Adding Ti particles to magnesium alloy simultaneously enhances its strength and ductility.However,how these particles influence on Mg alloy’s corrosion performance is seldom reported.The corrosion behavior of AZ31-Ti...Adding Ti particles to magnesium alloy simultaneously enhances its strength and ductility.However,how these particles influence on Mg alloy’s corrosion performance is seldom reported.The corrosion behavior of AZ31-Ti composites containing titanium nanoparticles(1.5 and 5 wt%)and micron particles(10 wt%)prepared by powder metallurgical in 3.5 wt%NaCl solution was investigated.The results indicate that Ti particles serve as the primary location for the cathodic hydrogen reduction reaction,resulting in intense galvanic corrosion between the Ti and Mg matrix.Ti nanoparticles distributed at the interface of the original AZ31 powder were in a discontinuous mesh structure,thus failing to act as a barrier against corrosion.The corrosion products with the existence of numerous cracks gradually peel off during the corrosion process and cannot protect the matrix.The average corrosion rate P_(w) of AZ31,AZ31-1.5%Ti,AZ31-5%Ti,and AZ31-10%Ti after 7 days of immersion is 27.55,105.65,283.67,and 99.35 mm/y,respectively.Therefore,AZ31-Ti composites can be considered as potential candidates for degradable fracturing tools.Otherwise,it is recommended to improve their corrosion resistance through surface treatment.展开更多
目的探讨基于增强计算机断层扫描(computed tomography,CT)影像组学在鉴别超声甲状腺成像报告和数据系统(thyroid imaging reporting and data system,TI-RADS)诊断为4A、4B类甲状腺微小结节良恶性的价值。方法回顾性入组2018年1月至202...目的探讨基于增强计算机断层扫描(computed tomography,CT)影像组学在鉴别超声甲状腺成像报告和数据系统(thyroid imaging reporting and data system,TI-RADS)诊断为4A、4B类甲状腺微小结节良恶性的价值。方法回顾性入组2018年1月至2022年1月经过术后病理证实甲状腺结节患者300例(115例良性,185例恶性)。从增强CT图像中提取影像组学特征分别构建动脉期、静脉期、延迟期及多期联合(动脉期+静脉期+延迟期)影像组学模型,联合诊断效能最高的影像组学模型和临床特征构建综合诊断模型并绘制诺莫图。使用接受者工作特征曲线下面积(area under the receiver operating characteristic curve,AUC)评估模型的诊断性能,决策曲线分析(decision curve analysis,DCA)评价模型的临床效用。结果多期联合组学模型的诊断表现(训练集AUC vs测试集AUC:0.814 vs 0.718)优于单一期像组学模型(动脉期:0.730 vs 0.601;静脉期:0.794 vs 0.678;延迟期:0.793 vs 0.622);与临床模型(训练集AUC:0.732;测试集AUC:0.766)和多期联合组学模型相比,综合诊断模型在训练集(AUC:0.876)和测试集(AUC:0.813)均具有更好的诊断表现。决策曲线分析表明,该综合诊断模型具有更高的临床应用价值。结论增强CT影像组学能够在术前有效鉴别TI-RADS 4A和4B类甲状腺微小结节的良恶性。展开更多
基金funded by the Guangdong Major Project of Basic and Applied Basic Research (Grant No.2020B0301030006)。
文摘Adding Ti particles to magnesium alloy simultaneously enhances its strength and ductility.However,how these particles influence on Mg alloy’s corrosion performance is seldom reported.The corrosion behavior of AZ31-Ti composites containing titanium nanoparticles(1.5 and 5 wt%)and micron particles(10 wt%)prepared by powder metallurgical in 3.5 wt%NaCl solution was investigated.The results indicate that Ti particles serve as the primary location for the cathodic hydrogen reduction reaction,resulting in intense galvanic corrosion between the Ti and Mg matrix.Ti nanoparticles distributed at the interface of the original AZ31 powder were in a discontinuous mesh structure,thus failing to act as a barrier against corrosion.The corrosion products with the existence of numerous cracks gradually peel off during the corrosion process and cannot protect the matrix.The average corrosion rate P_(w) of AZ31,AZ31-1.5%Ti,AZ31-5%Ti,and AZ31-10%Ti after 7 days of immersion is 27.55,105.65,283.67,and 99.35 mm/y,respectively.Therefore,AZ31-Ti composites can be considered as potential candidates for degradable fracturing tools.Otherwise,it is recommended to improve their corrosion resistance through surface treatment.
文摘目的探讨基于增强计算机断层扫描(computed tomography,CT)影像组学在鉴别超声甲状腺成像报告和数据系统(thyroid imaging reporting and data system,TI-RADS)诊断为4A、4B类甲状腺微小结节良恶性的价值。方法回顾性入组2018年1月至2022年1月经过术后病理证实甲状腺结节患者300例(115例良性,185例恶性)。从增强CT图像中提取影像组学特征分别构建动脉期、静脉期、延迟期及多期联合(动脉期+静脉期+延迟期)影像组学模型,联合诊断效能最高的影像组学模型和临床特征构建综合诊断模型并绘制诺莫图。使用接受者工作特征曲线下面积(area under the receiver operating characteristic curve,AUC)评估模型的诊断性能,决策曲线分析(decision curve analysis,DCA)评价模型的临床效用。结果多期联合组学模型的诊断表现(训练集AUC vs测试集AUC:0.814 vs 0.718)优于单一期像组学模型(动脉期:0.730 vs 0.601;静脉期:0.794 vs 0.678;延迟期:0.793 vs 0.622);与临床模型(训练集AUC:0.732;测试集AUC:0.766)和多期联合组学模型相比,综合诊断模型在训练集(AUC:0.876)和测试集(AUC:0.813)均具有更好的诊断表现。决策曲线分析表明,该综合诊断模型具有更高的临床应用价值。结论增强CT影像组学能够在术前有效鉴别TI-RADS 4A和4B类甲状腺微小结节的良恶性。
