SAS/IPPA/AA三元共聚物对碳酸钙阻垢性能的研究

以水为溶剂,过硫酸铵为引发剂,丙烯磺酸钠、异丙烯膦酸和丙烯酸为单体,合成了三元共聚物丙烯磺酸钠/异丙烯膦酸/丙烯酸(SAS/ IPPA/AA),研究了共聚物在不同水质条件下对CaCO3的阻垢性能,探讨了共聚物浓度、pH值、钙离子浓度、碳酸根离子浓度和温度等条件对CaCO3的阻垢性能的影响,结果显示,在共聚物用量为18mg·l-1时,可使阻垢率达到100%.     

山西省稷山和永济两地矮牡丹体内无机元素含量的比较

采用原子吸收分光光度法和比色法测定了山西省稷山和永济两地区矮牡丹体内和生境土壤中的10种元素(K、Mg、Mn、Fe、Ni、Zn、Cu、Cd、Cr、Pb),分析比较了各种元素在不同地区矮牡丹体内和生境土壤中的分布规律及不同地区矮牡丹对无机元素的吸收富集能力.结果表明,两地区矮牡丹体内和生境土壤中无机元素含量无显著性差异;土壤及植株不同器官间元素含量也无显著性差异;两地区矮牡丹对不同元素的富集系数有显著差异,差异主要表现在对Cd(永济0.457,稷山0.213)和Ni(永济0.093,稷山0.167)的富集上,植株不同器官之间的富集系数无显著差异.表4参9     

Quantifying the efficiency of soil sampling designs: A multivariate approach

The objective of this paper is to quantify and compare the loss functions of the standard two-stage design and its composite sample alternative in the context of multivariate soil sampling. The loss function is defined (conceptually) as the ratio of cost over information and measures design inefficiency. The efficiency of the design is the reciprocal of the loss function. The focus of this paper is twofold: (a) we define a measure of multivariate information using the Kullback–Leibler distance, and (b) we derive the variance-covariance structure for two soil sampling designs: a standard two-stage design and its composite sample counterpart. Randomness in the mass of soil samples is taken into account in both designs. A pilot study in Slovenia is used to demonstrate the calculations of the loss function and to compare the efficiency of the two designs. The results show that the composite sample design is more efficient than the two-stage design. The efficiency ratio is 1.3 for pH, 2.0 for C, 2.1 for N, and 2.5 for CEC. The multivariate efficiency ratio is 2.3. These ratios primarily reflect cost ratios; influence of the information is small.     

Is there a relationship between soil and groundwater toxicity?

Part IIA of the Environmental Protection Act 1990 requires environmental regulators to assess the risk of contaminants leaching from soils into groundwater (DETR, 1999). This newly introduced legislation assumes a link between soil and groundwater chemistry, in which rainwater leaches contaminants from soil into the saturated zone. As the toxicity of both groundwater and overlying soils is dependent upon the chemicals present, their partitioning and their bioavailability, similar patterns of soil, leachates and groundwater toxicity should be observed at contaminated sites. Soil and groundwater samples were collected from different contaminated land sites in an urban area, and used to determine relationships between soil chemistry and toxicity, mobility of contaminants, and groundwater chemistry and toxicity. Soils were leached using water to mimic rainfall, and both the soils and leachates tested using bioassays. Soil bioassays were carried out using Eisenia fetida, whilst groundwater and leachates were tested using the Microtox test system and Daphnia magna 48 h acute tests. Analysis of the bioassay responses demonstrated that a number of the samples were toxic to test organisms, however, there were no significant statistical relationships between soil, groundwater and leachate toxicity. Nor were there significant correlations between soil, leachates and groundwater chemistry.     

The effect of diesel fuel on common vetch (Vicia sativa L.) plants

When petroleum hydrocarbons contaminate soil, the carbon:nitrogen (C:N) ratio of the soil is altered. The added carbon stimulates microbial numbers but causes an imbalance in the C:N ratio which may result in immobilization of soil nitrogen by the microbial biomass, leaving none available for plant growth. As members of Leguminosae fix atmospheric nitrogen to produce their own nitrogen for growth, they may prove more successful at growing on petroleum hydrocarbon contaminated sites. During a wider study on phytoremediation of diesel fuel contaminated soil, particular attention was given to the performance of legumes versus other plant species. During harvesting of pot experiments containing leguminous plants, a recurring difference in the number and formation of root nodules present on control and contaminated Common vetch (Vicia sativa L.) plants was observed. The total number of nodules per plant was significantly reduced in contaminated plants compared to control plants but nodules on contaminated plants were more developed than corresponding nodules on control plants. Plant performance of Common vetch and Westerwold's ryegrass (Lolium multiflorum L.) was compared to illustrate any difference between the ability of legumes and grasses to grow on diesel fuel contaminated soil. Common vetch was less affected by diesel fuel and performed better in low levels of diesel fuel contaminated soil than Westerwolds ryegrass. The total amount of diesel fuel remaining after 4 months in Common vetch planted soil was slightly less than in Westerwolds ryegrass planted soil.     

