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341.
Zhang Zhiyong Xiao Wenjiao Majidifard Mahmoud Reza Zhu Rixiang Wan Bo Ao Songjian Chen Ling Rezaeian Mahnaz Esmaeili Rasoul 《International Journal of Earth Sciences》2017,106(4):1223-1238
International Journal of Earth Sciences - The Zagros Orogen developed as a result of Arabia–Eurasia collision. New in situ detrital zircon U–Pb and Hf isotopic analyses from a Cenozoic... 相似文献
342.
Yuyu Wan Shanghai Du Guangyu Lin Fengjun Zhang Tianfu Xu 《Arabian Journal of Geosciences》2017,10(3):71
This study focused on the target injection layers of deep saline aquifers in the Shiqianfeng Fm. in the Carbon Capture and Sequestration (CCS) Demonstration Projects in the Ordos Basin, northwestern China. The study employed a combination method of experiments and numerical simulation to investigate the dissolution mechanism and impact factors of CO2 in these saline aquifers. The results showed (1) CO2 solubility in different types of water chemistry were shown in ascending order: MgCl2-type water < CaCl2-type water < Na2SO4-type water < NaCl-type water < Na2CO3-type water < distilled water. These results were consistent with the calculated results undertaken by TOUGHREACT with about 5% margin of error. CO2 solubility of Shiqianfeng Fm. saline was 1.05 mol/L; (2) compared with distilled water, the more complex the water’s chemical composition, the greater the increase in HCO3 ?concentration. While the water’s composition was relatively simple, the tested water’s HCO3 ?concentrations were in close accord with the calculated value undertaken by the TOUGHREACT code, and the more complex the water’s composition, the poorer the agreement was, probably due to the complex and unstable HCO3 ? complicating matters when in an aqueous solution system including both tested HCO3 ?concentration and calculated HCO3 ?concentration; (3) the CO2 solubility in the saline at the temperature conditions of 55 °C and 70 °C were 1.17 and 1.02 mol/L. When compared with the calculated value of 1.20 and 1.05 mol/L, they were almost the same with only 1 and 3% margin of error; concentrations of HCO3 ? were 402.73 mg/L (0.007 mol/L) and 385.65 mg/L (0.006 mol/L), while the simulation results were 132.16 mg/L (0.002 mol/L) and 128.52 mg/L (0.002 mol/L). From the contrast between the tested data and the calculated data undertaken by the TOUGHREACT code, it was shown that TOUGHRACT code could better simulate the interaction between saline and CO2 in the dissolution sequestration capacity. Therefore, TOUGHREACT code could be used for the inter-process prediction of CO2 long-term geological storage of CO2; (4) The Ca2+ concentration and SO4 2?concentration in saline water had less effect on the solubility of CO2 and HCO3 ?concentration. In addition, TDS and pH values of saline affected not only the solubility of CO2, but also the conversion of CO2 to HCO3 ? due to that they can affect the activity and acid-base balance. So in fact, we just need to consider that the TDS and pH values are main impact factors in the dissolution sequestration capacity of CO2 geological sequestration in deep saline aquifers. 相似文献
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344.
Xu ZHOU Shengtian YANG Xiaoyan LIU Changming LIU Changsen ZHAO Haigen ZHAO Qiuwen ZHOU Zhiwei WANG 《地理学报(英文版)》2015,25(4):437-450
To control soil erosion and restore the degraded environment in the Loess Plateau, a large number of measures related to soil and water conservation have been employed that have profoundly affected catchment properties. This study constructed three indicators to characterize changes to the catchment slope, proposed both a method for a regression analysis of adjacent images and a sequence model, and applied multisource remotely sensed images and GIS spatial clustering analysis technologies to extract thematic information and comprehensively analyze the catchment change characteristics. The results indicate that the catchment slope properties changed significantly. At catchment scale, the average values of ARC, DVC and ART were 6.43%, 25.57% and 4.30%, respectively. There were six clustering types of catchment slope property changes. The maximum and minimum of the average similarities of the clustering types were 0.992 and 0.935. Each slope control measures had a distinct effect on catchment slope; the dominating factor of each clustering type was identified as: Type 1: D-VC, Type 2: D-VCLU, Type 3: D-LUVC, Type 4: D-TAVC, Type 5: D-TAC and Type 6: D-MFC. Type 5 and Type 1 covered the largest areas, respectively occupying 37.28% and 31.01%. Catchment slope property changes also had distinct types that depended on their geomorphological conditions. These findings provide a useful basis from which to further study catchment slope hydrological and soil erosion processes. 相似文献
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346.
2008年汶川MS8.0地震获得了大量的强震动记录, 为研究反应谱特征参数衰减特性提供了重要的基础资料. 本文对已知场地条件的174个台站的记录进行研究, 计算其加速度反应谱并按照最小二乘分段拟合方法进行标定, 进而拟合了反应谱平台值的衰减关系;对比分析了水平方向与竖直方向反应谱平台值的衰减特性, 提出用“平台值的场地衰减影响系数”来定量研究不同场地类型对反应谱平台值的影响, 用“衰减曲线下降速率”来定量分析不同衰减曲线的衰减速率. 通过计算得出水平向Ⅰ, Ⅱ, Ⅲ类场地的平台值场地衰减影响系数平均值分别为0.5358, 1和1.579, 且Ⅲ类场地的加速度平台值衰减曲线的衰减速率最小. 相似文献
347.
