专业英语作业

专业英语作业

5.3.1

Control requirements

Whether the application involves continuous control, discrete control, or both, there are certain basic requirements that tend to be common to nearly all process control applications. By and large , they are concerned with the need to communicate and interact with the process on a real-time basis. A real-time controller is a controller that is able to respond to the process within a short enough time period that process performance is not degraded. Real-time control usually requires the controller to be capable of multitasking, which means coping with multiple tasks concurrently without the tasks interfering with one another.

There are two basis requirements that must be managed by the controller to achieve real-time control:

1.Process-initiated interrupts. The controller must be able to

respond to incoming signals from the process. Depending on

the relative importance of the signal, the computer may need

to interrupt execution of a current program to service a higher

priority need of the process. A process-initiated interrupt is

often triggered by abnormal operating conditions, indicating

that some corrective action must be taken promptly.

2.Timer-initiated actions. The controller must be capable of

executing certain actions at specified points in time.

Timer-initiated actions can be generated at regular time

intervals, ranging form very low values (e.g.,100us)to several

minutes, or they can be generated at distinct points in time.

Typical timer-initiated actions in process control include

(1)scanning sensor values form the process at regular

sampling intervals.(2)turning on and off switches, motors,

and other binary devices associated with the process at

discrete points in time during the work cycle,(3)displaying

performance data on the operator’s console at regular times

during a production run, and(4) recomputing optimal process

parameter values at specified times.

These two requirement correspond to the two types of changes mentioned previously in the context of discrete control systems: (1)event-driven changes and (2)time-driven changes.

In addition to these basic requirements, the control computer must also deal with other types of interruptions and events. These include the following :

https://www.sodocs.net/doc/a911627677.html,puter commands to process. In addition to receiving

incoming signal from the process, the control computer must

send control signals to the process to accomplish a corrective

action. These output signal may actuate a certain hardware device or readjust a set point in control loop.

4.System-and program-initiated events. These are events

related to the computer system itself. They are similar to the kinds of computer operations associated with business and engineering applications of computers. A system-initiated event involves communications among computers and peripheral devices linked together in a network. In these multiple computer networks, feedback signals, control commands, and other data must be transferred back and forth among the computers in the overall control of the process. A program-initiated event occurs when the program calls for some non-process-related action, such as the printing or display of reports on a printer or monitor. In process control, system- and program-initiated events generally occupy a low level of priority compared with process interrupts, commands to the process, and timer-initiated events.

5.operator-initiated events. Finally, the control computer must

be able to accept input form operating personnel.

Operator-initiated events include (1)entering new programs;

(2)editing existing programs; (3)entering customer data, order

number, or startup instructions for the next production run;

(4)requesting process data; and (5)calling for emergency

stops.

TABLE6.2 Common measuring devices used in automation

7.4.3Advantages and Disadvantage of NC

When the production application satisfies the characteristics identified in section 7.4.1, NC yields many advantages over manual production methods. These advantages translate into economic savings for the user company. However, NC involves more sophisticated technology than conventional production methods, and there are costs that must be considered to apply the technology effectively. In this section, we examine the advantages and disadvantages of NC. Advantages of NC. The advantages generally attributed to NC, with emphasis on machine tool applications, are the following:

Nonproductive time is reduced.NC cannot optimize the metal cutting process itself, but it

can reduce the proportion of time the machine is not cutting metal. Reduction in noncutting

time is achieved through fewer setups, less setup time, reduced

work-piece handing time, and

automatic tool changes on some NC machines. This advantage translates into labor cost

saving and lower elapsed times to produce parts.

Greater accuracy and repeatability. Compared with manual production methods, NC reduces

or eliminates variations that are due to operator skill differences, fatigue, and other factors

attributed to inherent human variabilities. Parts are made closer to nominal dimensions, and

there is less dimensional variation among parts in the batch.

Lower scrap rates. Because greater accuracy and repeatability are repeatability are achieved,

and because human errors are reduced during production, more parts are produced within

tolerance. As a consequence, a lower scrap allowance can be planned into the production

schedule, so fewer parts are made in each batch with the result production time is saved.

Inspection requirements are reduced.Less inspection is need when NC is used because parts produced from the same NC part program are virtually identical. Once the program has been verified, there is no need for the high level of sampling inspection that is required when parts are produced by conventional manual methods. Except for tool wear and equipment malfunctions, NC produces exact replicates of the part each cycle.

More complex part geometries are possible.NC technology has extended the range of possible part geometries beyond what is practical with manual methods. This is an advantage in product design in several ways:(1) More functional features can be designed into a single into a single part, thus reducing the total number of parts in the product and the associated cost of assembly, (2) mathematically defined surface can be fabricated with high precision, and (3) he limits within which the designer’s imagination can wander to create new part and product geometrics are expanded.

Engineering changes can be accommodated more gracefully. Instead of making alterations in a complex fixture so that the part

can be machined to the engineering change, revisions are made in the NC part program to accomplish the change.

