本文采用远场光斑法和光强法测量了石英单模光纤的数值孔径.实验结果表明,由光纤耦合条件不同导致的光斑形状变化,对数值孔径的测......

Accidents such as support failure and excessive deformation of roadways due to drastic changes in stratabehaviors are fr......

测量船基地现有标校塔与测量船距离只有980m,无法满足高频段统一X频段（UXB）系统天线的远场标校距离条件.针对这一难题,提出了一种利......