排序方式: 共有34条查询结果,搜索用时 472 毫秒
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甘草试样用硝酸和过氧化氢在Mars型微波消解仪中进行处理,用电感耦合等离子体质谱法测定试样中6种微量元素(镍、铅、铬、镉、砷、硒)的含量。用动态反应池技术消除质谱测定中的多原子离子光谱干扰。在优化试验条件下,方法的检出限(3s)在0.013~0.12μg.L-1之间。方法用于灌木枝叶标准物质中微量元素的测定,测定值与认定值相符。 相似文献
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Nonlinear dynamical stability of gap solitons in Bose-Einstein condensate loaded in a deformed honeycomb optical lattice 下载免费PDF全文
Hongjuan Meng 《中国物理 B》2021,30(12):126701-126701
We investigate the existence and dynamical stability of multipole gap solitons in Bose-Einstein condensate loaded in a deformed honeycomb optical lattice. Honeycomb lattices possess a unique band structure, the first and second bands intersect at a set of so-called Dirac points. Deformation can result in the merging and disappearance of the Dirac points, and support the gap solitons. We find that the two-dimensional honeycomb optical lattices admit multipole gap solitons. These multipoles can have their bright solitary structures being in-phase or out-of-phase. We also investigate the linear stabilities and nonlinear stabilities of these gap solitons. These results have applications of the localized structures in nonlinear optics, and may helpful for exploiting topological properties of a deformed lattice. 相似文献
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在承受初条件和冲击载荷的多自由度阻尼系统中,本文利用振型叠加法对激发高频振动的机理进行了研究,并对工程实例进行了电算和分析. 相似文献
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催化动力学光度法测定痕量铁 总被引:10,自引:0,他引:10
论文研究和建立了催化动力学褪色光度法测定痕量Fe(Ⅲ)的新体系,反应介质为盐酸-邻苯二甲酸氢钾(pH2.2)缓冲溶液,催化体系为痕量Fe(Ⅲ)催化过硫酸铵氧化邻甲氧基酚的自聚反应。研究了此反应体系的最佳条件、动力学参数及反应机理,考察了21种干扰离子的影响,建立了一种新型催化动力学光度法测定痕量Fe(Ⅲ)的方法。本法的线性范围0.07~1.1μg·(25mL)~(-1)。方法灵敏度远远高于普通光度法,检出限为5.4×10~(-8)g·L~(-1)。方法应用于自来水、河水、城市污水、豆奶粉和茶叶中痕量Fe(Ⅲ)的测定,相对标准偏差为0.36%~3.4%,标准加入回收率为97.3%~102.7%,结果满意。 相似文献
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研究了一类带干扰(布朗运动)的对偶风险模型,此模型可以用来模拟证券公司的盈余过程(经营收入).利用无穷小分析法,求出了公司在破产前总分红现值期望函数(分红函数)满足的微积分方程组,导出了与该微积分方程组等价的更新方程组.最后,在指数分布收入情形下,我们给出了分红函数在特例下的一般解. 相似文献
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The doping effect of Cu on the self-assembly film of melamine on an Au(111) surface has been investigated with scanning tunneling microscopy (STM). The evaporated Cu adatoms occupy the positions underneath the amino groups and change the hydrogen bonding pattern between the melamine molecules. Accordingly, the self-assembly structure has changed stepwise from a well-defined honeycomb into a track-like and then a triangular structure depending on the amount of Cu adatoms. The interaction between Cu adatom and melamine is moderate thus the Cu adatoms can be released upon mild heating to around 100℃. These findings are different from previous observations of either the coordination assembly or the physically trapped metal adatoms. 相似文献
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研究了一类在安全负载体系下进行赋税且按照门槛策略进行分红的对偶风险模型.分析了此模型破产前折现分红的期望,得到了其满足的积分方程、积分-微分方程和相关的表达式.最后,在特例Erlang(2)分布下给出了一般解. 相似文献
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将烟草样品粉碎至40目,以1,4-丁二醇为内标,甲醇为萃取溶剂,超声萃取60 min后,以气相色谱-质谱/选择离子监测(GC-MS/SIM)法测定1-丙醇、二甘醇、三甘醇、丙二醇和丙三醇的含量。结果表明:目标化合物在1~100μg/mL范围内线性关系良好,方法的检出限为0.05~0.48μg/mL,回收率为90.2%~103.7%,相对标准偏差(RSDs)为0.9%~3.0%。方法的前处理简单、灵敏度高、定性定量准确,适用于烟草中多元醇的定性定量分析。 相似文献
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