川东南—黔中及其周边地区下组合烃源岩元素地球化学特征及沉积环境意义

笔者采用ICP-MS测试分析技术,对川东南-黔中及其周边地区震旦-志留纪地层28件样品进行了B、V、Ni、Sr、Ba、Th、U等指示沉积环境的敏感微量元素做了系统测试分析,采用GB/T14506.28-93硅酸盐岩石化学分析方法和X射线荧光光谱法测定主要元素和微量元素含量,并探讨了Sr/Ba、V/Ni、V/(V+Ni)、Sr/Ca、Ca/Mg、Th/U比值与沉积环境的对应关系.分析结果表明,本区下组合沉积环境主要为半深海、深海及浅海滞流环境.元素空间分布的差异性反映了沉积环境的区域性变化.     

复杂条件下烟囱控制爆破拆除方法研究

以三门峡市渑池县化工厂70m高烟囱定向爆破拆除为例,针对在复杂条件下烟囱控制爆破拆除方案的选择,爆破切口、定向窗的设计,爆破参数的选取进行了研究,可为复杂条件下烟囱控制爆破拆除提供参考。     

金沙龙凤煤矿测井曲线特征及其在煤岩层对比中的应用

龙凤煤矿含煤地层为海陆交互相的上二叠统龙潭组,含4号、5号、9号和13号四层可采煤层,其中5号煤层和9号煤层间距较小,煤层特征差异不明显,部分钻孔5号煤层和9号煤层的对比难度较大。根据所掌握的地质资料,结合测井成果,总结出该矿区所特有的测井曲线特征：煤系地层龙潭组的上覆地层夜郎组和长兴组分界处自然伽马和视电阻率曲线界面陡直特征;5号煤层顶板的自然伽马高异常与9号煤层底板的自然伽马高异常特征;13号煤层顶板的自然伽马高异常与15号煤层相对高自然伽马异常特征;15号煤层下伏地层茅口灰岩陡直视电阻率与自然伽马曲线特征。依据其测井曲线,准确的划分出二较厚煤层（约4m）、而相距仅6m的5煤层与9煤层。     

Opening and closing process of the Paleo-Tethys in Northern Thailand

The Paleo-Tethys formed a large ocean basin that existed between Laurasia and Gondwana during Late Paleozoic to Early Mesozoic times. It opened in the Early Devonian by the rifting of Gondwanaland and closed at around latest Triassic time by the collision of the Cimmerian continent to Laurasia (Metcalfe, 1999). We reconstructed opening and closing process of the Paleo-Tethys in Northern Thailand.     

土工织物加筋体在提高路堤稳定性方面的应用

加筋技术在地基处理过程中的应用已经广泛应用,加筋作用原理、应力传递和加筋作用机理的研究与工程应用已经日趋成熟,就路基填筑的填筑材料特性、路基碾压施工特点及路基的断面形式,结合土工织物的筋材性状,对路基填筑中的加筋技术进行了设计与检算,并且提出了施工坡面防护措施。     

铜石杂岩体隐爆作用与金矿成矿的关系及其研究意义

山东省平邑县铜石地区是鲁西最重要的金矿产地,继归来庄大型金矿床发现之后,又相继发现了卓家庄特富金矿床及磨坊沟、梨方沟、贺山庄等具层控特征的金矿床,构成了铜石金矿田。这些金矿床的形成与铜石地区中生代多期次岩浆活动或隐爆作用密切相关,分布于岩体边部的隐爆-侵入角砾岩是金矿床的载体,成为寻找隐爆-侵入角砾岩型金矿的重要标志。     

Generating hierarchical strokes from urban street networks based on spatial pattern recognition

