期刊文献+
共找到163篇文章
< 1 2 9 >
每页显示 20 50 100
Phanerozoic Quartz Arenite Formation and Sequence-Analytical Patterns: Indirectly Relating to Major Impacting and Super Plume Volcanism, Jordan, Arabian Plate 被引量:2
1
作者 Werner Schneider Elias Salameh 《Open Journal of Geology》 2020年第1期13-52,共40页
This paper deals with indirect effects of major impacting throughout the Early Paleozoic resp. with those of super plume activity during the Early Cretaceous, both applied to the siliciclastic series of Jordan deposit... This paper deals with indirect effects of major impacting throughout the Early Paleozoic resp. with those of super plume activity during the Early Cretaceous, both applied to the siliciclastic series of Jordan deposited on the Arabian Platform, Arabian Plate. Its focus is mainly directed on gases released by both processes (CO2, SO2, NOx, HCl, HF) and the relating acids, challenged by experiments and microscopic analysis of grain mounts and thin sections that reveal chemical instability of quartz and ultrastable heavy minerals (i.e. tourmaline) under high acidity (pH °C - 90°C). According to Lopatin’s Time/Temperatur-Index the Lower Cambrian reached the onset of hydrocarbon generation (liquid window) during the Lower Early Cretaceous. Unstable heavy minerals (apatite, garnet, hornblende, epidote, zoisite/clinozoisite) are generally absent in quartz arenites while in arkosic sandstones of marine environment carbonate cement and primary clay minerals (illite) provide conservation. As known since the eighties, the K/T-event’s indirect effects had global influence on Earth’s surface sediments and atmospheric chemistry by wildfires, hot whirl storms, acidic “sturz rain”, dust, soot, darkness, loss of photosynthesis, toxic metals, gases and relating acids. All of them are here concerned and applied to major impacting throughout the Early Paleozoic using the impact data of Price (2001);while superplume volcanism during Cretaceous led to the opening of the South Atlantic accompanied by the cyclic outflow of the Para?a/Etendeka Flood Basalts and relating gases in a gigantic scale (137 - 127 Ma). Assuming that the gases cause similar global effects on Earth’s surface sediments, an according result may be expected in form of quartz arenites and their sequence-analytical patterns (cyclic SBs, MFSs).* 展开更多
关键词 Interrelationship Chronostratigraphic and Lithostratigraphic b. Sequence-Analysis (SB MFS) MAJOR Impacting and Super PLUME VOLCANISM (Gases!) Mass Extinction plate Tectonics Diagenesis QUARTZ Arenite EARLY Paleozoic and EARLY Cretaceous Jordanian Platform arabian plate (correlations)
下载PDF
Geochemistry and Petrogenesis of Intracontinental Basaltic Volcanism on the Northwest Arabian Plate,Gaziantep Basin,Southeast Anatolia,Turkey
2
