计算机外文翻译--Internet(完整)
毕业设计(论文)外文资料翻译
专业：计算机科学与技术
姓名：周喜民
学号：06120132
外文出处：The History of the Internet
附件： 1.外文资料翻译译文；2.外文原文。
指导教师评语：
签名：
2008年4月3日
附件1：外文资料翻译译文
Internet的历史
起源——ARPAnet
Internet是被美国政府作为一项工程进行开发的。这项工程的目的，是为了建立远距离之间点与点的通信，以便处理国家军事范围内的紧急事件，例如核战争。这项工程被命名为ARPAnet，它就是Internet的前身。建立此工程的主要应用对象就是军事通讯，那些负责ARPAnet的工程师们当时也没有想到它将成为“Internet”。
根据定义，一个“Internet”应该由四或者更多的计算机连接起来的网络。
ARPAnet是通过一种叫TCP/IP的协议实现连网工作的。此协议最基础的工作原理是：如果信息在网络中的一条路径发送失败，那么它将找到其他路径进行发送，就好象建立一种语言以便一台计算机与其他计算机“交谈”一样，但不注意它是PC，或是Macintosh。
到了20世纪80年代，ARPAnet已经开始变成目前更为有名的Internet了，它拥有200台在线主机。国防部很满意ARPAnets的成果，于是决定全力将它培养为能够联系很多军事主机，资源共享的服务网络。到了1984年，它就已经超过1000台主机在线了。
在1986年ARPAnet关闭了，但仅仅是建立它的机构关闭了，而网络继续存在与超过1000台的主机之间。由于使用NSF连接失败，ARPAnet才被关闭。NSF是将5个国家范围内的超级计算机连入ARPAnet。
随着NSF的建立，新的高速的传输介质被成功的使用，在1988年，用户能通过56k的电话线上网。在那个时候有28，174台主机连入Internet。到了1989年有80，000台主机连入Internet。到1989年末，就有290，000台主机连入了。
另外还有其他网络被建立，并支持用户以惊人的数量接入。于1992年正式建立。
现状——Internet
如今，Internet已经成为人类历史上最先进技术的一种。每个人都想“上网”去体验一下Internet中的信息财富。成千上百的人都用Internet。预计，到了2003年世界上的每个人，都将拥有Internet接入。Internet已经真正成为我们这个年代生活的一部分。由于计算机技术和网络技术每天都在改变，我们很难想象
Internet下一步将发展成什么样子。
工作原理：
现在，人们用Internet是一件很平常的事。他们通过Internet进行购物、玩游戏、聊天等娱乐活动。
Internet不仅仅是一件事物。Internet也会崩溃。它的工作原理如同电话通信系统，只不过没有专门的Internet公司来经营Internet。
Internet是成千上万台计算机互相连接的集合。Internet就像是办公网络一样，不同的是，它有成千上万台计算机相连接。
其中最主要的是Internet是如何进行通信的。位于Houston的一台计算机是如何通过浏览网页而能与位于Tokyo的计算机进行数据通信的呢？
Internet信息，拥有信息的计算机连接到Internet，是基于语言。这种语言叫做TCP/IP。TCP/IP建立了一种语言，能使计算机在Internet系统中传送数据。
但是TCP/IP的取得也必须具备两台电脑之间的物理连接。当然也未必都是这样。但也必须存在一根网络线将主机与Internet连接起来，但做到这样，还是不可能与Internet连接的。
物理连接要求通过MODEM，电话线和其他类似MODEM的连接（如DSL）来建立。计算机上的MODEM通过已建立的通信线进行收发数据，通信线可以是电话线或是数据线。事实上计算机之间建立连接的硬核被成为路由器。
路由器就是计算机中进行信息交互的管理器。
为了更好的对它说明，让我们来看看一台标准的计算机是怎样浏览网页的？
1、用户计算机拨号进入ISP。而此ISP可能还要连接入其他ISP，或是直接进入Internet主干。
2、用户打开网页浏览器如NETSCAPE或是IE。
3、接下来是进入Internet的棘手部分。首先，用户计算机相路由器发出请求。路由器是一种高速高效的计算机运行的专门软件。世界上所有路由的连接便形成了Internet的主干，在这里传送Internet上的所有数据。目前主干网上的处理速度为每秒几千兆字节。这样的速度分配到一只MODEM上，就好比太阳光的热量分配到一块冰上的热量一样。
4、路由器发送或接受数据。它将一小段数据分别打包，形成数据报，就像包裹一样。因此，当请求网页浏览是，就用TCP/IP协议告诉路由器如何处理这些数
据，将这些数据发送去哪里，用户主要想去哪里。
5、路由器将这些数据报发送给其他的路由器，最终转到目标主机上。就像传耳语的游戏一样（当然，只有完整的信息才能被传送）。
6、当信息到达目标网页的服务器是，服务器就开始将网页信息发送回去。一台网页服务器，就是网页存储所在的计算机，它能对网页进行编辑，并将它发送给用户。网页被分成数据报，通过路由器，最终到达用户计算机，这样，用户就能浏览网页了。数据报中含有相关的数据以及一些必须的信息让路由器或其他计算机知道如何将数据报按正确的顺序重新组装成原始的数据段。
有了成千上万的网页和成千上万的用户，对于初学者来说使用Internet将不再那么容易，尤其是那些不太精通电脑的人。接下来，你将能找到一些上网的小技巧和使用Internet主要服务的帮助。
在你打开网页之前，你必须有一个网页浏览器用于浏览网页。大部分网络服务商都会给用户提供一个网络浏览器。当你在浏览网页时，其实就是在使用浏览器。目前使用最广泛的网页浏览器是Netscape和MSIE。Netscape能自动连接到https://www.360docs.net/doc/406614944.html,，MSIE能自动连接https://www.360docs.net/doc/406614944.html,。
接下来你就必须熟悉如何使用网页。网页是超链接、图片、文本、表格、按钮以及多媒体的集合。只需点击网页提供的连接或是按照网页的步骤（比如，如果你需要用网页中的一张表，旁边就会有使用这张表的帮助）做，你就可以进行网上冲浪了。基本上，网页中的每个元素都可以自我移植。
“哦，不！又是404出错！‘不能找到相关网页’”这是上网初学者中很普通的言论。
有时网站也会出错。当然网站的错误跟用户的操作没有关系。
404出错意思是你想找的那个网页不存在。这有可能是因为网站仍在建设中，页面还没有被创建，或者是因为网站的制作者正在对页面进行修改。当出现404出错时，除了对网站管理发电子邮件，告诉他/她关于出错的问题，就别无他法了。
Javascript出错是由于网站中的Javascript的程序代码出错造成的。并非所有的网页都使用Javascript，但有很多是用Javascript的。Javascript不同于JAVA，目前大部分浏览器都支持Javascript。如果你现在用的是旧版的网页浏览器，那么就有可能出现Javascript出错，那是因为你的浏览器的版本低于站点使用的Javascript版本。所以，你应该为你的浏览器升级到新的版本。
电子邮件即电子方式的邮件。电子邮件能使人们互相收发信件，甚至是文件和图片。
要使用电子邮件，那你就必须拥有一个电子邮件客户端，它就像是邮递员，为你收发电子邮件。
其次，你必须有一个电子邮件帐户。大部分网络服务供应商都会提供给用户一个免费的电子邮件帐户。有的网站也提供免费的电子邮箱，如Hotmail和Geocities。
