新型浮子式水位计平衡器

经过几年的努力,我局于2001年试验成功一种实用的新型浮子式水位计平衡器(也称斜井式水位计),主要用于对水库、闸坝、江河等水位观测站斜坡测井水位的测量,设计新颖,可供水文行业同仁借鉴参考。1 设计思想 通常采用的浮子式水位计感应装置由圆筒型浮子、平衡锤、吊挂钢索以及水位轮构成,测量水位需建造一个垂直竖井,利用浮子与平衡锤的升降,进行水位测量。但在水库等测量地点建井成本很高(有时可达数十万元甚至上百万元)。如果采用斜坡测井,而水位计不加以改造,则需建造一个垂直的     

斜井式激光水位测量装置

斜井式激光水位测量装置,为特殊条件下水位测量提供一种新的采集传输手段。介绍了斜井式水位装置的工作原理,并从浮子的设计、激光测距仪的安装、信号控制转换器、装置的可维护性等4个方面分析了实现斜井式水位测量的可用性,并通过实际应用,剖析了斜井式激光水位测量装置的技术优势和应用前景。目前＂斜井式激光水位测量装置＂已广泛用于水库、江河、湖泊等新建水位遥测站中,具有很好的推广价值。     

柘溪水电站集水井水位控制的自动化改造

湖南省柘溪水电站从发电至今厂内排水系统自动化建立共经历了浮子式水位控制、电极式水位控制以及现在的新型吹气式水位控制三个阶段。综合运行情况分析: 浮子式水控制有它的一大特点:即水位波动不影响它正常控制排水泵的启停。第一年运行正常,到了第二年以后就不那么理想了。究其原因,就是由于水质差,油污泥将浮子活动部件卡位,使它的上、下可动部件失去一定的灵活性。另外,有时因厂家质量问题,浮子密封不良,造成绝缘不好,还有的浮子里渗有少量的油水,使排水系统失灵。 电极式水位控制与浮子式水位控制相比又有它的特点:它不但不受水位波动对它正     

激光测距仪在水位测量中的应用

介绍了悬挂式水位测量装置的原理,并从浮子的设计、激光测距仪的安装、信号控制转换器、装置的可维护性等4个方面,分析了悬挂式水位测量装置的科学性,介绍了其在湖北清江水情自动测报系统中的应用情况,指出了悬挂式激光水位测量装置的技术优势和适用场合。     

雷达波自动测流系统设计与应用

人工方式水文测流工作效率低、时效性差、安全风险大、成本高。因此,开发无人值守自动测流系统十分必要。基于自动化控制理论开发了自动测流系统。系统以非接触式雷达波流速仪作为水面流速测验传感器,利用简易双轨缆道将雷达波流速仪移动到设定垂线水面上方施测水面流速,同时实时采集水位数据,实现了河道水位、流量的实时自动监测。该系统可全过程自动控制测流,具备较强的差错控制能力和良好的系统辅助管理能力,很好地解决了无人值守条件下中小河流、山区性暴涨暴落河流流量自动测验的难题。     

浮锤分管式水位测井制作与安装

引言 随着计算机技术、通讯技术、传感器技术的广泛应用,越来越多的防洪工程、灌排工程以及水文测站采用水位自动化监测设备。目前在水位自动化监测系统中多采用轴角编码器的浮子式水位传感器(俗称“码盘”),该设备虽然具有受水质与气候环境影响小、价格低廉、稳定可靠、使用维修方便、无温漂时漂和掉电记忆等特点,但是安装使用却需要建水位测井,并要求采取一定的防浪措施,方能消除波浪的影响;另外,它的水位测井是将浮子和平衡重锤放在同一管内,因而管     

一种轨道式渠道自动测流系统的研制与应用

针对引黄灌区缺少适用面广、使用方便的量水系统的问题,提出了一种轨道式灌区明渠量水方法。结合PLC自动化技术、计算机及无线数据传输技术,通过系统集成的方法,研制了包括渠道断面自动测流车和远程控制管理软件的轨道式渠道断面自动测流系统。该系统可测量水位、水深、分层流速等多个参数,通过内置模型自动计算断面流量,使用GPRS无线网络将测量数据上传到控制软件,同时具备自主充电、自动启闭测流房卷帘门等功能,实现了真正意义上的无人值守和全自动测量。经在部分引黄灌区渠道比测试验,该系统流量测量结果与流速仪精测法的测量结果相比,误差在2%以下,满足灌溉渠道系统量水规范的要求。与传统的明渠量水系统相比,该系统具有效率高、适用性强、精度高等特点。     

高精度浮子式水位传感器设计

文章讨论了浮子式水位传感器实现高精度水位测量过程中碰到的问题及解决的方法。在高精度浮子式水位传感器的设计中，采用绝对值光电轴角编码器准确记录水位变化引起的轴角度变化，通过高性能单片机，完成对轴角编码器、环境温度的采样、多种校正因子的计算、数据显示和通信功能，实现对水位数据的自动精确测量。     

常用水位传感器的比较和选择

总结常用的浮子式、压力式、超声波式、雷达式、激光式水位传感器的基本工作原理和主要优缺点,从设备的测量精度、测量量程、可靠性、所需配套土建、运行维护等方面对常用水位传感器进行相互比较,总结在实践中水位传感器选择的一些经验,提出水位传感器的选择应遵守可靠、精确、经济的先后原则。     

新型浮子式水位计的研制与应用

为解决目前传统浮子式水位计受水位波动影响易打滑、自身系统误差大、使用不便等问题,设计了一种新型浮子式水位计.新型浮子式水位计机械部分采用上下轮的封闭式结构,改进浮筒与重锤的设计,降低测绳与转轮打滑的可能性,提高了测量准确性;电路部分采用光电编码器,及以低功耗单片机 MSP430F247为基础的水位数据采集装置,为用户提供了方便的人机接口及丰富的通信方式,进一步提高了产品的实用性.     

