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FTA与RBF方法结合的某型飞机起落架故障诊断

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液压气动与密封 2024年第5期44卷 20-23页

作者：李锋冯珂李晨旭赵德中陈振西安航空学院飞行器学院陕西西安710089

为了提高某型飞机起落架故障诊断率,分别采用故障树分析法(Fault Tree Analysis,FTA)和FTA与RBF神经网络(Radial Basis Function,RBF)的方法对起落架常见故障进行诊断。首先根据起落架工作原理图,采用FTA方法建立故障树及故障结构函数,... 详细信息

为了提高某型飞机起落架故障诊断率,分别采用故障树分析法(Fault Tree Analysis,FTA)和FTA与RBF神经网络(Radial Basis Function,RBF)的方法对起落架常见故障进行诊断。首先根据起落架工作原理图,采用FTA方法建立故障树及故障结构函数,得到所有的最小割集,计算故障失效概率;然后按照最小割集重要度,筛选出RBF神经网络训练样本的变量数目;最后再结合国内某维修单位的故障统计数据,运用RBF神经网络建立了故障诊断模型,并对模型进行了训练和测试。结果表明,FTA定量计算得到的故障失效概率为71.60%,FTA+RBF结合方法的故障诊断平均预测误差为1.0%。

关键词：起落架 FTA RBF神经网络故障诊断

A modern survey method for determining live loads based on multi-source and open-access data on the Internet

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Frontiers of Structural and Civil Engineering 2024年第8期18卷 1135-1147页

作者： Chi xu Jun chen Jie li School of Civil Engineering Tongji UniversityShanghai 200092China The State Key Laboratory on Disaster Reduction in Civil Engineering Tongji UniversityShanghai 200092China

Sufficient survey data are required to describe the stochastic behaviors of live ***,due to manual and on-site operation required by traditional survey methods,traditional surveys face challenges like occupant resistance,high costs,and long implementation *** study proposes a new survey method to access live load data online and *** samples are acquired from multi-source,open-access and dynamically updated data on the *** change intervals,geometrical dimensions and object quantities are obtained from transaction information,building attributes and virtual reality models on real estate websites,*** object weights are collected from commodity information on e-commerce *** integration of the aforementioned data allows for the extraction of necessary statistics to describe a live load *** proposed method is applied to a live load survey in China,covering 20040 m^(2),with around 90000 samples acquired for object weights and load *** survey results reveal that about 70%−80%of the amplitude statistics are attributable to 1/6 of the total object types.

关键词： live load online survey method data acquisition data integration

Risk factors, clinical features, and short-term prognosis of spontaneous fungal peritonitis in cirrhosis: A matched case-control study

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World Journal of Clinical Cases 2019年第17期7卷 2438-2449页

作者： Chun-Hong Huang Lan-Tian Pang li-chen xu Tian-Tian Ge Qiao-Mai xu Zhi chen State Key Laboratory for Diagnosis and Treatment of Infectious Diseases Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases The First Affiliated HospitalZhejiang University School of Medicine

BACKGROUND Spontaneous peritonitis is one of the most common infectious complications in cirrhotic patients with *** fungal peritonitis (SFP) is a type of spontaneous peritonitis that is a less recognized but devastating complication in end-stage *** high mortality was previously noted,scant data are available to fully define the factors responsible for the occurrence of SFP and its *** To illustrate the differences between SFP and spontaneous bacterial peritonitis (SBP) and discuss the risk factors for the occurrence of SFP and its short-term *** We performed a matched case-control study between January 1,2007 and December 30,*** with SFP were included in a case ***-,age-,and time-matched patients with SBP were included in a control group and were further divided into control-1 group (positive bacterial culture) and control-2 group (negative bacterial culture).The clinical features and laboratory parameters,severity models,and prognosis were compared between the case and control *** regression analysis was used to determine the risk factors for occurrence,and the Cox regression model was used to identify the predictive factors for short-term mortality of *** Patients with SFP exhibited more severe systemic inflammation,higher ascites albumin and polymorphonuclear neutrophils,and a worsened 15-d mortality than patients in the control *** administration (case vs control-1: OR = 1.063,95%CI: 1.012-1.115,P = 0.014;case vs control-2: OR = 1.054,95%CI: 1.014-1.095,P = 0.008) remarkably increased the occurrence of SFP or *** syndrome (HR = 5.328,95%CI: 1.050-18.900) and total bilirubin (μmol/L;HR = 1.005,95%CI: 1.002-1.008) represented independent predictors of SFP-related early *** Long-term antibiotic administration increases the incidence of SFP,and hepatorenal syndrome and total bilirubin are closely related to short-term morta

关键词： Spontaneous fungal peritonitis Risk factor Cirrhosis

Design and simulation investigations on charge transport layers‑free in lead‑free three absorber layer all‑perovskite solar cells

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Frontiers of Optoelectronics 2024年第2期17卷 69-85页

作者： Guangdong li Mingxiang xu Zhong chen School of Physics Southeast UniversityNanjing 211189China

