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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NFDC (National Flight Data Center) A facility in Washington, D.C., established by the FAA to operate a central aeronautical information service for the collection, validation, and dissemination of aeronautical data in support of the activities of government, industry, and the aviation community. The information is published in the National Flight Data Digest. NFDD (National Flight Data Digest). A daily publication of flight information appropriate to aeronautical charts, aeronautical publications, Notices to Airmen, or other media serving the purpose of providing operational flight data essential to safe and efficient aircraft operations. nibble (data processing term). A grouping of four bits of digital data. Two nibbles form a byte (eight bits of digital data). nibbler. A sheet-metal-working tool. A nibbler uses a reciprocating punch to remove metal as it moves back and forth. The punch takes away only a small bite of metal each stroke. Nichrome. The registered trade name for an alloy of nickel and chromium. Nichrome wire, whose resistance is about 65 times that of copper, is used for making electrical heater elements and precision wire-wound resistors. nickel. A silvery, hard, ductile, magnetic, metallic chemical element. Nickel’s symbol is Ni, its atomic number is 28, and its atomic weight is 58.71. Nickel is used for plating, as an alloy in steel, and for making batteries. nickel-cadmium battery. A form of storage battery in which nickel hydroxide is the active element in the positive plates, and cadmium hydroxide is the active element in the negative plates. The electrolyte is potassium hydroxide and water. The cells of a nickel-cadmium battery have a closed-circuit voltage of approximately 1.25 volts, and they maintain this voltage until they are almost completely discharged. Nickel-cadmium batteries have a low internal resistance and are ideally suited for such high-current applications as starting gas turbine engines. nickel silver. An alloy of copper, zinc, and nickel. Nickel silver is also called German silver. night. 14 CFR Part 1: “The time between the end of evening civil twilight and the beginning of morning civil twilight, as published in the American Air Almanac, converted to local time.” nimbostratus (meteorology). A principal cloud type, gray colored and often dark. The appearance of nimbostratus clouds is often diffused by more or less continuously falling rain or snow, which in most cases reaches the ground. Nimbostratus clouds are normally thick enough to blot out the sun. niobium. A silvery, soft, ductile, metallic chemical element. Niobium’s symbol is Nb, its atomic number is 41, and its atomic weight is 92.906. Niobium is used as an alloying element for steel and as a metal used in superconductivity research. nipple (pipe fitting). A short piece of pipe, threaded on both ends. nitrate dope (aircraft finishing material). A finishing material whose film base is made of a cellulose material dissolved in nitric acid. Nitrate dope has good encapsulating properties, but it is being replaced by cellulose acetate butyrate (CAB) dope, because it is far more flammable than CAB dope. |
