基于正切模型的额济纳绿洲生态需水研究

基于RS解译和实测径流资料,分析了额济纳绿洲生态状况与水资源的关系,结果表明,无论从时间尺度上还是从空间尺度上,额济纳绿洲生态演变和水资源之间均具有明显的正相关关系,水资源减少是生态退化的决定性因素。在此基础上,结合西北内陆河产水和用水特点,提出了产流较弱的绿洲区生态需水量是为维持一定规模绿洲所需区外补给水量这一观点,并建立了额济纳绿洲生态需水计算的“正切”模型,通过与其他方法的比较,验证了模型的合理性,该方法可为北方缺水地区绿洲生态需水分析计算和水资源管理方案的合理制定提供决策依据。     

黑河额济纳绿洲地表水与地下水的关系

在分析额济纳绿洲水资源组成的基础上,研究了地表水和地下水的时空分布特征。结果表明:地下水埋深随地表径流量的增加而加大,地下水埋深的变化滞后于地表径流量的变化。根据绿洲生态需水的特点,从定性和定量上研究了地表水与地下水的关系,经回归分析提出了定量关系表达式。     

额济纳地区绿洲恢复生态需水量研究

在现有研究的基础上,再度明确了生态需水量的涵义;通过对干旱地区植被生态需水量现有计算方法的分析,考虑植被盖度对生态需水量的影响,提出了计算干旱地区天然植被生态需水量的新方法;在对额济纳绿洲现状分布特点分析的基础上,综合考虑绿洲恢复规模和生态功能之间的关系,提出了额济纳绿洲恢复的若干方案,应用所提出的生态需水量计算方法对各方案生态需水量进行计算,并以研究区未来可利用水资源总量为约束,确定了额济纳绿洲未来的恢复方案。     

黑河下游地下水变化规律及共生态影响

通过对多年实测资料的系统分析,总结了黑河下游地下水变化规律;给出地下水与地表水之间的关系提出"灌溉农业型"、"稳定绿洲型"、"荒漠绿洲型"地下水埋深变化曲线的概念,这些概念对干旱区水资源配置具有重要的参考意义.依据这些规律,说明了地下水埋深变化对生态演变、水资源管理的影响,进而对额济纳绿洲演变、生态需水等重要问题,阐述了作者的观点.     

额济纳绿洲植被生态需水及其估算

生态需水是当前水问题的一个研究热点,对于生态环境急剧恶化的内陆干旱区,这一研究尤为紧迫。以额济纳绿洲为例,依据GIS技术进行生态分区并且采用阿维里扬诺夫估算方法,对其1998年和2004年的生态需水量进行了计算。结果表明:当植被生态系统结构发生变化时,其相应的需水量也发生变化,额济纳绿洲植被1998年和2004年的最低生态需水量分别为5.8494×108m3和5.9083×108m3。不同时期生态需水的定量计算和定性分析,对科学制定生态恢复方案和水量分配方案具有很大的现实意义和借鉴作用。     

黑河下游地下水变化规律及其生态影响

通过对多年实测资料的系统分析，总结了黑河下游 地下水变化规律；给出地下水与地表水之间的关系；提出“灌溉农业型”、“稳定绿洲型”、“荒漠绿洲型”地下水埋深变化曲线的概念，这些概念对干旱区水资源配置具有重要的参考意义。依据这些规律，说明了地下水埋深变化对生态演变、水资源管理的影响，进而对额济纳绿洲演变、生态需水等重要问题，阐述了作者的观点。     

西北干旱区额济纳绿洲水资源与生态环境保护对策

分析黑河流域下游额济纳绿洲水资源与生态环境的关系 .由于流域中、上游地区用水量逐年增加 ,使上游来水量逐渐减少 ,导致额济纳河由常年流水变成季节性流水 ,造成额济纳绿洲地下水位持续下降、水质恶化、植被退化、土地沙漠化 ,以及沙尘暴危害加剧 ,使绿洲生态环境严重恶化 .为保护和恢复额济纳绿洲 ,使社会经济可持续发展 ,应采取一系列生态环境保护对策 ,包括实施流域水资源分配 ,合理配置水资源 ;加强节约用水 ,发展高效农业 ,提高水资源利用率 ;搞好生态环境建设及水源保护 ,搞好流域规划 ,加强水资源管理和基础研究等工作 .     

