Microscopic fatigue processes in a plain-weave glass-fibre composite

This paper focuses on the microscopic damage and progressive failure of a composite reinforced by plain-weave glass cloth under tensile fatigue loading. The fatigue process was divided into three stages like that of multi-directional laminates. It was found that the internal damage at each stage (matrix cracks, debonds in the weft, successive debonds in the warp and ‘metadelaminations’ between warps and wefts) occurred near the cross-over point of the fabric. The modulus decay mechanism was explained by considering the progression of this internal damage. From the end of the first stage to the beginning of the middle stage, a characteristic damage state (CDS) (called a ‘meta-CDS’) was observed. It was found that woven composites have a unit area of damage accumulation (called a ‘unit cell’) and the damage of each unit cell and its distribution control the total fatigue damage of the material.     

热采水平井整体开发草13块砂砾岩薄层特稠油

热采水平井技术是科学有效开发稠油油藏的重要手段。以胜利油田草13块为例，系统论述了利用热采水平井整体开发具有边底水的砂砾岩薄层特稠油油藏的开发程序和研究方法。在油蒇精细描述的基础上，通过热采筛选、产能评价、直井和水平井数值模拟、开发方式优化及指标预测等油藏工程研究技术方法，综合论证了利用热采水平井整体开发草13块的必要性和可行性，总结了砂砾岩薄层特稠油油藏水平井油藏工程设计中应遵循的原则，并在生产实践中见到明显效果，为胜利油田其它区块和类似油田的开发提供了借鉴和指导。     

杜84断块超稠油开发中后期稳产对策研究

对杜84断块超稠油生产中后期暴露的主要矛盾，即随着轮次升高，周期吞吐效果变差，井下技术状况日益变差。油层动用不均，汽窜加剧等问题进行了分析。并提出了相应的稳产对策-实施多井整体吞吐，大修复产，调剖等措施。现场应用证明，这些措施基本能够确保杜84断块超稠油中后期的稳产。     

凝析气藏物质平衡方程的改进与应用

为了提高凝析气藏油气采收率，通常采用目前最有效的循环注气保持地层压力的开采方式。在此开采方式下，直接采用气藏物质平衡方程进行地质储量计算将出现很大偏差。针对这种情况，将气藏物质平衡方程进行了改进，得到凝析气藏在注气开发方式下的物质平衡方程。     

Electrochemistry of polyaniline: Study of the pH effect and electrochromism

Polyaniline was electrochemically synthesized from an aqueous medium with various acid electrolytes via potentiodynamic and potentiostatic techniques. The electrochemical synthesis of polyaniline was studied over various substrates, including Pt, Ti, Ni, and SnO₂ coated glass, and in various acid electrolytes. Cyclic voltammograms of electrochemically synthesized polyaniline were studied in HCl in a pH range of 1–4. Probable electrochemistry and chemical changes were deduced that occurred when polyaniline film was electrochemically oxidized and reduced between ?0.2 and 1.0 V versus a Ag/AgCl reference electrode in an acidic electrolyte at pH 1, and three corresponding oxidation and reduction peaks were described instead of two redox peaks (as observed by W. S. Huang, B. D. Humphrey, and A. G. MacDiarmid, J Chem Soc Faraday Trans 1 1986, 82, 2385). The electrochromic property was studied with changes in the chemical states of polyaniline during electrochemical oxidation and reduction. A new viscous electrolyte, aqueous AlCl₃ (pH 2), saturated with AgCl was used for the construction of an electrochromic display device. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 378–385, 2002     

Micromechanical characterisation of fibre/matrix interfaces

Theoretical analyses for the single fibre pull-out and push-out models under monotonic loading are given which are based on a shear-lag analysis in a fracture mechanics approach considering non-constant friction at the debonded interface as a result of fibre Poisson contraction (or expansion). The solutions allow the determination of typical fibre/matrix interfacial properties such as the interfacial fracture toughness, G_ic, the coefficient of friction, μ, and the residual clamping stress, q₀. Under cyclic loading the interfacial properties are expected to degrade as a result of repetitive abrasion, and a power law function is assumed between μ and the number of elapsed cycles, N. However, G_ic is assumed to be unaffected and a fracture mechanics based debond criterion is derived for the relationship between the external applied stress, the debond length and the reduced friction coefficient for both fibre pull-out and fibre push-out. In addition, the relative displacements between the free fibre end and the matrix top are obtained for cyclic fatigue when the fibre is loaded and unloaded. A relationship obtained for the protrusion (or intrusion) length in fibre pull-out (or push-out) experiments allows the severity of the interface frictional degradation to be evaluated and characterised. Similarities and differences in the frictional degradation behaviour between fibre pull-out and push-out are also identified.     

低渗透油藏超短周期间歇注水方式研究

大港油田南区低渗透油藏两相共渗区窄，注水开发短期内含水上升迅速，根据间歇注水理论，并借鉴国内外油田的实验经验，1998年在舍女寺油田女20、女34区块开展超短周期（周期0．5－5d)间歇注水试验。总结不同注水周期和频率及油并不同含水级别对其效果的影响。认为超短周期间歇注水可改善油层动用状况，对中、低含水受益油井之注水井有较好的适用性，为低渗透油藏注水开发提出了一种经济有效的方法。图1参（王学立摘）。     

多周期CO2吞吐研究与应用

通过数值模拟和室内、现场试验，对多周期CO2吞吐进行了系统研究，在实践的基础上，得出了在低渗透油田进行多周期CO2单井吞吐是可行的，并且具有较好的经济效益的结论，两口井7个周期表明，单井最大吞吐周期可达4次，试验结果对多种类型油藏提高采收率具有较大的经济意义。     

循环荷载作用下饱和黏性土的弹塑性双面模型

基于作者新近提出的一种混合塑性硬化准则和临界状态土力学理论建立了一个三维形式表述的适于饱和黏性土的弹塑性双面模型,此硬化准则是著名的M asing方法在三维应力空间中的推广。该模型的二维形式已采用饱和黏性土样室内动态三轴不排水剪切试验的结果进行了验证并已在另文发表。本文所建的三维弹塑性动本构模型与一个半经验的孔隙水压力增长模式相结合,通过有限元程序ABAQUS*对一个循环荷载作用下的条形基础下部地基土层内的位移、应力分布和超孔隙水压力随时间的变化进行了分析,计算结果表明模型预测的地基土的力学响应是符合实际的。