Orbital control on cyclical organic matter accumulation in Early Silurian Longmaxi Formation shales     

Siding Jin  Hucheng Deng  Xing Zhu  Yan Liu  Sibing Liu  Meiyan Fu 《地学前缘(英文版)》2020,(2):533-545

High resolution(939 samples)total organic carbon content(TOC)analyses were conducted on the Shuanghe Section of^152.6 m in the Changning area,Sichuan Basin.The sampling section was divided into two units considering the distinct-different deposit environment and sediments accumulation rate.The lower part(Unit 1)and the peer part(Unit 2)with high resolution sample spacing(0.08–0.4 m)enables the identification of the precession cycle in two sedimentary sequences with distinct different sedimentary accumulation rate.MTM Power spectral analyses on untuned TOC series reveals significant peaks exceeding above the 95%confidence level and shows that both Unit 1 and Unit 2 have recorded Milankovitch cycles of 405 kyr long eccentricity,short eccentricity,obliquity and precession.The floating astronomical time scale(ATS)was constructed on the Shuanghe Section in the Early Silurian(~439.673–444.681 Ma),and which was calibrated by 405 kyr long eccentricity cycles.The total duration of the Wufeng and Longmaxi shales is 5.01 Myr.The floating ATS used for estimating the duration of the graptolite zones and each stage in the study interval.Finally,we postulated two models that could verify the linkage between orbital cycle and organic accumulation.To make sure whether productivity or preservation is the main factor that under long eccentricity control,the phase correlation between the obtained filtered signal and the theoretical orbital solution should be made clear in the further research.  相似文献   

钻井局域网实时监控设备研发          下载免费PDF全文

韩晓玲  闫思江  韩文峰  张圣杰  韩红玲 《探矿工程》2020,47(12):30-35

为实现钻井指挥部对各钻井站点钻采工艺的远程监控，在前期钻井工艺参数自动实时监测的单机研发基础上,本文应用TIA portal软件进行主站从站组网监控研究，实验设备用Siemens1200PLC做主控机，用Siemens200PLC做从站控制机监控钻采现场工艺参数，通过主控机与各从站点组态，实现主控机对从站主从控制。装机后在钻采现场进行了无线网传输实验，实验结果表明:应用互联网通信技术解决无线网断点续传问题，能够实现了钻采实时监控数据短距离传输。  相似文献   

中国省域尺度17部门资本存量的时空特征分析     

刘丽  李宁  张正涛  冯介玲  陈曦  白扣  黄承芳 《地理科学进展》2019,38(4):546-555

随着灾害强度、频率以及承灾体暴露的增加,自然灾害造成的损失日益严重。资本存量作为承灾体的经济暴露指标之一,是灾害损失评估的前提和基础。针对目前中国缺乏省域尺度长时间序列的经济部门分类的资本存量数据基础,论文通过永续盘存法,建立了2003—2015年中国大陆31省17部门的资本存量数据库,并分析其时空特征。结果显示：① 全国总资本存量与灾害直接损失的年际变化均呈增加趋势。省域尺度上,通过相关性分析显示,在99%置信度水平上,两者呈显著正相关(r=0.3)。② 时间上,各省17部门资本存量基本也呈增加趋势,但增速不同。在各部门增速最快的省份中,黑龙江省的居民服务、修理和其他服务业增速最快,增长约454.3倍;其次是青海省的租赁和商务服务业(398.3倍)、江苏省的金融业(295.1倍)、安徽省的科学研究和技术服务业(125.1倍)等。③ 空间上,2015年各省17部门资本存量最多的前4个部门分别是房地产业,工业,交通运输、仓储和邮政业,水利、环境和公共设施管理业,占比均在60%以上;且这4个部门资本存量暴露最多的省份是江苏省和广东省。该结果有助于从时空角度了解各省各部门资本存量暴露情况,为各省灾害风险管理者的防灾减灾工作提供重要的参考价值。  相似文献   

不同空间尺度的山洪灾害风险评价模型对比研究          下载免费PDF全文

田丰  张军  冉有华  刘金鹏  周翼 《干旱区地理》2019,42(3):559-569

以山洪灾害风险评价的多准则决策模型、最大熵模型、信息量模型三种常见模型为研究对象，选取河西走廊和张掖市为地理区划（大中）、市域（小）空间尺度研究区，构建山洪灾害风险评价指标体系，分别完成基于三种模型的两种空间尺度的山洪灾害风险评价制图，基于甘肃省地质灾害调查与区划报告数据从模型验证、空间自相关、精度对比和尺度效应等角度对比分析三个模型应用于不同空间尺度的适应性，并给出优选模型。结果表明：最大熵模型是河西走廊（地理区划）空间尺度上山洪灾害风险评价的优选模型；多准则决策模型不适用于张掖市（市域）空间尺度评价，且三个模型运行结果均没有河西走廊（地理区划）空间尺度上表现良好；三个模型的尺度效应明显，在地理区划空间尺度上应用较良好，缩小至市域空间尺度上模拟结果误差增大；不同空间尺度上，最大熵模型均优于多准则决策模型和信息量模型，适用于地理区划（大中）、市域（小）空间尺度的山洪灾害风险评价。  相似文献   

