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Effect of blood transfusion therapy on oxygen saturation in brain and intestinal tissues of children with premature anaemia
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作者 Xin-Mei Lin Chuan-Yan Chen Ping Huang 《海南医科大学学报(英文版)》 2019年第2期74-77,共4页
Objective: To study the effect of blood transfusion therapy on oxygen saturation in brain and intestinal tissues of children with premature anaemia. Methods: Ninety-five children with premature anaemia in our hospital... Objective: To study the effect of blood transfusion therapy on oxygen saturation in brain and intestinal tissues of children with premature anaemia. Methods: Ninety-five children with premature anaemia in our hospital from August 2016 to July 2018 were selected and divided into three groups according to the different degrees of anemia, namely, mild group (n=30), moderate group (n=30) and severe group (n=35), meanwhile, another 35 premature without anemia were set as control group. Then the basal vital signs, levels of hemoglobin (Hb) and hematocrit (Hct), as well as the oxygen saturation in brain and intestinal tissue were compared among the four groups. Results: The SBP and DBP between the four groups after treatment had no difference. The HR and RR after treatment in the control group and the mild group were significantly higher than those in the severe group. The RR of the mild group was significantly lower than that of the control group, with statistical difference. The Hb in the control group and the mild group was significantly higher than that in the moderate group and the severe group. The Hb in the moderate group was significantly higher than that in the severe group. Hct in the control group and the mild group was significantly higher than that in the severe group. The Hct in the moderate group had no statistic difference with that of the mild group and severe group. The cerebral oxygen saturation after treatment in the control group and the mild group was significantly higher than that in the severe group, meanwhile the intestinal tissue oxygen saturation after treatment of the control group was significantly higher than that in the severe group. Cerebral oxygen saturation after treatment showed no difference between the severe group and the moderate group, and the intestinal tissue oxygen saturation after treatment either had no difference among the severe group, the moderate group and the mild group. Conclusion: Blood transfusion therapy can significantly improve the oxygen saturation of brain and in 展开更多
关键词 Blood TRANSFUSION THERAPY PREMATURE delivery Anemia Cerebral OXYGEN SATURATION Intestinal tissue OXYGEN SATURATION
