APPLICATION OF MAP AND FILE INFORMATIONVISUALIZATION SYSTEM TO COMPREHENSIVEDIVISION OF NATURAL DISASTERS- Takingthe ChangjiangValleg as an Example     

HU Bao-qing    JIANG Mei-xin  JUN Su-lan  ZENG Qiao-song 《中国地理科学(英文版)》2001,(4)

In recent years，scholars at home and abroad have method，and that vanous disasters would be analyzed assynthetically studied natural dlsaste‘theoretically and an Integral．SHI Peilun（1991）putforwad a scientificmethodologlcally，as well as its cases analys。s（CND，term—regional disaster system，which Indicates that1987； MA et al，1990； MARBLE，1990； NE et al，the situation of a disaster（calamity loss）results from1999； PATAK et al，1982； SHI，1991；VAN et al，h…  相似文献   

Numerical prediction of blast‐induced stress wave from large‐scale underground explosion     

Chengqing Wu  Yong Lu  Hong Hao 《国际地质力学数值与分析法杂志》2004,28(1):93-109

This paper presents a numerical model for predicting the dynamic response of rock mass subjected to large‐scale underground explosion. The model is calibrated against data obtained from large‐scale field tests. The Hugoniot equation of state for rock mass is adopted to calculate the pressure as a function of mass density. A piecewise linear Drucker–Prager strength criterion including the strain rate effect is employed to model the rock mass behaviour subjected to blast loading. A double scalar damage model accounting for both the compression and tension damage is introduced to simulate the damage zone around the charge chamber caused by blast loading. The model is incorporated into Autodyn3D through its user subroutines. The numerical model is then used to predict the dynamic response of rock mass, in terms of the peak particle velocity (PPV) and peak particle acceleration (PPA) attenuation laws, the damage zone, the particle velocity time histories and their frequency contents for large‐scale underground explosion tests. The computed results are found in good agreement with the field measured data; hence, the proposed model is proven to be adequate for simulating the dynamic response of rock mass subjected to large‐scale underground explosion. Extended numerical analyses indicate that, apart from the charge loading density, the stress wave intensity is also affected, but to a lesser extent, by the charge weight and the charge chamber geometry for large‐scale underground explosions. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

Water transport from the North-east Irish Sea to western Scottish coastal waters: Further observations from time-trend matching of Sellafield radiocaesium     

W.A. McKay  M.S. Baxter 《Estuarine, Coastal and Shelf Science》1985,21(4):471-480

Radiocaesium isotopes, discharged into the North-east Irish Sea from the Sellafield (formerly Windscale) nuclear fuel reprocessing plant in Cumbria, have been employed as flow monitors to update and extend the record of coastal water movement from the Irish Sea to the Clyde Sea area and, further north, to Loch Etive. The temporal trends in radiocaesium levels have been used to determine the extent of water mixing en route and to define mean advection rates. Flow conditions from the Irish Sea have changed considerably since the mid-1970s, the residence time of northern Irish Sea waters being ～12 months during 1978–1980 inclusive. Average transport times of four and six months are estimated for the Sellafield to Clyde and Sellafield to Etive transects respectively. Sellafield ¹³⁷Cs levels in seawater were diluted by factors of 27 and 50 respectively during current movement to the Clyde and Etive areas. The decrease in salinity-corrected ¹³⁷Cs concentrations between the Clyde and Etive suggests that dilution by Atlantic water occurs, the latter mainly entering the Firth of Lorne from the west. The majority (～94%) of the radiocaesium supply to Loch Etive enters the Firth of Lorne via the portion of the coastal current circulating west of Islay, only ～6% arriving via the Sound of Jura.  相似文献   

A micromechanical finite element model for linear and damage‐coupled viscoelastic behaviour of asphalt mixture     

