原标题: 黔江区印度星龟密西西比红耳龟黄头侧颈龟东部网目鸡龟价格怎么养安分享
Finance and Economics;The Big Mac index;Calories and currencies; 财经;巨无霸指数;货币卡路里;What burgernomics says about five years of turmoil汉堡经济学解读“危机五年”Our Big Mac index is back. Normally a beefy bundle of exchange rate fun, this year it is marking a sombre anniversary: five years since global money-markets seized up in the summer of 2007. What does burgernomics reveal about todays exchange rates, and about the impact that five years of distress, from credit crunch to euro crisis, have had on currencies?《经济学人》的巨无霸指数又回来啦!与往常拿厚厚一叠汇率开玩笑不同,今年是为了黯然纪念“2007年夏全球金融市场失灵”五周年。汉堡经济学该如何解读现今的汇率形势,以及五年混乱——从信贷紧缩到欧元危机对货币的影响?The Big Mac index is The Economists burger-based measure of whether currencies are over- or undervalued. The recipe comes from the theory of purchasing-power parity, which says that exchange rates should eventually adjust to make the price of a basket of goods the same in each country. Our basket contains just one item: the Big Mac hamburger, which is pretty much the same around the world.巨无霸指数是《经济学人》以汉堡价格为基础来衡量一国货币是否被高估或低估。其理论依据是购买力评价学说,该学说认为应使汇率最终调整到使各国一篮子商品的价格相同。《经济学人》的篮子里只有一样商品:巨无霸汉堡,该商品在全世界卖的几乎是一样的。The index works by calculating the exchange rate that would leave a Big Mac costing the same in each country. Take the rouble and the real, the currencies of Russia and Brazil respectively. At current exchange rates a Big Mac, which sells for 4.33 dollor in America, costs just 2.29 dollor (75 roubles) in Russia, whereas in Brazil it sells for a sliver under 5 (10 reais) dollor. So the dollar buys a lot of burger in Russia, signalling that the rouble is cheap and the real rather pricey. A selection of other currencies is included in the chart (the full index can be seen here).巨无霸指数的作用在于计算出使各国汉堡价格相同的汇率。以俄罗斯货币卢布和巴西货币雷亚尔为例。在当前汇率下,一个巨无霸在美国售价为4.33美元,在俄罗斯仅售2.29美元(75卢布),然而巴西的售价略低于5美元(10雷亚尔)。所以美元在俄罗斯可以买到许多汉堡,这说明卢布比较便宜而雷亚尔相当昂贵。该图表显示了其他代表性货币情况(要看完整的巨无霸指数请点这里)In addition to the real, several other currencies look dear, according to the latest Mcdata. A group of rich European countries—none of them in the euro zone—sit near the top of the pile. At the other end, the yen, the pound and the Canadian dollar all look cheap. But it is in Asia that you get the most burger for your buck: China, Indonesia and Hong Kong are all more than 40% undervalued.根据美国麦迪数据公司最新数据显示,除了雷亚尔,其他几种货币也表现得昂贵。一批富裕的欧洲国家——都没有加入欧元区——处在排行的前列。另一端,日元、英镑、以及加拿大元都表现的廉价。然而在亚洲买汉堡才是最划算:中国、印度尼西亚、和中国香港的货币都低估了40%以上。There have been some big shifts in fortune since the first rumblings of the crisis, five years ago. The Australian dollar has strengthened, moving from 14% undervalued to 8% overvalued. In the early part of the crisis Australias well-capitalised banks proved remarkably resilient; more recently, the currency has benefited from a spike in commodities prices (see article), and from strong exports to China. Japan and Brazil also have beefier currencies than five years ago.自五年前经济危机伊始,全球财富进行了一些大洗牌。澳元走强,从低估40%升至高估8%。在危机早期,澳洲资本雄厚的显著地明了自己具有弹性。最近,澳元又受益于大宗商品价格飙升,以及对中国强劲的出口。日本和巴西的货币也比五年前更坚挺。Others have weakened. The British pound is a shadow of its former self: since 2007 it has moved from 18% overvalued to 4% undervalued. Britains experience has been the opposite of Australias: its financial industry, a big chunk of the overall economy, was at the heart of the financial turmoil (the pound depreciated sharply in 2008) and its biggest export market, the euro zone, is in a dful mess.