Neutral medium, it should be chosen for the copper alloy shell material valve solenoid valve, or valve shells falling debris often rust, especially the movements do not frequent occasions.

中性介质，也宜选用铜合金为阀壳材料的电磁阀，否则，阀壳中常有锈屑脱落，尤其是动作不频繁的场合。

youdao

Such as material aging, not perfect, the craft falling behind, consuming greatly, high cost, unsteady production, and low output mass in these entry-level step's sign kilns.

这些初级阶段的立窑装备老化、不完善，工艺落后，消耗大，成本高，生产不稳定，产量质量低，它们正处于被淘汰的处境。

youdao

And then we return here to focus, as I mentioned, with 46 other countries, on locking down any vulnerable nuclear material over the course of the next four years to ensure that we are not faced with that kind of material falling into the hands of a terrorist organization.

WHITEHOUSE: Press Briefings