The optical band gap between nano-TiO 2 energy band and conduction band is3.

纳米二氧化钛能带和导带之间的带隙能为3。

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As the concentration of caustic ion in the Yellow River water is3 ~ 4times more than the under-groundwater.

由于黄河水中腐蚀性离子的浓度是原地下水的3 ~ 4倍，导致了循环水腐蚀速率大幅度升高。

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