Soft magnetic alloys are extensively used in various power electronic devices due to their advantageous properties,including high saturation magnetic induction,low coercivity,and high permeability.In certain applicati...Soft magnetic alloys are extensively used in various power electronic devices due to their advantageous properties,including high saturation magnetic induction,low coercivity,and high permeability.In certain applications,complex-shaped components are increasingly required for performance enhancement.Additive manufacturing technique,particularly selective laser melting(SLM),has emerged as an effective method for fabricating such complex-shaped soft magnetic components.SLM,a laserbased additive manufacturing technique,employs high-power-density lasers to melt and fuse metal powders within a powder bed selectively.This approach enables rapid prototyping,precise geometrical control,and the integration of multi-material designs.This review highlights recent advancements in the application of SLM technique for the production of soft magnetic alloys,focusing on Fe-Si,Fe-Ni,Fe-Co,and amorphous alloy systems.Moreover,it explores the implementation of SLM in manufacturing processes and evaluates both the opportunities and challenges associated with SLM-based production of soft magnetic alloys.展开更多
Layered transition-metal compounds(LTMCs)feature stacked architectures,strong magnetic anisotropy,and tunable magnetic order,making them promising material platforms for low-power spintronic technologies and for enabl...Layered transition-metal compounds(LTMCs)feature stacked architectures,strong magnetic anisotropy,and tunable magnetic order,making them promising material platforms for low-power spintronic technologies and for enabling topological functionalities in the post-Moore era.Here we review recent progress on two-dimensional(2D)magnetism in LTMCs,emphasizing material taxonomy,intrinsic magnetic properties,and external-field controls.This review first presents a classification of LTMCs by crystal structure and chemistry—binary halides,chalcogenides,and ternary families(e.g.,MPX_(3),M_(m)X_(n)Te_(k),MnBi_(2)Te_(4))—followed by a summary of their coupling mechanisms,ordering temperatures,and dimensional effects.It then analyzes the modulation of exchange interactions,magnetic anisotropy,and topological states by electric-field gating,strain engineering,and ion intercalation,with representative experimental demonstrations.Notable advances include room-temperature ferromagnetic metals and semiconductors,observation of the quantum anomalous Hall effect(QAHE)in MnBi2Te4,and synergistic control of magnetic-topological states under multiple external stimuli.Persistent challenges involve the limited availability of intrinsic 2D magnetic semiconductors with high Curie temperatures(Tc),incomplete understanding of the microscopic couplings at interfaces and under quantum confinement,and device-level stability.We conclude by outlining opportunities that lie in the integration of multiscale characterization,first-principles theory,and cross-scale fabrication to precisely co-engineer magnetism,topology,and electronic structure,thereby advancing LTMCs toward spintronic and topological-quantum applications.展开更多
In this study,a multifunctional aptamer-conjugated magnetic covalent organic framework(COF)-CuO/Au nanozyme(MCOF-CuO/Au@apt)was developed as a“three-in-one”platform for dual-signal colorimetric and fluorescent detec...In this study,a multifunctional aptamer-conjugated magnetic covalent organic framework(COF)-CuO/Au nanozyme(MCOF-CuO/Au@apt)was developed as a“three-in-one”platform for dual-signal colorimetric and fluorescent detection of Vibrio parahaemolyticus.The nanozyme integrated magnetic separation,peroxidase-like catalytic activity,and specific target recognition through an aptamer-based strategy.Upon binding to V.parahaemolyticus,the catalytic oxidation of tetra-aminophenylethylene(TPE-4A)by the nanozyme was selectively inhibited,resulting in distinct colorimetric and fluorescent signals that significantly enhanced the detection accuracy and reliability.The proposed method exhibited high sensitivity,with limits of detection(LOD)of 21 and 7 CFU/mL for the colorimetric and fluorescent assays,respectively.The performance of this method was validated using real seafood samples,including Penaeus vannamei,Mytilus coruscus,and Crassostrea gigas,which showed high recovery rates(101.11%-107.30%)and excellent reproducibility.The system also demonstrated strong specificity and accuracy under various conditions,confirming its robustness and practical applicability.Collectively,this innovative platform presents a promising solution for the rapid,versatile,and sensitive detection of V.parahaemolyticus in seafood,with considerable potential to advance food safety diagnosis and on-site monitoring.展开更多
