范文一:一篇关于it的英语科技文章 投稿:蔡芙芚


Information technology (IT), as defined by the Information Technology Association of America (ITAA), is "the study, design, development,

implementation, support or management of computer-based information

systems, particularly software applications and computer hardware." IT deals with the use of electronic computers and computer software to convert, store, protect, process, transmit, and securely retrieve information.

Today, the term information has ballooned to encompass many aspects of computing and technology, and the term has become very recognizable. IT professionals perform a variety of duties that range from installing applications to designing complex computer networks and information databases. A few of the duties that IT professionals perform may include data management,

networking, engineering computer hardware, database and software design, as well as the management and administration of entire systems. Information technology is starting to spread farther than the conventional personal computer and network technology, and more into integrations of other

technologies such as the use of cell phones, televisions, automobiles, and more, which is increasing the demand for such jobs.

When computer and communications technologies are combined, the result is information technology, or "info-tech". Information technology is a general term that describes any technology that helps to produce, manipulate, store, communicate, and/or disseminate information

范文二:关于英语作文的文章 投稿:董瓰瓱

Make It Easy

When I was a student, I always feel that writing is not an easy job. so, I understand why our students don't like it.however, Writing won't be difficult any more!It even can be a funny and interesting thing.

When you write about something, you should list the structure: who,when,where, why,how and so. It means you just think about: Who is the story about? When did it happen? Where did it happen? Why did it happen? And how did it happen? At last, you should show the ending.

And then, we make writing step by step. Stage one:describe characters,by using some adjectives.Stage two:set the scene, just use your imagination. Stage three: told the readers what happened.

That's all! Thanks.

范文三:科技英语文章 投稿:孟懰懱


Arctic Melt

Earth's North and South Poles are famous for being cold and icy. Last year, however, the amount of ice in the Arctic Ocean fell to a record low1.

Normally, ice builds in Arctic waters around the North Pole each winter and shrinks during the summer. But for many years, the amount of ice left by the end of summer has been declining.

Since 1979, each decade has seen an 11.4 percent drop in end-of-summer ice cover2. Between 1981 and 2000, ice in the Arctic lost 22 percent of its thickness -- becoming 1.13 meters thinner.

Last summer, Arctic sea ice reached its skimpiest levels yet. By the end of summer 2007, the ice had shrunk to cover just 4.2 million square kilometers. That's 38 percent less area than the average cover at that time of year. Andit's a very large 23 percent below the previous record low, which was set just 2 years ago. This continuing trend has scientists concerned There may be several reasons for the ice melt, says Jinlun Zhang, an oceanographer at the University of Washington3 in Seattle. Unusually strong winds blew through the Arctic last summer. The winds pushed much of the ice out of the central Arctic, leaving a large area of thin ice and open water4.

Scientists also suspect that fewer clouds cover the Arctic now than in the past. Clearer skies allow more sunlight to reach the ocean. The extra heat warms both the water and the atmosphere. In parts of the Arctic Ocean last year, surface temperatures were 3.5℃Celsius warmer than average and 1.5℃ warmer than the previous record high5.

With both air and water getting warmer, the ice is melting from both above and below. In some parts of the Beaufort Sea6, north of Alaska and western Canada, ice that measured

3.3m thick at the beginning of the summer measured just 50 centimeters by season's end. The new measurements suggest that melting is far more severe than scientists have seen by just looking at ice cover from above, says Donald K. Perovich, a geophysicist at the U. S. Army Cold Regions Research and Engineering Laboratory in Hanover, N.H.7

Some scientists fear that the Arctic is stuck in a warming trend from which it may never recover.


1. Which of the following is closest in meaning to the word

A) Construct. B) Extend. C) Create. D) Expand.

2. What is the ice cover in the Arctic by the end of 2007 summer?

A) 4.2 million square kilometers. B) 11.4 million square kilometers. C) 1.13 million square kilometers. D) 38 million square kilometers.

3. What are the reasons for the ice melt according to the scientists?

A) Strong winds and clear skies. B) Long summer and short winter.

C) Open water and thin ice. D) Light clouds and light winds.

4. Why is the ice melting from both above and below?

A) Because extra heat warms the air.

B) Because extra heat warms the water.

C) Because the temperature above the water is higher.

D) Both A and B.

5. What can be a possible title for the passage?

A) What are scientists looking for in the Arctic Ocean?

B) What are scientists doing in the Arctic Ocean?

C) Why are scientists worrying about the Arctic Ocean?

D) Why are scientists interested in the Arctic Ocean?

Experts Call for Local and Regional Control of Sites for Radioactive Waste

The withdrawal of Nevada's Yucca Mountain as a potential nuclear waste repository1 has reopened the debate over how and where to dispose of spent nuclear fuel and high-level nuclear waste. In an article in the July 10 issue of Science, University of Michigan2 geologist Rodney Ewing and Princeton University3 nuclear physicist Frank von Hippel argue that, although federal agencies should set standards and issue licenses for the approval of nuclear facilities, local communities and states should have the final approval on the siting of these facilities. The authors propose the development of multiple sites that would service the regions where nuclear reactors are located.

Ewing and yon Hippel also analyze the reasons why Yucca Mountain, selected by Congress4 in 1987 as the only site to be investigated for long-term nuclear waste disposal, finally was shelved5 after more than three decades of often controversial debate. The reasons include the site's geological problems, management problems, important changes in the Environmental Protection Agency's standard, unreliable funding and the failure to involve local communities in the decision-making process.

Going forward, efforts should be directed at locating storage facilities in the nation's northeastern, southeastern, midwestern and western regions, and states within a given region should be responsible for developing solutions that suit their particular circumstances. Transportation of nuclear waste over long distances, which was a concern with the Yucca Mountain site, would be less of a problem because temporary storage or geological disposal sites could be located closer to reactors.


radioactive adj.放射性的 shelve v.搁置 repository n.储藏地,储藏室 controversial adj.有争议的

geologist n.地质学家 reactor n.反应堆,反应器 geological adj.地质的


1. The withdrawal of Nevada's Yucca Mountain as a potential nuclear waste repository: Nevada's Yucca Mountain:美国境内的内华达州尤卡山。nuclear waste repository:核废物处理库。美国能源部部长朱棣文 2009 年 3 月 5 日表示,拟在内华 达州尤卡山建设的核废物最终处理库将不再是美国储存高放废物的一个选项。

2. University of Michigan:美国密歇根大学,建于 1817 年。

3. Princeton University:美国普林斯顿大学,建于 1746 年。

4. Congress: 美国国会,美国最高立法机关,由参议院(Senate)和众议院(House of Representatives)组成。

5. „was shelved:......被束之高阁。

6. spent nuclear fuel:也叫做 used nuclear fuel,一般译为“乏核燃料”。

7. high-level nuclear waste:高(强度)放(射性)核废物。

8. geological repositories in a variety of rock types:各种不同岩层中的地质处置 库。geological repositories 指的是地表以下 300~1500 米的稳定的地质体中建造的 用于最终处置高放废物和乏核燃料的工程设施。处置库是一个多重屏障系统,工程屏障 由废物体、废物罐、外包装和缓冲回填材料组成,而天然屏障则是能有效阻滞放射性核 素迁移的地质体,包括花岗岩、粘土岩、凝灰岩和岩盐等。许多专家认为地质处置是安 全的,技术上是可行的,对环境是无害的。 练习:

1. Which of the following words can best substitute the word

A Retirement. B Canceling. C Replaced. D Disposal.

