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Nano Research 2024年第6期17卷 5742-5752页

作者： Zhonghao Wang Wei Tang Jialin Liu Gang Zhou school of science Hubei University of TechnologyWuhan 430068China

To elucidate the synergistic effect of dual-atom catalysts(DACs)at the microscopic level,we propose and construct a prototype heteronuclear system,CuNi/TiO_(2),in which the two elements of a pair have significantly different d electron-donating abilities,as a piece in the *** density functional theory calculations,we investigate charge-dependent configurations of Cu-Ni dimers anchored on TiO_(2)by the mixing of individual constituent *** d electron-donating ability determines deposition sequence and position of transition metal atoms on oxides,establishing dimer pattern and metal-support *** interaction between Cu and Ni,beyond the coordination environment,predominately contributes to the synergistic effect.A complex adsorption-reduction behavior of H species on CuNi/TiO_(2)is *** reaction mechanism and catalytic activity of CuNi/TiO_(2)for hydrogen production are *** room temperature and high H coverages,CuNi/TiO_(2)shows better performance and efficiency than Ni1/TiO_(2).Our findings provide a new understanding of the synergistic effect on structure-activity relationships of supported dimers,which would be beneficial in the future design of various DACs or even atomically dispersed metal catalysts.

关键词： dual-atom catalysts heteronuclear/homonuclear dimers synergistic effect density functional theory hydrogen production

Effect of solidification mode on microstructure evolution and properties of magnesium alloy with long-period stacking ordered phase

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Journal of Iron and Steel Research International 2024年第5期31卷 1127-1138页

作者： Hao Li Hong-mei Chen Xu Zhang Qian-hao Zang Jing Zhang Di Feng Yan-xin Qiao Yu-hang Guo school of Materials science and Engineering Jiangsu University of Science and TechnologyZhenjiang212100JiangsuChina school of Metallurgy and Materials Engineering Jiangsu University of Science and TechnologySuzhou215600JiangsuChina

The solidification methods of electromagnetic stirring(EMS)and non-electromagnetic stirring were employed to prepare Mg–6Gd–3Y–xZn–0.6Zr(x=1,1.5,2,3)*** evolution of alloy microstructures and the changes in properties were analyzed for different Zn *** has been observed that in alloys without electromagnetic stirring,as the Zn content increases,the alloy structure gradually *** primary second phase transitions from Mg5RE phase to long-period stacking ordered(LPSO)phase,resulting in improved hardness and *** alloys subjected to electromagnetic stirring,there is a relatively higher content of the second phase,primarily consisting of LPSO *** applying electromagnetic stirring,the quantity and the type of LPSO phase in the alloy *** alloy structure becomes more uniform with electromagnetic stirring,resulting in increased hardness and reduced hardness gradients within the *** mechanical properties of alloys with electromagnetic stirring are superior to those without electromagnetic stirring.

关键词： Rare earth magnesium alloy LPSO phase Electromagnetic stirring Casting Property

Effect of annealing temperature on magnetic properties of a sintered Nd-Fe-B magnet after grain boundary diffusion with Dy_(70)Cu_(30) alloy

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Journal of Rare Earths 2024年第1期42卷 116-120,I0004页

作者： Ruipeng Qian Yuxuan Ma Fugang Chen Hui Sun Yong Zhao Yunlong Chen school of Materials science and Engineering Jiangsu University of Science and TechnologyZhenjiang212003China school of Energy and Power Engineering Jiangsu University of Science and TechnologyZhenjiang212003China

Grain boundary diffusion process(GBDP)has been developed as an effective approach to increase the coercivity of sintered Nd-Fe-B magnets by regulating the compositions and phase distributions near grain *** work aims to explore how to select the optimum annealing temperature after *** this work GBDP was performed on a sintered Nd-Fe-B magnet using Dy_(70)Cu_(30) *** GBDP the low eutectic temperature of the grain boundary phases decreases from the initial 492 to 451℃.The magnetic property dependent on different annealing temperatures near the low eutectic temperature was *** magnetic properties,especially the squareness factor of demagnetization curve show a strong dependence on the annealing *** GBDP the optimal magnetic properties can be obtained after annealing just above the low eutectic temperature of the grain boundary *** mechanism is discussed based on the microstructure analysis.

