vers la réalisation de stockage d'information cohérente. Nous avons développé également une méthode pour mesurer la phase relative entre deux impulsions de lumière en utilisant l'interférométrie atomiqueThis thesis work is devoted to the exploration of coherent methods for the manipulation of atomic internal states. The final aim is to create a robust scheme for the realization of a quantum memory capable of storing the quantum state of a light pulse in an atomic coherence. I have explored two different experimental realizations, both based on electromagnetically induced transparency in a three level Lambda scheme. The first realization was based on Zeeman sub-levels of Cesium atoms in a room temperature cell (realized in the group of Elisabeth Giacobino at LKB, Paris). In this experiment we characterized a memory based on the D2 line of 133Cs. In the presence of Doppler broadening the EIT effect is strongly reduced due to the presence of adjacent transitions. We developed a model to describe the optical response of the complete system including off-resonant transitions. We then experimentally verified the model and found a method to enhance the transparency based on velocity selective optical pumping. The second realization was instead based on hyperfine states of ultracold Rubidium atoms held in a magnetic microtrap (realized in the group of F. S. Cataliotti at LENS, Firenze). In this experiment we observed a strong reduction (by almost 6 orders of magnitude) in the speed of light within the atomic sample, a promising step towards the realization of coherent information storage. We developed also a method to measure the relative phase of light pulses using atomic interferometry. These findings open an interesting alternative route for the detection of quantum coherence and non-classical states
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Grimble, Ralph Ashley. "Atomic force microscopy : atomic resolution imaging and force-distance spectroscopy." Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312277.
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Arora, Bindiya. "Modeling of atomic systems for atomic clocks and quantum information." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 159 p, 2009. http://proquest.umi.com/pqdweb?did=1654501311&sid=2&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Gajinov, Vladimir. "Atomic dataflow model." Doctoral thesis, Universitat Politècnica de Catalunya, 2014. http://hdl.handle.net/10803/284658.
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With the recent switch in the design of general purpose processors from frequency scaling of a single processor core towards increasing the number of processor cores, parallel programming became important not only for scientific programming but also for general purpose programming. This also stressed the importance of programmability of existing parallel programming models which were primarily designed for performance. It was soon recognized that new programming models are needed that will make parallel programming possible not only to experts, but to a general programming community.
Transactional Memory (TM) is an example which follows this premise. It improves dramatically over any previous synchronization mechanism in terms of programmability and composability, at the price of possibly reduced performance. The main source of performance degradation in Transactional Memory is the overhead of transactional execution. Our work on parallelizing Quake game engine is a clear example of this problem. We show that Software Transactional Memory is superior in terms of programmability compared to lock based programming, but that performance is hindered due to extreme amount of overhead introduced by transactional execution.
In the meantime, a significant research effort has been invested in overcoming this problem. Our approach is aimed towards improving the performance of transactional code by reducing transactional data conflicts. The idea is based on the organization of the code in which highly conflicting data is promoted to dataflow tokens that coordinate the execution of transactions.
The main contribution of this thesis is Atomic Dataflow model (ADF), a new task-based parallel programming model for C/C++ that integrates dataflow abstractions into the shared memory programming model. The ADF model provides language constructs that allow a programmer to delineate a program into a set of tasks and to explicitly define data dependencies for each task. The task dependency information is conveyed to the ADF runtime system that constructs a dataflow task graph that governs the execution of a program. Additionally, the ADF model allows tasks to share data. The key idea is that computation is triggered by dataflow between tasks but that, within a task, execution occurs by making atomic updates to common mutable state. To that end, the ADF model employs transactional memory, which guarantees atomicity of shared memory updates.
The second contribution of this thesis is DaSH - the first comprehensive benchmark suite for hybrid dataflow and shared memory programming models. DaSH features 11 benchmarks, each representing one of the Berkeley dwarfs that capture patterns of communication and computation common to a wide range of emerging applications. DaSH includes sequential and shared-memory implementations based on OpenMP and TBB to facilitate easy comparison between hybrid dataflow implementations and traditional shared memory implementations. We use DaSH not only to evaluate the ADF model, but to also compare it with other two hybrid dataflow models in order to identify the advantages and shortcomings of such models, and motivate further research on their characteristics.
Finally, we study applicability of hybrid dataflow models for parallelization of the game engine. We show that hybrid dataflow models decrease the complexity of the parallel game engine implementation by eliminating or restructuring the explicit synchronization that is necessary in shared memory implementations. The corresponding implementations also exhibit good scalability and better speedup than the shared memory parallel implementations, especially in the case of a highly congested game world that contains a large number of game objects. Ultimately, on an eight core machine we were able to obtain 4.72x speedup compared to the sequential baseline, and to improve 49% over the lock-based parallel implementation based on work-sharing.Con el reciente cambio en el diseño de los procesadores de propósito general pasando del aumento de frecuencia al incremento del número de núcleos, la programación paralela se ha convertido en importante no solo para la comunidad científica sino también para la programación en general. Este hecho ha enfatizado la importancia de la programabilidad de los modelos actuales de programación paralela, cuyo objetivo era el rendimiento. Pronto se observó la necesidad de nuevos modelos de programación, para hacer factible la programación paralela a toda la comunidad. Transactional Memory (TM) es un ejemplo de dicho objetivo. Supone una gran mejora sobre cualquier método anterior de sincronización en términos de programabilidad, con una posible reducción del rendimiento como coste. La razón principal de dicha degradación es el sobrecoste de la ejecución transaccional. Nuestro trabajo en la paralelización del motor del juego Quake es un claro ejemplo de este problema. Demostramos que Software Transactional Memory es superior en términos de programabilidad a los modelos de programación basados en locks, pero que el rendimiento es entorpecido por el sobrecoste introducido por TM. Mientras tanto, se ha invertido un importante esfuerzo de investigación para superar dicho problema. Nuestra solución se dirige hacia la mejora del rendimiento del código transaccional reduciendo los conflictos con la información contenida en las transacciones. La idea se basa en la organización del código en el cual la información conflictiva es promocionada a señales del flujo de datos que coordinan la ejecución de las transacciones. La contribución principal de esta tesis es Atomic Dataflow Model (ADF), un nuevo modelo de programación para C/C++ basado en tareas que integra abstracciones de flujo de datos en el modelo de programación de la memoria compartida. El modelo ADF provee construcciones del lenguaje que permiten al programador la definición del programa como un conjunto de tareas, además de la definición explícita de las dependencias de datos para cada tarea. La información de dependencia de la tarea se transmite al runtime de ADF, que construye un grafo de tareas que es el que controla la ejecución de un programa. Adicionalmente, el modelo ADF permite que las tareas compartan información. La idea principal es que la computación es activada por el flujo de datos entre tareas, pero que dentro de una tarea la ejecución ocurre haciendo actualizaciones atómicas a un estado común mutable. Para conseguir este fin, el modelo ADF utiliza TM, que garantiza la atomicidad en las modificaciones de la memoria compartida. La segunda contribución es DaSH, el primer conjunto de benchmarks para los modelos de programación de flujo de datos híbridos y los de memoria compartida. DaSH contiene 11 benchmarks, cada uno representativo de uno de los Berkeley dwarfs que captura patrones de comunicaciones y procesamiento comunes en un amplio rango de aplicaciones emergentes. DaSH incluye implementaciones secuenciales y de memoria compartida basadas en OpenMP y TBB que facilitan la comparación entre los modelos híbridos de flujo de datos e implementaciones de memoria compartida. Nosotros usamos DaSH no solo para evaluar ADF, sino también para compararlo con otros dos modelos híbridos para identificar sus ventajas. Finalmente, estudiamos la aplicabilidad de dichos modelos híbridos para la paralelización del motor del juego. Mostramos que disminuyen la complejidad de la implementación paralela, eliminando o reestructurando la sincronización explícita que es necesaria en las implementaciones de memoria compartida. También se observa una buena escalabilidad y una aceleración mejor, especialmente en el caso de un ambiente de juego muy cargado. En última instancia, sobre una máquina con ocho núcleos se ha obtenido una aceleración del 4.72x comparado con el código secuencial, y una mejora del 49% sobre la implementación paralela basada en locks.
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Monteillet, Aurélien. "Atomic Schrödinger Operator." Thesis, Uppsala University, Department of Mathematics, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-121420.
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Cunningham, David. "Locking atomic sections." Thesis, Imperial College London, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.516350.
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Schef, Peter. "Weak Atomic Interactions." Doctoral thesis, Stockholm : Physics Department, Stockholm University, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-1064.
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Bailey, Stephen Malcolm William. "Relativistic atomic photoionization." Thesis, Queen's University Belfast, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387976.
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Priedeman, Jonathan Lake. "Quantifying Grain Boundary Atomic Structures Using the Smooth Overlap of Atomic Positions." BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/6770.
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In this work, the relationship between grain boundary crystallography and grain boundary atomic structure is examined, using [1 0 0] - symmetric tilt grain boundaries in nickel. The structural unit model is used as a benchmark to evaluate the atomic structure description capacities of an emerging structural descriptor, the local environment representation, which itself is a refinement of the also-emergent Smooth Overlap of Atomic Positions (SOAP) descriptor. We show that the local environment representation encodes both the information of the structural unit model and additional information, such as distortion in the structural units and the arrangement of the structural units at the interface. The use of the local environment representation permits the use of a visualization tool known as SPRING to represent structural similarities between grain boundaries. With the SPRING representation, we produce objective evidence of a relationship between crystallography and atomic structure, at least for [1 0 0] - symmetric tilt grain boundaries.
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Liston, Gregory John. "The Atomic Trampoline Cavity." Thesis, University of Auckland, 1996. http://hdl.handle.net/2292/1913.
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Using an intense evanescent light wave as the lower mirror, and the gravitational force as the upper mirror, a vertical cavity for storing atoms can be constructed. Transverse confinement is obtained by totally internally reflecting the light off a concave as opposed to a planar crystal surface, which results in any atom reflected by the evanescent potential at a position away from the central axis receiving an impulse towards it. After a cursory discussion of atom optics and atomic cavities, we outline the configuration of the atomic trampoline cavity described above, and present analysis of the motion of atoms within it. A discussion of the classical dynamics and quantum modes in the cavity is given, together with other complicating factors which act as loss mechanisms out of the cavity. Various aspects of obtaining experimental realizations and applications of the cavity are considered. A detailed study of the quantum dynamics of atoms in the three dimensional cavity reveals that the dispersion can be adequately described in the transverse directions using a simulation involving a classical distribution of point-like atoms, where the probability density of finding an atom at a particular position in the simulation corresponds to the probability density of the atomic wavefunction. The classical simulations, however, significantly underestimate the spreading in the vertical direction. By calculating the modes of the atomic trampoline cavity, both in and out of the evanescent potential, the proportion of each of the modes in the excited state, and hence the decay rate, or linewidth due to spontaneous emission can be calculated. We found that even when the effect of the evanescent potential was included, the modes obtained correspond to those calculated by Wallis, Dalibard and Cohen-Tiennoudji [Appl. Phys. B 54,407 (1992)], who treated the bottom potential as infinitely steep and not exponentially decaying. In contrast to an optical Fabry-Pérot cavity, the linewidth was found to be strongly dependent on energy. Various other cavity parameters (finesse and Q) which depend on the loss due to spontaneous emission were also calculated. Using a ring cavity rather than a laser traveling wave to provide the light that totally internally reflects off the internal surface of the dielectric crystal, we can accumulate the phase change due to the single atom bouncing into and out of the evanescent wave and altering the refractive index of the cavity. A measurement of the phase of this light will reveal information about the atom. We found that the measurement did not significantly alter the mean or standard deviation of the atomic energy distribution across the modes of the cavity, as to first order the phase change of the light in the cavity is independent of the energy of the atom. The significant change in the energy distribution was the introduction of oscillations, which occurred when the phase measured was significantly different from the expected mean. The reason for these oscillations is that the measurement implies the weighting of modes just entering or leaving the evanescent wave should be increased or decreased. Ways of bringing this currently infeasible experiment closer to being achievable using novel design mechanisms are also discussed.
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McAlinden, Mary Trea. "Atomic collisions involving positrons." Thesis, Queen's University Belfast, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317480.
