钨矿石和锡矿石化学成分分析能力验证结果评价和离群值原因

金属矿产的勘查、评价、开发与综合利用要求对不同矿石品位与精矿的完整系列品质进行评价检测和仲裁测试。钨矿石和锡矿石作为金属矿的重要矿种,在客观上要求相关实验室应具备不同含量品级钨矿石和锡矿石组分的检测能力。本文按照国家认证认可监督委员会(CNCA)编号为CNCA-13-A14的钨矿石和锡矿石化学成分分析能力验证计划的要求,对中国30个省市、自治区的58个实验室提供的8个元素(W、Sn、Cu、Pb、Zn、Mo、Sb、Bi)的测定结果进行能力验证分析,采用稳健统计法,根据Z比分数判定参加实验室的检测能力。根据Z比分数≤2为满意结果的判定标准,51个实验室全部结果的Z比分数≤2,总体结果满意率(各元素的Z比分数均≤2的实验室占总实验室的比例)为88%,出现可疑和离群结果的实验室占12%。总体上钨矿石和锡矿石中元素Sb、Pb、Zn的满意率较高(其中锡矿石的Zn测定结果全部满意),W、Bi稍差;钨矿石各元素的检测水平差异小,整体结果好于锡矿石。钨矿石和锡矿石分析能力验证结果产生离群值的原因,一方面是实验室的测试水平存在差异;另一方面是各实验室采用的检测方法分散,有化学分析方法和仪器分析方法,化学分析方法检测步骤多,仪器分析方法方便快速,逐渐成为例行检测方法,两类方法的影响因素都较多。本文提出,提高实验室的检测水平和检测能力,需要适当统一检测方法,提高方法掌握的熟练程度,避免仪器状态对分析结果的影响,确保检测结果的一致性和准确性。     

城市小型河流水动力弥散和潜流交换过程

为研究城市小型河流中污染物的物理迁移过程规律,分析基流条件下流动水体与暂态存储区之间的滞留交互作用,采用溴化锂(LiBr)作为保守性示踪剂进行野外现场示踪试验,结合一维溶质运移存储模型(One-dimensional Transport with Inflow and Storage model, OTIS)定量解析潜流交换特性,估算纵向弥散系数(D)、潜流交换面积(A_s)、主河道断面面积(A)和潜流交换系数(α).模型度量指标D_aI值和均方根误差值结果表征参数模拟结果可靠性高,拟合效果理想.由泵入点O至下游1 300 m设置的A、B、C、D 4处监测点的模拟结果表明,水文参数D、A_s、A和α均随水文条件而变,OB河段(0~600 m)潜流交换能力较弱,主要以对流弥散过程为主;BD河段(600~1 300 m)具有较强的暂态存储能力,对溶质的滞留时间长;BC(600~1 000 m)和CD(1 000~1 300 m)河段交换系数分别为(3.42×10-6±0.65×10-6)s-1和(2.87×10-6±0.81×10-6 )s-1;河段BC存在2.2×10-5m3/(s·m)的侧向补给流量.4个河段对比发现,城市河流渠道化、河床沉积物贫瘠等特征导致潜流交换能力弱化.     

暗物质粒子探测器触发逻辑测试系统的设计和实现?

作为暗物质粒子探测器(DAMPE, Dark Matter Particle Explorer)的一部分,触发系统主要用于判选所需探测的目标粒子(高能电子和伽玛射线)事例,剔除非目标粒子事例。触发系统由触发探测器和触发判选逻辑电路组成。介绍了触发地检测试系统和宇宙线触发系统的设计和功能实现。触发地检系统实现了对触发判选逻辑电路的电子学验证;另外,配合宇宙线触发系统对部分触发逻辑和触发效率进行了测试。主要介绍了触发系统的测试方法和一些初步测试结果。     

Hydrogeological aspects of groundwater drainage of the urban areas in Kuwait City

Residential areas in Kuwait City have witnessed a dramatic rise in subsurface water tables over the last three decades. This water rise phenomenon is attributed mainly to over irrigation practices of private gardens along with leakage from domestic and sewage networks. This paper presents a comprehensive study for urban drainage in two selected areas representing the two hydrogeological settings encountered in Kuwait City. In the first area, a vertical drainage scheme was applied successfully over an area of 1 km². The system has been under continuous operation and monitoring for more than 4 years without problems, providing a permanent solution for the water rise problem in this area. The hydrogeological system has approached steady state conditions and the water levels have dropped to about 3·5 m below the ground surface. In the second area a dual drainage scheme, composing of horizontal and vertical elements, is proposed. Horizontal elements are suggested in the areas where the deep groundwater contains hazardous gases that may pose environmental problems. The proposed drainage scheme in the second area has not yet been implemented. Field tests were conducted to assess the aquifer parameters in both areas and a numerical model has been developed to predict the long‐term response of the hydrogeological system in the two areas under consideration. Copyright © 2001 John Wiley & Sons, Ltd.     

