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21.
Undoped and fluorine doped ZnO thin films were deposited onto glass substrates using successive ionic layer adsorption and reaction (SILAR) technique and then annealed at 350 °C in vacuum ambience. The F doping level was varied from 0 to 15 at% in steps of 5 at%. The XRD analysis showed that all the films are polycrystalline with hexagonal wurtzite structure and preferentially oriented along the (002) plane. Crystallite sizes were found to increase when 5 at% of F is doped and then decreased with further doping. It was seen from the SEM images that the doping causes remarkable changes in the surface morphology and the annealing treatment results in well-defined grains with an improvement in the grain size irrespective of doping level. All the films exhibit good transparency (>70%) after vacuum annealing. Electrical resistivity of the film was found to be minimum (1.32×10−3 Ω cm) when the fluorine doping level was 5 at%. 相似文献
22.
The simultaneous flow of gas, oil, and water forms various flow patterns due to the complex interfacial relationships. Three-phase flow patterns are classified as the gas-liquid and liquid-liquid flow patterns. Pressure drop, void fraction, liquid holdup, and phase distribution are important characteristics of the three-phase flow. These characteristics are generally associated with the three-phase flow patterns. Hence, the knowledge about flow patterns can help to predict the overall behavior of the three-phase flow. Studies have been conducted to identify three-phase flow pattern and their characteristics at various superficial velocities of gas, oil, and water. The major purpose of the studies is to gather information about the three-phase co-current flow and use it for improvement of the efficiency of the flow systems. Therefore, the accuracy of the measurement technique is critical. Several types of flow pattern identification and measurement techniques have been developed to improve accuracy and provide high-quality results. In this article, classical and advanced techniques used for the three-phase flow identification and measurement have been reviewed. The survey will help the researchers working in the area of multiphase flow to choose the right technique based on the objectives of the studies. 相似文献
23.
《Calphad》2021
The present work illustrates the effect of quasi-hydrostatic pressure on the positions and widths of the homogeneity ranges of the intermetallic phases TiFe and TiFe2 at high temperatures. The experiments were performed with Ti–Fe diffusion couples that were heat treated in a multi-anvil press at 2.5 GPa. The solubility limits of the phases were derived from the concentration profiles that were measured using electron probe microanalysis. It was found that the homogeneity ranges of TiFe and TiFe2 extend to higher titanium concentrations, if the pressure is applied. The positions of the phase boundaries of the intermetallics on the iron-rich side are not affected by the pressure. The accuracy of the experimental data including the homogeneity ranges and temperatures was verified by comparing the homogeneity ranges of β-Ti(Fe), α/δ-Fe(Ti) and γ-Fe measured in this study with the homogeneity ranges taken from literature. The pressure was calibrated using the pressure-induced phase transitions of bismuth. 相似文献
24.
为满足后续生物处理单元对固体悬浮物(SS)和铁浓度的进水要求,采用磁絮凝强化技术对厌氧消化污泥脱水液进行预处理。通过正交试验和单因素试验,本文考察了混凝水力条件、聚合氯化铝(PAC)投加量、聚丙烯酰胺(PAM)投加量、磁粉投加量及药剂投加顺序对磁絮凝效果的影响。试验结果表明:磁絮凝强化技术在快搅300r/min(2min)、慢搅100r/min(15min)、静置10min时,依次投加磁粉(40mg/L)、PAC(30mg/L)、PAM(4mg/L)时处理效果最好。在此运行条件下,SS和Fe3+去除率分别为97.61%、98.24%、絮凝指数(FI值)取得最大值、zeta电位绝对值最小,絮凝效果最佳。与对照相比,磁絮凝强化技术对SS和Fe3+去除率分别可提高3.70%和10.82%,同时絮体最大沉降速度可提高33%。磁絮凝技术处理后的出水不仅可以满足后续生物处理单元对SS和铁浓度的要求,还可以有效提高磁絮凝体的沉降速度,减小沉淀时间,具有较好的实用价值。 相似文献
25.
In line with findings on post-purchase food-choice regret, one can expect that pre-purchase anticipated regret with respect to forgone (non-chosen) alternatives has an impact on consumer food choices, especially when the choice is considered to be important. The traditional Random Utility Maximization (RUM) models for discrete choices may not fully capture this impact. This study investigates the usefulness and potential in the food domain of a discrete choice model that follows the regret minimization principle, the Random Regret Minimization (RRM) model, as an alternative and complement to existing RUM models. The two models are applied to consumer stated choices of cheese in a choice experiment. The study also investigates whether and to what extent a number of personality traits determine whether particular consumers rather choose according to utility-maximization, or regret-minimization principles. Results show that at the aggregate level the two models have a similar goodness of fit to the data and prediction ability. Still, each of them shows better fit for particular subgroups of consumers, based on personality traits. Hence, the present study reveals a potential for the RRM model applications in the food domain, and adds to the empirical literature supporting previous findings on the RRM model found in other contexts. Further research is needed to explore in which situations and for which consumer segments the RRM model is the most useful model. 相似文献
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27.
移动通信系统中功率控制研究 总被引:2,自引:0,他引:2
在阐述功率控制在移动通信系统中的发展过程的基础上,着重研究了WCDMA系统的功率控制,最后对功率控制未来的研究方向做了简要的分析。 相似文献
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30.
天然气水合物和天然气脱水新工艺探讨 总被引:3,自引:0,他引:3
探讨了天然气水合物的发展过程、形成条件以及对天然气输送管道的腐蚀堵塞作用,对我国天然气脱水创新技术———膜法脱水、汽提脱水的原理与工艺过程进行了全面论述。考察了气体处理量及操作压力等对我国1.2×105m3/d天然气膜法脱水的工业试验装置的脱水过程的影响。 相似文献