排序方式: 共有36条查询结果,搜索用时 187 毫秒
11.
An oil dielectric helical pulse line to demonstrate the principles of a Pulse Line Ion Accelerator (PLIA) has been designed and fabricated. The simulation of the axial electric field of an accelerator with CST code has been completed and the simulation results show complete agreement with the theoretical calculations. To fully understand the real value of the electric field excited from the helical line in PLIA, an optical electric integrated electric field measurement system was adopted. The measurement result shows that the real magnitude of axial electric field is smaller than that calculated, probably due to the actual pitch of the resister column which is much less than that of helix. 相似文献
12.
Two types of dielectric wall accelerator (DWA) structures, a bi-polar Blumlein line and zero integral pulse line (ZIP) structures were investigated. The high gradient insulator simulated by the particle in cell code con rms that it has little in uence on the axial electric field. The results of simulations using CST microwave studio indicate how the axial electric field is formed, and the electric eld waveforms agree with the theoretical one very well. The in uence of layer-to-layer coupling in a ZIP structure is much smaller and the electric eld waveform is much better. The axial of the Blumlein structure's electric field has better axial stability. From both of the above, it found that for a shorter pulse width, the axial electric field is much higher and the pulse stability and delity are much better. The CST simulation is very helpful for designing DWA structures. 相似文献
13.
基于EGS5与PARMELA模拟软件组成的高能电子成像系统,对暗场成像的模拟研究发现,通过调节光阑位置实现的暗场成像结果存在失真现象。针对该失真现象提出的改进方案,消除了暗场成像结果的失真。通过对40 MeV电子透射7~224 μm的铝样品开展的成像模拟结果表明:40 MeV高能电子暗场成像技术在铝样品厚度小于25 μm情况下具有明显的面密度分辨优势,且空间分辨率达到μm量级,非常适用于高能量密度物质诊断。 相似文献
14.
Ultrafast imaging tools are of great importance for determining the dynamic density distribution in high energy density(HED) matter. In this work, we designed a high energy electron radiography(HEER) system based on a linear electron accelerator to evaluate its capability for imaging HED matter. 40 MeV electron beams were used to image an aluminum target to study the density resolution and spatial resolution of HEER. The results demonstrate a spatial resolution of tens of micrometers. The interaction of the beams with the target and the beam transport of the transmitted electrons are further simulated with EGS5 and PARMELA codes, with the results showing good agreement with the experimental resolution.Furthermore, the experiment can be improved by adding an aperture at the Fourier plane. 相似文献
15.
16.
考虑视轴方向的个性化眼模型的构建 总被引:1,自引:0,他引:1
包含更多人眼解剖学特性的个性化眼模型具有重要的实验和临床意义。由角膜地形图计算了8只人眼视轴与光轴之间的夹角,水平分量平均值为4.23°±1.51°,竖直分量平均值为-0.40°±1.27°。根据视轴与光轴之间的夹角、角膜地形数据、眼内各部分轴向间距和人眼波像差,运用光学设计软件Zemax分别为这8只人眼构建了考虑视轴方向的个性化眼模型。在此基础上,计算了波前引导的个性化角膜切削深度,并与光程差方法计算的切削深度进行了比较。在切削光区中心处,两者相差不大,平均值为(0.09±0.04)μm;随着半径增大,两者之间的差值逐渐增大。对于所研究的实例,光区外围处的最大差值为0.59μm。个性化眼模型为设计波前引导的个性化角膜切削方案提供了一个有效工具。 相似文献
17.
基于个性化人眼模型的大视场波像差特性的研究 总被引:4,自引:1,他引:3
大视场波前像差对人眼光学系统的影响不容忽视。运用Zemax光学设计软件分别为8只正常人眼构建了个性化的人眼模型,该人眼模型由实际测量的人眼波前像差数据、角膜地形数据及眼内各部分轴向间距数据优化得来,与个体人眼具有相同的光学特性。在此基础上,分析了人眼颞侧方向0°,10°,20°,30°,40°,50°视场的离轴像差随视场角的变化趋势,得出边缘视觉比中央视觉质量差主要来源在于像散与彗差。四阶以上的高阶像差随着视场角的改变,变化不大。将个性化人眼模型计算得到的大视场波前像差值与用哈特曼夏克(Hartmann-Shack)波前传感器实际测量得到的人眼像差值相比较,两者结果相吻合。 相似文献
18.
19.
We present a global optimization method, called the genetic algorithms (GAs), for digital image/speckle correlation (DISC). The new algorithms do not involve reasonable initial guess of displacement and deformation gradient and the calculation of second-order spatial derivatives of the digital images, which are important challenges in practical implementation of DISC. The performance of a GA depends largely on the selection of the genetic operators. We test various operators and propose optimal operators. The algorithms are then verified using simulated images and experimental speckle images. 相似文献
20.
In order to put the Pulse Line Ion Accelerator (PLIA) concept to its practical application, a small experimental platform was built. It was found that the actual axial electric field is smaller than the theoretical calculation, so the accelerated ions will enter into the deceleration zone before leaving the helix, which will seriously affect the acceleration process. Based on the improved parameters, the He+ with 24 keV is accelerated to 55 keV, and the proof-of-principle experiment is completed on this platform. 相似文献