“phase angle”的概念、定义、翻译、参考文献-科学参考

phase angle

Physics

The difference in phase between two sinusoidally varying quantities. The displacement x₁ of one quantity at time t is given by x₁=asinω‎t, where ω‎ is the angular frequency and a is the amplitude. The displacement x₂ of a similar wave that reaches the end of its period T, a fraction β‎ of the period before the first is said to lead the first quantity by a time β‎T; if it reaches the end of its period, a fraction β‎ of the period after the first quantity it lags by a time β‎T. The value of x₂ is then given by x₂=asin(ω‎t+ϕ‎). ϕ‎ is called the phase angle and it is equal to 2πβ‎.

Astronomy

The angle between the Sun and an observer as seen from the centre of a body in the Solar System. At a phase angle of 0° the Sun and observer lie in exactly the same direction, and so the observer sees the object fully illuminated. At a phase angle of 180° the Sun and observer lie on opposite sides of the body, and the whole of its unilluminated side is facing the observer.

Geology and Earth Sciences

The angle, usually termed α‎, formed by lines joining the centres of the Earth, the Sun, and another solar system object. Aristarchus of Samos (3rd century bc) measured the Earth–Sun–Moon angle for the first lunar quarter and thus established that the Sun was much more distant than the Moon.

单词	phase angle
释义	phase angle Physics The difference in phase between two sinusoidally varying quantities. The displacement x₁ of one quantity at time t is given by x₁=asinω‎t, where ω‎ is the angular frequency and a is the amplitude. The displacement x₂ of a similar wave that reaches the end of its period T, a fraction β‎ of the period before the first is said to lead the first quantity by a time β‎T; if it reaches the end of its period, a fraction β‎ of the period after the first quantity it lags by a time β‎T. The value of x₂ is then given by x₂=asin(ω‎t+ϕ‎). ϕ‎ is called the phase angle and it is equal to 2πβ‎. Astronomy The angle between the Sun and an observer as seen from the centre of a body in the Solar System. At a phase angle of 0° the Sun and observer lie in exactly the same direction, and so the observer sees the object fully illuminated. At a phase angle of 180° the Sun and observer lie on opposite sides of the body, and the whole of its unilluminated side is facing the observer. Geology and Earth Sciences The angle, usually termed α‎, formed by lines joining the centres of the Earth, the Sun, and another solar system object. Aristarchus of Samos (3rd century bc) measured the Earth–Sun–Moon angle for the first lunar quarter and thus established that the Sun was much more distant than the Moon.
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