基于AHP和DEA模型的农业生态效率评价——以无锡市为例

农业面源污染已成为我国重要环境污染源之一,但由于农业面源污染具有分散、面广、周期长、随机性等特点,在评价上存在较大难度。根据生态效率理论,结合农业生产的特点,建立了综合考虑经济效益和环境影响的农业生态效率评价指标体系,并以江苏省无锡市为例,选取该市1998~2008年农业生产和面源污染相关数据,运用偏好锥的数据包络分析模型（DEA）对其农业生态效率进行了评价分析。结果显示：1998~2008年,无锡市农业生态效率呈现先下降后上升的趋势,近三年累计上升幅度达22%。表明近年来无锡市农业面源污染治理成效显著,农业可持续发展水平显著提高。提出的农业生态效率评价体系和方法为进一步推进农业面源污染治理工作提供了依据     

基于网络层次分析法的石油化工设施安全风险评估

为评估石油化工设施的安全风险,提出了一种基于网络层次分析法的安全风险评估模型.在构建石油化工设施安全风险网络层次分析模型的基础上,采用Saaty标度法对安全风险参数进行量化,利用SD软件对安全风险参数进行排序.仿真结果表明,网络层次分析法考虑了安全风险参数之间的相互作用和相互影响,能改进基于线性组合关系的递阶层次分析模...     

提高电子元器件使用可靠性的方法

针对实际工作中元器件使用可靠性方面存在的问题．本文通过在实际工作的经验积累和技术研究总结,在电子元器件的选择与检测控制等方面,提出了提高电子元器件使用可靠性的方法。实践证明,这些方法可以直接应用于电子元器件的工程选择与检测控制。     

TOXIC TRACE ELEMENT POLLUTION IN GROUND WATERS AROUND PATANCHERU AND BOLARAM INDUSTRIAL AREAS, ANDHRA PRADESH, INDIA: A GRAPHICAL APPROACH

Patancheru and Bolaram are satellite industrial towns nearHyderabad with over 300 large andmedium scale pharmaceutical, heavy engineering, paints, paperand chemical factories. The industriesof the area generate a cumulative 8 × 10⁶ l/day ofeffluents which are being directly dischargedon to surrounding land, irrigation fields, and surface waterbodies which finally enter into theNakkavagu River a tributary of the Manzira River. The presentstudy on abundance and distributionpattern of toxic trace elements indicates the quantitativeaspect of pollution in the Nakkavagu Basin.Migration patterns drawn for TDS, toxic elements such as Cu,As, Se, Zn, B, Cr and iron indicate thatpollutants discharged by the industries are entering thesurface and groundwater system (aquifers) andare also migrating towards the Manzira River furtherdeteriorating the entire hydrological setup of the area.Entry and dispersion of pollutants in the hydrological systemis shown by distribution diagrams. Aconservative estimate indicates that the effect of pollutantson the agricultural lands and water bodiesextends 0.25 to 0.5 km to either side of the Nakkavagu Riverover a length of 25 km. In addition tothis, the movement of pollutants with ground water in thedownstream direction worsened thehydrological system and increased the possibility ofgeo-accumulation of pollutants in biota. Openwells, dug wells and tanks have become useless and redundantas the concentrations of Cu, Se, As,B, Cr and Fe have increased to 5 to 10 times the permissiblelimits. Several villages have beenaffected by the toxic pollutants in the area. The groundwatersystem is polluted over a large area asshown in elemental migration diagrams and is not potable.Tentatively an area of 20 sq km can becategorized as the worst affected by various pollutants.     

Elemental Analysis of Water and Sediments by External Beam Pixe Part 3: Axios (Vardar) River, Greece

The Axios (Vardar) River originates from the south west part of Yugoslavia, transverses Greece, and discharges into the Thermaikos bay in the north Aegean Sea.

The proton induced X-ray emission (PIXE) method with external beam was used for the elemental analysis of water and sediment samples, while measurements of water temperature, dissolved oxygen content, conductivity, pH, and the water flow were made in situ. Water samples were also analysed for total phosphates, nitrates, chlorophyll, and BOD. The data collected for a 16-month period indicate that the Axios River is polluted as far as the metal content is concerned; its primary productivity is low and it is slightly enriched during its course into the Greek territory.     

Behaviour of Chemical Elements in Plants and Soils

Neutron activation analysis was used for the determination of the elemental composition of different plants and soils. Variations in concentrations of elements during the day were found. Mean concentrations, standard deviations and relationships between elements in soils and different parts of plants were studied. It was shown that the behaviour of chemical elements in samples from urban and unpolluted areas have significant differences.     

Formulation of cleanup standards for trace elements with probability plots

Probability plots of trace element concentrations may be used to partition, or segregate, sample data into its constituent populations. Two populations are typically present in data from sites requiring remedial action, one representing clean, uncontaminated soil or sediment (background) and the other representing contaminated ground. The use of such plots in the analysis and evaluation of environmental data permits a statistical characterization of the background populations, from which defensible cleanup criteria may be developed. These criteria will be environmentally conservative, yet will minimize the amount of soil removed in a remedial action. An example is given from a successful cleanup of a surface impoundment.     

稀土元素对于减小电镀废液污染与提高钻头安全使用系数的作用研究

通过在生产电镀金刚石钻头的镀液中添加适当比例的稀土元素，可以促进毒性大，对环境污染严重的重金属离子的沉积，可以减小镀液浓度，控制污染总量，可以有效地提高电镀速度和电流效率，通过稀土元素在电镀钻头，热压钻头胎体中与其它有害物质的相互作用，改善了胎体性能，提高了钻头使用过程中的安全系数。     

Time series analysis of elemental and isotopic data from biomineralized whale tissue

A temporal record of environmental conditions is often contained within accretionary biological tissue. These records can provide knowledge of the environmental conditions that existed at the time the tissue was formed. In this study, we look at trace element concentrations and isotopic ratios of carbon and nitrogen as contained in baleen from bowhead whales in the eastern and western Arctic Ocean. Time series techniques, including maximum likelihood method and likelihood ratio tests, are applied to analysis of data and inference about their mean structures.     

川西前陆盆地流体的跨层流动

本文讨论了川西前陆盆地气田区上三叠统和侏罗系地层水K+ +Na+ 、Ca2 + 、Mg2 + 、Br-与Cl-离子、矿物 (胶结物和充填物 )碳氧同位素和水的氢氧同位素成分组成以及相互关系。气田区上三叠统流体来源以地层海陆相沉积物质为主 ,并与渗流水混合 ,形成“下部流体”。有气藏的侏罗系内流体 (称“上部流体”)与“下部流体”的水化学和同位素组成相近 ,且具有同一演化趋势 ,表明它来源于下部流体并与侏罗系层内的渗流水发生过混合作用。本文提出该气田流体具跨层流动、二次混合演化特征 ,认为大规模的流体对流混合促进了上三叠统内天然气的运移聚积 ,在三叠系内有利构造圈闭中形成原生或残留气藏并向上运移 ,在侏罗系内有利圈闭中形成“次生”气藏。