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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microfilm. A photographic method of record storage in which the information to be stored is photographed, one page at a time, on a long roll of 35-millimeter film. The film, called microfilm, is put into a reader which projects the image on the back of a translucent screen that looks much like a television screen. The image of the page shows up in a size that is larger than the original page. microinches rms. A measure used for cylinder wall surface roughness. One microinch is equal to one millionth of an inch (0.000 001 inch). If a cylinder wall is required to have a roughness of 20 microinches rms (20 μin rms), the highest and lowest deviation from the average surface is 20 millionths of an inch. Micro-Mesh. A patented graduated series of cloth-backed cushioned sheets which contain abrasive crystals. Micro-Mesh is used for polishing and restoring transparency to acrylic plastic windows and windshields. micrometer (unit of length). A unit of length equal to one millionth of a meter. A micrometer is also called a micron. micrometer caliper. A precision measuring instrument in which the spindle moves in and out a specific amount for each revolution of the thimble. The amount the thimble turns, as shown on a scale engraved on the thimble, determines the amount the spindle moves. Micrometer calipers are built into instruments used to measure outside and inside dimensions and the depth of grooves. micrometer-setting torque wrench (precision hand tool). A type of hand-operated torque wrench in which the wrench handle snaps when the preset torque on the wrench drive is reached. The preset value of torque is determined by the compression of a spring in the wrench handle, and this compression is adjusted by screwing the handle onto the wrench body. The body and handle are marked in the same way as the spindle and thimble of a micrometer caliper. micro-microfarad. A unit of capacitance equal to one millionth of a millionth (1 x 10-12) of a farad. The term micro-microfarads has been changed to picofarads. micron (linear measurement). A unit of linear measurement equal to one millionth of a meter (0.000 001 or 1 x 10-6 meter), one thousandth of a millimeter, or 0.000 039 inch. A micron is also called a micrometer (micro meter). micron (pressure measurement). The amount of pressure exerted by a column of mercury one micrometer (one millionth of a meter) high, under standard conditions. One micron of pressure is equal to 0.001 millimeter of mercury (1 x 10-6 meter of mercury) at 0°C. micron (filter specification). A unit used to measure the effectiveness of a hydraulic filter and to identify the size of particles that are trapped by filters. One micron is a micrometer, or one millionth of a meter. It is 0.000 039 inch. Micronic filter. The registered trade name for a type of fluid filter whose filtering element is a specially treated cellulose paper formed into vertical convolutions, or wrinkles. Micronic filters prevent the passage of solids larger than about 10 microns, and they are normally replaced with new filters rather than being cleaned. |
