The ratio of the focal length of a lens or lens system to the effective diameter of its aperture.
光学仪器的目镜上的细线、圆点、十字型细线或金属丝组成的系统。
The ratio of the focal length to the diameter of a lens system.
颅骨最大长度和最大宽度的比率。
A variable-focus lens with 2mm in diameter and focus turning range from 20.33mm to 9.36mm based on different liquids in the chamber was carried out from this investigation.
实验以直径2mm之透镜来做探讨，其所能变焦之范围大约在20.33mm至9.36mm之间，依据腔体内所充满之液体而有所不同。
The maximal diameter of lens and the overall weight of this eyepiece are 26 mm and 7 g, respectively.
该目镜的最大镜头直径为26 mm，总重量为7 g。
Microfiber Products detail: Microfiber refers to the so-called 0.4uM of the micro-diameter fibers, its fiber silk degrees only 1/10 special wedge-shaped cross-section to enable it to more effectively capture even a few microns of dust particles, decontamination, to oil the effect is very obvious. 75:25 of polyester/nylon ratio, making material is extremely soft, on the swab surface without any harm, even in the field of high precision, such as lens coating, large scale integrated circuit manufacturing process can also be assured that the use of its water volume, water absorption speed is ordinary cotton fabric for more than 5 times.
所谓超细纤维是指直径0.4uM的微纤维，其纤维度仅为真丝1/10特殊楔型横截面，使它能更有效地捕获甚至几微米的尘埃微粒，除污、去油的效果十分明显。75：25的聚脂/耐纶比，使得质料极其柔软，对被拭物表面无任何伤害，即使在高精密领域里如镀膜镜头、大规模集成电路生产过程中也能够放心使用，其吸水量、吸水速度是普通棉织物的5倍以上。
The anterior sub-capsular epithelial cells adherent to the porcine lens capsule were dissected into the central (6 mm, diameter) and the peripheral regions.
解剖显微镜下分离晶状体前囊膜，将附着于其上的上皮细胞分为中央（直径为10.56mm）和周边两部分。
Stop Down: To decrease the diameter of the light-admitting orifice of a lens by adjustment of an iris diaphragm.
缩小光圈：镜头的焦距和光圈的有效直径之间的关系。一可调节的彩虹光阑，减少透镜光孔的直径。
This paper first derived the relationship between NA and the height/diameter ratio as a dimensionless geometric parameter of lens via thick-lens theory. Geometric characteristics for lens with high NA are analyzed and simulated. Effects of different substrates on the NA of microlens, fabricated by reflow process using photoresist, are also investigated.
本研究利用厚透镜理论推导数值孔径与球形透镜无因次化参数高径比的关系，再透过模拟分析找出NA较高的几何型态，并且探讨利用热熔法制作此类型微透镜时，不同基材特性对微透镜NA的影响。
While coupling one end of the bundles to the target area of the IR TV camera thr ough the lens system, the other end was aimed at a 3mm diameter hole at 5m away. This small hole had been homogeneously injected by ideal radiator.
前、后两端分别配置可调焦的红外透镜，入端对准5m处400℃黑体炉φ=3mm的小孔，出端与热像仪连接，经过光学扫描和信号处理后，在计算机屏幕上显示出圆形的黑体？
Results and Conclusions: Our simulations show that in order to improve the focal shape, the outer diameter of the annulus must be as large but the radius of acoustic lens must be as small as possible.
结果与结论：为了改善椭球焦域长短轴之比，环状外径应尽量取大，声透镜半径应尽量取小；
The anteroposterior diameter of the STN nucleus was longer than the diameters of upper-down and left-right in 3D. The 3D reconstruction of STN manifested typical structure of " dual lens ", and AM nucleus displayed the typical anatomical characteristics of " amygdaloid ".
STN前后径较长，上下径和左右径相对较短，表现出典型的双透镜结构特点，而AM则表现出典型的杏仁形状。
Make use of fase locked loop and cosine approximate compensate method for laser scanning measuring diameter without F - θ lens, reach a high measure precision.
采用锁相环和余弦近似补偿的激光扫描测量直径，不用F－θ透镜而达到测量精度。
The ratio of the focal length to the diameter of a (camera) lens system.
相机镜头直径焦距比。
The measurement method and error analysis method of GRIN lens focal spot diameter in IR wavelength are described.
主要介绍GRIN透镜在红外波段聚焦光斑直径的测量方法及误差分析。
The improved optical scanning system consisting of a beam expander, a galvanometric scanner with automatic self-calibra - tion and an f-theta lens can get a laser light spot with the diameter of 0.012 mm on the focal plane.
由扩束镜、高精度扫描振镜及f-θ透镜构成扫描系统，扫描面上的激光光斑直径达到0.012mm。
The working performance of the probe has been testified by measuring the flatness and thickness of a standard gauge block and the diameter of a convex lens.
通过对标准量块的平面度、厚度以及一个有效直径约为6mm的凸透镜的测量，验证了探头的有效性。
The imaging formulas of the Gaussian beam through a large diameter step-index rod lens are derived and can reduce to the geomertical optics imaging formulas under the geometrical optics condition.
导出了高斯光束经大直径阶跃折射率棒透镜的成像公式，在几何光学条件近似下，所得公式可简化为几何光学成像公式。
Results: This 76-year-old man had senile cataracts and received phacoemulsification of the right eye. After temporal clear corneal incision, 0.4 ml of a viscoelastic agent was injected into the anterior chamber. Continuous curvilinear capsulorhexis was performed with a bent 27-gauge needle and a capsular forceps. The diameter of the CCC was 3 mm without radial tear. After hydrodissection with 0.3 ml of balanced salt solution at 6 o`clock, dim red reflex of the lens and shallow anterior chamber were found.
结果：一位七十六岁男性右眼有老年性自内障，接受超音波晶体乳化术，颞侧角膜切开后，前房注入人工玻璃体0.4毫升，利用27号弯针及前囊撕开镊进行连续性前囊切开术，前囊切开的直径为3毫米，注入0.3毫升的平衡盐溶液，将囊袋及水晶体核分离时，红反射变暗，及前房变狭窄，再注入0.2毫升的平衡盐溶液时，前房突然变深，后囊破裂，水晶体核向玻璃体空腔倾斜，因此诊断为术中水晶体包囊阻塞症候群。
This paper calculates the radius of curvature of lens exactly by using average method to measure the diameter of Newton's rings.
本文通过用平均值法测定牛顿环的直径，解决了牛顿环直径测不准的问题，从而精确地计算出透镜的曲率半径。
A preliminary study of the measurement of optic disc diameter with 78 D lens and biomicroscope
应用活组织显微镜和78D透镜测量视乳头直径的初步研究