Simpler fixtures are needs. NC requires simpler fixtures because accurate positioning of the tool is accomplished by the NC machine tool. Tool positioning does not have to be designed into the jig.

Shorter manufacturing lead times. Jobs can be set up more quickly and fewer setups are required per part when NC is used. This results in shorter elapsed time between order release and completion.

Reduced parts inventory. Because fewer setups are required and job changeovers are easier and faster, NC permits production of parts in smaller lot sizes. The economics lot size is lower in NC than in conventional batch production. Average parts inventory is therefore reduced.

Less floor space required. This results form the fact that fewer NC machine are required to perform the same amount of work compared to the number of conventional machine tools needed. Reduced parts inventory also contributes to lower floor space requirements.

Operator skill-level requirements are reduced. Workers need fewer skill to operate an NC machine than to operate a conventional machine tool. Tending an NC machine tool usually consists only of loading and unloading parts and periodically changing tools. The machining cycle is carried out under program control. Performing a comparable machining cycle on a conventional machine requires much more participation by the operator, and a higher level of training and skill.

Disadvantages of NC. There are certain commitments to NC technology than must be made by the machine shop that installs NC equipments, and these commitments most of which involve additional cost to the company, might be seen as disadvantages. The disadvantages of NC include the following:

High investment cost. An NC machine tool has a higher first cost than a comparable conventional machine tool. There are several reason why: (1) NC machines include CNC controls and electronics hardware; (2)software development costs of the CNC controls manufacturer must be included in the cost of the machine ;(3)more reliable mechanical components are generally used in NC machines; and (4) NC machine tools often possess additional features not

included on conventional machines, such as automatic tool changers and part changers(Section 14.3.3).

Higher maintenance effort. In general, NC equipment requires more maintenance than conventional equipment, which translates to higher maintenance and repair costs. This is due largely to the computer and other electronics that are included in a modern NC system. The maintenance staff must include personal who are trained in maintaining and repairing this type of equipment.

Part programming. NC equipment must be programmed. To be fair, it should be mentioned that process planning must be accomplished for any part, whether or not it is produced on NC equipment. However, NC part programming is a special preparation step in batch production that is absent in conventional machine shop operations.

Higher utilization of NC equipment. To maximize the economic benefits of an NC machine tool, it usually must be operated for multiple shifts. This might mean adding one or two extra shifts to the plant’s normal operations, with the requirement for supervision and other staff support.

8.4

SENSORS IN ROBOTICS

The general topic of sensors as components in controls systems was discussed in Chapter6 (Section 6.1).Here we discuss sensors as they are applied in robotics. Sensors used in industrial robotic can be classified into two categories: (1)internal and(2)external. .Internal sensors are components of the robot and are used to control the positions and velocities of the various joints of the robot. These sensors form a feedback control loop with the robot controller. Typical sensors used to control the position of the robot arm include potentiometers and optical encoders. Tachometers of various types

are used to control the speed of the robot arm.

External sensors are external to the robot and are used to coordinate the operation of the robot with the other equipment in the cell. In many cases, these external sensors are relatively simple devices, such as limit switches that determine whether a part has been positioned properly in a fixture or that a part is ready to be picked up at a conveyor . Other situations require more advanced sensors technologies, including the following:

●Tactile sensors. These are used to determine whether is

made between the sensors and other object. Tactile sensors

can be divided into two types in robot applications: (1)

touch sensors and (2) force sensors. Touch sensors indicate

simply that contact has been made with the object. Force

sensors indicate the magnitude of the force with the object.

This might be useful in a gripper to measure and control

the force being applied to grasp a delicate object

●Proximity sensors. These indicate when an object is close

to the sensors. When this type of sensors is used to

indicate the actual distance of the object, it is called a range

sensor.

●Optical sensors. Photocells and other photometric devices

can be utilized to detect presence and absence of objects

and are often used for proximity detection.

●Machine vision. Machine vision is used in robotic for

inspection, parts identification, guidance, and other uses. In

Section 22.6, we provide a more complete discussion of

machine vision in automated inspection. Improvements in

programming of vision-guided robot(VGR)systems have

made implementations of this technology easier and

faster[12].

●Other sensors. A miscellaneous category includes other

types of sensors that might be used in robotic, such as

devices for measuring temperature, fluid pressure, fluid

flow, electrical voltage, current, and various other physical

properties.

9.3.1 Components of the PLC

A schematic diagram of a PLC is presented in Figure 9.13. The basic components of the PLC are following: (1) processor, (2) memory unit, (3) power supply, (4) I/O module, and (5) programming device.

These components are housed in a suitable cabinet designed for the industrial environment.

The processor is the central processing unit(CPU) of the programmable controller. It executes the various logic and sequencing functions by operating on the PLC inputs to determine the appropriate output signals. The typical CPU operating cycle is described in Section 9.3.2. The CPU consists of one or more microprocessors similar to those used in PCs and other data processing equipment. The difference is that they have a real-time operating system and are programmed to facilitate I/O transactions and execute ladder logic functions. In addition, PLCs are hardened so that the CPU and other electronic components will operate in the electrically noisy environment of the factory.