2. According to Rodney Ewing and Frand von Hippel, where to locate nuclear facilities

A should be approved by the federal government.

B should be approved by local people and states. C should be approved by Congress.

D is not an important issue.

3. What is NOT true about the 1987 decision by Congress concerning siting of nuclear waste disposal?

A Yucca Mountain was selected as the only site for a nuclear waste repository.

B The selection of Yucca Mountain for nuclear waste disposal caused much controversy.

C The decision by Congress was put aside due to a number of problems. D The decision by Congress was accepted by local communities.

4. What does the author of the essay in the fourth paragraph want to say?

A Efforts should be made to solve the problems of transportation of nuclear waste over long distance.

B Efforts should be made to develop as many nuclear disposal sites in the US as possible.

C Efforts should be made to develop nuclear disposal sites to suit the circumstances of the region.

D Efforts should be made to build up temporary nuclear disposal sites as possible.

5. What is meant by

A Waste disposal sites are located close to reactors and in places suitable for the regional circumstances.

B Geological repositories are located in a variety of rock types.

C Spent nuclear fuel and high –level nuclear waste is moved to developing countries.

D Waste disposal sites are located far away from reactors.

范文四:英语科技文章 投稿:朱鈥鈦

弹指之间 At Your Fingertips

触控荧幕的应用非常广泛,例如游客导览系 We use touch screens everywhere: tourist 统、自动柜员机、销售点终端机、工业控制系统等。kiosks, automatic teller machines, point-of-sale 在2000年,六家专门厂商加上几家大公司的触控terminals, industrial controls. Half a dozen 产品部门,总产值高达八亿美元。由于这种介面使vendors, plus in-house departments at major 用方便、经久耐用,而且花费不高,因此市场还在manufacturers, produced $800 million worth in 成长之中。 2000. The market is growing because the 触控荧幕可依其侦测触控点的物理原理,分为interfaces are easy-to-use, durable and


生电压;电容式荧幕,手指会吸取微小的电流(常 Touch screens employ one of three physics 用于笔记型电脑的触控板)。至于第三种波动式荧principles for detecting the point of touch. Pressing 幕,则是用声波或红外线覆盖整个表面,而手指或a “resistive” design with a finger or other stylus 触头会阻断这些驻波图样。 raises a voltage. In “capacitive” models, a finger 电阻式荧幕是历史最久、用途最广,也是价格draws a minute current (this method is often used 最低的一种,而且任何触头(无论手指或笔尖)都for cursor pads on notebook computers). In other 可以使用。电容式荧幕必须使用手指,或是接有地designs, a finger or stylus interrupts a standing 线的触头,以便传导电流。波动式荧幕则是最新且pattern of acoustic waves or infrared lights that 最昂贵的类型。表面声波荧幕必须用手指或软式触blanket the surface.

头(例如铅笔上的橡皮擦)轻触,以吸收表面能量; Resistive screens are the oldest, most widely 红外线触控荧幕则可使用任何触头。在实际应用used and least expensive, and they work with any 上,可以同时选用好几种技术,不过基于各技术的stylus (finger, pen). Capacitive screens must be 优缺点,通常导致以下的组合:工业控制系统和掌touched by a finger or an electrically grounded 上型电脑Palm Pilot使用电阻式,自动贩卖机使用stylus to conduct current. Wave screens are the 电容式,自动柜员机及室内资讯站使用波动式。但newest and most expensive. Surface acoustic 是大多数人并不清楚,自己所使用的荧幕是什么类wave screens must be touched by a finger or a 型。 soft stylus such as a pencil eraser to absorb

沈辉斌任职于美国最大的触控荧幕制造商──energy; infrared screens work with any stylus. The 位于加州夫利蒙市的“易触控系统公司”,他提供了different technologies may be used in the same 以下的辨别诀窍。你可用指甲(而不是皮肤)轻压applications, although pros and cons lead to 荧幕,假如荧幕有反应,就可能是电阻式或红外线prevalent combinations: resistive screens for 式荧幕。果真如此,再同时用两根手指分别轻压荧industrial controls and Palm Pilots; capacitive

幕上两点。假如游标移到其中一根手指下方,这装screens for slot machines; wave screens for ATMs 置使用的就是红外线(软体只记录第一个接触点);and indoor kiosks.

假如游标移到两根手指之间,荧幕就是电阻式(两 Most people are unaware of the type of

个接触点皆有影响力)。假如这个装置对指甲毫无screen they are using. But tricks can help you tell, 反应,你的下一步还是用两根手指分别轻压荧幕上according to Frank Shen of Elo TouchSystems in 两点。这时候,如果游标移到其中一根手指下方,Fremont, Calif., the largest U.S. maker. Push the

那么这荧幕使用的原理是声波;假如游标移到两根screen lightly with your fingernail (not your skin). If 手指中间,它就是电容式触控荧幕。

it responds, it could be resistive or infrared. In this case, place two separated fingers against the

screen at the same time. If the cursor moves

beneath one finger, the unit is infrared (software

registers the first touch); if the cursor moves

between the fingers, it is resistive (the points are

averaged). If the unit does not respond to your

fingernail, again place two separated fingers

against it. If the cursor moves beneath one finger,

the unit is acoustic wave; if the cursor moves

between the fingers, it is capacitive.

Science Shows Lying Is Hard Work

A convicted sex offender, released on parole, submits to

a polygraph test.

machine barely shift from their rhythmic movements.

You can guess, of course, whether the man was

answering truthfully - but today's polygraphs cannot. All

they record are pulse, respiration, skin temperature, and

other signs that may suggest whether someone seems

nervous when asked a damning question.

Machines can be fooled, but it may not always be that


blood flow,

professor of psychiatry at the University of Pennsylvania

Medical School.

Langleben and his colleagues have been experimenting

with computerized brain scans - functional magnetic

resonance imaging. This giant machine can show the

amount of blood flow to different sections of the brain in

precise detail.

