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Shh通路介导损伤后反应性星形胶质细胞获得干细胞潜能 预览
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作者 许子宁 李晓红 +2 位作者 叶益超 刘晓银 涂悦 《天津医药》 CAS 北大核心 2019年第7期678-682,I0001共6页
目的探讨Shh信号通路对大脑皮质反应性星形胶质细胞(RAS)获得神经干细胞潜能的影响。方法体外原代培养SD大鼠大脑皮质星形胶质细胞,以肿瘤坏死因子(TNF)-α、白细胞介素(IL)-1α和C1q三种因子诱导炎症型RAS,划痕实验制备创伤型RAS,使用... 目的探讨Shh信号通路对大脑皮质反应性星形胶质细胞(RAS)获得神经干细胞潜能的影响。方法体外原代培养SD大鼠大脑皮质星形胶质细胞,以肿瘤坏死因子(TNF)-α、白细胞介素(IL)-1α和C1q三种因子诱导炎症型RAS,划痕实验制备创伤型RAS,使用免疫荧光染色法观察细胞形态及纯度。实验分为普通星形胶质细胞组(对照组)、炎症组、划痕组(创伤组)。炎症组培养至干预后24h,对照组和划痕组培养至第5天进行免疫荧光染色观察巢蛋白(Nestin)阳性细胞,运用Westernblot技术检测不同损伤模型的细胞中Shh蛋白的表达量。之后各组细胞培养至第7天更换神经干细胞培养基,将前述3组各自再分为激活组(各组细胞更换神经干细胞培养基后添加Shh激活剂SAG)和抑制组(各组细胞更换神经干细胞培养基后添加Shh抑制剂环巴胺)两个亚组,培养14d后采用qRT-PCR检测各亚组RAS源性神经干细胞相关基因的表达量。结果细胞损伤模型中,免疫荧光染色证明各组细胞中划痕组Nestin阳性细胞明显多于炎症组和对照组。Westernblot结果显示2组损伤细胞中划痕组Shh蛋白表达量高于炎症组(P<0.05)。更换神经干细胞培养基后,激活组中2组损伤细胞的干细胞相关基因Nestin、Pax-6、Sox-2、Oct-4和Map-2的表达水平均有所升高,其中由划痕诱导的RAS神经干细胞相关基因Nestin、Pax-6、Sox-2、Oct-4和Map-2的表达水平高于炎症诱导的RAS神经干细胞和普通星形胶质细胞(P<0.01);添加Shh抑制剂后,3组上述基因表达量皆明显降低,但划痕组的表达量仍高于其他2组(P<0.01)。结论在体外,Shh信号通路可以介导损伤后大脑皮质RAS获得干细胞潜能。 展开更多
关键词 星形细胞 基因 反应性星形胶质细胞 SHH SAG 环巴胺 神经干细胞
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考虑导线弧垂的雷电感应电压计算与分析 预览
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作者 刘欣 岳慧清 《华北电力大学学报:自然科学版》 CAS 北大核心 2019年第3期57-65,共9页
为了提高配电线路的安全可靠性并对线路防雷设计提供有价值的参考依据,基于非均匀传输线理论和Agrawal场线耦合模型,实现了一种用于求解非均匀多导体传输线场线耦合模型改进电报方程的单变量时域有限元(FETD)法,通过与双变量FETD法对比... 为了提高配电线路的安全可靠性并对线路防雷设计提供有价值的参考依据,基于非均匀传输线理论和Agrawal场线耦合模型,实现了一种用于求解非均匀多导体传输线场线耦合模型改进电报方程的单变量时域有限元(FETD)法,通过与双变量FETD法对比,验证该方法的正确性。针对典型35kV架空配电线路,计算了不同大地电导率和雷击距离条件下考虑导线弧垂的雷电感应电压,并分析了弧垂对雷电感应电压的影响机理。结果表明实现线路雷电感应电压的准确计算需要计及弧垂的影响。此外,比较了考虑弧垂、电晕和架设地线对雷电感应电压的影响,进一步说明了考虑导线弧垂的必要性。 展开更多
关键词 配电线路 雷电感应电压 单变量时域有限元法 非均匀多导体传输线 弧垂
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Orbital cyclicity in sedimentary sequence and climatic indications of C-O isotopes from Lower Cretaceous in Qingxi Sag,Jiuquan Basin,NW China 预览
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作者 Siding Jin Haiyang Cao +2 位作者 Hua Wang Michael Wagreich Sylvain Richoz 《地学前缘:英文版》 CAS CSCD 2019年第2期467-479,共13页
Sedimentary deposits of the Lower Cretaceous Xiagou Formation form the most significant potential hydrocarbon reservoirs in the Qingxi Sag,Jiuquan Basin(NW China).Zircon U-Pb ages of the dated basalts at the top of th... Sedimentary deposits of the Lower Cretaceous Xiagou Formation form the most significant potential hydrocarbon reservoirs in the Qingxi Sag,Jiuquan Basin(NW China).Zircon U-Pb ages of the dated basalts at the top of the Xiagou Formation give an isochron age of 115.6 Ma,and the sedimentation interval of the Xiagou Formation was speculated to range from about 125/124 Ma to 115 Ma based on paleontological research and stratigraphic correlation analysis.Here we use GR logging data as a palaeoenvironmental and palaeoclimatic proxy to conduct a detailed cyclostratigraphic study of five selected wells.Power spectra,evolutionary fast Fourier transformation and wavelet analysis all reveal significant sedimentary cycles in the Xiagou Formation.The ratios of cycle wavelengths in these stratigraphic units are 33.82 m:7.91 m:3.06 m:1.79 m,which is similar to the ratio of orbital targets of 20:5:2:1.The ratio of 20:5:2:1 is interpreted as Milankovitch cycles of 405 kyr long eccentricity,100 kyr short eccentricity,37 kyr obliquity,and 22 kyr precession cycles respectively.A high-resolution astronomical time scale is constructed by tuning the stratigraphy into target curves of orbital cycles respectively.Based on the astronomical time scale,the absolute ages of 55 samples were estimated,which are used for subsequent stable carbon and oxygen isotope stratigraphy analysis.The analysis results of the five studied wells in the Qingxi Sag indicate:(1)a negative trend ofδ13C values upwards in the Xiagou Formation,and(2)negativeδ18O values with a positive trend upwards.Both relatively heavy values and pronounced covariances ofδ13C values andδ18O values indicate an arid-evaporationcontrolled climate during the sedimentary period of the Lower Cretaceous Xiagou Formation,Qingxi Sag,Jiuquan Basin.Moreover,positive covariances of SQK1g2t3 indicate extremely high temperature,and negative covariances of SQK1g1 indicate a relatively low temperature. 