关键词： Nd-Fe-B magnet Grain boundary diffusion Annealing Dy_(70)Cu_(30)alloy Rare earths

Jigsaw-Sketch: a fast and accurate algorithm for finding top-k elephant flows in high-speed networks

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science China(Information sciences) 2024年第4期67卷 113-130页

作者： Boyu ZHANG He HUANG Yu-E SUN Yang DU Dan WANG school of Computer science and technology Soochow University school of Rail Transportation Soochow University

Finding top-k elephant flows in high-speed networks is one of the most fundamental network measurement tasks. It is more challenging than per-flow size estimation since the IDs and sizes of top-k flows must be tracked simultaneously. Most existing studies only record the IDs of a small number of elephant flows to fit their estimators in the extremely limited high-speed on-chip memory. However, these solutions need too many memory accesses when a packet arrives to track the elephant flows with high accuracy, which limits their practicability. Therefore, this paper proposes Jigsaw-Sketch, a new algorithm to find the top-k elephant flows with much fewer memory accesses while achieving high memory efficiency and accuracy. In this design, we propose a novel two-stage jigsaw storage scheme, which can capture the candidate top-k flows from massive network steams efficiently, and further find the top-k elephant flows with high memory efficiency and only a few memory accesses for each packet. Extensive experimental results based on real network traces show that Jigsaw-Sketch improves the packet processing throughput by at least 86%, while achieving smaller memory footprints and higher accuracy compared to the SOTA.

关键词： sketch top-k network measurement elephant flow high-speed networks

Long-Chain Alkenones in the South Yellow Sea Sediments and Their Indicative Significance for Haptophytes Species

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Journal of Ocean University of China 2024年第5期23卷 1287-1296页

作者： XU Yakun YANG Xinxin XIAO Rui XING Lei Key Laboratory of marine Chemistry Theory and Engineering technology Ministry of EducationOcean University of ChinaQingdao 266100China Laboratory of marine Ecology and Environment science Qingdao National Laboratory for Marine Science and TechnologyQingdao 266071China

Long-chain alkenones(LCAs)have been widely used as important biomarkers in palaeoceanographic ***,the commonly used LCAs proxies are mainly based on C_(37) alkenones,and it is still lack of the studies about the distribution and in-dications of LCAs with different chain lengths other than C_(37) ***,the composition and distribution of LCAs were ana-lyzed in surface sediments from the southern Yellow Sea(SYS)and a sedimentary core(A02-C)from the central Yellow Sea(YS)mud *** results showed that C_(37),C_(38) and C_(39) alkenones were the major LCAs in surface sediments of the SYS,and the relative contents of C_(38:2)Et,C_(37:2)Me,C_(37:3)Me,C_(38:2)Me,C_(38:3)Et,C_(38:3)Me,C_(39:2)Et and C_(39:3)Et were 18.3%-59.8%,22.6%-41.2%,7.4%-23.0%,6.6%-15.4%,3.8%-13.3%,3.6%-8.7%,2.8%-6.0% and 0.7%-3.0%,*** the relationships of U_(38Me)^(K)-U_(38Et)^(K) and U_(37)^(K')-U_(38Et)^(K) indicate that LCAs are mainly derived from Emiliania huxleyi(***).High ratios of total C_(37) alkenones to total C_(38) alkenones(K_(37)/K_(38))(1-1.2)were found in the central SYS,corresponding to the relatively high abundance of ***;while low ratios of K_(37)/K_(38)(0.7-0.9)were observed at nearshore area of the SYS where Gephyrocapsa oceanica(***)has rela-tively high *** spatial distribution of K_(37)/K_(38) ratio is also consistent with that of coccolithophores nannofossil in the *** addition,K_(37)/K_(38) ratio in core A02-C varied from 0.7 to 1.1 with a gradual decreasing trend during the past 5.5 *** suggests that the relative abundance of *** decreased gradually,caused by the changes in the Yellow Sea Warm Current(YSWC)and the East Asian Winter Monsoon(EAWM)during this period.

