在应变速率为0.1、0.01、0.001s^(-1)和变形温度400、450、500℃条件下采用热模拟试验机对Al-11.5Si-1.6Mg-3.5Cu合金进行了等温热压缩试验,并采用动态材料模型(Dynamic Material Modeling, DMM)绘制材料的热加工图,预测了所设计的钎料...在应变速率为0.1、0.01、0.001s^(-1)和变形温度400、450、500℃条件下采用热模拟试验机对Al-11.5Si-1.6Mg-3.5Cu合金进行了等温热压缩试验,并采用动态材料模型(Dynamic Material Modeling, DMM)绘制材料的热加工图,预测了所设计的钎料合金Al-11.5Si-1.6Mg-3.5Cu与芯材铝合金AA3003的变形机制,从而得到钎料合金和芯材合金共同适合的加工窗口,避免复合轧制过程中出现材料开裂、变形不匹配等问题,缩短试验时间。试验结果表明,当变形温度在400~500℃,应变速率范围为0.001s^(-1)~0.1s^(-1),Al-11.5Si-1.6Mg-3.5Cu合金与芯材合金AA3003在高温变形时不会出现失稳现象,并且在较高的温度和较低的应变速率下比较适合材料的成形加工。展开更多
目的探讨超声心动图对原发隔异位(malposition of septum primum,MSP)型肺静脉异位引流的诊断价值。方法回顾分析7名MSP儿童的超声心动图征象,并于CTA和胸外科直视手术结果比较。结果6例(85.7%)超声诊断正确,1例误诊为单心房。1例合并...目的探讨超声心动图对原发隔异位(malposition of septum primum,MSP)型肺静脉异位引流的诊断价值。方法回顾分析7名MSP儿童的超声心动图征象,并于CTA和胸外科直视手术结果比较。结果6例(85.7%)超声诊断正确,1例误诊为单心房。1例合并部分性肺静脉异位引流,6例合并完全性肺静脉异位引流。超声心动图显示所有肺静脉均开口于解剖左房后壁,因原发隔异位导致肺静脉异常引流入右房。剑突下冠状、剑突下矢状、心尖四腔、胸骨旁短轴切面可清晰显示继发隔上边缘带缺如以及原发隔不同程度左移。结论超声心动图作为一种非创伤性的检查手段,能正确诊断原发隔异位,为该病的进一步诊断与治疗提供更多信息。展开更多
心脏的收缩时间间期(Systolic time interval 简称STI)是临床上用以判定心脏功能状态的无创伤性检查方法之一。动物实验研究中的应用尚少。猕猴(Macaca mulatta),的STI未见报导,近年来将猴用于心血管疾病的实验研究逐渐增加,寻求无创伤...心脏的收缩时间间期(Systolic time interval 简称STI)是临床上用以判定心脏功能状态的无创伤性检查方法之一。动物实验研究中的应用尚少。猕猴(Macaca mulatta),的STI未见报导,近年来将猴用于心血管疾病的实验研究逐渐增加,寻求无创伤性心功能检查技术以促进实验研究的发展,已为人们所重视。现将对40例正常猕猴在戊巴比妥钠麻醉下的STI值报告于后。展开更多
Bearing ring is the crucial component of bearing. With regard to such problems as material waste, low efficiency and high energy consumption in current process of producing large bearing ring, a new process named ＂ca...Bearing ring is the crucial component of bearing. With regard to such problems as material waste, low efficiency and high energy consumption in current process of producing large bearing ring, a new process named ＂casting-rolling compound forming technology＂ is researched by taking the typical 42CrMo slew bearing as object. Through theoretical analysis, the design criteria of the main casting-rolling forming parameters are put forward at first. Then the constitutive relationship model of as-cast 42CrMo steel and its mathematical model of dynamic recrystallization are obtained according to the results of the hot compression experiment. By a coupled thermal-mechanical finite element model for radial-axial rolling of bearing ring, the fraction of dynamic recrystallization is calculated and recrystallized grains size are predicated. Meanwhile, the effects of the initial rolling temperature and feed rate of idle roll on material microstructure evolution are analyzed. Finally, the industrial rolling experiment is designed and performed, based on the simulation results. In addition, mechanical and metallographic tests are conducted on rolled bearing ring to get the mechanical parameters and metallographic structure. The experimental data and results show that the mechanical properties of bearing ring produced by casting-rolling compound forming technology are up to industrial standard, and a qualified bearing ring can be successfully formed by employing this new technology. Through the study, a process of forming large bearing ring directly by using casting ring blank is obtained, which could provide an effective theoretical guidance for manufacturing large ring parts. It also has an edge in saving material, lowering energy and improving efficiency.展开更多
Currently,the growing number of end-stage renal disease patients in developing countries consumes a greater proportion of healthcare budget,and increasing attention is being focused on the cost-effectiveness of the pr...Currently,the growing number of end-stage renal disease patients in developing countries consumes a greater proportion of healthcare budget,and increasing attention is being focused on the cost-effectiveness of the procedure.We aimed to assess the cost-effectiveness of living-related renal transplantation (RTx) as compared with that for hemodialysis (HD) and identify medical factors associated with charges for RTx in northwestern China.This study was a retrospective analysis of 372 patients on regular HD and 122 living-related kidney transplant recipients on regular follow-up for at least 3 years in northwestern China.All data on charges included HD procedure,RTx procedure,the cost for donor operation,immunosuppression,and follow-up medicare.The average annual cost to all patients on HD and kidney recipients during the first 3 years after RTx was $14482/$31027,$13502/$11038,and $13382/$10243,respectively.The three variables were found to be significant in predicting increased costs for RTx:diltiazem administration,acute rejection and infection complications.We concluded that from the second year on,RTx in China was more effective and less costly than dialysis treatment,although recipients without diltiazem administration and with acute rejection or infection proved costlier during the first year after transplantation.展开更多
