The microstructure and mechanical properties of magnesium （Mg） alloys are significantly influenced by the casting process. In this paper, a comparative study on microstructure and mechanical properties at ambient an...The microstructure and mechanical properties of magnesium （Mg） alloys are significantly influenced by the casting process. In this paper, a comparative study on microstructure and mechanical properties at ambient and elevated temperatures of AZ91-2wt.% Ca （AZX912） Mg alloy samples prepared by gravity casting （GC）, squeeze casting （SC） and rheo-squeeze casting （RSC）, respectively, was carried out. The results show that mMg grains in SC and RSC samples are significantly refined compared to the GC sample. The average secondary dendritic arm spacing of AZX912 alloy samples decreases in the order of GC, SC and RSC. As testing temperature increases from 25 ~C to 200 ~C, strength of AZX912 alloy samples is reduced, while their elongation is increased continuously. Compared to GC and SC processes, RSC process can improve the mechanical properties of AZX912 alloy at both ambient and elevated temperatures. The enhancement of mechanical properties of RSC sample over GC and SC samples mainly results from grain refinement in the as-cast microstructure of AZX912 alloy.展开更多
目的:探讨超声(US)和多层螺旋CT(MSCT)两种检查方法在胃肠道间质瘤(GIST)诊断中的应用价值。方法:选择2015年2月到2017年2月在我院诊治的疑似胃肠道间质瘤患者60例作为研究对象,均进行超声与MSCT检查,判定诊断效果与检查特征。结果:60...目的:探讨超声(US)和多层螺旋CT(MSCT)两种检查方法在胃肠道间质瘤(GIST)诊断中的应用价值。方法:选择2015年2月到2017年2月在我院诊治的疑似胃肠道间质瘤患者60例作为研究对象,均进行超声与MSCT检查,判定诊断效果与检查特征。结果:60例患者经过病理诊断为胃肠道间质瘤35例,诊断为非胃肠道间质瘤25例,胃肠道间质瘤35例中超声表现为低回声32例,伴后方声影27例,内部血流丰富23例,轮廓模糊24例;非胃肠道间质瘤25例中超声表现为低回声8例,伴后方声影6例,内部血流丰富9例,轮廓模糊5例,两组超声特征对比有明显差异(P<0.05)。胃肠道间质瘤患者的CT增强成像参数AT(增强开始时间,Arrival time)、TTP(达峰时间,Time to peak enhancement)值明显低于非胃肠道间质瘤患者(P<0.05),而T1/2(强度半降时间,Time from peak to half)、AUC(曲线下面积,Area under the curve)与EI(增强强度,Enhanced intensity)值明显低于非胃肠道间质瘤患者(P<0.05)。US诊断胃肠道间质瘤的敏感性与特异性分别为80.0%和92.0%,MSCT诊断胃肠道间质瘤的敏感性与特异性分别为97.1%和100.0%,MSCT在胃肠道间质瘤诊断中的敏感性明显高于超声(P<0.05)。结论:US和MSCT检查均可应用于胃肠道间质瘤的诊断,其中MSCT检查效果更佳,具有很好的应用价值,应加以推广。展开更多
恶性纤维组织细胞瘤为一种罕见病,多误诊为不典型纤维黄色瘤或上皮样肉瘤。患者男,67岁。因左大腿内侧结节3月,进行性增大1月就诊。皮损组织病理检查示:肿瘤中成分呈多形性表现,部分细胞似成纤维细胞样交织排列呈漩涡状;有些细胞似组织...恶性纤维组织细胞瘤为一种罕见病,多误诊为不典型纤维黄色瘤或上皮样肉瘤。患者男,67岁。因左大腿内侧结节3月,进行性增大1月就诊。皮损组织病理检查示:肿瘤中成分呈多形性表现,部分细胞似成纤维细胞样交织排列呈漩涡状;有些细胞似组织细胞样,可见形状怪异的多核巨细胞。免疫组化:Vim(+)、CD163(+)、CD68(+)、CD34血管(+)、Ki-67 index 30%。展开更多
基金financially supported by the National Natural Science Foundation of China(No.51601076)the Natural Science Fund for Colleges and Universities in Jiangsu Province(No.16KJB430013,17KJA430005)
文摘The microstructure and mechanical properties of magnesium （Mg） alloys are significantly influenced by the casting process. In this paper, a comparative study on microstructure and mechanical properties at ambient and elevated temperatures of AZ91-2wt.% Ca （AZX912） Mg alloy samples prepared by gravity casting （GC）, squeeze casting （SC） and rheo-squeeze casting （RSC）, respectively, was carried out. The results show that mMg grains in SC and RSC samples are significantly refined compared to the GC sample. The average secondary dendritic arm spacing of AZX912 alloy samples decreases in the order of GC, SC and RSC. As testing temperature increases from 25 ~C to 200 ~C, strength of AZX912 alloy samples is reduced, while their elongation is increased continuously. Compared to GC and SC processes, RSC process can improve the mechanical properties of AZX912 alloy at both ambient and elevated temperatures. The enhancement of mechanical properties of RSC sample over GC and SC samples mainly results from grain refinement in the as-cast microstructure of AZX912 alloy.
文摘目的:探讨超声(US)和多层螺旋CT(MSCT)两种检查方法在胃肠道间质瘤(GIST)诊断中的应用价值。方法:选择2015年2月到2017年2月在我院诊治的疑似胃肠道间质瘤患者60例作为研究对象,均进行超声与MSCT检查,判定诊断效果与检查特征。结果:60例患者经过病理诊断为胃肠道间质瘤35例,诊断为非胃肠道间质瘤25例,胃肠道间质瘤35例中超声表现为低回声32例,伴后方声影27例,内部血流丰富23例,轮廓模糊24例;非胃肠道间质瘤25例中超声表现为低回声8例,伴后方声影6例,内部血流丰富9例,轮廓模糊5例,两组超声特征对比有明显差异(P<0.05)。胃肠道间质瘤患者的CT增强成像参数AT(增强开始时间,Arrival time)、TTP(达峰时间,Time to peak enhancement)值明显低于非胃肠道间质瘤患者(P<0.05),而T1/2(强度半降时间,Time from peak to half)、AUC(曲线下面积,Area under the curve)与EI(增强强度,Enhanced intensity)值明显低于非胃肠道间质瘤患者(P<0.05)。US诊断胃肠道间质瘤的敏感性与特异性分别为80.0%和92.0%,MSCT诊断胃肠道间质瘤的敏感性与特异性分别为97.1%和100.0%,MSCT在胃肠道间质瘤诊断中的敏感性明显高于超声(P<0.05)。结论:US和MSCT检查均可应用于胃肠道间质瘤的诊断,其中MSCT检查效果更佳,具有很好的应用价值,应加以推广。
文摘恶性纤维组织细胞瘤为一种罕见病,多误诊为不典型纤维黄色瘤或上皮样肉瘤。患者男,67岁。因左大腿内侧结节3月,进行性增大1月就诊。皮损组织病理检查示:肿瘤中成分呈多形性表现,部分细胞似成纤维细胞样交织排列呈漩涡状;有些细胞似组织细胞样,可见形状怪异的多核巨细胞。免疫组化:Vim(+)、CD163(+)、CD68(+)、CD34血管(+)、Ki-67 index 30%。
