根据信号、本底的时间分布以及时间、时间误差、质量、质量差等变量之间的关系，构建概率密度函数。
The probability density function (PDF) is constructed from the time distributions of signal and backgrounds and the relations among time, time uncertainty, mass, and mass difference variables.
核辐射对生物有害，而长时间高水平的本底辐射对生态系统有何影响，人们还知之甚少。
Radiation is harmful to living things, yet the long-term effects of persistently high levels of background radiation on ecosystems are poorly understood.
应用此模型研究了萃取时间、水样中氯仿的本底质量浓度和高效有机吸附膜厚度等对萃取效率的影响。
By this model, the effects of adsorption time, concentration of chloroform in drinking water and film thickness on the adsorption efficiency were discussed.
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