基于文献分析法的药物临床试验信息化建设

目的：梳理药物临床试验信息化建设研究脉络，了解并掌握药物临床试验信息化建设研究热点和发展趋势。方法：本研究采用知识图谱CiteSpaceⅤ软件，在2000年至2020年中国知网数据库391条文献的基础上，从文献数量分析、研究机构分析、作者分析、研究热点主题以及研究趋势分析等角度进行了深入探讨，并绘制知识图谱，梳理药物临床试验信息化建设研究脉络。结果：分析表明近20年来药物临床信息化建设相关研究论文发表数量波动上升，主要研究机构在该领域大都有较强的研究能力，但研究机构间的联系还较为松散，学者间的学术交流还有待加强。在热点研究上的转变体现了该领域更加注重系统化和保护受试者权益。 结论：药物临床试验信息化建设研究热点主要集中于临床试验、药物临床试验、质量控制等方面。通过信息化建设进一步提高试验管理效能，保证药物临床试验可靠规范，有效降低药物临床试验风险隐患是未来研究趋势。

Review:Mechanism of Reactive Element Effect—Oxide Pegging

High temperature protective coatings are involved in a wide variety of applications including aero engines and gas turbines.Reactive elements,including all rare-earth elements as well as Ti,Zr,and Hf,are increasingly used to modify high temperature protective coatings,and their main effects are reducing scale growth and improving scale adhesion.The mechanism through which reactive elements work is yet to be clearly understood.The current mechanism comprises"enhanced scale plasticity","graded seal mechanism","modification to growth process","chemical bonding","the vacancy sink model","oxide pegging","dynamic segregation theory",and"the sulfur effect theory".Among these,oxide pegging is perhaps the most important one,although some people may disagree.Oxide pegging is the result of the mechanical joining of an oxide to its corresponding alloy;it is a result of either the internal oxidation of added reactive elements or dispersed oxide particles growing in size and extending into the alloy.This paper offers an overview of the research progress on oxide pegging,including its proposed,the relationship between the peg and scale adherence,improving the"key-on"effect,and the peg formation and growth under different conditions(the doped reactive element with a low or high solid solute in the alloy,dispersed oxide added in the alloy,and two reactive elements doped into the alloy).Moreover,it sheds light on the model’s inability to explain the surface application of reactive elements on the alloy.Finally,the paper suggests future studies on this model,like focusing on how to obtain the ideal oxide pegging,developing a new model for oxide peg formation and growth with two or more reactive elements added to the alloy,and the cooperation effect between the oxide pegging and other mechanisms.The paper’s objective is to offer a better understanding of oxide pegging and to provide theoretical support for the studies on the reactive element effect and the design of materials in thermal barrier coating systems.