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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numbers. Terms used to assign a value or an order to something. Cardinal numbers, such as 1, 2, and 3, tell how many. They assign a value to something. One engine, 2 wrenches, 3 airplanes are examples of cardinal numbers being used to assign values. Ordinal numbers, such as first, second, and third, tell us the order in which something occurs. The first day, the second order, or the third time are examples of the use of ordinal numbers. numerator (mathematics). The part of a common fraction above the line; the denominator is the part of the fraction below the line. The numerator shows the number of parts of the denominator that are used. In the fraction 9/16, nine is the numerator. The whole unit is divided into 16 equal parts (the denominator), and we are using only nine of these parts. numerical control. A digital control system. Numerical control (digital control) is used with production machine tools to machine complex parts with more precision than can be done with an analog control system. numerical weather prediction (meteorology). Forecasting by digital computers solving mathematical equations. Numerical weather prediction is used extensively in weather services throughout the world. nut (threaded fastener). A small metal collar, usually having a hexagonal (six-sided) shape. The hole in the nut is threaded so that it can be screwed onto a bolt. Bolts and nuts are used to fasten two or more pieces of material together. The bolt is installed in holes drilled through the pieces, and a nut is screwed onto the bolt to clamp the pieces together. nutation. The slow back-and-forth rocking of the axis of a spinning body. A gyroscope, a spinning top, and even the earth, as it spins, have a slight nutation. nutplate (aircraft fastener). A special form of nut that can be riveted to an aircraft structure. Screws can be driven into a nutplate without having to hold the nutplate with a wrench. nylon. The name of a family of synthetic materials that are part of the polymer chain. Nylon is used for making cloth and rope and for such molded parts as wheels, gears, and pulleys. Nylon is strong, lightweight, and resistant to most chemicals. O OALT (operational acceptable level of traffic) (air traffic control). An air traffic activity level associated with the designed capacity for a sector or airport. The OALT considers dynamic changes in staffing, personnel experience levels, equipment outages, operational configurations, weather, traffic complexity, aircraft performance mixtures, transitioning flights, adjacent airspace, hand-off/point-out responsibilities, and other factors that may affect an air traffic operational position or system element. The OALT is normally considered to be the total number of aircraft that any traffic functional position can accommodate for a defined period of time under a given set of circumstances. oblique angle. An angle that is neither a right angle (a 90° angle) nor a straight line (a 180° angle). An oblique angle can be either an acute angle (an angle of less than 90°) or an obtuse angle (an angle of more than 90°). |
