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981.
研究了在乙醇介质中Zn^2+对过氧化氢氧化甲基红褪色反应的负催化作用,提出了测定痕量Zn^2+的新方法,通过实验确定了最佳条件,方法简单,灵敏度高,用于水样中痕量Zn^2+的测定,结果满意。 相似文献
982.
983.
采用BPX 70毛细管色谱柱对季戊四醇的一溴代、二溴代和三溴代产物进行了分离 ,并对一溴代物、二溴代物进行了定量分析。方法快速、简便、准确度高。 相似文献
984.
Several 3‐[5‐methyl‐1‐(4‐methylphenyl)‐1,2,3‐triazol‐4‐yl]‐6‐substituted‐1,3,4‐triazolo[3,4‐b]‐1,3,4‐thiadiazoles have been synthesized and the structures of these compounds were established by elemental analysis, MS, IR and 1H NMR spectral data. 相似文献
985.
在 ICP- AES中 ,最常用来引入液体样品的方法是雾化法 .因此 ,雾化器雾化效率的高低直接影响到 ICP- AES的分析性能 [1,2 ] .目前 ,在 ICP- AES中最常用的雾化器是气动雾化器 (PN) .它的优点是简单、稳定性好 ;缺点是产生的雾滴的直径范围很宽 (一般为 1~ 50 μm) ,进样效率低 ,一般仅为 1 %~3% [3] .热雾化器是近年发展起来的一种雾化效率较高的雾化法 ,已被越来越多地用于 ICP- AES[4~ 7] .热雾化法的雾化原理与同轴气动雾化法类似 ,不同之处在于 :对于热雾化法来说 ,(1 )雾化所需的气体来自于液体样品本身而不是外加的惰性… 相似文献
986.
987.
FAN Hong-Yi HU Shan 《理论物理通讯》2006,46(1):55-57
We present a general formalism for setting up unitary transform operators from classical transforms via the technique of integration within an ordered product of operators, their normally ordered form can be obtained too. 相似文献
988.
Lattice Boltzmann simulation of fluid flows in two-dimensional channel with complex geometries 下载免费PDF全文
Boundary conditions (BCs) play an essential role in lattice
Boltzmann (LB) simulations. This paper investigates several most
commonly applied BCs by evaluating the relative L2-norm errors
of the LB simulations for two-dimensional (2-D) Poiseuille flow. It
is found that the relative L2-norm error resulting from FHML's
BC is smaller than that from other BCs as a whole. Then, based on
the FHML's BC, it formulates an LB model for simulating fluid flows
in 2-D channel with complex geometries. Afterwards, the flows
between two inclined plates, in a pulmonary blood vessel and in a
blood vessel with local expansion region, are simulated. The
numerical results are in good agreement with the analytical
predictions and clearly show that the model is effective. It is
expected that the model can be extended to simulate some real
biologic flows, such as blood flows in arteries, vessels with
stenosises, aneurysms and bifurcations, etc. 相似文献
989.
Confocal Raman microspectroscopy was used to nondestructively determine the polymorphic conversion of famotidine in the course of the milling process. A mapping system was applied to assess the blending uniformity of each polymorphic component in the milled mixture. Raman microspectroscopy combined with a thermal analyzer was also used to investigate the synergistic co‐effects of milling and heating on the polymorphic conversion of famotidine polymorphs. Famotidine has two polymorphs, forms A and B, the raw material of famotidine used was proved to be of form B. The Raman peak intensity ratio of the 2920 cm−1 band for form A and 2897 cm−1 band for form B was used to act as an indicator to evaluate the polymorphic conversion of famotidine form B to form A after different milling courses. The results indicate that the peak intensity at 2897 cm−1 gradually decreased with the milling time, whereas the peak intensity at 2920 cm−1 slowly enlarged, suggesting the polymorphic conversion of famotidine from form B to form A. The longer milling process might strongly induce and promote this polymorphic conversion of famotidine. Both polymorphic forms of famotidine were found to be well uniformly distributed within the milled samples due to their smaller varieties by using the Raman microscopic mapping system. The temperature effect could synergistically accelerate the polymorphic conversion of famotidine from form B to form A in the milled sample. The thermal‐dependent critical temperature for sharply enhancing the content of famotidine form A in each milled sample was also identified. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
990.
尿素共沉淀法制备纤维状羟基磷灰石/壳聚糖复合粉料 总被引:1,自引:0,他引:1
尿素共沉淀法制备纤维状羟基磷灰石/壳聚糖复合粉料;壳聚糖; 羟基磷酸钙; 尿素共沉淀 相似文献