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Please Fasten Your SeatbeltsSevere turbulence（湍流）can kill aircraft passengers.Now,in test flights over the Rocky Mountains, NASA（美国航空航天局）engineers have successfully detected clear-air turbulence up to 10 seconds before an aircraft hits it.Clear-air turbulence often catches pilots by surprise.Invisible to radar,it is difficult to forecast and can hurl（用力抛出去）passengers about the cabin.In December 1997 , one passenger died and a hundred others were injured when unexpected rough air caused a United Airlines flight over the Pacific to drop 300 meters in a few seconds.However,passengers can avoid serious injury by fastening their seatbelts."It is the only antidote（对 策）for this sort of thing,"says Rod Bogue, project manager at NASA's Dryden Flight Research Center in Edwards,California.The Center's new turbulence detector is based on lidar,or laser-radar.Laser pulses are sent ahead of the plane and these are then reflected back by particles in the air.The technique depends on the Doppler Effect（多普勒效应）.The wavelength of the light shifts according to the speed at which the particles are approaching.In calm air,the speed equals the plane's airspeed.But as the particles swirl（打漩） in rough air,their speed of approach increases or decreases rapidly.The rate of change in speed corresponds to the severity（激烈程度）of the turbulence.In a series of tests that began last month,a research jet flew repeatedly into、 disturbed air over the mountain ridges（山脉）near Pueblo , Colorado.The lidar detector spotted turbulence between 3 and 8 kilometers ahead, and its forecasts of strength and duration corresponded closely with the turbulence that the plane encountered.Bogue says that he had"a comfortable amount of time"to fasten his seatbelt.The researchers are planning to improve the lidar's range with a more powerful beam.The system could be installed on commercial aircraft in the next few years. The turbulence detector can tell the severity of the turbulence by measuring______.
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第一篇Food PoisoningFood sometimes gets poisoned with harmful things,A person who eats such food can get an illness called food poisoning. Food poisoning is usually not serious,but some types are deadly.The symptoms of food poi- soning usually begin within hours of eating the poisoned food.Fever is one of the most common symptoms.Certain microorganisms（微生物）cause most types of food poisoning. Bacteria and other microorganisms can poison eggs,meat,vegetables,and many other foods.After entering the body,these tiny living things re- lease（释放）poisons that make people sick.Some chemicals can also cause food poisoning. They are often added to food while it is being grown,pro- cessed,or prepared.For example,many farmers spray chemicals on crops to kill weeds and insects.Some people may have a bad reaction to those chemical、when they eat the crops.Some plants and animals contain natural poisons that are harmful to people.These includo certain kinds of seafood,grains,nuts,seeds,beans,and mushrooms.When people handle food properly,the risk of food poisoning is very small.Microorganisms multiply rapidly in dirty places and in warm temperatures.This means that people should never touch food with dirty hands or put food on unwashed surfaces.Food should be kept in a refrigerator to stop microorganisms from growing, Meat needs to be cooked thoroughly to kill any dangerous microorganisms. People should also wash food covered with chemicals before eating it.Finally,people should not eat wild mushrooms or other foods that grow in the wild.Some of these foods may contain natural materials that are poisonous to humans.In addition,some types of fish can be poisonous.Most people recover from food poisoning after a few days of resting and drinking extra water. If people eat natural poisons,they must go to the hospital right away to have their stomachs emptied.