其他货币则变得疲软。英镑沦落为从前自己的影子:自2007年起从高估18%跌落至低估4%。英国的经历恰与澳大利亚相反:占英国总体经济大部分的金融业处于金融风暴的中心(2008年英镑急剧贬值),而它最大的出口市场欧元区正一团糟。Being at the bottom of the Big Mac index need not be all bad, though. A cheap currency means exports look attractive to foreigners. Slipping down the index should, in theory, boost net exports. China manages its currency using exactly this logic: to keep the yuan cheap and demand for yuan-priced exports high.不过处在巨无霸指数的底部也不全是坏事。便宜的货币意味着出口在外国人眼里更有吸引力。理论上,巨无霸指数上的下滑可以促进净出口。中国对人民币的管制正是出于这一逻辑:保持人民币价格低,就可以保以人民币计价的出口需求大。Now the biggest exchange rate move economists are hoping to see is a marked fall in the value of the euro. The euro zone, in particular its sickly peripheral economies, including Spain and Greece, craves a calorific boost from the currency.如今经济学家期望看到的最大汇率变动是欧元价值的显著下滑。欧元区,特别是糟糕的经济体(包括西班牙和希腊)渴望货币能释放巨大能量,来推动经济复苏。 /201302/226857What’s So Special About A Sharp Knife?Everyone knows that a sharp knife cuts better than a dull one, but do you know why, exactly?The purpose of the cutting edge of a knife is to concentrate the force that’s being applied at the handle.When you push down on the handle of a knife you exert a force. The force on the handle and the edge are the same, but the areas in which the force is concentrated are quite different.At the handle your hand’s force is sp over a wide area, but on the cutting edge it is concentrated in a very small area, so therefore the pressure on the edge is much greater.You can easily see how this works with a piece of modeling clay, a nail with a wide head, and a nail with a small head. First hold the nail with the wide head by its shaft and push it head-first into the ball of clay. Then do the same with the small-headed nail.The small-headed nail goes into the clay much more easily than the wide-headed nail. Since the head of the small nail has less surface area than the big one, the force of your push is concentrated in a smaller area, exerts more pressure on the clay, and so the nail goes in more easily. The same principal causes pointed high-heeled shoes to sink into a soft surface more easily than flat shoes.By applying this principal to the knife you can see that with a keener edge there’s a greater concentration of the pressure on the edge, so it takes much less force to make the knife cut. /201205/184745The Blurry World Underwater水下的朦胧世界When you open your eyes underwater, things look blurry, but with goggles, everything looks perfectly clear. Why cant we landlubbers focus underwater without goggles?当你在水底睁开眼睛的时候,所有的东西看上去都很模糊,但是戴上护目镜,所有的东西看起来都变得很清晰。为什么我们水手在水底不戴护目镜就不能自动聚焦呢?First, we need to explore how our eyes focus when were high and dry. Our ability to focus depends on the refraction, or bending, of light rays as they pass between substances of different densities. One way to see refraction is to put a spoon in a glass of water. It looks like the spoon bends at the waters surface, but its really the light rays bending as they pass between the air and the denser water. A lens works in a similar way, but unlike the flat surface of water, which bends all the rays the same way, a lens is curved, bending rays at different angles so they come to a focus.