民勤绿洲水资源调度管理模型的建立

民勤绿洲水资源调度管理模型以各种水资源开发利用、经济社会发展、生态环境保护为目标,以水资源供需平衡模拟为核心,预测各计算单元各行业不同时间尺度的需水量和需水过程,考虑水资源系统中各种水源的供水过程,通过分析进行水资源调度方案的优化选择。民勤绿洲水资源调度管理模型的核心模块是水资源实时调度模块,另外还包括种植结构优化、需水预测、可供水量预测和结果评价4个子模块。将该模型与利用FEFLOW 5.4构建的地下水数值模拟模型进行耦合,通过地下水位模拟预测各方案对地下水位和生态环境的影响,评价调度方案的合理性。     

新疆干旱区流域生态需水问题研究

生态需水是当前干旱区流域水资源管理的重要问题。通过对新疆平原区荒漠和绿洲两种生态系统的分析,特别是对天然绿洲生态系统中人工绿洲水资源利用方式及过程的分析,尝试性提出生态需水量在流域规划和水资源管理中的定位、不同生态系统的保护方式和基本生态水量的确定方式,并简述了新疆奎屯河流域以生态退水作为恢复流域生态水量的实例。     

荒漠绿洲植被生态需水研究现状及发展趋势——以民勤县为例

以民勤荒漠绿洲现状条件为基础,通过总结国内外相关研究成果,明晰了以植被生长为主体的生态需水内涵。从生态系统的适宜性、阈值性、循环性和农业气象原理入手,分析了植被生态需水的理论基础,藉此提出适宜民勤绿洲的生态需水估算方法,即依托于3S技术划分土地类型及面积,以潜水蒸发法为主,综合使用直接计算、Penman-Monteith公式等多种计算方法。此外,探讨了植被生态需水研究的难点所在,认为应将重心放在建立植被生长与降雨量、地下水埋深等因素的响应函数,探究潜水与SPAC系统的耦合机制,揭示植被生态需水机理。构建符合民勤荒漠绿洲的植被类型和水文生态条件适宜程度识别指标体系,探究植被生态需水驱动机制,最终实现统筹人口、资源、环境与经济社会的协调可持续发展。     

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。     

Automated system for removal and pneumatic transport of fly ash from electric precipitator hoppers

A system for removal and pneumatic transport of fly ash is examined, in which air pulses act on batches (pistons) of ash formed in a duct. Studies are made of the effect of several physical parameters on the force required to displace a piston of ash and these serve as a basis for choosing a system for removal and pneumatic transport of ash simultaneously from several hoppers of an electric precipitator. This makes it possible to separate the ash particles according to size without introducing additional components. Formulas are given for calculating the structural and dynamic parameters of this system and measurements of indirect dynamic parameters are used to calculate the input-output characteristics of the system. In order to optimize the system, configurations for summing several ducts into a single transport duct for pneumatic ash transport are proposed. Some variants of dry ash utilization and the advantages of producing of size-separated particles are considered. __________ Translated from élektricheskie Stantsii, No. 2, pp. 26–30 (2008).     

The flood pulse advantage and the restoration of river-floodplain systems

The ‘flood pulse advantage’ is the amount by which fish yield per unit mean water area is increased by a natural, predictable flood pulse. Evidence for this increase is presented from tropical and temperate fisheries. It is argued that increasing multispecies fish yield by restoring the natural hydrological regime is consistent with increasing production of other trophic levels and with restoration from ecological and aesthetic viewpoints. When applied to a river-floodplain system, this restoration would provide a large, self-sustaining potential for recreation, commercial exploitation, and flood control. An interim ‘natural flood pulse’ restoration approach is proposed for systems modified for navigation. This approach approximates the natural hydrological regime in a river reach and is intended as a first step in the long process of restoring the watershed.     

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。