In general , bu is used to negate non - verbs , zero - valent verbs and monovalent verbs , while though fu is often used to negate bivalent verbs and trivalent verbs , bu can also be used to negate these two verb types 一般说来，非动词、零价动词、一价动词要用不来否定，而二价动词、三价动词常用弗来否定，但也可以用不来否定。
This paper introduced the remediation on contamination with chlorinated organics in water and soil by zero - valent iron on the latest research results at home and abroad , discussed the mechanism and research state of the zero - valent iron remediating contamination with chlorinated organics , and analyzed the development trend in the field 摘要介绍了零价铁修复水土中含氯有机污染物的机理及目前国内外最新研究成果及现状，并分析了该研究领域的发展方向。
Through the flux / retention experiments it was shown that when the applied pressure rises , both volume flux and rejection increase , too ; and that the higher the feed salt concentration , the lower rejection and volume flux . the charged mosaic membranes could permeate mono - valent and bi - valent inorganic salts , but reject the low - molecular - weight organics . furthermore , sem was used to observe the surface and the cross section of the composite membrane 另外，膜性能表征结果显示:随着操作压力的增加，膜通量及膜对电解质的截留率均趋增加;而随着原料液浓度的增加，通量和截留率都有所降低;膜对低分子有机物和无机电解质混合体系(如:亚硝基红盐与naci混合体系;蔗糖与nazso ;混合体系等)的选择性较高，能实现其有效分离。
