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Is Precipitation the Dominant Controlling Factor of High Inorganic Nitrogen Content in the Changjiang River and Its Mouth? 总被引:1,自引:1,他引:0
沈志良 《中国海洋湖沼学报》2003,21(4):368-376
The main reasons for the high content of inorganic N and its increase by several times in the Changjiang River and its mouth during the last 40 years were analysed in this work. The inorganic N in precipitation in the Changjiang River catchment mainly comes from gaseous loss of fertilizer N, N resulting from the increases of population and livestock, and from high temperature combustions of fossil fuels. N from precipitation is the first N source in the Changjiang River water and the only direct cause of high content of inorganic N in the Changjiang River and its mouth. The lost N in gaseous form and from agriculture non-point sources fertilizer comprised about 60% of annual consumption of fertilizer N in the Changjiang River catchment and were key factors controlling the high content of inorganic N in the Changjiang River mouth. The fate of the N in precipitation and other N sources in the Changjiang River catchment are also discussed in this paper. 相似文献
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光学后向散射法在海洋现场探测无机悬浮颗粒物质的应用研究 总被引:1,自引:0,他引:1
本文论述了使用作者于1988年研制成功的国内第一台拖曳荧光计系统,通过改换荧光测量滤片为中性滤光片。 相似文献
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1INTRODUCTIONInrecentyearsglobalclimatechangehasbeenanissueofbothpublicandscientificconcern.Oceanscover71 %ofearthandplayamajorroleinglobalclimatechange.Phosphorus,asacriticalelement,regulatespri maryproductioninaquaticecosystems.Therefore,thefunctionofphosphorusinoceansystemhasreceivedin creasingscientificinterest(Songetal.,2 0 0 3 ) .PP (particulatephosphorus)isanimportantforminphosphorustransferinseawater(Song,2 0 0 1 ) .Pro portionofPPintotalphosphorus(TP)inseawatervar iesfrom 1 0 … 相似文献
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In the process of combustion of coal organic and inorganic materials in it will undergo a complex variation.Part of thew will become volatiles and,together with coal smoke,enter into atmosphere,some will remain in micro-particulates such as ash and dust and find their way into atmosphere in the form of solid particles,and the rest will be retained in ash and slag.Coal ashes are the residues of organic and inorganic substances in coal left after coal combustion and the compostition of coal ashes in dependent on that of minerals and organic matter in coal.This paper deals with the chemical composition of coal ashes,the distribution of trace elements in them and their petrological characteristics,and also studies the relationship between the yield of coal ashes and the distribution of trace elements.In addition,a preliminary study in also undertaken on the factors that affect the chemical composition of coal ashes.As viewed from the analyses of coal ash samples collected from the Yanzhou mining district,it can be seen clearly that coal ashes from the region studied are composed chiefly of crystalline materials,glassy materials and uncombusted organic matter and the major chemical compositions are SiO2,Al2O3,Fe2O3,and CaO,as well as minor amounts of SO3,PWO5,Na2O,K2O and TiO2.During the combustion of coal,its trace elements will be redistributed and most of them are enriched in coal ashes.At the same time,the concentrations of the trace elements in flying ash are much higher than those of bottom ash,i.e.,with decreasing particle-size of coal ashes their concentrations will become higher and higher.So the contents of trace elements are negatively proportional to the particle-size of coal ashes.There has been found a positive correlation between the trace elements Th.V.Zn,Cu and Pb and the yield of coal ashes while a negative correlation between Cl and the yield of coal ashes. 相似文献
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海水中无机物的光化学反应 总被引:5,自引:0,他引:5
综述了近几十年来国内外关于海水中无机物的光化学反应的研究状况。首先,阐述了海洋光化学在海洋科学中的重要性,历年来的发展状况以及海水的光化学与其它相关领域之间的相互影响作用。其次,本文分别从阴离子的光化学反应,阳离子的光化学反应和过氧化氢的光化学反应三个方面对海水中无机物的光化学反应进行了论述,详细介绍了铁、锰、铜、汞、过氧化氢、硝酸盐和碘化物随反应介质、温度、酸碱度、有机物浓度和光照等外界因素的不同而发生的光化学反应的变化。另外,讨论了上述物质发生光化学反应的主控因素及其在反应过程中对周围环境的影响作用,并对部分物质的反应机理作了介绍。最后,本文指出了这一研究领域存在的问题和不足,并提出今后的研究建议。 相似文献