Ultra-deep desulfurization by reactive adsorption desulfurization on copper-based catalysts 预览
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作者 Yaqing Liu Hongying Wang +2 位作者 Jinchong Zhao Yunqi Liu Chenguang Liu 《能源化学:英文版》 SCIE EI CAS CSCD 2019年第2期8-16,共9页
In this paper,a novel copper-based catalyst for FCC gasoline improving the ability of removal the sulfur and avoiding the loss of the octane number from olefin saturation by reactive adsorption desulfurization(RADS) w... In this paper,a novel copper-based catalyst for FCC gasoline improving the ability of removal the sulfur and avoiding the loss of the octane number from olefin saturation by reactive adsorption desulfurization(RADS) was investigated.The series of Cu/Zn O-Al2 O3 catalysts were characterized by X-ray powder diffraction(XRD),N2 adsorption analysis and temperature-programmed reduction(TPR) studies,X-ray photoelectron spectroscopy(XPS),scanning electron microscope(SEM) and transmission electron microscopy(TEM).The experiment results showed that the catalysts had an optimum desulfurization ability with copper loading 6 wt%,which the sulfur contents of product decreased less than 10 μg/g and olefin contents decreased from 16.19% to 14.14% for the long period operation.The appropriate Cu loading content could lead to the high active and low apparent activation energy(Ea).Therefore,the Cu-based catalyst may become a novel catalyst for second-generation for reactive adsorption desulfurization,which achieves the high desulfurization active and low olefins saturation to satisfy the upgrading the product. 展开更多
关键词 Cu/ZnO-Al2O3 DESULFURIZATION activity OCTANE number OLEFINS SATURATION Stability
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基于HSV和HE的复制粘贴篡改检测算法 预览
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作者 甘玲 王凯 《重庆邮电大学学报:自然科学版》 CSCD 北大核心 2019年第3期400-406,共7页
针对块匹配检测算法不能准确提取图像面积较小区域、自然相似区域以及平滑区域特征的问题,提出一种基于HSV(hue,saturation,value)颜色空间和直方图均衡化算法的复制粘贴篡改精确检测与定位的方法。将待测图像从RGB(red,green,blue)颜... 针对块匹配检测算法不能准确提取图像面积较小区域、自然相似区域以及平滑区域特征的问题,提出一种基于HSV(hue,saturation,value)颜色空间和直方图均衡化算法的复制粘贴篡改精确检测与定位的方法。将待测图像从RGB(red,green,blue)颜色空间转换到HSV颜色空间,并通过直方图均衡化算法对图像HSV颜色空间的V通道进行特征增强;提取基于圆谐波变换的特征构建特征向量;使用最近邻搜索算法对构建的特征向量进行快速随机搜索得到稠密的偏移场;采用稠密线性拟合的方法滤除错误匹配,并通过形态学操作标识定位出篡改区域。实验结果表明,所提方法能够有效降低面积较小区域、自然相似区域和平滑区域的误检与漏检像素,从而提升检测结果并准确定位出图像的篡改区域。 展开更多
关键词 复制粘贴篡改 特征提取 特征匹配 HSV颜色空间 直方图均衡化
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Smart homing guidance strategy with control saturation against a cooperative target-defender team 预览
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作者 GUO Hang FU Wenxing +2 位作者 FU Bin CHEN Kang YAN Jie 《系统工程与电子技术:英文版》 SCIE EI CSCD 2019年第2期366-383,共18页
