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1 超声波的物理性质与生物学效应超声波系指大于2 0 0 0 0 0Hz的声波,此声波不能被人所听见,目前常见医学超声波仪的超声频率为0 .8～32MHz。超声波用于医学诊断的最大优点:①超声波具有一定方向性。②它遵循反射和折射的原则。③它可以被小物体所反射,其不足之处是在含气物体
1 The physical properties and biological effects of ultrasound Ultrasound refers to the sound waves greater than 20000Hz, the sound waves can not be heard, the current common ultrasonic frequency ultrasonic medical instrument is 0.8 ~ 32MHz. The biggest advantage of ultrasound for medical diagnosis: ① ultrasound has a certain direction. ② It follows the principle of reflection and refraction. ③ It can be reflected by small objects, the downside is the gas-bearing objects