深层水泥搅拌桩施工质量监控

深层水泥搅拌桩是进行软基处理的一种有效形式，现在在沿海地区软基处理中已被广泛应用。但因水泥搅拌桩属隐蔽工程，工序环节多，施工控制难度大．因此，严格对施工过程的控制非常重要。本文通过对泉州市笋江路、池峰路水泥搅拌桩施工实践，对水泥搅拌桩施工质量监控作了较为全面的阐述。     

水泥搅拌桩现场施工技术及管理控制

针对水泥搅拌桩在工程中的广泛应用,论述了水泥搅拌桩施工前的准备工作,详细地介绍了水泥搅拌桩的现场施工技术,就施工中如何做好水泥管理及人员管理工作进行了探讨,从而保证水泥搅拌桩的工程质量。     

水泥搅拌桩在水利工程中的应用

结合工程实例，介绍了水泥搅拌桩的加固机理，对水泥搅拌桩的设计、施工及施工质量控制措施进行了论述，并对水泥搅拌桩的施工质量进行了检测分析，提出了一些建议。     

水泥搅拌桩施工技术在公路软土路基中的应用

基于水泥搅拌桩的施工原理、特点和作用,阐述了水泥搅拌桩的施工准备及工艺流程,并总结了施工中常见问题的处理措施,旨在保证水泥搅拌桩的施工质量。     

水泥搅拌桩加固软土地基施工技术

本文以水泥搅拌桩加固软土地基的工程实例，阐述了水泥搅拌桩的施工工艺、施工技术、及施工过程中需注意的问题。     

深层水泥搅拌桩在软粘土地基加固中的应用

介绍了水泥搅拌桩进行地基处理的设计要求，根据水泥搅拌桩的施工工艺流程，论述了施工关键环节，总结了施工质量控制措施，并对其处理效果作了检验，结果表明深层搅拌桩的地基处理是可行的。     

市政工程中水泥搅拌桩技术的应用要点

文章首先阐述了水泥搅拌桩技术的作用原理,其次分析了水泥搅拌桩技术在市政工程中应用的优势和不足,最后说明了水泥搅拌桩技术在市政工程施工中的应用要点,包括做好施工前的准备工作、水泥搅拌桩技术的具体施工工艺。     

水泥搅拌桩在软土路基处理中的应用

分析了水泥搅拌桩加固软土地基的原理,另外结合经验论述了水泥搅拌桩施工控制以及选用水泥搅拌桩应注意的问题,最后浅析了水泥搅拌桩施工质量检验,实践证明,水泥搅拌桩处理软土路基是一种行之有效的方法。     

水泥搅拌桩处理软基施工中的监理质量对策

水泥搅拌桩处理软土地基是一在种安全可靠,经济效益高的施工方法,在建筑领域施工中承担着重要的角色,与地基土共同发挥着至关重要的作用。本文正是从水泥搅拌桩软土地基施工上的应用着手,简要介绍了水泥搅拌桩的形成机理,简单分析了水泥搅拌桩在软土地基施工中出现的相关问题,并根据这些具体的问题,阐述了在软土地基施工过程中如何监控水泥搅拌桩的质量问题,如何通过这些高效科学的监控对策保证水泥搅拌桩在处理软土地基上的加固效果。     

深层水泥搅拌桩在施工中的应用

介绍了水泥搅拌桩的特点，通过分析影响水泥搅拌桩强度的主要因素，提出了深层水泥土搅拌桩的施工工艺措施及施工注意事项，经拖工后沉降观测，指出深层水泥搅拌桩处理软土地基沉降量很小，效果显著。     

The contribution of polyphenols to plant resistance to Pb soil pollution

This article considers the concentration of lead, polyphenols and water-soluble antioxidants (AOA) in the leaves of 4 species of woody, 11 species of shrub and 7 species of herbaceous plants growing in different functional zones in the city of Kaliningrad. The accumulations of Pb – the principal pollutant in urban ecosystems – were studied in the urban topsoil and plant leaves. An increase in Pb concentration in soils was associated with a decrease in AOA in tissues of the species examined. Changes in the background concentrations of antioxidants make it possible to estimate plant resistance to environmental stresses. The authors examine the contribution of polyphenols to the antioxidant potential of urban plants in soil polluted by Pb. The results obtained can be used to determine urban plant resistance to human impact and to improve the monitoring of industrial pollution in urban areas.     

The effects of changing water flow velocity on the formation of biofilms and water quality in pilot distribution system consisting of copper or polyethylene pipes

We studied the effects of flow velocity on the formation of biofilms and the concentration of bacteria in water in copper and plastic (polyethylene, PE) pipes. The formation of biofilms increased with the flow velocity of water. The increase in microbial numbers and contents of ATP was clearer in the PE pipes than in the copper pipes. This was also seen as increased consumption of microbial nutrients in the pipeline system. This indicates that the mass transfer of nutrients is in major role in the growth of biofilms. However, the increased biomass of biofilms did not affect microbial numbers in the water. Rapid changes in water flow rate resuspended biofilms and sediments which increased the concentrations of bacteria and copper in water. The disturbance caused by the changing water flow was also seen as an increase in the particle counts and water turbidity recorded with online instrumentation.     