作者 Sevcan KURUM Abdurrahman BOLUCU Melek URAL 《Acta Geologica Sinica(English Edition)》 CAS CSCD 2018年第2期519-535,共17页
Volcanism along the northwest boundary of the Arabian Plate found in the Gaziantep Basin, southeast Turkey, is of Miocene age and is of alkaline and calc-alkaline basic composition. The rare earth element data for bot... Volcanism along the northwest boundary of the Arabian Plate found in the Gaziantep Basin, southeast Turkey, is of Miocene age and is of alkaline and calc-alkaline basic composition. The rare earth element data for both compositional series indicates spinel-peridotite source areas. The rare earth and trace elements of the alkaline lavas originate from a highly primitive and slightiy contaminated asthenospheric mantle; those of the calc-alkaline lavas originate from a highly heterogeneous, asthenospheric, and lithospheric mantle source. Partial melting and magmatic differentiation processes played a role in the formation of the petrological features of these volcanics. These rocks form two groups on the basis of their 87Sr[S6Sr and 143Nd/lI4Nd isotopic compositions in addition to their classifications based on their chemical compositions (alkaline and calc-alkaline). These isotopic differences indicate a dissimilar parental magma. Therefore, high Nd isotope samples imply a previously formed and highly primitive mantle whereas low Nd isotope samples may indicate comparable partial melting of an enriched heterogeneous shallow mantle. Other isotopic changes that do not conform to the chemical features of these lavas are partly related to the various tectonic events of the region, such as the Dead Sea Fault System and the Bitlis Suture Zone. 展开更多
关键词 PETROGRAPHY GEOCHEMISTRY isotopes basaltic volcanism arabian plate TURKEY
下载PDF
The Permian-Triassic Transitional Zone: Jordan, Arabian Plate;Linked to Siberian Large Igneous Province and Neo-Tethys Breakup Degassing via Climate Forcing, Atmospheric Hazard and Metal Toxicity
3
作者 Werner Schneider Elias Salameh 《Open Journal of Geology》 2022年第6期472-503,共32页
End-Permian Gondwana siliciclastics (50 - 70 m) of the Um Irna F exposed along the NE Dead Sea, exhibit carbonate-free fining upward cycles (FUC) deposited during acid flash flood events under tropical climate. Severa... End-Permian Gondwana siliciclastics (50 - 70 m) of the Um Irna F exposed along the NE Dead Sea, exhibit carbonate-free fining upward cycles (FUC) deposited during acid flash flood events under tropical climate. Several ferruginous paleosol intercalations cover periods of drying upward formation (DUP) under semiarid/arid climates. Thin grey pelite beds interbedded between paleosol and overlying FUC, are interpreted as tephra deposits sourced in Siberian LIP- and Neo-Tethys (NT)-Degassing. The Wadi