However, the approximation error can be large under harsh lighting conditions, thus making it difficult to recover albedo information.
然而，在苛刻光照条件下，这种近似的误差往往比较大，以至于很难恢复出反射率信息。
Though W grade can be increased, it is difficult to better recover tungsten with mechanical beneficiation methods.
矿石中钨品位虽可得到提高，但采用机械选矿方法却难以较好回收。
Though W grade can be increased, it is difficult to better recover tungsten with mechanical beneficiation methods.
矿石中钨品位虽可得到提高，但采用机械选矿方法却难以较好回收。
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