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1.
《中国科学院院刊(英文版)》2008,22(4):201-201
Hominin fossils are the most important materials to explore human origins and evolution. Since most hominin fossils unearthed so far are incomplete, or filled with a heavy calcified matrix, it is difficult or often impossible to reconstruct the endocast in a real fossil without destroying it. Accordingly, traditional methods limit the study of human brain evolution. 相似文献
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A group of paleontologists from China, the United States and Canada have made new progress in tracking down the process of the evolution of smallsized dinosaurs and the origin of birds through intensive analysis of the fossils of a newly found dinosaur,Sinovenator, a close relative of birds. In a letter published in the Feb.14 issue of Nature, dinosaur expert Dr. Xu Xing at CAS Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) and his coworkers reveal some interesting phenomena in the process of the evolution of dinosaurs towards birds. 相似文献
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研究了采自中国东北晚三叠世羊草沟组的一种裸子植物雄球花——纤细堆囊穗。通过对新材料的研究,发现这种雄球花小孢子叶末端的裂片在形态上差异很大,这是原来没有发现的十分重要的特征。这些保存精美的化石对于纤细堆囊穗特征的阐明和修订以及物种复原很有帮助。将中国的标本与西伯利亚堆囊穗、小堆囊穗、乌尔马堆囊穗和被定为长叶拜拉的雄球花进行了比较,发现它们与纤细堆囊穗在特征上一致,故将它们处理为纤细堆囊穗的异名。修订后的纤细堆囊穗包括上面所提到的所有种。同时,也讨论了堆囊穗属可能的演化意义。它可能是银杏属的远祖,经过小孢子囊数目的减少和小孢子叶长度的缩短而演化到现在的银杏,而产自辽西早白垩世的辽宁银杏可能代表了堆囊穗和现代银杏在形态演化上的一个中间步骤。 相似文献
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Zhoukoudian (ZKD), a tiny village, is about 50 kilometers southwest of downtown Beijing. Since ancient times, it has been noted for its abundant trove of mammal fossils, as the hilly area in the vicinity is at the end of a dismembered branch of the Taihang Mountains, where they meet the North China Plain. There are a lot of well-developed and well-preserved Pleistocene sediments with valuable fossilized records in this area. Its great value for the study of human ancestry was first discovered by Western scholars in 1921. 相似文献
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《中国科学院院刊(英文版)》2005,19(2):74-75
Lichens are believed to play a pioneering role in transforming the earth surface when they appeared on land hundreds of million years ago, paving the way for the evolution of terrestrial plants and animals. But most habitats where lichens dominate,such as tundra, mountains, and deserts, have a very low chance of preserving fossils. Until recently the earliest known lichen fossils were discovered in 1995 by Thomas N.Taylor, a University of Kansas researcher, from 400 million-year old deposits in Scotland. 相似文献
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《中国科学院院刊(英文版)》2019,(4)
A key feature of the fossils found in a new Cretaceous mammal(as in the reconstructed early Cretaceous environment above) provides evidence for separation of hearing and chewing modules, an important step to the evolution of the mammalians' multi-boned middle ears. 相似文献
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Hepeng Jia 《国家科学评论(英文版)》2019,6(1):171
In recent years, Chinese scientists have achieved significant progress in paleontological discoveries and scientific studies. Series of studies published in top journals, such as Science, Nature and Proceedings of the National Academy of Sciences of the United States of America (PNAS), have astonished the world by presenting beautiful fossils that furnish robust evidence to enrich the understanding of organismic evolution, major extinctions and stratigraphy. It has been portrayed as the heyday in the paleontology of China. What is the status of the field? What factors have caused the avalanche of fossil discoveries in China? What implications can these new discoveries provide for our understanding of current evolution theories? How, given their significant contribution to the world''s paleontology scholarship, can Chinese scientists play a due leadership role in the field? At an online forum organized by the National Science Review (NSR), its associate editor-in-chief, Zhonghe Zhou, asked four scientists in the field as well as NSR executive editor-in-chief Mu-ming Poo to join the discussion. Jin Meng Paleobiologist at American Museum of Natural History Mu-ming Poo Neurobiologist at Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences Shuzhong Shen Stratigrapher at Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences Shuhai Xiao Paleobiologist and geobiologist at Virginia Polytechnic Institute and State University Zhonghe Zhou (Chair) Paleobiologist at Institute of Vertebrate Paleontology and Paleoanthropology (IVPP), Chinese Academy of Sciences 相似文献
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The fossils here described were collected from the Lai Yuan, Hebei Province in
north China. Well-preserved plant parts are cones of Pinus, identified as Pinus pro-
totabulaeformis sp. nov. The species is different from other taxa of Pinus by larger
cones and scales. The size of the cone is a reliable diagnostic character in the group:
The large cone and scale indicate rather an arid climate in Summer in the region
where the fossils are discovered.
