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1.
Understanding the mineralogy of the Earth''s interior is a prerequisite for unravelling the evolution and dynamics of our planet. Here, we conducted high pressure-temperature experiments mimicking the conditions of the deep lower mantle (DLM, 1800–2890 km in depth) and observed surprising mineralogical transformations in the presence of water. Ferropericlase, (Mg, Fe)O, which is the most abundant oxide mineral in Earth, reacts with H2O to form a previously unknown (Mg, Fe)O2Hx (x ≤ 1) phase. The (Mg, Fe)O2Hx has a pyrite structure and it coexists with the dominant silicate phases, bridgmanite and post-perovskite. Depending on Mg content and geotherm temperatures, the transformation may occur at 1800 km for (Mg0.6Fe0.4)O or beyond 2300 km for (Mg0.7Fe0.3)O. The (Mg, Fe)O2Hx is an oxygen excess phase that stores an excessive amount of oxygen beyond the charge balance of maximum cation valences (Mg2+, Fe3+ and H+). This important phase has a number of far-reaching implications including extreme redox inhomogeneity, deep-oxygen reservoirs in the DLM and an internal source for modulating oxygen in the atmosphere.  相似文献   

2.
减少温室气体排放、遏制全球气温上升,努力实现碳中和目标是人类面对气候变化危机的主动作为和共同追求。碳中和是涉及多学科多领域的庞大系统工程,实现碳中和目标需要坚实的理论基础和科学方法的指导,碳中和学应运而生。碳中和学的理论内涵包含两个“动态平衡”——全球碳排放与碳吸收之间的动态平衡、人类发展与自然环境之间的动态平衡;技术内涵包括人类生产生活引起的二氧化碳排放、捕集、利用、封存和移除的全过程及相关的技术体系。能源消费结构从以化石能源为主向以新能源为主的转型,世界能源生产与消费结构将由当前煤炭、石油、天然气和新能源的“四分天下”,向以新能源为主的“三小一大”新格局发生根本性转变;在此过程中,需构建煤炭、石油、天然气、新能源多种能源协同发展。中国能源生产与消费结构,也将从当前以煤炭能源为主的“一大三小”,向未来以新能源为主的“三小一大”格局发生革命性转变;新能源将主导我国能源生产与消费结构转型,最终将力争实现以新能源为主体的“能源独立”。但在能源发展中,始终把能源转型与能源安全放在同等重要位置。发展新能源是实现碳中和社会、建设绿色宜居地球的关键。碳中和下新能源是世界能源转型的方向、能源科技创新...  相似文献   

3.
The Chinese lunar probe Chang''e-4 (CE-4) landed in the Von Kármán crater within the South Pole–Aitken (SPA) basin on the far-side of the Moon on 3 January 2019. Following this, the moon rover Yutu-2 separated from the CE-4 lander and started its travels and exploration on the far-side of the Moon. Before this landing, humans had remotely observed the far-side of the Moon with lunar satellites. However, it was the first time that a man-made spacecraft had landed there and actually left behind wheel prints belonging to humanity.Since China''s Lunar Exploration Project (CLEP), or Chang''e Project, started in 2004, China has accomplished the first two steps of its three-step plan of ‘Orbiting, Landing and Returning’. CE-3 and CE-4 landed successfully on the near-side and far-side of the Moon, respectively. In the near future, CE-5 will land again on the near-side of the Moon and take lunar rock and soil samples back to Earth, thus completing the three-step plan of CLEP. In April 2019, National Science Review (NSR) interviewed three key figures of CLEP: CLEP Chief Engineer Weiren Wu (), the first CLEP Chief Scientist and CLEP senior consultant Ziyuan Ouyang (), and CLEP third phase Vice-Chief Engineer, CE-4 Ground Research and Application System Director Chunlai Li (). They talked about the scientific expectations and future plans of China''s lunar and deep space exploration.  相似文献   

