专业英语作业
通信与信息工程学院
专业英语结课作业
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作业时间：2017年12月23日成绩：
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通信与信息工程学院
二〇一七年
Passage B Liquid Lasers,the Free-electron
Laser and the X-ray Laser
Liquid lasers
Liquid Lasers If gases and solids can sustain laser action, why not liquids? Indeed liquids can be the active media in lasers, and there’s a large and important family of liquid lasers based on organic dyes. The dyes, which are actually solids at room temperature, are dissolved in a liquid (generally an organic compound, such as alcohol) to form a solution.液体激光器如果气体和固体能维持激光作用，为什么液体不能呢？的确，液体可以在激光工作介质，并有一个大的和重要的家庭基于有机液体激光器C染料。这些染料在室温下实际上是固体，它们被溶解在液体中（通常是有机化合物，如酒精）形成溶液。
What makes the dye laser special is the nature of its transitions. In almost all other lasers, the laser transition is between two states at fixed energy levels, which means that the laser emission is in a fixed, very narrow, well-defined band of wavelengths. Even in carbon dioxide lasers and other types with a family of closely spaced energy levels, there are discrete transitions at distinct wavelengths. Organic dyes, in contrast, have energy levels so closely spaced that to all intents and purposes they form a continuum. This large number of levels exists because of the complexity of the dye molecules, and as a result, electronic transitions in the dye can produce a broad range of wavelengths, most of them visible.
染料激光器之所以特别，是因为它的过渡性质。在几乎所有其他激光器中，激光在固定能级的两种状态之间发生跃迁，这意味着激光发射在一个固定的、非常窄的、定义良好的波段中。即使在二氧化碳激光器和其他具有紧密间隔能级的类型中，在不同的波中也存在着离散的跃迁。长度。相比之下，有机染料的能级如此密集，以致于它们都形成了连续统。由于染料的复杂性，这一数量级存在。分子，因此，染料中的电子跃迁能产生宽范围的波长，大部分波长可见。
It’s possible to devise an optical system that will select a single wavelength in the
laser’s range. Moreover, these optics can be adjusted to tune t he output wavelength continuously across the range of wavelengths possible for that particular dye. Most dyes are tunable across at best 10 percent of the visible region, but it’s possible to arrange several dyes in sequence so as to be able to tune the output wavelength across the entire visible spectrum.
有可能设计出一种能在激光范围内选择单个波长的光学系统。此外，这些光学元件可以被调整以连续调整输出波长。可能的波长为特定的染料。大多数染料在可见光区域的10%处是可调谐的，但也可以按顺序排列几种染料以便调谐T。他在整个可见光谱上输出波长。
What makes a commercial dye laser worth its price tag of $5,000 to $50,000 is the fact that it can be tuned precisely—often with just a twist of a dial—to emit a smaller range of wavelengths than any other source, and that within this range, the light is much more intense. This can make a dye laser invaluable for experiments in such areas as chemistry and atomic physics.
是什么使一个商业染料激光价值5000美元至50000美元的事实是，它可以精确地调整-往往只是一个扭曲的拨号发出更小的波长范围比任何。在这个范围内，光线要强烈得多。这可以使染料激光器在化学和原子物理等领域的实验中发挥重要作用。
Incidentally, one of the strangest lasers ever built was a dye laser. It doesn’t even emit a beam, but rather a halo. Z. G . Horvath, of the Central Research Institute for Physics in Budapest, Hungary, and two colleagues at the Lebedev Physics Institute in Moscow built a disk-shaped laser that emits light along all 360 degrees of its circumference. In this device, the circumference is coated with a partially reflecting film, producing a disk-shaped laser cavity. At the heart of this weird laser is a dye that’s pumped by another laser. Horvath believes it should be possible to extend his technique to make a spherical laser—one that will emit laser light from the entire surface of a ball-shaped device. But it’s unclear if either a disk or a spherical laser will ever find applications outside the laboratory.
顺便说一句，有史以来最奇怪的激光器之一是染料激光器。它甚至不发出光
束，而是一束光环。G Z.。Horvath，中央研究院物理在布达佩斯，匈牙利，和莫斯科的列别捷夫物理研究所的两个同事建立了一个圆盘状的激光发射在360
度的圆周光。在该装置中，四周涂上一部分反射膜，生产的盘形激光器谐振腔。这种奇怪激光的核心是由另一个激光器泵浦的染料。Horvath认为，应该尽可能延长自己的技术做一个球形激光能发射激光从一个球形装置的整个表面。但目前还不清楚，无论是磁盘或球形激光将在实验室以外找到应用程序。
The Free-Electron Laser
A recent addition to the laser bestiary is a strange creature known as the free-electron laser. The term free electroncomes from the fact that the active medium emitting the light is a beam of electrons, free from atoms, which is passing through a magnetic field.
