Nrov science paub txogultrasound
Whether it's a health check-up or a visit to the hospital, doctors always ask patients to have an ultrasound. Most people's understanding of ultrasound is that pregnant women need B-ultrasound, but in fact, ultrasound is not only used for pregnant women to check the fetus, this is only a small part of the application of ultrasound in clinical medicine. But what exactly is ultrasound? How does it examine the human body?
Ultrasound, that is, ultrasound, is a mechanical wave. The frequency of sound waves that can be heard by the human ear is between 20 and 20 000 Hz. When the vibration frequency of sound waves is greater than 20 000 Hz or less than 20 Hz, we cannot hear them. Therefore, we call sound waves with frequencies higher than 20 000 Hz "ultrasonic". Ultrasonic has the characteristics of good directionality, strong penetrating ability, easy to obtain relatively concentrated sound energy, long distance in water, etc. It can be used for distance measurement, speed measurement, cleaning, welding, gravel, etc., in medicine, military, industry, agriculture widely used.
Lub ultrasonic zaus feem ntau siv rau kev kuaj mob yog 210MHz. Nws tuaj yeem taug kev hauv lub cev thiab cuam tshuam qee qhov nws rov qab los tom qab ntaus cov ntaub so ntswg sib txawv. Raws li cov cuab yeej ntawm lub cev no, cov kws tshawb fawb tau tsim ntau yam cuab yeej ultrasonic. Lub ultrasonic yoj yog generated thiab emitted los ntawm kev sojntsuam. Tom qab nkag mus rau tib neeg lub cev, ib feem ntawm lub yoj ultrasonic yog rov qab los raws li qhov sib txawv ntawm cov khoom siv acoustic ntawm tib neeg lub cev thiab cov ntaub so ntswg, thiab tom qab ntawd tau txais los ntawm kev sojntsuam thiab ua tiav los ntawm lub khoos phis tawj, tso tawm thiab taug qab hauv daim ntawv ntawm waveforms, nkhaus. los yog duab. , Ultrasonography yog ib txoj kev kuaj mob uas tus kws kho mob ultrasound tuaj yeem paub qhov txawv ntawm lub cev thiab cov kab mob pathological raws li cov yam ntxwv ntawm daim duab.
