返回舱水上冲击特性的试验研究与理论计算

本文通过相似缩比模型的撞水试验，得到了返加舱水上降落时的冲击载荷与入水深度，并用理论分析的方法对返回舱的水上冲击特性进行了计算，证实了理论预报的可行性。     

维持通航建筑物口门水深的护底加糙措施研究

提出护底加糙的壅水工程措施以解决通航建筑物水深不足。通过对其论证分析发现，加糙效果与加糙材料粒径直接相关，同时粒径的选取应综合考虑自身稳定性、水位壅高效果、比降和局部流速变化，避免造成新的碍航问题。在此基础上，针对三峡建库后葛洲坝船闸可能出现的水深不足情况，通过理论分析以及数值模拟，比较了不同加糙方案的壅水效果。该措施还具有设置或拆卸的灵活性，工程风险小等优点。     

遗传算法在推求流量—水深关系中的应用

本在标准遗传算法（SGA）基础上，提出一种基于实数编码的遗传算法（RGA），解决了标准遗传算法（SGA）算法及献[1]中华罗庚优选法的循环次数过多、耗时长以及过早收敛、形成局部成等问题。并渴望在水利工程设计中多维、高度非线性等参数优化问题中得到应用。     

Liquidity Provision of Limit Order Trading in the Futures Market Under Bull and Bear Markets

Abstract:  This study investigates how limit orders affect liquidity in a purely order-driven futures market. Additionally, the possible asymmetric relationship between market depth and transitory volatility in bull and bear markets and the effect of institutional trading on liquidity provision behavior are examined as well. The empirical results demonstrate that subsequent market depth increases as transient volatility increases in bull markets. Market depth exhibits significantly positive relationship to subsequent transient volatility in bull markets. Additionally, although trading volume positively influences transient volatility in bull markets, no such relationship exists in bear markets. Liquidity provision decreases when institutional trading activity intensifies during bear markets. Thus, liquidity provision for limit orders differs between bull and bear markets.     

Accurate environmental bioindication in floodplains in spite of an extreme flood event

The ecological reaction of species on environmental factors can differ both, temporally and geographically. Therefore, bioindicator systems must be shown to remain accurate at different places and points of time. Extreme events pose challenges for testing this robustness, which has not yet been explored systematically. The unique opportunity of the extreme flooding of the river Elbe in August 2002 was used for such a test. The bioindicator system for mean groundwater depth during the vegetation period and annual duration of inundation in floodplains studied here was developed with data collected in 1999. Data from 2003 were used to analyse the dependence of the bioindication results on the humidity of the study plots and taxonomic group (plants, molluscs and carabid beetles). For the duration of inundation, the accuracy of bioindication in 2003 was similar to that in 1999, except for the medium‐humid and dry plots using molluscs as indicators. For groundwater depth, the accuracy of bioindication in 2003 was similar to that of the reference year except in the dry plots with significantly lower accuracy for all species groups. With a few exceptions, the bioindicator system is shown to be robust and to remain accurate in spite of an extreme flood event. In conclusion, the relevance of extreme events for the robustness of bioindicator systems differs between the indicated parameters and taxonomic groups. The results stress the need to take into account the limits of the working range and the occurrence of extreme events, when testing and applying bioindicator systems. Copyright © 2009 John Wiley & Sons, Ltd.     

RETRIEVING RIVER ATTRIBUTES FROM REMOTELY SENSED DATA: AN EXPERIMENTAL EVALUATION BASED ON FIELD SPECTROSCOPY AT THE OUTDOOR STREAM LAB

This paper summarizes experiments conducted at the Outdoor Stream Lab to gain insight on the relationships between a channel's spectral characteristics and the river attributes of interest to scientists and managers. Improved understanding of these connections would advance the application of remote sensing to fluvial systems. Motivated by this objective, we examined the following: (i) interactions among local hydraulics, water surface roughness and surface reflectance; and (ii) the influence of periphyton development and streambed disturbance on bottom reflectance. These experiments could thus lead to novel methods for inferring flow velocity and substrate type, respectively, from passive optical image data. Our initial results indicate the following: (i) water surface reflectance can compromise spectrally based depth retrieval by reducing the range of useful wavelengths and weakening correlations between band ratios and depth, implying that removing the surface‐reflected component of the total radiance could facilitate bathymetric mapping; (ii) water surface roughness was influenced by local hydraulics and was positively correlated with water surface reflectance, suggesting that observations of surface reflectance could be used to infer flow velocities; (iii) substrate spectral characteristics were influenced by the degree of periphyton development, implying that algal biomass might be estimated from remotely sensed data; and (iv) similarly, bottom reflectance differed significantly for intact versus disturbed substrates, suggesting that areas of streambed disturbance might be identified via remote sensing. Future work will focus on further elucidating connections between surface reflectance, water surface texture and flow velocity, and developing quantitative relationships between bottom reflectance, periphyton abundance and the degree of streambed disturbance. Copyright © 2013 John Wiley & Sons, Ltd.     

真空预压加固深度分析与探讨

本文依据真空预压现场监测数据,对孔隙水压力、分层沉降、深层土体水平位移在真空预压过程中沿深度的分布规律进行统计与分析,结合软土层厚度以及排水板打设深度等条件,认为在现有数据条件下真空预压加固有效深度与排水板打设深度密切有关,至少可以达到排水板打设深度(23 m)以下2~3 m范围。     

水电工程混凝土喷护方法的探讨

通过对干喷、湿喷、并列法喷护的剖析，针对其利弊开发出另一种介于干喷和半湿喷护方法，并对半湿喷护法的优缺点加以分析，探讨了半湿喷护法的工艺流程、喷嘴结构形式、水环结构及其效应。初步试验成果表明，半湿喷护法在技术上是可行的，经济效益也显著，可在逐步研究完善后推广应用。     

VB6．0在U型渠道断面设计中的应用

在日益发展的节水灌溉工程中，U型渠道断面得到了广泛的应用，但是在确定渠道断面尺寸的水力计算中，大都采取对高阶隐函数进行试算或图角法来完成，过程十分繁琐，为了方便计算，本利用VB6．0进行编程，求解U型渠道中的正常水深ho和流速v，结合实例说明思路，结果表明计算精度高，便于应用，可供水利工作参与。     

RELATIONSHIP AMONG EVAPORATION FLUX OF GROUNDWATER, DEPTH OF WATER TABLE AND NEGATIVE PRESSURE HEAD IN BARE SOIL

1.　 INTRODUCTIONThe crisis of water resources is a global problem.Compared with other countries,Chi-na relatively falls shortof water resources.The amount of water resources per capita is justone fourth as the world average value. The distribution of water resources is outof balance.81 % ofthe water resources is concentrated in the reach of the Yangtse River and the south-ern areas of China,while only1 9% is in the areas of the north to the Yangtse River,inwhich the population is4 5.3%…