期刊文献+
共找到862,268篇文章
< 1 2 250 >
每页显示 20 50 100
Three-dimensional Modeling of Ore-forming Elements and Mineralization Prognosis for the Yechangping Mo Deposit,Henan Province,China
1
作者 DING Gaoming JI Genyuan +5 位作者 YAN Guolong XU Yongzhong WANG Kunming XIAO Chun WANG Quanle GUO Dongbao 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2024年第3期736-752,共17页
Three-dimensional geochemical modeling of ore-forming elements is crucial for predicting deep mineralization.This approach provides key information for the quantitative prediction of deep mineral localization,three-di... Three-dimensional geochemical modeling of ore-forming elements is crucial for predicting deep mineralization.This approach provides key information for the quantitative prediction of deep mineral localization,three-dimensional fine interpolation,analysis of spatial distribution patterns,and extraction of quantitative mineral-seeking markers.The Yechangping molybdenum(Mo)deposit is a significant and extensive porphyry-skarn deposit in the East Qinling-Dabie Mo polymetallic metallogenic belt at the southern margin of the North China Block.Abundant borehole data on oreforming elements underpin deep geochemical predictions.The methodology includes the following steps:(1)Threedimensional geological modeling of the deposit was established.(2)Correlation,cluster,and factor analyses post delineation of mineralization stages and determination of mineral generation sequence to identify(Cu,Pb,Zn,Ag)and(Mo,W,mfe)assemblages.(3)A three-dimensional geochemical block model was constructed for Mo,W,mfe,Cu,Zn,Pb,and Ag using the ordinary kriging method,and the variational function was developed.(4)Spatial distribution and enrichment characteristics analysis of ore-forming elements are performed to extract geological information,employing the variogram and w(Cu+Pb+Zn+Ag)/w(Mo+W)as predictive indicators.(5)Identifying the western,northwestern,and southwestern areas of the mine with limited mineralization potential,contrasted by the northeastern and southeastern areas favorable for mineral exploration. 展开更多
关键词 3D geochemical model ore-forming elements GEOSTATISTICS deep mineralization prediction Yechangping Mo deposit
下载PDF
Numerical three-dimensional modeling of earthen dam piping failure
2
作者 Zhengang Wang 《Water Science and Engineering》 EI CAS CSCD 2024年第1期72-82,共11页
A physically-based numerical three-dimensional earthen dam piping failure model is developed for homogeneous and zoned soil dams.This model is an erosion model,coupled with force/moment equilibrium analyses.Orifice fl... A physically-based numerical three-dimensional earthen dam piping failure model is developed for homogeneous and zoned soil dams.This model is an erosion model,coupled with force/moment equilibrium analyses.Orifice flow and two-dimensional(2D)shallow water equations(SWE)are solved to simulate dam break flows at different breaching stages.Erosion rates of different soils with different construction compaction efforts are calculated using corresponding erosion formulae.The dam's real shape,soil properties,and surrounding area are programmed.Large outer 2D-SWE grids are used to control upstream and downstream hydraulic conditions and control the boundary conditions of orifice flow,and inner 2D-SWE flow is used to scour soil and perform force/moment equilibrium analyses.This model is validated using the European Commission IMPACT(Investigation of Extreme Flood Processes and Uncertainty)Test#5 in Norway,Teton Dam failure in Idaho,USA,and Quail Creek Dike failure in Utah,USA.All calculated peak outflows are within 10%errors of observed values.Simulation results show that,for a V-shaped dam like Teton Dam,a piping breach location at the abutment tends to result in a smaller peak breach outflow than the piping breach location at the dam's center;and if Teton Dam had broken from its center for internal erosion,a peak outflow of 117851 m'/s,which is 81%larger than the peak outflow of 65120 m3/s released from its right abutment,would have been released from Teton Dam.A lower piping inlet elevation tends to cause a faster/earlier piping breach than a higher piping inlet elevation. 展开更多
关键词 3D dam breach model 2D shallow water equations 3D slope stability analysis Piping failure Teton Dam Quail Creek Dike
下载PDF
Current and future role of three-dimensional modelling technology in rectal cancer surgery:A systematic review 被引量:2
3
作者 Anna Przedlacka Gianluca Pellino +3 位作者 Jordan Fletcher Fernando Bello Paris P Tekkis Christos Kontovounisios 《World Journal of Gastrointestinal Surgery》 SCIE 2021年第12期1754-1769,共16页
