基于地标与Voronoi图的层次化空间认知与空间知识组织

地标提取是空间认知与空间知识组织领域的研究热点之一。显著度量模型作为地标提取的主要方法, 其原理是地物外观、结构与语义的加权评价。顾及地物的空间分布形态和几何特征, 从地物Voronoi图出发, 提出复合Voronoi生长元高度、Voronoi k阶邻域缝隙及Voronoi k阶邻域可视性特征的地标提取方法, 意在探索从个体到邻域的地标几何特征反映。设计实验并与已有方法的提取结果进行对比分析, 验证了方法的有效性;相对于地物属性特征, 由Voronoi图蕴含的几何特征能够有效地表征地标, 降低地标特征选择复杂度。     

高效液相色谱-等离子体质谱技术在溴元素形态分析中的应用

溴是一种在自然水体中都含有的元素,通常以B r-的形式存在。目前最常用的水净化方式就是向水中通入臭氧以杀灭细菌;而臭氧分解的副产物即为B r-转换成的B rO3-,这是一种公认的致癌物质。本实验室曾使用阴离子交换高效液相色谱(HPLC)与等离子体质谱(ICP-MS)联用分析B rO3-和B r-,方法虽能有效地将这两种溴形态分离,但分析每个样品需8 m in。本文试图建立新的方法缩短分析时间,并验证该方法应用于实际水样分析时测定其他含溴化合物的能力。1实验部分1.1高效液相色谱分析条件表1列出了等度淋洗和梯度淋洗两种模式下HPLC的分析条件,完成形态的分离。等度淋洗和梯度淋洗在分析中显示出不同     

地球内核粘滞度的动力学估计

最新的地震学研究指出,地球的内核正在对地球的其余部分作相对旋转。根据数值模拟,这一情形可能是由在液态外核中正在作对流运动的流体所保持。另一方面,由于地幔中质量分布的不均匀,巨大的引力将足以便内核与地幔相匹配。内核的不同旋转会通过在旋转时对自身形状的调整民这些强大的引力保持一致,进面可得出在地球最内部区域内有效粘滞度的一个估计。由推测的旋转率得到的内核粘滞度为小于１０＾１６Ｐａ或大于１０＾２０Ｐａ。     

闽江口外海域MIS 5和MIS 3的地震地层学特征和古环境

通过闽江口外海域进行的高分辨率浅地震剖面(拖筏)调查,揭示了MIS 6末期以来最大厚度约90 m的沉积地层。研究了MIS 5和MIS 3地震层序的反射波结构特征,基于地震相分析识别沉积地貌类型;结合深海氧同位素海平面变化曲线,阐述了两时期研究区的沉积环境、特殊地貌的分布和体系域阶段;最后简要探讨了海侵视强度(视高度)及其影响因素。在MIS 5,研究区主要为滨浅海环境,在MIS 5.3和MIS 5.1局部发育了赛江水下三角洲、潮流沙脊和滨海沙坝等沉积地貌;在初期和低海面亚期为陆相环境,发育了闽江和赛江河道,分别经南部和东北部向东入海(台湾海峡)。在MIS 3,研究区普遍为海水覆盖,以滨浅海环境为主,局部发育闽江水下三角洲叶瓣和潮流沙脊。MIS 5的海平面远高于MIS 3,但是典型地震剖面的研究表明,前者的海侵视强度(视高度)低于后者,推断这一现象主要与构造沉降有关,沉积物压缩也有一定的影响,这也可以解释南部海区MIS 5.2的古闽江河道要远低于当时海平面的现象。     

Seasonal distribution of rainfall in Australia analysed by Fourier methods

Summary A harmonic or Fourier analysis of mean monthly rainfall data is found useful in objectively describing and mapping the seasonality of rainfall within Australia. Over large areas the seasonal component is well described by the first and second harmonic terms, leaving as a residual variance only a small proportion of the observed total variance. Care must be taken in the interpretation of second harmonic contributions within those areas of tropical Australia under strong monsoonal influences. This is because pecularities in the form of the annual rainfall regime make the first harmonic term inadequate in itself to fully describe the annual trend. The technique is found particularly useful in defining the boundaries of areas of similar seasonality, and maps based upon the first and second harmonic amplitudes are shown to bear a close relationship with known physical controls.

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Zusammenfassung Zur objektiven Beschreibung der jahreszeitlichen Schwankung der Regenfälle in Australien und ihrer kartenmäßigen Darstellung wird mit Erfolg die harmonische Analyse der mittleren Monatsmengen des Niederschlags angewendet. Über weiten Gebieten wird die jahreszeitliche Schwankung durch die ersten beiden harmonischen Schwingungen gut dargestellt; die Reststreuung macht nur einen kleinen Bruchteil der beobachteten Gesamtstreuung aus. Vorsicht erscheint jedoch geboten bei der Interpretation des Anteils der zweiten Harmonischen in den Gebieten des tropischen Australien, die unter starkem Monsuneinfluß stehen. Hier machen Besonderheiten im Niederschlagsregime selbst die erste Harmonische ungenügend zur Beschreibung des Jahresganges. Die angewandte Methode ist besonders geeignet, die Grenzen zwischen Gebieten mit gleichartigem Jahreszeiteneinfluß festzulegen. Karten, die auf der ersten und zweiten harmonischen Schwingung beruhen, zeigen einen engen Zusammenhang mit bekannten physikalischen Faktoren.

