高邮地震台地电阻率观测精度干扰原因分析及排除方法

对高邮台地电NS向ρs的观测精度在2002 07 24雷雨后出现降低的现象进行了分析排查,发现是一交流接触器在遭雷击时烧坏,导致交流电三相中的一相对地漏电,与变压器中的零线形成回路所致。从而排除了配电房漏电的干扰,保证了观测资料的质量。     

MANGANESE IN LACUSTRINE ECOSYSTEMS: A REVIEW1

This paper serves as a literature review of manganese in fresh water. The major aspects of manganese occurrence discussed are: (1) sources, (2) geochemistry, (3) manganese-iron relationships, (4) effects on the fauna and flora and (5) detection.     

陕南化龙山珍稀濒危植物的保护和利用

化龙山是大巴山系在川陕境内的最高山峰,海拔２９１７．２ｍ,植物资源丰富,有野生维管植物１９７７种,隶属１８６科８１５属。化龙山是陕西省珍稀濒危植物资源最丰富的地区,共有国家保护的珍稀濒危植物２２科３０属３３种,其中属一级保护１种,二级保护１１种,三级保护２１种,属濒危２种,稀有１４各,渐危１７种,珍稀濒危植物古老成分较多,并以第三纪孑遗成分为主单少型属和中国特有属分别是１６属和１０属。这些珍稀濒危     

Radiocesium in North San Francisco Bay and Baja California coastal surface waters

Radiocesium, 137Cs, and rare earth elements (REEs) were determined in suspended material and dissolved fractions of waters across the salinity gradient in North San Francisco Bay (estuary). We describe the variation of this conservative isotope tracer with salinity and sediment load. REE data are used to differentiate marine and terrigenous source terrains for suspended material and dissolved fractions. We estimate that about 1-4 x 10(10) Bq of 137Cs migrates annually on suspended material through the North Bay. In addition, 137Cs concentrations were measured in surface waters off Baja California. Combined in situ water density (sigma(t)) and 137Cs data distinguish between California Current and Gulf of California water, and delineate areas of upwelling, where nutrient-rich, deep Pacific Intermediate water, with little or no 137Cs, is brought to the surface off promontories along Baja California.     

A FINITE ELEMENT MODEL OF CONTAMINANT MOVEMENT IN GROUNDWATER1

ABSTRACT. Transient, two-dimensional solutions are developed which describe the movement and distribution of a conservative substance in a stream-aquifer system. The solutions are obtained by solving sequentially the groundwater flow and mass transport equations. A variational approach in conjunction with the finite element method is used to solve the groundwater flow equation. Galerkin's approach coupled with the finite element method is used to solve the mass transport equation. Linear approximated triangular elements and a centered scheme of numerical integration are employed to calculate the hydraulic head distribution and the concentration of solute in the flow region. The linear approximation used to define the concentration function within each element is not appropriate for cases involving steep concentration gradients. For such cases, higher order approximations are necessary to assure the continuity of gradients across interelemental boundaries. Numerical examples that illustrate the applicability of the model are presented.     

WATER RESOURCES AND HUMAN HEALTH: THE VIEWPOINT OF MEDICAL GEOGRAPHY1

ABSTRACT: Medical geography studies both areal patterns of human health and disease and the environmental and cultural factors that contribute to such conditions. In such studies water resources are of major importance, not only because they are essential for life and their scenic beauty is of inspirational value, but also because they are involved, directly or indirectly, in more than 80 percent of all disease. The direct involvements result from various disease causing agents sometimes found in surface or ground water organic ones such as bacteria, worms, etc., which are known as pathogens, and inorganic ones such as trace elements and synthetic toxic chemicals. Surface waters may have indirect effects also, for they may serve as habitats or breeding places for organisms that do not themselves cause human disease but that serve as vectors or hosts for such pathogens. This paper will discuss these various roles of water resources in both endemic and epidemic disease occurrences and ways in which various human activities domestic, economic, recreational, or religious — increase or reduce our exposure to such diseases.     

