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Three dimensional shear wave velocity structure of crust and upper mantle in South China Sea and its adjacent regions by surface waveform inversion 被引量:22
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作者 曹小林 朱介寿 +2 位作者 赵连锋 曹家敏 洪学海 《地震学报》 CSCD 北大核心 2001年第2期113-124,共12页
We assembled approximately 328 seismic records. The data set was from 4 digitally recording long-period and broadband stations of CDSN. We carried out the inversion based on the partitioned waveform inversion (PWI). I... We assembled approximately 328 seismic records. The data set was from 4 digitally recording long-period and broadband stations of CDSN. We carried out the inversion based on the partitioned waveform inversion (PWI). It partitions the large-scale optimization problem into a number of independent small-scale problems. We adopted surface waveform inversion with an equal block (2((2() discretization in order to acquire the images of shear velocity structure at different depths (from surface to 430 km) in the crust and upper-mantle. The resolution of all these anomalies has been established with (check-board( resolution tests. These results show significant difference in velocity, lithosphere and asthenosphere structure between South China Sea and its adjacent regions. 展开更多
关键词 面波波形 分块波形反演 三维S波速度结构 中国数字地震台网 “检验板”法 岩石圈
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Time-variant reliability analysis of three-dimensional slopes based on Support Vector Machine method 被引量:4
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作者 陈昌富 肖治宇 张根宝 《Journal of Central South University》 SCIE EI CAS 2011年第6期2108-2114,共7页
In the reliability analysis of slope, the performance functions derived from the most available stability analysis procedures of slopes are usually implicit and cannot be solved by first-order second-moment approach. ... In the reliability analysis of slope, the performance functions derived from the most available stability analysis procedures of slopes are usually implicit and cannot be solved by first-order second-moment approach. A new reliability analysis approach was presented based on three-dimensional Morgenstem-Price method to investigate three-dimensional effect of landslide in stability analyses. To obtain the reliability index, Support Vector Machine (SVM) was applied to approximate the performance function. The time-consuming of this approach is only 0.028% of that using Monte-Carlo method at the same computation accuracy. Also, the influence of time effect of shearing strength parameters of slope soils on the long-term reliability of three-dimensional slopes was investigated by this new approach. It is found that the reliability index of the slope would decrease by 52.54% and the failure probability would increase from 0.000 705% to 1.966%. In the end, the impact of variation coefficients of c andfon reliability index of slopes was taken into discussion and the changing trend was observed. 展开更多
关键词 slope engineering Morgenstern-Price method three dimension Support Vector Machine time-variant reliability
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Automatic three-dimensional reconstruction based on four-view stereo vision using checkerboard pattern 被引量:5
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作者 XIONG Jie ZHONG Si-dong +1 位作者 LIU Yong TU Li-fen 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第5期1063-1072,共10页
An automatic three-dimensional(3D) reconstruction method based on four-view stereo vision using checkerboard pattern is presented. Mismatches easily exist in traditional binocular stereo matching due to the repeatable... An automatic three-dimensional(3D) reconstruction method based on four-view stereo vision using checkerboard pattern is presented. Mismatches easily exist in traditional binocular stereo matching due to the repeatable or similar features of binocular images. In order to reduce the probability of mismatching and improve the measure precision, a four-camera measurement system which can add extra matching constraints and offer multiple measurements is applied in this work. Moreover, a series of different checkerboard patterns are projected onto the object to obtain dense feature points and remove mismatched points. Finally, the 3D model is generated by performing Delaunay triangulation and texture mapping on the point cloud obtained by four-view matching. This method was tested on the 3D reconstruction of a terracotta soldier sculpture and the Buddhas in the Mogao Grottoes. Their point clouds without mismatched points were obtained and less processing time was consumed in most cases relative to binocular matching. These good reconstructed models show the effectiveness of the method. 展开更多
关键词 three-dimensional reconstruction four-view STEREO VISION CHECKERBOARD pattern DENSE point
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Obstacle avoidance method of three-dimensional obstacle spherical cap 被引量:5
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作者 YANG Xiuxia ZHANG Yi ZHOU Weiwei 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2018年第5期1058-1068,共11页
