亚洲免费av电影一区二区三区,日韩爱爱视频,51精品视频一区二区三区,91视频爱爱,日韩欧美在线播放视频,中文字幕少妇AV,亚洲电影中文字幕,久久久久亚洲av成人网址,久久综合视频网站,国产在线不卡免费播放

        ?

        國際科技信息

        2011-10-26 09:51:26世界銀行今日發(fā)布報告稱由于在教育和科研方面存在缺陷東亞的大學在推動本國經濟增長的進程中沒能起到它們應起的作用
        中國科技信息 2011年21期
        關鍵詞:研究

        世界銀行今日發(fā)布報告稱,由于在教育和科研方面存在缺陷,東亞的大學在推動本國經濟增長的進程中沒能起到它們應起的作用。

        該報告分析了造成此現(xiàn)象的原因,其中最重要的是職工對高級技能的需求與高校所提供的培訓不匹配。此外,研究小組還發(fā)現(xiàn)大學研究并沒有為工業(yè)和商業(yè)技術

        國際科技信息

        Hubble telescope captures new 'maps' of dark matter--But on this evidence, we may just have to take their word for it

        Hubble's Cluster Lensing and Supernova Survey- CLASH - is charting the distribution of dark matter in 25clusters.

        The Hubble scientists are scanning cluster galaxies, the most massive objects in the universe held together by gravity, to see if light is distorted by the dark matter inside the clusters.

        The astronomers say the distortions produced by MACS 1206is evidence that the galaxies are largely 'made' of dark matter.

        The distortions shown in the images would be far weaker if the only mass in MACS 1206was the mass of the stars and planets we can see.

        CLASH uses the Advanced Camera for Surveys and the Wide Field Camera 3, the CLASH survey to covers a broad wavelength range, from ultraviolet to near infrared. Astronomers need the diverse colors to estimate the distances to lensed galaxies and study them in more detail.

        These maps are being used to test previous results that suggest that dark matter is more densely packed inside clusters than some models predict.

        MACS 1206lies 4.5billion light-years from Earth.

        The era when the first clusters formed is not precisely known, but is estimated to be at least 9billion years ago and possibly as far back as 12billion years ago.

        If most of the clusters in the CLASH survey are found to have excessively high accumulations of dark matter in their central cores, then it may yield new clues to the early stages in the origin of the universe.

        哈勃望遠鏡獲取迄今最精確暗物質分布圖

        借助哈勃空間望遠鏡和宇宙引力透鏡效應,科學家們日前成功地獲取了一個巨型星系團中暗物質迄今最精確的分布圖。

        暗物質是一種神秘莫測的不可見物質,它幾乎占據(jù)了宇宙1/4的物質和能量,但是除了引力作用之外,它們和“常規(guī)”物質不發(fā)生任何相互作用??茖W家們之所以知道宇宙中存在暗物質,并不是因為他們“看見”了暗物質,而完全是通過看不見的暗物質對可見物質施加的引力影響間接地獲得關于它們的信息。

        當大量暗物質聚集,就像常規(guī)物質組成的星系團中會包括數(shù)百甚至數(shù)千的星系一樣,聚集的暗物質會產生巨大的引力作用,使其背后遙遠星系發(fā)出的光線在經過其附近時發(fā)生彎曲,從而形成類似透鏡的效應。地球上的天文學家已經拍攝到多幅同一個星系在引力中心四周形成多幅圖像和假象的現(xiàn)象,這稱為“引力透鏡效應”。引力透鏡效應可以作為我們很好的測量工具,用以估算一個星系中暗物質的多少,但到目前為止,天文學家們對于暗物質具體到底存在于哪個位置還是一無所知。

        但是這次不同,借助哈勃空間望遠鏡搭載的先進巡天相機(ACS),天文學家們已經找出了一個叫做阿貝爾1689(Abell 1689)的星系團中暗物質分布的具體位置。

        “使用其他方法,研究者只能是通過很多觀測數(shù)據(jù)去拼湊一個暗物質的質量分布情況,找出一種最符合觀測數(shù)據(jù)的分布模型,”美國宇航局噴氣推進實驗室(JPL)的天文學家丹科爾(DanCoe)在一次新聞發(fā)布會上表示,“但如果使用我們的方法,研究者將可以直接獲得暗物質的質量分布圖,而不必去猜測和拼湊。”