文摘在应变速率为0.1、0.01、0.001s^(-1)和变形温度400、450、500℃条件下采用热模拟试验机对Al-11.5Si-1.6Mg-3.5Cu合金进行了等温热压缩试验,并采用动态材料模型(Dynamic Material Modeling, DMM)绘制材料的热加工图,预测了所设计的钎料合金Al-11.5Si-1.6Mg-3.5Cu与芯材铝合金AA3003的变形机制,从而得到钎料合金和芯材合金共同适合的加工窗口,避免复合轧制过程中出现材料开裂、变形不匹配等问题,缩短试验时间。试验结果表明,当变形温度在400~500℃,应变速率范围为0.001s^(-1)~0.1s^(-1),Al-11.5Si-1.6Mg-3.5Cu合金与芯材合金AA3003在高温变形时不会出现失稳现象,并且在较高的温度和较低的应变速率下比较适合材料的成形加工。
文摘目的探讨超声心动图对原发隔异位(malposition of septum primum,MSP)型肺静脉异位引流的诊断价值。方法回顾分析7名MSP儿童的超声心动图征象,并于CTA和胸外科直视手术结果比较。结果6例(85.7%)超声诊断正确,1例误诊为单心房。1例合并部分性肺静脉异位引流,6例合并完全性肺静脉异位引流。超声心动图显示所有肺静脉均开口于解剖左房后壁,因原发隔异位导致肺静脉异常引流入右房。剑突下冠状、剑突下矢状、心尖四腔、胸骨旁短轴切面可清晰显示继发隔上边缘带缺如以及原发隔不同程度左移。结论超声心动图作为一种非创伤性的检查手段,能正确诊断原发隔异位,为该病的进一步诊断与治疗提供更多信息。
文摘心脏的收缩时间间期(Systolic time interval 简称STI)是临床上用以判定心脏功能状态的无创伤性检查方法之一。动物实验研究中的应用尚少。猕猴(Macaca mulatta),的STI未见报导,近年来将猴用于心血管疾病的实验研究逐渐增加,寻求无创伤性心功能检查技术以促进实验研究的发展,已为人们所重视。现将对40例正常猕猴在戊巴比妥钠麻醉下的STI值报告于后。
基金supported by Key Program of National Natural Science Foundation of China(Grant No.51135007)National Natural Science Foundation of China(Grant No.51075290)
文摘Bearing ring is the crucial component of bearing. With regard to such problems as material waste, low efficiency and high energy consumption in current process of producing large bearing ring, a new process named ＂casting-rolling compound forming technology＂ is researched by taking the typical 42CrMo slew bearing as object. Through theoretical analysis, the design criteria of the main casting-rolling forming parameters are put forward at first. Then the constitutive relationship model of as-cast 42CrMo steel and its mathematical model of dynamic recrystallization are obtained according to the results of the hot compression experiment. By a coupled thermal-mechanical finite element model for radial-axial rolling of bearing ring, the fraction of dynamic recrystallization is calculated and recrystallized grains size are predicated. Meanwhile, the effects of the initial rolling temperature and feed rate of idle roll on material microstructure evolution are analyzed. Finally, the industrial rolling experiment is designed and performed, based on the simulation results. In addition, mechanical and metallographic tests are conducted on rolled bearing ring to get the mechanical parameters and metallographic structure. The experimental data and results show that the mechanical properties of bearing ring produced by casting-rolling compound forming technology are up to industrial standard, and a qualified bearing ring can be successfully formed by employing this new technology. Through the study, a process of forming large bearing ring directly by using casting ring blank is obtained, which could provide an effective theoretical guidance for manufacturing large ring parts. It also has an edge in saving material, lowering energy and improving efficiency.
基金Supported by the Science Foundation of Shaanxi Province (No. SJ08C201)
文摘Currently,the growing number of end-stage renal disease patients in developing countries consumes a greater proportion of healthcare budget,and increasing attention is being focused on the cost-effectiveness of the procedure.We aimed to assess the cost-effectiveness of living-related renal transplantation (RTx) as compared with that for hemodialysis (HD) and identify medical factors associated with charges for RTx in northwestern China.This study was a retrospective analysis of 372 patients on regular HD and 122 living-related kidney transplant recipients on regular follow-up for at least 3 years in northwestern China.All data on charges included HD procedure,RTx procedure,the cost for donor operation,immunosuppression,and follow-up medicare.The average annual cost to all patients on HD and kidney recipients during the first 3 years after RTx was $14482/$31027,$13502/$11038,and $13382/$10243,respectively.The three variables were found to be significant in predicting increased costs for RTx:diltiazem administration,acute rejection and infection complications.We concluded that from the second year on,RTx in China was more effective and less costly than dialysis treatment,although recipients without diltiazem administration and with acute rejection or infection proved costlier during the first year after transplantation.
