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Hydroxyl radical (•OH) can cause severe damage to cells and tissues. However, its analysis is very difficult for its high reactivity and very short life. This paper present a HPLC-MS/MS method for indirectly detecting •OH by determining DMPO-OH, its addut with spin trap DMPO ( 5,5-dimethyl-1-pyrroline N-oxide ), with the N-Methyl-2-Pyrrolidone (NMP) used as internal standard. The ratio of the peak area of the DMPO-OH and NMP negatively correlate with the concentration of •OH. The results show that the method is simple, rapid, precise in both the determination of •OH and evaluation of •OH scavenging activities of antioxidants. 相似文献
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Antimony-doped tin hydroxide colloid precipitates were prepared by hydrolysis of SnCl4·5H2O and SbCl3 ethanol solutions. Isoamyl acetate was selected as azeotropic drying solvent and was compared with the most commonly used n-butanol solvent on treating precipitate for low hard agglomeration precursor powders. The FT-IR, BET, XRD, and TEM results of the precursor powders and calcinated antimony-doped tin oxide powders were recorded. The results demonstrate that isoamyl acetate is an excellent azeotropic drying solvent that can effectively prevent the agglomeration of particles and greatly improve the fluffiness of the obtained dried powders. After these precursor powders are calcined, antimony-doped tin oxide nanopowders with tetragonal futile structure and high dispersivity can be obtained. 相似文献
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“还原失真”和“还原失效”是变化条件下水资源评价中的棘手问题之一。本文提出基于物理参数的分布式水文模型用于变化环境下水资源评价的原理和假定,以及基于此的UCMV(Up-reach for Calibration and Mid-reach for Validation) Process水资源评价方法。以永定河山区流域为实例,进行了不同时期下垫面的水资源评价。结果表明,流域1990年代和2000年代下垫面条件下多年平均地表水资源量分别为10.799亿m3和9.892亿m3,后者相对于前者产流能力降低了8.0%,清楚地表现出下垫面变化对流域产流能力的影响,也进一步证实了“还原失效”现象的存在以及基于物理分布式水文模型进行变化环境下的水资源评价的有效性。 相似文献
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关于做好新形势下女干部培养选拔工作的思考 总被引:1,自引:0,他引:1
培养选拔女干部是建设高素质干部队伍的重要组成部分,也是实现男女平等、构建社会主义和谐社会的必然要求。社会主义市场经济体制的不断完善,既使妇女面临比以往任何一个时代更加严峻的挑战,又为其施展才华提供了更多的机遇。要制定培养选拔使用女干部的措施,必须认清形势,分析有利条件和困难,根据女性成长规律,创新工作方法,切实把优秀的妇女干部培养选拔出来。 相似文献
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