排序方式: 共有33条查询结果,搜索用时 15 毫秒
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提出了强拟Armendariz环的概念,给出了强Armendariz环和强拟Armendariz环上的一些结果. 相似文献
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怀菊花中微量铁的测定 总被引:5,自引:3,他引:2
为探讨邻二氮菲分光光度法测定怀菊花中微量元素铁含量的可行性,怀菊花的药理功效、食用营养价值与微量元素含量可能存在的关系,根据铁离子与特定显色剂显色产生可见吸收,采用混合酸y(HNO3):V(HClO4)=4+1对怀菊花样品湿法消化处理,在pH2~9的溶液中试剂与铁生成稳定的橙色络合物,并用分光光度法测定了怀菊花中微量元素铁含量。结果表明,所选的怀菊花中铁含量303.9~337.9μg/g,加标回收率为90.2%~100.6%。分光光度法操作简便、干扰离子少,测量快速、结果准确度和灵敏度高,易推广和 普及使用。 相似文献
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L.L. Ji A. Pukhov E.N. Nerush I.Yu. Kostyukov K.U. Akli B.F. Shen 《The European physical journal. Special topics》2014,223(6):1069-1082
Interaction of laser plulses with intensities up to 1025?W/cm2 with overdense plasma targets is investigated via three-dimensional particle-in-cell simulations. At these intensities, radiation of electrons in the laser field becomes important. Electrons transfer a significant fraction of their energy to γ-photons and obtain strong feedbacks due to radiation reaction (RR) force. The RR effect on the distribution of laser energies among three main species: electrons, ions and photons is studied. The RR and electron-positron pair creation are implemented by a QED model. As the laser intensity inreases, the ratio of laser energy coupled to electrons drops while the one for γ-photons reaches up to 35%. Two distinctive plasma density regimes of the high-density carbon target and low-density solid hydrogen target are identified from the laser energy partitions and angular distributions of photons. The power-laws of absorption efficiency versus laser intensity and the transition of photon divergence are revealed. These show enhanced generation of γ-photon beams with improved collimation in the relativistically transparent regime. A new effect of transverse trapping of electrons inside the laser field caused by the RR force is observed: electrons can be unexpectedly confined by the intense laser field when the RR force is comparable to the Lorentz force. Finally, the RR effect and different regions of photon emission in laser-foil interactions are clarified. 相似文献
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Crystallography Reports - The microstructure and mechanical properties of three experimental compositions of a new heat- and corrosion-resistant cast cobalt-based alloy have been investigated. It... 相似文献
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丝瓜中维生素C含量的测定 总被引:1,自引:0,他引:1
为建立丝瓜中维生素C含量直接测定的新方法,以10%盐酸溶液为溶剂,采用紫外分光光度法测定其含量。结果表明,维生素C在0~10 mg/L质量浓度范围内与吸光度呈良好的线性关系,回归方程为:y=0.047 46ρ+0.001 09,r=0.999 7。检出限为0.023μg/mL,加标回收率在90.6%~99.0%之间。该法操作简单,结果准确,应用于维生素C含量的测定,结果准确,令人满意,可作为控制维生素C质量的方法。 相似文献
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建立了非紧FC-空间中新的连续选择定理,作为应用,获得了非紧FC-空间中广义模糊约束多目标对策的弱Pareto平衡存在定理.我们的结论统一、改进和推广了一些近期文献的已知结果. 相似文献