时间：2011-03-11 23:18来源：蓝天飞行翻译 作者：航空 点击：次
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Vacuum-tube voltmeters (VTVM) are being replaced with solid-state field-effect transistor (FET) voltmeters. vulcanize. A method of treating crude rubber with heat to give it such useful properties as elasticity, strength, and chemical and dimensional stability. W wafer (semiconductor production). A thin slice of silicon or germanium used as the substrate on which the components of an integrated circuit chip are formed. A wafer is also called a slice. wafer-type selector switch (electrical component). A multicontact switch with the contacts arranged around the outside of a circular wafer. A shaft through the center of the wafer is rotated by a knob to connect a center contact, or wiper, to any one of the contacts around the wafer. Several wafers can be stacked together with their center contacts rotated by the same shaft. waffle piston (reciprocating engine component). A reciprocating engine piston with fins cast or forged on the bottom of the head, inside the piston. The fins cross to form a pattern that looks much like the surface of a waffle. The fins strengthen the piston head and provide extra surface area to increase the amount of heat the oil can carry away from the piston. wake. The high-velocity stream of turbulent air behind an operating aircraft engine. wake turbulence (aircraft operation). The disturbed air left behind an airplane. At one time, it was thought that the rough air behind and below an airplane in flight was caused by the propeller slipstream. But this turbulence is actually caused by air spilling over the wing tips and forming tornado-like vortices. Wake turbulence also includes thrust stream turbulence, jet blast, jet wash, propeller wash, and rotor wash, both on the ground and in the air. walk-around bottle (oxygen bottle). A small steel cylinder containing aviators breathing oxygen. The walk-around bottle is fastened to the flight suit and attached to the oxygen mask to supply the aviator with oxygen as he or she walks around the aircraft. When the aviator is at his or her regular duty station, the walk-around bottle is disconnected, and the oxygen mask is plugged into the built-in oxygen system. wall cloud (meteorology). The well-defined bank of vertically developed clouds having a wall-like appearance and which form the outer boundary of the eye of a well-developed tropical cyclone. Wankel engine. A form of rotary, internal combustion engine. Instead of using cylinders and moving pistons, the Wankel engine uses a rounded, triangular-shaped rotor, with sliding seals that form the combustion space inside an oblong circular chamber. Expanding gases from the burning fuel-air mixture press against the rotor and rotate it and the drive shaft geared to it. warm. A term used to identify a relative condition of temperature; it is opposed to cool. A warm wind is a movement of air whose temperature is slightly higher than the temperature of the person upon whom it is blowing. warm front (meteorology). The surface between two air masses in which a mass of warm air is flowing over a mass of colder air. Warm fronts usually bring low ceilings, fog, and light but steady rain. |