展开更多
关键词 Jiuquan Basin Qingxi SAG Xiagou Formation ORBITAL CYCLICITY Stable ISOTOPE
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Stable carbon and hydrogen isotopic characteristics of natural gas from Taibei sag, Turpan-Hami Basin, NW China 预览
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作者 NI Yunyan LIAO Fengrong +3 位作者 GONG Deyu JIAO Lixin GAO Jinliang YAO Limiao 《石油勘探与开发:英文版》 2019年第3期531-542,共12页
Turpan-Hami Basin is a major petroliferous basin in China. To date the natural gas exploration is concentrated in the Taibei sag. The origin and source of natural gas in the Taibei sag has long been controversial. To ... Turpan-Hami Basin is a major petroliferous basin in China. To date the natural gas exploration is concentrated in the Taibei sag. The origin and source of natural gas in the Taibei sag has long been controversial. To further investigate the origin and source of the natural gas in the Taibei sag, combined with previous studies and the local geological backgrounds, this study collected 23 gas samples from the Baka, Qiuling, Shanshan and Wenmi oil fields in the Taibei sag and analyzed the sample composition, stable carbon and hydrogen isotopes of all the gas samples. The results show that, gases from the four oil fields in the Taibei sag are dominated by hydrocarbon gas and belong to wet gas. Methane accounts for 65.84% to 97.94%, the content of heavy hydrocarbon (C2-5) can be up to 34.98%, while the content of nonhydrocarbon (CO2, N2) is trace. The δ13C1 value is –44.9‰ to –40.4‰,δ13C2 is –28.2‰ to –24.9‰,δ13C3 is –27.1‰ to –18.0‰ and δ13C4 is –26.7‰ to –22.1;while the variation of δD1 is not significant from –272‰ to –252‰,δD2 is –236‰ to –200‰ and δD3 is –222‰ to –174‰. Methane and its homologues (C2-5) are characterized by normal stable carbon and hydrogen isotopic distribution pattern, i.e., with the increase of carbon number, methane and its homologues become more and more enriched in 13C or D (δ13C1<δ13C2<δ13C3<δ13C4<δ13C5,δD1<δD2<δD3), which is consistent with the carbon and hydrogen isotopic features of typical thermogenic gas. All these results show that the natural gases in the four oil fields are coal-derived gas with low maturity (Ro averaged at 0.7%), and are sourced from the Middle-Lower Jurassic coal measure. The hydrogen isotopic data of natural gas are affected by both thermal maturity and the water medium of the environment where source rocks are formed. The hydrogen isotopic data indicate that the source rocks are formed in terrestrial limnetic facies with freshwater. Natural gases from Well Ba23 and Well Ke19 experienced biodeg 展开更多
关键词 Turpan-Hami Basin Taibei SAG Jurassic carbon ISOTOPE HYDROGEN ISOTOPE coal-derived GAS low MATURE GAS
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Lithofacies paleogeography and exploration significance of Sinian Doushantuo depositional stage in the middle-upper Yangtze region, Sichuan Basin, SW China 预览
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作者 WANG Zecheng LIU Jingjiang +7 位作者 JIANG Hua HUANG Shipeng WANG Kun XU Zhengyu JIANG Qingchun SHI Shuyuan REN Mengyi WANG Tianyu 《石油勘探与开发:英文版》 2019年第1期41-53,共13页
