Weak feature extraction is of great importance for condition monitoring and intelligent diagnosis of aeroengine.Aimed at achieving intelligent diagnosis of aero-engine main shaft bearing,an enhanced sparsity-assisted ...Weak feature extraction is of great importance for condition monitoring and intelligent diagnosis of aeroengine.Aimed at achieving intelligent diagnosis of aero-engine main shaft bearing,an enhanced sparsity-assisted intelligent condition monitoring method is proposed in this paper.Through analyzing the weakness of convex sparse model,i.e.the tradeoff between noise reduction and feature reconstruction,this paper proposes an enhanced-sparsity nonconvex regularized convex model based on Moreau envelope to achieve weak feature extraction.Accordingly,a sparsity-assisted deep convolutional variational autoencoders network is proposed,which achieves the intelligent identification of fault state through training denoised normal data.Finally,the effectiveness of the proposed method is verified through aero-engine bearing run-to-failure experiment.The comparison results show that the proposed method is good at abnormal pattern recognition,showing a good potential for weak fault intelligent diagnosis of aero-engine main shaft bearings.展开更多
At present, the main method of finite element on the uncoiling machine main shaft or segment rate analysis is simplified equivalent to a separate analysis of various conditions, but this method is comparatively large ...At present, the main method of finite element on the uncoiling machine main shaft or segment rate analysis is simplified equivalent to a separate analysis of various conditions, but this method is comparatively large difference with the actual working condition. In order to make the uncoiler finite element analysis of main shaft and the segment rate conforms to the actual working condition, the paper puts forward a new kind of decoiler assembly finite element analysis method, mainly introduced with Workbench 13.0 on main shaft and segment flate assembly process analysis of statics. The simulation results show that, all parts of the strength and stiffness meet the design requirements. Application results show that this method needs not to simplify the equivalent under various working conditions, it can convenient to get to the main shaft and segment the figure of total deformation and von-Mises stress map and it also improves the analysis efficiency and more accord with the actual working condition.展开更多
Objective To evaluate a very long-term clinical outcomes of patients treated with coronary artery bypass grafting(CABG) and percutaneous coronary intervention(PCI) with drug-eluting stents(DES) for ostial/shaft lesion...Objective To evaluate a very long-term clinical outcomes of patients treated with coronary artery bypass grafting(CABG) and percutaneous coronary intervention(PCI) with drug-eluting stents(DES) for ostial/shaft lesions in unprotected left main coronary artery(ULMCA). Methods & Results A total of 472 patients with isolated ostial/shaft lesions in ULMCA were enrolled, who received DES implantation or underwent CABG between January 2003 and July 2009 in Beijing Anzhen Hospital. The major endpoints of this study were death, repeat revascularization, non-procedural myocardial infarction(MI) and stroke. The median follow-up was twelve years(interquartile range: 9.4–14.0 years) in the overall patients. There were no significant differences of incidence of death(23.3% vs. 25.6%, P = 0.227), repeat revascularization(27.3% vs. 28.4%, P = 0.423), non-procedural MI(20.0% vs. 14.5%, P = 0.561), and stroke(6.1% vs. 9.3%, P = 0.255) between PCI and CABG groups before multivariate adjusting. After adjusting covariates with multivariate Cox hazard regression model, there were still no significant differences between PCI and CABG groups. Conclusions During the median follow-up of twelve years, we found that PCI with DES was as effective and safe as CABG in patients with left main ostial/shaft lesion in this observational study.展开更多
基金the National Natural Science Foundations of China(Nos.91860125,51705398)the National Key Basic Research Program of China(No.2015CB057400)the Shaanxi Province 2020 Natural Science Basic Research Plan(No.2020JQ-042).
文摘Weak feature extraction is of great importance for condition monitoring and intelligent diagnosis of aeroengine.Aimed at achieving intelligent diagnosis of aero-engine main shaft bearing,an enhanced sparsity-assisted intelligent condition monitoring method is proposed in this paper.Through analyzing the weakness of convex sparse model,i.e.the tradeoff between noise reduction and feature reconstruction,this paper proposes an enhanced-sparsity nonconvex regularized convex model based on Moreau envelope to achieve weak feature extraction.Accordingly,a sparsity-assisted deep convolutional variational autoencoders network is proposed,which achieves the intelligent identification of fault state through training denoised normal data.Finally,the effectiveness of the proposed method is verified through aero-engine bearing run-to-failure experiment.The comparison results show that the proposed method is good at abnormal pattern recognition,showing a good potential for weak fault intelligent diagnosis of aero-engine main shaft bearings.
文摘At present, the main method of finite element on the uncoiling machine main shaft or segment rate analysis is simplified equivalent to a separate analysis of various conditions, but this method is comparatively large difference with the actual working condition. In order to make the uncoiler finite element analysis of main shaft and the segment rate conforms to the actual working condition, the paper puts forward a new kind of decoiler assembly finite element analysis method, mainly introduced with Workbench 13.0 on main shaft and segment flate assembly process analysis of statics. The simulation results show that, all parts of the strength and stiffness meet the design requirements. Application results show that this method needs not to simplify the equivalent under various working conditions, it can convenient to get to the main shaft and segment the figure of total deformation and von-Mises stress map and it also improves the analysis efficiency and more accord with the actual working condition.
文摘Objective To evaluate a very long-term clinical outcomes of patients treated with coronary artery bypass grafting(CABG) and percutaneous coronary intervention(PCI) with drug-eluting stents(DES) for ostial/shaft lesions in unprotected left main coronary artery(ULMCA). Methods & Results A total of 472 patients with isolated ostial/shaft lesions in ULMCA were enrolled, who received DES implantation or underwent CABG between January 2003 and July 2009 in Beijing Anzhen Hospital. The major endpoints of this study were death, repeat revascularization, non-procedural myocardial infarction(MI) and stroke. The median follow-up was twelve years(interquartile range: 9.4–14.0 years) in the overall patients. There were no significant differences of incidence of death(23.3% vs. 25.6%, P = 0.227), repeat revascularization(27.3% vs. 28.4%, P = 0.423), non-procedural MI(20.0% vs. 14.5%, P = 0.561), and stroke(6.1% vs. 9.3%, P = 0.255) between PCI and CABG groups before multivariate adjusting. After adjusting covariates with multivariate Cox hazard regression model, there were still no significant differences between PCI and CABG groups. Conclusions During the median follow-up of twelve years, we found that PCI with DES was as effective and safe as CABG in patients with left main ostial/shaft lesion in this observational study.