配置好电子邮件客户端，包括POP3和SMTP服务器地址（电子邮件供应商会给你相关信息）之后，你就可以准备收邮件了。
附件是与信一起发过来的文件，如果有人发给你带有附件的邮件，但你不知道他是谁，就不要打开那个附件。它有可能是病毒或是其他恶意的程序。用户不会通过阅读邮件而被传染病毒，你不得不运行杀毒软件来防止病毒感染。
签名是很多电子邮件程序的一个特征。签名加在邮件的末尾。你可以将生动的文本，你职业信息或是其他你喜欢的东西作为签名。
设想在国际互联网中的电脑就像海中的岛屿。那么海洋中就充满了数百万的岛屿。这就是国际互联网。设想岛与岛之间是通过发送和接收船只来联络的。那么岛屿就有接收和发送船只的港口。
在国际互联网中的电脑有被叫做“港口”的端口。端口只是一个象征性的对象，它使得电脑能在网络（或是国际互联网）上运转。这种方法与上面提到的“岛屿、海洋”形象论类似。
远程登陆涉及到在服务器上直接用文本连接来使用端口。
几乎每种互联网活动，如访问网页、聊天、以及发电子邮件都是依托远程登陆来实现的。
远程登陆需要一个远程登陆客户服务器。远程登陆程序兼容于Windows系统，所以Windows用户可以通过在对话窗口键入telnet（不加's）来接入远程登陆软件。Linux系统则将它创建在命令行里：键入telnet。用于Macintosh的普通远程登陆程序是NCSA远程登陆软件。
任何一个服务软件（网页端口监督程序，聊天端口监督程序）都可以通过远程登陆被接入，即使这些软件不经常以这种方法被接入。
举例来说，直接与邮件服务器连接并通过与邮件服务软件交流来校对你的邮件是可能的，但用电子邮件客户服务器却更简单（当然如此）。
世界各地有数百万的网页，那么你如何知道哪个网页的地址是你需要的呢？
搜索工具能节约时间。搜索工具是一个非常庞大的网站，它使你能够搜寻它自有的网站数据库。
举例来说，如果你要找关于“狗”的网站，你可以搜索“狗”或“狗的信息”。这里有一些搜索引擎：
1.Altavista(https://www.360docs.net/doc/406614944.html,)-Web spider&Indexed
2.Yahoo(https://www.360docs.net/doc/406614944.html,)-Web spider&Indexed Collection
3.Excite(https://www.360docs.net/doc/406614944.html,)-Web spider&Indexed
4.Lycos(https://www.360docs.net/doc/406614944.html,)-Web spider&Indexed
5.Metasearch(https://www.360docs.net/doc/406614944.html,)-Multiple search
网络蜘蛛是一种搜索引擎使用的程序，它随着可能找到的任何链接从一个网页到另一个网页。
这意味着只要它自己的时间和速度允许，搜索引擎就能尽可能多地在网络上逐字搜寻信息。编入索引的收集使用手动附加链接。比如雅虎网站。你可以点击“电脑和网络”，再点击“硬件”，然后点击“猫”（调制解调器）等等。那么通过分类的过程，与你要的类别相关的网站就找到了。
Metasearch同时搜索许多搜索引擎，从十个引擎中找出最上面的搜索结果，使得搜索变得有效很多。一旦你能够使用搜索引擎，你就能有效的找到你要的网页。伴随着网络系统和多用户系统时代的来临，安全总是系统开发和系统操作人员考虑的问题。
从美国电报电话公司和它的电话网组建开始，黑客已为许多人所知。黑客就是一直寻找途径侵入系统的人。这过去不是一个大问题，因为网络系统对于那些能够提供必要的电脑安全措施的大型法人公司和政府的电脑来说是有限的。
现今最大的问题是个人信息。为什么当你通过网络购物时应该小心？让我们快速地看一看国际互联网时如何工作的。用户将信用卡的信息传递到网页上。看起来安全，对吗？其实未必。当用户提交信息时，它就会流过组成互联网主干网的一系列的电脑。信息是小块的一包包的，被称作信息包。
这里有个问题：当信息通过这巨大的支柱被传递时，怎样防止黑客在支柱的某一点上拦截数据流？你接入网站时哥哥不会看着你，但用户在传递私人信息时应该清楚潜在的威胁。
加强安全有很多方法，如密码保护，一种最重要的措施：加密。加密指将数据搅乱成只能在另一终端才能译出的密码。像Netscape Communicator和Internet Explore这样的浏览器为在线传递提供了特色的加密支持。
一些加密措施比其他工作地更好。最先进的加密系统被称作DES（数据加密准则），且它被美国安全局采纳，因为它被认为是如此难以非法侵入以至他们认为如果它落入其它国家手中会有安全风险。
DES用单独的信息钥匙来开启一整个文件。问题是有75万亿可能的钥匙可用，所以它是一个很难破坏的系统。一个文件被侵入并被解码，但这是一个需14000台电脑进入互联网系统的综合的努力过程，并需要花一段时间来做。所以大部分黑客没有那么多的资源。
附件2：外文原文
The History of the Internet
The Beginning-ARPAnet
The Internet started as a project by the US government.The object of the project was to create a means of communications between long distance points,in the event of a nation wide emergency or,more specifically, nuclear war.The project was called ARPAnet,and it is what the Internet started as.Funded specifically for military communication,the engineers responsible for ARPANet had no idea of the possibilities of an"Internet."
By definition,an'Internet'is four or more computers connected by a network.
ARPAnet achieved its network by using a protocol called TCP/IP.The basics around this protocol was that if information sent over a network failed to get through on one route,it would find another route to work with,as well as establishing a means for one computer to"talk"to another computer, regardless of whether it was a PC or a Macintosh.
By the80's ARPAnet,just years away from becoming the more well known Internet,had200computers.The Defense Department,satisfied with ARPAnets results,decided to fully adopt it into service,and connected many military computers and resources into the network.ARPAnet then had562computers on its network.By the year1984,it had over1000computers on its network.
