New measurement of melting and thermal conductivity of iron close to outer core conditions     

Abhisek Basu  Matthew RField  Dougal GMcCulloch  Reinhard Boehler 《地学前缘(英文版)》2020,(2):565-568

The amount of literature on both melting and thermal conductivity of iron at Earth’s core conditions is overwhelming and the discrepancies are very large.There is a broad range of experimental techniques each of which is flawed to a certain degree,which may explain the discrepancy.In this report,we present new data using a different method for determining the phase behavior and resistivity of iron in the laser-heated diamond cell by measuring the electrical resistance of both solid and liquid iron wires.The experiment avoids some of the major flaws of previous experiments,the most important of which is the detection of the onset of melting.These measurements confirm a shallow melting curve found earlier and the resistivity data imply a trend towards low thermal conductivity in the liquid outer core.  相似文献   

Preliminary study on strontium-rich characteristics of shallow groundwater in Dingtao Area,China          下载免费PDF全文

CAO Yan-ling  SONG Liang  LIU Lian  ZHU Wen-feng  CUI Su  WANG Yan-ting  GUO Peng 《地下水科学与工程》2020,8(3):244-258

Based on the analysis of element correlation, the Gibbs diagram, hydro-geochemical ion ratios, isoline maps of groundwater and soil, and change patterns of strontium content after normalization, the study examines water-rock interaction of shallow groundwater in Dingtao area. The results suggest that strontium in the study area mainly comes from water-rock interactions, and the strata interacting with groundwater are the top of Quaternary and Neogene. The element correlation analysis shows that the formation of strontium-rich groundwater is sufficiently affected by sulfate and carbonate. The Gibbs diagram suggests that the chemical composition of groundwater is mainly influenced by water-rock interactions, accompanied by evaporation crystallization. c(Ca²⁺+Mg²⁺)/c(HCO₃^-+SO₄^2-) reflects that the main reactions in the groundwater system is weathering dissolution of carbonate and sulfate, and ion exchange takes place. c(Na⁺)/c(Cl^-) indicates that Na⁺ in groundwater may have water-rock interactions with rocks it flows through. c(Cl^-)/c(Ca²⁺) indicates that the hydrodynamic condition in the pumping well is poor and the water circulation is slow. The study examines the macro isoline map change patterns, correlation curves of change of strontium content in groundwater and shallow soil, and correlation curves of change of strontium content in groundwater, shallow soil, and deep soil. The results suggest that the strontium content in the study area has the same change pattern in groundwater and in soil, which further indicates that strontium in the study area comes from water-rock interactions.  相似文献   

一种基于Voronoi多边形的海底底质表示方法     

张莉  王义涛  陈跃  张立华 《海洋技术学报》2008,27(2):105-108

海底底质对舰船航行、锚泊、登陆、铺设海底管线等海上活动具有重要的影响。文中提出了一种基于同质Voronoi多边形的海底底质分布可视化方法。通过构建Delaunay三角网,求取Voronoi多边形顶点,并依次排序顶点,从而生成构成Voronoi图。在Voronoi图的基础上,提出了同底质Voronoi多边形合并的具体算法,并处理与岸线相交的区域。实验表明,文中所提方法对于海底底质分布的可视化表达,比传统方法更为形象、直观。  相似文献   

紧急救援下障碍空间分析技术的应用     

胡海  胡鹏  游涟 《地理信息世界》2008,6(1):39-45

灾害紧急救援提出了对地理信息技术新的急迫要求:即动态GIS中的动态数据模型和"0"初始化计算问题,障碍空间路径规划问题、"安全岛"问题——障碍空间最大(小)间隙问题、与安全区的k阶邻近问题,本文给出了这些问题的解决途径和解算实例。  相似文献   

