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Characteristics of three-dimensional oceanic eddy in the Southern Ocean from 2021 to 2023 认领 引用
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作者 Tao Jiang Weizeng Shao +3 位作者 Yuyi Hu Xingwei Jiang Qingping Zou Yongliang Wei 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2026年第4期1-16,共16页
This study explores the three-dimensional(3-D)characteristics of oceanic eddies in the Southern Ocean from 2021 to 2023.Copernicus Marine Environment Monitoring Service(CMEMS)GLORYS12V1 product,which provides daily cu... This study explores the three-dimensional(3-D)characteristics of oceanic eddies in the Southern Ocean from 2021 to 2023.Copernicus Marine Environment Monitoring Service(CMEMS)GLORYS12V1 product,which provides daily current field data at a(1/12)°grid resolution,is used to identify eddies with radii>10 km.Additionally,the daily sea level anomaly product from Haiyang-2(HY-2)altimeters is used to detect mesoscale eddies with radii>40 km.GLORYS12V1 detects over ten times more surface eddies than HY-2,likely due to its higher spatial and temporal resolution,which allows better identification of smaller-scale features.Both eddy radius and eddy kinetic energy(EKE)differences between layers decrease with depth.At 0.5 m,EKE is lower than at 300–600 m,where it stabilizes.Over 90%of eddies at these depths show center deflection angles under 3°,defined as the angular offset between eddy centers in adjacent layers relative to the vertical(0°)axis.In a 3-D eddy,the center may shift with depth due to physical processes,causing non-zero center deflection angles between layers.Below 300 m,eddy radius differences are more frequently under 20 km than in the upper 0.5–300 m,where baroclinic instability amplifies,and barotropic instability suppresses cross-layer variability.The influence of both instabilities weakens with depth.In the upper ocean(0.5–300 m),baroclinic instability increases the angular offsets between eddy centers.In contrast,barotropic instability reduces these offsets.At 300–600 m,both promote better vertical alignment,indicating greater structural stability.Overall,this study enhances the understanding of the vertical structure and dynamics of oceanic eddies in the Southern Ocean. 展开更多
关键词 three-dimensional characteristics oceanic eddy Southern Ocean
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Investigation on three-dimensional unsteady flow characteristics during TBCC inlet mode transition using fast-responding PSP 认领 引用
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作者 Liang CHEN Yue ZHANG +4 位作者 Xu LIU Huijun TAN Haicheng ZHU Mingchi PANG Ziyun WANG 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2026年第7期231-245,共15页
This study investigates the three-dimensional unsteady flow characteristics during the mode transition process of a Turbine-Based Combined Cycle(TBCC)inlet under side-wall constraints.The research focuses on an over-u... This study investigates the three-dimensional unsteady flow characteristics during the mode transition process of a Turbine-Based Combined Cycle(TBCC)inlet under side-wall constraints.The research focuses on an over-under TBCC inlet with a design transition Mach number of 3.5 and a transition speed of 1.65(°)/s,in a wind tunnel with incoming flow Mach number 2.9.A novel approach combining fast-responding Pres sure-Sensitive Paint(PSP)measurement technique with high-speed schlieren imaging and dynamic pressure transducers was employed to achieve the three-dimensional dynamic measurement of shock-dominated flow evolution during mode transition.The Proper Orthogonal Decomposition(POD)method was utilized to reveal the threedimensional dynamic mechanisms of two typical unsteady flows following the high-speed duct unstart.When the duct is fully open,the flow separation caused by throat congestion exhibits significant span wise asymmetry under side-wall constraints.The phase difference between separation vortices in the central and corner regions induces a low-frequency oscillation of the separation shock,predominantly characterized by span wise fluctuations.Conversely,in the hysteresis state,the corner effect is substantially diminished,leading to increased spanwise flow uniformity.The separation shock oscillation converts to a streamwise motion mode,primarily governed by the selfexcited oscillation of the downstream separation bubble and the shoulder shock train.This study provides comprehensive clarification of the multi-scale flow coupling mechanism during the TBCC inlet mode transition process from a three-dimensional spatiotemporal evolution perspective.The findings offer crucial theoretical support for the dynamic stability control of hypersonic combined cycle inlets. 展开更多
