玄武岩纤维机场道面混凝土抗冻性试验研究

针对当前机场道面混凝土遭受冻融循环破坏而出现的耐久性问题,试验采用纤维增强混凝土技术。将两种规格的玄武岩纤维按0.1%的体积掺量掺入机场道面混凝土,进行了冻融循环试验;以及冻融前后动弹模量,质量损失和混凝土表面状态的对比分析。结果表明:掺玄武岩纤维的机场道面混凝土可明显提高抗冻性,抗冻等级提高了2.7~3.3倍。长度20 mm直径20μm体积掺量0.10%的玄武岩纤维道面混凝土抗冻性能最佳。     

混杂纤维超高强混凝土抗裂性能试验研究

采用改进的平板法进行聚丙烯、玄武岩纤维掺量对超高强混凝土抗裂性能影响的试验研究,并将掺量为6 kg·m-3的玄武岩纤维和体积掺量为1%的钢纤维分别与不同掺量的聚丙烯纤维进行混杂,研究混杂纤维超高强混凝土的抗裂性能.试验结果表明,纤维掺入超高强混凝土中能改善超高强混凝土的早龄期抗裂性能,并且混杂纤维混凝土的抗裂性能要明显优于单掺一种纤维的混凝土,体现出正混杂效应.     

混杂纤维超高强混凝土抗裂性能试验研究

采用改进的平板法进行聚丙烯、 玄武岩纤维掺量对超高强混凝土抗裂性能影响的试验研究,并将掺量为6 kg·m^-3的玄武岩纤维和体积掺量为1％的钢纤维分别与不同掺量的聚丙烯纤维进行混杂,研究混杂纤维超高强混凝土的抗裂性能. 试验结果表明,纤维掺入超高强混凝土中能改善超高强混凝土的早龄期抗裂性能,并且混杂纤维混凝土的抗裂性能要明显优于单掺一种纤维的混凝土,体现出正混杂效应.     

纤维自密实混凝土力学性能及早期抗裂性能研究

对掺聚丙烯腈纤维、钢纤维和混杂纤维自密实混凝土的配制进行了系列试验,得到纤维自密实混凝土的配制方法及纤维的适宜掺量。试验结果表明,当聚丙烯腈纤维掺量不高于1.2 kg/m3、钢纤维体积掺量不高于1.5%的情况下,通过适当调整外加剂的掺量、类型以及砂率,可以使混凝土达到自密实的工作性能。纤维自密实混凝土的28 d立方体抗压强度、劈拉强度试验表明,聚丙烯腈纤维掺量对自密实混凝土抗压强度的影响较小,劈拉强度随掺量增大而提高,但当掺量达到1.2 kg/m3时,将导致其劈拉强度的降低,因此聚丙烯腈纤维的掺量宜控制在0.9 kg/m3时为佳;钢纤维体积率变化对自密实混凝土劈拉强度的增强效果明显,混杂纤维的掺入对自密实混凝土抗压强度的影响较小,但对劈拉强度有一定影响,即掺量越大,劈拉强度越高。纤维自密实混凝土早期抗裂性能试验结果表明,在自密实混凝土中掺入纤维,将有助于早期抗裂性能的提高。     

混杂纤维对活性粉末高温后力学性能的影响

研究了聚丙烯纤维体积掺量为0.3%时,不同钢纤维掺量对活性粉末混凝土高温后轴心抗拉强度、抗压强度、抗折强度、拉压比、折压比的影响及其随温度的变化规律。结果表明：聚丙烯纤维能够有效抑制爆裂、改善活性粉末高温后的性能;混掺聚丙烯纤维和钢纤维能够提高高温后混杂纤维活性粉末混凝土力学性能,500℃之前损伤率较小,500℃之后损伤率较大;混掺2%钢纤维的混杂纤维活性粉末混凝土高温后的拉压比、折压比提高较多,混杂纤维可以优势互补。     

