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一种新的三维CT扫描系统投影坐标原点的高精度测量方法 被引量:2
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作者 杨民 孙晶晶 +1 位作者 王钢 吴文晋 《上海交通大学学报》 EI CAS CSCD 北大核心 2008年第4期590-593,598,共5页
针对实际的三维CT扫描成像系统射线源焦点和探测器成像面的位置不能直接测量的问题,提出了一种简单易行的投影坐标系原点位置精确测量方法.利用双圆目标体二次成像获得的DR(Digital Radiography)图像,配合图像、图形处理方法和最小二乘... 针对实际的三维CT扫描成像系统射线源焦点和探测器成像面的位置不能直接测量的问题,提出了一种简单易行的投影坐标系原点位置精确测量方法.利用双圆目标体二次成像获得的DR(Digital Radiography)图像,配合图像、图形处理方法和最小二乘拟合技术求取不同成像位置下的目标体圆心投影坐标,然后求解方程组得到投影坐标系的原点坐标.实验结果表明,所提出方法的测量精度达到了实际扫描系统的重建要求,并且实现简单、具有较强的抗噪能力. 展开更多
关键词 三维计算机断层扫描 投影坐标原点 最小二乘拟合 射线检测
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Numerical simulation of asphalt mixture based on three-dimensional heterogeneous specimen 被引量:5
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作者 张肖宁 万成 +1 位作者 王栋 贺玲凤 《Journal of Central South University》 SCIE EI CAS 2011年第6期2201-2206,共6页
In order to verify the validity of finite element numerical simulation method for asphalt mixture, which consists of aggregates, mastic (where mastic is a kind of fine mixture composed of asphalt binder mixed with fi... In order to verify the validity of finite element numerical simulation method for asphalt mixture, which consists of aggregates, mastic (where mastic is a kind of fine mixture composed of asphalt binder mixed with fines and fine aggregates) and air voids, based on three-dimensional (3D) heterogeneous specimen, X-ray computerized tomography (X-ray CT) was used to scan the asphalt specimens to obtain the real internal microstrnctures of asphalt mixture. CT images were reconstructed to build up 3D digital specimen, and the viscoelastic properties of mastic were described with Burgers model The uniaxial creep numerical simulations of three different levels of aggregate gradation were conducted. The simulation results agree well with the experimental results. The numerical simulation of asphalt mixture incorporated with real 3D microstructure based on finite element method is a promising application to conduct research of asphalt concrete. Additionally, this method can increase the mechanistic understanding of global viscoelastic properties of asphalt mixtures by linking the real 3D microstructure. 展开更多
关键词 asphalt mixture X-ray CT 3D heterogeneous specimen numerical simulation
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