首先,我们需要探索当我们处于高处和干燥的地方时,我们的眼睛是怎样聚焦的。我们聚焦的能力取决于光线通过不同密度的物质时发生的折射或者弯曲。观察到折 射现象的一种方法是在装水的玻璃杯中放入一个汤匙,汤匙在水面处看上去似乎是被折成了两段。但事实上,这是光线在通过空气和密度更高的水时发生的折射现 象。透镜以同样的方式运作。但不同的是,不像水平面使所有的光线以同样的角度折射弯曲,透镜是曲面的,这样就使得光线从不同的角度发生了弯曲,所以它们就 形成了聚焦。The front of the eye has two lenses, the cornea on the outside and another lens inside, to focus images on the retina, at the back of the eye. Most of the refraction takes place when light passes from the air into the cornea, which is much more dense, but water and the cornea have similar densities. So, when we open our eyes underwater, incoming light rays are hardly bent, or focused, at all. The inside lens bends the rays a little, but it cant make up for the lost corneal refraction, so the light that reaches the retina isnt focused and the underwater world looks blurry.在眼睛的前部有两个透镜,通过外部的角膜和另一个位于内侧的晶状体,我们得以把图像聚焦到位于眼睛后部的视网膜上。当光通过空气进入角膜时,角膜密度比空 气大,大多数折射就发生在这个时候。但是水的密度和角膜的相似,所以,当我们在水底睁开眼睛的时候,入射光线很难弯曲或者聚焦。内部的晶状体可以使光线发 生一些弯曲,但这不能弥补在角膜处失去的折射,所以到达视网膜的光无法聚焦,水底世界看起来就很模糊。Goggles clear things up by inserting a pocket of air in front of the cornea, restoring that crucial interface between substances of different densities to refract the light.护目镜可以保留在角膜前方的空气,恢复了不同浓度物质的界面,实现了光的折射,从而使我们看到的东西变得清晰。 /201207/189040

Business商业Express Scripts and Medco美国快捷药方公司与美可保健Bigger means cheaper越大越便宜A new drugs manager may change the way Americans pop their pills全新的药物管理者可能改变美国人购买药品的方式IT TOOK eight months and more than 200 interviews.花了八个多月的时间,会面达到200多次。But on April 2nd Americas Federal Trade Commission (FTC) decided, in a three-to-one vote, to let Express Scripts acquire Medco.但是4月2日,美国联邦贸易委员会以三比一的投票决定同意美国快捷药方公司收购美可保健。The two firms are Americas second-biggest and biggest pharmacy-benefit managers.两家公司合并后将成为美国第二大药品公司以及最大的药品福利管理者。Eventually, they may change the way Americans take drugs.这两家公司的合并可能最终改变美国人购买药物的方式。Despite an intolerably dull title, pharmacy-benefit managers (PBMs) are important.尽管标题无聊的令人无法忍受,但是药品福利管理者(PBMs)十分重要。America is the worlds biggest drug market; in 2010 it spent more than 7 billion on prescription medicines.美国是世界上最大的药品市场;2010年美国在处方药上的花费达到3070亿美元。PBMs are the middlemen that manage drug costs for employers and insurers. Together, Express Scripts and Medco will control more than 40% of the market.药品福利管理是是平衡雇主和保险公司之间医药费用的中间人,快捷药方公司与美可保健一起将能控制40%以上的药品市场份额。Express Scripts announced the acquisition in July 2011. Medco was a good company that had had a bad year, and so looked cheap.快捷药方公司曾宣布在2011年7月完成收购工作,美可保健去年情况不佳,看起来有点贬值,但美可保健是一个业绩不错的公司。It had lost about 30% of its business in a few months as some of its largest clients ended their contracts.由于一些大客户终止了合同,美可保健几个月内就损失了30%的生意。For both firms, bigger ought to mean better.对两家公司来说,扩大经营必须意味着良好的收益。With scale would come the power to negotiate fatter discounts on drugs, lowering costs for employers and insurers.大规模将在药品折扣问题的商讨上占有更大的优势,并降低雇佣者和保险公司的成本。Pharmacists felt sick when they heard the news.听说了这个消息之后药剂师感觉并不好。PBMs encourage consumers to fill their prescriptions through the mail instead of going to a costly pharmacy.药品福利管理者鼓励消费者通过邮件方式而不是通过花费过高的药品公司购买药物。PBMs, pharmacists fret, will crush their fees for dispensing drugs.药品福利管理者让药剂师们很头痛,药品福利管理者会把削减开处方药的费用。