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市中区人民医院引产多少钱济南人流医院预约电话Science and technology.科技。The search for alien life寻找外星生物Twinkle, twinkle, little planet闪烁吧,小行星An undervalued optical trick may help to find life in other solar systems一个不被人重视的光学方法可能能帮助寻找其他太阳系的生命MOST astronomical telescopes employ reflection to focus starlight. A concave mirror creates an image from this light using a design pioneered in the 17th century, by Sir Isaac Newton. Those telescopes that do not employ reflection use refraction. They have a system of lenses, an idea first used to look at the stars by Galileo.大部分天文望远镜都是运用的焦点星光的反射原理。早在17世纪,艾萨克.牛顿就开创性的利用这个光,让凹透镜产生了一个图像。那些不利用反射的望远镜利用的是折射。他们有透镜系统。利用透镜系统的想法最早是伽利略用来观测星星的。But there is a third way to focus light. A century and a half after Newton, and more than two after Galileo, a Frenchman called Augustin-Jean Fresnel worked out that you can do it using diffraction. A set of concentric rings, alternately transparent and opaque, will scatter and sp light waves in a manner that causes them to reinforce each other some distance away, and thus form an image. The rings are known as a zone plate. And Fresnel#39;s countryman, Laurent Koechlin, of the Midi-Pyrenees observatory, thinks zone plates are the way to find out if there is life on other planets.但还存在第三种聚焦光源的方法。在牛顿利用星光的150年后,伽利略的透镜系统的两百多年后,一个名叫奥古斯丁.让.菲涅尔的法国人想到也可以利用衍射来达到目的。一组兼有透明和不透明的同轴环可以分散和传播光波,并且在稍远的地方可以再使他们重新聚焦,由此形成一个图像。这些环被称作波带片。法国南比利牛斯天文台劳伦.凯什兰认为波带片可以用来寻找其他星球上是否存在生命。Seeing oxygen in another planet#39;s atmosphere would be a giveaway of biological activity because the gas is so reactive that it needs to be continuously renewed. That would almost certainly mean something akin to photosynthesis was going on, for no known non-biological process can produce oxygen from common materials in sufficient quantity. Looking at such an atmosphere, though, is tricky. Stars are so much brighter than the planets which orbit them that their light overwhelms the small amount reflected from a planet#39;s surface. And this is where Fresnel comes in.在其他星球的大气层发现氧气则表明这个星球上有生物活动,因为氧气是一种非常活跃的气体,所以他需要不停的更新。而这也就基本上意味着星球上进行着某些类似于光合作用的活动,因为在我们已知的非生物学过程中,没有一种过程可以在普通材料供应充足的情况下产生氧气。然而,观测到这样的大气层也是非常难的。恒星比以他们为轨道运行的行星亮得多。他们的光盖过了从行星表面上反射过来的少量光。而这也就是菲涅尔的突破口。Fresnel telescopes have not been developed in the past because the image formed by one that was large enough to rival a useful-sized reflecting telescope would be several kilometres from the zone plate. But Dr Koechlin does not worry about that, because his Fresnel telescope will be in space. Free of the confounding effects of the Earth#39;s own atmosphere, it will be able to isolate images of alien planets, make spectra of the light from their air, and examine those spectra for the characteristic dark lines that are caused by part of the light being absorbed by particular gases-oxygen among them.过去,菲涅尔设计的望远镜还制造不出来,因为要想使衍射望远镜的大小和正常使用的反射望远镜大小相同,它所产生的图像就会距离波带片数千米远。然而,凯什兰士并不为此担心,因为他的菲涅尔望远镜将会在太空中。脱离了地球大气层的混淆效应,望远镜将能够分离外星生物的图像,在他们的大气中制作出来光谱,并且为这些有特点的暗线检查光谱。这些暗线部分是由特殊气体——大气中的氧气——所吸收的光产生的。