小钢球 meaning in English

shot

Thirdly , through assaying the error generated during measuring data , the result manifests : 1 ) the location installed of the transducer and the point thumped affects the experiment result to some extent . if surface - opening cracks is deeper , the location of the transducers installed and the point thumped should be further away from the location of surface - opening cracks . 2 ) when the depth of surface - opening cracks is near to 50mm , it is very difficult to measure the depth of surface - opening cracks because the depth of r _ wave conveying in concrete plates from the different small ball bringing forth exceeds 50mm . 3 ) it is clear from the experiment result , the influence is n ' t big for the diameters of small balls to measure the data while the time interval between two transducers touched firstly has very big influence on the result
其次，对测量数据进行了误差分析，结果表明： ( 1 )传感器及敲击点的位置对实验结果有一定的影响，当开口裂纹的深度较深时，传感器和敲击点的位置应该离裂纹较远； ( 2 )当开口裂纹深度接近50毫米时，由于实验中所使用的小球产生的r波传播深度均超过50毫米，故很难测量出其开口裂纹的深度； ( 3 )实验发现，小钢球直径的大小对裂纹深度的测量结果影响并不是很大，但是，波的开始上升和下降点的测量精度(即两信号的时间延迟) ，对测量的结果有很大的影响。