In1986ARPAnet(supposedly)shut down,but only the organization shut down,and the existing networks still existed between the more than1000 computers.It shut down due to a failied link up with NSF,who wanted to connect its5countywide super computers into ARPAnet.
With the funding of NSF,new high speed lines were successfully installed at line speeds of56k(a normal modem nowadays)through telephone lines in1988.By that time,there were28,174computers on the(by then decided) Internet.In1989there were80,000computers on it.By1989,there were
290,000.
Another network was built to support the incredible number of people joining.It was constructed in1992.
Today-The Internet
Today,the Internet has become one of the most important technological advancements in the history of humanity.Everyone wants to get'on line' to experience the wealth of information of the https://www.360docs.net/doc/406614944.html,lions of people now use the Internet,and it's predicted that by the year2003every single person on the planet will have Internet access.The Internet has truly become a way of life in our time and era,and is evolving so quickly its hard to determine where it will go next,as computer and network technology improve every day.
HOW IT WORKS:
It's a standard thing.People using the Internet.Shopping,playing games,conversing in virtual Internet environments.
The Internet is not a'thing'itself.The Internet cannot just"crash." It functions the same way as the telephone system,only there is no Internet company that runs the Internet.
The Internet is a collection of millioins of computers that are all connected to each other,or have the means to connect to each other.The Internet is just like an office network,only it has millions of computers connected to it.
The main thing about how the Internet works is communication.How does a computer in Houston know how to access data on a computer in Tokyo to view a webpage?
Internet communication,communication among computers connected to the Internet,is based on a language.This language is called TCP/IP.TCP/IP establishes a language for a computer to access and transmit data over the Internet system.
But TCP/IP assumes that there is a physical connecetion between one
computer and another.This is not usually the case.There would have to be a network wire that went to every computer connected to the Internet,but that would make the Internet impossible to access.
The physical connection that is requireed is established by way of modems,phonelines,and other modem cable connections(like cable modems or DSL).Modems on computers read and transmit data over established lines,which could be phonelines or data lines.The actual hard core connections are established among computers called routers.
A router is a computer that serves as a traffic controller for information.
To explain this better,let's look at how a standard computer might view
a webpage.
1.The user's computer dials into an Internet Service Provider(ISP). The ISP might in turn be connected to another ISP,or a straight connection into the Internet backbone.
