【摘 要】
：
基于同步辐射X射线的优越特性及计算机断层重建技术对材料无损检测等优点,同步辐射计算机断层重建技术被广泛应用于很多领域.本文对光源非均匀、过饱和以及过穿透的三种情形所引起同步辐射计算机断层技术重建误差的形成机理进行了分析研究,给出了三种情形所引起误差的基本形式.在此基础上,对这三种误差进行了数值模拟,模拟结果证实了分析的正确性.
论文部分内容阅读
基于同步辐射X射线的优越特性及计算机断层重建技术对材料无损检测等优点,同步辐射计算机断层重建技术被广泛应用于很多领域.本文对光源非均匀、过饱和以及过穿透的三种情形所引起同步辐射计算机断层技术重建误差的形成机理进行了分析研究,给出了三种情形所引起误差的基本形式.在此基础上,对这三种误差进行了数值模拟,模拟结果证实了分析的正确性.
其他文献
Water distribution and gas supply systems are among the infrastructure systems that have many buried steel pipelines. Corrosion gradually appears inside and outside of the pipe walls over the service
By the end of 2006,China had launched 24 recoverable satellites(FSW)in total.Among them,23 were launched successfully,of which all but one were successfully recovered.Recoverable satellites launched b
Saturated hydraulic conductivity (Ks) is an important soil hydraulic parameter for charactering the rate of water flow across the soils and is mainly related to its high spatial variability. In a smal
虽然目前边界分离噪声检测(BDND)算法被普遍认为是一种较好的去除图像脉冲噪声方法,然而研究发现当"盐"或"胡椒"噪声污染比例之一超过50%,其性能却急剧下降,几乎无法去噪.为此在BDND算法基础上提出了改进的噪声检测方法(Mod ified BDND),对每个子图,新方法选取与"128"最接近的灰度值作为分界点,从而避免原方法因选取中值为分界点而可能落入污染区域的问题.该方法既可保留BDND算法
信息多视图分析与设计是文献信息个性化服务技术中的核心内容之一。采用模型-视图-控制体系结构的编程技术体现了数据维护与数据呈现分离的思想,这种结构既可以用于一个完整的可视化应用程序的设计,也可以用于一个具体的可视化组件的对象中。本文从完整的可执行程序和可视化组件对象两个角度,讨论MVC结构各部分的作用及其相互关系,并通过信息多视图设计实例说明这种体系结构在信息可视化分析与设计中的应用。
Radio frequency identification (RFID) technology has proved to be very effective in industries as diverse as aircraft manufacturing to health and care. The construction industry has been slow to take
The purpose of this research is to propose an early restoration for lifeline systems after earthquake disasters. The previous researches show that the optimization of the restoration schedule by using
The theory of moving frames developed by Peter J Olver and M Fels has impor-tant applications to geometry, classical invariant theory. We will use this theory to classify joint invariants and joint di
Wheeler pointed out that the period of Matthews cha-otic function (MCF) is often too short to be suitable for crypto-graphic usage in the manner of computer statistics,but this state-ment was given on