长江中下游中酸性侵入岩中的黑云母及其地质意义

本区中酸性侵入岩中的黑云母属镁铁系列。有铁叶云母、铁黑云母、铁质黑云母及镁质黑云母四种类型。Ⅰ型长江系列为镁质黑云母;江南系列为铁质黑云母。A型苏州式为铁叶云母和铁黑云母;大龙山式则为镁黑云母—金云母。黑云母的成分与其生成条件有关,在榍石—磁铁矿—石英—角闪石矿物组合中,黑云母含铁度高者(ΣFe/ΣFe+Mg>0.5)其氧逸度随温度上升而增高,形成温度低则压力高,岩体侵位深。含铁度低者(ΣFe/ΣFe十Mg<0.5)氧逸度随温度上升而降低,形成温度高则压力低,岩体侵位浅。各类云母均有自己的成矿专属性。     

清洁生产-松花江有机污染防治的重要途径

论述了在松花江流域企业中实施清洁生产的重要性和必要性,阐明了实施清洁生产是松花江有机污染防治的重要途径;提出了流域实施清洁生产工作重点.     

中小城市空气质量预报试验与问题研究

当前中国大气污染形势严峻,迫切需要开展环境空气质量预报预警业务工作。为调研国内中小城市开展空气质量预报的基础条件和业务需求,促进全国城市空气质量业务体系建设,中国环境监测总站组织8个典型中小城市,利用基于数值预报基础的统计模式预报系统开展了空气质量预报实验工作。在此基础上,针对开展全国预报业务体系建设所需的中小城市预报方法、基础条件、人员技术水平等方面进行专项调研,并对国内中小城市开展空气质量预报能力建设和业务工作面临的问题、困难提出了建议和参考对策。     

塔里木河中下游的整治与基础设施建设

塔里木河中下游地区是南疆社会经济发展较快的地区，人类活动对塔河干流区生境干扰，在该区域表现得也较为突出，严重地影响了整个南疆地区的发展。在西部大开发中，塔河中下游的整治是基础建设的前提和保证，基础设施建设必须与塔河中下游整治结合起来。     

太湖流域1991年洪涝灾害的原因分析与治理对策建议

本文扼要叙述了太湖流域1991年的灾害概况,从气候、地形和水系特征等方面说明太湖流域存在发生洪涝灾害的自然条件,指出人为不恰当活动是加剧洪涝灾害的不可忽视的原因.最后对治理对策提出了六点建议.     

松花江嫩江流域洪涝发生与流域内降水的关系

利用松花江、嫩江流域１９５１￣１９９５年期间的气象和水文资料,采用相关分析、经验正交分析等方法,讨论了该流域洪涝发生的规律及其与流域内降水分布的关系。文章指出,江流域的水闰变化有明显的阶段性,且具有全流域一致的特性,目前正处在８０年代以来洪涝较严重的阶段;嫩江流域降水异常偏多对松花江洪涝的影响比第二松花江的作用要大;１９９８年夏季,松花江、嫩江流域出现超历史纪录特大洪水的关键原因是嫩江流域６￣８月     

A multilevel analysis of private-vehicle evacuation clearance times along the US Gulf Coast

This study uses multilevel regression analysis to examine the effect of social characteristics and the built environment on clearance time under an evacuation scenario. The primary unit of analysis is the US Census tract (N?=?1660), nested within 31 incorporated places spanning five US states. The dependent variable is an estimate of clearance time in hours derived using network analysis techniques within a geographic information system. We find that tracts with a more peripheral location, more female residents, a higher proportion of Hispanic residents, and higher median household incomes are associated with higher clearance times, on average. Our research suggests the relationship between suburbanization and clearance time is complex and evolving, mediated by past investments in the built environment and shifting social conditions. In addition to facilitating the evacuation of areas with low access to personal vehicles, urban planners and emergency management officials should also consider how the degree of connectivity in the street network impacts congestion and clearance time.     

基于Copula模型的降雨量与土壤饱和度的模拟研究

采用两步法,针对云南东川蒋家沟流域的降雨量与土壤饱和度,建立了边缘为皮尔逊Ⅲ型的Clayton Copula模型,分析了降雨量和土壤饱和度之间相关结构,以及两变量重现期,模拟了流域内土壤饱和度的变化情况。实例表明所构造的Clayton Copula模型能比较好地模拟出流域内土壤饱和度在降雨情况下逐日变化情况,有助于进一步认识降水对土壤饱和度的作用过程,并为分析泥石流灾害的发生提供了一种新思路。     

大型河谷场地地震动特性研究

采用有限差分方法,通过算例研究了大型河谷场地地震动特性分析中的人工边界的选取方法,对比分析了不同人工边界的选取对数值模拟结果的影响,确定了散射场地震反应分析输入边界的地震动输入方法,认为在进行有限差分动力计算时,模型两侧施加自由场边界的模拟效果要优于两侧施加粘性边界的模拟效果;同时,对FLAC计算软件进行二次开发,对2个地形差异较大的河谷场地,采用线性和非线性摩尔-库仑模型进行了地震反应对比分析,研究了河谷场地地震动幅值和频谱特性随地形变化的规律。模拟数据表明,河谷场地谷底处地震动基本无放大作用,地势凸起处放大作用则较为明显;当考虑土体非线性时,随着地震动强度的增加,放大作用逐渐减小;谱分析结果表明,地势凸起处受高频地震动的影响显著,而地势平坦的谷底则受低频地震动的影响显著。     

Seasonal Variations and Chemical Forms of Heavy Metals in Soils and Dusts from the Satellite Cities of Seoul, Korea

This research investigated heavy metal pollution of soils and dusts in two representative satellite cities of Seoul, Korea and studied the seasonal variations in metal concentrations through the rainy season and the chemical forms of metals using a sequential extraction analysis. The metal dispersion pattern was illustrated to match with urban structure. Soil and dust samples were collected from the cities of Uijeongbu and Koyang, which are the northern and northwestern satellite cities of Seoul (the capital), before and after rainy season. Concentrations of Cu, Pb and Zn were higher than those of the world averages for soils, and their levels decreased after rain, particularly in highly contaminated samples. Relatively high pH values were found in roadside soils, but no seasonal variation was found after the rainy season. The three metals (Cu, Pb and Zn) in soils and dusts were associated with various chemical fractions of soils and dusts as distinguished by the sequential extraction scheme, and a strong similarity of metal association between soils and dusts was found, which indicates that airborne dust may be a principle source of soil contamination. Copper is uniformly distributed, and Pb is largely associated with the reducible phase. There is an appreciable proportion of total Zn in the exchangeable/water-acid soluble fraction. After the rainy season, the most soluble fractions in soils and dusts were leached away. In terms of mobility and bioavailability of metals in soils and dusts, the order Zn >> Cu > Pb is suggested. Geographical variations of total metals corresponded well with urbanised areas of cities, especially the industrial complex and major motorways.