2.The user launches a web browser like Netscape or Internet Explorer and types in an internet location to go to.
3.Here's where the tricky part comes in.First,the computer sends data about it's data request to a router.A router is a very high speed powerful computer running special software.The collection of routers in the world make what is called a"backbone,"on which all the data on the Internet is transferred.The backbone presently operates at a speed of several gigabytes per-second.Such a speed compared to a normal modem is like comparing the heat of the sun to the heat of an ice-cube.
Routers handle data that is going back and forth.A router puts small chunks of data into packages called packets,which function similarly to envelopes.So,when the request for the webpage goes through,it uses TCP/IP protocols to tell the router what to do with the data,where it's going, and overall where the user wants to go.
4.The router sends these packets to other routers,eventually leading
to the target computer.It's like whisper down the lane(only the information remains intact).
5.When the information reaches the target web server,the webserver then begins to send the web page back.A webserver is the computer where the webpage is stored that is running a program that handles requests for the webpage and sends the webpage to whoever wants to see it.
6.The webpage is put in packets,sent through routers,and arrive at the users computer where the user can view the webpage once it is assembled.
The packets which contain the data also contain special information that lets routers and other computers know how to reassemble the data in the right order.
With millions of web pages,and millions of users,using the Internet is not always easy for a beginning user,especially for someone who is not entirely comfortale with using computers.Below you can find tips tricks and help on how to use main services of the Internet.
Before you access webpages,you must have a web browser to actually be able to view the webpages.Most Internet Access Providers provide you with a web browser in the software they usually give to customers;you.The fact that you are viewing this page means that you have a web browser.The top two use browsers are Netscape Communicator and Microsoft Internet Explorer. Netscape can be found at https://www.360docs.net/doc/406614944.html, and MSIE can be found at https://www.360docs.net/doc/406614944.html,/ie.
The fact that you're reading this right now means that you have a web browser.
Next you must be familiar with actually using webpages.A webpage is a collection of hyperlinks,images,text,forms,menus,and multimedia.To "navigate"a webpage,simply click the links it provides or follow it's own instructions(like if it has a form you need to use,it will probably instruct you how to use it).Basically,everything about a webpage is made to be self-explanetory.That is the nature of a webpage,to be easily navigatable.
"Oh no!a404error!'Cannot find web page?'"is a common remark made by new web-users.
Sometimes websites have errors.But an error on a website is not the user's fault,of course.
A404error means that the page you tried to go to does not exist.This could be because the site is still being constructed and the page hasn't been created yet,or because the site author made a typo in the page.There's nothing much to do about a404error except for e-mailing the site administrator(of the page you wanted to go to)an telling him/her about the error.
A Javascript error is the result of a programming error in the Javascript code of a website.Not all websites utilize Javascript,but many do. Javascript is different from Java,and most browsers now support Javascript. If you are using an old version of a web browser(Netscape3.0for example), you might get Javascript errors because sites utilize Javascript versions that your browser does not support.So,you can try getting a newer version of your web browser.
E-mail stands for Electronic Mail,and that's what it is.E-mail enables people to send letters,and even files and pictures to each other.
To use e-mail,you must have an e-mail client,which is just like a personal post office,since it retrieves and stores e-mail.
Secondly,you must have an e-mail account.Most Internet Service Providers provide free e-mail account(s)for free.Some services offer free e-mail,like Hotmail,and Geocities.
After configuring your e-mail client with your POP3and SMTP server address(your e-mail provider will give you that information),you are ready to receive mail.
An attachment is a file sent in a letter.If someone sends you an attachment and you don't know who it is,don't run the file,ever.It could be a virus or some other kind of nasty programs.You can't get a virus just
by reading e-mail,you'll have to physically execute some form of program for a virus to strike.
A signature is a feature of many e-mail programs.A signature is added to the end of every e-mail you send out.You can put a text graphic,your business information,anything you want.
Imagine that a computer on the Internet is an island in the sea.The sea is filled with millions of islands.This is the Internet.Imagine an island communicates with other island by sending ships to other islands and receiving ships.The island has ports to accept and send out ships.
A computer on the Internet has access nodes called ports.A port is just a symbolic object that allows the computer to operate on a network(or the Internet).This method is similar to the island/ocean symbolism above.
Telnet refers to accessing ports on a server directly with a text connection.Almost every kind of Internet function,like accessing web pages,"chatting,"and e-mailing is done over a Telnet connection.
Telnetting requires a Telnet client.A telnet program comes with the Windows system,so Windows users can access telnet by typing in"telnet" (without the"'s)in the run dialog.Linux has it built into the command line;telnet.A popular telnet program for Macintosh is NCSA telnet.
Any server software(web page daemon,chat daemon)can be accessed via telnet,although they are not usually meant to be accessed in such a manner. For instance,it is possible to connect directly to a mail server and check your mail by interfacing with the e-mail server software,but it's easier to use an e-mail client(of course).
There are millions of WebPages that come from all over the world,yet how will you know what the address of a page you want is?
Search engines save the day.A search engine is a very large website that allows you to search it's own database of websites.For instance,if you wanted to find a website on dogs,you'd search for"dog"or"dogs"or"dog information."Here are a few search-engines.
