背景肠道准备是结肠镜检查前的必要环节,其研究主题较为分散.掌握肠道准备的研究现状及发展趋势,对于疾病研究和实际临床工作具有重要的价值,而目前该领域采用文献计量学的形式对此进行归纳和总结的研究是缺乏的.目的了解结肠镜检查前...背景肠道准备是结肠镜检查前的必要环节,其研究主题较为分散.掌握肠道准备的研究现状及发展趋势,对于疾病研究和实际临床工作具有重要的价值,而目前该领域采用文献计量学的形式对此进行归纳和总结的研究是缺乏的.目的了解结肠镜检查前肠道准备相关研究在国内外的研究热点和发展趋势,以为研究者及临床工作者提供指导价值.方法检索建库至2022-09-10中国知网(CNKI)、万方、维普、中国生物医学文献数据库(CBM)、Web of Science核心数据集中与肠道准备主题相关的文献,采用CiteSpace 6.1.R3软件对年发文量、国家、机构、发文作者、关键词及聚类、文献共被引情况进行可视化分析.结果共分别纳入中、英文文献2340篇、2674篇,年发文量均呈逐年上升趋势,国际上最高产作者为Hassan Cesare,最高产国家为美国、韩国、英国等,国内最高产作者为孟小芬、张媛媛、钮美娥,最高产机构为苏州大学第一附属医院、中国人民解放军总医院、西安交通大学附属第二医院,研究热点为肠道准备质量、肠道准备方案的研究、特殊人群的肠道准备.结论国内外肠道准备相关的研究具备一定研究基础,国内研究能紧跟国际研究热点,但国际间、团队间合作仍需加强,未来应扩大基于更广泛人群的、更契合大数据时代发展的肠道准备相关研究产出,以为临床提供更高质量的研究证据.展开更多
The almost completely dense copper was prepared by ultrafine copper powder prepared with both methods of electrolysis and novel water-gas atomization through cold isostatic pressing(CIP)and sintering under atmospheric...The almost completely dense copper was prepared by ultrafine copper powder prepared with both methods of electrolysis and novel water-gas atomization through cold isostatic pressing(CIP)and sintering under atmospheric hydrogen.Fine copper powder possesses the higher sintering driving force,thereby promoting shrinkage and densification during the sintering process.The grain size of sintered samples by electrolytic copper powder is smaller than that prepared by the atomized copper powder,and the twin crystals are particularly prone to forming in the former sintered microstructure due to the raw powder with low oxygen content and high residual stress originating from the CIP process.The relative density of samples by electrolytic and atomized powder at 1000℃ sintering temperature achieves 99.3%and 97.4%,respectively,significantly higher than that of the powder metallurgy copper parts reported in the literature.Correspondingly,the ultimate tensile strength and yield strength of samples by both kinds of copper powder are approximately similar,while the elongation of the sintered sample by the electrolytic powder(60%)is apparently higher than the atomized powder(44%).The superior performance of samples fabricated by electrolytic powder is inferred from the full density and low oxygen level for there is no cuprous oxide in the grain boundaries.展开更多
文摘背景肠道准备是结肠镜检查前的必要环节,其研究主题较为分散.掌握肠道准备的研究现状及发展趋势,对于疾病研究和实际临床工作具有重要的价值,而目前该领域采用文献计量学的形式对此进行归纳和总结的研究是缺乏的.目的了解结肠镜检查前肠道准备相关研究在国内外的研究热点和发展趋势,以为研究者及临床工作者提供指导价值.方法检索建库至2022-09-10中国知网(CNKI)、万方、维普、中国生物医学文献数据库(CBM)、Web of Science核心数据集中与肠道准备主题相关的文献,采用CiteSpace 6.1.R3软件对年发文量、国家、机构、发文作者、关键词及聚类、文献共被引情况进行可视化分析.结果共分别纳入中、英文文献2340篇、2674篇,年发文量均呈逐年上升趋势,国际上最高产作者为Hassan Cesare,最高产国家为美国、韩国、英国等,国内最高产作者为孟小芬、张媛媛、钮美娥,最高产机构为苏州大学第一附属医院、中国人民解放军总医院、西安交通大学附属第二医院,研究热点为肠道准备质量、肠道准备方案的研究、特殊人群的肠道准备.结论国内外肠道准备相关的研究具备一定研究基础,国内研究能紧跟国际研究热点,但国际间、团队间合作仍需加强,未来应扩大基于更广泛人群的、更契合大数据时代发展的肠道准备相关研究产出,以为临床提供更高质量的研究证据.
基金Project(92066205)supported by the National Natural Science Foundation of ChinaProject(2019-Z10)supported by the State Key Lab for Advanced Metals and Materials of ChinaProject(FRF-MP-20-52)supported by the Fundamental Research Funds for the Central Universities,China。
文摘The almost completely dense copper was prepared by ultrafine copper powder prepared with both methods of electrolysis and novel water-gas atomization through cold isostatic pressing(CIP)and sintering under atmospheric hydrogen.Fine copper powder possesses the higher sintering driving force,thereby promoting shrinkage and densification during the sintering process.The grain size of sintered samples by electrolytic copper powder is smaller than that prepared by the atomized copper powder,and the twin crystals are particularly prone to forming in the former sintered microstructure due to the raw powder with low oxygen content and high residual stress originating from the CIP process.The relative density of samples by electrolytic and atomized powder at 1000℃ sintering temperature achieves 99.3%and 97.4%,respectively,significantly higher than that of the powder metallurgy copper parts reported in the literature.Correspondingly,the ultimate tensile strength and yield strength of samples by both kinds of copper powder are approximately similar,while the elongation of the sintered sample by the electrolytic powder(60%)is apparently higher than the atomized powder(44%).The superior performance of samples fabricated by electrolytic powder is inferred from the full density and low oxygen level for there is no cuprous oxide in the grain boundaries.