Dissimilar AZ31B magnesium alloy and DC56D steel were welded via AA1060 aluminum alloy by magnetic pulse welding.The effects of primary and secondary welding processes on the welded interface were comparatively invest...Dissimilar AZ31B magnesium alloy and DC56D steel were welded via AA1060 aluminum alloy by magnetic pulse welding.The effects of primary and secondary welding processes on the welded interface were comparatively investigated.Macroscopic morphology,microstructure,and interfacial structure of the joints were analyzed using scanning electron microscope,energy dispersive spectrometer,and X-ray diffractometer(XRD).The results show that magnetic pulse welding of dissimilar Mg/Fe metals is achieved using an Al interlayer,which acts as a bridge for deformation and diffusion.Specifically,the AZ31B/AA1060 interface exhibits a typical wavy morphology,and a transition zone exists at the joint interface,which may result in an extremely complex microstructure.The microstructure of this transition zone differs from that of AZ31B magnesium and 1060 Al alloys,and it is identified as brittle intermetallic compounds(IMCs)Al_(3)Mg_(2) and Al_(12)Mg_(17).The transition zone is mainly distributed on the Al side,with the maximum thickness of Al-side transition layer reaching approximately 13.53μm.Incomplete melting layers with varying thicknesses are observed at the primary weld interface,while micron-sized hole defects appear in the transition zone of the secondary weld interface.The AA1060/DC56D interface is mainly straight,with only a small number of discontinuous transition zones distributed intermittently along the interface.These transition zones are characterized by the presence of the brittle IMC FeAl_(3),with a maximum thickness of about 4μm.展开更多
Chiral magnets have attracted considerable attention due to their intricate magnetic properties,among which B20compounds constitute a quintessential class that has gained significant focus,particularly in the study of...Chiral magnets have attracted considerable attention due to their intricate magnetic properties,among which B20compounds constitute a quintessential class that has gained significant focus,particularly in the study of skyrmions.MnGe,as a member of the B20 family,exhibits a more complex magnetic structure compared with other materials with similar crystal structures.In this work,we successfully synthesized high-quality MnGe thin films and characterized their magnetoresistance,M-H curves,magneto-Seebeck effect,and magnetic force microscopy(MFM)images,all of which demonstrate pronounced magnetic anisotropy.Notably,the Seebeck coefficient exhibits a plateau at low magnetic fields when the magnetic field is applied in the film plane,indicating a field region in which the magnetic structure remains stable.MFM imaging further reveals magnetic transitions within the MnGe films when the magnetic field is oriented along the film plane.These findings are crucial for advancing our understanding of the magnetic ground state of MnGe and the evolution of its magnetic structure under an applied external magnetic field.展开更多
T he residual stray magnetic fields present in ferromagnetic casting slabs were investigated in this work,which result from the magnetic fields generated during the steel casting process.Existing optical detection met...T he residual stray magnetic fields present in ferromagnetic casting slabs were investigated in this work,which result from the magnetic fields generated during the steel casting process.Existing optical detection methods face challenges owing to surface oxide scales,and conventional high-precision magnetic sensors are ineffective at high temperatures.To overcome these limitations,a small coil sensor was employed to measure the residual magnetism strength in oscillation traces,using metal magnetic memory and electromagnetic induction methods,which can carry out detection without an external excitation source.Using this technology,the proposed scheme successfully detects defects at high tempe-ratures(up to 670℃)without a cooling device.The key findings include the ability to detect both surface and near-surface defects,such as cracks and oscillation marks,with an enhanced signal-to-noise ratio(SNR)of 7.2 dB after signal processing.The method’s practicality was validated in a steel mill environment,where testing on casting slabs effectively detected defects,providing a foundation for improving industrial quality control.The proposed detection scheme offers a significant advancement in nondestructive testing(NDT)for high-temperature applications,contributing to more efficient and accurate monitoring of ferromagnetic material integrity.展开更多