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Rescue PlatformIn the aftermath of the terrorist attacks on the World Trade Center,security experts are trying to develop new ways of rescuing people from burning skyscrapers.One________(51)is a plat-form capable of flying vertically and hovering in the air_________(52)a helicopter. The plafform would rise up and down alongside a skyscraper and pick up people_________(53)in high stories。The idea for the vertical takeoff platform was hatched（策划）more than ten years ago by a Russian aerospace engineer,David Metreveli,who has since moved to Israel. Metreveli's design, _________(54)the Eagle,calls for two jet engines that_________(55)four large horizontal pro-pellers. The spinning of the propellers_________(56)the necessary lift,or upward force,to raise the platform. The more_________(57)is supplied to the propellers,the higher the platform _________(58).Moving the platform sideways involves_________(59)differing amounts of power to each propeller.Helicopters are now used in some________(60)to get people out of burning buildings.Es-cape baskets slung from them dangle beside the building for people to climb into._________(61),the baskets cannot reach every floor of a building_________(62)the ropes from which they hang become unstable_________(63)a certain length.So far,Metreveli has built a small-scale model of the Eagle to_________(64)his idea. In the wake of September 11,he has been able to secure enough funding to start building a larger ,4- meter by 4-meter prototype,_________(65)he calls the Eaglet. 55._________
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Google's Solar Energy Gambit（策略）Google is making its largest investment yet in clean energy,setting up a $280 million fund to finance home solar rooftop（屋顶）installations.The search giant announced today it was teaming up with the Silicon Valley's Solar City一a company chaired by Paypal co-founder and Tesla Motors executive Elon Musk一in an effort to break down the biggest barrier to solar energy adoption:the cost."It's a great way to support installations going into more homes,"said Google spokesperson Parag Chokshi.The $280 million fund is the largest fund ever created for residential solar in the United States,according to Solar City,which has raised a total of$I.28 billion in financing capacity during its five-year history.Google over the past several years has invested in large,utility-scale wind and solar,enhanced geothermal（地热）energy,and other renewable energy projects,for a grand total of more than $680 million in the sector. But today's deal is not only Google's largest foray（突袭）into the sector, it is its first investment in distributed energy. Based in San Mateo,California,less than 20 miles north of Google's Mountain View headquarters,Solar City describes itseff as a solar power service provider. The idea is that people want affordable,clean energy一but they often can't afford to buy a photovoltaic system upfront. Solar City is one of a number of companies that have attempted to help people overcome that cost hurdle（障碍）by leasing,instead of owning their rooftop solar systems.Solar City's leases and power-purchase agreements to homeowners,businesses,and schools promise a lower monthly electricity bill(including a set payment to Solar City in addition to utility payments)than customers would get with their usual electricity from the grid.Solar City not only finances these photovoltaic projects,but also designs,installs,monitors,and maintains the systems. Recently,since buying the assets of a company called Business Solutions last year,Solar City has also begun offering energy audits and small home improvements(like installing programmable thermostats)that can make a big difference in energy use.Until now,Solar City has financed most of its 15,000 projects through banks,Chief Executive Lyndon Rive said in an interview. But the problem is only about a half dozen banks are doing solar financing,he said.So in order for Solar City's model to achieve"true scale,"it must"unleash the available capital of corporate America,"he said.Rive is hopeful that Google's move today will set an example for other corporations to make similar investments.
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第一篇Graphene' s SuperstrengthBig technology comes in tiny packages.New ccii phones and personal computers get snialler every year, which means these electronics require even smaller components on the inside.Engineer; are looking for creative ways to build these components,and they'ye turned their eyes to graphene,a superthin material, made of carbon,that could change the future of electronics.This year's Nobel Prize for Physics has been awarded to Andre Geim and Kostya Novoselov from the University of Manchester,U.K.for the discovery of graphene.Graphdne isn't just small;it's "the thinnest possible material in this world"says Novosclov.iJe calls it a “wonder material".It’s so thin that you would need to stack about 25,000 sheets just to make a pile as thick as a piece of' ordinary white paper. If you were to hold a sheet of graphene in your fingers,you'ci have no idea because you wouldn't be able to see it.Carbon is one of the most abundant elements in the universe.Every known kind of life contains carbon. Graphene is a sheet of earboti,but only one atom thick.You don't have to look far to find graphene一it's all around you.If you want this high-tech wonder stuff,all you need is a pencil,paper and a little adhesive tape.Use the pencil to shade a small area on the paper,and then apply a small piece of adhesive tape over the area. When you pull up the tape,you'll see that it pulls up a thin layer of some of the shading from your pencil. That layer is called graphite,one of the softest mninerals in the world.Now stick the same piece of tape on another sheet of paper and pull the tape up一there should be an even thinner layer,this time left on the paper. Now imagine that you do this over and over,until you get the thinnest possible layer of material on the paper. This layer would he only one atom thick,and you wouldn't be able to see it. Graphite is made of layers of graphene.So when you get to the thinnest possible layer, you've found graphene.
