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引用第10楼franco于2009-05-07 20:39发表的 :& A7 A% m2 |# s% m
The oscillating member is moved backwards and forwards through an angle of 90° (45° on
5 i' M2 Y4 c: Y+ x8 Ceither side of the vertical), the number of flexings being 20 000 and the rate of flexing 60 per
/ }2 c7 R. o( A( |8 P1 a" hmin. A flexing is one movement, either backwards or forwards. After 10 000 flexings, the # N7 }( ?4 K( Y5 C N% e2 I
sample is turned through 90° about the centre line of the cord guard.
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. M7 H7 i' U, H. Z1 C翻译成中文的主要意思就是：
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The oscillating member is moved backwards and forwards through an angle of 90° (45° on
* ?4 b0 }, [* {3 F2 Ceither side of the vertical), the number of flexings being 20 000 and the rate of flexing 60 per ) i3 L( o. S" p
min. - 摇摆装置能够在90°的范围内前后摆动（其中这个90°指的是沿垂直位置两边各45°），以每分钟60次的频率摇摆20000次。
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4 F! G P$ V! `这句话讨论的是仪器的摆动机构要满足的特性，就是要能在90°的范围内前后摆动，如果只能在45°的范围内摆动的话，这个设备就是不符合要求的。这句话并没有涉及到一个摆动周期如何定义啊。! A$ B. {4 A5 |+ _8 ]* f
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After 10 000 flexings, the sample is turned through 90° about the centre line of the cord guard. - 10000次摆动之后，将样品沿着电线防护套的中心线转动90°。
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这句话说的是总共20000次的摆动样品应该在两个位置分两次完成而已，同样没有涉及到摆动周期的解释和说明。7 \# C2 F' t7 e/ c# g! W4 U
1 I% p2 X. F, }( D最重要的一句话应该是：A flexing is one movement, either backwards or forwards. - 一次摇摆就是一次移动，无论是向后还是向前的。, o0 J+ t1 \1 S5 Z
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这句话虽然容易引起歧义，但是仔细考虑一下也不是很难理解。可以看出，1个摆动周期就是单次的向前或者向后的移动。摇摆机构是在总共90°范围内摆动，那不管是向前还是向后的摆动角度都是45°了。由此可以得出1个摇摆周期就是45°而不是我们通常认为的90°。
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. D' e5 ]$ }9 s0 \, `" z摘抄UL 745-1标准中的相关章节如下，关于这个问题解释的非常清楚，供大家参考参考：
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A flexing is one movement, either backwards or forwards. That is, from vertical to 45° in one direction is the first flex, from there back to vertical is the second flex, from vertical to the opposite 45° is the third flex, from there back to vertical is the fourth flex, continuing until 10000 flexes have occurred. |
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发表于 2009-5-7 20:39
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