GE began selling Lexan in 1957. A potential replacement for glass and metal, it was used for everything from electric coffeemakers to the light covers on the wings of supersonic aircraft.

通用从1957年开始销售聚碳酸酯以逐步取代玻璃和金属，它的应用非常广泛，从电子咖啡机到超音速飞行器的表面材料。

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Considering the critical components like reactor coolant lines and oil-well casings, the metal parts are subjected to prior replacement, for safety, with respect to a worst-case analysis of failure.

考虑到关键部件如反应堆冷却剂线和油井涂层不能出现问题，为了安全，并对失效做了最坏的分析，这类金属零件会得到优先更换。

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Valve Advantages: The replacement of elastomeric packings by metal diaphragms gives this valve superior leak integrity at the top works of the valve and stem.

阀门的优点：用金属横膈膜代替人造橡胶衬垫在阀门和阀杆的顶部机件处给予了这种阀门出众的泄漏完整性。

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These replacement joints can be made of combinations of metal alloys, plastic and ceramic, but new research shows that it might be possible to regenerate damaged joints using a patient's own stem cells.

VOA: standard.2010.08.11

He said: "I would not want a metal on metal hip replacement" preferring instead to go for ceramic on ceramic.

BBC: Fears over hip replacements