Spatial and temporal trend of sewage pollution indicated by coprostanol in Macao Estuary,southern China

Bottom sediments and a ²¹⁰Pb dated sedimentary core in Macao Estuary were quantitatively analyzed with GC-MS for coprostanol and other sterols. Higher coprostanol concentrations were detected at Port Interior and Lower Qianshan River, indicative of serious sewage pollution from densely populated Macao Island and Zhuhai City. However, very low concentrations of coprostanol were detected around Coloane Island as well as Port Exterior and Maliuzhou River except sites adjacent sewage outlets. Coprostanol pollution in Macao Estuary originates mainly from locally direct discharge of untreated wastewater. The concentrations of coprostanol in ZJ-9 were mainly in range of 150–280 ng/g with an average of 210 ng/g for more than 20 years from early 1970s to early 1990s. However, it increased obviously since 1993, and reached the highest in 1995–1996. However, a sharp decrease of coprostanol concentration from 470 to 31 ng/g after 1996 was observed corresponding to the first wastewater treatment plant in Taipa Island going into action.     

城市外来低收入移民安置与自下而上城市化发展

中国在由二元经济社会跨入现代经济社会的过程中 ,众多的农村人口向城市流动和转移 ,已经给中国社会和城市发展带来严重的影响。通过对广州市和东莞市两市三个层次的一般抽样调查和 5 0个镇村的重点调查和分析 ,以城市外来低收入移民为研究和安置的对象 ,提出了适合中国情况的自下而上的开发性移民自助安置模式 ;并分析了自助安置模式对城市发展的影响 ,提出了一种在城市地域发生的自下而上的城市化理论发展假设。     

论中国东部大型盆地区及邻区地质-地球物理复合尺度解析

作为对中国东部陆缘地带大型盆地区及邻区地质－地球物理综合研究的部分结果,本文的基本认识：（1）穿过松辽盆地的1孙吴－双辽断裂可能是东倾伯低角度壳内断裂;（2）松辽盆地和渤海湾盆地可能属于“混合型裂谷盆地”;（3）东海盆地台北坳陷处在多期次张性应力场环境中,使在其西部附近产生张性正断层系;（4）欧亚大陆东部新生代区域构造运动总体处于右旋走滑拉张环境,其动力因素包括板块运动和地幔物质运动;（5）研究区莫霍面具有较为复杂的变化;（6）复合尺度研究方法是地质－地球物理综合分析的必要手段。     

流域地理景观的GIS数据三维可视化

应用以"GIS"为核心的空间信息技术,是开展"数字流域"工程建设自然和最佳的选择。结合"清江流域水文水情与洪水演进仿真系统"的具体研制,分析流域地理数据特点及传统GIS在"数字流域"建设中的优缺点,在应用传统GIS二维方式展示形式管理和预处理先期各类基础流域地理空间数据及其相应属性数据的基础上,为满足仿真系统系列三维可视化要求,建立面向流域空间实体对象的数据模型,定义流域地理空间对象数据结构,将流域地理常规的GIS数据以三维形式展示,在实际的系统开发过程中,取得较好的三维可视化效果,并可满足"数字清江"建设各阶段综合处理、分析、评价、决策以及可视化等方面的需求。     

"三联式"资源定量预测与评价--数字找矿理论与实践探讨

随着信息技术的发展,矿产勘查已步入数字化,定量化研究的新阶段。“三联式”成矿预测及资源评价途径正是“数字找矿”的创新探索。“三联式”成矿预测以地质异常分析为基础,以成矿多样性分析与矿床谱系研究为指导,将地质异常,成矿多样性及矿床谱系三方面定量化研究紧密结合形成矿产预测及定量评价的有机切入点,是实现全面数字找矿的必由之路,也是矿产勘查评价领域应用信息技术的基础和前提。     

城市虚拟现实研究初探

虚拟城市是 3维城市地理信息系统的前沿领域 ,该文对在微机上如何建立虚拟城市作了初步探讨 ,把建立虚拟城市的方法分为 3维真实场景建模、海量数据环境下的场景漫游以及确定任意时刻声音文件的调入时机三个部分。重点介绍了控制三维场景漫游、自适应层次细节模型、简单碰撞检测的实现方法 ,并提出了采用泰森模型调用声音文件的新思路。最后给出在VC 开发环境下用OpenGL建立虚拟城市的应用实例。     