关键词 Fast-responding PSP Hysteresis characteristics Mode transition Over-under TBCC inlet Three-dimensional unsteady flows
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Three-Dimensional and Cross-sectional Characteristics of Normal Grain Growth Based on Monte Carlo Simulation 认领 引用 被引量：3
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作者 Xiaoyan Song Guoquan Liu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS 1998年第3期129-133,139,共5页
An appropriate Monte Carlo method was developed to simulate the three-dimensional normal grain growth more completely.Comparative investigation on the three-dimensional and the cross-sectional characteristics of norma... An appropriate Monte Carlo method was developed to simulate the three-dimensional normal grain growth more completely.Comparative investigation on the three-dimensional and the cross-sectional characteristics of normal grain growth was done.It was found that the time exponent of grain growth determined from cross-section exhibits the same rule of increasing slowly with time and approaching the theoretical value n=0.5 of steadygrain growth as the three-dimensional(3-D)system.From change of the number of grains per unit area with timemeasured in cross-section,the state of 3-D normal grain growth may be predicted.The gtain size distribution incross-section is different from that in 3-D system and can not express the evolution characteristic of the 3-D distribution.Furthermore,there exists statistical connection between the topological parameters in cross-section and thosein three-dimensions. 展开更多
关键词 Monte Carlo simulation normal grain growth three-dimension cross-section characteristics
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Three-dimensional Electromagnetic Characteristics Analysis of Novel Linear Synchronous Motor under Lateral and Yaw Conditions of MAGLEV 认领 引用 被引量：4
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作者 Gang Lv Zhixuan Zhang Xiaodong Li 《CES Transactions on Electrical Machines and Systems》 CSCD 2022年第1期29-36,共8页
Dynamic stability analysis of superconducting electro-dynamic maglev train under lateral and yawing motion condition is the key research content.The novel three-dimensional electromagnetic model of integrated linear s... Dynamic stability analysis of superconducting electro-dynamic maglev train under lateral and yawing motion condition is the key research content.The novel three-dimensional electromagnetic model of integrated linear synchronous motor in electro-dynamic maglev train with yawing operation condition is proposed,which can not only simultaneously achieve the propulsion,levitation and guidance performances of maglev vehicle,but also analyze the dynamic stability performance of train with yawing condition.The three-dimensional analytical method is introduced for analyzing the electromagnetic force characteristics of the linear synchronous motor with the yawing operation condition.Firstly,the topology structure and operation principle of the linear synchronous motor with yawing attitude are proposed.Secondly,the three-dimensional analytical model and expressions of electromagnetic characteristics are obtained by equivalent circuit method and Fourier decomposition method,such as levitation force,guidance force,propulsion force and yawing torque,etc.Finally,the three-dimensional electromagnetic characteristics of the linear synchronous motor are calculated under yawing operation conditions of maglev train,and the correctness of the analytical theory is verified by the finite element analysis and measured data on the test line. 展开更多
关键词 electro-dynamic maglev system linear synchronous motor propulsion levitation and guidance three-dimensional electromagnetic characteristics
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Shear fracture behavior and fracture fractal characteristics of granite under adverse effect of cyclic heating 认领 引用
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作者 JIANG Tian-qi CHEN Bing +5 位作者 ZHANG Qing-song SHEN Bao-tang BAI Ji-wen LIU Ren-tai CHEN Meng-jun SASAOKA Takashi 《Journal of Central South University》 SCIE EI CAS CSCD 2025年第9期3405-3426,共22页
