抛物面的

When the pinhole is at a distance of 200 m, the spherical aberration of a perfect paraboloid will be reduced to about 0.027 mm, equivalent to a 1/10 wavefront error.

当此针孔距离是 200 公尺时对壹个完美抛物面的球面像差将被减小至0.027mm，相等于 1/10 波前误差。

The results show that the vehicle acceleration, the dynamic wheel load and offload factors increase with train speed, and distribute linearly. The safety of train operation and running comfort can meet the requirements when the high-speed train under secondary suspension passing through ballasted track subgrade structure. The dynamic displacement of the system is less influenced by train speed. The dynamic stress of subgrade surface increases with speed improving, and it is distributed as saddle along the lateral direction and as parabola along the longitudinal direction of subgrade surface. The dynamic stress of subgrade declines sharply along the depth of subgrade. The dynamic stress on 3 m depth below subgrade bed surface is about 16 percent of that of subgrade surface.

结果表明：车体加速度、动轮载和轮重减载率均随车速的提高而增大，呈线性分布；具有二系悬挂的高速列车通过有砟轨道路基结构时，列车的安全性及舒适度均能满足要求；系统动位移受速度影响较小；路基面动应力随速度的提高而增大，并在横向呈马鞍形分布，在纵向呈抛物线形分布；路基动应力沿路基深度方向衰减较快，在基床表面下3 m处，动应力只有基面的16%左右。

I presented some diagrams of efficiency of a coffee can with different diameters as feeds for parabolas with different F/D and it is very clear how efficiently they work with offset dishes whose F/D is in the range 0.7-0.9.

我提供一些不同直径的咖啡罐做不同F/D的抛物面的馈源的效率图表，可以清楚的看出，当偏馈抛物面天线的F/D在0.7-0.9范围时，它们的工作效率如何。

Singer Leona Lewis and former Led Zeppelin guitarist Jimmy Page emerged as the bus transformed into a grass-covered carnival float, and the pair combined for a rendition of "Whole Lotta Love".

歌手leona刘易斯和前率领的飞艇的吉他手吉米页出现巴士转化为基层所涵盖的嘉年华花车，和一双合并为一移交&整个lotta爱&。

This is Kate, and that's Erin.

这是凯特，那个是爱朗。