The taxonomical and functional diversity of three groups of aquatic insects in rheocrene karst springs are affected by different environmental factors

Karst springs represent valuable and often the most threatened habitats in the riverine landscape. Unlike other stream habitats, they have several specifics that determine their insularity in the river continuum, e.g., high seasonal thermal and chemical stability. The presented study aimed to find out the taxonomical and functional richness of three groups of aquatic insects (Ephemeroptera, Plecoptera and Trichoptera) in the Western Carpathians karst springs, as well as uncover the mechanism of the EPT community assembly. Low within-site species richness was generally found, however, there was high between-site diversity and thus high total diversity of the studied groups of benthic invertebrates as well. Species richness of the EPT community was higher in larger and colder springs: those with lower concentrations of CO₂ and Fe, as well as higher concentrations of SO₄²⁻. Analysis of functional richness, as well as functional dispersion, did not reveal any clear assembly mechanism in the spring EPT community; however, both analyses indicated a higher proportion of environmental filtering there. Unlike the taxonomic richness, the functional richness of the EPT community was significantly higher in small and medium springs with higher water temperatures, as well as in springs with the presence of deadwood. Between-site dissimilarities in the functional composition of EPT were significantly correlated with environmental differences of springs, which determined variables such as spring size and temperature, as well as the concentration of CO₂ and SiO₂.     

Mesozoic radiolarian chert from the middle sector of the Yarlung Zangbo suture zone,Tibet and its tectonic implications

The middle sector of the Yarlung Zangbo suture zone stretches over 200 km long from Ngamring through Geding to Rinbung, roughly along Yarlung Zangbo River valley (Fig. 1). This belt resulted from the closure of the Tethyan ocean and the collision be- tween Indian plate and Lhasa block[1―8]. Lots of works demonstrated that rifting of the Tethyan basin in southern Tibet started from Triassic time. Initial oce- anic crust appeared in the Late Jurassic, and then ex- perienced a rapid sprea…     

Significance of fossilized microbes from the Cambrian stromatolites in the Tarim Basin,Northwest China

Samples of the Cambrian microbial dolomites were collected from Penglaiba section,a well-exposed stratigraphic section in the northwestern area of the Tarim Basin.This study provides an analogue for mediated dolomites that can precipitate in microbial mats and biofilms.The Cambrian stromatolitic dolomites were studied using high-resolution scanning electron microscopy.The results are as follows:(1)dolomites with 50 nm to 100 nm spherical nanostructures are aggregated into minerals of larger sphericities;(2)nanospherical dolomites of 50 nm to 170 nm diameter are densely arranged as dumbbell-shaped or chained aggregates;(3)silicified filaments,as well as dumbbell-shaped and chain arrangements,are preserved as important microstructures.On the basis of sedimentological,compositional,geochemical,and petrographic data,the microstructures were interpreted as nanoglobules that function as bacteria in the nucleation and filament mineralization stages.The microstructures function as such because they are wrapped in extracellular polymeric substance(EPS)or mucus and mineralized fossils.Silicification accounts for the exceptional preservation of microbial mat structures,including biofilms,as well as filamentous and coccoid microbes.In addition,EPS process is capable of binding different elements,with preference for Si,Mg,and Ca.Such suitable composition favors microbe mineralization and dolomite nucleation on organic substrates.These microscopic structures suggest bacterial mineralization and provide visual evidence for the origin of microbial dolomites.     

Bridge dynamic loading due to road surface irregularities and braking of vehicle

Single span highway bridges of composite construction are idealized as beams as well as orthotropic plates. A standard HS–20–44 highway vehicle is represented by a planar, two-axle, sprung mass system with frictional device. The response equations are derived in terms of the natural modal co-ordinates of the bridge and of displacement co-ordinates of the vehicle. The road surface irregularities, generally found at the junctions of the approach road and bridge ends, are idealized as a 45° ramp. The maximum impact factors for bending moment and deflection are obtained due to the ramp and in combination with the braking of vehicle for symmetric as well as essentric loading of the vehicle.     