地下厂房施工过程的三维非线性数值模拟分析

根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。     

Evaluation of freshwater mussel relocation as a conservation and management strategy

The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects.     

基于模型试验的河床砂砾石层基本特性研究

为了经济可靠地确定深厚覆盖层的基本特性参数,以大渡河双江口水电站坝基河床砂砾石层基本特性研究为工程背景,进行大尺寸模型试验,研究河床砂砾石层的旁压模量和动探击数随密度、级配以及上覆压力的变化规律。根据室内模型试验结果,结合现场旁压试验及钻孔试验成果,推断出坝址区河床砂砾石相关层位的密度,并依此进行砂砾石室内力学试验,获得设计所需力学参数。研究成果可为深厚覆盖层基本特性测试提供新的方法。     

基于BP神经网络-马尔科夫链模型的隧道围岩位移预测

在隧道工程施工中,围岩位移预测起着很重要的作用。将BP神经网络-马尔科夫链模型引入到隧道围岩位移预测中来,通过对训练样本的学习,利用BP神经网络实现了对位移时间序列的滚动预测,同时得到了实测值与预测值的相对误差;在此基础上利用马尔科夫链对相对误差进行修正,有效地提高了预测结果的精度。并将该模型应用于某公路隧道拱顶下沉位移时序预测中,结果表明该模型具有精度高、科学可靠的特点,为隧道围岩变形的预测提供了新的途径。     

Short communication. Pipelines as a refuge for freshwater snails

In the lower River Murray, Australia, populations of gastropods have declined markedly over the past 40 years. Of the native fauna of about 18 species, only the ancylid Ferrissia petterdi remains common (but in patches), and another five species feature in sporadic local resurgences. Until recently the viviparid Notopala was thought to be extinct. The introduced physid Physa acuta is widespread, but in low numbers. The decline probably is associated with flow regulation, high turbidity and the introduction of common carp. Snail populations have persisted, however, in irrigation pipelines fed from the river, where they periodically cause blockages. This paper reports the discovery of the only known populaion of Notopala hanleyi in a pipeline where the inner wall accumulates microbial and other organic matter, providing high quality food for snails. In the Murray before regulation most of the periphytic biomass was probably microbial, as fluctuating water levels would have maintained littoral communities in a highly productive, early state of succession his postulated that, by stabilizing seasonal water levels, regulation has promoted the production of filamentous green algae, an inferior food source, and so displaced snail populations from the open aquatic environment.     

浙江省水域调查录入系统的设计和应用

浙江省水域调查录入系统将调查数据与电子地图相整合,对分类水域数据进行统计计算,并对输入数据进行合理性和完整性检查,得到调查范围内现有水域的详细数据,实现了水域调查数据输入、计算、统计和查询的数字化管理,提高了工作效率和工作质量,为各地下阶段水域保护规划编制和水域管理工作提供了数据支持。对该系统的设计原则、功能和技术设计等作了介绍。     

基于CT-连续加荷水泥乳化沥青混凝土细观损伤规律研究

利用CT技术对水泥乳化沥青混凝土的细观损伤过程进行实时扫描观测,获得了混凝土试件在连续加荷下的CT图像。通过采用直观分析法、CT数分析法、CT数与损伤变量关系3种方法分析表明,水泥乳化沥青混凝土的破坏过程可分为压密、扩容、裂纹扩展、破坏4个阶段,同时混凝土在受压过程中具有韧性,在极限荷载之前各断面处于压密和微扩容的强化阶段,极限荷载之后混凝土从损伤到破坏发展比较平稳。     

浅谈天湖水电站水轮机运行故障及处理措施

简述天湖水电站投运以来各种故障的表现形式，分析其原因，提出了相应的处理方法及措施，并对合理利用国内外设备提出建议。     

Fish assemblage response to recent mitigation of a channelized warmwater stream

Various designs of low‐head dams are used to rehabilitate streams or forestall upstream channel incision after channelization. We report on the efficacy of using notched sills and grade control structures (GCS) to restore the fish assemblage in Luxapallila Creek, Mississippi. We tested the null hypotheses that habitat variables and species richness, evenness, and assemblage structure would not differ among: (1) a channelized segment with no modifications; (2) a channelized segment mitigated by the installation of sills and GCS; (3) a segment upstream of the installations and undergoing channel incision; and (4) an unaltered segment. Although habitat variables changed, neither species richness, evenness, nor fish assemblage structure differed between mitigated and channelized segments with both exhibiting less richness and different assemblage structures than the unaltered segment. Lack of differences in species richness between the incised and unaltered segments suggest that the GCS may have halted the negative effects of upstream channel incision before species were extirpated. Conspicuous habitat differences between the altered (channelized and mitigated) and unaltered segments were lack of backwaters and canopy coverage and finer substrates in the altered segments. Our results suggest a more comprehensive rehabilitation strategy is required in Luxapallila Creek. Published in 2003 by John Wiley & Sons, Ltd.     

NUMERICAL STUDY OF WAVE EFFECTS ON SURFACE WIND STRESS AND SURFACE MIXING LENGTH BY THREE-DIMENSIONAL CIRCULATION MODELING

1. INTRODUCTION Coastal and continental shelf regions are characterized by intensive interaction between wave and current. These regions are of great economic significance to mankind. Therefore, the modeling of wave and current as well as their mutual int…