为了探究高速空气燃料热喷涂(activated combustion-high velocity air fuel,AC-HVAF)过程中喷涂粒子撞击基材后的沉积特性。采用AC-HVAF热喷涂技术在AZ80镁合金基体上沉积WC-10Co-4Cr硬质涂层。通过离散沉积实验获得薄层沉积粒子,探讨...为了探究高速空气燃料热喷涂(activated combustion-high velocity air fuel,AC-HVAF)过程中喷涂粒子撞击基材后的沉积特性。采用AC-HVAF热喷涂技术在AZ80镁合金基体上沉积WC-10Co-4Cr硬质涂层。通过离散沉积实验获得薄层沉积粒子,探讨各种沉积形貌的种类、形成原因、结合机制及射流中粒子的径向和轴向分布。结果表明:在AC-HVAF粒子沉积过程中,嵌入型沉积为主要的沉积形貌,同时包含少量的破碎型与空腔型沉积粒子。在涂层的形成过程中,嵌入型沉积对涂层/基体结合性能起重要作用;空腔型沉积的小颗粒及破碎型沉积的大颗粒是造成沉积效率下降的主要原因。喷涂粒子主要集中在射流中心,越靠近射流边缘,空腔型沉积粒子越多,最终导致AC-HVAF粒子射流呈现出空间分布特征。展开更多
该文利用冷金属过渡(Cold metal transfer,CMT)技术,使用电弧丝材增材制造系统制造2Cr13马氏体不锈钢单道多层薄壁试样,并研究了不同层间温度(100℃,150℃和200℃)对薄壁试样表面成形,微观组织和力学性能的影响。研究结果表明,较高的层...该文利用冷金属过渡(Cold metal transfer,CMT)技术,使用电弧丝材增材制造系统制造2Cr13马氏体不锈钢单道多层薄壁试样,并研究了不同层间温度(100℃,150℃和200℃)对薄壁试样表面成形,微观组织和力学性能的影响。研究结果表明,较高的层间温度会使得薄壁成形件整体温度升高,散热状况变差,熔池高温存在时间增长,熔融金属流动性增强,最终导致成形件表面变差甚至塌陷。成形件中部组织在经历反复加热和冷却过程后,主要由极为细长的板条马氏体组成,并伴有少量铁素体以及沿铁素体晶界析出的碳化物。靠近重熔区位置由于熔池的热作用会导致马氏体组织过热而发生相变,形成密集的铁素体。随着层间温度减小,成形件晶粒尺寸和分布更为细小均匀;另外,弥散分布在铁素体晶界上的碳化物阻碍位错运动,两者的共同作用使得显微硬度和抗拉强度随层间温度降低而升高,同时拉伸试样的断后伸长率也随之增大。拉伸断裂形式均为韧性断裂,随着层间温度的减小,同取样方向上拉伸试样断口尺寸越来越大,韧窝也越来越深。展开更多
BACKGROUND Retinopathy is the most common microvascular disease of type 2 diabetes,and seriously threatens the life,health and quality of life of patients.It is worth noting that the development of diabetic retinopath...BACKGROUND Retinopathy is the most common microvascular disease of type 2 diabetes,and seriously threatens the life,health and quality of life of patients.It is worth noting that the development of diabetic retinopathy(DR)can be hidden,with few symptoms.Therefore,the preliminary screening of diabetic patients should identify DR as soon as possible,delay disease progression,and play a vital role in its diagnosis and treatment.AIM To investigate the correlation between glycated hemoglobin A1c(HbA1c),urinary microalbumin(U-mALB),urinary creatinine(U-CR),mALB/U-CR ratio,β2 microglobulin(β2MG),retinol binding protein(RBP)and DR.METHODS A total of 180 patients with type 2 diabetes mellitus attending the Second People’s Hospital of Hefei from January 2022 to August 2022 were retrospectively enrolled by ophthalmologists.Based on whether they had combined retinopathy and its degree,68 patients with diabetes mellitus without retinopathy(NDR)were assigned to the NDR group,54 patients with non-proliferative DR(NPDR)to the NPDR group,and 58 patients with proliferative DR to the PDR group.General data,and HbA1c,mALB,β2MG,RBP,mALB/U-CR and U-CR results were collected from the patients and compared among the groups.Pearson's correlation method was used to analyze the correlation between HbA1c,mALB,β2MG,RBP,mALB/U-CR and U-CR indices,and multiple linear regression was applied to identify the risk factors for DR.Receiver operator characteristic(ROC)curves were also drawn.RESULTS The differences in age,gender,systolic and diastolic blood pressure between the groups were not statistically significantly(P>0.05),but the difference in disease duration was statistically significant(P<0.05).The differences in fasting blood glucose,high-density lipoprotein cholesterol,low-density lipoprotein cholesterol,total cholesterol,and triglyceride between the groups were not statistically significant(P>0.05).HbA1c in the PDR group was higher than that in the NPDR and NDR groups(P<0.05).The levels of mALB,β2MG,RBP,mALB/U-CR and UCR in the PDR group were higher than those in the NPDR and NDR groups(P<0.05).Multiple linear regression analysis showed that disease duration,HbA1c,mALB,β2MG,RBP,mALB/U-CR and U-CR were risk factors for the development of DR.The ROC curve showed that the area under the curve(AUC)for the combination of indices(HbA1c+mALB+mALB/U-CR+U-CR+β2MG+RBP)was 0.958,with a sensitivity of 94.83%and specificity of 96.72%,which was higher than the AUC for single index prediction(P<0.05).CONCLUSION HbA1c,mALB,mALB/U-CR,U-CR,β2MG and RBP can reflect the development of DR and are risk factors affecting PDR,and the combination of these six indices has predictive value for PDR.展开更多
