It is important first to identify the noise source, the receiver, and the couplingmedium.
分析的第一步最重要，即确定噪声源、接收方和耦合介质。
2
Up till now, there is no accurate standard for the optimum acoustic impedance of the couplingmedium.
目前国内超声医学界对最佳耦合剂声阻数值的选择尚无较为准确的说法。
3
The EMAT is characteristic of non-contact and being needing no couplingmedium, so it is specially concerned by researchers on nondestructive testing and evaluation.