        阿貝爾1689星系團距離地球22億光年,含有大約1000個星系和10000億顆恒星。通過對比哈勃的圖像和之前早先的觀測數(shù)據(jù),研究人員從中挑選出了42個不同背景星系的135張不同照片?!鞍l(fā)生引力透鏡效應的天體照片就像是一個大大的迷宮,”科爾說。“我們所做的,就是第一次對阿貝爾1689星系團的內部質量進行排布,以便找到某種質量分布模式,在這種模式下將產生我們所觀測到的背景星系引力透鏡效應。”

        科爾和同事們在哈勃望遠鏡的圖像上疊加上暗物質的位置信息(即題圖中的藍色物質)。這一結果已經發(fā)表于11月10號的《天體物理學報》,在這一份研究論文中,科爾和同事們確認了阿貝爾1689星系團中的暗物質量要比先前研究人員們根據(jù)其星系規(guī)模做出的估算值要高。

        這一多出的物質量說明星系團在宇宙早期形成的年代要早于天文學家們原先的估計。暗物質的引力作用使物質聚集,但這一過程卻受到另一種更加神秘的強大力量的阻礙,這就是“暗能量”它的主要效應是將物質推開。一旦早期宇宙中暗能量扮演了重要角色,星系團要想聚集在一起難度就會大得多。

        “因此,星系團的形成應當在此之前數(shù)十億年便開始形成,以便形成我們今天所看到的宇宙?!笨茽栒f?!霸谠缙谟钪嬷?,宇宙空間更小,暗物質的密度也更高。阿貝爾1689星系團似乎在誕生初期就聚集了大量周遭的物質。在那之后,這個星系團便一直帶著這多余的質量,直到今天被我們觀測到?!?/p>

        這一研究成果是一個名為“哈勃星系團透鏡和超新星巡天”(CLASH,縮寫意為“撞擊”)的一部分。在接下來的三年時間內,該計劃還將利用哈勃空間望遠鏡觀測25個星系團,總觀測時長將達一個月。

        Sun's 11-year cycle means we're in for Arctic freeze this winter, say scientists

        It's been a lovely Indian summer - but it could come back to bite us.

        That's what scientists predict after working out the first ever pattern of activity for the sun.

        According to research, the sun runs on an 11-year cycle -and this affects winter weather over the northern hemisphere.

        The study says low solar activity can contribute to cold winters in the UK, northern Europe and parts of America.

        Which is bad for us - because the sun is just emerging from a so-called solar minimum, when solar activity is at its lowest.

        It means after a baking hot September, we could be in for a repeat of last year's big freeze.

        But the study also raises the possibility that weathermen can predict cold winter weather over the northern hemisphere using the solar cycle.

        Dr Adam Scaife, from the Met Off ce, one of the study's authors, said: 'Our research establishes the link between the solar cycle and winter climate as more than just coincidence.

        'We've been able to reproduce a consistent climate pattern, conf rm how it works, and quantify it using a computer model.

        'This isn't the sole driver of winter climate over our region, but it is a signif cant factor and understanding it is important for seasonal to decadal forecasting.'

        Up until now, researchers have only managed to see a weak link between solar activity and winter weather.

        It was understood that when the sun is less active, we're more likely to see weak westerly winds during the winter in the northern hemisphere.

        This pattern suggests that easterly winds could bring cold weather from the continent to the UK.

        But scientists have struggled to incorporate these ultraviolet (UV) signals into climate models.

        Today's f ndings, published in Nature Geoscience, used satellite measurements from NASA's Solar Radiation and Climate Experiment (SORCE) to reveal that differences in UV light reaching the Earth during the 11-year solar cycle are larger than previously thought.

        The satellite, launched in 2003, is the first ever to measure solar radiation across the entire UV spectrum.

