Organized nanostructures are formed after irradiation of layers of randomly aligned single-wall carbon nanotube (SWNT)-polymer composites by a Ti:Sapphire 775 nm laser with a 150 fs pulse at fluences near 0.1 J/cm2. A...
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Biodegradable polymers with high mechanical strength, flexibility and optical transparency, optimal degradation properties and biocompatibility are critical to the success of tissue engineered devices and drug deliver...
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Recent advances in recombinant DNA technology have created the potential for engineering of protein molecules to specific uses beyond those normally considered for biomaterials. This research project has demonstrated ...
Recent advances in recombinant DNA technology have created the potential for engineering of protein molecules to specific uses beyond those normally considered for biomaterials. This research project has demonstrated the feasibility of producing polypeptides useful for narrow band filters and nonlinear optical applications. Synthetic genes, ranging in size from 36 to 576 base pairs, have been constructed from oligonucleotides using a restriction doubling technique. The synthetic genes have been inserted into a Protein A fusion expression system. Fused polypeptides from induced cells have been purified by affinity chromatography (IGG), and analyzed by polyacrylamide gel electrophoresis.
Step-graded InGaPySb1-y and InxGa 1-xAs metamorphic buffer layer (MBL) structures are grown on GaAs substrates by metal-organic chemical vapor deposition (MOCVD). AFM analysis indicates that graded group V InGaPySb1-y...
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A major limitation of the current technology for GaN epitaxy is the availability of suitable substrates matched in both lattice constant and thermal expansion coefficient. One alternative for the development of GaN su...
A major limitation of the current technology for GaN epitaxy is the availability of suitable substrates matched in both lattice constant and thermal expansion coefficient. One alternative for the development of GaN substrates rests in the application of halide vapor phase epitaxy (HVPE) to produce GaN films at high growth rates. In this paper, we describe the growth of thick GaN films via the HVPE technique on (0001) sapphire and (111) Si substrates. At a temperature of 1030°C, films are grown at rates between 70 and 90 μm/hr, yielding total thicknesses exceeding 200 μm on sapphire. DCXRD measurements of GaN/sapphire indicate FWHM values less than 220 arcsec on 180 μm thick films. Room temperature PL measurements of GaN/sapphire indicate strong emission at 3.41 eV, with a FWHM value of 65 meV. Moreover, no detectable deep level emission was found in room temperature PL measurement. Under optimized conditions, films are morphologically smooth and optically clear. The GaN morphology appears to be a strong function of the initial nucleation conditions, which in turn are strongly affected by the partial pressure of GaCl. HVPE growth on (111) Si substrates is accomplished using an AlN MOVPE buffer layer.
Organized nanostructures are formed after irradiation of layers of randomly aligned single-wall carbon nanotube (SWNT)-polymer composites by a Ti:Sapphire 775 nm laser with a 150 fs pulse at fluences near 0.1 J/cm2. A...
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Organized nanostructures are formed after irradiation of layers of randomly aligned single-wall carbon nanotube (SWNT)-polymer composites by a Ti:Sapphire 775 nm laser with a 150 fs pulse at fluences near 0.1 J/cm2. At varying peak fluences morphology is seen where the tubes are ejected from the substrate or formed into long, parallel structures of SWNT’s. These structures have been created on both glass substrates and carbon grids. Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) investigation of the structures reveal that they are composed of bundled nanotubes typically 400 nm – 1 micron long. Large-area laser patterning of the film allows for structuring of the film without detrimental decreases in conductivity.
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