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81.
山东半岛蓝色经济区土壤有机碳储量及固碳潜力分析   总被引:1,自引:0,他引:1  
土壤碳储量研究在碳循环和全球变化中具有重要意义,但以往碳储量计算结果受到数据来源的制约。山东省多目标区域地球化学调查采用双层网格化采样和分析,获取了大密度、高精度土壤有机碳数据,为土壤碳库的准确计算奠定了基础。笔者利用这些数据计算了山东半岛蓝色经济区表层(0~20 cm)、中上层(0~100 cm)及全层(0~160 cm)的土壤有机碳(SOC)密度和储量,并对其空间分布特征及固碳潜力进行了研究。结果显示,经济区内3种土壤层次的碳库组成不同,表层SOC储量占总碳(TC)储量的71.67%,随深度增加所占比例逐渐减小,而无机碳(SIC)储量所占比例逐渐增加,全层二者所占比率较为接近:表层SOC储量为132.64 Mt,碳密度为2.06 kg/m2;中上层为458.27 Mt,碳密度为7.11 kg/m2;全层为619.96 Mt,碳密度为9.61 kg/m2。各层SOC密度处于全国偏低水平,且在不同土壤类型、地貌类型、土地利用类型之间有一定差异:褐土土表层SOC密度最高(2.48 kg/m2),风沙土最低(0.91 kg/m2);灌溉水田表层SOC密度最高(3.45 kg/m2),菜地最低(1.61 kg/m2)。表层SOC密度分布总体上呈现为沿海地区低、鲁北平原和胶莱盆地中等、山地丘陵和中低山区偏高的分布格局。从第二次土壤普查和本次多目标调查数据所建立的回归方程分析发现,在今后一定时期内,本区表层土壤总体表现为“碳汇”效应,未来可净增总有机碳(TOC)量60.94 Mt,其中“碳源”量5.07 Mt,“碳汇”量65.97 Mt。  相似文献   
82.
鱼田堡煤矿水文地质特征及深部突水模式分析   总被引:5,自引:1,他引:5  
通过对鱼田堡煤矿各生产水平、开采区域、开采煤层涌水观测资料,以及水质化验、连通试验等资料的分析与研究,查明了该矿深部煤层开采的突水水源及突水通道——浅部与采空区融为一体的“地下水库”及深部K3(4#煤层)开采时在煤层顶板以上发育的采动离层裂隙带,为防治矿井深部突水提供了较为切合实际的水文地质依据。  相似文献   
83.
根据构造环境剪应力值水平区分地震和核爆炸   总被引:5,自引:1,他引:5       下载免费PDF全文
陈培善  成瑾  白彤霞 《地震学报》2001,23(3):246-249
根据地震破裂的断裂力学模式,导出了震源参数与地震发生处的构造环境剪应力值t0之间的函数关系.据此,可以大量计算震源处的构造环境剪应力值或背景应力值.若把核爆炸当作地震来计算,发现核爆炸的t0值平均在20MPa左右,明显地高于同震级地震的t0值.其结果可以作为区分地震与核爆炸的依据.  相似文献   
84.
To stabilise the tunnel faces and slopes in soft clay for the Airport Link construction in Australia, fracture grouting and glass fibre-reinforced plastic (GFRP) soil nails are proposed for the soil improvement as well as ease of handling. The compensation caused by the fracture grouting and the gain in strength due to consolidation as well as the geonail have stabilised the soft clay during construction. Only a small amount of ground settlement during soft clay box-jacking operation is generated so that the railway traffic above the embankment can be maintained without interference. The design method of the fracture grouting ground improvement study for this difficult project is discussed in this paper. Extensive laboratory and field tests were employed to verify the design assumptions and to fine-tune the ground improvement studies. The success of this project in poor ground conditions results from combined efforts of extensive field tests, an improved ground improvement design method and a realistic numerical analysis to assess the unstable/highly stressed zones for the placement of soil reinforcement.  相似文献   
85.
中性大气掩星标准反演技术   总被引:8,自引:3,他引:8  
郭鹏  严豪健  洪振杰  刘敏  黄珹 《天文学报》2005,46(1):96-107
结合JPL和GFZ的中性大气标准反演算法,发展了上海天文台中性大气掩星标准反演算法流程.对CHAMP观测资料进行中性大气反演,并将反演结果与ECMWF(the European Center for Medium Range Weather Forecasting)的预报大气数据进行比较.作为讨论,指出将来的发展方向.  相似文献   
86.