文摘为了探究高速空气燃料热喷涂(activated combustion-high velocity air fuel,AC-HVAF)过程中喷涂粒子撞击基材后的沉积特性。采用AC-HVAF热喷涂技术在AZ80镁合金基体上沉积WC-10Co-4Cr硬质涂层。通过离散沉积实验获得薄层沉积粒子,探讨各种沉积形貌的种类、形成原因、结合机制及射流中粒子的径向和轴向分布。结果表明:在AC-HVAF粒子沉积过程中,嵌入型沉积为主要的沉积形貌,同时包含少量的破碎型与空腔型沉积粒子。在涂层的形成过程中,嵌入型沉积对涂层/基体结合性能起重要作用;空腔型沉积的小颗粒及破碎型沉积的大颗粒是造成沉积效率下降的主要原因。喷涂粒子主要集中在射流中心,越靠近射流边缘,空腔型沉积粒子越多,最终导致AC-HVAF粒子射流呈现出空间分布特征。
文摘该文利用冷金属过渡(Cold metal transfer,CMT)技术,使用电弧丝材增材制造系统制造2Cr13马氏体不锈钢单道多层薄壁试样,并研究了不同层间温度(100℃,150℃和200℃)对薄壁试样表面成形,微观组织和力学性能的影响。研究结果表明,较高的层间温度会使得薄壁成形件整体温度升高,散热状况变差,熔池高温存在时间增长,熔融金属流动性增强,最终导致成形件表面变差甚至塌陷。成形件中部组织在经历反复加热和冷却过程后,主要由极为细长的板条马氏体组成,并伴有少量铁素体以及沿铁素体晶界析出的碳化物。靠近重熔区位置由于熔池的热作用会导致马氏体组织过热而发生相变,形成密集的铁素体。随着层间温度减小,成形件晶粒尺寸和分布更为细小均匀;另外,弥散分布在铁素体晶界上的碳化物阻碍位错运动,两者的共同作用使得显微硬度和抗拉强度随层间温度降低而升高,同时拉伸试样的断后伸长率也随之增大。拉伸断裂形式均为韧性断裂,随着层间温度的减小,同取样方向上拉伸试样断口尺寸越来越大,韧窝也越来越深。
文摘BACKGROUND Retinopathy is the most common microvascular disease of type 2 diabetes,and seriously threatens the life,health and quality of life of patients.It is worth noting that the development of diabetic retinopathy(DR)can be hidden,with few symptoms.Therefore,the preliminary screening of diabetic patients should identify DR as soon as possible,delay disease progression,and play a vital role in its diagnosis and treatment.AIM To investigate the correlation between glycated hemoglobin A1c(HbA1c),urinary microalbumin(U-mALB),urinary creatinine(U-CR),mALB/U-CR ratio,β2 microglobulin(β2MG),retinol binding protein(RBP)and DR.METHODS A total of 180 patients with type 2 diabetes mellitus attending the Second People’s Hospital of Hefei from January 2022 to August 2022 were retrospectively enrolled by ophthalmologists.Based on whether they had combined retinopathy and its degree,68 patients with diabetes mellitus without retinopathy(NDR)were assigned to the NDR group,54 patients with non-proliferative DR(NPDR)to the NPDR group,and 58 patients with proliferative DR to the PDR group.General data,and HbA1c,mALB,β2MG,RBP,mALB/U-CR and U-CR results were collected from the patients and compared among the groups.Pearson's correlation method was used to analyze the correlation between HbA1c,mALB,β2MG,RBP,mALB/U-CR and U-CR indices,and multiple linear regression was applied to identify the risk factors for DR.Receiver operator characteristic(ROC)curves were also drawn.RESULTS The differences in age,gender,systolic and diastolic blood pressure between the groups were not statistically significantly(P>0.05),but the difference in disease duration was statistically significant(P<0.05).The differences in fasting blood glucose,high-density lipoprotein cholesterol,low-density lipoprotein cholesterol,total cholesterol,and triglyceride between the groups were not statistically significant(P>0.05).HbA1c in the PDR group was higher than that in the NPDR and NDR groups(P<0.05).The levels of mALB,β2MG,RBP,mALB/U-CR and UCR in the PDR group were higher than those in the NPDR and NDR groups(P<0.05).Multiple linear regression analysis showed that disease duration,HbA1c,mALB,β2MG,RBP,mALB/U-CR and U-CR were risk factors for the development of DR.The ROC curve showed that the area under the curve(AUC)for the combination of indices(HbA1c+mALB+mALB/U-CR+U-CR+β2MG+RBP)was 0.958,with a sensitivity of 94.83%and specificity of 96.72%,which was higher than the AUC for single index prediction(P<0.05).CONCLUSION HbA1c,mALB,mALB/U-CR,U-CR,β2MG and RBP can reflect the development of DR and are risk factors affecting PDR,and the combination of these six indices has predictive value for PDR.
