PID控制器在农村供水工程控制系统中的应用-以红谷田水库为例

当前,我国农村用水粗放现象较为普遍,节水型生产和生活方式尚未建立.通过对取用水单位及其供水对象加强供水计量设施的自动化建设,并提高水源自动化监控能力,是缓解资源性缺水与工程性缺水的有效措施,对深化农村节水降损具有十分重要的意义.本文介绍了PID比例、积分、微分控制技术,采用临界比例度法现场调试整定PID控制器参数,实现...     

中国出境旅游"双高"格局与政策取向辨析——兼与戴学锋、巫宁同志商榷

中国出境旅游的高增长和高消费现象引发了对出境旅游不经济性的讨论.本文通过与"中国出境旅游高速增长的负面影响探析"一文作者的商榷,认为出境旅游的迅速发展是我国现阶段宏观经济发展的必然结果,属于"补涨"性质;出境旅游消费存在"虚高"现象;出境旅游的发展为我国旅游业跨国经营创造了有利条件,而跨国经营是克服出境旅游不经济性的最佳途径.     

合同法上的附随义务初探

合同义务的一个重要分类是给付义务与附随义务。附随义务是指法律无明确规定,当事人间也无明确约定的合同当事人应承担的义务。在合同履行过程中,违反了附随义务应承担相应的法律责任。     

系数修正法在标定地价评估中的应用

本文从务实的角度出发, 系统阐述了系数修正法在标定地价评估中的应用。文中首先论述了系数修正法的基本原理,然后详细分析了影响地价的各种因素并给出了利用系数修正法评估地价的具体步骤, 最后通过评估实例进行了说明     

谈施工企业物资设备的集中采购管理

<正>施工企业的主营业务是承揽各类工程项目,并按合同要求组织实施后将建筑产品交付业主,从而获得自身的利润。工程项目按时履约并获得预期收益,是保证企业持续良好发展的重要基础。工程项目的施工成本主要是由人员、物资材料、机械设备组成,其中,物资设备所占份额一般都会超过50%,所以控制物资设备的采购成本对项目的良好实施具有举足轻重的重要作用。有效降低采购成本,不仅能使工程项目顺利完成,使企业获得较好的利润并保持良性发展,也可为企业在后续经营中具备较好的竞争力。     

硗碛水电站砾石土心墙堆石坝填筑施工监理质量控制

介绍了硗碛水电站大坝施工技术特点和设计技术要求,以及填筑施工监理质量控制措施和质量检查情况。     

NUMERICAL INVESTIGATION ON THE HYDRODYNAMIC PERFORMANCES OF A NEW SPAR CONCEPT

Recently, the spar platform concept develops quickly in the offshore oil and gas exploitations, especially in deep and ultra-deep water, owing to its benign motion performance, excellent stability and adaptation to wide range of water depth. Many new spar concepts have been put forward with the purpose of reducing fabrication difficulty and cost, while meeting the requirements of exploitation in the meantime. Based on the aims mentioned above, a new spar concept was presented in this article and its hydrodynamics both in operating and survival conditions was studied by means of numerical simulation. Basic model tests were also conducted to calibrate the numerical approach. Following aspects are highlighted: (1) new spar concept, (2) global performance of the spar concept and (3) mooring line analysis.     

Influence of Seepage Face Obliquity on Discharge of Groundwater and its Pollutant into Lake from A Typical Unconfined Aquifer

Lab experiment and mathematical simulation Modular three dimensional finite difference groundwater (MODFLOW) were performed in a soil tank to simulate the hydrogeochemical interaction between lake and typical unconfined aquifer. Results show that the velocity decreases exponentially with the transect distance on seepage face. The maximal velocity occurs at the top point of seepage face. The obliquity of seepage face has a great influence on the maximum and distribution of seepage velocity. With the increase of the obliquity of seepage face, the maximal velocity decreases quickly and the velocity distribution becomes much more even. Most of groundwater flow and pollutant flux discharges through a narrow portion near the top of seepage face. The flow and mass concentrated in the narrow portion increase with the decrease of the obliquity of seepage face. These will benefit to design a reasonable and economical scenario to manage lakeshore and to control the pollution of lake water near lakeshore.     

水布垭地下厂房系统关键工程地质问题研究

水布垭水利枢纽地下厂房布置在右岸相对高差达360 m的马崖高边坡山体内,平面上夹持于坝区最大的两条断层F2与F3之间的"金三角"地带.几个关键的工程地质问题为:①进口庙包滑移体的稳定问题;②厂房顶拱块体的稳定问题;③厂房边墙软岩的稳定问题;④尾水洞围岩的稳定问题等.通过钻孔、平洞、斜平洞等勘察手段以及大量的现场原位试验与室内试验工作,查明了厂区岩体的结构特征及工程地质特性,论证了这些至关重要的工程地质问题,提出了相应的处理对策,为厂房系统的设计、施工打下了坚实的基础.     

企业环境绩效与经济绩效的动态关系模型

企业环境绩效与经济绩效的关系是企业战略管理研究领域里一个比较新的研究对象。现有的研究除方法和数据方面的缺陷外,主要问题是理论模型的解释力不强。本文认为组织能力是企业环境绩效与经济绩效之间内在联系的纽带,一个基于企业组织能力的环境绩效评估体系能够对企业改善环境绩效产生持续的激励作用。据此提出“基于组织能力的企业环境绩效”的理论模型,旨在从环境管理能力建设的角度来讨论企业环境绩效评估的基础方法和原则。