采用DPIV技术研究浅水平板岛屿尾流

人们对于尾流的研究大都针对绕流体在展向非常长的情形,但是在天然环境和水利工程中出现的多为水深相对很浅的流动。由于槽底和自由水面的限制,浅水域中的尾流有着与深水尾流不同的流动规律。采用数字粒子图像测速(DPIV)技术,在长30m、宽3.5m、高1m的水槽中比较系统地量测了浅水中绕平板岛屿的尾流区流场。分析了大尺度旋涡的运动规律,得到了尾流流动形式随尾流稳定性参数的变化规律。目前如此大尺度浅水岛屿尾流的定量实验研究并不多见。     

昌马水库右岸山体稳定性研究

昌马水库导流排砂洞塌方导致右岸山体发生松动 ,本文在大量地质资料的基础上 ,对右岸岩体裂隙网络进行模拟 ,同时 ,采用极限分析能量法和有限元数值模拟方法等对右岸山体的稳定性进行分析研究 ,并提出相应的加固方案。     

青铜文物腐蚀过程中的次生矿物

产于不同环境不同地方的青铜文物经矿相显微镜观察、电子探针成分分析和X射线衍射研究表明，在青铜文物腐蚀层中观察到次生矿物——赤铜矿、孔雀石、蓝铜矿、白铅矿和锡石。由上述矿物组成的腐蚀层在青铜器表面形成保护层。腐蚀层细分为红色赤铜矿层、绿色碳酸盐矿物层和黄色锡石层组成，其厚度小于1mm。青铜合金在潮湿条件下的腐蚀比在干旱条件下要严重，另外青铜合金是适用于作高放废物地质处置系统中的废物罐的候选材质。     

西天山艾肯达坂组火山岩系同位素定年及其构造意义

西天山艾肯达坂地区较好发育了艾肯达坂纽红色陆相火山岩建造．它不整合在下石炭统大哈拉军山组之上,未经变形和变质，属于陆陆碰撞晚期的橄榄安粗岩系，其年龄确定是厘定从碰撞造山向陆内构造演化的关键。因此,通过16件新获得的钾氩年龄测值，确定艾肯达坂组火山岩系形成在260Ma～270Ma之间，属早二叠世，而不是过去认为的石炭纪；西天山的陆陆碰撞应在二叠纪末结束,此后进入陆内造山阶段。     

水布垭面板堆石坝的三维弹塑性数值分析研究

在建的清江水布垭面板堆石坝高达233 m,是目前同类坝型中最高的.采用MSC.Marc非线性有限元程序,发展了三维子模型法,对该坝进行了三维弹塑性有限元仿真分析,模拟了面板的分缝、坝体材料分区、填筑及蓄水过程,采用双屈服面弹塑性模型模拟堆石体的变形特征.根据数值分析的结果,对坝体和面板的应力变形分布规律进行了探讨.     

长江三角洲主要城市产业结构转换的综合评价

文章在对地区产业结构转换影响因素系统分析的基础上，采用定量分析方法，对长江三角洲15个主要城市的产业结构转换能力、产业转换速度、产业转换方向以及它们之间的关系进行探讨。研究表明：长江三角洲主要城市产业结构转换能力的区域差异明显，产业结构转换能力与区域经济发展所处阶段有很大的关系；产业结构转换能力、速度与经济发展水平呈正相关。     

DLG数据采集中的自动接边实现

分析了实现自动接边中需要解决的基本问题，说明了DLG生产中不推荐使用曲线的理由，给出了接边程序的流程和关键算法。最后介绍了MAP系统中的自动接边功能。     

信息时代地图技术美的研究与实践

通过分析现代地图表现形式及存在的问题，探讨了信息时代地图制图技术美的含义和地图技术美的表现形式。并在技术美创新理念指导下，对利用计算机技术和图形图像处理技术来改进地图符号设计，提高地图表现力进行了一些理论探讨和技术尝试．同时也得到了一些有益的启示。     

Study of statistically correcting model CMAQ-MOS for forecasting regional air quality

Based on analysis of the air pollution observational data at 8 observation sites in Beijing including outer suburbs during the period from September 2004 to March 2005, this paper reveals synchronal and in-phase characteristics in the spatial and temporal variation of air pollutants on a city-proper scale at deferent sites; describes seasonal differences of the pollutant emission influence between the heating and non-heating periods, also significantly local differences of the pollutant emission influence between the urban district and outer suburbs, i.e. the spatial and temporal distribution of air pollutant is closely related with that of the pollutant emission intensity. This study shows that due to complexity of the spatial and temporal distribution of pollution emission sources, the new generation Community Multi-scale Air Quality (CMAQ) model developed by the EPA of USA produced forecasts, as other models did, with a systematic error of significantly lower than observations, albeit the model has better capability than previous models had in predicting the spatial distribution and variation tendency of multi-sort pollutants. The reason might be that the CMAQ adopts average amount of pollutant emission inventory, so that the model is difficult to objectively and finely describe the distribution and variation of pollution emission sources intensity on different spatial and temporal scales in the areas, in which the pollution is to be forecast. In order to correct the systematic prediction error resulting from the average pollutant emission inventory in CMAQ, this study proposes a new way of combining dynamics and statistics and establishes a statistically correcting model CMAQ-MOS for forecasts of regional air quality by utilizing the relationship of CMAQ outputs with corresponding observations, and tests the forecast capability. The investigation of experiments presents that CMAQ-MOS reduces the systematic errors of CMAQ because of the uncertainty of pollution emission inventory and improves the forecast level of air quality. Also this work employed a way of combining point and area forecasting, i.e. taking the products of CMAQ for a center site to forecast air pollution for other sites in vicinity with the scheme of model products "reanalysis" and average over the "area".     

Delayed geochemical hazard: Concept, digital model and case study

Delayed Geochemical Hazard (DGH briefly) presents the whole process of a kind of serious ecological and environmental hazard caused by sudden reactivation and sharp release of long-term accumulated pollutant from stable species to active ones in soil or sediment system due to the change of physical-chemical conditions (such as temperature, pH, Eh, moisture, the concentrations of organic matters, etc.) or the decrease of environment capacity. The characteristics of DGH are discussed. The process of a typical DGH can be expressed as a nonlinear polynomial. The points where the derivative functions of the first and second orders of the polynomial reach zero, minimum and maximum are keys for risk assessment and harzard pridication.The process and mechanism of the hazard is due to the transform of pollutant among different species principally. The concepts of "total releasable content of pollutant", TRCP, and "total concentration of active specie", TCAS, are necessarily defined to describe the mechanism of DGH. The possibility of the temporal and spatial propagation is discussed. Case study shows that there exists a transform mechanism of "gradual release" and "chain reaction" among the species of the exchangeable and the bounds to carbonate, iron and manganese oxides and organic matter, thus causing the delayed geochemical hazard.