計算機英語文章閱讀
❶ 有關於計算機的英語文章嗎帶翻譯的，5000字左右，有的話可以給分
電腦的學名為電子計算機，是由早期的電動計算器發展而來的。1946年，世界上出現了第一台電子數字計算機「ENIAC」，用於計算彈道。是由美國賓夕法尼亞大學莫爾電工學院製造的，但它的體積龐大，佔地面積170多平方米，重量約30噸，消耗近100千瓦的電力。顯然，這樣的計算機成本很高，使用不便。1956年，晶體管電子計算機誕生了，這是第二代電子計算機。只要幾個大一點的櫃子就可將它容下，運算速度也大大地提高了。1959年出現的是第三代集成電路計算機。最初的計算機由約翰·馮·諾依曼發明(那時電腦的計算能力相當於現在的計算器)，有三間庫房那麼大，後逐步發展。 從20世紀70年代開始，這是電腦發展的最新階段。到1970年，由大規模集成電路和超大規模集成電路製成的「克雷一號」，使電腦進入了第四代。超大規模集成電路的發明，使電子計算機不斷向著 小型化、微型化、低功耗、智能化、系統化的方向更新換代。20世紀90年代，電腦向「智能」方向發展，製造出與人腦相似的電腦，可以進行思維、學習、記憶、網路通信等工作。 進入21世紀，電腦更是筆記本化、微型化和專業化，每秒運算速度超過100萬次，不但操作簡易、價格便宜，而且可以代替人們的部分腦力勞動，甚至在某些方面擴展了人的智能。於是，今天的微型電子計算機就被形象地稱做電腦了。世界上第一台個人電腦由IBM於1981年推出。IBM推出以英特爾的x86為硬體架構，以微軟公司的MS-DOS為操作系統的個人電腦，並制定以PC/AT為PC的規格。之後，由英特爾推出的微處理器以及微軟推出的操作系統的發展幾乎等同於個人電腦的發展歷史。Wintel架構全面取代了IBM在個人電腦世界的主導地位。 通常說到「世界公認的第一台電子數字計算機」大多數人都認為是1946年面世的「ENIAC」，它主要是用於計算彈道。是由美國賓夕法尼亞大學莫爾電氣工程學院製造的，它的體積龐大，佔地面積170多平方米，重量約30噸，消耗近150千瓦的電力。顯然，這樣的計算機成本很高，使用不便。這個說法被計算機基礎教科書上普遍採用,事實上在1973年根據美國最高法院的裁定,最早的電子數字計算機,應該是美國愛荷華州立大學的物理系副教授約翰·阿坦那索夫和其研究生助手克利夫·貝瑞(Clifford E. Berry ，1918-1963）於1939年10月製造的"ABC"(Atanasoff- Berry-Computer）。之所以會有這樣的誤會，是因為「ENIAC」的研究小組中的一個叫莫克利的人於1941年剽竊了約翰·阿坦那索夫的研究成果，並在1946年時，申請了專利。由於種種原因直到1973年這個錯誤才被扭轉過來。（具體情況參閱網路----「約翰·阿坦那索夫」詞條，希望大家記住ABC和約翰·阿坦那索夫，希望以後的教科書能夠修改這個錯誤）。後來為了表彰和紀念約翰·阿坦那索夫在計算機領域內作出的偉大貢獻，1990年美國前總統布希授予約翰·阿坦那索夫全美最高科技獎項----「國家科技獎」。
中國電腦 中國的算盤是最早的運算工具。在人類文明發展的歷史上中國曾經在早期計算工具的發明創造方面寫過光輝的一頁。遠在商代，中國就創造了十進制記數方法，領先於世界千餘年。到了周代，發明了當時最先進的計算工具——算籌。這是一種用竹、木或骨製成的顏色不同的小棍。計算每一個數學問題時，通常編出一套歌訣形式的演算法，一邊計算，一邊不斷地重新布棍。中國古代數學家祖沖之，就是用算籌計算出圓周率在3.1415926和3.1415927之間。這一結果比西方早一千年。 珠算盤是中國的又一獨創，也是計算工具發展史上的第一項重大發明。這種輕巧靈活、攜帶方便、與人民生活關系密切的計算工具，最初大約出現於漢朝，到元朝時漸趨成熟。珠算盤不僅對中國經濟的發展起過有益的作用，而且傳到日本、朝鮮、東南亞等地區，經受了歷史的考驗，至今仍在使用。 中國發明創造指南車、水運渾象儀、記里鼓車、提花機等，不僅對自動控制機械的發展有卓越的貢獻，而且對計算工具的演進產生了直接或間接的影響。例如，張衡製作的水運渾象儀，可以自動地與地球運轉同步，後經唐、宋兩代的改進，遂成為世界上最早的天文鍾。 記里鼓車則是世界上最早的自動計數裝置。提花機原理與計算機程序控制的發展有過間接的影響。中國古代用陽、陰兩爻構成八卦，也對計算技術的發展有過直接的影響。萊布尼茲寫過研究八卦的論文，系統地提出了二進制算術運演算法則。他認為，世界上最早的二進製表示法就是中國的八卦。 經過漫長的沉寂，新中國成立後，中國計算技術邁入了新的發展時期，先後建立了研究機構，在高等院校建立了計算技術與裝置專業和計算數學專業，並且著手創建中國計算機製造業。 中國是在1956年研製成功國產計算機的。1958年和1959年中國先後自主研製成功國產小型和大型電子管計算機。60年代中期，中國研製成功一批晶體管計算機，並配製了ALGOL等語言的編譯程序和其他系統軟體。60年代後期，中國開始研究集成電路計算機。70年代，中國已批量生產小型集成電路計算機。80年代以後，中國開始重點研製微型計算機系統並推廣應用；在大型計算機、特別是巨型計算機技術方面也取得了重要進展；建立了計算機服務業，逐步健全了計算機產業結構。 在計算機科學與技術的研究方面，中國在有限元計算方法、數學定理的機器證明、漢字信息處理、計算機系統結構和軟體等方面都有所建樹。在計算機應用方面，中國在科學計算與工程設計領域取得了顯著成就。在有關經營管理和過程式控制制等方面，計算機應用研究和實踐也日益活躍。
The scientific name for electronic computer by early computer, is developed from electric calculator. In 1946, the world appeared the first electronic digital computer "ENIAC", used for calculating trajectory. By the university of Pennsylvania electrician college manufacturing, Moore, the huge volume, but it occupies an area of more than one hundred seventy square meters, weight is about 30 tons, consumption by nearly 100 kilowatts of electricity. Obviously, this computer cost is high, difficult to use. In 1956, transistor electronic computer was born, this is the second generation of computers. Only a few bigger cabinet can will it hold, speed also greatly increased. 