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991.
多孔介质中聚合物溶液衰竭层效应的计算 总被引:1,自引:1,他引:0
通过实验测定了聚合物溶液在流变仪中的流变曲线和流过多孔介质的流变曲线,用双流体模型和线形衰竭层模型计算了衰竭层效应.通过改变聚合物溶液浓度和岩心渗透率,计算了较宽浓度范围和渗透率范围内的衰竭层效应.结果表明:衰竭层厚度大小与聚合物分子的回旋半径级别相当;线形模型计算的衰竭层厚度高于双流体模型计算的结果.在聚合物浓度较低时,衰竭层厚度变化不大;浓度高于缠结浓度时,衰竭层厚度随浓度升高而降低.但是,即使浓度高至1500mg/L,衰竭层厚度对表观粘度的影响仍很大;衰竭层厚度与多孔介质的渗透率大小无关.因此,这种效应有利于聚合物在非均质油藏低渗透部位的流动,能起到扩大聚合物驱波及体积的作用. 相似文献
992.
针对北京燕山分公司炼油厂0.6Mt/a连续重整装置实际生产中,副产氢气中碳氧化合物含量不合格原因,进行初步分析探讨,并提出建议。 相似文献
993.
A method is presented to assess oxygen uptake rates which operates at constant dissolved oxygen concentration (DO). This method involves DO-stat titrations by controlled addition of a diluted H2O2 solution to a batch volume of activated sludge. The titrant flow rate is proportional to the biomass respiration rate, while the mass of H2O2 added is proportional to the oxidized organics. Classical batch respirometries (with and without gas flow, i.e., “open” and “closed”) were compared to the DO-stat technique using first NaSO2 as reducing chemical and then respiring aerobic biomass. An excellent correlation was found among estimates of oxygen consumption rate and short term yield coefficient by the three techniques. Inhibition by H2O2 was found to be negligible for biomass concentration as volatile suspended solids of ≥ 1.5–2 g?/L. 相似文献
994.
T. D. Patel T. R. Bott 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1991,52(2):187-199
Using a specially designed miniature probe mounted into a plate across which water contaminated with the bacterium Pseudomonas fluorescens was flowing, oxygen levels at the biofilm/substrate interface have been determined. The experimental results show a rapid fall in the amount of oxygen available to the micro-organisms in the layers near the interface. As the biofilm approached 300 μm in thickness higher flow velocities across the biofilm had little effect on oxygen availability in the regions near the interface. 相似文献
995.
智能型溶解氧分析仪的研制 总被引:3,自引:0,他引:3
介绍了溶解氧分析仪的硬件结构和软件设计。该仪器由极谱型复膜氧电极传感器和AT89C52单片微机系统两大部分组成,软件采用模块式编制,结构紧凑,操作简便。仪器的测量范围为:溶解氧:0~19.99mg/L(温度为-10℃~40℃);测量精度:溶解氧±0.3mg/L(温度±1℃ 相似文献
996.
997.
998.
M.A. Del Nobile G.G. Buonocore E. La Notte L. Nicolais 《Journal of food science》2003,68(6):2017-2021
ABSTRACT: We present a mathematical model to predict the oxygen-permeability coefficient of nylon film as a function of the water activity at the upstream and downstream side of the film. To validate the model, oxygen-permeability tests were conducted at 25 °C. The fitting and predictive ability of the proposed model was successfully tested by fitting and predicting the oxygen-permeability coefficient. The obtained results point out the need for a more accurate analysis of the oxygen and water-transport phenomena in the case of water-sensitive packaging films like nylon. 相似文献
999.
Oxygen has always been considered to be a major contaminant in the organo-metallic vapor phase epitaxy (OMVPE) of Al
x
Ga1−x
As. Oxygen incorporation has been invoked as a contributor to low luminescence efficiency, dopant compensation and degradation
of surface morphology among other deleterious effects. This study presents quantitative measurements of oxygen concentration
in nominally high purity Al
x
Ga1−x
As. The oxygen concentration was measured as a function of alloy composition, growth temperature, andV/III ratio. Quantitative secondary ion mass spectroscopy (SIMS) measurements were used to determine the oxygen content as well
as the carbon concentration in the film. The oxygen concentration increases with decreased growth temperature and V/III ratio
while increasing superlinearly with Al content in the epitaxial layer. 相似文献
1000.
XPS Studies on Rare Earth Oxide LSCO/YSZ Electrodes 总被引:6,自引:0,他引:6
The X-ray diffraction spectra and X-my photoelectron spectroscopy were measured for Sr-doped Lal-xSrx CoO3 materials with perovskite structure prepared by the solid-state reaction method. The influence of heat-treatment tempera-ture on the average crystal size of Lal-xSrx CoO3 was studied. The surface chemical states of Lal-xSrxCoO3 cathodes with different Sr-doped content were discussed. The experimental results show that average crystal size of Lal-xSrxCoO3 under the condition of heat-treatment in the range of 900- 1200℃ is larger than that at other temperatures, which is of benefit to forming porous electrodes. When La is replaced by Sr gradually, the oxygen vacancy concentration increases. It is of benefit to enhancing the transport property of oxygen ion. 相似文献