共查询到20条相似文献,搜索用时 62 毫秒
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阐述了南金水库基本情况,对土坝的坝顶高程进行了重新复核并对其进行了渗流稳定计算和坝坡稳定计算,对溢洪道采取了维修加固处理,对输水洞采取了拆除重建处理。 相似文献
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水利水电工程建设运行对水资源、水能资源的开发利用,改变了人类的生活,促进了城市建设,保障了人们的用水、能源需求,但对水文的影响是显著的。文章用河道来水距平百分率旱涝定义方法对四川省凉山彝族自治州尼日河流域旱涝特征进行了分析;并用梯度排列系列数据预测方法对尼日河流域旱涝进行了预测研究。通过对尼日河流域旱涝预测的研究,量化了其上游水利水电工程对旱涝预测影响的程度,并为消除影响提出了解决办法。 相似文献
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抽水蓄能机组工况运行对发变组保护的影响 总被引:1,自引:1,他引:0
抽水蓄能机组一般有10多种运行工况,不同的工况对发变组保护的要求也不同.文中通过对不同工况的分析,对相关联的几种特殊发变组保护进行了分析探讨,对发电机开关失灵保护、相序保护、差动保护进行了分析,指出了保护盲区的补救措施;对工况的取用形式进行了分析,提出了对工况组合进行优化设置的观点,并探讨了不同工况下保护开放/闭锁逻辑的重要性. 相似文献
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对机组的润滑油系统进行了介绍,在此基础上,对因主油箱油位测量引发的一起误停机事故进行了分析,对故障进行了检查,提出了处理方案,避免了事故再次发生。 相似文献
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杨炬敏 《河南水利与南水北调》2009,(6):71-72
文章对水工钢筋混凝土的裂缝进行了详细分析,并对钢筋混凝土裂缝的容许值进行了适用性分析,最后对钢筋混凝土裂缝的处理提出了技术性措施建议,为水工钢筋混凝土的施工及运行提供了依据。 相似文献
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介绍了西易杰旺露天煤矿概况,分析了该矿地下含水层及隔水层的地质情况,根据露天煤矿开采对地下水资源的影响机理,对该煤矿开采对地下水资源的影响进行了评价,并提出了减少煤矿开采对地下水资源影响的一些措施。 相似文献
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具有不同来流形式的Rayleigh-Benard对流特性 总被引:1,自引:0,他引:1
主要研究了在二维矩形腔体中,不同条件对Rayleigh-Benard对流时空结构影响.首先分析了没有水平流速作用下,Rayleigh-Benard对流的对流特性;其次,分析了具有水平流速作用下的Rayleigh-Benard对流的特性;最后,分析了在变调流速作用下,Rayleigh-Benard对流的特性.总结得出对流结构的动力学特性和时空结构. 相似文献
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对嘉兴地区主要给水厂近年来应用立体弹性填料、LT型悬浮球填料、YS型悬浮填料、卵石填料等的生物预处理工艺从填料及配套设施、工艺运行参数、运行效果、成本等方面进行了比较.认为弹性填料生物预处理更适用于低浊(50 NTU以下)、低氨氮(1.5 mg/L以下)原水,LT型悬浮球填料生物预处理适用于低中浊(100 NTU以下)、低中氨氮(2.5 mg/L以下)原水,YS型悬浮填料生物预处理及"SAF"滤池对低浊、中高氨氮(2.5 mg/L以上)原水有较好的适应性.最后探讨了弹性填料存在的短流、积泥,悬浮填料存在的部分填料流化不均匀,富氧的生物工艺单元内水生动物泛滥等问题. 相似文献
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Changes in nutrient levels in some Eastern European rivers in response to large-scale changes in agriculture. 总被引:3,自引:0,他引:3
P St?lnacke S M Vandsemb A Vassiljev A Grimvall G Jolankai 《Water science and technology》2004,49(3):29-36
Since the late 1980s, the use of commercial fertilisers in most Eastern European countries has decreased at an unprecedented rate. We examined the impact of this dramatic reduction in agricultural inputs on concentrations of nutrients in four rivers in Eastern Europe: the Emajogi and Ohnejogi (Estonia), the Daugava (Latvia), and the Tisza (Hungary). Time series of nitrate (NO3-N) and phosphate (PO4-P) concentrations and data on runoff were selected to represent catchments with substantial areas of agricultural land and available time series of sufficient length and frequency. The study period was 1987-1998. We detected downward trends in nitrate-N and phosphate-P in only two of the four rivers. Our results imply that the response to the extensive decrease in agricultural intensity since the late 1980s has been slow and limited in many rivers. Corresponding results in the literature are inconclusive and comprise several examples of both decreasing and non-decreasing nutrient concentrations. Our findings, along with similar data from other studies, indicate that large cuts in nutrient inputs do not necessarily induce an immediate response, particularly in medium-sized and large catchment areas. Moreover, the difference we noted between nitrogen and phosphorus suggests that factors other than reduced fertiliser application influenced the inertia of the water quality response. 相似文献
