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2:17-type SmCo permanent magnets with controllable remanence temperature coefficients via substitution of heavy rare earth elements

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Rare Metals 2024年第8期43卷 3990-3996页

作者： Jia-Yi Huang Shu-Lan Zuo Qi Zhang Hong-Yang Dai Lei Yang Jing-Hua Liu Cheng-Bao Jiang Key Laboratory of Aerospace Materials and Performance(Ministry of Education) School of Materials Science and EngineeringBeihang UniversityBeijing 100191China

Permanent magnets that can maintain a constant magnetic flux over a wide temperature range are highly desirable in certain applications such as precision instruments.2:17-type SmCo permanent magnets are promising for such instruments owing to their excellent high-temperature magnetic properties that can be further manipulated byadding heavy rare earth elements (HREs).

关键词： magnets permanent earth

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Selective oxidation of emerging organic contaminants in heterogeneous Fenton-like systems

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Nano Research 2024年第11期17卷 9300-9325页

作者： Sheng Wang Yuxin Lu Shangkun Pei Xiang Li Bo Wang Key Laboratory of Cluster Science Ministry of Education Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials Advanced Technologies Research Institute (Jinan) Advanced Research Institute of Multidisciplinary Science School of Chemistry and Chemical Engineering Beijing Institute of Technology Beijing 100081 China

Heterogeneous Fenton-like reaction shows great potential for eliminating organic substances (e.g. emerging organic contaminants (EOCs)) in water, which has been widely explored in recent decades. However, the catalytic mechanisms reported in current studies are extremely complicated because multiple mechanisms coexist and contribute to the removal efficiencies. Most importantly, heterogeneous systems show selective oxidation properties, which are crucial for improving the efficiencies in the catalytic elimination of organic substances. Thus, this critical review summarizes and compares the diverse existing mechanisms (non-radical and radical pathways) in heterogeneous catalytic processes based on recent studies. The typical oxidation mechanisms during selective advanced oxidation of EOCs were systematically discussed based on the following sections, including the selective adsorption and generation of reactive oxygen species (ROS) in photo/electron-Fenton and Fenton-like systems. Moreover, the non-radical pathways are discussed in depth by the singlet oxygen, high-valent metal-oxo, electron transfer process, etc. Moreover, the direct oxidative transfer process for the removal of EOCs was introduced in recent studies. Finally, the cost, feasibility as well as the sustainability of heterogeneous Fenton-like catalysts are summarized. This review offers useful guidance for developing suitable strategies to develop materials for decomposing the organic substrates.

关键词： emerging organic contaminants heterogeneous advanced oxidation process heterogeneous activators selectivity

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Effect of Curing Age on Tensile Properties of Fly Ash Based Engineered Geopolymer Composites(FA-EGC)by Uniaxial Tensile Test and Ultrasonic Pulse Velocity Method

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Journal of Wuhan University of Technology(materials science) 2023年第6期38卷 1319-1325页

作者： GUO Xiaolu LI Shuyue Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education Tongji UniversityShanghai 201804China School of Materials Science and Engineering Tongji UniversityShanghai 201804China

Tensile properties of fly ash based engineered geopolymer composites(FA-EGC)at different curing ages were studied by uniaxial tensile test and ultrasonic pulse velocity(UPV)methods,which included uniaxial tensile properties,the correlation between ultrasonic pulse velocity and tensile properties,and characteristic parameters of *** experimental results show that obvious strain hardening behavior can be found in FA-EGC at different curing *** the increase of curing age,the tensile strength increases,the tensile strain decreases and the toughness becomes *** UPV of FA-EGC increases with curing age,and a strong correlation can be found between tensile strength and *** the increase of curing age,the average crack width of FA-EGC decreases and the total number of cracks *** is because the strength of geopolymer increases fast at early age,thus the later strength development of FA-EGC tend to be *** the same time,the bond strength between fiber and matrix,and the friction of fiber/matrix interface continue to increase with curing age,thus the bridging effect of fiber is gradually *** conclusion,the increase of curing age is beneficial to the development of tensile properties of FA-EGC.

