外掺轻烧氧化镁混凝土的长龄期自生体积变形研究

氧化镁具有延迟性膨胀特性已被工程界所认识并应用于补偿大体积混凝土的温降收缩,因此,保证氧化镁混凝土的长龄期体积稳定性是非常重要的。主要研究了外掺轻烧氧化镁混凝土自生体积变形的长期发展规律。研究结果表明,混凝土中轻烧氧化镁的膨胀开始时间在1~3 d左右,终止时间随粉煤灰掺量的增加而延长;混凝土强度对氧化镁的膨胀变形起到了约束作用,水胶比越小,外掺氧化镁混凝土的后期体积膨胀变形越小;粉煤灰对混凝土中氧化镁的膨胀作用具有抑制效果,从长期发展规律来看,外掺轻烧氧化镁混凝土可通过调整粉煤灰掺量和氧化镁掺量来控制膨胀速率与膨胀量,以保证其长龄期体积稳定性。     

我国道路桥梁路基施工技术的应用分析

道路桥梁的基础——路基,不仅需要承担道路自身的巨大重量,还需要承担路面行驶车辆对路桥的压应力作用,路基的建设质量会直接影响整个道路桥梁施工的最终质量。本文对路基施工的特点、要点及施工技术进行了分析。     

关于城市公共交通的研究

以绵阳市公共交通为研究对象进行了调查,分析了该市公共交通线路存在的问题,针对性地给出了相应处理意见,提出＂一主多分＂城市格局构想及设立公交专用道等建议,以期改善城市拥堵状况,构建快捷方便的交通网络。     

在水准测量中利用“差数法”来计算和检核

主要介绍在水准测量中,用一种新的方法来计算和校核。这种方法称为"差数法",它利用常数213(313)替代尺常数4787(4687)进行计算和检核。之所以称为"差数法",是因为313=5000-4687或213=5000-4787.差数就是313(213)和尺常数4687(4787)一样,水准测量的计算和检核的方法差数313(213)一样做到。尽管在计算和检核方面它们都一样重要,有时"差数法"在快速度和准确度上更胜一筹。我们能用更少的时间完成同样的工作量。多年来的实践表明这种算法是切实可行的。     

A study on the spread of fire caused by the stack effects of patio—A computer modeling and a reconstruction of a fire scenario

This study reported an actual building fire incidence for a ten-story building that occurred in Taiwan in 2008. Due to the stack effects the fire occurred on the third floor spread through the patio in a short time to the upper floors and caused three deaths in a tenth floor apartment. This study also attempted to reconstruct the actual fire scenario using computer simulation. The spread of the fire to the combustibles due to hot smoke was accounted for in the simulation. Variation of the fire scenario and the factors causing the fire spread were studied. It was found that an initial fire size below 1.0 MW would not generate sufficient hot smoke to cause fire spread despite the stack effects. However, any obstructions in the patio such as window shading has been found to cause heat accumulation that would aggravate the fire spread problem. The presence of a canopy at the top of the patio can cause higher concentration of smoke for the upper floors. The simulation results are found to be in good agreement with the actual incidence. Moreover the simulation results also show that when the fire spread through the patio the initial fire size of 1.0 MW at the fire site can grow to a building fire of 300 MW.     

援塞内加尔国家剧院

援外工程援外工程作为中国建筑对外输出的典型类型,具有其特定的重要性和代表性。援塞内加尔国家剧院作为中国与塞内加尔恢复建交后的最重要的援外项目,其建筑形象的文化性和建筑设计的高完成度得到了很好的统一。剧院位于塞内加尔共和国首都达喀尔,总建筑面积20671m~2,是一座融歌舞表演为主,适当兼顾会议、电影放映等多功能使用的国家级剧院。设有1800座观众席。由于投资方为中国商务部援外司,并不具备工程方面的经验,设计人要从最初立项、考察与搜资、与外方沟通,到制定项目任务书、方案设计、施工图详细设     

Chemisorption of estrone in nylon microfiltration membranes: Adsorption mechanism and potential use for estrone removal from water

Estrone is a representative steroid estrogen contaminant that has been detected in effluents from sewage treatment facilities, as well as in surface and ground waters. Our study shows that estrone can be readily removed from water via a unique chemisorption mechanism using nylon microfiltration membranes. Experiments on a laboratory in-line filtration system showed instant removal of estrone from 200 μg/l aqueous solutions by 0.45-μm nylon membranes (ca. 35 L per m² membrane). Comparisons with 0.45-μm PVDF, PTFE and glass microfiber membranes suggested that the significant estrone adsorption in nylon membrane should be predominately driven by a different mechanism rather than common physical adsorption. Fourier transform infrared spectroscopy study on nylon membranes and a model compound, N-methylacetamide, showed that the significant adsorption originated from the hydrogen bonding between terminal -OH groups on estrone molecules and nucleophile -CO groups in amide groups of nylon 6,6. The saturated nylon membrane showed very low leachability in ambient water, while it could be effectively regenerated in alkaline or ethanol solutions. Preliminary reusability study showed that the membrane maintained a consistent adsorption capacity for estrone during ten cycles of reuse. The chemisorption-based polymeric adsorption may provide a new alternative approach for removing estrone and potentially other trace organic contaminants from water.     

法国驻华使馆新馆解读

背景1.北京使馆区的变迁北京使馆区是世界各国驻中国的大使馆所在区域,历史上曾位于北京城前门外的东交民巷.随着历史的发展和变化,从方便规划和保障安全出发,外国驻华使馆主要分布在北京的3个使馆区,即建国门使馆区、三里屯使馆区和亮马河使馆区.它们也分别被称作第一使馆区、第二使馆区和第三使馆区.未来,望京地区将是规划中的第四使馆区.     

地被植物在屋顶绿化中的运用——以武汉市武昌区黄鹤楼周边屋顶绿化项目为例

城市的生态化是后工业时代对城市综合功能提出的必然要求,屋顶绿化的发展已成为趋势。因地制宜、有针对性地分选择绿化植物是屋顶绿化建设成败的关键。该文章结合黄鹤楼周边屋顶绿化工程,认为可以通过对地被植物的合理配置以及控制性的造景,使屋顶绿化获得理想的景观效果和生态效应。     

基于ANSYS的压力容器应力分析

通过ANSYS软件模拟,得到模型在压力载荷下的数值计算结果,选择多条具有代表性的路径,应力线性化,得到主要应力、主要应力+次要应力等各项指标,与规范进行比较,确保了容器的安全可靠性。