【作者】 刘清坤；

【导师】 黄兴法；

【作者基本信息】 中国农业大学 ， 农业机械化工程， 2003， 硕士

【摘要】 本论文首先根据γ射线穿透物体过程中的衰减规律以及水沙液固两相流的特性，用数学的方法从理论上推求了γ射线透射法计算泥沙含量的理论计算公式。大量室内试验结果表明采用γ射线透射法测量泥沙含量完全可行，且测量结果准确可靠，不受土壤类型的影响，是目前现场快速、简便、高精度的非扰动泥沙含量测量方法。 质量吸收系数是决定理论计算公式计算精度的一个重要参数。目前普遍采用单点法来计算吸收系数的值。本文运用数学回归分析的方法，研究了估算此参数的计算公式即多点法。大量室内实测数据验证结果表明单点法和多点法都可以应用于计算质量吸收系数的值，且具有较高的计算精度。多点回归法以大量实验数据为基础上，很大程度上消除随机误差的影响。而单点法物理概念明确，但精度受随机因素影响较大。同时从理论上分析了质量吸收系数变化对泥沙含量测量精度的影响，结果表明质量吸收系数的一定估计误差将引起泥沙含量测量结果的等量误差。 本论文最后详细阐述了γ射线河流泥沙含量和流速自动化监测系统的组成、功能、工作原理以及应用范围。整个系统在中央测控单元的控制下实现河流泥沙含量和流速数据的自动采集、存储、远程传送。此系统可帮助水文工作者更快、更准的获取泥沙含量及流速数据，大大提高水文工作者的工作效率和水文测验仪器的自动化水平。更多还原

【Abstract】 The formula for computing sediment concentration is determined with mathematical method theoretically according to the attenuation law of Y ray and characteristics of mixture of solid and liquid. Many laboratory experiments indicate that using Y ray attenuation method to measure sediment concentration is totally feasible. The measurement result is accurate and reliable and is not affected by the type of soil. Therefore it is a quick and simple method that can measure sediment precisely.In theoretical computation formula the mass absorption coefficient is an important parameter to affect computation precision of sediment concentration. Currently the single-point is used to compute it widely. The computation formula (multi-point method) is studied to estimate its value by mathematical regression analysis. Much experiment data indicates that the single-point method and multi-point can both applied to estimate its value and their precision is very high. A large number of experimental data is used to determine the mass absorption coefficient in the multi-point method so the stochastic errors can be got rid of to a great extent. The specific physical concept is contained in the single-point but its computation precision is affected by the stochastic errors. Its influence on measurement precision of sediment concentration is also analyzed and the result indicates that a specific estimation error will bring about equal error.Finally the constitution, function, principle and application range of an automatic system for monitoring sediment with r ray and velocity of river flow is described in detail. Automatic data collection, memory and remote transmission of sediment concentration and velocity of river flow are realized under control of the industrial computer. Hydrologists can benefit from this system. Their work efficiency and hydrological instrument automation level are advanced greatly.更多还原