A smart homing guidance strategy with control saturation against a target-defender team is derived. It is noteworthy that a cooperative strategy of the target-defender team is applied,which has been proved more challe... A smart homing guidance strategy with control saturation against a target-defender team is derived. It is noteworthy that a cooperative strategy of the target-defender team is applied,which has been proved more challenging for the homing guidance.The defender missile is launched by the target and guided by a cooperative augmented proportional navigation(APN). At the same time, the target performs a one-switch maneuver to cooperate and minimize the defender’s acceleration requirement. The problem is analyzed for arbitrary-order linear dynamics of the agents in the linearized form but validated by the mathematical simulations by using nonlinear kinematics. The perfect information of three agents’ states is assumed. Then, a method to deal with the target-defender team is proposed. It contains a combined performance index penalizing the miss distance relative to the target and energy consumption in the whole duration. Besides, the specific miss distance related to the defender is regarded as an inequality constraint. An analytical solution for the smart guidance strategy against the APN guided defender is derived. Meanwhile, the control saturations are introduced to get more realistic and reasonable insights to this practical target-missile-defender problem. A simple but effective iterative searching technique is proposed to determine the saturation time points. The solution provides an optimal homing strategy to evade the defender with a specific miss distance and intercept the target with the minimum miss distance in the minimum energy manner. Nonlinear two-dimensional simulation results are used to validate the theoretical analysis. By comparison with the optimal differential game guidance(ODGG) and the combined minimum effort guidance(CMEG), the superiority of this smart guidance strategy is concluded. 展开更多
关键词 SMART HOMING guidance control SATURATION targetmissile-defender ITERATIVE SEARCHING technique
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自动重合闸期间电流互感器剩磁抑制研究
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作者 段建东 金转婷 +4 位作者 雷阳 张小庆 张宜阳 李云阁 左宝峰 《中国电机工程学报》 EI CSCD 北大核心 2019年第5期1498-1505,共8页
P级电流互感器广泛用于330kV及以下电力系统,由于其暂态性能差,在铁心中留存大量剩磁。随着电网短路水平增大,电流互感器更易饱和,造成与之相连的继电保护误动。为此,该文提出一种适用于自动重合闸期间的电流互感器剩磁快速抑制方法。... P级电流互感器广泛用于330kV及以下电力系统,由于其暂态性能差,在铁心中留存大量剩磁。随着电网短路水平增大,电流互感器更易饱和,造成与之相连的继电保护误动。为此,该文提出一种适用于自动重合闸期间的电流互感器剩磁快速抑制方法。该方法由连接在电流互感器二次侧的剩磁抑制电路实现,通过控制开关模块输出电压的极性来逐渐减小铁心的磁通。给出剩磁抑制电路中开关模块输出电压反转次数、直流电压值以及限流电阻的选择方法。利用典型电流互感器参数及其在自动重合闸期间的动态模拟实验数据,进行不同剩磁极性、不同短路电流情况下的测试,结果显示所提出的剩磁抑制方法及其抑制电路是可行的、快速的,并且性能优越。 展开更多