纵贯中国东部一条新的巨型构造带

本文从地貌、地质、地球物理和地震活动等方面,论证了一条由地垒、地堑系组成的、纵贯中国东部的巨型活动性深断裂带。 这是一条以张扭性为主、差异升降强烈的追踪断裂带。它控制着沉积岩相、地貌水系和岩浆活动,尤其是作为一条超基性岩带,可为寻找有关矿产提供标志;同时也是一条构造地震带     

Magnetic anisotropy of rocks and its application in geology and geophysics

Magnetic anisotropy in sedimentary rocks is controlled by the processes of deposition and compaction, in volcanic rocks by the lava flow and in metamorphic and plutonic rocks by ductile deformation and mimetic crystallization. In massive ore it is due to processes associated with emplacement and consolidation of an ore body as well as to ductile deformation. Hence, it can be used as a tool of structural analysis for almost all rock types. Morcover, it can influence considerably the orientation of the remanent magnetization vector as well as the configuration of a magnetic anomaly over a magnetized body. For these reasons it should be investigated in palaeomagnetism and applied geophysics as well.     

中国东部地区的地球物理场特征与含油气盆地的分布和形成

本文根据中国东部陆缘地区--郯庐断裂带两侧地壳与上地幔结构和综合地球物理场特征,阐述了其与一串含油气裂谷型盆地的分布规律,并讨论了其沉积和演化。 结果表明:这一系列含油气盆地,分布在上地幔顶部的隆起地区,均具有异常的地球物理场特征。这些盆地中有着巨厚的中、新生代的沉积,具备了良好的生油与储油条件。它们的形成与太平洋板块和欧亚板块的运动密切相关,并且受着深部地幔物质运移的制约。     

Geophysical prospection,archaeological excavation,and dating in two Hellenic pyramids

Geophysical prospection employing magnetometry and electromagnetic measurements has been applied in and around two small sized pyramids of Hellenikon and Ligourio in Argolid, Greece. The magnetic anomalies appropriately assessed were interpreted as possible archaeological targets. Subsequent test excavations revealed the presence of room foundations and parts of walls, as well as a plethora of ceramic ware. Typological study of the ceramics classified them to as early as the proto-Helladic period and to as late as the first centuries A.D. The earlier periods have been also confirmed by a novel application of thermoluminescence (TL) dating of ceramics and the megalithic stones themselves. The present results question earlier attempts classifying these pyramids at the Classical period and favour much earlier periods.     

地层渗透率与水合物含量关系的模拟研究(英文)

本文通过人工变换T2分布和建立管-球模型模拟法研究含水合物地层渗透率与水合物含量之间的关系。首先,在渗透率的模拟试验中,我们改变了束缚水与可动水的比例、总孔隙度以及与之关联的T2分布。试验结果表明,相对渗透率与水合物含量之间的关系受到这些因素的制约。随后,我们用管-球模型表示水合物生长的孔隙空间,并把水合物的生长过程看成是向孔隙空间随机扔小球的过程。在此过程中,采用两种方法计算渗透率,一是Schlumberger’sT2公式(即SDR模型),二是Darcy定律与Poiseuille流动方程相结合的方法。前人的实验研究表明,在一定的水合物含量范围内,渗透率基本保持不变。以此为参考,我们将计算结果与之进行比较。我们发现,采用SDR模型时,渗透率的数值模拟曲线与Masuda模型N=15时的结果相近。而采用Darcy定律时,渗透率模拟值较高,但与实验结果的趋势相一致,都会出现渗透率的平直阶段。尤其,当水合物晶体在孔隙体内优先生成时,优先的概率越高,渗透率的平直范围越大。     

Mining,Environmental, Petroleum,and Engineering Industry Applications of Electromagnetic Techniques in Geophysics

