您要查找的是不是：
- Self-focusing and defocusing of narrow radio beam in lower ionosphere 无线电窄波束在低电离层中的聚焦和散焦
- Narrow radio beam 窄波束
- The radio beam came from outer space. 这个无线电波束来自外太空。
- Like the searchlight beam, the radio beam cannot be made very sharp; it tends to spread. 无线电射束也象探照灯的光束一样，是不能高度集中的；它总要散开。
- Ironically, the detailed reasons as to how the radio beam is produced may not be important astronomically. 具有讽刺意义的是,产生射电波束的详细原因在天文上,这也许并不重要。
- And the spacecraft's antenna will receive a powerful radio beam from Earth passing through Pluto's atmosphere. 来自地球的强大无线电波能穿透冥王星大气层，为太空船的天线所接收。
- It is much easier to steer the radio beams electronically. 以电子方式控制无线电波束，会简单许多。
- The transmitter stays put,with its radio beam pointing in the direction we wish to explore,and the sail travels along the beam,picking up momentum from the radio saves. 发射器固定不动，它的无线电波指向我们希望深测的方向；探测器沿着电波的方向运动，从无线电波获取动力。
- And when the array transmits back to the cell-phone user, the processor sends an out-of-phase signal to one of the antennas, generating a radio beam that runs from north to south. 当阵列发射讯号给行动电话用户时，处理器会传送一个异相的讯号到其中一个天线，产生由北往南的无线电波束。
- The transmitter stays put, with its radio beam pointing in the direction we wish to explore, and the sail travels along the beam, picking up momentum from the radio saves. 发射器固定不动，它的无线电波指向我们希望深测的方向；探测器沿着电波的方向运动，从无线电波获取动力。
- A radio beam. 无线电波
- The road is too narrow to allow the passage of gondola. 这条街太窄，大型货车不能通过。
- The mountain path is narrow and rugged. 狭隘的山路崎岖不平。
- The travelers edged warily along the narrow road. 旅游者沿着狭窄的小路小心前行。
- A chill struck into the narrow of his bones. 他感到一股寒意，透入骨髓。
- A transistorize radio takes no time to warm up. 晶体管收音机不需要预热时间。
- The tide flushed through this narrow inlet. 潮水涌过了狭窄的小湾。
- A gem cut in the form of a narrow rectangle. 狭长形宝石被切成细条形的宝石
- She performed on the balance beam with much grace. 她在平衡木上表演得非常优美。
- She turned the car into the narrow street. 她驱车拐进狭窄的街道。
