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Journal of Advanced Ceramics 2024年第5期13卷 590-601页

作者： hui Chen Yulei Zhang Yanqin Fu Wenhan Gai Junhao zhao Haohui Zhang Shaanxi Key Laboratory of Fiber Reinforced Light Composite Materials Northwestern Polytechnical UniversityXi’an 710072China Henan Key Laboratory of High Performance Carbon Fiber Reinforced Composites Institute of Carbon Matrix CompositesHenan Academy of SciencesZhengzhou 450046China

Ultra-high-temperature ceramic nanowires have shown increasing potential for use as thermal structural ***,novel single-crystal Hf_(0.5)Ta_(0.5)C solid solution nanowires were synthesized and incorporated with a HfC coating to construct a robust structure with Hf_(0.5)Ta_(0.5)C solid solution nanowires uniformly distributed and interconnected within the *** novel Hf_(0.5)Ta_(0.5)C solid solution nanowires could effectively hinder crack propagation through crack tip pinning and crack *** mechanism substantially enhanced the elastic modulus and fracture toughness of the HfC coating by 53.29%and 59.67%,*** toughened HfC coating displayed superior fracture toughness and good interfacial binding strength with the substrate to resist severe oxidation and ***,the high thermal conductivity of the toughened HfC coating promoted heat ***,in comparison to the pure HfC coating,the toughened HfC coating displayed smaller mass and linear ablation rates of−0.35 mg·s^(−1)and−0.46μm·s^(−1),which decreased by 39.66%and 36.98%,*** work not only simultaneously enhances the mechanical properties and ablation resistance of HfC-coated carbon/carbon(C/C)composites but also provides novel prospects for advanced ultrahigh-temperature ceramic nanowires under extreme conditions.

关键词： Hf_(x)Ta_(1−x)C solid solution nanowires HfC coating carbon/carbon(C/C)composites mechanical performance ablationresistance

Biomimicking synovial joints trans-scale structured AgQDs/MXene/SiOC achieving macroscale high lubrication and superior wear resistance

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Journal of Materials Science & Technology 2024年第7期174卷 63-73页

作者： Yu zhao hui Mei Peng Chang Yubo Yang Laifei Cheng Litong Zhang Science and Technology on Thermostructural Composite Materials Laboratory School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an710072China School of Textile Science and Engineering Xi’an Polytechnic UniversityXi’an710048China

Naturally optimized successful synovial joints with lightweight,high load-carrying,ultra-low friction and wear have attracted tribological communities to constantly imitate and *** impressive advances in cartilage lubrication,extending such extraordinary performance advantages to macroscale solid lubrication remains a ***,inspired by the fascinating interplay of synovial joints,a novel kind of trans-scale hierarchical structured ceramic-based composite was ***-ducing microscale Ag microspheres(AgMs)“cartilage”layer and nanoscale Ag quantum dots/MXene(AgQDs/MXene)“synovial fluid”into the interior and exterior of printed macroscale SiOC“hard bone”realistically restores the gradient structure of synovial joint *** resulted composite with ideal compressive strength(70.44 MPa)can achieve a 60.53%friction reduction and a low wear rate(2.05×10^(−6)mm 3 N^(−1)m^(−1))in dry tribo-contact for 3600 sliding cycles,while also maintaining considerable low friction(∼0.11)over 10,000 sliding cycles and long-term stable lubrication(∼0.13)for up to 50,000 re-ciprocating *** extraordinary performance can be explained by the division of macro contacts,full loading of AgMs and AgQDs/MXene,abrasive debris capture and removal,as well as the shear rolling effect induced by friction *** work opens a new avenue to develop structural lubricating mate-rials for complex engineering applications.

关键词： 3D printing Synovial joints trans-scale structure AgQDs/MXene/SiOC High lubrication Superior wear resistance

Dual-filler reinforced PVDF-HFP based polymer electrolyte enabling high-safety design of lithium metal batteries

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Nano Research 2024年第6期17卷 5251-5260页

作者： Chang Fang Kangsheng Huang Jing zhao Shiqi Tian hui Dou Xiaogang Zhang Jiangsu Key Laboratory of Electrochemical Energy Storage Technologies College of Materials Science and TechnologyNanjing University of Aeronautics and AstronauticsNanjing 210016China

Despite the high energy density of lithium metal batteries(LMBs),their application in rechargeable batteries is still hampered due to insufficient ***,we present a novel flame-retardant solid-state electrolyte based on polyvinylidene fluoride-hexafluoropropylene(PVDF-HFP)with nano SiO_(2)aerogel as an inert filler but Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)as an auxiliary component to enhance the ion *** introduction of SiO_(2)aerogels imparts the polymer electrolyte with exceptional thermal stability and flame ***,the interaction between hydroxyl groups of SiO_(2)particles and PVDF-HFP creates a strong cross-linking structure,enhancing the mechanical strength and stability of the ***,the presence of SiO_(2)aerogel and LLZTO facilitates the dissociation of lithium salts through Lewis acid-base interactions,resulting in a high ionic conductivity of 1.01×10^(−3)S·cm^(−1)and a wide electrochemical window of~5.0 V at room temperature for the prepared ***,the assembled Li|Li cell demonstrates the excellent resistance to lithium dendrite and runs stablly for over 1500 h at a current density of 0.25 mA·cm^(−2).Thus,we prepare a pouch cell with high safety,which can work normally after short-circuiting under the external folding and cutting.