4.
大数据是知识经济时代的战略高地,是国家和全球的新型战略资源。作为思维的革命性创新,大数据为科学研究带来了新的方法论。第六届中德前沿探索圆桌会议以"自然科学与人文科学大数据"为主题,在"生物医药大数据"、"物理、化学与地球科学领域大数据"、"人文与社会科学领域大数据"和"大数据处理技术与方法"4个领域进行研讨,总结了大数据对于科学发现的重要作用、意义以及面临的重大问题,形成了关于发展科学大数据研究的相关建议。  相似文献   

5.
王赤 《中国科学院院刊》2022,37(8):1050-1065
空间科学是依托航天器平台研究宏观和微观世界的前沿交叉学科，自20世纪60年代以来在基础科学前沿催生了诸多诺贝尔奖级的重大发现和原创科学成果，突破了人类对自然世界的认知边界，不断拓展人类知识图谱。进入21世纪，在新一轮科技革命孕育爆发之际，空间科学也进入了革命性突破的新时代。文章回顾了近10年来国际空间科学重大进展，结合世界空间科学前沿发展态势及主要航天国家和地区空间科学任务的未来规划布局，对未来10—15年空间科学的可能突破领域进行了研判和分析，指出基于重大科学目标的系列空间科学任务，极端条件下的物理规律、中低频引力波、宇宙黑暗时代和黎明时代、太阳活动爆发机制、日地系统多圈层耦合、太阳系地外生命指征、系外行星探寻等学科前沿有望取得重大科学进展。我国正在加快建设航天强国和科技强国，空间科学领域正在奋起直追，围绕极端宇宙、时空涟漪、日地全景和宜居行星等科学主题开展前沿探索，有望在这一轮探索宇宙奥秘的世界竞技舞台上取得优异成绩，贡献中国智慧、作出中国贡献。  相似文献   

6.
A broad range of organisms, from prokaryotes to higher animals, have the ability to sense and utilize Earth''s geomagnetic field—a behavior known as magnetoreception. Although our knowledge of the physiological mechanisms of magnetoreception has increased substantially over recent decades, the origin of this behavior remains a fundamental question in evolutionary biology. Despite this, there is growing evidence that magnetic iron mineral biosynthesis by prokaryotes may represent the earliest form of biogenic magnetic sensors on Earth. Here, we integrate new data from microbiology, geology and nanotechnology, and propose that initial biomineralization of intracellular iron nanoparticles in early life evolved as a mechanism for mitigating the toxicity of reactive oxygen species (ROS), as ultraviolet radiation and free-iron-generated ROS would have been a major environmental challenge for life on early Earth. This iron-based system could have later been co-opted as a magnetic sensor for magnetoreception in microorganisms, suggesting an origin of microbial magnetoreception as the result of the evolutionary process of exaptation.  相似文献   

7.
文章介绍了太阳系和太阳系外行星冰冻圈。太阳系各行星和卫星的表面温度差异很大,它们的冰冻圈发育各不相同。水星和月球的两极陨石坑的永久阴影区中可能有水冰存在。金星太热,表面既没有液态水,也不可能有水冰存在。火星两极存在永久性冰帽,包括水冰和干冰(固态CO2)。在太阳系雪线之外,存在很多冰卫星和富含水的矮行星,它们的主要是由水冰组成的;在极低的温度下,水冰甚至比地球上的岩石还要坚硬,并成为这些星体的壳层。除了水冰,其他易挥发组分如CO2、CH4、N2、CO等在极低温度下都会凝固为冰,形成不同于水冰的冰冻圈。因此,行星冰冻圈具有与地球冰冻圈迥然不同的丰富多样性。对行星冰冻圈的研究有助于我们扩大视野,更深入地理解地球冰冻圈,也将有助于我们理解太阳系的形成、地球水分的来源、地球深时古气候环境和生命演化,以及开展未来的系外生命探测。  相似文献   