BACKGROUND Three-dimensional(3D)modelling technology translates the patient-specific anatomical information derived from two-dimensional radiological images into virtual or physical 3D models,which more closely resemb... BACKGROUND Three-dimensional(3D)modelling technology translates the patient-specific anatomical information derived from two-dimensional radiological images into virtual or physical 3D models,which more closely resemble the complex environment encountered during surgery.It has been successfully applied to surgical planning and navigation,as well as surgical training and patient education in several surgical specialties,but its uptake lags behind in colorectal surgery.Rectal cancer surgery poses specific challenges due to the complex anatomy of the pelvis,which is difficult to comprehend and visualise.AIM To review the current and emerging applications of the 3D models,both virtual and physical,in rectal cancer surgery。METHODS Medline/PubMed,Embase and Scopus databases were searched using the keywords“rectal surgery”,“colorectal surgery”,“three-dimensional”,“3D”,“modelling”,“3D printing”,“surgical planning”,“surgical navigation”,“surgical education”,“patient education”to identify the eligible full-text studies published in English between 2001 and 2020.Reference list from each article was manually reviewed to identify additional relevant papers.The conference abstracts,animal and cadaveric studies and studies describing 3D pelvimetry or radiotherapy planning were excluded.Data were extracted from the retrieved manuscripts and summarised in a descriptive way.The manuscript was prepared and revised in accordance with PRISMA 2009 checklist.RESULTS Sixteen studies,including 9 feasibility studies,were included in the systematic review.The studies were classified into four categories:feasibility of the use of 3D modelling technology in rectal cancer surgery,preoperative planning and intraoperative navigation,surgical education and surgical device design.Thirteen studies used virtual models,one 3D printed model and 2 both types of models.The construction of virtual and physical models depicting the normal pelvic anatomy and rectal cancer,was shown to be feasible.Within the clinical context,3D models were used to identify vascular anomalies,for surgical planning and navigation in lateral pelvic wall lymph node dissection and in management of recurrent rectal cancer.Both physical and virtual 3D models were found to be valuable in surgical education,with a preference for 3D printed models.The main limitations of the current technology identified in the studies were related to the restrictions of the segmentation process and the lack of 3D printing materials that could mimic the soft and deformable tissues.CONCLUSION 3D modelling technology has potential to be utilised in multiple aspects of rectal cancer surgery,however,it is still at the experimental stage of application in this setting. 展开更多
关键词 Rectal cancer three-dimensional modelling three-dimensional printing Image-guided surgery Surgical navigation Surgical education
下载PDF
Three-Dimensional Model Test for Port Engineering with Multi-Directional Waves 被引量:1
4
作者 Yu Yuxiu Liu Shuxue Professor, State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology (DUT), Dalian 116024 Assistant Researcher, State Key Laboratory of Coastal and Offshore Engineering, DUT, Dalian 116024 《China Ocean Engineering》 SCIE EI 1994年第1期51-66,共16页
-The necessity of using irregular waves, especially multi- directional waves to conduct three-dimensional model tests for port engineering and the test method are described in this paper through an example of model te... -The necessity of using irregular waves, especially multi- directional waves to conduct three-dimensional model tests for port engineering and the test method are described in this paper through an example of model test for a port. The test results show that a deep navigation channel has a large effect on the waves in front of the breakwater near the port entrance and on the wave condition in the port. 展开更多
关键词 port engineering three-dimensional model test irregular waves multi-directional waves
下载PDF
Research on the Three-dimensional Modeling and Optimization of a Virtual Tower Crane Based on 3DS Max, Solidworks and EON Professional 被引量:2
5
作者 HOU Xiao-ting LI Chang-hua 《International Journal of Plant Engineering and Management》 2013年第1期15-19,共5页
