介质对测量控制体位置影响的理论分析

针对用相位多普勒粒子分析仪作实际测试时，测量控制体位置变化的问题，提出了一种镜面映像法，并利用几何光学原理，成功而又简捷地推导了３层介质下平面及曲面，测量点位置变化的公式。以圆柱形曲面为例，探讨了模型壁厚和介质的影响。

Analysis of Focal Point Displacement

Encountered in measurement of PDPA is the problem of focal point displacement. Mirror image method is proposed, and with the use of geometric optics is involved focal point displacement of plane and curved surface in three layer medium is derived. Taking the cylinder, for example, the model thickness and medium effect are studied. The displacement of ideal and actual focus increases with the increment of thickness and relative refractive. Using the refractive match method, the refractive discrepancy of air and model medium are analyzed. They should not be Large in order to improve focusing.