南水北调中线工程核心水源区生态服务价值变化研究

南水北调中线工程已正式开始向北方输水,研究核心水源区的生态服务价值,可以为合理利用自然资源,保护生态环境提供重要的参考依据.该文确定了南水北调中线工程核心水源区范围,在分析生态服务价值评估方法的基础,评估了核心水源区生态服务价值,并从生态服务价值生态系统差异、区域差异、变化率以及空间分布等方面,分析了20多年来核心水源区生态服务价值的变化特征:全流域生态系统服务价值呈逐年递增的趋势;单位面积生态服务价值最高的子流域为官渡河流域、堵河流域与霍河流域,丹江流域与老灌河流域最低;老灌河流域、丹江流域、天河流域变化趋势最好,潭口河流域最差;中南部生态服务价值高于西南、东南部,北部最低.     

汉江上游不同气候情景下土地利用变化对径流的影响研究

研究了3种气候情景下,汉江上游丹江口以上流域土地利用变化对径流的影响.收集了1980、1995和2000年的土地利用和相应年代的气象数据,用SWAT模型进行汉江上游丹江口以上流域的水文模拟,利用模型进行了9种气候和土地利用组合情景的径流模拟,对比分析不同气候条件、不同土地利用下的径流变化.结果表明,土地利用变化对汉江上游流域产汇流特性有一定的影响.不同气候条件下,径流对土地利用变化的响应程度不同.其中相对干旱的20世纪90年代,径流对土地利用变化最敏感.相同的土地利用变化情况,在不同气候条件下,对径流的影响也不同.     

乐都区土地利用变化对生态系统服务价值影响研究

基于乐都区2009-2015年社会经济数据,运用土地利用变化模型、当量因子法及敏感性分析,结合乐都区实际情况,计算与分析乐都区土地利用变化特征、生态系统服务价值,对研究区各地类与地类面积变化、土地利用程度、气温、GDP的敏感性系数进行比较,进而得出土地利用对生态环境影响的量化结果。研究发现:土地利用程度变化量和变化率呈正值,乐都区土地利用在研究期内处于发展期;生态系统服务价值总体上呈增长趋势,气温和地类面积变化与各地类的生态系统服务价值敏感度系数较高;林地对乐都区生态系统服务价值起决定性作用。     

银川市2000—2020年土地利用时空变化特征及预测

为探究银川市土地利用的时空变化特征,基于2000、2010、2020年3期土地利用数据,通过土地利用变化、景观生态学和元胞自动机(cellular automata, CA)-Markov模型,定量研究了20年间银川市土地利用景观格局变化特征,并对土地利用变化进行模拟预测。结果表明:耕地、林地、水域和未利用土地面积减小,草地和城乡工矿居民用地面积增加,各土地利用类型之间转换较为强烈,土地利用变化结构的主体为草地和城乡工矿居民用地,土地利用程度不断加深但具有区域差异性特征;土地利用景观形状的复杂程度增加,城市空间不断扩张,整体景观都趋于平均,景观异质程度增强,景观向多样化方向发展趋势;CA-Markov模型能有效模拟银川市土地利用变化情况且具有较高精度,Kappa系数为0.828 5;2030年耕地、林地和未利用土地面积减少,草地和城乡工矿居民用地面积增加。人口数量与结构、国内生产总值(gross domestic product, GDP)、经济增长以及区域宏观政策是研究区各类土地利用类型变化的主要驱动因素。     

南水北调中线水源区土地的利用生态安全分析——以陕西省为例

土地利用变化对流域水资源动态具有深刻的影响,本文分析了南水北调工程建立前后水源区土地利用变化的时空分异规律,从而为科学地组织人类有序活动、调整和优化土地利用格局,以确保流域生态安全提供了理论基础.研究结果显示:1999~2009年研究区域土地利用生态安全状况呈先下降后逐渐回升好转最后又下降的趋势,2005年和2008年是两个转折点,土地利用的生态安全状态处于风险型和恶化型之间.     