Worse, PBMs will demand that drugmakers give them exclusive deals for new, complex medicines.更糟糕的是,药品福利管理者要求药品制造上对于新药和合成药给与特别的折扣。Competitors and consumers will suffer, the pharmacists argue.药剂师认为竞争者和消费者都会遭受损失。The FTC disagreed.联邦贸易委员会并不这么认为。The merged firm is unlikely to squeeze pharmacies fees for dispensing drugs, it ruled.合并后的公司不可能压榨药剂师配置药物的费用,只是对此收费进行规范。There remain plenty of lively, smaller PBMs.市场中还有很多小规模活跃的药品福利管理者。John Kreger of William Blair, an investment bank, says there is enough turmoil—thanks both to the merger and to Express Scripts continuing fight with Walgreens, a big pharmacy—that smaller PBMs may snatch new business in the next year.投资William Blair的John Kreger说已经够乱了——多亏两家公司的合并,还有快捷药方公司与大型的医药公司Walgreens不断的竞争——小规模的药品福利管理者明年会抢走新业务。The small fry may also benefit if the pharmacy lobbys lawsuit against the merger moves forward.如果反对合并进程的药品游说诉讼能够成功的话,小公司也能从中获益。The combined firm will have billion in revenue in 2012, estimates Lawrence Marsh, an analyst at Barclays Capital.据巴莱克集团的分析师Lawrence Marsh预测,合并后的公司在2012年的收益能够达到910亿美元。It is so big that it could shape a new era for Americas drug market.收益如此巨大以至于可以塑造美国药品市场的新纪元。As more drugs lose their patents, consumers will increasingly fill their prescriptions with generics.由于越来越多的药品不再拥有专利权,越来越多的消费者都会使用非专利药物开具处方。If Express Scripts has its way, they will also fill their prescriptions by post.如果快捷药品公司也采用此方法,那么他们也会采取邮寄方式开药方。Medco recently acquired a firm that compares the efficacy of different drugs.美可保健最近收购了一家比较药品不同功效的公司。This may prove useful when America begins to see cheap copies of complex drugs, called biosimilars, which will be tested against the originals.美国开始看到合成药剂的复制品,即生物仿制药,价格低廉,能用来与源药品做对比试验。此时上述收购还是极为有益的。The new Express Scripts may also play a role on Barack Obamas new insurance exchanges, working with insurers to court individuals shopping for health care.新的快捷药方公司同样在奥巴马提出的新型保险交易中扮演了重要角色,他和保险代理人一起劝说个人购买健康保险。Most intriguingly, the new Express Scripts could push Americans to buy the right medicines and take them at the right time.最有趣的是新的快捷药方公司可以推动美国人在正确的时间购买正确的药物。For years PBMs have tested ways to urge consumers to buy cheaper, effective drugs.几年来,药品福利管理者尝试新的方法以促使消费者购买便宜而有效的药物,For example, if a patient wants a branded pill rather than a generic, he must pay for more of it himself.例如如果病人想购买品牌药物而非一般药物,他要为多出的费用自己掏腰包。Experiments will probably scale up and become more sophisticated.这样的试验将逐步扩大规模,也会越来越复杂。Eventually, they might even sp to Medicaid, the public programme for the poor.最终将波及医疗补助计划,该计划是救助穷人的公共计划。Health reform (unless the Supreme Court strikes it down) will add 16m new members to Medicaid by 2019, a 27% jump.到2019年,健康改革(除非最高法院将其驳回)将增加160万名新的受益者,约增长了27%。PBMs such as Medco and Express Scripts have so far spent little time chasing the Medicaid market.像美可保健和快捷药方公司这样的药品福利管理者迄今为止在医疗补助计划投入的时间还不多。That may change.这种情况可能会有所改变。 /201210/205819Vincent never said a word.文森特从没有说过一个字。When it finally came out unamazed Eugenie informed him that she was aly secretly engaged to a previous lodger,最终消息传出,不怎么感到惊讶的尤金告诉他,她已经秘密地与前一位房客订婚,an engineer called Samuel Ploughman.这是一位名叫萨穆埃尔·普拉格曼的工程师。The effect on Vincent of this firm and terrible rejection was devastating.这个坚定而糟糕的拒绝对于文森特的影响是毁灭性的。When Eugenie rejected him, Vincent did what many before him have done and will always do.当尤金拒绝他的时候, 文森特做了在自己面前总能做的许多事。