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      • KCI등재

        Complex wavelet enhanced shape from shading transform for estimating surface roughness of milled mechanical components

        Sun Weifang,Chen Binqiang,Yao Bin,Cao Xincheng,Feng Wei 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.2

        The metal surface topology contains abundant information related to the health states of the cutting tool as well as the cutting operation. In this paper, we attempt to adopt 2D digital images of the machined metal surface, acquired via non-contact photo-imaging techniques, as the monitoring media. A Wallis filter based dodging algorithm is applied to cure the uneven contrast phenomenon caused by imperfect lighting illumination. 3D digital models were derived and retrieved from the digital image using a wavelet enhanced Shape from shading (SFS) transform. The minimization based SFS is presented to retrieve the 3D digital surface from the milled workpiece. The dual tree complex wavelet transform is adopted to enhance SFS such that the interfering noise can be suppressed. In the end, quantitative surface roughness indicators are utilized to estimate the surface roughness numerically. A milling cutting experiment of aero-material of aluminum alloy 7075 was carried out to verify the effectiveness of the proposed approach. The comparison results demonstrate that the proposed approach was capable of retrieving 3D surfaces of high precision. With the approach, the digital image emerges as a promising vehicle for machining condition monitoring of CNC machines.

      • Crack detection in concrete slabs by graph-based anomalies calculation

        Yuqing Zhou,Weifang Sun,Jiawei Xiang,Binqiang Chen,Wei Feng 국제구조공학회 2022 Smart Structures and Systems, An International Jou Vol.29 No.3

        Concrete slab cracks monitoring of modern high-speed railway is important for safety and reliability of train operation, to prevent catastrophic failure, and to reduce maintenance costs. This paper proposes a curvature filtering improved crack detection method in concrete slabs of high-speed railway via graph-based anomalies calculation. Firstly, large curvature information contained in the images is extracted for the crack identification based on an improved curvature filtering method. Secondly, a graph-based model is developed for the image sub-blocks anomalies calculation where the baseline of the subblocks is acquired by crack-free samples. Once the anomaly is large than the acquired baseline, the sub-block is considered as crack-contained block. The experimental results indicate that the proposed method performs better than convolutional neural network method even under different curvature structures and illumination conditions. This work therefore provides a useful tool for concrete slabs crack detection and is broadly applicable to variety of infrastructure systems.

      • KCI등재

        Synthesis and Antitumor Activity of Novel Diaryl Ether Hydroxamic Acids Derivatives as Potential HDAC Inhibitors

        Yong Zhu,Tao Lu,Xin Chen,Zeng Wu,Yixuan Zheng,Yadong Chen,Weifang Tang 대한약학회 2012 Archives of Pharmacal Research Vol.35 No.10

        A series of diaryl ether hydroxamic acids were synthesized for the first time and evaluated for the HDAC biology and antiproliferative activity. The structures of these new hydroxamic acids derivatives were confirmed by IR, 1H-NMR and mass spectrum. Some of these compounds showed micro molar activity in the HDAC inhibitory assay and against four cancer cell lines.

      • KCI등재

        Remaining useful life prediction of circuit breaker operating mechanisms based on wavelet‑enhanced dual‑tree residual networks

        Tailong Wu,Yuan Yao,Zhihao Li,Binqiang Chen,Yue Wu,Weifang Sun 전력전자학회 2024 JOURNAL OF POWER ELECTRONICS Vol.24 No.1

        The remaining useful life prediction of circuit breaker operating mechanisms is crucial for the condition-based maintenance of national power grids. To realize accurate remaining useful life prediction, a novel wavelet-enhanced dual-tree residual network is proposed in this paper. Through this wavelet transform, the time series is decomposed into two components (high frequency and low frequency). Then the two decomposed components are fed into two lightweight residual neural network structures. By concatenating the dual-tree features, the remaining useful life of a circuit breaker operating mechanism can be predicted. The proposed network is validated using a full-life cycle experiment of the circuit breaker operating mechanism. Results show that the proposed method has good capability when it comes to predicting the remaining useful life of the circuit breaker operating mechanism. Along with application in the construction of smart grids and green energy, it is expected that the proposed method has potential in running state prognostics of circuit breakers.

      • KCI등재

        Investigation on quasi-static and dynamic mechanical properties of disc springs considering asymmetric frictional boundary

        Yanfeng Zhou,Dan Wang,Jianyuan He,Weifang Chen,Rupeng Zhu 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.11

        Systematic experimental studies of disc springs are sparse. In this paper, quasistatic and dynamic compression experiments are performed on a single disc spring under both symmetric and asymmetric frictional conditions for different series of disc springs. On this basis, multiple disc springs stacked in parallel are also investigated. The full-range load-displacement curves of disc springs under quasi-static and dynamic compression are obtained and compared with the theoretical values, and the limitations of the existing analytical solutions are pointed out. The analysis revealed that frictional conditions of contact boundaries greatly affect the damping of disc springs. As the compression frequency increases, the damping of the disc spring gradually increases and finally remains stable. When the disc springs are stacked in parallel, the stiffness relationship can be approximated as conforming to the law of parallel connection, but the damping increases significantly due to the introduction of friction between internal contact surfaces.

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