聚羧酸高性能混凝土减水剂的减水机理与分子设计

介绍了混凝土减水剂的发展和应用现状,通过介绍聚羧酸高性能混凝土减水剂的减水机理,分析了聚羧酸减水剂的分子设计原则和合成制备研究方向,并提出了聚羧酸减水剂的复配研究问题.     

混凝土高性能减水剂的发展现状与展望

介绍了混凝土减水剂的研究现状,讨论了目前减水剂研究和应用中存在的主要问题,从机理研究、分子设计和原料选择等方面提出对混凝土高性能减水剂研究的思考与展望。     

高性能减水剂的研究现状与展望

本文概述了国内外高性能减水剂的主要性能及发展现状,介绍了高性能减水剂的种类与组成,提出了有关高性能减水剂的研究内容及今后研究方向。     

聚羧酸系高性能减水剂的研究现状与发展方向

聚羧酸系高性能减水剂是减水剂的新品种,具有很多良好的使用性能。介绍了聚羧酸系高性能效减水剂国内外研究现状、目前3种不同合成方法的研究现状及优缺点、作用机理的研究,提出一些亟待深入研究的问题及聚羧酸系高性能减水剂今后的研究方向。     

JY-PCA型聚羧酸系高性能减水剂合成与性能研究

介绍了JY-PCA型聚羧酸系高性能减水剂的合成,重点研究了该减水剂的性能。研究表明,JY-PCA型聚羧酸系高性能减水剂具有良好的减水效果与保坍性能,与传统萘系减水剂相比,聚羧酸系高性能减水剂可以明显改善混凝土的收缩性能。     

高性能混凝土中聚羧酸系高性能减水剂的应用

总结了聚羧酸系高性能减水剂的优点,介绍了聚羧酸系高性能减水剂在工程中的应用,分析了存在的问题,并提出了应对措施,从而使聚羧酸系高性能减水剂更好地满足工程使用要求。     

聚羧酸高性能减水剂在桥梁工程中的应用分析

首先针对聚羧酸高性能减水剂的特点进行了阐述,并在此基础上通过相关的桥梁工程实例,介绍了聚羧酸高性能减水剂的试验应用,以及在该桥梁工程中的使用,最后就聚羧酸高性能减水剂使用过程中的问题和解决方法进行了阐述。     

高性能胶凝材料与高性能混凝土

本文简要介绍了高性能水泥、超细无机掺合料、高性能减水剂的性能、使用条件和近期情况。在使用高性能减水剂配制高性能混凝土时，还必须使用高性能胶凝材料，才能保证其质量，达到预期的目的．     

高性能胶凝材料与高性能混凝土

本文简要介绍了高性能水泥、超细无机掺合料、高性能减水剂的性能、使用条件和近期情况。在使用高性能减水剂配制高性能混凝土时，还必须使用高性能胶凝材料，才能保证其质量，达到预期的目的．     

聚羧酸系KS-JS高性能减水剂的主要性能特点与工程应用

主要介绍聚羧酸系KS-JS高性能减水剂对广东、四川多种水泥的适应性与混凝土主要性能特点的研究与工程应用实例,并与氨基磺酸盐、脂肪族、萘系等高效减水剂做了对比试验,表明KS-JS具有独特的优点,是一种安全、绿色环保型高性能减水剂。     

浅谈住宅一户一表生活给水的设置

随着商品经济的发展,各户轮值抄表计费方式越来越不被民众所接受,“一户一表”是民心所归,是自来水收费体制上的一次重要改革,势在必行。详细地介绍了“一户一表”设置的几种方法和表位设置的形式,并对其发展趋势及方向作了详尽地分析,指出“一户一表”的设置必将沿着外墙式、水表间式表位设置,最终向IC卡(TM卡)式、远传水表电脑计量收费方式发展。文中还对“一户一表”的水力计算进行了分析,提出了“一户一表”设置的水力条件。     

太阳能热水器与高层住宅一体化结合的建筑策略

太阳能热水器在建筑中已有大量应用,但与高层住宅的结合问题一直没有得到较好的解决。从建筑角度提出几种与高层住宅的一体化结合策略:例如"屋顶集中式"、"两段式"和"均分式"等三种方式。并分别从系统形式、集热器安装、水箱设置、管道井设置等几方面分析其具体做法和应用的优缺点。     

Prevalence of vaccine-derived polioviruses in sewage and river water in South Africa

