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 13 of 13 for “"UV emission"”.
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Enhancement of the UV emission in metal nanoparticle-coated ZnO
Large emission enhancement factors resulting from orders of magnitude increases in ultra-violet (UV) luminescence in ZnO have been reported, due to the presence of a surface coating of either Au or Al nanoparticles. Two significantly different models have been proposed to explain the observed …
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Optimisation and fabrication of ultra violet emitting CuC1 thin films by RF sputtering
… are the two major deciding factors for the UV emission from the film. We have successfully controlled both these properties by varying the sputtering parameters. Chemical stoichiometry was mainly controlled by the spacing between the target and substrate. An optimum spacing of 6 cm was found …
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The Host Galaxies of Luminous Reddened Quasars at z~2
… quasars is being able to disentangle the galaxy emission from that of the quasar. With combined observations from the Dark Energy Survey (DES), the VISTA Hemisphere Survey (VHS) and the UKIDSS Large Area Survey (ULAS), we exploit the quasar dust extinction in our sample to demonstrate that the …
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Building galaxy models with self-consistent prescriptions for stellar and nebular emission
… dust in galaxies, but most neglect the nebular emission from ionized gas. Accounting for nebular emission is important, as both line and continuum emission can contribute significantly to the total observed flux. The goal of this thesis is to include and exploit a proper accounting of emission …
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Ultrafast Dynamics and Nonlinear Interactions in Alkali Atoms and Diatomics
… spatially and temporally coherent pulses of UV radiation. Wave packets are produced by coherently exciting an ensemble of states using the broad bandwidth of a femtosecond pulse. Oscillations corresponding to the energy differences between the levels in the wavepacket are superimposed on the …
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UV/ozone induced oxidation of silicon(1-x) germanium(x) alloys and thermal desorption of the oxide film
… examines the fundamental issues associated with UV/ozone induced oxidation of Si$\sb{\rm 1-x}$Ge$\sb{\rm x}$ alloys and thermal desorption of the oxide film. A low temperature technique has been demonstrated for cleaning Ge wafer surfaces for the growth of high quality epitaxial films. Using …
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Remote sensing of ion-neutral charge exchange and diffusive transport in planetary atmospheres
… 80 km using observations of its ultraviolet (UV) emission, and co-incident constraints on the peak mesospheric [H] and φlimiting. The results provide the first ever quantification of solar cycle and local time asymmetry of [H] along with the partitioning of its escape to space via thermal …
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Low temperature carbon material deposition with photo-enhanced chemical vapor deposition
… to other commonly employed hydrocarbons in the UV emission spectrum from a Xe arc lamp, is selected as a carbon precursor in this work. Extensive experimentation conducted by varying Al/Ni/Al catalyst layer thicknesses on SiO2 coated Si substrates, substrate annealing temperature in the range …
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Quantification of the spatial structure and temporal variability of Earth's exosphere using optical tomography
… tomographic inversion of scattered H Ly-a emission. This approach avoids the historical dependence on ad hoc parametric formulations of the H density distribution and enables more reliable characterization of global outer exospheric. The incorporation of the temporal domain into the …
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Dynamique et composition des atmosphères supérieures de Mars et Vénus observées par les spectrographes ultraviolets à bord de Mars Express et Vénus Express
… I discuss the altitude and brightness of the emission peak (60 kR at 115 km) and show that the emission profile exhibits a secondary peak in ~10% of the cases. This additional peak is probably caused by upward-moving gravity waves propagating from below. I have developed an inversion method of …
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MOVPE growth and characterization of Al(Ga)N and InAlN/AlGaN quantum wells for UV LED applications
… as sample wafers for fabrication of ultraviolet (UV) LEDs, in order to replace the conventional bulky, expensive and environmentally harmful mercury lamp as new UV light sources. For application to UV LEDs, reducing the threading dislocation density (TDD) in AlN epilayers on sapphire substrates is …
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An Exploration of the Feasibility of Combining Radiation Therapy with Psoralen Phototherapy
… (phosphors) converts kV photon to ultraviolet (UV) light, which in turn activates psoralen. Radiotherapy Enhanced with Cherenkov photo-Activation (RECA) is another approach, where therapeutic megavoltage (MV) x-ray generates UV light via Cherenkov phenomenon. Both approaches could increase local …
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Preparation and characterization of AlGaN structures for UVA LEDs
Visible / UV LEDs are developed from the same III-Nitride compounds semiconductor materials and share many design and technological aspects. However, the efficiency difference between the two types is quite significant, where the latter lags. Recent advancements in material technology such as the …