Plate tectonics行星构造地质学Space telescopes are nothing new, of course, and several more are in the works (see article). But existing plans to photograph extrasolar planets in this way involve orbiting arrays of reflecting telescopes all pointing in exactly the same direction. An array is needed because a single mirror big enough to do the job of separating star from planet would be too large to launch. The problem is the word ;exactly;. It means just that. The formation would have to fly with a precision of a few billionths of a metre.当然,太空望远镜并不是什么新事物,并且已经有几个已经在使用中了(见文章)。但是在现在的计划中,利用这种方法给太阳系以外的行星拍照就需要让多组的反射望远镜在轨道运行的时候全部精准的朝向同一个方向。由于一个体积足够大到能够将恒星与行星分开的单一镜面将会由于体积太庞大而无法发射,因此一组反射望远镜就是必须的。而问题就出在;精准;上。它就如字面意思一样,要精准到十亿分之一米。Using a zone plate instead of a mirror gets around this. Because the plate is flat, it can be made of plastic and folded up for launch. Size thus ceases to be an issue. And although a second satellite containing the ;eyepiece; (a special lens that also uses Fresnel optics, and a camera to record the image) must fly at the focus, the accuracy required is only hundredths of a metre, not billionths. That, Dr Koechlin reckons, gives Fresnel optics a big advantage over Newtonian ones.用波带片代替镜面在轨道运行。因为波带片表面是平的,他可以用塑料制作而成,然后折叠起来发射。而尺寸大小就不再是问题。并且,尽管还必须有一个含有;目镜;(也是一种运用菲涅尔视觉的特殊透镜,也是一种记录图像的相机)的卫星在焦点上运行,所需要的精准度也只是百分之一米。凯什兰士认为,这将是菲涅尔视觉超越牛顿的设计的一大优点。To test the idea, he and an international consortium of his colleagues have built a ground-based prototype. This is a piece of copper foil 20cm square that has 696 rings, a portion of which is reproduced above. Because it is this small, its focal length is only 18 metres. In order that the foil does not fall apart, each transparent ring is actually a series of curved slots in the copper rather than a continuous gap. This, though, does not affect the system#39;s optical properties and it can, indeed, see small, faint objects that are near large, bright ones.为了检测这一想法,他和他各国的同事建立了一个陆基的雏形。这是一片20平方厘米的铜箔,它有696个环。铜箔的一部分是再生的。因为它体积偏小,所以它的聚焦只有18米。为了不让铜箔散开,每一个透明的环实际上都是铜箔里的一系列的曲线轮槽,而不是连续的空隙。尽管如此,这并不影响整个系统的视觉特性,并且,它也确实能够看见巨大且明亮的恒星旁边那些小型且微弱的物体。When Dr Koechlin and his team pointed it at Mars they could distinguish that planet#39;s two tiny moons-a task which would require a Newtonian telescope with a mirror at least 30cm across. And when they aimed at Sirius they could see the dim white-dwarf which orbits what is the brightest star in the night sky. Extrapolating from these results, they think that an orbiting zone plate measuring somewhere between 15 metres and 40 metres across will be enough to distinguish the spectrum of an Earthlike planet at a distance of 30 light-years. With that, they should be able to find out if mankind really does have any next-door neighbours, and Fresnel will have come into his own at last.当凯什兰士和他的团队观测火星时,他们可以分辨火星的两个微小卫星——这样的任务如果是利用牛顿的望远镜则需要一个直径最少长达30厘米的镜面。并且,当他们观测天王星时,他们能够看见暗淡的白矮星。它围绕着夜空中最亮的那颗星运行。从这些结果推测,他们认为,一个直径在15到40米、并且在轨道上运行的波带片足够在30光年以外的距离分辨一个与地球相似的行星的光谱。如此一来,他们就应该能够找到人类是否还有其他邻居,而菲涅尔也最终能实现自己的想法。 /201208/194545济南省中心医院人流收费标准 In its latest step to attract Chinese smartphone users, e-commerce company Alibaba Group Holding Ltd. said it is planning to launch a mobile gaming service soon.阿里巴巴集团(Alibaba Group)表示,计划不久推出手机游戏务,这是该公司吸引中国智能手机用户的最新举措。Alibaba is considering integrating its new mobile gaming service into its messaging app, Laiwang, as well as its Mobile Taobao app for online shopping, a person familiar with the matter said. It is also planning to launch the gaming service as a standalone app, the person said.知情人士表示,阿里巴巴考虑将新的手机游戏务整合入聊天应用“来往”以及淘宝手机客户端。该公司还计划推出独立的游戏务应用。In the world of gaming and other mobile-based services, Alibaba faces powerful competitor Tencent Holdings Ltd., a giant in online gaming and social networking services. Many analysts view Tencent as a leader in mobile-based businesses in China because of its popular WeChat instant-messaging app, which has over 272 million monthly active users worldwide according to the company. Tencent could use WeChat#39;s massive user base to offer additional mobile services such as gaming or e-commerce, analysts say.在游戏和其他手机务领域,阿里巴巴都将面临腾讯控股有限公司(Tencent Holdings Ltd. , 简称:腾讯控股)的强大竞争。由于腾讯的微信聊天工具(据腾讯称,微信每个月的全球活跃用户达到2.72亿)很受欢迎,许多分析师将腾讯视为中国移动业务领域的领导者。分析师们表示,腾讯可能利用微信庞大的客户群来推出其他的移动务,例如游戏或电子商务。Alibaba#39;s push into mobile-based services hasn#39;t always been smooth. It launched Laiwang more than a year ago, but the app, which competes against WeChat, struggled to gain popularity. In September, a person familiar with the situation said Alibaba was in talks with China Telecom Corp., to have the app preinstalled in smartphones sold by the country#39;s third-largest mobile carrier. According to Alibaba, Laiwang had more than 10 million registered users as of November.阿里巴巴进军移动务领域的过程并非一帆风顺。该公司1年前推出了用来和微信抗衡的“来往”,但是该应用却很难普及开来。知情人士去年9月份表示,阿里巴巴正在与中国第三大移动运营商中国电信股份有限公司(China Telecom Co., 简称:中国电信)进行谈判,希望能在中国电信出售的智能手机中预装来往软件。据阿里巴巴,截至去年11月份来往的注册用户超过了1,000万。Alibaba dominates China#39;s e-commerce market with its Taobao and Tmall shopping sites, but one of the biggest challenges it faces is how to hold onto its vast user base when more Chinese Internet users access online services from smartphones. To meet this challenge, Alibaba has made several acquisitions to strengthen its mobile-based services. Last year, it took an 18% stake in Sina Corp.#39;s Twitter-like Weibo service and integrated some of Taobao#39;s e-commerce services with the microblog. It also bought a 28% stake in mobile mapping firm AutoNavi Holdings Ltd., a move that could enable Alibaba to send location-based ads to smartphone users.阿里巴巴凭藉旗下的淘宝网和天猫网在中国的电子商务市场占据了主导地位,但是该公司面临的最大挑战之一就是,在越来越多的中国互联网用户通过智能手机使用网上务的情况下,如何留在庞大的客户群。为了迎接这些挑战,阿里巴巴进行了数笔收购交易,以加强自身的移动务。去年该公司收购了新浪(Sina Corp.)微业务18%的股份,并把淘宝网的一些电子商务务与微进行了整合。阿里巴巴还收购了数字地图公司高德软件有限公司(AutoNavi Holdings Ltd.) 28%的股份,藉此阿里巴巴可以向智能手机用户发送定位相关的广告。 /201401/272945Buses have never been the most glamorous form of transportation. But that is set to change with the Superbus, a 15ft-long, six-wheeled behemoth that on first glance looks like a cross between the Batmobile and a stretched limousine. It can carry 23 passengers and reach speeds of up 255kph, although finding a parking space might prove difficult. A design team from TU Delft University has unveiled the Superbus at the World Exhibition of the International Association of Public Transport (UITP) in Dubai.巴士从来不是最时髦的交通工具,但随着一种“超级巴士”的出现,这一局面可能即将改变。这种巴士长度为15英尺(4.6米),有6个轮子,乍一看就像是某种介于蝙蝠侠座驾和拉长性豪华轿车之间的变形。它可以搭载23名乘客,行驶速度可达每小时255公里。当然,想在城里找到一处合适的停车场可能比较困难。这种设计新颖的汽车出现在了正在迪拜举行的国际公共交通联合会(UITP)第59届世界论坛暨城市交通展的展台上。其设计团队来自荷兰代尔夫特科技大学。 /201104/131955济南阳光医院妇科检查好吗

济南做无痛人流医保报销吗莱芜市四维彩超价格 Money really does grow on trees – at least in Australia.树上真的可以长黄金——至少在澳大利亚是如此。Scientists have found gold in the leaves of eucalyptus trees.科学家们在桉树树叶里找到了黄金。The particles are much too small to be seen with the naked eye but have been detected using a type of x-ray that is especially good at picking up trace amounts of metals and minerals.这种树叶中含有的黄金粒子十分微小,不足以凭肉眼观察到,但是科学家们通过一种专门探查微量金属和矿物的X射线仪器发现了它们。However, gold hunters shouldn’t start felling gum trees in the hope of becoming rich.但是,猎金者们大概不能通过伐木来采金致富。Study leader Mel Lintern told the Brisbane Times: ‘If you had 500 eucalyptus trees growing over a gold deposit, they would only have enough gold in there to make a wedding ring.’科研小组的领队梅尔·林特恩对记者说,“如果让500棵桉树生长在一个金矿上,这些树中收集到的金子大概足够打一枚金戒指。”The real value of the study is that nature’s own version of gold leaf could provide mine companies with an inexpensive and environmentally friendly indicator of where to drill test sites.这一研究的真正价值在于,这种自然界而非小说里出现的金叶子可以充当金属探测器,这种探测方式既环保又方便,可以告诉探勘者在哪里能开采到金子。The study by the Commonwealth Scientific and Industrial Research Organisation in Western Australia showed levels of the precious metal were highest in trees growing directly over gold seams, one of which was 115 feet down.这项研究成果是由澳大利亚西部的联邦科学与工业研究组织成员做出的,该研究组织发现,直接生长在金矿层上的桉树叶中的黄金含量是最高的,其中一个金矿在地下115英尺(约35米)深。The researchers believe the gold was taken up by the trees’ extensive roots from while scouring for water during times of drought.研究者们相信,树叶中含有的金子是树根在干旱时期、四处蔓生以寻找水源时被吸取到树中的。It was then transported through the tree to the leaves, where concentrations are higher than in the twigs, trunk or surface soil.被树根吸取的金子被输送到枝干和叶子中,金子在叶子中的密集度比在树枝、树干和表层土壤中都要高。The researchers said: ‘Gold is probably toxic to plants and is moved to extremities, such as leaves in order to reduce deleterious biochemical reactions.’研究者说,“对于植物来说,黄金是有毒的,因此黄金被传送至树叶等植物的末端,这样可以减少破坏性的生化反应。”Writing in the journal Nature Communications, they said it was the first time that gold had been found naturally incorporated into a living thing.这一研究成果已经在《自然通讯》期刊上发表,科学家称,这是人们首次在植物体内发现自然贮藏的黄金。 /201310/262668济南妇幼保健医院环境

