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Source free unsupervised domain adaptation for electro-mechanical actuator fault diagnosis

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Chinese Journal of Aeronautics 2023年第4期36卷 252-267页

作者： Jianyu WANG Heng ZHANG qiang miao College of Electrical Engineering Sichuan UniversityChengdu 610065China

A common necessity for prior unsupervised domain adaptation methods that can improve the domain adaptation in unlabeled target domain dataset is access to source domain data-set and target domain dataset ***,data privacy makes it not always possible to access source domain dataset and target domain dataset in actual industrial equipment simulta-neously,especially for aviation component like Electro-Mechanical Actuator(EMA)whose dataset are often not shareable due to the data copyright and *** address this problem,this paper proposes a source free unsupervised domain adaptation framework for EMA fault *** proposed framework is a combination of feature network and ***,source domain datasets are only applied to train a source ***,the well-trained source model is trans-ferred to target domain and classifier is frozen based on source domain ***,nearest centroid filtering is introduced to filter the reliable pseudo labels for unlabeled target domain data-set,and finally,supervised learning and pseudo label clustering are applied to fine-tune the trans-ferred *** comparison with several traditional unsupervised domain adaptation methods,case studies based on low-and high-frequency monitoring signals on EMA indicate the effectiveness of the proposed method.

关键词： Data privacy Electro-mechanical actuator Pseudo-label clustering Nearest centroid filtering Unsupervised domain adaptation

An attention graph stacked autoencoder for anomaly detection of electro-mechanical actuator using spatio-temporal multivariate signals

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Chinese Journal of Aeronautics 2024年第9期37卷 506-520页

作者： Jianyu WANG Heng ZHANG qiang miao College of Electrical Engineering Sichuan UniversityChengdu 610065China

Health monitoring of electro-mechanical actuator(EMA)is critical to ensure the security of *** is difficult or even impossible to collect enough labeled failure or degradation data from actual *** autoencoder based on reconstruction loss is a popular model that can carry out anomaly detection with only consideration of normal training data,while it fails to capture spatio-temporal information from multivariate time series signals of multiple monitoring *** mine the spatio-temporal information from multivariate time series signals,this paper proposes an attention graph stacked autoencoder for EMA anomaly ***,attention graph con-volution is introduced into autoencoder to convolve temporal information from neighbor features to current features based on different weight ***,stacked autoencoder is applied to mine spatial information from those new aggregated temporal ***,based on the bench-mark reconstruction loss of normal training data,different health thresholds calculated by several statistic indicators can carry out anomaly detection for new testing *** comparison with tra-ditional stacked autoencoder,the proposed model could obtain higher fault detection rate and lower false alarm rate in EMA anomaly detection experiment.

关键词： Anomaly detection Spatio-temporal informa-tion Multivariate time series signals Attention graph convolution Stacked autoencoder

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枣庄市谷山水库渗漏问题浅析

工程建设与设计 2025年第3期 117-119页

作者：李冬王帅苗强山东省水利勘测设计院有限公司济南250013

枣庄市谷山水库自1966年10月开始蓄水至今已有57年之久,经多次除险加固处理,水库渗漏问题一直未得到解决,严重影响水库效益。论文根据地质测绘、钻探、水文试验、水位观测资料分析水库产生渗漏原因。结果表明,谷山水库库区存在严重垂直... 详细信息

枣庄市谷山水库自1966年10月开始蓄水至今已有57年之久,经多次除险加固处理,水库渗漏问题一直未得到解决,严重影响水库效益。论文根据地质测绘、钻探、水文试验、水位观测资料分析水库产生渗漏原因。结果表明,谷山水库库区存在严重垂直渗漏及邻谷渗漏问题,为水库除漏提供可靠的地质依据。

关键词：坝基库区渗漏量垂直渗漏邻谷渗漏

THE RADIATION AND DIFFRACTION OF WATER WAVES BY A BOTTOM-MOUNTED CIRCULAR CYLINDER IN A TWO-LAYER FLUID

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Journal of Hydrodynamics 2007年第1期19卷 1-8页

作者： YOU Yun-xiang SHI qiang miao Guo-ping School of Naval Architecture Ocean and Civil Engineering Shanghai Jiaotong University Shanghai 200030 China.

An analytical method was proposed to analyze the radiation and diffraction of water waves by a bottom-mounted circular cylinder in a two-layer fluid. Analytical expressions for added mass and damping coefficients, as well as the wave excitation forces of the circular cylinder were obtained by an eigenfunction expansion method. The hydrodynamic forces on the bottom-mounted circular cylinder in a two-layer fluid include not only the added mass and damping coefficients, but also the wave forces of the surface and internal-wave modes. This is different from the case of a homogenous fluid. Some examples were given, showing that density stratification can have a relative large effect on these hydrodynamic forces over a wide range of frequencies.

关键词： two-layer fluid bottom-mounted cylinder,surface-wave mode internal-wave mode hydrodynamic forces

Territorial suitability assessment and function zoning in the Jiuzhaigou earthquake-stricken area

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Journal of Mountain Science 2019年第1期16卷 195-206页

作者： YU Hui qiang miao LIU Shao-quan Institute of Mountain Hazards and Environment Chinese Academy of Sciences University of Chinese Academy of Sciences Chengdu Pidu Disstrict Mianshi Foreign Language School

