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Effect of Ni content on the wear behavior of Al-Si-Cu-Mg-Ni/SiC particles composites

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International Journal of Minerals,Metallurgy and Materials 2024年第2期31卷 374-383页

作者： Yanyu liu Lina jia Wenbo Wang Zuheng jin Hu Zhang School of Materials Science and Engineering Beihang UniversityBeijing 100191China Ningbo Institute of Technology Beihang UniversityNingbo 315100China Qingdao Research Institute of Beihang University Qingdao 266000China Research Institute for Frontier Science Beihang UniversityBeijing 100191China

In recent years,the addition of Ni has been widely acknowledged to be capable of enhancing the mechanical properties of Al-Si ***,the effect of Ni on the wear behaviors of Al-Si alloys and Al matrix composites,particularly at elevated temperat-ures,remains an understudied *** this study,Al-Si-Cu-Mg-Ni/20wt%SiC particles(SiCp)composites with varying Ni contents were prepared by using a semisolid stir casting *** effect of Ni content on the dry sliding wear behavior of the prepared compos-ites was investigated through sliding tests at 25 and 350℃.Results indicated that theθ-Al_(2)Cu phase gradually diminished and eventually disappeared as the Ni content increased from 0wt%to 3wt%.This change was accompanied by the formation and increase inδ-Al_(3)CuNi andε-Al_(3)Ni phases in *** hardness and ultimate tensile strength of the as-cast composites improved,and the wear rates of the composites decreased from 5.29×10^(−4)to 1.94×10^(−4)mm^(3)/(N∙m)at 25℃and from 20.2×10^(−4)to 7×10^(−4)mm^(3)/(N∙m)at 350℃with the increase in Ni content from 0wt%to 2wt%.The enhancement in performance was due to the presence of strengthening network structures and additional Ni-containing phases in the ***,the wear rate of the 3Ni composite was approximately two times higher than that of the 2Ni composite due to the fracture and debonding of theε-Al_(3)Ni *** wear,delamination wear,and oxidation wear were the predominant wear mechanisms of the investigated composites at 25℃,whereas delamination wear and oxid-ation wear were dominant during sliding at 350℃.

关键词： Al matrix composite microstructure sliding test high temperature wear mechanism

Directional amine-based solvent extraction for simultaneous enhanced water recovery,salt separation and effective descaling from hypersaline brines

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Frontiers of Environmental Science & Engineering 2024年第3期18卷 83-92页

作者： Yuyao Zhang Litao jia jin Zhao Xuming liu Shuyu Dong Chuanyang liu Yuanyuan Cui Shougang Research Institute of Technology Beijing 100043China Research Center of Environmental Technology in Water Pollution Source Identification and Precise Supervision School of EnvironmentTsinghua UniversityBeijing 100084China

The feasibility of simultaneous water recovery,salt separation and effective descaling of hypersaline brine was investigated by diisopropylamine(DIPA)-based directional solvent extraction(DSE),using diluted/concentrated seawater with initial saline concentration range of 12–237 g/L at extraction temperatures of 5 and 15℃,*** water recovery shows an obvious boundary at saline concentration of 115 g/L under dual effect of specific water extraction efficiency and extraction *** Cl^(–) ion concentration in product water is in sharp contrast to the nearly complete removal of SO_(4)^(2–)and hardness ions,indicating that DIPA-based DSE process indeed achieved efficient separation and purification of Cl^(–) ion from hypersaline ***,the radical precipitation of Mg^(2+)and Ca^(2+)ions in form of Mg(OH)_(2)and CaCO_(3)demonstrates effective descaling potential,although it leads to more DIPA residues in dewatered raffinate than product ***,an exponential correlation between the Cl^(–) removal efficiency and specific water extraction efficiency further reveals the intrinsic relationship of water extraction process and transfer of Cl^(–) ion to the product ***,the study provides a novel approach for integrating the water recovery and separation of Cl^(–) ion from ultra-high-salinity brines with radical precipitation of Mg^(2+)and Ca^(2+) ions in one step.

