高填方涵洞EPS板减荷施工技术研究

由于高填方涵洞受力过大,通常所设计的涵洞结构尺寸大、造价高、病害多。因此,在以往研究的基础上,通过室内外试验,将一定厚度的EPS板铺设在盖板涵顶部进行减荷,结果表明:EPS板能够显著减小涵顶土压力,试验测得涵顶土压力为土柱压力的0.28～0.47倍。同时,分析了EPS板在各种机械施工荷载作用下的受力情况,根据计算结果,提出了一套EPS板顶进行土体回填的具体施工技术,并在实际工程中验证了该套技术的可行性,不但保护了EPS板及达到减荷效果,而且保证了工程质量。     

武汉体育中心游泳馆供配电系统设计及可靠性分析

本文介绍了武汉体育中心游泳馆供配电系统设计,包括负荷分级、正常电源、应急电源、变配电系统组成等,重点对高、低压供配电系统的可靠性进行了分析,旨在对游泳馆类建筑电气设计起到借鉴作用。     

Long-term formation of microbial products in a sequencing batch reactor

Activated sludge in a sequencing batch reactor (SBR) is subjected to alternating feast-and-famine conditions, which may result in the enhanced production of microbial products: extracellular polymeric substances (EPS), soluble microbial products (SMP), and internal storage products (X_STO). In this work, the long-term formation of these three microbial products by activated sludge in an SBR is investigated using an expanded unified model with a parallel experimental study. We also use the model to compare the impacts in an SBR to those in a continuous-flow activated sludge system. The model captures all experimental trends for all components with solids retention time (SRT) for global steady state and within a cycle. At an SRT of 20 days, the active microorganisms constitute about 28% of the mixed liquor volatile suspended solids (MLVSS); the remaining biomass is comprised of residual inert biomass (X_I) of 40%, EPS of 31%, and X_STO of ∼1%. The active biomass becomes a smaller fraction with the increasing SRT, while the inert biomass becomes increasingly dominant. For soluble components, effluent chemical oxygen demand (COD) is dominated by SMP, which varies to some degree in a cycle, peaking as external substrate becomes depleted. Within the SBR cycle, external substrate (S) declines strongly in the first part of the cycle, and SMP shows a small peak at the time of S depletion. X_STO is the only biomass component that varies significantly during the cycle. It peaks at the time that the input substrate (S) is depleted. Simulation for a continuous-flow activated sludge system and comparison with an SBR reveals that the constant “famine” conditions of the continuous system lead to lower EPS and X_STO, but higher MLVSS and X_I.     

电动助力转向系统的建模与仿真技术

概述了电动助力转向系统(EPS)的结构和工作原理,并介绍了电动助力转向系统助力特性的设计方法。在分析了电动助力转向系统各组成部分数学模型的基础上,构建了基于Simulink的电动助力转向系统仿真模型。采用了PID和直流斩波控制策略对电动机目标电流进行闭环跟踪控制。仿真结果表明:所设计的助力特性较好地协调了转向轻便性和路感之间的矛盾,同时,电动机实际电流较好地跟踪了目标电流,从而验证了控制策略的有效性。     

Expanded Polystyrene Foam Formed from Polystyrene Beads Coated with a Nanocrystalline SiO2 Film and the Analysis of Its Moisture Adsorption and Resistance to Mechanical Stress

Conventional expanded polystyrene can absorb moisture, which significantly degrades its properties. In the present study, it was demonstrated that SiO₂ can be deposited on polystyrene beads before pre-expansion and molding steps. Under the applied test conditions, expanded polystyrene with nanocrystalline SiO₂ additives had approximately 10% lower moisture adsorption and an 8.4% better resistance to deformation. Expanded polystyrene analysis suggested that the observed improvements were caused by the hydrophobic nature of nanocrystalline SiO₂ and, even more importantly, because SiO₂ acted as an amalgamation catalyst and significantly increased adhesion between the expanded polystyrene beads during the expanded polystyrene molding process.     

Effects of fermentation conditions and homogenization pressure on the rheological properties of Kefir

In this study, the effects of fermentation conditions (temperature and time) as well as homogenization pressure on the rheology and EPS production in Kefir made from bovine whole milk were investigated. Results showed that the rheological characteristics and EPS production are affected significantly (p < 0.05) by the fermentation temperature but not by the incubation time. Furthermore, the homogenization pressure was found to influence significantly (p < 0.05) the rheology but not the production of EPS in Kefir.     

新型单相应急电源(EPS)的研制

针对目前EPS(Emergency Power Supply,EPS)应急电源切换速度慢的问题,提出了一种快速切换的单相应急电源的数字化解决方案.基于锁相原理,令EPS输出电压和市电电压的大小、频率、相位保持一致,用DSP实现了EPS的快速切换技术,同时提出了一种简单的蓄电池在线监测系统硬件实现方式.并设计了一台50 Hz,220 V/1.5 kVA的EPS应急电源,采用继电器切换,从市电出现异常时刻开始到切换完成时刻止,切换时间小于10 ms.     

框架剪力墙结构针对不同基层外保温施工技术

结合工程实践和施工经验,通过对框剪结构常见的两种不同基层进行外墙外保温施工的总结,介绍了工程中的施工做法,并提出了相应的施工质量控制措施,以保证节能工程质量及效果。     

自备应急电源的选择和应用

从各类常用自备应急电源的特点出发,简要阐述了选择自备应急电源类型的基本原则,给出了各类应急电源工程设计中的选型计算方法,为电气设计人员提供了选择依据。     

试论汽车EPS新技术发展动态

电动助力转向(ESP)技术是汽车领域近年来较快的技术之一,受传感器技术、电力拖动及控制技术的推动和汽车安全性、驾驶方便性等的需求拉动,国内外该技术的发展出现了许多新的动向。结合作者的研究实践,本文总计并分析了ESP最新研究成果及应用现状、重点从传感器、控制方式、助力电动机三方面介绍了EPS发展的关键技术,并讨论了EPS的发展趋势。