关键词： polymer electrolyte SiO_(2)/Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)dual-filler non-flammable long cycle life lithium metal battery

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

Insight into the Role of Isolated Gold Atoms-Ceria Conjunction in Catalyzing the Water-Gas Shift Reaction

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Chinese Journal of Chemistry 2024年第6期42卷 636-644页

作者： Xin-Pu Fu hui-zhao Wei-Wei Wang Chun-Jiang Jia Key Laboratory for Colloid and Interface Chemistry Key Laboratory of Special Aggregated MaterialsSchool of Chemistry and Chemical EngineeringShandong UniversityJinanShandong250100 China

As the promising catalysts for the water-gas shift(WGS)reaction,the activity of Au-CeO_(2) composites is susceptible to the aggregation size and electronic state of Au *** reports were extensively focused on the discrepancy between nonmetallic Au and metallic Au nanoparticles,whereas the understanding of the authentic role of the isolated Au atoms was ***,we investigated the catalytic behavior and structural information over two types of Au/CeO_(2) catalysts,in which the predominant conjunctions were isolated Au1-CeO_(2) and Aun-CeO_(2),*** on comprehensive characterizations,particularly by in-situ Raman and in-situ DRIFTS,we found that the isolated Au atoms were responsible for enhancing the reducibility of the CeO_(2) *** CO adsorption ability on the isolated Au sites was significantly inferior to clustered Au atoms,especially at relatively high temperatures(>200°C).As a result,the boosted O vacancy on the isolated Au1-CeO_(2) conjunctions could improve the H2O activation ability for the Au-CeO_(2) catalysts and demonstrate a comparable activity to the clustered Aun-CeO_(2) *** work might deepen understanding of the catalytic function for the isolated Au1 site within Au/CeO_(2) systems while catalyzing the WGS reaction.

关键词： Isolated Au atoms Ceria-based catalysts Water-gas shift reaction Defect Adsorption

A real-time intelligent lithology identification method based on a dynamic felling strategy weighted random forest algorithm

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Petroleum Science 2024年第2期21卷 1135-1148页

作者： Tie Yan Rui Xu Shi-hui Sun zhao-Kai Hou Jin-Yu Feng School of Petroleum Engineering Northeast Petroleum UniversityDaqing163318HeilongjiangChina Sanya Offshore Oil&Gas Research Institute Northeast Petroleum UniversitySanya572025HainanChina

Real-time intelligent lithology identification while drilling is vital to realizing downhole closed-loop drilling. The complex and changeable geological environment in the drilling makes lithology identification face many challenges. This paper studies the problems of difficult feature information extraction,low precision of thin-layer identification and limited applicability of the model in intelligent lithologic identification. The author tries to improve the comprehensive performance of the lithology identification model from three aspects: data feature extraction, class balance, and model design. A new real-time intelligent lithology identification model of dynamic felling strategy weighted random forest algorithm(DFW-RF) is proposed. According to the feature selection results, gamma ray and 2 MHz phase resistivity are the logging while drilling(LWD) parameters that significantly influence lithology identification. The comprehensive performance of the DFW-RF lithology identification model has been verified in the application of 3 wells in different areas. By comparing the prediction results of five typical lithology identification algorithms, the DFW-RF model has a higher lithology identification accuracy rate and F1 score. This model improves the identification accuracy of thin-layer lithology and is effective and feasible in different geological environments. The DFW-RF model plays a truly efficient role in the realtime intelligent identification of lithologic information in closed-loop drilling and has greater applicability, which is worthy of being widely used in logging interpretation.

关键词： Intelligent drilling Closed-loop drilling Lithology identification Random forest algorithm Feature extraction

Characteristics and distribution of microstructures in high pressure die cast alloys with X-ray microtomography:A review

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China Foundry 2024年第5期21卷 427-444页

作者： Hai-dong zhao Xue-ling Wang Qian Wan Wen-hui Bai Fei Liu School of Mechanical and Automotive Engineering South China University of TechnologyGuangzhou 510640China

Al and Mg alloy high pressure die castings(HPDC)are increasingly used in automotive *** microstructures in the castings have decisive effect on the casting mechanical properties,in which the microstructure characteristics are fundamental for the investigation of the microstructure-property *** the past decade,the microstructure characteristics of HPDC Al and Mg alloys,especially micro-pores andα-Fe,have been investigated from two-dimensional(2D)to threedimensional with X-ray micro-computed tomography(μ-CT).This paper provides an overview of the current understanding regarding the 3D characteristics and formation mechanisms of microstructures in HPDC alloys,their spatial distributions,and the impact on mechanical ***,it outlines future research directions for the formation and control of heterogeneous microstructures in HPDC alloys.