Ecological succession in mountain lake ecosystems of Southern Siberia after the introduction of the peled – Coregonus peled (Gmeli, 1778)

Abstract

This article summarizes a long-standing study of the process of introduction of the peled to the Southern Siberian mountain lake ecosystems. The peled has adapted to changes in food supply. Pressure of the euryphagous peled caused the substitution of larger forms of zooplankton by smaller ones. Similar changes occurred in the content of phytoplankton. Succession of zoobenthos in the littoral part of the lakes manifested itself as the decrease in the total biomass, in its part of zoobenthos (Gammarus) and as the increase in the biomass of other groups. The opposite changes were encountered in the profundal zone of zoobenthos (the decrease in the total biomass owing to the existence of larger forms of alpha-polysaprobes). The restructuring observed in various communities signifies the substantial changes in the whole process of generation and transformation of organic substance in the mountain ecosystems with the dominance of the introduced peled.     

Heterotrophic and mixotrophic growth of Micractinium pusillum Fresenius in the presence of acetate and glucose: effect of light and acetate gradient concentration

The main objective of this study was to determine the importance of secondary mechanism of organic carbon utilization (mixotrophic and heterotrophic modes) in addition to CO2 fixation (photoautotrophic mode) in the green alga, Micractinium pusillum Fresenius (chlorophyta), isolated from a waste stabilization pond. The growth was studied in the presence of acetate and glucose. The incorporation rate of 14C- acetate was measured in the light and in the dark at different concentrations. Finally, in order to underline the role of photosynthesis and respiration processes in the acetate assimilation, the effect of two specific metabolic inhibitors, a specific inhibitor of photosystem II (DCMU) and an uncoupler respiratory (DNP), has been studied. The obtained results showed that M. pusillum grows in the presence of organic substrates, i.e., glucose and acetate, in the light (mixotrophic growth) as well as in the dark (Heterotrophic growth). The growth was much more important in the light than in the dark and more in the presence of glucose than of acetate. In the light, the presence of acetate led to a variation of growth parameters mumax, iotaopt, and beta. The effect of acetate gradient on the growth of the microalga was severe as soon as its concentration in the medium was higher. The acetate uptake followed a Michaelis-Menten kinetic in the light as well as in the dark. The capacity of assimilation was slightly higher in the dark. The utilization of DNP and DCMU indicates that acetate incorporation is an active process depending on both anabolic (photosynthesis) and catabolic (respiration) metabolisms, corroborating the model of the Michaelis-Menten kinetic.     

Alteration of arsenopyrite in soils under different vegetation covers

The weathering of arsenopyrite (FeAsS) has been monitored in soils using an in situ experimental approach. Arsenopyrite in nylon experimental bags was placed in individual horizons in soils in spruce (litter, horizons A, B, and C), beech (litter, horizons A, B, and C) and unforested (horizons A, B, and C) areas and left in contact with the soil for a period of 1 year. The individual areas on the ridge of the Krušné hory Mts., Czech Republic, had the same lithology, climatic and environmental conditions. Scorodite (FeAsO₄·2H₂O) was identified as a principal secondary mineral of arsenic (As) formed directly on the surface of the arsenopyrite. Scorodite was formed in all the areas in all soil horizons. The amount of scorodite formed decreased in the series beech, spruce and unforested areas. In forested areas, there was a larger amount of scorodite on arsenopyrites exposed in organic horizons (litter, A horizon). The greater rate of arsenopyrite alteration in organic horizons in the beech stand compared to spruce stand is probably a result of faster mineralization of organic material with resulting production of nitrate and better seepage conditions of soil in this area. Speciation of As determined using the sequential extraction technique demonstrated that As was bonded in the soils primarily in the residual fractions prior to the experiment. The As content in the mobile fractions increased in the organic horizon in the forested areas after the experiments.     

不同介质中MOV小电流特性的对比研究

氧化锌电阻片(MOV)常用于过电压保护,其小电流特性决定了它的工频稳定性。随着电力技术的发展,MOV被应用于变压器绕组内部和超导电力系统中,MOV的工作介质为变压器油和液氮。将MOV在空气和变压器油、空气和液氮(77K)中分别进行对比试验,通过小波变换对原始数据进行去噪,利用各次谐波法提取阻性电流进行对比分析,结果显示:MOV在变压器油中的阻性电流峰值大于空气中的值,MOV在液氮中的晶界电容、阻性电流峰值均小于空气中的值。表明MOV的小电流特性在空气中优于变压器油中,在液氮温区优于常温下。     

在革新与现代主义之间:夏昌世与德国(英文)