Deep geothermal extraction processes expose rock masses to frequent and significant temperature fluctuations. Developing a comprehensive understanding of the shear fracture mechanisms and crack propagation behaviors i... Deep geothermal extraction processes expose rock masses to frequent and significant temperature fluctuations. Developing a comprehensive understanding of the shear fracture mechanisms and crack propagation behaviors in rocks under the influence of cyclic heating is imperative for optimizing geothermal energy extraction. This study encompasses several critical aspects under cyclic heating conditions, including the assessment of stress distribution states, the characterization of two-dimensional fracture paths, the quantitative analysis of three-dimensional damage characteristics on fracture surfaces, and the determination of the fractal dimension of debris generated after the failure of granite. The test results demonstrate that cyclic heating has a pronounced adverse effect on the physical and mechanical properties of granite. Consequently, stress tends to develop and propagate in a direction perpendicular to the two-dimensional fracture path. This leads to an increase in the extent of tensile damage on the fracture surface and accelerates the overall rock failure process. This increases the number of small-sized debris, raises the fractal dimension, and enhances the rock’s rupture degree. In practical enhanced geothermal energy extraction, the real-time monitoring of fracture propagation within the reservoir rock mass is achieved through the analysis of rock debris generated during the staged fracturing process. 展开更多
关键词 progressive thermal damage stress distribution characteristics two-dimensional fracture path three-dimensional fracture surface failure characteristics fractal dimension
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Analysis on Three-dimensional Structure and Echo Characteristic Quantity of a Supercell Storm 认领 引用
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作者 FU Shuang-xi HE Jin-mei CHEN Tian-yu 《Meteorological and Environmental Research》 2011年第8期38-42,共5页
[Objective] The research aimed to study three-dimensional structure and echo characteristic quantity of a supercell storm in central Gansu on May 30,2005.[Method] By monitoring data of Lanzhou CINRAD/CC Doppler radar,... [Objective] The research aimed to study three-dimensional structure and echo characteristic quantity of a supercell storm in central Gansu on May 30,2005.[Method] By monitoring data of Lanzhou CINRAD/CC Doppler radar,the three-dimensional structure characteristics of a rare supercell storm which happened in central Gansu on May 30,2005 were analyzed.We tried to reveal three-dimensional structure and echo characteristic index of supercell storm in the northeast of Qinghai-Tibet Plateau,and find reason of rare heavy hail appearance.[Result] The large-scale strong storm was formed by the common effect of Mongolia cold vortex,low-level jet and ground cold front.When the development of main echo was mature,on reflectivity factor map,it presented obvious inverted 'V' shaped structure in left front of low-level storm,typical hooked and 'person'-type echo characteristics in the right rear.The bounded weak echo zone(vault) in low level corresponded with strong echo overhanging body in high level.It surpassed 60 dBz in the strong reflectivity factor zone.It presented one weak meso-cyclone on corresponding radial velocity map.The jumped increase characteristic of VIL could be as one of indices for judging that hail started to grow.Almost all storms(VILD ≥4.0 g/m3) had more obvious indication significance than VIL for judging heavy hail(diameter ≥20 mm).[Conclusion] The research provided reference for nowcasting of strong convection weather and artificial hail suppression. 展开更多
关键词 Supercell Storm Three-dimensional structure Echo characteristic quantity China
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THE CHARACTERISTIC FINITE DIFFERENCE METHOD FOR THREE-DIMENSIONAL MOVING BOUNDARY VALUE PROBLEM 认领 引用
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作者 袁益让 赵卫东 《Numerical Mathematics A Journal of Chinese Universities(English Series)》 1998年第2期133-144,共12页
The software for oil-gas transport and accumulation is to describe the history of oil-gas transport and accumulation in basin evolution. It is of great value in rational evaluation of prospecting and exploiting oil-ga... The software for oil-gas transport and accumulation is to describe the history of oil-gas transport and accumulation in basin evolution. It is of great value in rational evaluation of prospecting and exploiting oil-gas resources. The mathematical model can be discribed as a coupled system of nonlinear partial differential equations with moving boundary value problem. For a generic case of the three-demensional bounded region, bi this thesis, the effects of gravitation、buoyancy and capillary pressure are considered, we put forward a kind of characteristic finite difference schemes and make use thick and thin grids to form a complete set, and of calculus of vaviations, the change of variable, the theory of prior estimates and techniques, Optimal order estimates in l^2 norm are derived for the error in approximate assumption, Thus we have completely solved the well-known theoretical problem proposed by J. Douglas, Jr. 展开更多
关键词 Three-dimensional moving boundary gravitation buoyancy and capillary pressure characteristic finite difference optimal order estimate in l^2.
