大体积混凝土温度裂缝的控制措施探讨

大体积混凝土温度裂缝是一个施工难题,为从源头防止产生温度裂缝,从理论上阐述了大体积混凝土施工温度的预控。分析各类裂缝产生原因,并提出防止温度裂缝的技术措施。从而在施工过程中有效控制温度裂缝的产生。     

浅析现浇楼板裂缝产生原因及其主要治理措施

从现浇楼板裂缝产生部位入手,根据裂缝分布特征,分析了裂缝产生原因,并从设计、混凝土性能、施工方面总结了现浇楼板裂缝的治理措施,以减少楼板裂缝的产生,提高建筑物施工质量。     

大体积混凝土裂缝分析和防治

分析了混凝土施工裂缝产生的原因,从施工中的混凝土材料要求、混凝土浇捣与养护等方面进行了裂缝防治及处理措施的阐述,达到满足工程使用性和耐久性要求,从施工上避免了混凝土裂缝的产生。     

预拌泵送混凝土施工裂缝的分析和预防及处理

分析了预拌泵送混凝土施工裂缝所产生的原因,从施工中的预拌混凝土材料要求、混凝土浇捣与养护等方面进行了裂缝防治及处理措施的阐述,达到满足工程使用性和耐久性要求,从施工上避免了混凝土构件裂缝的产生。     

混凝土结构裂缝的分析与防治

从混凝土结构裂缝的现状、趋势及施工角度分析裂缝的产生原因,并提出预防出现裂缝的施工措施。     

浅议混凝土结构裂缝的原因及控制方法

就混凝土现浇板产生的裂缝问题，从温度变化、混凝土收缩、荷载、施工质量、冻胀几个方面分析了引起混凝土现浇板产生裂缝的原因，并从设计、施工、材料方面提出了裂缝的控制措施，以避免和减少裂缝的产生。     

浅析框架填充墙裂缝成因及防治措施

介绍了框架填充墙裂缝的主要形式和常出现部位,对框架填充墙体裂缝的产生原因进行了分析,从材料选择、设计、施工三方面阐述了控制填充墙裂缝产生的具体措施,以最大限度地减少裂缝的产生,从而保证施工质量。     

浅谈混凝土裂缝产生的原因及防治措施

从混凝土收缩裂缝、温度裂缝、后浇带施工不慎造成板面裂缝等方面分析了裂缝产生的原因,结合具体工程项目出现的裂缝,提出了混凝土裂缝产生的预防措施,以减少混凝土裂缝的产生。     

论现浇钢筋混凝土楼板裂缝的成因及预防

结合实际情况,主要从施工操作方面分析了现浇钢筋混凝土楼板裂缝产生的原因,并有针对性地提出了施工中的防治措施以及裂缝的处理方法,以减少混凝土楼板裂缝的产生。     

桥面铺装裂缝预防与对策

针对桥面铺装层产生的裂缝问题,从施工流程的角度,分析探讨了每道工序可能产生裂缝诸多因素,提出对策。目地为了预防施工后出现了裂缝,再采取各种补救措施,确保桥梁的设计施工质量。     

经济转轨背景下城市设计的演变历程和规律探讨

我国经济体制的转轨和建设机制的转型引发了城市设计的演变,促使城市设计在认识论层次上从思想理念向社会实践、从产品主导向过程主导演变,在方法论层次上从指令性控制向弹性引导、从“家长式”管理向制度化管理演变,在价值论层次上从粗放生产向有机生长、从技术工具向价值倡导演变。从总体上说,在经济转轨背景下,我国城市设计呈现从静态到动态、从工具理性到价值理性的演变规律。     

从线性到非线性：我国大学管理思维的延伸

随着科技发展与实践的深入,人们从追求简单性转向探索复杂性,科学思维方式由线性思维转向非线性思维。这启示我国大学管理思维要从封闭思维走向开放思维,从简单性思维走向复杂性思维,从确定性思雏走向随机性思雏。从经验性思维走向前瞻性思维。     

现代生态规划对传统城市规划的启迪

传统的城市规划至少可以从思想和方法两个方面,从现代生态规划中得到启迪。规划思想应从线性思维转向网络性整体思维,从人类中心论转向生态文明观,从以“为经济建设服务”转化为可持续发展。规划方法的启迪有:规划手段应由“硬”变“软”,规划依据应由“自上而下”变为“自下而上”,规划任务应由安排到引导,用地布局应由均质到异质。     

Detection of virulence genes in Escherichia coli of an existing metabolic fingerprint database to predict the sources of pathogenic E. coli in surface waters

A collection of 366 Escherichia coli strains from 10 host groups and surface waters were tested for the presence of 15 virulence genes associated with strains causing intestinal and extra-intestinal infections. The virulence genes included eaeA, VT1, 2 and 2e, LT1, ST1 and 2, Einv gene, EAgg gene, CNF1 and 2, papC, O111 and O157 side chain LPS. Of the 262 strains obtained from nine different hosts, 39 (15%) carried one or more of these virulence genes. These included six strains from humans, two from horses, eight from dogs, two from ducks, five from cattle, seven from chickens, four from pigs, two from sheep and three from deer. Of the remaining 104 strains obtained from water samples, 10 (10%) also carried one or more of the tested virulence genes. Of these, six had identical biochemical phenotypes (BPTs) to strains isolated from humans (two strains), dogs (two strains), chickens (one strain) and sheep (one strain) with 4 BPTs also carrying same virulence genes. Our results indicate that the sources of clinically important E. coli strains found in surface waters due to faecal contamination can be predicted by using a combination of biochemical fingerprinting method and the detection of virulence genes. From the public health point of view this information will be of great importance for evaluating the risk associated with public use of the catchment.     