They wanted to see what changes could be measured

inside the brain when people are deceitful. They asked

people to lie inside the scanner and lie through their 他们想知道能否测定出说谎者的脑内变化。他们要求受试者在此机扫描时说谎。用电脑将许多受试者说谎的测试结果加权和Langleben博士和他的同事已经试验了一种计算机脑扫描即功能性磁共振成像。这种巨大的机器能精确显示出流到脑不同部位的血流量。 宾夕法尼亚大学医学院的精神病学副教授Daniel Langleben博士说:“我想控制脑血流是非常难的。” 说真话 科学表明 说谎不易 一位因性攻击被定罪的犯人在假释时做测谎试验, 检查人员问:“你曾经说过谎吗?”这个男子说:“没有”。这时,测谎仪的针头仅仅有规则地运动着 当然,你可能猜想这家伙在说假话,但今天所用的测谎仪却不能。它们所能记录的脉搏、呼吸、皮肤温度和其它信号,只能提示某人在回答一个非常不利的问题时似乎有些紧张。 机器可能被愚弄,但它不会总是那么傻。

teeth .when answers from many test subjects were 平均,结果清楚表明当人们说谎时比说真话combined and averaged by a computer, they clearly 时要多用某部份大脑。

showed that when people lie, they use more sections of

the brain than when they tell the truth.

something is the truth,

may naturally be truth tellers. The brain works harder to


Langleben was never out to make a better lie detector,

but his research, along with others', could someday lead

to one.



编辑:John C. H. Chen














问题。国际保护阿尔卑斯山组织(International Commission for Protection of the Alps,

CIPRA)的Michel Revaz就表示,制造人造雪要消耗水及能量。而这些人造雪所溶化的水也




Skiers take to man-made slopes

As demand grows for manufactured snow, so does environmental impact.

by Helen Pearson 需抑制某些东西,是否这东西就是真实,” 他说。“换言之,人的本性是要说真话的,说谎对大脑并非易事。” Langleben并未打算制造出一台更好的测谎仪,但他的研究和其它研究成果最终会催生这种机器。 美联社

The 2006 winter Olympics is highlighting winter-sport enthusiasts' growing reliance on man-made snow, and the toll that this addiction could take on the environment.

All competitive ski and snowboarding events now take place largely on man-made snow. Unlike its natural counterpart, the machine-made white stuff can be carefully tweaked to make a more durable and consistent surface: one perfect for record-breaking attempts. The Olympic ski resorts outside Turin, Italy, have extensive snow-making facilities and several new reservoirs were built for the games to supply water for snowmakers. In recent weeks they have been piling on man-made snow, as the natural stuff has proven rather thin on the ground in the Turin area this season.

Snow-making equipment is viewed as essential in most ski areas to guarantee coverage throughout the season. Nowadays,

snow-making technology company York Snow in Victor, New York, whose systems were used in the 2002 winter Olympics in Salt Lake City, Utah, and previous games.

Nature's copycats

「It's not clever to build a new piste every four years.」

Michel Revaz The sno

w International Commission for Protection of the Alps (CIPRA), Schaan, Liechtenstein. 'can

nons' or 'guns' that manufacture snow mimic the natural formation of snowflakes. Snow machines typically force pressurized water through a nozzle, breaking it into a mist of tiny droplets, and then use compressed air or fans to blast them into the air. As the droplets cool, the molecules align and crystallize into ice particles.

The art to snow-making is adjusting the water and air to ensure that the water drops are small enough and sent far enough that they will freeze before they hit the ground. If the air temperature is quite high, for example, dropping the water content and upping the air would create smaller particles that are more likely to freeze.

Snow-making machines also frequently incorporate nucleating agents in the water: small quantities of materials such as bacterial protein, on to which the water molecules attach and freeze. By triggering freezing, these agents raise the temperature at which snow can be made.

Many resorts now use sophisticated computer systems that automatically adjust the air and water output from snow machines based on air temperature, humidity and wind, says Brown.

Skiing on ice

For race courses, experts adjust man-made snow to create a tough, fast and icy course rather than a powdery one. A ski course is also heavily groomed and often intentionally flooded to create patches of ice; these factors generally determine the speed of a race. There are other reasons for snow manufacturing to be in demand, beyond the benefits of having a snow whose properties can be ordered up. Some predict that the need for snow will rocket with the warming effects of climate change, which are already pushing snow lines up the Alps.

But this comes with environmental costs, says Michel Revaz, of the International Commission for Protection of the Alps (CIPRA), a conservation group in Schaan,

Liechtenstein. Making snow chews up energy and water, and can rob rivers and creeks in the surrounding ecosystems.

One way to conserve the mountain environment, Revaz says, would be to reuse winter sports competition facilities rather than building new ones.

Telepathy--mind to mind contact

Telepathy is the ability to communicate

without the use of the five senses(sight, 心灵感应:心与心的交流 心灵感应是不用五官感觉(视觉、听觉、触觉、嗅觉、味觉)来进行交hearing, touch, smell, taste).It is an instinct, 流的一种能力。它是我们许多人体内and although quite dormant in many of us, we 潜在的一种本能。在紧急关头或是需are often capable of tapping into our latent 要的时候, 我们常常都能激发出这种abilities in times of emergency or need. 潜能。

Where this instinct lies is uncertain.Some say 这种本能存在于哪里还无法确定。that it is located in the huge area of our brains 有人说它存在于我们的大脑中完全未that are wholly unused, whereas others argue 使用过的大片区域;然而也有人说, 在that instinct existed before the brain evolved 大脑进化前, 它就已经存在, 因此它and must therefore lie else-where in the body. 必定存在于身体的其他部位。

When we intuitively know that something is 当我们凭直觉知道某些事情正在发happening, or about to happen, our instinct has 生或即将发生时, 我们的本能就已发kicked in.We are drawing upon resources

within the unconscious mind.When the

resources of two unconscious minds link

together into the same frequency, we call it 生作用了。我们正在利用无意识意念中的资源。当两个人的无意识意念资源相互联系而达到同步时, 我们称之为


Telepathy can be either projective or

perceptive, we either send or receive.If you

know who is calling before you answer the

ringing phone, you are probably a good 心灵感应可以投射或感知, 也就是说我们或者发送或者接收它。如果你在接听一个打来的电话前, 就知道对方是谁, 那么你可能就是一个好的接receiver.If you think of a person, and they call 收者。如果你正在想着某人, 然后他就you, you are most likely better at sending.

You can easily put your abilities to the

test.Think of somebody and will them to 你可以轻易地测试你的这项能力, 给你打电话了, 那么你可能更擅长于发送感应。 contact you.Be patient, the other person may 用心想着某人, 用自己的意志使他们not be a good receiver, but they should contact 和你联络, 因为别人未必是个好的接you much earlier than would normally be

expected.Or whenever the phone rings, try 收者, 所以你要耐心地等待。但他们应该会比平时正常情况下你所预期的时


Telepathic Dreams Dreams often contain

telepathic messages.Two people may both

dream of the other, and find that their dreams

had a distinct connection.These people are

probably mutually linking to the unconscious

mind.A projection of the mind--a form of

astral projection?

