时间：2011-03-11 23:13来源：蓝天飞行翻译 作者：admin 点击：次
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gouge. A defect in the form of a groove or deep scratch in an otherwise smooth surface. governor. A control used to cause certain types of equipment to operate at a desired speed. A governor has a sensor to measure the speed, a datum from which the speed is referenced, and a control to adjust the speed so it agrees with the datum. GPS (global positioning system). An electronic navigation system in which the position of the aircraft is determined by the angular relationship between the aircraft and a series of orbiting satellites. GPU (ground power unit). A piece of aircraft ground support equipment that includes a motor-generator and an air compressor. The GPU can be connected to an aircraft on the ground to supply electrical power and compressed air for system operation when the engines are not operating. grade-A cotton fabric (aircraft structural material). Cloth made of long-staple cotton, used to cover certain types of aircraft structures. Grade-A cotton fabric has between 80 and 84 threads per inch in both warp and fill, and new grade-A fabric has a minimum tensile strength of 80 pounds per inch. gradient (meteorology). A change in value per unit of a second parameter. Such terms as pressure gradient (inches of mercury per thousand feet) and temperature gradient (degrees Celsius per thousand feet) are commonly used in meteorology. grain (wood characteristic). The direction, size, and arrangement of the fibers in a piece of wood. grain boundary (metallurgy). The lines inside a piece of metal formed by the surfaces of the grains. Intergranular corrosion forms along the grain boundaries in metal that has been improperly heat-treated in such a way that the grains have become enlarged. The hardness of a metal is determined by the size of the grain. The smaller the grain, the harder the metal. gram. A unit of mass in the metric system. One gram is equal to 1/1000 of a kilogram or about 0.035 ounce and is the weight of one cubic centimeter of water at its maximum density. gram-centimeter (unit of work). A unit of work in the centimeter-gram-second gravitational system. One gram-centimeter is the amount of work done when a force of one gram causes a movement of one centimeter in the direction the force is applied. graphite. A soft, black form of carbon that normally has a greasy feel. Graphite, also known as black lead, is used as a dry lubricant and also as the “lead” in a pencil. Structural graphite is used in composite structure because of its strength and stiffness. graphite fibers. An advanced composite fiber made by drawing filaments of carbon at a high temperature and in a controlled atmosphere. Graphite fibers are very strong and stiff. gravitational acceleration. The acceleration (speeding up) of a freely falling object caused by the attraction of the mass of the earth. If an object is allowed to fall freely in a vacuum, it will accelerate at a rate of 32.2 feet per second, or 980.7 centimeters per second, each second it falls. |
