中小型桥梁广域健康监测系统的研究

我国是桥梁大国,由于结构老化、运营管理以及建设质量等问题,近年来全国各地相继出现桥梁垮塌事故,造成了严重的人员伤亡和巨大的财产损失。为了保证既有桥梁的安全运营和尽可能延长其安全使用年限,对既有桥梁进行实时健康监测是非常必要的。由于桥梁健康监测系统投资、运营费用巨大和监测技术的不成熟,除少数特大型桥梁安装了监测系统9,9%以上的大、中、小跨径的桥梁都处于监测系统覆盖的盲区。文章主要探讨中小型桥梁健康监测系统的现状及近年来的进展,提出了一种基于智能传感器的中小型桥梁广域健康监测系统结构。     

浅谈桥梁结构健康监测

桥梁结构健康监测（对简称：桥监,下同）对于保障桥梁使用功能、安全运行、延长桥梁使用寿命、避免桥梁坍塌和局部破坏等严重事故发生有着重要的现实意义,近年来,桥梁结构健康监测成为国内外学术界、工程界的研究热点,本文阐述了桥梁结构健康监测的概念、监测系统、现状和发展方向。     

浅谈桥梁结构健康安全监测系统

本文基于桥梁结构健康安全监测的基本理论,分析了桥梁结构健康安全监测系统的实现方法和监测工作的基本要求,从而说明了桥梁结构健康安全监测系统能够为桥梁的维修、养护与管理决策提供依据和指导,具有重大的实用价值。     

大型桥梁健康监测概念与监测系统设计

大型桥梁健康监测力求对结构整体行为的实时监控和对结构状态的智能化评估.同时,对大跨度桥梁设计理论与力学模型的验证以及对结构和结构环境中未知或不确定性问题的调查与研究也正融入桥梁健康监测的内涵.据此首先简要地总结10多年来桥梁健康监测的研究状况,然后较系统地阐述桥梁结构健康监测的新概念,并从桥梁工程发展的角度探讨大型桥梁监测系统设计的有关问题,以期为监测系统的开发提供借鉴大型桥梁健康监测概念与监测系统设计@张启伟     

大型桥梁健康监测动态及发展趋势

大型桥梁健康监测是近年来国际上的研究热点。首先给出了桥梁结构健康监测系统的内涵和基本组成 ,再结合国内外已建立健康监测系统的几座典型桥梁 ,阐述了健康监测系统的内容和设计准则。回顾和总结了桥梁健康监测近年来所取得的成就 ,并分析了存在的问题和难点。最后展望了桥梁健康监测的发展趋势 ,重点探讨了桥梁健康监测的智能控制技术。     

润扬长江大桥结构健康监测系统研究

介绍了国家重点工程——润扬长江大桥结构健康监测系统研究的主要成果，综合评述了大跨桥梁健康监测研究的主要进展和关键问题．主要内容包括：系统的构成、目标和主要子系统的功能、监测项目的确定和布点策略、监测仪器的选择与检测技术分析、桥梁结构状态识别与安全性评估的方法与策略等．文中较为系统地论述了目前大跨桥梁健康监测系统建立与研究中的主要问题，指出了结构健康监测技术、状态识别和可靠性评估的可能技术途径，阐述了大跨桥梁健康监测系统的发展方向．     

大型桥梁健康监测概念与监测系统设计

大型桥梁健康监测力求对结构整体行为的实时监控和对结构状态的智能化评估,同时,对大跨度桥梁设计理论与力学模型的验证以及对结构和结构环境中未知和不确定性问题的调查与研究也正融入桥梁健康监测的内涵,据此首先简要地总结10多年来桥梁健康监测的研究状况,然后较系统地阐述桥梁结构健康监测的新概念,并从桥梁工程发展的角度探讨大型桥梁监测系统设计的有关问题,以期为监测系统的开发提供借鉴。     

谈大跨度桥梁结构的健康监测

本文阐述了大跨度桥梁结构健康监测的必要性,介绍了国内外桥梁结构健康监测技术的研究与应用现状,指出了健康监测的概念系统的组成以及主要监测内容,分析了桥梁结构健康监测技术的不足和发展趋势。     

北斗和GPS系统在病害影响下桥梁健康监测中的应用

高原山区桥梁数量比例相对较高,但是,各种原因导致桥梁出现缺陷和病害,加之地形复杂、通信落后,无法实时、有效地监控各桥梁的健康状态.因此,急需通过先进技术进行监测和预警,提前进行预防性养护,保障人民生命财产安全.鉴于此,本文分析和梳理了影响桥梁健康的病害及其形成原因,这对桥梁监测和维护具有一定的参考意义.除此之外,本文分析并设计了基于低功耗的北斗/GPS桥梁健康监测系统,该系统利用卫星监测手段的优势,有效地解决高原山区有线通信网络覆盖不够、专业技术人员缺乏的问题,真正实现对高原山区现役桥梁的动态监测及安全评价.目前,该系统已在云南省进行实施和应用,不仅成本低、效率高,而且能够实现实时动态监测,非常适合在高原山区进行推广和应用.     

润扬大桥结构健康监测策略

对建立大跨桥梁结构健康监测系统的关键问题--大跨桥梁结构健康监测策略进行了分析研究,阐述了大跨桥梁结构健康监测项目的选择依据、传感器优化布设的原则与主要依据、传感器选择的原则等.提出了综合考虑大桥的结构特点和各个方面对系统功能的要求,通过费用-效益比分析,确定长期监测和周期检测内容的项目选择原则.关于传感器的布设,提出了遵循从状态评估的需要出发,以有效和经济为目标,使测点能够发挥最大效应的原则,综合结构安全评估、传感器布设优化理论等因素进行优化布设的方法.在有限元分析的基础上,应用遗传算法进行了润扬大桥结构健康监测系统振动和应变传感器优化布置的理论分析.然后进行了润扬大桥结构健康监测传感器系统的总体设计.     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

Perspherical Approaches for Electrons in Atoms and Charged Excitons in Quantum Wells

Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to     

Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Scale-based spatial data model for GIS

Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to