Telepathy&Relationships The more people 梦境中的心灵感应 梦常常包含着心灵感应的信息。两个人可能互相梦见对方, 而且发现他们的梦有着清晰的联系。这些人的无意识意念很可能是相互联系的。这是不是一种意念的投射--一种存在于有形世界之上的超感觉的投射方式呢? 人与人的关系与心灵感应 人们在spend time together, the more likely they are to 一起相处的时间越长, 他们的心灵相be able to link up to the others mind, especially 互间就越有可能产生共鸣, 尤其当他when separated.There are two reasons for

this.One is that they understand the others, 们分开的时候。对此有两种解释, 一是通过一段时间的相处, 人们彼此间获mind through time spent together;the other is 得了心灵的相互理解。二是人们通常that there is usually a strong desire to

communicate. 存在一种相互联系的强烈愿望。

A mother will often sense that her child is in

danger.This is due to the child desperately 一位母亲常常能感知她的孩子身处险境。这是因为她的孩子非常想得到wanting his/her mother, knowing that this is the 母亲的帮助, 他们知道母亲是随时都person who would always want to be there for 愿意来到自己身边, 给予帮助的人, them, and the mothers deep desire to protect

her child from harm. 而母亲也有保护她的孩子免受伤害的强烈愿望。英语文摘 By Sharon

Jacobsen (吴华 摘译自Girl Posse)

New Fingerprint Technology Developed

Los Alamos

National Laboratory

scientists are using

a new technique to

see fingerprints on

surfaces that

typically make them


The method uses a 参与该科研项目的科学家克里斯托弗·沃尔利说,该方法使用了一种“微X射线束荧光技术”,可以探测到指纹携带的化学成分,却不会改变指纹的保存状态。







fingerprint patterns with regular light and they have

to treat those with powder, which alters them,

Worley said.

treat it at all. We can determine the elements in a

fingerprint and get a pattern at the same time.

The technology focuses a tight beam of X-rays on

surfaces with fingerprints and creates a computer

picture out of those scans.

这项技术将一束密集的X光对准留有指纹的物体表面,并根据扫描结果创建出计算机图像。 这套设备造价17.5万美元。 该实验室的另一位科学家瓦希德·马吉德表示,对那些大实验室

来说,这是获取用其他方法看不分,同时获取指纹图案。” New Fingerprint Technology technology called Developed mini-X-ray 美国洛斯阿拉莫斯国家实验室的科学家们采用了一种新技术,可以观察到原本很难在物体表面上看见的指纹。 fluorescence to detect chemical elements in fingerprints without altering them, said Christopher Worley, a scientist on the project.

The equipment costs about $175,000.

For big labs, the method could be a great way to

bring out prints that can't be seen any other way,

said Vahid Majidi, another lab scientist.

If you have prints on a dark surface, for example,

they really don't develop well using normal

techniques. If you have prints from an adolescent or

child, the chemicals in the fingertips are different

and don't stick around long enough for traditional


The new method might also be able to tell if the

person that left them handled certain types of

bomb-making materials, said George Havrilla,

another lab scientist.

Havrilla said.

looking at the finger's natural oils and organic

residues we're looking at elemental features left


The technology for scanning the prints is widely

available. What's new is the method the lab has

created to see them which includes computer

software and ways of manipulating the machinery,

Worley said.

But the technique isn't for everyone.


it's just not practical. But the goal of our work was to

demonstrate that it was feasible to see these 到的印迹的最好方法。 马吉德说:“这项技术填补了一项空缺。如果没有这项技术,某些印迹就会变得毫无意义。比如说,如果是深色表面上的指纹,普通技术确实无法精确地探测到它们;如果是青少年或小孩的指纹,他们的指尖留下的化学成分(和成人)是不同的,而且这些指纹附着在物体表面的时间并不久,因此不适宜使用传统的分析方法。” 该实验室的另一位科学家乔治·豪夫里洛表示,这种新技术也许还能检测出指纹所有者是否触摸过某些类型的炸弹制造材料。 豪夫里洛说:“这是清晰显示指纹的一种新途径。我们查找印迹时不再只观察手指分泌的油脂和残留有机物,而是专注于其背后隐藏的特殊化学成分。” 沃尔利指出,扫描印迹的技术目前已被广泛采用。该实验室发明的这种新型指纹探测法的创新之处在于它包含了计算机软件技术和机器操作方法。 但是这一技术也并非众人皆宜。 豪夫里洛笑着说:“我们已经收到了一些负面评论。一位批评者对我们说它压根不实用。但我们工作的目标是证明这种技术是切实可行的。”


fluorescence: the emission of electromagnetic radiation, especially of visible light, stimulated in a substance by the absorption of incident radiation and persisting only as long as the stimulating radiation is continued(荧光,尤指可见光等电磁辐射的散光) niche: a special area of demand for a product or service(适当的位置,产品或服务所需的特殊领域)

stick around: 逗留

residue: the remainder of something after removal of parts or a part(残留物) things.

Switches and Fuses开关和保险丝

An electric switch is often on a wall near the door of a room. Two wires lead to the lamp in the room. The switch is fixed in one of them. The switch can cause a break in this wire, and then the light goes. The switch can also join the two parts of the wire again, then we get a light.

Switch can control many different things. Small switches control lamps and radio sets because these do not take a large current, larger switches control electric fires. Other switches can control electric motors.

Good switches move quickly. They have to stop the current suddenly. If they move slowly, an electric spark appears. It jumps across the space between the two ends of the wire. This is unsafe and it heats the switch. Very big switches are sometimes placed in oil, Sparks do not easily jump through oil, and so the oil makes the switch safer.

A large current makes a wire hot. If the wire is very thin, even a small current makes it hot. This happens in an electric lamp.

The electric wires in a house are covered with some kind of insulation. No current can flow through the insulation, so the current can never flow straight from one wire to the other, but the insulation on old wires is often broken, then the copper of the two wires can touch. A large current may flow, and if this happens, the wires will get very hot. Then the house may catch fire.

Fuses can stop this trouble. A fuse is only a thin wire which is easily melted. It is fixed in a fuse-holder(保险盒). The fuse-holder is made of some material which cannot burn. A large current makes the fuse hot and then it melts away. We say that the fuse

When a fuse blows, something is wrong. We must find the fault first. Perhaps two wires are touching. We must cover them with new insulation of some kind. Then we must find

the blown fuse and repair it. We put a new piece of fuse- wire in the holder. (Sometimes we can find the right fuse- holder because it is rather warm, but the others are cold.) If we do not repair the fault first, the new fuse will blow immediately.

Some men get angry when a fuse blow. So they put a thick copper wire in the fuse-holder! Of course this does not easily melt; if the current rises suddenly, nothing stops it. The thick wire easily carries it. Then the wires of the house may get very hot and the house may catch fire. Some of the people in it may not be able to escape. They may lose their lives. So it is always best to use proper fuse-wire. This will keep everyone and everything in the house safe.

The First Airplane Flight

American aviators Orville Wright and Wilbur Wright of Dayton, Ohio, are considered the fathers of the first successful piloted heavier-than-air flying machine. Through the

disciplines of sound scientific research and engineering, the Wright brothers put together the combination of critical characteristics that other designs of the day lacked—a relatively lightweight(重量轻的) (337 kg/750 lb), powerful engine; a reliable transmission and efficient propellers; an effective system for controlling the aircraft; and a wing and structure that were both strong and lightweight.

