焦距

Aimed at the needs of divagation in virtual environment, we define the position chain, time chain, zooming chain and virtulized chain. Also, a divagation strategy is proposed for vitural panorama space containing position relationship, time relationship, zooming relationship and virtualized relationship.

针对基于图像的虚拟全景空间漫游的需要，在定义位置链、时间链、焦距链和虚化链等链表结构的基础上，提出了一种包含位置关联、时间关联、焦距关联和虚化关联的大规模虚拟全景空间漫游策略。

To meet the needs of detection of space faint objects for a telescope with large aperture and short focal,a binding drawtube telescope scheme to detect space object is presented to overcome the shortcomings that focal length grows and field of view shrinks with the increasing of aperture size in traditional telescope for space detection.The software methods are used to stack collected images to restrain background random noises and to improve image Signal to Noise Ratio and the detecting ability of the whole system.

为了满足空间暗弱目标探测对大口径、短焦距望远镜系统的要求，克服普通望远镜随着口径的增加焦距变长、视场变小的不足，提出了将多镜筒捆绑在一起对同一空域进行观测，通过软件的方式对采集的图像进行叠加来抑制背景随机噪声、提高图像的信噪比和系统的整体探测能力的设想。

This paper calculates the magnetic field distribution of short coil, The electronic in magnetic field movement under the near axis condition is discussed.

本文计算了短线圈内的磁场分布，讨论了近轴条件下电子在磁场中的运动，根据光学焦距的定义，推导出了磁透镜的焦距公式。

Figure 4 illustrates the relationship between the focal length of the lens, field of view, sensor size, and working distance.

一个镜头的基础定义是其焦距，图4图示出镜头焦距，视野，感应器大小，和工作距离间之关系。

They have a focal length, and where an image is formed depends on a combination of the focal length and the distance between the object and the lens.

透镜有焦距，而影像形成的位置，取决于焦距及物体与透镜距离的组合。

The thermal focal distances of grooved rod is measured. Compare with the results of ordinary rods, the result showes that the thermal focal distance has increased 12.9%.

对热焦距进行了测量，与普通的棒的实验结果进行了对比，螺纹棒比普通棒的热焦距大12.9%。

According to the relation spectrum resolution is inverse proportional to focal distance given a certain incident wavelength and phase number,and the theoretic formula is consistent with reported experimental result.

光谱分辨率是评价衍射微透镜分光特性的主要指标，根据标量衍射理论，给出了多台阶位相型菲涅尔透镜的设计公式，并利用球面波的传输理论推导了微透镜主焦距与光谱分辨率之间的函数关系，得出在入射波长和位相台阶数一定的情况下，光谱分辨率与中心焦距之间呈反比；理论推导的结果与已发表的实验结果一致。

When the reflected light returned from the original way and disturbed the incident ray, the reflectivity could not be tested easily and it was solved by using the method of double-ray testing.

结果表明，该镜头的猫眼效应绝对反射率最高可达35.87%，并且与焦距正比，与F数和入射角成反比；近场时的几何发散角与焦距和F数成反比。

The formula group for the design of multi-phase micro Fresnel lens according to scalar diffraction theory was given and the transmission theory of spherical wave were used to deduce the relation of focal distance of the micro lens with spectrum resolution. According to the relation spectrum resolution is inverse proportional to focal distance given a certain incident wavelength and phase number, and the theoretic formula is consistent with reported experimental result.

光谱分辨率是评价衍射微透镜分光特性的主要指标，根据标量衍射理论，给出了多台阶位相型菲涅尔透镜的设计公式，并利用球面波的传输理论推导了微透镜主焦距与光谱分辨率之间的函数关系，得出在入射波长和位相台阶数一定的情况下，光谱分辨率与中心焦距之间呈反比；理论推导的结果与已发表的实验结果一致。

It can be found that can reduce waist the though increasing the distance of input beam to lens or reducing the focal of lens; for the space coupling of pumped solid-state laser, the short focal lens are excelled long focal lens.

对于空间耦合泵浦固体激光器的光纤耦合LD的输出光束，使用短焦距的透镜要优于使用长焦距的透镜。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。