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local concentration of middle and heavy rare earth elements in the col on the weathered crust elution-deposited rare earth ores

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Journal of Rare Earths 2018年第5期36卷 552-558页

作者： Zhenyue Zhang Ningjie Sun Zhengyan He Ru'an Chi School of Minerals Processing and Bioengineering Central South University Key Laboratory for Green Chemical Process of Ministry of Education Wuhan Institute of Technology

This present study focused on investigating the content and relative enrichment multiple of rare earth elements（REEs） in different terrain of weathered ore body, and the value of light rare earth elements/middle and heavy rare earth elements（LREEs/HREEs）, in order to understand the mobilization and redistribution of HREEs, Furthermore, the abrasion pH was investigated as well, The results show that the average contents of HREEs in the knap, ridge and col are 37.26, 61.71, and 271.3 μg/g, respectively. The value of LREEs/HREEs is decreased from 16.78 to 7.914 between knap and col and the relative enrichment multiple of HREEs is as follows： CCol-HREEs 〉 CRidge-HREEs 〉 0. It is indicated the HREEs is concentrated in the col and the enrichment degree of HREEs is stronger than the ridge and the knap. Rare earth elements fractionation is exhibited in the different terrain of weathered ore body. Based on this study, the finding that HREEs concentrate in the lower terrain of weathered crust elution-deposited rare earth ores, such as in the col, would become a marker or indicator to search for middle and heavy rare earth enriched zone.

关键词： Weathered crust elution-deposited rareearth ores Topography conditions Middle and heavy rare earth elements local concentration

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An immune local concentration based virus detection approach

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Journal of Zhejiang University-Science C(Computers and Electronics) 2011年第6期12卷 443-454页

作者： Wei WANG MOE Key Laboratory of Machine Perception Peking University Beijing 100871 China Department of Machine Intelligence School of Electronics Engineering and Computer Science Peking University Beijing 100871 China

Along with the evolution of computer viruses, the number of file samples that need to be analyzed has constantly increased. An automatic and robust tool is needed to classify the file samples quickly and efficiently. Inspired by the human immune system, we developed a local concentration based virus detection method, which connects a certain number of two-element local concentration vectors as a feature vector. In contrast to the existing data mining techniques, the new method does not remember exact file content for virus detection, but uses a non-signature paradigm, such that it can detect some previously unknown viruses and overcome the techniques like obfuscation to bypass signatures. This model first extracts the viral tendency of each fragment and identifies a set of statical structural detectors, and then uses an information-theoretic preprocessing to remove redundancy in the detectors’ set to generate ‘self’ and ‘nonself’ detector libraries. Finally, ‘self’ and ‘nonself’ local concentrations are constructed by using the libraries, to form a vector with an array of two elements of local concentrations for detecting viruses efficiently. Several standard data mining classifiers, including K -nearest neighbor (KNN), radial basis function (RBF) neural networks, and support vector machine (SVM), are leveraged to classify the local concentration vector as the feature of a benign or malicious program and to verify the effectiveness and robustness of this approach. Experimental results show that the proposed approach not only has a much faster speed, but also gives around 98% of accuracy.

关键词： local concentration Artificial immune system Virus detection

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Self-supported copper-based gas diffusion electrodes improve the local CO_(2)concentration for efficient electrochemical CO_(2)reduction

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Frontiers of Chemical Science and Engineering 2024年第3期18卷 51-62页

作者： Azeem Mustafa Bachirou Guene Lougou Yong Shuai Zhijiang Wang Haseeb-ur-Rehman Samia Razzaq Wei Wang Ruming Pan Jiupeng Zhao Key Laboratory of Aerospace Thermophysics of MIIT Harbin Institute of TechnologyHarbin150001China School of Energy Science and Engineering Harbin Institute of TechnologyHarbin150001China MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage School of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin150001China Mechanical Engineering Department University of Engineering and TechnologyTaxila47050Pakistan School of Aerospace Mechanical and Mechatronics EngineeringUniversity of SydneySydney2006Australia

Electrochemical CO_(2)reduction is a sustainable approach in green chemistry that enables the production of valuable chemicals and fuels while mitigating the environmental impact associated with CO_(2)*** its several advantages,this technology suffers from an intrinsically low CO_(2)solubility in aqueous solutions,resulting in a lower local CO_(2)concentration near the electrode,which yields lower current densities and restricts product *** diffusion electrodes(GDEs),particularly those with tubular architectures,can solve these issues by increasing the local CO_(2)concentration and triple-phase interface,providing abundant electroactive sites to achieve superior reaction *** this study,robust and self-supported Cu flow-through gas diffusion electrodes(FTGDEs)were synthesized for efficient formate production via electrochemical CO_(2)*** were further compared with traditional Cu electrodes,and it was found that higher local CO_(2)concentration due to improved mass transfer,the abundant surface area available for the generation of the triple-phase interface,and the porous structure of Cu FTGDEs enabled high formate Faradaic efficiency(76%)and current density(265 mA¸cm^(−2))at–0.9 V *** hydrogen electrode(RHE)in 0.5 mol·L^(−1)*** combined phase inversion and calcination process of the Cu FTGDEs helped maintain a stable operation for several *** catalytic performance of the Cu FTGDEs was further investigated in a non-gas diffusion configuration to demonstrate the impact of local gas concentration on the activity and performance of electrochemical CO_(2)*** study demonstrates the potential of flow-through gas-diffusion electrodes to enhance reaction kinetics for the highly efficient and selective reduction of CO_(2),offering promising applications in sustainable electrochemical processes.

关键词： CO_(2)electroreduction flow-through delivery hollow fiber structure local concentration formate

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