基于SWAT模型的江西八里湖流域氮磷污染负荷研究

基于SWAT模型, 通过社会调查和统计数据获取模型所需的空间数据及污染源输入数据, 构建江西八里湖流域的氮磷负荷模拟模型, 并利用当地 2010—2014年的气象、径流和水质观测资料, 对模型进行率定和验证。依据该模型, 分别在时间和空间上对研究流域的氮磷污染物分布进行模拟。结果表明: 流域氮磷污染主要来自城镇生活源、农田施肥和畜禽养殖, 工业源最少; 氮磷负荷主要集中在汛期(5—9月), 占全年的55%, 汛期污染负荷主要受农村生活和农业施肥的面源影响, 随着降水增大等因素导致冲刷作用增强, 径流中总氮和总磷的负荷也随之增大。氮磷等营养物负荷主要分布在流域内人口密集的九江县、浔阳区和庐山区, 与对应区域大量城镇生活污水的排放相关。     

基于输出系数法的苕溪流域面源污染负荷估算

位于浙江北部的苕溪流域是浙江八大水系之一,具有典型的平原水网特征,地势平坦,水系复杂,河网密布。由于人口密集,工农业生产强度大,导致经济环境之间的矛盾日益严重,为探究苕溪流域主要污染源总氮总磷污染负荷现状,采用输出系数法对苕溪流域氮磷污染负荷进行核算,从农村生活、畜禽养殖、农业种植、水产养殖四大来源进行了统计。结果表明:在总氮污染来源中,畜禽养殖是最大的污染来源,占总贡献量的27%,其次是种植业,占比达25%,在总磷的污染负荷来源中,畜禽养殖是最主要污染来源,比例达49%。总体来看,苕溪流域面源污染氮磷来源主要为:畜禽养殖农村生活污水种植业水产养殖,流域内水环境生态安全与人为因素相关。     

西北地区城镇生活污水排放规律探究——以兰州市为例

采用抽样调查法,对典型城镇兰州市不同生活区域污水管网处理前端水量、水质进行检测分析,对生活污水产污系数进行核算.结果表明,城市生活污水排放与人居生活习惯及人群活动频繁度密切相关,不同生活区域污水排放量存在差异;生活污水中主要污染因子为CODCr、BOD5、氨氮、总氮、总磷、动植物油、石油类,其中CODCr、BOD5、氨氮、总氮、总磷处理前浓度较高,动植物油、石油类处理前浓度较低;不同城镇生活污水产污系数存在明显差异,县级城镇产污系数较高,乡镇产污系数较低.     

基于环境容量的入湖污染负荷削减分析

水环境污染是困扰城市发展和影响人居生活的重要因子。为探索研究河湖水环境改善措施,尤其是研究与人居环境密切相关的城市内湖水环境提升,以武汉市南湖为例,开展了典型城市公园型湖泊的水质提升问题。通过对南湖汇水范围内污染物来源的进行精细化定量解析,结果结果表明南湖入湖总氮(TN)和总磷(TP)负荷分别为835.6 t/a和92.56 t/a;污染负荷空间分布有三个典型峰值区域,其面积仅占汇水范围的10.7%,而其TN产污负荷占25.18%,总磷产污负荷占23.97%。采用狄龙模型计算得出南湖水域TN环境容量为315.2 t/a,TP环境容量为21.01 t/a。在完成城镇生活污水和底泥释放中60%TN去除和75%TP去除的基础上,同时地表径流中TN控制率达到67%、TP控制率达到87%,即TN和TP排放量控制在环境容量限值以内,可使TN浓度达到1.5 mg/L,TP浓度达到0.1 mg/L,南湖水质总体达到地表水Ⅳ类要求。基于环境容量分析的入湖污染物来源定量解析,以及进一步对汇水范围内污染负荷的空间分析,可为河湖水环境污染治理措施的合理安排提供科学依据。     

南水北调中线陕西水源区非点源总氮负荷估算

目的 估算南水北调中线陕西水源区非点源总氮污染负荷并分析其影响.方法 利用输出系数法计算水源区非点源,TN污染负荷.结果 水源区陕西汉丹江流域非点源TN约为8.2×104t/a,主要来自汉江流域.结论 非点源污染是影响陕西水源区水环境质量的一个重要方面,陕西水源区非点源污染的控制管理已刻不容缓.     