关键词： engineered geopolymer composites(EGC) tensile properties ultrasonic pulse velocity(UPV) characteristic parameters of microcracks

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Microstructure,microchemistry,and micro-magnetism of dysprosium grain boundary diffused(Nd,Ce)-Fe-B magnets

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Journal of Rare Earths 2025年第3期43卷 556-568,I0005页

作者： Yifei Xiao Lele Zhang Tao Liu Qisong Sun Xiaolong Song Yikun Fang Anhua Li Minggang Zhu Wei Li Division of Functional Materials Central Iron and Steel Research InstituteBeijing 100081China Key Laboratory of Advanced Functional Materials Ministry of Education of ChinaCollege of Materials Science and EngineeringBeijing University of TechnologyBeijing 100124China

The microstructure of(Nd,Ce)-Fe-B sintered magnets with different diffusion depths was characterized by a magnetic force microscope,and the relationship between the magnetic properties and the local structure of grain boundary diffused magnets is *** domains perpendicular to the c-axis(easy magnetization direction)show a typical maze-like pattern,while those parallel to the c-axis show the characte ristics of plate *** significant gradient change is shown in the concentration of Dy with the direction of diffusion from the surface to the *** diffuses along grain boundaries and(Dy,Nd)_(2)Fe_(14)B layer with a high anisotropy field formed around the *** in-situ electron probe micro-analysis/magnetic force microscopy(EPMA/MFM),it is found that the average domain width decreases,and the proportion of single domain grains increases as diffusion depth *** is caused by both the change of concentration and distribution of *** grain boundary diffusion process changes the microstructure and microchemistry inside the magnet,and these local magnetism differences can be reflected by the configuration of the magnetic domain structure.

关键词： Magnetic microstructures (Nd,Ce)-Fe-B Rare earths Magnetic force microscope Grain boundary diffusion process(GBDP) In-situ

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Formation and properties of a Zr-based amorphous coating by laser cladding

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Rare Metals 2024年第4期43卷 1809-1814页

作者： Ning Zhang Ying Liu Wei Yang Shu-Jie Pang Key Laboratory of Aerospace Materials and Performance(Ministry of Education) School of Materials Science and EngineeringBeihang UniversityBeijing100191China

(Zr_(0.53)Al_(0.1)Ni_(0.05)Cu_(0.3)Ti_(0.02))_(99)Y_1(at%)coating with amorphous layer of about 180μm thick was prepared on a steel substrate by using laser cladding *** coating is compact and shows good metallurgical bonding with *** microstructure,microhardness and corrosion behavior along the depth from the coating surface to the substrate were *** is found that a gradient structure consisted of amorphous surface layer,amorphous-crystalline transitional layer and substrate is formed after the laser *** microhardness and corrosion behavior exhibit variation with the microstructural evolution at different depths from the coating *** microhardness and corrosion resistance in 3.5 wt%NaCl solution of the amorphous surface layer are comparable to those of the as-cast Zr-based BMG with the same composition,and higher than those of the steel substrate.

关键词： Laser cladding Amorphous coating Microstructure Hardness Corrosion resistance

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Double effects of recrystallization behavior on grain morphology evolution and mechanical properties of Al/Mg/Al composite plate by hard plate rolling

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Progress in Natural science:materials International 2024年第5期34卷 1029-1038页

作者： Jia Yang Zhang Feng Li Fu Wei Kang Zi Yi Wang Lu Sun School of Materials Science and Chemical Engineering Harbin University of Science and Technology Key Laboratory of Advanced Manufacturing and Intelligent Technology Ministry of Education Harbin University of Science and Technology Heilongjiang Provincial Key Laboratory of Light Metal Materials Modification & Green Forming Technology Harbin University of Science and Technology