In recent years, natural gas exploration in the Sinian Dengying Formation and shale gas exploration in Doushantuo Formation have made major breakthroughs in the Sichuan Basin and its adjacent areas. However, the sedim... In recent years, natural gas exploration in the Sinian Dengying Formation and shale gas exploration in Doushantuo Formation have made major breakthroughs in the Sichuan Basin and its adjacent areas. However, the sedimentary background of the Doushantuo Formation hasn’t been studied systematically. The lithofacies paleogeographic pattern, sedimentary environment, sedimentary evolution and distribution of source rocks during the depositional stage of Doushantuo Formation were systematically analyzed by using a large amount of outcrop data, and a small amount of drilling and seismic data.(1) The sedimentary sequence and stratigraphic distribution of the Sinian Doushantuo Formation in the middle-upper Yangtze region were controlled by paleouplifts and marginal sags. The Doushantuo Formation in the paleouplift region was overlayed with thin thickness, including shore facies, mixed continental shelf facies and atypical carbonate platform facies. The marginal sag had complete strata and large thickness, and developed deep water shelf facies and restricted basin facies.(2) The Doushantuo Formation is divided into four members from bottom to top, and the sedimentary sequence is a complete sedimentary cycle of transgression–high position–regression. The first member is atypical carbonate gentle slope deposit in the early stage of the transgression, the second member is shore-mixed shelf deposit in the extensive transgression period, and the third member is atypical restricted–open sea platform deposit of the high position of the transgression.(3) The second member has organic-rich black shale developed with stable distribution and large thickness, which is an important source rock interval and major shale gas interval. The third member is characterized by microbial carbonate rock and has good storage conditions which is conducive to the accumulation of natural gas, phosphate and other mineral resources, so it is a new area worthy of attention. The Qinling trough and western Hubei trough are favorable areas for expl 展开更多
关键词 SINIAN Doushantuo Formation lithofacies PALEOGEOGRAPHY Sichuan Basin paleouplift MARGINAL sag carbonate platform black shale source rock
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Present Terrestrial Heat Flow Measurements of the Geothermal Fields in the Chagan Sag of the YingenEjinaqi Basin,Inner Mongolia,China 预览
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作者 FENG Renpeng ZUO Yinhui +4 位作者 YANG Meihua ZHANG Jiong LIU Zhi ZHOU Yongshui HAO Qingqing 《地质学报:英文版》 SCIE CAS CSCD 2019年第2期283-296,共14页
Owing to the lack o f terrestrial heat flow data, studying lithospheric thermal structure and geodynamics of the Yingen-Ejinaqi Basin in Inner Mongolia is limited. In this paper, the terrestrial heat flow o f the Chag... Owing to the lack o f terrestrial heat flow data, studying lithospheric thermal structure and geodynamics of the Yingen-Ejinaqi Basin in Inner Mongolia is limited. In this paper, the terrestrial heat flow o f the Chagan sag in the YingenEjinaqi Basin were calculated by 193 system steady-state temperature measurements of 4 wells, and newly measuring 62 rock thermal conductivity and 20 heat production rate data on basis o f the original 107 rock thermal conductivity and 70 heat production data. The results show that the average thermal conductivity and heat production rate are 2.11 ±0.28 W/(m.K) and2.42±0.25 nW/m~3 in the Lower Cretaceous o f the Chagan sag. The average geothermal gradient from the Lower Suhongtu 