Bassat en Nimra-section exhibits the P-T transitional zone where flash flood deposits meet supra-/intertidal sediments of the southward-directed transgressive NT. Decreasing flash-flooding continued through the Lower Scythian (Ma’in F.) during transgression, reworking, and resedimentation. Two euryhaline foraminifera-bearing limestone beds are discussed as indicators for the end of mass extinction (recovery phase: ca. 250.8 - 250.4 Ma) possibly correlating with the Maximum Flooding Surface MFS Tr 10 (ca. 250.5 Ma) on the Arabian Shelf (Khuff cycles B;A). Comparable data from the Germanic Basin as FUC/DUP-cycles, tephrasuspicious “Grey Beds” with high concentrations of As, Co, Pb, Zn, and Cu as well as the U-Pb Age data of the Siberian LIP meet the PTB-Zone between the MFSs Intervals P 40 (ca. 254 Ma)/Tr 10 (ca 250.5 Ma) on the Arabian Shelf. MFS (Tr 10, 20, 30) and SBs resp. on the Arabian Plate, as well as Scythian Substage boundaries correlate with &#8706<sup>13</sup> C-excursions recorded at Musandam, UAE. Thereby, the ratio of greenhouse gases (+climate forcing)/aerosols und tephra (-climate forcing) takes a significant influence on the &#8706<sup>13</sup>C-Variation. 展开更多
关键词 P-T Transition Zone JORDAN arabian plate SILICICLASTICS Flash Flood Deposits Neo-Tethys Transgression Siberian LIP Degassing: Acid Rain Tuffs Metal Toxcicity Climate Forcing Milankovitch Croll Cycles Germanic Basin (Correlation) Earth/Moon Interplay Self-Regulation (Autopoiesis)
下载PDF
A Discussion on Correlations of Plate Motion with Seismic Anisotropy and Stress Field in Plate Boundary Zones
4
作者 Han Peng Liu Qianqian +1 位作者 Sun Zhentian Wei Dongping 《Earthquake Research in China》 CSCD 2015年第3期319-330,共12页
In many parts of the global plates,including subduction zones,mid-ocean ridges and even the interior of the continental plates,seismic anisotropy has a certain correlation with image of absolute plate motion( APM),or ... In many parts of the global plates,including subduction zones,mid-ocean ridges and even the interior of the continental plates,seismic anisotropy has a certain correlation with image of absolute plate motion( APM),or is in accord with the predominant direction of the intraplate stress field. In our study,a statistical analysis is done on the correlations of plate motion with seismic anisotropy as well as a stress field within nine plate boundaries which contain major subduction zones in the globe. Results indicate that absolute or relative plate motion( RPM) controls the seismic anisotropy and stress field of the plate boundary,which is especially obvious for the RPM. It can also be inferred that the correlation of RPM is better than that of APM. Because of the complexity of subduction mechanism and diversity of controlling factors at plate boundaries containing subduction zones,the correlation becomes much complex. Sources of anisotropy at various depths show different characteristics,and stress state is controlled by many factors,thus further discussions on the correlations are required. 展开更多