8.
Dick SJ 《Endeavour》2006,30(2):71-75
Almost from its beginnings in 1958, the National Aeronautics and Space Administration (NASA) set up a life-science program. Because one of the priorities of the organization is to search for life beyond Earth, NASA began designing spacecraft to unravel the mysteries of Mars. The effort to search for life on Mars culminated in the landing of two Viking spacecraft on the surface of the planet in 1976. Although the biology experiments conducted as part of these missions provided some evidence for the possibility of life, the scientific consensus was that they drew a blank. In 1996, however, the 'Mars rock' rekindled interest in life in our solar system. The discovery of an ocean on the Jovian moon Europa, of organic molecules on the Saturnian moon Titan and persuasive evidence that water once flowed on Mars suggests that the solar system is still of considerable exobiological interest. In addition, since 1995 approximately 175 planets have been found beyond our solar system. Although these discoveries are gas giants, NASA spacecraft might soon detect Earth-sized planets. The search for life in the universe continues.  相似文献   

9.
About every 26 months, the distance between Earth and Mars reaches a minimum, and that is the best time window for Mars exploration from Earth. In July 2020, three spacecraft started their journey to Mars: the Hope orbiter of the United Arab Emirates, the Tianwen-1 mission of China and the Perseverance rover of the United States’ National Aeronautics and Space Administration (NASA). If all go well, these spacecraft will reach Martian orbit in February 2021 and start their scientific observations.Tianwen-1 is China''s first mission to Mars. It includes an orbiter, a lander and a rover. It carries 13 scientific payloads and will investigate the topography, soil composition, water-ice distribution, internal structure, atmospheric environment and physical fields (electromagnetic and gravitational) of Mars. In this interview, we talked with the mission''s Chief Scientist Yongxin Pan (潘永信) and Scientific Payload Sub-System Director Chi Wang (王赤) about this scientific mission and China''s future plans for Mars exploration.  相似文献   

10.
行星地质学是从天文学和地质学中发展形成,借鉴传统地质学的方法和手段研究太阳系中行星、卫星、小行星、彗星和行星环等固态天体的形成和演化过程的一门交叉学科。其研究领域随着太阳系探测的发展而不断拓展,涵盖行星固体圈、行星表面环境、行星资源以及生物或适生环境演化等多个方面。行星地质学与月球和深空工程探测相辅相成,工程探测为学科的发展提供了重要的研究基础,而行星地质学的新发现又能很好地促进工程探测的实施。但目前我国行星地质学的发展还相对落后,在研究平台和研究队伍上仍存在很多短板。行星地质学是跳出地球看地球,进一步比较、拓展、深化和推动地球科学的创新发展。随着国家深空探测科技战略的深入推进,行星地质学研究的制约愈发明显,需及早布局、大力发展,以满足学科发展和工程探测的迫切需要。  相似文献   

11.
地球科学是以地球各圈层相互作用及其资源与环境效应为研究对象，多学科交叉融合的一门科学。地球科学既研究过去，阐述地球演化历史，又面向未来，为人类可持续发展提供解决方案，是一门既能拓展人类知识前沿又能服务于人类社会经济发展的综合性、系统性的科学。文章在梳理国际地球科学发展趋势和总结我国地球科学发展现状与科技资助情况的基础上，提出我国地球科学发展应从系统科学和国家需求的视角部署未来发展方向和研究计划。从地球系统整体出发，关注地球系统各圈层、各要素之间的相互作用及其对人类社会经济发展的影响。以“四个面向”引领地球科学领域研究的发展方向，开展有组织的重大科学研究，完善科技资助与评价机制，使研究成果更好地服务于国家重大战略需求。  相似文献   

12.
“奋斗者”号载人潜水器的成功研制及良好应用显著提升了我国载人深潜的装备研发能力和自主创新水平，为加快建设海洋强国作出了突出贡献。21世纪是“海洋的世纪”，海洋蕴含的丰富资源是支持人类持续发展的宝贵财富。开发和利用海洋资源成为各国发展的必然趋势，但是面向深海的资源开发需要更加专业化的科考装备。为此，文章在回顾世界各国载人潜水器发展历程的基础上，对目前世界上现有的大深度载人潜水器的工作性能和关键技术的发展进行了总结，分析了当前我国载人潜水器的发展现状及其关键核心技术，并提出未来发展建议，以期为加快建设世界海洋科技强国提供管窥之见。  相似文献   