        Professor of atmospheric physics, Joanna Haigh from Imperial College London, said: 'The instrument on the SORCE satellite divides UV light up into small wavelength regions, providing good spectral resolution.

        'Before this, climate models used broad spectral bands, so couldn't reveal the solar signal.'

        Using this new information in a Met Off ce climate model, researchers from the Met Off ce and the University of Oxford demonstrated that it's possible to reproduce the effects of solar variability which show up in climate records.

        It seems that in years of low UV activity, unusually cold air forms over the tropics in the stratosphere, around 30miles up.

        This is balanced by a more easterly f ow of air over the mid latitudes – a pattern which then makes its way down to the Earth's surface, bringing easterly winds and cold winters to northern Europe.

        But when solar activity is higher than usual – around the peak of the 11-year solar cycle – the opposite happens: strong westerly winds bring warm air and so milder winters to Europe.

        Lead author Sarah Ineson, from the Met Office, said: 'What we're seeing is UV levels affecting the distribution of air masses around the Atlantic basin.

        'This causes a redistribution of heat – so while Europe and the US may be cooler, Canada and the Mediterranean will be warmer, and there is little direct impact on global temperatures.'

        太陽活動影響地球天氣北半球將迎來寒冬

        科學家表示太陽的11年活動周期能夠影響北半球的冬季天氣。研究指出較弱的太陽活動與英國、歐洲北部和美洲部分地區(qū)的寒冷有關。目前,太陽正進入所謂的“太陽活動極小期”。這也就意味著,在經歷了9月的酷暑之后,北半球將再次迎來2010年那樣的寒冬。

        這項研究發(fā)現(xiàn)提高了天氣預報人員利用太陽活動周期預測北半球冬季天氣的可能性。研究論文作者、英國氣象局的亞當·斯凱菲博士表示:“我們的研究發(fā)現(xiàn)太陽活動周期與冬季氣候之間的聯(lián)系并不是一種巧合。我們能夠找到一個可靠的氣候模式,確定其如何運轉并通過電腦模型進行量化。太陽活動并不是影響我們地區(qū)冬季氣候的唯一因素,但卻是一個重要因素。加深對太陽活動影響的了解對預測天氣非常重要?!?/p>

        直到現(xiàn)在,研究人員仍只發(fā)現(xiàn)太陽活動與冬季天氣之間存在較弱的聯(lián)系。太陽活動較弱時,北半球的冬季更有可能出現(xiàn)較弱的西風。在這種氣候模式下,東風能夠將大陸的寒冷天氣帶到英國。

        一直以來,科學家便很難將紫外線信號融入氣候模型。根據(jù)刊登在《自然·地球科學》上的研究發(fā)現(xiàn),研究人員利用美國宇航局“太陽輻射和氣候實驗”衛(wèi)星(SORCE)的測量數(shù)據(jù),揭示出11年的太陽活動周期中抵達地球的紫外線變化情況,所存在的差異超出此前的預計。這顆衛(wèi)星2003年發(fā)射升空,是第一顆在整個紫外光譜測量太陽輻射的衛(wèi)星。

        倫敦帝國學院大氣物理學教授喬安娜·海赫指出:“SORCE衛(wèi)星攜帶的設備能夠將紫外線分割成小波長區(qū),提供出色的光譜分辨率。在此之前,氣候模型使用較寬的光譜帶,無法揭示出太陽信號?!蓖ㄟ^將這些新信息融入氣象局的氣候模型,氣象局和牛津大學的研究人員證明“復制”太陽活動變化產生的影響具有可行性。

        研究發(fā)現(xiàn),在紫外線較弱的年份,距地面30英里(約合48公里)的熱帶同溫層形成異乎尋常的冷空氣。與此同時,中緯度地區(qū)上空出現(xiàn)更多東風,進而達到一種平衡。這種現(xiàn)象隨后向地球表面移動,為歐洲北部地區(qū)帶來東風并迎來寒冬。當太陽活躍程度超過正常水平時——處于11年活動周期峰值左右——便會出現(xiàn)相反的現(xiàn)象,強烈的西風帶來暖空氣,讓歐洲迎來溫冬。

