某矿山天然放射性核素的调查

对某矿山工作场所和生活区分别进行了样品采集,并使用ORTEC公司生产的16000道HPGeγ能谱仪进行了测量。结果表明,该矿山工作场所天然放射性核素的比活度大多高于生活区,其中危害最大的为尾矿坝;某些生活区天然放射性核素的比活度比对照点和国家均值要高,但多数都在国家均值范围内,最高值出现在3号生活区的农田土样中,其天然放射性核素的比活度分别为：α（226^Ra）——750．4Bq/kg、α（232^Th）——91．5Bq/kg、α（40^K）——1202Bq/kg。     

地图误差对地图匹配质量的影响

高精度的数字地图是正确匹配车辆位置的基础。详细分析了地图数据的地理误差和拓扑误差的误差形式,路网数据模型的常见误差因素和改进策略,最后介绍了不同地图匹配算法对地图质量的敏感性和可行性。根据可能出现的误差对现有数字地图和匹配算法加以改进,弥补了原有数字地图带来的不精确缺陷。跑车实验证明,考虑了数字地图误差影响的匹配算法可以明显提高定位精度,减小车辆定位误差。     

晚新生代亚洲干旱气候发展与全球变冷联系的风尘沉积证据

在干旱气候背景下常常有风尘物质的释放和传输,风尘沉积被认为是干旱环境变化良好的地质记录。在亚洲中部和中国北方,大面积的干旱区被沙漠戈壁覆盖,这些地区是粉尘物质的重要源地,释放的风尘物质影响局地和区域环境,并通过参与生物地球化学循环等影响更大空间尺度的气候变化。因此,亚洲中部干旱气候的形成和演化以及发展趋势一直受到重视。长期以来,关于晚新生代亚洲中部干旱气候发展的驱动机制至少有两种解释:一是青藏高原的隆升控制着亚洲中部的干旱化过程,随着高原的阶段性隆升亚洲干旱气候逐步增强;二是晚新生代全球变冷直接驱动着亚洲变干,全球变冷是主导因素。中国黄土高原及其周边地区堆积的黄土-红粘土序列是指示亚洲干旱化过程良好的地质记录,通过对新获得的风尘堆积记录的分析,发现在晚新生代中国风尘堆积的时空演化与全球变冷有较好的对应,全球变冷可以促使亚洲中部干旱气候发展并加强粉尘活动,而青藏高原隆升的幅度和时间还不清楚,进而认为是全球变冷而不是青藏高原隆升直接驱动亚洲内陆的阶段性变干。基于这些结果,我们认为以前关于青藏高原隆升影响全球气候的结论可能高估了青藏高原在地球环境演化中的作用,关于高原隆升直接驱动亚洲干旱化的结论还需要检验。     

A sub-pixel analysis of urbanization effect on land surface temperature and its interplay with impervious surface and vegetation coverage in Indianapolis,United States

This study developed an analytical procedure based upon a spectral unmixing model for characterizing and quantifying urban landscape changes in Indianapolis, Indiana, the United States, and for examining the environmental impact of such changes on land surface temperatures (LST). Three dates of Landsat TM/ETM+ images, acquired in 1991, 1995, and 2000, respectively, were utilized to document the historical morphological changes in impervious surface and vegetation coverage and to analyze the relationship between these changes and those occurred in LST. Three fraction endmembers, i.e., impervious surface, green vegetation, and shade, were derived with an unconstrained least-squares solution. A hybrid classification procedure, which combined maximum-likelihood and decision-tree algorithms, was developed to classify the fraction images into land use and land cover classes. Correlation analyses were conducted to investigate the changing relationships of LST with impervious surface and vegetation coverage. Results indicate that multi-temporal fraction images were effective for quantifying the dynamics of urban morphology and for deriving a reliable measurement of environmental variables such as vegetation abundance and impervious surface coverage. Urbanization created an evolved inverse relationship between impervious and vegetation coverage, and brought about new LST patterns because of LST's correlations with both impervious and vegetation coverage. Further researches should be directed to refine spectral mixture modeling by stratification, and by the use of multiple endmembers and hyperspectral imagery.     