关键词 Seismic anisotropy plate motion Stress field Correlation
下载PDF
Correlation between plate age and layer separation of double seismic zones 被引量:1
5
作者 Keliang Zhang and Dongping Wei 《Earthquake Science》 CSCD 2012年第1期95-101,共7页
Global seismicity catalogs are sufficient for characterizing double seismic zones (DSZs) in subducting slab and facilitate to estimate layer separation without inconsistent uncertainties as local catalogs. Previous ... Global seismicity catalogs are sufficient for characterizing double seismic zones (DSZs) in subducting slab and facilitate to estimate layer separation without inconsistent uncertainties as local catalogs. Previous studies have shown the correlation between DSZs layer separation and plate age while correlation for those younger than -60 Ma is suspicious. The lacking of DSZs with layer separation less than 10 km further makes it difficult to precisely estimate such correlation. Thus, we incorporate eight DSZs data determined through local seismicity into globally-determined dataset and reexamine such correlation. The best fitting results show that both a linear model and a square root of plate age can mathematically fit the layer separation well. However, it is difficult to distinguish these two models when plate age is greater than -20 Ma since their difference is less than 2 km. However, if extrapolation is possible, both models should provide physical information that DSZs will not form if there is no subducting lithosphere. As a result, the DSZs cannot be produced until the oceanic lithospheric age becomes greater than 0.9 Ma in the square root model while the linear model gives a misleading result. As such the square root model demonstrates the relationship physically better than the linear one, it still needs further test in the future with more available data, nevertheless, our study might also provide evidence for the suggestion that the plate age is a primary control factor of the DSZs geometry as well as the subducting process which disregards any local tectonic stresses. 展开更多
关键词 double seismic zone layer separation plate age CORRELATION best fitting
下载PDF
Experimental and Numerical Investigations on Plate-Type Heat Exchanger Performance 被引量:1
6
作者 Yasuyuki Ikegami Sami Mutair Yusuke Kawabata 《Open Journal of Fluid Dynamics》 2015年第1期92-98,共7页
