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pH值在4.0-5.5之间时，随着pH值的增大，转化率和选择性随着增大。采用并流，当老化时间相同时，随着老化温度的增加，催化剂的转化率和选择性增大；当老化温度相同时，随着老化时间的增加，催化剂的转化率和选择减小。随着沉淀温度的增加，催化剂的粉料堆密度增大；随着堆密度的增大，催化剂的转化率和选择性减小。

PH between 4 .0-5.5 time, with the pH value increases, the conversion rate and increases with selective. The introduction and flow, when the same aging time, with the increase of aging temperature, the catalyst of conversion and selectivity increases; When the aging temperature the same, as the aging time, the catalyst for the conversion and reduced choice. Along with the increase in precipitation temperature, the catalyst powder bulk density increases; With the increased bulk density, catalyst for the conversion and selectivity decreased.

转化率是conversion rate不是transform rate

cocurrent可能得改改

还有was the same

催化剂是catalyst不是activator

沉淀化学里都用这个词precipitate,（这是名词）
deposition是沉积物，沉积作用

When the PH value was between 4.0 and 5.0, along with the increase of the PH value, tra