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七十年代初,国外研制出一种超声波气压计,其最大优点是能够精密地自动测量气体的压力,测量的结果可以输送到电子计算机中进行处理,便于遥测遥控。美国国家标准局研制的超声波气压计已用来作为低、中真空的标准,它测量水银柱高度的分辨力约为10~(-8)米。超声波气压计的测量精度主要取决于水银中声速值的测量精度。据计算,水银中声速值的测量精度为10~(-5)数量级时,造成测量长度的误差约为10~(-5)
The early seventies, developed a foreign ultrasonic pressure gauge, the biggest advantage is that it can accurately measure the gas pressure automatically, the measurement results can be sent to the computer for processing, easy telemetry remote control. Ultrasonic barometers developed by the U.S. National Bureau of Standards have been used as a standard for low and medium vacuums and have a resolution of about 10 to 8 meters for measuring the height of the mercury column. The accuracy of ultrasonic barometer measurement mainly depends on the measurement accuracy of sound velocity in mercury. It is calculated that when the measurement accuracy of the sound velocity value in mercury is on the order of 10-5, the error of measurement length is about 10-5.