Focusing on obstacle avoidance in three-dimensional space for unmanned aerial vehicle(UAV), the direct obstacle avoidance method in dynamic space based on three-dimensional velocity obstacle spherical cap is proposed,... Focusing on obstacle avoidance in three-dimensional space for unmanned aerial vehicle(UAV), the direct obstacle avoidance method in dynamic space based on three-dimensional velocity obstacle spherical cap is proposed, which quantifies the influence of threatening obstacles through velocity obstacle spherical cap parameters. In addition, the obstacle avoidance schemes of any point on the critical curve during the multi-obstacles avoidance are given. Through prediction, the insertion point for the obstacle avoidance can be obtained and the flight path can be replanned. Taking the Pythagorean Hodograph(PH) curve trajectory re-planning as an example, the three-dimensional direct obstacle avoidance method in dynamic space is tested. Simulation results show that the proposed method can realize the online obstacle avoidance trajectory re-planning, which increases the flexibility of obstacle avoidance greatly. 展开更多
关键词 three-dimensional direct space obstacle avoidance velocity obstacle cone velocity obstacle spherical cap
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Three-dimensional positions of scattering centers reconstruction from multiple SAR images based on radargrammetry 被引量:3
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作者 钟金荣 文贡坚 +1 位作者 回丙伟 李德仁 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第5期1776-1789,共14页
A method and procedure is presented to reconstruct three-dimensional(3D) positions of scattering centers from multiple synthetic aperture radar(SAR) images. Firstly, two-dimensional(2D) attribute scattering centers of... A method and procedure is presented to reconstruct three-dimensional(3D) positions of scattering centers from multiple synthetic aperture radar(SAR) images. Firstly, two-dimensional(2D) attribute scattering centers of targets are extracted from 2D SAR images. Secondly, similarity measure is developed based on 2D attributed scatter centers' location, type, and radargrammetry principle between multiple SAR images. By this similarity, we can associate 2D scatter centers and then obtain candidate 3D scattering centers. Thirdly, these candidate scattering centers are clustered in 3D space to reconstruct final 3D positions. Compared with presented methods, the proposed method has a capability of describing distributed scattering center, reduces false and missing 3D scattering centers, and has fewer restrictionson modeling data. Finally, results of experiments have demonstrated the effectiveness of the proposed method. 展开更多
关键词 multiple synthetic aperture radar(SAR) images three-dimensional scattering center position reconstruction radargrammetry
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Risk Assessment of Coal Mine Water Hazard Based on Three-Dimensional Model of Geology and Underground Space 被引量:1
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作者 Kai Zhang~1,Ming Huang~1,Bin Tang~2,Fan Cui~1 1.Laboratory of Coal Resources and Mine Safety,China University of Mining and Technology,Beijing 100083,China. 2.China Water Investment Co.Ltd,Beijing 100053,China 《地学前缘》 EI CAS CSCD 北大核心 2009年第S1期279-279,共1页
Mine safety have top-five disasters,which including the water,gas,fire,dust and geological dynamic disaster.The coal mine water disaster is one of the important factors which restricted the development of China’s coa... Mine safety have top-five disasters,which including the water,gas,fire,dust and geological dynamic disaster.The coal mine water disaster is one of the important factors which restricted the development of China’s coal production.It is showed by statistics that 60%of mine accidents are affected by groundwater,which not only result in the production losses,casualties and a variety of 展开更多
关键词 DISASTER risk assessment three-dimensionAL model of GEOLOGY and UNDERGROUND space emergency RESCUE
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New three-dimensional guidance law for BTT missiles based on differential geometry and Lie-group 被引量:2
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作者 Shuangchun Peng Liang Pan Tianjiang Hu Lincheng Shen 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2011年第4期684-690,共7页
A new non-decoupling three-dimensional guidance law is proposed for bank-to-turn (BTT) missiles with the motion coupling problem. In this method, the different geometry is taken for theoretically modeling on B-IT mi... A new non-decoupling three-dimensional guidance law is proposed for bank-to-turn (BTT) missiles with the motion coupling problem. In this method, the different geometry is taken for theoretically modeling on B-IT missiles' motion within the threedimensional style without information loss, and meanwhile, Liegroup is utilized to describe the line-of-sight (LOS) azimuth when the terminal angular constraints are considered. Under these cir- cumstances, a guidance kinematics model is established based on differential geometry. Then, corresponding to no terminal angular constraint and terminal angular constraints, guidance laws are re- spectively designed by using proportional control and generalized proportional-derivative (PD) control in SO(3) group. Eventually, simulation results validate that this developed method can effectively avoid the complexity of pure Lie-group method and the information loss of the traditional decoupling method as well. 展开更多
关键词 three-dimensional guidance law differential geometry Lie-group control bank-to-turn (BTT).
