Such distinct constitutive parameters have brought the medium several quite unique electromagnetic properties, such as negative refraction, reversed Doppler effect, reversed Cerenkov radiation, etc.

其独特的本构参数给予了这种介质独特的电磁特性，比如负折射、逆多普勒效应、逆（?）

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However because of the refraction effect in the troposphere there is refractive error in the parameters measured in positioning system.

但由于对流层中的折射效应，定位系统所测目标的仰角、距离等参量均存在一定的折射误差。

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The parameters of the optical structure were given by analyzing the optical pathway diagram based on formulas of refraction and reflection.

本文根据折反射定律，通过分析光路图，给出了此光学系统的结构参数。

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