最近除了激光集是一个奇怪的生物被称为自由电子激光器。从事实的活性介质发光是一束电长期免费无原子的，穿过磁场的。
This laser requires a large electron accelerator or storage ring to provide the electron beam. Then it needs a set of large, powerful magnets to keep changing the direction of the beam. The first such laser was operated at the Stanford Linear Accelerator Center in a 1977 experiment by John M. J. Madey, a Stanford University physicist. To give you an idea of what league we’re in here, the Stanford accelerator cost hundreds of millions of dollars to build, and that’s just one part of t he laser. You can get by with a small accelerator, however, although it’s not yet clear how small.
这种激光器需要一个大型的电子加速器或储存环来提供电子束。然后，它需要一组巨大的，强大的磁铁来不断改变光束的方向。第一种激光是在斯坦福线性加速器中心，1977个实验由John M. J. Madey操作，斯坦福大学的物理学家。为了让你知道我们在这里是什么联盟，斯坦福大学。加速器耗资数亿美元建造，这只是激光的一部分。不过，你可以用一个小加速器，虽然还不清楚它有多小。
What has aroused interest is the prediction that the output of free electron lasers should be tunable across a wide range of wavelengths: perhaps from the microwave region all the way to X-rays, although no single device would operate across that
entire range.
是什么引起了人们的兴趣是预测，自由电子激光器的输出应该在宽范围的波长可调谐的：也许从微波波段的X射线，虽然没有单一的设备将在整个范围内操作。
The military is interested in this laser for an obvious reason—its high power. Originally, it was thought that a beam of electrons would itself make a good weapon. But it would be difficult to focus a beam of negatively charged electrons, which would mutually repel one another, over long distances. Transforming this high-energy, but cumbersome; beam into a laser beam would solve a lot of problems. A laser beam is easier to focus on a distant target. A series of experiments to test freeelectron lasers, sponsored by the Defense Advanced Research Projects Agency, was getting underway as this book was being written.
军方对这种激光器很感兴趣，原因很明显是它的高功率。最初人们认为电子束本身就是一种好武器。但是很难把重点放在A上。带负电荷的电子束，它们相互远距离地互相排斥。把这种高能但笨重的光束转换成激光束可以解决很多问题。激光束更容易聚焦在远处的目标上。一系列的实验来测试自由电子激光器，由美国国防高级研究计划局主办，正在为这本书什么是书面的。
Enter The X-ray Laser (Maybe)
There’s no better way to learn how fast-moving a field is than to write a book about it. We were in the final stages of finishing this chapter when a new type of laser apparently emerged on the scene: the X-ray laser.
没有比学习写一本书更好的方法了。我们正处于完成这一章的最后阶段时，一种新型激光显然出现在了现场：X射线激光。
We use the word apparently, because it isn’t yet clear exactly what happened. Operation of an X-ray laser at 1.4 nanometers (1.4×10-6mm) was reported in Aviation Weekand Space Technology, and it’s clear that an experiment was performed by a group at the Lawrence Livermore National Laboratory in California. However, what happened is not yet certain. Livermore’s official reaction is “no comment,” and there’s much skepticism among other researchers about some of the details in “Aviation
Leak,” as the magazine is called in the aerospace community.
我们使用这个词显然是因为目前还不清楚究竟发生了什么。在1.4纳米的X 射线激光手术（1.4×10 - 6mm）在和<
Laser researchers lend to be very cautious about reports of X-ray lasers, because this isn’t the first such report.Back in 1972, a physicist at the University of Utah made a big splash by announcing that he had built an X-ray laser. He hadn’t, however. The effects he thought were caused by X-rays were really caused by something else. His efforts to publicize the “discovery” (which was reported in Newsweekand elsewhere) before thoroughly checking it out left him disgraced in the physics community.
激光研究人员对X光激光器的报道非常谨慎，因为这不是第一次这样的报道。早在1972，犹他大学的一位物理学家就发表了一篇大文章。他建造了一个X光激光。然而，他没有。他认为由X射线引起的效应真的是由别的东西引起的。他宣传“发现”的努力（据报道）newsweekand别处）前彻底检查出来让他丢脸了物理学界。
There’s another reason for skepticism too. Even in theory, an X-ray laser is very hard to build. For example, just to produce a population inversion on a 0.1-nanometer transition takes two watts per atom. Atoms excited on such a transition drop down to the ground state in about 10-15sec. The very process of pumping an X-ray laser would vaporize it. And it wouldn’t even be a laser oscillator, because no mirrors exist for X-rays, making it impossible to build a resonator.
