Abstract: A method of improving the photoluminescence of silicon nanoparticles is provided along with a description of the silicon nanoparticle compositions prepared therefrom. The method generally comprises exposing a composition comprising silicon nanoparticles having a mean particle diameter not greater than 5 nm and a fluid to a non-ambient condition selected from (i) elevated temperature, (ii) elevated humidity, (iii) elevated pressure exerted by an oxygen-containing gas, (iv) a hydrogen plasma, (v) hydrogen gas, (vi) ultraviolet radiation, and (vii) and a combination of at least two of (i)-(vi). Optionally, the silicon nanoparticles may be prepared by a gas phase reaction. The exposure of the silicon nanoparticle compositions to the non-ambient condition results in improved photoluminescence. In particular, the exposed nanoparticles exhibit increased maximum emission intensity and luminescent quantum efficiency.

Abstract: A method of improving the photoluminescence of silicon nanoparticles is provided along with a description of the silicon nanoparticle compositions prepared therefrom. The method generally comprises exposing a composition comprising silicon nanoparticles having a mean particle diameter not greater than 5 nm and a fluid to a non-ambient condition selected from (i) elevated temperature, (ii) elevated humidity, (iii) elevated pressure exerted by an oxygen-containing gas, (iv) a hydrogen plasma, (v) hydrogen gas, (vi) ultraviolet radiation, and (vii) and a combination of at least two of (i)-(vi). Optionally, the silicon nanoparticles may be prepared by a gas phase reaction. The exposure of the silicon nanoparticle compositions to the non-ambient condition results in improved photoluminescence. In particular, the exposed nanoparticles exhibit increased maximum emission intensity and luminescent quantum efficiency.

Abstract: A system for preparing nanoparticles is described. The system can include a reactor for producing a nanoparticle aerosol comprising nanoparticles in a gas. The system also includes a diffusion pump that has a chamber with an inlet and an outlet. The inlet of the chamber is in fluid communication with an outlet of the reactor. The diffusion pump also includes a reservoir in fluid communication with the chamber for supporting a diffusion pump fluid and a heater for vaporizing the diffusion pump fluid in the reservoir to a vapor. In addition, the diffusion pump has a jet assembly in fluid communication with the reservoir having a nozzle for discharging the vaporized diffusion pump fluid into the chamber. The system can further include a vacuum pump in fluid communication with the outlet of the chamber. A method of preparing nanoparticles is also provided.

Abstract: A silicone composition comprises a curable silicone composition and nanoparticles. The nanoparticles of the silicone composition are produced via a plasma process. A cured product formed from the silicone composition is also disclosed. The cured product includes the nanoparticles dispersed therein.

Abstract: The present invention provides a low-pressure very high frequency pulsed plasma reactor system for synthesis of nanoparticles. The system includes a chamber configured to receive at least one substrate and capable of being evacuated to a selected pressure. The system also includes a plasma source for generating a plasma from at least one precursor gas and a very high frequency radio frequency power source for providing continuous or pulsed radio frequency power to the plasma at a selected frequency. The frequency is selected based on a coupling efficiency between the pulsed radio frequency power and the plasma. Parameters of the VHF discharge and gas precursors are selected based on nanoparticle properties. The nanoparticle average size and particle size distribution are manipulated by controlling the residence time of the glow discharge (pulsing plasma) relative to the gas molecular residence time through the discharge and the mass flow rates of the nanoparticle precursor gas (or gases).

Abstract: A photonic crystal based optical modulator that is capable of being integrated with electronic circuits on a chip. An optical modulator is formed by using a substrate, an optical buffer layer, and optical waveguide layer and providing photonic crystal regions in the optical waveguide layer. Improved strength and durability of the optical modulator is achieved by using an electrode island to limit the suspended area to the minimum required by the photonic crystal waveguides.

Abstract: A Yagi antenna array is specifically designed for insertion in a thin wing leading edge radome. Tubular elements for driver, director components are inserted within the structural web of the radome and critical dimensions of antenna components, relative to wavelength, help achieve superior performance in the compact package.

Abstract: An MRI machine RF body coil is arranged so that it can also function as a hyperthermia treatment apparatus by arranging the RF body coil as an array of individual antenna element connected to each other by individually controllable switches and feedthrough elements.

Abstract: An antenna system includes a reflector grid which reflects signals which are within the operative frequency range of the antenna and passes received signals of higher frequency. An absorber is placed proximate to the reflector grid to absorb signals which are passed by the grid. A second reflector located proximate to the absorber reflects signals back through the absorber such that signals reflected by the antenna system are twice attenuated by the absorber.