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Effects of the extrusion parameters on microstructure,texture and room temperature mechanical properties of extruded Mg-2.49Nd-1.82Gd-0.2Zn-0.2Zr alloy

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International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 136-146页

作者： Chenjin Zhang Guangyu Yang Lei Xiao Zhiyong kan Jing Guo Qiang li Wanqi Jie State key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China College of Materials Science and Engineering Fuzhou UniversityFuzhou 350108China College of Chemistry and Environmental Science Qujing Normal UniversityQujing 655011China

Microstructure,texture,and mechanical properties of the extruded Mg-2.49Nd-1.82Gd-0.2Zn-0.2Zr alloy were investigated at different extrusion temperatures(260 and 320℃),extrusion ratios(10:1,15:1,and 30:1),and extrusion speeds(3 and 6 mm/s).The experimental results exhibited that the grain sizes after extrusion were much finer than that of the homogenized alloy,and the second phase showed streamline distribution along the extrusion direction(ED).With extrusion temperature increased from 260 to 320℃,the microstructure,texture,and mechanical properties of alloys changed *** dynamic recrystallization(DRX)degree and grain sizes enhanced as the extrusion ratio increased from 10:1 to 30:1,and the strength gradually decreased but elongation(EL)*** the extrusion speed increased from 3 to 6 mm/s,the grain sizes and DRX degree increased significantly,and the samples presented the typical-rare-earth(RE)*** alloy extruded at 260℃ with extrusion ratio of 10:1 and extrusion speed of 3 mm/s showed the tensile yield strength(TYS)of 213 MPa and EL of 30.6%.After quantitatively analyzing the contribution of strengthening mechanisms,it was found that the grain boundary strengthening and dislocation strengthening played major roles among strengthening *** results provide some guidelines for enlarging the industrial application of extruded Mg-RE alloy.

关键词： Mg-rare earth alloys extrusion temperature extrusion ratio extrusion speed strengthening mechanisms

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Preparation of silver nanoparticles through the reduction of straw-extracted lignin and its antibacterial hydrogel

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 504-514页

作者： Lou Zhang Shuo li Fu Tang Jingkai Zhang Yuetong kang Hean Zhang lidong li State key Laboratory for Advanced Metals and Materials School of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing 100083China

Silver nanoparticles(Ag NPs)have attracted attention in the field of biomaterials due to their excellent antibacterial ***,the reducing and stabilizing agents used for the chemical reduction of Ag NPs are usually toxic and may cause water *** this work,Ag NPs(31.2 nm in diameter)were prepared using the extract of straw,an agricultural waste,as the reducing and stabilizing *** analysis revealed that the straw extract contained lignin,the structure of which possesses phenolic hydroxyl and methoxy groups that facilitate the reduction of silver salts into Ag *** surfaces of Ag NPs were negatively charged due to the encapsulation of a thin layer of lignin molecules that prevented their *** the prepared Ag NPs were added to the precursor solution of acrylamide,free radical polymerization was triggered without the need for extra heating or light irradiation,resulting in the rapid formation of an Ag NP-polyacrylamide composite *** inhibition zone test proved that the composite hydrogel possessed excellent antibacterial ability due to the presence of Ag *** prepared hydrogel may have potential applications in the fabrication of biomedical materials,such as antibacterial dressings.

关键词： silver nanoparticles hydrogel straw extraction antibacterial

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Synergistic effect of bonding heterogeneity and phonon localization in introducing excellent thermoelectric properties in layered heteroanionic NdZnSbO material

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Journal of Energy Chemistry 2025年第1期100卷 259-272页

作者： Da Wan Shuwei Tang Shulin Bai Xiaodong li Peng Ai Wanrong Guo Tuo Zheng College of Materials Science and Engineering Liaoning Technical University Faculty of Chemistry Northeast Normal University

Layered rare-earth metal oxides, harnessing the dual properties of oxides and two-dimensional layered materials, exhibit remarkable thermal stability and quantum confinement effects. Therefore, this work adopts the first-principles calculation combined with the Boltzmann transport theory to predict the thermoelectric properties of NdZnSbO compound. The coexistence of weak interlayer van der Waals interactions, robust intralayer ionic bonding, and partial covalent bonding leads to remarkable bonding heterogeneity, which engenders pronounced phonon scattering and imposes constraints on thermal transport along the out-of-plane direction. The weakened chemical bonds induced by the antibonding states, together with the rattling-like behavior of the Zn atom, culminate in the profound anharmonicity in the layered NdZnSbO compound. The weakening bond and heavy element contribute to the softness of phonon modes, which significantly diminishes the phonon group velocity. The redistribution-dominated four-phonon scattering process spans a large optical gap, which effectively reduces the lattice thermal conductivity. The NdZnSbO compound exhibits direct semiconductor characteristic with a bandgap of 0.73 e V by adopting the Heyd-Scuseria-Ernzerhof(HSE06) functional in combination with spin–orbit coupling(SOC) effect. The multi-valley feature of NdZnSbO compound augur favorably for band degeneracy, thus amplifying the power factor. Consequently, an optimal figure-of-merit(ZT) of 3.40 at 900 k is achieved for the n-type NdZnSbO compound. The present study delves deeply insights into the origins for the low thermal conductivity of NdZnSbO compound and proposes an optimization scheme to enhance overall thermoelectric performance.