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Piccolomo, Savino. "Chip-scale atomic magnetometer." Thesis, University of Strathclyde, 2016. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=27528.
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Sataline, Christopher J. "Remotely-sensed atomic magnetometry." Thesis, Boston University, 2013. https://hdl.handle.net/2144/12213.
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Thesis (M.S.)--Boston UniversityCoherent population trapping (CPT) effects can be realized with frequency mod- ulated lasers and compact vapor cells of alkali metals such as Rubidium-87. Using these optical resonances, one can readily measure the hyperfine separation of this three-level atom. In the presence of a magnetic field, the Zeeman effect causes magnetic sublevels of these hyperfine ground states to split; the frequency of such splitting can be measured in an ensemble of Rubidium atoms with the magnetometer we have constructed. While other groups have constructed magnetometers based on these effects, none to our knowledge have investigated the capability to measure magnetic fields remotely. Most atomic-optical magnetometers,colocate the transmit and receive optical system with the vapor cell itself or require fiber optics at the location of the cell; our free-space technique with a reflective geometry lends itself to measurement at distances greater than could be achieved with those methods. We have developed a laboratory FM laser spectrometer that interrogates CPT resonances to measure magnetic fields with the vapor cell not necessarily co-located with the spectrometer. Its intrinsic linewidth (in the presence of transit-time broadening) is less than 30 kilohertz, which allows measurements on the order of 2 microtesla. We present results concerning the accuracy of the magnetometer at about one meter of standoff distance, and describe considerations for measurements at longer distances.
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Batdorf, Brian James. "Cesium atomic resonance filter." Diss., The University of Arizona, 1991. http://hdl.handle.net/10150/185406.
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An atomic resonance filter (ARF), composed of a cell containing an absorbing gas and two interference/absorption filter stacks, is designed to be both wide angle and ultra-narrowband. The bandwidth of this filter, in the range of 1-10mA, is determined by the absorption linewidth of the absorbing gas. Light entering the ARF within this bandwidth excites the gas to a highly excited state, and the fluorescence cascade back to the ground state emerges from the gas cell as the detected signal. The interference/absorption filter stacks insure that light not interacting with the gas does not pass through the ARF. The ARF is necessarily wide-angle due to the isotropic absorption properties of the gas. This dissertation models the processes involved in atomic absorption to determine the performance of an ARF that uses cesium as the absorbing gas. This model uses the Voigt absorption profile to obtain a correlation between the frequency of the traveling photon and the velocity of the absorbing atom. Results of computer simulations based on this model are presented along with experimental measurements. The ARF characteristics of importance include its efficiency and the temporal response of the filter. These characteristics are determined as a function of temperature and the input photon frequency. The effect of an additional buffer gas, which is included to decrease the ARF response time is investigated.
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Jonke, Alex P. "Atomic metal/polyaniline composites." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/49070.
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It is ideal to theoretically predict the activity of a catalyst. It has been recognized that not only the type of metal, but also its atomic size plays an important role in catalysis. In the past, atomic clusters have been created by sputtering from a sacrificial metal plate and then using a mass selector to choose cluster sizes from 1-233 atoms of gold. This approach has practical limitations. In this thesis, I describe a procedure by which atomic clusters of gold containing 1-8 atoms are deposited in polyaniline as an isolation matrix. My atomic deposition follows a cyclic pathway. Atomic clusters of palladium and atomic alloys of gold and palladium are also deposited in polyaniline using the same process. It is to show that this method will also work for other metals. These composite materials are characterized, and the catalytic activity for alcohol oxidation is evaluated.
This thesis is divided into seven chapters. The first chapter discusses the chemistry of polyaniline for using gold and palladium as catalysts. The technique developed to deposit the atomic clusters is discussed in the second chapter. This technique deposits one atom of metal per imine site on polyaniline, per cycle. The cycle is repeated n-times until a cluster of specified size, Mn, and composition has been synthesized. It is known that polyaniline plays an important role in stabilization of the formed clusters which prevents their aggregation. The optimization of this technique is the topic of the third chapter along with the description of how these composite films are produced. To end this chapter, the composite films are characterized by cyclic voltammetry, Kelvin probe, and X-ray photoelectron spectroscopy.
In chapters 4 and 5, the catalytic activity of the polyaniline/gold composites for the oxidation of alcohols in alkaline media using cyclic voltammetry is evaluated. In chapter 4, the correlation of the electrochemical activity for the oxidation of n-PrOH with the odd-even pattern from the calculated HOMO-LUMO gap energies for the same size clusters is shown. It is shown that the infrared spectrum of polyaniline with different sizes of atomic gold clusters also follows the odd-even pattern. Chapter 5 expands on the discussion of the catalytic oxidation of alcohols. The oxidation of methanol, ethanol, propanol, and butanol is surveyed. The peak currents are again dominated by the odd-even pattern.
In chapter 6, the versatility of the atomic deposition cycle is shown by depositing atomic palladium clusters. The peak currents for the oxidation of n-PrOH by these palladium composite films again follows the predicted pattern of the calculated HOMO-LUMO gap energies for atomic palladium clusters. This chapter also explores bimetallic atomic clusters of gold and palladium. The results indicate that the catalytic activity depends on the orientation of the cluster in the polyaniline matrix. Chapter 7 discusses the oxidation of methanol, ethanol, and isopropanol on AunPd1 bimetallic atomic clusters. The addition of palladium in the cluster increases the peak current densities for the oxidation of both alcohols except for the most stable of the atomic gold clusters, while it inactivated the electrodes for isopropanol. The possible future work for this project is discussed in chapter 8.
Overall, this thesis has developed a novel and unique technique for depositing atomic metal clusters into a polyaniline matrix. The technique is versatile enough to deposit atomic metal clusters other than gold, as shown by creating atomic palladium clusters and atomic bimetallic clusters of gold and palladium. This is extremely useful, since this single technique can produce many different types of atomic catalysts. The composite materials have been shown to be catalytically active for the oxidation of alcohols in alkaline media. This indicates a significant improvement to conserve precious metals while still retaining a high catalytic activity.
