f number

1. You can really think of it as the sum of the values of f everywhere divided by the number of points everywhere.
   可以认为这是所有点处f值的和，再除以所有点的数。
2. F any product on which the serial number has been removed, defaced or modified.
   任何产品上的序列号已被删除，涂改或修改。
3. The results show that under increasing pressure the band occupation numbers change, with s and p electron number gradually transferring to d and f electron number.
   结果表明，随着压强的增加，能带电子占据数发生变化，s分波和P分波电荷逐步向d分波和f分波电荷转移；电声矩阵元中p（？）
4. 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）；
5. The ray tracing method and vectorial Stratton Chu diffraction Integration are applied in the analysis of the imaging performance over the focal planes of hyperbolic lens and reverse microscope lens system with small F number.
   采用射线追迹结合StrattonChu矢量衍射积分公式的方法分析计算了小F数双曲透镜和倒置显微镜的焦面成像特性。
6. A computing method of f he number of lateral sides and the coordinates of vertices of a mixture CONVEX-POLYHEDRON having lower and upper bounds
   兼有上、下界约束混料凸多面体的面数与顶点坐标的一种计算方法
7. 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。
8. Study of F Number of Microlenses for Collimation of Laser Diode Arrays
   阵列激光微透镜准直器透镜F数的研究
9. 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。
10. The matric characteristics and convergences on F-number space
    F数空间的度量特征及收敛性
11. 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。
12. 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。
13. 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。
14. 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。
15. 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。
16. 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。
17. 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
18. The F is a number field or a infinite field.
    F是一个数域无限域。
19. 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。
20. 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
21. 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
22. The optical performance of small F number diffractive microlens arrays little voice
    小F数衍射微透镜阵列光学性能研究
23. Methods Testing patients 'pronunciation with of without complete denture and contrast with normal speech sounds. Using USSA to analyes its frequency and parameter number of wave crest ( F) and energy number ( P).
    方法对无牙颌患者戴全口义齿前、后与正常对照组进行语音a/i/u的检测并对其共振峰参数频率值（F）、能量值（P）的USSA语音频谱的分析。
24. 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。
25. This paper analyses colour subcarrier quantization noise in PCM coding of complete television singal. The relationship between quantization noise and sampling frequency ( f s) as well as quantizing bit number ( n) is discussed.
    分析了全电视信号PCM编码色度副载波量化噪声，并讨论了量化噪声与取样频率fs和量化比特数n的关系。
26. A modified first-derivative based QRST detection algorithm as well as a proposed adaptive f wave number detection algorithm was utilized in the method, and new conditions was set for AF detection.
    该方法应用了改进的一阶差分QRST检测算法和提出的自适应f波波数检测算法，并设置了新的房颤检测条件。
27. 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。
28. The injection rate is the average interarrival time, the multicast size is the number of destination nodes, and the message length f is the number of flits in a message.
    注射率的平均间隔时间，多目传播大小是指目的节点的数量，消息长度f是一个消息的字节流的数量。

noun

1. the ratio of the focal length to the diameter of a (camera) lens system

   Synonym:    focal ratiostop numberspeed