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A new method of mesh simplification for 3-Dimension terrain using Laplace operator 被引量:1
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作者 Zuo Wenpin Che Xiangjiu 《Computer Aided Drafting,Design and Manufacturing》 2012年第1期44-48,共5页
This paper proposes a new method to simplify mesh in 3D terrain. The 3D terrain is presented by digital elevation model. First, Laplace operator is introduced to calculate sharp degree of mesh point, which indicates t... This paper proposes a new method to simplify mesh in 3D terrain. The 3D terrain is presented by digital elevation model. First, Laplace operator is introduced to calculate sharp degree of mesh point, which indicates the variation trend of the terrain. Through setting a critical value of sharp degree, feature points are selected. Second, critical mesh points are extracted by an recursive process, and constitute the simplified mesh. Third, the algorithm of linear-square interpolation is employed to restore the characteris- tics of the terrain. Last, the terrain is rendered with color and texture. The experimental results demonstrate that this method can compress data by 16% and the error is lower than 10%. 展开更多
关键词 3-dimension terrain critical mesh point simplified mesh Laplace operator
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NUMERICAL MODELLING OF THREE-DIMENSION CHARACTERISTICS OF WIND-DRIVEN CURRENT IN THE BOHAI SEA 被引量:5
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作者 赵进平 侍茂崇 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 1993年第1期70-79,共10页
Three- dimension (3-D) wind-driven currents in the Bohai Sea in both winter and summer are calculated by using a 3- D barotropic steady model, and the results are consistent with observed flow char -acteristics. Based... Three- dimension (3-D) wind-driven currents in the Bohai Sea in both winter and summer are calculated by using a 3- D barotropic steady model, and the results are consistent with observed flow char -acteristics. Based on the results, 3- D characteristics of flow, currents at different depths, compensated flow in the lower layer , long and narrow alongshore current, the area of upwelling and downwelling, main circulation in vertical profile, and the current in Bohai Strait are discussed. 展开更多
关键词 the Bohai Sea- 3-dimension model NUMERICAL study WIND-DRIVEN CURRENT
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3-dimensional slope stability analyses using non-associative stress-strain relationships 被引量:4
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作者 CHEN ZuYu SUN Ping +1 位作者 WANG YuJie ZHANG HongTao 《Science China(Technological Sciences)》 SCIE EI CAS 2009年第9期2517-2527,共11页
The research work presented in this paper refers to a new slope stability analysis method used for landslide risk evaluations. It is an extension of the 3-dimensional upper-bound slope stability analysis method propos... The research work presented in this paper refers to a new slope stability analysis method used for landslide risk evaluations. It is an extension of the 3-dimensional upper-bound slope stability analysis method proposed by Chen et al. in 2001,which employs the Mohr-Coulomb's associative flow rule. It has been found that in a 3-dimensional area,a prism may not be able to move at friction angles to all its surrounding interfaces,as required by this associative rule,and convergence problems may occasionally arise. The new method establishes two velocity fields:(i) The plastic one that represents a non-associative and the best representative dilation behavior,and (ii) the virtual one that permits the solution for factor of safety in the work and energy balance equation. The new method can then allow any input value of dilation angle and thus solve the convergence problem. A practical application to a concrete dam foundation is illustrated. 展开更多
