目的系统评价中医药证据质量及推荐意见分级体系。方法计算机检索PubMed、EMbase、Web of Science、CNKI、WanFang Data和VIP数据库,搜集有关中医药证据质量与推荐意见分级标准的研究,检索时限均为建库至2021年6月。由2名研究者独立筛...目的系统评价中医药证据质量及推荐意见分级体系。方法计算机检索PubMed、EMbase、Web of Science、CNKI、WanFang Data和VIP数据库,搜集有关中医药证据质量与推荐意见分级标准的研究,检索时限均为建库至2021年6月。由2名研究者独立筛选文献、提取资料后,采用定性分析方法进行描述性分析。结果共纳入18个研究。其中8个同时关注证据质量及推荐等级的制订,9个仅关注证据质量等级的制订,1个仅关注推荐等级的制订。13个研究同时考虑了传统中医证据和现代医学证据来源,3个仅纳入古籍文献证据,1个仅关注中药上市后安全性评价,1个仅关注中医药真实世界研究。结论当前中医药相关的证据质量与推荐意见分级标准较多,有的仅针对中医特色证据,有的与现代医学证据一同探讨。大部分中医证据质量与推荐意见分级体系研究者希望充分重视古籍文献及专家经验对证据质量和推荐意见分级的重要性。展开更多
超薄磨耗层NovaChip?是近年来发展的一种新型预防养护技术,具有抗滑性能好、表面强度高、行车噪声低、防水性能突出等特点。以AC-13模拟原路面,选用密级配沥青混合料AC-13C、半开级配沥青混合料NovaChip Type C、开级配沥青混合料OGFC-1...超薄磨耗层NovaChip?是近年来发展的一种新型预防养护技术,具有抗滑性能好、表面强度高、行车噪声低、防水性能突出等特点。以AC-13模拟原路面,选用密级配沥青混合料AC-13C、半开级配沥青混合料NovaChip Type C、开级配沥青混合料OGFC-13 3种代表性沥青混合料为磨耗层,改性乳化沥青NovabondTM、SBS为黏结层材料,制作复合型试件,通过多功能层间测试试验仪对试件进行剪切试验,分析了磨耗层类型、黏结层种类及用量对层间抗剪强度的影响。试验结果表明,对同一种面层类型,粘结能力方面,改性乳化沥青NovabondTM>SBS。在相同黏结层油的最佳洒布量下,不同路面结构抗剪能力依次是NovaChip Type C>AC-13C>OGFC-13。展开更多
Mortars provide the continuity required for the stability and exclusion of weather elements in masonry assemblies. But because of the heterogeneity of the mortar, its mechanism of behaviour under different load effect...Mortars provide the continuity required for the stability and exclusion of weather elements in masonry assemblies. But because of the heterogeneity of the mortar, its mechanism of behaviour under different load effects is dependent on the properties of the constituents of the mortar. The aim of paper is to determine the effect sand grading for various cement-sand-lime mortar designations (BS) and strength classes (EC) on the compressive strength and stiffness of mortar. Two silica sands;HST 95 and HST60 were used to make mortars in three strength classes: M2, M4 and M6, corresponding to mortar designations iv, iii and ii respectively. The results show that mortar made with the HST60 sand (coarser grading) usually resulted in mortar with a higher compressive strength and stiffness. The One Way ANOVA analysis of both compressive strength and stiffness at a significance level of 5% on the effect of sand grading on the two parameters also shows that they are both significant. There is also strong evidence of a linear correlation between the stiffness and compressive strength. The results indicate that in order to replicate full scale behaviour of masonry at model scales, the grading of fine aggregate in the models should be similar so as to properly model full scale behavior.展开更多
The mechanical properties of recycled aggregates concrete from demolition have been studied for several years. It has been documented that rheological properties of these concrete are generally affected by use of recy...The mechanical properties of recycled aggregates concrete from demolition have been studied for several years. It has been documented that rheological properties of these concrete are generally affected by use of recycled aggregates. They could present mechanical properties less affected by the presence of recycled aggregates if the initial concrete were of good quality. However, manufacturing problems, mainly attributed to the angular character of these aggregates and to the granulometry of recycled sand, limit their industrial use. The worth point of this study consists in the optimization of the concrete formulation using specific admixture, adapted to this aggregates in order to facilitate its manufacturing. It shows that the new generation of superplasticizers containing some copolymer polycarboxylate makes it possible to significantly improve the fluidity of the recycled aggregates concrete in its fresh state. The aim of this research is to control rheologica] properties of fresh recycled aggregates concrete with fine and coarse recycled aggregates to limit the negative influence of aggregates on mechanical properties of concrete.展开更多
