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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 369-379页

作者： Mei Zhang Wenhao Li Yangfei Chen Yang Jiang Xiaofei guo Han Dong School of Materials Science and Engineering Shanghai UniversityShanghai 200444China State Key Laboratory of Advanced Special Steel Shanghai UniversityShanghai 200444China

The microstructural evolution of a cold-rolled and intercritical annealed medium-Mn steel(Fe-0.10C-5Mn)was investigated during uniaxial tensile ***-situ observations under scanning electron microscopy,transmission electron microscopy,and X-ray diffraction analysis were conducted to characterize the progressive transformation-induced plasticity process and associated fracture initiation *** findings were discussed with the local strain measurements via digital image *** results indicated that Lüders band formation in the steel was limited to 1.5%strain,which was mainly due to the early-stage martensitic phase transformation of a very small amount of the less stable large-sized retained austenite(RA),which led to localized stress concentrations and strain hardening and further retardation of *** small-sized RA exhibited high stability and progressively transformed into martensite and contributed to a stably extended Portevin-Le Chatelier *** volume fraction of RA gradually decreased from 26.8%to 8.2%prior to *** the late deformation stage,fracture initiation primarily occurred at the austenite/martensite and ferrite/martensite interfaces and the ferrite phase.

关键词： medium-Mn steel retained austenite progressive transformation-induced plasticity effect local strain fracture initiation

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

Ultra‑High Sensitivity Anisotropic Piezoelectric Sensors for Structural Health Monitoring and Robotic Perception

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Nano-Micro Letters 2025年第2期17卷 432-446页

作者： Hao Yin Yanting Li Zhiying Tian Qichao Li Chenhui Jiang Enfu Liang Yiping guo State Key Laboratory of Metal Matrix Composites School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240People’s Republic of China Beijing Vacuum Electronics Research Institute Beijing 100015People’s Republic of China Fundamental Science On Vibration Shock and Noise LaboratoryState Key Laboratory of Mechanical System and VibrationSchool of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240People’s Republic of China

Monitoring minuscule mechanical signals,both in magnitude and direction,is imperative in many application scenarios,e.g.,structural health monitoring and robotic sensing ***,the piezoelectric sensor struggles to satisfy the requirements for directional recognition due to the limited piezoelectric coefficient matrix,and achieving sensitivity for detecting micrometer-scale deformations is also ***,we develop a vector sensor composed of lead zirconate titanate-electronic grade glass fiber composite filaments with oriented arrangement,capable of detecting minute anisotropic *** as-prepared vector sensor can identify the deformation directions even when subjected to an unprecedented nominal strain of 0.06%,thereby enabling its utility in accurately discerning the 5μm-height wrinkles in thin films and in monitoring human pulse *** ultra-high sensitivity is attributed to the formation of porous ferroelectret and the efficient load transfer efficiency of continuous lead zirconate titanate ***,when integrated with machine learning techniques,the sensor’s capability to recognize multi-signals enables it to differentiate between 10 types of fine textures with 100%*** structural design in piezoelectric devices enables a more comprehensive perception of mechanical stimuli,offering a novel perspective for enhancing recognition accuracy.

关键词： Flexible piezoelectric filaments Anisotropic Ultra-high sensitivity Structural health detection Texture recognition

Detection using mask adaptive transformers in unmanned aerial vehicle imagery

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Optoelectronics Letters 2025年第2期21卷 113-120页

作者： YE Huibiao faN Weiming guo Yuping WANG Xuna ZHOU Dalin China Telecommunication Corporation Zhejiang Branch Innovation Center for Smart Medical Technologies & Devices Binjiang Institute of Zhejiang University School of Computing University of Portsmouth

Drone photography is an essential building block of intelligent transportation,enabling wide-ranging monitoring,precise positioning,and rapid ***,the high computational cost of transformer-based methods in object detection tasks hinders real-time result transmission in drone target detection ***,we propose mask adaptive transformer (MAT) tailored for such ***,we introduce a structure that supports collaborative token sparsification in support windows,enhancing fault tolerance and reducing computational *** structure comprises two modules:a binary mask strategy and adaptive window self-attention (A-WSA).The binary mask strategy focuses on significant objects in various complex *** A-WSA mechanism is employed to self-attend for balance perfomance and computational cost to select objects and isolate all contextual *** experiments on the challenging CarPK and VisDrone datasets demonstrate the effectiveness and superiority of the proposed ***,it achieves a mean average precision (mAP@0.5) improvement of 1.25%over car detector based on you only look once version 5 (CD-YOLOv5) on the CarPK dataset and a 3.75%average precision(AP@0.5) improvement over cascaded zoom-in detector (CZ Det) on the VisDrone dataset.

