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Damage detection in beam-like structures using static shear energy redistribution

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Frontiers of Structural and Civil Engineering 2022年第12期16卷 1552-1564页

作者： xi peng Qiuwei YANG School of Civil and Transportation Engineering Ningbo University of TechnologyNingbo 315211China Engineering Research Center of Industrial Construction in Civil Engineering of Zhejiang Ningbo University of TechnologyNingbo 315211China

In this study,a static shear energy algorithm is presented for the damage assessment of beam-like *** to the energy release principle,the strain energy of a damaged element suddenly changes when structural damage ***,the change in the static shear energy is employed to determine the damage locations in beam-like *** static shear energy is derived from the spectral factorization of the elementary stiffness matrix and structural deflection *** advantage of using shear energy as opposed to total energy is that only a few deflection data points of the beam structure are required during the process of damage *** advantage of the proposed approach is that damage detection can be performed without establishing a structural finiteelement model in *** proposed technique is first validated using a numerical example with single,multiple,and adjacent damage scenarios.A channel steel beam and rectangular concrete beam are employed as experimental cases to further verify the proposed *** results of the simulation and experiment examples indicate that the proposed algorithm provides a simple and effective method for defect localization in beam-like structures.

关键词： damage detection beam structure strain energy static displacement variation energy damage index

Rare nanoparticles shine colors with low-power STED

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Light(Science & Applications) 2022年第7期11卷 1324-1326页

作者： xinzhu Xu peng xi College of Future Technology Peking UniversityBeijingChina

The effect of cascade amplified depletion in lanthanide upconversion systems boosts their own emission bands inhibition,which facilitates multi-color nanoscopy with only one pair of low-power NIR CW lasers.

关键词： Rare lanthanide bands

Parameter estimation of the structured illumination pattern based on principal component analysis (PCA): PCA-SIM

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Light(Science & Applications) 2023年第2期12卷 150-152页

作者： xin Chen Yiwei Hou peng xi Department of Biomedical Engineering College of Future TechnologyPeking University100871 BeijingChina National Biomedical Imaging Center Peking University100871 BejingChina

Principal component analysis(PCA),a common dimensionality reduction method,is introduced into SIM to identify the frequency vectors and pattern phases of the illumination pattern with precise subpixel accuracy,fast sp... 详细信息

关键词： pattern illumination component

Raster-scanning Donut simplifies MINFLUX and provides alternative implement on other scanning-based microscopes

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Light(Science & Applications) 2022年第10期11卷 2271-2275页

作者： xinzhu Xu Shu Jia peng xi Department of Biomedical Engineering College of Future TechnologyPeking UniversityBeijing 100871China Wallace H.Coulter Department of Biomedical Engineering Georgia Institute of Technology and Emory UniversityAtlantaGeorgia 30332USA UTS-SUStech Joint Research Centre for Bio-medical Materials&Devices Department of Biomedical EngineeringCollege of EngineeringSouthern University of Science and TechnologyShenzhenGuangdong 518055China National Biomedical Imaging Center Peking UniversityBeijing 100871China

A donut excitation moves around a single molecule with a zigzag configuration lattice by *** a method implemented in scanning fluorescence microscopy simplifies the conventional MINFLUX *** of hollow zero-intensity excitation,single-pixel detection,time-correlated single photon counting,and drift stabilization,the system achieves localization precision and resolution very close to conventional MINFLUX theoretically and *** averaged high-SNR reference,and pixel-registered intensity from a single molecule is essential to reconstruct localization in maximum likelihood *** performance reaching nearly conventional MINFLUX's,the proposed raster-scanning MINFLUX can inspire researchers expertized in STED or confocal setup to quickly transform to MINFLUX and develop for further exploring on bio-specimens or optical applications.

关键词： scanning excitation stabilization

Fractional Smoothness of Some Stochastic Integrals

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Acta Mathematica Sinica,English Series 2007年第6期23卷 1053-1058页

作者： peng xiE xi Cheng ZHANG Department of Mathematics Huazhong University of Science and Technology Wuhan 430074 P. R. China

We study the fractional smoothness in the sense of Malliavin calculus of stochastic integrals of the form ∫0^1Ф（Xs）dXs, where Xs is a semimartingale and Ф belongs to some fractional Sobolev space over R.

关键词： fractional Sobolev space stochastic integral interpolation

Fault Identification for Shear-Type Structures Using Low-Frequency Vibration Modes

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Computer Modeling in Engineering & Sciences 2024年第3期138卷 2769-2791页

作者： Cuihong Li Qiuwei Yang xi peng School of Civil Engineering Shaoxing UniversityShaoxing312000China School of Civil and Transportation Engineering Ningbo University of TechnologyNingbo315211China Engineering Research Center of Industrial Construction in Civil Engineering of Zhejiang Ningbo University of TechnologyNingbo315211China

