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问题 单项选择题

在气-液色谱法中，为了改变色谱柱的选择性，可进行的操作是 （）

A.改变载气的种类

B.改变载气的速度

C.改变柱长

D.改变固定液的种类

E.改变吸附时间

答案

参考答案：D

单项选择题

A project management team is evaluating the causes that might contribute to unsatisfactory performance and quality. Which of the following statements is not true ？（）

A．Normal process variation is attributable to random causes and sometimes also called "white noise"

B．Special causes are easier to predict and handle than random causes(also called common causes)

C．Special causes are unusual events which are difficult to foresee and mostly produce outliers

D．A process can be optimized to limit the bandwidth of variations due to random causes
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判断题

标定Na2S2O3溶液最常用的基准物是K2Cr2O7。( )
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