天涯部落

小圈子,大声音!呼朋引伴网聚部落!

创建新部落?

襄阳市襄州区人民医院医院男科120报

楼主:时空大夫 时间:2019年07月24日 15:23:23 点击:0 回复:0
脱水模式给他打赏只看楼主阅读设置
Science and Technology Materials science Stronger when stricken科技 材料科学 越敲越结实A new material that gets stiffer when it is stressed一种受外力时硬度提高的新材料ONE of the valuable properties of bone is that when it endures repeated stress it responds by becoming denser and stronger.骨头有一种很珍贵的属性,那就是当受到反复的击打时,其质地反而会变得更加紧密,坚硬度变得更高。A living material can do that. A non-living one cannot.只有活性材料具备这种特征,非活性材料则不具备。It has no way of adding the extra matter needed to provide the extra density. But it would help engineers a lot if non-living stuff could at least stiffen in response to stress—and that may now be possible.用添加必要物质来让材料获得更高密度的方法是不可行的,但如果非活性材料起码可以在外力作用下变得坚硬—目前达到这一点是可能的,那么这对工程师们来说有非常大的借鉴意义。Brent Carey, a graduate student at Rice University in Texas, thinks he has found a way to make it happen.布伦特凯利是一名德州莱斯大学的研究生,他认为他已找到了实现这一设想的办法。Mr Carey made his discovery when he was testing the properties of a material made of carbon nanotubes (cylinders of carbon atoms a few billionths of a metre across) and a rubbery polymer called polydimethylsiloxane.凯利在测试一种材料的属性时有所发现,该材料的成分包含碳纳米管(直径为几纳米的碳原子圆柱体)和一种名为聚二甲基硅氧烷的橡胶聚合物。He created this composite by growing a forest of nanotubes using hot hydrocarbon gases and an iron catalyst, and then filling the space between the tubes with the polymer.材料的合成过程是这样:首先,他使高温碳氢混合气体和铁催化剂相互作用产生密集的碳纳米管群,然后再用聚合物充填碳纳米管间的空隙。The surprise came when he discovered how his new material responded to repeated stress.当他注意到新材料受到连续作用力而产生反应时,令他惊讶的现象出现了。He found this did not cause any of the damaging fatigue that would be expected.据他观察,预期中的材料损毁性疲劳并未产生。Indeed, his initial inspection suggested the stuff was actually growing stiffer.实际上,他的初步监测显示材料变得更加坚硬了。Fascinated by this result, he took his finding to his supervisor, Pulickel Ajayan, and they assembled a team to study the new material.这个结果让凯利喜出望外,他马上找到了自己的导师普里克尔阿贾扬,随后他们成立了一个小组,专门研究这种新型材料。They gave the composite a real workout. They compressed it five times a second for a week. That caused its stiffness to increase by 12%.他们给这种合成材料做了次实验:对该材料施加5.5倍的压力,时间持续一周,结果材料硬度提高了12%,Moreover, the effect showed no sign of abating,并且这种状态没有减弱的迹象。which led them to suspect that if it were exposed to more stress it would grow stiffer still.研究小组由此设想,如果对其施以更大的作用力,这种材料的硬度是否会变得更高。Why this happens is still a mystery.产生这种效果的原因还是个谜。Mr Carey and his colleagues report in the American Chemical Societys journal Nano that heating the new material did not eliminate the response.凯利和他的同事们发表在美国化工科学院的期刊杂志《Nano》的文章中说,即使对这种新型材料加热,也不能消除已产生的变化。This suggests that the self-stiffening is not the result of chemical changes in the polymer, which can usually be undone by heat.这说明材料强度提高并不是聚合物发生化学反应造成的,一般这种变化在加热状态下是可逆的。The researchers do have one lead, though. Because of the regular alignment of the nanotubes, they were able to stress the material from various directions.不过研究人员已有所发现。由于碳纳米管呈规律状排列,他们能够从不同的方向对材料施加作用力。They found that when the direction of stress was at right-angles to the tubes, it stiffened by 5.9%.当施力方向与碳纳米管成直角时,材料硬度提高5.9%;When it was in the direction in which tubes were pointing, the increase was only 4.3%.当作用力与碳纳米管所指方向一致时,材料硬度仅提高4.3%。What that means is still unclear, but it may be the key to understanding the phenomenon—and thus being able to replicate it with other ingredients.现在尚无法对其中的原因作出解释,但或许对于理解材料硬度变化是非常重要的—进而在其他原材料身上复制这类变化也有了可能。 /201212/217570He eventually found one, here in Ramsgate, teaching French, German, arithmetic and dictation to young boys at a school opened in this building by a Mr. William Stokes.他最终找到了一份工作,在拉姆斯哥特,他在这位威廉·斯托克斯先生的建筑开办的学校内教男孩子们法语,德语,算术和听写。This job was unpaid, just board and lodging.这份工作没有报酬,只提供食宿。But he was teaching and that pressed Vincent’s vocational buzzer.但他的教学使文森特一鸣惊人。The school was crummy, Dickensian, one might say.这所学校非常肮脏, 有人可能会说是狄更斯式的。The floors of the bedroom in which the boys slept were rotten, the windows broken.男孩们睡的卧室的地板腐朽不堪而且窗户破旧。And Vincent complained desperately about the bedbugs.而文森特对于臭虫疯狂抱怨。He did a couple of drawings out of the school window, of this view.他透过窗户外的景点画了几幅画,而这一景致。They’re rather delightful.它们相当讨人喜欢。 注:听力文本来源于普特201208/194530Science and Technolgy科技Another Earth?另一个地球?Home away from home远离家乡的家The existence of the most Earthlike planet yet has just been confirmed类地球行星的存在已刚被确认ONE of the more memorable slogans to come out of the climate-change talks in Durban over the past few days is: ;there is no planet B;. But what if there were? Over the past couple of decades astronomers have logged thousands of so-called ;exoplanets;—worlds which orbit stars other than the sun. On December 5th the scientists in charge of Kepler, a space telescope designed to look for such planets, confirmed their instruments discovery of its first Earthlike world. It is dubbed, rather unromantically, Kepler 22b.