膨润土土工合成材料的研究

将所合成的相对分子质量约为3~4万的聚丙烯酰胺(PAM)与甲醛反应使之羟甲基化,然后将羟甲基化聚丙烯酰胺和单体丙烯酰胺(AM)脱水缩合,得到产物改性聚丙烯酰胺.适宜的反应物摩尔比n(PAM)∶n(甲醛)∶n(AM)=1∶0.6∶0.6,羟甲基化转化率可达99%以上,丙烯酰胺转化率可达93%以上.改性聚丙烯酰胺以过硫酸铵为引发剂,N,N′-亚甲基双丙烯酰胺为交联剂在室温下发生交联反应.其优点是交联速度快、聚合放热温度低、在侧链发生交联反应、抗水解能力强,吸水膨胀倍数与膨润土相当.将改性聚丙烯酰胺与膨润土混合(其中膨润土质量约占70%)制成的膨润土土工合成材料,其体积膨胀率为190%,基本达到我国建筑行业标准实用要求.该产品经久耐用,为土工合成材料的制备技术探索了一条新路.     

A new direct version of the Cook-Mayne method for wind pressure probabilities in temperate storms

The original Cook-Mayne (CM) method for obtaining a wind pressure or load of a prescribed probability is reviewed. A new direct calculation method is introduced. This does not require either Monte Carlo simulations or the assumption that extreme pressures conform to the ultimate Fisher-Tippett Type I asymptote. The required value is calculated directly with no intermediate stages. The new method still relies on the original assumptions that both the pressure coefficient and the wind dynamic head have extremes which conform to the ultimate FT1 asymptote.Violation of these two assumptions is studied in some cases where calculations based on these assumptions are compared with exact results. The direct CM method is found to retain accuracy in spite of departures from the assumptions and therefore can provide a robust design tool.     

桥头跳车产生原因及防治措施

简述了桥头跳车的普遍性及危害,从结构、设计、施工三方面分析了桥头跳车产生的原因,深入探讨了桥头跳车的防治措施,提出了换填处理,采用半刚性基层等桥头跳车的补救方法,以更好地解决桥头跳车问题。     

Modern Geodetic Methods of Constructing Digital Three-Dimensional Models for the Monitoring of Engineering Structures

A brief review of modern surface geodetic methods used in monitoring projects ranging in size from several tens of meters to several kilometers is presented. Buildings and various engineering structures, as well as slide-prone types of natural entities, pulsating glaciers, etc. are classed among these entities. Use of digital three-dimensional models of observable entities, which are developed from results of laser scanning and/or a digital photogrammetric survey, is proposed.     

Ultraviolet light inactivation of protozoa in drinking water: a Bayesian meta-analysis

To assess the dose of UV light needed to achieve specified levels of Giardia spp. cysts and Cryptosporidium spp. oocysts inactivation in drinking water, a Bayesian meta-analysis is used to analyze experimental data from several studies. Of the 20 studies identified by an extensive data collection effort, 14 (five reported experiments on Giardia and nine on Cryptosporidium) were selected for analysis based on a set of criteria. A substantial amount of the log inactivation data are reported as greater than a given inactivation level (i.e., censored data). The Bayesian hierarchical modeling approach used in this study not only properly addresses the common concerns in a meta-analysis but also provides a robust method for incorporating censored data. Different statistical models will result in different estimates of the UV doses needed to achieve a specific inactivation level. The Bayesian approach allows us to present the uncertainty in terms of risk, which is better suited for supporting US EPA in developing regulations.     

现有工程招标评标的不规范现象及对策

工程项目评标是招标工作的主要环节,评标决策方法的科学、客观与否,直接关系到招标工作的成功,保证公开、公平、公正地选择中标人,是建筑市场环境的综合反映。现有工程招标评标的不规范现象,其根源就是标底的存在。随着市场经济的发展,采用“最低价中标”的方法是大势所趋。但“最低价中标”原则却遭到了许多人的反对。投标人为了不使总报价过高,对在施工过程中无望增加工程量或可能减少工程量的项目压低报价。同时,有些投标人不惜一切手段了解专家名单,长期拉拢某些专家,影响评标的科学性和公正性。规范招投标行为,提高招投标透明度,实质是通过公开、公平、公正的招投标活动,将建立高效、规范的管理体系的过程法律化。     

房屋框架抗震墙与底层侧移刚度比控制分析

结合工程实际中的一些问题和建筑抗震设计规范，提出了底层框架抗震墙砖房第二层与底层侧移刚度的控制措施指标和设计方法，达到合理布置抗震墙，减少底层的薄弱程度，提高底层框架房屋的抗震能力的目的。     

光的教堂与朗香教堂形态结构关联研究

本文着眼于体验视角,分析光的教堂与朗香教堂中各存在主体的构成及其相互关系、各存在主体分别对应的空间形态及其相互关系,以及这两组关系之间的关联:进而通过对朗香教堂空间形态结构的图式分析,透过形态表象的差异,揭示光的教堂在空间形态结构方面与朗香教堂的关联性;从一侧面展示当代教堂建筑形态生成的某些一般性规律。     

混凝土结构耐久性的整体论

从分解论而不是从整体论角度研究混凝土耐久性，对改善混凝土结构的耐久性是事倍功半，甚至是无济于事的。国内混凝土结构过早劣化的起因是微裂缝和孔隙的存在。改善混凝土的匀质性，减少或避免混凝土早期开裂，才能获得延长结构服务寿命的整体效果。     

浅谈公路桥头跳车产生原因及防治措施

分析了引起桥头跳车现象的原因,并针对这些原因提出了桥头跳车的防治措施,以合理缩小造价和缩短施工工期,有效避免桥头跳车病害的产生,保证行车舒适与安全。