1959 appeared in the third generation integrated circuit computer. Early computer by John and von neumann invention (then the computing power of computer now, there are three calculators) is so large, warehouse after between graal development. From 20th century since the 1970s, this is the latest stage of computer development. To 1970, by large scale integrated circuit and vlsi circuits made of "no.1", make the computer clay into the fourth generation. The invention of vlsi, make the electronic computer constantly toward miniaturization, miniaturization, low power consumption, intelligent, systematic direction upgraded. During the 1990s, the computer to "smart" direction development, proce and the brain computer, can undertake similar thinking, learning and memory, network communication, etc. Entering the 21st century, the computer is notebook change, miniaturization and specialization, gigabits per second operation speed over 100 million times, not only operate simple, cheap, and can replace people part mental work, even in some ways expanded the human's intelligence. So, today's microcomputer is what has been aptly called computer. The world's first personal computers launched by IBM in 1981. Introction to Intel's x86 IBM for hardware structure, with Microsoft's ms-dos for the personal computer operating system and formulated to PC/AT for PC specification. Later, launched by Intel microprocessor and Microsoft introced the development of the operating system almost as fast as the development history of personal computers. Wintel architecture comprehensive replaced in the PC world of IBM's dominance. Usually said "the world recognized as the first electronic digital computer" most people think that is available in 1946, "it" ENIAC is mainly used for calculating trajectory. By the university of Pennsylvania is made of electrical engineering college Mohr, its huge volume, covers an area of more than one hundred seventy square meters, weight is about 30 tons, costs nearly 150 kilowatts of electricity. Obviously, this computer cost is high, difficult to use. This statement is widely used Computer basic textbooks in 1973, in fact, according to the United States Supreme Court ruled that the earliest digital electronic computers, should is the Iowa state university physics department associate professor John o SuoFu and its Tampa that graate assistant cliff Berry (Clifford Berry e., 1918-1963) in October 1939 manufacturing "ABC" (Atanasoff - Berry - Computer). Have this misunderstanding, because "ENIAC" one of the research team at Cleveland, called mo 1941, o John plagiarism SuoFu research achievements of the Tampa in 1946, and apply for a patent. Due to various reasons until 1973 this error is turn them around. (particular case refer to - "John o wikipedia entries and SuoFu" Tampa that hope everyone remember ABC and John o SuoFu, hoped later tantra that can modify this error of textbook. Later in order to commend and commemorative John o SuoFu in computer field tantra it within a great contribution in 1990, former U.S. President bush awarded Tampa SuoFu John o across the highest technology awards - "the state" eeffect ".