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Three-Dimensional Conjugate Tooth Surface Design and Contact Analysis of Harmonic Drive with Double-Circular-Arc Tooth Profle 认领 引用 被引量：4
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作者 Chaosheng Song Feihong Zhu +1 位作者 Xinzi Li Xuesong Du 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2023年第5期248-265,共18页
A three-dimensional conjugate tooth surface design method for Harmonic Drive with a double-circular-arc tooth profle is proposed. The radial deformation function of the fexspline (FS), obtained through Finite Element ... A three-dimensional conjugate tooth surface design method for Harmonic Drive with a double-circular-arc tooth profle is proposed. The radial deformation function of the fexspline (FS), obtained through Finite Element (FE) analysis, is incorporated into the kinematics model. By analyzing the FS tooth enveloping process, the optimization of the overlapping conjugate tooth profle is achieved. By utilizing the hobbing process, the three-dimensional machinable tooth surface of FS can be acquired. Utilizing the coning deformation of the FS, simulations are conducted to analyze the multi-section assembly and meshing motion of the machinable tooth surface. The FE method is utilized to analyze and compare the loaded contact characteristics. Results demonstrate that the proposed design method can achieve an internal gear pair consisting of a circular spline with a spur gear tooth surface and the FS with a machinable tooth surface. With the rated torque, approximately 24% of the FS teeth are engaged in meshing, and more than 4/5 of the tooth surface in the axial direction carries the load. The contact patterns, maximum contact pressure, and transmission error of the machinable tooth surface are 227.2%, 40.67%, and 71.24% of those on the spur gear tooth surface, respectively. It clearly demonstrates exceptional transmission performance. 展开更多
关键词 Three-dimensional conjugate tooth surface Coning deformation Double-circular-arc tooth profle Harmonic Drive Contact characteristics
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Three-dimensional flow field mathematical model inside the pilot stage of the deflector jet servo valve 认领 引用 被引量：1
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作者 Shuang-lu LI Yao-bao YIN +1 位作者 Jiang-yang YUAN Sheng-rong GUO 《Journal of Zhejiang University-SCIENCE A》 SCIE EI CAS CSCD 2022年第10期795-806,共12页
A new flow field mathematical model is proposed to describe accurately the flow field structure and calculate the static characteristics of the pilot stage in a deflector jet servo valve(DJSV). The flow field is divid... A new flow field mathematical model is proposed to describe accurately the flow field structure and calculate the static characteristics of the pilot stage in a deflector jet servo valve(DJSV). The flow field is divided into five regions, a 3D turbulent jet is adopted to describe the free jet region, and a velocity distribution expression of the jet is proposed. The jet entrainment model is put forward in the pressure recovery region to describe the coupling relationship between the pressure in the receiving chamber and the jet flow. The static characteristics, including pressure-flow characteristics, pressure characteristics,and flow characteristics of the pilot stage are obtained. The flow field structure and the static characteristics are verified by finite element analysis(FEA) and experiment, respectively, and the mathematical model results are in good agreement with the experimental and simulation results. 展开更多
关键词 Deflector jet servo valve(DJSV) Pilot stage Three-dimensional jets Jets entrainment Static characteristics Mathematical model
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Three-Dimensional Bursting Phenomena in Meander Channel 认领 引用 被引量：3
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作者 刘小谢 白玉川 《Transactions of Tianjin University》 EI CAS 2013年第1期17-24,共8页
Experiments were conducted in a U-shaped open-channel flume with the intention of investigating the bursting phenomena in the meander channel. The experimental results of the secondary flow fields and the Reynolds she... Experiments were conducted in a U-shaped open-channel flume with the intention of investigating the bursting phenomena in the meander channel. The experimental results of the secondary flow fields and the Reynolds shear stress distributions show that the velocity and velocity fluctuation in the transverse direction are not negligible. Moreover, the bursting process is investigated using the three-dimensional quadrant analysis, which is more accurate than using the traditional two-dimensional quadrant analysis for the meandering channel. It is obtained from the experimental results that the internal group of events occurs more frequently than the external group, particularly the internal ejection and internal sweep events. In addition, the transition probabilities of the movements, which are defined as the changes of events from the current situation to the next situation in a time series, show that the stable organizations of events are the most possible movements, whereas the cross organizations of events have the least possible movements. 展开更多