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Résumé Afin de décrire objectivement les variations saisonnières des précipitations en Australie, on se sert avantageusement de l'analyse harmonique des sommes mensuelles moyennes. Cette méthode est également utilisée pour la représentation cartographique des dites variations. Les amplitudes saisonnières sont bien rendues par les deux premières harmoniques et cela pour de grandes étendues. L'amplitude qui reste ne représente qu'une faible fraction de l'amplitude totale observée. Il faut cependant procéder avec prudence lors de l'interprétation de la part revenant à la seconde harmonique dans les contrées tropicales de l'Australie, contrées qui subissent fortement l'influence de la mousson. Dans ce cas précis, les particularités du régime des précipitations ne permettent même pas d'utiliser la première harmonique pour décrire l'évolution des pluies au cours de l'année. La méthode proposée est surtout intéressante pour délimiter les régions soumises aux mêmes régimes. Des cartes basées sur la première et la seconde harmonique montrent un rapport étroit entre les précipitations et certains facteurs physiques connus.

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Soil–pile–structure interaction: experimental outcomes from shaking table tests

An effective way to study the complex seismic soil‐structure interaction phenomena is to investigate the response of physical scaled models in 1‐g or n‐g laboratory devices. The outcomes of an extensive experimental campaign carried out on scaled models by means of the shaking table of the Bristol Laboratory for Advanced Dynamics Engineering, University of Bristol, UK, are discussed in the present paper. The experimental model comprises an oscillator connected to a single or a group of piles embedded in a bi‐layer deposit. Different pile head conditions, that is free head and fixed head, several dynamic properties of the structure, including different masses at the top of the single degree of freedom system, excited by various input motions, e.g. white noise, sinedwells and natural earthquake strong motions recorded in Italy, have been tested. In the present work, the modal dynamic response of the soil–pile–structure system is assessed in terms of period elongation and system damping ratio. Furthermore, the effects of oscillator mass and pile head conditions on soil–pile response have been highlighted, when the harmonic input motions are considered. Copyright © 2015 John Wiley & Sons, Ltd.     

Nature, origin and evolution of the granitoid-hosted early Proterozoic copper-molybdenum mineralization at Malanjkhand, Central India

At Malanjkhand, Central India, lode-type copper (-molybdenum) mineralization occurs within calcalkaline tonalite-granodiorite plutonic rocks of early Proterozoic age. The bulk of the mineralization occurs in sheeted quartz-sulfide veins, and K-silicate alteration assemblages, defined by alkali feldspar (K-feldspar ≫ albite) + dusty hematite in feldspar ± biotite ± muscovite, are prominent within the ore zone and the adjacent host rock. Weak propylitic alteration, defined by albite + biotite + epidote/zoisite, surrounds the K-silicate alteration zone. The mineralized zone is approximately 2 km in strike length, has a maximum thickness of 200 m and dips 65°–75°, along which low-grade mineralization has been traced up to a depth of about 1 km. The ore reserve has been conservatively estimated to be 92 million tonnes with an average Cu-content of 1.30%. Supergene oxidation, accompanied by limited copper enrichment, is observed down to a depth of 100m or more from the surface. Primary ores consist essentially of chalcopyrite and pyrite with minor magnetite and molybdenite. δ³⁴S (‰) values in pyrite and chalcopyrite (−0.38 to +2.90) fall within the range characteristic of granitoid-hosted copper deposits. δ¹⁸O (‰) values for vein quartz (+ 6.99 to +8.80) suggest exclusive involvement of juvenile water. Annealed fabrics are common in the ore. The sequence of events that led to the present state of hypogene mineralization is suggested to be as follows: fracturing of the host rock, emplacement of barren vein quartz, pronounced wall-rock alteration accompanied by disseminated mineralization and the ultimate stage of intense silicification accompanied by copper mineralization. Fragments of vein quartz and altered wall rocks and striae in the ore suggest post-mineralization deformation. The recrystallization fabric, particularly in chalcopyrite and sphalerite, is a product of dynamic recrystallization associated with the post-mineralization shearing. The petrology of the host rocks, hydrothermal alteration assemblages, ore mineral associations, fluid inclusions and the sulfur and oxygen isotopes of ores are comparable to those in Phanerozoic (and reported Precambrian) porphyry-copper systems, and the Malanjkhand deposit has important implications for both metallogenic models for, and mineral exploration in, Precambrian terrains.