在过去几天的Durban气候变化会谈上提出的较难忘的口号之一就是;没有星球B;,但是如果有呢?在过去的几十年内,天文学家记载了数以千计的所谓的;外行星;---饶太阳以外的星球轨道运行的宇宙。12月5号,负责开普勒号的科学家确认他们的仪器发现了第一个类地球星体,开普勒号是专门为寻找这样的类地球星体而设计的太空望远镜。The existence of this planet, which circles a star 600 light-years away, in the constellation of Lyra, had previously been suspected. Kepler, which belongs to NASA, Americas space agency, works by observing dips in a stars brightness as a planet passes in front of it. It flags likely looking reductions as ;candidate planets;, of which Kepler 22b was one. But three passes are needed to confirm a planets existence, and Kepler 22b has now passed this test. Crucially, it orbits well within its stars ;Goldilocks zone;: neither too close nor too far away for liquid water (and therefore, perhaps, life) to exist on its surface.存在这么一个行星,它环绕天琴座星系中一颗600光年远的恒星运行,之前被怀疑的不存在,开普勒号,隶属于美国国家航空与宇宙航行局,即美国航天局,它通过观察当行星通过时恒星光亮度的变化来工作。它标识显现的光度弱化可能为候选行星,开普勒22b就是一个。但是一个行星的确认需要通过三个检测,开普勒22b现在已经通过检验。最重要的是,他环绕着其恒星的;适居带;很好地运行;不会太近也不太远(因此,可能,生命)液体水可能存在在上面。It joins two other Earthlike planets-Gliese 581d and HD 85512 b-discovered by another instrument within the past few years. In truth, the term ;Earthlike; is a stretch. Kepler 22b has a radius 2.4 times that of Earth, and if it is made from roughly the same stuff its surface gravity will also be about 2.4 times as strong. But NASAs astronomers remain unsure whether it is predominantly gaseous, liquid or solid.它加入了另外两个类地球行星——Gliese 581d 和HD 85512 b—在过去的几年里被另外的仪器发现的。事实上,;类地球行星;这个词言过其实,Kepler 22b半径是地球的2.4倍,如果它和地球的组成大致相同,它的表面引力也将大约高达地球引力的2.4倍。但是美国国家航天与宇宙航行局的天文学家仍不能确定它主要是气体的、液体的或是固体的。Nevertheless, Kepler 22b is the most promising exoplanet yet found. Unlike the others, which skirt the edges of their stars Goldilocks zones, Kepler 22b orbits comfortably within its own. NASAs researchers reckon its surface temperature is about 22°C, compared with 15°C (at least for now) on Earth. Its parent star is similar to the sun, again unlike those of the other two candidates, both of which orbit cooler, dimmer stars. Indeed Gliese 581ds parent is a red dwarf-the tiniest stellar species. That means its Goldilocks zone is so close to it that the planet may be tidally locked, as the moon is to the Earth. If that were the case, one side of Gliese 581d would be permanently lit (and heated) while the other experienced unending darkness.然而,Kepler 22b 是目前发现的最有希望的外行星。不像其他行星不在恒星的;适居带;,Kepler 22b 在它的;适居带;舒适地运行。美国国家航空与宇宙航行局的研究人员通过与地球表面温度15°C(至少现在是)比较,估算出它表面的温度大概是22°C。它的母恒星与太阳相似,这又与其他两个候选外行星不同,其他两个候选外行星都环绕较冷的、较昏暗的恒星运行。Gliese 581d的母恒星确实是一个红矮星---最小的星系。那意味着适居带;非常接近它以至于行星可能被潮汐力锁住,就像月亮对于地球一样。如果是那样的话,Gliese 581d的一面将会是常年光亮的(并很热),而另一面将会是无尽的黑暗。These three potentially habitable exoplanets may soon be joined by many more. In the two and a half years since its launch, Kepler has spotted 2,326 candidate planets. About 650 others have been discovered by other instruments. That plethora allows astronomers to start drawing conclusions about how common various sorts of planets are. Of Keplers haul, 9% seem to be of a similar size to Earth (though not all are in the Goldilocks zone of their star); a further 29% are Super Earths-planets substantially larger than Earth that are nevertheless rocky. Forty-eight of Keplers unconfirmed candidates look as if they orbit within their stars habitable zones; of those, ten seem to be Earth-sized.很快可能有更多的外行星加入这三个可能适合居住的外行星中。Kepler自发射以来的2年半里已经发现了2,326候选行星。其他仪器大约发现了另外650个行星。大量的行星使天文学家开始得出行星种类繁多的结论。Kepler捕获的行星中9%大小与地球相似(尽管不是所有的都在他们恒星的;适居带;);Kepler 发现的行星29%是超级地球---实质上比地球大,不过地球是岩石类行星。Kepler未能确认的候选行星48%看起来似乎是在;适居带;运行;其中,有10个与地球大小类似。The ultimate goal, of course, is to let astronomers make a plausible estimate of the total number of planets in the galaxy, of the number that could conceivably support life, and of the fraction of those that could (at least in theory) sustain human colonists. If only a few of Keplers possible Earthlike planets turn out to be real, that third number is likely to be in the millions.当然最终的目标是让天文学家对系的行星总数、确定可以维持生命的行星数和那些可以维持人类殖民者生命(至少在理论上)的行星比例做出一个接近可信的估算。如果Kepler类地行星中只有很少被明是真的,第三个数可能是数百万。Such knowledge will mark an historic transition, says Chris Lintott, an astronomer at Oxford University who is giving the Kepler team a hand with the data analysis, since the uncertainties around the question of whether life exists elsewhere will cease to be astronomical (how many suitable planets are there?) and become purely biological (how easy is it for life to get going, and how easy is it for it to become intelligent?). Based on the preliminary data, it looks as if there are numerous suitable planets. The science of exobiology may soon cease to be an oxymoron一位牛津大学的天文学家Chris Lintoot说这些知识是历史转变的标志,他对Kepler团队给以数据分析的援助,从此关于其他地方是否存在生命问题的不确定性将不再是天文学问题(有多少合适的行星),而是变成了纯粹的生物问题(生命开始难不难?进化到聪明难不难?)基于这些初始数据,似乎有许多合适的行星,外空生物学将不再是一个矛盾修饰。 /201210/202879