An earthquake in the Jiuzhaigou area caused numerous secondary disasters, such as rolling stones, land collapse, landslides and debris flow, which badly affected the safety of human settlements and influenced the spatial layout of the post-disaster reconstruction. Therefore, carrying out assessments of land and identifying a suitable zone for human habitats were very important. This research creates the territorial suitability assessment and function zoning conceptual model in the earthquake-stricken area, and the new methods of the territorial suitability evaluation system were used to divide the spatial functional zones of the earthquake stricken area, which provide a theoretical guidance and decisionmaking basis for the reconstruction of the disaster area. The results showed that:(1) The Jiuzhaigou earthquake-stricken area comprises of an ecological area that has a high level of importance to the ecosystem. In the earthquake-stricken area, 65% of national land is at an altitude of 3000-4000 m, and therefore not suitable for a high level of intensive reconstruction, but reconstructed in an eco-friendly manner.(2) The zone suitable for reconstruction comprises mainly of the river valley and the flat terrain of western parts. The land with low suitability is mainly located on steep terrain, such as highmountains and low gullies. The geographic and geomorphic conditions limit the spread of a suitable reconstruction zone.(3) The earthquake-stricken area mainly comprises of a tourism industry gathering area, population gathering area, agriculture and animal husbandry development area, and ecological preservation area with areas of 76 km^2, 44 km^2, 1591 km^2 and 7512 km^2, respectively. Scientifically zoning the reconstruction areas using scientific evaluation may provide guidance for the location of reconstruction sites.

关键词： Jiuzhaigou valley Earthquake-stricken area Territorial suitability Function zoning

Approach to Inversion Design of Dielectric Material Based on the First-Principle

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Chinese Journal of Electronics 2017年第1期26卷 50-57页

作者： miao qiang WU Dewei HE Jing YANG Chunyan XIE Lei Information and Navigation College of Air Force Engineering University Ming De College of Northwestern Polytechnical University

The first-principle is an effective method for the material property calculation. One inversion design idea of dielectric material based on the first-principle was put forward. In this kind of material design thought,the specific demanded dielectric property of material is the starting point of the whole design course. The atomic structure characteristic of the material is solved using the inversion model based on the first-principle. And the key issues needing researching were discussed, these problems were quantized structure of electromagnetic and optic field,the quantized polarization theory of dielectric material, the uniform calculation method of dielectric property and the dielectric material inversion model.

关键词： First-principle Dielectric material Dielectric property Inversion design

High-temperature tribological behaviors of a Cr-Si co-alloyed layer on TA15 alloy

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Chinese Journal of Aeronautics 2017年第2期30卷 846-855页

作者： Lu Haifeng miao qiang Liang Wenping Wang Fang Ding Zheng Xia Jinjiao College of Material Science and Technology Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

A Cr-Si co-alloyed layer was successfully deposited on TA15 alloy by the double glow plasma surface technology to improve its poor wear resistance at elevated *** microstructure,composition,and phase structure of the layer were investigated by SEM,EDS,and *** tribological behaviors of the Cr-Si co-alloyed layer at 20 ℃ and 500 ℃ were analyzed in *** results indicated that the friction coefficient and wear rate of the Cr-Si coalloyed layer at 20 ℃ and 500 ℃ were much lower than those of the substrate,which was due to higher hardness and superior elastic *** layer may become an approach to effectively improving the wear resistance of TA15 alloy at elevated temperature.

关键词： Cr-Si layer High temperature TA 15 alloy Tribological behavior Wear mechanism

Enantioselective epoxidation of nonfunctionalized alkenes catalyzed by recyclable new homochiral bis-diamine-bridged bi-Mn(salen) complexes

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Science China Chemistry 2013年第5期56卷 604-611页

作者： HUANG XueMei FU XiangKai JIA ZiYong miao qiang WANG GuoMing College of Chemistry and Chemical Engineering Research Institute of Applied Chemistry Southwest University The Key Laboratory of Applied Chemistry of Chongqing Municipality The Key Laboratory of Eco-environments in Three Gorges Reservoir Region Ministry of Education

Three new homochiral bis-diamine-bridged bi-Mn（salen） complexes were synthesized. Their catalysis on asymmetric epoxidation of a-methylstyrene, styrene and indene was studied with NaC10 and m-CPBA as oxidants respectively. This homogeneous catalyst exhibited comparable catalytic activity and enantioselectivity to the Jacobsen＇s catalyst in the asymmetric epoxidation of unfunctionalized olefins. Furthermore, the catalyst could be conveniently recovered and reused at least five times without significant losses of both activity and enantioselectivity. Specially, it also could be efficiently used in large-scale reactions with superior catalytic disposition being maintained at the same level, which provided the potential for the applications in industry. The effect of axial bases, temperature and solvent on activity and enantioselectivity of the catalytic system were also studied.

关键词： homochiral bi-Mn(salen) complex enantioselective asymmetric epoxidation unfunctionalized olefins

On Convergence of MRQI and IMRQI Methods for Hermitian Eigenvalue Problems

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Communications on Applied Mathematics and Computation 2021年第1期3卷 189-197页

作者： Fang Chen Cun-qiang miao Galina V.Muratova School of Applied Science Beijing Information Science and Technology UniversityBeijing 100192China School of Mathematics and Statistics Central South UniversityChangsha 410083China Laboratory of Computational Mechanics I.I.Vorovich Institute of MathematicsMechanics and Computer ScienceSouthern Federal UniversityRostov-on-Don 344090Russia

Bai et *** the multistep Rayleigh quotient iteration(MRQI)as well as its inexact variant(IMRQI)in a recent work(***.77:2396–2406,2019).These methods can be used to effectively compute an eigenpair of a Hermitian *** convergence theorems of these methods were established under two conditions imposed on the initial guesses for the target eigenvalue and *** this paper,we show that these two conditions can be merged into a relaxed one,so the convergence conditions in these theorems can be weakened,and the resulting convergence theorems are applicable to a broad class of *** addition,we give detailed discussions about the new convergence condition and the corresponding estimates of the convergence errors,leading to rigorous convergence theories for both the MRQI and the IMRQI.

关键词： Hermitian eigenvalue problem MRQI IMRQI Convergence