Validity and feasibility of the finite difference time domain method is demonstrated by the echo-wave signal of a flat bottom hole block.
通过与平底孔试块实际缺陷回波信号的对比，验证了脉冲超声波有限差分法模拟计算的有效性和正确性。
2
But an oak which has fewer but bigger leaves with stronger reflections, produces a jagged wave form, or what we called a rough echo.
但是，橡树的叶子少而又大，反射力较强，会产生参差不齐的声波，或所谓的“粗糙回声”。
3
High frequency ground wave radar for near ocean inspection and ocean remote sensor is a method that use ocean echowave Dopier spectrum to deduce the parameters of ocean situation.