Westinghouse Electric

About: Westinghouse Electric is a company organization based out in Cranberry Township, Pennsylvania, United States. It is known for research contribution in the topics: Brake & Signal. The organization has 27959 authors who have published 38036 publications receiving 523387 citations.

The preparation and C-V characteristics of SiSi3N4 and SiSiO2Si3N4 structures

Abstract: Amorphous silicon nitride films have been deposited on silicon substrates, with main faces of {111} and {100} orientations, at 800–1100°C using the nitridation of silane with ammonia. In many cases, the substrate surfaces were etched in situ with mixtures of hydrogen-hydrogen chloride, hydrogen-water, or hydrogen-oxygen prior to the deposition of silicon nitride. In several instances, epitaxial silicon of good structural perfection was deposited on silicon substrates before the deposition process. Irrespective of the substrate surface treatments and other deposition conditions, the charge distribution of AlSiSi 3 N 4 structures was found to be unstable under large voltage bias at room temperature. This charge instability appears to be due to tunneling and trapping of carriers in the vicinity of the silicon-silicon nitride interface, and is concluded to be a basic property of the SiSi 3 N 4 structure prepared by the chemical deposition technique. The use of a thin silicon dioxide interlayer between the silicon nitride and the silicon has been found to suppress the charge instability in MNS structures; MNOS structures are stable over wide ranges of electrical and thermal stress.

Automated visual assessment system with steady state visual evoked potential simulator and product detector

Abstract: An automated visual testing system is disclosed which presents an alternating steady state visual stimulus to a patient through an optical system that modifies the stimulus image. As the image changes, the patient produces evoked potentials that change. The evoked potentials are detected by a product detector which produces the amplitude of the evoked potentials. The amplitude is monitored through an analog to digital converter by a supervisor computer. The supervisor computer produces patient response curves from which it diagnoses visual system malfunction and/or prescribes correction. A control processor controls a stimulus generator to produce the image and an optical system, that includes polarizers, an astigmatism test slit or a cylindrical lense, a zoom lense system and a variable focal length test lense, transmits the image to the patient. The steady state visual potential stimulus generator is a device by which a rapidly complementing or flashing pattern can be presented to the patient. The generator allows the contrast of the image to be varied without varying luminance and allows operation in a true bicolor and multicolor mode. The product detector detects the level of the steady state evoked potential signals even in the presence of substantial background noise and extraneous electroencephalographic signals. These detectors can be used to monitor the evoked potential produced by visual, all or somatic steady state stimuli. The components described above can be used to produce a system that can determine to which of several different displays an observer is paying attention by providing images that blink at different frequencies and product detectors for each of the stimulus frequencies. The product detector producing the highest output indicates the display upon which the observer is focused.

Automatic touch screen calibration method

Abstract: A method for automatically calibrating a touch screen used in conjunction with a graphic display is executed prior to every interactive session. Three points, defining perpendicular axes, are displayed and an operator is instructed to touch the touch screen at each of the points in succession. Coordinates for the three points output by the touch screen are checked for reasonableness and perpendicularity. If these checks are passed, a coordinate translation matrix is generated for converting touch screen coordinates into display coordinates.

Effect of Surface Preparation on Intergranular Stress Corrosion Cracking of Alloy 600 in Hydrogenated Steam

Abstract: In the literature it is a common belief that electropolishing mitigates primary water stress corrosion cracking (PWSCC) because it removes superficial cold work. Here, it is shown that electropolished Alloy 600 (UNS N06600) exposed to hydrogenated steam undergoes internal Cr oxidation, whereas mechanical polishing induces external oxidation. This has implications for SCC initiation, which has been tested with different surface preparations (electropolishing and mechanical polishing) using reverse-U-bend (RUB) and C-ring samples. The results show a systematic trend that mechanically polished surfaces are more resistant to stress corrosion cracking (SCC) than electropolished surfaces. The mechanism involved in this increased resistance is thought to be related to short-circuit diffusion of Cr to the surface, which promotes external rather than internal oxidation. The role of compressive stress induced by mechanical polishing is a less-likely explanation of the observed effects. Mechanical polishing...

Production of Fast Switching Power Thyristors by Proton Irradiation

Abstract: There are several techniques currently employed by various manufacturers in the fabrication of fast switching power thyristors. Gold doping and irradiation by electron beams are among the more common ones. In all cases, the fast switching capability results from a reduction of the minority carrier lifetime of the host material by the introduction of carrier traps or recombination centers. However, accompanying this beneficial reduction in switching speed is a deleterious increase in forward voltage drop which also results from the introduction of carrier traps. Methods which minimize the voltage drop increase as the switching speed is reduced are highly desirable. One such method would achieve this by introducing the traps or recombination centers into well defined narrow regions where they will be more effective in reducing the switching speed than in increasing the forward voltage drop. Because the proton range-energy relationship in materials is relatively well defined and the lifetime reducing displacements occur near the end of their ranges, the lifetime in silicon can be reduced where desired by the precise control of proton energy. Dual energy proton beams from a tandem Van de Graaff accelerator were used in the experiments to determine whether proton beam irradiations offer advantages over other techniques. This was the subject of the present work. The results indicate that this is the preferred technique for reproducibly and rapidly processing fast switching thyristors with superior characteristics. The experimental procedure is discussed and comparisons are made with electron and neutron irradiated thyristors.