关键词 电流互感器 自动重合闸 剩磁 抑制 动态模拟 饱和
土体热传导性能及其热导率模型研究 预览
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作者 张涛 刘松玉 +2 位作者 张楠 段隆臣 蔡国军 《建筑材料学报》 EI CAS CSCD 北大核心 2019年第1期72-80,共9页
为研究不同土体的热传导特性变化规律,利用热探针测试了南京地区典型土体在不同含水量和干密度状态下的热阻系数,分析了含水量、干密度、饱和度以及矿物成分等因素对土体热阻系数的影响,研究了不同状态下土体热导率的预测模型,提出了适... 为研究不同土体的热传导特性变化规律,利用热探针测试了南京地区典型土体在不同含水量和干密度状态下的热阻系数,分析了含水量、干密度、饱和度以及矿物成分等因素对土体热阻系数的影响,研究了不同状态下土体热导率的预测模型,提出了适用于不同地区土体热阻系数估算的修正系数.结果表明:南京地区典型土体的热阻系数随含水量和干密度增加而减小,当含水量超过一定范围后,热阻系数趋于稳定;热阻系数与饱和度之间的关系表现出与其含水量之间相似的变化规律;土颗粒的热传导特性由其矿物成分决定,石英含量对土颗粒热传导特性有着显著影响;提出了可用于非饱和土热导率估算的修正归一化模型,该模型对于粗粒土具有较高的预测精度,细粒土则需考虑区域差别进行修正. 展开更多
关键词 热传导 饱和度 矿物成分 非冻土 归一化模型
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电流互感器饱和检测的混合算法及其工程实现
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作者 郑茂然 张志良 +1 位作者 栾俐 张啸宇 《电气应用》 2019年第6期36-42,共7页
由于铁心的非线性励磁特性,电力系统中配置的铁磁式电流互感器易受外部因素影响发生磁饱和,从而导致一次电流无法正常传变,这既可能引起保护装置对系统运行状态的错误判断,也在一定程度上反映着电流互感器(TA)设备性能的变化。为准确识... 由于铁心的非线性励磁特性,电力系统中配置的铁磁式电流互感器易受外部因素影响发生磁饱和,从而导致一次电流无法正常传变,这既可能引起保护装置对系统运行状态的错误判断,也在一定程度上反映着电流互感器(TA)设备性能的变化。为准确识别TA饱和并深入分析设备发生饱和的规律,对基于TA饱和的谐波与波形特征而提出的一种谐波比和分段积分法相结合的TA饱和检测混合算法进行了深入的探讨。并针对混合算法在实际工程应用中面临的多种技术问题,结合现场的大量录波数据,对混合算法进行改进以完善其工程实用性。算例分析表明,改进后的混合算法既能有效识别TA饱和,又利于利用录波数据快速准确收集TA饱和信息,为评价TA性能及分析饱和发生规律创造了条件。 展开更多
关键词 电流互感器 饱和 故障录波 谐波比 分段积分法
裂隙充填型天然气水合物储层的各向异性饱和度新估算及其裂隙定量评价
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作者 钱进 王秀娟 +2 位作者 董冬冬 SAINKalachand 叶月明 《地球物理学进展》 CSCD 北大核心 2019年第1期354-364,共11页
天然气水合物有时会以结核状、层状、脉状或块状等裂隙形态发育在深水盆地的细粒泥质沉积物中,该类型天然气水合物被称为裂隙充填型.与孔隙充填型不同,裂隙充填型天然气水合物储层由于裂隙的出现,在测井速度、电阻率和地震数据上会呈现... 天然气水合物有时会以结核状、层状、脉状或块状等裂隙形态发育在深水盆地的细粒泥质沉积物中,该类型天然气水合物被称为裂隙充填型.与孔隙充填型不同,裂隙充填型天然气水合物储层由于裂隙的出现,在测井速度、电阻率和地震数据上会呈现明显的各向异性特征.本文利用细层层状介质模型和有效介质理论(EMT)新估算出印度克里希纳—戈达瓦里(K-G)盆地NGHP-01-10A和10D孔裂隙充填型水合物储层的各向异性饱和度,纵波(Vp)和垂直极化横波(Vsv)测井速度估算的平均饱和约为20%,明显优于水平极化横波(Vsh)估算结果,且与压力取心估算结果更为一致.倾角随深度变化曲线和不同角度估算的水合物饱和度结果都表明10A孔浅部以高倾角裂隙为主,深部出现低倾角裂隙;10D孔以垂直裂隙为主,这说明两口相距10 m的孔中裂隙在空间上延伸长度较小;而10B-08Y岩心的X射线成像定量评价结果显示水平裂隙倾角位于0°~21°,高倾角裂隙倾角位于68°~89°,裂隙尺度为厘米级,最大高度、宽度和纵横比分别为27.66 cm、6.71 cm和170.此外,水合物饱和度估算的影响因素分析表明,地层岩性和方程计算参数对饱和度估算的准确与否至关重要,与简化三相方程相比,有效介质理论计算参数的物理意义明确,参数选择简易,因此计算也更为准确与便捷. 展开更多
关键词 裂隙充填型天然气水合物 有效介质理论 裂隙定量评价 各向异性 饱和度
岩电实验和数值模拟相结合精确评价致密气储层饱和度 预览
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作者 张宏悦 韩艺 《当代化工》 CAS 2019年第4期795-798,803共5页
致密储层由于岩性?孔隙类型与孔隙结构复杂多样及非均质性强等特征,使得驱替法岩石电性实验达不到理想的驱替效果,难以得到中低含水饱和度实验数据,导致饱和度测井评价遇到很大困难,测井符合率低?选择以有效介质和逾渗理论为基础的网络... 致密储层由于岩性?孔隙类型与孔隙结构复杂多样及非均质性强等特征,使得驱替法岩石电性实验达不到理想的驱替效果,难以得到中低含水饱和度实验数据,导致饱和度测井评价遇到很大困难,测井符合率低?选择以有效介质和逾渗理论为基础的网络模型,对致密岩样进行数值模拟以求得含水饱和度全程段的电阻率指数变化趋势,既利用了岩电实验真实饱和度范围的测量参数,又弥补物理实验驱替不完全的缺陷;发现了所研究样品的电阻率指数与含水饱和度呈现出指数关系,而不是乘幂关系,由此建立了新的饱和度评价模型,在鄂尔多斯盆地某区块山西组致密气储层得到更为精确的饱和度。 展开更多
