Simultaneous Bromate and Nitrate Reduction in Water Using Sulfur‐Utilizing Autotrophic and Mixotrophic Denitrification Processes in a Fixed Bed Column Reactor          下载免费PDF全文

Sevgi Demirel  İbrahim Uyanık  Adem Yurtsever  Hakan Çelikten  Deniz Uçar 《洁净——土壤、空气、水》2014,42(9):1185-1189

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基于生态需水的石羊河北部平原生态保障技术研究     

程玉菲  王军德  李元红  金彦兆  胡想全 《冰川冻土》2014,36(3):724-731

针对石羊河流域日益严峻的生态环境问题,选择干旱区生态需水计算为切入点,以变异理论为基础,利用Mann-Kendall非参数检验的方法确定石羊河北部平原区地下水位恢复的目标年,用生态功能区划方法划分生态功能区,利用达西定律、阿维里扬诺夫公式计算了地下水恢复及生态目标条件下的生态需水量,并提出了相应的生态保障措施. 结果表明：石羊河北部平原区划分为5个生态功能亚区及16个三级区,地下水位恢复的目标年份为1977年,地下水恢复到1977年的生态需水量为 55.95×10⁸~74.10×10⁸ m³,2015年和2020年生态目标条件下的生态需水分别为1.66×10⁸ m³和1.80×10⁸ m³. 考虑到地下水恢复的缓慢性和现实性,建议优先考虑设定目标条件下的植被正常生长生态需水,其次通过继续压缩人均耕地面积和灌溉定额的方式保证地下水恢复.  相似文献   

Positioning requirements for the tsunami warning system     

F. E. Stephenson  T. S. Murty 《Marine Geodesy》2013,36(3-4):285-295

Abstract

Canada has increased the number of tsunami warning stations on the Pacific Coast from two to three. The last gauge was installed at the north end of Vancouver Island, thereby filling a large gap previously existing and providing full coverage along the coast. The record of gauges at two of the three locations is accessible either by telephone or by means of meteor burst communication, alleviating the difficulties experienced during the tsunami threat of May 6, 1986, when telephone communications were disrupted by heavy use. The gauge at Langara Island will be relocated in a more accessible and also a more tsunami‐responsive location at Rennell Sound in the Queen Charlotte Islands. All tsunami gauges also serve as tide gauges, recording the water level every 15 min. In the event of a tsunami, the recording interval can be altered to every 60 s. Suggestions have been made that Canada attempt deep‐sea recording of tsunamis off its Pacific Coast. Although this would be of great scientific value, no such program is contemplated at this time.  相似文献   

Spatial-temporal differences in in-stream flow requirement based on GIS： A case study of Yan＇an region,northern Shaanxi     

王丽霞  任志远 《地理学报(英文版)》2008,18(1):107-114

Although water has the central function of the bloodstream in the biosphere especially in arid or semi-arid regions such as Yah＇an region in northwestern China, yet the very limited attention is paid to the role of the water-related processes in ecosystem. In this research, based on continuous nearly 50-year data including runoff volume, sediment discharge as well as sediment accretion from hydrographic stations, and 10-year information of water quality from pollution monitoring stations, the method for measuring in-stream flow requirement has been put forward supported by experiential models and GIS spatial analysis. Additionally, the changes of in-stream flow requirement for environment and economic development have been addressed from spatial-temporal dimensions. The results show that： （1） According to the central streams in Yan＇an region, mean annual in-stream flow requirement reaches 1.0619 billion m^3, and the surface water for economic exploitation is 0.2445 billion m3 （2） Mean annual in-stream flow requirement for sediment transfers in flood period occupies over 80% of the integrated volume in a year. （3） From the 1950s to 1970s, in-stream flow requirement for sediment transfers is comparatively higher, while from the 1980s to 1990s, this requirement presents a decreasing tendency.  相似文献   

陕西关中地区水资源的可持续发展支持能力     

王菊翠  ;仵彦卿  ;党碧玲  ;胡安焱  ;杨磊  ;杨海燕 《西安地质学院学报》2009,(2):177-184

在阐述水资源支持能力涵义的基础上,计算了关中地区生态需水量、75%保证率时可利用水量、75%保证率时总需水量以及水资源支持能力的供需平衡指数。结果表明：关中地区生态需水量2005年为43.699×10^8m^3,2010年为44.119×10^8m,2015年为44.394×10^8m^3;2005年75%保证率时可利用水量为49.885×10^8m^3,2010年为49.466×10^8m^3,2015年为49.190×10^8m^3;2005年75%保证率时总需水量为94.26×10^8m^3,2010年为86.63×10^8m^3,2015年为84.22×10^8m^3。最后计算水资源支持能力的供需平衡指数,2005、2010、2015年,供需平衡指数小于0,说明流域可供的水资源量不具备对这样规模的社会经济系统的支撑能力,流域水资源对应的人口及经济规模是不可承载的,供需平衡的差值主要靠侵占河道内的生态需水量来实现的,河道内的生态破坏就是很好的证据。  相似文献   

