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Reliability Analysis of Electromechanical Systems with Degraded Components Containing Multiple Performance Parameters

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Chinese Journal of Mechanical Engineering 2010年第4期23卷 511-516页

作者： li Chunyang chen xun YI Xiaoshan College of Mechatronics and Automation National University of Defense Technology Changsha 410073 China

Components of electromechanical systems usually contain multiple performance parameters and degrade over time. In previous studies, the reliability of these electromechanical systems was analyzed by the traditional method, and the system reliability was estimated based on the reliability of components and the structures of the systems. The system reliability estimated by the traditional method could not reflect the performance of the systems. A new method is proposed in this paper to analyze the system reliability according to the data of multiple performance degraded processes of components. The performance distribution of a degraded component is obtained by the performance degradation analysis, and then states of the component are defined and corresponding state probabilities are estimated. The universal generating function method is proposed and extended to compute the performance distribution and reliability of the system based on the performances of components. A numerical example illustrates the proposed method. The results of the example show that the proposed method can relate the performance of the system to the performances of components and absolutely reflect the relationship between reliability and performance. Compared with the exact values of the system reliability, the results obtained by the proposed method is almost the same with the exact values, and the results obtained by the traditional method are conservative. The proposed method overcomes the shortcomings of the traditional method and provides a new approach to analyze the reliability of electromechanical systems with degraded components containing multiple performance parameters.

关键词： electromechanical system degradation reliability analysis multi-state system universal generating function

Influence factors for successful corneal donation among Chinese adults: data from Nanjing between 2001 and 2012

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International Journal of Ophthalmology(English edition) 2014年第6期7卷 984-987页

作者： li-xun chen Qing-Huai liu Department of Ophthalmology Nanjing First HospitalNanjing Medical University Department of Ophthalmology the First Affiliated Hospital of Nanjing Medical University

AIM: To investigate the factors that may influence the successful corneal donation among adults in ***: This retrospective study was conducted in2012. The eligible participants were all the adults registered in Nanjing Red Cross Eye Bank to donate their corneas after death during the period of 2001 and *** logistic regression models were applied to investigate the influence factors for successful donation,the outcome events. RESULTS: Totally, 210 of 328(64.0%) registered potential donors successfully donated their corneas after death. The mean(SD) age at registration was 64.7(12.5)for all participants, with 65.5(10.1) and 63.2(15.8) for successful and unsuccessful donors, respectively. With multivariate logistic regression analysis, five factors, the willingness of donation, age, education level, residence area, and cause of death were identified to be associated with successful corneal ***: The willingness of donation and some socio-demographic factors might substantially affect their successful donation after death for people who registered to donate corneas.

关键词： cornea donation influence factors China

Distributed Economic MPC for Synergetic Regulation of the Voltage of an Island DC Micro-Grid

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IEEE/CAA Journal of Automatica Sinica 2024年第3期11卷 734-745页

作者： Yi Zheng Yanye Wang xun Meng Shaoyuan li Hao chen IEEE the Department of Automation Shanghai Jiao Tong UniversityShanghai 200240 the Key Laboratory of System Control and Information Processing Ministry of Education of ChinaShanghai 200240China Haixi Institutes Chinese Academy of SciencesJinjiang 362216China

In this paper,distributed model predictive control(DMPC) for island DC micro-grids(MG) with wind/photovoltaic(PV)/battery power is proposed,which coordinates all distributed generations(DG) to stabilize the bus voltage together with the insurance of having computational efficiency under a real-time *** on the feedback of the bus voltage,the deviation of the current is dispatched to each DG according to cost over the prediction ***,to avoid the excessive fluctuation of the battery power,both the discharge-charge switching times and costs are considered in the model predictive control(MPC) optimization problems.A Lyapunov constraint with a time-varying steady-state is designed in each local MPC to guarantee the stabilization of the entire *** voltage stabilization of the MG is achieved by this strategy with the cooperation of *** numeric results of applying the proposed method to a MG of the Shanghai Power Supply Company shows the effectiveness of the distributed economic MPC.