Business商业IT in Myanmar缅甸IT业Yangons digital spring仰光的数字之春An isolated country gradually goes online一个封闭的国家逐渐地走上了网络前线WHERE did BarCamp, a get-together of tech geeks (pictured), recently hold its biggest event since its founding in Silicon Valley seven years ago?七年前Barcamp(即国际研讨会网络)在硅谷成立,这个科技业怪才的聚会(见图),最近在哪里举行其最重大的活动呢?Not San Jose, nor Bangalore, nor even Singapore.不在圣何塞(哥斯达黎加首都),不在班加罗尔(印度南部城市),甚至也不在新加坡。On February 11th more than 5,000 developers and bloggers gathered in Yangon, the main city of Myanmar, one of the worlds most tech-starved places.2月11日,超过5000家开发商和客达人汇聚缅甸的大城市——仰光,一个世界上最乏科技的地方。The star speaker was the countrys opposition leader, Aung San Suu Kyi.本次集会的著名发言者是缅甸反对党领袖Aung San Suu Kyi(昂山素姬)。Myanmars government continues to surprise the world with its new-found tolerance for change.缅甸政府一再以其对新出炉的改革采取容忍态度而震惊世界。Its apparent willingness to nurture a fledgling IT sector is no exception.毫不例外,当局明显愿意培养一个刚刚起步的IT信息部门。Myanmar has lowered its firewalls, opening access to social-media sites such as Facebook and Twitter.缅甸已经放低了其防火墙,对外开放了如脸谱网facebook和推特twitter等社会媒体网站。People can international newspapers online or chat with family abroad via Skype.人们能够阅读国际在线新闻,或者通过skype和国外亲戚聊天。Sponsors of BarCamp included the telecommunications ministry.Barcamp的赞助方包括了政府通信部门。Though the government now acknowledges the importance of an IT industry for economic development, much work remains.尽管政府当局现在承认IT业对经济发展的重要性,但仍有很多的工作要做。Few people in Myanmar own computers and only a handful can afford the sort of connectivity that is commonplace elsewhere.少数人缅甸拥有自己的电脑,且其中仅仅一小撮人能付得起那种沟通无处不在的联通方式。Setting up an internet connection costs 0, and monthly packages range between and 0.设置一个互联网连接得花费850美金,每月租金40美金至150美金不等。A SIM card for a mobile phone will set you back 0.一张移动手机SIM卡将花掉你700美金。Yet demand for IT is soaring.然而,缅甸IT业的需求是猛烈剧增的。Firms from Asia and the West are paying unofficial visits, and local companies are scrambling to become their partners.来自西方和亚洲通信企业的非正式造访,缅甸仰光当地的公司正争先恐后地成为他们的合作商。The government faces a barrage of proposals on how to lower the cost of mobile phones and how to build data centres to compete with those in India and the Philippines.政府部门接到了一大堆关于如何降低手机成本和如何组建数据中心用以抗衡印度和菲律宾的建议书。A call centre was recently established, and there are even online-shopping sites in the works.最近建立了一个寻呼中心,甚至有一些在线购物网站正在筹划当中。Transactions online are widely expected to start this year: the infrastructure is y and a payment union has been formed.在线交易在大众期待下有望在今年运行:基础设施已经准备好,一个付联盟也已经形成。Yet despite these encouraging signs of liberalisation, no one expects Myanmars cyber-awakening to progress at broadband speed.虽然有这些鼓舞人心的自由开放化迹象,还没有人指望缅甸的网络发展会达到宽带速度。 /201211/207383

