[Corresponding to U.S. Patent No. 3,620,784] Zinc dust coatings which, when dried on a metal surface, are crack, craze, and abrasion resistant. The coatings are formed by combining a potassium silicate solution with zinc dust and, optionally, including an alkyl trialkoxysilane. These compositions of basically inorganic materials are intended primarily for the protection of metals subject to adverse environmental conditions. DEPOSITION OF FILMS NASA Case No. LAR-10362 Canada, France, Japan, Address inquiries to: Langley Station Hampton, VA 23665 [Corresponding U.S. Patent Application Pending] A system for depositing multilayer protective coatings on a glass or quartz substrate wherein a single heat source evaporates selective ones of a plurality of vaporizable metal coatings contained in the vacuum chamber with the substrate to be coated. The metal coating materials are contained in an electrically grounded crucible with an electrical potential of approximately 2000 volts being generated between the crucible and a cathode filament and wherein a magnetic field is provided perpendicular to the propagation direction of the electrons generated for bending the electron beam trajectory toward the coating metal contained in the crucible. Honeycomb cores formed of tubule sections bounded orthogonally by plane facings are described. The tubule sections are defined as being formed of minimal surface elements that orthogonally intersect all of the surfaces of a kaleidoscopic cell at least once. In other words, the tubule sections are broken into elements for definition purposes. The elements are defined as minimal surface elements, i.e., elements that have a mean curvature that is equal to zero at all points on their surface. These elements are further defined inside an imaginary kaleidoscopic cell in that they orthogonally intersect all surfaces of an imaginary kaleidoscopic cell at least once. The tubule sections are smoothly interconnected to form honeycomb core structures that have no internal discontinuities. Expandable space-frames formed of a plurality of hinge joint assemblies and struts are reported in this invention. The spaceframes are utilized in various types of structures. They can form a basic building structure or can be utilized in a planar manner to form the floors and walls of a structure. They can be utilized in space to define a structure such as a manned orbiting laboratory. ELECTRON MICROSCOPE APERTURE SYSTEM NASA Case No. ARC-10448-1 Canada, France, Japan, Germany, Address inquiries to: [Corresponding U.S. Patent-Application Pending] An electron microscope is described, which includes an electron source, a condenser lens having either a circular aperture for focusing a solid cone of electrons onto a specimen or an annular aperture for focusing a hollow cone of electrons onto the specimen, and an objective lens with an annular objective aperture, for focusing electrons passing through the specimen onto an image plane. The invention also entails a method of making the annular objective aperture, using electron imaging, electrolytic deposition, and ion etching techniques. |