Spatiotemporal characteristics of precipitation and extreme events on the Loess Plateau of China between 1957 and 2009 总被引:1,自引:0,他引:1
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Spatiotemporal trends in precipitation may influence vegetation restoration, and extreme precipitation events profoundly affect soil erosion processes on the Loess Plateau. Daily data collected at 89 meteorological stations in the area between 1957 and 2009 were used to analyze the spatiotemporal trends of precipitation on the Loess Plateau and the return periods of different types of precipitation events classified in the study. Nonparametric methods were employed for temporal analysis, and the Kriging interpolation method was employed for spatial analysis. The results indicate a small decrease in precipitation over the Loess Plateau in last 53 years (although a Mann–Kendall test did not show this decrease to be significant), a southward shift in precipitation isohyets, a slightly delayed rainy season, and prolonged return periods, especially for rainstorm and heavy rainstorm events. Regional responses to global climate change have varied greatly. A slightly increasing trend in precipitation in annual and sub‐annual series, with no obvious shift of isohyets, and an evident decreasing trend in extreme precipitation events were detected in the northwest. In the southeast, correspondingly, a more seriously decreasing trend occurred, with clear shifts of isohyets and a slightly decreasing trend in extreme precipitation events. The result suggests that a negative trend in annual precipitation may have led to decreased soil erosion but an increase in sediment yield during several extreme events. These changes in the precipitation over the Loess Plateau should be noted, and countermeasures should be taken to reduce their adverse impacts on the sustainable development of the region. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
348.
江西相山铀矿田邹—石断裂新解 总被引:1,自引:0,他引:1
邹—石断裂分布在江西相山铀矿田西部,前人认为是一条重要的成矿构造.本次研究发现矿体并不产于邹—石断裂本身,断裂没有控制矿体几何形态,不是矿质直接充填或交代的地质构造单元,不具成矿构造的特点.由于邹石断裂在地形上呈现线性沟谷,遥感影像图上呈现清晰的线性影像,切错了花岗斑岩.构造岩主要是围岩的破碎角砾、构造透镜体和断层泥,以脆性变形为主,温热水与之关系密切,故认为,邹—石断裂具有新构造活动的踪迹,可能形成于新近纪—第四纪,属矿后构造. 相似文献
349.
利用甘肃省80个气象站建站至2012年3-5月的降水量资料, 分析了甘肃省春季降水的基本气候特征; 通过EOF、REOF、小波分析等方法, 对甘肃春季降水的时空特性进行了研究, 用Mann-Kendall检验法检验了甘肃春季降水序列是否存在突变现象. 结果表明, 甘肃春季降水空间分布极不均匀, 其空间分布特征是东南部为多雨区、西北部为少雨区. 甘肃春季降水在第一空间尺度上为全区一致, 在第二空间尺度上可分为2个自然气候区, 在第三空间尺度上可分为7个自然气候区. 从年代际变化来看, 1960年代是近50 a来降水最多的10 a, 1990年代是降水最少的10 a; 甘肃春季降水的年际变率十分显著, 降水最多的年份是最少年份的近5倍. 1961-2012年间甘肃春季降水发生了明显的突变, 1982年出现了一次增多趋势的突变, 1992年出现了一次减少趋势的突变. 5 a的短周期和18~19 a的长周期是其主要周期. 甘肃春季降水偏少(多)年份的500 hPa异常环流形势为极涡弱(强)、中纬度亚洲为一脊一槽型、东亚大槽深(浅)、南支槽浅(深). 相似文献
350.
考虑基础刚度影响的风机梁板式桩筏基础模型试验研究 总被引:2,自引:0,他引:2
梁板式桩筏基础作为新型风机基础,前景广阔,适当优化结构,可节约成本。采用大型室内模型试验,研究了梁板式桩筏基础在不同筏板刚度情况下的受力变形特性,同时讨论了桩土荷载分担比的关系。研究表明,在工作荷载范围内,适当增大筏板刚度,桩平均轴力增加,外圈桩承担的荷载增大,内圈桩的轴力减小,环梁及肋梁弯矩减小,但继续增加刚度,对桩身轴力、环梁弯矩、肋梁弯矩的影响并不大;随着荷载的增大,土体承担的荷载比逐步增大,趋于稳值。随着梁板式基础刚度增加,基础内外差异沉降减少,但是达到一定刚度后再增加刚度对变形影响较小。梁板式基础刚度的变化会影响基底反力分布的均匀性,且存在一个最优刚度,使基础底部反力分布最为均匀,本次试验中12梁的梁板式基础基底反力比6梁和实体基础更均匀。桩基的分布和梁的分布存在相互影响,改变梁的分布会影响桩顶力,而桩基在梁底下又会使梁的应力产生重新分布。研究成果可为设计桩筏基础提供参考依据。 相似文献