关键词： Bond strength (chemical)

Mechanical Properties of Railway High-strength Manufactured Sand Concrete: Typical lithology, Stone Powder Content and Strength Grade

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Journal of Wuhan University of Technology(Materials Science) 2025年第1期40卷 194-203页

作者： WANG Zhen li Huajian HUANG Fali YANG Zhiqiang WEN Jiaxin SHI Henan Railway Engineering Research Institute China Academy of Railway Science Corporation LimitedBeijing 100081China State key Laboratory for Track Technology of High-Speed Railway Beijing 100081China

In order to achieve the large-scale application of manufactured sand in railway high-strength concrete structure,a series of high-strength manufactured sand concrete(HMC)are prepared by taking the manufactured sand lithology(tuff,limestone,basalt,granite),stone powder content(0,5%,10%,15%)and concrete strength grade(C60,C80,C100)as *** evolution of mechanical properties of HMC and the correlation between cubic compressive strength and other mechanical properties are *** to river sand,manufactured sand enhances the cubic compressive strength,axial compressive strength and elastic modulus of concrete,while its potential microcracks weaken the flexural strength and splitting tensile strength of *** powder content displays both positive and negative effects on mechanical properties of HMC,and the stone powder content is suggested to be less than 10%.The empirical formulas between cubic compressive strength and other mechanical properties are proposed.

关键词： manufactured sand concrete railway mechanical property lithology stone powder content

Broadband low-frequency sound absorption of multifunctional composite metastructure

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Science China Technological Sciences 2025年

作者： Yilong YANG Shanshan liU Yan li Tong GAO Yongdong PAN Yong li Yabin JIN School of Aerospace Engineering and Applied Mechanics Tongji University Institute of Acoustics School of Physics Science and Engineering Tongji University Shanghai Institute of Aircraft Mechanics and Control State International Joint Research Center of Aerospace Design and Additive Manufacturing Northwestern Polytechnical University Shanghai key Laboratory of Intelligent Sensing and Detection Technology School of Mechanical and Power Engineering East China University of Science and Technology

In this study, we fabricated multifunctional metastructures from carbon fiber-reinforced plastic composites using additive manufacturing technology. These metastructures are characterized by their lightweight, load-bearing capacity, and broadband low-frequency sound absorption properties. The metastructure consists of 36 unit cells, and non-local coupling mechanism was considered for designing the sound absorption performance. We developed an acoustic impedance theory tailored for the metastructure, facilitating an analysis of thermal and viscous dissipation mechanisms. It is proven theoretically and experimentally that the proposed composite metastructure can achieve a noise reduction with an average sound absorption coefficient greater than 0.9 across frequencies in the rage of 330–1500 Hz. We also studied the metastructure’s quasi-static and cyclic compression performance, confirming its efficient absorption capabilities after cyclic compression. The proposed design and additive manufacturing method for composite metastructures provides a novel pathway for creating lightweight, multifunctional structures with diverse applications, such as aerospace engineering.

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Recent Strategies and Advances in Hydrogel‑Based Delivery Platforms for Bone Regeneration

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Nano-Micro Letters 2025年第3期17卷 389-439页

作者： Xiao Wang Jia Zeng Donglin Gan kun ling Mingfang He Jianshu li Yongping Lu Scientific and Technological Innovation Center for Biomedical Materials and Clinical Research Guangyuan Key Laboratory of Multifunctional Medical HydrogelGuangyuan Central HospitalGuangyuan 628000People’s Republic of China Jiangsu Collaborative Innovation Center of Biomedical Functional Materials Jiangsu Key Laboratory of Bio‑Functional MaterialsSchool of Chemistry and Materials ScienceNanjing Normal UniversityNanjing 210023People’s Republic of China College of Polymer Science and Engineering State Key Laboratory of Polymer Materials EngineeringSichuan UniversityChengdu 610065People’s Republic of China

Bioactive molecules have shown great promise for effectively regulating various bone formation processes,rendering them attractive therapeutics for bone ***,the widespread application of bioactive molecules is limited by their low accumulation and short half-lives in *** have emerged as ideal carriers to address these challenges,offering the potential to prolong retention times at lesion sites,extend half-lives in vivo and mitigate side effects,avoid burst release,and promote adsorption under physiological *** review systematically summarizes the recent advances in the development of bioactive molecule-loaded hydrogels for bone regeneration,encompassing applications in cranial defect repair,femoral defect repair,periodontal bone regeneration,and bone regeneration with underlying ***,this review discusses the current strategies aimed at improving the release profiles of bioactive molecules through stimuli-responsive delivery,carrier-assisted delivery,and sequential ***,this review elucidates the existing challenges and future directions of hydrogel encapsulated bioactive molecules in the field of bone regeneration.