        研究論文主執(zhí)筆人、氣象局的莎拉·伊納森表示:“根據(jù)我們的研究發(fā)現(xiàn),紫外線水平影響大西洋盆地周圍的氣團分布,導致熱量重新分配。也就是說,在歐洲和美國出現(xiàn)低溫天氣時,加拿大和地中海卻較為溫暖。這種現(xiàn)象只能對全球溫度產生極少的直接影響?!?/p>

        How Black Death Kept Its Genes but Lost Its Killing Power

        In f ve years, Black Death wiped out an estimated 30to 50percent of Europe's population. This medieval plague was caused by the bacterium Yersinia pestis, which still circulates among humans. Genetic clues as to what might have made it so deadly, however, had remained interred with the tens of millions of victims.

        After careful extraction of genetic material from victims' teeth, a team of researchers has sequenced 99percent of the Plague's genome—the f rst whole-genome reconstruction of a disease from skeletal remains. The draft genome is described online October 12in Nature. (Scientific American is part of Nature Publishing Group.)

        The 660-year-old plague DNA was isolated from four victims, who had been exhumed from London's East Smithf eld Cemetery in the 1980s by the Museum of London Archaeology. To get samples from the skeletal remains, physical anthropologist Kristen Bos of McMaster University in Ontario and a colleague found themselves "wiggling the teeth out of the skulls at the Museum of London," she said in a Tuesday press brief ng about the new study.

        After carefully extracting genetic material from the inner pulp chamber of the teeth (so as not to damage their exteriors), the team created what Bos called a genetic "f shing rod," baited with molecules from modern-day Y. pestis. With that as a lure, "we were able to essentially f sh out the small preserved fragments of Yersinia pestis DNA" and separate it from the stew of human, bacterial and other genetic material that had accumulated during centuries in the soil. (The team described the actual method, which uses high-throughput DNA sequencing and microRNA enrichment, in an August Proceedings of the National Academy of Sciences paper.)

        The genome now gives researchers a sort of "fossil" to start to map out the bacterium's phylogenetic tree. They discovered that the Black Death that devastated Europe between 1347and 1350was likely close to the common ancestor of all extant Y. pestis strains, (which likely arose—from the soil bacterium Yersinia pseudotuberculosis—between 1200and 1340).

        If this was "the first big pandemic with disseminated Yersinia pestis in humans," as Johannes Krause, of the University of Tübingen's Institute for Archaeological Sciences, asserted at the briefing, then previous plagues, such as the sixthcentury Plague of Justinian, were either caused by a completely different pathogen or by a strain of Y. pestis that proceeded to go completely extinct.

        The new family tree can also help researchers examine related groups, such as the types of plagues that currently affect only rodents (such as Microtus strains and those that have been found in Chinese marmots)—and what genetic changes might need to occur to allow them to infect humans.

        The sequenced strain has some 4.7million base pairs. When compared with the modern version (based on 17different genomes), there are just 90genetic substitutions. That such few genetic changes occurred over the years, Krause said, was "really surprising."

        Among these changes, none obviously explains ancient Black Death's virulence, Hendrik Poinar, also of McMaster, said during Tuesday's prepublication brief ng. "There's no particular smoking gun."So if the slight genetic differences in the disease were not responsible for its drastic change, what did make it so deadly in the 14th century that, as Bos described it, "people honestly thought it was the end of the world"?

        Much of the mortality might be explained by situational factors, Poinar explained. Cooler climatic conditions and an excess of rain had led to failed crop harvests and widespread hunger, in addition to large numbers of people living in crowded—and already pathogen-filled—medieval cities. "You probably had an immunocompromised population, living under very stressful conditions," Poiner said. Add to that a "population being hit by Y. pestis maybe for the first time," and "Black Death was the perfect storm."

