文章运用文献计量方法,以美国科学情报研究所开发的Web of Science数据库为数据源基础,检索了有关研究影响因子的文献,并从文献量、著者、机构、核心期刊、引文等角度进行了统计和分析,以定量数据从侧面反映了影响因子这一评价期刊质量...文章运用文献计量方法,以美国科学情报研究所开发的Web of Science数据库为数据源基础,检索了有关研究影响因子的文献,并从文献量、著者、机构、核心期刊、引文等角度进行了统计和分析,以定量数据从侧面反映了影响因子这一评价期刊质量的指标在其被提出之后30余年内的发展情况。展开更多
Web网页中往往包含许多主题噪声,准确地自动抽取关键词成为技术难点。提出了一个文本对象网络模型DON,给出了对象节点的中心度概念和基于中心度的影响因子传播规则,并据此自动聚集DON中的主题社区(topic society),从而提高了模型的抗噪...Web网页中往往包含许多主题噪声,准确地自动抽取关键词成为技术难点。提出了一个文本对象网络模型DON,给出了对象节点的中心度概念和基于中心度的影响因子传播规则,并据此自动聚集DON中的主题社区(topic society),从而提高了模型的抗噪能力。提出一个基于DON的网页关键词自动抽取算法KEYDON(Keywords Extraction Algorithm Based on DON)。实验结果表明,与基于DocView模型的相应算法相比,KEYDON的准确率提高了近20%,这说明DON模型具有较强的抑制主题噪声能力。展开更多
Purpose: Communicating scientific results to the public is essential to inspire future researchers and ensure that discoveries are exploited. News stories about research are a key communication pathway for this and ha...Purpose: Communicating scientific results to the public is essential to inspire future researchers and ensure that discoveries are exploited. News stories about research are a key communication pathway for this and have been manually monitored to assess the extent of press coverage of scholarship.Design/methodology/Approach: To make larger scale studies practical, this paper introduces an automatic method to extract citations from newspaper stories to large sets of academic journals. Curated ProQuest queries were used to search for citations to 9,639 Science and3,412 Social Science Web of Science(WoS) journals from eight UK daily newspapers during2006–2015. False matches were automatically filtered out by a new program, with 94% of the remaining stories meaningfully citing research.Findings: Most Science(95%) and Social Science(94%) journals were never cited by these newspapers. Half of the cited Science journals covered medical or health-related topics,whereas 43% of the Social Sciences journals were related to psychiatry or psychology. From the citing news stories, 60% described research extensively and 53% used multiple sources,but few commented on research quality.Research Limitations: The method has only been tested in English and from the ProQuest Newspapers database.Practical implications: Others can use the new method to systematically harvest press coverage of research.Originality/value: An automatic method was introduced and tested to extract citations from newspaper stories to large sets of academic journals.展开更多
为了探究复合材料波纹腹板梁在坠撞过程中的吸能性能,对复合材料波纹腹板梁试验件进行了动态冲击压溃试验研究,得到了试验件的损伤破坏形貌以及载荷和能量的历程曲线。基于ABAQUS/Explicit平台二次开发得到了模拟复合材料波纹腹板梁冲...为了探究复合材料波纹腹板梁在坠撞过程中的吸能性能,对复合材料波纹腹板梁试验件进行了动态冲击压溃试验研究,得到了试验件的损伤破坏形貌以及载荷和能量的历程曲线。基于ABAQUS/Explicit平台二次开发得到了模拟复合材料波纹腹板梁冲击压溃过程的仿真分析模型,模型采用了改进的Hashin损伤判定准则和Choi-Chang准则综合判断单元失效,并结合Cohesive界面单元,可较为真实地反映所研究复合材料层合结构的各向异性和渐进损伤特性。通过数值模拟得到了能量评估参数比吸能(Specific energy absorption,SEA)和平均压溃载荷,与试验结果进行了对比分析。基于仿真分析模型,本文进一步研究了不同波数的复合材料波纹腹板梁的吸能能力。数值模拟结果表明:波纹腹板梁在冲击载荷作用下发生了渐进压溃失效;平均压溃载荷的相对误差较小,验证了模型的有效性;在腹板单波长度不变的情况下,波纹腹板梁的长度对抗冲击吸能的影响较大。当波纹腹板梁长度较小时,结构容易失稳,无法有效地吸收能量。展开更多
文摘Web网页中往往包含许多主题噪声,准确地自动抽取关键词成为技术难点。提出了一个文本对象网络模型DON,给出了对象节点的中心度概念和基于中心度的影响因子传播规则,并据此自动聚集DON中的主题社区(topic society),从而提高了模型的抗噪能力。提出一个基于DON的网页关键词自动抽取算法KEYDON(Keywords Extraction Algorithm Based on DON)。实验结果表明,与基于DocView模型的相应算法相比,KEYDON的准确率提高了近20%,这说明DON模型具有较强的抑制主题噪声能力。
文摘Purpose: Communicating scientific results to the public is essential to inspire future researchers and ensure that discoveries are exploited. News stories about research are a key communication pathway for this and have been manually monitored to assess the extent of press coverage of scholarship.Design/methodology/Approach: To make larger scale studies practical, this paper introduces an automatic method to extract citations from newspaper stories to large sets of academic journals. Curated ProQuest queries were used to search for citations to 9,639 Science and3,412 Social Science Web of Science(WoS) journals from eight UK daily newspapers during2006–2015. False matches were automatically filtered out by a new program, with 94% of the remaining stories meaningfully citing research.Findings: Most Science(95%) and Social Science(94%) journals were never cited by these newspapers. Half of the cited Science journals covered medical or health-related topics,whereas 43% of the Social Sciences journals were related to psychiatry or psychology. From the citing news stories, 60% described research extensively and 53% used multiple sources,but few commented on research quality.Research Limitations: The method has only been tested in English and from the ProQuest Newspapers database.Practical implications: Others can use the new method to systematically harvest press coverage of research.Originality/value: An automatic method was introduced and tested to extract citations from newspaper stories to large sets of academic journals.
文摘为了探究复合材料波纹腹板梁在坠撞过程中的吸能性能,对复合材料波纹腹板梁试验件进行了动态冲击压溃试验研究,得到了试验件的损伤破坏形貌以及载荷和能量的历程曲线。基于ABAQUS/Explicit平台二次开发得到了模拟复合材料波纹腹板梁冲击压溃过程的仿真分析模型,模型采用了改进的Hashin损伤判定准则和Choi-Chang准则综合判断单元失效,并结合Cohesive界面单元,可较为真实地反映所研究复合材料层合结构的各向异性和渐进损伤特性。通过数值模拟得到了能量评估参数比吸能(Specific energy absorption,SEA)和平均压溃载荷,与试验结果进行了对比分析。基于仿真分析模型,本文进一步研究了不同波数的复合材料波纹腹板梁的吸能能力。数值模拟结果表明:波纹腹板梁在冲击载荷作用下发生了渐进压溃失效;平均压溃载荷的相对误差较小,验证了模型的有效性;在腹板单波长度不变的情况下,波纹腹板梁的长度对抗冲击吸能的影响较大。当波纹腹板梁长度较小时,结构容易失稳,无法有效地吸收能量。