关键词： alkenones southern Yellow Sea sediment Yellow Sea Warm Current

Adverse effect of niobium and boron on hot deformation behavior of sulfur-containing steel

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Journal of Iron and Steel Research International 2024年第1期31卷 252-263页

作者： Guo-ning He Shi-qi Wan Bo Jiang Chao-lei Zhang Ya-zheng Liu Chun-jing Wu school of Materials science and Engineering University of Science and Technology BeijingBeijing100083China Institute for Advanced Materials and technology University of Science and Technology BeijingBeijing100083China

The hot deformation behaviors of sulfur-containing gear steel 20MnCr5 containing three different contents of Nb and B(0,0.021%Nb,and 0.024%Nb-0.0022%B)were *** compression and tenssion tests were carried out by Gleeble3800 at the austenite region from 850 to 1150℃and the adverse effects of Nb and B were analyzed by the fracture,microstructure and precipitate *** compression tests showed that the proportions of instable area in hot processing maps of 0.021%Nb and Nb-B steels were higher and the deformability of Nb free steel was *** tensile deformation experiments showed that the reduction areas of Nb free,0.021%Nb and Nb-B steels were 92%-99%,84%-98%and 67%-97%,*** addition of Nb or Nb and B inhibited the dynamic recrystallization during hot deformation,and consequently,more deformed grains were then formed in 0.021%Nb and Nb-B steels thus to obtain the microstructure with worse uniformity and then deteriorate the *** addition,the interaction between inclusions and microalloyed elements was also *** particles of 0.021%Nb and Nb-B steels dynamically precipitated during deformation and precipitated together with MnS thus to worsen the deformability,resulting in the decrease of reduction area.

关键词： Hot deformation Gear steel Processing map Dynamic recrystallization Microalloying

Nonreciprocal thermal metamaterials:Methods and applications

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International Journal of Minerals,Metallurgy and Materials 2024年第7期31卷 1678-1693页

作者： Zhengjiao Xu Chuanbao Liu Xueqian Wang Yongliang Li Yang Bai Institute for Advanced Material and technology University of Science and Technology BeijingBeijing 100083China school of Materials science and Engineering University of Science and Technology BeijingBeijing 100083China

Nonreciprocity of thermal metamaterials has significant application prospects in isolation protection,unidirectional transmission,and energy ***,due to the inherent isotropic diffusion law of heat flow,it is extremely difficult to achieve nonreciprocity of heat *** review presents the recent developments in thermal nonreciprocity and explores the fundamental theories,which underpin the design of nonreciprocal thermal metamaterials,i.e.,the Onsager reciprocity ***,three methods for achieving nonreciprocal metamaterials in the thermal field are elucidated,namely,nonlinearity,spatiotemporal modulation,and angular momentum bias,and the applications of nonreciprocal thermal metamaterials are *** also discuss nonreciprocal thermal ***,the potential applications of nonreciprocity to other Laplacian physical fields are ***,the prospects for advancing nonreciprocal thermal metamaterials are highlighted,including developments in device design and manufacturing techniques and machine learning-assisted material design.

关键词： thermal metamaterials nonreciprocity nonlinearity spatiotemporal modulation

Synergistic Coupling of Sulfide Electrolyte and Integrated 3D FeS2 Electrode Toward Long-Cycling All-Solid-State Lithium Batteries

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Energy & Environmental Materials 2024年第5期7卷 72-80页

作者： Wenyi Liu Yongzhi Zhao Chengjun Yi Weifei Hu Jiale Xia Yuanyuan Li Jinping Liu State Key Laboratory of Advanced technology for Materials Synthesis and Processing Wuhan University of Technology school of Chemistry Chemical Engineering and Life Science Wuhan University of Technology school of Integrated Circuits Huazhong University of Science and Technology

