Applied Mechanics and Materials Vols. 295-298

Abstract: Established multiple city domestic water system control model. Used new water population and fixed capital investment flow as control variables. The example result got the negative feedback control scheme, can realize the multiple city domestic water system simultaneous stabilization control.

Abstract: The response of wetland ecosystem of Poyang Lake influenced by hydrological process changes was addressed. The spatial distribution and area of water, water-land transition zone and exposed grass continent were obtained by classification and extraction of wetland based on Landsat-TM images and analysis of observed hydrologic data. The results indicated that wetland ecological system of Poyang Lake was characteristic of complexity,sensitivity,mutability and fragility, and the optimum water level of wetland in Poyang Lake was 10-14m.

Abstract: The wet and dry periods with multi-time scales of hydrological long-time series in Poyang Lake and Yangtze River were analyzed based on the method of Empirical Mode Decomposition (EMD). The results indicated that the variation of wet and dry periods of Yangtze River and Poyang Lake had diversified representation, and consistency with the meso and short scale periods. The reasons for the low water level emerged early and the lowest water level had breakthrough the history were explained.

Abstract: Beijing-Tianjin-Tangshan- Qinhuangdao area structurally lies in the fault-fold belt before Yanshan orogenic belt. The geothermal springs are divided into two types: the natural outcrop type and the hidden artificial type of heat reservoir, the former of which is controlled by piedmont faulted , extending EW; while the latter of which is controlled by regional structure and geothermal field. Geothermal spring water is low salinity and neutral even low alkaline water, whose chemical type is mainly SO4•HCO3- Na and SO4•Cl•HCO3- Na. As the water is rich in fluoride and multiple heavy metals, it pollutes drinking water, soil, crops in different degree during the development and utilization. H2S and CO2 in the geothermal water also does harm to the atmosphere more or less.

Abstract: This essay tries to research into the existing form of the nutritious elements in lake water--- nitrogen and phosphorus with geochemical theories, views and knowledge by analyzing the space-time distribution feature of Wuliangsu Lake nutritious elements-- nitrogen and phosphorus and its geochemistry environment under different pH values, temperature and pe values.

Abstract: The main theories of spatial autoregressive model and model selection were used to study the spatial correlation between suspended sediment, sea surface temperature and alga during summer 2011 in Changjiang estuary. The results indicated that: there were significant high spatial autocorrelations in the spatial distributions of suspended sediment, sea surface temperature and alga, respectively; Suspended sediment always had significant and positive spatial correlation effect on the distribution of alga, Sea surface temperature had significant and positive spatial correlation effect on the spatial distribution of alga in June and August, but this effect decreased in July; The spatial distributions of suspended sediment and alga were closely correlated. Suspended sediment was the key dominant factor of the growth and bloom of alga, also the source of nutriment of alga.

Abstract: Wuliangsuhai wetland located in Inner Mongolia Autonomous Region (IMAR) is selected as the study area to analyze the wetland seasonal variation of Inner Mongolia plateau. According to the growing conditions of water plants and the differences of water depth, the Wuliangsuhai wetland is divided into six typical areas, i.e. open water area, dense water weed area, reed area, swamp area, shallow water area and artificial reed area. The evolution trends and reasons of the six typical areas in terms of the seasonal variation of wetland characteristics are analyzed by using the Landsat TM/ETM data, the historical data and in-situ survey data. The purpose of the study is to find out the eutrophication control theory and technique measurements in the year. Due to the similar geographical and climatic conditions, the study results of Wuliangsuhai wetland can be expanded to other wetlands of Inner Mongolia plateau.

Abstract: In the Yellow Sea, two large terrains of tidal sand ridges developed, respectively, in the Subei Shoal and the West Korea Bay. Sediment supply, hydrodynamics and bedforms are critical factors to form them. In this paper, sediment composition, morphology of sand ridges, etc. are analyzed in terms of relevant factors and subsequently their formation mechanisms and evolution processes are careful compared.

Abstract: To study the influence factors of perennial outbreak blooms in Xiangxi Bay (XXB) upstream, field data of Chlorophyll a (Chl.a) and TN and TP, and sediment concentration,2010. The result show: the Chl.a concentration is higher in XXB upstream, January until the end of September is particularly serious, XX10 Chl.a concentration was 227.84 mg/m3 in Feb.7, XX07 Chl.a concentration was 215.98 mg/m3 in June.2; the high levels of nutrient from upstream flow is the main cause of perennial outbreak blooms in XXB upstream, and at the same time, the slope density current and adverse slope density flow also have a great influence to it.

Abstract: Water level has risen considerably since the impounding of Three-Gorges Reservoir in year 2003 and that might broaden and deepen the Yangtze River and the tributary of Three Gorge, will greatly slowdown the flow velocity to change hydrodynamic conditions. This changes Influence the Water Environment of Yangtze River and the tributary of Three Gorges Reservoir, especially eutrophication and algal bloom of the tributaries in Three Gorges Reservoir in recent years. For studying the course of algal bloom in the tributaries of Three Gorges Reservoir and the comprehensive prevention countermeasures, about the hydrodynamics of Yangtze River main stream and tributary in Three Gorges Reservoir must be carefully researched. In this article, general situation of the algal bloom of the tributaries in Three Gorges Reservoir were presented, and analysed on characteristics and influencing factors of breakout of algal bloom from certain self-conditions changes before and after impoundment of the Three Gorges reservoir, knowing that lower the nutrient input and improve water flow regime and flow velocity behaviors are the main measures of comprehensive prevention countermeasures of algal bloom in the tributaries of Three Gorges Reservoir; This research status of influence mechanism of hydrodynamic conditions on algal bloom and the research tendency of the tributaries’ hydrodynamic conditions on algal bloom in Three Gorges Reservoir were reviewed, which provided certain theory reference for study and prevention countermeasures of algal bloom in the Three Gorges Reservoir tributaries.