中国九个内陆盐湖卤虫的品系特征

分析了中国９个内陆盐湖卤虫的生物学测定值,孵化特性,蛋白质含量和脂肪酸组成,不同品系的卤虫在卵径,无节幼体体长,脱壳卵和无节幼体干重等生物学测定值方面存在着极其显著的差异（Ｐ〈０．０１）。     

巢湖蓝藻水华藻胆蛋白的分离与鉴定

在高温季节,巢湖等国内淡水湖中蓝藻大量繁殖常形成蓝藻湖靛(主要由微囊藻组成),它含有丰富的蛋白质、氨基酸、脂肪等营养成分.本文对微囊藻中氨基酸的组成及含量进行了测试,并从其中提取、分离纯化了藻胆蛋白(指其中的藻蓝蛋白和别藻蓝蛋白),最后运用紫外可见光谱对其进行了检测,取得了较为满意的结果.这也为进一步开发利用巢湖湖靛提供了依据。     

垦丁国家公园内南仁湖的地球化学

南仁湖区位于台湾省屏东县满州乡境内,是一个封闭且独立的盆地,土壤属于洪积层发良之红壤,是经过强烈淋洗后的风化产物。成分以粘土矿物为主,低价元素皆在风化过程中大量流失,呈强酸性反应(pH值为3.65—5.30)。淋洗出的土壤渗滤水pH值介於5.O左右,碱度几乎全在0.020 m mol(+)/L以下,没有提供大量碱度到湖水中,和一般沉积岩区土壤渗滤水不同。湖水中的叶绿素a含量大多数在10μg/L之上,属于富营养化的水域;碱度大部分在O.20 m mol(+)/L以下,属为对酸敏感到极敏感湖之列;磷含量已多在20μg/L以上,在分类上亦属于富营养阶段;氮和磷的比值相当低,因此氮成为水中浮游生物的主要生长限制元素;其他主要离子的来源受控于当地环境和雨水及海水飞沫的影响。为了解影响湖水化学组成的主要因素,作者收集南仁湖区的雨水、土壤渗滤水和湖水,以求了解其各别的离子含量及变化;同时还测量湖水流出量,并收集相关气象资料,企图计算出各种离子在集水区中的收支情况。经过实验及计算,估计雨水在1989年输入大约167×10~3mol(+)的离子,占年度总输入量的6％左右,其余则来自陆地;大约577×10~3mol(+)的主要离子从出水口流出南仁湖,约占总输入量的19％,其余的离子累积于湖盆中。显见陆源水的化学物质含量是影响南仁湖水质及化学组成的主要因素。水中有机质以33.7—52.9mg/cm~2·a的速率累积于南仁湖沉积物中,沉积物的总累积速率为581—911mg/cm~2·a。     

Mobility of major ions and nutrients in the unsaturated zone during paddy cultivation: a field study and solute transport modelling approach

Study of the movement of water and solute within soil profiles is important for a number of reasons. Accumulation of prominent contaminants from agricultural chemicals in the unsaturated zone over the years is a major concern in many parts of the world. As a result, the unsaturated zone has been a subject of great research interest during the past decade. Hence, an intensive field study was conducted in a part of Palar and Cheyyar river basins to understand the variation of major ions and nutrients in the soil zone during paddy cultivation. The chloride and nitrate data were used to model the movement of these chemicals in the unsaturated zone using the HYDRUS‐2D model. The field study shows that fertilizer application and irrigation return flow increases the major ions and nutrients concentration in the unsaturated zone. Further, the nutrient concentrations are regulated by plant uptake, fertilizer application and infiltration rate. Additionally, denitrification and soil mineralization processes also regulate the nitrogen concentration in the unsaturated zone. The solute transport modelling study concluded that the simulated results match reasonably with the observed trends. Simulated concentrations of chloride and nitrate for a 5‐year period indicate that the concentrations of these ions fluctuate in a cyclic manner (from 60 to 68 mg l^?1 and from 3·4 to 3·5 mg l^?1 respectively in groundwater) with no upward and downward trend. The influence of excessive fertilizer application on groundwater was also modelled. The model predicts an increase of about 17 mg l^?1 of chloride and 2·3 mg l^?1 of nitrogen in the groundwater of this area when the application of fertilizers is doubled. The model indicates that the present level of use of agrochemicals is no threat to the groundwater quality. Copyright © 2007 John Wiley & Sons, Ltd.     

Steady infiltration from buried point source into heterogeneous cross‐anisotropic unsaturated soil

The paper presents the analytical solution for the steady‐state infiltration from a buried point source into two types of heterogeneous cross‐anisotropic unsaturated half‐spaces. In the first case, the heterogeneity of the soil is modelled by an exponential relationship between the hydraulic conductivity and the soil depth. In the second case, the heterogeneous soil is represented by a multilayered half‐space where each layer is homogeneous. The hydraulic conductivity varies exponentially with moisture potential and this leads to the linearization of the Richards equation governing unsaturated flow. The analytical solution is obtained by using the Hankel integral transform. For the multilayered case, the combination of a special forward and backward transfer matrix techniques makes the numerical evaluation of the solution very accurate and efficient. The correctness of both formulations is validated by comparison with alternative solutions for two different cases. The results from typical cases are presented to illustrate the influence on the flow field of the cross‐anisotropic hydraulic conductivity, the soil heterogeneity and the depth of the source. Copyright © 2004 John Wiley & Sons, Ltd.     

