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Showing 1 to 20 of 42 for “"Enhanced diffusion"”.
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Effect of point defect generation on transient enhanced diffusion
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1994.
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Radiation-Enhanced Diffusion of Lanthanum in Cerium Dioxide Thin Films
Made available in DSpace on 2017-07-06T18:55:45Z (GMT). No. of bitstreams: 3 Pappas_Harrison_K_MS.pdf: 1482565 bytes, checksum: 2933869aff9af3322ffa74df3c73cca3 (MD5) Pappas_Harrison_K_MS_ABS.pdf: 89237 bytes, checksum: ddab93aa3b35515e29bd40e2482647cd (MD5) license.txt: 4813 bytes, checksum: …
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Working Up Hills: Dynamics over Sloping Topography with Bottom-Enhanced Diffusion
… equations plus advection-diffusion of a sole tracer, potential temperature. Preliminary simulations confirmed that both models were capable of simulating the desired phenomena, notably an upslope flow along the topography, and had otherwise comparable results. Two …
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Modeling and Control of Transient Enhanced Diffusion of Boron in Silicon
Reducing the junction depth using rapid thermal annealing with high heating rates comes at a cost of increasing sheet resistance. A model-based optimization is formulated to design the optimal annealing temperature program that gives the minimum junction depth while maintaining satisfactory sheet …
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A systematic study of radiation enhanced diffusion; theoretical improvement and application
A new rate theory model for the radiation enhanced diffusion (RED) has been developed. To improve the traditional mean-field theory, which assumes all defects are produced uniformly and continuously in the form of Frenkel pairs under irradiation, the new model considers more realistic defect …
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Radiation-enhanced diffusion of oxygen-18 in uranium dioxide thin films
Anion radiation enhanced diffusion (RED) and thermal diffusion of a buried 18O tracer layer in thin film UO2 was measured using Secondary-Ion Mass Spectroscopy (SIMS). Thin films were grown using a dedicated magnetron sputtering chamber. Samples were irradiated with 1.8 MeV Kr+ over a temperature …
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Radiation enhanced diffusion of neodymium in single crystal thin film UO2
Radiation-enhanced diffusion (RED) of a Nd buried tracer layer in UO2 thin films was measured with Secondary Ion Mass Spectrometry (SIMS). Samples were irradiated with 1.8 MeV Kr+ over a temperature range from 400 to 800 C. RED in UO2 was found to be in the recombination limited regime. Dose rate …
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Direct Single Molecule Imaging of Enhanced Diffusion for Enzymes and Enzyme-conjugated Dna origami
… we revealed new insights into this process of enhanced diffusion using single-particle tracking (SPT) with total internal reflection fluorescence (TIRF) microscopy. We found that the mobility of individual enzymes was enhanced three-fold in the presence of the substrate, and the motion remained …
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Radiation-Enhanced Diffusion and Defect Production During Ion Irradiation of MgO and Al(2)O(3)
Radiation enhanced diffusion of O$\sp{18}$, Ca and Zn buried tracer layers in MBE grown MgO was measured following irradiation with either 2.0 MeV Kr or 1.0 MeV Ne, He or H from 30 to 1500$\sp\circ$C. This represents the first reported RED measurements on an oxide system. Ion beam mixing at …
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Atomic transport mechanisms in irradiated copper(3)-gold alloy
… were investigated by examining the radiation-enhanced diffusion and radiation-induced order-disorder kinetics in the ordered intermetallic alloy Cu$\sb3$Au.
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Materials Design for Advanced Nuclear Energy Systems: Refractory High Entropy Alloys and Metallic Multilayer Composites
… gives insight to radiation damage, solid–state diffusion, and other vacancy–driven material behavior. To test the validity of the model, I synthesize and characterize 5 refractory HEA compositions: NbMoTaTiW, NbMoTaTiV, NbMoTaTiZr, NbMoTaHfW, and WTaVTiCr. Implications for single phase HEA …
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Grain boundary self-diffusion in sodium chloride
"The diffusion of ²²sodium and ³⁶chlorine along tilt and twist grain boundaries in pure and calcium chloride doped sodium chloride bicrystals was investigated. No enhanced diffusion of ²²sodium along the grain boundaries was observed. Between 400°C and 500°C the chlorine grain boundary diffusion …
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The effect of irradiation temperature on REBCO Jc degradation and implications for fusion magnets
… in Jc degradation was found to be radiation-enhanced diffusion at higher temperatures, leading to grain boundary widening between superconducting crystals which in turn blocked supercurrent transport through the conductor. Molecular dynamics simulations suggest that the same mechanism …
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Dynamics from an equilibrium lattice model of a microemulsion
… exponent is related to the normal, inhibited and enhanced diffusion behaviors of the system.</p>
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Low Energy Ion Bombardment Effects in Supersaturated Copper-Indium Alloys
… while reduced, remained supersaturated and enhanced diffusion to ion bombardment-created point defect sinks resulted in the volume precipitation of randomly dispersed In-rich (delta) phase ((TURN) 30at%In) particles in the near-surface region. Thermally induced precipitates, on the other …
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Diffusion and Electrical Properties of Sulfur Implanted in Gallium-Arsenide
The diffusion and electrical properties of implanted sulfur in GaAs have been investigated with secondary ion mass spectrometry (SIMS) and differential resistivity and Hall measurements. Low dose (7 x 10('12) cm('-2), 250 keV) S implants exhibit redistribution behavior upon annealing which …
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Microstructural evolution of zirconium carbide (ZrCₓ) ceramics under irradiation conditions
… foils induce atomic mixing via radiation enhanced diffusion (RED), producing surface oxidation of the TEM foil.</p>
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Phonophoresis and topical drug delivery
… molecules are more susceptible to ultrasound-enhanced diffusion through the water-filled channels of the agar gel. The application of heat alone increased drug migration by a similar magnitude as the ultrasound, indicating that ultrasonic heating directly increases the thermodynamic potential …
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Shear induced mixing and self-organization in immiscible alloys during severe plastic deformation
… activation energy (0.39 eV). At 400 C, shear enhanced diffusion is observed at highest deformation rates. The results suggest that shear induced vacancies play a dominant role during self-organization.
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Applications of Spectrally-Resolved Photoluminescence in Silicon Photovoltaics
… silicon wafers, the defects induced by the post-diffusion thermal treatment at different depths below the wafer surface, and the enhanced diffusion at grain boundaries and sub-grain boundaries in multicrystalline silicon wafers. The results show that, the enhanced diffusion happens at both grain …
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