At Kitty Hawk, North Carolina, on December 17, 1903, Orville Wright made the first successful flight of a piloted, heavier-than-air,

self-propelled craft, called the Flyer. That first flight traveled a distance of about 37 m (120 ft). The distance was less than the wingspan of many modern airliners, but it represented the beginning of a new age in technology and human achievement. Their fourth and final flight of the day lasted 59 seconds and covered only 260 m (852 ft). The third Flyer, which the Wrights constructed in 1905, was the world’s first fully practical airplane. It could bank(倾斜转弯), turn, circle, make figure eights, and remain in the air for as long as the fuel lasted, up to half an hour on occasion.

范文五:科技英语文章 投稿:邓竂竃


An exoplanet, called WASP-12b which is about 1,200 light years from Earth and 1.4 times the mass of Jupiter has been considered suitable for life existence, although a little hot. And its sibling planets could even be made of diamonds, according to new research findings.


A team led by researcher Nikku Madhusudhan of Princeton University and scientist Joe Harrington of the University of Central Florida monitor WASP-12b during one of its orbits, particularly in the instants before it passed behind its home star. In those brief moments, the light from the star would flow through the planet's atmosphere, allowing astronomers to study the wavelengths produced and infer the atmosphere's chemical composition.

由美国普林斯顿大学的研究员尼库 马杜苏丹和佛罗里达中部大学的科学家乔 哈林顿领导的一个研究小组检测WASP-12b的一次绕轨运行情况,特别是在它从其母恒星后面经过的那一刻。在这一刹那,恒星发出的光会穿透行星的大气,天文学家得以研究产生的波长,并推断行星大气的化学成分。

They found some exoplanets, WASP-12b included, have carbon-rich

chemistry: Some have atmospheres with a carbon-to-oxygen ratio of about 0.5. As for WASP-12b, however, there was more than twice the concentration of carbon as usual and almost 100 times more methane than expected.


That has big implications for extraterrestrial biology, since life is based on carbon, and methane - which is made up of carbon and hydrogen - is a

byproduct of metabolism. The planet's carbon-heavy atmosphere could retain heat and light, providing energy for life to get started and thrive. That life would have to survive on comparatively little oxygen and water, and would have to be very tolerant of methane.


As for some of the planets formed along with WASP-12b, they could easily be smaller, with rocky formations made not of silica, like Earth's, but of graphite or - given enough time and enough pressure - precious diamonds.





范文六:关于春联的英语文章 投稿:江鎏鎐

Chinese Chun Lian:Spring Couplets

chun lian is a special type of duilian, or couplet. it is used only during the chinese new year as part of its celebration. while duilian is permanent, chunlian is a temporary decoration to be placed on the entrance of the house, somewhat akin to halloween and christmas decorations.

duilian comprises of a couplet written on vertical strips of red paper in the best calligraphic style one can muster.

the first (called upper) line is posted on the right side of the front door.

the second (called lower) line is posted on the left side of the front door.

in addition, a third horizontal piece may be posted across and on top the door.

look at this picture or this for a general idea.

look at this painting depicting the scene of writing couplets

typically, the chun lian writes an happy, hopeful, uplifting message about a better new year to come, like this one:

word-for-word translation of above:

top (horizontal across)   : whole   earth  returns  spring

left (vertical) line    : winter gone mountain clear water sparkles

right (vertical) line: spring comes   bird    sings flower fragrant

note that word for word, the upper and lower lines are antithetical, yet the meanings are complementary and content of the message is hopeful and uplifting. the words in the horizontal are written from left to right.

范文七:关于运动的英语文章 投稿:刘蟳蟴

A:May I sit here? B:Yes, please. So you're also a freshman in the Department of traditional Chinese medicine ?

A:Certainly. Today only traditional Chinese medicine students are here. I'm A, from class1.

B:Nice to meet you. B, from class 1 too . Nice to meet you, too.

A:Oh ,we are classmates. So good! A:How have you found your university life during this past month?

B:Everything's new and exciting. University life is more colorful than I expected. B:What do you think? A:The same as you.

A:Mmm, can I ask you a question?


A:B, what kind of exercises do you like to do? Becasue you look good, and your body are very healthy.

B:Well, I love to ride bike .And I go cycling every day.

A:What do you like about them?

B:They're free of charge anyway. Well, it makes me feel stronger, but the most important thing is that it makes me feel good.

A:What else do you do?

B:Playing badminton ,playing table tennis , jogging .

A:Wow!!That sounds great. How often do you go jogging?

B:I try to do at least a little every day. The key to do exercise is to do it regularly. A:What are the best exercises for my health?

B:I think it's impossible to name one exercise that's good for everyone.

B:What about yoga?

A:Oh, yeah, I almost forgot. Yoga now is the most popular exercise in the States. Lots of people are doing that, especially those movie stars. They think it's a good way of losing weight and it can calm you down, make you think of nothing, just concentrate That sounds like Chinese breath exercise.

B:What is that?

A:It's called Qigong. It's just like yoga. You know that stuff, but in a different way. B:Well, A, what's your favorite sport?

A: Sleeping I guess.

B: Uhh. I think sleeping as well as a good “sport” .

A: HAHA. You have a fund of good humor .

A: It’s time for class !

B: Yes . Let’s listen to the course carefully. And I am glad to have the opportunity to speak with you .

A: Me too .

范文八:关于名字的英语文章 投稿:曹诵诶

The importance of a name

Social scientists say that what you're called can affect your life . Throughout history, names have not merely identified people but also described them. For better or worse , sometimes qualities may be suggested by your name and conveyed to other people before they even meet you. A name, as the symbol that represents one’s identity, is very important in our life from we are born.

In China, parents attach great importance to names because their children’s names usually contain the characteristics that they want their children to possess. For example, many Chinese boys have the character ‘Yong’, which means brave. Furthermore, an eye-catching name can also create a good first impression and thus benefit one’s career. This is why many stars choose to change their names once they become famous.

Meaning of Chinese names

1 See your fate from name

Chinese people always attach great importance to the choice of names. In the Chinese earliest dictionary it was explained as follows: name contained the invisible fate and the visible and meaning characters. Fate was something not easy to definite. It coincided with 'the hidden material,' metal, wood, water, fire, and earth .The five elements decided by the birth date according to the astrological principles. Nowadays, we

think it superstition , but there are still some rules of thumb tend to be followed by parents, like balance between the baby's birth date and the five elements in its life. Take my name for example, after I’m born, my mother asked a fortune-teller about my fate and my name, it’s said I’m lack of metal, so you can see there is a 金 in my name.

2 See the develop of country from names.

The May Fourth Movement in 1919 make drastic changes in Chinese culture. So did it influence names. It contended all sorts of characters could be used to form a person's name. Then after the founding of New China, name began to take on a political touch, such as 'Ai Guo' which means 'love the country' and so on. Another obvious change in Chinese name is that many people now use only two characters. A study shows that, before 1966, about 90 percent of chinese names had three characters. But a recent survey tells us that about half of today's younger people have two character names.

Meaning of English names

English first name has many origins.