2 Formation to the Suhongtu 1 Fonnation is 37.6 °C/km, and that o f the Bayingebi 2 Formation is 27.4 °C/km. Meanwhile, the average terrestrial heat flow in the Chagan sag is 70.6 mW/m~2. On the above results, it is clear that there is an obvious negative correlation between the thermal conductivity o f the stratum and its geothermal gradient. Moreover, it reveals that there is a geothermal state between tectonically stable and active areas. This work may provide geothermal parameters for further research o f lithospheric thermal structure and geodynamics in the Chagan sag. 展开更多
关键词 thermophysical parameters GEOTHERMAL gradient TERRESTRIAL heat flow CHAGAN SAG Yingen-Ejinaqi BASIN
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Characteristics of boundary fault systems and its hydrocarbon controlling on hydrocarbon accumulation in Awati Sag,Tarim Basin,China 预览
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作者 Zhong-kai Bai Xiu-xiang Lu +7 位作者 Zong-xu Song Hai-jun Qiu Xin-gui Zhou Yong-jin Gao Ying-min Qi Li-chun Zhu Xiao-tao Fu Yuan-yuan Zhou 《中国地质(英文)》 2019年第1期94-107,共14页
Based on the interpretation of two-dimensional seismic data, this paper analyzes the characteristics of three boundary fault systems including the Shajingzi fault, the Aqia fault and the Tumuxiuke fault around the Awa... Based on the interpretation of two-dimensional seismic data, this paper analyzes the characteristics of three boundary fault systems including the Shajingzi fault, the Aqia fault and the Tumuxiuke fault around the Awati sag of the Tarim Basin, and studies its controlling on hydrocarbon accumulation. Neotectonic movement is ubiquitous in oil and gas bearing basins in China, such as Neogene intense activities of large boundary thrusting faults of the Awati sag: Shajingzi fault, Aqia fault and Tumuxiuke fault. Based on a large number of seismic data, it is showed that they have section wise characteristics in the direction of fault strike, and active periods and associated structures formed of different sections are different. Usually, large anticlinal structures are formed in the upper wall, and faulted anticline controlled by companion faults are formed in the bottom wall. Large faults cut the strata from Cambrian up to Neogene. For the anticline in the upper wall, fault activities caused by neotectonic movement played a destructive role in hydrocarbon accumulation, thus the preservation condition is critical for reservoir formation. In this sense, attention should be paid to formations in the upper walls of Aqia fault and Tumuxiuke fault under the Cambrian salt bed, whose plastic deformation could help to heal faults. Companion faults in the bottom wall cut down to the Cambrian and up to the Triassic serving as the pathway for hydrocarbon migration, and associated structures in the bottom wall are noteworthy exploration targets. 展开更多
关键词 NEOTECTONIC movement BOUNDARY fault Reservoir forming control Awati SAG TARIM Basin
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浅谈柴油机的船上安装和校中 预览
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作者 王辉帅 《广东造船》 2019年第2期77-79,55共4页
本文较详细地介绍了船舶柴油机吊装机舱后的安装和校中,对业界具有一定的指导和参考作用。
关键词 船舶柴油机 开口 偏移 拐档差
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凹陷露天矿山排水方案优化研究 预览
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作者 董菊美 字成周 《中国矿业》 北大核心 2019年第A01期340-342,共3页
我国大部分露天矿山基本进入深部开采阶段,项目投入成本逐渐增高,且近几年地表征地困难,采场空间逐渐缩小,所以优化露天开采工艺和露天开采系统,最大限度降低成本、提高效率,成为许多矿山投入生产建设首先考虑的问题。本文分析了凹陷露... 我国大部分露天矿山基本进入深部开采阶段,项目投入成本逐渐增高,且近几年地表征地困难,采场空间逐渐缩小,所以优化露天开采工艺和露天开采系统,最大限度降低成本、提高效率,成为许多矿山投入生产建设首先考虑的问题。本文分析了凹陷露天矿山开采排水方面存在的难题,通过实例探讨了凹陷露天开采排水系统优化的必要性和可行性,也为类似矿山排水提供借鉴。 展开更多
关键词 凹陷 露天矿山 抽排水 折返-螺旋式
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尼尔森选矿机在大型镍铜矿半自磨回路中的应用 预览
