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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silicone. A group of semi-inorganic polymers that have good thermal stability, are chemically inert, water repellent, and are good lubricants. Silicone products are available as liquids, solids, and semisolids. They are used in the manufacture of adhesives, lubricants, sealants, and electrical insulators. silicone rubber. An elastomeric material made from silicone elastomers. Silicone rubber is compatible with fluids which attack other natural or synthetic rubbers. silicon glaze (spark plug contaminant). A form of contamination on aircraft spark plugs that can lead to engine failure. Silica is found in sand and dust, and if a carburetor air filter leaks and allows sand or dust to get into the engine, the silica can form a hard, glass-like deposit on the nose core insulators of the spark plugs. Silicon glaze is an insulator at low temperatures, and will not cause a spark plug to show up as bad on a tester. But when the spark plug gets hot, the silicon glaze becomes conductive, and short-circuits the high voltage to ground before it builds up high enough to jump the gap between the electrodes. silicon solar cell. A special type of semiconductor device made of P-type silicon doped with boron and N-type silicon doped with arsenic. When light strikes the PN junction, electrons flow through the load circuit from the N-silicon to the P-silicon. silicon steel. An alloy steel that contains between 0.5% and 4.5% silicon. Silicon steel in sheet form is used for laminations to make up the core of electrical transformers. silver. A lustrous white, ductile, malleable, metallic chemical element. Silver’s symbol is Ag, its atomic number is 47, and its atomic weight is 107.870. Silver has the highest thermal and electrical conductivity of any metal, and it is used in electrical contacts and printed circuits. One of the primary industrial uses of silver is in photography. silver brazing. A form of brazing in which the filler metal is a silver-base alloy. See brazing. silvered-mica capacitor. A high-voltage capacitor that uses thin sheets of mica as the dielectric. Both sides of the mica are electrolytically coated with silver. This silver forms the plates of the capacitor. silver solder. An alloy of copper, silver, and zinc. The melting point of silver solder is lower than that of silver, but higher than that of lead-tin solder (soft solder). simple flap (airplane flap). A type of wing flap installed on some of the smaller airplanes. A portion of the trailing edge of the wing inboard of the ailerons can be folded downward in flight to increase the camber of the wing. This increases both the lift and the drag the wing produces. See plain flap. simple fraction (mathematics). A mathematical fraction with whole numbers for both its numerator and its denominator. An example of a simple fraction is 3/4. Fractions that are not simple fractions are called complex fractions. An example of a complex fraction is: 1/2 / 3/4. |
