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血管横截面参数模型及其在血管重建中的应用
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作者 王勇 牟轩沁 +1 位作者 俞恒永 蔡元龙 《西安交通大学学报》 EI CAS CSCD 北大核心 2002年第6期635-638,共4页
为了改善传统重建方法在稀疏投影等病态情形下的重建效果 ,分析了描述血管弹性性质的微分方程 ,并利用离散余弦变换的能量压缩特性 ,建立了具有圆形分量、椭圆分量等 10个参数的截面模型 .与圆形、椭圆形截面模型相比 ,该模型能够更逼... 为了改善传统重建方法在稀疏投影等病态情形下的重建效果 ,分析了描述血管弹性性质的微分方程 ,并利用离散余弦变换的能量压缩特性 ,建立了具有圆形分量、椭圆分量等 10个参数的截面模型 .与圆形、椭圆形截面模型相比 ,该模型能够更逼真地描述血管横截面 .利用该模型还可以对传统重建方法进行后处理 ,从而改善重建效果 .仿真结果表明 :该模型描述各种血管横截面的误差仅为 2 0 4 % ,在病态投影的情况下可以使重建误差减小到 5 %左右 . 展开更多
关键词 参数模型 三维重建 傅里叶描述器 血管横截面边界
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确定任意多边形区域截面核心的算法
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作者 陈载思 《江西科学》 2002年第3期159-162,共4页
根据任意多边形区域边界线上的节点坐标 ,给出一种比较简单的截面边界的凸凹判别准则 ,由此可以将任意复杂的多边形区域自动划分为有限个三角形子区域 ,然后根据几何量计算的叠加性和对三角形子区域的精确解 ,确定任意复杂多边形截面在... 根据任意多边形区域边界线上的节点坐标 ,给出一种比较简单的截面边界的凸凹判别准则 ,由此可以将任意复杂的多边形区域自动划分为有限个三角形子区域 ,然后根据几何量计算的叠加性和对三角形子区域的精确解 ,确定任意复杂多边形截面在任意参考坐标系下的截面几何特性 。 展开更多
关键词 任意多边形区域 截面核心 凸凹性判别准则 截面边界 平面几何 计算机求解算法 三角形子区域叠加
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Scattering wave field around a cavity with circular cross-section embedded in saturated soil using boundary element method 被引量:3
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作者 张鸿 高谦 徐斌 《Journal of Central South University》 SCIE EI CAS 2013年第11期3296-3304,共9页
Based on Biot’s theory and considering the properties of a cavity,the boundary integral equations for the numerical simulation of wave scattering around a cavity with a circular cross-section embedded in saturated so... Based on Biot’s theory and considering the properties of a cavity,the boundary integral equations for the numerical simulation of wave scattering around a cavity with a circular cross-section embedded in saturated soil are obtained using integral transform methods.The Cauchy type singularity of the boundary integral equation is discussed.The effectiveness of the properties of soil mass and incident field on the dynamic stress concentration and pore pressure concentration around a cavity is analyzed.Our results are in good agreement with the existing solution.The numerical results of this work show that the dynamic stress concentration and pore pressure concentration are influenced by the degree of fluid–solid coupling as well as the pore compressibility and water permeability of saturated soil.With increased degree of fluid–solid coupling,the dynamic stress concentration improves from 1.87 to 3.42 and the scattering becomes more significant.With decreased index of soil mass compressibility,the dynamic stress concentration increases and its maximum reaches 3.67.The dynamic stress concentration increases from 1.64 to 3.49 and pore pressure concentration improves from 0.18 to 0.46 with decreased water permeability of saturated soil. 展开更多
关键词 saturated soil boundary integral equations wave scattering dynamic stress concentration Green's function
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The effects of slip condition and fluid flow through a channel multiple stenoses on micropolar of non-uniform cross-section
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作者 K. Vaj ravelu Gurju Awgichew G. Radhakrishnamacharya 《International Journal of Biomathematics》 2015年第4期237-255,共19页
In this paper, steady incompressible micropolar fluid flow through a non-uniform channel with multiple stenoses is considered. Assuming the stenoses to be mild and using the slip boundary condition, the equations gove... In this paper, steady incompressible micropolar fluid flow through a non-uniform channel with multiple stenoses is considered. Assuming the stenoses to be mild and using the slip boundary condition, the equations governing the flow of the proposed model are solved, and closed-form expressions for the flow characteristics (resistance to flow and wall shear stress) are derived. The effects of different parameters on these flow characteristics are analyzed. It is observed that both the resistance to the flow and the wall shear stress increase with the heights of the stenoses and the slip parameter; but decrease with the Darcy number, b^rthermore, the effects of the wall exponent parameter, the cross-viscosity coefficient and the micropolar parameter on the flow characteristics are discussed. 展开更多
关键词 Stenoses slip condition non-uniform channel flow resistance micropolarfluid.
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