1.Altavista(https://www.360docs.net/doc/406614944.html,)-Web spider&Indexed
2.Yahoo(https://www.360docs.net/doc/406614944.html,)-Web spider&Indexed Collection
3.Excite(https://www.360docs.net/doc/406614944.html,)-Web spider&Indexed
4.Lycos(https://www.360docs.net/doc/406614944.html,)-Web spider&Indexed
5.Metasearch(https://www.360docs.net/doc/406614944.html,)-Multiple search
A web spider is a program used by search engines that goes from page to page,following any link it can possibly find.This means that a search engine can literally map out as much of the Internet as it's own time and speed allows for.
An indexed collection uses hand-added links.For instance,on Yahoo's site.You can click on Computers&the Internet.Then you can click on Hardware.Then you can click on Modems,etc.,and along the way through sections,there are sites available which relate to what section you're in.
Metasearch searches many search engines at the same time,finding the top choices from about10search engines,making searching a lot more effective.
Once you are able to use search engines,you can effectively find the pages you want.
With the arrival of networking and multi user systems,security has always been on the mind of system developers and system operators.Since the dawn of AT&T and its phone network,hackers have been known by many,hackers who find ways all the time of breaking into systems.It used to not be that big of a problem,since networking was limited to big corporate companies or government computers who could afford the necessary computer security.
The biggest problem now-a-days is personal information.Why should you be careful while making purchases via a website?Let's look at how the internet works,quickly.
The user is transferring credit card information to a webpage.Looks safe, right?Not necessarily.As the user submits the information,it is being streamed through a series of computers that make up the Internet backbone.
The information is in little chunks,in packages called packets.Here's the problem:While the information is being transferred through this big backbone,what is preventing a"hacker"from intercepting this data stream at one of the backbone points?
Big-brother is not watching you if you access a web site,but users should be aware of potential threats while transmitting private information.There are methods of enforcing security,like password protection,an most importantly,encryption.
Encryption means scrambling data into a code that can only be unscrambled on the"other end."Browser's like Netscape Communicator and Internet Explorer feature encryption support for making on-line transfers.Some encryptions work better than others.The most advanced encryption system is called DES(Data Encryption Standard),and it was adopted by the US Defense Department because it was deemed so difficult to'crack'that they considered it a security risk if it would fall into another countries hands.
A DES uses a single key of information to unlock an entire document.The problem is,there are75trillion possible keys to use,so it is a highly difficult system to break.One document was cracked and decoded,but it was a combined effort of14,000computers networked over the Internet that took a while to do it,so most hackers don't have that many resources available.
变速器论文中英文对照资料外文翻译文献
中英文对照外文翻译 汽车变速器设计 我们知道，汽车发动机在一定的转速下能够达到最好的状态，此时发出的功率比较大，燃油经济性也比较好。因此，我们希望发动机总是在最好的状态下工作。但是，汽车在使用的时候需要有不同的速度，这样就产生了矛盾。这个矛盾要通过变速器来解决。 汽车变速器的作用用一句话概括，就叫做变速变扭，即增速减扭或减速增扭。为什么减速可以增扭，而增速又要减扭呢？设发动机输出的功率不变，功率可以表示为 N = w T，其中w是转动的角速度，T 是扭距。当N固定的时候，w与T是成反比的。所以增速必减扭，减速必增扭。汽车变速器齿轮传动就根据变速变扭的原理，分成各个档位对应不同的传动比，以适应不同的运行状况。 一般的手动变速器内设置输入轴、中间轴和输出轴，又称三轴式，另外还有倒档轴。三轴式是变速器的主体结构，输入轴的转速也就是发动机的转速，输出轴转速则是中间轴与输出轴之间不同齿轮啮合所产生的转速。不同的齿轮啮合就有不同的传动比，也就有了不同的转速。例如郑州日产ZN6481W2G型SUV车手动变速器，它的传动比分别是：1档3.704:１；2档2.202:1；3档1.414:1；4档1:1；5档（超速档）0.802:1。 当汽车启动司机选择1档时，拨叉将1/2档同步器向后接合1档
齿轮并将它锁定输出轴上，动力经输入轴、中间轴和输出轴上的1档齿轮，1档齿轮带动输出轴，输出轴将动力传递到传动轴上（红色箭头）。典型1档变速齿轮传动比是3:1,也就是说输入轴转3圈，输出轴转1圈。 当汽车增速司机选择2档时，拨叉将1/2档同步器与1档分离后接合2档齿轮并锁定输出轴上，动力传递路线相似，所不同的是输出轴上的1档齿轮换成2档齿轮带动输出轴。典型2档变速齿轮传动比是2.2:1，输入轴转2.2圈，输出轴转1圈，比1档转速增加，扭矩降低。 当汽车加油增速司机选择3档时，拨叉使1/2档同步器回到空档位置，又使3/4档同步器移动直至将3档齿轮锁定在输出轴上，使动力可以从轴入轴—中间轴—输出轴上的3档变速齿轮，通过3档变速齿轮带动输出轴。典型3档传动比是1.7:1，输入轴转1.7圈，输出轴转1圈，是进一步的增速。 当汽车加油增速司机选择4档时，拨叉将3/4档同步器脱离3档齿轮直接与输入轴主动齿轮接合，动力直接从输入轴传递到输出轴，此时传动比1:1，即输出轴与输入轴转速一样。由于动力不经中间轴，又称直接档，该档传动比的传动效率最高。汽车多数运行时间都用直接档以达到最好的燃油经济性。 换档时要先进入空档，变速器处于空档时变速齿轮没有锁定在输出轴上，它们不能带动输出轴转动，没有动力输出。 一般汽车手动变速器传动比主要分上述1－4档，通常设计者首先确定最低（1档）与最高（4档）传动比后，中间各档传动比一
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微软Visual Studio 1微软Visual Studio Visual Studio 是微软公司推出的开发环境，Visual Studio可以用来创建Windows平台下的Windows应用程序和网络应用程序，也可以用来创建网络服务、智能设备应用程序和Office 插件。Visual Studio是一个来自微软的集成开发环境IDE，它可以用来开发由微软视窗，视窗手机，Windows CE、.NET框架、.NET精简框架和微软的Silverlight支持的控制台和图形用户界面的应用程序以及Windows窗体应用程序，网站，Web应用程序和网络服务中的本地代码连同托管代码。 Visual Studio包含一个由智能感知和代码重构支持的代码编辑器。集成的调试工作既作为一个源代码级调试器又可以作为一台机器级调试器。其他内置工具包括一个窗体设计的GUI应用程序，网页设计师，类设计师，数据库架构设计师。它有几乎各个层面的插件增强功能，包括增加对支持源代码控制系统（如Subversion和Visual SourceSafe）并添加新的工具集设计和可视化编辑器，如特定于域的语言或用于其他方面的软件开发生命周期的工具（例如Team Foundation Server的客户端：团队资源管理器）。 Visual Studio支持不同的编程语言的服务方式的语言，它允许代码编辑器和调试器（在不同程度上）支持几乎所有的编程语言，提供了一个语言特定服务的存在。内置的语言中包括C/C + +中（通过Visual C++）,https://www.360docs.net/doc/406614944.html,（通过Visual https://www.360docs.net/doc/406614944.html,），C＃中（通过Visual C＃）和F＃（作为Visual Studio 2010），为支持其他语言，如M,Python,和Ruby等，可通过安装单独的语言服务。它也支持的 XML/XSLT,HTML/XHTML ,JavaScript和CSS.为特定用户提供服务的Visual Studio也是存在的：微软Visual Basic，Visual J＃、Visual C＃和Visual C++。 微软提供了“直通车”的Visual Studio 2010组件的Visual Basic和Visual C＃和Visual C + +，和Visual Web Developer版本，不需任何费用。Visual Studio 2010、2008年和2005专业版，以及Visual Studio 2005的特定语言版本（Visual Basic、C++、C＃、J＃），通过微软的下载DreamSpark计划，对学生免费。 2架构 Visual Studio不支持任何编程语言，解决方案或工具本质。相反，它允许插入各种功能。特定的功能是作为一个VS压缩包的代码。安装时，这个功能可以从服务器得到。IDE提供三项服务：SVsSolution，它提供了能够列举的项目和解决方案; SVsUIShell，它提供了窗口和用户界面功能（包括标签，工具栏和工具窗口）和SVsShell，它处理VS压缩包的注册。此外，IDE还可以负责协调和服务之间实现通信。所有的编辑器，设计器，项目类型和其他工具都是VS压缩包存在。Visual Studio 使用COM访问VSPackage。在Visual Studio SDK中还包括了管理软件包框架(MPF)，这是一套管理的允许在写的CLI兼容的语言的任何围绕COM的接口。然而，MPF并不提供所有的Visual Studio COM 功能。
