时间：2011-03-11 23:11来源：蓝天飞行翻译 作者：admin 点击：次
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denatured alcohol. Ethyl, or grain, alcohol that has been treated with some type of additive to make it unfit for humans to drink. denier. A measure of the fineness of the yarns in a fabric. denim. A tough, heavy-duty fabric used for making work clothing. Denim is woven with colored threads for the warp (the threads that run the length of the fabric) and white threads for the fill (the threads that run across the fabric). denominate number. A number that has a unit of measurement with it. Three inches, six minutes, and 360 degrees are all denominate numbers. denominator (mathematical term). The part of a common fraction below the line. The denominator shows the number of parts the whole unit is divided into. In the common fraction 9/16, the denominator is 16. The whole unit is divided into 16 equal parts, and this fraction uses only nine of them. density. A measure of the amount of mass in a unit volume. An example is the amount of mass in a cubic foot, cubic inch, or cubic centimeter. Density is usually expressed in such units as pounds per cubic foot or grams per cubic centimeter. density altitude. The altitude in standard air at which the density is the same as that of the existing air. Density altitude is found by using a computer or chart to correct pressure altitude for nonstandard air temperature. Density altitude is used for computing the performance of an aircraft and its engines. density ratio (σ). The ratio of the density of the air at a given altitude to the density of the air at sea level under standard conditions. dent. A depression (usually smooth) in the surface of a material caused by the part being struck or pressed on by some outside object. A dent, unlike a gouge, removes none of the material. departure center (air traffic control). The ARTCC having jurisdiction for the airspace that generates a flight to the impacted airport. departure control (air traffic control). The function of an approach control facility that provides air traffic control service for departing IFR and, under certain conditions, VFR aircraft. departure sequencing program (air traffic control). A program designed to assist in achieving a specified interval over a common point for departures. depletion area (semiconductor term). The area on either side of the junction in a semiconductor device in which the majority carriers have been pulled away and ionic charges left. When the junction is forward-biased, the depletion area is very small. But when the junction is reverse-biased, the depletion area is large. depolarization (electrochemical cell condition). Removal of the hydrogen gas which forms on the positive material inside an electrochemical cell by absorbing it into one of the materials mixed with the electrolyte. |
