小壁厚组合截面冷弯薄壁型钢构件承载力研究

根据美国钢铁协会（AISI）的试验资料对背靠背双拼冷弯薄壁卷边槽型截面横梁的承载力试验进行了介绍．并将试件的试验承载力与GB50018-2002冷弯薄壁型钢结构技术规范中规定的计算结果作了比较。对比结果表明,按照GB50018-2002规定计算厚度小于2mm冷弯薄壁型钢受弯构件承载力是可行的。     

现行规范对高强复杂加劲冷弯构件力学性能适用性研究

目的研究《冷弯薄壁型钢结构技术规范》(GB50018-2002)对G550级高强复杂加劲冷弯薄壁钢材的适用性,提出计算其承载力的修正系数.方法对17根壁厚均为1.1 mm的G550高强钢材进行试验和理论计算,分析高强新型冷弯箱型组合截面受弯构件力学性能.结果无论试验受弯极限承载力或是理论受弯极限承载力,DS1型截面构件均比DS2型截面构件提高近20%;试件的合理高宽比为2~4;对于DS1型截面构件建议不折减,对于DS2型截面构件建议采用0.8的折减系数.结论现行《冷弯薄壁型钢结构技术规范》(GB50018-2002)对G550级高强复杂加劲构件基本适用,对于新型高强冷弯薄壁型钢梁的受弯极限承载力一般情况下要大于规范给出的理论受弯极限承载力.不同的截面构件所适合的折减系数不同,工程设计可根据构件截面的情况决定是否折减.     

小壁厚组合截面冷弯薄壁型钢构件承裁力研究

根据美国钢铁协会(AISI)的试验资料对背靠背双拼冷弯薄壁卷边槽型截面横梁的承载力试验进行了介绍,并将试件的试验承载力与GB 50018—2002冷弯薄壁型钢结构技术规范中规定的计算结果作了比较。对比结果表明,按照GB 50018—2002规定计算厚度小于2 mm冷弯薄壁型钢受弯构件承载力是可行的。     

冷弯薄壁卷边槽钢轴压柱有效宽度法和直接强度法计算对比

对冷弯薄壁卷边槽钢轴压柱承载力分别用中国规范(GB50018-2002)中的有效宽度法和美国规范AISI S100-2007附录中的直接强度法(DSM)进行了稳定承载力计算。计算结果表明:采用0.85f y的直接强度法可以有效预测冷弯薄壁卷边槽钢轴压柱稳定承载力,与GB50018-2002中的有效宽度法计算结果吻合较好,可供修订规范和设计时参考。     

冷弯薄壁槽钢轴压柱承载力的计算方法探讨

对冷弯薄壁槽钢轴压柱分别用中国规范(GB50018-2002)中的有效宽度法(EWM)和美国规范(AISI S100-2007)中的直接强度法(DSM)进行了稳定承载力计算,并与试验进行了比较.结果表明:有效宽度法和直接强度法均可有效预测冷弯薄壁槽钢轴压柱稳定承载力,GB50018-2002中的有效宽度法计算结果偏于安全.     

冷弯薄壁型钢卷边槽形截面构件非线性畸变屈曲承载力计算方法

为研究冷弯薄壁型钢卷边槽形截面构件畸变屈曲承载力计算方法,基于能量法采用大挠度理论对部分加劲板件的非线性畸变屈曲承载力进行推导分析,得到冷弯薄壁型钢部分加劲板件屈曲稳定系数和畸变屈曲承载力计算方法,并采用有限元分析结果验证该方法的精确性。利用我国现行国家标准GB 50018—2002"冷弯薄壁型钢结构技术规范"中的有效宽度法公式计算畸变屈曲承载力,与分析提出的建议方法计算结果进行对比分析。研究结果表明:基于能量法提出的计算畸变屈曲承载力方法是精确、可行的。在修正部分加劲板件屈曲稳定系数的基础上,可以采用我国现行国家标准GB 50018—2002"冷弯薄壁型钢结构技术规范"中有效宽度法的公式计算发生畸变屈曲的构件截面承载力,从而建立了考虑局部和畸变屈曲承载力的统一计算公式。     

