智能变电站测控功能集中式冷备用装置的研制

智能变电站测控装置目前没有备用,测控装置故障或异常时,相应电气间隔将失去测控功能。测控装置双重化方案曾进行过一些试点,实现技术已趋于成熟,但另增一套测控装置的成本过高阻碍了其推广应用。采用测控功能的集中式冷备用技术,能够以较低的成本解决测控装置无备用难题。文中详细描述了集中式冷备用所使用的虚拟测控装置的模型辨识技术、一致性验证技术,以及集中式备用解决方案。     

基于随机秘钥蝙蝠算法的多行设施布局设计

针对行内纵向通道数量和位置具有不确定性的多行设施布局问题,建立了以最小化物流强度、最小化搬运设备空载运行强度及最大化相互关系为设计目标的布局优化模型,并针对所建立的模型提出了一种基于映射规则的随机秘钥蝙蝠算法。在蝙蝠算法中引入随机秘钥编码思想,定义了基于随机秘钥编码的蝙蝠位置向多行设施布局组合解的映射规则与映射步骤,使算法在不进行离散化处理的前提下,可以在连续空间上执行,并在组合空间上映射出码长不同的布局方案。最后,以一个多行设施布局问题为实例,采用所提出的随机秘钥蝙蝠算法进行求解,证明了算法的优越性。     

岩体工程勘察中的量化描述方法

不连续面的存在对岩体的工程性质有极大的影响,而目前工程勘察对于岩体及其中的不连续面的描述存在诸多不足。本文介绍了一些针对岩体及其不连续面的量化描述方法。岩体的量化描述包括取芯率、块状取芯率、岩石质量指标、裂隙指数等。不连续面的描述包括倾角、张开程度、不连续面的平滑程度等。并指出只需对现有的岩石钻探的工艺进行少量改进,即可获得大量的岩体及不连续面的信息,可为工程建设提供可靠的依据。     

深圳证券交易所营运中心抬升裙楼施工阶段应力监测与分析

深圳证券交易所营运中心的抬升裙楼采用超长巨型悬挑钢桁架结构体系,具有悬挑跨度大、受力复杂、临时支撑卸载难度大的特点。采用自主研发的基于有线应变数据采集与无线信号传输的应变监测系统,在施工阶段,尤其是在卸载过程中,对抬升裙楼关键构件进行实时应力监测。通过长期应变监测数据统计分析、双轴对称测点应力对比分析以及焊接对结构局部应力增量影响试验研究,对施工中的抬升裙楼进行实时安全评估。结果表明：卸载过程中裙楼结构受力稳步转换;龙骨焊接施工产生的焊接残余应力对焊接区域附近的结构局部应力增量有显著影响。     

超声振动对含LPSO结构的Mg98Y1.0Ni0.5Al0.5合金显微组织与力学性能的影响(英文)

低Y、Ni含量的LPSO结构增强镁合金具有低成本、优异力学性能的特点。为进一步提升其综合力学性能,掺杂Al元素及熔体超声振动处理是可行的途径。通过扫描电子显微镜、能谱分析、透射电子显微镜、X射线衍射和纳米压痕测试研究掺杂Al元素后低Y、Ni含量的Mg98Y1.0Ni0.5Al0.5合金的显微组织,对比超声振动对显微组织与力学性能的影响。掺杂Al后LPSO结构的含量降低,且在块状LPSO结构相邻处析出圆整的Al₂NiY相。Al₂NiY相与LPSO结构和Mg基体在界面处均不共格。通过对熔体施加超声振动处理后,Al₂NiY相被有效细化为短片状,并均匀分布在基体中,阻碍微裂纹的产生和扩展,从而提高Mg₉₈Ni_0.5Y_1.0Al_0.5合金的力学性能。与未经超声处理Mg₉₈Ni_0.5Y_1.0Al_0.5合金相比,其极限抗拉强度和伸长率提升至187 MPa和7.9...     

基于VPX 总线的高级计算平台的研究与设计

针对用户对高性能、高带宽、抗恶劣环境计算平台要求越来越高的现状,提出一种基于多协议交换(versatileprotocol switch,VPX)总线设计的高级计算平台。介绍VPX总线的发展历史,指出基于VPX总线的高级计算平台需要解决的关键问题,给出其架构,详细讨论其具体设计方法,并在不同环境下进行了长时间测试。测试结果表明:该设计平台性能高、带宽高、稳定性好、抗干扰能力强、维护方便,适用于恶劣工作环境。     

A chromium carbide coating in-situ formed on C/C composites by the novel reactive wetting strategy to enhance oxidation resistance

A chromium carbide (Cr-C) coating in-situ formed on the C/C substrate is successfully prepared by a novel reactive wetting strategy. The interfacial microstructure and oxidation resistance of coated C/C composites are investigated in detail. The as-prepared coating mainly consists of Cr₂₃C₆ and Cr₇C₃, forming a tight joining with the C/C substrate. Compared to uncoated samples, the oxidation weight loss of coated C/C composites is substantially reduced at high temperatures. Furthermore, the hardness of coated C/C composites is significantly increased, enhancing their ability to resist external damage. This reactive wetting strategy can also be used to prepare uniform coatings on C/C composites with complex grooved structure or large size. Surprisingly, coated C/C composites possess a low weight gain of 3.7% due to thin coating (< 10 µm), which can maintain their advantage of low density.     

Synthesis,morphological and thermomechanical characterization of light weight silica foam via reaction generated thermo-foaming process

Low-cost thermo-foaming technique involving sucrose dehydration reaction with H₂SO₄ has been used for ceramic foam processing. The heat and gas generated during the reaction induces a thermo-foaming effect in the sucrose-ceramic mixture. This converts the sucrose-ceramic slurry into a carbonaceous porous ceramic-scaffold. The converted carbon is seen to agglutinate with the ceramic particles. During sintering, they are removed subsequently, thereby enlarging the pores. Influence of solids-loading, sintering temperature and H₂SO₄ concentration on the foaming behaviour, pore morphology and thermo-mechanical properties are studied. The fabricated silica foams are found to have porosity within the range of 70 %? 90 % and compressive strength of 0.8–2.8 MPa. The extreme porosity of the silica foams and their intercrystallite pores within the struts results in the low thermal conductivity (0.0943 Wm^?1K^?1) of the specimens. The fabricated foam is seen as a promising material for insulation applications like catalyst supports, filters and bio-scaffolds.     

A 2D image-based multiphysics model for lifetime evaluation and failure scenario analysis of self-healing ceramic-matrix mini-composites under a tensile load

We propose a multi-physics numerical model for a self-healing ceramic matrix mini-composite under tensile load. Crack averaged PDEs are proposed for the transport of oxygen and of all the chemical species involved in the healing process and studied in the dimensionless form to perform the most appropriate discretization choices concerning time integration, and boundary conditions. Concerning the fibres’ degradation, a slow crack growth model explicitly dependent on the environmental parameters is calibrated using a particular exact solution and integrated numerically in the general case. The tow failure results from the statistical distribution of the fibres’ initial strength, the slow crack growth kinetics, and the load transfer following fibres breakage. The lifetime prediction capabilities of the model, as well as the effect of temperature, spatial variation of the statistical distribution of fibres strength, and applied load, are investigated highlighting the influence of the diffusion/reaction processes (healing) on the fibre breakage scenarios.