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西安交通大学第一附属医院肠炎十二指肠溃疡十二指肠炎爱问中文

2019年07月19日 09:26:46|来源:国际在线|编辑:康泰新闻
Science and technology科学技术Solar-powered flight太阳能动力飞行Its moment in the sun日间时刻An attempt to fly around the world in a solar-powered plane尝试驾驶太阳能飞机环游世界A REVOLUTIONARY solar-powered aircraft touched down recently at Moffett Airfield, in the heart of Silicon Valley.一架革命性的太阳能飞机近日在硅谷中心的墨菲特联邦机场着陆。No champagne corks were popped, however, for it arrived disassembled in the belly of a 747 cargo jet.可却没有香槟酒庆贺,因为这是一架由波音747喷气式货机运输的解体飞机。The aircraft will be reassembled by the end of March and then begin flight tests.它会在三月底重新组装,继而进行飞行测试。If all goes well, by May it should be y to fly across America, stopping in four cities before landing in New York.万事顺利的话,它将在5月底横越美洲,途径四座城市,最终抵达纽约。However, this aircraft is just an experimental prototype for a much bigger exploit.然而,人们希望利用这架供以实验的原型机实现更加宏伟的目标。The team behind the project, called Solar Impulse, are using their prototype to learn what will be required to build a second aircraft capable of circumnavigating the globe using only the power of the sun.作为此次计划的执行团队—太阳驱动,通过研究该原型机,获得了一系列能使太阳能飞机实现环球飞行的参数。After carrying out a number of successful test flights of the prototype from their base at an airfield in Payerne, Switzerland, construction of their second aircraft began.团队成员在位于佩耶纳某一机场的总部对原型机进行了一系列成功的飞行测试后,便开始着手建造第二架太阳能飞机。But last July the Solar Impulse project suffered a big setback.但就在去年七月,太阳脉冲团队遭受了一个巨大的挫折。The second aircraft failed a critical safety check.第二架飞机的一项关键性安全检查不达标。Its main wing spar, the backbone of any aeroplane, broke during structural tests.在结构测试中,撑飞机的主翼梁发生了断裂。There is always a risk of pushing technology too far when doing something new.不切实际地尝试新技术总会留下隐患。Bertrand Piccard, one of Solar Impulses founders, had been in the same situation before and knew that success comes by learning from mistakes and moving on.太阳驱动的创始人之一—伯特兰·皮卡德也曾深陷此境,他深知技术的推进只能是吃一堑,长一智。In 1999 he co-piloted Orbiter 3, the first balloon to circumnavigate the globe.1999年,皮卡德曾担任轨道飞行器3号的副驾驶,这是第一个实现环球飞行的热气球。It was when he landed in the Egyptian desert with just 40kg of propane left from the 3.7 tonnes he had taken off with 20 days earlier that Mr Piccard decided his next challenge would be to repeat the flight using no fuel at all.在飞行了20天以后,气球在埃及的沙漠中着陆,此时原本携带的3.7吨丙烷就只剩下40千克,这激发了皮卡德向无燃料环球飞行发起挑战。He teamed up with Andre Borschberg, a fighter pilot and engineer, to form the Solar Impulse project.于是他与战斗机飞行员兼工程师—安德烈·尔施伯格通力合作,共同发起了太阳驱动计划。Mr Piccard comes from a line of adventurers.皮卡德来自探险之家。His grandfather, Auguste, was the first to fly a balloon into the stratosphere.他的祖父,奥古斯特,是驾驶气球飞入平流层的第一人。His father, Jacques, plunged to record depths in a deep-sea submersible.而他的父亲,雅克,专注于深海潜探,并创造了下潜深度的历史记录。Making the most of it万般皆有用The problem with the wing spar has set back the team a year.这个团队花费了一年时间来解决翼梁故障。Making a new one, completing the second aircraft and waiting for suitable weather means that the round-the-world flight is now scheduled for 2015.在实现环球飞行之前,他们必须制造一架新飞机,完成第二架飞机的组装,在适宜的天气下试航,所有这一切都要在2015年才能完成。In the meantime, the team decided to make the best of their enforced delay by flying their prototype across America.与此同时,尽管受客观条件制约,团队成员还是决定利用此次机会驾驶原型机飞跃美洲。This will provide more valuable operating experience and help with the development of the technologies they will need.此举不仅能提供更多弥足珍贵的操作经验,还能推动所需技术的改良。Plus, if anything goes wrong, it is easier to land on dry land than the ocean.再者说,如果飞行遭遇意外,陆地着降总要比海面着降轻松许多。