Chemical pollution: Transfer of chemical elements to the aboverground phytomass of herbaceous plants

Changes in the species composition and a decrease in species diversity and total plant biomass along the gradient of soil pollution with heavy metals have been shown. Data on the concentrations of chemical elements (Zn, Cu, Cd, Pb, Co, Ni, Mn, Cr, and Fe) in the aboveground organs of herbaceous plants and the biomass of each species make it possible to estimate the role of higher producers in the incorporation of chemical elements into biogenic cycles in background zones and under conditions of chemical pollution. Plants of the composite family (Asteraceae) play the main role in accumulation of chemical elements. The results obtained indicate that natural ecosystems have mechanisms limiting excessive accumulation of chemical elements into the aboveground plant biomass.     

Development and Validation of the Total HUman Model for Safety (THUMS) Toward Further Understanding of Occupant Injury Mechanisms in Precrash and During Crash

Objective: Active safety devices such as automatic emergency brake (AEB) and precrash seat belt have the potential to accomplish further reduction in the number of the fatalities due to automotive accidents. However, their effectiveness should be investigated by more accurate estimations of their interaction with human bodies. Computational human body models are suitable for investigation, especially considering muscular tone effects on occupant motions and injury outcomes. However, the conventional modeling approaches such as multibody models and detailed finite element (FE) models have advantages and disadvantages in computational costs and injury predictions considering muscular tone effects. The objective of this study is to develop and validate a human body FE model with whole body muscles, which can be used for the detailed investigation of interaction between human bodies and vehicular structures including some safety devices precrash and during a crash with relatively low computational costs.

Methods: In this study, we developed a human body FE model called THUMS (Total HUman Model for Safety) with a body size of 50th percentile adult male (AM50) and a sitting posture. The model has anatomical structures of bones, ligaments, muscles, brain, and internal organs. The total number of elements is 281,260, which would realize relatively low computational costs. Deformable material models were assigned to all body parts. The muscle–tendon complexes were modeled by truss elements with Hill-type muscle material and seat belt elements with tension-only material. The THUMS was validated against 35 series of cadaver or volunteer test data on frontal, lateral, and rear impacts. Model validations for 15 series of cadaver test data associated with frontal impacts are presented in this article. The THUMS with a vehicle sled model was applied to investigate effects of muscle activations on occupant kinematics and injury outcomes in specific frontal impact situations with AEB.

Results and Conclusions: In the validations using 5 series of cadaver test data, force–time curves predicted by the THUMS were quantitatively evaluated using correlation and analysis (CORA), which showed good or acceptable agreement with cadaver test data in most cases. The investigation of muscular effects showed that muscle activation levels and timing had significant effects on occupant kinematics and injury outcomes. Although further studies on accident injury reconstruction are needed, the THUMS has the potential for predictions of occupant kinematics and injury outcomes considering muscular tone effects with relatively low computational costs.     

突发事件情景演化及关键要素提取方法

针对突发事件应急处置难度大的特点,突发事件应急管理模式必须向"情景-应对"转变。从系统复杂性、开放式预先设想以及序贯性三个主要原则的角度理解突发事件情景演化的机理,构建了突发事件情景演化系统模型,并以此为基础设计了突发事件情景网络关键要素的提取方法。该方法以危险源形成、突发事件演化以及应急响应三方面主要内容为情景网络的主体,以三方面主要内容所涉及的影响因素为分支,适当的选取情景网络关键要素并将关键要素分为四类。该方法的提出弥补了情景网络关键要素提取方法理论的空白,为突发事件情景构建提供了理论支持。     

Trace elements in particulate matter of ambient air at petroleum filling stations

Size segregated suspended particulate matter (PM_2.5 and PM_10-2.5) in air at four major petroleum-filling stations in Ile-Ife, Nigeria, were monitored using double staged “Gent” stacked samplers to assess variations in mass loads and elemental concentrations of 25 elements. Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr, Zr, Cs, Ta, W, and Pb were determined in both fractions by external ion beam proton-induced X-ray emission technique. Enrichment factors and pollution indices were calculated and results revealed that most elements were anthropogenic in both fractions with concentrations exceeding the World Health Organization guideline standards.