1 Christianity. It’s one of the most influential sources because most English-speaking countries are Christian countries. Traditionally, a child is given a Christian name by its godfather and godmother at baptism. Parents often give their children names after the people in the Bible. Such

biblical names as Adam, Abraham, Daniel, and Peter are most commonly used first name.

2 Mythology. For example, in several thousands years, the whole western world was under the influence of Greek-Roman mythology. Classical Greek mythology provided names like Daphne, Phoebe, Cynthia, and Jason.

3 Literature. Take Shakespeare as an example. Because of the great influence of him, many people like to choose names from his works. He provided Miranda, Jessica and Cordelia, and so on.

4 Natural environment. In several millenniums years of human civilization, people’s lives have close relation with the natural environment. So, there are also many first names originated from animals and plants. Such as Bird, Fox, Goose, Fish, and Bush, Rice, Wood, Rose, and so on.

5 Foreign origins. For example such first names as Ivan originated from Russian, Albert, Adolph, Carl from German names.

范文九:与银行有关的英语文章 投稿:郑螠螡

Banking market positioning in Luxembourg

A large number of players in international banking and investment management are present today in Luxembourg, and many of them have succeeded in enlarging and diversifying their Luxembourg operations.

Today, the financial sector accounts for over 25% of the GDP of the Grand Duchy. It is unchallenged that Luxembourg relies on an international renown and has what it takes to assert its competitiveness in Europe and beyond. In order to keep up with new market needs and constraints, players in the marketplace are reviewing the adequacy of their business model as well as the efficiency of their services and organization to meet clients and shareholders’ expectations.

The key strategy of local financial institutions is to target and serve international private and corporate investors with high value-added products and services. For this reason, the marketplace continues to provide the European financial market with innovative international solutions including securitization vehicles, private equity structures, real estate vehicles, cross-border pension funds and hedge funds, which have strongly benefited from a longstanding quality infrastructure and considerable expertise.

Business case #1

The issue

The parent company requested that its various Luxembourg entities align their strategy with that of the Group and improve

Our approach

1. Reassessment of the strategy for each subsidiary in Luxembourg for both local market and within the Group, taking into account (amongst other) the following activities: private banking, corporate banking, capital markets, lending, asset management, custody, company domiciliation and life insurance.

2. Identification of non-profitable activities, existing activities to be reinforced and new activities to be developed.

3. Definition of the most efficient business model from a regulatory, tax and organizational perspective. The analysis focused on whether one single entity or various entities should be set up and on the underlying organizational and tax impacts.

The outcome

A new strategy: a reshaping of the organizational structure, client targeting, and product and service offering.

Business case #2

The issue

A banking Group was considering the transfer of its Luxembourg activities to various other locations. The challenge of the Luxembourg bank was to identify products and services which would complement those marketed by the Group, by leveraging the opportunities that Luxembourg has to offer.

Our approach

1. Review of the current market strategy (business activities, client segmentation, product and service offering, and pricing).

2. Review of the existing organization (processes, human resources and systems) in the light of best market practices.

3. Positioning of the bank within the Group and understanding of the existing and potential synergies to be created.

4. Market analysis and identification of new value-added activities, products and services.

5. Assessment of the impacts of the divestments and new activities from several perspectives: -


- Regulatory (e.g. definition of the best legal structure to support the new activities identified) Tax (e.g. tax structuring opportunities) Operational (e.g. definition of new competences and IT requirements).

6. Definition of a business case and action plan.

7. Obtaining clearance from the Luxembourg Tax Authorities on the bank’s tax positioning in the light of the new business model.

The outcome

Repositioning of the Luxembourg entity within the Group with a new and clear mission statement, leveraging the business opportunities offered by the financial marketplace:

1. Allocation of new market responsibilities.

2. Significant improvement of financial ratios.

3. Improvement of tax positioning.

4. Hiring of additional staff.

Your current challenges

Performance: As a subsidiary of an international financial Group, you are under pressure to achieve ambitious Group performance targets;

Group positioning: You find it difficult to positively differentiate your Bank within the overall Group strategy and there is no clear strategy or mission statement for Luxembourg;

Differentiation: You are competing with other Group entities in the same markets for the same clients;

International expansion: As a foreign financial Group you want to expand in Europe and beyond and you are wondering how Luxembourg could contribute to this strategy;

Innovation and development: You want to take advantage of Luxembourg’s opportunities while strengthening your competitive position on the Luxembourg financial marketplace.

Luxembourg opportunities

1. A prime international business location and a neutral place to reach international investors.

2. Leading international private banking centre in the Euro land and second-largest fund industry

after the US.

3. A legitimate privacy and confidentiality regime.

4. A dynamic environment, constantly seeking new ways of servicing investors via the

Professionals of the Financial Sector (PFS).

5. An increasing client base formed by international companies.

6. An innovative financial laboratory.

7. An international financial investment expertise.

8. A market-responsive legal and regulatory environment.

9. A highly regulated financial market with strong customer protection rules.

10. A favorable corporate and personal tax regime.

Our solutions

1. Diagnostic

We will take an objective snapshot and conduct an initial analysis of your organization through:

A benchmark of your organization against your peers and best practices; The identification of business and operational opportunities for improvement within your organization and at Group level; A financial analysis that will disclose the true performance of your organization; A SWOT analysis including your current positioning versus competitors and your Group (based on criteria such as size, profitability, businesses, organization, relationships with Group and network).

2. Vision

We will assist you in developing a strategy for your organization in Luxembourg through:

The identification of Luxembourg market opportunities tailored to your organization; Relevance of these opportunities for your bank, as well as for your Group in terms of synergies to be created; Identification of key financial, tax and regulatory issues and opportunities; Assistance in selecting opportunities.

3. Business case

We will assist you in building and defending the business case through:

The definition of a service offering, a business model, an organization as well as target clients, systems and competencies; A feasibility study (legal, regulatory, tax and operational analysis); The drafting of a business plan; The issuance of recommendations.

范文十:与辐射有关的英语文章 投稿:莫溊溋

Latest reports from Japan reveal a country drowning in sorrow from last week’s devastating earthquake and tsunami, and it will now have to give undivided attention to a disaster of surging radiation levels at Fukushima’s Daiichi nuclear facility.

Scientists are warning that the fires associated with explosions at the Daiichi nuclear plant, where fuel storage pools have overheated, may be letting off radioactive steam.

David Lochbaum, nuclear engineer at the Union of Concerned Scientists, said: “If the spent fuel pool is on fire, the chances of radioactivity getting to the public are very much higher,” the reports.

Lochbaum said a shutdown last year at the No. 4 reactor led to the emptying of its reactor core into the spent fuel pool. “There is much more material there because there is at least one reactor core plus what there was to start with, and it is in a building that has a big hole in the side of it.”

According to , there are no longer flames at the No. 4 reactor which exploded on Tuesday. Workers have been attempting to clear debris for road construction so fire trucks can access the Daiichi complex.

But news about a crack appearing at another reactor unit sparked more concerns about the plant. The New York Times the damage at the No.3 reactor "worsened the already perilous conditions at the plant, a day after officials said the containment vessel in the No. 2 reactor had also cracked."