关键词 致密气 饱和度 数值模拟 鄂尔多斯盆地
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Effect of retained austenite and nonmetallic inclusions on the thermal/electrical properties and resistance spot welding nuggets of Si-containing TRIP steels 预览
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作者 V.H.Vargas I.Mejía +1 位作者 V.H.Baltazar-Hernández C.Maldonado 《矿物冶金与材料学报:英文版》 SCIE EI CAS CSCD 2019年第1期52-63,共12页
Five advanced high-strength transformation-induced plasticity(TRIP)steels with different chemical compositions were studied to correlate the retained austenite and nonmetallic inclusion content with their physical pro... Five advanced high-strength transformation-induced plasticity(TRIP)steels with different chemical compositions were studied to correlate the retained austenite and nonmetallic inclusion content with their physical properties and the characteristics of the resistance spot welding nuggets.Electrical and thermal properties and equilibrium phases of TRIP steels were predicted using the JMatPro software.Retained austenite and nonmetallic inclusions were quantified by X-ray diffraction and saturation magnetization techniques.The nonmetallic inclusions were characterized by scanning electron microscopy.The results show that the contents of Si,C,Al,and Mn in TRIP steels increase both the retained austenite and the nonmetallic inclusion contents.We found that nonmetallic inclusions affect the thermal and electrical properties of the TRIP steels and that the differences between these properties tend to result in different cooling rates during the welding process.The results are discussed in terms of the electrical and thermal properties determined from the chemical composition and their impact on the resistance spot welding nuggets. 展开更多
关键词 transformation-induced plasticity steel retained austenite non-metallic inclusions magnetic saturation electrical PROPERTIES THERMAL PROPERTIES resistance spot welding NUGGET
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光纤纵联保护装置在企业配网线路的应用分析 预览
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作者 刘艳芬 《包钢科技》 2019年第1期87-90,共4页
文章介绍了三种近年来在企业中压配电系统中应用的微机型线路光纤纵联保护装置,针对企业中压配电系统的特点,分别阐述了电流互感器饱和对保护装置启动值的影响以及保护对通讯的要求,最后对企业中压配电系统设备选择以及光纤纵联保护装... 文章介绍了三种近年来在企业中压配电系统中应用的微机型线路光纤纵联保护装置,针对企业中压配电系统的特点,分别阐述了电流互感器饱和对保护装置启动值的影响以及保护对通讯的要求,最后对企业中压配电系统设备选择以及光纤纵联保护装置的通道维护给出了建议,对实际工作具有一定的指导意义。 展开更多
关键词 光纤纵联保护 启动值 电流互感器 饱和 通讯
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湖泊岸边红壤土渗流对杆塔接地电阻的影响
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作者 李洪涛 李恒真 陈斯翔 《水电能源科学》 北大核心 2019年第6期169-172,177共5页
