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楼主 |
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 :
1 r1 U7 x2 H& o5 _$ K, K& s: SThe oscillating member is moved backwards and forwards through an angle of 90° (45° on
$ W, B" I3 C$ y7 j4 b4 seither side of the vertical), the number of flexings being 20 000 and the rate of flexing 60 per
5 i5 T& k3 @. ]1 d2 }min. A flexing is one movement, either backwards or forwards. After 10 000 flexings, the ! m- C" ?" k. N
sample is turned through 90° about the centre line of the cord guard. / H& P# M& q: m x8 c2 v* t
2 c: A9 q2 X! E1 T$ g4 X$ W: I- Z/ L+ ]....... 是的,这段话写的确实很明白,但是我估计你还是理解错了。; B* ?. H% S( C
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翻译成中文的主要意思就是:% z6 v- ~+ l2 `0 K2 B- G' [' V
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The oscillating member is moved backwards and forwards through an angle of 90° (45° on 3 P( B5 o& ?8 V: D7 g& M+ V
either side of the vertical), the number of flexings being 20 000 and the rate of flexing 60 per
1 A. F- r( P" |7 I/ omin. - 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。7 e' c' A+ ~. P$ ]
* W! b3 J2 O& E) ]! TAfter 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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1 @* @8 g5 T3 b" 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。 W- Q0 ~6 w" ~
/ v# n$ b5 |1 B4 _9 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。
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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°。 j" f& t: O7 Q
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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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