Half-value layer(hvl)
[化] 半值层; 半值厚度
🧩 词语组成解析
half
[hæf]
adj. 一半的，半个的;
n. 半;一半;（啤酒等饮料的）半品脱;（比赛、音乐会等的）半场;
adv. 一半;部份地;
🗣️ 情景例句
what you need to fix up the old library.
你们修复旧图书馆所需要的东西。
Money spent on the brain is never spent in vain.
智力投资，决非虚掷。
This is because they had no natural enemies until the arrival of humans and therefore did not need to develop flying wings.
这是因为人类到达这里之前，这些鸟没有天敌，因此，它们不需要发育飞行的翅膀。