        Humans have also adapted to the disease. The global population has likely built up some immunity from centuries of exposure to the pathogen. And even before the modern era, virulence was likely quelled by cultural adaptations, Krause noted. During the first outbreak, no one knew what kind of disease it was nor how to treat it, he said. During subsequent outbreaks, however, "people had already developed some kinds of adaptations—they had developed quarantines, they had developed first aid to treat patients with the symptoms."

        加拿大科學家主導成功破解黑死病基因密碼

        加拿大

        麥克馬斯特大學“古代DNA中心”主管波拿亞和德國圖賓根大學克勞斯領導的研究小組成功破解黑死病基因密碼,成果報告見于12日出版的《自然》期刊上。

        波拿亞表示,即使是一年前,想要取得這種級數(shù)的基因資料,可以說是發(fā)白日夢。

        他表示,他跟同事估計黑死病有如此殺傷力,可能是該種病原首次入侵人類,亦不會有人有抗生素作保護,加上當時的環(huán)境令疾病快速傳播,包括房屋和城市非常擠迫、欠缺衛(wèi)生設備、人們普遍營養(yǎng)不良以及尚未發(fā)現(xiàn)抗生素和抗病毒藥物等。

        波拿亞指出,曾研究基因組的抗生素專家相信,將治療今天瘟疫的藥物用于14世紀,應該同樣有效。

        在英國倫敦東部的倫敦塔附近一個大規(guī)模的黑死病死者墓穴中,從掘到的人類牙齒發(fā)現(xiàn)了DNA破片,讓科學家得以完成這種古代鼠疫桿菌的完整序列。研究人員是從4副顎骨的牙齒取得DNA,4名死者中,兩人是成年女性,另1人是未能確定性別的青少年,至于第4人的性別和年齡均無法識別。他們利用現(xiàn)代鼠疫桿菌基因序列做樣本,得以完成14世紀瘟疫的基因排列。

        波拿亞表示,仍未能肯定基因排列的正確順序,若能掌握或許有助解釋古代細菌為何如此致命。

        研究人員亦跟美國的科學家協(xié)作嘗試尋找該等基因的改變。

        科學界對于自1347年到1351年肆虐的黑死病成因,長期爭論不休。部份科學家認為是一種病毒性出血熱引致,這種引發(fā)瘟疫的流行病學模式跟今天的瘟疫明顯有別。

        波拿亞的研究開創(chuàng)性地將肆虐多個世紀的一種前所未見、殺傷力極大的細菌的演化繪成圖表。時至今日,這種細菌仍在發(fā)展中國家局部地區(qū)肆虐。

        據(jù)此間的星島日報13日報道,14世紀中期歐洲發(fā)生長達5年的黑死病恐慌期,大約造成5000萬人死亡。

        East Asia's Universities Need To Play Bigger Economic Role, Says World Bank

        low and should be increased, preferably through performance-Universities in East Asia aren't giving their countries the economic boost they should because of educational and research shortcomings, concludes a report released today by the World Bank. In Putting Higher Education to Work: Skills and Research for Growth in East Asia, a team of bank experts says reforms and better funding could position universities and postsecondary vocational schools to improve economic productivity and competitiveness particularly in the developing countries of Southeast Asia, China, and Mongolia.

        The problem stems from a number of what the report calls "disconnects." The most important is a mismatch between the advanced skills needed in the workforce and the training provided at universities and other post-secondary institutions. The team also found that university research was not contributing to the technological advancement of industry and commerce. Other gaps include a lack of interaction between universities and national research institutes and inconsistent secondary schooling.

        Universities are now operating in isolation, the authors argue, instead of as part of an integrated system designed to meet strategic needs. Specific recommendations start with increasing funding for higher education and encouraging more students to go beyond secondary schools—particularly in science, technology, engineering, and math—by providing scholarships and loans. The report notes that with the exception of several more advanced countries—Korea, Japan, and China—spending on R&D as a share of GDP is relatively based funding such as competitively awarded grants. And few of these countries have university technology licensing efforts, public-private matching research funding programs, or other schemes to forge university-industry ties. The team also concludes that most of the region's universities would benef t from better management and governance and greater autonomy.

