An approach to studying heavy metal pollution caused by modern city development in Nanjing, China   总被引：8，自引：0，他引：8  

Hui Zhang  Dongsheng Ma  Qinglin Xie  Xiaoling Chen 《Environmental Geology》1999,38(3):223-228

 Nanjing is currently one of the fastest developing regions in terms of construction and economy in China. Heavy metal pollution is becoming more serious with the expansion of production and life scales. Four environmental units (highway, refinery, rubbish dumps associated with human daily life, and shoal of the Yangtse River) were selected from the region according to the geneses of the pollution to study and evaluate the distribution and mechanism of the contamination, the speciations of the polluting elements, and the geneses of the pollution in the soils and sediments. The purposes of the study are to understand generally the current situation and the cause of the pollution, and to provide a scientific basis to prevent and solve the pollution problem. At the same time, it would be helpful to probe the effective way of studying heavy metal pollution resulting from the development of modern cities and to accumulate data. It is indicated by the study that the heavy metals contained in the soil of the environmental unit of the highway are Pb, Co and Cr; in the soil of the refinery Cr, V, Pb, Ni, and Co; in the soil of the rubbish plot Co, Cu, and Sb; in the sediments of the shoal Pb, Co, Cu, and Ni. Fe-Mn oxide is given the first place to the speciations in polluting heavy metals transmitted by air. Carbonate is more in speciations of polluting heavy metals transmitted by water than in speciations of the metals transmitted by air. In the ten elements studied, Pb is most directly poisonous to the plants in the region; Co and Cu are the next, and Ni is the least. Heavy metal pollution has been occurring in the soils and sediments of the region and the situation will worsen if some effective measures are not taken. Received: 18 October 1997 · Accepted: 3 February 1998  相似文献   

Analysis of the Dynamic Performance of an Underground Excavation in Jointed Rock under Repeated Seismic Loading   总被引：5，自引：0，他引：5  

M. Ma  B.H. Brady 《Geotechnical and Geological Engineering》1999,17(1):1-20

Results from field observations of dynamic behaviour of an underground excavation have been compared with numerical studies of the rock deformation history. The field behaviour shows progressive accumulation of rock displacement and excavation deformation under successive episodes of dynamic loading. It is possible to reproduce the modes of rock response quite well using a Distinct Element model of the rock mass, but the way displacements develop is dependent on the joint model used in the analysis. It is suggested that, in rock masses subject to repeated dynamic loading, excavation design may need to take account of the prospect of repeated episodes of transient loading at the excavation site.  相似文献   

黑龙江省塔河绿林林场一带兴华渡口群岩石地球化学特征     

表尚虎  李仰春  何晓华  周兴福  马丽玲 《地质通报》1999,(1):88

黑龙江省塔河西北绿林林场一带原划分的兴华渡口群的岩石地球化学成分可与太古宙绿岩带对比,该区的兴华渡口群为低级地体（火山沉积盆地）,ＳｍＮｄ模式年龄及单阶段演化年龄为（１２５２±２８～１４６３±２０）Ｍａ。  相似文献   

利用干涉图确定成像质量     

吴新民  马轩文 《测绘学院学报》1999,(1)

从像质的概念出发,导出了像质评定的简单公式。在干涉图的每个选定点上测量条纹间的间隔和角度来计算几何光线的斜率误差,然后把这些角度误差画在一张图纸上用以表示几何点扩散函数的角度大小,可以方便而简洁地评定成像质量,避免了复杂的计算。  相似文献   

局部地形校正的精密算法     

马世峰  边少锋  杨林春 《测绘学院学报》1999,(3)

对局部地形校正中的中央区奇异积分部分进行非奇变换,使用Simpson公式和Cotes公式推导出两种中央区的数值计算方法。试算结果表明,新方法可有效地提高地形校正的精度。  相似文献   

原子Na的电子碰撞电离     

马轩文  王秀泽  王荣 《测绘学院学报》1999,(4)

使用Ｒ矩阵方法, 在扭曲波和库仑玻恩近似下计算了入射电子能量为２０ ｅＶ、５０ｅＶ 及１００ ｅＶ 原子Ｎａ 的电子碰撞电离截面, 并详细给出了入射电子能量为５０ ｅＶ 时的能量微分截面及分波能量微分截面。计算结果揭示了明显的Ｒｙｄｅｒｇ 系列共振, 并使用量子亏损理论对结果进行分析和讨论, 展示了Ｒｙｄｅｒｇ 系列共振的丰富内容。  相似文献   

黄山旅游气候指南   总被引：20，自引：0，他引：20  

杨贤为  邹旭恺  马天健  王效瑞 《气象》1999,25(11):50-54

通过对黄山地区气候特征的概括,对各具特色的气象景观及其出现季节,时段的分析和计算,为有关部门合理安排旅游计划。为广大游客根据自身具体情况选择理想的旅游季节提供了指导性的参考意见。  相似文献   

盛夏数值预报模式对副高预报性能检验及其释用   总被引：1，自引：0，他引：1  

马德贞毛恒青  鲍媛媛林玉成 《气象》1999

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三峡地区气候Z-R关系     

张家国  王佐兵  力梅  杨洪平  万玉发  蔡宏 《气象》1999,25(3):44-48

在三峡地区降水条件气候均匀区域划分的基础上,用Ａｔｌａｓ一阶矩概率匹配法,分别在每一个区域建立了对流型、雷雨混合型、阵雨混合型３种雨型随测距变化的气候Ｚ－Ｒ关系。这些关系能综合订正由波束平均作用、雨区对电磁波的衰减等因素所造成的雷达测量降水的误差  相似文献   

用单多卜勒雷达确定中尺度气旋环流中心及最大风速半径     

马翠平  张培昌 《南京气象学院学报》1999,22(3):403-407

首先给出具有 Ｒａｎｋｉｎｅ 模式的中尺度气旋的模拟多卜勒径向速度图,然后利用多卜勒雷达观测的径向速度与实际气流间的几何关系,提出一种确定近似轴对称的中尺度气旋中心及最大风速半径的方法。  相似文献