深厚黄土覆盖层上土石坝地震响应特性分析

采用非线性有限单元法和笔者曾提出的动孔压试验曲线法,对某深厚黄土覆盖层上土石坝进行了有效应力法地震响应分析,重点分析大坝的绝对加速度、动位移和动应力等动力响应及动孔隙水压力分布情况。分析结果表明,在现有设计条件下,由于坝基软弱黄土覆盖层较厚,大坝在7度地震作用下地震响应不强烈,但坝基黄土覆盖层会出现液化情况,需采取相应的抗液化工程措施。     

Changes in the upper limits of tree species distribution in the Western Caucasus (Belaya River basin) related to recent climate warming

To estimate the response of tree vegetation to recent climate warming in the Western Caucasus, the population state of several tree species at the upper limit of their distribution has been estimated in three mountain massifs in the Belaya River basin. For this purpose, the average and maximum stem diameters, vitality, and age of trees have been determined in the transitional zone between middle-mountain and high-mountain beech-fir forests (1400–1700 m a.s.l.) and in crooked birch forests growing at the upper timberline (1810–2025 m). The upper limits of Acer platanoides, A. pseudoplatanus, Ulmus glabra, and Betula litwinowii have shown a tendency to rise. The upper limit of Abies nordmanniana has remained unchanged over the past few decades, which may be explained by a decrease in moisture supply during the warm season.     

电焊熔珠对棉布和聚氨酯泡沫的引燃能力研究

研究了加载电压对电焊熔珠数目和粒径分布的影响,在模拟装置上实验了电焊对棉布、聚氨酯泡沫和纸张的引燃性能.结果表明,随着加载电压升高,电焊熔珠的数目逐渐减少,熔珠粒径逐渐增大,引燃能力逐渐增强.固体材料性质对电焊熔珠引燃能力也有很大影响,表面粗糙,易蓄热材料容易被点燃.电焊熔珠引燃棉布、聚氨酯泡沫和纸张的临界电压为37.5V、40V和45V.     

Di（2-ethylhexyl）phosphoric acid-coconut oil supported liquid membrane for the separation of copper ions from copper plating wastewater

Permeation of Cu(II) from its aqueous solution through a supported liquid membrane (SLM) containing di(2-ethylhexyl)phosphoric acid (D2EHPA) carrier dissolved in coconut oil has been studied. The effects of Cu(II), pH (in feed), H2SO4 (stripping) and D2EHPA (in membrane) concentrations have been investigated. The stability of the D2EHPA-coconutoil has also been evaluated. High Cu(II) concentration in the feed leads to an increase in flux from 4.1 × 10-9 to 8.9 × 10-9 mol/(m2·s) within the Cu(II) concentration range 7.8×10-4-78.6×10-4 mol/L at pH of 4.0 in the feed and 12.4 × 10-4 mol/L D2EHPA in the membrane phase. Increase in H2SO4 concentration in strip solution leads to an increase in copper ions flux up to 0.25 mol/L H2SO4, providing a maximum flux of 7.4 × 10-9 mol/(m2·s). The optimum conditions for Cu(II) transport are, pH of feed 4.0, 0.25 mol/L H2SO4 in strip phase and 12.4 × 10-4 mol/L D2EHPA (membrane) in 0.5 (m pore size polytetrafluoroethylene (PTFE) membrane. It has been observed that Cu(II) flux across the membrane tends to increase with the concentration of copper ions. Application of the method developed to copper plating bath rinse solutions has been found to be successful in the recovery of Cu(II). rane. It     

Determination of granule size distribution in a UASB reactor

Granular sludge is the key factor for an efficient operation of an upflow anaerobic sludge blanket (UASB) reactor. In order to monitor the granularity of anaerobic sludge, the determination of the granule size distribution is of vital importance. For this reason, several techniques have been proposed; however, they are either tedious, imprecise or expensive and hardly applicable in full-scale treatment plants. There was then the need for a simple and low-cost technique. This technique involves the determination of the settling velocities of a sludge sample and of extrapolating the corresponding diameters using a mathematical algorithm. In the proposed algorithm, the granules density was calculated, the flow regime was examined and finally the granule size distribution was obtained. Two very important correlations were suggested by the experimental results. The granule density and diameter were strongly correlated with the VSS/TSS ratio.     

