Steel's fragility at low temperatures first became a major concern during the Second World War.

第二次世界大战，材在低温下易碎性首次成为人们关注重点。

Brittleness remains a problem when building steel structures in cold conditions, such as oil rigs in the Arctic.

在寒冷条件下建造材结构，比如北极地油钻塔，易碎性仍然是一个问题。

However, RCT permanently deprives vitality and sensitivity from thetooth, consequently increasing the friability of the remaining tooth.

然而, RCT永久性地剥夺了牙齿活力和敏感性, 从而增加了剩余牙齿易碎性。