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Animal's"Sixth Sense"A tsunami was triggered by an earthquake in the Indian Ocean in December,2004.It killed tens of thou- sands of people in Asia and East Africa. Wild animals,______________(51),seem to have escaped that terrible tsunami.This phenomenon adds weight to notions that they possess a"sixth sense"for______________(52),cx-perts said.Sri Lankan wildlife officials have said the giant waves that killed over 24,000 people along the Indian Ocean island's coast clearly______________(53)wild beasts,with no dead animals found."No elephants are dead,not______________(54)a dead rabbit.I think animals can______________(55) disaster.They have a sixth sense.They know when things are happening."H.D.Ratnayake,deputy director of Sri Lanka's Wildlife Department,said about one month after the tsunami attack.The______________(56) washed floodwaters up to 2 miles inland at Yala National Park in the ravaged southeast,Sri Lanka's biggest wildlife______________(57)and home to hundreds of wild elephants and several leopards."There has been a lot of______________(58)evidence about dogs barking or birds migrating before vol- came eruptions or earthquakes.But it has not been proven,"said Matthew van Lierop an animal behavior ______________(59)at Johannesburg Zoo."There have been no______________(60)studies because you can't really test it in a lab or field set-ting,"he told Reuters.Other authorities concurred with this______________(61)."Wildlife seem to be able to pick up certain______________(62),especially birds…there are many re-ports of birds detecting impending disasters."said Clive Walker,who has written several books on African wildlife.Animals_______________(63)rely on the known senses such as smell or hearing to avoid danger such as predators.The notion of an animal"sixth sense”-or_______________(64)other mythical power一is an enduring one which the evidence on Sri Lanka's ravaged coast is likely to add to.The Romans saw owls______________(65)omens of impending disaster and many ancient cultures viewed elephants as sacred animals endowed with special powers or attributes. _________(54)
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Citizen ScientistsUnderstanding how nature responds to climate change will require monitoring key life cycle events-flowering,the appearance of leaves,the first frog calls of the spring-all around the world.But ecologists can't be______(51)so they are turning to non-scientists,sometimes called citizen scientists,for help.Climate scientists are not present everywhere.______(52)there are so many places in the world and not enough scientists to observe all of them,they are asking for your help in_______(53)signs of climate change across the world.The citizen scientist movement encourages______(54)people to observe a very specific research interest-birds,trees,flowers budding,etc-and send their observations______(55)a giant database to be observed by professional scientists.This helps a small number of scientists track a______(56)amount of data that they would never be able to gather on their own.______(57)like citizen journalists helping large publications cover a hyper-local beat,citizen scientists are ready for the conditions where they live.______(58)that's needed to become one is a few minutes each day or each week to gather data and_______(59)it in.A group of scientists and educators launched an organization last year______(60) the NationalPhenology（生物气候学）Network."Phenology" is what scientists call the study of the timing of events in nature.One of the group's first efforts relies on scientists and non-scientists______(61)to collect data about plant flowering and leafing every year.The program,called Project BudBurst,collects life cycle______(62)on a variety of common plants from across the United States.People participating in the project-which is______(63)to everyone-record their observations on the Project BudBurst website."People don't______(64)to be plant experts-they just have to look around and see what's in their neighborhood,"says Jennifer Scheartz,an education consultant with the project."As we collect this data,we'11 be able to make an'estimate of______(65)plants and communities of plants and animals will respond as the climate changes." _________64
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Citizen ScientistsUnderstanding how nature responds to climate change will require monitoring key life cycle events-flowering,the appearance of leaves,the first frog calls of the spring-all around the world.But ecologists can't be______(51)so they are turning to non-scientists,sometimes called citizen scientists,for help.Climate scientists are not present everywhere.______(52)there are so many places in the world and not enough scientists to observe all of them,they are asking for your help in_______(53)signs of climate change across the world.The citizen scientist movement encourages______(54)people to observe a very specific research interest-birds,trees,flowers budding,etc-and send their observations______(55)a giant database to be observed by professional scientists.This helps a small number of scientists track a______(56)amount of data that they would never be able to gather on their own.______(57)like citizen journalists helping large publications cover a hyper-local beat,citizen scientists are ready for the conditions where they live.