The age of bearing-beds is considered Upper Eocene-Lower Oligocene.
Diagnosis: Cones ovate in general outline, 8.5 cm long, 4.5 cm in diameter. Seed
scales oblong, 2—2.5 cm long, 0.8—1.1 cm wide. Apophysis obviously fattened andthickned, convex, compressed rhomboid, rostrate at the apical part of seed-bract. 相似文献
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东昆仑沙松乌拉地区发现的寒武纪异源类化石,其组合为Leiosphaeridia sp.（光面球藻）、lophosphaeridium sp,（瘤面球藻）Trachysphaeridium sp.（鲛面球藻）、Heliosphaeridium sp.（射棘球藻）Pterospermella sp.（翼球藻）Brocholaminaria nigrita Ouyangetal. （黑色穴面膜片）,根据所获的疑源类化石组合,其时代应当为早寒武世.早寒武世异源类化石的发现进一步证明了早寒武世沙松乌拉组在东昆仑南坡俯冲增生杂岩带中的存在,对研究东昆仑地区中新元古代和早古生代的地质构造演化史具有重要意义. 相似文献
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基于人地关系的澜沧江流域人居环境评价 总被引：1，自引：0，他引：1
自20世纪90年代大湄公河次区域(GMS)经济合作的全面启动以来,澜沧江流域(即湄公河上游)成为世界关注的焦点。本文以澜沧江流域作为研究区,以人居环境作为研究内容,在明晰人居环境概念,建立基于人地关系的人居环境分析框架基础上,系统地构建了人居环境评价指标体系,选取澜沧江流域56个县(区、市),借助因子分析法和Arcgis空间分析,对2000年-2009年澜沧江流域人居环境时空演进展开实证分析。研究结果显示:①从空间格局上看,澜沧江流域人居环境适宜性由南至北等级递减;从时序演进上看,2000年-2009年澜沧江流域人居环境总体呈恶化趋势;②近10年来,基础设施在人居环境中的重要性逐步被经济发展因素所超越,大力发展经济,提升第三产业比重,进一步完善基础设施,成为改善人居环境的关键所在。 相似文献
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金属材料的发展与人类文明和进步息息相关。非晶合金材料是一类原子结构长程无序,具有独特优异性能的新型金属材料。近年来,非晶合金材料的研发、相关科学问题的研究、在高新技术领域的应用得到快速发展,并对金属材料的设计和研发、结构材料、绿色节能材料、磁性材料、催化材料、信息材料等领域产生深刻的影响。为此,文章在回顾非晶合金材料研究和研发历史过程的基础上,分析了当前其学科的前沿科学问题、发展方向,以及我国在该领域发展的问题、机遇和挑战,并提出相应的启示和建议,以期为加快新金属材料的发展,特别是在高新技术领域的应用提供管窥之见。 相似文献
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大企业创新投入驱动区域产业升级效应研究 总被引：1，自引：0，他引：1
利用2012—2014年的中国区域产业数据和制造业上市公司数据,采用分位数回归法,探讨大企业创新投入对地区产业升级的影响,并分析专业化集聚和市场化在其中的调节作用。研究结果表明:大企业创新投入对区域产业升级有明显的带动作用,随着产业高度的提升,创新的资本投入对产业升级的带动作用在降低,而创新的人员投入对产业升级的带动作用在提升。专业化集聚有利于大企业发挥创新带动作用,而市场化对大企业创新资本投入的产业升级带动作用表现出抑制效应。要充分发挥大企业的产业升级带动作用,关键在于营造有利于创新的制度环境,引导大企业明确其在新经济环境中的定位,构建企业间协调发展的区域产业创新环境,并充分发挥人力资本在创新中的作用。 相似文献
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空间材料科学研究是人类最有价值的空间探索事业之一。在过去的30多年里,该领域取得了巨大的进展,同时从其成功与挫折中也积累了很多经验和教训。随着空间实验机会的增加,以及更多的国家加入到空间科学研究中来,空间材料科学研究在未来20年预期会取得更大的突破。为保持在空间探索领域的竞争力,我国需要制定一部具有深刻科学洞见同时又切实可行的空间材料科学研究战略规划。 相似文献
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我国农村有机废弃物资源及沼气潜力 总被引：1，自引：0，他引：1
张无敌刘士清周斌何彩云 《资源科学》1997,19(1):67-71
我国农村每年有各类秸秆6.2×108t，除去40%用于饲料和其他工业原料外，若全部用于沼气发酵，每年可产沼气744×108m3。每年农村可有各种畜禽粪便34.781×108t（TS为20%），可产沼气1536.21×108m3。每年农村有人粪尿1.7×108t，可产沼气88.4×108t3。 相似文献
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Kjoergaard PC 《Isis; an international review devoted to the history of science and its cultural influences》2012,103(2):340-355