Chinese computer Chinese abacus is the earliest computing tools. In the history of the development of human civilization in China was once early computing tools invention aspects wrote a glorious page. Shang, China will have created a decimal numeration method, leading in more than 1,000 years. To the zhou dynasty, invented the most advanced computing tools - count chips. This is a kind of bamboo, wood or bone of different colors made of small stick. Computing every math problems, usually make up a set of GeJue forms of algorithm, side calculation, side constantly to cloth stick. Ancient Chinese mathematician zu chong, is calculated by numerical raised in 3.1415927 3.1415926 and between of PI. The results earlier than the west for a thousand years. Abacus plate is another original Chinese, but also in the history of computing tools in the first major inventions. This light and flexible, convenient to carry, and people's living close calculation tool, first emerged when YuHanChao maturity, to the yuan dynasty. Abacus in Chinese economy not only dish played beneficial effects of the development, and spread to Japan, Korea, southeast Asia and other regions, withstand the test of the history, are still in use. Chinese inventions, it was the direction-guiding cart in waterway written instrument, such as car, jacquard machine drums, not only to the development of automatic control machines have outstanding contributions to computing tools, and the evolution proced direct or indirect impact. For example, it was made of zhang heng waterway, can automatically instrument with earth in moving synchronization, by the tang, song after two generations of improvement, thus became the world's first world. The car is written in the world drum, the earliest automatic counting device. Jacquard machine principle and the development of the computer program control have indirect effects. Ancient Chinese Yao with Yang, Yin constitutes a gossip, and two of the development of computing technology have direct influence. Leibnitz wrote research papers, systematically tabloid forward binary arithmetic algorithms. He thinks, the world's first binary representation is China's gossip. After a long silence, after the founding of new China, Chinese computing entered the new developing period, has established a research organization, in universities and colleges to establish computing technology and device professional and computational mathematics, and hands to create China professional computer manufacturing. China is developed successfully in 1956 in home computer. In 1958 and 1959 China has successfully developed independently domestic small and large tube computer. In the mid 60, China has successfully developed computer, and configuration of the transistor such language ALGOL compiler and other system software. In the late 1960's, China began to study computer integrated circuits. In the 1970s, China has batch proction small integrated circuit computer. In the 1980s, China began after key development microcomputer system and popularized; In large computer, especially huge computer technology has also made important progress; Established computer services, and graally improve the computer instry structure. In computer science and technology research, China in finite element calculation method, mathematical theorems machine proof, Chinese information processing, computer system structure and software all aspects contribute. In computer applications, in Chinese scientific computing and engineering design fields have achieved remarkable success. In the related management and process control, computer application research and practice is increasingly active.
❷ 計算機英語短文
What is a Computer?
Computers are machines that can be used for performing calculations automatically. They can perform complex and repetitive proceres quickly, precisely and reliably and can quickly store and retrieve large amounts of data.
The physical components from which a computer is constructed (electronic circuits and input/output devices) are known as "hardware". Most computers have four types of hardware components: input, processor, storage (main memory, auxiliary storage) and output.
