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室内空气中甲醛的测定方法选择探讨 总被引:11,自引:0,他引:11
室内空气质量对人体健康的影响已成为社会普遍关注的重要环境问题之一,目前越来越多的检测实验室开始开展室内环境空气检测。本文通过对室内空气中甲醛测定不同方法的分析,选择了较为适宜的测定方法。 相似文献
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用离子束辅助沉积的方法在人工心脏瓣膜热解碳材料表面制备氧化钛薄膜,研究其对抗凝血性能的改善情况,以探索新型的人工瓣膜材料.对样本分别进行体外血小板黏附试验和动物体内试验以观察血栓形成的情况.结果表明,相比较传统的热解碳材料而言,氧化钛薄膜处理过的材料上黏附的血小板数目和聚集的血小板团数均明显减少,且血小板伪足数目亦明显减少.动物体内试验亦表明有氧化钛薄膜的样本表面形成的血栓较传统的热解碳材料要少,且没有热解碳材料表面有大量的血小板聚集和纤维蛋白形成.研究结果显示用离子束辅助沉积技术制备的氧化钛薄膜,其抗凝血性能优于目前临床应用的热解碳材料,很可能成为新一代的人工瓣膜材料。 相似文献
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Enzyme inhibitor screening by capillary electrophoresis with an on-column immobilized enzyme microreactor created by an ionic binding technique 总被引:2,自引:0,他引:2
A novel strategy for screening the enzyme inhibitors from the complex mixtures by capillary electrophoresis with an on-column immobilized enzyme microreactor created by an ionic binding technique is reported. The enzyme microreactor was prepared in two steps: First, the capillary wall was dynamically coated with a polycationic electrolyte hexadimethrine bromide (HDB) by simply flushing the column using the HDB solution. Subsequently, a plug of the enzyme solution was injected and incubated for 5 min to permit the enzyme molecules to immobilize on the positively charged coating via ionic binding. To demonstrate this strategy, angiotensin-converting enzyme (ACE) was employed as a model for the enzyme immobilization, inhibition study, and inhibitor screening. It has been proved that such a prepared immobilized ACE microreactor displays a high enough activity and stability. Furthermore, the immobilized enzyme microreactor could be easily renewed. The inhibition study or inhibitor screening was accomplished through the following procedure: (i) the substrate solution was injected and incubated within the microreactor for a short time span; (ii) subsequently, the voltage was applied to separate the product of the enzyme reaction from the unreacted substrate based on their different mobilities, the peak area of the product representing the enzyme activity; (iii) a certain amount of enzyme inhibitor or candidate compound was spiked into the substrate solution to assay the reduction of the immobilized enzyme activity. Thus, the inhibitors can be easily identified if the reduced peak area of the product is observed in electropherograms. Because the injection volume of the capillary was only 9.8 nL and the enzyme could be reusable, the assay cost could be dramatically reduced. The screening of a small compound library containing natural extracts and commercially available inhibitors was performed. The present approach has proved to be simple, rapid, and robust. 相似文献
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基于多采样率的频域倍频程研究 总被引:2,自引:0,他引:2
传统倍频程分析采用带通滤波器组算法实现,带通滤波器组算法仅能满足国家标准要求,并且用于分析分数阶倍频程时,滤波器组的数量及计算量成倍增长。提出了一种基于多采样率在频域分析倍频程及分数阶倍频程的算法。该算法首先对信号按通道重采样,并利用FFT转换到频域计算信号的倍频程及分数阶倍频程谱。仿真验证了算法的正确性,并与带通滤波器组算法做了比较。仿真及对比结果表明,相比于带通滤波器组算法,该算法能提供更好的谱分辨率,并且对于分数阶倍频程,该算法计算量明显少于滤波器组算法计算量。 相似文献
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冠脉内超声多普勒血流信号的极点特征 总被引:1,自引:0,他引:1
研究冠脉内超卢多普勒血流信号的极点特征,期望为微循环障碍等缺血性心脏病的诊断提供客观指标。先对冠脉内超声多普勒血流信号分段建立自回归滑动平均(Auto-regressive&moving-average,即ARMA)模型,获取一个心动用期信号的极点分布,计算极点分布的特征参数。通过分析18例冠脉内超声多普勒血流信号,得出若干个对冠脉微循环障碍敏感的特征参数。结果表明:冠脉内超声多普勒血流信号的极点特征参数,可以一定程度反映冠脉循环的状况。 相似文献