Under hydrothermal and solvothermal conditions,two novel cobalt-based complexes,{[Co_(2)(CIA)(OH)(1,4-dtb)]·3.2H_(2)O}n(HU23)and{[Co_(2)(CIA)(OH)(1,4-dib)]·3.5H2O·DMF}n(HU24),were successfully construct...Under hydrothermal and solvothermal conditions,two novel cobalt-based complexes,{[Co_(2)(CIA)(OH)(1,4-dtb)]·3.2H_(2)O}n(HU23)and{[Co_(2)(CIA)(OH)(1,4-dib)]·3.5H2O·DMF}n(HU24),were successfully constructed by coordinatively assembling the semi-rigid multidentate ligand 5-(1-carboxyethoxy)isophthalic acid(H₃CIA)with the Nheterocyclic ligands 1,4-di(4H-1,2,4-triazol-4-yl)benzene(1,4-dtb)and 1,4-di(1H-imidazol-1-yl)benzene(1,4-dib),respectively,around Co^(2+)ions.Single-crystal X-ray diffraction analysis revealed that in both complexes HU23 and HU24,the CIA^(3-)anions adopt aκ^(7)-coordination mode,bridging six Co^(2+)ions via their five carboxylate oxygen atoms and one ether oxygen atom.This linkage forms tetranuclear[Co4(μ3-OH)2]^(6+)units.These Co-oxo cluster units were interconnected by CIA^(3-)anions to assemble into 2D kgd-type structures featuring a 3,6-connected topology.The 2D layers were further connected by 1,4-dtb and 1,4-dib,resulting in 3D pillar-layered frameworks for HU23 and HU24.Notably,despite the similar configurations of 1,4-dtb and 1,4-dib,differences in their coordination spatial orientations lead to topological divergence in the 3D frameworks of HU23 and HU24.Topological analysis indicates that the frameworks of HU23 and HU24 can be simplified into a 3,10-connected net(point symbol:(4^(10).6^(3).8^(2))(4^(3))_(2))and a 3,8-connected tfz-d net(point symbol:(4^(3))_(2)((4^(6).6^(18).8^(4)))),respectively.This structural differentiation confirms the precise regulatory role of ligands on the topology of metal-organic frameworks.Moreover,the ultraviolet-visible absorption spectra confirmed that HU23 and HU24 have strong absorption capabilities for ultraviolet and visible light.According to the Kubelka-Munk method,their bandwidths were 2.15 and 2.08 eV,respectively,which are consistent with those of typical semiconductor materials.Variable-temperature magnetic susceptibility measurements(2-300 K)revealed significant antiferromagnetic coupling in both complexes,with their effective magnetic moments decreasing markedly as the temperature lowered.CCDC:2457554,HU23;2457553,HU24.展开更多
In recent years,the rising incidence of gastrointestinal(GI)cancer has triggered an urgent need for effective early intervention strategies.Traditional endoscopic techniques often cause patient discomfort,and it is di...In recent years,the rising incidence of gastrointestinal(GI)cancer has triggered an urgent need for effective early intervention strategies.Traditional endoscopic techniques often cause patient discomfort,and it is difficult to navigate deep regions of complex organ structures.This work proposes a kind of bio-inspired magnetic soft robot(BMSR)to address these challenges.The design of the BMSRs is inspired by the rolling motion of the golden wheel spider.Two six-degree-of-freedom(6-DOF)robotic arms are used,where one arm is responsible for real-time manipulation of the BMSRs,and the other is dedicated to monitoring their status.Under the actuation of an external rotating magnetic field,the BMSRs can flexibly climb on inclined surfaces at any angle,involving the inverted surface.Through the powerful output force,the BMSRs can overcome the mobility barrier induced by different human organs,including mucus,folds,and height differences of up to 8 cm.Such an exceptional mobility enables the BMSRs to deliver drugs in the targeted complex GI environment.Moreover,in combination with an endoscope,it provides real-time visual feedback for precise navigation.In vitro animal experiments validate the feasibility of BMSRs,paving a way for their usage in minimally invasive GI treatment.This work advances the potential applications of magnetic soft robots in the biomedical field.展开更多
The spin-sensitive nature of redox reactions in energy conversion systems,such as the oxygen evolution reaction(OER),has attracted increasing attention due to its potential for enhancing catalytic efficiency.Magnetic ...The spin-sensitive nature of redox reactions in energy conversion systems,such as the oxygen evolution reaction(OER),has attracted increasing attention due to its potential for enhancing catalytic efficiency.Magnetic fields(MFs)have been proposed to enhance OER performance by influencing the spin states of oxygen intermediates.However,prior study has predominantly focused on MF effects mediated by the intrinsic magnetic properties of electrocatalysts or magnetohydrodynamics.In this work,we report a universal enhancement in OER activity,achieving over 150% increase in current density under a200 mT MF across diamagnetic,paramagnetic and magnetic electrocatalysts in 1 M KOH.Through systematic investigation of MF orientation and strength,pH,applied potentials,and the use of benzoquinone radical scavenger,we demonstrate that MF-driven performance improvements arise from direct modulation of oxygen radical spin states.Specifically,MFs promote the formation of spin-triplet oxygen intermediates(↑O–O↑),a critical step for O–O bond formation,independent of the catalyst's intrinsic magnetism.However,the local magnetic environment near the catalyst surface,governed by its magnetic properties,indirectly influences radical spin dynamics by alternating the effective field experienced by intermediates.These findings redefine the role of spin manipulation in electrocatalysis,advancing understanding of MF-driven spin effects in redox reactions.展开更多