关键词： high pressure die casting microstructure three-dimensional characteristics distribution Al and Mg alloys

Tuning interface mechanism of FeCo alloy embedded N,S-codoped carbon substrate for rechargeable Zn-air battery

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Journal of Energy Chemistry 2024年第6期93卷 400-410,I0010页

作者： hui Chang Lulu zhao Shan zhao Zong-Lin Liu Peng-Fei Wang Ying Xie Ting-Feng Yi School of Materials Science and Engineering Northeastern UniversityShenyang 110819LiaoningChina Key Laboratory of Functional Inorganic Material Chemistry Ministry of EducationSchool of Chemistry and Materials ScienceHeilongjiang UniversityHarbin 150080HeilongjiangChina Key Laboratory of Dielectric and Electrolyte Functional Material Hebei Province School of Resources and MaterialsNortheastern University at QinhuangdaoQinhuangdao 066004HebeiChina

The interface mechanism between catalyst and carbon substrate has been the focus of *** this paper,the FeCo alloy embedded N,S co-doped carbon substrate bifunctional catalyst(FeCo/S-NC)is obtained by a simple one-step pyrolysis *** experimental results and density functional theory(DFT)calculation show that the formation of FeCo alloy is conducive to promoting electron transfer,and the introduction of S atom can enhance the interaction between FeCo alloy and carbon substrate,thus inhibiting the migration and agglomeration of particles on the surface of carbon *** FeCo/SNC catalysts show outstanding performance for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).FeCo/S-NC shows a high half-wave potential(E_(1/2)=0.8823 V)for ORR and a low overpotential at 10 mA cm^(-2)(E_(j=10)=299 mV)for *** addition,compared with Pt/C+RuO_(2) assembled Zn-air battery(ZAB),the FeCo/S-NC assembled ZAB exhibits a larger power density(198.8 mW cm^(-2)),a higher specific capacity(786.1 mA h g_(zn)~(-1)),and ultra-stable cycle *** results confirm that the optimized composition and the interfacial interaction between catalyst and carbon substrate synergistically enhance the electrochemical performance.

关键词： FeCo alloy N S co-doped carbon DFT calculation Zn-air batteries Interfacial interaction

Integrating theory with the nanoreactor concept to synthesize hollow carbon sphere-encapsulated PtNi alloys for enhanced H_(2) generation

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Carbon Energy 2024年第7期6卷 150-162页

作者： Yufeng Wu Minwei Song Ziyi zhao Guang-hui Wang Changlong Wang Didier Astruc Institute of Circular Economy Faculty of Materials and ManufacturingBeijing University of TechnologyBeijingChina Key Laboratory of Biofuels Qingdao Institute of Bioenergy and Bioprocess TechnologyChinese Academy of SciencesQingdaoChina ISM UMR CNRS N°5255Universitéde BordeauxTalence CedexFrance

The rational design of efficient bimetallic nanoparticle(NP)catalysts is challenging due to the lack of theoretical understanding of active components and insights into the mechanisms of a specific ***,we report the rational design of nanoreactors comprising hollow carbon sphere-confined PtNi bimetallic NPs(PtNi@HCS)as highly efficient catalysts for hydrogen generation via ammonia borane hydrolysis in *** both density functional theory calculations and molecular dynamics simulations,the effects of an active PtNi combination and the critical synergistic role of a hollow carbon shell on the molecule diffusion adsorption behaviors are *** isotope effects and theoretical calculations allow the clarification of the mechanism,with oxidative addition of an O-H bond of water to the catalyst surface being the rate-determining *** remarkable catalytic activity of the PtNi@HCS nanoreactor was also utilized for successful tandem catalytic hydrogenation reactions,using in situ-generated H_(2) from ammonia borane with high *** concerted design,theoretical calculations,and experimental work presented here shed light on the rational elaboration of efficient nanocatalysts and contribute to the establishment of a circular carbon economy using green hydrogen.

关键词： ammonia borane hydrogen nanoalloy nanoreactor solid catalyst

A Comparative Study of the Power-law Relationship between the Pulse width and Energy of Precursor and Main Burst

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Research in Astronomy and Astrophysics 2024年第3期24卷 144-168页

作者： hui-Ying Deng zhao-Yang Peng Jia-Ming Chen Dan Zhu College of Physics and Electronic Information Yunnan Normal UniversityKunming 650500China

In gamma-ray burst prompt emission,there is still no consistent conclusion if the precursor and main burst share the same *** this paper,we try to study this issue based on the relationship between pulse width and energy of the precursor and main *** systematically search the light curve data observed by Swift/BAT and Fermi/GBM,and find 13 long bursts with well-structured precursors and main *** fitting the precursor light curve of each different energy channel with the Norris function,we find that there is not only a power-law relationship between precursor width and energy,but also a power-law relationship between the ratio of the rising width to the decaying width and *** comparing the relationship between the precursors and the main burst pulses,we find that the distribution of the precursors and the relationship between the power-law indices are roughly the same as those of the main *** addition,it is found that the precursor width distribution as well as the upper limit of the pulse width ratio does not exceed 1 and both are asymmetric,which are also consistent with the main *** indicate that the precursor and the main burst are indistinguishable,and the precursor and the main burst may have the same physical origin.

关键词： methods data analysis-(stars) gamma-ray burst general-shock waves