一种曲面测量方法

本发明公开了一种曲面测量方法，用于采集曲面上的多个点的位置数据，该方法包括：将待测曲面划分为多个三角区域，其中所述三角区域为三维空间的平面三角形，其三个顶点位于所述曲面上；所述三角区域的特征距离小于或者等于一预定的阀值，所述特征距离是指三角区域内的一特征点在曲面上的投影点到所述三角区域的距离；将所述三角区域的顶点作为测量点，并测量该测量点的位置数据。本发明的曲面测量方法着重于曲面上测量点的选取，充分利用了待测曲面的几何特性，使得测量点的分布在曲面曲率大的地方密，小的地方疏，减少了冗余数据，大大提高了测量效率和测量速度

Determination of the number of ψ(3686) events taken at BESIII

The number of ψ(3686) events collected by the BESIII detector during the 2021 run period is determined to be (2259.3±11.1)×106 by counting inclusive ψ(3686) hadronic events. The uncertainty is systematic and the statistical uncertainty is negligible. Meanwhile, the numbers of ψ(3686) events collected during the 2009 and 2012 run periods are updated to be (107.7±0.6)×106 and (345.4±2.6)×106, respectively. Both numbers are consistent with the previous measurements within one standard deviation. The total number of ψ(3686) events in the three data samples is (2712.4±14.3)×10^