Solar-powered aircraft are not new.太阳能飞机由来已久。One of the earliest, Solar Challenger, flew across the English Channel in 1981.早在1981年,太阳挑战号就成功飞越英吉利海峡。It was built by the late Paul MacCy, an American aeronautical engineer.这架飞机由已故美国航空工程师保罗?麦卡克莱迪建造。Its 14.3-metre wing was covered in photovoltaic cells.其14.3米长的机翼上布满了光生伏打电池。These powered two electric motors, which in turn drove a single propeller.推动唯一螺旋桨发动的两台电动机正是由这些电池供电。The Solar Impulse project is a very different beast.然而太阳驱动计划却开辟了一片新天地。The prototype aircraft which will fly across America has a wingspan of 63.4 metres, which is as big as a jumbo jets.飞越美国的原型机翼展宽达63.4米,与巨型喷气式飞机同宽。Yet its fuselage is as slender as a gliders and its single-person cockpit is cramped.而其机身却与滑翔机一般大小,窄小的驾驶舱只能容下一名飞行员。The wings are covered in almost 12,000 photovoltaic cells, which can simultaneously run its four electrically driven propellers while charging four packs of lithium-polymer batteries.机翼覆盖着12000块光生伏打电池,在为四组锂聚合物电池充电的同时,还能一同撑四个电驱动螺旋桨运转。The batteries are needed because the aircraft has to be able to fly through the night.之所以携带电池,是因为飞机需要在晚间飞行。The second aircraft will have to do that non-stop for five-to-six days at a time.第二架在建的环球航行飞机需实现一连5、6天不间断飞行。The plan is to take off in an easterly direction and land on every continent that touches the Tropic of Cancer.飞机将于东部地区起飞,随后在北回归线附近的每一块陆地降落。This will involve long flights across oceans.期间包括漫漫的洋面飞行。With only as much power as a motor scooter, the planned aircraft will cruise at just 70kph.按计划飞行动力与小型托车一般,因而只能以70km/h的速度匀速行驶。Its ultimate range will be limited by the physical ability of the pilot to remain alert, with little room to move or to store much food and water.狭小的机内空间,加之有限的食物与饮用水,飞机的最大航行距离就完全取决于飞行员自身的身体素质。With current technology, the team reckon, a two-person solar plane would be too heavy.团队成员认为,以目前的技术,双驾驶太阳能飞机负重过大。To give Mr Piccard and Mr Borschberg room to exercise and lie down, the next aircraft will be about 15% bigger than the prototype, which tips the scales at just 1,600kg.为了给皮卡德和尔施伯格足够的空间移动和躺卧,新的飞机将比原型机大15%,总重达1600千克。Weight is the critical factor.重量是关键性问题。The wing spar that broke had been redesigned with an ultralight carbon-fibre process to shed the grams.先前破损的翼梁用超轻型碳纤维材料重新打造以降低克重。But we went too close to the limits, confesses Mr Borschberg.尔施伯格不得不承认,这已是我们所能之极限。There is little scope for a full autopilot system, and it would weigh too much.完整的自动驾驶系统会使飞机不堪重负。However, Altran, an engineering consultancy based in France and one of the projects supporters, is developing a partial system.不过项目持商之一的法国Altran工程咨询公司,部分解决了自动驾驶问题。In calm weather, it will keep the aircraft pointing in the right direction.风和日丽之时,这套系统会帮助飞机沿着正确的方向前行。And if turbulence causes a wing to dip by more than five degrees, a cuff on the pilots right or left arm will vibrate to tell him which way to correct course.如若飞机机翼受气流影响下沉角度超过5度,它就会通过振动驾驶员某一膀臂上的袖带来指引正确的行驶方向。He must react quickly to keep control.驾驶员的反应速度决定着飞机平稳与否。This system will be tried out on the prototype flight in America.这套系统将在横越美洲的原型机上试用。The ground crew can monitor both the flight and the pilot with telemetry.地勤人员可以通过遥测装置对飞机和飞行员进行监控。When circumnavigating the globe the pilot will be able to lower a seat to lie down and take catnaps of up to 20 minutes.在环球飞行时,飞行员可以将座位调低,这样便可以躺在上面小憩20多分钟。That is enough, the team calculate, to ward off some of the effects of sleep deprivation.团队成员通过计算认为这些时间足够抵御睡眠不足带来的不利影响。The pilot must not be too groggy if he has to swing suddenly into action.当飞行员突然驾驶时,他一定不可以过于疲劳。