《机电技术专业英语 教学课件 ppt 作者 徐起贺 张庆良pata a lesson Twenty-three》由会员分享，可在线阅读，更多相关《机电技术专业英语 教学课件 ppt 作者 徐起贺 张庆良pata a lesson Twenty-three（13页珍藏版）》请在金锄头文库上搜索。
1、,机电技术专业英语,2,Lesson Twenty-three,Text,Processes of mechanization have been developing and becoming more complex ever since the beginning of the Industrial Revolution at the end of the 18th century. The current developments of automatic processes are, however, different from the old ones. The “automat
2、ion” of the 20th century is distinct from the mechanization of the 18th and 19th centuries in as much as mechanization was applied to individual operations, whereas “automation” is concerned with the operation and control of a complete producing unit1. And in many, though not all, instances the elem
3、ent of control is so great that whereas mechanization displaces muscle, “automation” displaces brain as well2.,Mechanization and Automation,Lesson Twenty-three,The distinction between the mechanization of the past and what is happening now is, however, not a sharp one. At one extreme we have the ele
4、ctronic computer with its quite remarkable capacity for discrimination and control, while at the other end of the scale are “transfer machines”, as they are now called, which may be as simple as a convey or belt to another. An automatic mechanism is one which has a capacity for selfregulate; that is
5、, it can regulate or control the system or process without the need for constant human attention or adjustment3. Now people often talk about “feedback” as being an essential factor of the new industrial techniques, upon which is based an automatic selfregulating system and by virtue of which any dev
6、iation in the system from desired conditions can be detected, measured, reported and corrected. When “feedback” is applied to the process by which a large digital computer runs at the immense speed through a long series of sums, constantly rejecting the answers until it finds one to fit a complex se
7、t of facts that,Lesson Twenty-three,have been put to it, it is perhaps different in degree from what we have previously been accustomed to machines. But “feedback”, as such, is a familiar mechanical conception. The oldfashioned steam engine was fitted with a centrifugal governor, two balls on levers
8、 spinning round and round an upright shaft. If the steam pressure rose and the engine started to go too fast, the increased speed of the spinning governor caused it to rise up the vertical rod and shut down a valve. This cut off some of the steam and thus the engine brought itself back to its proper
9、 speed. The mechanization, which was introduced with the Industrial Revolution, because it was limited to individual processes, required the employment of human labor to control each machine as well as to load and unload materials and transfer them from one place to another. Only in a few instances
10、were processes automatically linked together and was production organized as a continuous flow.,Lesson Twenty-three,In general, however, although modern industry has been highly mechanized ever since the 1920s, the mechanized parts have not as a rule been linked together4. Electriclight bulbs, bottl
11、es and the components of innumerable massproduced articles are made in mechanized factories in which a degree of automatic control has gradually been building up5. The development of the electronic computer in the 1940s suggested that there were a number of other devices less complicated and expensi
12、ve than the computer which could share the field of mechanical control6. These devices mechanical, pneumatic and hydraulic have been considerably developed in recent years and will continue to advance now that the common opinion is favoring the extension of “automation”. Electronic devices, of cours
13、e, although not the sole cause of what is happening, are nevertheless in a key position. They are gaining in importance and unquestionably hold out exceptional promise for development in the future.,Lesson Twenty-three,New Words and Expressions,Lesson Twenty-three,Notes,1. The “automation” of the 20
14、th century is distinct from the mechanization of the 18th and 19th centuries in as much as mechanization was applied to individual operations, whereas “automation” is concerned with the operation and control of a complete producing unit. 20世纪的工业自动化之所以有别于18、19世纪的机械化，是因为机械化仅应用于操纵（执行）机构，而自动化则涉及整个生产单元中的
15、执行和控制两个（核心）部分。 be distinct from意为与有显著的区别；in as much as意为因为，引导一个原因状语从句，相当于because；whereas表示转折关系，相当于while，含义为相反的，但是，反之；be concerned with意为与有关。 2. And in many, though not all, instances the element of control is so great that whereas mechanization displaces muscle，“automation” displace brain as well.,L
16、esson Twenty-three,尽管不是所有的情况，但在大多数情况下，控制元件依然发挥着强大的力量，机械化已经代替了手工劳动，自动化代替了脑力劳动。 muscles意为肌肉，在这里是暗喻，表示体力劳动；brain意为脑，同样也是暗喻，表示脑力劳动；as well (as) 相当于and。 3. An automatic mechanism is one which has a capacity for selfregulate; that is, it can regulate or control the system or process without the need for constant human attention or adjustment. 自动调整机构能够自动调节系统，也就是说，它能在没有人干预和调整的情况下，自动对系统或生产过程进行控制和调节。 which 引导后面的定语从句，修饰one；selfregulate意为自我调节控制；without the need意为在不需要的情况下。 4. In general,
