磷酸铵镁技术中不同沉淀剂脱氮除磷效果比较

探讨了磷酸铵镁法中不同沉淀剂的脱氮除磷效果,比较了氨氮去除率、磷酸盐去除率、残氮量、残磷量,沉淀物质质量和组成,处理液的电导率。综合考虑了各方面因素得出处理高浓度氨氮废水的较佳的沉淀剂为Na3PO.412H2O MgCl2.6H2O和Na3PO4.12H2O MgSO4.7H2O,处理高浓度磷酸盐废水的较佳的沉淀剂为NH4Cl MgCl2.6H2O和NH4Cl MgSO.47H2O.并对磷酸铵镁沉淀进行了X-衍射光谱和扫描电镜表征。     

地铁车站深基坑降水设计与实施效果分析

根据降水基本原理,针对工程水文地质情况,选取合理可靠的计算参数,通过理论计算并参考已有的经验数据,确定降水设计方案;结合具体工程项目组织实施,通过分析实施效果验证方案的有效性。     

富水软土地区深基坑降水施工技术

针对富水软土地质深基坑开挖,为确保安全,通过抽水试验,分析确定降水参数,在保证降水效果的前提下,减少降水井,方便了后续施工,节省了工程费用,提高了经济效益。     

潜水含水层非稳定井流降水的有限差分分析

滨海地区利用吹填淤泥或砂围海造陆将在地基上部形成一潜水含水层,但现有方法大都依赖于Theis非稳定承压含水层井流理论求解水文地质参数,进行降水设计,缺乏合理性。结合广州港南沙港区粮食及通用码头软基试验区科研项目,利用Neuman非稳定井流理论进行潜水含水层水文地质求参,将所得参数进行有限差分分析,数值结果与水位监测成果一致。工程实例表明,该方法合理、可靠,为类似应用提供了一种新途径。     

基于微生物诱导碳酸钙沉积(MICP)改善淤泥质土强度

采用微生物诱导碳酸钙沉积(MICP)对淤泥质土进行处理,用于提高淤泥质土的强度。以武汉东湖淤泥为研究对象,对MICP改性淤泥质土进行快剪试验与固结快剪试验。试验结果表明:MICP改性淤泥质土能增大淤泥质土的内摩擦角,对其黏聚力改变较小;MICP改性淤泥质土,胶结液浓度在1mol/L时对土体内摩擦角提高效果最好,快剪试验中MICP改性淤泥质土的内摩擦角从素土的8.54°提升至23.18°,提升了171.4%;固结快剪试验中MICP改性淤泥质土的摩擦角从15.96°提升至25.36°,提升了58.9%;MICP改性淤泥质土,生成碳酸盐沉积把土体小颗粒胶结成大颗粒,提高了土体大颗粒的质量分数。     

沙漠地区涵洞轻型井点降水施工技术

S313线兰嘎段LJ-11标位于内蒙占南部毛乌素沙漠腹地.地层为粉细砂.为完成涵洞基坑开挖任务.经方案比选采取轻型井点降水措施.主要介绍轻型井点降水的施工设计、井点管安设、降水、施工注意事项等内容,并分析了影响降水的各种因素.提出了改进降水效果的有效途径和措施,对类似工程有借鉴意义.     

松花江斜拉桥主塔承台井点降水的设计与施工

介绍了哈尔滨绕城高速公路西段松花江大桥主塔承台井点降水施工方案设计及实施情况 ,对于类似桥梁基础施工有一定的参考价值     

Coupled transport-reaction pathways and distribution patterns between siliciclastic-carbonate sediments at the Ria de Vigo

This paper examines the linkages between the space-distribution of grain sizes and the relative percentage of the amount of mineral species that result from the mixing process of siliciclastic and carbonate sediments at the Ria de Vigo (NW of Spain).The space-distribution of minerals was initially determined, starting from a detailed mineralogical study based on XRD-Rietveld analysis of the superficial sediments. Correlations between the maps obtained for grain sizes, average fractions of either siliciclastic or carbonates, as well as for individual-minerals, were further stabilised. From this analysis, spatially organized patterns were found between carbonates and several minerals involved in the siliciclastic fraction. In particular, a coupled behaviour is observed between plagioclases and carbonates, in terms of their relative percentage amounts and the grain size distribution.In order to explain these results a conceptual model is proposed, based on the interplay between chemical processes at the seawater–sediment interface and hydrodynamical factors. This model suggests the existence of chemical control mechanisms that, by selective processes of dissolution-crystallization, constrain the mixed environment's long-term evolution, inducing the formation of self-organized sedimentary patterns.     

On the fresh balance of the Adriatic Sea

The long-term mean fresh water balance of the Adriatic Sea is studied by ananalysing evaporation, precipitation and river runoff. Evaporation is computed from May latent heat flux and by means of bulk formula. In the latter case two wind speed data sets are used, namely those from the NMC and May. The sea surface temperature is taken from a historical Adriatic data set, and the air temperature and relative humidity come from the NMC data set. Two precipitation data sets are considered, namely the Legates and Willmott climatology and a data set consisting of data measured at 62 rain-gauge stations located on the Adriatic coasts. Runoff contribution to the fresh water balance is estimated from the long-term average flow rates of 39 rivers and the horizontal distribution of salinity in the upper mixed layer.The spatial distribution of the fresh water balance, as well as of its components, is analysed by means of monthly objective maps, from which averages and standard deviations are computed. The results obtained from the different computations are not always univocal, particularly in the evaluation of Summer evaporation, and are affected by relatively large statistical errors. Significant spatial and seasonal variability occurs, with a noticeable fresh water gain along the coastline of the northern and middle basins, while small areas of fresh water loss are found in the middle and southern basins. Nevertheless, on an annual basis, the difference between the fresh water losses by evaporation and the gains by precipitation and runoff is clearly negative, indicating that, unlike the whole Mediterranean, the Adriatic Sea is generally a dilution basin.     

Fe—Mo合金的时效析出行为

用 X 射线、电子衍射及透射电镜观察等方法研究了 Fe-27Mo 及 Fe-16Mo 合金的时效析出行为.结果发现,在873～1453K 时效时.时效初期,两种合金中均有一种新的过渡相——R 相析出.随时效进行,过渡相 R 将向平衡相μ(1213～1453K)或 Laves(873～1213K)转度.过渡相 R 为菱形点阵,点阵常数α=0.8977nm,α=74.4°,其 Mo 含量为48%,呈棒状或块状形态析出.时效初期由于过渡相 R 的析出引起合金硬化.