In this work,the effect of ultrasonic vibration modes on the mechanical properties and relaxation of residual stress in 6061-T6 aluminum alloy was studied.A new ultrasonic vibration Johnson-Cook model was proposed,and...In this work,the effect of ultrasonic vibration modes on the mechanical properties and relaxation of residual stress in 6061-T6 aluminum alloy was studied.A new ultrasonic vibration Johnson-Cook model was proposed,and the relaxation and distribution of residual stress under ultrasonic vibration were predicted and analyzed using the finite element method(FEM).The mechanical properties of 6061-T6 aluminum alloy under different ultrasonic vibration modes were analyzed through experiments involving notched specimen tensile testing and scanning electron microscopy(SEM)analysis.The findings indicate that ultrasonic vibration treatment during deformation,unloading,and load-holding,as well as treatment with its natural ultrasonic frequency,can effectively release residual stress;however,treatment with its natural frequency has the highest rate of release up to 65.4%.Ultrasonic vibration treatment during deformation better inhibits fracture under the same conditions.The FEM results are in good agreement with the experimental results,and it can be used as a valid tool for predicting residual stress release under ultrasonic vibration.展开更多
Nowadays, the switchable matrix is widely used in China's mine video monitoring technology. This kind of video monitoring ability is weak, easy to produce discrete phenomenon, and the overall quality is poor, the ...Nowadays, the switchable matrix is widely used in China's mine video monitoring technology. This kind of video monitoring ability is weak, easy to produce discrete phenomenon, and the overall quality is poor, the relevance cannot meet the relevant demand standards. Therefore, in order to avoid the real-time monitoring technology of the mine, the relevant designers integrate a 3D video fusion method, which fuses the video picture with the scene model in the mine. On this basis, combined with various kinds of information technology to enhance its own performance, so we developed a real-time monitoring system combined with three-dimensional video, which integrated monitoring and management of the original fragmented lens on the basis of time and space, and dynamically managed its mine content.展开更多
AIM:To investigate the value of optical coherence tomography angiography(OCTA)indicators in the diagnosis of diabetic retinopathy(DR),and to provide patients with diabetic nephropathy(DN)with more sensitive OCTA scree...AIM:To investigate the value of optical coherence tomography angiography(OCTA)indicators in the diagnosis of diabetic retinopathy(DR),and to provide patients with diabetic nephropathy(DN)with more sensitive OCTA screening indicators to detect concurrent DR at an early stage.METHODS:A total of 200 patients who treated in the ophthalmology department of the Seventh Affiliated Hospital,Sun Yat-sen University from 2022 to 2023 were included,including 95 first-diagnosed DR patients and 105 patients without DR,and all patients underwent OCTA examination and a collection of demographics and renal function parameters.After a quality check,automated measurements of the foveal avascular zone area,vessel density(VD),and perfusion density(PD)of both 3 mm×3 mm and 6 mm×6 mm windows were obtained.RESULTS:Using random forest and multivariate Logistic regression methods,we developed a diagnostic model for DR based on 12 variables(age,FBG,SBP,DBP,HbA1c,ALT,ALP,urea/Scr,DM duration,HUA,DN,and CMT).Adding specific OCTA parameters enhanced the efficacy of the existing diagnostic model for DR(outer vessel density in 6 mm×6 mm window,AUC=0.837 vs 0.819,P=0.03).In the study of DN patients,the parameters in the 6 mm×6 mm window improved the diagnostic efficacy of DR(inner VD;outer VD;full VD;outer PD;full PD).CONCLUSION:The outer VD in the 6 mm×6 mm window can enhance the efficacy of the traditional DR diagnostic model.Meanwhile,compared with the 3 mm×3 mm window,the microvascular parameters in the 6 mm×6 mm window focusing on DN patients can be more sensitive to diagnosing the occurrence of DR.展开更多
基金Project(51775480)supported by the National Natural Science Foundation of ChinaProjects(E2018203143,E2022203050)supported by the Natural Science Foundation of Hebei Province,China。
文摘In this work,the effect of ultrasonic vibration modes on the mechanical properties and relaxation of residual stress in 6061-T6 aluminum alloy was studied.A new ultrasonic vibration Johnson-Cook model was proposed,and the relaxation and distribution of residual stress under ultrasonic vibration were predicted and analyzed using the finite element method(FEM).The mechanical properties of 6061-T6 aluminum alloy under different ultrasonic vibration modes were analyzed through experiments involving notched specimen tensile testing and scanning electron microscopy(SEM)analysis.The findings indicate that ultrasonic vibration treatment during deformation,unloading,and load-holding,as well as treatment with its natural ultrasonic frequency,can effectively release residual stress;however,treatment with its natural frequency has the highest rate of release up to 65.4%.Ultrasonic vibration treatment during deformation better inhibits fracture under the same conditions.The FEM results are in good agreement with the experimental results,and it can be used as a valid tool for predicting residual stress release under ultrasonic vibration.
