城市化对南京地区土壤多样性影响的灰色关联分析

随着城市化的发展,越来越多的土壤资源被侵占。本文借助RS和GIS技术,根据1984年、1995年、2003年3期TM遥感影像 (30m×30m),采用多时相连续对比法对南京地区近20年来城镇扩张情况进行了分析;结合南京地区土壤图,利用生态学领域中的多样性测度方法计算了城市化背景下南京地区的土壤多样性指数 (HP)、土壤均匀度指数 (Jsw) 和土壤丰富度指数 (R₂),进而在镇级尺度上对1984~2003年南京地区土壤多样性时空变化特点进行了研究;利用灰色系统理论中的灰色关联分析方法,对南京地区各级行政区划单位的扩张对土壤多样性的影响进行了初步探讨。分析结果表明,各级行政区划中村庄的扩张对土壤多样性指数的影响最广,约占研究区总面积的60%;镇、县和市的扩张对土壤多样性的影响逐渐减少,各占研究区总面积的26%、7%和7%。     

Coal price fluctuation mechanism in China based on system dynamics model

Natural Hazards - We analyze and identify the factors that influence coal price fluctuations and construct a system dynamics model of these factors. The simulation results show that the trend in...     

The suitability of using leaf area index to quantify soil loss under vegetation cover

Soil erosion by water under forest cover is a serious problem in southern China. A comparative study was carried out on the use of leaf area index (LAI) and vegetation fractional coverage (VFC) in quantifying soil loss under vegetation cover. Five types of vegetation with varied LAI and VFC under field conditions were exposed to two rainfall rates (40 mm h⁻¹ and 54 mm h⁻¹) using a portable rainfall simulator. Runoff rate, sediment concentration and soil loss rate were measured at relatively runoff stable state. Significant negative exponential relationship (p < 0.05, R² = 0.83) and linear relationship (p < 0.05, R² = 0.84) were obtained between LAI and sediment concentration, while no significant relationship existed between VFC and sediment concentration. The mechanism by which vegetation canopy prevents soil loss was by reducing rainfall kinetic energy and sediment concentration. LAI could better quantify such a role than VFC. However, neither LAI nor VFC could explain runoff rate or soil loss rate. Caution must be taken when using LAI to quantify the role of certain vegetation in soil and water conservation.     

苏州城郊土地利用变化对土壤的影响

1IntroductionThe conversion of natural systems to agricultural production has been the primary basis for the successful growth of human populations for the last 9,000 years (Kates etal., 1990). The conflict between urban and agricultural land use, however…     

我国首次发现的硫铋铅铁铜矿

本文研究的硫铋铅铁铜矿是1986年采自河北省青龙县三家金矿。利用反光显微镜、MPV-1型显微光度计、显微硬度计、JCXA—733型电子探针、X射线粉晶分析等手段对该矿物进行了研究。获得其平均化学成分为:S 20.92％,Bi 22.47％,Pb 23.40％,Fe 6.30％,Cu26.48％。硬度为191.5—217kg/mm~2及其他数据。将获得的各项参数与日本三原铜矿产出的硫铋铅铁铜矿进行了对比,确认其为硫铋铅铁铜矿。这在我国是首次发现和报道。     

广东莲花山钨矿床中分散钨赋存情况及有用元素综合利用的研究

在承担《南岭地区典型钨矿床矿石物质成分及综合利用前景研究》专题中,应广东莲花山钨矿的要求,重点对该矿床三号矿体进行了野外观察,采样及大量室内工作,在分散钨,有价元素的赋存状态,空间分布及其综合利用的研究方面比前人有所前进.     

中国某些金矿床中碲化物的特征

我国含碲化物的金矿床主要有４种类型,太古宙花岗－绿岩地体中的含金石英脉型矿床、元古宙火山岩中的蚀变构造岩型金矿床、中－新生代火山岩中的浅成低温热液金银矿床,与花岗岩有关的金矿床。总结了我国已发现的碲化物的光学性质,硬度及其共生组合特征,列出了主要碲化物的电子探针定量分析结果,最后讨论了碲化物形成的某些地球化学习性,碲化物总是与自然金一起形成于矿化的晚期,这表明它与金有某些一致的地球化学习性,并可能     

The impact of international crude oil price fluctuation on the exchange rate of petroleum-importing countries: a summary of recent studies

Natural Hazards - Oil is an important energy resource. Fluctuation in international crude oil prices affects all aspects of the economy. The exchange rate is one of the important channels for the...     

三家金矿发现Hg—Au—Ag矿物—α—汞金银矿

a-汞金银矿是1986年笔者在河北省青龙县三家金矿某富矿带采集的金矿石标本中发现的,见于矿石光片及人工重砂中。经电子探针分析,平均含Ag 41.53%,Au 22.34%,Hg 36.09%,简化化学式为:(Ag,Au)3Hg。其x射线粉晶数据为:2.382(9) (111),2.060(6)(200),1.461(7)(220),1.245(10)(311),1.194(5)(222),与1929年Pabst等人合成的a汞金矿(含Au 82.75%)可以比较,属等轴晶系。笔者确定它为Hg、Au、Ag金属互化物,且是Hg-Au-Ag系列矿物的新变种。