  • 襄樊红十字医院男科电话
  • 襄阳粉刺医院哪家排名比较好120信息
  • 襄阳一院看乳腺检查多少钱城市助手
  • 樊城区妇幼保健中医院治疗不孕不育多少钱
  • 襄阳华光医院治疗早孕多少钱国际卫生
  • 襄阳中医院好不好咨询知识襄阳谷城县妇幼保健院中医院治疗内分泌怎么样
  • 康泰健康湖北附属襄阳医院医院电话
  • 中医爱问襄阳第四人民医院新地址中医优惠
  • 襄阳中心医院治疗便秘怎么样
  • 老河口市妇幼保健中医院腋臭科中国解答
  • 襄州区人民医院治疗男性不育多少钱排名热点襄阳保康县人民中心医院官网
  • 枣阳妇幼一二医院做药流
  • 健步健康襄阳四院男科电话
  • 襄阳市第四医院包皮手术多少钱
  • 知道乐园襄阳医院治疗子宫内膜炎多少钱久久新闻
  • 豆瓣典范襄樊红十字医院上环咨询
  • 襄樊市第一人民医院不孕不育医院预约挂号最新频道襄阳第四人民医院官网
  • 度门户襄阳四院妇科预约光明社区
  • 枣阳市第一人民医院是公立的吗预约乐园
  • 枣阳市妇幼保健中医院看泌尿科怎么样
  • 襄州医院肛肠科
  • 放心分类襄阳市铁路医院网站
  • 平安对话襄阳治包茎要多少钱
  • 襄阳市中医医院做人流多少钱管解答
  • 襄阳第四人民医院肛肠科
  • 襄樊市中心医院无痛取环
  • 东风襄樊医院治疗便秘怎么样
  • 湖北化学纤维厂职工医院肛肠医院京东媒体
  • 普及活动襄阳中心医院电话周末有上班吗
  • 襄樊中医院医术信得过?
  • 相关阅读
  • 瞒天过海!集体耕地上建厂房!村民:相关部门集体哑火(三)
  • 暮影战神武灵攻略大全
  • 唐嫣赵丽颖吴昕林允儿李易峰和谁最有感(图)
  • 酒类电商双罢斗
  • 南京查处违规补缴社保证明份购房证明被注销
  • 内蒙古自治区政协原副主席赵黎平一审被判处死刑
  • 近日李念与刚斩获年北京青年电影节影帝的巩峥出现在街边
  • 徐娇穿白袜撑伞古典韵味十足邻家有女初长成
  • 单机斗地主下载:首存优惠
  • 小学生作业本开口说话曝光盗伐林木团伙
  • 相关推荐

    发表回复

    请遵守天涯社区公约言论规则,不得违反国家法律法规