What is the critical value of laboratory testing?

The detection critical value refers to the condition that a physical quantity must meet when an object changes from one physical state to another, which is equivalent to the stagnation point in mathematics. Therefore, it is an important method to solve the maximum and minimum values of physical quantities by using critical state. Some people think that it is prudent to solve the maximum value with critical state, and the relationship between the two States must be distinguished first.

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