英语科技文章阅读

PrefaceThe ARPANET – the Department of Defense network that is the ancestor of today’s Internet—was built in the late sixties using a proprietary protocol suite. This first protocol proved to have shortcomings for linking with other networks, which led to the development of Transfer Control Protocol/Internet Protocol (TCP/IP). TCP/IP used 32-bit address numbers. These soon proved to be unwieldy for most users, even when expressed in the less daunting formant of four 8-bit decimal numbers, delimited by periods. The obvious solution was a scheme for addressing computers by name. After all, people relate much better to names and find it much easier to remember the computer in the corner as “Frodo,” rather than “.”The First Generation: Hot TablesThe desire to refer to machines by name instead of number led to the first IP address management scheme: the host table. The host table is a file that contains all the IP address in use on a network, along with their names. The host table provides a mapping from a host’s name to its IP address, as well as reverse mapping: Given a host’s IP address, the user can look up its name. For a host table to be most user useful, it must contain the names of all the hosts with which a given host might want to communicate. For the ARPANET, that mean that the host table had to contain the names and IP address of every host on the network. Such a file was maintained by the Network Information Center (NIC), the central organization responsible for managing the ARPANET. The file was called and was similar in format to the/etc/hosts file on UNIX. Network administrators all over the network e-mailed host table changed to the NIC every time they added or deleted a host or changed a host’s IP address. The NIC made the changes to its master host table, which it made available via File Transfer Protocol (FTP). Administrators periodically downloaded the latest version of the host table to stay current.

培养学生英语科技文阅读能力：1．词汇表“八到”记忆法这是中学生使用最多的方法之一，即将生词表和人的器官相结合：眼里看到、心里想到、手里写到、嘴里拿到、耳朵听到、（结合实物还可以）鼻子嗅到、舌头尝到、手指触到。学生在记忆时不要偷懒，一定要边记边比划，把各个器官充分调动起来。这种方法使学生把目标词汇与自己的大脑神经联系，易记忆深刻，印象持久。2．分类记忆法即分析单词的形态，将所要记得单词根据其义、形、音进行分类。例如，按音标的拼读规则记忆单词，按词性变化记忆单词，按同音记忆单词，教师还可教给学生关于英语词根和词缀的知识等；通过词根加前缀或后缀可派生出新的单词，将两个或更多的词放在一起，可合成新的单词。3．联想记忆法苏联著名心理学家巴甫洛夫指出：“记忆要依靠联想，而联想则是新旧正式建立联系的产物。”美国心理学家威廉·詹姆士也说：“记忆的秘诀就是根据我们想记住的各种材料来进行各种各样的联想，而这些联想就成了各种资料的钓钩，万一资料沉没脑海，我们就可以通过联想这样的钓钩将资料钩出来。”充分运用发散思维展开自己的想象力，使所要记忆的英语单词，生动、形象和具体化，使生词与熟词之间建立一种联系，从而达到以旧带新，快速记忆的目的。

这是《科学美国人》杂志上的《PLASTICS GET WIRED》Like many technological advances, the innovations in the field ofconducting polymers began by accident. While attempting tomake an organic polymer called polyacetylene in the early1970s, Hideki Shirakawa of the Tokyo Institute of Technology mistakenlyadded 1,000 times more catalyst than the recipe called for. What he producedwas a lustrous, silvery film that resembled aluminum foil butstretched like Saran Wrap—something that sounds more like a new andimproved way to keep leftovers fresh than a potential breakthrough inmaterials substance appeared so unusual that when Alan G. MacDiarmidspied it, he wondered if it would be a candidate for his goal of making“synthetic metals”—nonmetallic substances that could transmit 1977 Shirakawa joined MacDiarmid and Alan J. Heeger in their laboratoryat the University of Pennsylvania to investigate this form of mixing in some iodine, the group found that the material’sconductivity subsequently jumped by a factor of several , cheap, manufacturable and flexible, conducting polymers inspiredvisions of a future of transparent circuits, artificial muscle and electronicdisplays that conveniently roll up under the arm. Researchers haveauditioned various demonstration