时间:2019年12月12日 17:22:52

Science and technology.科技。Photoelectric cells.光电池。To dye for.利用染料进行能量转化。A new type of cell may bring ;solar; energy indoors.一种新型电池也许能带来室内;太阳能;。THE phrase ;indoor solar power; sounds like an oxymoron. But there is growing interest in the idea of using photoelectric cells to run gadgets as well as power grids-and doing so even when those gadgets are inside buildings. Much of the light these cells used would, of necessity, come from incandescent bulbs, fluorescent tubes and light-emitting diodes (LEDs) rather than through the window from the sun. But if the right sorts of cells were available this could be cheaper than constantly replacing the batteries that currently power electronic gizmos.;室内太阳能;这个词听起来有点儿自相矛盾,可科学家们对于利用光电池来驱动用电装置和电网越来越感兴趣了—这些光电池即使在室内也能够正常工作。它们所利用的光能中的大部分势必来自白炽灯,日光灯和发光二极管,而并非透过窗户照射进来的太阳光。不过一旦某种特殊的光电池被研发出来,相比于通过频繁更换电池为用电装置供电的传统方式,新型光电池的应用将能够大大降低成本。On April 8th G24 Innovations, a firm based in Wales, announced that it may have come up with just such a cell. The latest version of its special, dye-based photoelectric devices has set a new record for the conversion of light from bulbs into electricity: an efficiency of 26%, compared with the 15% which previous ones can manage. That lifts dye-based cells to the point where they might be widely deployable for indoor power.在四月八日,一个总部位于威尔士的公司——G24 Innovations宣布他们已经开发出这种光电池。它的独特之处在于其基于染料的光电转化设置,该装置最新版本的转化效率已经从上一代的15%提高到创纪录的26%。这大大增加了将该类型电池应用于室内供电领域的可能性。Dye-based cells are similar to the silicon-based variety found on rooftops around the world in that both rely on a semiconductor to assist the conversion of luminous energy into the electrical sort. The difference is that in the case of silicon cells, this conversion happens directly. That means the frequency of light absorbed is constrained by the physical properties of silicon itself.这种基于染料的光电池同另外一种基于硅的光电池——如今已在全世界广泛应用,与屋顶随处可见——比较相似,它们的光电转换都依赖于一种半导体。不同之处在于硅型光电池的光电转化过程是直接进行的。这意味着被吸收的光的频率将受限于硅自身的物理性质。In the case of dye-based cells, which were invented at the Federal Polytechnic School of Lausanne, in Switzerland, in the 1990s, the light is first captured by molecules of a photosensitive dye. Tinker with the composition of this dye and you change the frequency of light that can be captured. This makes dye-based cells more flexible than silicon ones.至于染料型光电池,它们在二十世纪九十年代发明于瑞士洛桑的联合工艺培训学校,是利用光敏染料分子将光捕获。若要捕获不同频率的光,只需对染料的成分进行调整。因此染料型光电池使用起来比硅型光电池更为灵活方便。The dye molecules themselves are bound to tiny particles of titanium dioxide, a less-famous (but cheaper) semiconductor than silicon, and the whole assembly is immersed in an electrolyte and sandwiched between two electrodes. When a photon of light is absorbed by a dye molecule, an electron is knocked into the titanium dioxide. From there it travels to one of the electrodes and a current is thus generated.染料分子自身会与二氧化钛(一种不如硅名气大,但比硅便宜的半导体)的细小微粒相结合,然后整个装置会浸没于一种电解质里并夹于两个电极之间。当一个光子被一个染料分子所吸收,就会有一个电子被击入二氧化钛,这些电子会从二氧化钛中流入其中一个电极,从而产生了电流。The flexibility brought by the dye-based approach makes this sort of cell particularly useful indoors. Silicon-based solar cells have been optimised for sunlight. But artificial light, whether of the incandescent, fluorescent or LED variety, contains a different mixture of frequencies from that put out by the sun. By changing the composition of the dye, G24s engineers ensure that the maximum sensitivity of the cell coincides with whatever frequency mix is appropriate for the artificial light concerned.染料型光电池的这种灵便性使其能在室内发挥很大作用。硅型光电池是面向于太阳光的,而对于各种人造光源,无论是白炽灯,日光灯还是LED灯,它们发出的光的混合了多种频率,且与太阳光的不同。(为了利用人造光源的光能,)G24的工程师们通过改变染料的成分确保光电池的最大灵敏度区域契合于人造光源所发出的光的混合频率。