还有另一个理由让人怀疑。即使在理论上，X光激光器也很难制造.。例如，仅仅为了在0.1纳米跃迁上产生一个粒子数反转，每a需要2瓦特。汤姆.原子激发这种过渡下降到地面状态约10 - 15秒。抽X光激光的过程会使它汽化。它甚至不会被激光振荡器，因为因为没有X射线的镜子，所以不可能制造出一个谐振腔
Why bother trying? Because it’s a challenge to physicists. Of course, there are
some potential applications for X-ray lasers, some of them military, a fact that physicists regularly point out to the people who fund their research. Yet the people working on the problem generally seem more interested in the intellectual challenge of finding a way of doing this very difficult task.
为什么要费心尝试？因为这是对物理学家的挑战。当然，X射线激光器有一些潜在的应用，其中一些是军用的，这是物理学家经常指出的事实。人们谁资助他们的研究。然而，研究这个问题的人似乎更感兴趣的是如何找到一种方法来完成这项艰巨的任务。
“Difficult” may be too mild a word. It reportedly took a small nuclear explosion to pump Livermore’s X-ray laser. Much of the energy from such an explosion is in the form of X-rays, and these X-rays excited atoms to produce an X-ray population inversion. The whole process happened very fast, probably in about one picasecond (10-12sec, or one trillionth of a second) or possibly even less, according to X-ray laser researchers outside Livermore. Aviation weeksaid that during that ultra-short pulse, the laser produced a very high level of energy—hundreds of trillions of watts. Yet because the pulse was so short, the total energy in the pulse was probably only a few hundred joules (a joule is the amount of energy provided by a power of one watt delivered for one second)— enough to keep an ordinary light bulb burning for only few seconds.
“难”字可能太温和了。据报道，它进行了一次小型核爆炸来发射摩尔的X 光激光。这种爆炸的大部分能量是以X射线的形式，这些X射线引用原子产生X射线粒子数反转。整个过程发生得非常快，可能在一皮秒(10-12秒，或trillionth 秒)，甚至更少，根据报告。利弗莫尔以外的X光激光研究人员。航空weeksaid，超短脉冲激光产生的过程中，一个非常高的水平，数百万亿瓦的能量。然而，由于脉冲E是如此的短暂，在脉冲的总能量大概只有几百焦耳（Joule是由1瓦特交付一第二电源提供的能量的量足以保持一般）只需几秒钟就可以燃烧的灯泡。
英语作业及答案
下面的范文中有很多错误，请找出形容词与副词的混淆、冠词的遗漏和误用、介词和代词的误用等错误，并检查句子的完整性、单词拼写、主谓的一致性、动词和现在分词是否混淆、复数形式、动词的时态、词汇选择、词性、单词的顺序等问题。 (几乎每个句子都有错误) An university education is a goal of many high school students. Some students want to go into a profession that requires an university degree. But there are other professions that do not require a degree, but require certification from a technological college. The reasons why students make decisions to go to technical college instead of university probably have a lot to do with their choice of career, their own academic abilities and their financial situation. First of all, students make their choices for post-secondary education based on the fields that interest them. A student who is interested in medicine might decide to university, into a pre-med program to prepare to become a doctor, or they might go to nursing school or a nursing program in a technical college. Some career choices offer a choice of educational route. The university route is usually more intense and takes longer. For example, an interior designer might take a one or two year program at a college, or choose to do the degree program as a part of the architectural department at a university. Other career choices involve certification that is available at a college, like broadcast journal or
数学专业英语课后答案
2.1 数学、方程与比例 （1）数学来源于人类的社会实践，包括工农业的劳动，商业、军事和科学技术研究等活动。 Mathematics comes from man’s social practice, for example, industrial and agricultural production, commercial activities, military operations and scientific and technological researches. （2）如果没有运用数学，任何一个科学技术分支都不可能正常地发展。 No modern scientific and technological branches could be regularly developed without the application of mathematics. （3）符号在数学中起着非常重要的作用，它常用于表示概念和命题。Notations are a special and powerful tool of mathematics and are used to express conceptions and propositions very often. （4）17 世纪之前，人们局限于初等数学，即几何、三角和代数，那时只考虑常数。 Before 17th century, man confined himself to the elementary mathematics, i. e. , geometry, trigonometry and algebra, in which only the constants were considered. （5）方程与算数的等式不同在于它含有可以参加运算的未知量。 