共查询到20条相似文献，搜索用时 671 毫秒
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《中国科学院院刊(英文版)》2014,(1):35-37
<正>Graphene triggered a global research upsurge since the researcher in the University of Manchester exfoliated it from graphite through"scotch tape"method in 2004.Graphene is regarded as a new potential material in the"Postsilicon Era"for making nano-sized transistors and circuits.Breakthroughs in this regard ensued in just a few years.Many kinds of products made by graphene are available now,and industrialization of graphene is underway.1.Major ST connotation and significance Graphene is a kind of new material composed by carbon atoms through sp2 hybrid orbital,which is featured 相似文献
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Jean-dedieu Weyepe 《中国科技纵横》2014,(15):11-11
Air data and inertial reference system （ADIRS） is one of the complex sub-system in the aircraft navigation system and it plays an important role into the flight safety of the aircraft. This paper propose an optimize neural network algorithm which is a combination of neural network and ant colony algorithm to improve efficiency of maintenance engineer job task. 相似文献
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网络环境下的信息组织研究 总被引：26，自引：1，他引：26
On the basis of the theory and method of conventional literature organization, this paper expounds the development of the theory and method of information organization under the network environment, and discusses how the method of conventional literature organization suits the network information organization and how to construct new methods of information organization according to the characteristics of network information. 相似文献
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In the 1970s the development of high-resolution electron microscopy (HREM) provided a new approach to structure determination for minute crystals, which is thoroughly different from the diffraction methods.However, the previous method of trial and error has its own limits, such as some preliminary structural information must be known in advance; the crystals must be sufficient strong under the electron beam irradiation;and not all atoms can be seen in the image. Two ideas were proposed to initiate the present research project:one is to transform an arbitrary image into the crystal structure map, and the other is to enhance the image resolution by combining the information contained in the image and the corresponding electron diffraction pattern. These ideas have been realized via the combination of electron microscopy and diffraction crystallography. 相似文献
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《中国科学院院刊(英文版)》2014,(1):75-77
<正>1.The global pharmaceutical market has entered a new round of adjustment The global pharmaceutical market keeps growing,but it faces problems like a decreasing ratio of RD investment to new drug output and the expiration of patented drugs.It is shifting to emerging countries with an increasing proportion of biotech drugs,and a new round of adjustment has been kicked off.Over the years,the pharmaceutical industry has been developing rapidly and persistently to become the fastest growing high-tech sector.However,the whole industry is facing a decreasing ratio of RD investment to new drug output.The RD spending of AstraZeneca,GlaxoSmithKline,Sanof i,Roche and Pf izer kept rising in the past 15 years but bore few fruits,and the output is signif icantly disproportional to the input.Besides,the expiration of a large number of 相似文献
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ZHANG Min XIA Jun & HONG Cheng Huai River Water Resources Commission Ministry of Water Resources Bengbu Anhui China State 《中国科学院院刊(英文版)》2012,(1):40-47