济南山东省中医院是正规医院吗 Regulations proposed by the Chinese government for the country#39;s burgeoning smartphone market, aly the largest in the world, are prompting concern from industry groups representing companies such as Apple Inc. and Google Inc.中国政府针对本国迅速成长且已居世界第一的智能手机市场拟议的监管法规引起代表苹果(Apple Inc.)、谷歌(Google Inc.)等公司的行业团体的担忧。The draft law, for which the public-comment period ends this weekend, is the beginning of China#39;s effort to regulate the fast-growing mobile-applications market and could force industry leaders to censor what applications they offer, build phones with China-mandated security requirements and include features that would help the government identify users.《关于加强移动智能终端进网管理的通知》(征求意见稿)公开征求意见的时间即将于本周末结束。这标志着中国开始采取措施监管快速成长的移动应用市场,并可能会强制要求业内领头企业审查它们提供的应用程序,按中国安全规范生产手机,并加入有助于政府识别手机用户的功能。China#39;s Ministry of Industry and Information Technology says the proposed rules are designed to protect the personal information of smartphone users. Chinese media have reported that the regulation would target malicious software─common on cheap, unbranded smartphones in China-that can steal users#39; personal information and incur charges by sending text messages.中国工业和信息化部说,这些拟议中的规定是为了保护智能手机用户的个人信息。中国媒体曾报道,这部法规将打击可能窃取用户私人信息、通过发送短信产生费用的恶意软件。这类软件在中国价格便宜的无牌智能手机上相当常见。Industry groups say the effect on companies would likely be higher costs and slower growth in one of the most important markets for electronics suppliers. Apple sold two million smartphones in China in the first quarter, Samsung Electronics Co. Ltd. sold 7.8 million and Motorola Mobility Holdings Inc. sold 1.5 million, according to Analysys International.行业团体认为,这些规定可能会造成企业成本增加,并使电子产品供应商在世界最重要的市场之一的增长速度放缓。据易观国际(Analysys International)的数据,今年一季度苹果在中国市场卖出智能手机200万部,三星电子(Samsung Electronics Co. Ltd.)卖出780万部,托罗拉移动公司(Motorola Mobility Holdings Inc.)卖出150万部。The size of China#39;s total smartphone market has more than tripled in less than three years, with 31.2 million smartphone devices sold in the first quarter, compared with just 7.2 million in the fourth quarter of 2009, Analysys says.不到三年时间,中国智能手机市场的总体规模就扩大了三倍还多。据易观国际的数据,今年一季度中国市场智能手机销量为3,120万部,相比之下2009年第四季度的销量才720万部。The rapid adoption of new mobile devices and applications by Chinese consumers has outpaced authorities#39; ability to regulate them. China#39;s mobile-apps market currently is largely unregulated.中国消费者接纳新手机和应用程序的速度已经超出了有关部门监管能力的提升速度。目前中国的移动应用市场基本上处于无监管状态。The proposed measures mandate that handset makers ensure that preloaded apps and those made available through other means meet with Chinese laws in order to be licensed to sell the phones in China. That could mean companies would be forced to remove applications deemed offensive or antigovernment by China from devices and app stores offered on phones.征求意见稿规定,手机生产商要获得在中国市场出售手机的牌照,必须确保预装的、或以其他方式提供用户安装的应用软件遵守中国法律。这意味着企业将被迫从手机上、从手机应用商店中删除被中国视为有冒犯性或反政府的应用程序。The proposed law also says new phones must be made in accordance with Chinese standards. If new standards put forth by the government-guided China Communications Standards Association are approved, the law could force handset makers to cooperate with China#39;s government to identify customers and track their app use.征求意见稿还规定,新手机必须按中国标准生产。如果政府指导下的中国通信标准化协会(China Communications Standards Association)制定的新标准得到批准,拟议中的法规就有可能强制要求手机生产商配合中国政府识别用户身份并跟踪他们对应用软件的使用。 /201206/188675济南早孕b超检查多少钱山东济南阳光妇科评论怎么样



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