Low-grade Thermal Energy Conversion (LTEC) is a potential source of renewable energy. One of its forms is the Ocean Thermal Energy Conversion (OTEC) in which the temperature difference between the warm surface water a... Low-grade Thermal Energy Conversion (LTEC) is a potential source of renewable energy. One of its forms is the Ocean Thermal Energy Conversion (OTEC) in which the temperature difference between the warm surface water and the cold deep water of the ocean is utilized in driving a heat engine cycle. Unlike the conventional thermal power generation systems, the temperature difference between the heat source and heat sink in OTEC system is relatively small. Therefore, efficient heat exchangers should be used since heat exchangers play a major role in the overall system performance and economics. Due to their efficiency even in operating at small temperature difference, plate heat exchangers are strong candidates in OTEC systems. In this study, performance of a herringbone plate-type heat exchanger is experimentally investigated. Moreover, numerical simulation results obtained by using Fluent CFD software are compared with the experimental results and found in good agreement. 展开更多
关键词 CFD Simulation Nusselt CORRELATION plate HEAT EXCHANGER
下载PDF
90% <i>SNR</i>Improvement with Multi-Port Hall Plates
7
作者 Udo Ausserlechner 《Journal of Applied Mathematics and Physics》 2020年第8期1568-1605,共38页
For Hall plates, the ratio of signal over thermal noise is determined by material properties, thickness, layout geometry, magnetic field, and the electric power at which the plate is operated. For traditional Hall pla... For Hall plates, the ratio of signal over thermal noise is determined by material properties, thickness, layout geometry, magnetic field, and the electric power at which the plate is operated. For traditional Hall plates with four contacts, the optimum choice is a symmetrical device with medium-sized contacts. This paper shows that the signal-to-noise-ratio (<em>SNR</em>) can be further increased by up to 90% for Hall plates with more than four contacts. Supply currents flow through several pairs of contacts, while a signal conditioning circuit taps output voltages at all pairs of contacts and sums them up. We compute the total thermal noise of the sum of correlated noise voltages and relate it to the total magnetic sensitivity. We also prove that for electrically linear devices a spinning current scheme cancels out zero point errors (offset errors) in a strict sense. All our investigations use the definite resistance matrix of multi-port Hall plates. We develop an analytical theory based on recent advances in the theory of Hall plates, and then we compute the integrals and matrices numerically for symmetrical Hall plates with six to 40 contacts. We also present measurements in accordance with our theory. 展开更多
关键词 Multi-Port Hall plates Noise Correlation Noise Efficiency Signal to Noise Ratio Spinning Scheme Thermal Noise Toeplitz Matrix