Besides being tweakable to match the spectrum of a light-bulb, dye-based cells also work well in dim or diffuse light of the sort often found indoors. Silicon-based systems do not. And dye-based cells, having no rigid parts, can bend, and are mechanically robust compared with the silicon sort. That gives them a further advantage over silicon cells, especially for powering consumer gadgets.除了能根据灯泡光的光谱对吸光性能进行微调外,即使是在常见于室内的昏暗或漫射的光照情况下,染料型光电池也能够正常工作。这个优点是硅型光电池所不具备的。而且染料型光电池全由非刚性材料构成,可弯可折,与硅型光电池相比其机械强度更高。这使得它们比硅型光电池又多了一项优势,尤其是在消费电子类产品供电领域。Steven Burt, G24s chief financial officer, talks of light-bulb-powered TV remote controls, smoke detectors and computer keyboards. (A non-removable internal battery would store charge for use when the lights are off.) The company aly offers prototypes of bags and jackets with photosensitive panels woven in, designed to charge digital cameras and mobile phones, and a hotel in Las Vegas is using G24s products to run its electric window-blinds. Mr Burt also sees a market for powering the networks of sensors needed to monitor things like temperature and humidity in modern ;smart; buildings.G24的财务总监——Steve Burt谈到可用灯泡光进行供电的有电视遥控器,烟雾检测器和电脑键盘(无灯光时其内置的电池会发挥作用)。这家公司已经开始提供袋子和夹克的样品,其中被缝入了光敏夹板,按照设计理念将可为数码相机和手机充电,此外一家的酒店正在使用G24的产品来运行其电动窗帘。而在另一片市场——智能建筑中构成监测网络的温度,湿度等传感器供电领域中,Burt同样看到了公司产品不错的应用前景。Eventually, says Mr Burt, the ability of dye-based cells to produce useful quantities of power even in dim and diffuse light could see them used outside, perhaps on rooftops in cloudier parts of the world-a market at present dominated by traditional, silicon-based cells, even though they are not well-suited to the purpose. But for now, G24s factory in Cardiff, not a city known for its sunshine, remains powered by a wind turbine.染料型光电池在昏暗光或漫射光的照射条件下依然能够产生数量可观的电能,Burt先生认为这项能力将会促使其在室外的推广应用,也许可以安装在多云天气区域的建筑物屋顶上(目前这片市场中占统治地位的还是传统的硅型光电池,虽然效果并不太突出)。不过直到现在,G24设在加的夫(这可不是一个阳光充足的城市)的工厂仍是由风力发电机供电。 /201209/198875

Books and Arts;Book review;The second world war;文艺;书评;第二次世界大战;Counting the cost;二战代价几何?Two British historians analyse the 20th century’s worst conflict.看两位英国历史学家如何剖析20世纪最严重的军事冲突。All Hell Let Loose: The World at War 1939-1945. By Max Hastings.《人间地狱:1939-1945,战争中的世界》 作者:马克斯·哈斯丁.The Second World War. By Antony Beevor.《第二次世界大战》作者:安东尼·比弗。 History is full of wars that were bloodier than the second world war. As a proportion of the population, more people were killed during the An Lushan rebellion in eighth-century China, for example, or by the Thirty Years War in 17th-century central Europe. But the sheer magnitude of the human tragedy of the second world war puts it in a class of its own, and its relative closeness to the present day makes claims on the collective memory that more remote horrors cannot.纵观人类历史,比第二次世界大战更血腥的战争比比皆是。例如,8世纪中国的安禄山叛乱或17世纪中欧的三十年战争死亡人数占总人口的比例就比二战大。然而,第二次世界大战造成的巨大人间惨剧本身让其他战争根本不能与之相提并论。而且,二战发生的年代相对较近,它给人类留下的集体记忆之深,是那些年代久远的恐怖战争无可比拟的。The statistics of the war are almost mind-numbing. Estimates differ, but up to 70m people died as a direct consequence of the fighting between 1939 and 1945, about two-thirds of them non-combatants, making it in absolute terms the deadliest conflict ever. Nearly one in ten Germans died and 30% of their army. About 15m Chinese perished and 27m Soviets. Squeezed between two totalitarian neighbours, Poland lost 16% of its population, about half of them Jews who were part of Hitler’s final solution. On average, nearly 30,000 people were being killed every day.有关二战的统计数据几乎让人麻木。各方估计的死亡人数有出入,但在1939-1945年的这场战争中,直接死亡人数高达七千万,其中三分之二是非战斗死亡,这使二战成为人类历史上绝对死亡人数最多的战争。二战时期,每十个德国人中就有一个死亡,德军死亡率达30%;约有一千五百万中国人和两千七百万俄国人丧命。夹在两个极权主义国家之间的波兰人口减少了16%,其中约一半是犹太人,那是希特勒的“最终方案”要解决的部分目标。当时,每天平均有将近三万人死于非命。