关键词： Hypersaline brines Directional solvent extraction Salt separation Ca^(2+)and Mg^(2+)descaling

Toxicity of the disinfectant benzalkonium chloride(C_(14))towards cyanobacterium Microcystis results from its impact on the photosynthetic apparatus and cell metabolism

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Journal of Environmental Sciences 2024年第1期135卷 198-209页

作者： Yunlu jia Yi Huang jin Ma Shangwei Zhang jin liu Tianli Li Lirong Song Institute of Hydrobiology Chinese Academy of SciencesWuhan 430072China School of Environmental Studies China University of GeosciencesWuhan 430074China Advanced Interdisciplinary Institute of Environment and Ecology Beijing Normal UniversityZhuhai 519087China

Quaternary ammonium compounds(QACs)are commonly used in a variety of consumer and commercial products,typically as a component of *** the COVID-19 pandemic,QACs became one of the primary agents utilized to inactivate the SARS CoV-2 virus on ***,the ecotoxicological effects of QACs upon aquatic organisms have not been fully *** this study,we examined the effects of a widely used QAC(benzalkonium chloride-C_(14),BAC-14)on two toxigenic Microcystis strains and one non-toxigenic freshwater Microcystis strain and carried out an analysis focused on primary,adaptive and compensatory stress responses at apical(growth and photosynthesis)and metabolic *** analysis revealed that the two toxic Microcystis strains were more tolerant than the non-toxic strain,with 96 hr-EC_(50)values of 0.70,0.76,and 0.38 mg/L BAC-14 for toxigenic *** FACHB-905,toxigenic *** FACHB-469,and non-toxigenic *** FACHB-908,*** photosynthetic activities of the Microcystis,assessed via F_(v)/F_(m) values,were significantly suppressed under 0.4 mg/L ***,this analysis revealed that BAC-14 altered 14,12,and 8 metabolic pathways in *** FACHB-905,*** FACHB-469,and *** FACHB-908,*** is noteworthy that BAC-14 enhanced the level of extracellular microcystin production in the toxigenic Microcystis strains,although cell growth was not significantly ***,these data show that BAC-14 disrupted the physiological and metabolic status of Microcystis cells and stimulated the production and release of microcystin,which could result in damage to aquatic systems.

关键词： Disinfectants Quaternary ammonium compounds Microcystis Cyanotoxin Metabolomics Chlorophyll fluorescence

Revealing the role of electrode potential micro-environments in single Mn atoms for carbon dioxide and oxygen electrolysis

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Nano Research 2024年第9期17卷 7957-7966页

作者： Pengcheng liu anyi liu Kaili Wang Shuai Shi Mengmeng jin jingxiu liu Tao Qin Qian liu Xijun liu jia He Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion School of Chemistry and Chemical EngineeringInstitute of New-Energy Materials and Low-Carbon TechnologiesSchool of Materials Science and EngineeringTianjin University of TechnologyTianjin 300384China School of Chemistry and Chemical Engineering and Environmental Engineering Weifang UniversityWeifang 261061China Department of Electrical Engineering and Automation Luoyang Institute of Science and TechnologyLuoyang 471023China Institute for Advanced Study Chengdu UniversityChengdu 610106China State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures Guangxi Key Laboratory of Processing for Non-ferrous Metals and Featured MaterialsSchool of ResourcesEnvironment and MaterialsGuangxi UniversityNanning 530004China

