A continuous 200-ka palaeoclimatic record from stalagmite in Tangshan Cave, Nanjing

An oxygen isotope temperature record from 381 to 166 kaB.P. ( 230 Th/ 234 U dating and tuned ages) has been obtained by combining data on the isotopic composition of calcites with that of fluid inclusions trapped in a stalagmite from a limestone cave in which a fossil cranium deposited. Several laminae in microsequence of the stalagmite represent climatic events or shifts. The Nanjing man fossil was older than 381 kaB.P.

基于优化关键参数的重气扩散模型应用

危险化学品储罐一旦发生泄漏事故,将极有可能造成灾难性的事故后果。为了提高重气扩散模型模拟结果的精确性,改进SLAB模型中的扩散系数得到SLAB-D模型,然后基于SLAB-M模型改进扩散系数的算法,建立SLAB-MD模型;随后采用Jack Rabbit II液氯泄漏1,7,9号试验对模型性能进行评估。结果表明,四种模型的性能为SLAB-MD>SLAB-D>SLAB-M>SLAB,其中SLAB-MD模型表现优异,统计性能评估指标接近最优值,平均相对偏差,几何平均偏差,平均相对平方差,几何平均方差和FAC2的值分别为0.27,1.34,0.18,1.24和0.93。利用SLAB-MD模型对三起典型危化品泄漏事故进行模拟分析,预测重气浓度分布、三维浓度曲面等关键信息,并根据保护行动标准值预测事故伤亡范围。这些预测结果可为危险化学物质泄漏的应急救援提供有效的技术指导。