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Splitting Based Scheme for Three-dimensional MHD with Dual Time Stepping 被引量:1
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作者 FU Huazheng FENG Xueshang 《空间科学学报》 CAS CSCD 北大核心 2015年第1期9-17,共9页
A new hybrid numerical scheme of combining an E-CUSP(Energy-Convective Upwind and Split Pressure) method for the fluid part and the Constrained Transport(CT) for the magnetic induction part is proposed.In order to avo... A new hybrid numerical scheme of combining an E-CUSP(Energy-Convective Upwind and Split Pressure) method for the fluid part and the Constrained Transport(CT) for the magnetic induction part is proposed.In order to avoid the occurrence of negative pressure in the reconstructed profiles and its updated value,a positivity preserving method is provided.Furthermore,the MHD equations are solved at each physical time step by advancing in pseudo time.The use of dual time stepping is beneficial in the computation since the use of dual time stepping allows the physical time step not to be limited by the corresponding values in the smallest cell and to be selected based on the numerical accuracy criterion.This newly established hybrid scheme combined with positivity preserving method and dual time technique has demonstrated the accurateness and robustness through numerical experiments of benchmark problems such as the 2D Orszag-Tang vortex problem and the3 D shock-cloud interaction problem. 展开更多
关键词 SPLITTING BASED SCHEME three-dimensionAL MHD Dual time STEPPING
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Three-dimensional Simulation of Reverberation Chamber Using Finite-element Time-domain Method 被引量:1
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作者 DU Lei WANG Song +2 位作者 CUI Yaozhong WANG Qingguo PAN Yun 《高电压技术》 EI CAS CSCD 北大核心 2013年第12期2889-2893,共5页
关键词 三维模拟 时域法 有限元 混响室 几何建模 标准偏差 雷达散射截面 低频响应
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Precision Analysis of Three Dimension Free Curves Nanofabrication
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作者 ZHENG Wei 1, WANG Er-qi 2, SONG De-hui 2, W B LEE 3, S andy TO 3 (1. Department of Mechatronics, Xiamen University, 2. College of Computer and Information Engineering, Xiamen University, Xiamen 361005, China 3. Ultra-Precision Machining Centre, Department of Industrial and Systems Engin eering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China) 《厦门大学学报(自然科学版)》 CAS CSCD 北大核心 2002年第S1期279-,共1页
Three dimension free curves find wide applications in engineering. There is no problem to express them exactly mathematically, but th e reportage has not been done on the investigation of precision analysis of thre e-... Three dimension free curves find wide applications in engineering. There is no problem to express them exactly mathematically, but th e reportage has not been done on the investigation of precision analysis of thre e-dimension free curves nanofabrication. Nanofabrication Precision includes the geometrical precision and the precision of driving system (below simply cal led the system precision). This paper submits the precision analysis method of c urve normal vector to analyze geometrical precision. Take an aspherical surf ace for example, it can be fitted and constructed by tensor product parameter cu rves, such as linear drawing curves, straight veins curves, rotating curves, swe eping curves, DUCT curves and Geomap curves. Then the curves of the aspherical s urface is iterated and modified to select the best fitted curves of the aspheric al surface. Finally, the geometrical precision of perfect approximate aspherical surface fitting has been sought. This kind of geometrical fitting construction is very important. Another is the system precision, which contains axial position precision, line p recision, and twisting and swinging precision, etc. The paper adopts the theory of precision optimum match (Prof. Wang Er-qi first put forward in 19 83) to allocate precision optimumly. The minimum cost is used as an objective fu nction, and weight method matches the precision. To obtain the optimum match combination of the minimum cost design parameters and every composing element t olerance, the precision is iterated and sought optimumly to design the system op timumly. The theoretical analysis shows that it’s feasible to control three dim ension free curves nanofabrication within nanometer scale precision. 展开更多
关键词 three dimension curves PRECISION optimum match advanced manufacturing technology micro-/nano-technology
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Rheological characteristics of drug-loaded microemulsions and their printability in three dimensional printing systems
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作者 余灯广 闫伟霞 +3 位作者 朱思君 李雪莲 Branford-white Chris 朱利民 《Journal of Central South University》 SCIE EI CAS 2008年第S1期88-92,共5页