Input and output (I/O) devices allow the computer to communicate with the user and the outside world. The CPU (central processing unit) executes programs ("software") which tell the computer what to do.
The two principal characteristics of a computer are: It responds to a specific set of instructions in a well-defined manner. It can execute a prerecorded list of instructions (a program).
Classification of computers
Computers can be generally classified by size and power as follows:
• Personal computer: A small, single-user computer based on a microprocessor. In addition to the microprocessor, a personal computer has a keyboard for entering data, a monitor for displaying information, and a storage device for saving data.
• Workstation : A powerful, single-user computer. A workstation is like a personal computer, but it has a more powerful microprocessor and a higher-quality monitor.
• Minicomputer : A multi-user computer capable of supporting from tens to hundreds of users simultaneously.
• Mainframe : A powerful multi-user computer capable of supporting many hundreds to thousands of users simultaneously.
• Supercomputer : An extremely fast computer that can perform millions of instructions per second.
Generations of Computers
The history of computer development is often referred to in reference to the different generations of computing devices. Each generation of computer is characterized by a major technological development that fundamentally changed the way computers operate. It resulted in smaller, cheaper, and more powerful, efficient and reliable devices.
• First Generation- 1940-1956: Vacuum tubes were used and it relied on machine language to perform operations, and they could only solve one problem at a time.
• Second Generation - 1956-1963: Transistors were used and computers moved from cryptic binary machine language to symbolic, or assembly, languages, which allowed programmers to specify instructions in words.
• Third Generation - 1964-1971: Integrated circuits -Transistors were miniaturized and placed on silicon chips, called semiconctors. Users interacted through keyboards and monitors and interfaced with an operating system.
• Fourth Generation - 1971-Present: Microprocessors -The microprocessor brought the fourth generation of computers, as thousands of integrated circuits were built onto a single silicon chip.
• Fifth Generation - Present and Beyond: Artificial intelligence -Computing devices, based on artificial intelligence, are still in development, though there are some applications, such as voice recognition, that are being used today
IPSO
Most computers have four types of hardware components: input, processor, storage (auxiliary storage) and output. Input and output (I/O) devices allow the computer to communicate with the user and the outside world. The CPU (central processing unit) executes programs ("software") which tell the computer what to do.
IPSO Cycle
The diagram given explains the operations in the computer. First the data enters the computer through the input device, and then processing occurs at the processing unit. The processing unit is the microprocessor chip. Processing unit comprises of the control unit and arithmetic and logical unit and main memory. There are storage devices (auxiliary storage) which store the processed data and data can be retrieved at anytime. The processed data is sent out to the output devices for the user.
Input ----- Processing ------ Storage ----- Output
NEW WORDS AND EXPRESSIONS
automatically adv. 自動地
repetitive adj.各自的
retrieve v. 恢復，補救
physical adj.物理的，自然的
auxiliary adj.輔助的，附加的，副的 n.補助物
main memory 主存
auxiliary memory輔存
execute v.執行，實現
prerecord v.事先錄音
microprocessor n.微處理器
in addition to adv.除…什麼之外
monitor n.顯示器
simultaneously adv.同時地
technological adj.科技的
fundamentally adv.基礎地，根本地
Vacuum tube 電子管
transistor 晶體管
cryptic adj.秘密的，神秘的
binary adj.二進位的
symbolic adj.象徵的，符號的
semiconctor n.半導體
artificial intelligence 人工智慧
❸ 求一篇關於計算機病毒的英文文章
1、打開IE，地址欄輸入www.google.cn。
2、搜索欄後面高級搜索。
3、搜索框輸入ComputerVirus，下面文件格式選擇pdf、doc格式。
4、回車
5、在搜索結果標題中右擊使用迅雷下載，或者目標另存為。
外事問google，內事問網路。
❹ 急求一篇關於計算機用途的英語短文
Internet Virus Spreads 網路病毒的傳播
Experts on cyberspace say the much feared code red computer 1)worm continues to spread through the internet. But so far, the electronic bug that was being considered a global threat to internet 2)traffic seems to have had little 3)impact.
