中心矩

The symmetry no longer existed when the projection of light source is not located in the symmetry center of rectangular aperture.

当光源的孔面投影不在矩孔中心时光强分布的对称性不复存在。

In this thesis, two main parts are included, the first focuses on the characteristics of high-resolution spectra of free radicals in magnetic field, the second concentrates on the measurement of electric dipole moment of free radicals by Zeeman and Stark effects simultaneously.

本论文以电磁场中自由基分子的光谱与结构特性研究为中心，主要内容包括两部分，一是针对磁场中自由基分子高分辨光谱的特性研究，另一部分则是同时利用电磁场中自由基分子的Zeeman和Stark效应，对自由基分子的电偶极矩进行直接测量研究。

By equivalent principle, formulae for all equivalent main force, main moment and shear center of the distribution shear and the result of numerical simulation were given. Finally relationship between dynamic shear and static shear was presentedatoo.

应用力系等效原理，给出分布剪力的等效主矢量、主矩和剪力中心表达式及数值模拟结果，以及动态体表剪力与静态体表剪力的关系。

During numerical integration the triple integral is time consuming and divergent when the number of higher waveguide modes increases.

本文首先建立波导宽边中心倾斜孤立辐射裂缝的积分方程，然后用矩量法求解得到了孤立缝的S参数及归一化等效阻抗。

For example, pressure,distance,nozzle hole diameter, line-number of swirling object, screw-pitch of swirling object and central hole of swirling object.

考察了工作压力、靶距、喷嘴孔径、加旋件头数、加旋件螺矩、及加旋件中心孔对钻孔效果的影响。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。