Equation is different from arithmetic identity in that it contains unknown quantity which can join operations. （6）方程又称为条件等式，因为其中的未知量通常只允许取某些特定的值。Equipment is called an equation of condition in that it is true only for certain values of unknown quantities in it. （7）方程很有用，可以用它来解决许多实际应用问题。 Equations are of very great use. We can use equations in many mathematical problems. （8）解方程时要进行一系列移项和同解变形，最后求出它的根，即未知量的值。To solve the equation means to move and change the terms about without making the equation untrue, until the root of the equation is obtained, which is the value of unknown term. 2.2 几何与三角 （1）许多专家都认为数学是学习其他科学技术的必备基础和先决条件。 Many experts recognize that mathematics is the necessary foundation and prerequisite of studying other science technology. （2）西方国家的专家认为几何起源于巴比伦和埃及人的土地测量技术，其实中国古代的数学家对几何做了许多出色的研究。 The western experts think that geometry had its origin in the measurements by the Babylonians and Egyptians of their lands. Infect, the ancient Chinese mathematicians made much remarkable study for geometry. （3）几何的学习使学生在思考问题时更周密和审慎，他们将不会盲目接受任何结论。 In studying geometry, the student is taught to think clearly and critically and he is led away from the practice of blind acceptance of any conclusions. （4）数学培养学生的分析问题的能力，使他们能应用毅力、创造性和逻辑推理来解决问题。
专业英语大作业
专业英语大作业 一：英译汉 翻译范围TCP/IP Illustrated, V olume 1: The Protocols 5.1~5.5 15.1~15.2 第5章RARP：逆地址解析协议 5.1简介 5.2 RARP报文格式 5.3 RARP示例 5.4 RARP服务的设计 5.5小结 练习 5.1简介 一个拥有本地磁盘的系统通常是从磁盘文件读取配置文件中获取其IP地址。但一个没有磁盘的系统，如X终端或无盘工作站，需要一些其它方式去获得其IP地址。 每个系统在网络上都有一个唯一的硬件地址，由网络接口的制造商分配。 RARP的原则是无盘系统从接口卡上读取其独特的硬件地址，并发送RARP请求（网络上的广播帧）要求别人对无盘系统的IP地址（使用RARP回应）进行应答。 虽然这个概念很简单，执行往往比ARP更难，在本章后面会描述其原因。 RARP的正式规范是RFC 903。 5.2 RARP报文格式 RARP报文的格式几乎与ARP报文是相同的（图4.3）。唯一的区别是，RARP 的请求或应答帧类型为0×8035，并且在操作层RARP请求值为3、RARP应答值为4。 图4-3 ARP在网络上请求与应答报文的格式 与ARP一样，RARP服务器请求是广播和RARP应答通常是单播。 5.3 RARP示例 在我们的网络，我们可以强制sun主机从网络引导，而不是它的本地磁盘。 如果我们在主机bsdi上运行RARP服务器和tcpdump，我们得到如图5.1所示的输出。我们使用-e参数去标记tcpdump的打印硬件地址：
图5.1 RARP请求和应答。 该RARP请求是广播（1号线）的，第2行的RARP应答是单播的。第2行的输出，“at sun”,意味着RARP应答包含了主机sun（140.252.13.33）的IP地址。 在第3行，我们看到，一旦sun接收其IP地址，它会发出一个TFTP读请求（RRQ）的文件8CFCOD21.SUN4C。（TFTP是简单文件传输协议，我们在第15章进行详细描述）。在文件名中的8个十六进制数字是sun主机的IP地址140.252.13.33的十六进制表示形式。这是在RARP应答中返回的IP地址。该文件名的其余部分，后缀SUN4C表示系统正在引导的类型。 Tcpdump表示第3行是一个长度为65的IP数据报，而不是一个UDP数据报（实际上它确实是），因为我们运行tcpdump命令使用-e参数，看硬件级别的地址。另一点，在图5.1要注意的是在第2行的以太网帧的长度似乎比最小较短（我们所说的是在4.5节60字节）。原因是我们的系统，该系统上运行的tcpdump 发送该以太网帧（BSDI）。该应用程序rarpd，写42字节到BSD分组过滤器装置（14字节的以太网报头和28字节的RARP应答），这是什么的tcpdump收到的副本。但以太网设备驱动程序垫这个短帧的最小尺寸为传输（60 ）。如果我们在另一个系统上已经运行的tcpdump ，长度会是60。 我们可以看到在这个例子，当这种无盘系统接收在RARP应答它的IP地址，它会发出一个TFTP请求来读取一个引导映像。在这一点上，我们不会进入其他详细介绍无盘系统是如何引导自己。（第16章介绍了使用RARP ，BOOTP和TFTP无盘X终端的引导顺序。） 图5.2表示出了如果有在网络上没有RARP服务器所得到的数据包。每个数据包的目的地址为以太网的广播地址。以太网地址跟随的是目标硬件地址，并按照发送端的硬件地址发送。
全国农业推广硕士专业英语作业题
全国农业推广硕士专业英语作业题 Part One Vocabulary and Structure Fill in the balnks with words or expressions chosen from the following list. Change the form where necessary. speculate specify commitment despite desirable access contribution adolescent banish inhabitant identify frustration impact sanction impressive hit upon switch correspond to obligation various 1、The U.N would impose economic against the offending nations or government. 2、The boys and girls are fond of behaving differently from seniors. 3、I a satisfactory explanation. 4、Man on the origin of the universe since the beginning og the human history. 5、You can from your mind the idea of holding a party during
the examination week. 6、The company that we would have one subject to another. 7、The American Congree the British Parliament. 8、We are trying to find some people who have a real sense of to the job. 9、the sandstorm, the Johnsons drove to the xilla to celebrate their 25th anniversary of marriage. 10、You are under no to pay for goods which you did not order. 11、Men still hold the vast majority of the least- or modt-dangerous jobs, such as loggers and miners. 12、He doesn’t expect to see changes overnight. 13、Students must have to good books.
