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驾驭斑图(pattern)的新方法——空间微扰法 总被引:1,自引:0,他引:1
提出了一种控制斑图(patern)的新方法———空间微扰法.以一个光学系统为例,用这一微扰法成功地稳定、选择和跟踪了不稳定的卷形、方形和六角形斑图.这一具有普适性的新方法极易被应用到实际空间延展非线性系统中. 相似文献
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本文报道了用单分子磁镊研究抗癌药顺铂导致的DNA凝聚过程.结果表明,当拉力比较小时,DNA凝聚的长度-时间曲线是连续缩短和阶跃缩短并存的复杂曲线.而当拉力较大但又不足以阻止DNA的凝聚时,凝聚曲线为连续缩短的双曲线.增加顺铂浓度只会增大凝聚速度而不会改变反应曲线的形状.实验结果与下列成环凝聚模型一致:在水溶液中顺铂能够与DNA形成双臂加合物,也能形成单臂加合物.当顺铂使DNA长链上相距较远的碱基间发生远程交联时,形成小环,导致DNA凝聚.小环间的进一步交联会引起DNA的完全凝聚.DNA凝聚产物十分稳定.
关键词:
顺铂
DNA凝聚
单分子操纵
抗癌药 相似文献
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By using magnetic tweezers, atomic force microscope and mass spectrometry, we study the effects of pH on oxaliplatin-induced DNA condensation, the DNA persistence length, the amounts of micro-loops and of oxaliplatin bound to DNA. It is found that the DNA condensation degree, the amounts of micro-loops and of oxaliplatin bound to DNA increase with the decrease in the pH value while the DNA persistence length has an opposite behavior. The observed effects may be related to the drug resistance of cancer cells. 相似文献
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Transverse spatial modulation of beam profiles for a probe beam counterpropagating to a pump beam in a 45°-cut BaTiO3:Ce crystal with an externally applied electric field is studied numerically studied. For the case that the direct ion of the external field makes an angle of 45° with the c-axis of the crystal, the probe beam, which propagates in the direction perpendicular to the external field and has a waist wider than that of the pump beam, can acquire deep spatial modulation. In contrast, the pump beam shows no spatial modulation but diffracts only. For the case the external field is directed opposite to the direction mentioned above, the probe beam shows much stronger spatial modulation as compared to the pump. 相似文献
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