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581.
Solid oxide cell electrodes need to display a wide range of combined properties, for example, electronic and ionic conductivities, catalytic activity, chemical compatibility with other parts, thermal expansion match, phase stability, and tolerance to foreign species/contaminants. It is extremely challenging for a single material to meet all these features required. Surface decoration is a remarkably adaptive strategy to provide needed features to the electrodes by introducing functioning materials through various target-guided methods. This review provides an overview of typical and novel techniques to create surface decoration on the electrodes to abruptly improve the drawbacks of the electrodes of solid oxide cells, including performance enhancement, stability of long-term operation, and tolerance to poisoning foreign species. It starts with the introduction of surface decoration experimental procedure, proceeds to crucial characterization methods that are particularly effective in identifying the properties of the surface coating, continues with target-oriented practice in terms of surface decoration materials choice and microstructure manipulation, and ends with the explorations of functioning mechanisms for the resultant behavior. With hope, the review will spark more novel utilizations of surface decoration practice to promote the technical status of the solid oxide cells for widespread commercialization in the future.  相似文献   
582.
Over the last decades, renewable and clean energy sources are being rigorously adopted along with carbon capture technologies to tackle the increasing carbon dioxide (CO2) concentration level in the environment. CO2 capture is a quintessential option for tackling global warming issues. In this context, the present paper has reviewed the process intensification equipment called a rotating packed bed (RPB), which is highly industry applicable due to high gravity (HiGee) force. This facilitates strong mass transfer characteristics, a compact design, and low energy consumption. In this review, the current research scenario of RPBs using numerical, computational fluid dynamics (CFD), and mathematical modelling, along with different machine learning approaches in the CO2 capture process, has been reviewed. The different geometry designs, hydrodynamic characteristics, performance parameters, research methods, and their effects on CO2 removal efficiency have been discussed. Furthermore, the latest experimental studies are also summarized, especially in the absorption and adsorption domain. Finally, recommendations have been given to support the RPBs in different industrial and commercial applications of CO2 removal.  相似文献   
583.
A numerical solution for the elastohydrodynamic lubrication of finite journal bearings is presented. Couple stress effects resulting from blending the lubricant with various additives are considered. Elrod's cavitation algorithm, which automatically predicts film rupture and reformation in the bearings, is implemented in the solution scheme. A simple elastic model is used to describe the elastic deformation of the bearing liner. Furthermore, the effects of surface waviness on the performance of the bearing are incorporated into the analysis. A comprehensive study illustrates the effects of couple stress, liner flexibility, and surface waviness on the steady‐state performance of finite‐width journal bearings. The results show that these effects should be considered at higher values of the eccentricity ratio.  相似文献   
584.
Silicon - Silicon is one of the most used materials in semiconductors and electronic devices. Its miniaturization in two-dimensional (2D) scale is now a great challenge to improve and/or extend its...  相似文献   
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This paper focuses on the development of multiuser access schemes for spectrum sharing systems whereby secondary users are allowed to share the spectrum with primary users under the condition that the interference observed at the primary receiver is below a predetermined threshold. In particular, two scheduling schemes are proposed for selecting a user among those that satisfy the interference constraint and achieve an acceptable signal‐to‐noise ratio level. The first scheme focuses on optimizing the average spectral efficiency by selecting the user that reports the best channel quality. In order to alleviate the relatively high feedback required by the first scheme, a second scheme based on the concept of switched diversity is proposed, where the base station (BS) scans the secondary users in a sequential manner until a user whose channel quality is above an acceptable predetermined threshold is found. We develop expressions for the statistics of the signal‐to‐interference and noise ratio as well as the average spectral efficiency, average feedback load, and the delay at the secondary BS. We then present numerical results for the effect of the number of users and the interference constraint on the optimal switching threshold and the system performance and show that our analysis results are in perfect agreement with the numerical results. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
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Neural Computing and Applications - Knowledge graphs (KGs) inherently lack reasoning ability which limits their effectiveness for tasks such as question–answering and query expansion. KG...  相似文献   
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