The Japanese government still insists the radiation levels discharging from the Fukushima site are low. “People would not be in immediate danger if they went outside with these levels. I want people to understand this,” Chief Cabinet Secretary Yukio Edano said in a televised news conference, Reuters reports.

Latest reports from call the brewing nightmare a “specific incident,” defining it as an Extraordinary increase of radiation dose at site boundary.

TEPCO also reports there are no longer signs of fire at the No. 4 reactor

The Japanese government has instructed evacuations for those within a 20km radius of the site, and all citizens within a 30km radius of the site should remain indoors. That area involves some 140,000 people.

High radiation levels at the site prevented a helicopter from a planned operation of dropping water on No. 3 reactor’s fuel rods, in an attempt to cool them.

The No. 3 reactor is now the priority, as Reuters reports it is the only reactor at Daiichi using plutonium in its fuel mix. Plutonium is highly toxic to humans, lingering for years in bone marrow and liver, leading to cancer.

High winds have also hindered attempts at using helicopters for dropping water and boric acid at the No. 4 reactor in an effort at slowing the nuclear reaction, even as Edano indicated doubts of that plan.

“It's not so simple that everything will be resolved by pouring in water. We are trying to avoid creating other problems,” Edano said, the Guardian reports.

“We are actually supplying water from the ground, but supplying water from above involves pumping lots of water and that involves risk. We also have to consider the safety of the helicopters above,” Edano added.

Emperor Akihito made his first public comments since last Friday’s Tohoku-Taiheiyou-Oki Earthquake.

“I am deeply concerned about because it is unpredictable,” he said on live television. “With the help of those involved I hope things will not get worse,” according to the Guardian.

Winds at the Daiichi plant on Wednesday were blowing offshore, pushing any contamination over the Pacific Ocean.

Many flights to Tokyo have been halted or rerouted over fear of increased radiation levels. On Wednesday, Australia and France have urged their nationals to depart the country.

Adding to the devastating plight of Japan’s citizens, a cold front moved through the region, dumping snow in some of the heaviest-hit areas of the earthquake and tsunami.

Health effects of radiation exposure Concern remains over the potential effect on human health from radiation leaks at the stricken Fukushima Daiichi nuclear plant.

A 20km (12 mile) evacuation zone affecting about 70,000 people has been imposed around the plant, and is being extended to five communities outside the zone to the north west of the plant, where radioactive contamination is most significant.

Residents living within 30km (18 miles) have been advised to leave the area, or to stay indoors, and try to make their homes airtight.

Experts believe that swift action of this sort should have minimized the risk to human health, but there are worries about the level of radiation to which emergency workers have been exposed, and about possible contamination of food and water supplies.

What are the immediate health effects of exposure to radiation?

Exposure to high levels of radiation - above one gray (the standard measure of the absorbed dose of radiation) - can result in radiation sickness, which produces a range of symptoms.

Nausea and vomiting often begin within hours of exposure, followed by diarrhoea, headaches and fever.

After the first round of symptoms, there may be a brief period with no apparent illness, but this may be followed within weeks by new, more serious symptoms.

At higher levels of radiation, all of these symptoms may be immediately apparent, along with widespread - and potentially fatal - damage to internal organs.

Exposure to a radiation dose of four gray will typically kill about half of all healthy adults.

For comparison, radiation therapy for cancer typically involves several doses of between one and seven gray at a time - but these doses are highly controlled, and usually specifically targeted at small areas of the body.

A sievert is a gray weighted by the effectiveness of a particular type of radiation at causing damage to tissues, and is used to measure lower levels of radiation, and for assessing long-term risk, rather than the short-term acute impact of exposure. There are 1,000 millisieverts (mSv) in a sievert.

People are exposed on average to around 2mSv of radiation a year from the natural environment, although there is considerable variation in this dose between individuals.

In the UK, the legal limit for radiation exposure from sources such as nuclear plants for members of the public is 1mSv a year, based on recommendations from the International Commission on Radiological Protection.

For emergencies, the upper limit is set higher - 5mSv or more - but these figures are set conservatively, at levels far below those that would significantly raise health risks.

How is radiation sickness treated?

The first thing to do is to try to minimize further exposure to contamination by removing clothes and shoes, and gently washing the skin and hair with soap and water.

Drugs are available that increase white blood-cell production to counter any damage that may have occurred to the bone marrow, and to reduce the risk of further infections due to immune-system damage.

There are also specific drugs that can help to reduce the exposure of internal organs caused by radioactive material by speeding up its removal from the body.

How does radiation have an impact on health?

Radioactive materials decay spontaneously to produce ionising radiation, which has the capacity to cause significant damage to the body's internal chemistry, breaking the chemical bonds between the atoms and molecules that make up our tissues. Damage to the DNA of a cell is particularly important.

The body responds by trying to repair this damage, but at high doses it is too severe or widespread to make repair possible, leading to short-term acute health effects.

There is also a danger of mistakes in the natural DNA repair process, which can lead in the long-term to cancer. Regions of the body that are most vulnerable to acute radiation damage include the cells lining the intestine and stomach, and the blood-cell producing cells in the bone marrow.

The extent of the damage caused is dependent on how long people are exposed to radiation, and at what level.

What are the most likely long-term health effects?

Cancer is the biggest long-term risk. Usually when the body's cells reach their "sell-by date" they commit suicide. Cancer results when cells lose this ability, and effectively become immortal, continuing to divide and divide in an uncontrolled fashion.

The body has various processes for ensuring that cells do not become cancerous, and for replacing damaged tissue.

But the damage caused by exposure to radiation can completely disrupt these control processes, raising the risk of cancer.

Failure to properly repair the damage caused by radiation can also result in changes - or mutations - to the body's genetic material (DNA), which are not only associated with cancer, but may also be potentially passed down to offspring, leading to deformities in future generations. These can include smaller head or brain size, poorly formed eyes, slow growth and severe learning difficulties.

Radiation and cancer

 Most experts agree even low doses of ionizing radiation can increase the risk of cancer - this risk becomes clear at doses above 100 millisieverts - but by a very small amount. In general, the risk of cancer increases as the dose of radiation increases. Exposure to one sievert of radiation spread out over time is estimated to increase the lifetime risk of fatal cancer by around 5% on average. The thyroid gland and bone marrow are particularly sensitive to ionizing radiation,

especially in children.

 Leukaemia, a type of cancer that arises in the bone marrow, is the most sensitive radiation-induced cancer. Leukaemia may appear as early as a few years after radiation exposure. Other cancers can also result from exposure to radiation, but may not develop for What risk does Fukushima pose currently?

The Japanese authorities have recorded a radiation level of up 400 millisieverts per hour at the nuclear plant itself.

Professor Richard Wakeford, an expert in radiation exposure at the University of Manchester, said exposure to a dose of 400 millisieverts was unlikely to cause radiation sickness - that would require a dose of around twice that level (one sievert/one gray).