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作者 刘志伟 张玮昌 《有色金属:选矿部分》 CAS 北大核心 2019年第2期87-90,共4页
金川镍铜矿石中富含贵金属矿物,在常规磨矿流程中进行了贵金属尼尔森重选回收的工业试验。依据试验情况和贵金属矿物的性质,设计了尼尔森选矿机在半自磨回路中的应用流程,并在金川大型镍铜矿半自磨回路中成功应用,在原矿贵金属品位Au 0.... 金川镍铜矿石中富含贵金属矿物,在常规磨矿流程中进行了贵金属尼尔森重选回收的工业试验。依据试验情况和贵金属矿物的性质,设计了尼尔森选矿机在半自磨回路中的应用流程,并在金川大型镍铜矿半自磨回路中成功应用,在原矿贵金属品位Au 0.11g/t、Pt 0.19g/t的情况下,得到了品位Au 60.95g/t、Pt 218g/t,回收率Au 29.92%,Pt 61.96%的贵金属精矿,取得了良好的选别指标。 展开更多
关键词 尼尔森选矿机 半自磨 贵金属
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纳米改性对含碳化物等温淬火球墨铸铁磨球金相组织的影响 预览
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作者 张婷 魏明安 陈经华 《矿冶》 CAS 2019年第3期84-88,共5页
针对大型半自磨机现用磨球磨耗高、破碎率高的现状,研究了纳米改性和高温预处理对含碳化物的等温淬火球墨铸铁磨球金相组织的影响。实验结果表明:随着纳米改性剂加入量的增加,石墨球趋向圆整化、细小化和分布均匀化;碳化物趋向细小化和... 针对大型半自磨机现用磨球磨耗高、破碎率高的现状,研究了纳米改性和高温预处理对含碳化物的等温淬火球墨铸铁磨球金相组织的影响。实验结果表明:随着纳米改性剂加入量的增加,石墨球趋向圆整化、细小化和分布均匀化;碳化物趋向细小化和分布均匀化;高温预处理使碳化物数量减少,边界钝化,短杆状向球形过渡。优化后的金相组织细小均匀,对提高磨球的耐磨性及抗破碎能力极为有利。 展开更多
关键词 半自磨 磨球 纳米改性 球墨铸铁 金相组织
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赴美参加ISO/TC22 SAG会议及ISO/TC22第41次全体会议情况的报告
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作者 郭淼 《中国汽车》 2019年第8期27-29,共3页
2019年6月19日至21日,ISO/TC22 SAG(国际标准化组织道路车辆技术委员会战略咨询工作组)会议及ISO/TC22第41次全体会议在美国特洛伊市召开。来自中国、日本、美国、韩国、法国、德国、伊拉克等ISO/TC22成员及ISO/TC204代表共计40余人参... 2019年6月19日至21日,ISO/TC22 SAG(国际标准化组织道路车辆技术委员会战略咨询工作组)会议及ISO/TC22第41次全体会议在美国特洛伊市召开。来自中国、日本、美国、韩国、法国、德国、伊拉克等ISO/TC22成员及ISO/TC204代表共计40余人参加了上述会议。中国代表团由国家市场监督管理总局徐翔及中国汽车技术研究中心有限公司技术人员组成。现将会议有关情况报告如下: 展开更多
关键词 ISO/TC22 SAG 意大利 TC 中国汽车技术研究中心 标准化工作 工作组 WG 标准化组织 国际标准化
Origin and migration model of natural gas in L gas field, eastern slope of Yinggehai Sag, China 预览
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作者 YANG Jihai HUANG Baojia 《石油勘探与开发:英文版》 2019年第3期471-481,共11页
Based on the chemical and stable carbon isotopic composition of natural gas and light hydrocarbons, along with regional geological data, the genetic type, origin and migration of natural gases in the L lithologic gas ... Based on the chemical and stable carbon isotopic composition of natural gas and light hydrocarbons, along with regional geological data, the genetic type, origin and migration of natural gases in the L lithologic gas field, the eastern slope of Yinggehai Sag were investigated. The results show that these gases have a considerable variation in chemical composition, with 33.6%–91.5% hydrocarbon, 0.5%-62.2% CO2, and dryness coefficients ranging from 0.94 to 0.99. The alkane gases are characterized by δ13C1 values of -40.71‰--27.40‰,δ13C2 values of –27.27‰– –20.26‰, and the isoparaffin contents accounting for 55%–73% of the total C5–C7 light hydrocarbons. These data indicate that the natural gases belong to the coal-type gas and are mainly derived from the Miocene terrigenous organic-rich source rocks. When the CO2 contents are greater than 10%, the δ13CCO2 values are –9.04‰ to – 0.95‰ and the associated helium has a 3He/4He value of 7.78×10^–8, suggesting that the CO2 here is crustal origin and inorganic and mainly sourced from the thermal decomposition of calcareous mudstone and carbonate in deep strata. The gas migrated in three ways, i.e., migration of gas from the Miocene source rock to the reservoirs nearby;vertical migration of highly mature gas from deeper Meishan and Sanya Formations source rock through concealed faults;and lateral migration along permeable sandbodies. The relatively large pressure difference between the “source” and “reservoir” is the key driving force for the vertical and lateral migration of gas. Short-distance migration and effective “source - reservoir” match control the gas distribution. 展开更多
关键词 EASTERN SLOPE of Yinggehai SAG L lithologic GAS field coal-type GAS crustal inorganic CO2 gas-source correlation MIGRATION model