Three-dimensional modeling of virtual hoisting machinery is the critical works to structure the system of virtual construction, and the foundation to realize intelligent and interactive virtual hoisting. Aimed at enha... Three-dimensional modeling of virtual hoisting machinery is the critical works to structure the system of virtual construction, and the foundation to realize intelligent and interactive virtual hoisting. Aimed at enhancing the requests of image quality and stability of the virtual construction scene, taking a tower crane for example. We studied the technology of three-dimensional modeling and optimization of a virtual tower crane, and a method named two-stage model optimization was put forward. This depended on the modeling stage using Solidworks and 3DS Max and the performance optimization stage in EON. The practice of software development indicates that the proposed methods of three-dimensional modeling and optimization could satisfy the performance request of virtual construction system and be popularized to other virtual system. 展开更多
关键词 3DS Max SOLIDWORKS EON Professional virtual tower crane three-dimensional modeling andoptimization virtual construction
下载PDF
Three-Dimensional Models for Analyzing the Cyclic Variations in a Lean Burn CNG Engine
6
作者 李国岫 虞育松 刘建英 《Journal of Beijing Institute of Technology》 EI CAS 2007年第3期274-278,共5页
Three-dimensional models, consisting of the flame kernel formation model, flame kernel development model and natural gas single step reaction model, are used to analyze the contribution of cyclic equivalence ratio var... Three-dimensional models, consisting of the flame kernel formation model, flame kernel development model and natural gas single step reaction model, are used to analyze the contribution of cyclic equivalence ratio variations to cyclic variations in the compressed natural gas (CNG) lean burn spark ignition engine. Computational results including the contributions of equivalence ratio cyclic variations to each combustion stage and effects of engine speed to the extent of combustion variations are discussed. It is concluded that the equivalence ratio variations affect mostly the main stage of combustion and hardly influence initial kernel development stage. 展开更多
关键词 three-dimensional model lean burn CNG engine equivalence ratio combustion cyclic variations
下载PDF
Solution and simulation algorithm of microseismic events location to three-dimensional model by comprehensive location method based on Matlab
7
作者 XIA Yuan-yuan SHAO He-song +1 位作者 LI Shi-xiong LU Jing-yu 《Journal of Coal Science & Engineering(China)》 2012年第3期254-257,共4页
The essential for microseismic monitoring is fast and accurate calculation of seismic wave source location. The precision of most traditional microseismic monitoring processes of mines, using TDOA location method in t... The essential for microseismic monitoring is fast and accurate calculation of seismic wave source location. The precision of most traditional microseismic monitoring processes of mines, using TDOA location method in two-dimensional space to position the microseismic events, as well as the accuracy of positioning microseismic events, may be reduced by the two-dimensional model and simple method, and ill-conditioned equations produced by TDOA location method will increase the positioning error. This article, based on inversion theory, studies the mathematical model of TDOA location method, polariza- tion analysis location method, and comprehensive difference location method of adding angle factor in the traditional TDOA location method. The feasibility of three methods is verified by numerical simulation and analysis of the positioning error of them. The results show that the comprehensive location method of adding angle difference has strong positioning stability and high positioning accuracy, and it may reduce the impact effectively about ill-conditioned equations to positioning results. Comprehensive location method with the data of actual measure may get better positioning results. 展开更多
关键词 MICROSEISM LOCATION three-dimensional model TDOA POLARIZATION comprehensive location method
下载PDF
Three-dimensional modeling of effect of surface intermetallic phase on surface defects of Al-Fe-Si aluminum foils during twin-roll casting
8
作者 朱远志 万强 +2 位作者 李丙亮 周峰 张雅峰 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第2期477-483,共7页
Scanning electron microscopy and X-ray energy dispersive spectrum analysis show that the clusters of intermetallic AlFeSi particle are distributed on or near the aluminum foil stock surfaces heterogeneously. 3D finite... Scanning electron microscopy and X-ray energy dispersive spectrum analysis show that the clusters of intermetallic AlFeSi particle are distributed on or near the aluminum foil stock surfaces heterogeneously. 3D finite element modeling shows that these clusters of hard particles induce the fracture of the nano-scale lubricant oil film at first and further lead to severe deformation in the nearby aluminum foil substrate along the rolling direction. Consequently, the optical property in this region differs from that in the surroundings, resulting in surface defects. 展开更多