        For most of these challenges, the report provides examples of best practices drawn from within the region. "We don't want to preach" to educational and government leaders, James Adams, World Bank's regional vice president, said at the report's launch today in Tokyo. Rather, the goal is to provide comparative information for decision-makers to work with.

        世界銀行報告稱東亞各大學應發(fā)揮更大經濟作用的提升做出貢獻。其它因素則包括大學與國家科研機構之間缺乏交流,以及中學教育與大學教育脫節(jié)等。

        世界銀行今日發(fā)布報告稱,由于在教育和科研方面存在缺陷,東亞的大學在推動本國經濟增長的進程中沒能起到它們應起的作用。

        該報告分析了造成此現(xiàn)象的原因,其中最重要的是職工對高級技能的需求與高校所提供的培訓不匹配。此外,研究小組還發(fā)現(xiàn)大學研究并沒有為工業(yè)和商業(yè)技術

        在這份名為《高等教育的實際應用:東亞發(fā)展所需要的技術與科研》的報告中,研究小組表示,對于許多國家——特別是東南亞發(fā)展中國家、中國以及蒙古而言,對高校進行改革并提供更多資助,能使其在提高經濟生產力和競爭力方面發(fā)揮積極作用。

        該報告建議加大對高等教育的資金投入,并且提供獎學金和助學貸款以鼓勵更多學生接受高等教育——尤其是在科技、工程和數(shù)學領域。報告還指出,除韓國、日本和中國等較發(fā)達國家之外,其他東亞國家在科研發(fā)展領域的投入較少、所占國內生產總值的比重相對較低,所以應當加大投入,最好能以學術表現(xiàn)作為經費資助的基準,通過提供競爭性獎勵等方式實現(xiàn)。報告還總結認為,一套好的管理制度以及更多自主權,將有利于大多數(shù)區(qū)域性大學的發(fā)展。

        IBM Exhibit Visualizes Today's Urban Problems--and Potential Solutions

        At first glance the mammoth screen running down a former parking ramp at Lincoln Center looks like something on loan from Times Square, about a dozen blocks to the south. But this 37.5- by 4.3-meter digital data-visualization wall, parked in the heart of Manhattan, is offering much more than enticements to buy snacks or the latest cologne.

        Watch the animated screen a little longer, though, and you will learn something—about the city's largely untapped potential to collect solar energy, the amount of water from New York State's reservoirs wasted before it ever reaches urban residents, and the patterns in traffic and air quality that change hourly. You are seeing data that have been harvested by IBM from 100sensors throughout the city, analyzed for patterns and rendered into visualizations to create a more complete picture of the city's oft-ignored problems and potential solutions.

        "Think," a free exhibit on display at Lincoln Center through October 23, consists of three parts: At the lower end of the ramp, visitors move past the digital wall into a small theater f lled with 20massive video columns, each 2.4meters tall and 1.2meters wide. The columns are covered front and back by video screens that, when dark, resemble the primordial monolith from 2001: A Space Odyssey. They are arranged in clusters that immerse the audience for a 10-minute film highlighting scientific and technological progress in areas including space exploration, personalized medicine, traff c management and agriculture around the world. At the conclusion of the f lm, all 40video screens convert into large interactive touch panels. This lets the audience drill down on different topics via maps, timelines and images.

        View a slide show of IBM's Think exhibit.

        As visitors leave the theater they can see the f nal part of the exhibit—a timeline of key IBM milestones from the past century. Starting with the events leading up to Thomas J. Watson's founding of the Computing-Tabulating-Recording Co. in June 1911from the merger of four firms to the company's name change to International Business Machines in 1924all the way through the recent success of the company's Watson artif cial intelligence program on the game show Jeopardy!.

        Think is one of several ways IBM is celebrating its centennial anniversary this year. The exhibit however, is curiously light on advertising for "Big Blue"—as the company was previously nicknamed—and focuses more on what the company's technology is doing behind the scenes to address health care, resource conservation, food production and other 21st-century concerns. Short interactive videos in the exhibit's theater feature IBM researchers such as David Ferrucci (who led the development of Watson) as well as scientists such as Howard-Yana Shapiro, global director of plant science and external research at Mars Inc.

