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Reliability-based selective maintenance for redundant systems with dependent performance characteristics of components

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Journal of Systems Engineering and Electronics 2023年第3期34卷 804-814页

作者： CAO Hui duan Fuhai duan yu’nan School of Mechanical Engineering Dalian University of TechnologyDalian 116024China

The reliability-based selective maintenance(RSM)decision problem of systems with components that have multiple dependent performance characteristics(PCs)reflecting degradation states is addressed in this paper.A vine-Copulabased reliability evaluation method is proposed to estimate the reliability of system components with multiple ***,the marginal degradation reliability of each PC is built by using the Wiener stochastic process based on the PC’s degradation *** joint degradation reliability of the component with multiple PCs is established by connecting the marginal reliability of PCs using *** addition,two RSM decision models are developed to ensure the system accomplishes the next *** genetic algorithm(GA)is used to solve the constraint optimization problem of the models.A numerical example illustrates the application of the proposed RSM method.

关键词： D-vine genetic algorithm(GA) reliability-based selective maintenance(RSM) redundant system Wiener stochastic process

定向电场下W_(6)C_(6)团簇的超卤素调制及非线性光学特性

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原子与分子物理学报 2025年第3期42卷 72-76页

作者：蔡璧钧段宇静魏强重庆理工大学理学院重庆400050

本文采用密度泛函(DFT)方法研究了定向外电场(OEEF)对W_(6)C_(6)团簇几何结构、电子性质以及非线性光学响应(NLO)的影响.计算结果表明W_(6)C_(6)的结构在一定OEEF强度下可以保持稳定.OEEF可以增大W_(6)C_(6)团簇的电子亲和能(EA值),且... 详细信息

本文采用密度泛函(DFT)方法研究了定向外电场(OEEF)对W_(6)C_(6)团簇几何结构、电子性质以及非线性光学响应(NLO)的影响.计算结果表明W_(6)C_(6)的结构在一定OEEF强度下可以保持稳定.OEEF可以增大W_(6)C_(6)团簇的电子亲和能(EA值),且在特定强度下,OEEF可以将W_(6)C_(6)团簇转变为超卤素.通过对EA值的非线性拟合可以实现对W_(6)C_(6)团簇的连续调制.进一步对不同外电场下W_(6)C_(6)团簇的最高占据分子轨道(HOMO)和最低未占据分子轨道(LUMO)能级进行分析,发现OEEF降低了W_(6)C_(6)团簇LUMO能级是其EA值增大的主因.此外,OEEF可以显著增大W_(6)C_(6)团簇的平均极化率和第一超极化率,尤其是第一超极化率,改变其非线性光学性质.

关键词：定向外电场超原子密度泛函理论 NLO W_(6)C_(6)团簇

Three-dimensional numerical analysis on combustion performance and flow of hybrid rocket motor with multi-segmented grain

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Chinese Journal of Aeronautics 2020年第4期33卷 1181-1191页

作者： Hui TIAN yu duan Hao ZHU School of Astronautics Beihang UniversityBeijing 100083China Key Laboratory of Spacecraft Design Optimization&Dynamic Simulation Technologies Ministry of EducationBeihang UniversityBeijing 100083China

This paper presents the combustion characteristics in hybrid rocket motors with multisegmented grain through three-dimensional numerical ***-segmented grain is composed of several thin grains with two or more *** numerical model consists of Navier-Stokes equations with turbulence,solid fuel pyrolysis,chemical reactions,a fluid–solid coupling model and a regression rate *** simulations adopt 90%Hydrogen Peroxide(HP)and PolyEthylene(PE)as the propellant *** effects of the rotation,port number,fuel grain segment number and mid-chamber length on the flow field and combustion performances are *** results indicate that the multi-segmented grain configuration can strengthen the flow field,and the regression rate and combustion efficiency are *** the cases with two grain segments and three ports for example,the regression rate is increased by 32.4%-45.1%and the combustion efficiency increases by 6%-8.6%in different rotation angles.