Elucidation the relationship between electrode potentials and heterogeneous electrocatalytic reactions has attracted widespread *** we construct the well-defined Mn single-atom(MnSA)catalyst with four N-coordination through a simple thermal pyrolysis preparation method to investigate the electrode potential micro-environments effect on carbon dioxide reduction reactions(CO_(2)RR)and oxygen reduction reactions(ORR).MnSA catalysts generate higher CO production Faradaic efficiency of exceeding 90%at-0.9 V for CO_(2)RR and higher H_(2)O_(2)yield from 0.1 to 0.6 V with excellent ORR *** functional theory(DFT)calculations based on constant potential models were performed to study the mechanism of MnSA on CO_(2)*** thermodynamic energy barrier of CO_(2)RR is lowest at-0.9 V *** hydrogen electrode(RHE).Similar DFT calculations on the H_(2)O_(2)yield of ORR showed that the H_(2)O_(2)yield at 0.2 V was *** study provides a reasonable explanation for the role of electrode potential micro-environments.

关键词： electrode potential micro-environments Mn single-atom catalyst carbon dioxide reduction reaction oxygen reduction reaction constant potential models

Numerical investigations of the interactions between bubble induced shock waves and particle based on OpenFOAM

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Journal of Hydrodynamics 2024年第2期36卷 355-362页

作者： jia-xin Yu jin-sen Hu Yu-hang liu Yi-fan liu Dan Gao Yu-ning Zhang Key Laboratory of Power Station Energy Transfer Conversion and System Ministry of EducationSchool of Energy Power and Mechanical EngineeringNorth China Electric Power UniversityBeijing102206China

The presence of particles and the shock waves generated by the cavitation bubbles can significantly affect the safety and the performance of hydrodynamic *** the present paper,the shock waves generated by cavitation bubble collapsing near the particle are numerically investigated based on the OpenFOAM together with the numerical schlieren for the shock wave *** numerical results reveal that the stand-off distance is one of the paramount factors affecting the interactions between the particle and the shock *** different kinds of shock waves(e.g.,bubble-inception,jet formation,particle reflected and jet-split shock waves)are observed during the bubble collapsing near the *** stand-off distance smaller than 0.5 or larger than 1.1,the maximum pressure at particle surface generated by the bubble growth can surpass those of the collapse stage.

关键词： Particle-bubble interaction shockwaves jetdynamics

Constrained reinforcement learning with statewise projection: a control barrier function approach

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Science China(Information Sciences) 2024年第3期67卷 136-154页

作者： Xinze jin Kuo LI Qingshan jia Department of Automation Tsinghua University

Safety is a critical issue for reinforcement learning(RL), as it may be risky for some actual applications if the learning process involves unsafe exploration. Instead of formulating constraints as expectationbased in constrained RL, considering statewise safety in constrained RL is more meaningful. This work aims to address the issue of safe projection in RL by introducing a control barrier function that inherently learns a safe policy through a set certificate. We seek to analyze some theoretical properties of safe projection in the learning process, including convergence and performance bound, and extend the discussion into ensembles and guided controllers. Moreover, we approach analytical solutions for deterministic and stochastic system dynamics. Experimental results in different tasks show that the proposed method achieves better effects in terms of both performance and safety.

关键词： reinforcement learning safe projection control barrier function

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Investigating the Absorption and Desorption Behavior of Methylene Chloride in the Poly(aryl ether ketone) Film with Different Crystallinities

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Chinese Journal of Polymer Science 2024年第2期42卷 239-246,I0009页

作者： Hong-Ru Yang jin-Dong Zhang Dong-Ting Gao Gang liu Chun-Hai Chen jia-Nan Yao Center for Advanced Low-Dimension Materials State Key Laboratory for Modification of Chemical Fibers and Polymer MaterialsCollege of Materials Science and EngineeringDonghua UniversityShanghai201620China

