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Research Review of Principles and Methods for Ultrasonic Measurement of Axial Stress in Bolts

Chinese Journal of Mechanical Engineering 2020年第1期33卷 44-59页

作者： Qinxue pan Ruipeng pan Chang shao Meile Chang xiaoyu Xu School of Mechanical Engineering Beijing Institute of TechnologyBeijing 100081China Key Laboratory of Fundamental Science for Advanced Machining Beijing Institute of TechnologyBeijing 100081China

Bolts are important fasteners indispensable in the manufacturing field for their advantages, which include convenient assembly and disassembly, easy maintenance, refastenability to prevent looseness, and the avoidance of a phase change in the connected material composition. The precise control of the tightening force in bolts is closely related to the safety and reliability of the connected equipment or structure. Although there are many methods for estimating the tightening force applied to a bolt during assembly, poor accuracy in controlling the preload during the tightening process and a lack of monitoring to determine the residual axial force in service remain issues in evaluating the safety of bolted assemblies. As a nondestructive testing technology, ultrasonic measurement can be applied to successfully address these issues. In order to help researchers understand the theoretical basis and technological development in this field and to equip them to conduct further in-depth research, in this review, the basic knowledge describing the state of stress and deformation of bolts, as well as conventional testing methods are summarized and analyzed. Then, through a review of recent research of the ultrasonic measurement of the axial stress in bolts, the influence of the e ective stressed length and temperature are analyzed and proposed methods of calibration and compensation are reviewed. In order to avoid coupling errors caused by traditional piezoelectric transducers, two newly proposed ultrasonic coupling technologies, the electromagnetic acoustic transducer(EMAT) and the permanent mounted transducer system(PMTS), are reviewed. Finally, the new direction of research of the detection of residual axial stress in in-service bolts that have been assembled to yield is discussed.

关键词： Bolted connections Axial stress Ultrasonic waves Influencing factors Coupling techniques

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优化HS-SPME-GC-MS方法表征香菇不同成熟阶段的关键挥发性化合物

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食品科学 2025年第1期46卷 74-82页

作者：侯振山许贺然夏榕嵘李昀婷王娅飞潘松辛广沈阳农业大学食品学院辽宁沈阳110866

通过优化的顶空固相微萃取结合气相色谱-质谱联用技术鉴定香菇不同成熟阶段挥发性化合物,并采用气味活性值(odor activity value,OAV)和偏最小二乘判别分析(partial least squares discriminant analysis,PLS-DA)进行分析。结果表明:最... 详细信息

通过优化的顶空固相微萃取结合气相色谱-质谱联用技术鉴定香菇不同成熟阶段挥发性化合物,并采用气味活性值(odor activity value,OAV)和偏最小二乘判别分析(partial least squares discriminant analysis,PLS-DA)进行分析。结果表明:最佳提取条件为1.0 g香菇样品在50℃提取25 min,解吸3 min;在香菇不同成熟阶段共鉴定出71种挥发性化合物,不同成熟阶段挥发性化合物种类和含量存在显著差异(P1和OAV≥1,是香菇不同成熟阶段最重要的差异挥发性化合物。本研究为探究香菇成熟过程中香气形成机制提供一定理论依据。

关键词：香菇成熟阶段香气挥发性化合物顶空固相微萃取气相色谱-质谱偏最小二乘判别分析

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General variational solution for seismic and static active earth pressure on rigid walls considering soil tensile strength cut-off

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2023年第5期24卷 432-449页

作者： Shiguo xiaO Yuan QI pan xia Key Laboratory of High-Speed Railway Engineering Ministry of EducationSouthwest Jiaotong UniversityChengdu 60031China School of Civil Engineering Southwest Jiaotong UniversityChengdu 610031China Department of Geological Engineering Southwest Jiaotong UniversityChengdu 610031China

According to the limit equilibrium state of soils behind rigid walls and the pseudo-static approach,a general closed-form solution to seismic and static active earth pressure on the walls,which considers shear and tension failure of the retained soil,is put forward using a variational calculus *** application point of the active resultant force specified in the proposed method is explained with a clear physical meaning related to possible movement modes of the *** respect of the derived nine dependent equations reflecting the functional characteristics of the earth pressure,the proposed method can be performed easily via an implicit *** are 13 basic factors related to the retained soils,walls,and external loads to be involved in the proposed *** tension crack segment of the slip surface is obviously influenced by these parameters,apart from vertical seismic coefficient and geometric bounds of the surcharge,but the shear slip segment maintains an approximately planar shape almost uninfluenced by these ***,the proposed method quantitatively reflects that the resultant of the active earth pressure is always within a limited range under different possible movements of the same wall.

