There could be any number of reasons this could happen: the models for the gas assume it's spherical and smooth when it may be neither, for example.

这种情况能够发生，一定有很多原因：比如，用于气体估算的模型是球形的，同时也是光滑的，但是气体可能不具有这两个特征。

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The mathematical models of the dynamic target and the tested apparatus are constructed with spherical trigonometry spherics.

运用球面三角学，建立了动态靶标与被测仪器间的数学模型；

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Panoramic images, varying according to projection models, can generally be divided into polyhedral panoramic images, spherical panoramic images and 360-degree panoramic cylinders.

全景图像根据投影模型的不同，一般可以分为多面体全景图像、球面全景图像和360度柱面全景。

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