Qingli Dai  Martin H. Sadd  Zhanping You 《国际地质力学数值与分析法杂志》2006,30(11):1135-1158

This study presents a finite element (FE) micromechanical modelling approach for the simulation of linear and damage‐coupled viscoelastic behaviour of asphalt mixture. Asphalt mixture is a composite material of graded aggregates bound with mastic (asphalt and fine aggregates). The microstructural model of asphalt mixture incorporates an equivalent lattice network structure whereby intergranular load transfer is simulated through an effective asphalt mastic zone. The finite element model integrates the ABAQUS user material subroutine with continuum elements for the effective asphalt mastic and rigid body elements for each aggregate. A unified approach is proposed using Schapery non‐linear viscoelastic model for the rate‐independent and rate‐dependent damage behaviour. A finite element incremental algorithm with a recursive relationship for three‐dimensional (3D) linear and damage‐coupled viscoelastic behaviour is developed. This algorithm is used in a 3D user‐defined material model for the asphalt mastic to predict global linear and damage‐coupled viscoelastic behaviour of asphalt mixture. For linear viscoelastic study, the creep stiffnesses of mastic and asphalt mixture at different temperatures are measured in laboratory. A regression‐fitting method is employed to calibrate generalized Maxwell models with Prony series and generate master stiffness curves for mastic and asphalt mixture. A computational model is developed with image analysis of sectioned surface of a test specimen. The viscoelastic prediction of mixture creep stiffness with the calibrated mastic material parameters is compared with mixture master stiffness curve over a reduced time period. In regard to damage‐coupled viscoelastic behaviour, cyclic loading responses of linear and rate‐independent damage‐coupled viscoelastic materials are compared. Effects of particular microstructure parameters on the rate‐independent damage‐coupled viscoelastic behaviour are also investigated with finite element simulations of asphalt numerical samples. Further study describes loading rate effects on the asphalt viscoelastic properties and rate‐dependent damage behaviour. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

可移动中继节点在传感器网络中的节能应用     

唐帙  罗惠琼 《成都信息工程学院学报》2005,20(2):147-150

介绍了一种新颖的静态传感器网络实现方法，它利用可移动的中继节点来收集静态传感器网络的数据，有效的节约各传感器节点的能源，延长整个传感器网络的有效工作时间。也可以对该方法进行适当的改进，应用到某些实时性要求较高的场合中去。然后介绍了应用该原理实现的一个通讯协议。  相似文献   

On the practice of estimating fractal dimension   总被引：11，自引：0，他引：11  

James R. Carr  William B. Benzer 《Mathematical Geology》1991,23(7):945-958

Coastlines epitomize deterministic fractals and fractal (Hausdorff-Besicovitch) dimensions; a divider [compass] method can be used to calculate fractal dimensions for these features. Noise models are used to develop another notion of fractals, a stochastic one. Spectral and variogram methods are used to estimate fractal dimensions for stochastic fractals. When estimating fractal dimension, the objective of the analysis must be consistent with the method chosen for fractal dimension calculation. Spectal and variogram methods yield fractal dimensions which indicate the similarity of the feature under study to noise (e.g., Brownian noise). A divider measurement method yields a fractal dimension which is a measure of complexity of shape.  相似文献   

Morphological analysis of the drainage system in the Eastern Alps   总被引：2，自引：1，他引：1  

Jrg Robl  Stefan Hergarten  Kurt Stüwe 《Tectonophysics》2008,460(1-4):263-277

We study the morphology of the major rivers draining the Eastern Alps to test whether the active tectonics of this part of the orogen is reflected in the shape of channel profiles of the river network. In our approach we compare channel profiles measured from digital elevation models with numerically modelled channel profiles using a stream power approach. It is shown that regions of high stream power coincide largely with regions of highest topography and largest uplift rates, while the forelands and the Pannonian Basin are characterised by a significantly lower stream power. From stream power modelling we conclude that there is young uplift at the very east of the Eastern Alps, in the Bohemian Massif and in the Pohorje Range. The impact of the Pleistocene glaciations is explored by comparing properties of rivers that drain in proximal and distal positions relative to the ice sheet during the last glacial maximum. Our analysis shows that most knick points, wind gaps and other non-equilibrium features of catchments covered by ice during the last glaciations (Salzach, Enns) can be correlated with glacial processes. In contrast the ice free catchments of the Mur and Drava are characterized by channels in morphological equilibrium at the first approximation and are showing only weak evidence of the strong tectonic activity within these catchments. Finally, the channel profiles of the Adige and the divide between the upper Rhine and Danube catchments differ significantly from the other catchments. We relate this to the fact that the Adige and the Rhine respond to different base levels from the remainder of the Eastern Alps: The Adige may preserve a record from the Messininan base level change and the Rhine is subject to the base level lowering in the Rhine Graben.  相似文献   

