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A deep feed-forward neural network for damage detection in functionally graded carbon nanotube-reinforced composite plates using modal kinetic energy

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Frontiers of Structural and Civil Engineering 2021年第6期15卷 1453-1479页

作者： Huy Q.LE Tam T.TRUONG d.dinh-cong T.NGUYEN-THOI division of Computational Mathematics and Engineering Institute for Computational ScienceTon Duc Thang UniversityHo Chi Minh City 700000Vietnam Faculty of Civil Engineering Ho Chi Minh City University of TransportHo Chi Minh City 700000Vietnam division of Construction Computation Institute for Computational ScienceTon Duc Thang UniversityHo Chi Minh City 700000Vietnam Faculty of Civil Engineering Ton Duc Thang UniversityHo Chi Minh City 700000Vietnam

This paper proposes a new deep Feed-forward Neural Network(dFNN)approach for damage detection in functionally graded carbon nanotube-reinforced composite(FG-CNTRC)*** the proposed approach,the dFNN model is developed based on a data set containing 20000 samples of damage scenarios,obtained via finite element(FE)simulation,of the FG-CNTRC *** elemental modal kinetic energy(MKE)values,calculated from natural frequencies and translational nodal displacements of the structures,are utilized as input of the dFNN model while the damage locations and corresponding severities are considered as *** state-of-the art Exponential Linear Units(ELU)activation function and the Adamax algorithm are employed to train the dFNN ***,in order to enhance the performance of the dFNN model,the mini-batch and early-stopping techniques are applied to the training process.A trial-and-error procedure is implemented to determine suitable parameters of the network such as the number of hidden layers and the number of neurons in each *** accuracy and capability of the proposed dFNN model are illustrated through two distinct configurations of the CNT-fibers constituting the FG-CNTRC plates including uniform distribution(Ud)and functionally graded-V distribution(FG-Vd).Furthermore,the performance and stability of the dFNN model with the consideration of noise effects on the input data are also *** results indicate that the proposed dFNN model is able to give sufficiently accurate damage detection outcomes for the FG-CNTRC plates for both cases of noise-free and noise-influenced data.

关键词： damage detection deep feed-forward neural networks functionally graded carbon nanotube-reinforced composite plates modal kinetic energy

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depth-Guided Vision Transformer With Normalizing Flows for Monocular 3d Object detection

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IEEE/CAA Journal of Automatica Sinica 2024年第3期11卷 673-689页

作者： cong Pan Junran Peng Zhaoxiang Zhang the Center for Research on Intelligent Perception and Computing(CRIPAC) National Laboratory of Pattern Recognition(NLPR)Institute of AutomationChinese Academy of Sciences(CASIA)Beijing 100190 the School of Future Technology University of Chinese Academy of Sciences(UCAS)Beijing 100049China the Huawei Inc. Beijing 100085China IEEE the Institute of Automation Chinese Academy of Sciences(CASIA)Beijing 100190 the University of Chinese Academy of Sciences(UCAS) Beijing 100049 the Centre for Artificial Intelligence and Robotics Hong Kong Institute of Science&Innovation Chinese Academy of Sciences(HKISI CAS)Hong Kong 999077China

Monocular 3d object detection is challenging due to the lack of accurate depth *** methods estimate the pixel-wise depth maps from off-the-shelf depth estimators and then use them as an additional input to augment the RGB ***-based methods attempt to convert estimated depth maps to pseudo-LidAR and then use LidAR-based object detectors or focus on the perspective of image and depth fusion ***,they demonstrate limited performance and efficiency as a result of depth inaccuracy and complex fusion mode with *** from these approaches,our proposed depth-guided vision transformer with a normalizing flows(NF-dVT)network uses normalizing flows to build priors in depth maps to achieve more accurate depth *** we develop a novel Swin-Transformer-based backbone with a fusion module to process RGB image patches and depth map patches with two separate branches and fuse them using cross-attention to exchange information with each ***,with the help of pixel-wise relative depth values in depth maps,we develop new relative position embeddings in the cross-attention mechanism to capture more accurate sequence ordering of input *** method is the first Swin-Transformer-based backbone architecture for monocular 3d object *** experimental results on the KITTI and the challenging Waymo Open datasets show the effectiveness of our proposed method and superior performance over previous counterparts.

