In both cases, these cycles can result from new requirements, correction of initial mistakes, various types of structural improvements, and so on.

这些周期在两种情况下都源于新需求、初始错误的纠正、各种结构化改进，等等。

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According to analyze the structure of survival rocket and identify its vulnerable spots, necessary structural improvements are put on overall lock and the hermeticity of igniter tube.

通过对火箭包的结构进行分析，确定薄弱环节，对整体防松和点火管密封性进行了必要的结构改进。

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Improvements are introduced containing: material selection, structural design, manufacturing process and layout of supporting points of plane plate.

文中对平板材料的选择，结构设计，制造工艺和支承方法的改进进行了论述。

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There may well have been structural improvements in emerging economies, but just now markets are having none of it.

ECONOMIST: Emerging markets

While oil and metals prices can carry an economy for a little while, sustained growth invariably comes down to structural improvements in technology and productivity, asserts van Ark.

FORBES: Magazine Article

But as Mr Coulton points out, it is not clear how much of this increase was structural (the product of enduring improvements in tax collection) and how much cyclical (the result of a temporary upswing in the economy).

ECONOMIST: Fretful markets fear the worst