测试了不同水灰比、不同养护龄期水泥石的导热系数，并对比了并联模型、串联模型、Maxwell模型、Mori-Tanaka模型、有效介质理论模型和Self-consistent模型对水泥石导热系数的预测效果。利用分子动力学方法计算了水泥石中各相的导热系数。结果表明：水泥石的导热系数随着养护龄期和水灰比的增大而减小。SC模型适用于不同水灰比和养护龄期水泥石导热系数的计算，其计算结果与试验值的相对误差在0.3%~4.7%之间。Maxwell模型和MT模型可以用于对水灰比较大且养护龄期较长的水泥石的导热系数进行计算。

The environmental perturbation on atoms is a key factor restricting the performance of atomic frequency standards, especially in the long-term scale. In this Letter, we perform a real-time noise distinguish (RTND) to an atomic clock to decrease the uncertainty of the atomic clock beyond the level that is attained by the current controlling method. In RTND, the related parameters of the clock are monitored in real time by using the calibrated sensors, and their effects on the clock frequency are calculated. By subtracting the effects from the error signal, the local oscillator is treated as equivalently locked to the unperturbed atomic levels. In order to perform quantitative tests, we engineer time-varying noise much larger than the intrinsic noise in our fountain atomic clock. By using RTND, the influences of the added noises are detected and subtracted precisely from the error signals before feeding back to the reference oscillator. The result shows that the statistical uncertainty of our fountain clock is improved by an order of magnitude to 2×10?15. Besides, the frequency offset introduced by the noise is also corrected, while the systematic uncertainty is unaffected.