Strokes are products of a higher-level aggregation of street segments that can reflect functional importance and perceptual significance that is associated with them in human spatial mental conceptualizations, which is of vital importance for network analysis, street selection, and map generalization. Street properties (e.g., street names) and angles between street segments are the two main elements used for generating street strokes according to the continuity principle of perceptual grouping into networks. However, it is difficult to automatically generate strokes with good continuity from street networks with multiple lanes such as dual carriageways or complex street junctions. This article proposes a method for generating street strokes that maintain good continuity across multiple lanes and complex street junctions. The proposed method first detects dual carriageways and complex junctions in street networks and then generates strokes according to the continuity principle of perceptual grouping. Finally, it groups the generated street strokes across the dual carriageways and complex street junctions to maintain good continuity. Moreover, the generated strokes are hierarchically ranked based on stroke length and centrality measurements. Experimental studies demonstrate the validity and effectiveness of the proposed method. The result shows that the generated street strokes maintain good continuity and reflect well the hierarchical structure of the street networks.     

On the scavenging of SO2 by cloud and raindrops: II. An experimental study of SO2 absorption and desorption for water drops in air

For the purpose of testing our previously described theory of SO₂ scavenging a laboratory investigation was carried out in the UCLA 33 m long rainshaft. Drops with radii between 250 and 2500 m were allowed to come to terminal velocity, after which they passed through a chamber of variable length filled with various SO₂ concentrations in air. After falling through a gas separating chamber consisting of a fluorocarbon gas the drops were collected and analyzed for their total S content in order to determine the rate of SO ₂ absorption.The SO₂ concentration in air studied ranged between 1 and 60% (v). Such relatively large concentrations were necessary due to the short times the drops were exposed to SO₂ in the present setup. The present experimental results were therefore not used to simulate atmospheric conditions but rather to test our previously derived theory which is applicable to any laboratory or atmospheric condition. Comparison of our studies with the results from our theory applied to our laboratory conditions led to predicted values for the S concentration in the drops which agreed well with those observed if the drops had radii smaller than 500 m. In order to obtain agreement between predicted and observed S concentrations in larger drops, an empirically derived eddy diffusivity for SO₂ in water had to be included in the theory to take into account the effect of turbulent mixing inside such large drops.In a subsequent set of experiments, drops initially saturated with S (IV) were allowed to fall through S-free air to determine the rate of SO ₂ desorption. The results of these studies also agreed well with the results of our theoretical model, thus justifying the reversibility assumption made in our theoretical models.In a final set of experiments, the effects of oxidation on SO₂ absorption was studied by means of drops containing various amounts of H₂O₂. For comparable exposure times to SO₂, the S concentration in drops with H₂O₂ was found to be up to 10 times higher than the concentration in drops in which no oxidation occurred.     

锆石对地球早期地壳演化和构造体制转换的启示

锆石是研究早期地球演化的重要矿物之一,它的U-Pb年龄结合其微量元素以及同位素成分是反演寄主岩石成因乃至地球动力学背景的重要手段.本文从锆石矿物包裹体、微量元素、U-Pb同位素体系、Lu-Hf同位素、O同位素以及Si、Zr和Ti同位素这6个方面综述了近10年来前人取得的主要研究成果,总结了次生矿物包裹体可能产生的方式以...     

Meteor Showers Associated with the Taurid Complex Asteroids

Recent theoretical and observational work has shown that the asteroids belonging to the Taurid meteoroid complex have a cometary nature. If so, then they might possess related meteoroid streams producing meteor showers in the Earth atmosphere. We studied the orbital evolution of ten numbered Taurid complex asteroids by the Halphen-Goryachev method. It turned out that all of these asteroids are quadruple crossers relative to the Earth's orbit. Therefore their proposed meteoroid streams may in theory each produce four meteor showers. The theoretical orbital elements and geocentric radiants of these showers are determined and compared with the available observational data. The existence of the predicted forty meteor showers of the ten Taurid complex asteroids is confirmed by a search of the published catalogues of observed meteor shower radiants and orbits, and of the archives of the IAU Meteor Data Center (Lund). The existence of meteor showers associated with the Taurid Complex Asteroids confirms that, most likely, these asteroids are extinct comets. This revised version was published online in July 2006 with corrections to the Cover Date.