The multiple absorber layer perovskite solar cells(PSCs)with charge transport layers-free(CTLs-free)have drawn widespread research interest due to their simplified architecture and promising photoelectric *** the circumstances,the novel design of CTLs-free inversion PSCs with stable and nontoxic three absorber layers(triple Cs_(3)Bi_(2)I_(9),single MASnI_(3),double Cs_(2)TiBr_(6))as optical-harvester has been numerically simulated by utilizing wxAMPS simulation software and achieved high power conversion efficiency(PCE)of 14.8834%.This is owing to the innovative architecture of PSCs favors efficient transport and extraction of more holes and the slender band gap MASnI_(3)extends the absorption spectrum to the near-infrared periphery compared with the two absorber layers architecture of ***,the performance of the device with p-type-Cs_(3)Bi_(2)I_(9)/p-type-MASnI_(3)/n-type-Cs_(2)TiBr_(6)architecture is superior to the one with the p-type-Cs_(3)Bi_(2)I_(9)/ntype-MASnI_(3)/n-type-Cs_(2)TiBr_(6)architecture due to less carrier recombination and higher carrier life time inside the absorber *** simulation results reveal that Cs_(2)TiF_(6)double perovskite material stands out as the best ***,an excellent PCE of 21.4530%can be obtained with the thicker MASnI_(3)absorber layer thickness(0.4μm).Lastly,the highestperformance photovoltaic devices(28.6193%)can be created with the optimized perovskite doping density of around E15 cm^(3)(Cs_(3)Bi_(2)I_(9)),E18 cm^(3)(MASnI_(3)),and 1.5E19 cm^(3)(Cs_(2)TiBr_(6)).This work manifests that the proposed CTLs-free PSCs with multi-absorber layers shall be a relevant reference for forward applications in electro-optical and optoelectronic devices.

关键词： Multiple absorber layer PSCs CTLS-free·Inverted Narrow-band gap Simulation

The Impact of Aqueous Medium on Gas Yields and Kinetic Behaviors of Hydrogen Isotope Fractionation during Organic Matter Thermal Degradation

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Acta Geologica Sinica(English Edition) 2011年第6期85卷 1466-1477页

作者： LU Shuangfang WANG Min xuE Haitao li Jijun chen Fangwen xu Qingxia Northeast Petroleum University Heilongjiang Province 163318 China

In order to recognize the impact of aqueous medium on gas yields and the kinetic behaviors of hydrogen isotope fractionation during organic matter thermal degradation, the gold tube apparatus was used to conduct thermal simulation experiments by mixing the nC18 with the water of different properties and proportions. The yields of natural gas components, the relation among hydrogen isotope composition of each component and the experimental temperatures vs. heating rates have been obtained, and the results indicate that under the higher temperature conditions, the hydrous experiment has obvious impact on gas yields, such as when more water is added, higher amounts of hydrocarbon gas and H2 are yielded, and the existence of water obviously prolongs the temperature interval with the existence of heavy hydrocarbon gas. It also shows that the hydrogen isotope of hydrocarbon gas generated by the hydrous experiment is obviously lighter than that generated by the anhydrous experiment, and with the increasing amount of added water, the δD value of hydrocarbon gas gradually decreases. Compared with gas yields, the variation of δD value is more sensitive to aqueous medium in the thermal simulation experiment. However, compared with the amount of the added water, the aqueous medium property has smaller impact on the gas yields, which still shows the inherit effect on hydrogen isotope composition of aqueous medium. Through the model simulation and the isotope fractionation behavior analysis, it is validated that the hydrogen isotope fractionation process can be well described by the chemical kinetic model. The difference of reaction fraction of normal methane and D-containing methane is large, corresponding to the same activation energy. The content of normal methane is obviously higher in the part with lower activation energy, while the content of D-containing methane is higher in the part with higher activation energy. Therefore, it will result in larger hydrogen isotope fracti

关键词： hydrogen isotope fractionation chemical kinetics nC18 gas generation hydrous experiment

An interpretable graph convolutional neural network based fault diagnosis method for building energy systems

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Building Simulation 2024年第7期17卷 1113-1136页

作者： Guannan li Zhanpeng Yao liang chen Tao li chengliang xu School of Urban Construction Wuhan University of Science and TechnologyWuhan 430065China Anhui Province Key Laboratory of Intelligent Building and Building Energy-saving Anhui Jianzhu UniversityHefei 230601China State Key Laboratory of Green Building in Western China Xi'an University of Architecture&TechnologyXi'an 710055China Key Laboratory of Low-grade Energy Utilization Technologies and Systems(Chongqing University) Ministry of Education of ChinaChongqing UniversityChongqing 400044China Hubei Provincial Engineering Research Centre of Urban Regeneration Wuhan University of Science and TechnologyWuhan 430081China

Due to the fast-modeling speed and high accuracy,deep learning has attracted great interest in the field of fault diagnosis in building energy systems in recent ***,the black-box nature makes deep learning models generally difficult to *** order to compensate for the poor interpretability of deep learning models,this study proposed a fault diagnosis method based on interpretable graph neural network(GNN)suitable for building energy *** method is developed by following three main steps:(1)selecting NC-GNN as a fault diagnosis model for building energy systems and proposing a graph generation method applicable to the model,(2)developing an interpretation method based on InputXGradient for the NC-GNN,which is capable of outputting the importance of the node features and automatically locating the fault related features,(3)visualizing the results of model interpretation and validating by matching with expert knowledge and maintenance *** was performed using the public ASHRAE RP-1043 chiller fault *** diagnosis results show that the proposed method has a diagnosis accuracy of over 96%.The interpretation results show that the method is capable of explaining the decision-making process of the model by identifying fault-discriminative *** almost all seven faults,their fault-discriminative features were correctly identified.

