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总结了上海浦东机场二期飞行区3种不同组合的冲击碾压试验——冲击碾压联合高真空排水、冲击碾压联合塑料排水板、冲击碾压,试验结果表明,冲击碾压联合高真守排水方法压实效果最为显著,并在二期飞行区浅层地基处理实践中得到应用。 相似文献
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THEUTILIZATIONOFCHITINANDCHITOSANINDETERMINGTHECONTENTOFTRACECUPRICION测定铜含量的方法有多种,如二乙氨基二硫代甲酸钠,原子吸收分光光度法等。几丁质(缩写为CT)广泛地存在于动植物中,它是一种天然的大分子含氮多糖化合物,是β-1,4连接的乙酰氨基葡聚糖,它具有吸附离子的能力,能富集金属离子,故对水的净化具有应用潜力[1]。近年来国人对CT的研究日渐增多,在食品、医药、环保、农业、造纸、印染、日用化工以及酶制剂等方面,已陆续见诸报道。自然界甲壳质产量达100×108t,但实际用量仅2000t… 相似文献
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The Procellariiformes are the birds most affected by plastic pollution. Plastic fragments and pellets were the most frequent items found in the digestive tract of eight species of Procellariiformes incidentally caught by longline fisheries as well as beached birds in Southern Brazil. Plastic objects were found in 62% of the petrels and 12% of the albatrosses. The Great shearwater, Manx shearwater, Cory's shearwater and Antarctic fulmar were found to have greater quantities and frequencies of occurrence of plastic. There was no significant difference in the number of plastics between the birds from longline fisheries and beached birds. No correlation was found between the number of prey and number of plastics in the digestive tract of the birds analyzed, but this does not discard the hypothesis that, in some cases, the presence of plastic in the digestive tract has a negative effect on the feeding efficiency of these birds. 相似文献
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在对世界著名的维特瓦特斯兰德矿床成因讨论中,存在着2种主要观点:热液交代说和砂积成因说。后者经过补充、修改演变为改造砂矿成因说。最近,加拿大地质学家Reimer和Mossman代表后一种观点撰文,概括了近年来争论的焦点,回答了热液成因论者的质疑。 相似文献
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地下水中砷元素的形成及其控制因素 总被引:3,自引:0,他引:3
研究了长江中下游地区和吉林省地区地下水中砷元素形成和主要控制因素及其分布规律。结果表明,地下水中砷主要以H_3ASO_3、H_2AsO_4~-、HA_3O_4~(2-)等形式存在。它的形成和分布与含水介质及其上覆土层的砷含量、地下水的酸碱度、地下水的迳流条件、氧化还原环境、有机物质及铁锰等有密切的关系。 相似文献