为研究湖泊水分渗透对红壤土区的杆塔接地装置电阻的影响,采用有限元法结合试验研究了红壤土电阻率与饱和度的关系及水分渗透过程,在CDEGS中构建接地装置模型,提出水分影响系数的概念,计算渗透存在对湖泊周边杆塔接地装置接地电阻的影... 为研究湖泊水分渗透对红壤土区的杆塔接地装置电阻的影响,采用有限元法结合试验研究了红壤土电阻率与饱和度的关系及水分渗透过程,在CDEGS中构建接地装置模型,提出水分影响系数的概念,计算渗透存在对湖泊周边杆塔接地装置接地电阻的影响。结果表明,红壤土电阻率对水分十分敏感,渗透会改变土壤饱和度的分布,引起土壤电阻率降低,使接地电阻下降;离湖泊越远,杆塔接地电阻越大,水分影响系数越大,水分影响系数呈缓慢-迅速-缓慢的上升趋势。 展开更多
关键词 红壤土 电阻率 杆塔 接地电阻 饱和度 水分影响系数
Controlling nested wrinkle morphology through the boundary effect on narrow-band thin films
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作者 Hanyang XU Tielin SHI +1 位作者 Guanglan LIAO Qi XIA 《机械工程前沿:英文版》 CSCD 2019年第2期235-240,共6页
We describe the formation of nested wrinkles created by the thermal mismatch between a narrow-band thin film and a compliant substrate.When a film is described as"narrow-band",it literally means that the fil... We describe the formation of nested wrinkles created by the thermal mismatch between a narrow-band thin film and a compliant substrate.When a film is described as"narrow-band",it literally means that the film band width is much shorter than its length;more precisely,it means that the width is comparable with the wavelength of the wrinkles.A silicon mask was used during film sputtering to create narrow-band films on poly(dimethylsiloxane)substrate,thus creating regular boundaries to steer local stresses and control wrinkle morphology.Disordered nano-scale wrinkles were found nested within highly ordered micro-scale sinusoidal wrinkles.The formation of nested wrinkles was explained through the amplitude and wavelength saturation of nano-scale wrinkles.The disordered morphology of nano-scale wrinkles and the highly ordered morphology of microscale wrinkles were explained by using the boundary effect. 展开更多
关键词 nested and hierarchical WRINKLES MORPHOLOGY AMPLITUDE SATURATION boundary effect
风电次同步谐振对主变偏磁的影响机理
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作者 曹建春 项祖涛 +3 位作者 武丹 燕翚 王宇红 曲国权 《电网技术》 EI CSCD 北大核心 2019年第6期2080-2086,共7页
风电经串补送出系统发生次同步谐振(subsynchronousresonance, SSR)现象时,风电场和相关汇集站的主变会出现异响和振动加剧现象,给电力系统安全稳定运行带来隐患。通过分析工程现场SSR故障录波和系统的等效电路,提出超过一定量的次同步... 风电经串补送出系统发生次同步谐振(subsynchronousresonance, SSR)现象时,风电场和相关汇集站的主变会出现异响和振动加剧现象,给电力系统安全稳定运行带来隐患。通过分析工程现场SSR故障录波和系统的等效电路,提出超过一定量的次同步电流注入含串补的系统后,造成主变铁芯周期性正负交替偏磁饱和,从而导致主变励磁电流增大、异响和振动加剧。通过 RTDS(real time digital simulator)仿真和物理变压器低压模型实验,对上述机理和现象进行了验证。适当降低系统工频电压运行水平,可以一定程度减小谐振时主变偏磁饱和的程度和危害;而采取适当措施抑制SSR,是解决上述问题的根本方法。 展开更多
关键词 风电场 次同步谐振 主变振动 偏磁 饱和
二氧化碳驱动用储层微观界限研究 预览
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作者 邓瑞健 田巍 +2 位作者 李中超 赵良金 戴厚柱 《特种油气藏》 CAS CSCD 北大核心 2019年第3期133-137,共5页
为深入研究CO2驱动用储层的微观界限,采用微观可视化模型与岩心实验相结合的方法,分别研究了CO2驱的微观驱替特征和微观作用孔喉范围,进一步验证了CO2驱是老油田效益开发可行的技术手段。研究表明:CO2具有较高的洗油效率,并具有扩大波... 为深入研究CO2驱动用储层的微观界限,采用微观可视化模型与岩心实验相结合的方法,分别研究了CO2驱的微观驱替特征和微观作用孔喉范围,进一步验证了CO2驱是老油田效益开发可行的技术手段。研究表明:CO2具有较高的洗油效率,并具有扩大波及体积的作用,CO2可将孔道中的原油驱替采出,能将孔道中的剩余油抽提采出;在水驱的基础上CO2将动用储量微观空间降低一个数量级,使孔喉半径大于10-2μm以上的原油储集空间都成为CO2驱可动用空间,增加了可动用储量范围。采用CO2驱新增可动用储量达20. 00个百分点以上,渗透率越低,水驱后采用CO2驱新增可动用储量越多。研究成果为CO2驱的实施提供了理论基础,同时也为老油田效益开发提供重要参考。 展开更多