SBR池射流曝气水射器喷头的改制、安装与调试

在工程调试中发现了问题 ,根据现场的实际情况 ,将射流器作了改制 ,并改变安装方法 ,最终达到预期效果     

Spatially Disaggregated Inventories of Soil NO and N2O Emissions for Great Britain

Estimates of soil N₂O and NOemissions at regional and country scales arehighly uncertain, because the most widely usedmethodologies are based on few data, they do notinclude all sources and do not account forspatial and seasonal variability. To improveunderstanding of the spatial distribution of soilNO and N₂O emissions we have developedsimple multi-linear regression models based onpublished field studies from temperate climates.The models were applied to create spatialinventories at the 5 km² scale of soil NOand N₂O emissions for Great Britain. The N₂O regression model described soilN₂O emissions as a function of soil N input,soil water content, soil temperature and land useand provided an annual N₂O emission of 128 kt N₂O-N yr^-1. Emission rates largerthan 12 kg N₂O-N ha^-1 yr^-1 werecalculated for the high rainfall grassland areasin the west of Great Britain.Soil NO emissions were calculated using tworegression models, which described NO emissionsas a function of soil N input with and without afunction for the water filled pore space. Thetotal annual emissions from both methods, 66 and7 kt NO-N yr^-1, respectively, span the rangeof previous estimates for Great Britain.     

Mobilization of heavy metals from contaminated paddy soil by EDDS,EDTA, and elemental sulfur

For enhanced phytoextraction, mobilization of heavy metals (HMs) from the soil solid phase to soil pore water is an important process. A pot incubation experiment mimicking field conditions was conducted to investigate the performance of three soil additives in mobilizing HMs from contaminated paddy soil (Gleyi-Stagnic Anthrosol): the [S, S]-isomer of ethylenediamine disuccinate (EDDS) with application rates of 2.3, 4.3, and 11.8 mmol kg⁻¹ of soil, ethylenediamine tetraacetate (EDTA; 1.4, 3.8, and 7.5 mmol kg⁻¹), and elemental sulfur (100, 200, and 400 mmol kg⁻¹). Temporal changes in soil pore water HM and dissolved organic carbon concentrations and pH were monitored for a period of 119 days. EDDS was the most effective additive in mobilizing soil Cu. However, EDDS was only effective during the first 24 to 52 days, and was readily biodegraded with a half-life of 4.1 to 8.7 days. The effectiveness of EDDS decreased at the highest application rate, most probably as a result of depletion of the readily desorbable Cu pool in soil. EDTA increased the concentrations of Cu, Pb, Zn, and Cd in the soil pore water, and remained effective during the whole incubation period due to its persistence. The highest rate of sulfur application led to a decrease in pH to around 4. This increased the pore water HM concentrations, especially those of Zn and Cd. Concentrations of HMs in the soil pore water can be regulated to a large extent by choosing the proper application rate of EDDS, EDTA, or sulfur. Hence, a preliminary work such as our pot experiment in combination with further plant experiments (not included in this study) will provide a good tool to evaluate the applicability of different soil additives for enhanced phytoextraction of a specific soil.     

长江重庆段两江水相、间隙水和沉积物中邻苯二甲酸酯的分布与分配

对长江重庆段两江水相、间隙水和沉积相中5种邻苯二甲酸酯(PAEs)的分布与分配进行了研究.结果显示水相中PAEs含量为53.2 ～343.0 ng·L-1,间隙水中为916.8～7517.1 ng·L-1,沉积相为1787.0 ～5045.9 ng·g-1,间隙水相PAEs含量高于水相;比较两江PAEs分布,支流嘉陵江污染程度高于长江干流;邻苯二甲酸二丁酯(DBP)和邻苯二甲酸双(2-乙基己基)酯(DEHP)是水体和沉积物中的主要污染物,在间隙水相存在明显富集,这两种污染物在水相中的含量低于地表水质量标准;黏土是影响沉积相中PAEs分布的重要因素,有机质含量对其影响较小;沉积物-间隙水间的lgKoc值与lgKow不相关,DBP在沉积物和间隙水间的分配接近平衡,邻苯二甲酸二甲酯(DMP)、邻苯二甲酸二乙酯(DEP)有由沉积相向间隙水相迁移的趋势,DEHP则由间隙水相向沉积相迁移.与国内外其他地区相比,研究区PAEs含量处于中等偏下水平.