《人文英语2》形成性考核册作业题目和答案更正版
电大资源网《人文英语（2）》形成性考核册参考资料 《人文英语（2）》是国家开放大学 2017 年春季新开的课程之一，对国家开放大学的文科专业学生进行统一考试。该资料对学生完成学习任务起着一定的辅助作用。电大资源网还有国家开放大学其他课程的参考资料，可以参考。 注：本科目已按字母排版整理成期末考试小抄 作业 1 一、交际用语（每小题 2 分，共 10 分） 1-5 题：选择正确的语句完成下列对话，并将答案序号写在题前括号内。 1.-Would you like me to help you make a plan for the summer vacation? B - . A.No, I already have my plans. B.I’d love to, but I’m busy today. C.I’m ill, so I shouldn’t go out. 2.-Can I take your order, madam? A - . A.Yes. I’d like an Italian soup to start with. B.Yes, it’s as quiet as we expected. C.No, the price’s reasonable. 3.-What are you going to do in the 2022 Winter Olympics? B - . A.Yes, I have been there. B.I’m going to be a volunteer. C.I am traveling abroad. 4.-I’d like to invite you to my birthday party on Saturday evening. A - . A.Thank you for your invitation. B.I don’t want to join your party. C.I did not go to the party that night. 5.-Do you think you are the suitable person for this position? C - . A.I’m not sure if I will be here for the task. B.I don’t think Xiao Ming is the right person to count on. C.Yes. I’m hard working and I think I am suitable for this position. 二、选择填空（每小题 2 分，共 30 分） 6-20 题：阅读下面的句子，从 A、B、C 三个选项中选出一个能填入空白处的最佳选项，并将答案序号写在题前括号内。 6.I think I am C for this position. https://www.sodocs.net/doc/d89186059.html,plete B. confident C. competent 7. A successful cover letter will make a great B. A.progress B. impression C. contribution 8.Will the AIDS patients benefit A the new drug? A.from B. by C. of 9.You can B some bottles of wine, or some chocolates, or a bunch of flowers. A. bring up B. bring along C. bring down 10.I’m A because there are so many options. I can’t make a decision. A.puzzled B. excited C. depressed 11.If there is any change about the time of the meeting, please notify us C. A.in time B. on time C. in advance 12.There must be something wrong with my computer，C there? A.mustn’t B. needn’t C. isn’t
专业英语部分习题答案参考.doc
b-毗喘pyridine 巴比妥酸:barbituric acid 比电导conductance 不规则的:irregular 崩解剂disintegrant C--萃取extraction 成团:ogglomerotion 测量仪measurement 肠液:intestinol fluid d-胆固醇cholestero 对映体:enontiomer 电极electrode 代谢:metobolism f-反相渗透reverse osmosis 分布:disposition g-构象：conformotion 固化:solidize 卜-甲苯toluene 静脉注:introvenous injection 挤压:compress 聚集:aggregate 胶囊capsule I一粒子:particle 立体选择性:stereoselectivity 利用率:availability 灭菌产品sterile products n—粘合剂odhesive P—偏振光:polarized light 片剂tablet 酉己剂elixir 排泄:excretion q一起女台原料starting materials(raw materials) q 醛aldehyde 「一溶解度:solubility 乳剂emulsion 润滑剂lubricant s-释放:release 渗液solution 生物膜:biologic membrane 生物碱okoloid, t…糖浆syrup 甜味剂sweetener w-丸剂pill 微生物microorganism 胃液:gastric fluid 稳定态:steady-state x-?旋光异构现象:optical isomerism 悬浮液suspension 香味剂flavor 稀释剂diluent 形状:shape 吸收absorption 消除:elimination y-胰岛素insulin 压片:tablet compression z-中间体intermediote 重结晶recrystallization 左旋:levorotation 蒸徭distillation 组织tissue a-asymmetric carb on 不对称碳absorption 吸收action 动作odhesive 粘合剂c-contamination 污染chirality:手性compress 压缩composite 合成的compressibility:可压缩性compaction:压紧contaminotion specialize 特殊污染conductivity 电导率control控制clinical:临床的 d- design:设计dry:干燥delivery:传送 e-巳xtgnd:延长epoxide:环氧化物 f- formulation:$ij 剂fluidity:流动性function:功能 g- geometric isomerism:几何异构 h- hormone 激素hydrolysis diastereoisomer:水解非对映异构体 heterogeneous catalyst 多相催化剂， i- irrigating 冲洗 m- metabolite代谢物medication药物治疗medicine内服药mill:研磨measure 尺寸mix:混合microorganisms 微生物 o- ophthalmic 眼药 p- polysaccharide 多糖peptide 肽plosmo 血浆penicillin 青霉素， precursor:前体partition coefficient:狭义分配系数pharmaceutical 制药的 parenteral 注射药物pycogens 热源procedure:程序 q- quality 性质quantity 数量 s- steroid 笛类steric effect:空间效应stereoselectivity:^体选择性 screening:过筛sustain :维持