草海湿地区域土地利用/覆被变化与预测研究

针对草海湿地区域典型性、特殊性,以1990、2000和2010年三期遥感影像为数据源,综合运用3S技术方法,从时间和空间两方面对研究区土地利用/覆被变化进行分析,继而利用MARKOV和CA-MARKOV模型预测研究区2020年土地利用情况.结果表明:草海湿地区域林地面积最大,耕地、草地面积变化较大,水域和建设用地的变化幅度和变化率明显且持续增加;从土地利用程度综合指数、变化量和变化率来看,土地利用集约化程度提高,土地利用正处于发展时期;从空间变化来看,1990-2000年土地利用/覆被类型间转化不大,2000—2010年转化较为复杂.通过对2020年预测分析结果可知,随着城镇化进程的加快,建设用地增加明显,水域面积持续增加,草海湿地继续得以保护.     

漾濞江流域土地利用变化分析

在遥感和地理信息系统技术的支持下,利用1990年和2001年的遥感影像作为信息源,分析了漾濞江流域土地利用变化特征.结果表明:林地面积增加2 791.71 hm2,城乡工矿居民用地面积增加1 290.55 hm2,草地面积减少4 014.18 hm2;土地利用总体变化速度较快,综合土地利用动态度为0.77%;土地利用程度变化不大,1990年和2001年土地利用程度综合指数分别为215.037和215.567,土地利用仍处于发展时期;研究区仍有2 148.45hm2的耕地需要退耕还林、还草.     

延安市退耕还林前后土地利用动态变化分析

以延安市1989—2012年土地利用动态数据为基础,研究了土地利用的结构、动态度、强度等时空变化特征,并采用景观优势度和景观均匀度等景观格局指标对景观格局变化进行分析.结果表明,退耕前的1989—1999年,延安市各主要土地利用面积变化均不大;退耕后的1999—2012年,土地利用面积变化加快,面积减少最多的为耕地,增加最多的为林地,耕地和林地变化强度远大于其他类型土地;退耕前后的土地利用变化强度指数差异较大,退耕后明显大于退耕前;退耕还林工程的实施有效推动了耕地向林地的流转.延安市景观格局变化以退耕还林工程实施为节点,土地利用优势度先降后升,均匀度先升后降,工程的实施提高了以林地为主体的生态用地对土地利用的支配程度;但随着林地增加,耕地和牧草地减少,土地利用均匀性降低,土地利用丰富度减小,在以后的土地利用中要注重对生态环境建设成果的巩固和保护.     

基于RS与GIS技术的豫西山地典型区域LUCC动态监测研究

借助RS和GIS软件对研究区域3个时期的遥感影像进行监督分类,得到两个时段的土地利用变化转移矩阵和不同土地利用／土地覆被类型的空间转化过程．进一步的分析认为近十几年来研究区域土地利用变化的空间景观特征表现为：1987～1996年未利用土地的面积变化最大,林地和农业用地的破碎化趋势比较明显;1996～1999年林地的面积变化最大,未利用土地的空间分布呈分散化趋势．研究期内土地利用结构时空变化表现为：土地利用程度由衰退期或调整期转变为发展期,土地利用的时间动态特征由快速变化型转变为慢速变化型。     

近10年来福州市土地利用动态变化研究

根据福州市2002年-2011年土地利用现状数据,利用数学统计方法对福州市土地利用动态变化进行分析.结果表明,2002年-2011年福州市土地利用数量变化中,耕地、园地和其他土地面积都有所减少,动态度变化方向呈负向;林地、其他农用地、城镇村及工矿用地、交通运输用地、水利设施用地面积在增加,动态度呈正向发展.2002年-2011年福州市土地利用程度变化量为11.65,处于发展期.市域内由于发展条件存在差异,土地利用程度变化量也存在差异,福州市还需调整土地利用结构,提高土地节约集约化程度.     

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.     

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.     

Tracking data management using topology of moving object database system for moving object constrained trajectory in LBS application

Advances in wireless technologies and positioning technologies and spread of wireless devices, an interest in LBS (Location Based Service) is arising. To provide location based service, tracking data should have been stored in moving object database management system (called MODBMS) with proper policies and managed efficiently. So the methods which acquire the location information at regular time intervals then, store and manage have been studied. In this paper, we suggest tracking data management techniques using topology that is corresponding to the moving path of moving object. In our techniques, we update the MODBMS when moving object arrived at a street intersection or a curved road which is represented as the node in topology and predict the location at past and future with attribute of topology and linear function. In this technique, location data that are corresponding to the node in topology are stored, thus reduce the number of update and amount of data. Also in case predicting the location,because topology are used as well as existing location information, accuracy for prediction is increased than applying linear function or spline function.