时间：2011-03-11 23:13来源：蓝天飞行翻译 作者：admin 点击：次
|
lubricant. A natural or synthetic material used to reduce the friction between parts in sliding contact with each other. Even parts that seem to be smooth actually have microscopically rough surfaces. When one rough surface slides over another, the surfaces lock and oppose the movement (this is called friction). A lubricant between the surfaces holds them apart, and they slide over a film of the lubricant, rather than over each other. Lubricants may be in the form of a dry powder (powdered graphite or molybdenum), a liquid (oil), or a semi-liquid (grease). Lucite. The registered trade name for a transparent acrylic resin. Lucite is a thermoplastic resin, used for windshields and side windows of some aircraft. luminance. The amount of light emitted or scattered by a surface. Luminance is measured in lamberts. luminescence. The production of light by some method other than incandescence (light emitted because of high temperature). Luminescence may be caused by friction, chemical action, or electrical charges, and regardless of the method of luminescence, the light produces little or no heat. luminous paint. A type of paint having components that cause it to emit light, or glow in the dark. Radium was, at one time, the main component in luminous paint. But because of its harmful characteristics, it has been replaced by other materials. Luminous paint is used on instrument dials and pointers to make them visible in the dark. lutetium. A silvery-white, rare-earth chemical element. Lutetium’s symbol is Lu, its atomic number is 71, and its atomic weight is 174.97. Lutetium is the heaviest of the rare-earth elements and is used in nuclear technology. lye. A strong alkaline solution made of potassium hydroxide or sodium hydroxide. M MAA (maximum authorized altitude). A published altitude representing the maximum usable altitude or flight level for an airspace structure or route segment. MAA is the highest altitude on a Federal airway, jet route, area navigation low or high route, or other direct route for which an MEA is designated in 14 CFR Part 95, at which adequate reception of navigation aid signals is assured. MAC (mean aerodynamic chord). The chord of an imaginary airfoil that has the same aerodynamic characteristics as the actual airfoil. The length of the MAC is given for many aircraft, and the CG is expressed in percent of the mean aerodynamic chord (% MAC). Mach cone. The cone-shaped shock wave produced by a sharp-pointed object moving through the atmosphere at a speed greater than the speed of sound. machine language (computer operation). A language, made up of zeros and ones, that is usable by a digital computer. Machine language is difficult to write into a computer, so compilers and assemblers are used. A compiler is a special program that converts a high-level language that is easy for a programmer to use, into machine language that can be used by the computer. An assembler converts assembly language programs into machine language the computer can use. |
