在医学论文中,“ppm、ppb、ppt”这类英文缩写常常被作者作为单位符号使用,但“ppm、ppb、ppt”既不是数学符号,更不是单位符号,只是表示数量份额的英文名词缩写(英文全称分别为 parts per milion、pants per bilion、parts per tmiion...在医学论文中,“ppm、ppb、ppt”这类英文缩写常常被作者作为单位符号使用,但“ppm、ppb、ppt”既不是数学符号,更不是单位符号,只是表示数量份额的英文名词缩写(英文全称分别为 parts per milion、pants per bilion、parts per tmiion)。在实际研究中仪器测量的数值可能会以“ppm、ppb、ppt”形式给出结果,作者在撰写文章进行数据描述时则需对“ppm、ppb、ppt”进行换算。对溶液而言,换算前需了解体积比还是质量比。1rg/m是质量-体积比,如果溶液的密度是1g/mL,则1mg/mL,相当于Ppm;如果溶液密度不是1gmL,则需要进行换算。展开更多
在医学论文中,“ppm、ppb、ppt”这类英文缩写常常被作者作为单位符号使用,但“ppm、ppb、ppt”既不是数学符号,更不是单位符号,只是表示数量份额的英文名词缩写(英文全称分别为parts per million、parts per billion、parts per trilli...在医学论文中,“ppm、ppb、ppt”这类英文缩写常常被作者作为单位符号使用,但“ppm、ppb、ppt”既不是数学符号,更不是单位符号,只是表示数量份额的英文名词缩写(英文全称分别为parts per million、parts per billion、parts per trillion)。在实际研究中,仪器测量的数值可能会以“ppm、ppb、ppt”形式给出结果,作者在撰写文章进行数据描述时则需对“ppm、ppb、ppt”进行换算。展开更多
Previous Particle Boundary(PPB),as the detrimental structure in Powder Metallurgy(PM)components,should be eliminated by subsequent hot process to improve the mechanical properties.The objective is to investigate the D...Previous Particle Boundary(PPB),as the detrimental structure in Powder Metallurgy(PM)components,should be eliminated by subsequent hot process to improve the mechanical properties.The objective is to investigate the Dynamic Recrystallization(DRX)nucleation mechanisms and grain growth behavior of the 3rd-generation PM superalloy with PPB structure.Microstructure observation reveals that PPB decorated with(Ti,Ta,Nb)C carbides belongs to the discontinuous chain-like structure.The elimination of PPB networks can be achieved effectively via hot deformation due to the occurrence of DRX.Four different DRX nucleation mechanisms were proposed and discussed in detail according to the special microstructure characteristics of the PM superalloy.Firstly,local lattice rotations can be detected in the vicinity of(Ti,Ta,Nb)C carbides during hot deformation and thus PPB structure serves as the preferential nucleation sites for DRX grains via Particle-Stimulated Nucleation(PSN).Then,Discontinuous-DRX(DDRX)characterized by grain boundary bulging dominates the microstructure refinement and Continuous-DRX(CDRX)operated by subgrain rotation can be regarded as an important assistant mechanism.At last,the initial Σ3 boundaries would lose their twin characteristics owing to the crystal rotation and then transform into the general High Angle Grain Boundaries(HAGBs).The distorted twins provide additional DRX nucleation sites,viz.,twin-assisted nucleation.Particular attention was focused on the grain growth behavior of the PM superalloy in subsequent annealing process.The recrystallization temperature was determined to be about 1110.C and 1140.C can be considered as the critical temperature for grain growth.The findings would provide theoretical support for microstructure refinement of the 3rd-generation PM superalloy,which is of pivotal significance for improving the mechanical properties of aviation components.展开更多
文摘在医学论文中,“ppm、ppb、ppt”这类英文缩写常常被作者作为单位符号使用,但“ppm、ppb、ppt”既不是数学符号,更不是单位符号,只是表示数量份额的英文名词缩写(英文全称分别为 parts per milion、pants per bilion、parts per tmiion)。在实际研究中仪器测量的数值可能会以“ppm、ppb、ppt”形式给出结果,作者在撰写文章进行数据描述时则需对“ppm、ppb、ppt”进行换算。对溶液而言,换算前需了解体积比还是质量比。1rg/m是质量-体积比,如果溶液的密度是1g/mL,则1mg/mL,相当于Ppm;如果溶液密度不是1gmL,则需要进行换算。
文摘在医学论文中,“ppm、ppb、ppt”这类英文缩写常常被作者作为单位符号使用,但“ppm、ppb、ppt”既不是数学符号,更不是单位符号,只是表示数量份额的英文名词缩写(英文全称分别为parts per million、parts per billion、parts per trillion)。在实际研究中,仪器测量的数值可能会以“ppm、ppb、ppt”形式给出结果,作者在撰写文章进行数据描述时则需对“ppm、ppb、ppt”进行换算。
基金supported by the National Natural Science Foundation of China(No.52175363)the National Key Research and Development Program,China(Nos.XXXXKF2019-8-1,XX-XX-0015-0087)。
文摘Previous Particle Boundary(PPB),as the detrimental structure in Powder Metallurgy(PM)components,should be eliminated by subsequent hot process to improve the mechanical properties.The objective is to investigate the Dynamic Recrystallization(DRX)nucleation mechanisms and grain growth behavior of the 3rd-generation PM superalloy with PPB structure.Microstructure observation reveals that PPB decorated with(Ti,Ta,Nb)C carbides belongs to the discontinuous chain-like structure.The elimination of PPB networks can be achieved effectively via hot deformation due to the occurrence of DRX.Four different DRX nucleation mechanisms were proposed and discussed in detail according to the special microstructure characteristics of the PM superalloy.Firstly,local lattice rotations can be detected in the vicinity of(Ti,Ta,Nb)C carbides during hot deformation and thus PPB structure serves as the preferential nucleation sites for DRX grains via Particle-Stimulated Nucleation(PSN).Then,Discontinuous-DRX(DDRX)characterized by grain boundary bulging dominates the microstructure refinement and Continuous-DRX(CDRX)operated by subgrain rotation can be regarded as an important assistant mechanism.At last,the initial Σ3 boundaries would lose their twin characteristics owing to the crystal rotation and then transform into the general High Angle Grain Boundaries(HAGBs).The distorted twins provide additional DRX nucleation sites,viz.,twin-assisted nucleation.Particular attention was focused on the grain growth behavior of the PM superalloy in subsequent annealing process.The recrystallization temperature was determined to be about 1110.C and 1140.C can be considered as the critical temperature for grain growth.The findings would provide theoretical support for microstructure refinement of the 3rd-generation PM superalloy,which is of pivotal significance for improving the mechanical properties of aviation components.
