Experience with Siberian Centralized Dispatch Regulation regarding location determination of damages sustained by intersystem high-voltage transmission lines

A set of measures that can be implemented by the Relay-Protection and Automated-Equipment Service for Centralized Dispatch Regulation (CDR) in Siberia to determine the location of damage sustained by inter-system 550-and 220-kV transmission lines maintained by the United Power System (UPS) of Siberia, and the methodology and technology of damage-location determination (DLD) are described. The damage sustained by the 500-kV high-voltage lines (HL), and the accuracy of DLD relative to zero-sequence emergency parameters are analyzed statically. __________ Translated from élektricheskie Stantsii, No. 5, pp. 59–62, May, 2006.     

双头螺栓失效分析

与汽车电机装配在一起的双头螺栓在拧紧后不久便发生断裂。采用扫描电镜、化学分析、金相检验等方法对失效件进行了检测，同时又进行了氢脆试验验证。结果表明，螺栓在进行表面酸洗及电镀时，氢向金属内部扩散和富集，当氢浓度达到一定临界值后，促使氢致裂纹的产生和扩展。在外应力的作用下，即出现氢脆现象导致螺栓断裂。     

用屏蔽暂堵技术封堵水平井裂缝性漏层

克拉玛依油田HW702水平井的大斜度段和水平段,将穿越纵向裂缝发育的二叠系佳木河组储层。为安全钻进和保护油层,用超细碳酸钙和磺化沥青复配后加入复合离子钻井液中成屏蔽暂堵的堵漏钻井液。室内用岩心试验,屏蔽暂堵后渗透率可降为0,暂堵深度小于3cm,可用酸化和射孔解堵。现场使用效果也很好,使HW702水平井顺利完钻,并获得工业油气流。     

The stability robustness determination of state space models with real unstructured perturbations

This paper considers the robust stability of a linear time-invariant state space model subject to real parameter perturbations. The problem is to find the distance of a given stable matrix from the set of unstable matrices. A new method, based on the properties of the Kronecker sum and two other composite matrices, is developed to study this problem; this new method makes it possible to distinguish real perturbations from complex ones. Although a procedure to find the exact value of the distance is still not available, some explicit lower bounds on the distance are obtained. The bounds are applicable only for the case of real plant perturbations, and are easy to compute numerically; if the matrix is large in size, an iterative procedure is given to compute the bounds. Various examples including a 46th-order spacecraft system are given to illustrate the results obtained. The examples show that the new bounds obtained can have an arbitrary degree of improvement over previously reported ones. This work has been supported by the Natural Sciences and Engineering Research Council of Canada under Grant No. A4396.     

Bridge design with reserve and residual reliability constraints

System reliability is evolving as an important design method for selecting components and topology. It should be used to investigate the original intact structure behavior as well as providing sufficient reserve capacity under likely accident and damage scenarios. Highway bridges are an area of special concern since effort to optimize the cost of construction may not provide adequate redundant capacity. The paper describes an example in which a typical girder bridge structure is optimized (both size and girder spacing) to achieve target system performance. System reliability constraints are imposed on the behavior of the intact structure under highway loads. Also, residual system reliability constraints are imposed to control safety under specified accident scenarios corresponding to damage and “lost” members due to corrosion, fatigue, fire or accidental collisions. An optimal design framework for controlling safety under all these life cycle situations is thus provided.     

基于改进PSO算法的结构损伤检测

结构的损伤检测常转化为求解约束优化问题,针对粒子群算法容易出现早熟问题,增大算法后期的粒子位置的改变量,从而增加粒子位置的差异,因而能够增强其在求解约束优化问题时抵抗局部极小的能力。两层刚架单损伤和多损伤识别的数值结果和收敛曲线表明了改进后的粒子群算法优于传统的带惯性因子的粒子群算法。三层框架结构的4种损伤工况的试验研究进一步说明了该算法应用于结构损伤检测领域的有效性。     

钢筋混凝土结构正截面强度计算理论的应用

简述了钢筋混凝土正截面强度计算理论的发展历程，介绍了其计算理论的特点及其存在的问题，并对今后需要进一步研究的问题进行了展望，为工程设计提供参考。     

吐哈油田葡北3-12井超长封固段固井技术

葡北3-12注气井位于吐哈盆地葡北构造带中断葡北1号构造．井深为3610m。针对该区块地层承压能力低，易漏失，油气水窜严重，常规固井方法无法满足固井要求的问题，该井采用三段三凝制、常规水泥浆和泡沫水泥浆体系固井，并采用重钻井液顶替技术．降低施工压力。该技术能保证固井候凝过程中井底压力平衡，施工安全。现场应用表明，采用常规水泥浆和泡沫水泥浆固井技术．提高了低压易漏井、长封固井段的固井质量，解决了水泥返高不足的问题；并通过一次常规固井工艺实现了全井封固，简化了施工工艺，节约了成本，经济效益和社会效益十分显著。该井封固优质段累计达2600m，优质率达85％，固井结果良好。     

油基钻井液的推广及循环利用

针对普通水基钻井液在钻进中强、强水敏性油藏时会造成储层污染、产量降低的问题,指出了油基钻井液在钻进该类油藏时的优势和其成本高、对生态环境有污染的缺点。为了大面积推广应用油基钻井液,重点介绍了油基钻井液的特性和稳定性影响因素,并通过室内评价证明了油基钻井液在油层保护中的良好效果,着重阐述了油基钻井液在王庄油田的现场应用情况,并探讨了油基钻井液的循环利用技术。研究结果表明,油基钻井液不仅具有良好的油层保护效果,而且具有较好的社会经济效益。     

钢纤维聚合物混凝土抗压本构关系

钢纤维聚合物混凝土是由聚合物混凝土基体和钢纤维共同组成的纤维增强复合材料，它的力学行为不仅依赖于聚合物混凝土基体的行为，而且与钢纤维的掺量、分散特征以及钢纤维的几何尺寸有关，本文将基于损伤力学原理研究在不同纤维掺量下的钢纤维聚合物混凝土的全程压力-应变曲线及其本构模型。