混杂纤维对活性粉末混凝土高温后力学性能的影响

研究了聚丙烯纤维体积掺量为0.3%时,不同钢纤维掺量对活性粉末混凝土高温后轴心抗拉强度、抗压强度、抗折强度、拉压比、折压比的影响及其随温度的变化规律。结果表明:聚丙烯纤维能够有效抑制爆裂、改善活性粉末高温后的性能;混掺聚丙烯纤维和钢纤维能够提高高温后混杂纤维活性粉末混凝土力学性能,500℃之前损伤率较小,500℃之后损伤率较大;混掺2%钢纤维的混杂纤维活性粉末混凝土高温后的拉压比、折压比提高较多,混杂纤维可以优势互补。     

混杂纤维增强高性能混凝土弯曲韧性研究

选用钢纤维、塑钢纤维和杜拉纤维,在总体积掺率不超过1％条件下,进行了二元或三元混杂纤维增强高性能混凝土的抗压试验、劈拉试验以及带切口梁三点弯曲试验.绘制了荷载-挠度曲线以及荷载-裂缝开口位移曲线(CMOD),计算得到了混凝土开裂各阶段纤维所贡献的能量吸收值以及等效弯拉强度,对比分析了纤维混杂方式、掺量对混凝土基本力学性能以及峰值荷载后变形性能的影响.研究结果表明:三元混杂纤维混凝土具有较基体混凝土、单掺或二元混杂纤维增强混凝土更优的力学性能和变形性能,弯拉强度最大提高了28％,弯曲韧性试验荷载-位移曲线均呈现出明显的应变硬化现象,并表现出优越的裂缝控制能力;当纤维三元混杂且水灰比为0.31时,由0.7％弓形钢纤维、0.19％塑钢纤维与0.11％杜拉纤维混杂制得混凝土样本的强度以及弯曲韧性最优.     

混杂纤维自密实混凝土的性能试验与分析

为了研究混杂纤维对自密实混凝土(SCC)工作性能及力学性能的影响,进行了4种纤维体积掺量(0%,0.05%,0.1%和0.15%)的纤维自密实混凝土(玄武岩纤维、聚丙烯纤维以及玄武岩-聚丙烯混杂纤维)的塌落度扩展度试验、J型环试验和28d抗压强度、劈裂抗拉强度和抗折强度试验,并通过SEM图像分析纤维自密实混凝土的微观形貌。结果表明：纤维掺量的增加导致自密实混凝土流动性能下降,但仍满足自密实混凝土工作性能的要求;混杂纤维的掺量在一定范围内,对自密实混凝土的抗压强度、劈裂抗拉强度和抗折强度均有不同程度的提高作用。可见获得纤维的合理掺量十分重要。     

玄武岩纤维-微硅粉混凝土力学性能研究

为了提高高强混凝土的阻裂性能及韧性,以C60高强混凝土为研究对象,混掺玄武岩纤维和微硅粉矿物掺合料,通过正交试验方法,研究了玄武岩纤维和微硅粉对高强混凝土力学性能以及抗裂性能的影响。在混凝土基本力学性能试验中得到掺合料的最佳掺量基础上,通过圆环抗裂试验研究了两种掺合料对混凝土抗裂性能的影响效果。结果表明:当玄武岩纤维掺量为3kg/m~3、微硅粉掺量为7%时,混凝土的基本力学性能达到最佳值;玄武岩纤维-微硅粉混凝土相对微硅粉混凝土的裂缝降低系数为56.3%。由此得出结论:玄武岩纤维-微硅粉混凝土能够增强高强混凝土的基本力学性能和抗裂性能。     

纤维自密实混凝土性能试验研究

为了研究不同掺量的钢纤维与聚丙烯纤维对自密实混凝土工作性能和强度的影响,对掺入聚丙烯纤维、钢纤维以及两种纤维混杂的自密实混凝土进行工作性能、抗压强度、抗拉强度试验和混杂效应分析。试验结果表明:工作性能随着纤维掺量的增加而降低,且钢纤维对工作性能的影响更加明显;钢纤维对混凝土抗压强度、抗拉强度的提高大于聚丙烯纤维;两种纤维混杂时更能有效改善自密实混凝土脆性破坏特征,当钢纤维掺量为0.6%,聚丙烯纤维掺量为0.2%时,抗压强度的增幅最大,当钢纤维掺量为0.6%,聚丙烯掺量为0.15%时,抗拉强度的增幅最大;抗压强度与劈裂抗拉强度均部分呈现正混杂效应,且劈裂抗拉强度存在最优混杂效应。     

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