关键词： Active earth pressure Tensile strength cut-off Variational calculus method Pseudo-static method Strip surcharge

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Emerging roles of podoplanin in vascular development and homeostasis

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Frontiers of Medicine 2015年第4期9卷 421-430页

作者： Yanfang pan Lijun xia Department of Non-Communicable Diseases Control and Prevention Zhejiang Provincial Center for Disease Control and Prevention Hangzhou 310051 China State Key Laboratory of Bio-organic and Natural Products Chemistry Shanghai Institute of Organic Chemistry Chinese Academy of Sciences Shanghai 200032 China Cardiovascular Biology Research Program Oklahoma Medical Research Foundation OK 73104 USA

Podoplanin （PDPN） is a mucin-type O-glycoprotein expressed in diverse cell types, such as lymphatic endothelial cells （LECs） in the vascular system and fibroblastic reticular cells （FRCs） in lymph nodes. PDPN on LECs or FRCs activates CLEC-2 in platelets, triggering platelet activation and/or aggregation through downstream signaling events, including activation of Syk kinase. This mechanism is required to initiate and maintain separation of blood and lymphatic vessels and to stabilize high endothelial venule integrity within lymph nodes. In the vascular system, normal expression of PDPN at the LEC surface requires transcriptional activation of Pdpn by Proxl and modification of PDPN with core 1-derived O-glycans. This review provides a comprehensive overview of the roles of PDPN in vascular development and lymphoid organ maintenance and discusses the mechanisms that regulate PDPN expression related to its function.

关键词： podoplanin CLEC-2 Proxl O-glycosylation lymphatic vascular development and maintenance lymphoid organ homeostasis

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A novel technique for measuring 3D deformation of adhesively bonded single lap joint

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Science China(Physics,Mechanics & Astronomy) 2016年第1期59卷 58-65页

作者： Bing pan LuJun Ma Yong xia Institute of Solid Mechanics Beihang University State Key Lab of Automotive Safety and Energy Tsinghua University

An easy-to-implement yet practical single-camera microscopic stereo-digital image correlation(stereo-DIC) technique is proposed for surface three-dimensional(3D) deformation measurement of singe lap joint(SLJ) samples subjected to mechanical loads. The basic principles, optical configurations and implementation procedures of the proposed technique are described in detail. Compared with existing single-camera 2D-DIC technique, which has been regularly used for in-plane deformation measurement of a SLJ specimen, the proposed technique offers the special merit of simultaneously determining all the three displacement components by simply adding two additional optical elements to existing single-camera 2D-DIC systems. The accuracy and effectiveness of the proposed technique is demonstrated by measuring the 3D deformation of a SLJ specimen subjected to quasi-static tensile loads.

关键词： digital image correlation single lap joint deformation measurement

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A COUPLED DYNAMIC MODEL OF BRAND ACCEPTANCE AND PROMOTIVE INFORMATION SPREADING

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Journal of Systems Science and Systems Engineering 2018年第5期27卷 677-689页

作者： Qian pan Haoxiang xia Shuangling Luo Institute of Systems Engineering Dalian University of Technology 116024 China College of Shipping Economics andManagement & Collaborative Innovation Center for Transport Studies

When people try to decide to buy or not to, they are often influenced by both their inherentopinions and the social marketing activities e.g. advertising, social news with strong point of *** people will make their final choice, or even convince other people to buy. After all, this is thebrand acceptance formation process. Factually, the dynamics of brand acceptance is essentially aninterwoven dynamics of endogenous opinion dynamics disturbed by an information diffusion *** have a better understanding of the dynamics of brand acceptance, we propose and analyze a coupledagent-based dynamic model that combines the Majority-Rule-based Voter model in opinion dynamicswith the SI Model for information spreading to analyze the dynamics of brand acceptance in socialmedia. We focus on two important parameters in diffusion dynamics： the decayed transmission rate （fl）and the diffusion frequency （f）. When the system is stable, the order parameter of the system is theduration time （r）. In the absence of opinion interaction, the simulation results indicate that, when abrand tries to occupy a larger market share through social marketing approaches, it is always effectiveto let the opponent to be the propaganda target. While with the Majority-Rule-based Voter Modelincluded, we observe that the opinion interaction could have a dual function, which shows that a brandholding a small market share in the first place needs to adopt diverse marketing approaches accordingto different marketing environment types.