关键词： Hydrogel Bone regeneration Bioactive molecules Drug delivery Nano-/microscale carriers

MixerkT:A knowledge Tracing Model Based on Pure MLP Architecture

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Computers, Materials & Continua 2025年第1期82卷 485-498页

作者： Jun Wang Mingjie Wang Zijie li ken Chen Jiatian Mei Shu Zhang key Laboratory of Education Informatization for Nationalities Ministry of EducationYunnan Normal UniversityKunming650000China Yunnan key Laboratory of Smart Education Yunnan Normal UniversityKunming650000China

In the field of intelligent education,the integration of artificial intelligence,especially deep learning technologies,has garnered significant *** tracing(kT)plays a pivotal role in this field by predicting students’future performance through the analysis of historical interaction data,thereby assisting educators in evaluating knowledgemastery and tailoring instructional *** knowledge tracingmethods,largely based on Recurrent Neural Networks(RNNs)and Transformer models,primarily focus on capturing long-term interaction patterns in sequential ***,these models may neglect crucial short-term dynamics and other relevant *** paper introduces a novel approach to knowledge tracing by leveraging a pure Multilayer Perceptron(MLP)*** proposeMixerkT,a knowledge tracing model based on theHyperMixer framework,which uniquely integrates global and localMixer feature *** architecture enables more effective extraction of both long-terminteraction trends and recent learning behaviors,addressing limitations in currentmodels thatmay overlook these key *** evaluations on twowidely-used datasets,ASSIS Tments2009 and Algebra2005,demonstrate that MixerkT consistently outperforms several state-of-the-art models,including DkT,SAkT,and Separated Self-Attentive Neural knowledge Tracing(SAINT).Specifically,MixerkT achieves higher prediction accuracy,highlighting its effectiveness in capturing the nuances of learners’knowledge *** results indicate that our model provides a more comprehensive representation of student learning patterns,enhancing the ability to predict future performance with greater precision.

关键词： knowledge tracing multilayer perceptron channel mixer sequence mixer

Thermally activated delayed fluorescence enhanced by macrocyclization

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Science China Chemistry 2025年

作者： Shuo li Chenghao Zhu lijun Mao Xin Zhang Zecong Ye Chunju li Da Ma School of Pharmaceutical and Chemical Engineering & Institute for Advanced Studies Taizhou University School of Chemical Engineering and light Industry Guangdong University of Technology Tianjin key Laboratory of Structure and Performance for Functional Molecules Tianjin Normal University

Thermally activated delayed fluorescence (TADF) depends on reverse intersystem crossing (RISC) from the lowest triplet to the singlet excited state. Here, a macrocyclization strategy is developed to achieve TADF emission by promoting RISC. 5-(9Hcarbazol-9-yl) isophthalonitrile, a fluorescent molecule, is coupled with 1,4-dimethoxybenzene by methylene bridges to form a macrocycle with TADF emission. Experimental results and theoretical calculation indicate that the macrocyclization strategy contributes to RISC promotion and suppression of nonradiative decay, resulting in effective TADF emission transformed from prompt fluorescence. Three TADF luminophores are cyclized with the same strategy, and an enhanced TADF emission of up to3.8 folds is observed. The marriage of macrocycle chemistry and luminescent materials will provide new guidelines for designing efficient TADF materials.

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Fluorinated poly(p-triphenylene isatin) anion exchange membranes based on hydrophilic hydroxyl side chain modulation for fuel cells

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Journal of Energy Chemistry 2025年第1期100卷 702-709页

作者： Yiman Gu Yanchao Zhang Zhanyu li Yijia Lei Baozeng Sun Xiaoyu Yu Zhe Wang College of Chemistry and life Science Changchun University of Technology College of Chemical Engineering Changchun University of Technology School of Materials Science and Engineering Changchun University of Technology key Laboratory of Advanced Functional Polymer Membrane Materials of Jilin Province

The development of alkaline fuel cells is moving forward at an accelerated pace,and the application of ether-free bonded polymers to anion exchange membranes （AEMs） has been widely ***,the question of the“trade-off”between AEM ionic conductivity and dimensional stability remains *** strategy of inducing microphase separation to improve the performance of AEM has attracted much attention recently,but the design of optimal molecular structures is still being ***,this work introduced different ratios of 3-bromo-1,1,1-trifluoroacetone （x=40,50,and 60） into the main chain of poly（p-terphenylene isatin）.Because fluorinated groups have excellent hydrophobicity,hydrophilic hydroxyl-containing side chains are introduced to jointly adjust the formation of phase separation *** results show that PTI-PTF50-NOH AEM with the appropriate fluorinated group ratio has the best ionic conductivity and alkali stability under the combined effect of *** has an ionic conductivity of 133.83 mS cm-1at 80°*** addition,the OH-conductivity remains at 89%of the initial value at 80°C and 3 M kOH for 1056 h of *** cell polarization curve based on PTI-PTF50-NOH shows a power density of 734.76 mW cm-2at a current density of 1807.7 mA cm-2.

关键词： Potassium hydroxide