关键词： Combustion efficiency Hybrid rocket motor Multi-segmented grain Regression rate Rotation angle

Fault Line Detection Using Waveform Fusion and One-dimensional Convolutional Neural Network in Resonant Grounding Distribution Systems

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CSEE Journal of Power and Energy Systems 2021年第2期7卷 250-260页

作者： Jianhong Gao Moufa Guo duan-yu Chen College of Electrical Engineering and Automation Fuzhou UniversityFuzhou 350108China Department of Electrical Engineering Yuan Ze UniversityTaoyuan 32003TaiwanChina

Effective features are essential for fault *** to the faint characteristics of a single line-to-ground(SLG)fault,fault line detection has become a challenge in resonant grounding distribution *** paper proposes a novel fault line detection method using waveform fusion and one-dimensional convolutional neural networks(1-D CNN).After an SLG fault occurs,the first-half waves of zero-sequence currents are collected and superimposed with each other to achieve waveform *** compelling feature of fused waveforms is extracted by 1-D CNN to determine whether the fused waveform source contains the fault ***,the 1-D CNN output is used to update the value of the counter in order to identify the fault *** the lack of fault data in existing distribution systems,the proposed method only needs a small quantity of data for model training and fault line *** addition,the proposed method owns fault-tolerant *** if a few samples are misjudged,the fault line can still be detected correctly based on the full output results of 1-D *** results verified that the proposed method can work effectively under various fault conditions.

关键词： Fault line detection one-dimensional convolutional neural network resonant grounding distribution systems waveform fusion

OsTHA8 encodes a pentatricopeptide repeat protein required for RNA editing and splicing during rice chloroplast development

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The Crop Journal 2023年第5期11卷 1353-1367页

作者： Yanwei Wang yu duan Pengfei Ai College of Food and Biology Hebei University of Science and TechnologyShijiazhuang 050018HebeiChina

In higher plants, the chloroplast is the most important organelle for photosynthesis and for numerous essential metabolic processes in the cell. Although many genes involved in chloroplast development have been identified, the mechanisms underlying such development are not fully understood. In this study, a rice(Oryza sativa) mutant exhibiting pale green color and seedling lethality was isolated from a mutant library. The mutated gene was identified as an ortholog of THA8(thylakoid assembly 8) in Arabidopsis and maize. This gene is designated as OsTHA8 hereafter. OsTHA8 showed a typical pentatricopeptide repeat(PPR) characteristic of only four PPR motifs. Inactivation of OsTHA8 led to a deficiency in chloroplast development in the rice seedling stage. OsTHA8 was expressed mainly in young leaves and leaf *** OsTHA8 protein was localized to the chloroplast. Loss of function of OsTHA8 weakened the editing efficiency of ndhB-611/737 and rps8-182 transcripts under normal conditions. Y2H and BiFC indicated that OsTHA8 facilitates RNA editing by forming an editosome with multiple organellar RNA editing factor(OsMORF8) and thioredoxin z(OsTRXz), which function in RNA editing in rice chloroplasts. Defective OsTHA8 impaired chloroplast ribosome assembly and resulted in reduced expression of PEP-dependent genes and photosynthesis-related genes. Abnormal splicing of the chloroplast gene ycf3 was detected in ostha8. These findings reveal a synergistic regulatory mechanism of chloroplast biogenesis mediated by RNA, broaden the function of the PPR family, and shed light on the RNA editing complex in rice.

关键词： Oryza sativa L. Chloroplast biogenesis Pentatricopeptide repeat protein RNA editing RNA splicing

Intermittent Arc Fault Detection Based on Machine Learning in Resonant Grounding Distribution Systems

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CSEE Journal of Power and Energy Systems 2023年第2期9卷 599-611页

作者： Ye Tian Mou-Fa Guo duan-yu Chen College of Electrical Engineering and Automation Fuzhou UniversityFuzhou 350108China Department of Electrical Engineering Yuan Ze UniversityTaiwan 32003China Fuzhou Power Supply Company of State Grid Fujian Electric Power Co. Ltd.Fuzhou 350009China

In resonant grounding systems,most single-phaseto-ground faults evolve from IAFs(Intermittent Arc Faults).Earlier detection of IAFs can facilitate fault *** work proposes a novel method based on machine learning for detecting IAFs in three ***,the feature of zero-sequence current is automatically extracted and selected by a newlydesigned FINET(“For IAFs,Neuron Elaboration Net”),instead of traditional feature selection based on time-frequency ***,data of the zero-sequence current divided by different time windows are successively input into the trained FINET.A proposed PSF(principal-subordinate factor)analyses the results obtained from FINET to improve anti-interference in the mentioned IAF detection *** using PSCAD/EMTDC software simulation data show the proposed method is feasible and highly *** addition,the detection result of on-site recorded data demonstrates the effectiveness of the proposed method in practical resonant grounding systems.