No significant disruptions to traffic on the web have been reported since the code red bug was 4)unleashed early Wednesday. But experts warn the threat may be far from over. Bill Jones, the spokesman of California's Keynote Systems, the company which helps businesses with e-commerce 『I haven』t said anything so far that we call unusual, but we certainly would… But the FBI says the code red worm is still spreading and has the potential to infect internet sites and cause 5)significant disruption to traffic on the world wide web.
"I would expect that the worm has probably not run its course. I would think that because it is a 6)geometric progression, as it infects machines and they infect other machines, you have the opportunity to see a slowdown over time. To have expected something immediately at 0000 UTC Wednesday I think was 7)unrealistic but over the next 24 hours and next few days we could certainly see a slowdown."
Last month, the worm attacked more than 350,000 computer systems running on Microsoft operating systems - including the White House website - and prompted the Pentagon to shut down sites then as well. But it seems that the advice issued by the FBI and cyber instry leaders for internet users to take precautions may have paid off. So far, more than a million people have downloaded a so-called 8)patch from Microsoft's website that prevents computers from being infected.
注釋：
(1) worm [w:m] n.蟲, 蠕蟲
(2) traffic [5trAfIk] n.交通, 通行, 運輸, 貿易, 交通量, 交易, 交往, 通信量
(3) impact [5ImpAkt] n.碰撞, 沖擊, 沖突, 影響vt.撞擊, 壓緊, 對...發生影響
(4) unleash [Qn5li:F] v.釋放
(5) significant [sI^5nIfEkEnt] adj.有意義的, 重大的, 重要的
(6) geometric progression n.[數]等比級數
(7) unrealistic [QnrIE5lIstIk] adj.不切實際的, 不實在的
(8) patch [pAtF] n.修補程序
轉載的~~~~~
還有幾個
Compter Networks
Modem networking applications require a sophisticated approach to carrying data from one machine to another. If you are managing a machine that has many users, each of whom may wish to simultaneously connect to remote hosts on a network, you need a way of allow-in them to share your network connection without interfering with each otherf~3. The approach that a large number of modern networking protocols use is called packet switching. A packet is a small chunk of data that is transferred from one machine to another across the network. The switching occurs as the datagram is carried across each link in the network. A packet-switched network shares a single network link among many users by alternately send-in packets from one user to another across that link.
When talking about TCP/IP networks you will hear the term datagram, which technical-lye has a special meaning but is often used interchangeably with packetE2~. In this section, we will have a look at underlying concepts of the TCP/IP protocols.
TCP/IP traces its origins to a research project funded by the United States Defense Ad-Vance Research Projects Agency (DARPA) in 1969. The ARPANET was an experimental network that was converted into an operational one in 1975 after it had proven to be a success.
In 1983, the new protocol suite TCP/IP was adopted as a standard, and all hosts on the network were required to use it. When ARPANET finally grew into the internet (with ARPANET itself passing out of existence in 1990), the use of TCP/IP had spread to net-works beyond the Intermit itself. Many companies have now built corporate TCP/IP net-works, and the Intermit has grown to a point at which it could almost be considered a main-stream consumer technology. It is difficult to read a newspaper or magazine now without see-in/reference to the Internet; almost everyone can now use it.
Another very important application in TCP/IP networks is NFS, which stands for Net-work File System. It is another form of making the network transparent, because it basically allows you to treat directory hierarchies from other hosts as if they were local file systems and look like any other directories on your hostc3J . For example, all users' home directories can be kept on a central server machine from which all other hosts on the LAN can mount them. The effect is that users can login to any machine and find themselves in the same home directory, Similarly, it is possible to share large amounts of data(such as database, documentation programs)among many hosts by maintaining one of the data on a server and allowing other hosts to access it.
Of course, these are only examples of what you can do with TCP/IP networks. We will now have a closer look at the way TCP/IP works. This information will help you understand how and why you have to configure your machine.
The World Wide Web is a hypertext-based system for finding and accessing Internet resources; it is a set of programs, standards, and protocols governing the way in which multimedia files are created and displayed on the Internet. It can provide access to a variety of Internet resources from the same interface ,including FTP, Gopher and Usenet newsgroups in addition to WWW sites.
