共查询到20条相似文献,搜索用时 78 毫秒
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郑州位于淮河上游和黄河中原中心腹地,西依中岳嵩山,北临黄河,东接黄淮平原。素有"雄峙中枢、控御险要"之称,有"群贤毕至,逐鹿中原"之说。历史上曾是水旱码头,"西控虎牢,东蔽大梁","北通幽燕,南达湖广",以"九州腹地,十省通衢"而享盛名。曾有夏、商、管、郑、韩5朝为都,隋、唐、五代、宋、金、元、明、清8代为州。 相似文献
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《甘肃水利水电技术》2015,(2):45
冬天,为了预防剩余农药不良保管,造成人畜中毒或失效浪费,依诸多经验,农药冬季保管应注意“八防”。一要防事故。农药均有毒性,又有挥发性。应放在专柜或木箱内,外面加锁,贴上标签,专人管理。农药不可与粮、菜、饲料同室,更不宜与鞭炮、火药、机油、柴油、煤气等易燃易爆物放在一起,以免中毒、爆炸等事故发生。二要防挥发。乐果、敌敌畏、辛硫磷、虫螨腈、啶虫脒等液体农药容易挥发失效,造成空气污染。农户冬季保管这类农药时一定要把瓶盖拧紧,防止湿度、光照、温度等因素造成农药挥发。 相似文献
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针对太湖围湖造地遥感分析工程,提出了SPOT5遥感影像处理的的一般方法,并结合该项目重点介绍SPOT5遥感影像在太湖围湖造地、围网养殖遥感监测中的应用,为治理和维护太湖生态环境提供科学依据。 相似文献
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通过对远程监控技术在山东黄河引黄涵闸上的应用进行简要论述,对于山东黄河引黄涵闸远程监控系统的总体结构、主要功能、性能进行了介绍,分析了远程监控技术在山东黄河涵闸工程中的应用,提出了对引黄涵闸远程监控系统设计的看法. 相似文献
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在分析卫星遥感水深理论模式基础上,结合长江口水域的水沙特性建立了遥感长江口水深的分段模式,给出了相应的数字图像处理方法,所得到的遥感水深图与实测水深图较为一致. 相似文献
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近几十年来,我国的砂质、淤泥质海岸正呈现侵蚀加剧的演变趋向。随着卫星遥感数据在光谱、时间和空间分辨率方面的不断提高,海岸侵蚀和淤积监测具备了精度越来越高的数据源。在前人研究的基础上,以废黄河三角洲海岸为研究对象,利用遥感技术和野外实地调查对海岸岸线变迁及冲淤动态进行了研究。研究表明:遥感技术在岸线变迁、侵蚀淤积监测和预测方面具有其他技术无可比拟的优势,在海岸带地质环境监测中的应用已成为具有实用价值的技术。 相似文献
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应用软件是应用系统的核心.设计是否合理将直接影响应用系统的功能发挥。结合地下水埋深、降雨量远程遥测系统的研制,阐述了其应用软件的开发思路和处理方法,尤其是地理信息系统的引用,实现了报表的自动生成和等值线图自动绘制.拓展了系统功能,提高了水文“数字化”和数据处理“自动化”。 相似文献
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针对遥感影像中广泛应用的TIFF文件格式,文中提出了一种读取图像中任意多边形区域(数字流域模型中基本计算单元)灰度信息的方法,将灰度信息转换为水文参数信息,统计得出代表整个多边形的参数信息,写入数据库供模型调用,实现了遥感数据源与数字流域模型的无缝集成。 相似文献
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Phycocyanin (PC), as a characteristic pigment, is more suitable for monitoring cyanobacterial blooms and toxic cyanobacteria than chlorophyll-a (Chl-a). Because the absorption peak of PC is about ~620?nm, the application of remote sensing using a wavelength range of 615–630?nm becomes very attractive for the implementation of PC-targeted inversion algorithms. Numerous researchers have applied empirical and semi-analytical algorithms to derive PC concentration as proxies for cyanobacterial blooms. However, in contrast to Chl-a, the remote sensing estimation of PC concentration at the larger scale is still limited by the scarcity of data with sufficient spatial and spectral resolution. Therefore, this review attempts to provide a comprehensive overview of remote sensing techniques and retrieval algorithms as applied to the PC monitoring. The main emphasis is on the PC inversion algorithms and their realization via the available and perspective remote sensors. Based on the above analysis of state-of-the-art techniques and algorithms, the overall challenges and potentials of remote sensing-based cyanobacterial PC pigment retrieval are discussed in detail. 相似文献
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T. Kutser H. Arst S. Mäekivi K. Kallaste 《Lakes & Reservoirs: Research and Management》1998,3(1):53-66
In the years 1993, 1995 and 1996, passive optical remote sensing measurements taken on board ships or boats were carried out at 16 lakes in Estonia and five lakes in Finland, and also in some regions of the Baltic Sea. Simultaneously, the Secchi disk depth was measured and water samples were taken, from which chlorophyll a and suspended matter concentrations were determined in the laboratory. Using an Hitachi spectrophotometer, the attenuation coefficient spectra for filtered and unfiltered water were obtained, and the effective amount of yellow substance was estimated. The properties of the waters under consideration varied within rather wide limits, the Secchi disk depth changing from 0.4 to 8.5 m, chlorophyll concentration from 0.65 to 45 mg m?3 and the effective amount of yellow substance from 1.8 to 32 mg L?1. Applying the correlation method for interpretation of the optical remote sensing data, we derived algorithms for estimating the water properties in the Estonian and Finnish lakes and in the Baltic Sea. The correlation coefficients between remote sensing and other water characteristics are in the limits |r| = 0.61-0.84. This shows that despite difficulties caused by a small thickness of the‘informative’water layer and shadowing of the influence of some substance on the remote sensing spectrum by other substances in turbid, multicomponent waters, the passive optical remote sensing method is applicable for estimating the water transparency and quality in lakes and inland seas. However, the method is not suitable for (i) determining the value of a very small amount of some substance in the water if the concentrations of other optically active substances are remarkably higher or for (ii) investigating the water-bodies with a large amount of yellow substance, where extremely strong absorption of light in the water leads to an‘abnormal’shape of the remote sensing reflectance spectra. Our results confirm also that remote sensing algorithms derived for the open ocean waters are in most cases not applicable for lakes and inland seas. 相似文献