devices, including components thatcould be useful for new displays, such as plastic transistors and light-emittingdiodes (LEDs). Although such a future is about as dreamy as it gets,many investigators see broad marketing opportunities possible now—inantistatic coatings, electromagnetic shielding, lights for toys and microwaveovens, among others. Perhaps mundane, such applications are nonethelesspromising enough that universities are collaborating with corporations,and scientists have initiated the pace of technological innovation has been impressivelybrisk, whether the materials will have an effect on commerce remains are unlikely to invest in new equipment if the devices performonly marginally better than existing instruments. Polymer-based batteries,for instance, have a longer shelf life than do conventional ones, but theyhave penetrated the market in only a limited way. Flat-panel displays andLEDs made of organic substances face entrenched competition from existinginorganic liquid crystals and , optimism pervades the field. Because plastic and electrical deviceshave become integral parts of the modern world, researchers are confidentthat at least some profitable uses will emerge. Conducting polymers constitutea radically novel market area, points out Ray H. Baughman of Allied-Signal in Morristown, ., who predicts confidently, “Fortunes aregoing to be made.”Polymers, the constituents of familiar plastic materials and syntheticfibers, are large organic molecules built out of smaller ones linked togetherin a long chain. Generally, they are insulators, because their moleculeshave no free electrons for carrying current. To make these substances conductive,workers exploit a technique familiar to the semiconducting industry:doping, or adding atoms with interesting electronic properties. Theadded atoms either give up some of their spare electrons to the polymerbonds or grab some electrons from the bonds (and thereby contribute positivecharges called holes). In either case, the chain becomes electrically a voltage can then send electrons scampering over thelength of the polymer.《MICROPROCESSORS IN 2020》Unlike many other technologies that fed our imaginationsand then faded away, the computer hastransformed our society. There can be little doubtthat it will continue to do so for many decades to come. Theengine driving this ongoing revolution is the microprocessor,the sliver of silicon that has led to countless inventions, suchas portable computers and fax machines, and has added intelligenceto modern automobiles and wristwatches. Astonishingly,the performance of microprocessors has improved25,000 times over since their invention only 27 years have been asked to describe the microprocessor of predictions in my opinion tend to overstate the worthof radical, new computing technologies. Hence, I boldly predictthat changes will be evolutionary in nature, and not so, if the microprocessor continues to improveat its current rate, I cannot help but suggest that 25 yearsfrom now these chips will empower revolutionary software tocompute wonderful things.《HOW THE SUPERTRANSISTORWORKS》Although it is rarely acknowledged,not one but two distinctelectronic revolutionswere set in motion by the invention ofthe transistor 50 years ago at Bell TelephoneLaboratories. The better knownof the two has as its hallmark the trendtoward miniaturization. This revolutionwas fundamentally transformed in thelate 1950s, when Robert N. Noyce andJack Kilby separately invented the integratedcircuit, in which multiple transistorsare fabricated within a single chipmade up of layers of a semiconductormaterial. Years of this miniaturizationtrend have led to fingernail-size sliversof silicon containing millions of transistors,each measuring a few microns andconsuming perhaps a millionth of a wattin operation. 如果需要更多跟我联系，我有pdf版的资料。

