Study on Ecological Restoration Model of the Fluctuating Belt of Reservoir at the Xueye Lake in Laiwu City, Shandong Province

Fluctuating belt of reservoir is a dry-wet alternating area with special ecological conditions, quality of its ecological environment directly infl uences the reservoir ecosystem. This paper, on the basis of analyzing ecological functions and problems of the reservoir fl uctuating belt, elaborated the ecological restoration of the fl uctuating belt of the Xueye Lake in Shandong Province. According to the coastal planning types and water resource conservation needs, 4 ecological restoration models were given, i.e., pond wetland model, terraced fi eld model, conservation model, and consolidated embankment model(or Baokan model), and also 7 vegetation restoration models. Landscape planning and design of the reservoir fl uctuating belt was reviewed from the perspective of ecological restoration, to establish the eco-friendly fl uctuating belt, and this study has high promotional value.

Influence of Blade Number on the Performance of Hydraulic Turbines in the Transition Stage

To analyze the effect of blade number on the performance of hydraulic turbines during the transient stage in which theflow rate is not constant,six hydraulic turbines with different blade numbers are considered.The instantaneous hydraulic performance of the turbine and the pressure pulsation acting on the impeller are investigated numerically by using the ANSYS CFX software.The ensuing results are compared with the outcomes of experimental tests.It is shown that thefluctuation range of the pressure coefficient increases with time,but the corresponding range for the transient hydraulic efficiency decreases gradually when theflow velocity transits to larger values.During the transition to smallflow velocity,thefluctuation range of the pressure coefficient gradually decreases as time passes,but the correspondingfluctuation range of its transient hydraulic efficiency gradually becomes larger.Thefluctuation range in the Z9 case is small during the transition.The main frequency of transient hydraulic efficiency pulsation is equal to the blade frequency.At the main frequency,Z7 has the largest amplitude of the hydraulic efficiency pulsation,Z10 has the smallest amplitude,and the difference between Z7 and Z9 is limited.As the number of blades grows,the pressure pulsation during the transition process gradually decreases,but the pressure pulsation of Z10 at the volute tongue is larger.In the steady state,Z9 has the highest efficiency and in the transient stage,the pressure coefficientfluctuation range is small.Accordingly,for the hydraulic turbine Z9,the performance is optimal.

Stratigraphy of late Quaternary deposits in the mid-western North Yellow Sea

The North Yellow Sea(NYS) is characterized by strong land-sea interaction and paleoenvironmental changes with sea-level fluctuations during the late Quaternary. However, large-time scale depositional stratigraphy in this area and its relationship with sea-level changes remain unresolved. Highresolution seismic profiles from NYS were subdivided into eleven seismic units(U1 to U11 in descending order). A 70.6-m-long borehole(DLC70-2) from localities on seismic profiles, analyzed for lithology, microfossil assemblages and geochronology, comprises eleven sedimentary units(D1 to D11 in descending order), which were clearly correlated with the eleven seismic units. These units constitute four distinctive sequences(SQ1 to SQ4 from top to bottom) bounded by three sequence boundaries(S3, S5 and S10) with obvious depositional hiatus, correlated with sea-level lowstands of MIS2, MIS4 and MIS6, respectively. The lowermost SQ4 below S10, has been identified only upper part of transgressive systems tract(TST)(D11, tidal flat facies in early MIS6). SQ3 overlying S10 consists of a set of lowstand systems tracts(LST)(D10, fluvial to incised-channel filling facies in late MIS6), TST and highstand systems tracts(HST)(D9 to D6, interactive deposits of neritic and littoral facies in MIS5 and early MIS4). SQ2 above S5 is composed of LST(D5, channel-filling facies in late MIS4) and TST(D4, littoral to estuary facies in early-middle MIS3), but lack of HST resulting from subaerial exposure and channel incising during the Last Glacial Maximum(LGM). The uppermost SQ1 overlying S3 comprises LST(D3, channel-filling to flooding plain or marsh facies in MIS2), Holocene TST(D2, littoral and tidal sand ridge facies) and HST(D1, neritic facies). The unusual depositional stratigraphy was largely dominated by sea-level fluctuations and the Bohai Strait topography. This study confirms that TSTs are relative continuous and widely distributed, while LSTs vary considerably in thickness and lateral extent since MIS6 in NYS.

Grain Prices in China: a Review and Policy Proposals

Based on in-depth analysis of grain price fluctuations and their repercussions since 2003, this paper summarizes national grain price control measures undertaken in recent years, identifies their effects and remaining problems, and calls on relevant departments to pay close attention to current grain production and the grain market. Lastly, the paper puts forward policy proposals for making price regulation more predictive, directed and e ective.