关键词： Distributed model predictive control(DMPC) Lyapunovbased model predictive control micro-grid(MG) voltage control

Cardiogenic shock and asphyxial cardiac arrest due to glutaric aciduria typeⅡ

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World Journal of Emergency Medicine 2023年第1期14卷 72-74页

作者： Hai-ping Xie Wei-jia Zeng li-xun chen Zhang-xin Xie Xiao-ping Wang Shen Zhao Shengli Clinical Medical College of Fujian Medical University Fuzhou 350001China Department of Emergency Fujian Provincial HospitalFuzhou 350001China Fujian Provincial Key Laboratory of Emergency Medicine Fuzhou 350001China Department of Critical Care Medicine Beijing Friendship HospitalCapital Medical UniversityBeijing 100050China

lipid storage myopathy(LSM)is a manifestation of lipid dysmetabolism,presenting with lipid accumulation in *** mechanism includes defects in intracellular triglyceride catabolism,transport of long-chain fatty acids and carnitine,or fatty acidβ-oxidation.[1]Among LSMs,the most common type is multiple acyl-coenzyme A dehydrogenase deficiency(MADD).

关键词： oxidation shock

Real-time identification of multiple nanoclusters with a protein nanopore in single-cluster level

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Nano Research 2024年第1期17卷 262-269页

作者： ling Zhang Peilei He Huang chen Qingda liu libo li xun Wang Jinghong li Department of Chemistry Center for BioAnalytical ChemistryKey Laboratory of Bioorganic Phosphorus Chemistry&Chemical BiologyTsinghua UniversityBeijing 100084China School of Chemistry and Chemical Engineering Guangdong Prov Key Lab Green Chem Prod TechnolSouth China University of TechnologyGuangzhou 510640China New Cornerstone Science Laboratory Shenzhen 518054China Beijing Institute of life Science and Technology Beijing 102206China Center for BioAnalytical Chemistry Hefei National Laboratory of Physical Science at MicroscaleUniversity of Science and Technology of ChinaHefei 230026China

It is important and challenging to analyze nanocluster structure with atomic ***,α-hemolysin nanopore was used to identify nanoclusters at the single molecule level by providing two-dimensional(2D)dwell time–current blockage spectra and translocation event frequency which sensitively depended on their *** such as Anderson,Keggin,Dawson,and a few lacunary Dawson polyoxometalates with very similar structures,even with only a two-atom difference,could be *** nanopore device could simultaneously measure multiple nanoclusters in a mixture qualitatively and ***,molecular dynamics(MD)simulations provided microscopic understandings of the nanocluster translocation dynamics and yielded 2D dwell time–current blockage spectra in close agreement with *** nanopore platform provides a novel powerful tool for nanocluster characterization.

关键词： nanopore single-molecule nanocluster polyoxometalates real-time detection

Detection of Oscillations in Process Control Loops From Visual Image Space Using Deep Convolutional Networks

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IEEE/CAA Journal of Automatica Sinica 2024年第4期11卷 982-995页

作者： Tao Wang Qiming chen xun Lang Lei Xie Peng li Hongye Su the Department of Electronic Engineering the School of InformationYunnan UniversityKunming 650091China DAMO Academy Alibaba GroupHangzhou 311100China the State Key Laboratory of Industrial Control Technology Institute of Cyber-Systems and ControlZhejiang UniversityHangzhou 310027China

Oscillation detection has been a hot research topic in industries due to the high incidence of oscillation loops and their negative impact on plant *** numerous automatic detection techniques have been proposed,most of them can only address part of the practical *** oscillation is heuristically defined as a visually apparent periodic ***,manual visual inspection is labor-intensive and prone to missed *** neural networks(CNNs),inspired by animal visual systems,have been raised with powerful feature extraction *** this work,an exploration of the typical CNN models for visual oscillation detection is ***,we tested MobileNet-V1,ShuffleNet-V2,Efficient Net-B0,and GhostNet models,and found that such a visual framework is well-suited for oscillation *** feasibility and validity of this framework are verified utilizing extensive numerical and industrial *** with state-of-theart oscillation detectors,the suggested framework is more straightforward and more robust to noise and *** addition,this framework generalizes well and is capable of handling features that are not present in the training data,such as multiple oscillations and outliers.