Fossils have been traded for centuries. Over the past two hundred years the market has developed into an organized enterprise, with fossils serving multiple functions as objects of scientific study, collectors' items, and investments. Finding fossils, digging them up or purchasing them, transporting, studying, and conserving them, and putting them on display was and still is expensive. Since the early nineteenth century, funding bodies, academic institutions and museums, philanthropists, dealers, collectors, amateurs, and professional paleontologists have constituted elaborate networks driven by collaboration, necessity, ambition, accolades, and capital to generate knowledge and produce geological artifacts, increasing our understanding of the natural world, advancing careers and institutions, and contributing to personal fortunes. The emergence of paleoanthropology as a scientific discipline around 1900 generated a scientific focus on the human story that was easy to sell. The scarcity of ancient human remains made it close to impossible for a commercial market to evolve, yet finding them required serious funding. Elaborate schemes for financing expeditions and excavations went hand in hand with individual aspirations, patronage, philanthropy, networks, and alliance building, as concession rights and access to sponsors were objects of regular political intrigues and often bitter disputes. 相似文献
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“制造强国梦、材料当先行”。关键新材料是未来高新技术产业发展的基石和先导。本文从关键新材料创新突破的演进规律、技术创新、商业化应用、战略与政策等四个方面梳理了近年来关键新材料创新突破的研究进展。研究表明,产业升级不断对关键新材料创新突破提出新的要求和挑战,而关键新材料的创新突破也会进一步推动产业升级。为此,世界各国都根据本国新材料发展情况纷纷制定关键新材料创新突破战略和政策,争夺科技制高点。然而,关键新材料具有“高技术不确定性”和“高市场不确定性”,这决定了关键新材料创新突破面临“技术创新”和“商业化应用”两大难题。未来需要加强智能制造技术经济范式变革和重点领域智能转型对关键新材料创新突破的影响、关键新材料技术创新突破的实现路径、不同类别关键新材料商业化应用模式的创新以及战略与政策的精准设计等方面的研究。 相似文献
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组织双元是中国管理理论研究的重要前沿领域,也是国际学界探究新兴经济国家管理问题的重要视阈。以CSSCI和Web of Science数据库收录的469篇中国情境组织双元研究论文为研究对象,通过文献计量和科学知识图谱分析,借助Citespace软件,揭示该领域国内外的主要学术群体、标志性文献和知识演化趋势。研究发现：国内研究者可归为双元创新、合作网络、双元领导等学术群体,国外研究者可归为复杂策略、人力资源管理、社会资本等学术群体,国内研究侧重技术创新、知识管理和国际化、信息化、高层管理实践等,国外研究突出转型经济、新兴经济的特殊情境和中国传统文化应用;焦豪、王凤彬、魏江、Cao Q、Wang CL、Lin HE、Atuahene-GimaK等的相关研究成果是标志性文献;国内外研究的热点和趋势不尽相同,国外关注人力资源实践、社会资本、并购与整合等,国内关注高管团队行为整合、知识网络、开放式创新等,当前国内外研究均进入新一轮的探索期,但国内研究表现出更强的发展潜力。提出未来的研究方向,有助于学者从世界管理理论创新的视角,深入思考中国双元问题的独特性,为服务中国企业的双元管理实践提供指导。 相似文献
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