This procedure has been tested in a flight simulator for 72 hours non-stop, and seems to work.这套流程已在模拟飞行器中进行了72小时不间断测试,效果卓著。A typical flight involves taking off in the early morning, when winds are light, and ascending to 10,000 metres to stay above any stormclouds.普通的飞行包括在风速平稳的清晨起飞,随后上升至10000米的高空以躲避暴风云层。At this altitude, though, the air is thin and an oxygen supply is needed.由于海拔较高,空气稀薄,必须提供足够的氧气。The pilot has to wear an oxygen mask because pressurising the cockpit, as an airliner does with air from its jet engines, is not possible.飞行员只得佩戴氧气罩,因为太阳能飞机无法像普通大型客机那样利用喷气引擎的气流保持驾驶舱的气压平稳。Nor do the team want to carry heavy oxygen cylinders.氧气瓶也因为过于沉重而不切实际。As an alternative Air Liquide, an industrial-gases firm, is developing a solar-powered system to generate oxygen.与法国液化空气公司类似的一家工业用气公司正在研制如何利用太阳能产生氧气。At night the pilot descends slowly, carefully using up the power until dawn.夜晚时,飞机缓缓下降,在黎明前用尽所有燃料。Once the sun returns the batteries can recharge in three hours as the plane ascends again.当太阳升起时,电池会在三个小时内充满,然后飞机便再次起飞。Landings are also left until the early evening, when winds are light.同起飞一样,降落也挑选在风速平稳的傍晚。The flight across America will give the teams meteorologists an opportunity to see how their weather models stand up.飞越美洲的航行也可以验团队中气象学家的天气模型是否成立。Sometimes it is necessary for the pilot to delay a landing to wait for optimum conditions.有时,飞行员必须延迟降落时间以寻求最佳时机。Mr Piccard and Mr Borschberg have learned an interesting technique to do that.皮卡德和尔施伯格用一种有趣的方式进行观察。Flying slowly, they turn the nose into a headwind, which can make the aircraft fly backwards.他们会逆风缓慢飞行,这样飞机就会受气流影响向后移动。It is not the sort of thing to try in a jumbo jet.而这在巨型喷气式飞机上是不可想象的。 /201309/258577Don: Hi everyone. On this show we usually talk about other peoples experiments, but today were going to do an experiment of our own. Heres the deal: see if you can tell if Im smiling or not as I speak. Ready? Heres goes. Am I smiling now? How about now? What about...唐:嗨,大家好。这个节目一般讲其他人的实验,但这一期我们可以拿自己做实验。具体情况是这样的:猜猜看,我是在笑呢,还是没有笑。真的吗?现在开始。我在笑吗?现在呢?...怎么样?Yael: Wait, hold on. Don, what are you doing?雅艾尔:等等,打住。唐,你在干什么?Don: An experiment. Like I said, I want to see if our listeners can tell if Im smiling just by the sound of my voice.唐:做实验。正如我说的,我想知道听众是否能通过我的声音分辨出我在微笑。Yael: But how is that possible?雅艾尔:但这怎么可能呢?Don: Researchers at the University of Portsmouth, in England, have worked on this. They recorded interviews with volunteers who were asked silly questions, the idea being to make them smile as they spoke. Then the researchers played the recordings for another set of volunteers and asked them to identify when the speakers were smiling. And more often than not, they could.唐:英国朴茨茅斯大学的研究人员正在研究这个。他们问志愿者很傻的问题,让他们在回答的时候感到好笑,并记录了采访过程。然后研究人员向另一组志愿者播放采访录音,让他们分辨说话人什么时候在笑。而且大部分时候都能猜对。Yael: Interesting. Is that because smiling affects the vocal cords or something?雅艾尔:真有趣。那是因为笑会影响声带还是什么吗?Don: Sorta. Its probably more that smiling can affect your pitch, making your voice sound higher. So the listeners might have been picking up on that cue. They might also have been concentrating on the intensity of the voices. Its not an exact science, obviously, but something was tipping off the listeners.唐:差不多。微笑更有可能影响你的音高,让声音听起来更高。因此,听者可能是根据这条线索来做出判断。他们也许一直专注于声音的强度。显然这不是一门精密的科学,但听的人的确可以发现点什么。Yael: So does this have any practical application?雅艾尔:那这个研究有没有什么实际用途呢?Don: It could help improve voice recognition software and synthetic voices for things like computer games.唐:它对声音识别软件的开发很有帮助,还有电脑游戏中的那些合成声音。Yael: Cool. OK, so let me try. Im smiling now, can you tell? And now Im not smiling. Do I sound different?雅艾尔:酷。好吧,让我试试吧。我现在在笑,你能分辨出来吗?现在我没有笑了,我的声音听起来有什么不同吗?Don: Yes...and yes. 唐:是的...是的。原文译文属!201305/238934