文摘目的探讨基于乳腺X线摄影及动态增强磁共振成像(dynamic contrast-enhanced magnetic resonance imaging,DCE-MRI)的机器学习模型预测乳腺癌患者新辅助治疗(neoadjuvant therapy,NAT)后病理完全缓解(pathological complete response,pCR)的价值。方法回顾性分析2016年8月至2023年7月于青岛大学附属医院(机构1)及烟台毓璜顶医院(机构2)接受NAT后行手术的396例乳腺癌患者资料,来自机构1的320例患者按7∶3比例随机分为训练集和验证集,来自机构2的76例患者作为独立的外部验证集。对患者NAT前乳腺X线摄影及DCE-MRI图像进行感兴趣区域(region of interest,ROI)勾画、特征提取、特征筛选,使用支持向量机(support vector machine,SVM)机器学习算法构建影像组学模型。对临床特征进行单因素-多因素逻辑回归分析,保留具有统计学意义的临床独立预测因子并构建临床模型。将联合影像组学模型与临床独立预测因子使用SVM机器学习算法联合构建综合模型。采用受试者工作特征(receiver operating characteristic,ROC)曲线的曲线下面积(area under the curves,AUC)、准确性、敏感性、特异性和F1-score评价模型的性能,绘制校准曲线评价模型的拟合优度,采用决策曲线分析(decision curve analysis,DCA)评估模型的临床应用价值。结果联合影像组学模型预测性能高于临床模型、乳腺X线摄影影像组学模型和MRI影像组学模型,其在训练集、验证集和外部验证集AUC分别为0.899、0.850及0.765。综合模型预测性能最佳,其在训练集、验证集和外部验证集AUC分别为0.918、0.856、0.795,且该模型具有良好的校准能力和临床收益。Delong检验示临床模型与综合模型的AUC的差异有统计学意义(P<0.05)。结论基于乳腺X线摄影及DCE-MRI的机器学习模型可以预测乳腺癌患者NAT后pCR,且具有较高的预测性能。
文摘Nowadays, the switchable matrix is widely used in China's mine video monitoring technology. This kind of video monitoring ability is weak, easy to produce discrete phenomenon, and the overall quality is poor, the relevance cannot meet the relevant demand standards. Therefore, in order to avoid the real-time monitoring technology of the mine, the relevant designers integrate a 3D video fusion method, which fuses the video picture with the scene model in the mine. On this basis, combined with various kinds of information technology to enhance its own performance, so we developed a real-time monitoring system combined with three-dimensional video, which integrated monitoring and management of the original fragmented lens on the basis of time and space, and dynamically managed its mine content.
文摘AIM:To investigate the value of optical coherence tomography angiography(OCTA)indicators in the diagnosis of diabetic retinopathy(DR),and to provide patients with diabetic nephropathy(DN)with more sensitive OCTA screening indicators to detect concurrent DR at an early stage.METHODS:A total of 200 patients who treated in the ophthalmology department of the Seventh Affiliated Hospital,Sun Yat-sen University from 2022 to 2023 were included,including 95 first-diagnosed DR patients and 105 patients without DR,and all patients underwent OCTA examination and a collection of demographics and renal function parameters.After a quality check,automated measurements of the foveal avascular zone area,vessel density(VD),and perfusion density(PD)of both 3 mm×3 mm and 6 mm×6 mm windows were obtained.RESULTS:Using random forest and multivariate Logistic regression methods,we developed a diagnostic model for DR based on 12 variables(age,FBG,SBP,DBP,HbA1c,ALT,ALP,urea/Scr,DM duration,HUA,DN,and CMT).Adding specific OCTA parameters enhanced the efficacy of the existing diagnostic model for DR(outer vessel density in 6 mm×6 mm window,AUC=0.837 vs 0.819,P=0.03).In the study of DN patients,the parameters in the 6 mm×6 mm window improved the diagnostic efficacy of DR(inner VD;outer VD;full VD;outer PD;full PD).CONCLUSION:The outer VD in the 6 mm×6 mm window can enhance the efficacy of the traditional DR diagnostic model.Meanwhile,compared with the 3 mm×3 mm window,the microvascular parameters in the 6 mm×6 mm window focusing on DN patients can be more sensitive to diagnosing the occurrence of DR.