高分卫星自然资源调查需求满足度评估     

郭丁  李姗姗  陈宗信  王力 《遥感学报》2022,26(3):579-587

当前高分对地观测数据应用来源众多,且其应用方式各异,如何对需求其进行规范化和结构化的需求综合及聚类,进而开展卫星观测能力对于用户需求的需求满足度进行评估,是当前高分对地观测系统建设及应用的关键.本研究基于层次分析法开展自然资源遥感调查的需求建模与评价研究,以可见光近红外类型的自然资源遥感调查需求为主要研究对象,提取自然...  相似文献   

地震活动图像分析预测汶川8．0级地震的回顾与思考   总被引：2，自引：1，他引：1  

黄圣睦  张永久  董瑞英 《四川地震》2009,(2):1-8

本文回顾了2008年5月12日四川省汶川8．0级特大地震前中长期及年度趋势预测过程。作者根据地震活动图像特征作出了较好预测,明确指出四川石棉-冕宁和汶川-松潘一带,2008年前后,可能发生7级以上地震。但带短期预测特点的2008年度大震危险性,作者没有作出确切的预测。本文思考了相关的经验教训并对改进分析预报工作提出了构想。  相似文献   

松嫩平原西部典型农田需水规律研究   总被引：18，自引：4，他引：14  

李取生  李晓军  李秀军 《地理科学》2004,24(1):109-114

采用联合国粮农组织最新推荐的模型方法(FAO56),利用近10年的日气象资料对松嫩平原西部玉米、大豆、高粱等作物近10年的农田逐日需水量进行了系统研究。得出了本区不同作物的需水规律,并根据当地的有效降雨量,获得了不同作物不同时段的水分亏缺规律,为节水灌溉和提高作物产量提供科学依据。  相似文献   

Assessment of reference evapotranspiration across an arid urban environment having poor data monitoring system     

Elham Shafieiyoun  Mahdi Gheysari  Mehdi Khiadani  Jahangir Abedi Koupai  Paria Shojaei  Mohammad Moomkesh 《水文研究》2020,34(20):4000-4016

Estimation of reference evapotranspiration (ET₀) in urban areas is challenging but essential in arid urban climates. To evaluate ET₀ in an urban environment and non-urban areas, air temperature and relative humidity were measured at five different sites across the arid city of Isfahan, Iran, over 4 years. Wind speed and sunshine hours were obtained from an urban surrounding weather station over the same period and used to estimate ET₀. Calculated ET₀ was compared with satellite-based ET₀ retrieved from the MOD16A2 PET product. Although MODIS PET was strongly correlated with the Valiantzas equation, it overestimated ET₀ and showed average accuracy (r = 0.93–0.94, RMSE = 1.18–1.28 mm/day, MBE = 0.73–0.84 mm/day). The highest ET₀ differences between an urban green space and a non-urban area were 1.1 and 0.87 mm/day, which were estimated by ground measurements and MODIS PET, respectively. The sensitivity of ET₀ to wind speed and sunshine hours indicated a significant effect on cumulative ET₀ at urban sites compared to the non-urban site, which has a considerable impact on the amount of irrigation required in those areas. Although MODIS PET requires improvement to accurately reflect field level microclimate conditions affecting ET₀, it is beneficial to hydrological applications and water resource managers especially in areas where data is limited. In addition, our results indicated that using limited data methods or meteorological data from regional weather stations, leads to incorrect estimation of ET₀ in urban areas. Therefore, decision-makers and urban planners should consider the importance of precisely estimating ET₀ to optimize management of urban green space irrigation, especially in arid and semi-arid climates such as the city of Isfahan.  相似文献   

中国对虾（Penaeus　chinensis）维生素营养的研究──Ⅴ．中国对虾维生素C营养   总被引：1，自引：0，他引：1  

徐志昌  刘铁斌  雷清新  李爱杰 《中国海洋大学学报(自然科学版)》1994,(3)

提出以稳定态的ＬＡＰＰ代替一般维生素Ｃ添加在配合饲料中饲喂对虾，指出：在１００ｇ饲料中含ＬＡＰＰ４００ｍｇ时，其体长增长率和体重增重率最高，存活率最佳．饲料中ＬＡＰＰ浓度大小影响对虾的蜕壳频率和蜕壳周期，当饲料中ＬＡＰＰ缺乏时，对虾的蜕壳频率降低，蜕壳周期延长；过量的ＬＡＰＰ也会使对虾的蜕壳频率相对降低，但比缺乏或不足的要高。维生素Ｃ在对虾肝胰脏中的积累以ＬＡＰＰ含量４００ｍｇ／１００ｇ饲料组为最高。  相似文献