Diffusion couples,WC/Co-1at.%C,V8C7/Co,and WC/Co-0.3wt.%V8C7 were constructed and annealed at temperatures ranging from 1100 to 1300℃. The concentration profile of V and W atoms in these couples were measured by EPMA...Diffusion couples,WC/Co-1at.%C,V8C7/Co,and WC/Co-0.3wt.%V8C7 were constructed and annealed at temperatures ranging from 1100 to 1300℃. The concentration profile of V and W atoms in these couples were measured by EPMA. Aided by Thermo-calc ＆ DICTRA software package,the concentration profiles of W and V in established diffusion couples were calculated by the moving boundary model according to revised dynamic parameters and MOB database,respectively. Then the concentration profile of W in Co binder during sintering WC-Co cemented carbide was simulated by the Cell model. It can provide reference for composition and sintering process design of cemented carbides with high performance. Meanwhile,the validity of revised dynamic parameters of the W-C-Co-V system is verified by the comparison of experimental and simulated results.展开更多
Fe-Cr-Mo-Ni-C-Co alloy was quenched in liquid nitrogen and held for 24 h.Hardness tester,OM,XRD,SEM were used to investigate the mechanical properties and microstructures of the alloy.The results show that the hardnes...Fe-Cr-Mo-Ni-C-Co alloy was quenched in liquid nitrogen and held for 24 h.Hardness tester,OM,XRD,SEM were used to investigate the mechanical properties and microstructures of the alloy.The results show that the hardness increases by 1-2(HRC)and the compressive strength decreases slightly after cryogenic treatment.The increase in hardness is attributed to the transformation from austenite to martensite and the precipitation of the very tiny carbideη-Fe2C.The decrease in compressive strength is caused by residual stress.The great amount of carbides,such as Cr7C3 and Fe2MoC,in the alloy and the obvious difference in thermal expansion coefficient between these carbides and the matrix at the cryogenic temperatures lead to this residual stress.The microscopy of cryogenic martensite is different from that of the non-cryogenic martensite.The cryogenic martensite is long and fine;while the non-cryogenic martensite is short and coarse.There is obvious surface relief of the cryogenic martensite transformation.It is not orientational of this kind surface relief and the boundary of this surface relief is smooth and in a shape of butterfly.The surface relief in the non-cryogenic martensite is wide and arranged in parallel,and the boundary of surface relief is not smooth.These characteristics may imply different growth ways of the two kinds of martensite.展开更多
为解决C语言数据类型在支持后下载应用的片上操作系统(COS)中无法完全满足应用程序数据的存储特性和安全需求的问题,分析了Java Card和C语言数据类型的属性,提出了一种基于 C 语言扩展的应用程序数据类型体系。根据数据分类,重点阐述了...为解决C语言数据类型在支持后下载应用的片上操作系统(COS)中无法完全满足应用程序数据的存储特性和安全需求的问题,分析了Java Card和C语言数据类型的属性,提出了一种基于 C 语言扩展的应用程序数据类型体系。根据数据分类,重点阐述了4种模块数据类型和5种应用数据类型。测试结果表明,该数据类型体系满足了COS应用程序数据的需求,有效提升了内存利用率和应用执行性能,为COS虚拟机运行时环境提供了高效的数据模型。展开更多
目的:评价A群C群脑膜炎球菌多糖结合疫苗(group A and group C meningococcal polysaccharide conjugate vaccine,MPCV-AC)和乙型肝炎疫苗(hepatitis B vaccine,HepB)同时接种后的安全性。方法:通过国家免疫规划信息系统和安徽省免疫规...目的:评价A群C群脑膜炎球菌多糖结合疫苗(group A and group C meningococcal polysaccharide conjugate vaccine,MPCV-AC)和乙型肝炎疫苗(hepatitis B vaccine,HepB)同时接种后的安全性。方法:通过国家免疫规划信息系统和安徽省免疫规划信息管理系统分别收集2020年至2022年安徽省适龄儿童MPCV-AC和HepB的疑似预防接种异常反应(adverse events following immunization,AEFI)数据和预防接种数据,比较2种疫苗同时接种和单独接种的AEFI的发生风险。结果:MPCV-AC第1剂次和HepB第3剂次同时接种、MPCV-AC第1剂次单独接种、HepB第3剂次单独接种的AEFI报告发生率分别为48.03/10万(280例)、56.37/10万(314例)、51.96/10万(283例);其中一般反应分别为43.91/10万(256例)、51.35/10万(286例)、48.65/10万(265例),异常反应分别为4.12/10万(24例)、4.85/10万(27例)、3.30/10万(18例)。同时接种组、单独接种组的AEFI发生风险、一般反应及异常反应的发生风险差异均无统计学意义。结论:MPCV-AC和HepB同时接种未增加AEFI的发生风险,可作为6月龄儿童同时接种MPCV-AC和HepB的科学依据。展开更多
基金the National Natural Science Foundation of China (No. 50471101)the Flan-ders-China Bilateral Project BIL 02/04.
