共查询到20条相似文献,搜索用时 46 毫秒
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鸡心、鸡血中抗氧化物的提取及其活性研究 总被引:2,自引:0,他引:2
从鸡心、鸡血中提取抗氧化物 ,并分别利用邻苯三酚 (PR)自氧化法、碘量法对其活性进行了检测。结果表明 :鸡心提取物比鸡血提取物的抗氧化活性强。 相似文献
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以水杨醛、乙二胺为原料,在碱性条件下,经优化反应条件,合成了双水杨醛缩乙二胺,并在此基础上选取合适的碱金属元素锌作为中心离子反应,优化反应条件,合成新型Schiff base型配位化合物荧光显现剂。利用元素分析确定目标产物化学式,并利用红外光谱对产物结构进行了表征。合成指纹荧光显现剂在特定波长激发下具有理想的荧光效果,有利于后期的开发和实践运用,并在其他领域也具有广泛应用。 相似文献
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光稳定剂复配对核壳WPC抗紫外老化性能的影响 总被引:1,自引:0,他引:1
为探索经济、环保且效果更好的木塑复合材料(WPC)表面耐老化处理方法,采用共挤技术,以不同复配方式将纳米白炭黑、HALS–L944及UV327添加于核壳型WPC壳层。对试样进行紫外光加速老化试验,并对其弯曲性能、表面颜色及化学成分结构进行了测试表征与方差分析。研究结果表明,当壳层加入1%纳米白炭黑与1%UV327复配时效果最好,紫外老化2 500 h后,较之空白样,WPC的弯曲强度保留率提高了14.7%,弹性模量保留率提高了17.4%,保护效果最好,具有一定的协同作用;表面颜色变化较为缓慢,色差下降了44.9%,优于单独添加光稳定剂效果;O/C值增长幅度为9.1%,氧化的碳/未氧化的碳比值增加了11.8%,表面氧化程度最低。说明纳米白炭黑与UV327具有一定的协同作用,能够更好地提高核壳WPC的抗紫外老化性能,降低其光氧化降解程度。 相似文献
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Marta Zaleskaya-Hernik ukasz Dobrzycki Marcin Karbarz Jan Romaski 《International journal of molecular sciences》2021,22(24)
In contrast to monotopic receptor 3, the anthracene functionalized squaramide dual-host receptor 1 is capable of selectively extracting sulfate salts, as was evidenced unambiguously by DOSY, mass spectrometry, fluorescent and ion chromatography measurements. The receptors were investigated in terms of anion and ion pair binding using the UV–vis and 1H NMR titrations method in acetonitrile. The reference anion receptor 3, lacking a crown ether unit, was found to lose the enhancement in anion binding induced by the presence of cations. Besides the ability to bind anions in an enhanced manner exhibited by ion pair receptors 2 and 4, changing the 1-aminoanthracene substituent resulted in their exhibiting a lower anion affinity than receptor 1. By using receptor 1 and adjusting the water content in organic phase it was possible to selectively detect sulfates both by “turn-off” and “turn-on” fluorescence, and to do so homogenously and under interfacial conditions. Such properties of receptor 1 have allowed the development of a new type of sensor capable of recognizing and extracting potassium sulfate from the aqueous medium across a phase boundary, resulting in an appropriate fluorescent response in the organic solution. 相似文献
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It was the best measure of color rendering, it was the worst measure of color rendering. Color rendering index (CRI) is the most common metric used by the lighting industry to represent the color rendering properties of electric light sources. CRI was intended to characterize how “true” or “natural” objects appeared when illuminated by a light source, but was never intended to, for example, represent how well object colors could be differentiated under a light source, another important aspect of color rendering. Data presented here demonstrate that CRI in conjunction with another measure of color rendering, gamut area index (GAI), is useful at predicting subjective judgments of how “natural” objects appear as well as how “vivid” objects appear, and how well one can discriminate between subtle differences in hue. Neither measure by itself, however, is sufficient for meeting all of the expectations of a light source for providing good color rendering under all viewing conditions. It remains for future research to determine if just two metrics are sufficient to assure good color rendering from a light source and whether these two metrics (CRI and GAI) are the best for such purpose. In the meantime, CRI and GAI should be used jointly in recommendations as practical, useful, and mutually reinforcing measures of color rendering. The data presented here also demonstrate that total irradiance is important for good color rendering. © 2008 Wiley Periodicals, Inc. Col Res Appl, 33, 192–202, 2008 相似文献