时间:2011-03-11 23:13来源:蓝天飞行翻译 作者:admin 点击:次
emergency (air traffic control). A distress or an urgency condition. emery paper. An abrasive paper made by bonding a layer of emery dust (pulverized corundum or aluminum oxide) to one side of a sheet of flexible paper. Emery paper is used to polish or clean metal surfaces. emery wheel. An abrasive wheel made by molding a mixture of emery (pulverized corundum or aluminum oxide) and a suitable binder into the form of a wheel. Emery wheels mounted on an arbor and turned by an electric motor can be used to grind metal and shape or sharpen steel tools. EMF (electromotive force). The force that causes electrons to move from one atom to another within an electrical circuit. An EMF is the difference in the electrical pressure, or potential, that exists between two points, and can be produced by converting mechanical, chemical, light, or heat energy into electrical energy. The basic unit of electromotive force is the volt. EMI (electromagnetic interference). Interference of radio reception by the radiation of electromagnetic energy from a piece of electronic equipment, or from conductors carrying high-frequency alternating current. emitter (bipolar transistor component). The electrode in a bipolar transistor (PNP or NPN transistor) that compares with the cathode in an electron tube. In the symbol for a bipolar transistor, the emitter is the electrode with the arrowhead. empennage (airplane structure). The tail section of an airplane. The empennage stabilizes the airplane in flight and causes it to rotate about its vertical and lateral axes. |