BOOK REVIEWS

Books reviewed in this article: Aerial Photography and Remote Sensing Aerial photography and image interpretation for Resource Management . DAVID P. PAINE . Analytical Models and Techniques Spatial Processes Models and Applications A. D. CLIFF AND J. K. ORD Quantitative and Statistical Approaches to Geography: A Practical Manual JOHN A. MATTHEWS . Cartography and Maps Map Data Processing . HERBERT FREEMAN AND GOFFREDO G. PIERONI , eds. Computer-assisted Cartography: Principles and Prospects, 1982 . MARK S. MONMONIER . Cultural Navajo Architecture: Forms, History, Distributions . STEPHEN C. JETT AND VIRGINIA E . SPENCER . Rational Landscapes and Humanistic Geography . EDWARD RELPH . Economic The Structure and Control of a State Economy . W. L. L'ESPERANCE . Economic Geography . JAMES O. WHEELER AND PETER O. MULLER . The Myth of the Family Farm: Agribusiness Dominance of U.S. Agriculture . INGOLF VOCELER . Libya: The Experience of Oil . J. A. ALLEN . Geography of Public Finance, Welfare Under Fiscal Federalism and local Government Finance . ROBERT BENNETT . Environmental Management, Resources, and Systems Mountains and Man . LARRY W. PRICE . Environmental Geology . DONALD R. COATES . An Introduction to Environmental Systems . G. H. DURY . The Environment: Chinese and American Views . Edited by LAURENCE J. C. MA AND ALLEN G. NOBLE . Land Use in America . RICHARD H. JACKSON . Medical Conceptual and Methodological Issues in Medical Geography . MELINDA S. MEADE (ed.). Philosophy and Geographic Thought Birds in Egg/Eggs in Bird . GUNNAR OLSSON . PhysicaI Climatology: Selected Applications . J. E. OLIVER . Geomorphological Techniques . ANDREW GOUDIE (ed.). Political Politics, Geography and Behaviour . RICHARD MUIR AND RONAN PADDISON . The State of the World Atlas . MICHAEL KIDRON AND RONALD SECAL . Population The Population of the South . DUDLEY L. POSTON , JR . AND ROBERT H. WELLER , eds. Regional Latin America: Economic Development and Regional Differentiation . ARTHUR MORRIS . Developing the Amazon . EMILIO F. MORAN . Western Europe: A Systematic Human Geography . BRIAN W. ILBERY . Settlement Systems in Sparsely Settled Regions: The United States and Australia . RICHARD E. LONSDALEAND JOHN H. HOLMES , eds. African Perspectives: The Economic Geography of Nine African States . HARM DE BUJ AND ESMOND MARTIN , eds. Rural Nonmetropolitan America in Transition . AMOS H. HAWLEY AND SARA MILLS MAZIE , eds. Social Crime and Environment . R. NORMAN DAVIDSON . The Ghetto: Readings with Interpretations . JOE T. DARDEN , ed. Urban Urban Problems and Planning in the Developed World . MICHAEL PACIONE (ed.) Problems and Planning in Third World Cities . Edited by MICHAEL PACIONE . The City in West Europe . D. BURTENSHAW , M. BATEMAN , AND C. J. ASHWORTH .     

Higher Dimensional Cosmological Implications Of A Decay Law For λ Term: Expressions For Some Observable Quantities

Implications of cosmological model with a cosmological term of the form , where β is a constant, are analyzed in multidimensional space time. The proper distance, the luminosity distance-redshift, the angular diameter distance-redshift, and look back time-redshift for the model are presented. It has been shown that models are found to be compatible with the present observations. This work, has thus generalized to higher dimensions the well-known result in four dimensional space time. It is found that the difference is significant at least in the principal to the anologous situation in four dimensional space time.     

LABORATORY OBSERVATIONS OF SEDIMENT ENTRAINMENT BY FREEZING SUPERCOOLED WATER

Debris in basal ice produced by glaciohydraulic supercooling is typically characterized by high proportions of silt. A prominent hypothesis for this silt‐dominance is that frazil ice growing in supercooled water preferentially traps silt from sediment‐laden water percolating through it. It has therefore been suggested that silt‐dominance may be diagnostic of glaciohydraulic supercooling. The aim of our work is to test this hypothesis that freezing sediment‐laden supercooled water necessarily produces ice dominated by silt. We do this by simulating two freezing processes under laboratory conditions: (1) percolation of sediment‐laden water through frazil ice; (2) turbulent supercooling and subsequent freezing of sediment‐laden water. In experiments repeated using different particle sizes (sand, silt and clay in individual experiments) both processes entrained sand most effectively and silt least effectively. In experiments using a sediment mixture dominated by medium to coarse silt, both processes produced ice facies dominated by particle sizes between fine sand and coarse silt. These results suggest that silt‐dominance should therefore not be expected for supercooled freeze‐on, and is not a reliable diagnostic signature for supercooling. The silt‐dominated character of basal ice types associated with supercooling may result from other controls such as a silt‐dominated sediment supply or subglacial water flow rates, rather than the freezing process.     

Radiative lifetimes and transition probabilities in Hf I and Hf III

Radiative lifetimes of nine odd levels in Hf III (5d6p z³P_0,1, z¹D₂, z³D_1,2,3, z³F_2,3,4) and of two odd levels in Hf I (5d6s²6p z³D_2,3) have been determined using Time-Resolved Laser-Induced Fluorescence. The investigated levels in Hf I were excited in a single-step process from the ground term (5d²6s² a³F), whereas in Hf III we started from either the ground term 5d² a³F or the low-lying 5d6s a³D term. For all of the investigated levels, the lifetimes have been measured for the first time. A multiconfiguration relativistic Hartree–Fock method, including core-polarization effects, has been used to compute radiative lifetimes of 15 Hf III levels, including those measured in this work. Transition probabilities for 55 transitions in Hf III are also given.