A Boy and His Tree A long time ago, there was a huge apple tree. A little boy loved to come and play around it every day. He climbed to the tree top, ate the apples, took a nap under the shadow… He loved the tree and the tree loved to play with him. Time went by…The little boy had grown up and he no longer played around the tree. One day, the boy came back to the tree and looked sad. “Come and play with me,” the tree asked the boy. “I am no longer a kid, I don’t play around trees anymore.” The boy replied, “I want toys. I need money to buy them.” “Sorry, but I don’t have money…but you can pick all my apples and sell them. So, you will have money.” The boy was so excited. He picked all the apples on the tree and left happily. The boy didn’t come back after he picked the apples. The tree was sad. One day, the boy returned and the tree was so excited. “Come and play with me.” The tree said. “I don’t have time to play. I have to work for my family. We need a house for shelter. Can you help me?” “Sorry, but I don’t have a house. But you can cut off my branches to build your house.” So the boy cut all the branches of the tree and left happily. The tree was glad to see him happy but the boy didn’t appear since then. The tree was again lonely and sad. One hot summer day, the boy returned and the tree was delighted. “Come and play with me!” the tree said. “I am sad and getting old. I want to go sailing to relax myself. Can you give me a boat?” “Use my trunk to build the boat. You can sail and be happy.” So the boy cut the tree trunk to make a boat. He went sailing and did not show up for a long time. Finally, the boy returned after he left for so many years. “Sorry, my boy. But I don’t have anything for you anymore. No more apples for you.” the tree said. “ I don’t have teeth to bite.” The boy replied. “ No more trunk for you to climb on.” “I am too old for that now.” the boy said. “I really want to give you something…the only thing left is my dying roots.” The tree said with tears. “I don’t need much now, just a place to rest. I am tired after all these years.” The boy replied. “Good! Old tree roots are the best place to lean on and rest. Come here, please sit down with me and have a rest.” The boy sat down and the tree was glad and smiled with tears… This is a story of everyone. The tree is our parent. When we were young, we loved to play with Mom and Dad… When we grow up, we leave them, and only come to them when we need something or when we are in trouble. No matter what, parents will always be there and give everything they could to make you happy. You may think that the boy is cruel to the tree but that's how all of us are treating our parents. 很久以前有一棵苹果树。一个小男孩每天都喜欢来到树旁玩耍。他爬到树顶，吃苹果，在树荫里打盹……他爱这棵树，树也爱和他一起玩。 随着时间的流逝，小男孩长大了。他不再到树旁玩耍了。 一天，男孩回到树旁，看起来很悲伤。“来和我玩吧！”树说。 “我不再是小孩了，我不会再到树下玩耍了。”男孩答到，“我想要玩具，我需要钱来买。” “很遗憾，我没有钱……但是你可以采摘我的所有苹果拿去卖。这样你就有钱了。”男孩很兴奋。他摘掉树上所有的苹果，然后高兴地离开了。自从那以后男孩没有回来。树很伤心。 一天，男孩回来了，树非常兴奋。“来和我玩吧。”树说。“我没有时间玩。我得为我的家庭工作。我们需要一个房子来遮风挡雨，你能帮我吗？”很遗憾，我没有房子。但是，你可以砍下我的树枝来建房。“因此，男孩砍下所有的树枝，高高兴兴地离开了。 看到他高兴，树也很高兴。但是，自从那时起男孩没再出现，树有孤独，伤心起来。 突然，在一个夏日，男孩回到树旁，树很高兴。“来和我玩吧！”树说。 “我很伤心，我开始老了。我想去航海放松自己。你能不能给我一条船？” “用我的树干去造一条船，你就能航海了，你会高兴的。”于是，男孩砍倒树干去造船。他航海去了，很长一段时间未露面。 许多年后男孩终于回来了。“很遗憾，我的孩子，我再也没有任何东西可以给你了。没有苹果给你……”树说。“我没有牙齿啃。” 男孩答到。“没有树干供你爬。”“现在我老了，爬不上去了。” 男孩说。“我真的想把一切都给你……我唯一剩下的东西是快要死去的树墩。” 树含着眼泪说。“现在，我不需要什么东西，只需要一个地方来休息。经过了这些年我太累了。”男孩答到。 “太好了！老树墩就是倚着休息的最好地方。过来，和我一起坐下休息吧。” 男孩坐下了，树很高兴，含泪而笑…… 这是一个发生在每一个人身上的故事。那棵树就像我们的父母。我们小的时候，喜欢和爸爸妈妈玩……长大后，便离开他们，只有在我们需要父母亲，或是遇到了困难的时候，才会回去找他们。尽管如此，父母却总是有求必应，为了我们的幸福，无私地奉献自己的一切。你也许觉得那个男孩很残忍，但我们何尝不是这样呢？ 是演讲用的！！！！！！！！！！！