大坝安全自动监测系统设计的若干问题

本文对大坝安全自动监测系统的准备（包括资料收集和现场调研）以及设计过程中的几个问题进行了探讨，强调了系统设计应注重实用和以具体大坝现场情况为基础的观点。     

怀柔水库大坝测压自动监测系统

大坝扬压力（或大坝测压管水位）等技术参数是监测坝体安全的重要指标，历来均用人观测，怀柔水库大坝安全监测系统采用了现代通信和计算机技术，选用高可靠元器件的传感器，使大坝安全监测自动化，可大大提高大坝观测的工作效率，减轻劳动强度，该系统投入运以来，设备运行安全可靠。     

大坝监测自动化中的人工比测研究

阐述了人工比测的概念、方式和数据分析方法,对人工比测及数据分析中应注意的问题也进行了深入研究。     

流量自动监测比测率定分析

流量自动监测是实现水文监测现代化的关键,而流量自动监测比测率定是流量自动检测的重要环节。从流量比测率定准备、工作要点、精度评价、报告编制等方面对流量自动监测率定进行全过程分析,为流量自动监测率定实践提供参考。     

黄河水质监测采样器比测实验研究

为了贯彻实施SL219—98《水环境监测规范》．对黄河水质监测中在用的积时式、瞬时式、简便式现场采样器进行比测实验，确定不同采样器的采样精度，掌握其使用的连续性和互换的可能性．找出适用黄河的采样器，最终达到规范采样程序、提高监测质量的目的。     

水文自动测流系统误差计算及比测成果分析

近年来水文缆道自动测流系统得到较快的普及应用。文中通过对白马寺水文站缆道自动测流系统比测试验资料的分析,根据误差传播理论,肯定了缆道自动测流系统的流量测验精度,为实现水文缆道自动测流提供了可靠依据。     

实现大坝安全监测系统自动化应注意的问题

从技术、经济、维护等方面分析了实现大坝安全监测系统自动化时应注意的问题：自动化系统相对人工观测具有省时省力的优点，但也具有费用高、易受潮湿及电磁干扰等环境影响，同时维护要求严，出现故障修复难度大的缺点，因此在决定是否需要实现自动化时，要根据具体情况进行分析。     

大坝安全监测中的若干问题

分析了大坝安全监测的目的、要求、前期工作、内涵，指出了大坝安全监测中存在的问题。文章认为对大坝安全监测工作，运行管理单位必须特别重视，同时设计、科研单位也应随着新情况的不断出现对大坝安全监测进行研究，有针对性地开发新型监测技术，完善风险分析和紧急预案，以确保大坝的安全。     

山西省汾河灌区供水对策研究

介绍了汾河灌区近年来的供水基本情况,并探讨制定了灌区在丰水年、平水年和枯水年的供水方案,为灌区建设和管理提供参考意见。     

对小浪底水库首次人工塑造异重流的探讨

为了有效控制水库泥沙淤积的数量,改善库区泥沙淤积的形态,从而延长水库的使用寿命,小浪底水库于2004年首次进行了人工扰动塑造异重流试验。结果表明:异重流冲沙前后库尾泥沙淤积形态和数量的变化明显,认为利用人工塑造异重流进行水库冲沙是可行的。     

ADCP多线积深式流量测验技术应用研究

以往ADCP进行河道断面流量测验的应用方式是走航式,多沙河流存在"动底",影响底跟踪应用并给流量测验结果带来较大误差。采用多线积深式流量测验方法,利用ADCP依次对多条垂线进行流速流向、水深测量,测记起点距计算总流量,并在黄河中游吴堡、府谷两站开展了与流速仪法的流量比测试验,对资料进行了分析和评价,说明多线积深式流量测验方法作为低沙、平水期流量测验的一种应用方式,可缩短历时,提高测报技术水平,具有较好的应用前景。     