作者： 218.200.247.* 2006-2-26 14:31 回復此發言
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2 計算機方面的英語資料，介紹一些計算機的英語短文，有興趣的可以看
The World Wide Web is a distributed, multimedia and hypertext system, and thus a unique medium for communication and for publishing.
Documents for the WWW are written in HTML. The term is used to describe an interlinked system of documents in which a user may jump from one document to another in a nonlinear, associative way. The ability to jump from one document to the next is made possible through the use of hyperlinks. By click the hyperlink, the user is immediately connected to the document specified by the link. Multimedia files on the Internet are called hypermedia documents.
The explosion in use and popularity of Internet in the 1990s is most likely e to the graphics-intensive nature of the World Wide Web. Indivials, companies, and institutions use the Web in many ways. The most widely used tool on the Web is electronic mail, or E-mail, which is used to send written messages between indivials or groups of indivials, often geographically separated by large distances. As a very convenient and inexpensive way to transmit messages, E-mail has dramatically affected scientific, personal, and business communications.
World Wide Web has found application everywhere. E-commerce (business via the Internet) has grown out of businesses that started to advertise their presence via a Web site.
This has broadened into selling procts and services, not only to customers but between businesses themselves. The costs of commercial transactions are negligible, compared with using the traditional distribution and retail network. What is more revolutionary is that the Web can lead to greater political involvement in decision making for ordinary people, via devoting systems.
Web technology has also been extended to handle conferencing and real time communications, to enable it to act like groupware, which facilitates people collaborating over a net-work, especially over an Intranet. The future of the World Wide Web is certain; it will survive and grow. What is uncertain is how it will affect other areas of everyday life.
Wireless Access System ( I )
With its advantages including the short construction period, dispensability with the laying of conits and capability of both data and voice transmission, wireless access can partly or even entirely substitute for wire accessE13 . It is widely used by telecom carriers, which provide voice service largely, and newly emerging Internet service providers (ISPs) and potential local access providers as welled~ . The WA systems used in China have the following six types in terms of frequency bands used.
1. 450/460 MHz WA System: This system finds wide application in rural areas, re-mote suburbs, remote mountainous areas and islands. Some years ago, in order to achieve the objective of making every village accessible to telephone service, the Ministry of Posts and Telecommunications (MPT) extensively used WA systems of this frequency band, pro-mooting the rapid growth of the segments concerned TM . A dozen of manufacturers such ashamed, TCL and Dating proced such systems. However, since these are used mainly in rural areas, their economic efficiency is not as good as is expected. After China Telecom became an independent accounting unit, the development of WA service of this band began to slow down and face fierce competition. This band will not be reallocated; the government encourages telecom carriers to use it for rural communications.
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3 計算機方面的英語資料，介紹一些計算機的英語短文，有興趣的可以看
2. 1800 MHz WA System: This system uses 1800 - 1805 MHz and is based on TDD
molation. Now only the S-CDMA WA systems developed by Dating and deployed in many
places (like Changing) by China Telecom use this band. Owing to the fact that Internet access and mobile terminals are not yet to be introced, the growth of the relevant services impeded. Moreover, this band may possibly be withdrawn for the purpose of 3G generation mobile communications.
3. 1900 MHz WA System: This system is either based on FDD or TDD. The FDD-
based system uses 1880 ~ 1900 MHz/1960 ~ 1980MHz. It adopts CDMA, GSM and PACS.
Since these bands are inconsistent with those designated by the ITU for the use of 3G mobile
communications, in accordance with the regulations of the Radio Regulatory Bureau of theme, they can be used only in Beijing, Tianjin, Shanghai, Guangzhou, Shenzhen, Xiamen,Fuzhou,Cheng and Chongqing by the year 2002 and will be withdrawn and reallocated after that.
