科学美国人60秒 SSS Frog Spit Behaves Like Bug-Catching Ketchup
时间:2019-01-20 作者:英语课 分类:2017年科学美国人(七)月
Frog Spit Behaves Like Bug 1-Catching Ketchup 2
青蛙唾液竟然类似番茄酱?
You might think frogs catch insects ‘cause their tongues are sticky. "But why is the tongue sticky, and how does it actually adhere to these insects at these very high accelerations 3?"
你可能会认为青蛙能够捉到昆虫是因为它们的舌头有粘性。“但为什么青蛙的舌头会很粘,而且它到底是如何做到在非常高的加速度基础上粘住这些昆虫的?”
Those are the questions Alexis Noel, a PhD candidate in mechanical engineering at Georgia Tech, wanted to answer. So she and her team got frog tongues from a dissection 4 lab, and tested their consistency 5. Ten times softer than human tongues. A texture 6 more like brain tissue. "Their tongue is very much like a sponge. It's infused with this thick, viscous 7 saliva 8."
这正是乔治亚理工大学机械工程博士生亚历克西斯·诺埃尔想要找出答案的问题。她和她的团队从解剖实验室找来一些青蛙舌头,并对它们的稠度进行了测试。结果发现,青蛙舌头比人类的舌头柔软十倍。其纹理更像脑组织。“它们的舌头很像海绵。它充满了浓浓的、粘性唾液。”
\That saliva was their next study subject. "And in order to test the saliva we had to get about a fifth of a teaspoon 9 of fluid. Which is a lot of saliva, in a frog's case." They put the saliva in a rheometer, a tool that can measure viscosity 10. And they found that frog saliva is what's called a 'shear 11-thinning fluid'—its viscosity changes, depending on conditions.
而这种唾液正是她们的下一个研究对象。“为了测试这种唾液,我们不得不搜集约五分之一茶匙的液体。而这对青蛙来说,是非常多的唾液。”她们把唾液放进一个流变仪内——一种可以测量粘度的工具。然后她们发现,青蛙唾液就是所谓的“剪切稀释液”——它的粘度会随着条件变化而变化。
You might be more familiar with a different shear-thinning fluid. "Ketchup. When you smack 12 the bottom of the ketchup bottle you're actually invoking 13 shear forces within the ketchup itself. And ketchup, because it's shear thinning, its viscosity actually drops and allows it to slide out of the bottle easily."
你可能对另一种剪切稀释液更熟悉。“番茄酱。当你掌击番茄酱瓶的底部时,实际上就是在激起番茄酱里面的剪切力。由于番茄酱会剪切稀释,因而它的粘度实际上会下降,使它能够轻易地从瓶中滑出。”
So back to our frogs: the tongue shoots out, hits the bug and deforms 14 around it. That impact is like a smack on a ketchup bottle—it changes the saliva from thick and sticky to more watery 15, free to flow all over the bug. Then the tongue bounces back, like a bungee cord, and the saliva thickens up again. What's next is beyond weird 16.
再回到青蛙的研究上来:青蛙吐出舌头,击中昆虫并导致其周围变形。这种效果就像掌击番茄酱瓶底部——它将浓稠粘性的唾液变得湿软,能够自由地将昆虫淹没。然后舌头像一个弹力绳一样反弹回来,唾液又重新变得浓稠。接下来的事情更是不可思议。
"Frogs actually take their bulbous eyeballs and bring them down into their mouth cavity and use their eyeballs to shove the insect down the throat." That force turns the saliva watery again, "and the insect slides down the gullet." The study is in the Journal of the Royal Society Interface 17.
“实际上青蛙会将它们的球状眼球带下来,放到它们的口腔中,然后利用眼球把昆虫推到喉咙里。”那股力量又会把唾液变得湿软。“然后昆虫就会向下滑向食道”。这项研究发表在《英国皇家学会界面杂志》上。
With the case closed on this one, Noel's next inquiries 18 are on grippy fingertips. The dust-collecting properties of earwax. And —wait for it— cat tongues. "Yeah, I get paid to watch cat videos all day."
这项研究完成以后,诺埃尔接下来想要研究的是令人痛苦的指尖、耳垢的收尘特性、以及猫的舌头。“是的,我整天都在看猫的视频。”
- There is a bug in the system.系统出了故障。
- The bird caught a bug on the fly.那鸟在飞行中捉住了一只昆虫。
- There's a spot of ketchup on the tablecloth.桌布上有一点番茄酱的渍斑。
- Could I have some ketchup and napkins,please?请给我一些番茄酱和纸手巾?
- The two particles will undergo accelerations as a result of their interaction. 这两个粒子由于相互作用将获得加速度。 来自辞典例句
- Since the cord connecting the two blocks is inextensible, the accelerations are the same. 由于连接两物块的绳子无伸缩性,因此它们的加速度相同。 来自辞典例句
- A dissection of your argument shows several inconsistencies.对你论点作仔细分析后发现一些前后矛盾之处。
- Researchers need a growing supply of corpses for dissection.研究人员需要更多的供解剖用的尸体。
- Your behaviour lacks consistency.你的行为缺乏一贯性。
- We appreciate the consistency and stability in China and in Chinese politics.我们赞赏中国及其政策的连续性和稳定性。
- We could feel the smooth texture of silk.我们能感觉出丝绸的光滑质地。
- Her skin has a fine texture.她的皮肤细腻。
- Gases are much less viscous than liquids.气体的粘滞性大大小于液体。
- The mud is too viscous.You must have all the agitators run.泥浆太稠,你们得让所有的搅拌机都开着。
- He wiped a dribble of saliva from his chin.他擦掉了下巴上的几滴口水。
- Saliva dribbled from the baby's mouth.唾液从婴儿的嘴里流了出来。
- The viscosity shows a rather pronounced variation with temperature.温度对粘度的影响十分明显。
- The reciprocal of viscosity is known as fluidity.粘度的反意就是流动性。
- Every spring they shear off the sheep's wool and sell it.每年春天他们都要剪下羊毛去卖。
- In the Hebrides they shear their sheep later than anywhere else.在赫伯里兹,剪羊毛的时间比其他任何地方都要晚。
- She gave him a smack on the face.她打了他一个嘴巴。
- I gave the fly a smack with the magazine.我用杂志拍了一下苍蝇。
- You can customise the behavior of the Asynchronous Server and hence re-brand it by defining your own command set for invoking services. 通过定义自己调用服务的命令集,您可以定制自定义异步服务器的行为,通过为调用服务定义自己的命令集从而对它重新标记。 来自《简明英汉词典》
- You can customize the behavior of the Asynchronous Server and hence re-brand it by defining your own command set for invoking services. 通过定义自己调用服务的命令集,您可以定制自定义异步服务器的行为,通过为调用服务定义自己的命令集从而对它重新标记。 来自辞典例句
- Bad rheumatoid arthritis deforms limbs. 严重的类风湿性关节炎会造成四肢变形。
- The specimen deforms under a tensile stress applied parallel to the fibres. 试样在平行于纤维的张应力作用下发生变形。
- In his watery eyes there is an expression of distrust.他那含泪的眼睛流露出惊惶失措的神情。
- Her eyes became watery because of the smoke.因为烟熏,她的双眼变得泪汪汪的。
- From his weird behaviour,he seems a bit of an oddity.从他不寻常的行为看来,他好像有点怪。
- His weird clothes really gas me.他的怪衣裳简直笑死人。
- My computer has a network interface,which allows me to get to other computers.我的计算机有网络接口可以与其它计算机连在一起。
- This program has perspicuous interface and extensive application. 该程序界面明了,适用范围广。