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511.
Feixiang Wu Xinhai Li Zhixing Wang Ling Wu Huajun Guo Xunhui Xiong Xiaoping Zhang Xiaojuan Wang 《International Journal of Mineral Processing》2011,98(1-2):106-112
The hydrolyzed titania residue with mainly precipitated hydrated TiO2 is prepared from mechanically activated Panzhihua ilmenite leached by hydrochloric acid. We use H2O2 as a coordination agent to leach Ti from the hydrolyzed titania residue. The effects of H2O2 to-hydrolyzed titania residue mass ratio, leaching pH value, leaching temperature, leaching time, and H2O2 concentration on leaching of hydrolyzed titania residue by H2O2 are investigated. The recovery of Ti is above 98% under the optimal conditions. XRD shows that the peroxo-titania powder prepared by boiling the aqueous titanium peroxide solution is crystalline anatase phase. A well-crystallized anatase TiO2 and rutile TiO2 can be obtained through calcining at the temperature of 800 and 1000 °C, respectively. EDS shows that the impurities including silicon are enriched in the leaching slag. Little Si is detected as the only impurity in the synthetic TiO2 due to the weak alkaline condition of leaching. 相似文献
512.
Late Jurassic-Early Cretaceous Northern Qaidam Basin, NW China: Implications for the earliest Cretaceous intracontinental tectonism 总被引:4,自引:0,他引:4
Lei Wu Ancheng Xiao Liqun WangZhongyan Shen Suping ZhouYuanzhong Chen Liang Wang Dong LiuJunya Guan 《Cretaceous Research》2011,32(4):552-564
Formation of Mesozoic western China, which was dominated by tectonic amalgamation along its southern margin and associated intracontinental tectonisms, holds a key for interpreting the succedent Cenozoic evolution. This paper presents new data including lithology, sedimentary facies, stratigraphic contact, seismic interpretation and paleo-structures within the Upper Jurassic-Lower Cretaceous strata in the northern Qaidam Basin, NW China. These data all account for a contractional tectonic deformation in the earliest Cretaceous. The South Qilian Shan, according to the sedimentary features and provenance analysis, reactivated and exhumated during the deformation, controlling the deposition of the Lower Cretaceous sequences. A simplified model for the Late Jurassic-Early Cretaceous paleogeography and tectonics of the northern Qaidam Basin is accordingly proposed. The results also support a ∼25° clockwise rotation of the Qaidam Basin since the Early Cretaceous and a more accurate Mesozoic evolution process for the basin. This earliest Cretaceous deformation, associated with the reactivation of the South Qilian Shan at the time, are part of the intracontinental tectonisms in central Asia during the Mesozoic, and probably driven by both the closure of the Mongol-Okhostk Ocean to the north and the collision of the Lhasa and the Qiangtang blocks to the south. 相似文献
513.
Rainfall-induced landslides can cause loss of life and damage to property, infrastructure, and the environment. Rainfall patterns affect the pore-water pressure of unsaturated soil slopes, and are related to the slopes’ stability. Four rainfall patterns were chosen to represent natural rainfall patterns for an examination of rainfall infiltration into soil slopes using numerical models incorporating coupled water infiltration and deformation in unsaturated soils. Our analysis showed that rainfall patterns play a significant role in the distribution of the pore-water pressure in soil slopes, and influence the slope stability. The pore-water pressure profile of soil slopes and the factor of safety are affected by the ratio of rainfall intensity and the coefficient of permeability. The depth and shape of the shallow sliding plane of the landslide is closely related to the rainfall pattern; moreover, the results showed a correlation between the factor of safety of the slope and the rainfall intensity. This relationship can be described by a dimensionless rainfall intensity. The nonlinear relationship can be used to estimate the slope stability resulting from rainfall infiltration when the hydro-mechanical coupling in unsaturated soil slopes is considered. 相似文献
514.
Natural Hazards - Traditionally, fundamental factors of supply and demand were important in understanding oil price dynamics before the financial crisis. These factors, however, are no longer... 相似文献
515.
Urban flood susceptibility analysis using a GIS-based multi-criteria analysis framework 总被引:1,自引:0,他引:1
Natural Hazards - Pluvial flooding is a common type of natural hazard caused by rainfall events with high intensity and short duration, which may lead to substantial property damages,... 相似文献
516.
Yang Zhou Ning Li Wenxiang Wu Haolong Liu Li Wang Guangxu Liu Jidong Wu 《Natural Hazards》2014,74(2):541-554
Significant advancements have been made in examining the relationship between economic development and disaster losses at the global and national scales, but very little research has been done at the sub-national level, especially in China. Based on socioeconomic and disaster impact data from 31 provinces (municipalities, and autonomous regions) in China from 1990 to 2010, ordinary least squares regression was used to determine the relationship between socioeconomic development and effects of natural disasters. Results showed that economic development played a distinct role in mitigating disaster damages in the whole China and its eastern, central and western regions. There existed a U-shaped relationship between economic growth and disaster losses in the whole China and its eastern region, and an inverted-U nonlinearity linkage in its central and western areas. These findings further confirmed the existence of a nonlinear relationship between economic development and disaster losses. Economic growth had played a more important role in mitigating disaster losses in the central region of China than that in the western one. Further investigations demonstrated that as economic develops, there were fewer deaths caused by natural hazards in whole China and all its three regions. The combination of the lower level of education, higher unemployment rate and greater gross dependence ratio has contributed to the increase in death toll caused by natural disasters, but this trend could be partly offset by wealth growth. 相似文献
517.
埋藏条件下碳酸盐岩实验室溶蚀作用模拟的热力学模型与地质勘探方向——以陕甘宁盆地下奥陶统马家沟组第五段为例 总被引:1,自引:0,他引:1
肖林萍 《沉积与特提斯地质》1997,(4)
陕甘宁盆地下奥陶统马家沟组五段为潮坪相碳酸盐岩夹蒸发盐沉积。马五段经历了多期复杂的成岩作用,其中溶蚀作用对马五段影响深刻。首次引用热力学理论对埋藏条件下碳酸盐岩溶蚀作用进行了理论分析和计算。其结果表明碳酸盐岩在埋藏成岩的不同温度压力条件下,酸性介质中溶解反应的吉布斯自由能均为负值,说明反应可自动向方解石、白云石溶解的方向进行,并随着温压的升高溶解的趋势增大,而且白云石溶解的趋势比方解石更大。碳酸盐岩溶蚀作用是受热力学规律支配的自然地质作用。碳酸盐岩溶蚀实验模拟的热力学数学模型对陕甘宁盆地油气田勘探具有重大的理论意义和实际应用价值。 相似文献
518.
519.
我国公路泥石流病害严重,泥石流淤埋公路构建筑物是一类常见的公路泥石流病害类型。泥石流衰减动力学是防治泥石流淤埋病害的重要关键技术,也是泥石流运动学、动力学研究的核心问题之一。本文作者运用泥沙运动力学及流体力学原理,初步建立了泥石流固相颗粒和液相浆体的能量衰减条件,把泥石流衰减模式概化为两类,即能量抑制衰减和能量自由衰减;通过泥石流沉积模型试验,得到了不同粘度泥石流体的沉积扇变化形态,随着泥石流体粘度的增大,沉积扇边缘变陡、扩展范围变小、纵轴线长度减小等结论与实际情况吻合;初步建立了泥石流能量衰减速率计算方法。研究成果为防治公路泥石流病害奠定了基础。 相似文献
520.