The Circular Electron Positron Collider(CEPC)proposed in China is a dual-ring collider with electron and positron beams in the energy range of 45.5–180 GeV.The main dipole in the CEPC collider is a dual-aperture dipo...The Circular Electron Positron Collider(CEPC)proposed in China is a dual-ring collider with electron and positron beams in the energy range of 45.5–180 GeV.The main dipole in the CEPC collider is a dual-aperture dipole with a shared coil between the two apertures,forming an I-shaped structure that can reduce power consumption by 50%.Because of its long length and low field strength,the development of this dual-aperture magnet faces challenges regarding its mechanical design,field measurement accuracy,and field performance.Numerical simulations were performed to better understand the Earth's field and the effect of different BH curves on field performance.The field results of the prototype are presented herein,and the field quality satisfies the requirements.The remanent field accounts for 2%of the integral field at 140 Gs,and the hysteresis effect caused an increase in field strength of approximately 0.075%after a standardization cycle of the trim coils.Research on this prototype can provide useful insights for understanding low-field dipole magnets.展开更多
The National Geophysical Data Center(NGDC)of the United States has collected aeromagnetic data for input into a series of geomagnetic models to improve model resolution;however,in the Tibetan Plateau region,ground-bas...The National Geophysical Data Center(NGDC)of the United States has collected aeromagnetic data for input into a series of geomagnetic models to improve model resolution;however,in the Tibetan Plateau region,ground-based observations remain insufficient to clearly reflect the characteristics of the region’s lithospheric magnetism.In this study,we evaluate the lithospheric magnetism of the Tibetan Plateau by using a 3D surface spline model based on observations from>200 newly constructed repeat stations(portable stations)to determine the spatial distribution of plateau geomagnetism,as well as its correlation with the tectonic features of the region.We analyze the relationships between M≥5 earthquakes and lithospheric magnetic field variations on the Tibetan Plateau and identify regions susceptible to strong earthquakes.We compare the geomagnetic results with those from an enhanced magnetic model(EMM2015)developed by the NGDC and provide insights into improving lithospheric magnetic field calculations in the Tibetan Plateau region.Further research reveals that these magnetic anomalies exhibit distinct differences from the magnetic-seismic correlation mechanisms observed in other tectonic settings;here,they are governed primarily by the combined effects of compressional magnetism,thermal magnetism,and deep thermal stress.This study provides new evidence of geomagnetic anomalies on the Tibetan Plateau,interprets them physically,and demonstrates their potential for identifying seismic hazard zones on the Plateau.展开更多
We report the development of the[Pt_(0.75)Ti_(0.25)/Co-Ni multilayer/Ta]_n superlattice with strong spin-orbit torque,large perpendicular magnetic anisotropy,and remarkably low switching current density.We demonstrate...We report the development of the[Pt_(0.75)Ti_(0.25)/Co-Ni multilayer/Ta]_n superlattice with strong spin-orbit torque,large perpendicular magnetic anisotropy,and remarkably low switching current density.We demonstrate that the efficiency of the spin-orbit torque increases nearly linearly with the repetition number n,which is in excellent agreement with the spin Hall effect of the Pt_(0.75)Ti_(0.25)being essentially the only source of the observed spin-orbit torque.The perpendicular magnetic anisotropy field is also substantially enhanced by more than a factor of 2 as n increases from 1 to6.The[Pt_(0.75)Ti_(0.25)/Co-Ni multilayers/Ta]_n superlattice additionally exhibits deterministic,low-current-density magnetization switching despite the very large total layer thicknesses.The unique combination of strong spin-orbit torque,robust perpendicular magnetic anisotropy,low-current-density switching,and excellent high thermal stability makes the[Pt_(0.75)Ti_(0.25)/Co-Ni multilayer/Ta]_n superlattice a highly compelling material candidate for ultrafast,energy-efficient,and long-data-retention spintronic technologies.展开更多