关键词 meander channel bursting phenomena turbulent characteristics three-dimension
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Three-dimensional numerical simulation of the flow past a circular cylinder based on LES method 认领 引用 被引量：5
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作者 陈海龙 戴绍士 +1 位作者 李佳 姚熊亮 《Journal of Marine Science and Application》 2009年第2期110-116,共7页
The hydrodynamic characteristics of a rigid, single, circular cylinder in a three dimensional, incompressible, uniform cross flow were calculated using the large-eddy simulation method of CFX5. Solutions to the three ... The hydrodynamic characteristics of a rigid, single, circular cylinder in a three dimensional, incompressible, uniform cross flow were calculated using the large-eddy simulation method of CFX5. Solutions to the three dimensional N-S equations were obtained by the finite volume method. The focus of this numerical simulation was to research the characteristics of pressure distribution （drag and litt forces） and vortex tubes at high Reynolds numbers. The results of the calculations showed that the forces at every section in the spanwise direction of the cylinder were symmetrical about the middle section and smaller than the forces calculated in two dimensional cases. Moreover, the flow around the cylinder obviously presents three dimensional characteristics. 展开更多
关键词 LES method three-dimensional flow past circular cylinder hydrodynamic characteristics
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Integration system research and development for three-dimensional laser scanning information visualization in goaf 认领 引用 被引量：4
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作者 罗周全 黄俊杰 +2 位作者 罗贞焱 汪伟 秦亚光 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第7期1985-1994,共10页
An integration processing system of three-dimensional laser scanning information visualization in goaf was developed. It is provided with multiple functions, such as laser scanning information management for goaf, clo... An integration processing system of three-dimensional laser scanning information visualization in goaf was developed. It is provided with multiple functions, such as laser scanning information management for goaf, cloud data de-noising optimization, construction, display and operation of three-dimensional model, model editing, profile generation, calculation of goaf volume and roof area, Boolean calculation among models and interaction with the third party soft ware. Concerning this system with a concise interface, plentiful data input/output interfaces, it is featured with high integration, simple and convenient operations of applications. According to practice, in addition to being well-adapted, this system is favorably reliable and stable. 展开更多
关键词 goaf laser scanning visualization integration system 1 Introduction The goaf formed through underground mining of mineral resources is one of the main disaster sources threatening mine safety production [1,2]. Effective implementation of goaf detection and accurate acquisition of its spatial characteristics including the three-dimensional morphology, the spatial position as well as the actual boundary and volume, are important basis to analyze, predict and control disasters caused by goaf. In recent years, three-dimensional laser scanning technology has been effectively applied in goaf detection [3,4]. Large quantities of point cloud data that are acquired for goaf by means of the three-dimensional laser scanning system are processed relying on relevant engineering software to generate a three-dimensional model for goaf. Then, a general modeling analysis and processing instrument are introduced to perform subsequent three-dimensional analysis and calculation [5,6]. Moreover, related development is also carried out in fields such as three-dimensional detection and visualization of hazardous goaf, detection and analysis of unstable failures in goaf, extraction boundary acquisition in stope, visualized computation of damage index, aided design for pillar recovery, and three-dimensional detection
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Characteristics and distribution of microstructures in high pressure die cast alloys with X-ray microtomography:A review 认领 引用
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作者 Hai-dong Zhao Xue-ling Wang +2 位作者 Qian Wan Wen-hui Bai Fei Liu 《China Foundry》 SCIE EI CAS CSCD 2024年第5期427-444,共18页
Al and Mg alloy high pressure die castings(HPDC)are increasingly used in automotive industries.The microstructures in the castings have decisive effect on the casting mechanical properties,in which the microstructure ... Al and Mg alloy high pressure die castings(HPDC)are increasingly used in automotive industries.The microstructures in the castings have decisive effect on the casting mechanical properties,in which the microstructure characteristics are fundamental for the investigation of the microstructure-property relation.During the past decade,the microstructure characteristics of HPDC Al and Mg alloys,especially micro-pores andα-Fe,have been investigated from two-dimensional(2D)to threedimensional with X-ray micro-computed tomography(μ-CT).This paper provides an overview of the current understanding regarding the 3D characteristics and formation mechanisms of microstructures in HPDC alloys,their spatial distributions,and the impact on mechanical properties.Additionally,it outlines future research directions for the formation and control of heterogeneous microstructures in HPDC alloys. 展开更多