Electromagnetic (EM) techniques are extremely important as a direct detection geophysical tool utilized in the base metal industry. They were developed in countries such as Canada, whose thin conductive weathering overburden did not hamper the penetration of EM signals and enabled exploration to depths on the order of 300 m. As a result, EM techniques were used widely in North America and Scandinavia for many years before they became common in countries with a thick conductive overburden, such as Australia. The 1980s and 1990s have seen the use of EM methods move from anomaly finding to mapping, as well as the development of better, faster and more accurate computer modelling algorithms. A review of EM papers, for the years 1998 to 2002, showed that most dealt with EM techniques as mapping tools. Airborne, ground and marine EM techniques are still being developed, as are data processing and interpretation software. The advent of robust 2-D and 3-D computer modelling and inversion algorithms has led to the acceptance of EM methods as a mapping tool for many environmental and petroleum industry applications, a trend which is expected to increase.     

基于WebGIS的区域震害快速评估系统设计与实现

在进行大规模城乡震害预测工作中,需要使用与传统预测方式不同的新模型及新方法,以便实现震害快速预测及结果共享。利用人口普查数据等基础数据库,根据人口数据及灾害损失的关系模型,基于WebGIS技术,采用三层体系网络架构(由后台数据库、应用服务器(地图服务器)+Web服务器、客户端组成),利用VB+ArcObject服务器组件开发技术,通过动态链接库技术实现了在Ar-cIMS下的地图动态更新、动态预测及动态发布功能,实现了具有B/S结构的震害预测管理信息系统。该系统具有投入少、数据自动预测、定期更新且易于获取等优点,实现了地震震害信息共享     

Calcic anorthosite from the nuggehalli schist belt,Karnataka state,India

Calcic anorthosite with plagioclase of 95 to 100% anorthite content has been discovered by the authors in the Nuggehalli schist belt of Karnataka State, India. It occurs near Jambur as a massive body, boulder in nature, admist talc-chlorite-actinolite-serpentine schist. Zoning exhibited by the plagioclase and the C-Twins are characteristic of their formation in a magmatic environment. Albite rims surrounding Anrich plagioclase indicate depositional zoning, and not the normal zoning as commonly visualised. The early formed plagioclase contained much less soda and, hence, there was a continuous storing up of the soda molecule in the residual liquid which later got precipitated as veins sweeping along grain boundaries and as rims around An-rich plagioclase to form depositional zoning. Sections of calcic anorthosite with plagioclase of all An percentage were encountered. They present evidences of differentiation within highly localised zones, as narrow as the size of a thin section. It is suggested here that the calcic anorthosite originated as a result of differentiation, that is, by the segregation of anorthite plagioclase from a gabbroic magma and that it came up along the central part of the rift as a post-tectonic intrusive body.     

Exponential data fitting applied to infiltration, hydrograph separation, and variogram fitting

Most lumped rainfall-runoff models separate the interflow and groundwater components from the measured runoff hydrograph in an attempt to model these as hydrologic reservoir units. Similarly, rainfall losses due to infiltration as well as other abstractions are separated from the measured rainfall hyetograph, which are then used as inputs to the various hydrologic reservoir units. This data pre-processing is necessary in order to use the linear unit hydrograph theory, as well as for maintaining a hydrologic budget between the surface and subsurface flow processes. Since infiltration determines the shape of the runoff hydrograph, it must be estimated as accurately as possible. When measured infiltration data is available, Horton’s exponential infiltration model is preferable due to its simplicity. However, estimating the parameters from Horton’s model constitutes a nonlinear least squares fitting problem. Hence, an iterative procedure that requires initialization is subject to convergence. In a similar context, the separation of direct runoff, interflow, and baseflow from the total hydrograph is typically done in an ad hoc manner. However, many practitioners use exponential models in a rather “layer peeling” fashion to perform this separation. In essence, this also constitutes an exponential data fitting problem. Likewise, certain variogram functions can be fitted using exponential data fitting techniques. In this paper we show that fitting a Hortonian model to experimental data, as well as performing hydrograph separation, and total hydrograph and variogram fitting can all be formulated as a system identification problem using Hankel-based realization algorithms. The main advantage is that the parameters can be estimated in a noniterative fashion, using robust numerical linear algebra techniques. As such, the system identification algorithms overcome the problem of convergence inherent in iterative techniques. In addition, the algorithms are robust to noise in the data since they optimally separate the signal and noise subspaces from the observed noisy data. The algorithms are tested with real data from field experiments performed in Surinam, as well as with real hydrograph data from a watershed in Louisiana. The system identification techniques presented herein can also be used with any other type of exponential data such as exponential decays from nuclear experiments, tracer studies, and compartmental analysis studies.     