下载PDF
The Ultimate Noise Limit for Hall Plates in Voltage, Current, and Hybrid Operating Modes
8
作者 Udo Ausserlechner 《Journal of Applied Mathematics and Physics》 2020年第12期3019-3059,共41页
If Hall plates are used as magnetic field sensors they are usually powered up by a current source connected to a pair of non-neighboring contacts. The output voltage is tapped at another pair of non-neighboring contac... If Hall plates are used as magnetic field sensors they are usually powered up by a current source connected to a pair of non-neighboring contacts. The output voltage is tapped at another pair of non-neighboring contacts. In this paper we study more general operating conditions of Hall plates with an arbitrary number of contacts. In such hybrid operating modes current sources are connected to a first set of contacts and voltage sources to a second set of contacts. Output voltages are tapped at the first set of contacts and output currents are measured at the second set of contacts. All these output signals are multiplied by coefficients and added up. The purpose of this work is to figure out which operating mode and which Hall plate achieve maximum signal at minimum thermal noise and power dissipation. To this end we develop a theory, which gives the ratio of signal over noise and power as a function of the resistance matrix of Hall plates, of the supply voltages and currents, and of the coefficients. Optimization is done analytically in closed form and numerically for specific examples. The results are: 1) all operating modes have identical noise performance if their parameters are optimized;2) for any Hall plate one can measure its resistance matrix and insert its values into our formulae to obtain the optimum supply currents and coefficients for optimum noise performance. 展开更多
关键词 Canonical-Correlation Analysis Fractional Programming Hybrid N-Pole Matrix Multi-Port Hall plates Noise Efficiency Rayleigh Quotient Signal to Noise Ratio
下载PDF
沥青路面实测面层层底横向水平应变响应分析
9
作者 潘勤学 胡嘉 +2 位作者 张建 孙杰 谌旎偲 《公路交通科技》 CAS CSCD 北大核心 2024年第10期82-89,共8页
为了揭示沥青路面应变响应的变化规律,通过现场埋设光纤光栅应变及温度传感器,对半刚性基层沥青路面结构开展了不同温度下承载板竖向变形及沥青面层横向应变的同步测试研究,构建了承载板各级荷载下的路表竖向变形与中面层层底横向应变... 为了揭示沥青路面应变响应的变化规律,通过现场埋设光纤光栅应变及温度传感器,对半刚性基层沥青路面结构开展了不同温度下承载板竖向变形及沥青面层横向应变的同步测试研究,构建了承载板各级荷载下的路表竖向变形与中面层层底横向应变的量化关系模型;进而建立了横向应变随温度和行车速度变化的量化关系模型。结果表明:动、静载作用下沥青中面层横向水平应变均有明显的黏弹塑特性,横向静应变历时曲线特征与Burgers模型吻合,横向动应变历时曲线呈现压拉波形,横向动、静应变值均随路表温度的增加而非线性增加,且应变增加幅度随温度的升高而逐渐减小,二者与温度均呈良好的单对数相关关系,据此得到了实测应变的温度修正系数计算公式;沥青中面层层底的横向应变随行车速度的增加而减小,且减小幅度在低车速(≤5 km/h)时较大,高车速(>5 km/h)时较小,二者呈良好的幂函数相关关系;承载板各级荷载下的路表竖向变形及中面层层底横向应变的实测结果与有限元数值计算结果的变化规律一致,这表明沥青路面结构的测试结果能有效表征路面结构的真实应变行为。研究结果为承载板试验预估横向应变提供了依据,可供沥青路面检测与养护决策参考。 展开更多
关键词 道路工程 横向应变 承载板试验 沥青面层 温度修正 相关性
下载PDF
拉伸载荷下含缺陷管道宽板力学响应与断裂失效试验
10