关键词： Drones

Induced neural stem cells regulate microglial activation through Akt-mediated upregulation of CXCR4 and Crry in a mouse model of closed head injury

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Neural Regeneration Research 2025年第5期20卷 1416-1430页

作者： Mou Gao Qin Dong Dan Zou Zhijun Yang Lili guo Ruxiang Xu Department of Neurosurgery Sichuan Academy of Medical Sciences and Sichuan Provincial People’s HospitalSchool of MedicineUniversity of Electronic Science and Technology of ChinaChengduSichuan ProvinceChina Department of Neurosurgery Chinese PLA General HospitalBeijingChina Department of Neurology Fu Xing HospitalCapital Medical UniversityBeijingChina

Microglial activation that occurs rapidly after closed head injury may play important and complex roles in neuroinflammation-associated neuronal damage and *** previously reported that induced neural stem cells can modulate the behavior of activated microglia via CXCL12/CXCR4 signaling,influencing their activation such that they can promote neurological ***,the mechanism of CXCR4 upregulation in induced neural stem cells remains *** this study,we found that nuclear factor-κB activation induced by closed head injury mouse serum in microglia promoted CXCL12 and tumor necrosis factor-αexpression but suppressed insulin-like growth factor-1 ***,recombinant complement receptor 2-conjugated Crry(CR2-Crry)reduced the effects of closed head injury mouse serum-induced nuclear factor-κB activation in microglia and the levels of activated microglia,CXCL12,and tumor necrosis factor-α.Additionally,we observed that,in response to stimulation(including stimulation by CXCL12 secreted by activated microglia),CXCR4 and Crry levels can be upregulated in induced neural stem cells via the interplay among CXCL12/CXCR4,Crry,and Akt signaling to modulate microglial *** agreement with these in vitro experimental results,we found that Akt activation enhanced the immunoregulatory effects of induced neural stem cell grafts on microglial activation,leading to the promotion of neurological recovery via insulin-like growth factor-1 secretion and the neuroprotective effects of induced neural stem cell grafts through CXCR4 and Crry upregulation in the injured cortices of closed head injury ***,these beneficial effects of Akt activation in induced neural stem cells were positively correlated with the therapeutic effects of induced neural stem cells on neuronal injury,cerebral edema,and neurological disorders post–closed head *** conclusion,our findings reveal that Akt activation may enhance the immunoregulatory effects of induced neura

关键词： Akt signaling cerebral edema closed head injury Crry CXCR4 induced neural stem cell microglia neuroinflammation

Unraveling the significance of cobalt on transformation kinetics,crystallography and impact toughness in high-strength steels

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 380-390页

作者： Yishuang Yu Jingxiao Zhao Xuelin Wang Hui guo Zhenjia Xie Chengjia Shang Collaborative Innovation Center of Steel Technology University of Science and Technology BeijingBeijing 100083China School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China

This work reveals the significant effects of cobalt(Co)on the microstructure and impact toughness of as-quenched highstrength steels by experimental characterizations and thermo-kinetic *** results show that the Co-bearing steel exhibits finer blocks and a lower ductile-brittle transition temperature than the steel without ***,the Co-bearing steel reveals higher transformation rates at the intermediate stage with bainite volume fraction ranging from around 0.1 to *** improved impact toughness of the Co-bearing steel results from the higher dense block boundaries dominated by the V1/V2 variant ***,the addition of Co induces a larger transformation driving force and a lower bainite start temperature(BS),thereby contributing to the refinement of blocks and the increase of the V1/V2 variant *** findings would be instructive for the composition,microstructure design,and property optimization of high-strength steels.