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Trypogeorgos, Dimitrios. "Periodically driven atomic systems." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:93785d4c-76d0-41c3-bf0a-5551108d8189.
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This thesis is concerned with a variety of topics grouped together under the general theme of periodically driven atomic systems. Periodic driving is ubiquitous in most techniques used in atomic physics, be it laser cooling, ion trapping or AC magnetic fields. An in-depth understanding of the behaviour of such systems can be provided through Floquet theory which will develop as a central theme in the following chapters. The thesis is divided in two parts: neutral atoms, and ions and biomolecules. In the first part I discuss a new 41K-87Rb mixture experiment, built during the first year of my DPhil. This species combination has some very broad and low-loss interspecies Feshbach resonances that are instrumental for carrying out the experiments discussed in the first chapter. Unfortunately, the mixture experiment had to be put aside and our attention was shifted to Time-Averaged Adiabatic Potentials (TAAPs) and how these can be extended using multiple Radio-Frequency (RF) fields. This technique opens up the way for precise interferometric measurements. Lastly, the peculiar behaviour of Modulation Transfer Spectroscopy (MTS) of 39K is investigated and a linearising transformation for four-wave mixing processes is presented. In the second part we turn our attention to charged ions and biomolecules and the techniques of ion trapping. We propose a novel technique for co-trapping charged particles with vastly different mass-to-charge ratios and thoroughly explore its consequences. The behaviour of the trap and the stability of equations with periodic coefficients in general is studied using Floquet theory. The normal modes and symmetries of the system also need to be considered in relation to the effectiveness of the sympathetic cooling of the ions. Small systems were simulated using a Molecular Dynamics (MD) approach in order to capture the effect of micromotion and other heating processes.
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Miles, Jessica. "Atomic Nanofabrication with Chromium." Thesis, University of Manchester, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.516404.
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Conkey, Donald B. "On-Chip Atomic Spectroscopy." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd1746.pdf.
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O'Connor, Daryl John. "Atomic collisions with surfaces." Thesis, Canberra, ACT : The Australian National University, 1997. http://hdl.handle.net/1885/144473.
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Olwell, Russell Brian. "Atomic workers, atomic city : labor and community in Oak Ridge, Tennessee, 1942-1950." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/9852.
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Binnie, Anna-Eugenia. "From atomic energy to nuclear science : a history of the Australian Atomic Energy Commission." [Sydney] : Macquarie University Physics Department, 2003. http://www.ansto.gov.au/libsite/Fulltext/Binnie_atomic-energy.pdf.
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Zheng, Ximeng. "Fiber post-processing and atomic spectroscopy for the development of atomic-vapour photonic microcell." Thesis, Limoges, 2017. http://www.theses.fr/2017LIMO0031/document.
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Cette thèse concerne la spectroscopie atomique pour le développement de microcellules photoniques à base de vapeur atomique alcaline (PMC). Le travail est motivé par reproduire les performances remarquables obtenues dans les domaines des références de fréquences et de l’optique cohérente en environnement laboratoire et à les transférer dans des dispositifs très compacts et autonomes accessibles à une communauté scientifique plus large ou à un marché commercial. Dans notre cas, ces futurs composants seront basés sur une fibre à cristal photonique à coeur creux (HC-PCF) remplie d'un matériau en phase gazeuse pour former la PMC et se distingue par une longueur d'interaction ultra longue associée à des dimensions modales transverses micrométriques. Cependant, cette échelle micrométrique du coeur creux de la fibre contenant les atomes soulève plusieurs défis techniques et scientifiques. Parmi les défis techniques, nous énumérons le développement d'un processus efficace pour le chargement d'atomes dans une telle fibre optique, la suppression ou l'atténuation de la réactivité physio-chimique des atomes (c'est-à-dire le rubidium) avec la surface interne silice entourant le coeur de la fibre, etc... En parallèle, le rapport large surface / volume du coeur de la fibre soulève des questions comme la dynamique de relaxation de la cohérence et la nature et l'effet de l'interaction atome-surface. Ainsi, les travaux de thèse reposent sur l’utilisation de revêtements spécifiques de la surface interne du coeur de la fibre avec différents matériaux pour atténuer ces réactions physico-chimiques, sur l'amincissement des larges coeurs creux des HC-PCF Kagomé à couplage inhibé et sur une technique de soudure qui garantit de faibles pertes d’insertion et l’absence de réactivité avec les atomes. Parallèlement, la thèse rapporte un ensemble d'expériences de spectroscopie pour évaluer la dynamique de relaxation des atomes à l'intérieur des HC-PCF et l’observation de nouvelles transparences sous-DopplerThis thesis reported on atomic spectroscopy for the development of alkaline atomic vapor photonic microcell (PMC). The work is motivated by reproducing the outstanding laboratory environment based performances achieved in the fields of frequency standard and coherent optics in highly compact and stand-alone devices that can be accessible to a wider scientific community or to a commercial market. In our case these future devices will be based a Hollow-core photonic crystal fiber (HC-PCF) filled with a gas phase material to form a PMC, and outstands with an ultra-long long interaction length and micrometric modal area. However, the micrometric scale of the fiber core harboring the atoms raises several technical and scientific challenges. Among the technical challenges, we list the development of efficient process for atom loading inside long hollow fiber with small core diameter, the suppression or mitigation of physio-chemical reactivity of the atoms (i.e. Rubidium) with the fiber core inner-surface silica etc. In parallel, the large surface-to-volume ratio of the fiber-core raises questions like the coherence relaxation dynamics and the nature and effect of the atom-surface interaction. The thesis reports on fiber-core inner surface coating with different materials to mitigate the physio-chemical reactions of the confined atoms with the surface, on tapering large core inhibited coupling Kagome HC-PCF, and splicing technique that ensures low splice loss and no atomic reactivity during the splicing process. In parallel, the thesis reports on a set of spectroscopy experiments to assess the relaxation dynamics of atoms inside HC-PCF and to report on novel sub-Doppler transparencies
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Matsukevich, Dzmitry. "Quantum networking with atomic ensembles." Diss., Available online, Georgia Institute of Technology, 2006, 2006. http://etd.gatech.edu/theses/available/etd-07072006-173336/.
