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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 65 for “"flux ratio"”.
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Growth Kinetics of GaN and Effects of Flux Ratio and Growth Temperature on Properties of Undoped and Mg-Doped GaN Films Grown by PAMBE
… the background carriers. By supplying a high Mg flux, heavily doped p-type GaN films are obtained. The observation of a very smooth surface for the Mg-doped films grown at T$\sb{\rm s} \ge$ 650$\sp\circ$C suggests a layer-by-layer growth mode with good crystallinity. This fact is due to a large …
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Star formation in the presence of magnetic fields: Molecular cloud core formation and dynamical contraction due to ambipolar diffusion; a simulation with axial symmetry
… density increases, redistribution of the mass-to-flux ratio in a cloud's central flux tubes (ambipolar diffusion) takes place at an ever-increasing rate, leading to the formation of high-density cores, typically after 8 million years of quasi-static contraction. Eventually, the central …
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Experimental investigation of liquid fragmentation in hypersonic cross flow
… investigation carried out to study penetration and fragmentation of liquid injected into Mach 6 hypersonic cross flow. Flow topology, shock and vortex systems, fragmentation and atomization mechanisms are investigated using high-speed photography, Schlieren photography, flow visualization …
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Experimental Investigation of a Flush-Walled, Diamond-Shaped Fuel Injector for High Mach Number Scramjets
… of 3.54 mm and a jet-to-freestream momentum flux ratio of 1.04. Second, a lower mass flow rate of 1.5 g/s corresponding to an effective ratio of 2.35 mm and a jet-to-freestream momentum flux ratio of 0.49 was studied. The diamond injector was tested both aligned with the freestream and at a …
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The Effect of Blade Row Interaction on Rotor Film Cooling
… to 31% with cylindrical holes at a low momentum flux ratio, because the response to perturbations is non-linear. Cylindrical holes at a high momentum flux ratio, and fan-shaped holes, are robust to unsteadiness because they respond linearly. Non-film-resolved computations are used to identify the …
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Surface ordering of MBE grown 001 gallium(05) aluminum(05) arsenic: A theoretical study
… in the model are adsorption and surface migration. The surface ordering kinetics is studied as function of fluxes, flux ratio and substrate temperature. The growth parameters employed for the monatomic spices As are: fluxes 2{dollar}\sp\circ{dollar} A/sec, for cations with the cation to …
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Plasma-Assisted Molecular Beam Epitaxial Growth of Indium Nitride for Future Device Fabrication
… growth modes was created by varying the In/N flux ratio and growth temperature. A transition from a 2D to a 3D growth mode can be realized by lowering both the flux ratio (changing to an N rich growth) and the growth temperature.</p> <p>Structural characterization of MBE grown InN was …
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Statistical analyses of gravitational microlensing probability densities
… the likelihood for microlensing to account for flux ratio anomalies between macro-models and observations. We apply this tool to the study of iPTF16geu, a recently discovered type IA lensed supernova, and determine that it is unlikely for microlensing alone to account for flux ratio anomalies. …
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Systems metabolic engineering of Arabidopsis for increased cellulose production
… years. Using sophisticated algorithms, such as flux balance analysis, OptKnock, and OptForce, we can predict flux distributions and design metabolic engineering strategies at a greater efficiency. The caveat of these current methods is the accuracy of the predictions. We proposed using flux …
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Shear Effects on Buoyancy-Generated Turbulence and Salt Fingers
… favorable conditions. Effects of shear on the flux ratio are small. The laboratory experiment also produces results similar to the linear theory. Even though the bulk mixing rate increases as the density ratio decreases, the heat flux is larger than the salt flux, and no strong signature of …
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Phase Composition, Microstructure, and Physical Properties of Poly- and Single-Crystal Tantalum Nitride Layers
… nearly complete dense 002 by varying ion-to-Ta flux ratio Ji/JTa from 1.3 to ≥7.4. The change in texture is primarily due to an increased steady state atomic N coverage, resulting from collisionally-induced dissociative chemisorption of incident energetic N+2 ions, with increasing Ji/JTa.
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Fragmentation of magnetically-supported, weakly-ionized molecular clouds
… which varies the ionization fraction, mass-to-flux ratio, and velocity perturbation in the model clouds.
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Impact of time and spatial averages on the energy balance closure
… because their contribution to the turbulent fluxes is missed by a fixed eddy-covariance tower measurement that has a typical averaging time of 30 minutes. In this thesis, data from the LITFASS-2003 experiment was used to investigate the impact of time and spatial averages on the energy …
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Measurement of the Fluorine, Sodium, and Aluminum Fluxes in Cosmic Rays with the AMS Experiment on the International Space Station
… Precise knowledge of the secondary-to-primary flux ratio, like B/C, is essential in the understanding of cosmic ray propagation. This thesis presents the first precision measurements of the heavy cosmic ray fluorine (F), sodium (Na), and aluminum (Al) fluxes in the rigidity range from 2.15 GV …
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Fabrication of metal-oxide thin-films and features on dissimilar materials via ion-assisted codeposition
… beams are installed in a perpendicular configuration, with one normal to the substrate surface and the other parallel. The parallel beam passes over the substrate and impinges on a Zn target, sputter depositing the material onto the substrate. Simultaneously, the normal incidence beam impinges …
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Experimental Studies of Injector Array Configurations for Circular Scramjet Combustors
… Mach number, and jet-to-freestream momentum flux ratio on the fuel-air mixing process. Helium, methane, and air injectants were studied to vary the injectant molecular weight over the range of 4-29. All of these experiments were performed to support the needs of an integrated experimental and …
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Ultra-High B Doping During Si(1-X)ge(x)(001) Gas-Source Molecular-Beam Epitaxy: A Mechanistic Study of Layer Growth Kinetics, Dopant Incorporation, Electrical Activation, and Carrier Transport
CB in Si1-xGex(001) increases with precursor flux ratio and B is incorporated into active sites at concentrations to C*B (Ts) = 2.5 x 1020 and 4.6 x 1020 cm-3 for x = 0 and 0.18 at Ts = 600 and 500°C, respectively. At higher B concentrations, there is a large decrease in the activated fraction …
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The distribution of dark matter at large scales and in gravitational lenses
… research study presented here concerns the flux ratio anomaly in the quadruply imaged strong gravitational lens, B1422+231, in which the contribution of $10-10^3M_{\odot}$ primordial black holes (PBHs) as a potential dark matter constituent is examined. I review the theory of gravitational …
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The sum of the 1D magnifications along the axis of positive curvature for a smooth gravitational potential with N point perturbations
… and dark matter condensations. In particular, flux ratio anomalies- disparities between predicted and observed magnifications of images- have led astronomers to study the role of perturbations in determining image brightness. In this paper, we explore the limits of demagnification due to point …
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Measurement of cosmic antiprotons with the alpha magnetic spectrometer aboard the International Space Station
… measurement of the cosmic antiproton ( -p) flux and the antiproton-to-proton flux ratio ( -p/p) made with the Alpha Magnetic Spectrometer aboard the International Space Station is presented. The measurement covers the absolute rigidity range from 1 to 450 GV, and is based on 3.49x105 -p …
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