13.
联合国《改变我们的世界:2030年可持续发展议程》是各国实现经济、社会和环境共同发展的重要指南。当前,该议程的17个可持续发展目标(SDGs)的监测和评价已取得重要进展,但各SDGs间相互作用,特别是SDGs间的协同和权衡关系的认知仍较有限。文章首先从全部目标关系的综合分析、典型多目标关系分析、单目标内子指标间的关系3个方面描述了当前SDGs协同与权衡的研究进展和主要发现;并针对研究中的数据瓶颈问题,剖析了地球大数据支撑多目标协同和权衡的思路及典型案例;在此基础上,对地球大数据促进SDGs协同和权衡研究进行了展望。研究表明,地球大数据在提升SDG指标数据一致性、透明性、时效性和准确性等方面能够发挥重要作用,可以改进前期基于专家知识或统计数据等方法的不足,为提升多目标协同和权衡研究的定量水平提供重要数据支撑。最后,应对SDGs权衡的挑战,提出了完善地球大数据支撑SDGs协同与权衡的方法体系并构建模拟与预警平台、加强不同领域和主体的合作、强化技术创新推动等建议。  相似文献   

14.
Current barriers hindering data-driven discoveries in deep-time Earth (DE) include: substantial volumes of DE data are not digitized; many DE databases do not adhere to FAIR (findable, accessible, interoperable and reusable) principles; we lack a systematic knowledge graph for DE; existing DE databases are geographically heterogeneous; a significant fraction of DE data is not in open-access formats; tailored tools are needed. These challenges motivate the Deep-Time Digital Earth (DDE) program initiated by the International Union of Geological Sciences and developed in cooperation with national geological surveys, professional associations, academic institutions and scientists around the world. DDE’s mission is to build on previous research to develop a systematic DE knowledge graph, a FAIR data infrastructure that links existing databases and makes dark data visible, and tailored tools for DE data, which are universally accessible. DDE aims to harmonize DE data, share global geoscience knowledge and facilitate data-driven discovery in the understanding of Earth''s evolution.  相似文献   

15.
The National Natural Science Foundation of China (NSFC) is the major funding agency for China''s basic research in natural science. The total budget for NSFC was 26.7 billion Yuan (RMB) in 2017, accounting for 27% of China''s total investment in basic research. In the past decades, continuous increases in the National Natural Science Fund and other funding programs provided strong support for the rapid growth in China''s science and technology (S&T). In the second half of 2018, NSFC unveiled a deep reform plan that aims to build a fair, efficient and standardized new funding system that meets the demands of excellence in science in the twenty-first century in 5–10 years. Why did NSFC propose this reform? What are the major tasks of this reform? And how would NSFC implement this reform? All-in-all, this reform would not only have profound effect on S&T in China but also matters the world for the global collaborative efforts for the science. Recently, National Science Review had an exclusive interview with Jinghai Li, President of NSFC and Academician of the Chinese Academy of Sciences, to learn his views and perspectives of the future of NSFC.  相似文献   

16.
This paper contributes to the scarce empirical literature on the impact of foreign ownership on human capital intensity. New evidence is provided, based on a comprehensive, large-scale survey of technology-based firms located in Portugal. The key findings are that: (1) foreign ownership directly (and significantly) impacts a firm's general human capital (education); (2) foreign ownership indirectly (and significantly) impacts a firm's specific human capital (skills); (3) the total impact of foreign ownership on a firm's human capital intensity is higher for education- (general) than for skills- (specific) related human capital intensity. Giving the critical importance of both FDI and human capital development for an ‘intermediate’ economy like Portugal (lagging behind in terms of human capital stock, and seeming to have lost part of its attractiveness as an FDI location), the paper discusses related policy implications. It is believed that our results and conclusions may be useful for other countries facing similar challenges.  相似文献   

