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51.
Summary Carbon deposits on the surface ofRu/Fe2O3 catalysts used in the water-gas shift reaction have been investigated by Auger Electron Spectrometry. A correlation has been
found between the thickness of the carbon deposit and the catalytic activity in WGSR. The carbon deposit covers the metallic
active centers and blocks their contact with reagents. The dotting of the iron oxide support with sodium has been found to
reduce the amount of carbon deposit. . 相似文献
52.
超临界流体色谱流程设计及其应用 总被引:1,自引:1,他引:0
本文设计了多功能超临界流体色谱流程,流程中包括毛细管/微填充柱SFC,GC,计算机控制温度、压力、密度及信号采集、处理,配置有超临界流体萃取池,解决了超临界流体色谱分流口易堵问题。利用该流程,将石腊、DC-200气相色谱固定相、黄油、蜂蜡、救心油、红花油等样品进行超临界流体色谱分离。 相似文献
53.
54.
Reynaldo C. Castells Eleuterio L. Arancibia Angel M. Nardillo 《Journal of solution chemistry》1993,22(1):85-94
The retention behavior of eight halomethanes and four saturated hydrocarbons was measured in gas chromatographic stationary phases consisting in tri-n-octylamine (TOA), squalane (SQ) and six TOA+SQ mixtures, at 55.0, 58.5, 62.5 and 65.0°C. Equlibrium constants for complex formation were extracted from experimental data by using a lattice model developed by Martire. The results may be interpreted in terms of the formation of weak hydrogen-bonded complexes, with sociation constants of about 0.13 L-mol–1 for haloforms and 0.07 L-mol–1 for dihalomethanes at 60°C. 相似文献
55.
Summary A system for capillary electrophoresis combined with enzymatic assay has been evaluated for the two enzymes glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase. Instrumentation included a post-column reactor coupled to the separation capillary by a liquid junction. A technique for generating a substrate solution flow into the reactor by utilizing two high voltage supplies is proposed. This method offers a high degree of freedom in optimizing the separation and enzymatic reaction conditions individually. Possibilities for improving the enzymatic assay sensitivity were also examined. 相似文献
56.
M. Hanson 《Chromatographia》1994,39(7-8):431-437
Summary Pressure/temperature variation in SFC was shown to influence selectivity towards steroids. Major changes were observed for polar column packings compared to non-polar packings and variation of the amount of modifier showed that this is valid over the whole investigated range. The effect is underlined by a fall in resolution in the low density range (low pressure/high temperature) for polar stationary phases and appears to be significantly larger than for non-polar phases. Major selectivity shifts induced by variation of the physical properties of the mobile phase are considered to be due to the greater effect of polar modifiers on the nature of polar stationary phases than on non-polar phases. 相似文献
57.
Summary Experiments and simulations prove that correlation chromatography can greatly reduce the disadvantage of a non-linear response of the chromatographic column. A factor that has been accepted as being an important source of error in correlation or multiplex chromatography, has been shown not to be. Separations affected, improve dramatically when correlation chromatography is used, and a substantial amount of correlation noise only arises when there is a large difference in separation between a conventional chromatogram and a correlogram.A model has been developed for simulating these nonlinearities. It is shown that, especially for correlation chromatography, the simulation results match the practical measurements very well. 相似文献
58.
Separation of 23 dansylated amino acids by micellar electrokinetic chromatography at low temperature
Summary The baseline separation of 23 dansylated amino acids (including 3 didansylated species) is reported. Lowering of the analysis
temperature and fine control of the surfactant concentration were essential in obtaining this result. Calibration graphs with
good linearity were obtained. 相似文献
59.
Phase Relations and Sodium Ion Conductivity within the Quasi-binary System Na2SiF6/Na2AIF6 . The phase diagram of the Na2SiF6/Na3AlF6 system has been determined by means of x-ray powder diffraction, thermal analysis and conductivity measurements in the sub-solidus region. Na3AlF6 accomodates up to 73 mol.-% Na2SiF6 maintaining the crystal structure type. The sodium ion conductivity increases by about five orders of magnitude upon doping Na3AlF6 with Na2SiF6. 相似文献
60.
In circuit-switched networks call streams are characterized by their mean and peakedness (two-moment method). The GI/M/C/0 system is used to model a single link, where the GI-stream is determined by fitting moments appropriately. For the moments of the overflow traffic of a GI/M/C/0 system there are efficient numerical algorithms available. However, for the moments of the freed carried traffic, defined as the moments of a virtual link of infinite capacity to which the process of calls accepted by the link (carried arrival process) is virtually directed and where the virtual calls get fresh exponential i.i.d. holding times, only complex numerical algorithms are available. This is the reason why the concept of the freed carried traffic is not used. The main result of this paper is a numerically stable and efficient algorithm for computing the moments of freed carried traffic, in particular an explicit formula for its peakedness. This result offers a unified handling of both overflow and carried traffics in networks. Furthermore, some refined characteristics for the overflow and freed carried streams are derived. 相似文献