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打造受业界尊敬且具有崇公信力的第三方检测机构 预览
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作者 SAG中检联 《食品安全导刊》 2019年第10期53-55,共3页
企业简介中检联检测有限公司(以下简称“SAG中检联”)成立于2011年,注册资金5000万元人民币,总部位于广东省深圳市,并先后在全国设立了北京、山西、湖北、广西、广州等20余家子公司和办事处,是国内专业的第三方食品检测、环境检测、公... 企业简介中检联检测有限公司(以下简称“SAG中检联”)成立于2011年,注册资金5000万元人民币,总部位于广东省深圳市,并先后在全国设立了北京、山西、湖北、广西、广州等20余家子公司和办事处,是国内专业的第三方食品检测、环境检测、公共场所卫生安全解决方案提供商。 展开更多
关键词 食品检测 公信力 环境检测 卫生安全 公共场所 SAG 人民币 深圳市
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山坡条件下的考虑弧垂高压线附近的电场计算
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作者 高阳 孙成勋 +1 位作者 朱宝余 赵昕 《数学的实践与认识》 北大核心 2019年第3期127-134,共8页
在考虑山坡及电缆之间有夹角的条件下,提供一种考虑高压输电线的弧垂因素,可实现对不在同一平面上的高压输电线附近任意一点的电场强度计算的山坡上高压输电线附近电场强度的测算方法,建立三维数学模型预测其对作业场所个体的影响程度... 在考虑山坡及电缆之间有夹角的条件下,提供一种考虑高压输电线的弧垂因素,可实现对不在同一平面上的高压输电线附近任意一点的电场强度计算的山坡上高压输电线附近电场强度的测算方法,建立三维数学模型预测其对作业场所个体的影响程度和范围,阐明高压输电线路附近产生的工频电场的分布规律.克服现有计算方法的不足,通过建立标准坐标系,利用坐标变换实现不在同一平面上的高压输电线对空间中任意一点电场强度的测算,考虑了高压输电线的弧垂对空间中任意一点电场强度的影响,减小了模型计算误差,提高了测算精确性. 展开更多
关键词 高压线 工频电场 弧垂 镜像法 山坡
Miocene paleoenvironmental evolution based on benthic foraminiferal assemblages in the Lufeng Sag, northern South China Sea 预览
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作者 Liyuan Xue Xuan Ding +1 位作者 Renjie Pei Xiaoqiao Wan 《海洋学报:英文版》 SCIE CAS CSCD 2019年第3期124-137,共14页
The Miocene epoch marks the most crucial period during the Cenozoic cooling trend, characterized by the Middle Miocene Climatic Optimum(MMCO) and a series of short–lived cooling events(Miocene isotope events).To unde... The Miocene epoch marks the most crucial period during the Cenozoic cooling trend, characterized by the Middle Miocene Climatic Optimum(MMCO) and a series of short–lived cooling events(Miocene isotope events).To understand the paleoenvironmental evolution along the shallow water shelf in the South China Sea during the Miocene, the benthic foraminiferal assemblage and total organic carbon content(TOC) were analyzed at Hole LF14 located in the Lufeng Sag, northern South China Sea. Three benthic foraminiferal assemblages(e.g., the Uvigerina spp. assemblage, the Cibicides spp. assemblage, and the Cibicidoides spp. assemblage), corresponding to different watermass conditions, were recognized based on Q–mode factor analysis. Early studies suggested that Hole LF14 was deposited under semienclosed bay, middle to outer shelf or even upper bathyal environment during ~18.7–4.53 Ma. The dominant Uvigerina spp. assemblage was characterized by low diversity and shallow infaunal to infaunal species, indicating a warm, low–oxygenation and eutrophic conditions since the Early Miocene to MMCO(~18.7–14.24 Ma). An abrupt sea level drop and significant faunal changes were recorded during 14.24–13.41 Ma, suggesting development of the East Antarctic Ice Sheets, which resulted in a drop of sea level and change in benthic foraminiferal assemblages along the shallow water shelf. Beyond the Uvigerina spp.assemblage, the Cibicides spp. assemblage became important during the middle–late Middle Miocene(14.24–11.54 Ma). This assemblage was dominated by epifaunal species with relative high diversity, suggesting high–energy, high–oxygenation and oligotrophic conditions with episodic supply of organic food. The dominant Cibicidoides spp. assemblage with high diversity, indicates a mesotrophic conditions with relative high–oxygen content during the Late Miocene to Pliocene(11.54–4.53 Ma). The appearance and continuous occurrence of Ammonia spp. and Pseudorotalia spp. since 10.02 Ma, may reflect the influence of the Kuroshio 展开更多
关键词 South China Sea Lufeng SAG MIOCENE BENTHIC foraminiferal assemblage total organic carbon shelf PALEOENVIRONMENT
