小型农田水利工程存在的主要问题及解决对策

前些年,国家投入水利建设资金主要用在大中型骨干工程的建设,小型水利工程投入较少。因此,小型农田水利工程仍是农田水利工程建设中最薄弱的环节,严重影响了小型水利工程的整体效益,并制约着农业和农村经济发展。针对小型农田水利工程的现状,为进一步提高农业综合生产能力,保障国家粮食安全和增加农民收入,从2005年起,中央和省级财政都设立了小型农田水利工程建设补助专项资金,提高了小型农田水利工程的建设,但是,如何搞好小型农田水利建设、提高工程的使用效率,仍然是十分重要又十分紧迫的课题。     

探析小型农田水利工程的施工建设和管理

由于农业科学技术的迅猛发展,实现农业可持续发展已经成为农业科学领域中的一项重要问题。在农业技术中,小型农田水利工程已经逐步成为农业发展的基础条件。小型农田水利工程的建设,有效的发挥了抗旱除涝的重要作用,进一步推动了农业的发展。然而,我国在小型农田水利工程的施工建设和管理中仍然存在很多方面的问题,严重的影响了农田水利工程作用的发挥。该文主要分析了农田水利工程的施工建设和管理。     

我国小型农田水利设施建设的问题与对策

小型农田水利工程对农业生产有着不可替代的作用。然而,目前我国小型农田水利设施建设中还存在设施产权不明晰等问题。要改变现状,必须既要实行小型水利工程产权制度改革,加强工程管理,又要确保增加对小型农田水利设施建设的投入。     

我国小型农田水利工程特性分析

本文基于笔者多年从事农田水利工程的相关工作经验，以小型农田水利工程的工程特性为研究时象，分析了小型农田水利工程的一般经济属性和公共物品属性。全文是笔者在长期农田水利工作基础上的理论升华，相信对从事相关工作的同行有着重要的参考价值和借鉴意义。     

八师地区小型农田水利工程中灌溉渠道的设计

近年来国家及地方对小型农田水利工程的投资力度不断加大,如何规划设计农田水利工程,使之更加切合实际、更加规范就成了关键性的问题。灌溉渠道的设计是农田水利工程中比较重要的一项内容,就新疆兵团第八师地区小型农田水利工程中灌溉渠道的应用设计作一简单介绍。     

浅议小型农田水利工程施工与管理

随着经济的发展,在农村经济工作中,小型农田水利工程起着举足轻重的作用。如何建设好小型农田水利工程,则需要重视施工,重视管理,努力克服工程建设中所存在的问题。本文针对农田水利工程的特点对小型农田水利工程施工和管理中问题进行简要分析。     

浅议东昌府区小型农田水利工程的建设与管理

水是农业生产可持续民展、促进农业增产、农民增收的基础条件,小型农田水利工程对水源的利用起到了举足轻重的作用,根据东昌府区的现状,对小型农田水利工程的建设与管理进行了分析。     

基于实践的“小农水”工程治理模式对比研究

小型农田水利工程治理的宗旨是提高工程利用率和灌溉用水效率,其服务对象是农民、农村和农业,受益主体是农民。本文以农田水利的治理模式为研究对象,对比研究了小型农田水利工程投入,驱动及中心治理三种治理模式,相信对从事相关工作的同行能有所裨益。     

小型农田水利设施的民间供给体制探析

近年来,对于小型农田水利设施民间供给行为的产生和发展引起了学术界的广泛关注,也取得了一些研究成果。但是,目前大多数研究都是围绕着小型农田水利工程的产权制度改革这一主体进行的。本文对小型农田水利设施的民间供给行为进行了相关的理论研究,探讨了影响农户投资小型农田水利设施建设积极性的障碍因素,又进一步结合当前形势,从宏观角度提出了一系列鼓励和引导农业基础设施民间供给行为的政策建议。     

浅谈小型农田水利工程建后管理问题

随着国家对水利工程建设的加大投资,小型农田水利建设进入到繁华期。由于历史欠账太多,工程建成后管理问题成为制约小型农田水利建设发展的又一问题。     

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.