商丘市小麦白粉病预测模式研究     

余卫东  朱晓东  杨君健  刘伟昌 《河南气象》2008,31(1):20-23

以商丘市1995-2005年的小麦白粉病发病面积、地面气象资料和大气环流特征量为依据,利用相关系数法进行因子普查,筛选出了影响商丘市小麦白粉病发生和流行的主要地面气象因子和大气环流特征因子及其关键时段,并利用多元线性回归方法建立了数学预测模型,模型历史拟合准确率为95．2％。利用该预测模式在2006年和2007年对商丘市白粉病发病面积进行预测,预报精度分别为93．1％和90．2％。  相似文献   

Recent studies on surface water–groundwater relationships at hydro‐projects in India using environmental isotopes     

U. Saravana Kumar  Suman Sharma  S.V. Navada 《水文研究》2008,22(23):4543-4553

Environmental isotopes (²H or D, ¹⁸O, ³H), along with geology, hydrochemistry and in situ physicochemical parameters (EC, T, DO, pH) were employed to study surface water (reservoir, lake)–groundwater (spring) relationships at (1) Nagewadi, a minor irrigation project in the State of Maharashtra, Western India; (2) Kanhirapuzha reservoir in the State of Kerala, Southern India and (3) Ghatghar Pumped Storage Hydroelectric Project in the State of Maharashtra, Western India for the purpose of understanding the seepage/leakage and its associated problems. The studies concluded that the springs found downstream of the Nagewadi project originate from the reservoir and not from the abutments or shallow aquifers. The Kanhirapuzha reservoir receives a substantial base‐flow component compared to riverine inputs. The reason for the water‐logging problem at a nearby downstream village during the non‐summer periods is due to the change in the upstream groundwater flow direction under reservoir filling conditions and is not due to reservoir leakage. Most of the springs in the approach tunnel to the underground power house of the Ghatghar Project originate from the lower reservoir and not from the upper reservoir or the overburden rock matrix. The above case studies illustrate the diversity of environmental isotope applications in surface water (reservoir, lake)–groundwater (spring) relationships related to sustainability of hydro‐projects. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

Reviewing urban revitalisation strategies in Rio de Janeiro: from urban project to urban management approaches     

Claudio 《Geoforum》2001,32(4)

This paper describes key urban development strategies pursued during the last seven years by the Municipality of Rio de Janeiro, the second largest city in Brazil. It discloses internal processes, organisational restructuring of the municipality and institutional changes geared to increase effective urban management and resource mobilisation required to implement multiple sector programmes and key projects in several locations in the city like Favela Bairro and Rio Cidade Programmes, The Rio Strategic Plan, etc. It is argued that the formation of interdepartmental working groups for better horizontal articulation of policy making and implementation, the creation of the financial and accounting unit, the decentralisation of authority towards sub-municipality levels, and capacity strengthening of its personnel – among other things – have made a positive impact on the performance of local government. The paper further highlights a significant change towards policies of urban consolidation and revitalisation of declined areas of the city supported by heavy public investments and the effort towards broader civil society involvement in municipal projects. Municipal autonomy, problem-solving and result-oriented type of planning and management and organisational change are some of the lessons pinpointed by the paper for a city of that size and complexity.  相似文献   

Multiple Identities and Representations: Experiences in the Study of People's Life-worlds in Rural Malawi     

Fletcher Tembo 《Singapore journal of tropical geography》2003,24(2):229-241

This paper argues that in generating perceptual meanings of social actors as data, researchers need to deal with multiple representations, identities and categorisations of their own and those of their informants. The need to also consider power dynamics that develop in the communication process between the “researcher” and the "researched" in the process of generating data is also emphasised. The paper suggests that an analysis of image‐conflicts can be used to reveal the “hidden meanings” during these research encounters and improve the quality of research findings.  相似文献   

IMU/DGPS supported photogrammetry in China     

李英成  LI Xue-you  ZHAO Ji-cheng  GONG Xun-ping  TANG Liang 《测绘科学》2004,29(Z1):42-46