基于SWAT模型的农业施肥对梅江流域营养盐产出变化的影响分析

以梅江流域为研究区域,基于SWAT模型构建适用于该流域的氮磷污染负荷模型,模拟分析了农业施肥影响下的流域内氮、磷营养盐产出的时空分布变化特征,为该流域营养盐污染控制和综合治理提供有益参考.结果表明:1)研究区氮、磷营养盐产出的增加与农业化肥的施用有关,在时间变化上,2011年流域内总氮和总磷的产出分别增长了99.33 mg/L和17.64 mg/L,总氮、总磷负荷产出的增加主要集中在4—8月,分别占全年总产出的87.3％和68.5％;2)在空间分布上,总氮、总磷污染负荷变化的空间分布特征基本一致,均集中在研究区的中部和北部.     

伊犁河流域水质量评价及防治对策研究

分析和评价了伊犁河流域各断面的水质量,并提出流域控制断面水污染防治对策.根据国家水质量评价标准,伊犁河流域背景断面水质量无污染,控制断面水质量中度污染,其中控制断面水质量污染是由工业废水和生活污水所致.建议通过制定伊犁河流域控制断面水污染负荷,限制控制断面污水排放量,实现伊犁河流域水质量安全.     

变化情景下的漳卫南运河流域水量水质模拟

漳卫南运河流域是我国一个水资源短缺、水质恶化的典型流域.本文应用SWAT模型,结合设置的9种变化情景(包括降雨量、灌溉量、点源排放量、面源污染量),模拟了流域内主要站点(辛集、元村、合河、庆云、四女寺、临清、观台和淇门站)的径流量、总氮、总磷质量以及流域蒸散发在不同情景下的响应.结果表明:降雨量增加25%,将增加径流量147%、总氮50.2%、总磷83.3%、蒸散发8%;灌溉量减少10%,将增加径流量约4%,降低蒸散发3%;点源污染按达标排放将减少总氮24%、总磷8%;按环境容量排放将减少总氮15%、总磷9%;按排放量消减15%,将减少总氮7%、总磷15%;面源污染量减少10%,将减少总氮4%、总磷2%.为了增加入海流量、减少人海污染量,最佳情景组合(即降雨量维持现状、灌溉用水量减少20%、点源按达标排放、面源污染量减少20%),将增加径流量43.6%,总氮和总磷含量减少29.9%和14.2%.这些结论可为漳卫南运河流域的水量配置和水质污染控制措施提供一定的科学依据.     

太湖流域土地利用方式演变及其对水体氮磷负荷的影响

为研究太湖流域的水环境现状和污染特征,通过分析研究区氮磷负荷变化对土地利用方式的响应,对太湖流域各土地利用方式与氮磷负荷特征的相关性及其影响因素进行研究.结果表明:1980年至2010年,太湖流域耕地面积占比由63.89%降到47.02%;而建设用地面积占比由9.70%增加到25.16%;林地面积微缩小;水域面积微提升;草地和未利用地面积不大且变化可忽略.各土地利用状态指数D_i大小依次为:建筑用地耕地未利用地水域林地草地.太湖流域由于土地利用方式的转变带来的氮和磷排放对水体总氮(TN)负荷和总磷(TP)负荷的贡献均呈逐年递增趋势. TN在1980年3.71万t的基础上,2010年排放量增加了67.51%. TP负荷从0.33万t增加到了2010年的0.85万t.     

浑河流域水功能区达标性分析

目的分析浑河流域沈抚新城下游河段的污染物流经水体的水质状况,解决沈抚新城面临的水环境问题,确保当地水环境安全.方法选取COD和氨氮为污染因子,计算浑河东陵大桥至长青桥河段的水环境容量.利用QUAL2K软件模拟污水经杨官河和白沙河进入浑河后,研究区域的污染物质量浓度变化.结果计算出东陵大桥至长青桥河段的水环境容量为COD 18.23 t/d,氨氮2.54 t/d.污水集中处理后经白沙河排放,对下游浑河水质影响较小,能够满足水功能区划;合理分配水量,使污水经白沙河和杨官河分别排入浑河时,下游水质符合水功能区要求;污水全部通过杨官河排放,下游水质不能满足水功能区划.结论从而确定沈抚新城的污染物排放量、污水处理厂出水水质及污水排放位置.为浑河水资源的开发利用和保护管理提供科学依据,进而实现水资源的科学合理可持续利用.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.