关键词： Convolutional neural networks(CNNs) deep learning image processing oscillation detection process industries

Increase of chiral sensing ability in host-guest chemistry by magnetic anisotropy

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Science China Chemistry 2024年第8期67卷 2775-2782页

作者： Jia-liang chen Bin li Feng Yang Tiesheng Shi xun-cheng Su State Key Laboratory of Elemento-organic Chemistry Tianjin Key Laboratory of Biosensing and Molecular RecognitionCollege of ChemistryNankai UniversityTianjin 300071China College of Chemistry Chemical Engineering and Materials ScienceZaozhuang UniversityZaozhuang 277160China

Enantiomeric molecules generally play distinct functions in chemistry,biology,and *** physical and chemical properties of chiral analytes lay difficulty in discrimination and quantification of the *** report herein an efficient approach of increasing the chiral sensing ability ofβ-cyclodextrin(β-CD),a widely used host molecule,in the hostguest chemistry by magnetic anisotropy.A rigid and chiral lanthanide binding tag was attached to theβ-CD to amplify the changes of nuclear magnetic resonance(NMR)signals in the host-guest recognition *** installation of the paramagnetic lanthanide ion inβ-CD greatly enhances the enantiomeric discrimination up to 30-fold in comparison with the diamagneticβ-CD *** addition,the magnitude of the paramagnetic effects is tunable according to the diverse range of paramagnetic strength of the lanthanide *** reported method significantly increases the chiral sensing ability ofβ-CD,which can be applied to other host *** transferred paramagnetic effects,pseudocontact shifts(PCSs)and paramagnetic relaxation enhancements(PREs),from the host to the guest molecules,are valuable structural restraints to determine the absolute stereochemistry of the chiral *** strategy does not need modification of the analytes and is complementary to the reported analytical methods that rely on the functionalization of the chiral analytes.

关键词： chiral recognition nuclear magnetic resonance host-guest chemistry magnetic anisotropy lanthanide ions

Machine learning for prediction of retained austenite fraction and optimization of processing in quenched and partitioned steels

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Journal of Iron and Steel Research International 2024年第8期31卷 2002-2013页

作者： Shuai Wang Jie li li-yang Zeng xun-wei Zuo Nai-lu chen Yong-hua Rongg Shanghai Key Laboratory of Materials Laser Processing and Modification School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China

The metastable retained austenite(RA)plays a significant role in the excellent mechanical performance of quenching and partitioning(Q&P)steels,while the volume fraction of RA(V_(RA))is challengeable to directly predict due to the complicated relationships between the chemical composition and process(like quenching temperature(Qr)).A Gaussian process regression model in machine learning was developed to predict V_(RA),and the model accuracy was further improved by introducing a metallurgical parameter of martensite fraction(fo)to accurately predict V_(RA) in Q&P *** developed machine learning model combined with Bayesian global optimization can serve as another selection strategy for the quenching temperature,and this strategy is very effcient as it found the"optimum"Qr with the maximum V_(RA) using only seven consecutive *** benchmark experiment also reveals that the developed machine learning model predicts V_(RA) more accurately than the popular constrained carbon equilibrium thermodynamic model,even better than a thermo-kinetic quenching-partitioning-tempering-local equilibrium model.

关键词： Q&P steel Retained austenite fraction Machine learning Quenching temperature Gaussian process regression model

On the Innovation,Design,Construction,and Experiments of OMEGA-Based SSPS Prototype:The Sun-Chasing Project

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Engineering 2024年第5期36卷 90-101页

作者： Baoyan Duan Yiqun Zhang Guangda chen Ze Zhao Jianwei Mi xun li lin Yang Xi li Research Institute on Mechatronics Xidian UniversityXi’an 710071China Research Institute of Antenna Xidian UniversityXi’an 710071China

This study systematically introduces the development of the world’s first full-link and full-system ground demonstration and verification system for the OMEGA space solar power satellite(SSPS).First,the OMEGA 2.0 innovation design was ***,field-coupling theoretical models of sunlight concentration,photoelectric conversion,and transmitting antennas were established,and a systematic optimization design method was ***,a beam waveform optimization methodology considering both a high beam collection efficiency and a circular stepped beam shape was ***,a control strategy was developed to control the condenser pointing toward the sun while maintaining the transmitting antenna toward the ***,a high-efficiency heat radiator design method based on bionics and topology optimization was ***,a method for improving the rectenna array’s reception,rectification,and direct current(DC)power synthesis efficiencies is ***,high-precision measurement technology for high-accuracy beam-pointing control was ***,a smart mechanical structure was designed and ***,the developed SSPS ground demonstration and verification system has the capacity for sun tracking,a high concentration ratio,photoelectric conversion,microwave conversion and emission,microwave reception,and rectification,and thus satisfactory results were obtained.

关键词： OMEGA-SSPS Full-link and full-system Beam collection efficiency Circular stepped beam shape Smart structure Field coupling theoretical model `Beam pointing control