A bed‐load transport model for rough turbulent open‐channel flows on plane beds

Data from flume studies are used to develop a model for predicting bed‐load transport rates in rough turbulent two‐dimensional open‐channel flows moving well sorted non‐cohesive sediments over plane mobile beds. The object is not to predict transport rates in natural channel flows but rather to provide a standard against which measured bed‐load transport rates influenced by factors such as bed forms, bed armouring, or limited sediment availability may be compared in order to assess the impact of these factors on bed‐load transport rates. The model is based on a revised version of Bagnold's basic energy equation i_bs_b = e_bω, where i_b is the immersed bed‐load transport rate, ω is flow power per unit area, e_b is the efficiency coefficient, and s_b is the stress coefficient defined as the ratio of the tangential bed shear stress caused by grain collisions and fluid drag to the immersed weight of the bed load. Expressions are developed for s_b and e_b in terms of G, a normalized measure of sediment transport stage, and these expressions are substituted into the revised energy equation to obtain the bed‐load transport equation i_b = ω G ^3·4. This equation applies regardless of the mode of bed‐load transport (i.e. saltation or sheet flow) and reduces to i_b = ω where G approaches 1 in the sheet‐flow regime. That i_b = ω does not mean that all the available power is dissipated in transporting the bed load. Rather, it reflects the fact that i_b is a transport rate that must be multiplied by s_b to become a work rate before it can be compared with ω. It follows that the proportion of ω that is dissipated in the transport of bed load is i_bs_b/ω, which is approximately 0·6 when i_b = ω. It is suggested that this remarkably high transport efficiency is achieved in sheet flow (1) because the ratio of grain‐to‐grain to grain‐to‐bed collisions increases with bed shear stress, and (2) because on average much more momentum is lost in a grain‐to‐bed collision than in a grain‐to‐grain one. Copyright © 2006 John Wiley & Sons, Ltd.     

A Statistical Investigation of the Earthquake Predictions Using LURR

In terms of the spatial scanning of LURR (Load-Unload Response Ratio), we have been predicting the seismic tendency within the next year for the mainland of China from 1995 to 2003. In order to make the quantitative retrospective assessment of LURR method, we compare the results with Poisson null hypothesis. The results show that the prediction by LURR method is much better than Poisson hypothesis.     

Mineralogical and geochemical study of a newly discovered mafic granulite, northwest China: Implications for tectonic evolution of the Altay Orogenic Belt

Abstract A mafic granulite body was newly discovered in the Altay Orogenic Belt, northwest China. The rocks comprise a suite of coarse‐grained and fine‐grained granulites. Orthopyroxenes (hypersthenes) in the rocks have high X_Mg and low Al₂O₃ contents, whereas clinopyroxenes have low TiO₂ and Al₂O₃ contents. Amphiboles and biotites have a high Mg/(Mg + Fe²⁺) ratio and low contents of F and Cl. The peak metamorphic pressure–temperature (P–T) conditions are estimated as 750–780°C and 6–7 kbar, and retrograde P–T conditions are in the range of 590–620°C and 2.3–3.7 kbar, indicating significant decompression. Metamorphic reactions and P–T estimates define a clockwise P–T path. Geochemically, the rocks are high in Mg/(Mg + Fe) and Al₂O₃, depleted in U, Th, K and Rb, and characterized by light rare earth element enrichment and a weak positive Eu anomaly. The Altay mafic granulite shows depleted Nb, P and Ti contents in the mid‐oceanic ridge basalt normalized spider diagram. The geochemical characteristics suggest that the protolith of the Altay mafic granulite was calc‐alkaline basalt and andesite with an island‐arc affinity. The rock has a high ¹⁴³Nd/¹⁴⁴Nd ratio with ?Nd(0) > 0, indicating derivation from a mantle‐depleted source. In the present study, a two‐stage model for the evolution of the Altay mafic granulite is proposed: an early stage in which calc‐alkaline basalt and andesite with island‐arc affinity were subducted into a deeper level of the crust and subjected to granulite‐facies metamorphism generating the mafic granulite, followed by the later stage exhumation of the system into the upper crust by the late Paleozoic thrusting.     

西藏普兰石炭纪地层的厘定及其地质意义

通过区域地质调查,利用确定上覆、下伏地层时代与区域地层对比方法,结合邻区古生物年代特征,对西藏普兰北喜马拉雅分区下石炭统进行了厘定。普兰地区早石炭世受沉积环境与物质供应量等因素影响,岩性、岩石组合特征与邻区略有差异,其下部以变质粉晶灰岩为主夹变质泥质粉砂岩,厘定为亚里组;上部以变质细粒砂岩为主夹变质粉晶灰岩,厘定为纳兴组。