DYNAMIC RESPONSE OF AQUIFER SYSTEMS TO LOCALIZED RECHARGE1

ABSTRACT. The response of stream-unconfined aquifer systems to localized recharge is investigated by means of a two-dimensional finite element model. A variational approach is used in conjunction with the finite element method to solve the ground water flow equation. Linear approximated triangular elements are used to calculate the hydraulic head distribution in the flow region. The Crank-Nicholson centered scheme of numerical integration is employed to approximate the time derivative in the flow equation. A computer program is developed to calculate the hydraulic head distribution in the flow region. Solutions provided by the finite element model should prove useful in the evaluation of quantitative and qualitative changes in aquifer systems due to natural or artificial recharge. In addition, they should prove useful in the study of irrigation and drainage problems.     

论环境犯罪的构成要件

文章从环境犯罪的概念入手,进一步阐释环境犯罪的构成要件。通过对四个构成要件逐个剖析,对进一步完善环境刑法提出了自己的看法。     

Modelling of the relationship betwen trace elements and three species of sulfur in coal

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Complex behaviour of trivalent rare earth elements by humic acids

The complexation behaviours of trivalent rare earth elements (La, Ce, Ho and Yb) by two types of humic acids were investigated under a specified set of conditions. Humic acids show quite different complexation capacities an conditional formation constants with the REEs. Apparently there are two types of binding sites in the functional groups of humic acid, in which the first binding sites have stronger ability than the second. Cerium shows the largest complexation capacities and highest formation constants among the four REEs with two humic acids, this anomaly may be relative to the distribution pattern of the REEs in seawater. The experimental results were comparable to the values of other metals reported and provided the basic data for environmental geochemistry of rare earth elements.     

微量元素碘对儿童身心发育影响的研究

本文研究结果表明,在自然环境缺碘地区持续投放含碘浓度25ppm 的“NaCLI—固”后出生的儿童身高体重发育水平接近对照地区的中等水平;缺碘地区儿童甲状腺激素 T_4、T_3、T_4/T_3比值均在正常范围,甲状腺功能状态基本正常,提示机体内环境缺碘程度已得到纠正;缺碘区儿童 IQ 低下检出率明显高于对照区,血清 Zn 水平则无显著性差异,表明这部分低智儿童与在胚胎期间碘元素相对缺乏有着密切关系.     

用苋菜红体系催化光度法测定痕量碘

提供了痕量碘新的催化光度法测定方法,避免了原方法使用的剧毒试剂。新方法以草酸钠为活化剂,以高碘酸钾氧化苋菜红的催化反应为基点。方法的检出限为8×10~(-10)g/mL,测定碘离子量的线性范围为2.5×10~(-9)～1.3×10~(-7)g/mL,大多数常见离子不干扰测定。     

Preliminary study of the correlation between trace elementsin human hair, liver and kidney by protoninduced X-ray emission analysis

This paper deals with the determination of trace elements in normal human hair, liver and kidney by Proton Induced X-ray Emission (PIXE) analysis. Sampling, specimen preparation and experimental procedures are described in detail. The accuracy of our system has been checked up with the determination of standard reference materials. The preliminary results on correlations between trace elements in human tissues are discussed. Application of the method described in the paper gives evidence in favour of the PIXE as a good tool on environmental life elements and health studies.     

Co-exposure of sulfur nanoparticles and Cu alleviate Cu stress and toxicity to oilseed rape Brassica napus L.

Experiments were performed to explore the impact of sulfur nanoparticles (SNPs) on growth, Cu accumulation, and physiological and biochemical responses of oilseed rape (Brassica napus L.) inoculated with 5 mg/L Cu-amended MS medium supplemented with or without 300 mg/L SNPs exposure. Cu exerted severe phytotoxicity and inhibited plant growth. SNPs application enhanced the shoot height, root length, and dry weight of shoot and root by 34.6%, 282%, 41.7% and 37.1%, respectively, over Cu treatment alone, while the shoot and root Cu contents and Cu-induced lipid perodixation as the malondialdehyde (MDA) levels in shoots and roots were decreased by 37.6%, 35%, 28.4% and 26.8%. Further, the increases in superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), glutathione reductase (GR) and glutathione S-transferase (GST) enzyme activities caused by Cu stress were mitigated in shoots (10.9%–37.1%) and roots (14.6%–35.3%) with SNPs addition. SNPs also positively counteracted the negative effects on shoot K, Ca, P, Mg, Mn, Zn and Fe contents and root K, Ca, Mg and Mn contents from Cu exposure alone, and significantly promoted the nutrients accumulation in plant. Additionally, in comparison with common bulk sulfur particles (BSPs) and sulfate, SNPs showed more positive effects on promoting growth in shoots (6.7% and 19.5%) and roots (10.9% and 15.1%), as well as lowering the shoot Cu content (40.1% and 43.3%) under Cu stress. Thus, SNPs application has potential to be a green and sustainable technology for increasing plant productivity and reducing accumulation of toxic metals in heavy metal polluted soils.     

赣东北中生代火山岩微量元素与稀土元素丰度及其演化

本文论述了赣东北中生代火山岩中微量元素与稀土元素在不同岩性岩相及时空上的分布规律:潜火山岩中Au、Ag、Cu、Pb、Zn平均含量高于火山岩,尤以中酸性岩中较高,Ⅰ,Ⅱ旋回高于其他旋回。稀土元素由Ⅰ向Ⅱ旋回,由扬子地体向华夏地体,由爆发相向溢流相、潜火山岩相,由偏基性向中酸性岩演化;稀土配分模式是“L”型,火山岩物质来源于下地壳的部分熔融。     

中国癌症与土壤环境中化学元素的相关性研究

利用土壤元素数据2069448个，癌死亡调查资料787080例，研究了胃癌、食管癌、肝癌、宫颈癌、肺癌、大肠癌、白血病、鼻咽癌、乳腺癌死亡与人群生存的土壤环境中64个元素的相关性。得出了这些癌症死亡率与哪些元素呈正、负相关的统计结果。