铀尾矿氡析出率的Hurst指数与分形特征

铀尾矿氡的析出是一个重要的环境问题.通过室内实验测定了铀尾矿氡析出率随时间的变化,结果表明尾矿中氡析出率随时间呈现明显的非周期振荡变化.应用R/S方法对所获得的氡析出率时间序列数据进行了分形分析,其整个时间序列数据的Hurst指数为0.83,分维值为1.17.移动Hurst指数在大多数情况下位于0.5-0.8之间,实验后期的Hurst指数部分位于0.5以下,表明铀尾矿氡析出率长期趋势不满足随机游走理论,氡析出率具有长期记忆性,但是短期记忆性不显著.尾矿中氡的析出是一个确定性的混沌动力学过程.

Fractal Characters and Hurst Exponent of Radon Exhalation Rate from Uranium Tailings

The uranium tailings radon exhalation is an important environmental problem.The change of the radon exhalation rate of uranium tailings with the time through laboratory experiments is measured,and the results show that the radon exhalation rate of the tailings change obviously with time in non-periodic oscillations.Applying fractal analysis to the radon exhalation rate time-series data by R/S method,the Hurst exponent of the entire time series data is 0.83,the fractal dimension is 1.17.Mobile Hurst exponent is between 0.5 and 0.8 in most cases.The Hurst exponent of the experiments in the later part are below 0.5.The exhalation rate of uranium tailings radon does not meet the long-term trend of random walk theory,the radon exhalation rate has long-term memory,but the short-term memory is not distinct.The radon exhalation from uranium tailings is a deterministic chaotic dynamics.