Doppler shift

简明释义

多普勒频移

英英释义

例句

1.The sound of a passing ambulance changes pitch due to the Doppler shift (多普勒效应).

经过的救护车声音的音调因Doppler shift (多普勒效应)而变化。

2.In medical imaging, the Doppler shift (多普勒效应) helps visualize blood flow in arteries.

在医学成像中，Doppler shift (多普勒效应)有助于可视化动脉中的血流。

3.The Doppler shift (多普勒效应) can explain why the pitch of a train whistle sounds higher as it approaches.

当火车接近时，Doppler shift (多普勒效应)可以解释为什么火车鸣笛的音调听起来更高。

4.Astronomers use the Doppler shift (多普勒效应) to determine if a star is moving towards or away from Earth.

天文学家利用Doppler shift (多普勒效应)来判断一颗星星是朝向地球移动还是远离地球。

5.The radar system detects the speed of a car using the Doppler shift (多普勒效应) of the reflected waves.

雷达系统通过反射波的Doppler shift (多普勒效应)来检测汽车的速度。

作文

The concept of Doppler shift is an essential phenomenon in physics that describes the change in frequency or wavelength of a wave in relation to an observer who is moving relative to the wave source. This effect can be observed with any type of wave, including sound, light, and electromagnetic waves. The Doppler shift is named after the Austrian physicist Christian Doppler, who first proposed this idea in 1842. Understanding this principle is crucial for various applications in science and technology, ranging from astronomy to medical imaging.In everyday life, we can easily observe the Doppler shift when a moving vehicle approaches and then passes by. As the vehicle comes closer, the sound waves it produces are compressed, resulting in a higher pitch. Conversely, as it moves away, the sound waves are stretched, leading to a lower pitch. This observable change in sound frequency is a direct application of the Doppler shift and illustrates how motion affects wave properties.In the realm of astronomy, the Doppler shift plays a pivotal role in understanding the universe. By analyzing the light emitted from distant stars and galaxies, astronomers can determine whether these celestial bodies are moving toward or away from Earth. A shift towards the blue end of the spectrum indicates that an object is approaching, while a shift towards the red end signifies that it is receding. This principle has led to significant discoveries, such as the expansion of the universe, which was first evidenced by Edwin Hubble's observations of redshift in distant galaxies.Moreover, the Doppler shift is not limited to sound and light; it also applies to other types of waves. For instance, in medical imaging, ultrasound uses the Doppler shift to visualize blood flow within the body. By emitting sound waves and measuring the frequency changes as they bounce off moving red blood cells, doctors can assess the speed and direction of blood flow. This application is invaluable in diagnosing various medical conditions, including heart disease and vascular disorders.The mathematical representation of the Doppler shift involves the use of formulas that take into account the speed of the observer and the source of the waves. For sound waves, the formula can be expressed as: f' = f (v + vo) / (v + vs) where f' is the observed frequency, f is the source frequency, v is the speed of sound in the medium, vo is the speed of the observer relative to the medium, and vs is the speed of the source relative to the medium. For light waves, the calculations become more complex due to the effects of relativity, but the fundamental concept remains the same.In conclusion, the Doppler shift is a fascinating and vital concept that bridges multiple fields of study. Its implications extend far beyond simple sound waves, influencing our understanding of the cosmos and enhancing medical technologies. As we continue to explore the universe and advance our scientific knowledge, the principles behind the Doppler shift will undoubtedly remain a cornerstone of our exploration and discovery efforts.

“多普勒效应”是物理学中的一个基本现象，描述了波的频率或波长在与波源相对运动的观察者之间的变化。这个效应可以在任何类型的波中观察到，包括声波、光波和电磁波。“多普勒效应”以奥地利物理学家克里斯蒂安·多普勒的名字命名，他于1842年首次提出这一概念。理解这一原理对于科学和技术的各种应用至关重要，从天文学到医学成像。在日常生活中，我们可以轻易观察到“多普勒效应”，当一辆移动的车辆靠近然后经过时。随着车辆的靠近，它发出的声波被压缩，导致音调升高。相反，当它远离时，声波被拉伸，导致音调降低。这种声音频率的可观察变化是“多普勒效应”的直接应用，说明了运动如何影响波的特性。在天文学领域，“多普勒效应”在理解宇宙方面发挥着关键作用。通过分析来自遥远恒星和星系的光，天文学家可以确定这些天体是朝向地球还是远离地球。光谱向蓝色端的偏移表示物体正在接近，而向红色端的偏移则表明它正在远离。这一原理导致了重大的发现，例如宇宙的扩张，最初是通过埃德温·哈勃对遥远星系红移的观察而证实的。此外，“多普勒效应”不仅限于声波和光波；它还适用于其他类型的波。例如，在医学成像中，超声波利用“多普勒效应”可视化体内的血流。通过发射声波并测量它们在反弹回移动的红细胞时的频率变化，医生可以评估血流的速度和方向。这一应用在诊断各种医疗条件（包括心脏病和血管疾病）中具有重要价值。“多普勒效应”的数学表示涉及使用公式，考虑观察者和波源的速度。对于声波，公式可以表示为：f' = f (v + vo) / (v + vs)其中f'是观察到的频率，f是源频率，v是介质中的声速，vo是相对于介质的观察者速度，vs是相对于介质的源速度。对于光波，由于相对论的影响，计算变得更加复杂，但基本概念仍然相同。总之，“多普勒效应”是一个迷人且重要的概念，连接了多个研究领域。它的影响远不止简单的声波，影响着我们对宇宙的理解，并增强了医学技术。随着我们继续探索宇宙和推进科学知识，“多普勒效应”背后的原理无疑将继续成为我们探索和发现努力的基石。