It is demonstrated that ML estimating error can converge to CRB quickly with increasing synthetic aperture length and Signal to Noise Ratio (SNR), but a threshold effect exists.
研究表明，随着合成孔径长度和信噪比的增加，ML估计误差可以很快地收敛于CRB，但存在阈值效应。
If you know the focal ratio but not the focal length, you can calculate it: focal length is the aperture (in mm) times the focal ratio.
如果你不知道焦距，只知道焦比(focalratio)，你可以通过这样计算的得到焦距：孔径(单位是mm)乘以焦比就是焦距。
For example, the focal length of an 8" (203.2mm) aperture with a focal ratio of f/10 would be 203.2 x 10 = 2032mm.
比如，孔径为8英寸(203.2mm)，焦比为f/10的透镜，其焦距为203.2x 10 = 2032mm。
This is the ratio of the focal length of the telescope to its aperture.
这是指望远镜的焦距与其孔径的比值。
A method is introduced for testing stray light coefficient, vignetting coefficient and image surface uniformity optical system with large aperture and long focal length.
叙述一种用于测试大口径、长焦距光学系统杂光系数、渐晕系数、像面照度均匀性等光学参数的检测方法。
The longer the vessel molecule is, the smaller the aperture is, the shorter the vessel molecule is, the bigger the diameter is, the length of the fiber cell is longer.
纤维分子长度普遍大于导管分子长度，而纤维分子的口径也普遍小于导管分子的口径。
FLIR – The large aperture enables a longer focal length, which provides higher resolution without losing sensitivity.
大孔径允许更长的焦距，从而在不损失灵敏度的情况下，提供更高的分辨率。
The factors influencing the permeability characteristic and REV size of rock masses such as trace length, space, aperture, inclination and the number of joint sets are discussed.
随后讨论节理迹长、间距、开度、产状和组数等结构面几何特征对岩体渗透特性及表征单元体积的影响。
When the aperture diameter of an optical system is fixed with the same orbit height, the resolution of ground objects can be improved by increasing the focal length.
当光学系统口径一定时，在相同的轨道高度条件下，增大焦距可以提高地面分辨率，增大系统的视场角可以扩大对地面的覆盖宽度。
For large aperture lens, scanning method was developed to measure the focal length in different locations within the mirror.
针对被测镜大口径的问题，采用了扫描的方法，这样可以测量被测镜不同位置的焦距。
This works for all apertures and focal lengths, but the smaller the aperture and the shorter the focal length, and the greater the distance you shoot at, the greater the depth of field.
这在任何光圈和焦距上都适用，只不过光圈越小、焦距越短，景深越大，你能够拍摄的清晰长度就越大。
A mechanism to limit the affects of measurements on a device or system. In seismic data acquisition, the length of the spread has the effect of an aperture.
一种限制仪器或系统的测量作用的机制。地震数据采集中，排列的长度就有孔径的作用。
Screen length, incline angle, and screen-aperture are the most important screen parameters, which directly relate to the capacity and efficiency of the screen.
筛面长度、倾角和筛孔孔径是最重要的筛面参数，与筛分机的处理能力和筛分效率有着直接的关系。
So, a larger aperture can be composed, and we obtain a good purpose of increasing the length of the antenna, and we obtain a better Radar image on the orientation.
这样，利用多普勒频移现象“合成”一个更大的孔径，达到“增加天线长度”的效果，提高雷达图像的方位向分辨率。
When the diffractive optical lens is illuminated by white light, its focal length not only relates to material dispersion and wavelength dispersion, but also to aperture factor.
在白光照射下，衍射光学透镜的焦距不仅同材料色散和波长色散有关，而且还同孔径因子有关。
The aperture size (area of the aperture) of a lens could be calculated from focal length and the correspondent f-number.
光圈孔的大小，可从镜头的焦距与焦距比数中计算出来。
Therefore the adjustment of the focal length and the aperture of the optical system have direct influence on the imaging quality.
因此光学系统焦距、光圈的调节直接影响系统的成像质量。
But, if you plan to share your images on a photo hosting site and would like to indicate the focal length, aperture and other parameters to your viewers, Save for Web will not be the right method.
但是，如果你想要在网络相册中分享你的照片，并且希望观看者看到拍摄的焦距、光圈和其它参数，那么就不适合使用另存为网页格式了。
For example, a synthetic instrument with aperture of 9.2m and wave length of 4mm is specifically analysed.
做为例子，对一具口径9.2米，工作波长4毫米的综合设备进行了具体分析。
The results of test show that the air aperture number, ratio of air-liquid area, ratio of length…
结果表明，预混芯的气孔数目、气液面积比以及气泡生成室的长宽比均对喷嘴雾化效果有影响。
The results of test show that the air aperture number, ratio of air-liquid area, ratio of length…
结果表明，预混芯的气孔数目、气液面积比以及气泡生成室的长宽比均对喷嘴雾化效果有影响。
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