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发表于 2009-5-8 15:06
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引用第10楼franco于2009-05-07 20:39发表的 :$ K- g6 I. b& J, e
The oscillating member is moved backwards and forwards through an angle of 90° (45° on ' I: O! }6 ?$ ~* X% |9 B
either side of the vertical), the number of flexings being 20 000 and the rate of flexing 60 per
z8 x3 ?3 U& d, y. Y9 mmin. A flexing is one movement, either backwards or forwards. After 10 000 flexings, the 9 p- }' U+ d" I7 w
sample is turned through 90° about the centre line of the cord guard.
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....... 是的,这段话写的确实很明白,但是我估计你还是理解错了。8 s% x, j; ^$ G5 s4 ~. O
% L4 \; J% Z( S' q/ [, P9 @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 ) N( r! X* R5 |( O
either side of the vertical), the number of flexings being 20 000 and the rate of flexing 60 per ! ?4 d% ]+ X& C2 T; \1 k( Z" f. i
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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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。: V6 f* g" G4 e8 Z1 J: }& G) |0 r4 v; y
4 x; x0 Z# i, v' g$ R) C8 X+ F( kAfter 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°。3 _& ?3 M- L/ U. i7 z
8 j( J9 g% i3 L4 I7 X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。 d \. o7 \# I/ ], W# f
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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。
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' w8 o6 ]4 c) ]) _- \- Q, j/ K. }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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# Y# t/ D {; p# z1 s/ ]$ N0 t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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% k' ^& H9 u# l7 K vA 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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