关键词： high-strength steel cobalt transformation kinetics crystallography impact toughness

Experimental Study on Energy Storage Characteristics of Sintered Ore Particle Packed Beds

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Journal of Thermal Science 2025年第1期34卷 242-253页

作者： LAI Zhenya DING Liwei LYU Hongkun HOU Chenglong CHEN Jiaying guo Xutao HAN Gaoyan ZHANG Kang State Grid Zhejiang Electric Power Research Institute State Key Laboratory of Clean Energy Utilization Zhejiang University

The particle packed bed energy storage system has advantages such as low costs and wide temperature ranges,which can be combined with solar thermal power generation systems to solve the inherent volatility and discontinuity of renewable *** new materials with low costs and excellent storage performances is one of the eternal research hotspots in the field of energy *** paper innovatively uses sintered ore particles as energy storage material and studies the effect of particle size on the airflow resistance characteristics,energy storage characteristics,and thermocline evolution characteristics of the packed bed through thermal energy storage *** results indicate that for the particles in the macro scale,the smaller the particle,the lower the absolute permeability of the bed and the greater the airflow *** packed bed with smaller particles has a larger specific surface area,larger bulk mass,and smaller bed ***,the packed beds with smaller particles have better thermocline characteristics,less irreversible loss,and can achieve higher thermal efficiency and higher exergy efficiency in the heat storage *** cycle thermal efficiency in packed beds with 25-40 mm,16-25 mm,and 10-16 mm particles is 53.58%,56.27%,and 57.60%,respectively,and the cycle exergy efficiency is 61.81%,69.25%,and 74.13%,***,this paper also studies the effect of discharging airflow rates on thermal storage *** experimental results indicate that suitable discharging strategies should be selected based on different heat demands.

关键词： airflow resistance particle packed bed thermal energy storage thermocline evolution

Molecular dynamics simulation of quartz deformation under slow earthquake background

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Science China Earth Sciences 2025年

作者： Jingxian SUN Qianqian guo Quanlin HOU College of Earth and Planetary Sciences University of Chinese Academy of Sciences Key Laboratory of Computational Geodynamics CAS

Slow earthquakes are the primary mechanism of slow energy release, and research on the focal mechanism has been inconclusive. Studies have primarily focused on the friction law based on physical mechanisms and have suggested that slow earthquakes are caused by brittle faults. However, the focal strength and structural characteristics of slow earthquakes in subduction zones provide evidence of plastic deformation. What is the role of plastic deformation in the focal mechanisms of slow earthquakes? Mechanochemical study have shown that mechanical forces can directly affect chemical bonds. In this study,we examine the storage and release of chemical energy during plastic deformation and consider a mechanochemical process in the focal mechanism of slow earthquakes. Combined with the Tersoff potential, molecular dynamics simulation on the shear deformation process of two α-quartz crystals show that the shear modulus of α-quartz is 18 GPa, and that the crystal model primarily exhibits atoms flowing and changing in the direction of chemical bonds during the steady-state flow stage. The molecular potential energy and stress vary in an oscillating up-and-down curve during shear, indicating that chemical energy can be stored and released during plastic deformation. This is consistent with the energy variation during slow earthquakes. Under the initial simple-shear loading condition, α-quartz crystals undergo general shear deformation instead of plane strain and the angle between the longest instantaneous stretching axis （ISA1） and the shearing direction is approximately 30°, not 45°. Both the deformation type and direction of ISA1are contrary to basic deformation theory, which may provide clues for future *** study reveals the process of quartz elastic-plastic shear deformation on an atomic scale. This information is useful for understanding focal mechanisms of slow earthquakes. This study is part of a series of investigations on tectonic stress chemistry.

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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)

New types of singular solutions of conformal Q-curvature equations

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Acta Mathematica Sinica,English Series 2025年

作者： Zongming guo Zhongyuan Liu fangshu Wan Department of Mathematics Henan Normal University School of Mathematics and Statistics Henan University School of Mathematical Sciences Anhui University

We construct radial and non-radial singular solutions u ∈ C4（B{0}） with a non-removable singular point x = 0 for the conformal Q-curvature equation:■where B = {x ∈ R4: |x| D0≥ 0, and satisfying ■Moreover, detailed asymptotic expansions near x = 0 of these radial and non-radial singular solutions can be established. As an application, we can also obtain the existence of two types of solutions u ∈ C4（R4■） to the problem ■ satisfying |x|-2u（x） →-D D0, and satisfying u（x） = o（|x|2） uniformly as |x| → ∞.

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