上海环球金融中心结构设计简析

上海环球金融中心是一座多功能、先进智能型的摩天大厦，建成后总高度达492米，为世界第一高楼。设计建造这一超级摩天大厦是一项复杂的系统工程，尤其在结构设计方面，如何选用最有效的结构体系，如何建立完善的计算模型，以及如何进行全面的计算分析都是结构设计的关键问题。本对上海环球金融中心的结构设计及施工方案进行了较全面的介绍。     

Vertical variations of particle number concentration and size distribution in a street canyon in Shanghai, China

Measurements of particle number size distribution in the range of 10-487 nm were made at four heights on one side of an asymmetric street canyon on Beijing East Road in Shanghai, China. The result showed that the number size distributions were bimodal or trimodal and lognormal in form. Within a certain height from 1.5 to 20 m, the particle size distributions significantly changed with increasing height. The particle number concentrations in the nucleation mode and in the Aitken mode significantly dropped, and the peaking diameter in the Aitken mode shifted to larger sizes. The variations of the particle number size distributions in the accumulation mode were less significant than those in the nucleation and Aitken modes. The particle number size distributions slightly changed with increasing height ranging from 20 to 38 m. The particle number concentrations in the street canyon showed a stronger association with the pre-existing particle concentrations and the intensity of the solar radiation when the traffic flow was stable. The particle number concentrations were observed higher in Test I than in Test II, probably because the small pre-existing particle concentrations and the intense solar radiation promoted the formation of new particles. The pollutant concentrations in the street canyon showed a stronger association with wind speed and direction. For example, the concentrations of total particle surface area, total particle volume, PM2.5 and CO were lower in Test I (high wind speed and step-up canyon) than in Test II (low wind speed and wind blowing parallel to the canyon). The equations for the normalized concentration curves of the total particle number, CO and PM2.5 in Test I and Test II were derived. A power functions was found to be a good estimator for predicting the concentrations of total particle number, CO and PM2.5 at different heights. The decay rates of PM2.5 and CO concentrations were lower in Test I than in Test II. However, the decay rate of the total particle number concentration in Test I was similar to that in Test II. No matter how the wind direction changed, for example, in the step-up case or wind blowing parallel to the canyon, the decay rates of the total particle number concentration were larger than those of PM2.5 and CO concentrations. For example, CO concentrations decreased by 0.33 and 0.69 at the heights ranging from 1.5 to 38 m in Test I and Test II, while the total particle number concentrations decreased by 0.72 and 0.85 within the same height ranges in Test I and Test II. It is concluded that the coagulation process, besides the dilution process, affected the total particle number concentration.     

中国的城市化水平有多高?——城市地理研究为什么要借助分形几何学?

类比于海岸线的长度问题 ,本文提出三个城市地理“问题” :(1 )河南省的城市有多少 ?(2 )北京市的人口有多少 ?以及(3)中国的城市人口比重是多少 ?由此引出城市规模分布和城市形态的分形几何问题 ,进而论证 ,由于城市和城市体系的无标度性 ,要客观地确定一个国家(如中国 )的城市化水平是不可能的 ,在实践中应当制定科学的统计标准。一个必然的结论是 :城市地理研究必须借助分形几何学     

巷道围岩最优恒阻支护计算方法

根据岩石和围岩的蠕变机理以及岩石流变控制原则,在实验研究的基础上,提出了新的岩石稳定蠕变准则,并建立起一个岩石最优恒阻支护计算方法。用这一计算方法能求出岩石恒阻支护的重要技术参数,即最优(小)恒阻支护力、围岩最大允许变形量、恒阻U型钢支架的截面积、联接螺栓的预紧力和直径及最优支护力的拧紧力矩。按最优恒阻支护计算方法设计巷道支护,可以达到经济且安全的最佳支护效果。文中应用了课题组近期岩石流变实验研究的结果:应力偏量第三不变量对岩石蠕变影响显著;岩石侧向蠕变的应力阀值比轴向蠕变应力阀值低20%～40%。这些结果的应用使巷道岩石支护的设计更趋于安全。     