<正>People'sRepublicofChinaisoneofthemostrapidlydevelopingcountriesintheworldtoday.Thereisagreatdemandonhighlyactualandaccuratespatialinformationofthewholecountry,especiallyofWestChinawhichbecomesthefocusofdevelopmentoftheChinesegovernmentrightnowandinthenextyears,butwherestillnotenoughtopographicmapsareavailable.ThisraisesgreatchallengestothesurveyingandmappingcommunityinChina.FacingthenewchallengestheChineseAcademyofSurveyingandMapping(CASM)starteditspioneerworkearly2002toexplorenewtechniquesandtechnologiesavailabletodaytowardincreasingthemapproductivity.WithimportofaCCNS/AEROcontrolsysteminNovember2002,thefirstDGPS/IMU-basedphotogrammetricprojectinChinawassuccessfullyaccomplishedjointlybyCASM,theGermany-basedcompaniesIGIandTechedge.Twophotogrammetricblocksof1:4,000and1:20,000photoscales,respectively,wereflowninAnyang,China.Directgeoreferencingandintegratedsensororientationwereconducted.Resultsachievedwereprovenbyusinggroundcheckpointsandcomparedwiththoseofaerialtriangulation.Orthophotosgeneratedbasedondir  相似文献   

建设工程抗震设防工作中的问题及对策   总被引：1，自引：0，他引：1  

宋德忠 《国际地震动态》2006,(5):21-24

重大建设工程和可能引起严重次生灾害的建设工程,必须依法进行地震安全性评价,并依据评价结果进行设计、施工,这对于提高抗震设防能力,确保经济、社会健康可持续发展和保证人民群众生命财产的安全将发挥重要作用。但是,目前该工作存在许多问题,若不及时加以解决,将直接影响防震减灾工作的整体发展。结合工作实践和体会,提出对策。  相似文献   

青藏高原碰撞造山带成矿作用：构造背景、时空分布和主要类型   总被引：84，自引：6，他引：84       下载免费PDF全文

侯增谦莫宣学  杨志明王安建潘桂棠  曲晓明聂凤军 《中国地质》2006,33(2):340-351

大陆成矿作用是当代区域成矿学研究的重大前沿,增进对大陆碰撞造山带成矿作用的理解和认识是孕育和建立大陆成矿理论框架的核心和关键。长期以来,由于对系统完整地记录大陆碰撞过程的典型造山带的成矿作用缺乏深入系统的研究,对碰撞造山过程及壳/幔相互作用与成矿作用的耦合关系和成因联系缺乏深刻的理解,导致了对碰撞成矿阶段以及各阶段动力学过程认识不清,引发了较多争议。青藏高原造山带,成矿规模大、形成时代新、矿床类型多、保存条件好,为系统地研究大陆成矿作用、解决上述存在的问题提供了天然实验室。“印度-亚洲主碰撞带成矿作用”973项目组通过对青藏高原碰撞造山带成矿作用历时3年的系统研究,建立了青藏高原重要成矿事件的时空坐标,初步建立了成矿作用的地球动力学模型或构造控制模型,提出了一套完整的大陆碰撞带成矿理论新框架,包括三大成矿作用和12种矿床类型:同碰撞造山成矿作用(65-41 Ma,4种矿床类型),晚碰撞转换成矿作用 (40-26Ma,4种矿床类型),后碰撞伸展成矿作用(25-0 Ma,4种矿床类型)。其主控因素分别为:碰撞造山背景、壳源岩浆活动和大规模剪切变形;陆内转换背景、幔源岩浆活动和大规模走滑-推覆-剪切作用;后碰撞伸展环境、壳/幔岩浆作用和热液对流系统。  相似文献   

氧化物晶胞参数和配位多面体几何要素的关系     

韩照信 《地球科学与环境学报》1998,20(4):27

氧化物矿物中的化学键主要是离子键,结构可看成配位多面体以不同方式相连形成,因此,晶胞参数可用配位多面体几何要素表示,这样求得的晶胞参数与实测晶胞参数间的相对误差一般在百分之几。  相似文献   

城市环境工程地质图基本要素与编制原理     

李相然  琰勋 《地球科学与环境学报》1998,20(2):42

分析了编制城市环境工程地质图的意义,研究了城市环境工程地质图的基本要素与特点,并对其编制原则与方法进行了探讨。  相似文献   

沉积地层中坠石的成因及其研究意义     

王德英  王东坡 《世界地质》1996,15(4):21-25

坠石是沉积时落入水体底部沉积物中的单个或集群状外来碎屑，按其搬运载体不同可分为：（１）冰筏成因坠石：冰山作用形成的坠石和季节性冰体形成的坠石；（２）非冰筏成因坠石；动物植成因坠石和其它成因坠石。坠石是寒冷气候的标志，其形成时的气候具有多解性。  相似文献