关键词 Al-Fe-Si alloy precipitated phase aluminum foils lubricant oil film twin-roll cast 3D modeling
下载PDF
Numerical Simulation of Saline Intrusion and Purging in Long SeaOutfalls with Three-Dimensional Model 被引量:1
9
作者 吴玮 严忠民 吴龙华 《China Ocean Engineering》 SCIE EI 2006年第2期279-288,共10页
Saline intrusion into marine sewage ouffalls will greatly decrease the efficiency of sewage disposal. In order to investigate the mechanisms of this flow, in this paper, a three-dimensional numerical model based on F... Saline intrusion into marine sewage ouffalls will greatly decrease the efficiency of sewage disposal. In order to investigate the mechanisms of this flow, in this paper, a three-dimensional numerical model based on FVM (Finite Volume Method) is established, The RNG κ-ε model is selected for turbulence modeling. The time-averaged vohtme fraction equations are introduced to simulate the stratification and inteffaeial exchange of sewage and seawater in outfalls. Validity of the established three-dimensional numerical model is evaluated by comparisons of numerical results with experimental data. With this three-dimensional numerical model, the internal flow characteristics in ouffalls for different sewage discharges are simulated. The results indicate that for a low sewage discharge, saline circulates in the outfall due to intrusion and both the inflowing momentum and the inteffaeial turbulent mixing are important mechanisms to extrude the saline. For a high sewage discharge, saline intrusion could be avoided. The inflow momentum is the main mechanism to extrude the saline and the inteffacial turbulent mixing is nut important relatively. Even at a high sewage discharge, the saline wedge would be retained in the main ouffall pipe after the risers are purged. It takes a long time for this saline wedge to be extruded by interracial turbulent mixing. 展开更多
关键词 sea outfalls saline intrusion saline purging three-dimensional numerical model experimental study
下载PDF
Three-Dimensional Model Reconstruction of Nonwovens from Multi-Focus Images 被引量:2
10
作者 DONG Gaige WANG Rongwu +1 位作者 LI Chengzu YOU Xiangyin 《Journal of Donghua University(English Edition)》 CAS 2022年第3期185-192,共8页
The three-dimensional(3D)model is of great significance to analyze the performance of nonwovens.However,the existing modelling methods could not reconstruct the 3D structure of nonwovens at low cost.A new method based... The three-dimensional(3D)model is of great significance to analyze the performance of nonwovens.However,the existing modelling methods could not reconstruct the 3D structure of nonwovens at low cost.A new method based on deep learning was proposed to reconstruct 3D models of nonwovens from multi-focus images.A convolutional neural network was trained to extract clear fibers from sequence images.Image processing algorithms were used to obtain the radius,the central axis,and depth information of fibers from the extraction results.Based on this information,3D models were built in 3D space.Furthermore,self-developed algorithms optimized the central axis and depth of fibers,which made fibers more realistic and continuous.The method with lower cost could reconstruct 3D models of nonwovens conveniently. 展开更多
关键词 three-dimensional(3D)model reconstruction deep learning MICROSCOPY NONWOVEN image processing
下载PDF
Development of a Percentile Based Three-dimensional Model of the Buttocks in Computer System 被引量:2
11
作者 WANG Lijing HE Xueli LI Hongpeng 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2016年第3期633-640,共8页
There are diverse products related to human buttocks, which need to be designed, manufactured and evaluated with 3D buttock model. The 3D buttock model used in present research field is just simple approximate model s... There are diverse products related to human buttocks, which need to be designed, manufactured and evaluated with 3D buttock model. The 3D buttock model used in present research field is just simple approximate model similar to human buttocks. The 3D buttock percentile model is highly desired in the ergonomics design and evaluation for these products. So far, there is no research on the percentile sizing system of human 3D buttock model. So the purpose of this paper is to develop a new method for building three-dimensional buttock percentile model in computer system. After scanning the 3D shape of buttocks, the cloud data of 3D points is imported into the reverse engineering software(Geomagic) for the reconstructing of the buttock surface model. Five characteristic dimensions of the buttock are measured through mark-points after models being imported into engineering software CATIA. A series of space points are obtained by the intersecting of the cutting slices and 3D buttock