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Thesis (Ph. D.)--Physics, Georgia Institute of Technology, 2007.Kennedy, Brian, Committee Member ; Chapman, Michael, Committee Member ; Kuzmich, Alex, Committee Chair ; Raman, Chandra, Committee Member ; Voss, Paul, Committee Member.
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Oelgoetz, Justin Ryan. "Atomic data and plasma spectroscopy." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1155738124.
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Zhang, Liang. "Stability analysis of atomic structures." Diss., University of Iowa, 2006. http://ir.uiowa.edu/etd/70.
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Roy, Amit Kumar. "Atomic Layer Deposition onto Fibers." Doctoral thesis, Universitätsbibliothek Chemnitz, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-85451.
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The main goal of this dissertation was to show that the principle of atomic layer deposition (ALD) can be applied to “endless” fibers. A reactor of atomic layer deposition has been designed, especially for coating depositions onto meter long bundles of fibers. Aluminum oxide (alumina), titanium oxide (titania), double layers of alumina and titania, as well as aluminium phosphate have been deposited onto bundles of carbon fibers using the home-built reactor. Scanning electron microscopic (SEM) and transmission electron microscopic (TEM) images indicate that the coatings were uniform and conformal onto fiber surface. There was a good adhesion of the coatings to the fibers. Alumina has been deposited using two separate aluminum sources (aluminum trichloride and trimethylaluminum), and water as a source of oxygen. In case of alumina deposition using aluminum trichloride and water, initial deposition temperature was 500 °C. In these conditions, a part of the fiber bundle has been damaged. Thus, the deposition temperature was decreased to 300 °C and the fibers were unaffected. In addition, during this process hydrochloric acid is formed as a byproduct which is a corrosive substance and affects the reactor and there was a chloride impurity in the coatings. Thus, aluminum trichloride precursor was replaced by trimethylalumium. Alumina deposition onto carbon fibers using trimethylaluminum and water was carried out at a temperature of 77 °C. SEM images revealed that the fibers were unaffected and the coatings were uniform and conformal. Oxidation resistance of the carbon fibers was improved slightly after alumina deposition. Oxidation onset temperature of the uncoated fibers was about 630 °C. The resistance was linearly increased with the coating thickness (up to 660 °C) and getting saturated over a thickness of 120 nm. Titania coatings have been deposited using titanium tetrachloride and water. The physical appearances of the titania coatings were similar to the alumina coatings. The oxidation onset temperature of the titania coated carbon fibers was similar to the uncoated fibers but the rate of oxidation was decreased than the uncoated fibers. Two double layer coatings were deposited, alumina followed by titania (alumina/titania), and titania followed by alumina (titania/alumina). If the fibers were coated with the double layer of alumina/titania, they had almost same oxidation onset as alumina coated fibers but the rate of oxidation was decreased significantly compared to alumina coated fibers. This feature is independent of the thickness of the titania layers, at least in the regime investigated (50 nm alumina followed by 13 nm and 40 nm titania). On the other hand, the oxidation onset temperature of fibers coated with titania/alumina (20 nm titania /30 nm alumina) was approximately 750 °C. The fibers were burned completely when temperature was further increased to 900 °C and held another 60 minutes at 900 °C. This is significantly better than any other coating used in this dissertation. ALD of titania and alumina in principle was known beforehand, this dissertation here applies this knowledge for the first time to endless fibers. Furthermore, this dissertation shows for the first time that one can deposit aluminum phosphate via ALD (planar surface as well as fibers). Aluminum phosphate might be special interest in the fiber coating because it is a rather soft material and thus might be used to obtain a weak coupling between fiber and matrix in composites. Aluminum phosphate was deposited using trimethylaluminum and triethylphosphate as precursors. Energy dispersive X-ray spectroscopy and solid state nuclear magnetic resonance spectra confirmed that the coating comprises aluminum phosphate (orthophosphate as well as other stoichiometries). Scanning electron microscopic images revealed that coatings are uniform and conformal. In cases of alumina and titania, it was observed that the coatings were delaminated from the ends of cut fibers and thus formed of clear steps. On the other hand, for aluminum phosphate coating it was observed that the border between coating and underlying fiber often being smeared out and thus formed an irregular line. It seems in case aluminum phosphate cohesion is weaker than adhesion, thus it might be act a weak interface between fiber and matrix. Alumina, titania, and double layer microtubes have been obtained after selective removal of the underlying carbon fibers. The carbon fibers were selectively removed via thermal oxidation in air at temperatures exceeding 550 °C. SEM and TEM images indicate that the inner side of the tube wall has the same morphology like the fibers. In addition, it was observed that the individual microtubes were separated from their neighbors and they had almost uniform wall thicknesses. The longest tubes had a length of 30 cmDas Hauptziel dieser Dissertation bestand darin nachzuweisen, dass die Atomlagenabscheidung (engl. atomic layer deposition (ALD)) auf „endlose“ Fasern angewendet werden kann. Es wurde ein Reaktor zur Atomlagenabscheidung gestaltet, der speziell für die Beschichtung meterlanger Faserbündel geeignet ist. Aluminiumoxid, Titanoxid, Doppelschichten aus Aluminiumoxid und Titanoxid sowie Aluminiumphosphat wurden mit Hilfe des selbstgebauten Reaktors auf Kohlefaserbündel abgeschieden. Rasterelektronenmikroskopische (REM) und transmissionselektronenmikroskopische (TEM) Aufnahmen zeigten, dass die Beschichtung auf den Fasern einheitlich und oberflächentreu war. Des Weiteren wurde eine gute Adhäsion zwischen Beschichtung und Fasern beobachtet. Das Prinzip der Beschichtung mit Titanoxid und Aluminiumoxid mit Hilfe der ALD war bereits vorher bekannt und im Rahmen dieser Dissertation jedoch erstmals auf "endlose" Fasern angewendet. Des Weiteren wird in dieser Dissertation erstmals gezeigt, dass es möglich ist, Aluminiumphosphat mittels ALD abzuscheiden (sowohl auf planaren Oberflächen als auch auf Fasern). Aluminiumphosphat könnte von besonderem Interesse in der Faserbeschichtung sein, da es ein relativ weiches Material ist und könnte daher als eine Art „schwacher“ Verbindung zwischen Faser und Matrix in Kompositen dienen. Die Oxidationsbeständigkeit von beschichten Kohlefasern wurde im Vergleich zu unbeschichteten Fasern bis zu einem gewissen Grad erhöht. Monoschichten von Aluminiumoxid und Titanoxid waren dafür wenig effektiv. Aluminiumphosphatbeschichtete Fasern waren deutlich besser geeignet als die beiden anderen. Eine Doppelschicht aus Titanoxid gefolgt von Aluminiumoxid verbesserte die Oxidationsbeständigkeit nochmals deutlich gegenüber allen anderen Beschichtungen, die in dieser Dissertation verwendet wurden. Mikroröhren aus Aluminiumoxid, Titanoxid und Doppelschichten wurden durch die selektive Entfernung der zugrunde liegenden Kohlefasern erhalten. Einzelne Mikroröhren waren von benachbarten Röhren getrennt und sie weisen eine nahezu einheitliche Wanddicke auf
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Parthey, Christian Godehard. "Precision Spectroscopy on atomic hydrogen." Diss., lmu, 2011. http://nbn-resolving.de/urn:nbn:de:bvb:19-139433.