Rheological properties of microemulsions(MEs) and their printability in three dimensional printing(3DP) systems were investigated.A series of MEs with different contents of oil phase were prepared using sonication met... Rheological properties of microemulsions(MEs) and their printability in three dimensional printing(3DP) systems were investigated.A series of MEs with different contents of oil phase were prepared using sonication method with ibuprofen as model drug and soybean lecithin as emulfier.Stationary and transient rheological properties of MEs were investigated by ARES-SRF using concentric cylinders measuring systems.3DP systems with piezoelectric drop-on-demand print heads were employed to test the printability of the MEs.Results demonstrate that the apparent viscosity and dynamic linear viscoelastic regions of the MEs are the most important parameters for continuous and stable printing of MEs by 3DP.The incorporation of drug in the MEs has little influence on the MEs' stationary rheological behaviors and dynamic viscoelasticity,but the concentration of oil phase has a strong influence on them.The rheological property of binder liquids has a close relationship with their printability in 3DP system. 展开更多
关键词 three-dimensional PRINTING RHEOLOGICAL property MICROEMULSIONS PRINTABILITY APPARENT VISCOSITY
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Research on three-dimensional trajectory parameter measurement of industrial products
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作者 Guo Qing Guo Ming +1 位作者 Hu Jingquan Hu Hongzhi 《仪器仪表学报》 EI CAS CSCD 北大核心 2007年第6期999-1002,共4页
Three-dimensional trajectory parameter measurement of industrial products is the key technical criteria that drives the product qualification.It has recently become one of the hotspots in the measurement field.This pa... Three-dimensional trajectory parameter measurement of industrial products is the key technical criteria that drives the product qualification.It has recently become one of the hotspots in the measurement field.This paper presents a method for measuring the eyeglass frame parameters using the inner trajectory as measurement object.The three-dimensional parameters can be measured and calculated from top view and front view.The preprocessing is performed to ensure the reliability of data acquisition.The necessary derivation and explanation for formulas of important parameters are provided.A standard square board is used as the template and is measured multi-times to verify the measurement method.The experimental data are processed and the type A uncertainty is calculated,which concludes that the measurement results are convincible and comply with the product standard,and the proposed method is correct and the design requirements are met. 展开更多
关键词 工业产品 三维轨迹参数 曲率 镜片结构 测量
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Study on the Binding Interaction of Nanomaterials Tio_2 with Bovine Serum Albumin by Three-Dimensional Fluorescence Spectrometry (TDFS)
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作者 LIU Mingxue DONG Fa-qin +6 位作者 SUN Shiyong YI Wei XIONG Xing GUO Yuting LIU Yuanyuan HUANG Ting GOU Qingbi 《矿物学报》 CAS CSCD 北大核心 2013年第S1期60-60,共1页
Although scientific and policy bodies have stated that nanomaterials are not intrinsically toxic, there is interest in evaluating if and how many engineered nanomaterials may do harm to the health of mankind and the e... Although scientific and policy bodies have stated that nanomaterials are not intrinsically toxic, there is interest in evaluating if and how many engineered nanomaterials may do harm to the health of mankind and the ecological environment. The interaction between nano-TiO2 and bovine serum albumin (BSA) was studied by using TDFS and UV methods in this research. 展开更多
关键词 NANOMATERIAL TiO2 BSA three-dimensional FLUORESCENCE SPECTROMETRY interaction
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IF signals simulation of three-dimensional radar
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作者 Zhang Wei Wang Xuegang Zhu Zhaoda 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2008年第3期486-492,共7页
Based on the analysis of the principles of frequency-phase scanning 3-D (three-dimensional) radar and the scattering mechanism of 3-D radar, the target and clutter IF (intermediate frequency) signals model of freq... Based on the analysis of the principles of frequency-phase scanning 3-D (three-dimensional) radar and the scattering mechanism of 3-D radar, the target and clutter IF (intermediate frequency) signals model of frequencyphase scanning 3-D radar is presented. The IF signals model of different channels of 3-D radar is presented in one simple formula in which complex waveform effects are considered. The simulation results obtained during tests are also provided in the end. 展开更多
关键词 SIMULATION three-dimensional radar IF signal frequency-phase scanning.