文摘Diffusion couples,WC/Co-1at.%C,V8C7/Co,and WC/Co-0.3wt.%V8C7 were constructed and annealed at temperatures ranging from 1100 to 1300℃. The concentration profile of V and W atoms in these couples were measured by EPMA. Aided by Thermo-calc ＆ DICTRA software package,the concentration profiles of W and V in established diffusion couples were calculated by the moving boundary model according to revised dynamic parameters and MOB database,respectively. Then the concentration profile of W in Co binder during sintering WC-Co cemented carbide was simulated by the Cell model. It can provide reference for composition and sintering process design of cemented carbides with high performance. Meanwhile,the validity of revised dynamic parameters of the W-C-Co-V system is verified by the comparison of experimental and simulated results.
文摘Fe-Cr-Mo-Ni-C-Co alloy was quenched in liquid nitrogen and held for 24 h.Hardness tester,OM,XRD,SEM were used to investigate the mechanical properties and microstructures of the alloy.The results show that the hardness increases by 1-2(HRC)and the compressive strength decreases slightly after cryogenic treatment.The increase in hardness is attributed to the transformation from austenite to martensite and the precipitation of the very tiny carbideη-Fe2C.The decrease in compressive strength is caused by residual stress.The great amount of carbides,such as Cr7C3 and Fe2MoC,in the alloy and the obvious difference in thermal expansion coefficient between these carbides and the matrix at the cryogenic temperatures lead to this residual stress.The microscopy of cryogenic martensite is different from that of the non-cryogenic martensite.The cryogenic martensite is long and fine;while the non-cryogenic martensite is short and coarse.There is obvious surface relief of the cryogenic martensite transformation.It is not orientational of this kind surface relief and the boundary of this surface relief is smooth and in a shape of butterfly.The surface relief in the non-cryogenic martensite is wide and arranged in parallel,and the boundary of surface relief is not smooth.These characteristics may imply different growth ways of the two kinds of martensite.
文摘为解决C语言数据类型在支持后下载应用的片上操作系统(COS)中无法完全满足应用程序数据的存储特性和安全需求的问题,分析了Java Card和C语言数据类型的属性,提出了一种基于 C 语言扩展的应用程序数据类型体系。根据数据分类,重点阐述了4种模块数据类型和5种应用数据类型。测试结果表明,该数据类型体系满足了COS应用程序数据的需求,有效提升了内存利用率和应用执行性能,为COS虚拟机运行时环境提供了高效的数据模型。
文摘目的:评价A群C群脑膜炎球菌多糖结合疫苗(group A and group C meningococcal polysaccharide conjugate vaccine,MPCV-AC)和乙型肝炎疫苗(hepatitis B vaccine,HepB)同时接种后的安全性。方法:通过国家免疫规划信息系统和安徽省免疫规划信息管理系统分别收集2020年至2022年安徽省适龄儿童MPCV-AC和HepB的疑似预防接种异常反应(adverse events following immunization,AEFI)数据和预防接种数据,比较2种疫苗同时接种和单独接种的AEFI的发生风险。结果:MPCV-AC第1剂次和HepB第3剂次同时接种、MPCV-AC第1剂次单独接种、HepB第3剂次单独接种的AEFI报告发生率分别为48.03/10万(280例)、56.37/10万(314例)、51.96/10万(283例);其中一般反应分别为43.91/10万(256例)、51.35/10万(286例)、48.65/10万(265例),异常反应分别为4.12/10万(24例)、4.85/10万(27例)、3.30/10万(18例)。同时接种组、单独接种组的AEFI发生风险、一般反应及异常反应的发生风险差异均无统计学意义。结论:MPCV-AC和HepB同时接种未增加AEFI的发生风险,可作为6月龄儿童同时接种MPCV-AC和HepB的科学依据。
