f number

英 [ˈef nʌmbə(r)]

美 [ˈef nʌmbər]

焦距值；光圈数

英英释义

noun

• the ratio of the focal length to the diameter of a (camera) lens system
  Synonym:focal ratiostop numberspeed

双语例句

• The effective focal length and back working distance of the system are respectively 100 mm and 113 mm, while the F number is 2.0.The system which has only three lenses contains two negative germanium lenses and one positive zinc selenide lens.
  该系统全视场为14°，有效焦距为100mm，后工作距为113mm，F/2.0.系统采用锗和硒化锌两种材料，为三片镜结构。
• Based on the hydraulically and thermally developing flows, the flow and temperature fields, Nu, f and field synergy number Fc are obtained for different Re and wall temperatures.
  模拟以通道入口段的流动和换热为对象，得到了不同Re和不同壁温下的流场和温度场，对流换热的Nu和阻力系数，以及场协同数Fc。
• In the past design, under the conditions of larger discharge and energy dissipation, flow cavitation number σ f larger than incipient cavitation number σ I of the flood tunnel must be satisfied to avoid cavitation in it.
  在以往的设计中，在满足较大的泄量和消能量条件下，通常泄洪洞还要满足σf＞σi，以免发生空化空蚀。
• If diffractive efficiency is not considered, the numerical results show that larger f number microlens has smaller divergence angle.
  同时，如果不考虑微透镜的衍射效率，当球面折射微透镜的F数越大，高斯光束经过准直变换后的远场发散角越小。
• Research on Fabrication and Optical Performance Testing of Silicon Microlenses Array with Large F/ Number
  大F数硅微透镜阵列的制作及光学性能测试研究
• Papers during the theoretical analysis, but also cited a number of companies in the procurement of F found in a number of practical issues and give the corresponding solution to the problem.
  论文在进行理论分析的同时，也列举了一些F公司在采购工作中发现的一些实际问题并给出相应解决问题的办法。
• The matric characteristics and convergences on F-number space
  F数空间的度量特征及收敛性
• The method of the curve fitting with piecewise polynomials is used to derive an averaged experimental relationship f ( R) between the number of times in a year Ck and the sunspot relative number Rk ( k is the order of the years from 1980 to 1979).
  用曲线分段拟合法求出地磁扰动年次数Ck与黑子相对数Rk之间的经验的平均关系f（R）；
• The F number was 1. The lens group consisted of 3 elements.
  设计的物镜F数为1，三片式结构。
• The fill factor and F number of refractive microlens array fabricated by melting photoresist are increased by reducing developing time.
  采用缩短显影时间法改善了光刻胶热熔法制作微透镜阵列的工艺，提高了折射型微透镜阵列的F数（F）与填充因子。