Microbiological and chemical properties of litter from different chicken types and production systems

Chicken litter is produced in large quantities from all types of poultry raising activities. It is primarily used for land application, thus it is essential to analyze its properties before it is released to the environment. The objective of this study is to compare the microbiological and chemical properties of litter generated from layer and broiler chickens reared under intensive and free-range production systems. The microbiological analysis consisted of the enumeration of total bacteria, total coliforms, Staphylococcus species, Salmonella species and Clostridium perfringens. Chicken litter from layers reared under intensive and free range systems showed lower mean total bacterial count than the litter collected from chicken broilers reared under either of the two systems (P=0.0291). The litter from intensive layers had the lowest mean total coliform counts (P=0.0222) while the lowest Staphylococcus species count was observed in the litter from free-range layers (P=0.0077). The C. perfringens count was the lowest in chicken litter from intensively raised broilers and layers (P=0.0001). The chemical properties of litter from the different chicken types and production systems were compared based on determination of pH, electrical conductivity, carbon, nitrogen, phosphorus, potassium, cadmium and zinc. Litter from free-range broilers showed the highest pH value (P=0.0005); however, the electrical conductivity was higher in the litter from both intensive and free-range layers compared to the litter from both broiler production systems (P=0.0117). Chicken litter from intensive systems had higher nitrogen content than litter from free-range systems (P=0.0000). The total phosphorus was the lowest in free-range broiler litter (P=0.0001), while the total potassium was the lowest in litter from intensively managed broilers (P=0.0000). Zinc appeared higher in litter from layers compared to that from broilers (P=0.0101). The cadmium content was higher in the litter from free-range broilers and layers compared to that in the litter from intensively managed systems (P=0.0439). Staphylococcus species in the litter as well as cadmium concentrations seem to be the most critical parameters presenting risks on the environment and on human health. Based on the lowest coliform counts (an indication of water pollution), the high nutrient levels and the low cadmium values, litter from intensively managed layers appears as the most suitable for application on agricultural soils.     

地下建筑湿负荷计算

从地下建筑围护结构散湿、人体散湿、自由水面散湿、人为散湿、外部空气带湿五个方面介绍了地下建筑物内湿负荷的主要来源和计算方法。     

欧洲住房金融改革对中国的借鉴意义

自从1960与1970年代以来,更多的欧洲国家放松了它们的住宅政策。我们注意到从公共融资向私人融资的转变、从社会住宅向商业住宅的转变、从住房建设补贴向住房人头补贴的转变、从管制租金向市值租金的转变、以及从租赁房向自有房的转变。大部分这些转变都可以统称为＂私有化＂以及＂自由化＂这些定义不明的词语。然而,欧盟大部分国家的住宅金融体系仍然复杂而不合理,需要更多的住宅金融改革。我们将详述一种住宅金融改革的核心内容,包括如下几点：住房建设补贴、租户的住房人头补贴、自有房的税收优惠、房屋租赁政策、以及住宅联盟的角色。通过这种分析,我们勾画出欧盟国家住宅金融深入改革的轮廓。在不久的将来,中国也会考虑相似的住宅金融改革。     

上海地区城市化过程中的文化复兴

针对上海地区文化复兴这一现象，利用以人为本的理念，着眼于整体的方法，运用系统理论，建立了从认识到方法，从分析到设计，全方位地开敞框架系统。     

Trace element carriers in combined sewer during dry and wet weather: an electron microscope investigation

The nature of trace element carriers contained in sewage and combined sewer overflow (CSO) was investigated by TEM-EDX-Electron diffraction and SEM-EDX. During dry weather, chalcophile elements were found to accumulate in sewer sediments as early diagenetic sulfide phases. The sulfurization of some metal alloys was also evidenced. Other heavy metal carriers detected in sewage include metal alloys, some iron oxihydroxide phases and neoformed phosphate minerals such as anapaite. During rain events, the detailed characterization of individual mineral species allowed to differentiate the contributions from various specific sources. Metal plating particles, barite from automobile brake, or rare earth oxides from catalytic exhaust pipes, originate from road runoff, whereas PbSn alloys and lead carbonates are attributed to zinc-works from roofs and paint from building siding. Soil contribution can be traced by the presence of clay minerals, iron oxihydroxides, zircons and rare earth phosphates. However, the most abundant heavy metal carriers in CSO samples were the sulfide particles eroded from sewer sediments. The evolution of relative abundances of trace element carriers during a single storm event, suggests that the pollution due to the "first flush" effect principally results from the sewer stock of sulfides and previously deposited metal alloys, rather than from urban surface runoff.     

Sources and properties of non-exhaust particulate matter from road traffic: a review

While emissions control regulation has led to a substantial reduction in exhaust emissions from road traffic, currently non-exhaust emissions from road vehicles are unabated. These include particles from brake wear, tyre wear, road surface abrasion and resuspension in the wake of passing traffic. Quantification of the magnitude of such emissions is problematic both in the laboratory and the field and the latter depends heavily upon a knowledge of the physical and chemical properties of non-exhaust particles. This review looks at each source in turn, reviewing the available information on the source materials and particles derived from them in laboratory studies. In a final section, some of the key publications dealing with measurements in road tunnels and the roadside environment are reviewed. It is concluded that with the exception of brake dust particles which may be identified from their copper (Cu) and antimony (Sb) content, unequivocal identification of particles from other sources is likely to prove extremely difficult, either because of the lack of suitable tracer elements or compounds, or because of the interactions between sources prior to the emission process. Even in the case of brake dust, problems will arise in distinguishing directly emitted particles from those arising from resuspension of deposited brake dust from the road surface, or that derived from entrainment of polluted roadside soils, either directly or as a component of road surface dust.