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221.
库车坳陷侏罗系煤成气动力学模拟研究 总被引:1,自引:0,他引:1
应用黄金管—高压釜封闭体系热模拟实验与GC、GC-IRMS分析技术,结合KINETICS专用软件,对库车坳陷侏罗系煤成气进行了动力学模拟研究。库车坳陷侏罗系煤具有高的产气性,在高演化阶段主要产甲烷气;侏罗系煤热解气甲烷碳同位素为-36‰~-25‰,乙烷碳同位素为-28‰~-16‰;甲烷、C2-C5气态烃的生成活化能分别为(47~64k)calm/ol、(55~72k)calm/ol,频率因子各为5.265×1013s-1、5.388×1018s-1。在此基础上,进一步探讨了克拉2气田天然气的成因。研究认为,克拉2气田天然气属阶段捕获的煤成气,主要聚集了5~1Ma时期的天然气,其成熟度Ro分布范围为1.3%~2.5%。 相似文献
222.
Modeling of rainfall-triggered shallow landslide 总被引:5,自引:3,他引:5
By integrating hydrological modeling with the infinite slope stability analysis, a rainfall-triggered shallow landslide model was developed by Iverson (Water Resour Res 36:1897-1910, 2000). In Iverson’s model, the infiltration capacity is assumed to be equivalent to the saturated hydraulic conductivity for finding pressure heads analytically. However, for general infiltration process, the infiltration capacity should vary with time during the period of rain, and the infiltration rate is significantly related to the variable infiltration capacity. To avoid the unrealistically high pressure heads, Iverson employed the beta-line correction by specifying that the simulated pressure heads cannot exceed those given by the beta line. In this study, the suitability of constant infiltration capacity together with the beta-line correction for hydrological modeling and landslide modeling of hillslope subjected to a rainfall is examined. By amending the boundary condition at ground surface of hillslope in Iverson’s model, the modified Iverson’s model with considering general infiltration process is developed to conduct this examination. The results show that the unrealistically high pressure heads from Iverson’s model occur due to the overestimation of infiltration rate induced from the assumption that the infiltration capacity is identical to the saturated hydraulic conductivity. Considering with the general infiltration process, the modified Iverson’s model gives acceptable results. In addition, even though the beta-line correction is applied, the Iverson’s model still produces greater simulated pressure heads and overestimates soil failure potential as compared with the modified Iverson’s model. Therefore, for assessing rainfall-triggered shallow landslide, the use of constant infiltration capacity together with the beta-line correction needs to be replaced by the consideration of general infiltration process. 相似文献
223.
Yang Liu Alfred T. Anderson Colin J. N. Wilson Andrew M. Davis Ian M. Steele 《Contributions to Mineralogy and Petrology》2006,151(1):71-87
Large pyroclastic rhyolites are snapshots of evolving magma bodies, and preserved in their eruptive pyroclasts is a record
of evolution up to the time of eruption. Here we focus on the conditions and processes in the Oruanui magma that erupted at
26.5 ka from Taupo Volcano, New Zealand. The 530 km3 (void-free) of material erupted in the Oruanui event is comparable in size to the Bishop Tuff in California, but differs
in that rhyolitic pumice and glass compositions, although variable, did not change systematically with eruption order. We
measured the concentrations of H2O, CO2 and major and trace elements in zoned phenocrysts and melt inclusions from individual pumice clasts covering the range from
early to late erupted units. We also used cathodoluminescence imaging to infer growth histories of quartz phenocrysts. For
quartz-hosted inclusions, we studied both fully enclosed melt inclusions and reentrants (connecting to host melt through a
small opening). The textures and compositions of inclusions and phenocrysts reflect complex pre-eruptive processes of incomplete
assimilation/partial melting, crystallization differentiation, magma mixing and gas saturation. ‘Restitic’ quartz occurs in
seven of eight pumice clasts studied. Variations in dissolved H2O and CO2 in quartz-hosted melt inclusions reflect gas saturation in the Oruanui magma and crystallization depths of ∼3.5–7 km. Based
on variations of dissolved H2O and CO2 in reentrants, the amount of exsolved gas at the beginning of eruption increased with depth, corresponding to decreasing
density with depth. Pre-eruptive mixing of magma with varying gas content implies variations in magma bulk density that would
have driven convective mixing.
Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users. 相似文献
224.
L.J. Hou M. Liu J.J. Lu S.Y. Xu D.N. Ou Y. Yang D.G. Zheng 《Environmental Geology》2006,49(7):937-945
The influences of exposure to the atmosphere on ammonium cycle in the intertidal surface sediments were in situ studied with
a geochemical approach at a typical station in the Yangtze Estuary during three tidal cycles in September 2003. During an
about 8-h emersion period of each diurnal tide, six high-resolution vertical profiles of adsorbed and dissolved ammonium were
measured. It was observed that both adsorbed and dissolved ammonium generally had an increasing trend in sediment cores during
the exposure. The rate of ammonium regeneration in sediments was estimated using the accumulation amount of ammonium including
adsorbed and soluble fractions during the daytime emersion. The calculation result showed that there was relatively high ammonification
rate (˜500 nmol N cm−3 day−1), which reflected that organic nitrogen in sediments was quickly decomposed with a residence time of ˜52.7 days. Due to the
dramatic temperature difference observed in sediment profiles, free convection was considered an important mechanism of regulating
the efflux of produced ammonium into overlying waters. The total estimated amount of regenerated ammonium was ˜1.35×105 t N year−1 in the intertidal flat of the Yangtze Estuary, which occupied 7.6% of the total inorganic nitrogen annually transported to
the estuarine ecosystem. 相似文献
225.
1 Introduction The Ordos Basin is the second largest sedimentary basin in China. During the last 10 years, a great progress has been achieved in the aspects of tectonic evolution, dynamics process, inner and outer geological processes during Mesozoic-Cen… 相似文献
226.
227.
Geodatabase版本控制原理剖析 总被引:6,自引:0,他引:6
随着地理信息系统的发展及其应用的不断扩大,多用户并发操作、长事务处理以及历史数据回溯管理成为大型空间数据库的基本要求,ESRI在面向对象地理模型(Geodatabase数据模型)中通过版本控制为空间数据库的上述要求提供了有效的解决方案。本文详细分析了Geodatabase版本控制基本原理,为建立、管理大型空间数据库以及研究开发全新面向对象空间数据库管理系统提供参考。 相似文献
228.
基于高分辨率遥感影像分类的地图更新方法 总被引:10,自引:0,他引:10
提出了一种在对遥感影像分类的基础上进行地图更新的方法,讨论了利用高分辨率遥感影像,通过不同空间分辨率和光谱分辨率的影像进行融合,利用合适的高通滤波对影像进行边缘检测.构建一个三层的MLP分类器对影像进行分类,提取城市建筑物与道路信息.并在此分类基础上通过对现有地图的叠加来实现地图的更新。实验结果表明,基于影像融合,利用较少数量的训练样本也能生成具有较高精度的分类图,利用分类结果图进行地图更新能取得令人满意的效果。 相似文献
229.
条带开采煤柱稳定性的试验模拟与数值分析——以山东省济宁市太平煤矿为例 总被引:1,自引:0,他引:1
以山东省济宁市太平煤矿为例,采用煤柱模拟试验和数值分析手段,对薄基岩条带开采时所留设煤柱的应力应变状态、煤柱强度结构及煤柱长期稳定性进行了深入的分析与研究,揭示了煤柱稳定性及煤柱应力分布与条采尺寸、采出率、覆岩特征的相互关系,进行了条带煤柱的稳定性评价,为工程实践提供了理论依据。 相似文献
230.
采用共轭剪节理应力反演方法,恢复了邯郸-峰峰矿区晚古生代以来的3期古构造应力场,进而探讨了煤田构造的演化历史,将其分为4大阶段:①中生代早期近NS向挤压,煤系后期改造初动期;②中生代晚期SE-NW向挤压,奠定煤田构造格架的基础;③中生代末至古近纪NW-SE向拉张,煤田构造格架定型;④新近纪以来近东西向拉张,煤田构造的现代活动. 相似文献