关键词： Monocular 3d object detection normalizing flows Swin Transformer

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Underwater RGB-d imaging system with millimetric precision

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Science China(Information Sciences) 2024年第10期67卷 383-385页

作者： Yajun GAO Yang cong Xu TANG Mingxue LI State Key Laboratory of Robotics Shenyang Institute of Automation Chinese Academy of Sciences Institutes for Robotics and Intelligent Manufacturing Chinese Academy of Sciences University of Chinese Academy of Sciences College of Automation Science and Engineering South China University of Technology

In recent years, underwater fine three-dimensional reconstruction technology has emerged as a focal point in research, exhibiting extensive potential applications, particularly in underwater archaeology and resource e... 详细信息

关键词： SINGLE CAMERA

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Quasi-2d weak lensing cosmological constraints using the PdF-SYM method

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 44-58页

作者： Zhenjie Liu Jun Zhang Hekun Li Zhi Shen cong Liu department of Astronomy Shanghai Jiao Tong UniversityShanghai 200240China Shanghai Key Laboratory for Particle Physics and Cosmology Shanghai 200240China Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China

Cosmic shear statistics,such as the two-point correlation function(2PCF),can be evaluated with the PdF-SYM method instead of the traditional weighted-sum *** makes use of the full PdF information of the shear estimators,and does not require weightings on the shear estimators,which can in principle introduce additional systematic *** work presents our constraints on S8and?mfrom the shear-shear correlations using the PdF-SYM *** data we use is from the z-band images of the dark Energy Camera Legacy Survey(dECa LS),which covers about 10000 deg2with more than 100 million *** shear catalog is produced by the Fourier Quad method,and well tested on the real data itself with the field-distortion *** main approach is called quasi-2d as we do use the photo-z information of each individual galaxy,but without dividing the galaxies into redshift *** mainly use galaxy pairs within the redshift interval between 0.2 and 1.3,and the angular range from 4.7 to 180 *** analysis yields S8=0.762±0.026 and?m=0.234±0.075,with the baryon effects and the intrinsic alignments *** results are robust against redshift *** check the consistency of our results by deriving the cosmological constraints from auto-correlations ofγ1andγ2separately,and find that they are consistent with each other,but the constraints from theγ1component are much weaker than that fromγ*** implies a much worse data quality ofγ1,which is likely due to additional shear uncertainties caused by CCd electronics(according to the survey strategy of dECa LS).We also perform a pure 2d analysis,which gives S8=0.81_(-0.04)^(+0.03)and?m=0.25_(-0.05)^(+0.06).Our findings demonstrate the potential of the PdF-SYM method for precision cosmology.

关键词： weak lensing shear-shear correlations cosmological parameters observations analysis

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High-precision modeling of tide-induced 3-d magnetic field and analysis of geomagnetic satellite orbit requirements

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Science China Earth Sciences 2024年第1期67卷 165-178页

作者： Zhengyong REN cong YANG Hongbo YAO Xu TANG Jingtian TANG Keke ZHANG Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring Ministry of Education Central South UniversityChangsha 410083China Hunan Key Laboratory of Nonferrous Resources and Geological Hazards Exploration Changsha 410083China School of Geosciences and Info-Physics Central South UniversityChangsha 410083China State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and TechnologyMacao 999078China

Ground-based magnetic observatories and geomagnetic satellites can observe the induced magnetic field generated by the motion of seawater containing sodium and chlorine *** the three-dimensional(3-d)spatial distribution of tide-induced magnetic fields(TIMF)is crucial for inverting the electrical conductivity structure of the oceanic *** also serves as an essential basis for designing optimal geomagnetic observatories and satellite ***,existing methods for simulating TIMF suffer from limitations in inaccurately modeling realistic coastlines,heterogeneous land and sea surface properties,and complex deep Earth structures,thereby the interpretational level of TIMF data is *** overcome this issue,we developed a tetrahedral-based finite element method for simulating TIMF,which can efficiently approximate realistic coastlines,heterogeneous land and sea surface properties,and complex deep Earth ***,we derived the boundary value problem for the seawater motion-induced electromagnetic field,which was solved using the vector finite element method based on tetrahedral ***,using the latest ocean depth and seafloor sediment layer models,we constructed a 3-d conductivity model of the Earth,which includes realistic coastlines,heterogeneous land and sea conductivity *** then computed the TIMF using the M_(2)tidal source as an example and validated our method by comparing it with results obtained from spherical harmonic finite element and integral equation ***,utilizing the computed high-precision M_(2),N_(2),and O1 TIMF signals,we marked global observatories capable of observing strong M_(2),N_(2),and O1 TIMF signals and predicted alternative stations suitable for tide signal ***,we calculated TIMF at heights of 450 and 200 km for the Macao Science Satellite 1 and its subsequent *** results indicate that the amplitude of the tidal-induced magnetic field at

