如何测定钢材的冲击韧性?。
钢材的冲击韧性通常采用有特定缺口的标准试件,在材料试验机上进行冲击荷载试验,使试件断裂来测
A campus emergency ______ occur at any time of the day or night, weekend, or holiday, with little or no warning.
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