关键词 high pressure die casting microstructure three-dimensional characteristics distribution Al and Mg alloys
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Research on CT characteristics reconstruction technology 认领 引用
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作者 赵英亮 王黎明 韩焱 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2016年第2期129-135,共7页
The traditional computed tomography(CT)reconstruction methods are noisy,low resolution,poor contrast,and generally not suitable to detect the smaller flaws.Besides,the filter design is also difficult.The CT characteri... The traditional computed tomography(CT)reconstruction methods are noisy,low resolution,poor contrast,and generally not suitable to detect the smaller flaws.Besides,the filter design is also difficult.The CT characteristics reconstruction technology was brought forward to improve in these aspects,which is defined to directly reconstruct the characteristics of the projection for the best requirements not the overall image quality.The two-dimension(2D)and three-dimension(3D)CT characteristics reconstruction algorithm were firstly introduced,then by detailed analysis,experimental results and comparsion of parameters calculated,its advantages in keeping better high-frequency feature,better noise immunity,short time-consuming and easier design are verified. 展开更多
关键词 three-dimension(3D) computed tomography(CT)reconstruction characteristics reconstruction technology
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Study on short-range numerical forecasting of ocean current in the East China Sea—II.Three-dimensional diagnostic model and its application in the Bohai Sea 认领 引用
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作者 Zhao Jinping and Shi Maochong 《Acta Oceanologica Sinica》 SCIE CAS 1994年第2期173-188,共16页
In this paper,a tbree-dimensional (3-D) baroclinic diagnostic model for short-range numerical forecast is proposed to calculate the monthly averaged flow field in the Bohai Sea. By using the model and monthly averaged... In this paper,a tbree-dimensional (3-D) baroclinic diagnostic model for short-range numerical forecast is proposed to calculate the monthly averaged flow field in the Bohai Sea. By using the model and monthly averaged tempeature and salinity date, monthly barotropic and baroclinic flow field are calculated,and 2-D and 3-D characteristics of flow are described and demonstrated. On the basis of the analysis of the modelling results and the observed temperature,salinity and wind data,the monthly and seasonal characteristics and generation mechanism of circulation in the Bohai Sea are also discussed. It is pointed out in this paper that in spring and autumn,the monthly averaged flow fields are not representative, for the wind direction varies in a wide range and the averaged wind field is much weaker than the instantaneous one. These results show the reliability of the model for describing the monthly characteristics in numerical forecast of ocean current. 展开更多
关键词 Diagnostic model monthly averaged flow field the Bohai Sea circulation three-dimensional characteristics
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Study on the Effect of Transvaginal Three-dimensional Ultrasound in the Diagnosis of Uterine Malformation 认领 引用
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作者 GANNa 《外文科技期刊数据库（文摘版）医药卫生》 2022年第7期215-218,共4页
Objective: to analyze the effect of transvaginal three-dimensional ultrasound in the diagnosis of uterine malformation. Methods: a total of 100 patients with suspected uterine malformations were investigated. All pati... Objective: to analyze the effect of transvaginal three-dimensional ultrasound in the diagnosis of uterine malformation. Methods: a total of 100 patients with suspected uterine malformations were investigated. All patients were admitted to the group from February 2018 to March 2022. All patients underwent hysteroscopy, two-dimensional transvaginal ultrasound and three-dimensional transvaginal ultrasound. Taking hysteroscopy as the gold standard, the accuracy, specificity and sensitivity of different methods were compared, and the characteristics of three-dimensional transvaginal ultrasound imaging were analyzed. Results: in all patients, hysteroscopy, two-dimensional transvaginal ultrasound and three-dimensional transvaginal ultrasound showed 70, 44 and 66 cases of uterine malformation, respectively, and 30, 56 and 34 cases of non-uterine malformation were detected. The sensitivity of three-dimensional ultrasound was 94.29%(66/70), and that of two-dimensional ultrasound was 62.86%(44/70). The specificity of the two methods was 100%(30/30), and there was no significant difference between the two groups (P > 0.05). The accuracy of three-dimensional ultrasound examination was 96%(96 cases), and that of two-dimensional ultrasound examination was 74%(74 cases). There was significant difference between the two groups (P < 0.05). Conclusion: compared with two-dimensional ultrasound, transvaginal three-dimensional ultrasound has higher accuracy and sensitivity in the diagnosis of uterine malformation, clear imaging, and can be used to judge the specific manifestations of uterine malformation. It has a positive effect on the clinical treatment of diseases, so it is recommended to be popularized. 展开更多