文摘目的系统评价中医药证据质量及推荐意见分级体系。方法计算机检索PubMed、EMbase、Web of Science、CNKI、WanFang Data和VIP数据库,搜集有关中医药证据质量与推荐意见分级标准的研究,检索时限均为建库至2021年6月。由2名研究者独立筛选文献、提取资料后,采用定性分析方法进行描述性分析。结果共纳入18个研究。其中8个同时关注证据质量及推荐等级的制订,9个仅关注证据质量等级的制订,1个仅关注推荐等级的制订。13个研究同时考虑了传统中医证据和现代医学证据来源,3个仅纳入古籍文献证据,1个仅关注中药上市后安全性评价,1个仅关注中医药真实世界研究。结论当前中医药相关的证据质量与推荐意见分级标准较多,有的仅针对中医特色证据,有的与现代医学证据一同探讨。大部分中医证据质量与推荐意见分级体系研究者希望充分重视古籍文献及专家经验对证据质量和推荐意见分级的重要性。
文摘超薄磨耗层NovaChip?是近年来发展的一种新型预防养护技术,具有抗滑性能好、表面强度高、行车噪声低、防水性能突出等特点。以AC-13模拟原路面,选用密级配沥青混合料AC-13C、半开级配沥青混合料NovaChip Type C、开级配沥青混合料OGFC-13 3种代表性沥青混合料为磨耗层,改性乳化沥青NovabondTM、SBS为黏结层材料,制作复合型试件,通过多功能层间测试试验仪对试件进行剪切试验,分析了磨耗层类型、黏结层种类及用量对层间抗剪强度的影响。试验结果表明,对同一种面层类型,粘结能力方面,改性乳化沥青NovabondTM>SBS。在相同黏结层油的最佳洒布量下,不同路面结构抗剪能力依次是NovaChip Type C>AC-13C>OGFC-13。
文摘Mortars provide the continuity required for the stability and exclusion of weather elements in masonry assemblies. But because of the heterogeneity of the mortar, its mechanism of behaviour under different load effects is dependent on the properties of the constituents of the mortar. The aim of paper is to determine the effect sand grading for various cement-sand-lime mortar designations (BS) and strength classes (EC) on the compressive strength and stiffness of mortar. Two silica sands;HST 95 and HST60 were used to make mortars in three strength classes: M2, M4 and M6, corresponding to mortar designations iv, iii and ii respectively. The results show that mortar made with the HST60 sand (coarser grading) usually resulted in mortar with a higher compressive strength and stiffness. The One Way ANOVA analysis of both compressive strength and stiffness at a significance level of 5% on the effect of sand grading on the two parameters also shows that they are both significant. There is also strong evidence of a linear correlation between the stiffness and compressive strength. The results indicate that in order to replicate full scale behaviour of masonry at model scales, the grading of fine aggregate in the models should be similar so as to properly model full scale behavior.
文摘The mechanical properties of recycled aggregates concrete from demolition have been studied for several years. It has been documented that rheological properties of these concrete are generally affected by use of recycled aggregates. They could present mechanical properties less affected by the presence of recycled aggregates if the initial concrete were of good quality. However, manufacturing problems, mainly attributed to the angular character of these aggregates and to the granulometry of recycled sand, limit their industrial use. The worth point of this study consists in the optimization of the concrete formulation using specific admixture, adapted to this aggregates in order to facilitate its manufacturing. It shows that the new generation of superplasticizers containing some copolymer polycarboxylate makes it possible to significantly improve the fluidity of the recycled aggregates concrete in its fresh state. The aim of this research is to control rheologica] properties of fresh recycled aggregates concrete with fine and coarse recycled aggregates to limit the negative influence of aggregates on mechanical properties of concrete.
