金沙江下游支流黑水河松新电站幼鱼下行过坝研究

梯级小水电的开发一定程度上破坏了河流连通性并阻碍了鱼类洄游通道。黑水河流域松新坝址为了满足鱼类上行产卵修建了松新鱼道,然而作为洄游物种生命周期中的关键行为,鱼类下行洄游的需求也同等重要。为了寻求一种可行、高效、低损伤的下行过鱼方式,了解河流中不同环境因素对鱼类下行效率的影响,本研究在金沙江下游支流黑水河松新水电站补水通道开展鱼类下行过坝效果评估研究。针对两种鲤科鱼类(棒花鱼Abbottina rivularis和短须裂腹鱼Schizothorax wangchiachii)幼鱼和两种鳅科鱼类(短体副鳅Paracobitis potanini和红尾副鳅Paracobitis variegatus)幼鱼各放鱼90尾,定量分析鱼种、水体透明度、放鱼位置、流量、水温、水位等因素对鱼类下行效率的影响。结果表明:棒花鱼、短须裂腹鱼、短体副鳅、红尾副鳅的下行率依次为22.22%(20尾)、28.89%(26尾)、8.89%(8尾)、15.56%(14尾);幼鱼下行成功率与上游河道水温呈正相关趋势,且放鱼位置、鱼种、上游河道水温和流量均对鱼类下行成功率有显著影响。通过构建二元Logistic回归模型识...     

四川2015速度模型在九寨沟M_S7.0地震震源深度测定中的应用

利用四川2015模型,选择Msdp嵌入的几种常用定位方法对九寨沟M_S7.0地震进行重新定位,比较震源深度结果,并用PTD方法验证合适的震源深度,从而得到较为可靠的震源深度。本文最终判定九寨沟M_S7.0地震震源深度为12±2km。     

Removal of Cu(Ⅱ) from Wastewater Using Acidified Sewage Sludge Ash

Sewage sludge ash (SSA), the waste generated in sewage sludge incineration, was obtained from Wuhan Sewage Treatment Plant and used as a low-cost sorbent for removing Cu(Ⅱ) from wastewaters. The sorbent was first modified with 5 % sulfuric acid to increase its sorption capacity. The specific surface area, porosity, cation-exchange capacity (CEC) and pHZPC of the sorbent were measured. Batch experiments were made to study the effect of contact time, solution pH value and temperature on sorption. Both Langmuir and Freundlich models well described the Cu(Ⅱ) sorption process, with correlation coefficient (R2) values of 0.993 4 and 0.989 9 respectively. And the sorption process follows the Lagergren first order kinetic model. The equilibrium sorption capacity of acidified SSA to Cu(Ⅱ) is estimated to be 7.78 mg/g under optimal conditions.     

A modified ISBA surface scheme for modeling the hydrology of Athabasca River Basin with GCM-scale data

A soil–vegetation–atmosphere transfer model (SVAT), interactions between the soil–biosphere–atmosphere (ISBA) of Météo France, is modified and applied to the Athabasca River Basin (ARB) to model its water and energy fluxes. Two meteorological datasets are used: the archived forecasts from the Meteorological Survey of Canada’s Global Environmental Multiscale Model (GEM) and the European Centre for Mid-range Weather Forecasts global re-analysis (ERA-40), representing spatial scales typical of a weather forecasting model and a global circulation model (GCM), respectively. The original treatment of soil moisture and rainfall in ISBA (OISBA) is modified to statistically account for sub-grid heterogeneity of soil moisture and rainfall to produce new, highly non-linear formulations for surface and sub-surface runoff (MISBA). These new formulations can be readily applied to most existing SVATs. Stand alone mode simulations using the GEM data demonstrate that MISBA significantly improves streamflow predictions despite requiring two fewer parameters than OISBA. Simulations using the ERA-40 data show that it is possible to reproduce the annual variation in monthly, mean annual, and annual minimum flows at GCM scales without using downscaling techniques. Finally, simulations using a simple downscaling scheme show that the better performance of higher resolution datasets can be primarily attributed to improved representation of local variation of land cover, topography, and climate.     

自记水位仪的数字化改造

本文详细叙述了采用光电编码和微机技术对自记水位仪进行数字化改造的方案选择、理论计算和改造实践。     

Interaction of a river plume with coastal upwelling in the northeastern South China Sea

Observational and modeling studies were conducted to investigate the Pearl River plume and its interaction with the southwesterly driven upwelling circulation in the northern South China Sea during the summer. After exiting the Pearl River Estuary, the discharged freshwater generates a nearly stationary bulge of freshwater near the entrance of the estuary. Forced by the wind-driven coastal upwelling current, the freshwater in the outer part of the bulge flows downstream at the speed of the current and forms a widening and deepening buoyant plume over the shelf. The plume axis gradually shifts offshore of the current maximum as a result of currents induced by the contrasting density at the nose of plume and by the intensified Ekman drift in the plume. In this plume–current system, the fraction of the discharged freshwater volume accumulated in the bulge reaches a steady state and the volume of newly discharged freshwater is transported downstream by the upwelling current. Enhancement of stratification by the plume thins the surface frictional layer and enhances the cross-shelf circulation in the upper water column such that the surface Ekman current and compensating flow beneath the plume are amplified while the shoaling of the deeper dense water in the upwelling region changes minimally. The pressure gradient generated between the buoyant plume and ambient seawater accelerates the wind-driven current along the inshore edge of the plume but retards it along the offshore edge. Along the plume, downward momentum advection is strong near the highly nonlinear source region and a weaker upward momentum advection occurs in the far field over the shelf. Typically, the plume is shaped by the current over the shelf while the current itself is adjusting to a new dynamic balance invoked by the plume-induced changes of vertical viscosity and the horizontal pressure gradient. The spatial variation of this new balance leads to a coherent change in the cross-isobath transport in the upper water column during upwelling.     

大型射电望远镜背架精密安装技术

对65 m射电望远镜的背架安装做了尝试,取得较满意的结果.针对天线背架尺寸大、质量重、焊接变形大、几何精度要求高等特性,采用全站仪工业测量系统实现背架的快速、无接触、高精度定位测量,点位测量精度优于1 mm;采用独特的施工工艺和焊接技术,最大限度控制焊接变形,最终点位偏差优于1.5 cm.提出基于设计坐标系建立安装测量...     

地图设色系统中颜色转换模型的研究

本文详细地推导了由CRT上的颜色等色转换为YMC颜色方程,并给出了具体的形式及其结果。同时,对同包转换的条件进行了讨论,指出了颜色转换方程的适用条件,得到了一些有价值的结论。     

北斗卫星导航系统单频伪距绝对定位精度分析

利用北斗卫星导航系统进行导航定位具有全天候、高精度、不受其他定位系统限制等优点.为验证目前系统定位精度,采用单频伪距绝对定位的方式,对系统试运行阶段和正式提供区域服务后两天的观测数据进行处理和分析.结果表明:北斗系统单频伪距绝对定位能够达到米级精度,可以满足基础测绘和日常生产的需要.     

含矿预测的人工神经网络方法

运用神经网络模型的一典型模型——“反向传播”模型的改进形式,处理矿产资源统计预测问题,得出与数量化理论Ⅱ处理极为相似的结果.