Effect of Ti addition on the microstructure and strengthening behavior in press hardening steels(PHS)was analyzed by optical metallography(OM),scanning electron microscopy(SEM),transmission electron microscopy(TEM)and...Effect of Ti addition on the microstructure and strengthening behavior in press hardening steels(PHS)was analyzed by optical metallography(OM),scanning electron microscopy(SEM),transmission electron microscopy(TEM)and X-ray diffraction(XRD).The results show that the microstructure of PHS is martensite,and two sizes of particles disperse in the martensite matrix during the forming and quenching process.The size of the bigger particles is between 100 and 200 nm,and the small particles are nanometer-sized.The quantity of the particles has a positive relation with the Ti content.More importantly,the microstructure and strengthening mechanism are affected by the precipitating behavior of the particles.Besides the prior austenite grain,martensite packet,block and lath are refined by Ti addition.The steels are strengthened by the fine grains,martensite substructure and precipitates.The uniformly distributed dislocation in the martensite lath,the density of which is between 3.0?10^(14) cm^(–2) and 5.0?10^(14) cm^(–2),strengthens the steels through associating with fine carbide particles.展开更多
以超高盐(以Na Cl计为70 g/L)榨菜废水为研究对象,通过中试考察温度对ASBBR反应器处理效能及微生物种群的影响。结果表明,季节温度变化对系统去除COD的效能影响显著。当负荷为3 kg COD/(m^3·d)时,反应器在夏季(26~39℃)、秋季(13~2...以超高盐(以Na Cl计为70 g/L)榨菜废水为研究对象,通过中试考察温度对ASBBR反应器处理效能及微生物种群的影响。结果表明,季节温度变化对系统去除COD的效能影响显著。当负荷为3 kg COD/(m^3·d)时,反应器在夏季(26~39℃)、秋季(13~25℃)、冬季(3~12℃)的COD平均去除率分别为89.43%、78.51%、66.35%。PCR-DGGE分析结果表明,超高盐榨菜废水处理系统的微生物种群与接种污泥相比发生了显著变化;温度对系统微生物种群结构及优势微生物种群影响显著,微生物种群丰富度呈现出夏季>秋季>冬季的规律,夏季与秋季、冬季的微生物种群相似性分别为49.6%、45.2%;根据16S r DNA V3区测序结果,系统优势微生物种群主要为厌氧嗜盐菌,温度对有机物降解优势微生物功能菌属影响显著,夏季系统中主要有Marinobacterium、Lutaonella、Cellulophaga、Arcobacter、Methanobacterium,冬季系统主要有Marinobacterium、Arcobacter、Methanobacterium。展开更多
基金Project(U1460101)supported by the National Natural Science Foundation of ChinaProject(20120006120002)supported by Specialized Research Fund for the Doctoral Program of Higher Education,China
文摘Effect of Ti addition on the microstructure and strengthening behavior in press hardening steels(PHS)was analyzed by optical metallography(OM),scanning electron microscopy(SEM),transmission electron microscopy(TEM)and X-ray diffraction(XRD).The results show that the microstructure of PHS is martensite,and two sizes of particles disperse in the martensite matrix during the forming and quenching process.The size of the bigger particles is between 100 and 200 nm,and the small particles are nanometer-sized.The quantity of the particles has a positive relation with the Ti content.More importantly,the microstructure and strengthening mechanism are affected by the precipitating behavior of the particles.Besides the prior austenite grain,martensite packet,block and lath are refined by Ti addition.The steels are strengthened by the fine grains,martensite substructure and precipitates.The uniformly distributed dislocation in the martensite lath,the density of which is between 3.0?10^(14) cm^(–2) and 5.0?10^(14) cm^(–2),strengthens the steels through associating with fine carbide particles.
文摘以超高盐(以Na Cl计为70 g/L)榨菜废水为研究对象,通过中试考察温度对ASBBR反应器处理效能及微生物种群的影响。结果表明,季节温度变化对系统去除COD的效能影响显著。当负荷为3 kg COD/(m^3·d)时,反应器在夏季(26~39℃)、秋季(13~25℃)、冬季(3~12℃)的COD平均去除率分别为89.43%、78.51%、66.35%。PCR-DGGE分析结果表明,超高盐榨菜废水处理系统的微生物种群与接种污泥相比发生了显著变化;温度对系统微生物种群结构及优势微生物种群影响显著,微生物种群丰富度呈现出夏季>秋季>冬季的规律,夏季与秋季、冬季的微生物种群相似性分别为49.6%、45.2%;根据16S r DNA V3区测序结果,系统优势微生物种群主要为厌氧嗜盐菌,温度对有机物降解优势微生物功能菌属影响显著,夏季系统中主要有Marinobacterium、Lutaonella、Cellulophaga、Arcobacter、Methanobacterium,冬季系统主要有Marinobacterium、Arcobacter、Methanobacterium。