Development of a technique for modelling clay liner desiccation

This paper presents a model for the analysis of clay liner desiccation in a landfill barrier system due to temperature effects. The model incorporates consideration of fully coupled heat‐moisture‐air flow, a non‐linear constitutive relationship, the dependence of void ratio and volumetric water content on stress, capillary pressure and temperature, and the effect of mechanical deformation on all governing equations. Mass conservative numerical schemes are proposed to improve the accuracy of the finite element solution to the governing equations. The application of the model is then demonstrated by examining three test problems, including isothermal infiltration, heat conduction and non‐isothermal water and heat transport. Comparisons are made with results from literature, and good agreement is observed. Copyright © 2003 John Wiley & Sons, Ltd.     

Humic Acid and Iron Chelation Modified Anode Improves the Electrochemical Performance of Marine Sediment Microbial Fuel Cell

Marine sediment microbial fuel cell(MSMFCs)can be utilized as a long lasting power source to drive small instruments to work for long time on ocean floor and its higher power has a significant meaning for practical application.Anode modification can greatly improve the performance of MSMFCs.Herein,humic acid(HA)and humic acid-iron ion complex(HA-Fe)were used to modify the anode for constructing a better MSMFCs.The results indicated that HA-Fe modified anode,better than HA modification,significantly improved the MSMFCs cell power output.The maximum power density of HA-Fe modified MSMFCs is 165.3 mW m?2,which are 6.5-folds of blank MSMFCs.The number of microorganisms on anode,redox activity,and relative kinetic activity were 1.8-,6.1-,and 13.1-folds of blank MSMFCs,respectively.The MSMFCs improvement would be attributed to the electron transfer media of HA and the valence conversion of Fe ions.A synergistic interaction between the naturally occurring HA and Fe ions on the anodic surface in marine sediments would make the modified anodes have‘renewable’characteristics,which is beneficial for the MSMFCs to maintain its long-term higher power.     

浅层地下水中磺胺嘧啶与胡敏酸相互作用及相态间分布特征

研究抗生素在浅层地下水中不同相态间的分布特征,对于了解抗生素的行为特征及评估其危害具有重要的意义。本文利用三维荧光淬灭法研究了胡敏酸(humic acid, HA)对磺胺嘧啶(sulfadiazine, SD)在地下水中不同相态间分布规律的影响及相互作用,探讨了HA浓度、pH值、温度对SD在不同相态间分布的影响,对淬灭过程进行拟合并计算了分配系数、淬灭参数以及热力学参数。结果表明:地下水中SD浓度(0.5 mg/L)较低时或者HA浓度增加(0~20 mg/L)时,HA可显著促进悬浮相中SD比例的增加;SD对HA的淬灭机理为形成复合物的单一静态淬灭,结合位点数均约为1,荧光淬灭常数K_sv为5.271×10³ L/mol,淬灭速率常数K_q为5.271×10¹¹ L/(mol·s),属于自发的放热过程;体系处于低温(15 ℃)、弱碱性(8~10)pH值环境时,SD对HA的淬灭作用最强,HA对SD进入悬浮相的促进作用最明显。     

常压酸溶-电感耦合等离子体质谱法测定地球化学勘查样品中的铌钽

常压酸溶法因溶矿效率高、成本低、检出限低,在地质实验室被广泛应用,但采用常用的氢氟酸-硝酸-盐酸-高氯酸四酸法处理样品,铌钽溶出率低,铌钽在容器壁发生水解和聚合反应导致其部分吸附或沉降,从而使测试结果偏低。因此,应用常压酸溶-电感耦合等离子体质谱(ICP-MS)分析地球化学勘查样品中的铌钽,需要解决的两个关键问题是铌钽的溶出率和试液中铌钽的水解。针对溶出率的不足,本方法在酸体系中引入硫酸,即氢氟酸-硝酸-盐酸-高氯酸-硫酸可以完全将铌钽溶出;针对水解,采用5%氢氟酸-5%硫酸-5%过氧化氢为提取剂,并采取与样品前处理相同分析流程的标准物质制作曲线,这两个方法相结合能有效抑制样品溶液中铌钽的水解,同时标准物质制作曲线法降低了ICP-MS分析中的样品溶液与标准溶液基体不一致引起的误差。本方法经国家标准物质验证,相对误差小于±7%,相对标准偏差在3.11%~6.27%之间(n=11),铌钽的检出限分别为0.04μg/g和0.03μg/g,相比于碱熔法检出限0.33μg/g具有明显优势,可以准确测定地球化学勘查样品中的铌钽。