Enhancing the bonding strength, optimizing the microstructure and refining the properties represent effective strategies for the fabrication of heterogeneous composite plates. In this study, composite plates of Al/Mg/Al were fabricated through hard plate rolling(HPR) with a reduction in rolling ranging from 40 % to 80 %. The research primarily concentrates on the substrate in the influence of rolling dynamic recrystallization(DRX) behavior on the grain morphology evolution and mechanical properties of AZ31 magnesium alloy sheets during the process. The findings indicate that at a compression amount of 60 %, the composite plate exhibits an ultimate tensile strength(UTS), a maximum elongation(EL) of 12.5 %, and improved interface bonding. Comparative analysis reveals the occurrence of DRX on the Mg side, resulting in the formation of small DRXed grains being generated. With an increase in reduction, DRX is facilitated, leading to an initial rise and subsequent decline in the proportion of DRXed grains. The proliferation of fine grains hinder dislocation movement, thereby reinforcing composite ***, an elevation in the degree of recrystallization enhances the initiation of non-basal slip and enhances the plasticity of sheet metal. This study offers valuable scientific guidance and technical assistance for the production of forming high-quality Mg–Al composite plates.

关键词： Hard plate rolling Al/Mg/Al Composite plate Dynamic recrystallization Mechanical properties

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Superior piezoelectric performance with high operating temperature in bismuth ferrite-based ternary ceramics

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Journal of materials science & Technology 2024年第2期169卷 172-181页

作者： Yunyao Huang Leiyang Zhang Ruiyi Jing Yang Yang Vladimir Shur Xiaoyong Wei Li Jin Electronic Materials Research Laboratory Key Laboratory of the Ministry of EducationSchool of Electronic Science and EngineeringXi’an Jiaotong UniversityXi’an 710049China Faculty of Materials and Manufacturing Key Laboratory of Advanced Functional MaterialsEducation Ministry of ChinaBeijing University of TechnologyBeijing 100124China School of Natural Sciences and Mathematics Ural Federal UniversityEkaterinburg620000Russia

Due to the thermal depolarization effect,adequate piezoelectric performance with high operating temperature is regarded to be challenging to accomplish concurrently in piezoceramics for applications in specific piezoelectric *** this work,we synthesized(0.8−x)BiFeO_(3)-x PbTi_(3)-0.2Ba(Zr_(0.25)Ti_(0.75))O_(3)(abbreviated as BFO-x PT-BZT)ternary solid solutions with 0.15≤x≤0.30 by conventional solid-state reaction *** MPB composition with a coexisting state of rhombohedral-tetragonal phases exhibits enhanced electromechanical properties,including Curie temperature of 380℃,large-signal equivalent piezoelectric coefficient d^(∗)_(33)of 395 pm V^(-1),small-signal piezoelectric coefficient d_(33)of 302 pC N^(-1),and electromechanical coupling factor k_(p)of 50.2%,which is comparable to commercial PZT-5A ceramics,indicating potential in high-temperature ***,in-situ X-ray diffraction(XRD)and piezoelectric force microscopic(PFM)techniques demonstrate that multiphase coexistence and complex nanodomains promote piezoelectric response via *** x=0.24 composition exhibits the highest in-situ d_(33)of 577 pC N^(-1)and good temperature stability in 30−280℃,indicating that BZT-modified BFO-PT ceramics are promising candidates for high-temperature piezoelectric devices.

关键词： High-temperature piezoelectrics Morphotropic phase boundary In-situ technique Domain structure BFO

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Identification of the highly active Zn-N_(4) sites with pyrrole/pyridine-N synergistic coordination by dz^(2)+s-band center for electrocatalytic H_(2)O_(2) production

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Journal of Energy Chemistry 2024年第11期98卷 105-113页

作者： Rui Chen Wei Liu Zhiyuan Sang Jingjing Jia Zhenxin Li Jiahuan Nie Qiao Jiang Zixian Mao Baitong Guo Qiuying Wang Feng Hou Lichang Yin De'an Yang Ji Liang Key Laboratory of Advanced Ceramics and Machining Technology of Ministry of Education School of Materials Science and Engineering Tianjin UniversityTianjin 300072China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of ScienceShenyang 110016LiaoningChina

