基于知识库的锅炉"四管"爆漏预报专家系统

从分析锅炉“四管”爆漏的特点出发，提出了基于知识库的锅炉“四管”爆漏预报专家系统。文中给出了系统总体结构模型和面向对象模型，并根据系统要求建立了数据库；积累案例形成案例库；获取专家经验及领域知识建立了规则库；依据知识层次结构建立了模型库；4库一体化形成专家系统。文中介绍了基于安全、基于规则和基于模型的预报推理方法，比较了各种预报推理方法的优、缺点，并提出了基于案例、规则和模型的混合推理，其优点在于能充分发挥各种推理方法的优势，克服各自存在的不足，能最大限度地找到问题的解。文中还讨论了贴近度的定义、表示和计算以及规则表示等问题。最后，给出了系统的功能和实现方法。应用证明：基于知识库的锅炉“四管”爆漏预报专家系统可以得到与专家同样的预报结果。图3参8     

微地震监测技术及其在油田开发中的应用

微地震监测是指将井下地震技术用于探测由于岩石内应力发生变化而引起的微地震事件，即将高灵敏度的地震传感器布放于压裂邻近的井中，连续记录因压裂引起的油气藏物理特性改变而产生的微地震活动。该技术用于油藏和气藏水力压裂裂缝的成图，通过对压裂过程中的微地震数据连续采集记录并实时处理，标定出微地震事件即压裂裂缝的位置。借助于微地震裂缝诊断，在压裂作业过程中可以有效地优化压裂和压裂方案设计，提供油气藏资源评价、油气藏趋替信息和未来钻井位置图，达到增产目的，并为二次勘探的规划提供依据。     

不锈钢渣油管道焊接裂纹产生的原因及对策

在炼油厂渣油管道更换安装施工中,发现管道的部分焊道出现了裂纹,为找出裂纹产生的原因,在实验室进行了模拟现场焊接试验,对所用焊条的化学成分进行了分析,认为焊条质量是造成裂纹的主要原因,并通过理论分析说明该裂纹为凝固热裂纹,相应提出了热裂纹的防治措施。     

活塞环槽镀铬层次裂纹产生原因及解决措施

针对活塞环槽镀硬铬后产生次裂纹现象,对可能的因素如:镀铬层厚度、磨削速度、冷却环境、磨削量、磨削工具等进行了分析。分析结果表明:以上因素均对次裂纹的产生有影响。通过改进镀铬层厚度设计及改进工艺方案,活塞环槽镀铬次裂纹问题得到解决。     

高温期滑模快速施工条件下的重力坝表孔长闸墩温控防裂

针对滑模快速施工条件下混凝土闸墩温控防裂问题,以官地水电站表孔闸墩为例,采用仿真计算方法预测并优化了该闸墩施工期温度和应力发展过程。结果表明,在混凝土所处环境温度较高、混凝土结构体积较大、约束大时,二级配混凝土、门槽、溢流面顶部附近的闸墩混凝土、间歇面四个区域易开裂,需加强水管冷却和表面保温措施。     

藤田矿区梓山组煤中硫分特征及其成因分析

基于藤田矿区地质资料进行综合分析研究,阐述梓山组煤中硫分特征,并对其成因进行分析。发现梓山中期海侵高潮时海水从西南方向浸漫至藤田,该期水体停滞所致的强还原条件是导致本区硫分形成的主要因素,另外煤层形成之后受到海相灰岩顶板影响使煤中硫含量增高且区内煤中硫分具有由西南至北东降低趋势。     

Using Discontinuity Method in Plane Thermoelastic Problems of Fracture Mechanics

The boundary element method is used for solving stationary plane thermoelastic problem for heat-conductive crack. The influence functions for a segment with elementary discontinuities of temperature, its normal derivative (an analogue of heat flow) and displacements are obtained. The results of test problem correspond to a physical picture of the process. The illustrative problem is devoted to a question about the necessity to take into account the heat conductivity of cracks in the longitudinal direction in the thermoelastic problems of fracture mechanics. Recommendation for choosing thermal model of the cracks for metal structures is made.     

Transient Thermoelastic Analysis of a Solid Cylinder Containing a Circumferential Crack Using the C–V Heat Conduction Model

This article presents the transient thermoelastic analysis in a long solid cylinder with a circumferential crack using the C–V heat conduction theory. The outer surface of the cylinder is subjected to a sudden temperature change. The Laplace transform technique is adopted to solve the one-dimensional hyperbolic heat conduction equation, and the axial thermal stress is obtained for the un-cracked cylinder in the Laplace domain. Then this axial thermal stress with a minus sign is applied to the crack surface to form a mixed boundary value problem in the cylindrical coordinate system. A singular integral equation is derived by applying the Fourier and Hankel transforms to solve the mode I crack problem. The transient thermal stress intensity factors are obtained by solving the singular integral equation numerically. The influences of thermal relaxation time, crack geometry, and Biot's number upon transient temperature distributions, axial stress fields, and stress intensity factors are analyzed.     

TWO-CRACK PROPAGATION PATHS IN A FUNCTIONALLY GRADED MATERIAL PLATE SUBJECTED TO THERMAL LOADINGS

Two-crack propagation paths in a ceramic/metal functionally graded material plate (FGP) under one-cycle temperature change of heating and cooling are considered. When the FGP is subjected to thermal shock, a single crack or multiple cracks often initiate on the ceramic surface during the cooling process and propagate in the FGP. Crack paths are influenced by the heating temperature conditions, a compositional profile of the FGP, the fracture toughness, interaction among multiple cracks, and so on. Transient thermal stresses are treated as a linear quasi-static thermoelastic problem for a plane-strain state. The crack paths are treated under fracture mechanics using the finite-element method. The effects of heating temperature conditions, a compositional profile of the FGP, the fracture toughness, and a crack space on the crack propagation pattern are discussed and are shown in figures.     

从运行情况谈混凝土面板坝的设计与施工

从沟后、西北口、天生桥、成屏、株树桥、天荒屏、鱼背山、小梅沙以及国外某些混凝土面板坝的运行情况，探讨混凝土面板坝的设计与施工有关问题。