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B.must be watered
C.must water
D.must be watering
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更多“Where are Rose and Nancy? -They ____ the flowers in the garden.”相关的问题
第4题
第6题
A、decorated
B、interact
C、wrench
D、beckoning
第7题
B.Please pick me up next time
C.I've been to the airport
D.The plane will take off in an hour
第10题
A.I have just bought a new one
B.It’s cheap to repair a motorcar
C.Around the street corner
D.You drive too fast to damage it
第11题
将英语短文译为中文
3 Self-Powered Nanotech (10分)
Nanosize machines need still tinier power plants
By Zhong Lin Wang
The watchmaker in the 1920s who devised the self-winding wristwatch was on to a great idea: mechanically harvesting energy from the wearer’s moving arm and putting it to work rewinding the watch spring.
Today we are beginning to create extremely small energy harvesters that can supply electrical power to the tiny world of nanoscale devices, where things are measured in billionths of a meter. We call these power plants nanogenerators. The ability to make power on a minuscule scale allows us to think of implantable biosensors that can continuously monitor a patient’s blood glucose level, or autonomous strain sensors for structures such as bridges, or environmental sensors for detecting toxins — all running without the need for replacement batteries. Energy sources are desperately needed for nanorobotics, microelectromechanical systems (MEMS), homeland security and even portable personal electronics. It is hard to imagine all the uses such infinitesimal generators may eventually find.
In Brief
★Nanotechnology has huge potential — but those minuscule devices will need a power source that is better than a battery.
★ Waste energy, in the form. of vibrations or even the human pulse, could provide sufficient power to run such tiny gadgets.
★ Arrays of piezoelectric nanowires could capture and transmit that waste energy to nanodevices.
★ Medical devices will likely be a major application. A pacemaker’s battery could be charged so it would not need replacing, or implanted wireless nanosensors could monitor blood glucose for diabetics.
