测控技术与仪器专业英语 张凤登UNIT-7.Electronic Transducers

UNIT 7 Electronic Transducers,7.1 Text Transducer Types 传感器类型,New Words implement v. n. 执行，实现，完成；工具 sensor n. 传感器 measurand n. 被测量 vat n. 大桶 quantitative a. (数)量的，定量的 representative a. n. (有)代表性的，典型的；代表，典型 condition v. n. 调整节；条件 categorize v. 分类 transformation n. 转换 photovoltaic a. 光伏的。 cell光生伏打电池，太阳电池 piezoelectric a. 压电的 thermoelectric a. 热电的 thermistor n. 热敏电阻 RTD abbr. resistance temperature detector, 电阻式温度检测器 LVDT abbr. linear variable differential transformer, 线性差动变压器,Notes be not representative of 不能代表,Exercises 1. Answer the following questions. A transducer is a device that converts one form of energy or physical quantity into something new or more useful. Active transducers are those devices that generate voltage due to some form of physical change. Passive transducers respond to a measurand by altering some physical property. A passive transducer must be energized by an external source in order for it to function. Active transducers are usually used as the energy source of an electrical signal. These methods are electrostatic, electrochemical, electromechanical, photovoltaic, piezoelectric, and thermoelectric. Passive transducers are often described by the electrical property being controlled. In passive transducer operational theory, the electrical property being altered and the method of changing this property are important concepts.,Exercises (continue) 2. Replace the underlined parts in the following sentences with words or phrases from the text that best keep the original meanings. Bar coding (条形码) is mainly used for automatic identification today. (primarily) The Hall-effect (霍尔效应) principle is the operational basis of an active transducer that implements the detection of changes in magnetic field strength. (achieves) Thermistors act as an RTD, except they have a negative temperature coefficient and a nonlinear resistance-temperature relationship. (respond) Voltage is induced in a conductor placed in a magnetic field owing to relative motion between the conductor and the field. (due to) A photovoltaic sensor changes light energy directly into electrical energy. (converts) Thermocouples are thermoelectric transducers related to Seeback-effect (塞贝克效应). (involved in) The inductance of coil or inductor may be modified by the number of coil turns and the core material. (altered or changed) Level control by nuclear radiation has numerous applications in process tanks, reactors, bins (仓), pipes, silos (地下室), hoppers (料箱，料斗), and vessels. (a rather large number of ),7.2 Reading and Translation Transducer Characteristics 传感器特性,New Words and Phrases transfer træns'f v. 传递，转换 quantity 'kwntti n. 量 ascertain ,æs'tein v. 确定 stress stres v. n. 受压力；应力 illumination i,lju:mi'nein n. 光照，发光；照明度 incident 'insidnt a. 入射的 shutter 't n. 快门，光闸 bellows 'beluz n. 波纹管 seismic 'saizmik a. 震动的， mass 震动质量块 diaphragm 'daifræm n. 膜片 thermocouple ':mu,kpl n. 热电偶,斜体部分参考译文: Generally, the purpose served by the transducer is to ascertain the magnitude of some particular phenomenon under investigation, and the value determined by the transducer is generally, but not always, quantitative. 通常，采用传感器的目的，是通过测量确定某特定被研究现象（量）的大小，传感器测得的值不一定总是定量的。 In a piezoelectric transducer, energy is converted into a change in electrostatic charge or voltage generated by certain crystals when mechanically stressed. 在压电传感器中，当某些晶体受机械应力，能量转换为生成静电荷或电压的变化。 Since a capacitor consists essentially of two conductors or plates separated by an insulator, the dielectric, a change of capacitance can occur when a displacement of the sensing element causes one conductive surface to move toward or away from the other conductive surface . 由于电容器基本上由用绝缘体、电介质隔开的二个导体或极板组成，当敏感元件的位移使一个导电表面向另一个导电表面靠近或偏离时，会产生电容的变化。,7.3 Further Reading Photovoltaic Cells and Photoresistors 光生伏打电池和光敏电阻,New Words photoresistor ,futuri'zist n. 光敏电阻 calibrate 'kælibreit v. 校准,Notes in the range of about half a volt 约在0.5V量程范围内 nickel-cadmium battery 镍镉电池组 cadmium-sulfide 硫化镉 cadmium-selenide 硒化镉,7.4 General Knowledge 如何写好英文句子 1. 写句子时应注意的事项 避免使用多余或累赘的字。文章中尽量使用直接（direct）、简洁（concise）的句子，不要出现意思重叠的字。 【例7-1】It is frequently her custom to come and see us on Sunday. （她经常习惯于在星期日来看我们。） （误） custom已有经常的意思，与frequently造成重叠。为避免这个问题，可以换成下列句子： She frequently comes to see us on Sunday. （它经常在星期日来看我们。） 上述句子用frequently表示经常的习惯。 避免过度使用代名词。通常情况下，文章中不能过多地使用it，that，he，they等代名词，尤其是数个人物或事物同时出现在一篇文章中时。 多用主动语态，少用被动语态 。 避免使用俚语（slang word）。书写句子时，尽量利用英文句型（sentence pattern）和成语（idiom），也可适当地引用格言（maxim）或名人所说的话，一般不采用俚语。 避免使用缩写。缩写虽然可使句子更简洁，但不属于正式写法。 例如，I dont know. （不正式） I do not know. （较佳）,如何写好英文句子(续) 2. 好句子需要满足的条件 合乎文法的句子并不一定就是好句子，一个好句子需要满足下列条件： 统一性（unity）。一个句子无论长短，只容许有一个重心，否则会造成句意不清。 强调性（emphasis）。以加下划线（underline）、用不同字体、重复该字、或改变句法顺序，来达到强调的效果。 。 和谐性（coherence）。句意清晰，并合乎逻辑。 【例7-4】We saw many dead soldiers riding across the battlefield. （我们看到许多死去的士兵骑马越过战场。） 句意不清，不合逻辑。若写成 Riding across the battlefield, we saw many dead so