关键词： Ocean motional induction Electromagnetic induction Ocean tides Geomagnetic satellite Macao Science Satellite 1

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Femtosecond laser 3d printed micro objective lens for ultrathin fiber endoscope

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Fundamental Research 2024年第1期4卷 123-130页

作者： Bozhe Li Changrui Liao Zhihao Cai Jie Zhou cong Zhao Liqing Jing Jiaqi Wang cong Xiong Lei Xu Ying Wang Yiping Wang Key Laboratory of Optoelectronic devices and Systems of Ministry of Education/Guangdong Province College of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen 518060China Shenzhen Key Laboratory of Photonic devices and Sensing Systems for Internet of Things Guangdong and Hong Kong Joint Research Centre for Optical Fibre SensorsShenzhen UniversityShenzhen 518060China School of Electronic and Communication Engineering Shenzhen Polytechnic UniversityShenzhen 518055China

The most important optical component in an optical fiber endoscope is its objective *** achieve a high imaging performance level,the development of an ultra-compact objective lens is thus the key to an ultra-thin optical fiber *** this work,we use femtosecond laser 3d printing to develop a series of micro objective lenses with different optical *** imaging resolution and field-of-view performances of these printed micro objective lenses are investigated via both simulations and *** the first time,multiple micro objective lenses with different fields of view are printed on the end face of a single imaging optical fiber,thus realizing the perfect integration of an optical fiber and objective *** work demonstrates the considerable potential of femtosecond laser 3d printing in the fabrication of micro-optical systems and provides a reliable solution for the development of an ultrathin fiber endoscope.

关键词： Femtosecond laser Two-photon polymerization 3d printing Micro objective lens Fiber endoscope

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Adsorption and sensing characteristics of insulating gas C4F7N on 3d late transition metal-phthalocyanine:Theoretical and experimental study

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High Voltage 2024年第4期9卷 870-878页

作者： dachang Chen Ziang Zheng cong Zhang Yi Luo Song Xiao Qing Miao Ke Liu Beibei Xiao School of Electrical and Electronic Engineering Wuhan Polytechnic UniversityWuhanChina Beijing International S&T Cooperation Base for Plasma Science and Energy Conversion Institute of Electrical EngineeringChinese Academy of SciencesBeijingChina School of Electrical Engineering and Automation Wuhan UniversityWuhanChina School of Energy and Power Engineering Jiangsu University of Science and TechnologyZhenjiangChina

Heptafluoroisobutyronitrile(C_(4)F_(7)N)is being considered as a promising alternative to the greenhouse gas SF6 in the electrical ***,its biotoxicity necessitates the development of gas sensing technology to detect leaked C_(4)F_(7)N.A combination of density functional theory and experiments was employed to evaluate the adsorption and sensing performance of different metal-phthalocyanines as potential sensing materials for C_(4)F_(7)N *** study included exploring adsorption configurations with adsorption energies,electron transfer,and adsorption distance,as well as comparisons of electronic properties,electron distribution,and density of states(dOS)among the ***,gas sensing experiments were conducted using different MPcs to detect 25-100 ppm C_(4)F_(7)*** results revealed that Mn-Pc,Fe-Pc,Co-Pc,and Zn-Pc exhibited considerable chemical interactions,while Ni-Pc and Cu-Pc showed weaker adsorption *** findings were further elucidated based on the electron density and dOS of atomic ***,gas sensing experiments indicated that Co-Pc demonstrated a higher response compared to Fe-Pc at the same concentration of C_(4)F_(7)***,the theoretical and experimental insights offer valuable guidance for C_(4)F_(7)N detection and provide a systematic approach to screen and explore organometallic polymer-based gas sensors applicable in various fields.