He found religion.他用宗教给自己解脱。He didnt have to look very far.他看起来不是很远。It was aly there in his blood, his upbringing.这已经在他的血液中,在他的成长环境中形成。He started ing the Bible at nights, puffing away his pipe, coming home early from work.他开始在晚上阅读圣经,吸着烟斗,而且很早就下班回家。Hed go to Salvation Army meetings at Elephant and Castle,他还曾经去过大象城堡的救世军会议。hang around the soup kitchens and the prayer halls, sinking ever deeper into a melancholy love stupor.徘徊在厨房,祈祷大厅,因为爱情麻木带来的忧郁越陷越深。His work was now going so badly that his bosses decided to transfer him again to Paris.他的工作现表现如此之差以致于他的老板们决定把他再弄到巴黎。This is the old Goupil Headquarters in Paris where Vincent was made head of pictures.这是古旧的在巴黎的古皮尔总部,文森特在这里负责照片。注:听力文本来源于普特201207/190122

The acceptable face of FacebookFacebook中一个可亲的面孔Social skills for a social network一个社交网站所需的社交能力Few corporate types can charm hardened hacks so effectively.很少有商界人士能像Sheryl Sandberg似地懂得讨老油条似的媒体的欢心。Sheryl Sandberg, the number two at Facebook, the worlds biggest social network, has been glad-handing reporters with spectacular results. The New Yorker says she may “upend Silicon Valleys male-dominated culture”.身为最大社交网络—Facebook的二当家的谢勒尔 桑德格最近一直忙着亲切会见记者们。这些记者都对她赞不绝口:New York magazine puts her in line for Secretary of the Treasury.纽约客称她可能会改变木硅谷男性主导的风气,Bloomberg Businessweek speculates that she might one day be the president of the ed States.纽约周刊将她与财务部长相提并论,彭商业周刊推测她可能有一天会成为美国总统。Her sudden lionisation is well-timed.她的突然成名来的恰是时候。Facebook is expected to go public soon, perhaps this year.因为Facebook很可能会在本年很快上市。It may be the biggest internet flotation ever, with a market capitalisation of more than 0 billion.拥有超过一千亿的市值,届时可能成为迄今为止最大的上市互联网公司。Investors might be less bullish if the 27-year-old Mark Zuckerberg, the founder, were in sole charge. Many consider him somewhat socially awkward.而如果27岁地Facebook的创始人马克 扎克伯格独挑大梁的话,投资者可能不会这么看涨。因为很多人认为他有些欠缺社交能力。Ms Sandberg, a 42-year-old former Google executive, joined Facebook in 2008; without her, insiders say, it would not have grown from a cash-bleeding start-up to a titan with estimated sales of billion last year.现年43岁的前google经理人,Ms Sandberg,是在2008年加入脸书的。很多业内人士说,如果没有她,Facebook不可能会从一个亏损的新企业成长为一个去年预计销售额达20亿美元的巨人。She complements Mr Zuckerberg well.她和扎克伯格可谓是珠联璧合。He is technologically brilliant and knows it.他,技术精湛,而且其也心知肚明;She is a good listener with a keen financial brain.而她,作为一个优秀的倾听者,还兼备着敏锐的财务头脑。She provides adult supervision and a professional face to a firm growing so powerful and so quickly that it is bound to clash with governments.她为一个成长地如此有力且迅速的公司提供了成熟的监管和专业化的方向。Were Mr Zuckerberg to be grilled by senators who have not yet grasped the concept of e-mail, he might let his irritation show. Ms Sandberg would not have that problem.试想一下,如果让一群还没明白什么事电子邮件的参议员来拷问扎克伯格,扎克伯格可能会让他们看看什么是扎克伯格的愤怒。但是桑德伯格就不存在这样的问题。Since Carly Fiorina and Meg Whitman left HP and eBay, female bosses of big Silicon Valley firms have been rare.自从卡莉?费奥莉娜和梅格?惠特曼离开惠普和易趣之后,硅谷的大型公司的女性老板变得稀少了。而桑德伯格在尽量改变这种状况。Ms Sandberg is doing her part to change this by encouraging women to be more assertive and by building an “old girls network”.她建立了一个老女孩社区来鼓励妇女们变得更坚定而自信。Thanks to her efforts Facebook has more female executives than the average technology firm.多亏了她的努力,脸书比一般科技公司拥有更多的女性经理人。但是,很奇怪,她并不是董事会成员。Speculation about her future is inevitable.