作者 钟光兰 张丹 +1 位作者 闫生栋 郭海林 《福州大学学报(自然科学版)》 CAS 北大核心 2024年第5期595-603,共9页
为探究缺陷与焊缝的相对距离和夹角对X65螺旋埋弧焊钢管失效的影响,开展宽板拉伸试验,采用三维数字图像相关法分析轴向拉伸载荷下缺陷到焊缝的距离、缺陷与焊缝的夹角对管道宽板的力学响应和断裂失效行为的影响特征.结果表明:焊缝和缺... 为探究缺陷与焊缝的相对距离和夹角对X65螺旋埋弧焊钢管失效的影响,开展宽板拉伸试验,采用三维数字图像相关法分析轴向拉伸载荷下缺陷到焊缝的距离、缺陷与焊缝的夹角对管道宽板的力学响应和断裂失效行为的影响特征.结果表明:焊缝和缺陷的存在,以及缺陷到焊缝的相对距离和夹角对管道宽板的应变变化和断裂失效行为有影响,且不同的相对距离和夹角对其抗拉强度、应变分布和断裂失效行为的影响程度不同;当缺陷与焊缝的夹角为30°且当缺陷到焊缝的距离为39 mm时,管道宽板的抗拉强度最低、裂纹萌生及断裂失效所需位移载荷最小,此时其承载能力最差,最容易断裂失效. 展开更多
关键词 油气管道安全 含缺陷宽板 宽板拉伸 数字图像相关法 力学响应 断裂失效
下载PDF
基于激光点云的中厚板表面平整度测量
11
作者 时浩 邓高旭 +2 位作者 李正楠 王荣军 马立东 《光学精密工程》 EI CAS CSCD 北大核心 2024年第16期2464-2473,共10页
在冶金行业中,中厚板是主要产品之一,其平整度是评估钢板质量的重要指标。压力矫平现场还依赖于人工测量,无法准确地表征板材平整度。为了提高检测的准确度及高效性,提出了一种基于机器视觉的平整度测量方法。基于高精度的三维视觉扫描... 在冶金行业中,中厚板是主要产品之一,其平整度是评估钢板质量的重要指标。压力矫平现场还依赖于人工测量,无法准确地表征板材平整度。为了提高检测的准确度及高效性,提出了一种基于机器视觉的平整度测量方法。基于高精度的三维视觉扫描技术,结合高斯拟合算法,利用高斯系数构建特征值,建立高斯特征值与实际板材弯曲高度的映射关系,构建基准平面,计算点云坐标值与基准平面的距离,结合RGB颜色模型绘制板形云图,在此基础上给出压力矫平添加垫板的位置。实验表明,所提出的方法计算误差不大于0.3 mm,可以实现对中心凸起或边缘翘曲钢板的测量,同时板形云图反映了板形分布状况及垫板位置。该度量方法可以准确测量中厚板的弯曲量,可以为压力矫平提供数据支持。 展开更多
关键词 激光点云 板形检测 平整度 高斯拟合 映射
下载PDF
基于服装CAD制版的服装款式快速转化方法
12
作者 张茜 高燕磊 +1 位作者 瞿颖 茅丹 《毛纺科技》 CAS 北大核心 2024年第8期48-57,共10页
针对目前市场上裙装款式种类多,且在CAD制版实践中不同款式相关性弱而导致制版效率低的问题,通过分析裙装款式分类现状制定出裙装款式CAD制版再生成设计路径。研究不同裙装领子、袖子和半身裙制版实例,多维度厘清不同裙装款式相关性,并... 针对目前市场上裙装款式种类多,且在CAD制版实践中不同款式相关性弱而导致制版效率低的问题,通过分析裙装款式分类现状制定出裙装款式CAD制版再生成设计路径。研究不同裙装领子、袖子和半身裙制版实例,多维度厘清不同裙装款式相关性,并采用CLO3D虚拟制衣实验,总结出领子、袖子和半身裙模块化制版参数,实现CAD制版的服装款式快速转化。研究不同裙装款式利用CAD系统提高制版效率的技巧,提出不同裙装版型转换的理念与方法,为高效使用服装CAD制版提供理论支持和设计方法。 展开更多
关键词 ET服装CAD系统 CLO3D虚拟制衣 版型转换 裙装款式相关性 裙装款式再生成
下载PDF
基于比例特征的区域分割算法在药板缺陷检测中的研究
13
作者 颜培鑫 黄海龙 +1 位作者 冷奎 杨泽宇 《包装工程》 CAS 北大核心 2024年第1期208-214,共7页
目的为解决铝塑泡罩药板图像ROI区域定位慢、精度差等问题,本文提出一种基于比例特征的泡罩区域分割算法,该算法可以快速定位并分割泡罩ROI区域,结合图像相关性特征算法对铝塑泡罩药板进行缺陷检测。方法首先通过工业相机采集药品包装... 目的为解决铝塑泡罩药板图像ROI区域定位慢、精度差等问题,本文提出一种基于比例特征的泡罩区域分割算法,该算法可以快速定位并分割泡罩ROI区域,结合图像相关性特征算法对铝塑泡罩药板进行缺陷检测。方法首先通过工业相机采集药品包装生产线上的药板原始图像,接着使用Blob分析从原始图片中分离出铝塑泡罩主体部分,然后通过仿射变换将图像放置在中心区域,并使用比例特征分割算法对泡罩区域进行分割,最后通过金字塔加速的NCC算法完成缺陷检测。结果实验结果表明,基于比例特征分割后的图像平均NCC匹配时间为9 ms,在缺陷样本占比20%的实验中误检率为0.167%,漏检率为0.556%。结论通过比例特征分割出精准的泡罩ROI区域结合改进的NCC算法,在拥有较高准确率的同时大幅减少了缺陷检测时图像匹配的时间,能较好地完成铝塑泡罩药板的缺陷检测任务。 展开更多
关键词 铝塑泡罩药板 比例特征 缺陷检测 归一化互相关
下载PDF
板壳式热交换器内制冷剂R410A蒸发传热性能研究
14
作者 王乙为 王思琦 +2 位作者 叶晶 栾辉宝 阮应君 《石油化工设备》 CAS 2024年第6期1-7,共7页
通过实验研究了板壳式热交换器内制冷剂R410A的蒸发传热特性,分析了饱和温度、质量流率和平均干度对蒸发传热系数及两相摩擦压降的影响。将实验数据与现有的蒸发传热预测模型进行比较,拟合得到了板壳式热交换器内R410A蒸发传热努塞尔数... 通过实验研究了板壳式热交换器内制冷剂R410A的蒸发传热特性,分析了饱和温度、质量流率和平均干度对蒸发传热系数及两相摩擦压降的影响。将实验数据与现有的蒸发传热预测模型进行比较,拟合得到了板壳式热交换器内R410A蒸发传热努塞尔数和摩擦因数的关联式。研究结果表明,R410A的蒸发传热系数随平均干度的增大先增大后减小,随质量流率的增大而增大,随饱和温度的升高而减小。两相摩擦压降随平均干度、质量流率的增大而增大,随饱和温度的升高而减小。R410A努塞尔数、摩擦因数的关联式计算值与实验值的平均误差绝对值分别为3.78%、4.08%。 展开更多
关键词 板壳式热交换器 制冷剂 蒸发 传热系数 摩擦压降 关联式
下载PDF
三大城市群经济增长空间关联网络分析 被引量:1
15
作者 周小孟 刘琼慧 《中国商论》 2024年第2期27-30,共4页
