It shows that the lubricant with nano-Cu additive can improve the lubricating performance and reduce wear.

试验结果表明：纳米铜添加剂可以有效地提高润滑性能，减小喷油泵的磨损。

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The main substance believed to have responsible for the deaths is PIB, which is used as a lubricating additive in oils to improve performance.

BBC: Calls to stop PIB discharges at sea after bird deaths