对她的未来进行预测是难免的。But for now she is unlikely to move.但是目前她不太可能跳槽。Facebook has far to go before it fulfils its founders mission to become the “social utility” of the online world and Google has launched a rival service.要实现它的创立者的梦想,即成为网络世界的社交公共设施。尤其是在google推出一个类似的务之后,Facebook还有很长的路要走。It may take a Google veteran to fight back.要想反击成功,一个熟悉google的老手必不可少。 点击此处下载本期经济学人讲解PDF与音频字幕 /201303/230163Don: Hey Yael, did you know that people with red hair need more anesthesia during surgery than other people?唐:嘿,雅艾尔,你知道吗,红发的人在做手术时需要注射比别人更多的麻醉剂?Yael: Oh, cmon Don, thats just another superstition about redheads—like redheads have hotter tempers. Back in the Middle Ages they used to think that people with red hair were witches.雅艾尔:啊,少来了,唐,这是人们对红发的又一个迷信——就像红发的人脾气更暴躁。在中世纪人们认为长有红发的人是巫师。Don: But Im not being superstitious. Dozens of studies have shown that it takes about twenty-percent more anesthesia to knock out redheads than it does people with other hair colors.唐:但这次不是迷信。几十项研究表明:相比其他发色的人,红发的人昏迷所使用的麻醉剂要多出20%。Yael: Why?雅艾尔:为什么?Don: Well, its all about pigment.唐:其实,这与色素有关。Yael: You mean the particles that determine the color of hair and skin?雅艾尔:你是指决定头发或皮肤颜色的粒子?Don: Right. So the amount of pigment you have is controlled by a hormone in the brain. Redheads have more of this hormone—and that matters because the pigment hormone is also involved with pain perception. So for some reason, because redheads have an abundance of this pigment hormone, theyre more sensitive to pain...唐:对。因为色素的数量由大脑中的荷尔蒙控制。红发人分泌更多这种荷尔蒙——这是关键的一点,因为色素荷尔蒙也涉及到痛知觉。因此出于某种原因,红发人体内含有更多的色素,因此对疼痛也更加敏感。Yael: ...which is why it takes more anesthesia to knock them out. So does this matter in any major way?雅艾尔:...这就是为什么需要更多麻醉剂才能使其迷昏的原因。那么对某些重要的方面有影响吗?Don: Well, I guess it does if youre a redhead. But its not like you have to be worried about waking up during surgery, screaming in pain. Surgeons and anesthesiologists are well aware of the phenomenon. Because, Yael, its science, not superstition.唐:好吧,我觉得如果你张着红发,就有影响。但不要担心会发生半路在手术台上醒来,痛得大叫这种情况。手术医师和麻醉师也充分了解这种情况。因为这是科学,不是迷信,雅艾尔。Yael: Touché.雅艾尔:言之有理。原文译文属!201210/203863

Thats crazy, sound.这是一种疯狂的声音。Space is adjustable.空间是可调节的。Its actually malleable. Space and time are malleable.它实际上是可塑的。空间和时间具有可塑性。This is flexible thing that can be twisted.它的灵活可以扭曲。You bring an object into space and it distorts the space around it.你把一个物体送入太空,它将会扭曲周围的空间。Why does the earth go around the sun?为什么地球环绕太阳?Most people would say, well, the suns gravity is yanking the earth toward the sun in a circle.大部分的人会说,好吧,太阳的引力将地球朝向太阳围成一个圈。Wrong! The earth is going around the sun because the sun has whirled the space around the earth.大错特错!地球绕着太阳转,是因为太阳围绕地球的空间旋转。And space is pushing, pushing the earth toward the sun. He had a new theory of gravity, a new theory of the universe.空间推动,推动地球向太阳。他有一个新的重力理论,一个新的宇宙理论。Einstein publishes his ideas about gravity.爱因斯坦发表了他对重力的观点。At the same time, his work on the atom brings him increased attention.与此同时,他在原子方面的著作也带给他注意力。As a result, in 1911, hes offered a position as a full time scientist at the university of Zurich.结果,在1911年,他在苏黎世大学被给予了一个全职科学家的位置。The 32-year-old patent clerk finally leaves Bern to become, for the first time, Professor Albert Einstein.这位32岁的专利局职员终于离开了伯尔尼,第一次成为阿尔伯特·爱因斯坦教授。