Polioviruses (PVs) are not associated with waterborne transmission to the same extent as many other enteric viruses. However, they are typically transmitted by the faecal-oral route, which implies that the risk of infection by exposure to the viruses in water cannot be underestimated. The risk appears particularly high for rural communities, which use sewage-polluted river water for domestic purposes. Thus, the presence in the environment of highly evolved, neurovirulent vaccine-derived poliovirus (VDPV) strains in the absence of polio cases would have important implications for strategies to terminate immunisation with oral poliovirus vaccine (OPV) following global polio eradication. The aim of the current study was to determine the prevalence of VDPVs in selected sewage and river water samples collected from 2001 to 2003, and to construct phylogenetic trees of the partially sequenced 5'untranslated region (5'UTR) and the VP1 region of the genomes to deduce the genetic relatedness between the PV strains. Using the monolayer plaque assay, 703 plaques from sewage and 157 plaques from river water samples were analysed. Application of a RT-multiplex PCR revealed that 176 of these plaques were non-polio enteroviruses, and 49 were PV isolates. The Sabin-specific RT-triplex PCR revealed the presence of 29 Sabin PV type 1, 8 Sabin PV type 2 and 12 Sabin PV type 3 isolates. The 5'UTR and the VP1 region of 13 PV type 1, 7 PV type 3 and 6 PV type 2 isolates were partially sequenced. The majority of the OPV isolates (24 out of 26) displayed close sequence relationships (>99% VP1 sequence identity) to the parental Sabin PV vaccine strains and were classified as "OPV-like viruses". Two isolates (D1 08/28 and OF1 05/21) were found to be highly divergent and were classified as "suspected" VDPVs. Isolate OF1 05/21 (a "suspected" VDPV type 1) showed more than 0.9% divergence in VP1, whereas isolate D1 08/28 (a "suspected" VDPV type 2) showed 1.4% divergence in VP1 from the parental Sabin PV vaccine strains. As with most of the other OPV-like isolates, these "suspected" VDPVs were carrying mutations, which have previously been associated with reversion of the attenuated Sabin PV strains to increased neurovirulence. It was estimated that the total period of replication for the two "suspected" VDPVs was between 12 and 16 months. In conclusion, this study provided new and relevant information on the prevalence of "suspected" VDPVs in sewage and river water, and opened the way to assess the possible broader significance of the findings reported here.     

钢筋混凝土倒锥壳水塔标准图集（04S802）简介

本文简要介绍"钢筋混凝土倒锥壳水塔标准图集"(04S802)国标集修编和所考虑的问题.     

Comparison of self-organizing maps classification approach with cluster and principal components analysis for large environmental data sets

Three classification techniques (loading and score projections based on principal components analysis (PCA), cluster analysis (CA) and self-organizing maps (SOM)) were applied to a large environmental data set of chemical indicators of river water quality. The study was carried out by using long-term water quality monitoring data. The advantages of SOM algorithm and its classification and visualization ability for large environmental data sets are stressed. The results obtained allowed detecting natural clusters of monitoring locations with similar water quality type and identifying important discriminant variables responsible for the clustering. SOM clustering allows simultaneous observation of both spatial and temporal changes in water quality. The chemometric approach revealed different patterns of monitoring sites conditionally named "tributary", "urban", "rural" or "background". This objective separation could lead to an optimization of river monitoring nets and to a better tracing natural and anthropogenic changes along the river stream.     

Amenagement des exutoires de ballastieres en eau en communication directe avec les rivieres

Disused alluvial sand and gravel quarries have created water surfaces sometimes directly connected through a channel with adjacent streams. The flowing of gravel-pit water into a river causes a rise in temperature, particularly in summer, thus inducing hydrobiological exchanges. In order to reduce the effects of gravel-pit water discharging into streams, two types of equipments have been designed and carried out.

-First type of equipment: concrete “moine” devices having a threefold function: they stabilize the outlets which tend to open out—during the hot season they connect the colder water in the gravel-pit with the stream water, “acting then as a drain-trap”.—Lastly they allow to “control” the level of water surfaces by drainage.

-Second type of equipment: filtering dams. These are intended to prevent fish and fry exchanges while ensuring the hydraulic continuity between water surfaces and streams.

This note gives an account of the work carried out in the Bresle valley (Seine-Maritime, Somme, Oise) and defines the technical data, equipment conditions and results obtained with respect to this work. These results have been found satisfactory. Monitoring is required to be sure that they will efficiently operate over long periods of time.     

Assessment of soil and groundwater impacts by treated urban wastewater reuse. A case study: application in a golf course (Girona, Spain)

Starting in July 2000, treated wastewater of urban origin has been used for the "Serres de Pals" golf course irrigation (Girona, Spain). To evaluate if the soil and the aquifer underneath are affected by the utilization of this type of water, samples have been taken along a period of several months from the wastewater treatment plant, the stabilization lagoon, groundwater and soil profiles. Analyses have been performed for total coliforms and aerobic bacteria, soil water pressure and soil water content as well as chemical analyses of the irrigation water, aquifer and water of the vadose zone. Soil profiles taken at several times during the study indicate the absence of coliforms except for a short period during summer. In the vadose zone an increase of more than 1000 mg kg(-1) of NaO(2) in the top 60 cm of soil was observed while Cl(-) concentration in the aquifer reached up to 1200 mg l(-1) ten months after starting the irrigation.     

Herstellungs- und Bemessungsgrundlagen für einen verlaufsgesteuerten Trinkwasserbrunnen als Pilotversuch an einem Standort in Krefeld

For the first time the exploration of potable water by means of a curved horizontal well was performed. This new well type has been installed in a shallow, coarse grained aquifer of pleistocene age at a site of the water works of the city of Krefeld “In the Elt”. The aquifer is characterized by a high transmissivity and preferential flow along gravel beddings as well as by a low thickness of the water bearing strata. The installation for conventional horizontal wells was assumed to be uneconomic. The new well type was installed by using the horizontal directional drilling method and washpipe technology. For testing purposes two types of screens have been completed so that a joint or a single discharge was possible. The screen types are continuously slotted stainless steel pipes and ductile porous polyethylene pipes. The well development could be done according to methods which are well known in Northern America. The aquifer gravel pack was developed autostable. Pumping tests and a flourescent tracer test were carried out proofing the results of the quantitative analytical engineering concept. The behaviour of well hydraulics may be described by steady state and transient methods.