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机械毕业设计英文外文翻译436手动变速器 (2)
附录 附录A. Manual Transmission It’s no secret that cars with manual transmissions are usually more fun to drive than the automatic-equipped counterparts. If you have even a passing interest in the act of driving, then chances are you also appreciate a fine-shifting manual gearbox. But how does a manual transmission actually work? A history hows that manual transmissions preceded automatics by several decades. In fact，up until General Motors offered an automatic in 1938, all cars were of the shift-it-yourself variety. While it’s logical for many types of today’s vehicles to be equipped with an automatic――such as a full-size sedan, SUV or pickup――the fact remains that nothing is more of a thrill to drive than a tautly suspended sport sedan, snort coupe or two-sealer equipped with a precise-shifting five-or six-speed gearbox． We know whicn types or cars have manual trannies. Now let’s take a look at how they work. From the most basic four-speed manual in a car from the’60s to the most high-tech six-speed one in a car of today, the principles of a manual gearbox are the same. The driver must shift from gear to gear. Normally, a manual transmission bolts to a clutch housing (or bell housing）, in turn, bolts to the back of the engine. If the vehicle has front-wheel drive,
计算机专业外文文献翻译6
外文文献翻译（译成中文2000字左右）： As research laboratories become more automated,new problems are arising for laboratory managers.Rarely does a laboratory purchase all of its automation from a single equipment vendor. As a result,managers are forced to spend money training their users on numerous different software packages while purchasing support contracts for each. This suggests a problem of scalability. In the ideal world,managers could use the same software package to control systems of any size; from single instruments such as pipettors or readers to large robotic systems with up to hundreds of instruments. If such a software package existed, managers would only have to train users on one platform and would be able to source software support from a single vendor. If automation software is written to be scalable, it must also be flexible. Having a platform that can control systems of any size is far less valuable if the end user cannot control every device type they need to use. Similarly, if the software cannot connect to the customer’s Laboratory Information Management System (LIMS) database,it is of limited usefulness. The ideal automation software platform must therefore have an open architecture to provide such connectivity. Two strong reasons to automate a laboratory are increased throughput and improved robustness. It does not make sense to purchase high-speed automation if the controlling software does not maximize throughput of the system. The ideal automation software, therefore, would make use of redundant devices in the system to increase throughput. For example, let us assume that a plate-reading step is the slowest task in a given method. It would make that if the system operator connected another identical reader into the system, the controller software should be able to use both readers, cutting the total throughput time of the reading step in half. While resource pooling provides a clear throughput advantage, it can also be used to make the system more robust. For example, if one of the two readers were to experience some sort of error, the controlling software should be smart enough to route all samples to the working reader without taking the entire system offline. Now that one embodiment of an ideal automation control platform has been described let us see how the use of C++ helps achieving this ideal possible. DISCUSSION C++: An Object-Oriented Language Developed in 1983 by BjarneStroustrup of Bell Labs,C++ helped propel the concept of object-oriented programming into the mainstream.The term ‘‘object-oriented programming language’’ is a familiar phrase that has been in use for decades. But what does it mean? And why is it relevant for automation software? Essentially, a language that is object-oriented provides three important programming mechanisms:
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毕业设计(论文)外文资料翻译 系：信息工程学院 专业：计算机科学与技术 姓名： 学号： 外文出处：Chris Haseman. Android-essential (用外文写) s[M].London:Spring--Verlag,2008 .8-13. 附件： 1.外文资料翻译译文；2.外文原文。 指导教师评语： 签名： 年月日注：请将该封面与附件装订成册。