基于Voronoi图的遥感影像校正地面控制点选取     

周家香  朱晓东  周晓光 《地理信息世界》2007,5(2):67-70

遥感影像几何校正时要求选取的地面控制点应尽可能在整幅影像内均匀分布,而对于均匀分布的理解主观性较强。本文运用Voronoi图控制地面控制点的均匀分布,并建立了控制点的分布与数量的联系,使选取的地面控制点分布均匀,且数量足够。实验证明,用Voronoi图控制地面控制点的均匀分布,是提高遥感影像多项式几何校正精度的有效途径。  相似文献   

基于空间关系的海上应急救援力量调度模型     

张乾  闫浩文  张黎明  何毅 《地球信息科学学报》2018,20(6):772-780

本研究以Voronoi图为研究工具,对普通Voronoi图在海上救援应用中的局限性进行分析,并对其进行了合理改进,提出了“海上救援V图”。同时,结合模糊层次分析法和引力模型方法计算各海事机构救援力量的“吸引力”权重矩阵,提出了基于Voronoi图的海上救援调度模型。最后,结合具体救援案例,构建了基于Voronoi图的海上应急救援模型MRSV。实验结果表明：该模型能够在顾及海上特殊地理环境以及要素间空间关系的基础上,综合考虑各海事机构的救援力量,针对不同海难情况,选调合适的救援机构,调度结果合理,能够达到优化救援力量配置的目的,可以为目前海上应急救援力量调度提供参考。  相似文献   

非平衡非耗散热力学及非平衡相图计算          下载免费PDF全文

王季陶  张卫 《盐湖研究》2003,11(1):62-65

非平衡非耗散热力学是现代热力学中的一个全新领域。该领域的基本情况可参见王季陶的最新英文专著《Nonequilibrium Nondissipative Themodynamics》一书[Springer的网页：http://www.springer.de/egi-bin/search book.pl？isbn=3-540-42802-x]。文中对现代热力学完整的基本分类系统和非平衡相图的计算展开一定的讨论。  相似文献   

Schmidt plate survey in the galactic centre direction. 1. Investigation of open clusters in the Sagittarius-Carina spiral arm     

N. Kharchenko  E. Schilbach 《Astronomische Nachrichten》1995,316(2):91-104

A study of four open clusters on Tautenburg Schmidt plates in the direction to the Galactic Centre (l = 17.0°, b = +0.8°) is presented. In a field of 8.95 square degrees proper motions and B, V magnitudes were determined for about 36 500 stars up to the limiting magnitudes B = 17^m.9, V = 16^m.8. For stars brighter than B = 16^m an accuracy of about 3 mas/year has been estimated for proper motions. The rms errors of stellar magnitudes and (B—V) colours is about 0.1 mag. There are two open clusters already known in this sky area: Trumpler 32 (C 1814-133) and NGC 6611 (C 1816-138). By the inspection of the plates two additional anonymous clusters were identified near the double star ADS 11285 or BD −14°5014 (C 1819-146) and near the star BD −14°5016 (C 1820-146). The cluster membership determination was carried out using information on spatial and proper motion distributions of stars in the field. The colour-magnitude diagrams up to the limiting stellar magnitude were constructed. For each cluster interstellar extinction A_V, diameters of the core and corona, ages and spatial velocity components (V, W) relative to the LSR in the Y, Z-galactic directions were derived. The distances to the clusters were obtained to 1720 pc, 2260 pc, 2130 pc and 2130 pc for Trumpler 32, NGC 6611, C 1819-146 and C 1820-146, respectively. All clusters are situated in the Sagittarius-Carina spiral arm. Their spatial location confirms the assumption that galactic spiral arms are close to logarithmic spirals with a characteristic angle of about 20 degrees.  相似文献   

盐田兑卤法提高光卤石矿质量的方法探讨   总被引：1，自引：1，他引：0       下载免费PDF全文

李建国  王成玲 《盐湖研究》2007,15(3):33-36,47

通过相图分析及计算,介绍了一种"由盐湖卤水兑卤除氯化钠后,首先获得成矿卤水,然后对其蒸发制取质量较好光卤石矿"的生产方法。  相似文献