The thermal deformation behavior of FV520B stainless steel is investigated.Isothermal compression tests were conducted at temperatures ranging from 600 to 900℃ and strain rates from 0.001 to 10 s^(−1).The true stress...The thermal deformation behavior of FV520B stainless steel is investigated.Isothermal compression tests were conducted at temperatures ranging from 600 to 900℃ and strain rates from 0.001 to 10 s^(−1).The true stress–strain curves were corrected for friction and temperature due to the drum shape and adiabatic heating.The comparison shows that there is a large difference between the stress before and after the correction,which proves that the correction is necessary.Five constitutive models were developed:the original Arrhenius model,the strain correction Arrhenius model,a new modified Arrhenius model,the back propagation neural network model(BPNN)and the dandelion optimization BPNN model(DO-BPNN).The DO-BPNN model showed the highest prediction accuracy though it was more computationally intensive than the other models.The new modified Arrhenius model performed a better predictive capacity than the strain correction version,while it showed a negligible increase in the number of parameters and computational time.Although artificial neural network-based models exhibit superior accuracy compared to the Arrhenius models,their application in finite element simulations still faces notable challenges.展开更多
目的研究miR-21在弥漫大B细胞淋巴瘤(diffuse large B-cell lymphoma,DLBCL)中的表达,探讨miR-21表达与DL-BCL临床病理特征的关系及其在DLBCL发生发展中的意义。方法采用Real-time RT-PCR方法检测36例DLBCL和10例正常淋巴结中miR-21的表...目的研究miR-21在弥漫大B细胞淋巴瘤(diffuse large B-cell lymphoma,DLBCL)中的表达,探讨miR-21表达与DL-BCL临床病理特征的关系及其在DLBCL发生发展中的意义。方法采用Real-time RT-PCR方法检测36例DLBCL和10例正常淋巴结中miR-21的表达,并采用免疫组织化学SP法检测Ki-67、PTEN在DLBCL中的表达。结果miR-21在DLBCL中高表达,36例DLBCL中有14例表达PTEN(38.9%),21例Ki-67≥50%(58.3%)。DLBCL中miR-21表达水平与PTEN蛋白表达呈负相关,其高表达与DLBCL高Ann Arbor分期、高增殖指数(Ki-67≥50%)、国际预后指数(IPI)呈正相关。结论miR-21过表达可能是DLBCL恶性度高的标志,是促进DLBCL肿瘤细胞增殖的重要因素。PTEN可能是miR-21在DLBCL发挥作用的靶标。展开更多
基金supported by the National Natural Science Foundation of China(Grant No.52275373)the National Natural Science Foundation of China(Grant No.52105397)the Open Foundation of National Key Laboratory of Metal Forming Technology and Heavy Equipment(Grant No.S2308100.W08).
文摘The thermal deformation behavior of FV520B stainless steel is investigated.Isothermal compression tests were conducted at temperatures ranging from 600 to 900℃ and strain rates from 0.001 to 10 s^(−1).The true stress–strain curves were corrected for friction and temperature due to the drum shape and adiabatic heating.The comparison shows that there is a large difference between the stress before and after the correction,which proves that the correction is necessary.Five constitutive models were developed:the original Arrhenius model,the strain correction Arrhenius model,a new modified Arrhenius model,the back propagation neural network model(BPNN)and the dandelion optimization BPNN model(DO-BPNN).The DO-BPNN model showed the highest prediction accuracy though it was more computationally intensive than the other models.The new modified Arrhenius model performed a better predictive capacity than the strain correction version,while it showed a negligible increase in the number of parameters and computational time.Although artificial neural network-based models exhibit superior accuracy compared to the Arrhenius models,their application in finite element simulations still faces notable challenges.
