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991.
朱宗波 《中国无机分析化学》2018,8(4):51-55
通过对铅捕集贵金属原理的研究,首次提出铅覆盖再次富集的概念,建立了高品位金泥中金、银的检测方法。以经典火试金法测得的金银含量为准确值,计算金泥直接灰吹对金银的回收率,探讨了铅箔用量、称样量、灰吹温度和铅箔覆盖方式对金银回收率的影响,获得了高品位金泥直接灰吹的最佳工艺条件。在最佳工艺条件下,对氰化-置换得到的高品位金泥进行直接灰吹法与火试金方法对比试验,结果显示直接灰吹法的分析结果与火试金重量法结果相吻合。 金的回收率为99.84-100.12%,RSD≤0.10%(n=6),银的回收率为99.41-100.66,RSD≤0.40%(n=6)。该方法操作简便、快捷准确,劳动强度低,有很好的适用性。 相似文献
992.
In present work, we investigated the feasibility of universal calibration models for moisture content determination of a much complicated products system of powder injections to simulate the process of building universal models for drug preparations with same INN (International Nonproprietary Name) from diverse formulations and sources. We also extended the applicability of universal model by model updating and calibration transfer. Firstly, a moisture content quantitative model for ceftriaxone sodium for injection was developed, the results show that calibration model established for products of some manufacturers is also available for the products of others. Then, we further constructed a multiplex calibration model for seven cephalosporins for injection ranging from 0.40 to 9.90%, yielding RMSECV and RMSEP of 0.283 and 0.261, respectively. However, this multiplex model could not predict samples of another cephalosporin (ceftezole sodium) and one penicillins (penicillin G procaine) for injection accurately. With regard to such limits and the extension of universal models, two solutions are proposed: model updating (MU) and calibration transfer. Overall, model updating is a robust method for the analytical problem under consideration. When timely model updating is impractical, piecewise direct standardization (PDS) algorithm is more desirable and applied to transfer calibration model between different powder injections. Both two solutions have proven to be effective to extend the applicability of original universal models for the new products emerging. 相似文献
993.
We focus on the Lp(R2) theory of the fractional Fourier transform (FRFT) for 1 ≤ p ≤ 2. In L1(R2), we mainly study the properties of the FRFT via introducing the two-parameter chirp operator. In order to get the point-wise convergence for the inverse FRFT, we introduce the fractional convolution and establish the corresponding approximate identities. Then the well-defined inverse FRFT is given via approximation by suitable means, such as fractional Gauss means and Able means. Furthermore, if the signal Fα,βf is received, we give the process of recovering the original signal f with MATLAB. In L2(R2), the general Plancherel theorem, direct sum decomposition, and the general Heisenberg inequality for the FRFT are obtained. 相似文献
994.
尚琥 《数学的实践与认识》2005,35(4):209-213
给出模糊拓扑环族直积的定义,研究它的性质,及任意模糊拓扑环族直积、与其模糊拓扑子环,与其模糊拓扑剩余环之间的同构问题.并对(QU)型模糊拓扑环关于上述问题进行研究. 相似文献
995.
997.
几类Lurie型控制系统绝对稳定性充分必要条件 总被引:3,自引:0,他引:3
本借助部分变元绝对稳定性的充要条件,得出几类Lurie型控制系统绝对稳定性充分必要条件,这些判据为显式的代数形式,易于验证,也便于在实践中应用。 相似文献
998.
999.
Jagannath Thakur 《Pramana》1991,36(5):497-510
We discuss the classical mechanics of relativistic systems with direct interaction. We show that various desiderata can all
be accommodated in the single time approach by restricting the observables to the gauge invariant variables. We show how such
observables can be constructed in general. We explicitly construct position observables in a general system and show that
they lead to separable, invariant world lines. Nonsuperluminality is explicitly demonstrated for two body systems interacting
via central forces of semibounded magnitude provided they ensure timelike canonical momenta. For two particles, our results
reproduce the usual solution in covariant equal-time gauge. 相似文献
1000.
100 ng or less amount of boron in the form of Na2B4O7 was loaded on tantalum filament of thermal ionization mass spectrometer. A serial isotope ratios of metaborate, Me=88 (Na2 11BO2) and Me=89 (Na2 11BO2) prepared with spike (10B enriched) and nature boron were determined successfully and compared with reference values. 相似文献