汶川大地震（MS 8.0）同震变形作用及其与地质灾害的关系   总被引：12，自引：2，他引：10  

付小方  侯立玮  李海兵  王宗秀  邹付戈 《地质学报》2008,82(12):1733-1746

2008年5月12日发生于四川盆地西部龙门山断裂带的汶川大地震（MS 8.0）波及半个亚洲,震撼整个中国。本文通过地震后的实地调查,对发育在龙门山断裂带上的同震地表破裂带的分布、产状、继承性复活与变形特征,以及同震变形与地震地质灾害的关系等进行了初步总结,分析表明这次汶川大地震(MS 8.0)沿北川-映秀逆冲断裂和安县-灌县逆冲断裂同时发生地表破裂,前者产生以高角度逆冲兼右旋走滑为特征的地表破裂带长约275 km,后者产生以缓倾角逆冲作用为特征的地表破裂带长约80 km。汶川大地震的同震地表破裂带分布具有分段性特征,并与地表破坏程度的分带性有着一定的内在联系,详细研究表明,同震地表破裂带的产状直接影响地表破坏程度和地震地质灾害的强度,汶川大地震（MS 8.0）沿呈高角度陡倾的北川-映秀逆冲断裂发育的同震地表变形所产生的地表破坏程度和地震地质灾害的强度比沿缓倾角的安县-灌县逆冲断裂要强。从各种类型的地震断裂来看,具有垂直运动的逆冲型地震断裂所造成的地表破坏程度和地质灾害强度比具水平运动的走滑型地震断裂要强。因此,汶川大地震发生的破裂过程和同震地表变形与地震地质灾害的关系值得深入研究。  相似文献   

Water and power networks and urban fragmentation in Los Angeles: Rethinking assumed mechanisms     

Fionn MacKillop  Julie-Anne Boudreau 《Geoforum》2008,39(6):1833-1842

Los Angeles is often described as the epitome of urban fragmentation, a notion which in this context is frequently connected to, or even conflated with urban sprawl. At the same time, the city features integrated water and power networks which have been under public ownership for over 70 years. We thus have an apparent paradox in the context of the debate on ‘splintering urbanism’, between socio-spatial fragmentation and the integration of networks. In discussing the idea that deregulation of infrastructural networks exacerbates urban fragmentation, the authors use the case of Los Angeles in order to highlight the central role of private interests in management decisions concerning infrastructure networks. The authors carry out their analysis in an historical perspective, revealing that network integration and universal access can often serve private interests more than the public good. Urban fragmentation in Los Angeles, they conclude, is the result of a complex process of instrumentalisation of network development and management.  相似文献   

海拉尔盆地贝尔凹陷兴安岭群储层粘土矿物组成及成因研究   总被引：1，自引：0，他引：1  

刘钦甫  付正  候丽华  郑丽华 《矿物学报》2008,28(1):43-47

油田注水开发是保持地层能量,提高采收率的有效手段.海拉尔地区由于粘土矿物含量高,在开发过程中储层遇水易泥化、坍塌,严重影响油气的有效开采.通过X射线衍射、偏光显微镜观察和扫描电镜分析,确定了海拉尔盆地贝16断块兴安岭群储层自上而下存在三种粘土矿物组合:蒙脱石 高岭石 (绿泥石)→高岭石 伊/蒙间层 伊利石 (绿泥石)→伊利石 绿泥石 绿/蒙间层 伊/蒙间层.粘土总量在9.1%～69.1%之间,由地层浅部到深部呈现由高到低的变化规律.详细研究了水敏性极强的钠蒙脱石及其间层矿物,认为凝灰物质的水解蚀变以及长石和中、酸性岩屑在成岩过程中的次生变化是造成海拉尔地区粘土含量高的主要因素.  相似文献