来自《耶鲁大学开放课程：新生有机化学 第6集 第6集》

• 
  
  And the spots weaken successively because of wire thickness,
  而因为螺线具有一定的厚度
• 
  
  as we just explained, as you go on out.
  成像位置越远 亮点的亮度越低
• 
  
  Now, that looks very much like
  这就和富兰克林在1952年得到的
• 
  
  Rosalind Franklin's b-DNA photograph from 1952.
  B型DNA的图片很相像了
• 
  
  So we see the helix
  我们得到了这个衍射图案
• 
  
  and we see how angled the successive turns of the helix are,
  并从X两臂间的角度
• 
  
  what the pitch of the helix is,
  得到了螺旋的螺距
• 
  
  and from the spacing of the dots we get how big the actual helix is.
  从这些小点的间距知道了螺旋的实际大小
• 
  
  But there's something funny.
  现在有趣的来了
• 
  
  The intensity doesn't just evenly decrease as you go out.
  沿臂的光强度并未随距离增加逐渐减弱
• 
  
  Instead of being strong, not quite as strong, less strong,
  本来随着距离的增加
• 
  
  weaker, very weak, as you go out,
  光应该逐渐地由强变弱