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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steam cooling. A method of liquid cooling a reciprocating engine in which the coolant, normally water, is allowed to absorb enough heat that it boils, or changes into steam. The steam gives up this heat when it condenses back into a liquid. steam fog (meteorology). Fog formed when cold air moves over relatively warm water or wet ground. steatite. A ceramic insulating material used in making insulators for high-voltage, high-frequency radio transmitters. Steatite is mainly a silicate of magnesium. steel. An alloy of iron that usually contains between 0.1% and 1.5% carbon with other elements. Iron is melted in a furnace, and air or oxygen is blown through it to combine with and get rid of the excess carbon. After sufficient carbon has been removed, the correct amounts of such alloying elements as manganese, molybdenum, chromium, nickel, vanadium, and tungsten are added. The steel is poured from the furnace into ingots, which are rolled or forged into the desired shape or form. steel wool. A mat of fine threads of steel. Steel wool is used as an abrasive to remove rust or to clean a surface. stellite. A nonferrous alloy of cobalt, chromium, and tungsten. Stellite is hard, wear- and corrosion-resistant, and does not soften until its temperature is extremely high. Stellite is welded to the face of many reciprocating engine exhaust valves that operate at very high temperatures. step (seaplane hull design). A break in the bottom of the hull of a flying boat or seaplane float. When a seaplane is taking off, it is rocked back and forth in the water as its speed increases until the float rides high enough for air to pass between the water and the step. Getting a seaplane up on the step decreases the friction of the water against the float. step-down transformer (electrical transformer). A type of electrical transformer with more turns in the primary winding than in the secondary. The secondary voltage of a step-down transformer is lower than the primary voltage, but the secondary current is greater than the primary current. stepped solvents (finishing material component). Solvents in a finishing material that have different rates of evaporation. A finishing material thinned with stepped solvents dries evenly and slowly, as the solvents evaporate out over a long period of time. stepping motor. A precision electric motor whose output shaft position is changed in steps by pulses from the control device. Stepping motors can make high-torque changes in small angular increments to their output shaft. stepping relay. A type of relay-operated multipole electrical switch. A relay moves the wiper, or selector, of the switch one step at a time, as pulses of electrical energy are sent into the relay coil. Stepping relays are used in rotary-dial telephone systems. step stud, stepped stud. A type of stud used to replace a stud that has stripped the threads in a cast housing. A stud is a type of threaded fastener used to fasten a component to a casting; for example, to fasten the cylinders of an aircraft engine to the crankcase. One end of the stud has coarse threads that screw into the soft metal of the casting. The other end has fine threads to accept a nut. |