关键词 transvaginal three-dimensional ultrasound uterine malformation specificity sensitivity accuracy imaging characteristics
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Effect of initial fracture angle on the failure pattern and gas flow channel of sandstone under multistage loading 认领 引用
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作者 Quanle Zou Feixiang Lv +4 位作者 Zihan Chen Qingsong Li Jianjun Zhao Qican Ran Qingmiao Li 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2026年第3期2142-2157,共16页
After coal seam mining,the overlying rock strata above the goaf are subjected to long-term stress and eventually undergo failure.Under mining-induced disturbances,the strata develop fractures at various angles,which s... After coal seam mining,the overlying rock strata above the goaf are subjected to long-term stress and eventually undergo failure.Under mining-induced disturbances,the strata develop fractures at various angles,which significantly influence failure modes and the morphology of gas flow channels.This study employed multistage loading experiments,numerical simulations,three-dimensional reconstruction,and image recognition to investigate the fragmentation process of rocks with different initial fracture angles under multistage loading.The results show that variations in the initial fracture angle affect the transmission of contact forces among rock particles.As the angle increases,the transmission pattern shifts from a uniform distribution to one extending along the direction of the fracture.Rocks with small initial fracture angles tend to experience tensile-dominated failure,with most of the material subjected to longitudinal loading,resulting in reduced strength.Fractures propagate from the central region of the initial fracture,producing a complex internal fracture network.The proportion of fracture channels varies considerably across regions,creating multiple zones of velocity variation in the gas flow.In contrast,rocks with large initial fracture angles are more susceptible to shear failure,with the primary load-bearing zones aligned along the inclined fracture direction.As a result,the influence on surrounding regions is limited,improving the rock's load-bearing capacity under multistage loading.In these cases,the distribution and proportion of fracture channels become more uniform,promoting more stable gas flow within the channels.Overall,these findings provide theoretical insights into how initial fracture angles govern rock failure patterns and gas flow characteristics. 展开更多
关键词 Multistage loading Initial fracture angle Failure pattern Gas flow characteristics Three-dimensional fracture reconstruction
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Three-dimensional morphological characteristics measurement of ankle joint based on computed tomography image post-processing 认领 引用 被引量：12
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作者 CHEN Yan-xi LU Xiao-ling +6 位作者 BI Gang YU Xiao HAO Yi-li ZHANG Kun ZOU Li-ling MEI Jiong YU Guang-rong 《Chinese Medical Journal》 SCIE CAS CSCD 2011年第23期3912-3918,共7页
As precise positioning of ankle radiography is not possible,quantitative measurement of all syndesmotic parameters on repeated ankle X-ray films may be of little value.The purpose of this study was to provide a set of... As precise positioning of ankle radiography is not possible,quantitative measurement of all syndesmotic parameters on repeated ankle X-ray films may be of little value.The purpose of this study was to provide a set of scientific and objective evaluation criteria for assessing the quality of ankle fracture reduction accurately and reliably by an intelligent combining three-dimensional(3-D)computed tomography(CT)measurement model.Methods From June 2008 to March 2011,all the thin-slice CT images of 100 cases(50 males and 50 females)with normal ankle joint scanned by 16-slice spiral CT were collected.Two-dimensional(2-D)and 3-D images of ankle joints were generated by using multiple planar reconstruction(MPR)and surface shaded display(SSD)respectively.The relevant parameters about bone structures and their relationship were measured and analyzed based on 3-D topological narrow division technique and 3-D measurement techniques combining essential elements of point,line and surface.Results In this study,the mean distance from lateral malleolus tip to talocrural articular surface,the tip of medial malleolus anterior colliculus to talocrural articular surface and lateral malleolus tip to the tip of medial