This paper addresses the change of the river-lake relationship in the Huai River and its causes due to environmental change and human activities. A preliminary analysis is made from three aspects: (1) the natural geographical change particularly captured by the Yellow River, (2) water conservancy project construction, and (3) socioeconomic development in the Huai River Basin. Key problems of changes in this river-lake relationship and the Huai River flood control are tackled, involving flood control and disaster alleviation ability of the Basin, engineering and non-engineering measurements applied to flood control and disaster mitigation, and water governance for adaptive management. Research shows that the Huai River is a rather complex one due to its complex geography with a hybrid wet and dry climate zoon, and higher population density. With the alternation of the river-lake relationship and socioeconomic development in the region, new problems keep arising, imposing new requirements on its sustainable water management. Thus, understanding the Huai River is a long and gradually improving process. Its future planning should keep absorbing new achievements of science and technology development, employing new technologies and methods, and gradually deepening our understanding of its fundamental principles. Water governance and adaptive water management will be new challenges and opportunities for the Basin in its river system change and flood control. 相似文献
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Innovation, both at past and in the future, is always an everlasting topic in the world, and there is no exception in the educational field. Knowledge economy is featured in the 21st century, while the key of which is the continuous innovation of knowledge. Thus such new talents, with innovation mind and ability, are badly needed. 相似文献
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《中国科学院院刊(英文版)》2014,(1):68-70
<正>Computer science and industry currently is facing many challenges,among which the most essential one is that the traditional computer industry is losing its development vigor.To reverse this trend,researchers have proposed a new perspective:a new paradigm named computing for the masses.Computing for the masses is much more than 相似文献
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武器装备采办的知识管理模式探索 总被引：1，自引：0，他引：1
The paper applies the theory and method of knowledge management to the field of defense acquisition,and proposes a new idea of knowledge-based defense acquisition management model for this field. 相似文献
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《中国科学院院刊(英文版)》2004,18(3):141-141
Isomorphism is a universal phenomenon, which helps us gain more knowledge about nature.Thanks to the phenomenon,for example, many new species and genera have been identified in plant and animal taxonomy. In geology,however, the complete isomorphous series is quite rare. Among the nearly 100 new minerals discovered over the past two decades, no report has been made on such series.It seems to be more difficult to find it out than to discover a new mineral. 相似文献
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【目的/意义】为保证叙词表术语收录的完整性,需要及时将领域出现但未收录的新术语补充收录到叙词表
中,结合候选词的时间及文档词频特征,从时间序列角度探索新术语的分布情况以指导新术语遴选是值得研究的
问题。【方法/过程】文章主要对词汇文档词频对应的时间序列进行研究,将时间序列进行词频归一化及时间等长预
处理,引入k-means聚类算法,对候选词汇进行基于时间序列趋势变化的聚类,探索术语以及非术语趋势变化的规
律,进而总结新术语应该满足的趋势变化特征。【结果/结论】通过聚类研究,总结得出新术语普遍处于增长趋势。
实证将处于增长状态的候选词汇遴选出来,经过专家判断,该方法可以有效从候选词汇中遴选出其中能补充到叙
词表中的新术语,该方法有比较高的准确率。【创新/局限】创新之处表现为叙词表新术语的遴选中同时考虑了时间
变化和文档词频因素,局限于数据处理规模,实证中只统计了论文关键词的词频数据。 相似文献
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基于聚类的词表等级关系自动识别研究 总被引：3，自引：0，他引：3
词汇等级关系的识别是自动构建叙词表的重点和难点之一.基于相似度的词聚类方法,突破了按字面聚集等级关系词汇的传统做法的局限性,能够深入语义,识别出字面上无此特点的等级关系词汇.介绍了该方法并进行测试,试验结果表明该方法具有一定可行性. 相似文献
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《汉语主题词表》是我国情报检索语言发展历史中的一个里程碑。在网络时代,《汉语主题词表》将得到新的发展和应用。文章针对《汉语主题词表》的现状,回顾了它的编制和修订历史,其作为情报语言检索工具,在信息组织中发挥了重要作用。对如何在知识组织中发挥作用,如何在网络环境下构筑适应计算机环境的新型词表,向网络环境下的词系统推进,作者提出了新的发展思路和策略方法。 相似文献
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叙词在网络环境中的应用 总被引：1，自引：1，他引：1
本文叙述了叙词在网络环境下的三种应用模式，在一些专业性的网站以及网关检索系统中用叙词直接标引和检索是非常的普遍；叙词由于其概念定义明确，有很好的词问关系的显示，叙词能在基于关键词检索的搜索引擎中实现检索式的扩展的功能；不同部门对所拥有的资料和图书馆等信息源一般所采用的不同的叙词表或采用分类法，在网络环境下，通过一种主题的途径来检索这些信息是信息情报界研究的一个热点，叙词在这方面有着重要的作用。 相似文献
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在分析分面叙词表词表结构简明、用户使用方便、大大减轻标引工作量、电脑编表速快质高、合二为一优化整体效能、多用途多功能、管理机构精简、便于集中管理等优点之后,指出了分面叙词表对编表人员能力素质要求高、编表技术难于掌握、难以推广等不足之处。并对分面叙词表与其他一些兼容途径的差异做了简要比较。 相似文献
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面向信息检索的汉语同义词自动识别和挖掘 总被引：3，自引：0，他引：3
为了提高同义词自动挖掘的效率，本文提出了从词典释义中自动识别和挖掘同义词的方法，使用超链接分析算法和模式匹配算法，从不同的角度提取同义词：第一部分是把词汇之间注释与被注释的关系看成是一种链接关系。对给定的词汇进行分析，把与给定词汇具有链接关系的所有相关词汇构造一个词汇图，图中的每一个节点代表相关词，每条弧代表了词汇之间注释与被注释的关系。利用超链接分析方法并结合PageRank算法，计算词汇的PageRank值，把PageRank值看成是体现词汇之间语义相似性的衡量指标，最后为每一个词汇生成候选同义词集，并通过一定的筛选原则和方法，推荐出最佳的同义词。第二部分是利用词汇定义模式，对词汇的释义方式进行分析，归纳总结出在词典释义中同义词出现的模式，进而利用模式匹配方法识别和挖掘同义词。此外，利用模式匹配方法对Web网页和期刊论文中的同义词也进行了挖掘测试。测试结果表明，利用模式匹配和超链接分析方法来自动识别和挖掘同义词具有可行性和实用性。 相似文献