Science and technology科学技术Animal behaviour动物行为Cold-blooded cunning狡猾的冷血动物Reptiles are more intelligent than previously thought爬行动物的智商比人们之前想象的要高IT IS no compliment to call someone lizard-brained.如果某人被称为蜥蜴脑,那可不是什么恭维的说话。The reptilian mind is usually equated in the human one with traits like aggression, dominance and sexual appetite.爬行动物的头脑通常情况下与人脑相同,也具有侵略、配和性欲的特性。That analysis was given currency in the 1960s when Paul MacLean theorised that the human brain has three levels,这种分析在20世纪60年代得到流行,当时保罗?麦克莱恩从理论上推断人脑具有三个层次,the most basic—both functionally and literally—being the “reptilian” part, composed of structures called basal ganglia.人脑最基本的层次—从功能和字面上理解与;爬行;动物相同,它由基底神经节结构组成。MacLeans analysis is not much believed now by neuroscientists,麦克莱恩的分析并不为现在的神经学家所认同,but it has stuck in the popular imagination.但它始终存在于大众的意识中,And it has also, subliminally, affected research.并一直对科学研究有着潜在的影响。For, until recently, no one had actually thought to ask by experimentation just how intelligent reptiles really are.直到最近,人们都没有真正想过要通过实验测得爬行动物的智商到底如何。That omission has just been corrected by Manuel Leal and Brian Powell of Duke University, in North Carolina—and the result is intriguing.北卡罗莱纳州杜克大学的Manuel Leal和Brian Powell对这一疏忽进行了纠正—其研究结果激发了人们浓厚的兴趣。In a paper published in Biology Letters Dr Leal and Dr Powell suggest that lizards are at least as intelligent as tits, a group of birds that has been well examined in this respect.Leal士和Powell士发表在生物学快报上的论文表明蜥蜴的智商绝对不比山雀低,研究人员在此方面曾对这组鸟类有过很好的研究。In their study, the two researchers put a species called Anolis evermanni through a triathlon of cognitive tests of the sort used on tits.在他们的实验中,两名研究人员让一个叫热带树蜥的动物成功通过一个三项全能的认知测试,这种实验曾用于山雀。First, the reptiles had to learn how to extract a tasty grub from a container.首先,爬行动物必须学会如何从容器中获取甜美的食物。Then, they were taught to associate the grub with a particular colour.然后教它们如何将食物与一种特定颜色相关联。Finally, they were taught to dissociate it from that colour and learn that a different colour was the giveaway.最后教它们将食物与那种颜色脱离联系并学会一种不同颜色代表的是免费美食。The lizards were able to manage all three tasks with ease—matching the performance of tits in similar tests.蜥蜴能轻松地完成三项任务—在相同测试中与山雀的表现不分伯仲。Indeed, in getting at the grubs several of them worked out a form of behaviour never seen in nature,实际上,在获取食物之时,有几只蜥蜴表现出的行为方式是在自然界中没出现过的,employing their snouts as levers to lift an obstacle.它们用鼻子作为手段将障碍物移走。Having established that lizards are at least as clever as birds at such simple tasks, Dr Leal hopes to go on and explore the evolutionary forces behind lizard intelligence.在确定了蜥蜴完成简单任务时至少和鸟类同等聪明之后,Leal士希望将实验进行下去并探索蜥蜴智力背后的进化力量。He does, however, have a problem—and it is one that might help to explain why, besides phylogenetic prejudice, the lizard mind has not been properly investigated before.而他的确有一个疑问,这个疑问也许对解释以下问题有所裨益,那就是除去对物种的偏见之外,还有什么原因使得人们之前未展开适当的研究来测定爬行动物的智商。Tits, being warm-blooded, have to eat a lot and thus have a strong incentive to collaborate with researchers in such experiments.山雀属于温血动物,它必须吃大量的食物以维持身体的能量,这就使它们具有强烈的动机与研究人员配合进行这种实验。The average lizard, by contrast, is happy to consume a single grub a day.相比之下,平均每只蜥蜴一天中只乐意享受一次美食。It may therefore be some time before the next paper appears on the subject.因此,下一篇与此主题相关的论文可能需要很长时间才能发表。 /201305/238284

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