排序方式: 共有37条查询结果,搜索用时 5 毫秒
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麦斛细胞毒活性成分研究 总被引:5,自引:0,他引:5
利用硅胶、聚酰胺柱层析等分离方法, 从麦斛全草的乙醚萃取物中分离得到4个化合物, 经化学方法和光谱分析(UV, IR, NMR, MS)鉴定为3,4,7-三羟基-2-甲氧基菲(1), 2,5-二羟基-4-甲氧基菲(2), eugenitin (3)和2,5-二羟基-4-甲氧基-9,10-二氢菲(4), 其中1为新化合物. 采用MTT法分别测得化合物1和2对体外培养的人急性髓性白血病细胞和人肝癌细胞增殖的抑制活性, 并分别考察了增敏剂葛根素对化合物1和2增殖活性的协同作用. 相似文献
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This paper establishes a model of a nonlinear diode refrigerator consisting of two diodes switched in the opposite directions and located in two heat reservoirs with different temperatures.Based on the theory of thermal fluctuations,the expressions of the heat flux absorbed from the heat reservoirs are derived.After the heat leak between the two reservoirs is considered,the cooling rate and the coefficient of performance are obtained analytically.The influence of the heat leak and the temperature ratio on the performance characteristics of the refrigerator is analysed in detail. 相似文献
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In this paper, a mathematical model with respect to the optimalidentification of the thermodynamic parameters is established. The identifiabitity of the dynamics problem is proved and necessary conditions of the optimality are given. 相似文献
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提出了高效液相色谱法测定联苯菊酯悬浮剂中联苯菊酯含量的方法。样品用甲醇超声提取20min,分取部分提取液用流动相溶液,即甲醇与水(87+13)的混合溶液定容为100mL。用针头过滤器净化并取出此溶液,通过Agilent Eclipse XDB-C_(18)色谱柱,并用上述流动相溶液进行分离,流量为1.4mL·min~(-1),于206 nm波长处用二极管阵列检测器检测。联苯菊酯的质量浓度在3.0~50.0mg·L~(-1)范围内与其峰面积呈线性关系,方法的检出限(3S/N)为0.67mg·L~(-1)。在11.1,15.5,24.4mg·L~(-1)三个添加水平下,回收率在99.2%~104.5%之间,相对标准偏差(n=6)在0.8%~2.9%之间。 相似文献