如果进行积分的球面域小于半球面，反演将是唯一的。

If the integrated area is less than half spherical surface, inversion will be unique.

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在变换后的球面域上用球谐函数来拟合速度函数，达到降低球谐系数阶数的目的。

Representing velocities by spherical harmonic expansion on the sphere after transformation can greatly reduce the number of spherical harmonic coefficients needed.

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目的研究凹球面超声换能器的声焦域在高声强和媒质有较大衰减情况下，其形状和几何位置的变化。

Objective the variations of the site and shape of focal region for a concave spherical ultrasound transducer in the case of high sound intensity and stronger attenuation were studied.

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