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。

youdao

Randlett Lawrence’s frontyard sculpture, “Phantasma Gloria, ” rises above the street in a glittering cobalt blue wave, swaying in the breeze in the Echo Park neighborhood of Los Angeles.

在洛杉矶回声公园附近的街边，矗立起兰德利特·劳伦斯的前院雕塑作品：“幻影颂歌”。 它摇曳在微风中，钴蓝色的波纹闪闪发光。

youdao

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”。

youdao