带约束拉杆方形钢管混凝土短柱延性计算

采用带约束拉杆方形钢管混凝土的本构关系,建立了基于纤维模型法的模拟带约束拉杆方形钢管混凝土短柱承载力-变形全过程曲线的非线性分析方法,计算结果与试验结果吻合良好.利用经试验验证的计算程序对带约束拉杆方形钢管混凝土短柱的单向和双向偏压延性进行较系统的参数分析,回归了带约束拉杆方形钢管混凝土单向和双向偏压延性简化计算公式,公式的计算精度高,形式简单.     

带约束拉杆方形钢管混凝土偏压短柱的试验研究

为了解带约束拉杆方形钢管混凝土短柱在单向偏心荷载作用下的力学性能，进行了14个试件的偏压试验，主要研究截面含钢率、荷载偏心率以及约束拉杆设置对带约束拉杆方形钢管混凝土短柱偏压力学性能的影响．结果表明，方形钢管混凝土短柱试件的承载力随着偏心率的增大而减小，随着钢管壁厚度（含钢率）的增大而增大，设置约束拉杆有助于该试件极限承载力和延性的提高．文中还利用国内现有规程中的方法对该类试件的承载力进行了计算，发现规程计算结果总体上低估了带约束拉杆方形钢管混凝土偏压试件的级限承载力，     

带约束拉杆方形钢管混凝土柱偏压承载力特性

采用带约束拉杆方形钢管混凝土的本构关系,利用基于纤维模型法的非线性分析程序对带约束拉杆方形钢管混凝土短柱承载力进行数值计算,计算结果与试验结果吻合良好。对带约束拉杆方形钢管混凝土偏压短柱进行参数分析的结果表明,随着约束拉杆间距的减少、直径的增大,偏压短柱的极限承载力增大;随着钢管壁厚的增大,偏压短柱的N/Nu-M/Mu曲线往内收拢;随着混凝土强度和钢材强度的提高,偏压短柱的N/Nu-M/Mu曲线向外凸出;双向偏压短柱的极限承载力在最大主惯性轴方向达到最大,在最小主惯性轴方向达到最小;各参数对单向偏压和双向偏压短柱的N/Nu-M/Mu曲线的影响相类似。     

带约束拉杆矩形钢管混凝土短柱延性计算

采用带约束拉杆矩形钢管混凝土的本构关系,建立了基于纤维模型法的模拟带约束拉杆矩形钢管混凝土短柱承载力-变形全过程曲线的非线性分析方法,计算结果与试验结果吻合良好。对带约束拉杆矩形钢管混凝土偏压短柱进行参数分析,回归了带约束拉杆矩形钢管混凝土短柱单向和双向偏压曲率延性系数的简化计算公式,公式的计算精度高,形式简单。     

带约束拉杆矩形钢管混凝土柱的偏压性能

进行了7 个带约束拉杆和2个不设约束拉杆矩形钢管混凝土短柱的单向偏心受压试验,主要研究偏心率、约束拉杆水平间距对矩形钢管混凝土短柱偏压性能的影响。试验研究结果表明,约束拉杆的设置有助于提高矩形钢管混凝土偏压短柱的延性,延迟钢管的局部屈曲。带约束拉杆矩形钢管混凝土柱的偏压承载力随偏心率的增大而减小。在相同偏心率下,试件延性随拉杆水平间距减小而增大。采用带约束拉杆矩形钢管混凝土的本构关系,利用条带法对试件承载力进行数值计算,计算结果与试验结果吻合良好。同时,利用国内现有规程GJB4142-2000、DBJ13-51-2003以及CECS159:2004对试件承载力进行计算,规程计算结果总体上低估了带约束拉杆矩形钢管混凝土偏压试件的承载力。     

带约束拉杆L形钢管混凝土短柱的偏压试验研究

对8个带约束拉杆L形钢管混凝土偏压短柱试件进行了试验研究,讨论其在不同约束拉杆设置、偏心率以及荷载角下的偏压性能.结果表明,约束拉杆的设置改变了钢管的屈曲模态,延迟了局部屈曲的发生,有助于L形钢管混凝土偏压短柱的承载力和延性的提高.在加载后期,处于加载肢的拉杆比处于非加载肢的拉杆对核心混凝土的约束作用明显,其中双列拉杆试件的肢端拉杆比肢内拉杆的约束作用更大.临近或达到极限承载力后,近力侧钢管壁对核心混凝土的约束作用较明显.利用纤维模型法计算的试件偏压极限承载力结果与试验结果吻合良好.     

带约束拉杆L形钢管混凝土短柱轴压性能的试验研究

进行了6个带约束拉杆和1个不设约束拉杆L形钢管混凝土短柱的轴心受压试验,分析了钢管壁厚度、约束拉杆直径和间距等主要参数对带约束拉杆L形钢管混凝土短柱轴压性能的影响.试验研究表明,在轴心压力作用下,设置了的L形钢管混凝土短柱的极限承载力有所提高,拉杆的设置能改善核心混凝土的约束作用,延迟或避免钢管在应力达到屈服强度前发生局部屈曲而导致构件的过早破坏,从而使L形钢管混凝土轴压短柱的延性有较大幅度的提高.     

方形钢管约束下核心凝土的本构关系

分析了方形钢管混凝土在轴压下的受力机理,将钢管对混凝土的约束作用等效为有效侧向应力,借鉴典型的约束混凝土本构模型,提出了方形钢管约束下核心混凝土的等效单轴受压本构关系.基于试验结果,讨论确定了所提出的本构关系的几个关键参数和强度指标,即峰值应变修正系数、钢管有效侧向压应力系数、峰值时钢管的横向应力等.采用建议的本构关系计算了轴压下方形钢管混凝土短柱的荷载-应变全过程曲线,计算结果与试验结果吻合良好.所建议的本构关系可用于评估方形钢管混凝土短柱的极限承载力和延性.     

基于统一理论的带拉杆方、矩形CFT轴压承载力

在钢管混凝土统一理论基础上,结合配置约束拉杆的方形和矩形钢管混凝土短柱轴压试验结果,通过研究带拉杆方形钢管混凝土的拉杆约束系数与轴压承载力之间的关系,修正统一理论轴压承载力公式,得出带拉杆方形钢管混凝土轴压承载力计算公式.对于带单向拉杆矩形钢管混凝土,提出将矩形截面以拉杆为界线划分为几个子区域,并将拉杆视为等效钢板,采用统一理论计算公式计算每个子区域的轴压承载力,叠加后得出带拉杆矩形钢管混凝土轴压承载力计算公式.以上两个修正公式均考虑了拉杆的影响,拓宽了统一理论计算公式的适用性,分别用其计算的带拉杆的方形和矩形钢管混凝土轴压承载力与试验结果吻合良好.     

带约束拉杆十形钢管混凝土短柱承载力统一解

基于统一强度理论,以带约束拉杆十形钢管混凝土短柱为研究对象,将十形截面划分为1个无拉杆和4个有拉杆的矩形区域,考虑中间主应力、材料SD效应及钢管宽厚比的影响,同时考虑混凝土所受的侧向约束应力,分析其受力机理及约束模型,建立了该柱的轴压承载力计算公式,并在此基础上考虑长细比和偏心率的影响,得到了偏心受压承载力计算公式。所得理论结果与试验结果吻合良好,验证了公式的正确性。同时研究了各类参数对承载力的影响规律,结果表明:承载力随拉杆间距和钢管宽厚比的增大而减小;拉杆横向间距越大,纵向间距对承载力影响越小;拉杆直径对承载力的影响不明显;偏压承载力随偏心率的增大明显降低。     

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