关键词 non-associative flow RULE SLOPE stability limit analysis 3-dimension
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立体心电向量图对心肌梗死病变血管定位的价值 被引量:9
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作者 崔超英 杨鹏 +2 位作者 范书英 杜英 王勇 《中国心血管杂志》 2011年第2期109-111,共3页
目的对比分析常规心电图(ECG)和立体心电向量图(3D-VCG),评价3D-VCG在心肌梗死相关动脉(IRA)定位上的应用价值。方法 114例临床确诊心肌梗死患者,经冠状动脉造影,将冠状动脉单支完全闭塞或狭窄≥75%者,分成左前降支(LAD)、左回旋支(LCX... 目的对比分析常规心电图(ECG)和立体心电向量图(3D-VCG),评价3D-VCG在心肌梗死相关动脉(IRA)定位上的应用价值。方法 114例临床确诊心肌梗死患者,经冠状动脉造影,将冠状动脉单支完全闭塞或狭窄≥75%者,分成左前降支(LAD)、左回旋支(LCX)、右冠状动脉(RCA)共3个IRA组,分别分析其ECG和3D-VCG的分区定位特点。结果以3D-VCG心肌梗死诊断标准之前壁区定位LAD,高侧壁定位LCX,下壁定位RCA,阳性检出率高于常规ECG(分别为:91.7%比50%,75%比12.5%,70%比3.5%,均为P<0.01)。阴性检出率:LAD、LCX和RCA组3D-VCG显著低于ECG(2.7%比33.3%,2.1%比50%,0比30%,均为P<0.01)。结论 3D-VCG对心肌梗死IRA有定位诊断价值,且较常规ECG为优。 展开更多
关键词 心肌梗死 心电描记术 立体心电向量图
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心肌梗死患者T波峰-末间期等复极参数的立体心电向量评价 被引量:3
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作者 崔超英 范书英 +2 位作者 李宪伦 杜英 王勇 《中国医药导报》 CAS 2012年第17期80-81,84,共3页
目的应用立体心电向量(3D-VCG)技术,对正常人和心肌梗死患者的T波峰-末间期(Tp-Te)及其他复极参数进行对比研究。方法采用3D-VCG技术,分别测量109例心肌梗死和116例正常人的Tp-Te、T环总时间和T环最大振幅参数,比较组间差异性。结果心... 目的应用立体心电向量(3D-VCG)技术,对正常人和心肌梗死患者的T波峰-末间期(Tp-Te)及其他复极参数进行对比研究。方法采用3D-VCG技术,分别测量109例心肌梗死和116例正常人的Tp-Te、T环总时间和T环最大振幅参数,比较组间差异性。结果心肌梗死组Tp-Te较正常组显著延长[(114.26±27.54)ms vs(100.40±13.61)ms,P<0.05)],T环总时间两组差异不大[(238.70±40.20)ms vs(241.00±38.25)ms,P>0.05],而心肌梗死组T环最大振幅显著减小[(0.39±0.17)mV vs(0.64±0.23)mV,P<0.001]。结论 3D-VCG显示心肌梗死患者复极参数异常,Tp-Te延长提示其跨室壁复极离散度增加。 展开更多
关键词 T波峰-末间期 立体心电向量 心肌梗死 心室复极
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THE DIVERGENCE-CONVERGENCE EFFECT OF SURFACE CURRENT AND ITS ACTION ON THE BOHAI SEA
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作者 赵进平 侍茂崇 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 1993年第2期135-142,共8页
The action of the wind field and the influence of topography can cause divergence or convergence of surface current. The existence of the divergence-convergence effect is proved and the dynamical significance of the d... The action of the wind field and the influence of topography can cause divergence or convergence of surface current. The existence of the divergence-convergence effect is proved and the dynamical significance of the divergent or convergent state and its link with many marine phenomena are pointed out. Divergence fields of surface current in the Bohai Sea in winter and summer are obtained by numerical modelling describing the divergence-convergence character of seasonally wind-driven current. The relation between the effect and seasonal marine phenomena is discussed. Study on the divergence-convergence effect of surface current (DCESC)can be an indirect method for testing the calculated results. 展开更多
关键词 DIVERGENCE divergence-convergence effect SURFACE CURRENT the Bohai SEA 3-dimension model
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Controlling Unstable Discrete Chaos and Hyperchaos Systems
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作者 Xin Li Suping Qian 《Applied Mathematics》 2013年第11期1-6,共6页
A method is introduced to stabilize unstable discrete systems, which does not require any adjustable control parameters of the system. 2-dimension discrete Fold system and 3-dimension discrete hyperchaotic system are ... A method is introduced to stabilize unstable discrete systems, which does not require any adjustable control parameters of the system. 2-dimension discrete Fold system and 3-dimension discrete hyperchaotic system are stabilized to fixed points respectively. Numerical simulations are then provided to show the effectiveness and feasibility of the proposed chaos and hyperchaos controlling scheme. 展开更多
