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Anyone who has experimented as a child with maize starch and water knows about shear-thickening.
任何在童年做過玉米淀粉加水實驗的人都知道剪切增稠。
A mixture of these substances is easy to stir slowly, but solidifies when you speed the stirring up, only to liquefy again when you stop.
慢慢攪拌這些物質的混合物很容易，但當你加速攪拌時，混合物會凝固，只有當你停止攪拌時，它才會再次液化。
It's fun. But it may also be important. For years, people have been trying to apply the principle to armour. Now, it seems, one group has succeeded.
很有趣，但也很重要。多年來，人們一直嘗試將這個原理應用于裝甲部隊?，F在有一組團隊似乎已經成功了。
The result will not stop a speeding bullet. But, incorporated into a helmet, it might save the wearer from concussion.
結果是，它無法阻止一顆飛速的子彈，但如果與頭盔結合在一起，或許可以讓佩戴者免于腦震蕩。
Construction workers, soldiers and sportsmen and women all wear safety helmets
建筑工人、士兵、運動員都要戴安全帽
that contain impact-absorbing suspension systems based on foam pads or webbing straps.
其中含有基于泡沫墊或織帶的可吸收沖擊的懸架裝置。
Eric Wetzel of the United States Army Research Laboratory and his colleagues propose replacing these
美國陸軍研究所的Eric Wetzel和他的同事提議將這些替換成
with fabric tubes containing a shear-thickening material that the lab has developed.
由實驗室研發的一種含有剪切增稠材料的織物圓筒。
These tubes, which behave like viscous, speed-sensitive bungee cords, are known as rate-activated tethers, or RATS.
這些類似粘性、速度敏感型彈力繩的織物圓筒被稱為速率激活拴繩或RATS。
A standard bungee cord's useful property is its elasticity. This first stores energy as the jumper falls and then releases it as he bounces back up again.
標準彈力繩的有用特性是它的彈性。現在蹦極者跳下去的時候儲存能量，然后在彈起時釋放能量。
A RAT bungee jump, however, would be a one-way trip. RATS absorb energy when stretched in the way that an elastic substance does,
但RAT彈力繩將是一次單程旅行。當以彈性物質的方式拉伸時，RATS吸收能量，
but, unlike an elastic, they do not then give it back when released. That would leave a jumper dangling at the bottom.
但與彈性物質不同的是，它們在被松開時不會釋放能量。這樣將會讓蹦極者在底部晃蕩。
Dr Wetzel's team were developing RATS as ankle supports to absorb landing shock for parachutists
Wetzel博士的團隊正在研發RATS作為一種吸收跳傘者著陸時震動力的踝護
when they realised that the tethers they were working with had just the qualities required for helmet suspensions:
當時他們意識到，他們使用的拴繩擁有頭盔懸架所需的品質：
they provide instant strong resistance, which increases with impact speed.
它們提供即時強大的抵抗，這增加了沖擊速度。
Existing military helmets protect in situations like travel over rough terrain, collisions between vehicles and with obstacles,
現有的軍用頭盔能夠在崎嶇地形、車輛和障礙物之間的碰撞
and being thrown around by bomb blasts. RATS offer better protection in all these cases.
以及被炸彈炸得四處亂飛等情況下起到保護作用。
Current American-army combat helmets are built to withstand impact velocities of three metres a second,
目前美國陸軍的戰斗頭盔能夠承受3米每秒的沖擊速度，
with newer models being rated for just over four. Prototype helmets fitted with RAT suspension pass impact tests at five metres a second,
而最新型號的頭盔只能承受4米多每秒的沖擊速度。配有RAT懸架的原型頭盔以每秒5米的速度通過了撞擊測試，
which Dr Wetzel says no previous helmet suspension has achieved.
Wetzel博士說，之前的頭盔懸架還沒有達到這一水平。
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