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Forming mechanism of three-dimensional integral fin based on flat surface
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作者 向建化 段吉安 +3 位作者 周海波 张春良 刘贵云 周超 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第5期1660-1666,共7页
To improve heat-transfer performance, a novel integral three-dimensional fin-structure on the plat surface was presented to increase the evaporation efficiency. The three-dimensional fin-structure is composed of a spi... To improve heat-transfer performance, a novel integral three-dimensional fin-structure on the plat surface was presented to increase the evaporation efficiency. The three-dimensional fin-structure is composed of a spiral micro-groove and multi radial micro-grooves. Both ploughing-extrusion(P-E) and stamping were used to form the integral-fins with a connection between radial and circumferential directions. Based on the SEM results, the relationships among P-E speed v P-E, rotational speed np and feed fp, and among interference length Li, stamping feed angle θc and stamping depth ac were analyzed. The effects of processing parameters on the groove morphology and the matching relationship between parameters were also discussed. The integral finned surface with micro-grooves and cracks can be obtained under such processing conditions: P-E depth ap=0.3 mm, ac=0.3 mm, the interval of helical groove dp=1.24 mm, θc=2° and np=50 r/min. 展开更多
关键词 three-dimensional integral fin ploughing-extrusion STAMPING micro groove enhanced boiling
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Three-Dimensional Space Interpolation of Grey / Depth Image Sequence-A New Technique of Computer Graphics Synthesis
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作者 Wang Xincheng, Zhu Weile, Zhu Xiaokun and Gu DerenChengdu University of Electronic Science and Technology, Chengdu 610054 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 1993年第3期70-77,共8页
This paper advances a three-dimensional space interpolation method of grey / depth image sequence, which breaks free from the limit of original practical photographing route. Pictures can cruise at will in space. By u... This paper advances a three-dimensional space interpolation method of grey / depth image sequence, which breaks free from the limit of original practical photographing route. Pictures can cruise at will in space. By using space sparse sampling, great memorial capacity can be saved and reproduced scenes can be controlled. To solve time consuming and complex computations in three-dimensional interpolation algorithm, we have studied a fast and practical algorithm of scattered space lattice and that of 'Warp' algorithm with proper depth. By several simple aspects of three dimensional space interpolation, we succeed in developing some simple and practical algorithms. Some results of simulated experiments with computers have shown that the new method is absolutely feasible. 展开更多
关键词 Grey / depth image three-dimensional space interpolation Computer graphics synthesis Algorithms.