Shear-type structures are common structural forms in industrial and civil buildings,such as concrete and steel frame *** diagnosis of shear-type structures is an important topic to ensure the normal use of *** main drawback of existing damage assessment methods is that they require accurate structural finite element models for damage ***,for many shear-type structures,it is difficult to obtain accurate *** order to avoid finite elementmodeling,amodel-freemethod for diagnosing shear structure defects is developed in this *** method only needs to measure a few low-order vibration modes of the *** proposed defect diagnosis method is divided into two *** the first stage,the location of defects in the structure is determined based on the difference between the virtual displacements derived from the dynamic flexibility matrices before and after *** the second stage,damage severity is evaluated based on an improved frequency sensitivity *** innovations of this method lie in two *** first innovation is the development of a virtual displacement difference method for determining the location of damage in the shear *** second is to improve the existing frequency sensitivity equation to calculate the damage degree without constructing the finite *** has been verified on a numerical example of a 22-story shear frame structure and an experimental example of a three-story steel shear *** on numerical analysis and experimental data validation,it is shown that this method only needs to use the low-order modes of structural vibration to diagnose the defect location and damage degree,and does not require finite element *** proposed method should be a very simple and practical defect diagnosis technique in engineering practice.

关键词： Fault diagnosis shear steel structure vibration mode dynamic flexibility frequency sensitivity

Temporal and spatial characteristics of dissolved organic carbon in the Wujiang River,Southwest China

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Acta Geochimica 2017年第4期36卷 598-604页

作者： xi peng Baoli Wang Yanchuang Zhao State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550002China Institute of Surface-Earth System Science Tianjin UniversityTianjin 300072China Key Laboratory of Digital Earth Science Institute of RemoteSensing and Digital EarthChinese Academy of SciencesBeijing 100094China

River systems play an important role in the global carbon cycle. Rivers transport carbon to the ocean and also affect the carbon cycle in the coastal ocean. The flux from land to the ocean is thought to be a very important part of the land carbon budget. To investigate the effect of dam-building on dissolved organic carbon(DOC)in rivers, three reservoirs of different trophic states in the Wujiang basin, Guizhou Province, were sampled twice per month between May 2011 and May 2012. Temporal and spatial distributions of DOC in the reservoirs and their released waters were studied. It was found that different factors controlled DOC in river water, reservoir water, and released water. DOC in the rivers tended to be affected by primary production. For reservoirs, the main controlling factors of DOC concentration varied by trophic state. For the mesotrophic Hongjiadu Reservoir, the effect of primary production on DOC concentration was obvious. For the eutrophic Dongfengdu Reservoir and the hypereutrophic Wujiangdu Reservoir, primary production was not significant and DOC came instead from soil and plant litter.

关键词： Carbon cycle Dissolved organic carbon Dam-building effect The Wujiang River

Microscopy: looking into the mirror

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Light(Science & Applications) 2018年第1期7卷 989-991页

作者： Xusan Yang peng xi Department of Biomedical Engineering College of EngineeringPeking UniversityBeijingChina

Mirrors can create a virtual excitation source for optical microscopy,which can greatly enhance the spatiotemporal resolution of different fluorescence microscopy techniques,thus advancing toward longterm live cell *** recent decades,many new discoveries have been obtained using novel optical microscopic techniques,such as confocal,multiphoton,super resolution,and light sheet microscopies,which have attracted intensive interest from biologists working in various ***,advances in live cell fluorescence microscopy are facing multiple challenges,such as low resolution,poor signal-to-background ratio(SBR),insufficient imaging speed,and ***,these grand challenges share a common solution:*** placing a reflective mirror after an objective,the beam can be reflected,and a“virtual”excitation source can be generated without additional *** conceptually simple approach provides an easy solution to the abovementioned challenges,such as greater signal,better contrast,improved optical section ability at relative low cost,and facilitating live cell imaging with improved spatial resolution at a high speed.

关键词： mirror excitation mentioned

Chinese Word Segmentation via BiLSTM+Semi-CRF with Relay Node

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Journal of Computer Science & Technology 2020年第5期35卷 1115-1126页

作者： Nuo Qun Hang Yan xi-peng Qiu Xuan-Jing Huang School of Computer Science Fudan UniversityShanghai 200433China Shanghai Key Laboratory of Intelligent Information

Semi-Markov conditional random fields(Semi-CRFs)have been successfully utilized in many segmentation problems,including Chinese word segmentation(CWS).The advantage of Semi-CRF lies in its inherent ability to exploit properties of segments instead of individual elements of *** its theoretical advantage,Semi-CRF is still not the best choice for CWS because its computation complexity is quadratic to the sentenced *** this paper,we propose a simple yet effective framework to help Semi-CRF achieve comparable performance with CRF-based models under similar computation ***,we first adopt a bi-directional long short-term memory(BiLSTM)on character level to model the context information,and then use simple but effective fusion layer to represent the segment ***,to model arbitrarily long segments within linear time complexity,we also propose a new model named *** direct modeling of segments makes the combination with word features easy and the CWS performance can be enhanced merely by adding publicly available pre-trained word *** on four popular CWS datasets show the effectiveness of our proposed *** source codes and pre-trained embeddings of this paper are available on https://***/fastnlp/fastNLP/.

关键词： Semi-Markov conditional random field(Semi-CRF) Chinese word segmentation bi-directional long short-term memory deep learning