| 释义 |
DictionarySeeDoppler effectEncyclopediaSeedoppler, christian j.Doppler, Christian Andreas
Doppler, Christian Andreas (dop'ler) Austrian mathematician and physicist, 1803–1853. Doppler echocardiographyThe use of ultrasound technology to determine the velocity of blood flow in different locations in the heart but esp. across the heart valves.Doppler effectThe variation of the apparent frequency of waves, e.g., sound, light, and radio waves, with a change in distance between the source and the receiver. The frequency seems to increase as the distance decreases and to decrease as the distance increases. Doppler measurement of blood pressure and fetal heart rateThe use of Doppler sound waves to determine fetal systolic blood pressure or the fetal heart rate.Doppler velocimetryThe use of Doppler ultrasound to determine the speed of blood flow through arteries and veins. During pregnancy Doppler ultrasonography can determine whether blood flow rates are adequate in the uterine artery, placenta, and umbilical cord vessels. See: uteroplacental insufficiency |