关键词： adsorption phthalocyanine Adsorption

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A Comprehensive Survey of Recent Transformers in Image,Video and diffusion Models

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Computers, Materials & Continua 2024年第7期80卷 37-60页

作者： dinh Phu Cuong Le dong Wang Viet-Tuan Le College of Computer Science and Electronic Engineering Hunan UniversityChangsha410082China Faculty of Information Technology Yersin University of Da LatDa Lat66100Vietnam Faculty of Information Technology Ho Chi Minh City Open UniversityHo Chi Minh City722000Vietnam

Transformer models have emerged as dominant networks for various tasks in computer vision compared to Convolutional Neural Networks(CNNs).The transformers demonstrate the ability to model long-range dependencies by utilizing a self-attention *** study aims to provide a comprehensive survey of recent transformerbased approaches in image and video applications,as well as diffusion *** begin by discussing existing surveys of vision transformers and comparing them to this ***,we review the main components of a vanilla transformer network,including the self-attention mechanism,feed-forward network,position encoding,*** the main part of this survey,we review recent transformer-based models in three categories:Transformer for downstream tasks,Vision Transformer for Generation,and Vision Transformer for *** also provide a comprehensive overview of recent transformer models for video tasks and diffusion *** compare the performance of various hierarchical transformer networks for multiple tasks on popular benchmark ***,we explore some future research directions to further improve the field.

关键词： Transformer vision transformer self-attention hierarchical transformer diffusion models

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Photoswitchable Spiropyridine Enabled Photoactuation of Polymeric Hydrogels under Physiological pH Conditions

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Chinese Journal of Polymer Science 2024年第10期42卷 1602-1609,I0015页

作者： cong Liao Meng-Qi du Chuang Li Key Laboratory of Precision and Intelligent Chemistry Department of Polymer Science and EngineeringUniversity of Science and Technology of ChinaAnhui230026China

The incorporation of molecular switches into polymer networks has been a powerful approach for the development of functional polymer materials that display macroscopic actuation and function enabled directly by molecular ***,such materials sometimes require harsh conditions to perform their functions,and the design of new molecular photoswitches that can function under physiological conditions is highly ***,we report the design and synthesis of a spiropyridine-based photoswitchable hydrogel that exhibits light-driven actuation at physiological *** to its high p Ka,spiropyridine maintains its ring-open protonated form at neutral pH,and the resulting hydrogel remains in a swollen *** irradiation with visible light,the ring closure of spiropyridine leads to a decrease in the charge and a reduction in the volume of the *** contracted gel could spontaneously recover to its expanding state in the dark,and this process is highly dynamic and reversible when the light is switched on and ***,the hydrogel shows switchable fluorescence in response to visible *** deformation is observed in the hydrogel thin films upon irradiation from one ***,the independence of this spiropyridine hydrogel from the acidic environment makes it biotolerant and shows excellent *** biocompatible spiropyridine hydrogel might have important biorelated applications in the future.

关键词： Spiropyridine photowitch Polymer hydrogel Photoactuation Physiological pH Biocompatibility

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Engineering a high-barrier d-f single-molecule magnet centered with hexagonal bipyramidal dy(Ⅲ)unit

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Science China Chemistry 2024年第10期67卷 3291-3298页

作者： Wei deng Chan-Ying Yao Yan-cong Chen Ying-Qian Zhou Shan-Nan du Jun-Liang Liu Ming-Liang Tong Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education School of ChemistryInstitute of Green Chemistry and Molecular EngineeringGuangdong Basic Research Center of Excellence for Functional Molecular EngineeringSun Yat-sen UniversityGuangzhou 510006China

In the pursuit of high-performance single-molecule magnets(SMMs),incorporating intramolecular magnetic coupling emerges as a pivotal *** these,d-f SMMs have garnered significant attention due to their remarkable versatility,which lies in their ability to tune coordination environments and facilely substitute metal ***,achieving performance-centric d-f SMMs through the synergistic interplay between highly anisotropic f ions and d-f magnetic interactions remains a formidable *** mononuclear hexagonal bipyramidal(d_(6h))dy^(Ⅲ)SMMs have been successfully isolated,the exploration of d-f SMMs featuring d_(6h)-lanthanide metal centers remains uncharted *** this study,we employed planar bipodal ligands in conjunction with“staple-like”axial phenoxide ligands to synthesize the first hexagonal bipyramidal d-f ***,this compound exhibits alternating-current magnetic susceptibilities peaking up to 68 K with an energy barrier surpassing 1,200 K,thus establishing a new benchmark within the heterometallic d-f SMM landscape inclusive of complexes with diamagnetic d metals and paramagnetic f ***,the ferromagnetic interaction at the d-f sites engenders oscillating relaxation times contingent on the magnetic field—a characteristic distinct from mononuclear *** findings shed light on a deliberate design approach for d-f SMMs,emphasizing the cooperative utilization of high-barrier lanthanide modules alongside d ions through magnetic *** synergy significantly enhances and diversifies the magnetic dynamics of these intriguing molecular systems.

关键词： single-molecule magnets magnetic coupling crystal engineering hexagonal bipyramid energy barrier

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