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准弹性中子散射(quasi-elastic neutron scattering,QENS)实验是研究水泥老化过程中水动态的一种新颖的实验方法.本文利用老化时间分别为7,14和30 d水泥样品的QENS谱实验数据,通过应用四个高斯项的和的能量分辨函数R(Q,E)代替一个高斯项的能量分辨函数来改进经验扩散模型(empirical diffusion model,EDM),再进行非线性最小二乘拟合.由此导出水泥样品中水动态的相关物理参数:不动水数密度A,自由水指数FWI=B1/(A+B1+B2),洛伦兹函数的半高宽Γ,移动水跳跃之间的平均停留时间τ0及自扩散系数D t,而且可得出更为精准的QENS谱拟合曲线.拟合得到的物理参数可定量描述水泥老化过程中水动态过程,从而为QENS实验在水泥老化过程中水动态研究的应用提供一种合理实用的谱分析方法.
Quasi-elastic neutron scattering (QENS) experiment is a new experimental method to study the water dynamics in the aging process of cement.In this paper, the experimental data of QENS spectra of cement samples with aging time of 7, 14 and 30 d respectively , An empirical diffusion model (EDM) is improved by applying an energy resolution function of the sum of four Gaussian terms, R (Q, E), instead of an energy resolution function of a Gaussian term, followed by a nonlinear least square fitting. The relevant physical parameters of water dynamic in cement samples are deduced as follows: constant water number density A, free water index FWI = B1 / (A + B1 + B2), Lorentz function half height width Γ, moving water jump Average residence time τ0 and self-diffusion coefficient D t, and more accurate QENS spectrum fitting curve can be obtained.The fitting physical parameters can quantitatively describe the water dynamic process of cement aging process, so as QENS experiment in cement aging The application of water dynamic research in the process provides a reasonable and practical spectrum analysis method.