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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coefficient of friction. A dimensionless number used to show the ratio of the amount of force needed to move a body parallel to the surface on which it is resting to the amount of force needed to move the body perpendicular to the surface. coefficient of lift (aerodynamic parameter). A dimensionless number relating the amount of aerodynamic lift produced by an airfoil to its angle of attack. coefficient of linear expansion. A number relating the change in the length of an object to the change in its temperature. The coefficient of linear expansion is expressed in such terms as fractions of an inch per degree Celsius. coercive force (magnetism). A magnetic force used to remove magnetism from a magnetized object. The polarity of a coercive force is opposite to that which magnetized the object. cog belt. A flexible belt used to drive one shaft from another. The inside of the belt is crossed with a series of teeth which mate with teeth around the outside of the drive and driven wheels. A cog belt is used for timing and for transmitting force where there must be no slippage. coherent light. Light made up of a single frequency of electromagnetic radiation. cohesion. A force which causes a material to stick to itself. Cohesion differs from adhesion, which is a force that causes a material to stick to some other material. coil (electrical component). A device made of several turns of wire wound around a core. A coil is used to add inductance to an electrical circuit. coil form. The spool or tubing over which an electrical coil is wound. coil spring. A spring made of hardened steel wire wound in the form of a spiral. Coil springs may be used to apply force or to absorb shock or vibration. Short, open coil springs are used to cushion compressive loads, and tightly wound coil springs are used to absorb tensile loads. Coil springs can be used to measure force because their deflection is directly proportional to the applied force. coin dimpling (sheet metalworking). A process of preparing holes in sheet metal to receive flush rivets. The metal in the area to be dimpled is heated, and a coining die is pressed into it. The pressure of the die in the softened metal gives the dimpled hole sharp edges that provide a good fit for the countersunk rivet heads. coke (lubricating oil contaminant). A solid carbon residue left when all the volatile parts of a mineral oil have been removed by heat. Coke in an engine is a contaminant, and it must be removed. coking (lubrication system problem). A buildup of coke in the lubrication system of either a reciprocating engine or a gas turbine engine. If the engine is shut down before it has had time to cool properly, oil trapped in some of the hot locations will get so hot it will decompose into a hard, solid carbon deposit, coke. cold. A relative condition that indicates the lack of heat energy. cold bending (sheet metalworking). A method of working sheet metal in which the metal is bent without heating it. |