光(温)敏核不育水稻生态及生理生化研究概述

本文介绍了光、温敏核不育水稻在生态及生理生化方面取得的主要成就.着重概述了光、温敏核不育水稻雄性育性转换的光温生态条件,育性转换过程中蛋白质、氨基酸、酶活性、ATP及内源植物激素持续变化.另外,对光、温敏不育水稻研究存在的问题进行了分析.     

Dynamics of Turbulence in Low-Speed Oscillating Bottom-Boundary Layers of Stratified Basins

This paper focuses on the impact of an oscillating low-speed current on the structure and dynamics of the bottom-boundary layer (BBL) in a small stratified basin. A set of high-resolution current profile measurements in combination with temperature-microstructure measurements were collected during a complete cycle of the internal oscillation (`seiching') in the BBL of Lake Alpnach, Switzerland. It was found that even a relatively long seiching period of 24 hours significantly changed the form of the near-bottom current profiles as well as the dynamics of the turbulent dissipation rate compared to the steady-state law-of-the-wall. A logarithmic fit to the measured current profiles starting at a distance of 0.5 m above the sediment led to inconsistent estimates of both friction velocity and roughness length. Moreover, a phase lag between the current and the turbulent dissipation of 1.5 hours and a persistent maximum in the current profile at a height of 2.5 to 3 m above the sediment were observed. The experimental findings were compared to the results of a k- turbulence model and showed good agreement in general. Specifically, the inconsistent logarithmic fitting results and the observed phase lag were reproduced well by the model.     

集约化农区经济发展对耕地土壤有机碳含量变化的影响

陆地生态系统土壤有机碳储量变化是全球气候变化研究的重要方面,而耕地土壤有机碳含量是当中最活跃的部分,与人类利用行为以及社会经济发展水平相联系。文章选取黄淮海平原的北京市大兴区、河北省曲周县和黄土高原的山西省兴县的446个耕作层土壤20世纪80年代和2000年的有机碳含量数据和当地的社会经济、投入产出资料,结果表明:20年来,不同区域耕地土壤有机碳含量存在空间变异,但是其空间分布格局并未发生变化;对土地的集约利用并未造成土壤有机碳含量的降低,相反,各区域土壤有机碳含量普遍增加。结合相应的农户调查和统计资料,发现区域经济发展强烈地影响着土壤有机碳储量发生变化。无论自然条件优劣,还是经济发展水平处于何种阶段,经济的发展都能够促使农户增加对土地的投入,经济发达地区有充足的资金和市场保障,通过农业结构调整会增加对土地的投入;经济落后地区追求作物高产,促使土地投入也不断增加;使得作物经济产量和生物产量获得提高,促使耕地土壤有机碳含量增加。     

高寒草甸土地退化及其恢复重建对土壤碳氮含量的影响

针对我国青藏高原草地大面积退化及由此引发的一系列生态环境问题,从土壤生态功能恢复和区域可持续发展的角度出发,将原生高寒嵩草草甸封育系统作为对照,研究了土地退化对土壤碳氮含量的影响,检验了不同人工重建措施(3个人工种植处理:混播、松耙单播、翻耕单播和1个自然恢复处理)对土壤碳含量的相对影响程度。研究结果如下:原生植被封育处理每平方米土壤平均碳、氮含量分别为7.47kg和0.647kg,而重度退化地碳、氮含量分别为3.67和0.448kg·m-2,可以推算,由于土地退化而造成的土壤(0~20cm层)碳氮丢失量分别为3.80kg·m-2和0.199kg·m-2,即高寒草甸土地退化导致0~20cm土壤层中50.87%的有机碳和30.75%的氮流失,可以看出高寒草甸土壤退化后流失的碳比氮多;混播处理、松耙单播处理、翻耕单播处理和自然恢复处理土壤单位面积有机碳含量分别是原生植被土壤有机碳的70.5%,69.0%,49.0%和80%,单位面积氮含量分别是原生植被土壤全氮的86.9%,88.7%,71.1%和91.7%。但是,与重度退化地相比,除翻耕单播处理外,其它恢复重建措施均能部分恢复系统的碳氮含量,因此,将重度退化地进行自然恢复或松耙混播重建多年生植被可以作为系统固定碳(碳汇)的一个途径。     

大坞河流域重金属污染与五节芒光谱效应关系研究

以大坞河流域五节芒（Miscanthus floridulus）可见一近红外光谱以及叶片样本Cu、Zn、Fe元素质量分数监测数据为基础，对研究区内五节芒中重金属质量分数特征、光谱特征及两者的相关性进行了探讨。结果表明：五节芒叶片中3种金属元素的质量分数都较高；从上游到下游，五节芒叶片中Cu质量分数整体呈逐渐降低的趋势，五节芒光谱反射率在可见光区和近红外区均增加，红边“红移”（向长波方向飘移）强度逐渐减小；同时，五节芒叶片中Cu质量分数与五节芒可见光区、近红外区光谱反射率积分值呈负相关性，与红边“红移”强度、土壤中Cu质量分数呈正相关。并由此得出五节芒光谱特征中A1、A2、S等3项指标能够较好反映土壤的Cu污染程度，经进一步深入研究，可以将五节芒作为监测矿区土壤Cu污染的指示植物。