关键词 动用储量 剩余油 孔喉空间 饱和度 微观界限
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基于核磁共振实验的低渗透砂岩岩电参数分类及应用——以东营凹陷南坡沙四段为例 预览
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作者 闫建平 张帆 +3 位作者 王敏 唐洪明 胡钦红 张欣吉 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2019年第7期2748-2758,共11页
低渗透砂岩储层孔隙结构复杂,储层有效性识别及饱和度准确计算难度较大.笔者以东营凹陷南坡沙四段(Es4)低渗透砂岩为研究对象,根据压汞、物性、薄片及核磁等资料,将研究区孔隙结构分为三大类、五小类.在岩样孔隙结构分类基础上,明确了... 低渗透砂岩储层孔隙结构复杂,储层有效性识别及饱和度准确计算难度较大.笔者以东营凹陷南坡沙四段(Es4)低渗透砂岩为研究对象,根据压汞、物性、薄片及核磁等资料,将研究区孔隙结构分为三大类、五小类.在岩样孔隙结构分类基础上,明确了孔隙结构类型与岩电参数之间存在确定的关系,而核磁共振T2谱定量特征参数在一定程度上能够表征孔隙结构类型及其细节信息,通过提取T2谱中T2几何平均值(T2g)、T2均值(2)、峰度(KG)、可动流体分量(Smf)及区间孔隙分量等孔隙结构参数,建立了基于核磁T2谱特征参数的孔隙结构识别图版,显示核磁T2谱孔隙结构参数对不同类型的储层有较好的识别效果,进而探讨核磁孔隙结构参数和岩电参数之间的关系,结果表明,T2谱峰度值与孔隙胶结指数(m)值相关性较高,进一步确定了岩电参数m的核磁计算公式.最终,将该套方法应用于研究区井筒剖面中,有效地提高了饱和度计算精度,也为东营凹陷南坡低渗透砂岩油藏储量估算与高效开发提供了依据. 展开更多
关键词 低渗透砂岩 孔隙结构 核磁共振T2谱 岩电参数 饱和度
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基于阻抗特征煤体中瓦斯因素对水合动力学的影响
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作者 张强 吴强 +2 位作者 张辉 张保勇 刘传海 《工程热物理学报》 EI CAS CSCD 北大核心 2019年第2期414-422,共9页
为研究不同瓦斯赋存条件下水合机理防治煤与瓦斯突出的基础规律,利用阻抗特性监测与高压瓦斯水合实验一体化装置,针对4种瓦斯气体分别在4种赋存压力(4 MPa,5 MPa,6 MPa,7 MPa)条件下开展煤体中瓦斯水合实验,根据阻抗特征获取了瓦斯水合... 为研究不同瓦斯赋存条件下水合机理防治煤与瓦斯突出的基础规律,利用阻抗特性监测与高压瓦斯水合实验一体化装置,针对4种瓦斯气体分别在4种赋存压力(4 MPa,5 MPa,6 MPa,7 MPa)条件下开展煤体中瓦斯水合实验,根据阻抗特征获取了瓦斯水合物形成诱导时间,计算了煤体中瓦斯水合物生长速率与饱和度。结果表明:煤体中瓦斯水合过程中上层位与中层位阻抗逐渐增大,下层位阻抗逐渐减小,瓦斯水合物主要分布于上层位与中层位煤体中;随初始压力变化瓦斯水合物形成诱导时间未呈现规律性变化,随着混合气中CH4浓度的下降,诱导时间先减小后增大,实验范围内平均诱导时间为41 min,分布范围为18~74 min;随初始压力与瓦斯气体组分浓度的变化煤体中瓦斯水合物平均生长速率呈振荡变化趋势,平均生长速率均值为0.58 cm3·min-1,最快为0.84 cm3·min-1;煤体中瓦斯水合物的饱和度随初始压力与瓦斯中CH4浓度的增大呈逐渐升高的变化趋势,水合物饱和度范围为17.03%~57.03%。 展开更多
关键词 瓦斯 水合物 阻抗 动力学参数 饱和度
Shear strength of extremely altered serpentinites based on degree of saturation(Ankara, Turkey)
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作者 Koray ULAMIs 《山地科学学报:英文版》 SCIE CSCD 2019年第4期944-954,共11页
The term 'mélange' has several definitions due to the origin, tectonic and petrographical features. The geotechnical engineering behaviors of mélanges are either dominated by different kinds of intac... The term 'mélange' has several definitions due to the origin, tectonic and petrographical features. The geotechnical engineering behaviors of mélanges are either dominated by different kinds of intact rock blocks or matrix material. Landslides were encountered within the serpentinite matrix of Ankara Mélange, which is a typical bimrock mass. The residual sections of the extremely altered serpentinites are sandy soils. Such soils undergo rapid change of saturation, leading