张成  夏露  李英杰  于青春 《地学前缘》2016,23(5):184-192
裂缝既是页岩气的聚集空间,同时也是页岩气的运移通道, 对页岩气成藏起着重要控制作用。裂缝的产状、密度、组合特征等很大程度上决定了页岩气是否具有开发价值。该研究对柴达木盆地东部的13个露头的岩石裂缝进行了野外观测统计,实测裂缝1 000多条,选取了三个具有代表性的页岩露头进行统计分析建模。通过野外观测和室内统计分析发现,工作区页岩裂缝发育有三组(某些地段一组不发育),各组裂缝的方向满足Fisher分布,迹线长度满足对数正态分布。确定了各组裂缝方向、长度的均值和方差,以及各组裂缝的密度,建立了三维裂缝网络模型,绘出了模拟的三维裂缝网络图。裂缝三维模型为圆盘模型,即假设单个裂缝三维空间上具有圆盘形状。建模过程采用了逆建模方法,其基本原则是通过拟合实测的二维露头观测数据,优化裂缝三维大小和密度参数,使模型能够准确再现野外所观测到的实际现象,包括露头面上不同裂缝的数量、密度和长度。该研究对柴达木盆地东部石炭系页岩裂缝描述达到了定量化,为研究页岩中油气运移提供了很好的基础数据。  相似文献   
87.
The subaerial tidal sand area in the northern Jiangsu Province (Subei), stretching from Dongtai towards east with a fan shape, is an early developing stage of radial sand ridges distributed in the South Yellow Sea. Since 5000–6000 a BP, after the Holocene transgression maximum in the northern Jiangsu Province, subaqueous tidal sand bodies were exposed and changed into land gradually. The environmental magnetism analysis shows that subaerial tidal sand strata are formed by the convergent-divergent paleo-tidal current field. The sediment source of tidal sand strata came early from the Changjiang River and late from the Yellow River. Sea floor erosion by tidal currents also served as an important sand source. Drilling cores and ground-penetrating profile show that there exists no probability of sand supplying directly by a large river through the apical area of tidal sand ridges either on land or in the sea. Fluvial deposits supplied the tidal sand bodies by alongshore transportation, which corresponds to the conclusions obtained by the analyses of provenance and paleocurrent field. Project supported by the National Natural Science Foundation of China (Grant Nos. 43236120 and 49676288).  相似文献   
88.
发头裸腹溞休眠卵发育的温度因子分析   总被引:2,自引:0,他引:2  
测定了不同温度下发头裸腹溞(Moina irrasa)体眠卵的孵化时间及孵化率;取最先孵出和过半数孵出的两组数据依莱奥姆积温法则求得种群休眠卵最低临界温度为12.00℃,最低有效积温为441.61℃·h;最低亚致死高温点(即最适温度)为35.16℃,以及最低死亡高温点39.44℃。种群中过半数的临界温度为12.88℃,过半数有效积温为557.10℃·h,过半数的亚致死高温点为35.56℃以及过半数死亡高温点为39.49℃。讨论了这些参数在枝角类集约化培养中休眠卵的有效保存与启用所具有的实践意义。  相似文献   
89.
It is well known that methane hydrate has been identified as an alternative resource due to its massive reserves and clean property. However, hydrate dissociation during oil and gas development (OGD) process in deep water can affect the stability of subsea equipment and formation. Currently, there is a serious lack of studies over quantitative assessment on the effects of hydrate dissociation on wellhead stability. In order to solve this problem, ABAQUS finite element software was used to develop a model and to evaluate the behavior of wellhead caused by hydrate dissociation. The factors that affect the wellhead stability include dissociation range, depth of hydrate formation and mechanical properties of dissociated hydrate region. Based on these, series of simulations were carried out to determine the wellhead displacement. The results revealed that, continuous dissociation of hydrate in homogeneous and isotropic formations can causes the non-linear increment in vertical displacement of wellhead. The displacement of wellhead showed good agreement with the settlement of overlying formations under the same conditions. In addition, the shallower and thicker hydrate formation can aggravate the influence of hydrate dissociation on the wellhead stability. Further, it was observed that with the declining elastic modulus and Poisson’s ratio, the wellhead displacement increases. Hence, these findings not only confirm the effect of hydrate dissociation on the wellhead stability, but also lend support to the actions, such as cooling the drilling fluid, which can reduce the hydrate dissociation range and further make deepwater operations safer and more efficient.  相似文献   
90.
There was an earthquake swarm of two major events of MS6.3 and MS5.8 on the Xianshuihe fault in November, 2014. The two major earthquakes are both strike-slip events with aftershock zone along NW direction.We have analyzed the characteristics of this earthquake sequence. The b value and the h value show the significant variations in different periods before and after the MS5.8earthquake. Based on the data of historical earthquakes, we also illustrated the moderate-strong seismic activity on the Xianshuihe fault. The Kangding earthquake swarm manifests the seismic activity on Xianshuihe fault may be in the late seismic active period. The occurrence of the Kangding earthquake may be an adjustment of the strong earthquakes on the Xianshuihe fault. The Coulomb failure stress changes caused by the historical earthquakes were also given in this article. The results indicate that the earthquake swarm was encouraged by the historical earthquakes since1893, especially by the MS7.5 Kangding earthquake in1955. The Coulomb failure stress changes also shows the subsequent MS5.8 earthquake was triggered by the MS6.3earthquake.  相似文献   
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