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一种测量斜拉桥拉索索力新方法——垂度法 预览
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作者 葛俊颖 苏木标 李文平 《中国铁道科学》 CSCD 北大核心 2018年第4期63-70,共8页
考虑拉索弯曲刚度、索端安装减振装置以及几何非线性等因素的影响,采用有限元软件ANSYS分析某斜拉桥拉索索力与垂度的关系。结果表明:当斜拉索索力较大(垂度较小)时,离开其锚固位置和阻尼减振装置一定距离,从拉索中部任意选取一段适... 考虑拉索弯曲刚度、索端安装减振装置以及几何非线性等因素的影响,采用有限元软件ANSYS分析某斜拉桥拉索索力与垂度的关系。结果表明:当斜拉索索力较大(垂度较小)时,离开其锚固位置和阻尼减振装置一定距离,从拉索中部任意选取一段适当长度拉索的索力与垂度之间存在确定的函数关系,且这种关系几乎不受斜拉索本身的弯曲刚度和两端支承条件的影响。据此提出通过测量斜拉索中部某索段的垂度确定索力的方法——垂度法。该方法依据测量出的所选索段的倾角、弦长和最大垂度,按推导的公式计算所选索段的平均索力,根据每延长米的索力差和索段的位置确定整个拉索的索力。模型试验结果表明,用垂度法测得的索力误差在2%以下。 展开更多
关键词 斜拉桥 拉索 垂度 索力 测试方法 垂度法
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Petroleum geology controlled by extensive detachment thinning of continental margin crust: A case study of Baiyun sag in the deep-water area of northern South China Sea 预览
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作者 PANG Xiong REN Jianye +3 位作者 ZHENG Jinyun LIU Jun YU Peng LIU Baojun 《石油勘探与开发:英文版》 2018年第1期29-42,共14页
The relationships between crustal stretching and thinning,basin structure and petroleum geology in Baiyun deep-water area were analyzed using large area 3D seismic,gravity,magnetic,ocean bottom seismic(OBS),deep-water... The relationships between crustal stretching and thinning,basin structure and petroleum geology in Baiyun deep-water area were analyzed using large area 3D seismic,gravity,magnetic,ocean bottom seismic(OBS),deep-water exploration wells and integrated ocean drilling program(IODP).During the early syn-rifting period,deep-water area was a half-graben controlled by high angle faults influenced by the brittle extension of upper crust.In the mid syn-rifting period,this area was a broad-deep fault depression controlled by detachment faults undergone brittle-ductile deformation and differentiated extension in the crust.In the late syn-rifting period,this area experienced fault-sag transition due to saucer-shaped rheology change dominated by crustal ductile deformation.A broad-deep fault depression controlled by the large detachment faults penetrating through the crust is an important feature of deep-water basin.The study suggests that the broad-deep Baiyun sag provides great accommodation space for the development of massive deltaic-lacustrine deposition system and hydrocarbon source rocks.The differentiated lithospheric thinning also resulted in the different thermal subsidence during post-rifting period,and then controlled the development of continental shelf break and deep-water reservoir sedimentary environment.The high heat flow background caused by the strong thinning of lithosphere and the rise of mantle source resulted in particularities in the reservoir diagenesis,hydrocarbon generation process and accumulation of deep-water area in northern South China Sea. 展开更多
关键词 northern South China Sea Zhujiangkou Basin Baiyun sag DEEP-WATER area CONTINENTAL margin CRUST DETACHMENT FAULT broad-deep FAULT depression CONTINENTAL shelf break petroleum geology
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Diagenesis-porosity evolution and “sweet spot” distribution of low permeability reservoirs: A case study from Oligocene Zhuhai Formation in Wenchang A sag, Pear River Mouth Basin, northern South China Sea 预览
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作者 YOU Li XU Shouli +3 位作者 LI Cai ZHANG Yingzhao ZHAO Zhanjie ZHU Peiyuan 《石油勘探与开发:英文版》 2018年第2期251-263,共13页
