Yes, type "U" refers to Unknown for the Nominal Annual Rate.

是的，“U”型指的是未知的名义增长率。

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J41N Type PN40 steel globe valves: manual, flanged, straight-through, the valve seat sealing surface material as nylon plastic, nominal pressure PN40, carbon steel valve body material cut-off valve.

J 41 n型PN 40钢制截止阀：手动、法兰连接、直通式、阀座密封面材料为尼龙塑料、公称压力pn 40、阀体材料为碳素钢的截止阀。

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According to the fatigue type, use safe-life design method to study tower crane's fatigue, and choose nominal stress approach to estimate the life of tower crane.

并根据其疲劳类型，确定选用安全寿命设计方法对塔式起重机钢结构进行疲劳分析，并应用名义应力法估算塔式起重机钢结构的疲劳寿命。

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This type of nominal GDP growth has often been associated with the onset of recession, as opposed to the notion of robust economic growth.

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