关键词： Coupled dynamics social marketing dynamics of brand acceptance opinion dynamics diffusion dynamics

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Efficient hybrid neural network for spike sorting

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Journal of Systems Engineering and Electronics 2013年第1期24卷 157-164页

作者： Hongge Li pan Yu Tongsheng xia School of Electronics Information Engineering Beihang University

Artificial neural network has been used successfully to develope the automatic spike extraction. In order to address some of the problems before the wireless transmission of the implantable chip, the automatic spike sorting method with low complexity and high efficiency is proposed based on the hybrid neural network with the principal component analysis network （PCAN） and normal boundary response （NBR） self-organizing mapping （SOM） net- work classifier. An automatic PCAN technique is used to reduce the dimension and eliminate the correlation of the spike signal. The NBR-SOM network performs the spike sorting challenge and improves the classification performance. The experimental results show that based on the hybrid neural network, the spike sorting method achieves the accuracy above 97.91% with signals contain- ing five classes. The proposed NBR-SOM network classifier is to further improve the stability and effectiveness of the classification system.

关键词： neural network spike sorting implantable microsys-tern.

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Trifocal Tensor Based Feature Matching Algorithm

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Journal of Beijing Institute of Technology 2020年第4期29卷 484-488页

作者： Mingwei shao pan Wang School of Information and Control Engineering Qingdao University of TechnologyQingdao 266000ShandongChina

Feature matching is of significance in the field of computer *** this paper,a trifocal tensor based feature matching algorithm is proposed for three views,including a trinocular vision *** matching point-pairs can be determined according to generic matching algorithms,on which an initial trifocal tensor of three views can be *** the initial matching point-pairs should be ***,the trifocal tensor will be ***,the optimized trifocal tensor can be *** fundamental matrix of every two views can be ***,in the trinocular vision sensor,the trifocal tensor can be calculated based on the intrinsic parameter matrix of each *** the strict constraint provided by the trifocal tensor,feature matching results will be *** show that our proposed algorithm has the characteristics of feasibility and precision.

关键词： optics trifocal tensor feature matching

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Preserving details in semantics-aware context for scene parsing

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Science China(Information Sciences) 2020年第2期63卷 79-92页

作者： Shuai MA Yanwei panG Jing pan Ling shao Tianjin Key Laboratory of Brain-Inspired Intelligence Technology School of Electrical and Information EngineeringTianjin University School of Electronic Engineering Tianjin University of Technology and Education

Great success of scene parsing(also known as, semantic segmentation) has been achieved with the pipeline of fully convolutional networks(FCNs). Nevertheless, there are a lot of segmentation failures caused by large similarities between local appearances. To alleviate the problem, most of existing methods attempt to improve the global view of FCNs by introducing different contextual modules. Though the reconstructed high resolution output of these methods is of rich semantics, it cannot faithfully recover the fine image details owing to lack of desired precise low-level information. To overcome the problem, we propose to improve the spatial decoding process through embedding possibly lost low-level information in a principled way. To this end, we make the following three contributions. First, we propose a semantics conformity module to make low-level features variations agnostic. Second, we introduce semantics into the conformed low level features through guidance from semantically aware features. Finally, we institute the availability of various possible contextual features at feature fusion to enrich context information. The proposed approach demonstrates competitive performance on challenging PASCAL VOC 2012, Cityscapes,and ADE20K benchmarks in comparison to the state-of-the-art methods.

关键词： fully convolutional networks semantic segmentation cityscapes semantic-aware context

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Elliptical encirclement control capable of reinforcing performances for UAVs around a dynamic target

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Defence Technology（防务技术） 2024年第2期32卷 104-119页

作者： Fei Zhang Xingling shao Yi xia Wendong Zhang National Key Laboratory for Electronic Measurement Technology School of Instrument and ElectronicsNorth University of ChinaTaiyuan030051China

Most researches associated with target encircling control are focused on moving along a circular orbit under an ideal environment free from external ***,elliptical encirclement with a time-varying observation radius,may permit a more flexible and high-efficacy enclosing solution,whilst the non-orthogonal property between axial and tangential speed components,non-ignorable environmental perturbations,and strict assignment requirements empower elliptical encircling control to be more challenging,and the relevant investigations are still *** this line,an appointed-time elliptical encircling control rule capable of reinforcing circumnavigation performances is developed to enable Unmanned Aerial Vehicles(UAVs)to move along a specified elliptical path within a predetermined reaching *** remarkable merits of the designed strategy are that the relative distance controlling error can be guaranteed to evolve within specified regions with a designer-specified convergence ***,wind perturbations can be online counteracted based on an unknown system dynamics estimator(USDE)with only one regulating parameter and high computational *** tool demonstrates that all involved error variables are ultimately limited,and simulations are implemented to confirm the usability of the suggested control algorithm.

关键词： Elliptical encirclement Reinforced performances Wind perturbations UAVs

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