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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If the frequency of the sine wave signal applied to the vertical input is two times that of the signal applied to the horizontal plates, the Lissajous figure will be shaped like a figure eight (8). liter. A metric unit of volume. One liter is the volume of one kilogram of pure water at a temperature of 4°C under standard atmospheric conditions. One liter is equal to 1,000 cubic centimeters, and it is the same as 1.0567 quarts in the English system of measurement. lithium. A soft, silvery, highly reactive, alkali-metal chemical element. Lithium’s symbol is Li, its atomic number is 3, and its atomic weight is 6.939. Lithium is the lightest of the metals, and it is used as an ingredient in batteries and as an alloying agent for other metals. lithium cell (primary electrical cell). A lightweight, high-energy primary electrical cell, useful because of its long shelf life. A lithium cell uses lithium metal as its negative electrode and a gas dissolved in an electrolyte as its positive electrode. Lithium cells produce an open-circuit voltage of between 2.8 and 3.6 volts, which is about twice the open-circuit voltage of most other primary cells. lithium grease. A semisolid lubricant made of lithium salts and fatty acids. Lithium grease is highly water resistant and is useful for low-temperature lubricating applications. lithometeor (meteorology). The general term for dry particles suspended in the atmosphere. Lithometeors include dust, haze, smoke, and sand. lithosphere. The outer crust of the earth. The lithosphere is made mostly of rock and is considered to extend down for about 50 miles. litmus. A water-soluble powder that changes its color when acted on by an acid or a base (alkali). Litmus turns red when it is acted on by an acid and blue when acted on by a base. litmus paper. An indicator paper, used to determine whether a solution is acidic or basic (alkaline). Litmus paper is made by soaking a piece of absorbent paper in a solution of litmus powder dissolved in water. When blue litmus paper is wet with an acid solution, it turns red, and when red litmus paper is wet with an alkaline solution, it turns blue. Litzendraht wire (litz wire). A special type of conductor, used for carrying high-frequency alternating current. Litz wire is made of fine strands of insulated wire, woven together in such a way that any individual strand occupies, at some time, every position in the cross section of the conductor. This special type of construction gives litz wire its low opposition to the flow of high-frequency AC. live center (machine tool component). A sharp-pointed center that fits into the headstock of a lathe and turns with it. The material to be turned is mounted between the live center and the dead center and is turned by a lathe dog that clamps the material and turns with the faceplate. load (electrical). A device that uses electrical power. A load converts electrical energy into some other form of energy: mechanical, heat, light, or chemical. |