surface model, and then are ordered based on the sequence number of the horizontal and vertical slices. The 1st, 5th, 50 th, 95 th, 99 th percentile values of the five dimensions and the spatial coordinate values of the space points are obtained, and used to reconstruct percentile buttock models. This research proposes a establishing method of percentile sizing system of buttock 3D model based on the percentile values of the ischial tuberosities diameter, the distances from margin to ischial tuberosity and the space coordinates value of coordinate points, for establishing the Nth percentile 3D buttock model and every special buttock types model. The proposed method also serves as a useful guidance for the other 3D percentile models establishment for other part in human body with characteristic points. 展开更多
关键词 three-dimensional percentile buttock model point-cloud
下载PDF
Three-Dimensional Modelling of a Multi-Layer Sandstone Reservoir: the Sebei Gas Field, China 被引量:6
12
作者 OU Chenghua WANG Xiaolu +1 位作者 LI Chaochun HE Yan 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2016年第1期209-221,共13页
Multi-layer sandstone reservoirs occur globally and are currently in international production. The 3D characteristics of these reservoirs are too complicated to be accurately delineated by general structural-facies-re... Multi-layer sandstone reservoirs occur globally and are currently in international production. The 3D characteristics of these reservoirs are too complicated to be accurately delineated by general structural-facies-reservoir modelling. In view of the special geological features, such as the vertical architecture of sandstone and mudstone interbeds, the lateral stable sedimentation and the strong heterogeneity of reservoir poroperm and fluid distribution, we developed a new three-stage and six-phase procedure for 3D characterization of multi-layer sandstone reservoirs. The procedure comprises two-phase structural modelling, two-phase facies modelling and modelling of two types of reservoir properties. Using this procedure, we established models of the formation structure, sand body structure and microfacies, reservoir facies and properties including porosity, permeability and gas saturation and provided a 3D fine-scale, systematic characterization of the Sebei multi-layer sandstone gas field, China. This new procedure, validated by the Sebei gas field, can be applied to characterize similar multi-layer sandstone reservoirs. 展开更多
关键词 multi-layer sandstone reservoir 3D characterization PROCEDURE Sebei gas field geological model reservoir modelling
下载PDF
Risk Assessment of Coal Mine Water Hazard Based on Three-Dimensional Model of Geology and Underground Space 被引量:1
13
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
下载PDF
Three-dimensional Modeling for Predicting the Vibration Modes of Twin Ball Screw Driving Table 被引量:5
14
作者 WANG Renche ZHAO Tong +1 位作者 YE Peiqing LIU Yan 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2014年第1期211-218,共8页
As a redundant drive mechanism, twin ball screw feed system has the advantage of high stiffness and little yaw vibration in the feeding process, while leads to increased difficulty with vibration characteristics analy... As a redundant drive mechanism, twin ball screw feed system has the advantage of high stiffness and little yaw vibration in the feeding process, while leads to increased difficulty with vibration characteristics analysis and structure optimization. Only low-dimensional structure and dynamics parameters are considered in the existing research, the complete and effective model for predicting the table's vibrations is lacked. A three-dimensional(3D) mechanical model of twin ball screw driving table is proposed. In order to predict the vibration modes of the table quantitatively, an analytical formulation following a comprehensive approach is developed, where the drive system is modeled as a lumped mass-spring system, and the Lagrangian method is used to obtain the table's independent and coupled axial, yaw, and pitch vibration modes. The frequency variation of each mode is studied for different heights of the center of gravity, nut positions and table masses by numerical simulations. Modal experiment is carried out on the Z-axis feed table of the horizontal machining center MCH63. The results show that for each mode, the error between the estimated and the measured frequencies is less than 13%. The independent and coupled vibration modes are in accordance with the experimental results, respectively The proposed work can serve a better understanding of the table's dynamics and be beneficial for optimizing the structure parameters of twin ball screw drive system in the design stage. 展开更多