        "We wanted to do something that would be open to the public," says IBM's Lee Green, vice president of brand experience and strategic design. "IBM hasn't done anything like this since probably 1964when Charles and Ray Eames designed the IBM exhibition at the World's Fair in Flushing Meadows, New York." That exhibit, much less subtle, featured a dome resembling a company innovation, the electric typewriter ball, albeit with only the letters I, B and M.

        "What they did so well was take the complexity of math, science and technology and simplif ed it," Green says. "We wanted to do the same thing, [telling] stories about what it is possible to achieve today through science and technology." IBM plans to tour the exhibit to science museums and educational institutions when it completes its stay at Lincoln Center.

        New form of superhard carbon observed

        Carbon is the fourth-most-abundant element in the universe and takes on a wide variety of forms, called allotropes, including diamond and graphite. Scientists at Carnegie's Geophysical Laboratory are part of a team that has discovered a new form of carbon, which is capable of withstanding extreme pressure stresses that were previously observed only in diamond. This breakthrough discovery will be published in Physical Review Letters.

        The team was led by Stanford's Wendy L. Mao and her graduate student Yu Lin and includes Carnegie's Hokwang (Dave) Mao, Li Zhang, Paul Chow, Yuming Xiao, Maria Baldini, and Jinfu Shu. The experiment started with a form of carbon called glassy carbon, which was first synthesized in the 1950s, and was found to combine desirable properties of glasses and ceramics with those of graphite. The team created the new carbon allotrope by compressing glassy carbon to above 400,000times normal atmospheric pressure.

        This new carbon form was capable of withstanding1.3 million times normal atmospheric pressure in one direction while confinedu n d e r a p r e s s u r e o f600,000 times atmosphericlevels in other directions.N o s u b s t a n c e o t h e rthan diamond h a s beenobserved to withstand thistype o f p ressure s t re s s,indicating t h a t t h e newc a r b o n a l l o t rope m u s tindeed be very strong.

        However, unlikediamond and other cry stalline for msofcarbon, the structure of this new material is not organized in repeating atomic units. It is an amorphous material, meaning that its structure l a c k s t h e l o n g-r a n g e order of cr ystals. This amorphous, superhard carbon allotrope would have a potential advantage over diamond if its hardness turns out to be isotropic-that is, having hardness that is equally strong in all direwcions. In contrast, diamond's hardness is highly dependent upon the direction in which the crystal is oriented.

        "These findings open up possibilities for potential applications, including super hard anvils for high-pressure research and could lead to new classes of ultradense and strong materials," said Russell Hemley, director of Carnegie's Geophysical Laboratory.

        IBM推出網游CityOne直指城市問題

        IBM周一推出了一款名為“CityOne”的網絡游戲,希望通過該游戲讓玩家體驗當前城市所面臨的一些問題,并啟發(fā)玩家尋求解決問題的方法。最終,IBM希望通過該款游戲來刺激公司的服務和軟件營收。

        IBM軟件業(yè)務副總裁南希皮爾森(Nancy Pearson)稱,用戶可以選擇四大行業(yè):銀行、零售、水和能源,然后試圖解決相關問題。例如,監(jiān)控城市的水質量,或者是能源的供應情況等。

        皮爾森稱,該游戲可提升人們對IBM新服務的意識和銷售額。當前,IBM正在推行智慧地球(Smarter Planet)計劃,從而幫助企業(yè)和政府部門利用數(shù)字技術更好地進行決策。IBM此前曾表示,到2015年該項技術可給IBM帶來100億美元的銷售額。

        從周一起,用戶可免費下載該款游戲。目前,已經有7000多人注冊下載,其中包括大學、政府和企業(yè)會員。南希稱,如果有任何問題,用戶可以通過互聯(lián)網與IBM代表進行交流。

