双透镜的

A double-pass schlieren system using a combination of lenses and mirrors was designed for non-intrusive visualization and measurements of large-field flows such as internal waves.

为了实现对内波等流场的大视场无干扰竖向显示测量，设计了一种透镜和反射镜结合使用的平面反射双光程形式的纹影系统。

The biconic lens includes an external surface defined by two different curves disposed substantially orthogonal to one another, a major curve C1 and a minor curve C2, wherein C1 and C2 intersect at or near the optical axis.

双锥形透镜包括由两个分别为主要曲线C1和辅助曲线C2且在光轴或接近光轴的位置上C1和C2相交基本正交的不同曲线所限定的外表面。

Based on the propagation and transformation law of Wigner distribution function through a general axially nonsymmetrical optical system,investigated is the transform relationship of WDF between the input and the output planes of a pair of cylindrical lenses system which is used widely in optical signal processing .

基于维格纳分布函数在一般非轴对称系统的传播和变换规律，讨论了在光学信息处理系统中常用的双柱透镜系统输入和输出面WDF之间的变换关系，在直角坐标中给出了联系该系统相空间坐标的维格纳分布函数的坐标变换关系式和等价的矩阵表示。

In the course of testing, the laser was used as light source with twin-light path, dispelled the error of light-intensity variation of traditional detection devices, the measurement result only relates to the relative change of optical intensity .

测量以激光为光源，采用双光路法，消除了通用检测仪由于光源光强不稳定产生的误差，使得测量结果只与光强的相对变化量有关；光波出入波导均采用棱镜耦合，减少了普通测试方法因样品质量及面形误差和端面洁净情况不同或输出透镜不能很好汇聚光波而产生的误差；利用常规仪器设备实现了数字化检测显示，避免了人为主观读数产生的误差；利用AD538实时模拟计算芯片，提高了计算精度和运算速度。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。