注:听力文本来源于普特201203/176333Science and Technology Materials science Cracking a problem科技 材料科学 通过裂纹解决问题Another use for a fashionable, new material一种流行新材料的新用途LIKE all other human activities, science is subject to fads.像其它人类活动一样,科学是一个时尚主题。One of the latest is for graphene.最新的话题是关于石墨烯的。This wonder material—a form of carbon that comes in films a single atomic layer thick—won Andre Geim and Konstantin Novoselov the Nobel prize for physics last year.作为碳的一种形式,这种源自胶带操作的奇妙材料只有单原子层厚度,发明者安德烈·杰姆和克斯特亚·诺沃塞洛夫为此获得了去年的诺贝尔物理学奖。Because of its unusual electrical properties it has been touted as a way of making everything from touch screens to solar cells.由于石墨烯非同寻常的电特性,它被吹嘘为制造一切产品的新途径--从触摸屏到太阳能电池。Now a humbler use is being proposed.如今石墨烯的一种低层次应用被提出来。Another of graphenes qualities is that it is strong. That, suggests Erica Corral of the University of Arizona, makes it ideal for reinforcing ceramics.它的另一特性是机械强度高,因而被亚利桑那大学的埃里卡·科拉尔视为加强陶瓷材料硬度的一种理想材料。Engineers like ceramics because they can be heated without melting. Unlike metals and plastics, though, they are brittle.工程师喜欢陶瓷材料,因为它们加热时不会融化,这点不像金属和塑料,尽管它们是脆的。Because they crack easily, using them in places that are exposed to a lot of physical punishment is difficult.因为陶瓷材料易碎,因此将其用于高物理强度的场合非常困难。But a paper just published in the American Chemical Societys journal, Nano, by Dr Corral and her colleagues, suggests a sprinkling of graphene may deal with that.但在美国化学协会杂志刚发表的一篇论文《纳米》中,科拉尔士和她的同事们认为,加入少许石墨烯也许就能解决这个问题。The ceramic they experimented with was silicon nitride, a material much admired in the aerospace industry.她们测试的陶瓷材料是氮化硅--一种在太空工业中饱受赞誉的材料。Components are made by sintering it in powder form in a mould, at 1,000oC, for several hours.这些部件是将氮化硅粉末置于模具中,处于1000摄氏度高温下烧制数小时而成。Unfortunately, graphene disintegrates above 600oC, so the team had to think of a clever way of mixing the two materials.不幸的是,温度高于600摄氏度,石墨烯就碎裂,因此研究团队必须想出一种巧妙办法将两种材料融合在一起。Their solution was to take advantage of graphenes electrical conductivity, by running a current through the mixture. This generated a temperature of 1,650oC—more than enough to sinter the silicon nitride.解决办法就是利用石墨烯的导电特性,将电流通过混合物,产生的1650摄氏度的高温足以烧结氮化硅,而石墨烯也没有碎裂。The graphene, however, did not break down.其原理尚未完全弄清楚。Why, is not entirely clear. But rapid electrical heating did not seem to affect it in the way that slower oven heating would.但与通过熔炉缓慢加热不同,快速电加热对石墨烯看起来没有什么影响。The result was a composite that was able to withstand twice as much pressure as unalloyed silicon nitride.和纯氮化硅相比,其合成物能经受的压力强度翻倍。When the team examined what they had done under a microscope, they found that the graphene had wrapped itself around the silicon-nitride grains, forming continuous walls.当研究团队在显微镜下观察合成物时,他们发现石墨烯包裹在氮化硅颗粒周围,形成了连续的;壁;。When they looked at samples that they had whacked hard enough to come close to cracking, they found that these walls were encouraging the cracks to sp in three dimensions—in contrast with the two-dimensional pattern usually seen in silicon nitride.当检查这些不断敲击而近乎开裂的样品时,他们发现这些;壁;有助于裂纹向三个维度上延伸,和通常在氮化硅上观察到的;二维裂解模式;形成了对比。Dr Corral suspects that extending cracking into the third dimension dissipates the energy faster and stops the fault sping.科拉尔士推测,那种裂纹扩展为三个维度使能量扩散的更快,同时制止了缺陷的扩展。A cracking idea, as it were.通过三维裂纹来增强陶瓷材料强度,真是一个绝妙的点子! /201212/214745

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