Geochemistry and environmental effect of cadmium in the super-large Jinding Pb-Zn deposit,Yunnan Province,China

The Jinding Pb-Zn deposit in Yunnan Province is the representative of a Cd-enriched area and mining activities lead to the release of Cd into the hypergenic ecosystem, resulting in Cd pollution. The concentrations of Cd vary greatly from one type to another type of rocks in the mining district. In the host rock, Cd concentrations range from 50×10^-6 to 650×10^-6 with an average of 310×10^-6. In primary ores, Cd concentrations range from 14×10^-6 to 2800×10^-6 with an average of 767×10^-6. However, in oxidized ores, Cd concentrations are highest, varying within the range of 110×10^-6 to 8200×10^-6 , averaging 1661×10^-6. It is shown that the oxidized ores are the main carder and environmental source of Cd. Leaching test showed that Pb/Zn ores are easy to oxidize and thereafter release Cd and other harmful elements. These leached elements in the leachate may be precipitated rapidly in the order of Zn〉Pb〉Cd. As for the concentration distribution of Cd in the Bijiang River, it is estimated to be 15.7 μg/L Cd in water, 49.3 mg/L in suspended substances, and 203.7 mg/L in sediments. The average value of Cd in soil from the polluted area is 83.0 mg/kg. Natural weathering of Cd-rich rocks and minerals imposes a potential environmental risk on the aquatic ecosystem of the Bijiang catchment.     

松辽平原区荒漠化形成与发展的地质基础

利用卫星数据,结合实地地质调查、光释光（Optically Stimulated Luminecence, OSL）测年及孢粉数据,从地层、新构造和沉积环境等角度阐述了松辽平原晚更新世晚期湖积环境的形成与变化,提出了松辽平原晚更新世晚期湖积环境或湖积物质是区内荒漠化形成与发展的地质基础。     

基于小波变换的全色和多光谱遥感图像融合

基于多分辨率小波变换,针对高分辨率全色图像和多光谱图像的融合,提出了一种基于方向可调滤波器的区域能量测量的小波变换融合算法.将此方法与HIS和传统小波的融合方法比较,结果表明,该方法在保留多光谱图像光谱信息的同时,能够更好地保留高分辨率图像的空间信息,融合效果有较大改善.     

区域似大地水准面确定的最小二乘支持向量机方法

支持向量机(SVM)是近年来发展起来的机器学习的新方法,它较好地解决小样本、非线性、高维数、局部极小点等实际问题.文中研究支持向量机的拓展算法--最小二乘支持向量机(LSSVM),并将其应用于确定大面积复杂似大地水准面.通过工程实例并与神经网络模型和二次曲面多项式拟合模型相比较,验证确定区域似大地水准面的LSSVM方法的有效性.     

Study on Recovering the Earth＇s Potential Field Based on GOCE Gradiometry

Given the second radial derivative Vrr（P） ｜δs of the Earth＇s gravitational potential V（P） on the surface δS corresponding to the satellite altitude, by using the fictitious compress recovery method, a fictitious regular harmonic field rrVrr（P）^＊ and a fictitious second radial gradient field V：（P） in the domain outside an inner sphere Ki can be determined, which coincides with the real field V（P） in the domain outside the Earth. Vrr^＊（P）could be further expressed as a uniformly convergent expansion series in the domain outside the inner sphere, because rrV（P）^＊ could be expressed as a uniformly convergent spherical harmonic expansion series due to its regularity and harmony in that domain. In another aspect, the fictitious field V^＊（P） defined in the domain outside the inner sphere, which coincides with the real field V（P） in the domain outside the Earth, could be also expressed as a spherical harmonic expansion series. Then, the harmonic coefficients contained in the series expressing V^＊（P） can be determined, and consequently the real field V（P） is recovered. Preliminary simulation calculations show that the second radial gradient field Vrr（P） could be recovered based only on the second radial derivative V（P）｜δs given on the satellite boundary. Concerning the final recovery of the potential field V（P） based only on the boundary value Vrr （P）｜δs, the simulation tests are still in process.