時(shí)間：2011-03-11 23:11來(lái)源：藍(lán)天飛行翻譯 作者：admin 點(diǎn)擊：次
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abfarad. A basic unit of electrical capacitance in the electromagnetic-centimeter-gram-second system. One abfarad is equal to 109 farads in the absolute meter-kilogram-second-ampere system. The abbreviation for abfarad is aF. abhenry. A basic unit of electrical inductance in the electromagnetic-centimeter-gram-second system. One abhenry is equal to 10-9 henries in the absolute meter-kilogram-second-ampere system. The abbreviation for abhenry is aH. abmho. A basic unit of electrical conductance in the electromagnetic-centimeter-gram-second system. One abmho is equal to 109 mhos in the absolute meter-kilogram-second-ampere system. The abbreviation for abmho is (aΩ)-1. An abmho is also known as an absiemens, aS. abort. To terminate an operation prematurely when it is seen that the desired results will not be obtained. aborted start (gas turbine engine operation). Termination of the start procedures in a gas turbine engine when it is seen that normal combustion has not taken place within the prescribed time limits. aborted takeoff. A takeoff terminated prematurely when it is determined that some condition exists which makes takeoff or further flight dangerous. abradable seal (gas turbine engine component). A general term for a knife-edge seal inside a gas turbine engine that wears away (abrades) slightly to produce an extremely close fit between a rotating and a stationary part of the engine. abradable shroud (gas turbine engine component). A special shroud ring built into the outer turbine case of a gas turbine engine. The shroud fits tightly around the outside of the turbine wheel, which is equipped with special knife edges around its periphery. If the turbine blades creep (grow in length because of heat and high centrifugal loads), the knife edges will wear away the abradable shroud and do no damage. abradable strip (gas turbine engine component). A strip of material in the compressor housing of some axial-flow gas turbine engines. The tip of the compressor blade touches the abradable strip and actually wears, or abrades, a groove in it. This groove ensures that the blade operates with the minimum amount of tip clearance. abradable tip (compressor blade tip). The tip of some axial-flow compressor blades made in such a way that it will abrade, or wear away, when it contacts the compressor housing. The abradable tip wears away to allow the engine to have a minimum amount of tip clearance between the blade and the housing. abrade. To wear away a surface or a part by mechanical or chemical action. A rough surface may be made smooth by mechanically abrading it with sandpaper. Extremely smooth surfaces may be roughened enough for paint to adhere by rubbing the surface with abrasive paper or by chemically abrading it with an etching solution. abrasion. A form of damage to a surface made by roughening or wearing it away with scratches or gouges. Abrasion is often caused by foreign matter trapped between two surfaces having relative motion between them. |