长白山火山活动的现状和未来展望

长白山天池火山是中新世以来,特别是中更新世以来多次喷发并造成严重灾害的火山,是一座具有潜在喷发危险性的活动火山,文章主要阐述了全新世和近代火山活动及其喷发物,并对火山的现代活动与未来火山活动及其灾害作了评估。     

多道中心式记录强震仪的设计与应用

介绍了多道中心式记录强震仪的工作原理,性能及技术指标,给出了仪器的设计方法、理论分析和具体电气功能控制、时间服务系统等结构框图。文中还介绍了强震仪在地震现场观测获取的很有价值的地震记录。     

预应力混凝土连续梁桥振动特性变异及舒适度评价

由于预应力损失、混凝土收缩徐变、超载等原因,预应力混凝土桥梁出现了较强的振动。本文通过对福建省福州市闽江三桥全桥环境振动试验和正常运营条件下24小时的监测,研究预应力混凝土连续梁桥的动力特性及其变异和振动舒适度,结果表明:在较为稳定的风和温湿度环境下,固有频率在一天内的最大变化为3.06%,模态阻尼比的最大变化为37.93%,舒适度的狄克曼指标降到“能忍受短时间振动”的区域。     

2008年汶川地震近断层地震动的非平稳特征

利用中国强震动台网获得的汶川地震近断层强震动数据,研究汶川地震近断层地震动的强度和频率的非平稳特征,并对其非平稳特征的原因进行初步分析.研究表明近断层地震动强度和频率表现出很强的非平稳特性,这种非平稳特征主要受震源破裂机制、台站方位和局部场地条件的影响.破裂传播正向和反方向上地震动强度和频率的时间过程有显著的不同.在破...     

VOLUMETRIC SEDIMENT CONCENTRATION IN DEBRIS FLOWS

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中国地震局代表团赴欧洲进行紧急救援工作考察

为了尽快落实防震减灾三大工作体系之一－－“紧急救援”有关工作的开展,加速中国地震灾害紧急救援队的建设,中国地震局副局长岳明生率11人代表团于2001年8月访问了瑞士、荷兰、德国、法国等欧洲国家,对这些国家在紧急事务管理、灾害紧急救援组织与运作、救援装备的制造与配置及救援队培训等方面进行了较为细致的考察。     

Stochastic synthesis approximating any process dependence and distribution

An extension of the symmetric-moving-average (SMA) scheme is presented for stochastic synthesis of a stationary process for approximating any dependence structure and marginal distribution. The extended SMA model can exactly preserve an arbitrary second-order structure as well as the high order moments of a process, thus enabling a better approximation of any type of dependence (through the second-order statistics) and marginal distribution function (through statistical moments), respectively. Interestingly, by explicitly preserving the coefficient of kurtosis, it can also simulate certain aspects of intermittency, often characterizing the geophysical processes. Several applications with alternative hypothetical marginal distributions, as well as with real world processes, such as precipitation, wind speed and grid-turbulence, highlight the scheme’s wide range of applicability in stochastic generation and Monte-Carlo analysis. Particular emphasis is given on turbulence, in an attempt to simulate in a simple way several of its characteristics regarded as puzzles.