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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multiplex (method of communications). Multiplex transmission is a method of two-way communications in which both stations can transmit at the same time on the same frequency or on the same line. Normal telephone communications is an example of multiplex communications. Both parties can talk on the same line at the same time. multiplicand (mathematics). The number in a multiplication problem that is multiplied by another number. In the problem 4 . 2 = 8, the number four is the multiplicand. multiplier (mathematics). The number in a multiplication problem that is used to multiply another number. In the problem 4 . 2 = 8, the number two is the multiplier. multiplier resistor. A resistor in series with a voltmeter mechanism used to extend the range of the basic meter or to allow a single meter to measure several ranges of voltage. multispar wing (aircraft structure). A type of airplane wing construction that uses several small spars extending along the span of the wing to carry the structural loads. Multiple small spars carry the load better and weigh less than the two larger spars used in many aircraft wings. multivibrator (electronic circuit). A type of oscillator in which there are two active devices (transistors or electron tubes) which alternate in conducting. Multivibrators may be free running, bistable, or monostable. A free-running multivibrator automatically switches back and forth between the devices and continues to do this as long as power is supplied. In a monostable multivibrator, one device is normally conducting, but a pulse on its base or grid will switch it off and the other one on. As soon as the pulse is removed, the conduction is switched back to the first. In a bistable multivibrator, either device conducts equally well. A pulse on the base or grid of the first device turns it off and causes the second one to conduct until it receives a pulse on its base or grid. It then turns off, and conduction reverts back to the first. mumetal. An alloy having a high magnetic permeability used to make magnetic shields. Mumetal is an alloy of 14% iron, 5% copper, 1.5% chromium, and 79.5% nickel. muriatic acid. A form of commercial hydrochloric acid (HCl). One of the popular uses for muriatic acid is as a flux for cleaning metal in preparation for soldering. mushroomed head (damaged tool head). A damaged head on a chisel or punch caused by hammering on the tool. Mushroomed heads are dangerous, because a piece of the metal can be easily broken off and cause injury. A mushroomed head must be ground off of a tool as soon as it forms. mutual induction. The cause of a voltage being induced in one circuit by a changing current in another circuit when there are no electrical connections between the two. Changing current causes lines of magnetic flux to expand and contract. When this changing flux cuts across the conductors in another circuit, mutual induction causes a voltage to be induced in it. MVA (minimum vectoring altitude) (air traffic control). The lowest MSL altitude at which an IFR aircraft will be vectored by a radar controller, except as otherwise authorized for radar approaches, departures, and missed approaches. |
