Extensional Tectonic System of Erlian Fault Basin Group and Its Deep Background

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Reddening of dune sands—evidence from southeast India

Thin section, SEM, and TEM analyses have indicated that the red ‘teri’ sands of southeast India have formed from weathering in situ of coastal dune sands. The data does not support a detrital origin for the red sands. C¹⁴ dates indicate that dune deposition and weathering, to a maximum depth of 10 m, leading to the formation of a hematite, koalinite and illite rich matrix has taken place rapidly over the past 25,000 years. It is postulated that garnet was a major source of hematite (ferric oxide).     

Importance of footing–soil separation on dynamic stiffness of piled embedded footings

Different phenomena such as soil consolidation, erosion, and scour beneath an embedded footing supported on piles may lead to loss of contact between soil and the pile cap underside. The importance of this separation on the dynamic stiffness and damping of the foundation is assessed in this work. To this end, a numerical parametric analysis in the frequency domain is performed using a rigorous three‐dimensional elastodynamic boundary element–finite element coupling scheme. Dimensionless plots relating dynamic stiffness functions computed with and without separation effects are presented for different pile–soil configurations. Vertical, horizontal and rocking modes of oscillation are analyzed for a wide range of dimensionless frequencies. It is shown that the importance of separation is negligible for frequencies below those for which dynamic pile group effects start to become apparent. Redistribution of stiffness contributions between piles and footing is also addressed. Copyright © 2009 John Wiley & Sons, Ltd.     

Lie group variational integrators for the full body problem in orbital mechanics

Equations of motion, referred to as full body models, are developed to describe the dynamics of rigid bodies acting under their mutual gravitational potential. Continuous equations of motion and discrete equations of motion are derived using Hamilton’s principle. These equations are expressed in an inertial frame and in relative coordinates. The discrete equations of motion, referred to as a Lie group variational integrator, provide a geometrically exact and numerically efficient computational method for simulating full body dynamics in orbital mechanics; they are symplectic and momentum preserving, and they exhibit good energy behavior for exponentially long time periods. They are also efficient in only requiring a single evaluation of the gravity forces and moments per time step. The Lie group variational integrator also preserves the group structure without the use of local charts, reprojection, or constraints. Computational results are given for the dynamics of two rigid dumbbell bodies acting under their mutual gravity; these computational results demonstrate the superiority of the Lie group variational integrator compared with integrators that are not symplectic or do not preserve the Lie group structure.     

丹凤地区刘岭群倒转变质带及其地质意义

根据变质矿物组合和变质带的特征,结合变形构造研究,认为丹凤地区的刘岭群曾遭受过中压相系的变质作用,随后又被褶皱及剪切推覆作用改造,使变质带倒转、变薄。文章认为,本区刘岭群在时代上不能与西部邻区的中泥盆统地层对比。     

河南省嵩县大石门沟钼矿床地质特征及找矿前景

河南省嵩县大石门沟钼矿是河南省核工业地质局近年发现并正在进行工作的矿产地,已基本查明为大型钼矿床,初步认为是受隐爆角砾岩体控制的热夜型钼矿床。钼矿体产于隐爆角砾岩体内,矿体形态为大脉状、规模大。文章在系统阐述该矿地质特征和成矿地质条件的基础上,对其找矿远景进行了初步分析。     

小秦岭地区金矿成矿机理分析

小秦岭成矿带是我国重要的贵金属成矿带之一,金矿受地层、构造和岩浆岩控制,具有＂三位一体＂的成矿模式。太古宙太华群地层为成矿提供了物质基础,区域变质作用使金发生初次富集;早期自北而南的挤压形成规模巨大的推覆构造为含金石英脉的生成提供了有利空间;燕山期构造—岩浆活动对金的活化、迁移、富集起主导作用     

济宁岩群大量变质碎屑岩和碳质岩的发现及地层划分

在详细研究济宁市颜店铁矿区报告和以往资料的基础上,对济宁颜店铁矿部分钻孔济宁岩群的岩矿心进行了编录和系统取样工作,发现济宁岩群存在大量变碎屑岩和首次在钻孔中辨别出碳质岩,这对济宁岩群地层的研究和铁矿成矿作用的研究都提供了重要最新资料。对于铁矿的成因研究和原岩及沉积环境的恢复都有重大的意义。依据岩石组合特征和含矿性,济宁岩群自下而上可划分为翟村组、颜店组和洪福寺组。     

南极菲尔德斯半岛潮间带沉积物细菌的多样性及分离菌产酶测定

摘要:南极菲尔德斯半岛具有多种不同特征的生态地理微环境,如长城科考站、企鹅岛、生物湾与黄金湾流域、半岛南部、碧玉滩等。这些区域因水文地质、动植物分布、人类活动程度等不同而具有明显的生态地理差异。本研究从这些微环境海岸潮间带采集了7份代表性沉积物样品,采用16S rRNA基因高通量测序方法,对其细菌类群的多样性以及环境理化因子的影响进行了比较分析;同时采用常规可培养鉴定方法,对样品的分离菌株产酶状况进行了初步测定。结果表明：整体上看,所有样品的细菌类群主要分布在45门、104纲、442属当中,表现出比较高的多样性。其中,优势菌门Proteobacteria主要分布在半岛南部、碧玉滩和生物湾潮间带沉积物物中,优势菌门Bacteroidetes主要分布在企鹅岛两侧和黄金湾潮间带沉积物,长城站潮间带沉积物的优势门为Firmicutes。相似生态微环境的潮间带沉积物具有不同的优势菌门和纲;而不同生态微环境潮间带沉积物却具相同的优势菌门和纲。有机氮（TON）、NH4+-N、NO3--N、PO43--P、NO2--N含量与企鹅岛两侧、生物湾、黄金湾潮间带沉积物的菌群多样性具有相关性,其中TON对生物湾样品的影响最大,而有机碳（TOC）对所有样品的影响较小。分离菌株的产酶实验表明：在企鹅岛、生物湾、黄金湾等动物频繁出没的潮间带样品中,蕴藏着一批产淀粉酶、酪蛋白酶、脂肪酶、七叶苷酶、过氧化氢酶能力较强菌株,这为今后进一步的应用开发提供了宝贵的低温产酶菌株来源。 关键词: 菲尔德斯半岛; 潮间带沉积物; 细菌类群多样性; 产酶菌株     

Blondel和k-核分解混合算法相结合的网络空间点群要素多尺度模型构建

随着人们对网络空间的依赖性不断增强,互联网技术与网络基础设施规模迅速发展。很难直接用数字或表格的形式对网络空间进行全局的规划与管理,并且不容易发现隐藏在网络空间中的一些关键信息。网络空间点群要素的多尺度模型构建对网络空间数据的多尺度分析和可视化具有非常重要的意义。本文以网络空间的特征为依据,在借鉴基于社团划分的网络空间分层算法和基于节点重要性的网络空间分层算法特点的基础上,提出了Blondel算法和k-核分解的混合算法相结合的网络空间点群要素多尺度模型构建算法。本算法通过自动社团划分,用同一社团内的节点合并构建新的网络,有效解决了基于节点重要性的网络空间分层算法自动化程度低的弊端。利用核心节点来代替整个社团结构,显著保留了网络空间中节点的属性。实验表明使用该算法可以使各个层次网络空间点群要素的综合比例降至30%以下,较好的实现了网络空间点群要素的聚类与分层,若将网络空间点群要素的多尺度模型应用于地理空间中,则可实现网络空间地图的多尺度绘制。