夏昌世,中国第一代建筑师,1920年代在德国卡尔斯鲁厄留学。1932年,他在图宾根完成了博士论文之后重返祖国。1940年代后期,他在广州成为教授,1973年与妻子一同重返德国,并在那里生活直至1996年逝世。他的设计方法不仅受到那个时代欧洲现代主义运动氛围的熏陶,还来自他对中国传统景观与建筑艺术历史的研究。他是引领岭南区域形成岭南学派建筑的主导力量之一。同时,作为一建筑学教授,他在广州培养了新一代青年建筑师。     

Use of iodide to enhance the phytoextraction of mercury-contaminated soil

Low bioavailability of mercury (Hg) in soil is a restricting factor in phytoextraction of Hg-contaminated soil. Iodide is known to mobilize Hg in soil and, therefore, the aim of this study was to investigate the possibility to use iodide to increase phytoextraction of Hg. The sensitivity of willow to iodide was investigated in both hydroponics with 0-10 mM KI and in soil with 0.2 and 1 mM KI addition. The capacity to accumulate HgI(2) was compared with that of Hg(NO(3))(2) in hydroponics. Soil extractions with 0-2 mM KI were used to study mobilization of Hg in aged Hg-spiked soil. Additions of KI (0.2-1 mM) were used in pot tests with aged Hg-spiked soil as well as in field trials in an industrial Hg-contaminated soil to study whether iodide addition increased the accumulation of Hg from contaminated soil and the translocation of Hg to the shoots. The total Hg contents in plants, soils and extracts were analyzed by CVAAS. The results showed that too high KI concentration was toxic to plants. Moreover, KI was toxic to plants at lower concentrations in hydroponics than in soil additions. KI (85 microM) in hydroponics gave 50% growth decrease in terms of dry weight of shoot biomass, whereas 0.2 mM KI in soil addition could be tolerated by the plant without growth disturbance. Willow accumulated Hg from HgI(2) solution slower than that from Hg(NO(3))(2) solution. KI mobilized Hg in contaminated soil and thereby increased the bioavailability of Hg in soil. Up to 1 mM KI addition increased the Hg concentrations to about 5, 3 and 8 times, respectively, in the leaves, branches and roots. However, the Hg translocation to the shoots did not show an increase with KI addition. Only less than 1% of the total Hg accumulated in the plant was distributed in the shoots. We may conclude that iodide addition enhances the phytoextraction of Hg, however, the translocation of Hg to the shoots is still too low and therefore it will not be realistic to use this method for phytoextraction of Hg-contaminated soil in practice.     

Health assessment of artisanal gold miners in Indonesia

Small scale miners use mercury to extract gold from ore in many countries. An environmental and health assessment was performed in Indonesia in two regions, Galangan in Central Kalimantan and Talawaan in Northern Sulawesi. The environmental assessment showed severe mercury contamination of the sediments, and increased mercury levels in local fish. For the health investigation 281 volunteers were recruited and examined by a standardized questionnaire, a neurological examination and neuro-psychological tests. A medical score was used consisting of significant factors of mercury intoxication. Mercury exposed workers showed typical symptoms of mercury intoxication, such as movement disorders (ataxia, tremor, dysdiadochokinesia, etc.). Blood, urine and hair samples were taken from any participant and analyzed for mercury. The mercury concentration in the biomonitors was high, partly extreme high in the working population, increased in the population living in the same habitat and low in the control group. By a standard protocol which includes a combination of threshold values of mercury in the biomonitors and a medical sum score the diagnosis of chronic mercury intoxication was made for highly burdened workers (amalgam smelters) in 55% in Sulawesi and in 62% in Kalimantan. Less exposed mineral processors and the general population in the mining areas were also intoxicated to a high percentage.     

Polycyclic aromatic hydrocarbons (PAHs) in agricultural soil and vegetables from Tianjin

Several types of vegetables were collected from two contaminated sites in Tianjin, China. The bulk soil and the rhizosphere soil samples were also collected from the same plots. Sixteen PAHs in the samples were measured. The total concentrations of PAH16 in the bulk soil from the two sites were 1.08 and 6.25 microg/g, respectively, with similar pattern. The concentrations of PAH16 and individual compounds in the rhizosphere were significantly higher than those in the bulk soil with mean values of 2.25 and 7.82 microg/g for the two sites, respectively. The contents of both total and dissolved organic matter in the rhizosphere were also higher than those in the bulk soil. Almost all PAH compounds studied were detected in both roots and aerial parts of the vegetables studied. Abundance of higher molecular weight PAHs in vegetable, however, was lower than that in soil. Concentrations of PAH16 in vegetable were higher than those reported in the literature for other areas. It appears that agricultural soils and vegetables in Tianjin, especially those from the site located immediately next to an urban district and irrigated with wastewater for several decades, are severely contaminated by PAHs. Among the eight types of vegetable studied, the highest concentration of PAHs was found in cauliflower. By average, the concentration of PAH16 in the aerial part of vegetables was 6.5 times higher as that in vegetable root, suggesting that foliar uptake is the primary transfer pathway of PAHs from environment to vegetables.