17.
从深空探测大国迈向行星科学强国   总被引：5，自引：2，他引：3       下载免费PDF全文
自伽利略1609年将望远镜指向星空迄今,已逾400年。1959年苏联"月球2号"首次抵达月球,开启深空探测时代。1969年美国"阿波罗11号"首次载人登月,催生建立行星科学。纵观人类深空探测60年,先后出现两次探测热潮、两个深空探测大国(美国、苏联)。苏联领先又衰落,仅留给历史一个深空探测大国的背影,而美国成功转型为深空探测强国,至今在世界行星科学最前沿领航。探索浩瀚宇宙,是全人类的共同梦想。作为正在发展中的深空探测大国,我国应该怎样立足国情,走出一条有中国特色的行星科学强国之路?文章参照历史,梳理现状,畅想未来,给出我们的思考:大力培养行星科学人才,尽快实现科学引领深空探测。  相似文献   

18.
Sentiment analysis concerns the study of opinions expressed in a text. Due to the huge amount of reviews, sentiment analysis plays a basic role to extract significant information and overall sentiment orientation of reviews. In this paper, we present a deep-learning-based method to classify a user's opinion expressed in reviews (called RNSA).To the best of our knowledge, a deep learning-based method in which a unified feature set which is representative of word embedding, sentiment knowledge, sentiment shifter rules, statistical and linguistic knowledge, has not been thoroughly studied for a sentiment analysis. The RNSA employs the Recurrent Neural Network (RNN) which is composed by Long Short-Term Memory (LSTM) to take advantage of sequential processing and overcome several flaws in traditional methods, where order and information about the word are vanished. Furthermore, it uses sentiment knowledge, sentiment shifter rules and multiple strategies to overcome the following drawbacks: words with similar semantic context but opposite sentiment polarity; contextual polarity; sentence types; word coverage limit of an individual lexicon; word sense variations. To verify the effectiveness of our work, we conduct sentence-level sentiment classification on large-scale review datasets. We obtained encouraging result. Experimental results show that (1) feature vectors in terms of (a) statistical, linguistic and sentiment knowledge, (b) sentiment shifter rules and (c) word-embedding can improve the classification accuracy of sentence-level sentiment analysis; (2) our method that learns from this unified feature set can obtain significant performance than one that learns from a feature subset; (3) our neural model yields superior performance improvements in comparison with other well-known approaches in the literature.  相似文献   

19.
The University of Surrey (referred to as Surrey hereafter) is one of the renowned universities in the UK that was established on 9 September 1966 with the grant of its Royal Charter and its roots go back to Battersea Polytechnic Institute, founded in 1891. Surrey is the research hub of small satellites, mobile telecommunication and artificial intelligence in Europe. In 2016, Surrey was named as ‘University of the Year’ in the UK and, in February 2018, Surrey won the Queen''s Anniversary Prize for Higher and Further Education (Surrey''s fourth award)—the highest national award for the UK universities, in recognition of the outstanding contribution of Surrey to nutrition and health.The president and vice chancellor of Surrey, Professor Max Lu, took this position in 2016 and is also the first scholar of Chinese origin to be the leader of a British university. Before he joined Surrey, he was the provost and senior vice president at the University of Queensland in Australia. Professor Lu is not only a talented leader in education field, but also a distinguished scientist in materials chemistry and nanotechnology area. He has been honored with numerous awards, including the Orica Award, RK Murphy Medal, China International Science and Technology Award and Medal of the Order of Australia, etc. He has been also appointed to the Prime Minister''s Council for Science and Technology and the Board of UK Research and Innovation, etc. The rich experience and open-mindedness lead to his profound insights into higher education around the world. Lately elected as a fellow of Royal Academy of Engineering (RAEng) and foreign member of the Chinese Academy of Sciences, Professor Lu shared his broad and deep perspectives on higher education with National Science Review during his travel in Beijing.  相似文献   

20.
This paper presents a solution for a semi-infinite plate containing a deep semi-elleptic edge notch when the plate is under a uniaxial tension parallel to the edge. The solution is a direct solution composed of three parts, which is developed from Howland's method of successive approximations through two significant modifications. It is found that the present solution is more adaptable to numerical computation with regard to the depth ratio of the notch than other solutions known to exist. Numerical values of the stress concentration are given for a depth ratio up to 10.  相似文献   

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