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Hagman, Henning. "Atomic transport in optical lattices." Doctoral thesis, Umeå universitet, Institutionen för fysik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-38648.
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This thesis includes both experimental and theoretical investigations of fluctuation-induced transport phenomena, presented in a series of nine papers, by studies of the dynamics of cold atoms in dissipative optical lattices. With standard laser cooling techniques about 108 cesium atoms are accumulated, cooled to a few μK, and transferred into a dissipative optical lattice. An optical lattice is a periodic light-shift potential, and in dissipative optical lattice the light field is sufficiently close to resonance for incoherent light scattering to be of importance. This provides the system with a diffusive force, but also with a friction through laser cooling mechanisms. In the dissipative optical lattices the friction and the diffusive force will eventually reach a steady state. At steady state, the thermal energy is low enough, compared to the potential depth, for the atoms to be localized close to the potential minima, but high enough for the atoms to occasionally make inter-well flights. This leads to a Brownian motion of the atoms in the optical lattices. In the normal case these random walks average to zero, leading to a symmetric, isotropic diffusion of the atoms. If the optical lattices are tilted, the symmetry is broken and the diffusion will be biased. This leads to a fluctuation-induced drift of the atoms. In this thesis an investigation of such drifts, for an optical lattice tilted by the gravitational force, is presented. We show that even though the tilt over a potential period is small compared to the potential depth, it clearly affect the dynamics of the atoms, and despite the complex details of the system it can, to a good approximation, be described by the Langevin equation formalism for a particle in a periodic potential. The linear drifts give evidence of stop-and-go dynamics where the atoms escape the potential wells and travel over one or more wells before being recaptured. Brownian motors open the possibility of creating fluctuation-induced drifts in the absence of bias forces, if two requirements are fulfilled: the symmetry has to be broken and the system has to be brought out of thermal equilibrium. By utilizing two distinguishable optical lattices, with a relative spatial phase and unequal transfer rates between them, these requirements can be fulfilled. In this thesis, such a Brownian motor is realized, and drifts in arbitrary directions in 3D are demonstrated. We also demonstrate a real-time steering of the transport as well as drifts along pre-designed paths. Moreover, we present measurements and discussions of performance characteristics of the motor, and we show that the required asymmetry can be obtained in multiple ways.
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Carnally, Stewart Antoni Michael. "Carbon nanotube atomic force microscopy." Thesis, University of Nottingham, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491631.
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This thesis concerns the manufacture of carbon nanotube atomic force microscope (NTAFM) probes and their employment in the high-resolution imaging of biological macromolecules. Attention was focused initially on synthesis of carbon nanotubes and the refinement of the growth processes to obtain nanotubes of controlled dimensions. These growth processes were subsequently used to grow nanotubes directly onto AFM tips, followed by attempts at controlling the dimensions of these directly-grown nanotubes. Individually fabricated NTAFM probes are also described, along with attempts to optimise the strength of the AFM probe-nanotube interaction through the use of various hydrophobic coatings. NTAFM probes produced by both techniques, but predominantly through individually assembled probes using hydrophobic coatings, were used to image a range of natural and synthetic nucleic acid molecules and investigate the influence of the use of a nanotube probe on the dimensions observed.
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Andersson, Erika. "Quantum information and atomic networks." Doctoral thesis, Stockholm, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3068.
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Ayuel, Kuacgor Karlo. "Atomic current densities and magnetism." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2000. http://dare.uva.nl/document/80882.
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Judge, Andrew. "Alchemy in the atomic age." [Ames, Iowa : Iowa State University], 2008.
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Gagnon, Morris Alexis. "Nanolithography using an atomic microscope." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=80270.
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In this thesis, I study the nanolithography of gallium arsenide samples by local oxidation with an atomic force microscope (AFM). I examine the current theoretical descriptions of the reaction kinetics and compare the results to experimental data. The main goal is to characterize the AFM oxidation process such that high quality features can be routinely patterned. I also investigate the use of alternative oxidation environments in an attempt to improve the height and aspect ratio of the AFM local oxidation features. An alternative lithography technique involving scratching under a high contact force is also studied. Finally, I discuss the steps that are necessary in order to fabricate a quantum structure with the AFM local oxidation lithography technique.
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Anscombe, Marcel Philip. "Nonlinear optics with atomic coherence." Thesis, Imperial College London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.404378.
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Holdsworth, P. C. W. "Correlation effects in atomic diffusion." Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355755.
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Plimmer, Mark David. "Laser spectroscopy of atomic systems." Thesis, University of Oxford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329991.
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Nunn, Joshua. "Quantum Memory in Atomic Ensembles." Thesis, University of Oxford, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.526095.
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Lahiri, Jayeeta. "Interface Modifications with Atomic Monolayer." Scholar Commons, 2010. http://scholarcommons.usf.edu/etd/3641.
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Poser, Stefan. "Austin-Roadstar und Atomic Lab." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-139057.