关键词： Resonant grounding distribution systems intermittent arc faults(IAFs)detection “For IAFs Neuron Elaboration Net”(FINET) principal-subordinate factor(PSF)

The Silk Textile Embedded in Silk Fibroin Composite: Preparation and Properties

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Chinese Journal of Polymer Science 2018年第9期36卷 1043-1046页

作者： yu duan Xin Chen Zheng-Zhong Shao State Key Laboratory of Molecular Engineering of Polymers Department of Macromolecular Science Laboratory of Advanced Materials Fudan University

Silk reinforced silk-fibroin-based composites were prepared by embedding of silk textile into regenerated silk fibroin （RSF） matrix. The breaking stress and breaking strain of the composites were found 37.7 MPa and 71.1% respectively at （95 ：t： 5）% RH. Morphological analysis was carried out to observe fracture behavior of the samples. The in vitro biodegradation test showed that the composite degraded slowly and lost 70% weight at the end of 168 h. Moreover, compared with RSF pure film, the composite kept strength and toughness much longer time. In conclusion, this composite has the potential for more accurate cytology research and biomedical tests in the future.

关键词： Silk protein Biomaterials Composite Mechanical properties Natural product

Theoretical elastoplastic analysis for foundations with geosynthetic-encased columns

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2012年第7期13卷 506-518页

作者： yuan-yu duan Yi-ping ZHANG Dave CHAN Ya-nan yu College of Civil Engineering and Architecture Zhejiang UniversityHangzhou 310058China Department of Civil and Environmental Engineering University of AlbertaEdmontonAlbertaCanada

As a new technique in ground improvement, geosynthetic-encased columns (GECs) have promising applications in soft soil foundation. By assuming yielding occurs in the columns while the surrounding soil and the geosynthetic remain elastic, an elastoplastic analytical procedure for foundations improved by GECs is proposed. The radial stresses that the geosynthetic provides and the elastoplastic deformations of the foundation resting on a rigid base are derived. A comparison with finite element analysis shows that the proposed method is effective and can provide a reasonable prediction of a GEC's deformation. Subsequent parametric analysis indicates that higher geosynthetic stiffness leads to better performance of the composite foundation. The optimum length of encasement is related to the load acting on the foundation and the permissible vertical and radial displacements of the column. Moreover, as the dilation angle of the column increases, the settlement decreases, especially under high loading. The influence of the encasement is more significant in soils with smaller elastic modulus.

关键词： Geosynthetic-encased columns (GECs) Equal vertical strain Elastoplastic deformation Analytical procedure

Synthesis and Characterization of a Novel Functional Biodegradable Copolymer-Poly(lactic acid-4-hydroxyproline-polyethylene glycol)

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Chinese Chemical Letters 2006年第8期17卷 1125-1128页

作者： Jiu Fang duan yu Bin ZHENG Department of Polymer Science Dalian University of Technology Dalian 116012

A series of poly（lactic acid-4-hydroxyproline-polyethylene glycol）（PLA-Hpr-PEG） copolymers were synthesized by direct melt copolymerization of D,L-lactic acid and 4-hydroxyproline with different feed amount of polyethylene glycol （PEG） 0.1%, 0.5%, 1% and 5%, respectively. The properties of these copolymers were characterized by using IR spectroscopy, proton nuclear magnetic resonance （1H-NMR） spectroscopy, gel permeation chromatography （GPC）, X-ray diffraction and differential scaning calorimetry （DSC）. PLA-Hpr-PEG are amorphous copolymers. Copolymers showed increasing water uptake capacity with increasing PEG percentage in the feed, which result in an increasing degradable rate in phosphate buffer solution （pH 7.4） at 37℃.

关键词： Lactic acid 4-hydroxyproline polyethylene glycol.