Influence of colloidal nanosilica on hydration kinetics and properties of CaO/CaSO4-activated slag binderOA

To solve the energy consumption and CO₂ emission during cement production, the new binders must be developed as an alternative to cement. CaO/CaSO₄-activated slag binder is an eco-friendly and safe cementitious material; however, its low strength during initial stages limits its applications. In this study,colloidal nanosilica(CNS) was employed as an additive to improve the strength of CaO/CaSO₄-activated slag binder, and the effects of CNS on the workability, hy...     

智能电网信息化应用能力指标体系的评估算法

随着国家智能电网建设的推进,亟需研究一套行之有效的评价体系和评估方法,对智能电网进行科学、合理、全面的评价,以便为智能电网的发展规划提供科学指导,为智能电网的运行管理提供决策依据。文章系统研究了智能电网信息化应用能力指标体系的评估方法,从5个层次构建了智能电网信息化应用能力评价指标体系,建立了基于层次分析法的指标体系评估模型,并提出了层次分析法中随机成对比较矩阵生成的一个抽样方法,最后,给出了智能电网信息化应用能力的评估算法。     

基于各向异性本构模型的隧道支护控制

为了采用传统的力学模型来描述各向异性条件下隧道的受力特征与变形分布规律,作者基于空间滑动面理论的各向异性弹塑性本构模型,通过C++编程形成动态链接库dll文件,进行了FLAC3D各向异性弹塑性本构关系的二次开发.模拟分析结果表明,在各向异性条件下,隧道锚杆受力呈非对称分布的状态,经破坏区锚杆加长后模拟分析,围岩塑性区明显减小,且锚杆受力趋向均匀.通过胶州湾隧道接线工程现场应用,基于各向异性本构关系的隧道关键区支护控制是可行的.     

风速波动情况下并网风电场内风电机组分组方法

以风电机组的分组方法为研究对象,采用风电机组间尾流模型并考虑风向变化对尾流效应的影响,研究了风电机组输入风速的计算方法,提出了风电机组的分组方法。考虑风速、风向随机波动的特点,提出利用三维相关系数矩阵对大型风电场风电机组分组的方法。通过研究表明:在根据风电机组的输入风速是否相同对风电机组分组时,风电场的输入风向是决定风电机组分组的主导因素;利用三维相关系数矩阵可方便查询风速和风向变化时风电机组分组情况,为建立风电场的随机模型,研究风电场的特性打下基础。     

一种改进型含吸收回路的准△源升压变换器

针对传统耦合电感网络变换器中漏感所导致的母线电压尖峰问题,在△源变换器的基础上,结合LCD吸收回路与箝位二极管的概念,提出具有母线电压尖峰吸收能力的准△源变换器电路拓扑。分析了传统△源变换器电压尖峰的产生原理,并将吸收回路对电压尖峰的抑制进行理论分析。与传统的耦合电感网络变换器的拓扑结构相比较,所提拓扑大大提高了升压能力,有效抑制了母线电压尖峰,降低了元器件的电压应力。运用MATLAB/Simulink软件对电路进行了仿真,并在仿真的基础上搭建了实验样机,实验结果与理论分析相一致,验证了改进型电路拓扑的可行性和实用性。     

基于UWB穿墙定位中NLOS误差的优化方法

针对室内定位中受非视距因素影响下的无线信号穿墙导致定位发生偏移的现象,因无线电信号传播中具有波动性强、易干扰的特点,采用抗干扰性强、穿透力高以及测距值优的超宽带技术采集测量数据。本文将信号穿墙推导公式与无线信号对数衰减模型融合处理采集到的距离值数据,通过衰减模型减少了穿墙时信号损失的能量,提高测距值的准确性,通过最小二乘法减少测距时的累计误差,提高定位精度。通过实际实验场景测试得出：本方法在穿墙环境下定位精度可达到0.28m,满足精度要求,可以为一般的位置需求提供服务。     

基于自适应非奇异终端滑模控制的电力系统混沌抑制

在一定条件下,电力系统会产生混沌振荡现象,影响电网的安全稳定运行.对电力系统四阶模型进行混沌振荡的动力学行为分析,并且设计了一种基于自适应非奇异终端滑模控制的控制器.在保证系统实现有限时间内收敛以及不产生奇异性问题的基础上,快速消除了四阶电力系统中的混沌振荡现象.针对四阶电力系统模型中阻尼系数和机械功率通常具有不确定性...     

Pattern Matching of Industrial Alarm Floods Using Word Embedding and Dynamic Time Warping

<正>Dear Editor,This letter proposes a new pattern matching method based on word embedding and dynamic time warping (DTW) to identify groups of similar alarm floods.First,alarm messages are transformed into numeric values that represent alarms and also reflect the relationships between alarm occurrences.Then,similarities between numerically encoded alarm flood sequences are calculated by DTW and groups of similar floods are identified via clustering.The effectiveness of the proposed method ...     

Underground space needs an interdisciplinary approach

During a very long period of time, civil engineers have been the only ones to be designated as the experts for underground space, while the planners and architects were the ones of the development at the surface. This silo approach to work is now a thing for the past in most major cities, but solving this fragmentation of the disciplines does not happen overnight. It first took a few thinkers to promote and publish on the subject, such as Edouard Utudjian, founder of GECUS in 1937, and also that planners abandon their ambiguous position on this invisible space, become part of multi-disciplinary teams and participate in the dissemination of new knowledge, particularly through some international associations such as ACUUS. With biennial scientific conferences dating back to 1983, the organization actively promotes since partnerships amongst all actors in the field of planning, management, research and uses of urban underground space in all its forms. The originality of ACUUS comes from its success in attracting public, private and university levels into a cohesive network of mutual cooperation, which is not so common in international organizations.