Single metal atoms anchored on nitrogen-doped carbon materials(M-N_(4))have been identified as effective active sites for catalyzing the two-electron oxygen reduction reaction(2e-ORR).However,the relationship between the local atomic/electronic environments of the M-N_(4) sites(metal atoms coordinated with different types of N species)and their catalytic activity for 2e-ORR has rarely been elaborated clearly,which imposes significant ambiguity for the rational design of ***,guided by the comprehensive density-functional theory calculations and predictions,a series of Zn-N_(4) single-atom catalysts(SACs)are designed with pyrrole/pyridine-N(N_(Po)/N_(Pd))synergistic coordination and prepared by controlling the pyrolysis temperature(600,700,and 800℃),Among them,the dominated Zn-N_(4) configurations with rationally combined N_(Po)/N_(Pd)coordination show~*OOH adsorption strength close to the optimal value,much superior to those with mono N ***,the as-prepared catalyst exhibits a high H_(2)O_(2) selectivity of over 90%both in neutral and alkaline environments,with a superb H_(2)O_(2) yield of up to 33.63 mol g^(-1)h^(-1)in an alkaline with flow *** importantly,a new descriptor,dz^(2)+s band center,has been proposed,which is especially feasible for predicting the activity for metal types with fully occupied s and d *** work thus presents clear guidance for the rational design of highly active SACs toward ORR and provides a complement to the d-band theory for more accurately predicting the catalytic activity of the materials.

关键词： Zinc single-atom catalysts Hydrogen peroxide Local coordination environments d+s-Band modulation

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Editable semiconductor photo-electrodes for sustainable ammonia synthesis

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Nano Research 2024年第4期17卷 3107-3112页

作者： Ning Lan Kun Du Erling Zhao Wei Zhao Tao Ling Key Laboratory for Advanced Ceramics and Machining Technology of Ministry of Education Institute of New-EnergySchool of Materials Science and EngineeringTianjin UniversityTianjin 300072China School of Materials Science and Engineering Tianjin Chengjian UniversityTianjin 300384China

Powered by an inexhaustible supply of solar energy,photoelectrochemical(PEC)nitrogen reduction reaction(NRR)provides an ideal solution for the synthesis of green ammonia(NH_(3)).Although great efforts have been made in the past decades,there are still significant challenges in increasing the NH_(3) yields of the PEC-NRR *** addition to the issues of low activity and selectivity similar to electrochemical NRR,the progress of PEC-NRR is also impeded by the limited increase in NH_(3) yields as the electrode is ***,we propose an editable electrode design strategy that parallels unit photo-electrodes to achieve a linear increase in NH_(3) yields with electrode active *** demonstrate that the editable electrode design strategy minimizes the electrode charge transfer resistance,allowing more photo-generated carriers to reach the electrode surface and promote the catalytic *** believe that this editable electrode design strategy provides an avenue to achieve sustainable PEC NH_(3) production.

关键词： editable electrode photoelectrochemical nitrogen reduction reaction parallel electrode ZnSe

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A novel MgF2/PDA/S-HA coating on the bio-degradable ZE21B alloy for better multi-functions on cardiovascular application

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Journal of Magnesium and Alloys 2023年第2期11卷 480-492页

作者： Yang Yu Shi-Jie Zhu Hao-Tian Dong Xue-Qi Zhang Jing-An Li Shao-Kang Guan School of Materials Science and Engineering&Henan Key Laboratory of Advanced Magnesium Alloy&Key Laboratory of Materials Processing and Mold Technology(Ministry of Education) Zhengzhou UniversityZhengzhou 450001China

Recently, functional molecules such as Polydopamine(PDA), Hyaluronic Acid(HA) and heparin have been widely studied in the field of surface modification of magnesium(Mg) alloy stents for better degradation behavior and biocompatibility, but their further application is limited by undesirable anticoagulant function, uncontrollable degradation and easy bleeding, *** to this consideration, a magnesium Fluoride/Polydopamine/Sulphonated hyaluronic acid(Mg F2/PDA/S-HA) composite coating was successfully prepared by applying S-HA with sulfur content of 9.71 wt% on the surface of ZE21B alloy in this study. The results showed that the composite coating with a unique mesh structure not only inherited the anticoagulant effect of sulfonic acid group and the excellent cyto-compatibility of S-HA with high sulfur content, but also significantly improved the corrosion performance of ZE21B *** results indicate a great application potential of the composite coating in the field of cardiovascular biomaterials.

关键词： Bio-degradable magnesium alloy Cardio-vascular stents Composite coating Sulphonated hyaluronic acid

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