Effects of plant community composition and exposure to wave action on invertebrate habitat use of Lake Huron coastal wetlands

Invertebrate communities from different coastal marsh‐plant communities were compared along wave‐exposure gradients using data from 1994, 1998 and 1999. Data were subjected to correspondence analyses to search for patterns in invertebrate communities in relation to plant‐community structure and wave exposure. In 1994, quantitative plant‐ and sediment‐invertebrate samples were taken from nine habitats: four from inland, subsurface‐connected marshes and five from littoral, emergent marshes. In 1998, sweep‐net samples were taken from 13 plant communities: six on the exposed and seven on the protected side of an island. In 1999, 2–3 plant communities/sites were sampled with sweep nets from four sites around the Bay so that intersite differences between inner, less‐exposed and outer, more‐exposed habitats could be examined. In all three studies, correspondence analyses separated inland, protected or inner sites from littoral, exposed or outer sites, suggesting differences in invertebrate‐community structure. For example, Hydracarina and Asellidae occurred in large numbers in inland sites, but were less common or absent from exposed, littoral sites. Littoral marshes also separated along an exposure gradient with Tanytarsini and Orthocladiinae collectors of organic particles occurring in very high numbers in outer, exposed areas where organic particles from the pelagic zone entered the marsh. Certain plant‐community types clustered together (e.g. wet meadow and Scirpus) while others, such as Typha, stands clustered according to exposure to waves suggesting the importance of both plant‐community structure and wave exposure in determining invertebrate‐community structure. We present a conceptual model that suggests that invertebrates in Great Lakes' marshes are distributed along gradients of decreased mixing of pelagic water and increases in sediment organic matter from outer to inner marsh and between littoral and adjacent inland marshes. Some invertebrates do best on one end of these gradients, while the majority are generalists found across habitat types.     

PM2000水电厂生产运行管理系统

介绍了基于Web技术开发的PM2000水电厂生产运行管理系统的软、硬件结 构，详细阐述了该系统所具备的主要功能及其对提高水电厂生产运行管理水平所发挥的作用。     

关于混联梯级水电站经济调度的研究

提出采用具有附加线性约束的网络规划法，可把混联梯级水电站分解为几个子网络，简化了每个子网络的求解计算，从而加速大电网复杂的经济调度的计算速度。     

天荒坪电站500 kV开关站开挖与边坡整治施工——兼论开挖爆破对高边坡稳定的影响及对策

在大型水利水电施工中，经常遇到岩质高边坡稳定问题，天荒坪抽水蓄能电站５００ｋＶ开关站所处的地形地质条件非常复杂，本文着重介绍在边坡开挖和支护过程中，根据不同的地形地质情况所采取的控制爆破和支护措施。     

关于上海地区屋顶绿化的思考

在上海市平面绿化工作已初见成效,大型公共绿地越来越多,城市越来越美之时,构建立体绿化 成为当务之急。本文通过对上海地区屋顶绿化的现状及存在的问题的阐述,结合绿化植物的选择和维护的一 些基本理论,展示了屋顶绿化广阔的发展前景。     

Price-maker型水电厂策略性报价

用古诺模型研究了Price-maker型水电厂在电力市场下的策略报价问题.将系统中各厂商的竞争简化为己方和虚拟对手组成的双人博弈,提出一种基于历史数据、分析对手行为的可行方法.该方法通过分析历史可获得数据,求取对手成本函数参数及系统的逆需求函数,由此获得合理的对手策略估计,并求取在此可能对手策略下的己方最优策略,从而达到己方收益最大的目标.     

水电站施工辅助企业的建设与管理

介绍了某大型水电站施工辅助企业的建设和管理实例，探讨对该类项目的建设与管理经验。     

Multinational Companies,Technology Spillovers and Plant Survival*

How does the presence of multinational companies affect plant survival in the host country? We postulate that multinational companies can impact positively on plant survival through technology spillovers. We examine the nature of the effect of multinationals using a Cox proportional hazard model, which we estimate using plant‐level data for Irish manufacturing industries. Our results show that the presence of multinationals has a life‐enhancing effect only on indigenous plants in high‐tech industries, suggesting the presence of technology spillovers. In contrast, multinationals compete with each other in low‐tech sectors in the host country.     

郁江梯级水电站群联合优化调度初探

郁江梯级水电站群由西津、仙依滩和桂航3座水电厂组成。针对西津电厂出力变化频繁,加上西津下游两电厂装机容量较小,经常出现弃水,用增量动态规划法进行了联合优化调度探索,同时介绍马斯京根分段流量演算法。     

三峡水电站充水保压蜗壳平面非线性分析

采用自编的三维钢筋混凝土非线性有限元程序，对三峡水电站充水保压蜗壳进行了平面非线性分析，分析了钢蜗壳及外围钢筋混凝土的应力变形特性。非线性计算分析表明，在蜗壳进口断面处，虽然外围混凝土较薄，但在设计内水压力、结构自重和设备重量这些荷载组合作用下，蜗壳进口断面混凝土可能不会开裂，因此钢材应力均比较低，结构具有较高的安全度。说明现有配筋方案钢筋用量可能偏多，没有充分发挥钢材的作用，在进一步设计时可以适当优化。