malleolus anterior colliculus were(22.83±1.12)mm,(12.84±1.09)mm,and(61.18±2.03)mm respectively in male group,and(20.16±1.00)mm,(10.30±1.05)mm and(53.00±1.40)mm respectively in female group.The above three parameters were correlated with gender,height and weight(P〈0.05).However,the mean perpendicular distance from lateral malleolus tip to the plane through the tip of medial malleolus anterior colliculus,the talocrural angle,later clear space,medial clear space,and the superior clear space were(9.93±0.29)mm,(10.01±0.38)°,(1.94±0.16)mm,(2.78±0.19)mm,and(3.14±0.15)mm respectively in 100 cases,were not significance correlated with gender,height and weight(P〉0.05).Conclusions This study could provide a certain amount of relevant data for the standard of injured ankle anatomical reduction and the second surgery planning after malunion.The methods of measurement are reliable,reproducible,and easy to apply in practice. 展开更多
关键词 ankle,computed tomography three-dimensional reconstruction morphological characteristics
The experimental study of hydrodynamic characteristics of the overland flow on a slope with three-dimensional Geomat 认领 引用 被引量：8
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作者 王广月 孙国瑞 +1 位作者 李建康 李炯 《Journal of Hydrodynamics》 SCIE EI CSCD 2018年第1期153-159,共7页
The hydrodynamic characteristics of the overland flow on a slope with a three-dimensional Geomat are studied for different rainfall intensities and slope gradients. The rainfall intensity is adjusted in the rainfall s... The hydrodynamic characteristics of the overland flow on a slope with a three-dimensional Geomat are studied for different rainfall intensities and slope gradients. The rainfall intensity is adjusted in the rainfall simulation system. It is shown that the velocity of the overland flow has a strong positive correlation with the slope length and the rainfall intensity, the scour depth decreases with the increase of the slope gradient for a given rainfall intensity, and the scour depth increases with the increase of the rainfall intensity for a given slope gradient, the overland flow starts with a transitional flow on the top and finishes with a turbulent flow on the bottom on the slope with the three-dimensional Geomat for different rainfall intensities and slope gradients, the resistance coefficient and the turbulent flow Reynolds number are in positively related logarithmic functions, the resistance coefficient and the slope gradient are in positively related power functions, and the trend becomes leveled with the increase of the rainfall intensity. This study provides some important theoretical insight for further studies of the hydrodynamic process of the erosion on the slope surface with a three-dimensional Geomat. 展开更多
关键词 Three-dimensional Geomat rainfall intensity slope gradient overland flow hydrodynamic characteristics
Mapping three-dimensional co-seismic surface deformations associated with the 2015 MW7.2 Murghab earthquake based on InSAR and characteristics of crustal strain 认领 引用 被引量：3
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作者 Jie GAN Jun HU +4 位作者 Zhiwei LI Changjiang YANG Jihong LIU Qian SUN Wanji ZHENG 《Science China Earth Sciences》 SCIE EI CAS CSCD 2018年第10期1451-1466,共16页
Three-dimensional(3 D) co-seismic surface deformations are of great importance to interpret the characteristics of coseismic deformations and to understand the geometries and dynamics of seismogenic faults. In this pa... Three-dimensional(3 D) co-seismic surface deformations are of great importance to interpret the characteristics of coseismic deformations and to understand the geometries and dynamics of seismogenic faults. In this paper, we propose a method for mapping 3 D co-seismic deformations based on InSAR observations and crustal strain characteristics. In addition, the search strategy of correlation points is optimized by adaptive correlation distance, which greatly improves the applicability of the proposed method in restoring deformations in decorrelation areas. Results of the simulation experiment reveal that the proposed method is superior to conventional methods in both the accuracy and completeness. The proposed method is then applied to map the 3 D co-seismic surface deformations associated with the 2015 MW7.2 Murghab earthquake using ascending and descending ALOS-2 PALSAR-2 images. The results show that the seismogenic fault is the Sarez-Karakul fault(SKF), which is dominated by NE-SW strike slips with an almost vertical dip angle. The north section and the south segment near the epicentre have obvious subsidence along with a southwestward motion in the northwest wall, and the southeast wall has northeast movement and surface uplift trend along the fault zone. The strain field of the earthquake is also obtained by the proposed method. It is found that the crustal block of the seismic area is obviously affected by dilatation and shear forces, which is in good agreement with the movement character of the sinistral slip. 展开更多
关键词 InSAR Characteristics of crustal strain Three-dimensional co-seismic deformations Murghab earthquake,ALOS-2
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