Question

    Thomas Wallin at Cornell University in New York and his colleagues have created soft robotic grippers(机械爪）that are capable of sweating to cool down.

The grippers are capable of a cooling capacity of 107 watts per kilogram,making them more efficient sweaters than mammals.By comparison,humans and horses have a maximum cooling capacity around 35 watts per kilogram.

Each gripper consists of three finger-like parts that bend simultaneously(同步地）to grasp small objects.The 3D-printed grippers are made from hydrogels -materials which can store large amounts of water.Each finger is made from an underlayer with an internal channel to let fluid flow and is capped with a surface layer containing micropores(微孔）。

At cold temperatures,the pores close.At temperatures higher than 30C,the surface layer expands,enabling pressurised fluid from the underlayer to sweat out.The material responds simultaneously to temperature changes without the need for external sensors.

＂Sweating takes advantage of evaporative water loss to rapidly dissipate(使消散）heat,”said Wallin in a press briefing yesterday.Unlike convection or radiation,sweating lowers the temperature of a body below that of its environment,he said.

＂When the local temperature rose above the transition,the pores would simply open on their own,"said Wallin.

When blown by wind from a fan,the sweating robots cooled at a rate of 39.1C per minute, about six times faster than similar devices that are unable to sweat.The technique could be used to help robots operate for long periods of time without overheating,said team-member Robert Shepherd,also at Cornwell.

However,there is currently no means for the robot to replenish(补充）its fluid stores after sweating.This means"the robots that operate via the autonomous sweating that we've created would have to also be able to drink",said Shepherd.

1.What is the most distinct feature of soft robotic grippers?

A.They can cool themselves down by sweating.

B.They can grasp objects like human fingers.

C.They can store large amounts of water.

D.They're 3D printed and can bend.

2.What is the fundamental principle behind the sweating of robotic grippers?

A.Three parts of each gripper bend at the same time.

B.The external sensors detect the temperature change.

C.Heat expands the material and squeezes the liquid out.

D.Radiation lowers the temperature below the environment.

3.We can conclude from the last paragraph that the robots

A.can sweat by themselves

B.need to be refilled with water

C.can sense thirst and drink water

D.can work long without overheating

Answer

1.A

2.C

3.B

【解析】

这是一篇说明文。文章介绍了康奈尔大学研制出了通过自主“流汗”来降温的机械臂，主要说明了机械臂的降温原理及其优点。

1.细节理解题。根据第一段“Thomas Wallin at Cornell University in New York and his colleagues have created soft robotic grippers(机械爪）that are capable of sweating to cool down.”可知，这种机械爪的最大特点就是能通过“排汗”来降温。故选A项。

2.细节理解题。根据第四段第二句“At temperatures higher than 30C,the surface layer expands,enabling pressurised fluid from the underlayer to sweat out.”可知，当外界温度较高时，机械爪表层就会扩展，从而将加压的水排出来，这就是其工作原理。故选C项。

3.推理判断题。根据最后一段“However,there is currently no means for the robot to replenish(补充）its fluid stores after sweating.”可知，目前还没有补充液体储存的手段，容易想到后文中所指代机械爪也要“喝水”，指在储水用完后需要补充水。故选B项。