冷弯薄壁型钢拼合箱形截面短柱承载力叠加法

基于中国规范GB 50018—2002中的有效宽度法和北美规范中的有效宽度法及直接强度法,利用已有的试验数据和文章中有限元参数分析结果,计算了66根通过ST4.8自攻螺钉将单肢C形及单肢U形截面构件连接而成的冷弯薄壁型钢（CFS）拼合箱形截面短柱局部屈曲的承载力. 理论值与试验和有限元值比较分析表明：中国规范GB 50018—2002和北美规范有效宽度法计算结果偏于保守,而北美规范直接强度法可以准确预测构件的承载力,但会存在不安全现象. 基于以上结果,给出了关于冷弯薄壁型钢拼合箱形截面短柱局部屈曲承载力的计算方法——叠加法,并提出了关于CFS拼合箱形截面轴压短柱的理论计算公式. 然后依据48根有限元试件的变参数结果,回归分析得出理论计算公式的组合系数α,得到计算拼合柱极限承载力的公式. 最后通过与试验数据及中美规范计算结果对比,验证了承载力叠加法的适用性与准确性,也为CFS拼合箱形截面短柱承载力的计算提供了简易的方法.     

冷弯厚壁型钢螺栓连接抗剪性能试验

通过30个厚度为10 mm的冷弯厚壁型钢螺栓连接件的静力拉伸试验，考察不同边距、端距下试件的破坏模式、抗剪承载力及相关规范的适用性，并基于试验结果对规程建议公式进行修正.研究结果表明：在考察的边距、端距范围内，试件出现净截面、剪出、剪出与孔壁承压混合三种破坏模式；当试件发生剪出和剪出与孔壁承压混合破坏时，剪切破坏面上存在裂缝；试件达到极限承载力之前，出现在螺栓孔前的裂缝会减小钢板的受剪面积，导致试件抗剪承载力的计算结果高于实测结果；基于实际受剪面修正的剪出破坏承载力计算公式概念清晰，计算精度高；修正后美国规范AISC 360-16的计算结果与试验结果吻合最好，未修正的美国规范ANSI/AISC 360-16次之，而欧洲规范EN 1993-1-8的计算结果偏保守，中国规范GB 50018-2002的计算结果过于保守.     

冷弯薄壁型钢自攻螺钉连接抗剪性能试验研究

介绍单颗自攻螺钉连接件和多颗自攻螺钉连接件的试件制作、加载装置及它们抗剪承载力的试验全过程.根据试验过程和破坏现象,总结不同试件的荷载-变形曲线、抗剪承载力试验值及破坏模式.依据各国规范及相关文献,结合试验数据,验证中国规范GB 50018-2002及美国AISI规范对于计算单颗螺钉抗剪承载力的可行性及可靠性.通过探讨不同母材厚度、不同螺钉数目、不同螺钉排列方式及不同螺钉间距对自攻螺钉连接抗剪承载力的影响,总结得到自攻螺钉连接抗剪试验破坏的几个阶段、主要破坏模式和影响因素:(1)螺钉数目及间距是影响自攻螺钉连接抗剪性能的最主要因素;(2)螺钉排列方式对连接的抗剪性能影响较小;(3)在某些破坏模式下,母材厚度也是影响连接件抗剪性能的主要因素之一.通过对试验数据统计分析,发现自攻螺钉群的抗剪承载力具有“群体折减效应”,并给出能反映“群体折减效应”的螺钉群效率系数的分布范围,发现螺钉间距及数目也是影响效率系数的主要因素.     

冷弯型钢卷边槽形截面轴压构件部分加劲板件屈曲系数研究

采用有限条程序CUFSM计算不同截面尺寸的冷弯卷边槽形截面轴压构件弹性屈曲应力,通过回归分析得到部分加劲板件的屈曲稳定系数建议计算公式,同时采用澳洲规范（AS／NZS4600：2005）、北美规范（AISIS100-2007）、欧洲规范（EN1993—1—3：2006）、美国规范（ANSI／AISICFSSPEC-1996）、中国规范（GB50018—2002）中的有效宽度法以及建议的加劲板件屈曲系数对收集到的国内外共100根卷边槽形截面轴压构件极限承载力进行计算分析．结果表明：我国现行规范《冷弯薄壁型铜结构技术规范》（GB50018—2002）和欧洲规范（EN1993—1-3：2006）计算结果偏于保守,而澳洲规范（AS／NZS4600--2005）、北美规范（AISIS100-2。07）和美国规范（ANSI／AISICFSSPEC--1996）计算结果偏不安全．利用建议公式再根据我国现行规范《冷弯薄壁型钢结构技术规范》（GB50018—2002）计算所得结果与实验值吻合较好,可供设计和修订规范参考．     

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…     

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。     

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     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

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.     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.