The tribological properties and the anti-wear of micron coppers inside greases were investigated by four-ball test.

通过四球试验，考察了软金属微米铜粉在润滑脂中的摩擦学行为和抗磨性。

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Four-ball wear test indicated, the borate ester and ZDDP additive are antiwear synergistic, which is much useful in developing low-phosphorus engine oils.

四球长磨实验还表明，该硼酸酯添加剂与ZDDP类添加剂具有优秀的抗磨协同作用，这对研制低磷发动机油具有重要的意义。

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The tribological properties and the anti-wear of micron copper powder in greases are investigated by four-ball test.

通过四球试验 ，考察了软金属微米铜粉在润滑脂中的摩擦学行为和抗磨性。

youdao

Proving the theory that runs are much easier with the newer, harder ball, Sehwag reached his 17th Test fifty with his sixth four.

BBC: India set Aussies daunting total

His average would have been over 100 had he scored four runs in his final Test at the Oval in 1948, but he was bowled for a duck second ball by England's Eric Hollies.

BBC: Bradman cap fetches record sum

There were some good balls, and conditions in this series have not been conducive to swatting the ball around, so there are one or two mitigating circumstances, but we should not be playing four-day Test matches.

BBC: Jonathan Agnew column