        美研發(fā)出非結晶新型碳結構材料——應付超強壓力的能力可能超過金剛石

        據(jù)美國物理學家組織網10月11日報道,碳是宇宙中儲量占第四的一種元素,其有幾種同素異形體,最常見的兩種單質是高硬度的金剛石和柔軟滑膩的石墨?,F(xiàn)在,美國科學家們制造出了一種新形式的碳,其應付超強壓力的能力讓金剛石“自愧弗如”。該突破性發(fā)現(xiàn)將發(fā)表于《物理評論快報》雜志。

        斯坦福大學的毛溫迪(音譯)和其研究生林宇(音譯)領導的科研團隊與卡內基研究所地球物理實驗室的科學家們共同做出了這項發(fā)現(xiàn)。他們讓碳的一種——玻璃碳承受40萬倍的大氣壓力,制造出了這種新的碳的同素異形體。玻璃碳于上世紀50年代才被首次合成,其兼具玻璃、陶瓷和石墨烯的一些特質,應用范圍很廣。

        科學家們發(fā)現(xiàn),新形式的碳在一個方向上能經受130萬倍的大氣壓力,在其他方向上能承受60萬倍的大氣壓力。除了金剛石之外,沒有其他物質能承受如此大的壓力,這表明,這種新的碳的同素異形體的確很堅硬。

        然而,與金剛石和其他形式的碳晶體不同的是,這種新材料是一種非結晶的物質,這意味著它的結構缺乏晶體的長距離有序性。

        如果這種非結晶的、超硬的碳的同素異形體各個方向的硬度一樣的話,其潛能優(yōu)勢比金剛石還強。金剛石的硬度主要取決于晶體的取向。

        卡內基研究所地球物理實驗室的主任羅素·赫姆利說:“最新發(fā)現(xiàn)將有很多應用領域??茖W家們或能據(jù)此制造出高壓研究所需要的超硬鐵砧以及其他超致密、超硬的新材料。”

        猜你喜歡
        研究
        FMS與YBT相關性的實證研究
        2020年國內翻譯研究述評
        遼代千人邑研究述論
        視錯覺在平面設計中的應用與研究
        科技傳播(2019年22期)2020-01-14 03:06:54
        關于遼朝“一國兩制”研究的回顧與思考
        EMA伺服控制系統(tǒng)研究
        基于聲、光、磁、觸摸多功能控制的研究
        電子制作(2018年11期)2018-08-04 03:26:04
        新版C-NCAP側面碰撞假人損傷研究
        關于反傾銷會計研究的思考
        焊接膜層脫落的攻關研究
        電子制作(2017年23期)2017-02-02 07:17:19
        久久伊人久久伊人久久| 粉嫩高中生无码视频在线观看| 日本一区二区三区在线观看免费| 日本系列有码字幕中文字幕| 亚洲乱亚洲乱妇无码麻豆| 精品国产v无码大片在线观看| 一本色道无码道在线观看| 天美麻花果冻视频大全英文版| 亚洲在战AV极品无码| 亚洲乱妇熟女爽到高潮视频高清| 岛国av无码免费无禁网站| 国产精品对白交换视频| 中文国产成人精品久久一区| 日本一区二区高清精品| 日本熟妇色xxxxx日本妇| 77777亚洲午夜久久多人| 免費一级欧美精品| 深夜一区二区三区视频在线观看| 精品久久久无码人妻中文字幕豆芽| 白嫩少妇激情无码| 最近亚洲精品中文字幕| 国产三级黄色免费网站| 色一情一区二区三区四区| 亚洲欧美中文在线观看4| 免费看男女啪啪的视频网站| 国产av无码专区亚洲av果冻传媒| 67194熟妇在线永久免费观看| 日韩av一区二区毛片| 中文字幕日韩高清乱码| 亚洲愉拍99热成人精品热久久| 久久精品中文字幕第23页| 日韩精品免费一区二区中文字幕| 成人影院在线视频免费观看| 无码粉嫩虎白一线天在线观看| 国产成人精品免费视频大全| 91青青草在线观看视频| 久久久极品少妇刺激呻吟网站| 亚洲av永久无码精品一区二区| 甲状腺囊实性结节三级| 成人久久精品人妻一区二区三区| 亚洲av无码一区二区三区天堂古代 |