英语大作业
《自动化专业英语》翻译大作业 所选文字出处：选自论文《PLC的发展和应用》 班级：学号：姓名：成绩： PLC全名为可编程控制器，定义是种数字运算操作的电子系统，专为在工业环境应用而设计的，主要结构由电源，中央处理单元，存储器，输入输出接口电路，功能模块，通信模块组成。PLC具有通用性强、使用方便、适应面广、抗干扰性强、编程简单等特点，在军事、国防、航空航天、交通、工业生产中的地位，在可预见的将来中是无法取代的。PLC有很多流派，我国的PLC研发、生产和应用发展很快，尤其在应用方面更为突出。 PLC的发展历程和主要流派 在工业生产过程中，大量的开关量顺序控制，它按照逻辑条件进行顺序动作，并按照逻辑关系进行连锁保护动作的控制，及大量离散量的数据采集。传统上，这些功能是通过气动或电气控制系统来实现的。1968年美国GM（通用汽车）公司提出取代继电气控制装置的要求，第二年，美国数字公司研制出了基于集成电路和电子技术的控制装置，首次采用程序化的手段应用于电气控制，这就是第一代可编程序控制器，称Programmable Controller（PC）。个人计算机（简称PC）发展起来后，为了方便，也为了反映可编程控制器的功能特点，可编程序控制器定名为Programmable Logic Controller（PLC），现在，仍常常将PLC简称PC。PLC的定义有许多种。国际电工委员会（IEC）对PLC的定义是：可编程控制器是一种数字运算操作的电子系统，专为在工业环境下应用而设计。它采用可编程序的存贮器，用来在其内部存贮执行逻辑运算、顺序控制、定时、计数和算术运算等操作的指令，并通过数字的、模拟的输入和输出，控制各种类型的机械或生产过程。可编程序控制器及其有关设备，都应按易于与工业控制系统形成一个整体，易于扩充其功能的原则设计。上世纪80年代至90年代中期，是PLC发展最快的时期，年增长率一直保持为30~40%。在这时期，PLC在处理模拟量能力、数字运算能力、人机接口能力和网络能力得到大幅度提高，PLC逐渐进入过程控制领域，在某些应用上取代了在过程控制领域处于统治地位的DCS系统。在世界上200多家PLC厂商，400多品种的PLC产品大体可以按地域分成三个流派：一个流派是美国产品，一个流派是欧洲产品，还有一个流派是日本产品。同一地区的产品相互借鉴的比较多，相互影响比较大，技术参透比较深，面临的主要市场相同，拥护要求接近，这一切就使得同一地域的PLC产品表现出比较多的相似性。美国PLC技术的形成与欧洲PLC技术的形成是在相互隔离的情况下，独自研究开发获得的，因此美国的PLC产品与欧洲的PLC产品常表现出来明显的差异性。日本的PLC技术是由美国引进的，因此日本的产品对美国的产品有一定的继承性。世界上比较先进的PLC生产厂家有德国的的西门子、日本的三菱、美国的A-B公司等等。
专业英语作业
1、A VPN is physically public but virtually private 2、Set is a secure protocol jointly designed by Mastercard and Visa with the backing of Microsoft, Netscape, IBM, GTE, SAIC, and other companies. 3、 The physical components of a computer are collectively called hardware 4、The term payment card refers to Credit card 、Charge card 5、The fifth generation computers, with artificial intelligence,are being developed and perfected now. 6、In the future, we may eliminate the needs for physical money.Indeed ,we would exchange digital cash For goods and services. 7、The basic input device on a small computer is a keyboard 8、You must have seen her in her office last Friday; she's been out of town for two weeks. 9、The ability to store knowledge makes computers different from every other machine ever invented. 10、The fifth generation computers, with artificial intelligence,are being developed and perfected now. 11、DigiCash or E-cash is an electronic payment system developed by Dr.David Chaum, who is widely regarded as an inventor of digital cash. 12、Transaction changed to your telephone bill are called E-charge payments 13、Smart cards are cards that look like credit cards, but store information on a microprocessor chip instead of magnetic strips. 14、https://www.sodocs.net/doc/d89186059.html, is a free service that earns a profit on the transaction cost, which is money that is deposited in PayPal accounts 15、This ticket entitles you to a free meal in our new restaurant 16、Program that can destroy another computer’s programs are called viruses 17、Data and program instructions are stored in storage 18、Electronic wallets that store digital certificates are particularyly handy when you shop at a site that requests user authentication information. 19、The percentage of times an ad is clicked on based on the number of times it’s viewed is called CTR 20、The purpose of input device is to enter commands .、to input data