Drying Temperature Effects on Fish Dry Mass Measurements

Analysis of tissue composition in fish often requires dry samples. Time needed to dry fish decreases as temperature is increased, but additional volatile material may be lost. Effects of 10°C temperature increases on percentage dry mass (%DM) were tested against 60°C controls for groups of lake trout Salvelinus namaycush, rainbow smelt Osmerus mordax, slimy sculpin Cottus cognatus, and alewife Alosa pseudoharengus. Lake trout %DMs were lower at greater temperatures, but not significantly different from 60°C controls. Rainbow smelt and slimy sculpin %DMs were lower at greater temperatures and differences were significant when test temperatures reached 90°C. Significant differences were not found in tests using alewives because variability in %DM was high between fish. To avoid inter-fish variability, 30 alewives were each dried successively at 60, 70, 80, and then 90°C and for all fish %DM declined at each higher temperature. In general, %DMs were lower at greater temperatures and after reaching a stable dry weight, fish did not lose additional mass if temperature remained constant. Results indicate that caution should be used when comparing dry mass related indices from fish dried at different temperatures because %DM was negatively related to temperature. The differences in %DM observed with rising temperature could account for substantial portions of the variability in reported energy values for the species tested. Differences in %DM means for the 60 vs. 80°C and 60 vs. 90°C tests for rainbow smelt and alewife could represent of from 8 to 38% of observed annual energy cycles for Lakes Ontario and Michigan.     

人工和自动化监测资料的融合前提与方法研究

大坝安全监控中,同一监测量常有人工和自动化两组监测数据。为更加合理准确地分析评价大坝的安全状况,提出将人工与自动化两组监测数据融合为一组监测数据的想法,并对两组数据的融合前提和融合方法进行了研究。实例分析表明,在满足融合前提时,相关的融合方法较好地解决了人工与自动化监测资料的融合问题,为大坝安全监控提供了真实、客观的资料。     

浅谈人工挖孔桩的设计与施工

结合龙滩水电站及长洲水利枢纽的工程实践,介绍人工挖孔桩的主要设计要点和施工技术要点,可供类似工程参考.     

GPS基线向量解算的人工干预方法

GPS观测中,由于种种原因信号中往往包含噪声。介绍了通过人工干预剔除包含噪声的信号,获得良好的基线向量解的方法。论述了信号取舍方法和基线取舍的原则。根据内业解算发现的问题,为外业观测提供了经验。     

导坑式人工挖孔托换桩技术

导坑式人工挖孔托换桩技术目前应用还较少,在现行的相关规范中还尚未专门涉及。全面介绍此种技术的特点、设计计算方法以及施工和监测方法,并结合成功的实例,在西北黄土地区既有建筑物的地基基础加固中得到了很好的检验。展示了该工艺的实际应用效果。更多还原     

Lagrangian Measurements in Lake Ontario

Satellite-tracked trajectories of 19 drifters involving six experiments between 1983 and 1989 in Lake Ontario were analyzed. Three aspects of the observed motions at 3.5 m depth are examined: (1) the spatial structure of the mean and variance velocity fields, (2) the Lagrangian statistics (dispersion and eddy diffusion characteristics) of the variance field based on single-particle analysis, and (3) the Eulerian statistics of the fluctuating velocity field. The spatial structure of the mean velocity field is consistent with that obtained from dynamic height and current meter measurements. The lake circulation is cyclonic. A coastal jet with mean speed in excess of 11 cm/s dominates the mean circulation. The jet is most intense along the southern shore. Two recirculation zones are observed in the western part of the lake. The current variability is strongly anisotropic in the coastal zone. Away from the coastline, the flow is quasi-isotropic.The theory of single-particle diffusion by homogeneous random motion (Taylor 1921) describes the dispersive motions reasonably well. In the western part of the lake, zonal scales greatly exceed the meridional scales while in the eastern part of the lake they are similar. In the western part of the lake, the zonal and meridional integral time and length scales and eddy dijfusivities are, respectively, (T₁₁,T₂₂) = (17.2, 5.5) hr, (L₁₁,L₂₂) = (10.1, 2.1) km and (K₁₁,K₂₂) = (16.5, 2.2) × 10⁶ cm²/s. In the eastern part of the lake, these values are (T₁₁,T₂₂) = (7.9, 14.7) hr, (L₁₁,L₂₂) = (1.7, 2.7) km, and (K₁₁,K₂₂) = (1.1, 1.5) × 10⁶ cm²/s. The presence of inertial oscillations does not affect the diffusivity estimates. The eddy kinetic energy of single-particle motion in the western part of the lake is 189 cm²/s² which is about six times that of the eastern part. The Eulerian decorrelation scales tend to be larger than those of the single-particle estimates. The space scales indicate that the eddy field is quasi-isotropic.