附件1：外文资料翻译译文 无线局域网 一、为何使用无线局域网络 对于局域网络管理主要工作之一，对于铺设电缆或是检查电缆是否断线这种耗时的工作，很容易令人烦躁，也不容易在短时间内找出断线所在。再者，由于配合企业及应用环境不断的更新与发展，原有的企业网络必须配合重新布局，需要重新安装网络线路，虽然电缆本身并不贵，可是请技术人员来配线的成本很高，尤其是老旧的大楼，配线工程费用就更高了。因此，架设无线局域网络就成为最佳解决方案。 二、什么情形需要无线局域网络 无线局域网络绝不是用来替代有限局域网络，而是用来弥补有线局域网络之不足，以达到网络延伸之目的，下列情形可能须要无线局域网络。 ●无固定工作场所的使用者 ●有线局域网络架设受环境限制 ●作为有线局域网络的备用系统 三、无线局域网络存取技术 目前厂商在设计无线局域网络产品时，有相当多种存取设计方式，大致可分为三大类：窄频微波技术、展频(Spread Spectrum)技术、及红外线(Infrared)技术，每种技术皆有其优缺点、限制及比较，接下来是这些技术方法的详细探讨。 1.技术要求 由于无线局域网需要支持高速、突发的数据业务，在室内使用还需要解决多径衰落以及各子网间串扰等问题。具体来说，无线局域网必须实现以下技术要求： 1)可靠性：无线局域网的系统分组丢失率应该低于10-5，误码率应该低 于10-8。
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附录A With the new network technology and application of the continuous rapid development of the computer network should. Use of becoming increasingly widespread, the role played by the increasingly important computer networks and human. More inseparable from the lives of the community's reliance on them will keep growing. In order for computers to communicate, they must speak the same language or protocol. In the early days of networking, networks were disorganized in many ways. Companies developed proprietary network technologies that had great difficulties in exchanging information with other or existing technologies; so network interconnections were very hard to build. To solve this problem, the International Organization for Standardization（ISO）created a network model that helps vendors to create networks compatible with each other. Finding the best software is not easy. A better understanding of what you need and asking the right questions makes it easier. The software should be capable of handling challenges specific to your company. If you operate multiple distribution centers, it may be beneficial to create routes with product originating from more than one depot. Few software providers though, are capable of optimizing routes using multiple depots. The provider should be able to support installation of its product. Make sure to clearly understand what training and software maintenance is offered. Obviously, selecting the right routing/scheduling software is critically important. Unfortunately, some companies are using software that may not be best suited to their operation. Logistics actives with responsibility for approving the software ought to be comfortable they've made the right decision. It is important to realize that not all routing/scheduling software is alike！ There questions to ask are：Which operating system is used？How easy is the software to use？Here is a good way to tell. Ask if its graphical user interface（GUI）is flexible. Find out about installation speed - how long does it take？Is the software able to route third party customers with your core business？When was the software originally released and when was it last upgraded？ In 1984, ISO released the Open Systems Interconnection（OSI）reference model,
二轴式手动变速器外文翻译
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计算机专业外文翻译
专业外文翻译 题目JSP Technology Conspectus and Specialties 系（院）计算机系 专业计算机科学与技术 班级 学生姓名 学号 指导教师 职称讲师 二〇一三年五月十六日
JSP Technology Conspectus and Specialties The JSP (Java Server Pages) technology is used by the Sun micro-system issued by the company to develop dynamic Web application technology. With its easy, cross-platform, in many dynamic Web application programming languages, in a short span of a few years, has formed a complete set of standards, and widely used in electronic commerce, etc. In China, the JSP now also got more extensive attention; get a good development, more and more dynamic website to JSP technology. The related technologies of JSP are briefly introduced. The JSP a simple technology can quickly and with the method of generating Web pages. Use the JSP technology Web page can be easily display dynamic content. The JSP technology are designed to make the construction based on Web applications easier and efficient, and these applications and various Web server, application server, the browser and development tools work together. The JSP technology isn't the only dynamic web technology, also not the first one, in the JSP technology existed before the emergence of several excellent dynamic web technologies, such as CGI, ASP, etc. With the introduction of these technologies under dynamic web technology, the development and the JSP. Technical JSP the development background and development history In web brief history, from a world wide web that most of the network information static on stock transactions evolution to acquisition of an operation and infrastructure. In a variety of applications, may be used for based on Web client, look no restrictions. Based on the browser client applications than traditional based on client/server applications has several advantages. These benefits include almost no limit client access and extremely simplified application deployment and management (to update an application, management personnel only need to change the program on a server, not thousands of installation in client applications). So, the software industry is rapidly to build on the client browser multilayer application. The rapid growth of exquisite based Web application requirements development of
计算机网络外文翻译