计算机专业英语作业及答案
计算机专业英语作业答案（供参考） 计算机专业英语作业1 第1－3章作业一．( 词汇) (一)．(写出下列词组的汉语。) 1．（）中央处理器 2 标题栏 3．操作系统4．个人计算机 5．菜单栏6．桌面排版 7．电子表格8．硬盘 9．数据库10．光标 (二)．.(根据汉语写出相应的英语缩写。) 1．随机存储器2．只读存储器 3．传输控制协议P 4．数字视频光盘5．通用串行总线6．计算机辅助设计7．计算机辅助制造8．中央处理器 (三)．.(根据汉语写出相应的英语。) 1．键盘2．鼠标3．扫描仪 4．打印机5．输入6．输出 7．显示器8．存储器9．数据库 10．操作系统11．应用软件 12．字处理器13．网络浏览器 二．(T) (F).(判断正误。) 1．, . (√)
2．'s . (√) 3．: . (√) 4． a 2000 . (×) 5．( ) a . (√) 6. , a . (√) 7. , ’s . (×) 8. ’t . (×) 9. . (×) 10. . (×). 三．.(将左列的词汇与右列相应的汉语匹配。) （一）． 1. （） a. 操作系统 2. b. 输入. 3. ( ) c. 只读存储器 4. ( ) d. 应用软件 5. e. 中央处理器 6. f. 系统软件 7. g. 硬件 8. h. 随机存储器 9. i. 内存 10. j. 输出 1．e 6. j 2．g 7．a 3．h 8. d 4．c 9. f 5．b 10. i (二) ． 1. a
2. b a 3. c 4 d a 0 1 5. e a 6. f 7. g 8. h a 9. i a 1．d 6. a 2．g 7．f 3．h 8. c 4．b 9. e 5．i 四．, . （从下面方框中选择合适的词或表达，以其适当的形式填空。） 1． () . , a . , . , , . , . 2. , , . , a a a , a , a , a . , , . a , , a . , 1-2-3 . a , a ( ) . 3.
网络教育英语专业 [西南大学网络教育《大学英语一》大作业答案]
1、(5) Which of the following is not true? ADick stayed at a nice hotel in the center of the city. BDick didn't work on the first night of his arrival. CDick forgot to send his wife a telegram. DDick wanted to go back to his hotel in a taxi. 正确答案C 2、题目Reading comprehension 1(4) Who would send him the name and address of his hotel? AThe manager of his hotel. BThe police office. CThe taxi driver. DHis wife.
正确答案D 3、题目Reading comprehension 1(3)Where did Dick stay in New York? A In the center of the city. BIn a hotel. CIn a restaurant. DAt his friend's house. 正确答案B 4、题目Reading comprehension 1(2) Why did his wife want a telegram from him? ABecause she didn’t know his address yet
BBecause she wanted to go to New York, too CBecause she might send him another telegram DBecause she couldn't leave her husband by himself in New York. 正确答案A 5、1) Dick flew to New York because _________. Ahe went there for a holiday Bhe had work there Che went there for sightseeing D his home was there 正确答案B
专业英语作业
1. 获取更多信息如摘要的格式和类别,请参考附上的“提交摘要说明”。 For more information such as the format and the categories of the abstract, please refer to the attached “Instructions for Submission of Abstracts”. 2. 随信寄上两份论文摘要和一份个人简历，请查收。请便中告知我是否有资格申请大会的资助。 We are enclosing two copies of paper and a resume, please check. Please inform me if there are eligible to apply for funding of the conference. 3.非常感谢你的信息和对GEC2004感兴趣。不幸的是我们对参与者不提供任何财务援助。对组织会议有很大帮助的人将会提供一些金融帮助,例如给主题演讲或教程,组织一个邀请会话等。 Thank you very much for your message and for your interest in GEC2004. Unfortunately we can’t offer any financial assistance for regular participants. There will be some financial help available only for people who give considerable help in organizing the conference, e.g. giving a keynote lecture or a tutorial, organizing an invited session, etc. 4. 感谢你的8月15日来信，邀请我去参加2003年1月25日至28日在密歇根州的Bellaire即将举行的“2003国际会议比较文学”。
数学专业英语课后答案
