Abstract: An environmental wind tunnel for producing air flow over an automotive vehicle includes a source of air under pressure and an elongated housing for receiving an automotive vehicle. The environmental wind tunnel has an upstream end coupled to the downstream end of the source of air under pressure, so that air is blown axially through the housing from its upstream end to its downstream end. The environmental wind tunnel also includes a large area ratio contraction with large area corner sections, large area duct work with a low angle diffuser, a large area fan, and acoustic treatments on the turning vanes, test chamber walls, and corner duct interior surfaces. In addition, in-flow acoustic absorption panels, and one or more flow conditioning screens may also be included in the environmental wind tunnel.

Abstract: A method of enhancing the specific contact resistivity in InP semiconductor devices and improved devices produced thereby are disclosed. Low resistivity values are obtained by using gold ohmic contacts that contain small amounts of gallium or indium and by depositing a thin gold phosphide interlayer between the surface of the InP device and the ohmic contact. When both the thin interlayer and the gold-gallium or gold-indium contact metallizations are used, ultra low specific contact resistivities are achieved. Thermal stability with good contact resistivity is achieved by depositing a layer of refractory metal over the gold phosphide interlayer.

Abstract: Low angle V-grooves are provided in the target surfaces of optoelectronic or photovoltaic devices such as solar cells and photodetectors. The low angle V-grooves increase the efficiency of the devices by promoting total internal reflection of light reflected from the target surface at the interface of the coverglass and the external environment.

Abstract: A dynamic strain measurement circuit includes a constant resistance conditioner. The constant resistance conditioner compensates for changes in lead wire resistance due to temperature. The conditioner includes adjustable resistance connected between a voltage supply and the strain gage. A potential difference is detected in the circuit and compared to a reference potential. Differences between the reference potential and the detected potential produce an error signal which is used to drive the control of the resistance value of the adjustable resistance in the measurement circuit.

Abstract: This application concerns a simple passive circuit that improves current balance in paralleled power MOSFETs that are not precisely matched and that are operated in their active region from a common gate drive. A nonlinear circuit consisting of diodes and resistors generates a differential gate potential required to correct for unbalance while maintaining low losses over a range of current.

Abstract: An environmental wind tunnel facility for automotive vehicles, such as passenger cars, is provided with a slotted-wall extension which improves the air flow simulation over the entire vehicle and enables a reduction in the physical size of the environmental wind tunnel.

Abstract: A niobium-aluminum base alloy having improved oxidation resistance at high temperatures and consisting essentially of 48%-52% niobium, 36%-42% aluminum, 4%-10% chromium, 0%-2%, more preferably 1%-2%, silicon and/or tungsten with tungsten being preferred, and 0.1%-2.0% of a rare earth selected from the group consisting of yttrium, ytterbium and erbium. Parabolic oxidation rates, k.sub.p, at 1200.degree. C. range from about 0.006 to 0.032 (mg/cm.sup.2).sup.2 /hr. The new alloys also exhibit excellent cyclic oxidation resistance.