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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decimal number system. The system of numbers using ten as its base. The digits in the decimal number system are 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. In a multidigit number, the position of the digit shows its value. Each position has a value ten times that of the position immediately to its right. For example, the number 5,286 is the same as 5,000 (5 . 1,000) + 200 (2 . 100) + 80(8 . 10) + 6 (6 . 1). decimal point. A dot which separates a whole number from its decimal fraction. In the United States, the decimal point is placed at the bottom of the number, as in 14.2. In European countries, the dot for the decimal point is raised to the center of the number, as in 14.2. decision altitude/decision height (ICAO). A specified altitude or height (A/H) in the precision approach at which a missed approach must be initiated if the required visual reference to continue the approach has not been established. decision height (DH) (aircraft operation). 14 CFR Part 1: “The height at which a decision must be made, during an ILS or PAR instrument approach, to either continue the approach or to execute a missed approach.” declination (navigation). The error in the indication of a magnetic compass caused by the magnetic north pole not being at the same location as the geographic north pole. In aerial navigation, declination is called variation. See variation. decoder (radar). The device used to decipher signals received from air traffic radar beacon transponders and display them as select codes. decompose. To separate into basic components, or elements. When electric current passes through water (a chemical compound), the water decomposes into its two chemical elements, hydrogen and oxygen. decontamination. The process of removing contamination from a body or a mechanism. Radiological decontamination is the process of removing or neutralizing radioactive contaminants from a person or a structure. decouple. To disconnect two components that are joined together, or to isolate one electrical circuit from another. dedicated computer. A small digital computer, often built into an instrument or control device, that contains a built-in program to perform a specific function. A digital autopilot is a dedicated computer to control an aircraft. It does not perform any other function. de-energize. To disconnect an object from its source of power. deep cycling (nickel-cadmium battery servicing). A maintenance procedure used with nickel-cadmium batteries to equalize all the cells. The battery is completely discharged, all of the cells are shorted, and the battery is allowed to stand in its shorted condition for a specified period of time. Then, the battery is recharged to 140% of its ampere hour capacity. deep discharge (batteries). A maintenance procedure for discharging a battery that removes all the electrical energy from the battery before it is recharged. When a battery is deep discharged, it is discharged at a specified rate until its voltage is down to a certain value, and then all the terminals of all the cells are connected with shorting straps and left shorted for a specified period of time. |
