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

• 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。
• 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 F is a number field or a infinite field.
  F是一个数域无限域。
• 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。
• 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。
• 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
• 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。
• 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。
• 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。