附录 一、英文原文： The NetWorks Birth of the Net The Internet has had a relatively brief, but explosive history so far. It grew out of an experiment begun in the 1960's by the U.S. Department of Defense. The DoD wanted to create a computer network that would continue to function in the event of a disaster, such as a nuclear war. If part of the network were damaged or destroyed, the rest of the system still had to work. That network was ARPANET, which linked U.S. scientific and academic researchers. It was the forerunner of today's Internet. In 1985, the National Science Foundation (NSF) created NSFNET, a series of networks for research and education communication. Based on ARPANET protocols, the NSFNET created a national backbone service, provided free to any U.S. research and educational institution. At the same time, regional networks were created to link individual institutions with the national backbone service. NSFNET grew rapidly as people discovered its potential, and as new software applications were created to make access easier. Corporations such as Sprint and MCI began to build their own networks, which they linked to NSFNET. As commercial firms and other regional network providers have taken over the operation of the major Internet arteries, NSF has withdrawn from the backbone business. NSF also coordinated a service called InterNIC, which registered all addresses on the Internet so that data could be routed to the right system. This service has now been taken over by Network Solutions, Inc., in cooperation with NSF. How the Web Works The World Wide Web, the graphical portion of the Internet, is the most popular part of the Internet by far. Once you spend time on the Web,you will begin to feel like there is no limit to what you can discover. The Web allows rich and diverse communication by displaying text, graphics, animation, photos, sound and video. So just what is this miraculous creation? The Web physically consists of your personal computer, web browser software, a connection to an Internet service provider, computers called servers that host digital data and routers and switches to direct the flow of information. The Web is known as a client-server system. Your computer is the client; the remote computers that store electronic files are the servers. Here's how it works: Let's say you want to pay a visit to the the Louvre museum website. First you enter the address or URL of the website in your web browser (more about this shortly). Then your browser requests the web page from the web server that hosts the Louvre's site. The Louvre's server sends the data over the Internet to your computer. Your web
汽车变速器外文翻译
外文翻译 Auto Transmission First, an overview of automotive transmission and the development trend Automobile available more than a century, especially from the mass production of motor vehicles and the automotive industry since the development of large, Car has been the economic development of the world for mankind to enter the modern life and have had a tremendous impact on the immeasurable, The progress of human society has made indelible contributions to the great, epoch-making set off arevolution. From From the vehicle as a power plant using internal combustion engine to start, auto transmission has become an important component. Is Generation is widely used in automotive reciprocating piston internal combustion engine with a small size, light weight, reliable operation and the use of The advantages of convenience, but its torque and speed range of smaller changes, and complex condition requires the use of motor vehicles Traction and the speed can be considerable changes in the scope. Therefore, its performance and vehicle dynamics and economy of There are large inter-contradictions, which contradictions of modern automotive internal combustion engine by itself is insoluble. Because Here, in the automotive power train set up the transmission and main reducer in order to achieve the purpose of deceleration by moment. Speed The main function of performance: ⑴ change gear ratio of motor vehicles, and expand the wheel drive torque and rotational speed of the Fan Wai, in order to adapt to constantly changing driving cycle, while the engine in the most favorable conditions within the scope of work; ⑵no change in the direction of engine rotation, under the premise of the realization of cars driving back; ⑶the realization of the free, temporary Interruption of power transmission, in order to be able to start the engine, idling, etc.. V ariable-speed drive transmission by the manipulation of institutions and agencies. Change the transmission ratio by way of transmission is divided into There are class-type, non-stage and multi-purpose three. Have class most widely used transmission. It uses gear drive, with a number of transmission ratio setting. Stepless transmission Continuously V ariable Transmission (CVT) transmission ratio of a certain The framework of multi-level changes may be unlimited, there is a common type of power and torque (dynamic fluid-type) and so on. Continuously V ariable Transmission Transmission development is the ultimate goal, because only it can make the most economical engine in working condition Can provide the best vehicle fuel economy and optimal power in order to provide the most comfortable By the feeling. Today's CVT is a typical representative of the CVT