关键词 2-dimension DISCRETE FOLD SYSTEM 3-dimension DISCRETE HYPERCHAOTIC SYSTEM LYAPUNOV Stability Theory Controlling Chaos
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Discussion on design for alkaline cleaning system of continual annealing line
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作者 HE Daohong,YI Fan and LU Zhiyi Baosteel Engineering & Technology Group Co.,Ltd.,Shanghai 201900 《Baosteel Technical Research》 CAS 2010年第S1期117-,共1页
Conventional process flow and main work mechanism of alkaline cleaning process of Continual Annealing Line are generally reviewed in the paper,and the work flow of design is analysed including the lye,rinse water circ... Conventional process flow and main work mechanism of alkaline cleaning process of Continual Annealing Line are generally reviewed in the paper,and the work flow of design is analysed including the lye,rinse water circuit,conductivity detection circuit,utility media supply circuit and other main working circuits.Meanwhile,the heat demand of the alkaline cleaning system,rinse water system and dryer device are also analysed.Lumped parameter method in the heat-transfer theory is adopted to calculate the heating time of unsteady heat transfer for strips in the on-line tank.And the reasons why brush roller is of inverse brush and rinsing nozzles are equipped at the inlet side are found.Types and working principles of iron removal and degreasing devices for alkaline cleaning system,which adopt new magnetic filtration and ultra filtration processes,are described.Besides,the bypass filtering method is used to calculate the processing capacity of magnetic filtration and ultra filtration devices.Finally,the related features of 3-Dimension software "PlantSpace" for designing a CAL in Baosteel are totally introduced,such as specification for piping,co-designing,pipe code and 3-Dimension design process. 展开更多
关键词 alkaline cleaning heating time magnetic filtration ultra filtration 3-dimension design
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A Study of Transform Encoding Using Frequency Spectrum Selection in 3D-DCT for Sequence Image 被引量:1
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作者 WANGShi-gang CHENHe-xin 《The Journal of China Universities of Posts and Telecommunications》 EI CSCD 2001年第3期34-38,共5页
This paper puts forward the concept of laminar e ncoding based on frequency spectrum selection in 3D-DCT of sequence image. And the pattern of laminar encoding is suitable for the demands of the development of current... This paper puts forward the concept of laminar e ncoding based on frequency spectrum selection in 3D-DCT of sequence image. And the pattern of laminar encoding is suitable for the demands of the development of current communication. So this method is very useful in video communication and has wide prospect. 展开更多
关键词 image encode 3-dimensioned Discrete Cosine Transform (3D-DCT) transform encoding frequency spectrum selection
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立体心电向量图对左心室肥厚的诊断价值
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作者 崔超英 柯元南 王云 《临床心电学杂志》 2009年第5期351-353,共3页
目的以二维超声心动图(UCG)作为诊断依据,与常规心电图(ECG)比较,评价立体心电向量图对左心室肥厚(LVH)的诊断价值。方法以二维超声心动图作为左心室肥厚的诊断标准,并测算出左心室重量指数(LVMI)。以男性左心室重量指数(LVMI)≥97g/m2... 目的以二维超声心动图(UCG)作为诊断依据,与常规心电图(ECG)比较,评价立体心电向量图对左心室肥厚(LVH)的诊断价值。方法以二维超声心动图作为左心室肥厚的诊断标准,并测算出左心室重量指数(LVMI)。以男性左心室重量指数(LVMI)≥97g/m2、女性左心室重量指数(LVMI)≥86g/m2为标准,分为左心室肥厚组及正常对照组;两组同时行心电图和立体心电向量图检查,常规心电图左心室肥厚的诊断标准采用修改的纽约心脏病学会(NYHAC)标准,分别计算立体心电向量图和常规心电图诊断左心室肥厚的敏感性、特异性、阳性正确率、阴性正确率、诊断准确率。两组间的比较用x2检验。结果LVH组3D-VCG的典型表现是额面(F)QRS环最大向量振幅和水平面(F)QRS环最大向量振幅明显增大,且QRS环空间最大向量偏向左后。立体心电向量图诊断左心室肥厚的特异性和阳性正确率与心电图无显著差异(p>0.05);但敏感性显著高于心电图(p=0.0001),阴性正确率、诊断准确率亦均显著高于心电图(p=0.005)。结论由于立体心电向量图较常规心电图能获得更全面的信息,在左心室肥厚诊断方面,立体心电向量图的诊断价值高于常规心电图。 展开更多
关键词 心电向量图 立体心电向量图 超声心动图
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