Connected to the CPU is the PLC memory unit, which contains the programs of logic, sequencing, and I/O operations. It also holds data files associated with these programs, including I/O status bits, counter and timer constants, and other variable and parameter values. This memory unit is referred to as the user or application memory because its contents are entered by the user. In addition, the processor also contains the operating system memory, which directs

the execution of the control program and coordinates I/O operations. The operating system is entered by the PLC manufacturer and cannot be accessed or altered by the user.

A power supply of 115V ac is typically used to drive the PLC(some units operate in 230V ac). The power supply converts the 115V ac into direct current (dc) voltages of ±5V. These low voltages are used to operate equipment that may have much higher voltage and power ratings than the PLC itself. The power supply often includes a battery backup that switches on automatically in the event of an external power source failure.

The input/output module provides the connections to the industrial equipment or process that is to be controlled. Inputs to the controller are signals from limit switches, push-buttons, sensors, and other on/off devices. Outputs from the controller are an/off signals to operate motors, values, and other devices required to actuate the process. In addition, may PLCs are capable of accepting continuous signals from analog sensors and generating signals suitable for analog actuators. The size of a PLC is usually rated in terms of the number of its I/O terminals, as indicated Table 9.8.

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.

专业英语作业—15

Reading Material 15 阅读材料15 Chemical Industry and Environmental Protection 化学工业与环境保护 How can we reduce the amount of waste that is produced? And how we close the loop by redirecting spent materials and products into programs of recycling? All of these questions must be answered through careful research in the coming years as we strive to keep civilization in balance with nature. 我们怎么样才能够减少化学工业产生的污染物的排放，怎么才能够使材料的产品更好地循环利用，为了自然生态的平衡，所有这些问题都是下来我们必须通过认真的研究和探索来解决的问题。 1. Life Cycle Analysis 1.生命循环的分析 Every stage of a product’s life cycle has an environmental impact, starting extraction of raw materials, continuing through processing, manufacturing, and transportation, and concluding with consumption and disposal or recovery. Technology and chemical science are challenged at every stage. Redesigning products and processes to minimize environmental impact requires a new philosophy of production and a different level of understanding of chemical transformations. Environment friendly products require novel materials that are reusable, recyclable, or biodegradable; properties of the materials are determined by the chemical composition and structure. To minimize waste and polluting by-products, new kinds of chemical process schemes will have to be developed. Improved chemical separation techniques are needed to enhance efficiency and remove residual pollutants, which in turn will require new chemical treatment methods in order to render them harmless. Pollutants such as radioactive elements and toxic heavy metals that cannot be readily converted into harmless materials will need to be immobilized in inert materials so that can be safely stored. Finally, the leftover pollution of an earlier, less environmentally aware era demands improved chemical and biological remediation techniques. 每一个时代的产品的循环利用对环境都有着重大的影响，力争选用天然的材料，继续通过加工，制造，运输，总结与消费和处置或回收。生化科学技术在每一个领域都是充满着挑战的，为使产品对环境的影响降至而重新设计产品或工艺过程，而要一种环保的产品的全新理念和对生化降解作用更高水平的理解。一种环保的产品应该是由一种全新的材料做成的，并且这种新型的材料是可以重新回收利用的，或可以被生物降解的。材料的这一特性是由其化学的组分和分子结构所决定的，为了将产品所带来的污染和废弃物降至最低，我们必须找到更新的化学工艺方法，提高化学分离技术对分离污染是必须的，有效的。这本身就是需要更新，更好的化学处理方法来保证。像这类并不能转变为无害的污染，如放射源污染和重金属污染。我们必须使他们固定储存在金属盒子里面。这样，他们才是安全的。最后，更早，无意识时所造成的残佘物污染，就需要生化技术来补救解决了。 2. Manufacturing with Minimal Environmental Impact 2.对环境影响最小的生产制造 Discharge of waste chemicals to the air, water, or ground not only has a direct environmental impact, but also constitutes a potential waste resources. Early efforts to lessen

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/a911627677.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

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管理英语4 答案 Unit1 test 一、选择填空题（每题10分，共5题） 题目1 — We could let some of the staff work from home.________________?— That's a good idea. 正确答案是：What do you think of it 题目2 — Is it possible for you to work out the plan tonight? —__________ 正确答案是：I think so. 题目3 ______ his anger the employees called him Mr. Thunder, but they loved him.正确答案是：Due to 题目4

It is through enthusiasm and quiet intensity ______ we transform creativity and vision into the technologies. 正确答案是：that 题目5 ______ CEOs spend planning, the more profitable their companies are. 正确答案是：The more time 题目6 — This project is too big for me to finish on time. —________________. 正确答案是：I'll give you a hand 题目7 — I think things have been a bit difficult for us the last couple of months. —__________. We've been working hard, but still getting behind. 正确答案是：You're right 题目8

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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

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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