The process of changing an open-chain hydrocarbon structure to a closed ring, e. g. , hexane to benzene.

使开链烃结构变成闭环烃的过程，例如使己烷变成苯。

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Its chemical properties are similar to those of alkanes, but its molecule is in the form of closed ring.

其化学性质与烷烃相似，但其分子是闭环形式。

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The two theorems are proved that any ring can be extended into an algebraically closed ring and that the quaternionic skew field over a real closed field is algebraically closed.

证明了任一环有代数封闭的扩张环，且实封闭域上的四元数体是代数封闭的，给出了代数封闭环的若干性质。

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Mr Miliband urged the PM to stop any of the centres being closed by reinstating the ring-fence around their funding.

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Grapes Hill on the inner city ring road was closed for several hours as vehicles struggled to get up its steep slope.

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Since the plant closed, Janesville, which sits almost at the center of a ring of major cities, including Milwaukee, Chicago, St.

NEWYORKER: Fussbudget