火灾对混凝土结构性能影响的研究

通过对比大量文献资料,分析了火灾高温对混凝土强度的影响,抗拉强度随温度的变化规律,以及不同的冷却方式对高温后混凝土强度的影响;分析了影响钢筋与混凝土高温粘结性能的因素及粘结性能随温度变化的趋势;总结了不同温度对不同类型钢筋抗拉强度的影响,并对今后的研究提出了一些建议.     

高温后高性能混凝土和细晶粒钢筋间粘结性能

配制了C100高性能混凝土,制作了标准立方体试块,并选用500 MPa级细晶粒钢筋制作了中心拔出粘结试件.分别对立方体试块和拔出试件进行了200,400,600,800 ℃的高温试验,完成了高温后的抗压强度试验和拔出粘结试验.基于试验结果,分析了高温作用对高性能混凝土抗压强度和粘结强度的影响,研究了高温后高性能混凝土抗压强度和粘结强度的关系,并通过与普通混凝土高温后粘结性能的对比,分析了高温后高性能混凝土和细晶粒钢筋间粘结性能的特点.     

自密实混凝土与老混凝土的粘结滑移关系研究

以自密实混凝土(SCC)为新混凝土材料,通过设计推出式剪切试验装置进行了新老混凝土粘结面的单剪试验,研究自密实混凝土与老混凝土的粘结滑移关系,并考察了新混凝土强度、粗糙度、界面剂以及粘结长度等主要因素的影响.试验结果表明,新老混凝土粘结滑移曲线的发展主要经历初始刚性阶段、弹性变形阶段、弹塑性变形阶段和塑性破坏阶段这四个部分.在实验结果的回归分析基础上,提出了自密实混凝土与老混凝土结合面粘结滑移本构关系的基本模式.     

高温下钢板与混凝土的粘结强度

型钢与混凝土的粘结是保证钢 混凝土组合结构构件正常工作的基础。本文通过高温状态下钢板与混凝土的力学性能,以及钢板与混凝土粘结性能的试验研究基础上,分析了在高温状态下,钢板与混凝土的粘结强度,比较了高温与常温下其粘结强度的大小,并给出了不同温度下钢板与混凝土的粘结强度的计算公式。为钢 混凝土组合结构构件的受力分析奠定了一定的基础。     

新老混凝土粘结的劈拉受力数值模拟及分析

采用Super91程序对双材料粘结试件和整体试件的劈拉受力进行数值模拟．从应力分析角度研究在劈拉荷载作用下，新老混凝土粘结的应力分布规律．研究结果表明新老混凝土粘结劈拉强度计算公式可近似采用整体混凝土劈拉强度计算公式．     

钢管混凝土界面粘结滑移性能

钢管混凝土界面粘结滑移性能的研究对于完善钢管混凝土设计理论和有限元分析模型具有重要意义。对钢管混凝土界面粘结滑移特点和研究现状进行了阐述,介绍了推出和推离两种试验研究方法以及国内外采用两种方法对钢管混凝土界面粘结强度的试验研究成果,总结比较了混凝土强度、钢管截面形状、钢管内表面状况及钢管混凝土构件受力状态对粘结强度的影响。针对钢管混凝土粘结滑移研究中存在的问题,着重分析了混凝土强度、收缩徐变、温度及构件受力状态等影响,并提出了钢管混凝土界面抗剪粘结力的组成、构件复杂受力状态下粘结性能、粘结滑移本构关系等需进一步研究的内容。     

高温对玄武岩纤维筋混杂纤维再生混凝土粘结性能的影响

通过中心拉拔试验研究玄武岩纤维筋(BFRP筋)与混杂纤维再生混凝土高温后粘结性能。选取体积掺量均为0.15%的玄武岩和纤维素纤维混掺再生混凝土中,目标温度为20°C、200°C、400°C、600°C和800°C。试验研究结果表明：相同温度条件下,混杂纤维的掺入有效提高了粘结强度；再生混凝土与BFRP筋的粘结弹性模量随着温度升高而逐渐降低；峰值粘结强度随温度升高出现先上升后降低的趋势；未掺入混杂纤维的随温度升高峰值粘结强度逐渐降低。建立了粘结-滑移曲线且与试验结果吻合较好,可为BFRP筋与混杂纤维再生混凝土粘结性能研究提供一定的参考。     

自密实混凝土与老混凝土粘结抗剪性能试验研究

对9组27个山形试件的自密实混凝土与老混凝土粘结面进行抗剪试验,考察刻槽密度、粘结面积、植筋对自密实混凝土与老混凝土粘结面抗剪强度的影响.试验结果表明,粘结面的不同处理方法对其抗剪强度影响较大,增大刻槽密度效果远好于增加新老混凝土的粘结面积,植入抗剪钢筋效果不如增大刻槽密度明显.通过试验分析,得出自密实新混凝土与老混凝土粘结抗剪强度计算式,为实际加固工程提供参考.     

环氧砂改善新老混凝土粘结强度试验研究

根据新老混凝土的粘结机理,提出采用环氧砂作为新老混凝土粘结的过渡层,通过劈裂试验方法,对不同粒径的砂和不同界面剂的新老混凝土粘结强度进行了试验研究.结果表明,环氧砂过渡层可明显改善新老混凝土之间的粘结劈拉强度,尤以米粒石的情况为好,同时,对环氧砂过渡层改善粘结性能的机理进行了探讨,并把该方法应用于某水利工程的修补加固中.实践表明,该方法具有良好的适用性和有效性.     

型钢-混凝土粘结机理的探讨

对型钢混凝土结构(SRC结构)中型钢-混凝土的粘结机理及影响粘结性能的主要因素进行了分析和探讨,并从混凝土保护层开裂与否的角度根据粘结力的扩散原理,提出了一种型钢-混凝土粘结强度的计算方法,可为型钢混凝土结构中型钢-混凝土粘结性能的研究及实际设计中粘结强度的计算提供参考.     

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.     

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.     

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).     

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.