DEVELOPMENT OF NEW RENAL FUNCTION IMAGING AGENTS

Not Available Micro-gas turbine devices may offer the potential for power densities equivalent to today's large-scale power generation in small man-portable units. Successful implementation of such devices is dependent on the development of a refractory material capable of operating at high temperatures and extremely high stress levels. Semiconductor micro-fabrication techniques combined with chemical vapor deposited (CVD) silicon carbide process technology is being explored for producing MEMS-type turbine rotors. The fabrication of relatively thick (100-500 micron) devices is currently limited by the strength, residual stresses, and inadequate conformal coverage that is attributable to the columnar grain growth of thick vapor-deposited SiC. This Phase I program proposes to solve these limitations by producing a Nanolayered CVD SiC. Nanolayering of the CVD SiC structure is expected to result in enhanced strengths due to reduced grain size. The reduced grain size is critical as feature dimensions in potential high temperature MEMS decrease in scale. Nanolayering of CVD structures has also been demonstrated to improve surface replication as compared to the conventional, monolithic CVD material due to the elimination of columnar grain growth. This program will fabricate nanolayered CVD SiC materials and compare the microstructural and mechanical behavior of these materials to conventional CVD SiC. BENEFITS: Nanostructured ceramic materials IS an emerging class or materials that may b