Another thing it uses ultrasound to detect is the size and shape of objects.

它还利用超声波来探测物体的大小和形状。

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Still smaller versions the size of specks of salt can be added to paint, turning entire surfaces into wireless sensors that can detect motion or act as smoke alarms or security systems.

更小一点如盐粒大小的传感器可以被掺入油漆中，把整个表面变成无线传感器——可以侦测物体的运动或是担当烟雾警报器、安全系统。

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Batteries that are the size of a grain of salt — or smaller — could power sensors that detect viruses, chemicals and more, said Philip Collins, a scientists at the University of California, Irvine.

加州大学欧文分校的的科学家菲利普·科林斯说，尺寸如盐颗粒大小的电池能够给传感器提供动力，为那些用于检测病毒和化学物质等传感器提供动力。

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The machine will be used to put markers in the body to detect the size and location of a cancer.

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Using sonar, infra-red or vision systems, suppliers are developing ways to detect the size of the passenger in the front seat and to measure how far back they are sitting.

ECONOMIST: A safety bet

Through the tap of her cane, which, like an echolocating bat, sends a small sound out into the world, she could detect the size and constituents of the space through which she was walking.

CNN: 'On Looking': The world you're not seeing