The characteristics of low permeability reservoirs and distribution of sweet spots in the Oligocene Zhuhai Formation of Wenchang A sag, Pearl River Basin were investigated by core observation and thin section analysis... The characteristics of low permeability reservoirs and distribution of sweet spots in the Oligocene Zhuhai Formation of Wenchang A sag, Pearl River Basin were investigated by core observation and thin section analysis. The study results show that there develop the fine, medium and coarse sandstone reservoirs of tidal flat–fan delta facies, which are of mostly low permeability and locally medium permeability. There are two kinds of pore evolution patterns: oil charging first and densification later, the reservoirs featuring this pattern are mainly in the third member of Zhuhai Formation between the south fault zone and the sixth fault zone, and the pattern of densification first and gas charging later is widespread across the study area. Strong compaction and local calcium cementation are the key factors causing low permeability of the reservoirs in the Zhuhai Formation. Thick and coarse grain sand sedimentary body is the precondition to form 'sweet spot' reservoirs. Weak compaction and cementation, dissolution, early hydrocarbon filling and authigenic chlorite coating are the main factors controlling formation of 'sweet spot' reservoir. It is predicted that there develop between the south fault and sixth fault zones the Class Ⅰ 'sweet spot' in medium compaction zone, Class Ⅱ 'sweet spot' in nearly strong compaction zone, Class Ⅲ 'sweet spot' reservoir in the nearly strong to strong compaction zone with oil charging at early stage, and Class IV 'sweet spot' reservoir in the strong compaction and authigenic chlorite coating protection zone in the sixth fault zone. 展开更多
关键词 low permeability reservoir pore evolution hydrocarbon charging 'sweet spot' DISTRIBUTION Zhuhai Formation OLIGOCENE Wenchang A SAG northern South China Sea
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Formation mechanisms of good-quality clastic reservoirs in deep formations in rifted basins: A case study of Raoyang sag in Bohai Bay Basin, East China 预览
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作者 JIN Fengming ZHANG Kaixun +4 位作者 WANG Quan NIU Xinjie YU Zuogang BAI Guoping ZHAO Xuan 《石油勘探与开发:英文版》 2018年第2期264-272,共9页
In order to reveal the development mechanism of high-quality clastic rock reservoir, the basic characteristics of Sha-3 Member of the Shahejie Formation in the Raoyang sag, Bohai Bay Basin, are analyzed based on cores... In order to reveal the development mechanism of high-quality clastic rock reservoir, the basic characteristics of Sha-3 Member of the Shahejie Formation in the Raoyang sag, Bohai Bay Basin, are analyzed based on cores observation, thin-sections and SEM images, and petrophysical properties measurements as well. It is found that high-mature composition and texture, early oil charging, and dissolution are the main factors controlling the formation and preservation of pores in deep reservoirs. Compaction is the major factor destructing pores, whereas formation overpressure is conducive to the preservation of original pores, high compositional and medium textural maturity can enhance the resistance capacity to compaction and protect primary pores. Early oil charging could lead to temporary cessation of diagenesis and thus inhibit the cementation. When organic acids entered reservoir formations, considerable amounts of secondary pores were formed, leading to the local improvement of petrophysical properties. When predicting good quality belt in exploration of deep basin, it is recommended that the superimposing effects of the multiple factors(overpressure, early oil charging, compositional and textural maturity, diagenesis) be taken into consideration. 展开更多
关键词 Bohai Bay BASIN Raoyang SAG rifted BASIN Shahejie Formation DIAGENESIS high porosity zone DISSOLUTION
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