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

• Improving the Fill Factor and F Number of Refractive Microlens Array by Reducing Developing Time
  通过缩短显影时间提高微透镜阵列的填充因子与F数
• The F number standard for concrete floor developed by american concrete Institute and Canadian Standards Association is superior to the standard known as the gep under a straight edge. This paper briefly introduces its significance and application metod on site.
  介绍了美国混凝土学会和加拿大标准学会的F数标准，以及使用该混凝土地面平整度和水平度标准的现实意义和现场测量方法。
• Investigation on space optical system of high F number and high resolution
  大F数高分辨率空间望远镜光学系统
• The degree of a face f in G ( written r ( f)) is the number of edges of G incident with f, each cut edges counting as two edges.
  一个面所关联的边的个数（割边要计算两次），被称为面的度，用r（f）表示。
• The results were correlated in term of j and f as a function of Reynolds number and the geometrical parameters of heat exchangers by multiple linear regression technique.
  通过多元线性回归法将实验数据整理为以雷诺数和换热器几何参数为自变量的j和f关联式。
• 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
• The author presents a method of calculating the error of location and analyses the relationship between the error of location and the frequency difference of double-frequency grating ( or the amount of shear) and F number of the system.
  文中提出了计算定焦误差的方法，分析了定焦误差与双频光栅的频率差（或剪切量）及系统的F数之间的关系。
• 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 matric characteristics and convergences on F-number space
  F数空间的度量特征及收敛性
• 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。