Re-use of water treatment works sludge to enhance particulate pollutant removal from sewage

This paper attempted to study the feasibility of reusing water treatment works sludge ("alum sludge") to improve particulate pollutant removal from sewage. The main issues focused upon were: (1) the appropriate dosage of the alum sludge, (2) the appropriate operating conditions, and (3) the possible mechanisms for enhancement by adding alum sludge. Actual alum sludge and sewage were applied to a series of jar tests conducted under various conditions. It has been found that both the SS and COD removal efficiencies could be improved by the addition of the alum sludge, which was mainly attributed to the removal of relatively fine particles with a size of 48-200 microm. The appropriate dosage of the alum sludge was determined to be 18-20 mg of Al/L. Increasing the mixing speed or reducing the floc size of the alum sludge enhanced the SS and COD removal and the dispersed alum sludge could remove particulate contaminants with smaller size than the raw sewage. ToF-SIMS evidence revealed that the aluminum species at the surface of the alum sludge were effectively utilized for improving the SS and COD removal. It was postulated that the sweep flocculation and/or the physical adsorption might play key roles in the enhancement of particulate pollutant removal from sewage.     

Decay and termite resistance of plywood treated with various fire retardants

This study evaluated the ability of white and brown rot fungi and termites to decompose fire retardant-treated (FRT) or untreated-plywood by measuring mass loss. Plywood was manufactured using Ekaba (Tetraberlinia bifoliolata Harms.) veneers which were previously treated with either boric acid, borax, mono-ammonium phosphate (MAP), or di-ammonium phosphate (DAP). Plywood specimens were then subjected to fungal decay resistance tests performed according to Japanese Industrial Standard (JIS) A-9201 method using a brown-rot fungus, Fomitopsis palustris (Berkeley et Curtis) Murrill and a white-rot fungus, Trametes versicolor (L. ex Fr.) Quel. The specimens were also assayed against the subterranean termite, Coptotermes formosanus Shiraki to determine termite resistance. Boron and phosphorus chemicals used in the study increased the resistance of plywood panels against both fungal and termite attack. Plywood panels treated with boric acid and borax resulted in less mass losses when compared to MAP and DAP-treated specimens in decay and termite resistance tests.     

我国现行结构抗火设计的问题及对策

分析了我国现行的结构抗火设计方法存在的与实际情况相差较大的弊端 ,叙述了我国结构抗火设计方面的理论与实验研究现状 ,提出了解决结构抗火设计及其研究有关方面的方法与对策     

采暖、空调系统运行费用的计量

文章从能量转化与分配的角度阐述了采暖、空调系统运行费用发生的机理,论述了各种采暖、空调系统运行费用的计量方式,揭示了费用计量与系统节能之间的关键联系。     

双波截尾模型在建筑物能耗分析中的应用

建立了干球温度和含湿量的双波截尾模型，用温频法将建筑负荷简化为干球温度和含湿量的函数，构建了建筑负荷的分布函数，结合一实际工程进行了建筑能耗分析，结果表明用双波截尾模型确定空调机组的设计制热、制冷量是可行的。     

气候变化背景下滨海地区园林树种抗风性研究进展

随着气候变化的加剧，台风给中国滨海地区生态安全带来重大威胁，在众多应对措施中，抗风树种选择是风景园林规划的基础。在阐述台风对中国滨海地区危害的基础上，从风灾后的树木调查与评估、树冠抗风形态特征研究、树干抗风荷载应力和木材性质分析及树根根系结构特征4个方面综述了国内外抗风树种选择研究的现状和发展趋势，通过综合分析树木抗风性因子，为全面提升滨海地区园林树种抗风性，提出了常见园林树种抗风性评价和科学搭配树种抗风性群落的建议。