关键词 twin ball screw drive dynamic modeling vibration mode
下载PDF
Self-consistent three-dimensional modeling and simulation of large-scale rectangular surface-wave plasma source 被引量:3
15
作者 蓝朝晖 蓝朝桢 +2 位作者 胡希伟 陈兆权 刘明海 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第6期2412-2419,共8页
A self-consistent and three-dimensional (3D) model of argon discharge in a large-scale rectangular surface-wave plasma (SWP) source is presented in this paper, which is based on the finite-difference time-domain ... A self-consistent and three-dimensional (3D) model of argon discharge in a large-scale rectangular surface-wave plasma (SWP) source is presented in this paper, which is based on the finite-difference time-domain (FDTD) approximation to Maxwell's equations self-consistently coupled with a fluid model for plasma evolution. The discharge characteristics at an input microwave power of 1200 W and a filling gas pressure of 50 Pa in the SWP source are analyzed. The simulation shows the time evolution of deposited power density at different stages, and the 3D distributions of electron density and temperature in the chamber at steady state. In addition, the results show that there is a peak of plasma density approximately at a vertical distance of 3 cm from the quartz window. 展开更多
关键词 FDTD method surface wave plasma fluid model
下载PDF
A Three-Dimensional Model of Transport and Diffusion of Seeding Agents within Stratus 被引量:7
16
作者 余兴 戴进 +1 位作者 蒋维楣 樊鹏 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2000年第4期617-635,共19页
It is essential to learn the temporal and spatial concentration distributions and variations of seeding agents in cloud seeding of precipitation enhancement. A three-dimensional puff trajectory model incorporating a m... It is essential to learn the temporal and spatial concentration distributions and variations of seeding agents in cloud seeding of precipitation enhancement. A three-dimensional puff trajectory model incorporating a mesoscale nonhydrostatic model has been formulated, and is applied to simulating the transporting and diffusive characteristics of multiple line sources of seeding agents within super-cooled stratus. Several important factors are taken into consideration that affect the diffusion of seeding materials such as effects of topography and vertical wind shear, temporal and spatial variation of seeding parameters and wet deposition. The particles of seeding agents are assumed to be almost inert, they have no interaction with the particles of the cloud or precipitation except that they are washed out by precipitation. The model validity is demonstrated by the analyses and comparisons of model results, and checked by the sensitivity experiments of diffusive coefficients and atmospheric stratification. The advantage of this model includes not only its exact reflection of heterogeneity and unsteadiness of background fields, but also its good simulation of transport and diffusion of multiple line sources. The horizontal diffusion rate and the horizontal transport distance have been proposed that they usually were difficult to obtain in other models. In this simulation the horizontal diffusion rate is 0.82 m s(-1) for average of one hour, and the horizontal average transport distance reaches 65 km after 1 4 which are closely related to the background Fields. 展开更多
关键词 puff trajectory model transport and diffusion multiple line sources of seeding agents heterogeneity and unsteadiness diffusion rate and transport distance super-cooled stratus
下载PDF
Three-dimensional modeling in complex liver surgery and liver transplantation 被引量:3
17
作者 Jian-Peng Liu Jan Lerut +2 位作者 Zhe Yang Ze-Kuan Li Shu-Sen Zheng 《Hepatobiliary & Pancreatic Diseases International》 SCIE CAS CSCD 2022年第4期318-324,共7页
Liver resection and transplantation are the most effective therapies for many hepatobiliary tumors and diseases.However,these surgical procedures are challenging due to the anatomic complexity and many anatomical vari... Liver resection and transplantation are the most effective therapies for many hepatobiliary tumors and diseases.However,these surgical procedures are challenging due to the anatomic complexity and many anatomical variations of the vascular and biliary structures.Three-dimensional(3D)printing models can clearly locate and describe blood vessels,bile ducts and tumors,calculate both liver and residual liver volumes,and finally predict the functional status of the liver after resection surgery.The 3D printing models may be particularly helpful in the preoperative evaluation and surgical planning of especially complex liver resection and transplantation,allowing to possibly increase resectability rates and reduce postoperative complications.With the continuous developments of imaging techniques,such models are expected to become widely applied in clinical practice. 展开更多
