Abstract: A method to form a sealed, partially or fully densified fiber reinforced composite preform which comprises: impregnating said preform with a major portion of a liquid, ceramic-forming precursor; initiating cure of the outer surface of said precursor with radiation, such as actinic radiation; a thereby forming a sealing barrier or skin on the surface of said preform. In a second embodiment the preform is infiltrated with a thermoplastic as liquid, frozen, excess frozen infiltrate optionally removed from the preform surface, then the preform is coated with a liquid which is curable with radiation, cure is initiated with radiation and the preform is sealed with a barrier coat.

Abstract: An electron gun for a high resolution color display tube comprises three inline cathode assemblies, a control grid with three inline apertures, a screen grid with three inline apertures, a screen grid slot plate with three inline substantially rectangular slots each associated with a different one of the apertures in the screen grid, and a main electron lens. The screen grid slot plate is attached to the screen grid on the side thereof facing the main electron lens. Each of the cathode assemblies produces an electron beam having a given beam current. Each of the slots in the screen grid slot plate has an inline dimension and a transverse dimension which are selected for the given beam current to independently control the horizontal and vertical sizes of the spot produced by each of the electron beams at a distance from the electron gun.

Abstract: A television raster centering aid comprises means for blanking a horizontal scan line located at the center of the vertical deflection field. In an illustrative embodiment, an operational amplifier is used to indicate the presence of the deflection field center based on the polarity of the current in the vertical deflection windings. A gating circuit receives information from the operational amplifier and from a source of horizontal synchronizing pulses. The gating circuit then generates a signal which is used to blank a horizontal scan line located at the vertical deflection center. In one embodiment the raster centering aid is used in a yoke adjustment machine for blanking a scan line in a flat-field video display.

Abstract: A set of auxiliary deflection coils are placed on opposite sides of a multibeam color television picture tube having a deflection yoke and color purity adjustment apparatus. The tube is operated to cause a raster to be scanned. The auxiliary coils are energized to cause the beams to be deflected to the left from their normal beam landing sites by a predetermined amount during at least one vertical field and to the right for the nominal beam sites by a predetermined amount during at least one vertical field in order to simulate beam landing errors caused by factors present in the television tube use environment. Color purity is then adjusted in the presence of the simulated beam landing errors.

Abstract: In a color television display system in which a plurality of horizontal in-line electron beams are directed toward color phosphor elements of a color picture tube, substantial convergence of the beams at all points on a scanned raster is achieved by transversely positioning the deflection yoke relative to the picture tube while maintaining substantial parallelism between the central longitudinal axes of the yoke and picture tube.