区域性中心城市CBD建设的动因及发展策略

结合中央商务区（CBD）的概念,从全球经济一体化的趋势和国家发展战略入手,阐述了大连CBD建设的背景,探讨了适合大连的CBD发展思路,提出了大连CBD建设的目标及策略,为国内其他城市CBD建设提供了指导。     

河南省白沙灌区信息化建设

河南省白沙灌区信息化建设起步较早,近年来,开展了灌区管理信息化技术研究,提高了灌区的管理水平和效率。白沙灌区管理信息系统融合属性数据和空间数据,实现了对灌区的基本情况、统计资料、空间信息、相关报表的查询和分析,做到了地理信息与数据库信息的关联查询。该系统充分利用现代信息技术、计算机技术、地理信息技术,已为灌区管理部门提供了科学的决策依据。     

夹马口灌区年度灌溉引水计划的制定与执行

文中论述了夹马口灌区年度灌溉引水计划的制定与执行情况,灌溉计划的制定是按以下步骤进行的。首先,根据夹马口灌区年度作物种植面积,灌溉定额,灌区试验站降雨资料,渠道水利用系数制定年度引水计划;再依据各支渠、各干渠管理段五年的实际引水量占全局总引水的百分比作为当年配水比例。     

景泰川灌区水循环要素变化特征研究

为了深入研究景泰川灌区变化环境下水资源形成及水循环演化规律,实现高扬程引黄灌区水资源高效合理利用与生态环境保护,研究选用Mann-Kendall趋势检验法和非参数Mann-Kendall突变检测法对景泰川灌区1960-2008年的降水量、蒸发量等水循环要素进行时间变化特征分析。结果表明:灌区多年平均降水量为185. 49mm,49 a中,多年降水量的正负距平幅度大致相同,降水偏多与偏少期呈周期性交替出现;蒸发量多年平均值为2 554. 25 mm,其中有31a蒸发量低于此值;灌区夏季降水量占全年降水量的57. 4%,为四季最大,其次是秋季、春季,冬季的降水量为最小;夏春两季蒸发量分别占全年蒸发量的40%和33%,为主要蒸发集中时间,秋季的蒸发量次之,冬季蒸发量仅占全年的8%,为全年最少;在研究时段内,灌区年降水量没有发生突变现象;年蒸发量1972年出现降低的突变,1974年开始剧降,下降幅度大约为481. 4 mm。     

山东省博山区土壤元素分布特征研究

通过对山东省博山区土壤元素背景值状况的计算和研究,统计N、I、V、F、Cd、Cr、Hg、Co、K、P、Mn、Mo、Ni、B、Pb、As、Cu、Se、Zn、Ge、Sb、Fe、有机质等28种指标的表层土壤地球化学特征参数,查明了土壤元素分布特征、富集贫化规律,对其与全国、全省同类参数的差异进行了分析。结果表明,含量的显著特征是高Mn、F、P、Sr,而低Hg;大部分元素在表层土壤中的含量继承了土壤母质的成分特征,但Cd、Cr、Hg等受人为活动和污染源的作用在表层土壤中明显富集。区内土壤环境质量水平总体较好,部分重金属元素分布受地质背景控制,污染地块面积小。研究区Se、Zn、Ge等元素丰富,特色土地资源具有良好的开发前景。     

Analysis of Livelihood Asset Pentagon to Assess the Performance of Irrigation Systems

Abstract

There has been a growing consciousness for the need for a framework that is holistic and comprehensive in the assessment of irrigation system performance. This paper presents the results of statistical tests conducted on the analytical framework developed in Part 1 of the paper to examine whether or not it addresses the important issues of system performance. Information collected from two farmer-managed irrigation systems of Nepal was used to test the validity of the framework. The empirical evidence shows that the framework is valid in identifying and fitting conventionally-overlooked livelihood assets and that it demonstrates differences in farm households' access to these assets resulting in varying performance of irrigation systems.     

Experimental evaluation of radiator control based on primary supply temperature for district heating substations

In this paper, we evaluate whether the primary supply temperature in district heating networks can be used to control radiator systems in buildings connected to district heating; with the purpose of increasing the ΔT. The primary supply temperature in district heating systems can mostly be described as a function of outdoor temperature; similarly, the radiator supply temperature in houses, offices and industries can also be described as a function of outdoor temperature. To calibrate the radiator control system to produce an ideally optimal radiator supply temperature that produces a maximized ΔT across the substation, the relationship between the primary supply temperature and outdoor temperature must be known. However, even if the relation is known there is always a deviation between the expected primary supply temperature and the actual temperature of the received distribution media. This deviation makes the radiator control system incapable of controlling the radiator supply temperature to a point that would generate a maximized ΔT.     

Simple Method for the Design of Microirrigation Paired Laterals on Sloped Fields

In this study, a method for designing paired laterals that meet with required water application uniformity on sloped fields was developed using the energy gradient line approach based on the definition of the best submain position locations in which the same minimum pressure exists in uphill and downhill laterals. The best equation form of best submain position was determined. Also, the solution procedure was introduced to get the final solution to avoid the phenomena of no convergence or slow convergence. In this method, the required water application uniformity was used directly as a computational parameter in designing. When the designed emitter discharge, required water application uniformity and one parameter (either length or diameter) of a paired lateral are provided; the system developed here enables another parameter and the best submain position to be determined for any field slope conditions. Taken together, the results of this study show that final solutions can be obtained quickly and reasonably.     

红旗陂农民用水协会的组建及灌区管理实践

本文介绍了江西省于都县红旗陂农民用水户协会组建的主要做法和成效，供同行参考。     

Hydraulic Analysis and Optimum Design of Multidiameter Irrigation Laterals

A new analytical continuous-uniform outflow approach that takes into account the effect of the number of outlets on the multidiameter lateral hydraulics is presented. The pressure head profile along the multidiameter pipeline is described by a simple analytical function providing direct calculation of the outlet pressure head along the pipeline. The method is significantly improved by introducing an adjusted spatially variable outflow equation—of power function form—for the errors caused by the assumption of equal outlet discharge. The effect of ground slope on hydraulic computation is also considered. Simple equations are derived for the direct calculation of the maximum, minimum, and inlet pressure head along the multidiameter pipeline. The optimum design problem for two-diameter laterals is also solved analytically. For specified total length of a two-diameter pipeline, a simple algebraic equation is derived to calculate directly the appropriate lengths of the reaches of different diameters in such a way that the total cost of the pipeline is minimized. Comparison tests with an accurate numerical stepwise method indicate that the proposed analytical approach is sufficiently accurate.