(A) A．locating B．abbreviation C．ranging D．sense E．survivors F．reflected G．tell H．in I．qualities． J．off K．short L．barriers Superman isn’t the only one who can see through solid matter. Researchers in Atlanta, Ga, have invented a radar flashlight that can detect a person’s presence through walls and doors. Radar is 40 for radio detecting and receiving. The radar flashlight gives 41 radio waves, some of which are 42 by solid materials and some of which penetrate materials 43 in thickness from clothing to walls and doors. The penetrating radio waves then bounce off people and objects on the other side of walls and doors and are reflected back through those 44 to the radar flashlight. To 45 whether a living person is behind a barrier, the device uses a computer chip to analyze the reflected radio waves. The chip is programmed to 46 slight variations in radio reflections that indicate a heartbeat or respiration and the process of breathing. “These 47 make the flashlight potentially useful to police officers in ambush situations and to prison guards doing bed checks, said Gene Greneker, a researcher at the Georgia Institute of Technology. Other uses for the technology include 48 people in a room during a hostage situation, based on radar reflections of their movement or breathing, and finding 49 in the ruins of earthquakes, fires, or accidents. 【查看更多】
