focal ratio

1. The application of focal mechanism determinations of moderate-small earthquakes in Yunnan Province using the first motion and amplitude ratio of P and S wave
   用P波、S波初动和振幅比计算中小地震震源机制在云南地区的应用
2. Study of the Tests of Large-aperture and Fast Focal Ratio Convex Hyperboloid Mirrors with a "Stitching" Method
   大口径快焦比凸双曲面拼接检测方法研究
3. It has many advantages to determine the focal mechanism by using SH and P wave amplitude ratio, but requires highly for the distribution of stations.
   用SH波和P波振幅比测定地震震源机制具有诸多优点，但它对台站布局要求较高。
4. Determination of focal mechanism using SH to p amplitude ratio
   用SH波和P波振幅比确定震源机制解
5. Given the laser intensity, the optimum focal size increases with the pulse width, and the ratio of the optimum focal size to the pulse width is fixed.
   在相同激光强度下，电子能量增益的最佳焦斑大小随脉冲宽度的增大而增大，但最佳焦斑大小与脉冲宽度的比值基本上是不变的。
6. Focal point at the ratio of transmission calculating, every gear wheel torsion of the differential gear wheel system distributing and the Accident analysis and scheme of transforming for the stretcher straightener, We have carried on the detailed discussion to study.
   本文重点拉弯矫正机差速器传动系统的对传动比及效率计算、差速齿轮系统各齿轮扭矩分配、齿轮承载能力计算，气垫炉拉弯矫正机设备故障分析及改造方案进行了详细的讨论研究。
7. Conclusion The neuroprotective effects of aspirin on focal cerebral ischemia-reperfusion injury in rats for 72 h might be attributed to its effects by anti-apoptosis, increasing the ratio of Bcl-2/ Bax, inhibiting the activity of CaN, and improving the energy metabolism.
   结论阿司匹林对脑缺血/再灌损伤72h有明显保护作用，其机制可能与抗凋亡、提高Bcl2/Bax、改善能量代谢及对钙调神经磷酸酶的影响有关。
8. The focal ratio of the Cassegrain system for the telescope is F/ 10 and the plate scale is 20 ″/ mm.
   该望远镜卡焦焦比为F/10，底片比例尺为20〃/mm，无畸变象场约为1平方度天区。
9. It designs two estimating experiments to obtain the focal length value corresponding to the minimum CCD focal length, from which the ratio of the CCD focal length to its optical equivalent is derived.
   设计两种测量CCD等效焦距的实验方法，分别利用物像距离与物像长度的比例关系和平行双目成像原理，得到与CCD焦距极值对应的等效焦距。
10. The results indicated: the imaging distance of PS transformation related mainly to focal length of imaging lens, the system magnifying power related mainly to the ratio between the imaging lens focal length and holographic lens focal length.
    推导表明，PS变换成像的距离是较稳定的，主要与成像透镜焦距有关，系统放大率主要与成像透镜焦距和全息透镜焦距之比有关；
11. The results show that the focal, field and remote precursory anomalies are of the following characteristics: The spatial distribution of anomalies is inhomogeneous, the distribution of anomalous monitoring stations of focal precursors is concentrated, and the anomaly ratio can reach 90%;
    结果表明，源、场、远兆异常有如下特征：异常空间展布不均，源兆空间内异常监测点展布“密集”、异常比例可达90%；
12. Moreover, the amount of the focal shifts depends on the Fresnel number of the focusing lens, the spatial coherence of the partially coherent light and the central obstruction ratio of the annular lens etc.
    并且，焦移量不仅依赖于透镜外半径的菲涅耳数，还依赖于部分相干光的空间相干度和中心拦截比。
13. Determination of Focal Mechanism by Using SH and P Wave Amplitude Ratio
    利用SH波和P波振幅比测定中小地震的震源机制
14. Using geometry theory and the Monte Carlo method study its 'geometric optical characteristics and focal plane density distribution, and consider influence of different error on geometric concentrating ratio and the flux density distribution.
    利用几何学原理和MonteCarlo方法研究新型多平面太阳能聚光器的几何光学特征及焦平面能流密度分布，分析不同综合误差对几何聚光比及能流密度分布的影响。

noun

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

   Synonym:    f numberstop numberspeed