折射

In such a medium, the direction of the Poynting vector monochromatic plane wave is antiparallel to that of its phase velocity. Because of that, DNG displays some unusual electromagnetic properties such as backward-wave effect, negative refractive effect, perfect lens and a limit situation, zero index of refraction materials.

在这种材料中，单色均匀平面波的相速方向和坡印亭矢量方向是相反的，因此使双负材料表现出一系列反常的电磁特性如：回波效应、负折射效应、完美透镜效应和一种极限情况即零折射率材料等。

So the Poynting vector and wave vector are antiparallel, consequently, the light is refracted negatively, and also there are many other unusual behaviors in LHM like reverse Cerenkov radiation, contrary Doppler effect etc.

所以近年来有关左手材料的研究受到了广泛的关注。2002年，科学家们发现当光波以一定角度入射到在光子晶体界面上时，光波在光子晶体中的传输也会出现和在左手材料中相同的现象：比如负折射和超透镜现象。

By 1933 Zeiss had manufactured several proven refractors of the "E","A" and "AS" achromatic doublet designs, and apochromat triplets of the "U.V."

1933年，蔡司生产了"E"，"A"和"AS"等几款使用消色差镜头设计，并经过实际使用验证的折射望远镜，还有"U.V。"

This was also the year they introduced the prototype FCT-150 fluorite triplet apochromat and the revolutionary EM-2000 mount which used electric clutches and had a direct read out of R.A. and Dec.

这一年也是FCT-150萤石三片式APO折射镜和革命性的EM-2000型赤道仪问世的时间，EM-2000使用电子装置可以直接读出赤经/赤纬度。

For example, a small low-cost wide-field refractor like the 80mm f/5 "short tube" achromats cannot easily compete with the performance of an expensive 3 element Apochromat, nor should it be expected to. These inexpensive scopes don't generally perform as well at higher powers, but they were never designed to do so.

比如像80F5这种小的低成本宽视场折射镜和与价格昂贵的三片APO根本没法比，虽然这些廉价的镜子高倍表现不好，但是它的设计本来也不是为了上高倍。

These are the largest fluorite apochromatic refractors available in the world.

这是世界上最大的APO折射镜了。

The new Maxivision 5 inch apochromatic triplet telescope just performs so good than I cannot belief my eyes.

此新的"大有可观" 5 英吋口径复消色差折射镜的表现是这么好我不能相信我的眼睛。

You'll also need a diagonal and if this is your first apochromatic refractor, I'll recommend a 3-6 nagler zoom.

如果这是你的第一架复消色差折射望远镜，那么你还需要一个天顶镜。我推荐用3－6毫米耐格勒变焦的天顶镜。

Homas back is already regarded as the top performer in triplet apochromatic refractor.

MB 已被认为是最佳表现的三片镜片复消色差折射镜。

This was the apochromatic refractor.

这就是APO折射式望远镜。

I can not make it blossom and suits me

我不能让树为我开花

When temperatures are above approximately 80 °C discolouration of the raceways or rolling elements is a frequent feature.

当温度高于 80 °C 左右时，滚道或滚动元件褪色是很常见的特征。