______(58)that's needed to become one is a few minutes each day or each week to gather data and_______(59)it in.A group of scientists and educators launched an organization last year______(60) the NationalPhenology（生物气候学）Network."Phenology" is what scientists call the study of the timing of events in nature.One of the group's first efforts relies on scientists and non-scientists______(61)to collect data about plant flowering and leafing every year.The program,called Project BudBurst,collects life cycle______(62)on a variety of common plants from across the United States.People participating in the project-which is______(63)to everyone-record their observations on the Project BudBurst website."People don't______(64)to be plant experts-they just have to look around and see what's in their neighborhood,"says Jennifer Scheartz,an education consultant with the project."As we collect this data,we'11 be able to make an'estimate of______(65)plants and communities of plants and animals will respond as the climate changes." _________58
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Computers in CarsYou're far from home on a lonely road .Shadowy forests stretch away on both sides. A thick mist（雾）makes it difficult to see far beyond your car's windshield（挡风玻璃）.“Can this be route 90A?”you wonder. if it is,you should be near a town. Yet there's no hint of one.Night is closing in. And you're low on gasoline.This is a situation where an in-car computer that can navigate would be a big help.A car computer that navigates?Yes!Such computers exist. Several experimental models are being tested by General Motors,Ford,Chrysler,and several foreign car makers.These computers vary in detail.But they all contain series of maps on videodiscs or videotapes.For example,one computer system contains 13,300 maps covering the continental US.Before starting out on a trip,a driver can type in the code for the region he or she plans to drive through.The computer then shows a map of that region. At the same time,a tiny radio re-ceiver linked to the computer goes to work.It picks up signals from navigation satellites such as the NAVSTAR network.Using these signals,the computer shows the car's position at all times and displays this position on the map.The computer can also calculate and display the best route to follow.A navigation computer may also receive and use data about road construction,weather condi-tions,and traffic jams. This information would be displayed to the driver and the computer would also use the information to work out alternate（交替的）routes.Most cars nowadays also contain computers that help cars run more efficiently. Microproces- sors（微处理机）control certain engine functions by regulating the mixing of fuel. Data on car speed,oil pressure,revolutions per minute,engine temperature,and fuel level can be displayed as digital data(numbers)or warning lights.Some auto designers suggest that a central computer display be used to clearly present such timely information as car speed and fuel level.Warning lights would indicate a drop in oil pressure or a sudden rise in engine temperature.To get more information on these conditions,the driver could call it up on the computer display screen.When needed,the computer could be “asked”to provide navigation aid or information about the car's condition. The navigation computers have one thing in common:they all＿______.
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Older Volcanic EruptionsVolcanoes were more destructive in ancient history,not because they were bigger,but because the carbon dioxide they released wiped out life with greater ease.Paul Wignall from the University of Leeds was investigating the link between volcanic eruptions and mass extinctions.Not all volcanic eruptions killed off large numbers of animals,but all the mass extinctions over the past 300 million years coincided with huge formations of volcanic rock.To his surprise,the older the massive volcanic eruptions were,the more damage they seemed to do.He calculated the"killing efficiency"for these volcanoes by comparing the proportion of life they killed off with the volume of lava（熔 岩）that they produced.He found that size for size,older eruptions were at least 10 times as effective at wiping out life as their more recent rivals.The Peimian（二叠纪）extinction,for example,which happened 250 million years ago,is marked by floods of volcanic rock in Siberia that cover an area roughly the size of western Europe.Those volcanoes are thought to have pumped out about 10 gigatonnes（十亿吨）of carbon as carbon dioxide.The global warming that followed wiped out 80 prcent of all marine genera（种类）at the time , and it took 5 million years for the planet to recover.Yet 60 million years ago,there was another huge amount of volcanic activity and global warming but no mass extinction.Some animals did disappear but things returned to normal within ten thousands of years."The most recent ones hardly have an effect at all."Wignall says.He ignored the extinction which wiped out the dinosaurs 65 million years ago,because many scientists believe it was primarily caused by the impact of an asteroid（小行星）.He thinks that older volcanoes had more killing power because more recent life forms were better adapted to dealing with increased levels of CO
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