VOA标准英语2014--Tiny Fly May Hold Key to New Generation of Hearing Aids

 

Tiny Fly May Hold Key to New Generation of Hearing Aids

Ormia ochracea, a tiny yellow parasitic¹ fly native to Central America and the southern United States, has an unusual habit.

It deposits larvae² onto the backs of crickets, which burrow³ into the insects and consume them from the inside out.

The fly locates its host by listening for the cricket's high-pitched chirp⁴, which it can hear from as far away as the length of a football field, and pinpoint⁵ its location.

It's something no other insect can do. In fact, O. ochracea's ear structure is so unique that it's now the model for what may be a new generation of hypersensitive hearing- and sonic-aid devices.

“The fly has a clever mechanism⁶ that instead of using two independent ears, like a human would, the fly’s ears are actually coupled,” says Professor Neal Hall, an acoustic⁷ engineer at the University of Texas, Austin.

With ears set two millimeters apart — a separation so slight that sound reaches one ear just four millionths of a second before arriving at the other — O. ochracea also an internal feature that resembles a tiny see-saw. At only 1.5 millimeters long, this latter feature is forced into motion by the pressure of soundwaves, which increase the sound delay and allow the fly to zero in on its prey⁸.

In the journal Applied⁹ Physics Letters, Hall and colleagues at the University of Texas report on a prototype of the fly’s hearing structure they built, based on previous studies.

They copied the see-saw mechanism in silicon¹⁰ and used special electric materials to measure its flex¹¹ and rotation¹².

The prototype, they found, localizes audible sound just like the fly.

After discerning the motion of the structure, the researchers then computed¹³ the direction of the sound source.

Hall sees applications of the work moving in two directions: on the battlefront, where sensors¹⁴ would be critical to localize where shots are originating, and in health care to supply hearing devices that could filter out distracting background sound.

“One thing the fly teaches us how to do is to hear in a certain direction, while rejecting sound coming from other directions," he said. "That is a feature that is incredibly useful for hearing aids, for example, where right now, if you turn up the gain of a hearing aid or turn up the volume to hear someone across from you, it also amplifies¹⁵ everything else in the room."

Hall says the remaining challenge in bringing such products to market is making them practical to handle.

"Because the device is so small, it is delicate," a concern the fly does not have to worry about, he says.

1 parasitic   

adj.寄生的

参考例句：

• Will global warming mean the spread of tropical parasitic diseases?全球变暖是否意味着热带寄生虫病会蔓延呢？
• By definition,this way of life is parasitic.从其含义来说，这是种寄生虫的生活方式。

2 larvae   

n.幼虫

参考例句：

• Larvae are parasitic on sheep.幼虫寄生在绵羊的身上。
• The larvae prey upon small aphids.这种幼虫以小蚜虫为食。

3 burrow   

vt.挖掘(洞穴)；钻进；vi.挖洞；翻寻；n.地洞

参考例句：

• Earthworms burrow deep into the subsoil.蚯蚓深深地钻进底土。
• The dog had chased a rabbit into its burrow.狗把兔子追进了洞穴。

4 chirp   

v.(尤指鸟)唧唧喳喳的叫

参考例句：

• The birds chirp merrily at the top of tree.鸟儿在枝头欢快地啾啾鸣唱。
• The sparrows chirp outside the window every morning.麻雀每天清晨在窗外嘁嘁喳喳地叫。

5 pinpoint   

vt.准确地确定；用针标出…的精确位置

参考例句：

• It is difficult to pinpoint when water problems of the modern age began.很难准确地指出，现代用水的问题是什么时候出现的。
• I could pinpoint his precise location on a map.我能在地图上指明他的准确位置。

6 mechanism   

n.机械装置；机构，结构

参考例句：

• The bones and muscles are parts of the mechanism of the body.骨骼和肌肉是人体的组成部件。
• The mechanism of the machine is very complicated.这台机器的结构是非常复杂的。

7 acoustic   

adj.听觉的，声音的；(乐器)原声的

参考例句：

• The hall has a fine acoustic.这个大厅的传音效果很好。
• Animals use a whole rang of acoustic, visual,and chemical signals in their systems of communication.动物利用各种各样的听觉、视觉和化学信号来进行交流。

8 prey   

n.被掠食者，牺牲者，掠食；v.捕食，掠夺，折磨

参考例句：

• Stronger animals prey on weaker ones.弱肉强食。
• The lion was hunting for its prey.狮子在寻找猎物。

9 applied   

adj.应用的；v.应用，适用

参考例句：

• She plans to take a course in applied linguistics.她打算学习应用语言学课程。
• This cream is best applied to the face at night.这种乳霜最好晚上擦脸用。

10 silicon   

n.硅(旧名矽)

参考例句：

• This company pioneered the use of silicon chip.这家公司开创了使用硅片的方法。
• A chip is a piece of silicon about the size of a postage stamp.芯片就是一枚邮票大小的硅片。

11 flex   

n.皮线，花线；vt.弯曲或伸展

参考例句：

• We wound off a couple of yards of wire for a new lamp flex.我们解开几码电线作为新的电灯花线。
• He gave his biceps a flex to impress the ladies.他收缩他的肱二头肌以吸引那些女士们的目光。

12 rotation   

n.旋转；循环，轮流

参考例句：

• Crop rotation helps prevent soil erosion.农作物轮作有助于防止水土流失。
• The workers in this workshop do day and night shifts in weekly rotation.这个车间的工人上白班和上夜班每周轮换一次。

13 computed   

adj.[医]计算的，使用计算机的v.计算，估算( compute的过去式和过去分词 )

参考例句：

• He computed that the project would take seven years to complete. 他估计这项计划要花七年才能完成。 来自《简明英汉词典》
• Resolving kernels and standard errors can also be computed for each block. 还可以计算每个块体的分辨核和标准误差。 来自辞典例句

14 sensors   

n.传感器，灵敏元件( sensor的名词复数 )

参考例句：

• There were more than 2000 sensors here. 这里装有两千多个灵敏元件。 来自《简明英汉词典》
• Significant changes have been noted where sensors were exposed to trichloride. 当传感器暴露在三氯化物中时，有很大变化。 来自辞典例句

15 amplifies   

放大，扩大( amplify的第三人称单数 )； 增强； 详述

参考例句：

• Gain is the number of times the amplifier amplifies a signal. 增益就是放大器放大信号的倍数。
• Such panicky behaviour amplifies the impact of the Russian export ban. 这样的恐慌行为放大了俄罗斯小麦出口禁令的影响效应。