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计算机模拟手术结合3D打印技术在复杂骨折手术中的应用进展 被引量:2
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作者 杨立宇 郭文娟 +2 位作者 叶飞 张一奇 巴根 《中国医科大学学报》 北大核心 2025年第2期167-170,177,共5页
以计算机辅助设计为基础的3D打印技术能够快速制作三维立体模型,清晰显示骨折部位的解剖结构、类型和破裂程度,为了解骨折情况提供全方位的视觉化手段。该技术还能帮助医生设计个性化的植入物,选择定制的手术导向板和固定螺丝。手术医... 以计算机辅助设计为基础的3D打印技术能够快速制作三维立体模型,清晰显示骨折部位的解剖结构、类型和破裂程度,为了解骨折情况提供全方位的视觉化手段。该技术还能帮助医生设计个性化的植入物,选择定制的手术导向板和固定螺丝。手术医生通过术前模拟操作,对手术方案进行优化,提高手术的准确性和效果。本文总结了计算机模拟手术结合3D打印技术在多种骨科手术中的应用情况,并广泛阐述了3D打印技术在临床骨科领域的巨大应用潜力。 展开更多
关键词 计算机辅助设计 3D打印 复杂骨折
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双目立体视觉技术及其在智慧农业中的应用研究进展 被引量:2
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作者 杨学军 钟金彪 +3 位作者 林开颜 吴军辉 陈杰 司慧萍 《农业工程学报》 北大核心 2025年第1期27-39,共13页
双目立体视觉技术作为一种获取现实世界立体感知的重要方法,可以实现农业场景目标的三维定位和点云重建,提取立体三维信息,具有很大的应用潜力。该文介绍了双目立体视觉技术的应用流程,包括双目视觉标定、极线校正、立体匹配等方面,以... 双目立体视觉技术作为一种获取现实世界立体感知的重要方法,可以实现农业场景目标的三维定位和点云重建,提取立体三维信息,具有很大的应用潜力。该文介绍了双目立体视觉技术的应用流程,包括双目视觉标定、极线校正、立体匹配等方面,以及相关研究进展;综合近期文献,探讨了双目立体视觉技术在果实定位采摘与地图导航、生长参数测量和病害识别与施药等农业领域最新的应用。综述结果表明,双目立体视觉技术在农业中定位、测量和识别均具有较高精度,但仍面临模型复杂、场景受限、数据集少和立体匹配缺少评价标准等问题。展望该技术在农业领域的未来发展,应着重从算法设计与优化、智能辅助平台搭建、数据集构建和评价体系完善等方面开展研究探索。 展开更多
关键词 双目视觉 智慧农业 立体匹配 作物参数测量 三维目标定位 病害识别
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锂离子电池电化学-热-应力三维耦合建模及应力分布研究 被引量:2
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作者 刘素贞 陈永博 +2 位作者 张闯 徐志成 金亮 《电工技术学报》 北大核心 2025年第4期1307-1322,共16页
锂离子电池工作过程中产生的扩散诱导应力和热应力,会导致电池内部发生多种形式的力学损伤,进而导致电池容量减少和寿命缩短,准确获取锂离子电池应力分布和演变情况对研究电池老化机制至关重要。因此亟须研究一种能够获取锂离子电池工... 锂离子电池工作过程中产生的扩散诱导应力和热应力,会导致电池内部发生多种形式的力学损伤,进而导致电池容量减少和寿命缩短,准确获取锂离子电池应力分布和演变情况对研究电池老化机制至关重要。因此亟须研究一种能够获取锂离子电池工作过程中内部应力分布及演化的方法,以揭示应力对其寿命的影响,进一步提高设计和优化的效率。该文首先研究锂离子电池电化学、热、力的多物理场耦合机制,建立锂离子电池电化学-热-应力三维耦合模型;其次搭建锂离子电池充放电实验平台并测试不同倍率下电池的表面温度和表面压力,验证了所建模型的有效性;最后通过验证后的模型分析了电池在不同倍率恒流充电过程中内部应力分布及演化规律。该模型可以有效获取锂离子电池在运行过程中的应力分布情况,有助于电池失效机理研究,为电池的优化设计和应用提供参考。 展开更多
关键词 锂离子电池 三维耦合模型 扩散诱导应力 热应力 应力分布
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Current situation and trend of fabrication technologies for three-dimensional metamaterials
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作者 Xiaoyong Tian Lixian Yin Dichen Li 《光电工程》 CAS CSCD 北大核心 2017年第1期119-119,共1页
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