Partly because it is so hard to grasp what these numbers mean, recent historians have tended to concentrate on particular theatres or aspects of the war with an emphasis on trying to describe what it was like for the human beings caught up in it. Both Antony Beevor and Max Hastings are distinguished exemplars of this approach. Mr Hastings has written books on Britain’s strategic bombing campaign, the Allied invasion of Normandy and the battles for Germany and Japan in the closing stages of the war. With several books aly under his belt, Mr Beevor became known in 1998 for his epic account of the siege of Stalingrad, and went on to produce accounts of D-Day and the fall of Berlin. Now both writers have tried something different: single-volume narrative histories of the entire war. In doing so, they are following in the footsteps of Andrew Roberts and Michael Burleigh, who made similar attempts in, respectively, and 2010.在一定程度上,人们很难明白这些数字意味着什么,所以最近的历史学家往往特别关注二战的某些战区或层面,致力于将亲身经历二战的人眼中的二战呈现给读者。安东尼#8226;比弗(Antony Beevor)和马克斯#8226;哈斯丁(Max Hastings)都是这方面的典范。马克斯#8226;哈斯丁已著有多本作品,内容涉及英国的战略轰炸、盟军的诺曼底联合登陆以及战争末期德日两国的战役。安东尼#8226;比弗同样也写了几本书。1998年,他笔下的围攻斯大林格勒令人印象深刻,他也因此闻名于世,之后他又写了关于诺曼底登陆日及攻克柏林的书。现在两位作家尝试了不同的写作方式,即跟随安德卤#8226;罗伯特(Andrew Roberts)和迈克#8226;伯利(Michael Burleigh)的脚步:以单卷本的方式讲述整个二战史。这两位作家分别在年和2010年尝试用单卷本写二战史。Mr Hastings got there before Mr Beevor. “All Hell Let Loose” was published seven months ago (it is now out in paperback) to justifiably rave reviews.马克斯#8226;哈斯丁的动作比安东尼#8226;比弗快。七个月前,《人间地狱》一书出版(现在出了平装本),理所当然地引起了人们的热议。201207/189503

Science and Technolgy.科技。The settlement of Madagascar.定居马达加斯加。Thirty lost souls.三十个迷失的灵魂。How Africas largest island was colonised by Asians.解读非洲第一大岛成为亚洲人殖民地的历史。MADASCAR is renowned for its unusual animals, particularly its lemurs, a group of primates extinct elsewhere on the planet. Its human population, though, is equally unusual. The island was one of the last places on Earth to be settled, receiving its earliest migrants in the middle of the first millennium AD. Moreover, despite Madagascars proximity to Africa (400km, or 250 miles, at the closest point) those settlers have long been suspected of having arrived from the Malay Archipelago-modern Indonesia-more than 6,000km away.马达加斯加岛因岛上的稀有动物而闻名,尤其是世界其他地方已绝迹的灵长类动物——狐猴。人类在该岛定居的历史,也同样不寻常。该岛是最后几个人类选择的定居地之一,于公元后头一个千年的中叶迎来了最早一批到此定居的移民。此外,尽管马达加斯加岛毗邻非洲大陆(最近距离400公里,合250英里),长久以来外界猜测岛上的居民是从马来群岛,即现在的印度尼西亚,这个6000多公里外的地方迁移来的。There are three reasons for this suspicion. First, it has been recognised for centuries that the Malagasy language, though distinct, borrows a lot of words from Javanese, Malay and the tongues of Borneo and Sulawesi. Second, the islanders culture includes artefacts ranging from boats with outriggers to xylophones, and crops such as bananas and rice, that are (or, rather, were then) characteristically Asian, not African. And third, genetic evidence has linked the modern Malagasy with people living in eastern Indonesia as well as farther off in Melanesia and Oceania.作此猜测原因有三。首先,存在了几个世纪的一种看法认为,该岛使用的马尔加什语,虽然独特,但很多的词汇是来自爪哇语、马来语和一部分口语来自婆罗洲及苏拉威西岛当地方言。其次,该岛居民的文化——包括从装有舷外浮木的小船到木琴等一系列手工制品,还有一些农作物,如香蕉和大米——都是(也可以说或多或少是、那时候是)具有亚洲特点的,而不是非洲。再次,基因学据已明现代的马达加斯加人与东印尼人以及相距更遥远的美拉尼西亚人和生活在大洋洲的人都是有联系的。Now, Murray Cox of Massey University in New Zealand and his colleagues have put the matter beyond doubt by showing not only where the first settlers came from, but also how many of them there were. And the answer is surprisingly few. Though Dr Cox is unable, with the method he used, to work out how many men were in the original party, the number of women was 30.现在,新西兰梅西大学的Murray Cox和他的同事们不仅科学地展示了首批定居者源自哪里,而且还弄清了定居者的人数,据确凿。让人感到吃惊的是已确定的定居者人数极少。虽然Cox士使用的方法没能弄清首批定居者中的男性数量,但可以确定女性有30人。