排序方式: 共有156条查询结果,搜索用时 31 毫秒
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卷烟主流烟气中挥发性醛酮和苯的P&T-GC分析 总被引:2,自引:0,他引:2
挥发性羰基化合物和苯是卷烟烟气中重要的有害物质,为此建立了P&T-GC法测定卷烟样品主流烟气中的乙醛、丙醛、丁醛、丙酮、2-丁酮和苯.该方法不用2,4-二硝基苯肼(DNPH)衍生化,不用有机溶剂萃取和浓缩,减少了对环境的污染,具有灵敏度高、检出限低、定量准确、操作简便等特点.结果表明:方法有较好的重复性,相对标准偏差在5.39%以下;检出限为0.85 ng/支~6.55 ng/支;6种物质的回收率在89.22%~98.21%之间. 相似文献
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Let X be a Banach space and Ф be an Orlicz function. Denote by L^Ф(I,X) the space of X-valued (I)-integrable functions on the unit interval I equipped with the Luxemburg norm. For f1,f2,... ,fm ∈ L^Ф(I,X), a distance formula distv(f1,f2,... ,fm,L^Ф(I,G)) is presented, where G is a close subspace of X. Moreover, some existence and characterization results concerning the best simultaneous approximation of L^Ф (I, G) in L^Ф (I, X) axe given. 相似文献
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BoLingGUO GanShanYANG 《数学学报(英文版)》2004,20(6):1135-1152
We prove the existence of solutions of the static Landau-Lifshitz equation with multidirect effective field and with Dirichlet boundary condition, and establish the stability of the solution of Landau-Lifshitz equation with respect to time. 相似文献
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Lin Yuan Wenzhong Huang Kun Zhou Yuede Wang Wei Dong Gang Du 《Natural product research》2015,29(20):1914-1919
Two new butyrolactone derivatives, terrelactones A and B (1 and 2), together with four known butyrolactone derivatives (3–6), were isolated from the fermentation products of the fungus Penicillium oxalicum 0403. Their structures were elucidated by spectroscopic methods, including extensive 1D and 2D NMR techniques. The anti-tobacco mosaic virus (anti-TMV) activities of 1 and 2 were evaluated. The results showed that compounds 1 and 2 exhibited high anti-TMV activity with inhibition rates of 25.5% and 27.4%, respectively. The inhibition rate is close to that of positive control (28.9%). 相似文献
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Jiang-Yuan Zhao Jian-Hai Ding Zheng-Hui Li Tao Feng Hong-Bin Zhang 《Natural product research》2018,32(8):972-976
Three cyclic dipeptides (1–3), including one new compound (1) were isolated from cultures of the basidiomycetes Coprinus plicatilis. Their structures were elucidated by spectroscopic methods, including extensive 2D NMR techniques. At the same time, all compounds were tested for their cytotoxicities against five human cancer cell lines. 相似文献