2.1数学、方程与比例 词组翻译 1.数学分支branches of mathematics，算数arithmetics，几何学geometry，代数学algebra，三角学trigonometry，高等数学higher mathematics，初等数学elementary mathematics，高等代数higher algebra，数学分析mathematical analysis，函数论function theory，微分方程differential equation 2.命题proposition，公理axiom，公设postulate，定义definition，定理theorem，引理lemma，推论deduction 3.形form，数number，数字numeral，数值numerical value，图形figure，公式formula，符号notation(symbol)，记法/记号sign，图表chart 4.概念conception，相等equality，成立/真true，不成立/不真untrue，等式equation，恒等式identity，条件等式equation of condition，项/术语term，集set，函数function，常数constant，方程equation，线性方程linear equation，二次方程quadratic equation 5.运算operation，加法addition，减法subtraction，乘法multiplication，除法division，证明proof，推理deduction，逻辑推理logical deduction 6.测量土地to measure land，推导定理to deduce theorems，指定的运算indicated operation，获得结论to obtain the conclusions，占据中心地位to occupy the centric place 汉译英 （1）数学来源于人类的社会实践，包括工农业的劳动，商业、军事和科学技术研究等活动。 Mathematics comes from man’s social practice, for example, industrial and agricultural production, commercial activities, military operations and scientific and technological researches. （2）如果没有运用数学，任何一个科学技术分支都不可能正常地发展。 No modern scientific and technological branches could be regularly developed without the application of mathematics. （3）符号在数学中起着非常重要的作用，它常用于表示概念和命题。 Notations are a special and powerful tool of mathematics and are used to express conceptions and propositions very often. （4）17 世纪之前，人们局限于初等数学，即几何、三角和代数，那时只考虑常数。 Before 17th century, man confined himself to the elementary mathematics, i. e. , geometry, trigonometry and algebra, in which only the constants were considered. （5）方程与算数的等式不同在于它含有可以参加运算的未知量。 Equation is different from arithmetic identity in that it contains unknown quantity which can join operations. （6）方程又称为条件等式，因为其中的未知量通常只允许取某些特定的值。Equipment is called an equation of condition in that it is true only for certain values of unknown quantities in it. （7）方程很有用，可以用它来解决许多实际应用问题。
专业英语作业
PART1: Reading How to quickly read an English paper? Metalworking Glossary Cutting Tool Engineering, November, 2000, 209-238 The metalworking glossary defines terms common to those who cut and grind metals and other materials. The terms are divided into 11 categories: 1.Manufacturing Definitions; 2.Machining Operations; 3.Machine Tools and Ancillary Equipment; 4.Cutting Tools and Related Terminology 5.Coolants, Lubricants, and Related Terminology 6.Accessories and Attachments; 7.Alloys, Coatings, Material Compositions, and Related Terminology; 8.Heat-treating and Special Processes; 9.Inspection, Measurement, and Quality Control; 10.Robotics and Automated Assembly; 11.Nontraditional Machining How to Make Use of the Linguistic Features of Scientific Papers (科技论文的语言特点) 1.Linguistic Style(语体) 科学技术领域，科技工作者的任务： 描述自然现象 分析自然现象产生的规律 研究自然现象应用于人类生产实践 的方法 表达所取得的成果及其应用 思维形式：概念、公式或公式化的概念 思维活动的语言表达：按照严格的逻辑程序导 出的判断和推理，科技文体具有抽象性、概念 性和高度的逻辑性 内容：写实 语言风格：准确严谨、合乎逻辑，非形象性(理 性)、客观性、无明显感情色彩、简洁明快。Literature 1.Conference paper 2.Journal paper 3.Lecture 4.Book (Dissertation or Thesis) 5.Report (News) 6.Manual and Specification Paper and Experimental Report: Title, Abstract, Introduction, Results and Analysis, Conclusion and Discussion Book & Lecture: Title, Author(s), Name of the process or publisher, Name of the printing House, Name of the distributor, Date of publication, Date of printing, Synopsis, Note by the publisher, International Standard Book Number, Preface or Foreword, Acknowledgements, Contents, Text of the book, Appendix or Supplement, Index, Epilogue Manual and Instructions, Directions: Principle, Operation, Maintenance 2.Vocabulary Typically Professionalized Terms Whenever a force acts on a body so as to make the body move through some distance, it is said to have done work. Body n. 身体, 肉体, 人, 尸体, 主要部分, 团体, 大量vt. 赋以形体 机械专业n. 车身,机身