He drew this conclusion, just published in the Proceedings of the Royal Society, by sampling the DNA of 266 Malagasy people and comparing it with existing samples from 2,745 Indonesians. He concentrated on DNA from mitochondria. These are cellular components involved in energy production that are descended from bacteria which became symbiotic with humanitys ancestors almost 2 billion years ago, and thus have their own genes. People inherit mitochondria only from their mothers, which is why only the female line of descent can be tracked using them.Cox士最近在学术期刊《皇家学会进展》(Proceedings of the Royal Society )发表的文章中对266名马达加斯加人进行DNA抽样,同现有的2745名印尼人的DNA样品进行了比对,得出了以上结论。他把重点放在对线粒体DNA的研究上。线粒体DNA是一种参与生物体能量制造过程的细胞器,起源于20亿年前与人类祖先共生的细菌,因而线粒体有自己的基因。人类仅能从母亲身上遗传线粒体DNA(线粒体DNA是严格的母系遗传),所以只有母系血统能使用追踪线粒体DNA的方法。The advantage of studying mitochondrial DNA is that it is not shuffled around by sex. Dr Cox and his colleagues were therefore able to make a statistical comparison of Indonesian and Malagasy mitochondrial genomes knowing that any changes which had occurred since they separated would be the result of rare mutations. These can be spotted and accounted for. Indeed, because they can be tracked they add to the information which can be extracted from a sample.研究线粒体DNA的优点在于它不会被性别打乱。Cox士和他的同事们因此能进行印尼人和马达加斯加人线粒体基因组的数据比对,从而推断出原本相同的线粒体DNA天各一方后发生的任何遗传变化都是源于一些罕见的基因突变。这些都是可以辨认及作出解释的,因为科学家可以追踪线粒体DNA上附加的信息,而这些信息可以从线粒体DNA样品中提取。Having confirmed that Malagasy and Indonesian DNA separated about 1,200 years ago, which is statistically close to the date archaeologists suggest Madagascar was colonised, the team then asked their data how many women, drawn at random from the Malay Archipelago of that period, would have been needed to explain the variation in mitochondrial DNA in Madagascar. The answer was about 30.由于已确定马达加斯加人和印尼人的DNA是在约1200年前分开的——这与考古学家们统计得出的马达加斯加成为殖民地的时间相近,接着Cox士带领的小组就开始对随机抽取的那一时期的数据进行女性人数的,看需要达到多少人才可以解释线粒体DNA在马达加斯加岛产生的变异情况。最后得出的女性人数为30人。That answer bears on a second question: was the colonisation of Madagascar a deliberate act or an accident? The first is possible. At the time, much of the Malay Archipelago was in the hands of the Srivijayan empire, an entity that could certainly have sent expeditions across the Indian Ocean, had it so willed. But there is no historical evidence that it did. In any case if it had, it is likely that a successful colonisation by one group would have been followed by others, as happened when Europeans discovered the Americas.由此又产生了第二个疑问:在马达加斯加进行的殖民活动是蓄意而为还是偶然而为?前者是有可能的。那一时期,马来群岛中的大多数岛屿都被一个名为Srivijayan的帝国所掌控。该帝国只要愿意,就完全有可能派出远征队穿越印度洋。但还没有史学依据明他们派出了远征队。不管怎样,如果他们真的这么做了,那么第一批人殖民成功,就会有其他人紧随其后,正如欧洲人发现了美洲大陆后的情况一样。Most likely, then, the first Malagasy were accidental castaways, news of whose adventure never made it back home. But there is still a puzzle. Most ships crews are male. Though the number of men in the original party will remain obscure until an analysis like Dr Coxs is done on the Y-chromosome of Malagasy men (Y-chromosomes include DNA passed exclusively down the male line in the way that mitochondrial DNA is passed down the female line), the presence of women on board a trading vessel would have been unusual. Unless, of course, the women themselves were the objects being traded. Possibly, then, Madagascar was colonised by an errant slave ship. Which would make its history even stranger than anyone had previously thought.那么,首批马达加斯加人也很可能是因船只失事而意外漂流到该岛的,而这批人后来也没办法回到家乡。可是这种说法仍然让人困惑,因为大多数的船员由男性担任,虽然在对马达加斯加人男性的Y染色体进行数据分析之前(包含DNA的Y染色体单传男系,同样的,线粒体DNA单传女系),例如Cox士的小组所作的工作,该岛首批居民的男性人数尚未明晰,那一时期在一艘贸易货船上出现女性是很罕见的事情。当然,例外情况是,女性本身就是贸易品。那马达加斯加岛就可能是一艘迷途的奴隶商船的殖民地了。这样一来,这段历史就会比先前任何人所想的更加奇特。 /201209/201215

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