paraxial

based on the nonlinear paraxial wave equation, the propagation equation of small-scale perturbation of divergent beams has been deduced with a coordinate transformation. the evolvement law of the growth critical frequency of small-scale perturbation, maximum growth frequency and relative b integral is obtained.

从非线性傍轴波动方程出发，利用坐标变换，推导出发散光束小尺度扰动的传输方程，进而得到小尺度扰动增长的临界频率、最大增长频率和相应B积分值的变化规律。

the parameters of optical surface of concave-convex infrared lens which can focus laser beams to achieve the output laser beams with lesser output angle and longer focus field. it has been calculated according to paraxial approximation, matrix theory and step by step searching methods.

根据旁轴矩阵、以及分步搜索法寻找到满足输出光束具有较小的出射角、较长焦深的凹凸红外透镜的光学表面参数。

in the embryo an undifferentiated mesodermal component of an early trunk or tail segment or metamere, derived from paraxial mesoderm.

在胚胎时，一个无法区别的中胚层组成一个早期躯干、或尾部片段或体节，衍生自轴旁的中胚层。