However, it could start to depress the production of blood cells in the bone marrow, and was likely to result in a lifetime risk of fatal cancer of 2-4%. Typically, a Japanese person has a lifetime risk of fatal cancer of 20-25%.

A dose of 400 millisieverts is equivalent to the dose from 20 -100 CT scans.

Prof Wakeford stressed only emergency workers at the plant were at risk of exposure to such a dose - but it was likely that they would only be exposed for short periods of time to minimize their risk.

The upper limit of their exposure during this emergency is 250 millisieverts - around 12 times the normal permitted annual exposure limit in the workplace.

The lower legs of two workers came into contact with highly contaminated water, which led to a high localized dose to the skin (1-2 gray) that was sufficient to cause temporary skin reddening. The dose to the trunks of their bodies was much less, at 100-200 mSv.

However, even a dose of 100 millisieverts over a year is enough to raise the risk of cancer, and a dose of 250 millisieverts could produce an additional lifetime risk of around 1-2%.

The level of exposure for the general population, even those living close to the plant, was unlikely to be anywhere near as high.

However, levels equivalent to around 25 millisieverts a year have been recorded in the village of Iitate, to the north west of the plant. Professor Wakeford said estimating the impact on human health of such a level was difficult, but there was some evidence to suggest that it could raise the risk of cancer - albeit by a small amount.

The pattern of contamination around the plant is patchy, reflecting wind direction and rainfall at the time of any release. The risk to people living in less contaminated communities will be much lower than the areas to the north-west of the plant.

What radioactive materials have been released?

Experts are concerned about two types of radioactive material, created as by-products of the nuclear fission process, both of which are easily released and can contaminate the soil relatively easily, and get into the food chain. This is why foodstuffs sourced from some areas have been banned.

The radioactive form of iodine - iodine-131 - is easily absorbed by the thyroid, the gland which regulates growth and cell production.

This would raise the risk of thyroid cancer in those exposed as children.

To counter that risk, people - in particular children - can be given tablets containing a stable form of iodine which would prevent the body absorbing the radioactive version.

Radioactive iodine decays quite quickly and will disappear from the environment within weeks or months.

The Japanese already have a lot of iodine in their natural diet, so that should help too.

Another potential source of contamination is the radioactive form of the metal cesium (caesium-134 and caesium-137), which once released into the environment continues to pose a potential risk for many years.

Unlike iodine, cesium does not concentrate in one particular tissue, but gets into soft tissues, where it can cause cancer.

How can the Japanese authorities minimize the cost to human health?

Prof Wakeford said that provided the Japanese authorities acted quickly, most of the general population should be spared significant health problems.

He said in those circumstances the only people likely to be at risk of short-term serious health effects were emergency workers at the plant potentially exposed to high levels of radiation.

The top priority would be to evacuate people from the area and to make sure they did not eat food contaminated above the limit.

Distribution of iodine pills would also help to minimize the risk of thyroid cancer in the general population should high levels of radioactive iodine be present in the environment.

Is there evidence that food has been contaminated?

Yes. Japan's health ministry has urged some residents near the plant to stop drinking tap water after samples showed elevated levels of radioactive iodine - about three times the limit in Japan.

Radioactive iodine has also been found in water supplies in Tokyo at twice the levels deemed safe in Japan for babies and infants to drink, although still some way short of the safety level for adults. Raised radiation levels have also been found in samples of milk and spinach, in some cases well outside the 20km exclusion zone, particularly to the north west of the plant.

Japan's chief cabinet secretary Yukio Edano, said the level of radioactivity found in the spinach would, if consumed for a year, equal the radiation received in a single CT scan. For the milk, the figure would be much less.

Professor Wakeford stressed that safe limits in Japan for radiation in food were kept very low and assumed long-term consumption, so people should not necessarily be unduly worried by reports that they had been breached.

For instance, an infant would have to drink over 100 liters of water containing iodine-131 at the limit to reach the dose of radiation received in a year from natural background sources.

However, Professor Wake ford said it would be advisable to stop young children from eating products contaminated over the limit. But he stressed that contamination levels have fallen sharply since mid-March.

What is the threat to Tokyo residents from contaminated tap water?"

Officials said the tap water showed 210 Becquerel per liter of iodine-131 - more than twice the recommended limit of 100 Becquerel per liter for infants. The recommended limit for adults is 300 Becquerel per liter. (Becquerels is a measure of radioactivity whereas millisieverts is a measure of dosage to the body of the radiation emitted on radioactive decay).

Professor Richard Wakeford says that infants who drank 100 litres of water contaminated at the Japanese limit of 100 Becquerel of iodine-131 per litre would receive a radiation dose of about 2 millisieverts of radiation.

The Japanese limit for adults is 300 becquerels of iodine-131 per liter because adults are less sensitive to the effects of radiation.

In comparison, the average person is exposed to 2-2.5 millisieverts from natural background radiation in a year, although variations about this average can be large.

In theory, drinking water contaminated at 210 Becquerel of iodine-131 per liter for a year would cause a very small additional risk of cancer - but in practice nothing much more than you could expect to get from normal background levels of radiation.

Is it safe to bathe or wash food in contaminated tap water?

Yes, because only small amounts of water would be ingested into the body from these practices.

What about contaminated seawater?

Levels of radioactive iodine-131 in seawater near the nuclear plant have reached 3,355 times the legal safety limit, but this limit is set at a very low level for normal operations.

Japanese officials admitted the reading was a concern - but said there was no immediate threat to human health.

Professor Wakeford said it would be sensible to ensure that fish and other seafoods contaminated beyond the limit did not enter the food chain.

However, he stressed that radioactive iodine would be diluted by the ocean currents, and would, in any case, decay away almost completely within three months.

How does Fukushima compare to Chernobyl?

Although Japan's Nuclear Safety Commission has upgraded the severity rating of the crisis from five to seven, the highest level and the same as Chernobyl, officials say emissions of radioactive materials at Fukushima currently stand at about 10% of those from the 1986 disaster.

Professor Gerry Thomas, who has studied the aftermath of the Chernobyl disaster, said: "It is very unlikely that this will turn into anything that resembles Chernobyl.

"In Chernobyl you had a steam explosion which exposed the reactor core, which meant you had a lot of radiation shooting up into the atmosphere."

Prof Thomas said although the Chernobyl disaster had led to a rise in thyroid cancer cases, the only people affected were those living in the areas of Ukraine, Belarus and Russia that lie closest to the site of the Chernobyl Power Plant, and who were young at the time.

What if the situation deteriorates?

If there were to be a meltdown or a fire at the nuclear plant, and unfavourable winds, then experts say radioactive material could reach as far as Tokyo, 150 miles (241km) away.

However, even in that situation, the level of radiation is likely to be such that simple measures, such as staying indoors with windows closed, should significantly reduce the risk.

The situation is much better now than at the time of the major earthquake on 11 March because the short-lived radioactive materials have decayed away - the radioactivity of iodine-131, a major concern in releases from the site, reduces by a half every eight days, so in a month there is only one-sixteenth of the original iodine-131 left.