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对长江、珠江等河口及其近海水域缺氧现象与影响因素进行研究,结果表明,主要分布于长江与珠江河口及其邻近海域的缺氧现象,夏季(6—8月)达到最盛,秋冬季消失;长江口的缺氧区域主要位于30.75°N~32°N,122.5°E~123.25°E附近海域,具有南北2个缺氧中心;珠江口缺氧程度相对较轻,缺氧区域主要在广州黄埔区河段至虎门水域和伶仃洋;辽河、钱塘江、海河等河口区域也时而出现零星的缺氧现象;水体缺氧受控于多项环境要素,物理层化作用是缺氧产生的最初诱因之一,陆源污染物的分解则是重要的耗氧负荷;各河口区特征各异,潮汐、洋流、营养盐、叶绿素a等要素对缺氧区的范围、程度和持续时间影响程度不一。 相似文献
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深圳河支流新洲河属雨源型河流,因污染而采取全线截排污水整治.在上游河道内利用生物飘带技术处理低浓度污水,处理达标后,作为河流生态水源.在中游将截排污水引入自然循环方式污水处理系统,处理达标后作为河道补水.下游利用射流清淤配合利用天文大潮进行水体交换,达到消除黑臭水体,维持河道水景观的目的.介绍新洲河水环境综合整治采用的几项关键技术的设计原理及应用效果. 相似文献
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李广杰 《水科学与工程技术》2001,(5):7-8
洋河水库是我省重点病险库之一,1998年12月实施除险加固工程。工程建设过程中在科研、设计、施工及管理等方面取得了可喜的成果。通过研究分析,因地制宜地选择了天然建筑材料,合理确定了施工方案,有效保证了施工质量,节约了工程投资。 相似文献
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Ecological river engineering can be defined as the design and implementation of river works and river restoration works for the benefit of human society. It also guarantees the sustainable ecological functions of a river, such as its habitats and self-purification of its water. It is currently in the beginning stages in Korea, utilizing scientific knowledge on the processes of aquatic ecosystem degeneration and a methodology for solving the ecological problems in artificially altered rivers currently under development. The changes in river management and work practices in Korea may be best explained with a chronologically progressing sequence of ‘Natural’, ‘Disaster-prevention’, ‘Occupied’, ‘Park’, and ‘Close-to-nature’ rivers. Since the 1960s, the focus on river management and work has shifted from flood control only, to both flood control and riverine habitat conservation and restoration. Five research topics have been selected for this article, and the progress of each research area is briefly described with a representative picture in each topic. They are as follows: (1) flow resistance due to vegetation, (2) environmental flow, (3) floodplain vegetation modeling, (4) small dam removal, and (5) river restoration. For the future prospects of research on ecological river engineering in Korea, a necessity of further research on floodplain vegetation recruitment and succession, which can explain the so-called ‘white river’ and ‘green river’, is underlined, among others. Finally, two ongoing large research programs on river ecosystem restoration, of which are sponsored by the Government of Korea, are briefly introduced, followed by the introduction of a near-prototype experiment facility recently completed mainly for research on ecological river engineering. 相似文献