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The accumulation and absorption kinetics of La by fish ( Oozias latipes) from both water and food were tested in fresh water. The effects of La concentration in water and food and the existence of fulvic acid on the absorption were investigated. It was demonstrated that the amount of La accumulated in fish increases with the increase in La concentration in water and food and exposure duration, which the normal physiological activity of fish was inhibited. With fulvic in the system, the absorption rate decreases significantly indicating that the fulvie combined La is not available to the fish uptake. 相似文献
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本文用仪器中子活化法测定珠穆朗玛峰科学考察队(1966~1968年)在珠穆朗玛峰地区各垂直分带(2030~5480m)所采集的不同类型土壤样品(共14个剖面,44种样品)中28种元素。 1.分析方法 1) 标准和样品的制备 本工作用USGS的标准岩石AGV-1直接作为多元素标准。采用美国NBS的标准参考物质——煤(SRM-1632a)作为As和Br的标准;Ni、W、U和Zr则用人工合成标准。样品和标样各称取30~40mg左右,分别用高纯铝箔包好备用。 2) 照射 样品和标准用铝箔紧密包在一起,在清华大学游泳池型反应堆的活性区照射10~20小时,中子通量~1.3×10~(13)n·cm~(-2)·s~(-1)。 相似文献
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Inthepastyears ,mostoftheapplicationsofREEsinagriculturewerebasedonfoliagedressing .Recently ,REEswithotherfertilizersaredressedintosoildirectlyasbasicfertilizer .GenerallysoildressingamountofREEsistentimeshigherthanfoliagedressingamount .Re searchesdeali… 相似文献
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N—甲基吡咯烷酮的生产及市场 总被引:3,自引:0,他引:3
对N-甲基吡咯烷的生产工艺路线进行了比较,介绍它在工业中的应用,并分析了其市场前景。 相似文献
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