多源并发下Mur二阶吸收边界和非分裂递归卷积完全匹配层对比研究

多个激励源无延时发射(多源并发)相同中心频率脉冲会形成平面波束信号,增强数据记录质量。本文通过数值模拟对比分析在多源并发情况下,非分裂递归卷积完全匹配层作为吸收边界条件和Mur二阶吸收边界条件对电磁波的吸收效果。其研究结果表明,传统的Mur二阶吸收边界条件对多源并发、多角度掠射情况下电磁波的吸收效果不佳,在大偏移距下会造成波形畸变和形成虚假反射。而在多源并发情况下采用非分裂递归卷积完全匹配层作为吸收边界条件,将坐标伸缩因子引进时域有限差分算法中。通过傅里叶逆变换将频率域坐标伸缩变换PML方程转换到时域,对电场和磁场值在离散状态下进行递归卷积运算求解。从而避免了直接对卷积进行数值求解的复杂计算,在保证计算准确性的同时,节约了内存空间,提高了计算效率。在不分裂波场情况下,改善了网格截断位置对电磁波的吸收效果。

红沙泉露天煤矿外排土场边坡稳定性研究

外排土场边坡稳定是影响露天煤矿生产安全的重要因素之一,为了分析评价红沙泉露天煤矿外排土场边坡稳定性情况,选取当前条件下的7个典型剖面,分别采用瑞典条分法、简化Bishop法、Janbu法结合岩体力学参数进行稳定性分析,并探索了外排土场高度对边坡稳定性影响。结果表明,当前排土高度条件下外排土场最佳边坡角度为24°,7个典型剖面的稳定系数均高于储备系数要求,随排土场高度增加其边坡角度呈减小趋势,当红沙泉露天煤矿外排土场高度增加至120m时,稳定性系数稍有增大,当增加至160m时,稳定性系数降低,在排土场160m至360m,稳定性系数变化不大,达到临界排土场高度360m时的边坡角度为22°,为红沙泉露天煤矿排土场容量释放提供了参考依据。

River Water Quality Model Based on Remote Sensing Information Methods——A Case Study of Lijing River in Guilin City

River water quality models based on remote sensing information models are superior to pure water quality models because they combine the inevitability and risk of geographical phenomena and can take complex geographical characteristics into account. A water quality model for forecasting COD has been established with remote sensing in- formation modeling methods by monitoring and analyzing water quantity and water quality of the Lijing River reach which flows through a complicated Karst mountain area. This model provides a good tool to predict water quality of complex rivers. It is validated by simulating contaminant concentrations of the study area. The results show that remote sensing information models are suitable for complex geography. It is not only a combined model of inevitability and risk of the geographical phenomena, but also a semi-theoretical and semi-empirical formula, providing a good tool to study organic contaminants in complicated rivers. The coefficients and indices obtained have limited value and the model is not suitable for all situations. Some improvements are required.