Abstract: Crystals formed of a solid-solution of NiSiF.sub.6 6H.sub.2 O provide very good materials for filtering ultraviolet light and will not deteriorate in temperatures as high as 115.degree. C. They are particularly useful in sensing devices which seek to identify the presence of ultraviolet light in the UV missile warning band.

Abstract: Crystals formed of a solid-solution of K.sub.2 Ni(SO.sub.4).sub.2 6H.sub.2 O provide very good materials for filtering ultraviolet light and will not deteriorate in temperatures as high as 110.degree. C. They are particularly useful in sensing devices which seek to identify the presence of ultraviolet light in the UV missile warning band.

Abstract: Crystals formed of a solid-solution of Ni(BF.sub.4).sub.2 6H.sub.2 O provide very good materials for filtering ultraviolet light and will not deteriorate in temperatures as high as 110.degree. C. They are particularly useful in sensing devices which seek to identify the presence of ultraviolet light in the UV missile warning band.

Abstract: This invention discloses a method of synthesizing a Group III-V compound semi-conducting film from a Group III metal alkyl and Group V hydride wherein the method comprises providing a vacuum chamber in which the synthesis takes place, adsorbing at least one monolayer of said Group III metal alkyl on an inert surface, backfilling the chamber with a Group V hydride, adsorbing the Group V hydride on the inert surface, providing atomic hydrogen atoms from electron-induced dissociation of Group V hydride adsorbed on the surface, inducing an electron-induced depletion of carbon at a rate which is dependent on the pressure of the Groups V hydride, retaining substantially all Group III metal on the surface and providing a thermally stable Group III-V compound semi-conducting film on the inert SiO.sub.2 surface. Methods for synthesizing a multilayer Group III-V semi-conducting film and specifically a GaN film are also disclosed, along with the apparatus for the synthesis of Group III-V compound semi-conducting films.

Abstract: The concentrations of residual heavy metal contaminants in the particulate material in a slurry produced in a particulate material washing process are monitored on-line and can be used to control the washing process. In alternative embodiments of the invention, x-rays, thermal neutrons or laser beams are directed at the slurry as it flows through a flow cell to induce emission of secondary x-rays, gamma rays or light, respectively, characteristic of the heavy metal contaminants and constituents representative of the solids contents of the slurry. These characteristic energies are measured and used to determine the concentration in ppm of the residual heavy metal contaminants in the particulate material within the slurry.

Abstract: The concentrations of residual heavy metal contaminants in the particulate material in a slurry produced in a particulate material washing process are monitored on-line and can be used to control the washing process. In alternative embodiments of the invention, x-rays, thermal neutrons or laser beams are directed at the slurry as it flows through a flow cell to induce emission of secondary x-rays, gamma rays or light, respectively, characteristic of the heavy metal contaminants and constituents representative of the solids contents of the slurry. These characteristic energies are measured and used to determine the concentration in ppm of the residual heavy metal contaminants in the particulate material within the slurry.