FeS2cathode is promising for all-solid-state lithium batteries due to its ultra-high capacity, low cost, and environmental friendliness. However, the poor performances, induced by limited electrode-electrolyte interface, severe volume expansion, and polysulfide shuttle, hinder the application of FeS2in all-solidstate lithium batteries. Herein, an integrated 3D FeS2electrode with full infiltration of Li6PS5Cl sulfide electrolytes is designed to address these *** a 3D integrated design not only achieves intimate and maximized interfacial contact between electrode and sulfide electrolytes, but also effectively buffers the inner volume change of FeS2and completely eliminates the polysulfide shuttle through direct solid–solid conversion of Li2S/S. Besides, the vertical 3D arrays guarantee direct electron transport channels and horizontally shortened ion diffusion paths, endowing the integrated electrode with a remarkably reduced interfacial impedance and enhanced reaction *** from these synergies, the integrated all-solid-state lithium battery exhibits the largest reversible capacity (667mAh g-1), best rate performance,and highest capacity retention of 82%over 500 cycles at 0.1 C compared to both a liquid battery and non-integrated all-solid-state lithium battery. The cycling performance is among the best reported for FeS2-based all-solid-state lithium batteries. This work presents an innovative synergistic strategy for designing long-cycling high-energy all-solid-state lithium batteries, which can be readily applied to other battery systems, such as lithium-sulfur batteries.

关键词： 3D electrolyte infiltration all-solid-state batteries FeS2 nanosheets arrays integrated 3D electrodes sulfide electrolytes

Adaptive sampling for corrugated plate digitization using a laser displacement sensor

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science China(Technological sciences) 2024年第5期67卷 1510-1523页

作者： WU ChengXing QI Qi CHEN BaiJin YANG JiXiang DING Han State Key Laboratory of Intelligent Manufacturing Equipment and technology School of Mechanical Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China State Key Laboratory of Intelligent Manufacturing Equipment and technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China

The surface quality of a corrugated plate directly determines the heat transfer property of the thermal power mechanical *** detection methods are impractical for real-world production,being slow and *** contrast,the point laser displacement sensor,employing the optical triangle method,emerges as a promising device for assessing parts with variable curvature and highly reflective *** its benefits,high-density sampling by an innate frequency introduces challenges such as data redundancy and a poor signal-to-noise ratio,potentially affecting the efficiency and precision of subsequent data *** address these challenges,adjustable frequency data sampling has been developed for this sensor,allowing adaptive sampling for corrugated plate *** process begins with surface digitization to extract discrete points,which are transformed into intersection curves using the B-spline fitting ***,dominant points are identified,considering multigeometric constraints for curvature and arch ***,the sampling signal is adjusted based on the distribution information of dominant *** results indicate that the proposed method effectively minimizes redundant sampling without compromising the accurate capture of essential geometric features.

关键词： corrugated plate laser displacement sensor adaptive sampling dominant point curvature arch height

Preparation of CIP@TiO_(2) composite with broadband electromagnetic wave absorption properties

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 197-205页

作者： Qiang Su Hanqun Wang Yunfei He Dongdong Liu Xiaoxiao Huang Bo Zhong school of Materials science and Engineering Harbin Institute of TechnologyWeihaiWeihai 264209China school of Materials science and Engineering Harbin Institute of TechnologyHarbin 150001China

Scholars aim for the improved impedance matching (Z) of materials while maintaining their excellent wave absorption properties. Based on the hydrolysis characteristics of isopropyl titanate, a simple preparation process for the coating of carbonyl iron powder(CIP) with TiO_(2) was designed. Given the TiO2coating, the Z of the CIP@TiO_(2) composite was adjusted well by decreasing the dielectric constant. Moreover, the interfacial polarization of CIP@TiO_(2) was enhanced. Ultimately, the electromagnetic-wave (EMW) absorption property of the CIP@TiO_(2)composite was improved substantially, the minimum reflection loss reached-46.07 dB, and the effective absorption bandwidth can reach 8 GHz at the composite thickness of 1.5 mm. Moreover, compared with CIP, the oxidation resistance of CIP@TiO_(2)showed remarkable improvement. The results revealed that the oxidation starting temperature of CIP@TiO_(2) as about 400℃,whereas the uncoated CIP had an oxidation starting temperature of approximately 250℃. Moreover, the largest oxidation rate temperature of CIP@TiO_(2) increased to around 550℃. This work opens up a novel strategy for the production of high-performance EMW absorbers via structural design.

关键词： carbonyl iron@titanium dioxide electromagnetic-wave absorption impedance matching oxidation resistance