Poly(aryl ether keton e)(PAEK) films with different crystallinities were obtained by controlling the cooling rate,which were subjected to the absorption and desorption of methylene chloride(CH_(2)Cl_(2)).We employed attenuated total reflection Fourier transform infrared(ATR-FTIR)spectroscopy analyses to investigate the diffusion behavior of CH_(2)Cl_(2) in PAEK films with different *** to the Fickian diffusion model,the calculated diffu sion coefficients of CH_(2)Cl_(2) in PAEK films were observed to decrease with increasing *** effect of CH_(2)Cl_(2)absorption and desorption on the mechanical properties of PAEK films with different crystallinity was further analyzed using tensile *** tensile tests exhibited that CH_(2)Cl_(2) has two concurrent effects:plasticization and solvent-induced *** scanning calorimetry(DSC) and wide-angle X-ray diffraction(WXRD) techniques further confirmed solvent-induced crystallization *** results would be beneficial to understand the solvent resistance of PAEK materials and consequently provide the practical application conditions of PAEK with a theoretical basis.

关键词： Poly(aryl ether ketone) Diffusion behavior Infrared spectra Solvent-induced crystallization Mechanical properties

SDCC: software-defined collective communication for distributed training

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Science China(Information Sciences) 2024年第9期67卷 105-125页

作者： Xin jin Zhen ZHANG Yunshan jia Yun MA Xuanzhe liu School of Computer Science Peking University Department of Computer Science and Technology Johns Hopkins University

Communication is crucial to the performance of distributed training. Today's solutions tightly couple the control and data planes and lack flexibility, generality, and performance. In this study, we present SDCC, a software-defined collective communication framework for distributed training. SDCC is based on the principle of modern systems design to effectively decouple the control plane from the data *** abstracts the operations for collective communication in distributed training with dataflow operations and unifies computing and communication with a single dataflow graph. The abstraction, together with the unification, is powerful: it enables users to easily express new and existing collective communication algorithms and optimizations, simplifies the integration with different computing engines(e.g., Py Torch and Tensor Flow) and network transports(e.g., Linux TCP and kernel bypass), and allows the system to improve performance by exploiting parallelism exposed by the dataflow graph. We further demonstrate the benefits of SDCC in four use cases.

关键词： machine learning systems distributed training deep learning collective communication software-defined networking

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Dual modification of LiNi0.83Co0.11Mn0.06O2 cathode materials by K+ doping and Li3PO4 coating for lithium ions batteries

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Rare Metals 2024年第7期43卷 3007-3018页

作者： Wei Xiao jia-Le Wang Zhi-Cheng Yi Cheng-jin liu Chang Miao Yu Xin Shu-Qing Nie College of Chemistry and Environmental Engineering Yangtze University

Li3PO4@Li0.99K0.01Ni0.83Co0.11MnO.06O2（NCM-KP） cathode powders are synthesized via K+doping in calcination processes and H3PO4coating in sol-gel processes.K+precisely enters into the lattice to widen the（003） plane to 0.4746 nm with a lower cationic disordered degree of 1.87%.Moreover,the surface residual lithium salts are treated by H3PO4to generate a uniform Li3PO4coating layer of approximately 11.41 nm,which completely covers on the surface of secondary spherical particles to improve the interfacial *** 25℃,the NCM-KP electrode delivers a discharge specific capacity of 148.9 mAh·g-1with a remarkable capacity retention ratio of 84.1% after 200 cycles at 1.0C and retains a high reversible specific capacity of 154.4 mAh·g-1at *** at 1.0C and 60℃,it can maintain a reversible discharge specific capacity of 114.6 mAh·g-1with 0.21% of capacity decay per cycle after 200 cycles,which is significantly lower than 0.40% for the pristine NCM ***,the charge transfer resistance of 238.89 Ω for the NCM-KP electrode is significantly lower than 947.41 Ω for the pristine NCM one by restricting the interfacial side ***,combining K+doping and Li3PO4coating is an effective strategy to enable the significant improvement of the electrochemical property of high-nickel cathode materials,which may be mainly attributed to the widened diffusion pathway and the formed Li3PO4protective layer,thus promoting Li+diffusion rate and preventing the erosion of HF.

关键词： High-nickel cathode material Residual lithium K + doping Li 3 PO 4 coating Lithium ions battery