The TDD-based WA system uses 1900~1920 MHZ and falls into two types: mobile and fixed. The mobile system, which adopts either PHS or DECT technology, is well known as the radio telephone and mobile phone. The TDD-based fixed WA system uses 1907~1915MHZ and both the CDMA/TDMA molation modes. Now shanghai Bell proces Israel』s Beta-2000 system. This system is used in Ningxia province and part of Hunan province
Wireless Access System(Ⅱ)
4.Spread Spectrum WA System: This system uses 2400~2483.5MHZ/5725~5825MHZ and either direct spread spectrum molation or hopping frequency spread spectrum molation. It can be a normal point-to-point and point-to-multipoint spread spectrum data communications system or a wireless local area network(LAN), providing an emission power no more than 100 mw. The wireless LAN, also known as the wireless network bridge and wireless router , is mainly used for short-distance wireless data access to the Internet. With a directional antenna, the normal wireless spread spectrum data communications system provides a relatively long-distance transmission up to 5~10 kilometers. However, there being quite a lot of illegal systems in use within this frequency band, the electro-magnetic environment Is getting worse and interference occurs frequently. This has affected the further development of spread spectrum WA.
5. 3,5 MHz WA System: This system uses 3400 ~ 3430MHz/3500 - 3530MHz, ma-
inlay for midland and broadband WA. In view of the fact that the extended C-band for satellite communications also uses this band, and taking into account the potential trend of satellite communications, the 3.5 MHz WA is planned to use temporarily the frequencies of the2 x 30 MHz bandwidth. WA of this band is widely used in Europe whereas in the United States it is not open yet. Considering the limited frequency range that has been planned, theta -based WA system cannot use this band for the time being. It is estimated that each city or area can only accommodate a couple of WA operators eventually though many operators have made demand for the band. It is expected that the related frequency allocation and commercial experiments will be carried out in the first half of the year 2001.
6. Broadband WA: As demand for broadband services increases, recent years have seen the strong growth of broadband WA. People generally refer to the local multipoint distribution system (LMDS) as the broadband WA system. Because of its wide bandwidth, its frequencies can only be arranged in a higher band, which allows a short distance.
Generally speaking, because of its good propagation characteristics, the WA system un-deer 1000 MHz is suitable for rural areas, remote suburbs, mountainous areas and islands withal high cost of cable installation, a low teledensity and complex topography. The WA system above 1000 MHz can also serve as a means of installing telephone lines soon. Lacking for re-lasted global unified standards, the WA system is not able to provide roaming. So it is important to encourage the selection of appropriate technologies and systems for different subscribers in different areas and environments. Different WA systems may use different bands flexibly provided that they do not interfere with the operation of existing radio services.
❺ 關於計算機的英語作文
【要求】
在一次主題為「電腦時代」的學校徵文活動中，你計劃以「The Computer」為題寫一篇文章參加評選，你的輔導老師幫助你制訂了一個寫作綱要，如下：
計算機正廣泛被用於各行各業。
在過去的五十年中，計算機得到了迅猛的發展。
計算機最終還是由人來設計和控制。
【範文】
The Computer
The computer is widely used in all phases of society. In instry, business, ecation, medicine, nearly all walks of life, computers have made their appearance, providing great speed and accuracy for our work. Computers have been used in the home, offices, laboratories and research institutions, functioning as the most efficient and versatile instruments for calculating, sorting, filing, recording and distributing. Computers are indispensable to modern civilization. Without computers, our life and our society will undoubtedly suffer a big regression.
During the past five decades the computer has been rapidly advanced. Ever since the computer came into being, it has experienced the development of several generations, which are based respectively on vacuum tube, transistor and integrated circuit. Early computers were of great size, and had no match for the latest electronic computers in speed and accuracy. The Latter is capable of processing the most complicated information and reaching solution to problems in a fraction of time. At present, efforts are being made not only to bring the hardware to perfection, but also to improve the quality of the software.
作文的內容千變萬化，這就要求我們豐富自己的知識，特別是各行業的最新動態。只有這樣，才能自如地處理各種題材和內容。
Computers must be instructed and programmed by people. In spite of the remarkable skill of the computer, men can never become its slave. Computers are not creative. They work according to men's instructions. So the development of computers and their use will depend upon the ingenuity of men. Although there are times when computers seem to operate like a mechanical 「brain」,their achievements are not comparable to what the minds of men are able to do
給分吧