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Davies, Hilary Jane. "An optically guided atomic fountain." Thesis, Durham University, 1999. http://etheses.dur.ac.uk/4580/.
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This thesis describes the development of a laser-cooling experiment aimed at efficient transfer of cold atoms over a short distance, for loading into a conservative atom trap. We detail the construction of a 3D magneto-optical trap (MOT) and perform characterisation measurements to optimise the number and temperature of the cold atoms. The atoms are launched vertically in a fountain from the MOT using a 'moving molasses' technique and a red-detuned far-off-resonant laser beam is used to guide them into an UHV chamber. Loading into the guiding beam is optimised with respect to the beam and MOT parameters. We demonstrate a maximum loading of 20% and guiding over a distance of more than 10 cm without loss of atoms. The atoms are delivered to the UHV chamber in a cloud with a transverse dimension of order 200 µm. We discuss the extension to continuous operation of the guided atomic fountain. The 3D MOT is replaced by a funnel with 2D trapping and 3D cooling which continuously extracts the cold atoms using moving molasses. A comparison between the flux of guided atoms obtained in a pulsed fashion from the 3D MOT and continuously from the funnel indicate that the pulsed case is a factor of ten more efficient. The difference is due to inferior loading from the funnel. The optically guided fountain is used to load an optical dipole trap in the UHV chamber, using an 'optical trap door'. No additional cooling is required. The dynamics of the atoms in the optical dipole trap are studied. We discuss multiple loading of a conservative trap with the view of accumulating more atoms than can be obtained in a MOT.
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Higgins, Katrina Bernadette. "Positron scattering by atomic hydrogen." Thesis, Queen's University Belfast, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317443.
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Scholz, Timothy Theodore. "Electron scattering by atomic hydrogen." Thesis, Queen's University Belfast, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335441.
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Thomas, Malcolm. "Electron scattering by atomic oxygen." Thesis, Queen's University Belfast, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337031.
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Smith, P. A. "Dynamics of chemiluminescent atomic reactions." Thesis, University of Nottingham, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372672.
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Harris, M. "Collisional effects in atomic spectra." Thesis, University of Newcastle Upon Tyne, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.352727.
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Duffield, Roger John. "Direct atomisation furnace atomic absorption." Thesis, University of Leeds, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.236310.
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Ritchie, Robert B. "Chemical routes to atomic nitrogen." Thesis, University of Aberdeen, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359346.
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Chapter 1 contains a general introduction and review of the field of atomic nitrogen chemistry. Included here is mention of the occurrences, generation, detection and analysis, reactions and uses of atomic nitrogen. A summary of previous work towards the chemical generation of atomic nitrogen in solution is given, this being stated as the overall aim of the thesis. This aim encompasses bond-breaking: (a) in nitrogen containing heterocycles upon mild photolysis or thermolysis, (b) in azidyl radicals. Chapter 2 describes the benzocinnoline N-imine system along with its isomeric 5H-dibenzo[1,2,3][d,f]triazepine with a view to the selective derivatisation of the latter. The photochemical and oxidative reactions of these systems are investigated by esr. 1H-Benzotriazole and selected derivatives are examined as triazenyl models for the triazepinyl system. Chapter 3 considers the chemistry of the 1,3,4-dioxazol-2-ones particularly the unreported 5-O-linked derivatives which are sought as possible precursors to the novel 1,3,4-dioxazolidine-2,5-diones themselves potential atomic nitrogen precursors. Chapter 4 concerns the 1,2,4-dithiazolidine-3,5-diones as potential atomic nitrogen precursors and two routes are pursued to the little reported unsubstituted parent 1,2,4-dithiazolidinedione. Chapter 5 departs from the heterocyclic theme of chapters 2-4 and considers the generation and fragmentation of the azidyl radical as a possible source of atomic nitrogen. Evidence for the production of atomic nitrogen from this radical, generated from the persulphate oxidation of azide anion, is discussed.
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He, Fanny. "The atomic lambda-mu calculus." Thesis, University of Bath, 2018. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.761031.
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A cornerstone of theoretical computer science is the Curry-Howard correspondence where formulas are types, proofs are programs, and proof normalization is computation. In this framework we introduce the atomic λμ-calculus, an interpretation of a classical deep inference proof system. It is based on two extensions of the λ-calculus, the λμ-calculus and the atomic λ-calculus. The former interprets classical logic, featuring continuation-like constructs, while the latter interprets intuitionistic deep inference, featuring explicit sharing operators. The main property of the atomic λ-calculus is reduction on individual constructors, derived from atomicity in deep inference. We thus work on open deduction, a deep inference formalism, allowing composition with connectives and with derivations, and using the medial rule to obtain atomicity. One challenge is to find a suitable formulation for deriving a computational interpretation of classical natural deduction. A second design challenge leads us to work on a variant of the λμ-calculus, the ΛμS-calculus, adding streams and dropping names. We show that our calculus has preservation of strong normalization (PSN), confluence, fully-lazy sharing, and subject reduction in the typed case. There are two challenges with PSN. First, we need to show that sharing reductions strongly normalize, underlining that only β, μ-reductions create divergence. Our proof is new and follows a graphical approach to terms close to the idea of sharing. Second, infinite reductions of the atomic calculus can appear in weakenings, creating infinite atomic paths corresponding to finite ΛμS-paths. Our solution is to separate the proof into two parts, isolating the problem of sharing from that of weakening. We first translate into anintermediate weakening calculus, which unfolds shared terms while keeping weakened ones, and preserves infinite reductions. We then design a reduction strategy preventing infinite paths from falling into weakenings.
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Stein, Andrew John 1978. "A metrological atomic force microscope." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/16885.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2002.Includes bibliographical references (p. 245-248).
