In this paper,the phenomena of Mg_(2)Sn-induced Sn whisker growth were explored on the surfaces of Mg/Sn/Mg ultrasonic-assisted soldering joints after aging treatment.The in-situ observation and thermal analysis confi...In this paper,the phenomena of Mg_(2)Sn-induced Sn whisker growth were explored on the surfaces of Mg/Sn/Mg ultrasonic-assisted soldering joints after aging treatment.The in-situ observation and thermal analysis confirmed that the formation and the corrosion of Mg_(2)Sn nanoparticles were the dominant reason of Sn whisker growth.The Mg_(2)Sn accumulation at the grain boundaries would pin the dislocation slip and affect the continuity of whisker growth,and the boundary angle would thus play a decisive role in the growth shape of Sn whiskers due to the pining effect of Mg_(2)Sn.This study might be conducive to elucidating the growth behavior of Sn whiskers and provide the exploration strategy to further improve the bonding strength of Mg/Sn/Mg ultrasonic-assisted soldering joints.展开更多
文摘目的构建并验证多灶性甲状腺乳头状癌(multifocal papillary thyroid carcinoma,MPTC)高容量淋巴结转移(high-volume lymph node metastasis,HVM)的列线图预测模型。方法选取2010年1月至2024年1月于杭州市第一人民医院(A中心)及杭州市肿瘤医院(B中心)分别确诊的1146例和234例MPTC患者作为研究对象。A中心患者以7:3的比例采用随机数字表法分成训练集(n=803)和测试集(n=343),B中心34例患者作为外部验证集。通过单因素和多因素Logistic回归分析在训练集中筛选HVM的独立风险因素,并构建列线图预测模型,测试集和外部验证集用以评价模型的泛化能力,通过受试者操作特征曲线下面积(area under the curve,AUC)、敏感度、特异性评价模型的区分能力。结果A中心和B中心发生HVM的概率分别为13.3%和12.8%。单因素及多因素Logistic回归显示,男性(OR=2.91,95%CI:1.835~4.599)、病灶最大径(OR=1.05,95%CI:1.021~1.070)和年龄(OR=0.95,95%CI:0.936~0.972)均为发生HVM的独立风险因素。基于独立风险因素构建列线图预测模型,AUC、敏感度和特异性在训练集中分别为0.767、72.6%和70.2%,在测试集中分别为0.838、94.9%和68.4%,在外部验证集中分别为0.769、63.3%和84.3%。校准曲线显示与理想曲线具有良好的一致性。结论基于临床风险因素构建的预测模型可有效预测MPTC患者发生HVM的概率。
基金supported by Science and Technology Planning Project of Shenzhen (Grant No. JCYJ201908 09161213154)Xiamen Youth Innovation Fund Project (Grant No. 3502Z20206026)Academy-level Project of Xiamen City University (Grant No.KYKJ2019-4)。
文摘In this paper,the phenomena of Mg_(2)Sn-induced Sn whisker growth were explored on the surfaces of Mg/Sn/Mg ultrasonic-assisted soldering joints after aging treatment.The in-situ observation and thermal analysis confirmed that the formation and the corrosion of Mg_(2)Sn nanoparticles were the dominant reason of Sn whisker growth.The Mg_(2)Sn accumulation at the grain boundaries would pin the dislocation slip and affect the continuity of whisker growth,and the boundary angle would thus play a decisive role in the growth shape of Sn whiskers due to the pining effect of Mg_(2)Sn.This study might be conducive to elucidating the growth behavior of Sn whiskers and provide the exploration strategy to further improve the bonding strength of Mg/Sn/Mg ultrasonic-assisted soldering joints.