Fully coupled hydraulic fracture simulation using the improved element partition method     

Shujun Peng  Zhennan Zhang  Jianye Mou  Bing Zhao  Zhiyuan Liu  Jiading Wang 《国际地质力学数值与分析法杂志》2019,43(1):441-460

The improved element partition method (IEPM) is a newly developed fracture simulation approach. IEPM allows a fracture to run across an element without introducing extra degrees of freedom. It can also simulate any number of fractures in a prescribed mesh without remeshing. In this study, the IEPM is extended to hydraulic fracture simulation. First, the seepage and volumetric storage matrix of a cracked element are derived using virtual nodes (the intersection points of a crack with element edges). Subsequently, the fully coupled hydromechanical equation is derived for this cracked element. To eliminate the extra degrees of freedom (virtual nodal quantities), the water pressure and displacement of the virtual nodes are associated with their adjacent nodes through least squares interpolation. Finally, the fully coupled equation in terms of nodal quantities is obtained. The verification cases validate the method. By using this method, the field-scale hydraulic fracturing process is well simulated. The proposed approach is simple and efficient for field-scale hydraulic fracture simulation.  相似文献   

经济地理学制度理论的发展与建构的重要方向     

傅沂  赵子奇 《热带地理》2019,39(5):711-720

在中国制度差异显著与目前区域发展不平衡不充分的现实下,经济地理学与制度相结合的研究显得尤为必要。通过系统地梳理经济地理学与制度的关系发现,经济地理学与制度在历史上存在先分离后融合的情况,并且目前经济地理学与制度研究结合态势不容乐观,制度研究在本体论、方法论、时间维度、空间尺度、研究方法等方面仍然存在不足。通过文献梳理与理论分析,认为经济地理学的制度理论应基于演化经济地理学进行建构,并提出了建构的方向：1）以系统论、层级观为指导,注重构建制度的层级结构;2）以反还原论为基础,寻求方法论的突破;3）借助演化的思想与路径依赖理论,强调时间在制度系统中的作用;4）加强对各空间尺度的制度研究;5）注重工具方法的借鉴与创新。  相似文献   

椭圆度-凹坑双缺陷海底管道局部屈曲特性研究   总被引：2，自引：1，他引：1  

薛陆丰  余杨  余建星  徐立新  高静坤  刘浩 《海洋工程》2018,36(2):92-99

海底管道在制造、埋设以及使用过程中极易产生椭圆度-凹坑双缺陷,双缺陷影响管道局部屈曲,对含椭圆度-凹坑双缺陷海底管道的局部屈曲特性研究十分必要。现行规范中采用等效椭圆度对含椭圆度-凹坑海底管道进行评估,该方法无法准确评估不同缺陷形式的屈曲特性。采用形状系数对含椭圆度-凹坑双缺陷的海底管道进行评估,运用有限元软件ABAQUS进行数值模拟,并进行试验验证。在此基础上对含有不同凹坑深度、不同椭圆度的海底管道进行局部屈曲的数值模拟,计算不同形状椭圆度、含有不同凹坑深度海底管道的形状系数,对其进行敏感性分析。计算结果表明:形状系数对海底管道椭圆度、凹坑深度、径厚比敏感性较强;对凹坑宽度敏感性较弱。  相似文献   

A Pilot‐Scale Diatomite Membrane Bioreactor for Slightly Polluted Surface Water Treatment          下载免费PDF全文

Wen Sun  Cuimei Li  Bingzhi Dong  Huaqiang Chu 《洁净——土壤、空气、水》2018,46(9)

  相似文献   

Multi‐Scale Fuzzy Inference System for Influent Characteristic Prediction of Wastewater Treatment          下载免费PDF全文

Zhiwei Cheng  Xuejiao Li  Yun Bai  Chuan Li 《洁净——土壤、空气、水》2018,46(7)

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Effects of the geometry of two‐dimensional fractures on their hydraulic aperture and on the validity of the local cubic law          下载免费PDF全文

Ahmad Hajjar  Luc Scholtès  Constantin Oltéan  Michel Antoine Buès 《水文研究》2018,32(16):2510-2525

Flow through rough fractures is investigated numerically in order to assess the validity of the local cubic law for different fracture geometries. Two‐dimensional channels with sinusoidal walls having different geometrical properties defined by the aperture, the amplitude, and the wavelength of the walls' corrugations, the corrugations asymmetry, and the phase shift between the two walls are considered to represent different fracture geometries. First, it is analytically shown that the hydraulic aperture clearly deviates from the mean aperture when the walls' roughness, the phase shift, and/or the asymmetry between the fracture walls are relatively high. The continuity and the Navier–Stokes equations are then solved by means of the finite element method and the numerical solutions compared to the theoretical predictions of the local cubic law. Reynolds numbers ranging from 0.066 to 66.66 are investigated so as to focus more particularly on the effect of flow inertial effects on the validity of the local cubic law. For low Reynolds number, typically less than 15, the local cubic law properly describes the fracture flow, especially when the fracture walls have small corrugation amplitudes. For Reynolds numbers higher than 15, the local cubic law is valid under the conditions that the fracture presents a low aspect ratio, small corrugation amplitudes, and a moderate phase lag between its walls.  相似文献