Noun:

1. increase by a factor of two;

   "doubling with a computer took no time at all"
   

2. raising the stakes in a card game by a factor of 2;

   "I decided his double was a bluff"
   

doubleadj.双重的；成双的；两倍的v.翻一番；使 ... 加倍n.两倍；双份

1. But still well under a doubling of speed.
   但是速度提高也不过是两倍。
2. The doubling of the sale force result in increase sale.
   双倍的销售力量导致增加了销售额。