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
This thesis describes the design, fabrication, and testing of a metrological atomic force microscope (AFM). This design serves as a prototype for a similar system that will later be integrated with the Sub-Atomic Measuring Machine (SAMM) under development in collaboration with the University of North Carolina at Charlotte. The microscope uses a piezoelectric tube scanner with a quartz tuning fork proximity sensor to image three-dimensional sample topographies. The probe position is measured with a set of capacitance sensors, aligned so as to minimize Abbe offset error, for direct measurement of probe tip displacements. A PC-based digital control system provides closed-loop control of the lateral scanning and axial height regulation actions of the probe assembly. The lateral scanning system, which dictates the probe's motion in directions parallel to the sample plane, has measured -3 dB closed-loop bandwidths of 189 Hz and 191 Hz in the X and Y directions, respectively. Meanwhile, the axial height regulator, which adjusts the length of the tube scanner to control for a constant gap between the probe tip and the sample surface, has demonstrated a -3 dB closed-loop bandwidth of as high as 184 Hz. The metrological AFM is operational and has been used to collect several images of sample surfaces. Images taken of a silicon calibration grating indicate that the microscope can easily resolve 100 nm-scale step changes in height. However, several errors are observed in the image data. Possible reasons for these errors are discussed, and ideas for follow-on work are suggested.
by Andrew John Stein.
S.M.
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Harczuk, Ignat. "Atomic decomposition of molecular properties." Doctoral thesis, KTH, Teoretisk kemi och biologi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-187168.
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In this thesis, new methodology of computing properties aimed for multipleapplications is developed. We use quantum mechanics to compute propertiesof molecules, and having these properties as a basis, we set up equations basedon a classical reasoning. These approximations are shown to be quite good inmany cases, and makes it possible to calculate linear and non-linear propertiesof large systems.The calculated molecular properties are decomposed into atomic propertiesusing the LoProp algorithm, which is a method only dependent on the overlapmatrix. This enables the expression of the molecular properties in the two-site atomic basis, giving atomic, and bond-centric force-fields in terms of themolecular multi-pole moments and polarizabilities. Since the original LoProptransformation was formulated for static fields, theory is developed which makesit possible to extract the frequency-dependent atomic properties as well. Fromthe second-order perturbation of the electron density with respect to an externalfield, LoProp is formulated to encompass the first order hyperpolarizability.The original Applequist formulation is extended into a quadratic formula-tion, which produces the second-order shift in the induced dipole moments of thepoint-dipoles from the hyperpolarizability. This enables the calculation of a to-tal hyperpolarizability in systems consisting of interacting atoms and molecules.The first polarizability α and the first hyperpolarizability β obtained via theLoProp transformation are used to calculate this response with respect to anexternal field using the quadratic Applequist equations.In the last part, the implemented analytical response LoProp procedureand the quadratic Applequist formalism is applied to various model systems.The polarizable force-field that is obtained from the decomposition of the staticmolecular polarizability α is tested by studying the one-photon absorption spec-trum of the green fluorescent protein. From the frequency dispersion of thepolarizability α(ω), the effect of field perturbations is evaluated in classicaland QM/MM applications. Using the dynamical polarizabilities, the Rayleigh-scattering of aerosol clusters consisting of water and cis–pinonic acid moleculesis studied. The LoProp hyperpolarizability in combination with the quadraticApplequist equations is used to test the validity of the model on sample wa-ter clusters of varying sizes. Using the modified point-dipole model developedby Thole, the hyper-Rayleigh scattering intensity of a model collagen triple-helix is calculated. The atomic dispersion coefficients are calculated from thedecomposition of the real molecular polarizability at imaginary frequencies. Fi-nally, using LoProp and a capping procedure we demonstrate how the QM/MMmethodology can be used to compute x-ray photoelectron spectra of a polymer.I denna avhandling utvecklas ny metodik för beräkningar av egenskaper medolika tillämpningar. Vi använder kvantmekanik för att beräkna egenskaper hosmolekyler, och använder sedan dessa egenskaper som bas i klassiska ekvationer.Dessa approximationer visas vara bra i flera sammanhang, vilket gör det direktmöjligt att beräkna linjära och icke-linjära egenskaper i större system.De beräknade molekylära egenskaperna delas upp i atomära bidrag genomLoProp transformationen, en metod endast beroende av den atomära överlapps-matrisen. Detta ger möjligheten att representera en molekyls egenskaper i entvåatomsbasis, vilket ger atomära, och bindningscentrerade kraftfält tagna frånde molekylära multipoler och polarisabiliteter.Eftersom att den originella LoProp transformationen var formulerad medstatiska fält, så utvecklas och implementeras i denna avhandling LoProp meto-den ytterligare för frekvensberoende egenskaper. Genom den andra ordnin-gens störning med avseende på externa fält, så formuleras LoProp så att di-rekt bestämning av första ordningens hyperpolariserbarhet för atomära po-sitioner blir möjlig. De ursprungliga Applequist ekvationerna skrivs om tillen kvadratisk representation för att göra det möjligt att beräkna den andraordningens induktion av dipolmomenten för punktdipoler med hjälp av denförsta hyperpolariserbarheten. Detta gör det möjligt att beräkna den totalahyperpolariserbarheten för större system. Här används den statiska polariser-barheten och hyperpolariserbarheten framtagna via LoProp transformationenför att beräkna ett systems egenskaper då det utsätts av ett externt elektrisktfält via Applequists ekvationer till andra ordningen.Tillämpningar presenteras av den implementerade LoProp metodiken medden utvecklade andra ordnings Applequist ekvationer för olika system. Detpolariserbara kraftfältet som fås av lokalisering av α testas genom studier avabsorptionsspektrat för det gröna fluorescerande proteinet. Via beräkningar avden lokala frekvensavhängande polariserbarheten α(ω), testas effekten av de ex-terna störningar på klassiska och blandade kvant-klassiska egenskaper. Genomden linjära frekvensberoende polariserbarheten så studeras även Rayleigh sprid-ning av atmosfärs partiklar. Via LoProp transformationen av hyperpolariser-barheten i kombination med de kvadratiska Applequist ekvationerna så un-dersöks modellens rimlighet för vattenkluster av varierande storlek. Genom attanvända Tholes exponentiella dämpningsschema så beräknas hyper-Rayleighspridningen för kollagen. Den atomära dispersionskoefficienten beräknas via delokala bidragen till den imaginära delen av den linjära polariserbarheten. Slutli-gen visar vi hur LoProp tekniken tillsammans med en s.k. inkapslingsmetod kananvändas i QM/MM beräkningar av Röntgenfotoelektron spektra av polymerer.
QC 20160517