SSS 2012-06-07
时间：2012-07-20 06:47:42
搜索关注在线英语听力室公众号：tingroom，领取免费英语资料大礼包。
（单词翻译）
Sometimes women and men break a nail working on a tough task. Because our keratin claws are no match for the club-like appendages1 of a critter called the peacock mantis2 shrimp3. They can hammer through crab4 exoskeletons and even mollusk5 shells to find a meal. They can even smash through glass.
Researchers drilled down to the nanoscale to determine what makes the tiny shrimp clubs so tough. Turns out there are three sections to the club. There’s an extremely hard impact region made of hydroxyapatite, or HA. That’s also found in vertebrate bones and teeth.
The HA is backed by an array of rods of chitosan, another hard substance found in
crustacean6 and insect exoskeletons. The chitosan array protects against fractures. The sides of the claw are less stiff, and act sort of like shock-absorbers. The research is in the journal Science.
The resulting composite is
optimized7 for high-velocity offensive strikes. It can
inflict8 maximum damage with
minimal9 internal cracks.
In an accompanying commentary in the journal, scientists say that understanding the structure could have implications in, for instance, designing
lighter10 armor that’s less likely to fracture. Or perhaps an improved crab
mallet11.
Thanks for the minute for Scientific Americans 60 second Science, I am Cynthia Graber.
分享到：
Error Warning!
出错了
Error page: /?aid=182360&mid=3
Error infos: Got error 28 from storage engine
Error sql: select `l`.`tag`,`l`.`index`,`l`.`level_id`,`b`.`id`,`b`.`word`,`b`.`spell`,`b`.`explain`,`b`.`sentence`,`b`.`src` from `new_wordtaglist` `l` left join `new_word_base` `b` on `l`.`tag`=`b`.`word` where `l`.`arc_id`='182360' and `l`.`level_id`>='' group by `b`.`word` order by `l`.`index` asc