to shear strength reduction. Undisturbed and disturbed samples were obtained from the outcrops for shear box tests. Geochemical and petrographical composition of the serpentinites were determined by XRF(X Ray Fluorescence), XRD(X-ray diffraction) and thin section inspections, in order to outline the alteration process. Based on field observations, physically decomposed core stones exist beneath 40-120 cm thick residual green and grey-dark grey residual sandy soil. Physical and mechanical properties of the soils were tested with particular emphasis on residual shear strength parameters. Disturbed samples were remolded by standard compaction. The field work was completed during both rainy and summer seasons. Disturbed samples were prepared using phase diagrams in order to attain varying saturation degree. Two distinct sandy soil groups were determined through classification tests. The volumetric compression and/or expansion of the loose and dense samples were also considered based on the angle of dilatancy. A series of consolidated and drained shear box tests were conducted with ascending degree of saturation. The reduction of effective apparent cohesion, internal friction angle and dilatancy angle were determined to obtain a threshold of the degree of saturation. All the sand samples had zero residual internal friction angle and/or apparent cohesion after reaching 70% degree of saturation. 展开更多
关键词 MÉLANGE SERPENTINITE Shear strength Saturation DILATANCY ANKARA
基于浮动门槛值的改进电流互感器饱和识别方法研究 预览
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作者 张凌浩 刘建坤 卜京 《电力工程技术》 2019年第3期115-120,共6页
线路纵联通道中传统电流互感器(CT)与电子式电流互感器(ECT)混用时,CT饱和可能导致线路差动保护不正确动作。目前虚拟制动电流法是解决这一问题的常用方法,但虚拟制动电流法开放差动保护门槛值固定,并未考虑线路参数变化对其的影响,使... 线路纵联通道中传统电流互感器(CT)与电子式电流互感器(ECT)混用时,CT饱和可能导致线路差动保护不正确动作。目前虚拟制动电流法是解决这一问题的常用方法,但虚拟制动电流法开放差动保护门槛值固定,并未考虑线路参数变化对其的影响,使得开放差动保护时间较长。针对这一问题,文中在虚拟制动电流法基础上,提出了一种基于浮动门槛值的改进方法。通过对CT进行建模,获取线路参数与饱和程度关系,计算出浮动门槛值参考曲线,并根据具体线路参数自适应选取门槛值,以确保差动保护不误动,同时缩短差动保护闭锁时间。仿真表明,该方法能够有效提高灵敏性,减小差动闭锁时间,并具有较大的适用范围。 展开更多
关键词 电流互感器 饱和 浮动门槛值 线路参数 差动保护
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秭归地区陆源碎屑岩导热系数试验研究
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作者 乔宇 骆进 +3 位作者 项伟 黄维 郭清海 张琦 《地质科技情报》 CAS CSCD 北大核心 2019年第1期82-89,共8页
岩土体的导热系数是重要的物理参数,在岩土工程中有着广泛应用。秭归地区的黄陵背斜西翼是我国南方著名的标准地层剖面,以秭归地区黄陵背斜西翼岩层陆源碎屑岩为研究对象开展导热系数试验研究,可为我国南方地区开展地热能开发、隧道工... 岩土体的导热系数是重要的物理参数,在岩土工程中有着广泛应用。秭归地区的黄陵背斜西翼是我国南方著名的标准地层剖面,以秭归地区黄陵背斜西翼岩层陆源碎屑岩为研究对象开展导热系数试验研究,可为我国南方地区开展地热能开发、隧道工程及矿产开采等科研工作提供重要的参考依据。探究了各岩层岩石导热系数与岩石颗粒组分、胶结物之间的变化规律及差异性。试验结果表明,黄陵背斜西翼陆源碎屑岩导热系数差异较大,在0.72~4.47 W/(m·K)之间,且导热系数大小为石英砂岩>粉砂岩>泥岩。陆源碎屑岩导热系数受岩石岩性、颗粒组分、粒径、胶结类型及含水状态的影响较大。 展开更多
关键词 黄陵背斜西翼 陆源碎屑岩 导热系数 饱和度
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