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Your search keyword '"Du, Keqin"' showing total 14 results
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14 results on '"Du, Keqin"'

7. Corrosion and conductivity properties of Ni–P/Ti4O7 coating on carbon steel as bipolar plates for proton exchange membrane fuel cells.

Author

Yu, Haiqiang, Guo, Quanzhong, Du, Keqin, Li, Dongyun, Wang, Chuan, and Wang, Yong

Subjects
ALLOY plating, PROTON exchange membrane fuel cells, COMPOSITE coating, CARBON steel, IRON & steel plates, SURFACE coatings, ELECTROLESS plating, INTERFACIAL resistance
Abstract

Purpose: The purpose of this paper is to investigate the interfacial conductivity and corrosion resistance of the Ni–P/Ti4O7 composite coating that is deposited on a carbon steel substrate as bipolar plates for proton exchange membrane fuel cells. Design/methodology/approach: The Ni–P/Ti4O7 coating was prepared by electroless plating. Scanning electron microscopy, white light interference, energy dispersive spectrometry and X-ray diffraction were used, respectively, to study the surface morphology, chemical composition and phase composition of coated samples. Electrochemical impedance spectroscopy, potentiodynamic and potentiostatic polarization were used to test the electrochemical performance and corrosion behavior. The interfacial contact resistance (ICR) was measured via the standard method. Findings: The surface of the Ni–P/Ti4O7 coating is complete and dense and without obvious defects. The electrochemical test results show that the Ni–P/Ti4O7 coating provides better corrosion resistance than the Ni–P coating and substrate. Compared with the Ni–P coating, the ICR of the Ni–P/Ti4O7 coating is lower by about 82.7%. This is because the coating has more conductive contact points. The more exciting thing is that the ICR of the Ni–P/Ti4O7 coating only increases to 12.38 mΩ·cm2 after 5 h of polarization. Originality/value: This paper provides a method for achieving surface modification of metal bipolar plates. Introducing Ti4O7 particles in the Ni–P layer reduces the contact resistance before and after polarization while ensuring good corrosion resistance. [ABSTRACT FROM AUTHOR]

Published
2022
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9. A Digital Compressed Sensing-Based Energy-Efficient Single-Spot Bluetooth ECG Node

Author

Du Keqin, Jianqing Li, Xiangyu Zhang, Zhipeng Cai, Fumin Zou, and Kan Luo

Subjects
lcsh:Medical technology, Article Subject, Computer science, 0206 medical engineering, Real-time computing, Biomedical Engineering, Health Informatics, 02 engineering and technology, law.invention, Bluetooth, law, 0202 electrical engineering, electronic engineering, information engineering, Discrete cosine transform, Wireless, Humans, lcsh:R5-920, business.industry, Node (networking), 020206 networking & telecommunications, Signal Processing, Computer-Assisted, Energy consumption, Equipment Design, 020601 biomedical engineering, Compressed sensing, lcsh:R855-855.5, Electrocardiography, Ambulatory, Surgery, business, lcsh:Medicine (General), Wireless Technology, Algorithms, Biotechnology, Efficient energy use, Data compression, Research Article
Abstract

Energy efficiency is still the obstacle for long-term real-time wireless ECG monitoring. In this paper, a digital compressed sensing- (CS-) based single-spot Bluetooth ECG node is proposed to deal with the challenge in wireless ECG application. A periodic sleep/wake-up scheme and a CS-based compression algorithm are implemented in a node, which consists of ultra-low-power analog front-end, microcontroller, Bluetooth 4.0 communication module, and so forth. The efficiency improvement and the node’s specifics are evidenced by the experiments using the ECG signals sampled by the proposed node under daily activities of lay, sit, stand, walk, and run. Under using sparse binary matrix (SBM), block sparse Bayesian learning (BSBL) method, and discrete cosine transform (DCT) basis, all ECG signals were essentially undistorted recovered with root-mean-square differences (PRDs) which are less than 6%. The proposed sleep/wake-up scheme and data compression can reduce the airtime over energy-hungry wireless links, the energy consumption of proposed node is 6.53 mJ, and the energy consumption of radio decreases 77.37%. Moreover, the energy consumption increase caused by CS code execution is negligible, which is 1.3% of the total energy consumption.

Published
2018

10. A modified frequency slice wavelet transform for physiological signal time-frequency analysis

Author

Zhipeng Cai, Du Keqin, Jianqing Li, Alfred Cuschieri, Zhigang Wang, and Kan Luo

Subjects
Signal processing, Computer science, 0206 medical engineering, Wavelet transform, 02 engineering and technology, Function (mathematics), 020601 biomedical engineering, Signal, Time–frequency analysis, 020303 mechanical engineering & transports, 0203 mechanical engineering, Frequency domain, Spectrogram, Algorithm
Abstract

As a new signal processing tool, a Modified frequency slice wavelet transform (MFSWT) is proposed for physiological signal time-frequency analysis in this study. The transform generates time-frequency representation from the frequency domain, and the reconstruction is independent of frequency slice function (FSF). To realize accurate time-frequency location of signal components, a bound signal-adaptive FSF was introduced to serve as a dynamic frequency filter for the transform. This method avoids troublesome parameter selection, is signal-adaptive and easy to use. The results of two case studies demonstrate the validity of the proposed method, which has good interpretability with high time-frequency resolution, and hence has significant potential for bio-signal time-frequency analysis.

Published
2017

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