Non-resonance conditions for uniform observability in the problem of nonlinear output regulation

This paper deals with the design of an internal model-based semiglobal output feedback regulator for possibly non-minimum phase nonlinear systems. Taking advantage of the design tool proposed in Isidori (IEEE Trans. Automat. Control 45 (10) 2000), we show how the problem of output regulation can be reformulated into an output feedback stabilization problem of a suitably defined extended auxiliary system. The output feedback stabilization of the extended auxiliary system is addressed in the second part of the paper, where an observer-based stabilizer is proposed. The existence of the latter is characterized in terms of necessary and sufficient conditions which can be interpreted as nonlinear non-resonance conditions between the modes of the exosystem and the zero dynamics of the controlled plant.     

TYB系列注水调压泵在油田注水中的应用

文章结合现场使用情况,论述了我国在用注水系统中存在的问题;详细介绍了注水调压泵结构及工作原理、使用的前提条件及注水调压泵与柱塞式增压泵的对比特点.简要展望了调压泵在油田开发中的应用前景.     

牡丹江水力发电总厂水库调度持续完善管理

水库调度持续完善管理是以持续完善的理念为指导,以提高水能利用提高率为核心,以追求更高的发电效益和工作效率为目的,不断寻求对水库调度管理有效性和效率的完善,并采取渐进的日常完善和阶段性完善相结合的方法,逐步实现水库调度科学比、规范化、现代化的发展目标.     

浦东新区水环境治理措施

对前几年上海浦东新区的河道治理、污水排放治理和水文资源调配等水环境治理情况进行了总结,分析了整治过程中存在的问题,并对以后的水环境建设提出了切实可行的措施。     

Habitat associations of upper Volga river fishes: Effects of reservoirs

Habitat associations of upper Volga river fishes are defined within a cycle of spawning, feeding and overwintering migrations. The migration cycles of resident riverine fishes are categorized as obligate rheophils, limno-rheophils and limnophils. Forty-four fish species in 14 families occurred in the upper Volga River before regulation. Four mainstem reservoirs were constructed on the upper Volga between 1937 and 1957: Ivankovo, Uglich, Rybinsk and Gorky. They are maintained in a stage of delayed and sustained annual flood pulse. Additional impacts of reservoir construction include the creation of a new pelagic habitat, replacement of floodplains by lacustrine littoral and sublittoral habitats, creation of a complex bathyal habitat from former river channels and replacement of riverine flow patterns by pelagic water mass circulations. Populations of rheophilic species declined, while a new pelagophilic fish guild developed. Forty-six fish species are now present; seven species were lost and nine introduced after impoundment. Spawning, feeding and wintering habitats are outlined for reservoir guilds. Ichthyomass increased three to four times following reservoir construction and commercial fish harvest from Rybinsk Reservoir between 1945 and 1992 ranged from 2220 to 4304 t/y. Reservoirs of the upper Volga have limited bioproductivity due to a deficiency and uneven distribution of reproductive habitats, decreasing bottom irregularity, seasonal anomalies of flooding and draining of the littoral and sublittoral and underestimating the importance of tributaries. Lack of littoral reproductive habitat can be remedied by increasing the area of protected littoral through the construction of chains of small islands, diking and reclamation of bogged areas. Improved reproduction of migrating local stocks can be achieved by removing sand bars across tributary mouths, construction of artificial spawning grounds and restoration and preservation of preferred habitats in the main channel.     

超高压水压机的调压原理

针对超高压水压机，提出用改变增压器行程来调压的原理，给出了增压器行程与压力增量间的关系式。该原理已用于生产、调压简单、稳定可靠。     

8098单片机控制的感应电机启动节能器

介绍以8098计算机作微控制器,用PL/M高级语言开发软件的一种高效启动节能器。文中对8089单片机及PL/M语言进行了必要的说明。最后介绍了它们的实际应用——节能器的软、硬件设计。     

黄河下游造床流量的变化及其对河槽的影响

本文通过计算黄河下游的第一造床流量和第二造床流量，分析了黄河下游河槽的萎缩过程。第一造床流量与年水沙量的关系分析表明，黄河下游的深槽平浅滩流量700～1000m3/s是相对稳定的，恒定流的平衡输沙能力约为18～21kg/m3。通过小浪底水库拦粗排细年平均拦沙约3亿t，并在汛期强化调水调沙运用，基本可以控制黄河下游河槽的淤积萎缩。第二造床流量和平滩流量的关系分析表明黄河下游恢复和维持平滩流量约4000m3/s的中水河槽是比较合理的。根据小浪底水库调水调沙运用状况，提出了恢复和维持黄河下游稳定中水河槽的措施，并探讨了强化小浪底水库调水调沙运用的方案。     

Ecological perspectives on regulation and water allocation for the Ord River,Western Australia

Water management agencies throughout Australia are attempting to find a balance between the water requirements of ecological and socio‐economic environments as part of a holistic approach to managing flow‐dependent river ecosystems. Environmental water provisions are under consideration for the Ord River in far northern Western Australia. This river has been regulated for irrigation and there are plans for substantial expansion. Like other semi‐arid and tropical rivers, however, the hydrology of the Ord River is highly variable and unpredictable, and therefore, proportionate water release strategies for the environment that are based on average monthly flows are unsuitable. Regulation continues to produce pronounced ecological changes throughout the river system as the impacts of flow regime are negated. There is a dichotomy in optimal flow regimes for the contrasting management aspirations of ecological restoration based on low seasonal flows, and the dilution flows required for the drainage of agricultural effluent. Whilst current agricultural land and water management practices continue, the two cannot coincide, and consequently, a decision should be made regarding which environmental water allocation holds the primary value. Such a decision would guide the appropriate dry season flow regime on the lower Ord River. Copyright © 2002 John Wiley & Sons, Ltd.     

一种精密稳压的150 V直流电源电路

介绍一种利用低电压普通集成稳压器LM317精密稳压的150V直流稳压电路，电路采用两个NPN晶体管实现了LM317输入、输出端之间的限压、稳压和输入端的限流，电路结构简单，工作可靠，并且具有较高的稳压精度。