关键词 3D printing models Liver surgery Liver transplantation
下载PDF
An Improved Three-Dimensional Model for Emotion Based on Fuzzy Theory
18
作者 Zijiang Zhu Junshan Li +1 位作者 Xiaoguang Deng Yi Hu 《Journal of Computer and Communications》 2018年第8期101-111,共11页
Emotion Model is the basis of facial expression recognition system. The constructed emotional model should not only match facial expressions with emotions, but also reflect the location relationship between different ... Emotion Model is the basis of facial expression recognition system. The constructed emotional model should not only match facial expressions with emotions, but also reflect the location relationship between different emotions. In this way, it is easy to understand the current emotion of an individual through the analysis of the acquired facial expression information. This paper constructs an improved three-dimensional model for emotion based on fuzzy theory, which corresponds to the facial features to emotions based on the basic emotions proposed by Ekman. What’s more, the three-dimensional model for motion is able to divide every emotion into three different groups which can show the positional relationship visually and quantitatively and at the same time determine the degree of emotion based on fuzzy theory. 展开更多
关键词 EMOTION model FACIAL EXPRESSION FUZZY Theory three-dimensional STATE-SPACE
下载PDF
Three-dimensional modelling of shear keys in concrete gravity dams using an advanced grillage method 被引量:1
19
作者 Mahdi Ben Ftima Steephane Lafrance Pierre Leeger 《Water Science and Engineering》 EI CAS CSCD 2020年第3期223-232,共10页
Contraction joint shear keys are resilient features of gravity dams that can be considered to increase the sliding safety factors or minimise seismic residual sliding displacements,allowing costly remedial actions to ... Contraction joint shear keys are resilient features of gravity dams that can be considered to increase the sliding safety factors or minimise seismic residual sliding displacements,allowing costly remedial actions to be avoided.This paper presents a novel,robust,and computationally efficient three-dimensional(3D)modelling and simulation strategy of gravity dams,using a series of adjacent cantilever beam elements to represent individual monoliths.These monoliths are interconnected in the longitudinal direction by 3D no-tension link elements representing the lumped shear key stiffness contributions at a particular elevation.The objective is to assess the shear key internal force demands,including the axial force,shear,and moment demands.Shear key demand-capacity ratios can then be assessed with related multi-axial failure envelopes.The 3D link element stiffness coefficients were derived from a series of 3D finite element(FE)solid models with a detailed representation of geometrical features of multiple shear keys.The results from the proposed method based on advanced grillage analysis show strong agreement with reference solutions from 3D FE solid models,demonstrating high accuracy and performance of the proposed method.The application of the proposed advanced grillage method to a dam model with two monoliths clearly shows the advantage of the proposed method,in comparison to the classical approach used in practise. 展开更多
关键词 Gravity dam Shear keys Seismic analysis Grillage analysis Finite element model Multi-scale approach
下载PDF
The Establishment of Three-Dimensional Model of Human Knee Joint
20
作者 Ziyue Liu Fuzhong Wang 《Journal of Software Engineering and Applications》 2015年第1期1-5,共5页
Objective: To discuss a method to establish a three-dimensional model of healthy human knee joint, which can be used for further knee joint biomechanics analysis and simulation. Methods: CT scan and medical image thre... Objective: To discuss a method to establish a three-dimensional model of healthy human knee joint, which can be used for further knee joint biomechanics analysis and simulation. Methods: CT scan and medical image three-dimensional reconstruction software (Mimics) were used to obtain the knee joint three-dimensional finite element model (FEM) according to reverse engineering theory. Results: FEM of knee joint with complete bone structure was established by Mimics. Conclusion: Three-dimensional FEM was established according to CT images exports as IGES file. The model can be used for knee joint biomechanics finite element analysis to provide references and proposals for the clinical diagnoses of knee joint illness, and the design of artificial knee joint prosthesis. 展开更多
关键词 KNEE JOINT MIMICS three-dimensional model
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部