关键词： fault diagnosis graph neural network building energy system InputXGradient feature interpretation

Aerodynamic Performance of Three Flapping Wings with Unequal Spacing in Tandem Formation

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Journal of Bionic Engineering 2024年第4期21卷 1662-1676页

作者： Min Chang Ziyi xu Zengshuang chen li li xueguang Meng Unmanned System Research Institute National Key Laboratory of Unmanned Aerial Vehicle TechnologyNorthwestern Polytechnical UniversityXi’an710072People’s Republic of China State Key Laboratory for Strength and Vibration of Mechanical Structures School of Aerospace EngineeringXi’an Jiaotong UniversityXi’an710049People’s Republic of China Xi’an Aeronautics Computing Technique Research Institute Aviation Industry Corporation of ChinaXi’an710076People’s Republic of China

To better understand the aerodynamic reasons for highly organized movements of flying organisms,the three-flapping wing system in tandem formation was studied numerically in this *** from previous relevant studies on the multiple flapping wings that are equally spaced,this study emphasizes the impact of unequal spacing between individuals on the aerodynamics of each individual wing as well as the whole *** is found that swapping the distance between the first and second wing with the distance between the second wing and the rearmost wing does not affect the overall aerodynamic performance,but significantly changes the distribution of aerodynamic benefits across each *** the whole flapping cycle,three effects are at *** narrow channel effect and the downwash effect can promote and weaken the wing lift,respectively,while the wake capture effect can boost the *** also shows that these effects could be manipulated by changing the spacing between adjacent *** findings provide a novel way for flow control in tandem formation flight and are also inspiring for designing the formation flight of bionic aircraft.

关键词： Three flapping wings Unequal spacing Aerodynamic performance Tandem formation

Numerical Simulation on the Interaction of an Internal Solitary Wave with a Step-Type Topography

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Journal of Ocean University of China 2008年第2期7卷 119-123页

作者： xu Zhaoting li Qun chen xu YU Jia Physical Oceanography Laboratory and Institute of Physical Oceanography Ocean University of China Qingdao 266100 P R. China

Based on a nonhydrostatic numerical ocean model developed by one of the authors, the interaction of an intemal solitary wave with a step-type topography was investigated. Over the step topography, the flow pattern could be classified into three categories： 1） the propagation and spatial structure of the internal solitary wave was little influenced by the bottom topography, 2） the internal solitary wave was significantly distorted by the blocking effect of the topography without the occurrence of wave breaking and 3） the internal solitary wave was broken as it encountered and passed over the bottom topography. A detailed description of the processes leading to wave breaking is given in this paper together with energy budget analysis. The results revealed that the maximum of the energy dissipation rate is no more than 40%, which is consistent with available experimental data.

关键词： stratified flow intemal solitary wave energy dissipation

Using Improved Particle Swarm Optimization Algorithm for Location Problem of Drone Logistics Hub

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Computers, Materials & Continua 2024年第1期78卷 935-957页

作者： li Zheng Gang xu Wenbin chen School of Mathematics and Computer Sciences Nanchang UniversityNanchang330031China

Drone logistics is a novel method of distribution that will become *** advantageous location of the logistics hub enables quicker customer deliveries and lower fuel consumption,resulting in cost savings for the company’s transportation *** firms must discern the ideal location for establishing a logistics hub,which is challenging due to the simplicity of existing models and the intricate delivery *** simulate the drone logistics environment,this study presents a new mathematical *** model not only retains the aspects of the current models,but also considers the degree of transportation difficulty from the logistics hub to the village,the capacity of drones for transportation,and the distribution of logistics hub ***,this paper proposes an improved particle swarm optimization(PSO)algorithm which is a diversity-based hybrid PSO(DHPSO)algorithm to solve this *** DHPSO,the Gaussian random walk can enhance global search in the model space,while the bubble-net attacking strategy can speed ***,Archimedes spiral strategy is employed to overcome the local optima trap in the model and improve the exploitation of the *** maintains a balance between exploration and exploitation while better defining the distribution of logistics hub locations Numerical experiments show that the newly proposed model always achieves better locations than the current *** DHPSO with other state-of-the-art intelligent algorithms,the efficiency of the scheme can be improved by 42.58%.This means that logistics companies can reduce distribution costs and consumers can enjoy a more enjoyable shopping experience by using DHPSO’s location *** the results show the location of the drone logistics hub is solved by DHPSO effectively.

关键词： Drone logistics location problem mathematical model diversity particle swarm optimization