本文研究对象为长三角城市群、京津冀城市群和珠三角城市群,借助格兰杰因果检验及网络分析法,对比分析了2000—2020年三大城市群经济增长空间关联网络的关联关系和关联特征,并分析了各城市群内部的动力传导机制。主要结论有:(1)三大城... 本文研究对象为长三角城市群、京津冀城市群和珠三角城市群,借助格兰杰因果检验及网络分析法,对比分析了2000—2020年三大城市群经济增长空间关联网络的关联关系和关联特征,并分析了各城市群内部的动力传导机制。主要结论有:(1)三大城市群内部各城市之间的经济增长空间关联程度都不高;(2)长三角城市群拥有最为完整的板块分布,珠三角城市群、京津冀城市群板块分布分别为双溢出双受益、三溢出一受益;(3)长三角城市群和京津冀城市群增长原动力为“资本溢出型”,而珠三角城市群的增长原动力为“劳动溢出型”。 展开更多
关键词 网络分析法 空间关联网络 动力传导机制 板块分布 三大城市群
下载PDF
汽车综合耐久试验和强化腐蚀试验腐蚀相关性研究
16
作者 王文涛 崔永瑞 +2 位作者 边帅 吴泽勋 王庐 《环境技术》 2024年第1期99-102,115,共5页
本文期望通过研究汽车综合耐久试验与强化腐蚀试验工况环境下的腐蚀相关性,找到整车综合耐久试验和整车道路强化腐蚀试验工况环境下的腐蚀当量关系,进而评估综合耐久试验车辆和实际用户车辆的腐蚀相关性,用来指导汽车产品设计验证开发。
关键词 综合耐久 强化腐蚀 相关性 标准腐蚀钢板 腐蚀深度
下载PDF
TC4钛合金板数字图像相关的受力成形破坏研究
17
作者 马时凯 王立忠 +1 位作者 付白强 张振 《机械设计与制造》 北大核心 2024年第6期234-238,共5页
为了探究TC4钛合金板成形过程中因受尖顶力作用产生的应力集中导致板材破裂的问题。分别在常温(20℃)和100℃下,采用尖顶顶头对0.5mm厚宽120mm和宽70mm的TC4钛合金试件分别进行成形-破坏试验,利用数字图像相关法(DIC)对钛合金板材的整... 为了探究TC4钛合金板成形过程中因受尖顶力作用产生的应力集中导致板材破裂的问题。分别在常温(20℃)和100℃下,采用尖顶顶头对0.5mm厚宽120mm和宽70mm的TC4钛合金试件分别进行成形-破坏试验,利用数字图像相关法(DIC)对钛合金板材的整个成形-破坏过程进行图像采集,通过匹配计算获取钛合金板材在整个过程中的全场位移和应变云图以及相关数据,并对获取的数据进行对比分析。实验结果显示:TC4钛合金在破裂前一刻位移Y的变化趋势在垂直方向上呈现出明显的非对称性,而位移X、位移Z,位移则呈现出近似同心圆的形状;通过对获取的数据进行分析,证明温度会影响试件的应变分布;常温下破裂前一刻应变云图近似对称分布,而100℃下应变云图沿中心垂直方向呈现非对称分布。该实验为后续对TC4钛合金板材的受力分析,位移应变研究提供了有效参考。 展开更多
关键词 TC4钛合金板材位移测量 温度 数字图像相关法 成形破坏实验
下载PDF
扬子板块石炭纪沉积层序及其全球性对比研究 被引量:29
18
作者 李儒峰 刘本培 赵澄林 《沉积学报》 CAS CSCD 北大核心 1997年第3期23-28,共6页
通过对石炭纪扬子板块内部、扬子板块与华北板块及扬子板块与欧美板块之间的不同级别沉积层序对比研究,编制了扬子板块、华北板块和欧美板块石炭纪的海平面变化曲线。在扬子板块内部,上、下扬子区2级沉积层序可以进行对比,但下扬子... 通过对石炭纪扬子板块内部、扬子板块与华北板块及扬子板块与欧美板块之间的不同级别沉积层序对比研究,编制了扬子板块、华北板块和欧美板块石炭纪的海平面变化曲线。在扬子板块内部,上、下扬子区2级沉积层序可以进行对比,但下扬子区海进和海岸上超滞后于上扬子区,由于资料的限制,3级沉积层序的对比还有困难;华北板块Fusulina-Fusulinela带内的一个3级沉积层序和Triticites-Peudoschwagerina带内的四个3级沉积层序,可以和扬子板块同期的3级沉积层序对比;扬子板块和北美中大陆不仅3级沉积层序可以对比,而且在晚石炭世Gzhelian期4级沉积层序也可以进行对比,但由于它们大地构造背景的差异,导致沉积层序组成内容的不同。上述对比结果被认为是冰川型全球海平面变化所形成全球沉积记录同时性的证据。并以冰期与非冰期、联合古陆形成前后等方面对相同板块内和不同板块间沉积层序的数量和级别的异同原因进行了探讨,认为石炭纪冈瓦纳大陆冰川消长是控制全球海平面变化的主要因素,因此,沉积层序应具全球同时性和可对比性,但局部沉积条件差异也将影响沉积层序组成。 展开更多
关键词 石炭纪 扬子板块 华北板块 沉积层序 全球性对比
下载PDF
板式换热器传热和阻力特性的实验研究 被引量:36
19
作者 徐志明 郭进生 +2 位作者 郭军生 黄兴 张仲彬 《热科学与技术》 CAS CSCD 2010年第1期11-16,共6页
利用搭建的液-液型板式换热器试验平台,根据实验数据运用定性雷诺数法拟合出传热关联式,找出Nu与摩擦因子f之间的通用关系式,为板式换热器的设计计算提供了依据。运用传热量与功率的消耗比来评价板式换热器的性能,找出了影响其性能的主... 利用搭建的液-液型板式换热器试验平台,根据实验数据运用定性雷诺数法拟合出传热关联式,找出Nu与摩擦因子f之间的通用关系式,为板式换热器的设计计算提供了依据。运用传热量与功率的消耗比来评价板式换热器的性能,找出了影响其性能的主要因素,进一步澄清了单纯依靠提高流速来增加传热性能是不经济的。 展开更多
关键词 板式换热器 传热关联式 有效度
下载PDF
“磨拉石建造”和“不整合”在地层对比中的意义:以扬子地块及其北缘… 被引量:36
20
作者 周鼎武 董云鹏 《地质论评》 CAS CSCD 北大核心 1996年第5期416-423,共8页
扬子地块及其北缘晚前寒武纪地层划分对比争议较大,主要是对“地层不整合”和“磨拉石建造”存在认识上的分岐,笔者据现代构造理论,对地壳变形和沉积建造的控制作用认为,地导整合可以发育在被动大陆边缘形成初始阶段的裂谷期和裂谷... 扬子地块及其北缘晚前寒武纪地层划分对比争议较大,主要是对“地层不整合”和“磨拉石建造”存在认识上的分岐,笔者据现代构造理论,对地壳变形和沉积建造的控制作用认为,地导整合可以发育在被动大陆边缘形成初始阶段的裂谷期和裂谷期后,又可产生造山作用过程;磨拉石建造应按构造动力学背景划分为拉张型,挤压型和剪切型三类;它们分别代表了威尔逊旋回不同阶段的产物。 展开更多
关键词 磨拉石 地层不整合 地层对比 扬子地块 寒武纪
下载PDF
上一页 1 2 9 下一页 到第
使用帮助 返回顶部