Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 21 for “"resonant scattering"”.
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Investigating the low-frequency stability of BiSON's resonant scattering spectrometers
… Birmingham Solar Oscillations Network (BiSON) Resonant Scattering Spectrometers (RSS). To that end we present a novel model of the RSS and its observations that allows for the determination of a significant improvement in calibration for ground-based Sun-as-a-star Doppler velocity observations. …
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Application of the resonant rotating wave approximation to the theory of resonant scattering
A theoretical study of the resonant scattering of light, including the effects of strong fields, is reported. The formulation is developed within the context of a new approximation, the resonant rotating wave approximation (RRWA). The RRWA is similar to the standard R\-lA, except that non-resonant …
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X-ray scattering studies of strongly correlated materials: orbital ordering in KCuF3 and stripe-like domain structures in BiFeO3 epitaxial thin films
The results of x-ray scattering experiments on orbitally ordered KCuF3 and periodic arrays of stripe-like ferroelectric domains in epitaxial thin films of multiferroic BiFeO3 are presented in this dissertation. Both resonant soft x-ray elastic scattering and non-resonant hard x-ray elastic …
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Nuclear Forward-Scattering of Synchrotron Radiation From Krypton: First Observation and Application to the Study of Lattice Dynamics in Near-Monolayer Krypton-on-Graphite
<p>Since 1985 nuclear-resonant scattering, and in particular nuclear forward-scattering, of synchrotron radiation has been observed in a select few Mossbauer isotopes including: <sup>57</sup>Fe, <sup>119</sup>Sn, <sup>169</sup>Tm. For the first time, nuclear forward-scattering from the 9.4 keV …
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Structural studies using synchrotron X-ray powder diffraction and other techniques
… Pnma) transition. Chapter 5 describes a resonant scattering experiment done on CsI. Resonant scattering parameters have been refined from synchrotron X-ray powder diffraction data collected at room ' temperature ,md al -+ K close to the Cs and I K-edges. The refined f parameters are …
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Spectral modelling of molecular nitrogen in Aurora
… and 15.829E). The filter provides images of the resonant scattered spectra of N+2 1N (0,1), (1,2), (2,3) bands and a neutral N2 2P (0,3) band. Ab initio models were created for describing the populations of vibrational and rotational energy levels in both excited and ionised N2 molecules in the …
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The thermal conductivity of double nitrate crystals below 1 K
… nitrate crystals is determined by an internal scattering mechanism which is approximately independent of frequency. The phonon mean free paths, calculated in the usual way from the thermal conductivities of the individual samples, were appreciably greater than the smallest dimensions of the …
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Lyα emission as a sensitive probe of galactic mergers and reionization
… boosting Lyα luminosity. Additionally, resonant scattering produces extended red wings in the line profiles, which enhance transmission through the neutral intergalactic medium (IGM). Our simulations successfully reproduce several JWST observations with the assumption of minimal …
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Guided modes and resonant transmission in periodic structures
We analyze resonant scattering phenomena of scalar fields in periodic slab and pillar structures that are related to the interaction between guided modes of the structure and plane waves emanating from the exterior. The mechanism for the resonance is the nonrobust nature of the guided modes with …
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The Effect of Minor Elements on the Physical and Chemical Properties of Lower Mantle Minerals at High-Pressure
… the sound velocities, as well as novel nuclear resonant scattering of synchrotron radiation to investigate the electronic state of iron (which is thought to influence material properties) in candidate lower mantle minerals. I performed high-pressure Brillouin spectroscopy measurements to …
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Low temperature anomalies in niobium, vanadium and tantalum
… has been observed in the specific heat. Phonon scattering caused by the addition of H to Nb or Ta is complicated by the presence of resonant scattering from dislocations produced by precipitation of the ~-phase hydride. A technique has been developed which permits the accurate measurement of …
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Scalable Plasmonic Nanopixels
… shell electrically, thus rapidly shifting the resonant scattering colour of the eNPoM across over 100 nm wavelength ranges, in response to less than 1 V. As the whole construction process is solution-based, electrically-driven colour-changing metafilms can be fabricated by coating these …
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Dynamic Acoustic Control of Semiconductor Quantum Dot-Based Devices for Quantum Light Generation
… generation of entangled photon chains by resonant scattering of a laser field on a single charged particle in a cavity-enhanced quantum dot. The charge has an associated spin that can determine the time bin of a photon, allowing for information encoding in this degree of freedom. We …
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Patterned zero-dimensional nanostructures: fabrication and characterization
… periodicity results in miniband formation due to resonant scattering. Theoretical calculations of the intersubband scattering rate in nanopore lattices predict decreased intersubband scattering rates. This is due to the reduced overlap between in-plane components of the initial and final …
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Magnetische Streuung an Grenz- und Viellagenschichten
… in dünnen Schichtsystemen zu bestimmen. Diese Resonante Magnetische Röntgenreflektometrie (XRMR: X-ray Resonant Magnetic Reflectometry) kombiniert die Methode der konventionellen Röntgenreflektometrie mit resonanten magnetischen Effekten, die an Absorptionskanten magnetischer Atome auftreten. …
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Improvements to the modelling of radiowave propagation at millimetre wavelengths. In-depth studies are reported on resonance phenomena in the scattering of spherical ice particles, extinction and backscattering properties of clouds and on the absorption and dispersion spectra of atmospheric gases.
… Interference and resonance phenomena in the scattering of spherical ice and water particles are reviewed. The long standing problem of the numerous resonances observed in the scattering diagrams of dielectric spheres is answered. The spatial structure and the physical characteristics of …
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Using high pressure to study thermal transport and phonon scattering mechanisms
… conductance. Away from interfaces, phonon-defect scattering is arguably the most complex, and technologically relevant, thermally resistive scattering mechanism in nonmetallic crystals. My primary experimental tools are the diamond anvil cell (DAC) coupled with time-domain thermoreflectance …
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Magnetic X-ray Reflectivity
… and artificial multilayer systems. The theory of resonant magnetic scattering within dipole approximation combined with the specular reflectivity condition suggests that the strongest effects are in the lower incident angle regime using circularly polarized x-rays. By using soft and hard x-rays …
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