Evolution of the capillary network in a reactive powder concrete during hydration process

Ultrasonic waves in echographic mode, combined with autogenous shrinkage measurements, were used to study the evolution of the capillary network of reactive powder concrete (RPC) from the time after the mixing. Two characteristic porous classes have been identified: the first, between 10 and 20 nm, begins when the material reaches its solid hyperstatic state, and the second about 1 or 2 nm. The first class is associated with the porous space between the C-S-H hydrate clusters and the second with the internal porosity of the hydrate. The evolution of the active capillary radius as a function of the degree of hydration allows us to understand the strong interaction between the capillary network size and the chemical activity given by the dissipated calorimetric power curve. Indeed, the maximum point of the chemical activity marks the transition of the first class of pores to the second one. Finally, measurements of electrical conductivity through RPC samples show that after the maximum of the dissipated power, the curve of this electrical conductivity presents the same evolution as the capillary radius. As the electrical conductivity clearly depends on the evolution of the capillary network, the similarity between the results confirms our analysis in pore classes.     

一种由MCS—8098单片机构成的工业控制单元

该工业控制单元采用MCS—8098单片机及组态灵活的STD总线形式和光电隔离等技术,既可单独使用,又可作为下位机通过串行通讯的方式和上位机组成多级分布式控制系统。     

通讯网的演进

在光纤高速传输技术、光交换与智能光网等与宽带接入、多媒体、3G等网络应用技术的推动下，建设基于IPv6协议的IP基础电信网成为可能。现在IP网正在朝着有序的、可管理的、有QoS保障的、可以支持各类业务的综合业务基础网演进。电信网也正在从网络接入层上、从长途网络层面上、从本地网络层面上、从固定网向含3G在内的移动网络等方面向支持IP技术及其综合业务的方面全面推进。     

欧洲能源现货交易市场结构分析

重点探讨了欧洲能源交易市场的市场结构和运作特点。欧洲能源交易市场是欧洲大陆上最大的能源交易场所,因此对市场参与者的管理是交易所的重要任务。欧洲能源交易市场建立了大量的规章制度来规范交易参与者的行为,以规避交易参与者联合操纵市场的风险。     

喷锚结合水泥搅拌桩在基坑支护中的应用

结合紫金苑工程实例,分析喷锚结合水泥搅拌桩在基坑支护中的应用并总结施工、监测经验。     

微机控制托辊管筒加工机床的设计

介绍了一种生产效率高、加工质量稳定、利用单片机控制液压传动系列带式输送机托辊管筒自动加工机床的设计过程。     

无约束淬火机目标温度神经网络预报

淬火、控制冷却的冷却速度和目标温度是关系到钢板性能的关键因素 ,但由于冷却过程的水量、水温、辊道速度等对冷却目标温度的影响属多变量非线性过程 ,用简单的解析模型通常精度较低 ,难以达到精确控制的要求。采用人工神经网络技术对无约束淬火机目标温度进行快速预报 ,结果表明 ,预测精度高 ,快速准确     

荆门热电厂4号炉高温再热器超温控制

分析了荆门热电厂4号炉高温再热器超温的原因，提出了减缓超温程度的措施，并取得了较好的成效。     

Neural Network Feedback Control: Work at UTA’s Automation and Robotics Research Institute

This is an outline of research in neural networks for feedback control done since the mid 1990s at the Automation and Robotics Research Institute (ARRI) of The University of Texas at Arlington (UTA). It shows how the developments of Intelligent Control Systems based on neural networks have followed three main generations. This statement provides a short, broad-brush perspective on the development of intelligent neural feedback controllers.     

浅谈机械化施工的组织管理与设备调配

结合公路机械化施工的意义和作用，介绍了施工机械调配的基本要求，阐述了机械设备的运行规律及其调配原则，提出了主导机械的调配方法及相关注意事项。