Large magnetic entropy change(△S_(M))can realize a prominent heat transformation under the magnetic field and directly strengthen the efficacy of the magnetocaloric effect,which provides a pioneering environmentally ...Large magnetic entropy change(△S_(M))can realize a prominent heat transformation under the magnetic field and directly strengthen the efficacy of the magnetocaloric effect,which provides a pioneering environmentally friendly solidstate strategy to improve refrigeration capacities and efficiencies.The second-order magnetic transition(SOMT)materials have broader△S_(M) peaks without thermal hysteresis,making them highly attractive in magnetic refrigeration,especially in the room temperature range.Here,we report a significant enhancement of△S_(M) at room temperature in single-crystal Mn_(5)Ge_(3).In this SOMT system,we realize a 60%improvement of-△S_(M)^(max) from 3.5 J/kg·K to 5.6 J/kg·K at T=300 K.This considerable enhancement of△S_(M) is achieved by intentionally introducing strain energy through high-pressure constrained deformation.Both experimental results and Monte Carlo simulations demonstrate that the enhancement of△S_(M) originates from the microscopic strain and lattice deformation induced by strain energy after deformation.This strain energy will reconstruct the energy landscape of this ferromagnetic system and enhance magnetization,resulting in a giant intensity of magnetocaloric responses.Our findings provide an approach to increase magnetic entropy change and may give fresh ideas for exploring advanced magnetocaloric materials.展开更多
Magnetic field-driven spin polarization modulation has emerged as an effective way to boost the electrocatalytic oxygen evolution reaction(OER).However,the correlation among catalyst structure,magnetic property,and ma...Magnetic field-driven spin polarization modulation has emerged as an effective way to boost the electrocatalytic oxygen evolution reaction(OER).However,the correlation among catalyst structure,magnetic property,and magnetic field enhanced-electrochemical activity remains to be fully elucidated.Herein,single-domain CoFe_(2)O_(4) catalysts with tunable oxygen vacancies(CFO-V_(O)) were synthesized to probe how V_(O) mediates magnetism and OER activity under magnetic field.The introduction of V_(O) can simultaneously modulate saturation magnetization(M_(s)) and coercivity(H_(c)),where the increased M_(s) dominates the magnetic field-enhanced OER activity.Under a 14,000 G magnetic field,the optimized CFO-V_(O) exhibits up to 16.1 % reduction in overpotential and 365 % enhancement in magnetocurrent(MC).Electrochemical analyses and post-OER characterization reveal that the magnetic field synergistically improves OER kinetics through lattice distortion induction,magnetohydrodynamic effect,and spin charge transfer effect.Importantly,the magnetic field promotes additional Co^(3+) generation to compensate for charge imbalance caused by V_(O) filling,maintaining dynamic equilibrium of V_(O) and effective reactant adsorption-conversion processes.This work unveils the synergistic mechanism of V_(O) and magnetic parameters for enhancing OER performance under the magnetic field,providing new insights into the design of high-efficiency spinregulated OER catalysts.展开更多
Oxygen carriers play a fundamental role in chemical looping combustion(CLC).Iron-based carriers have been extensively investigated owing to their abundance and environmentally friendly.However,the reactivity and separ...Oxygen carriers play a fundamental role in chemical looping combustion(CLC).Iron-based carriers have been extensively investigated owing to their abundance and environmentally friendly.However,the reactivity and separability of iron-based carriers require further enhancement.This study investigates the effect of the concentration of Mn doping on reactivity,elastic properties and magnetic properties based on density functional theory(DFT)calculations.Theoretical results demonstrate that Mn doping effectively enhances reactivity by reducing the oxygen vacancy formation energy(E_(vac))from 2.33 to 0.87 eV.However,Mn doping introduces HV/EV Ms lattice distortions that deteriorate elastic properties,thereby reducing wear resistance,as evidenced by a 54.54%decrease in the hardness-to-Young's modulus ratio(H_(v)/E_(v))forα-Fe_(2)O_(3)and an 83.33%reduction for Fe_(3)O_(4).Furthermore,Mn doping also modifies magnetic properties.The maximum of saturation magnetization(M_(s))of Fe_(3)O_(4)reaches 121.02 emu/g at 33.33%Mn doping concentration.Finally,systematic evaluation identifies 33.33%as the optimal Mn doping concentration,achieving a balance in enhanced reactivity,superior magnetic performance,and retained elastic stability.展开更多
The precise tuning of magnetic nanoparticle size and magnetic domains,thereby shaping magnetic properties.However,the dynamic evolution mechanisms of magnetic domain configurations in relation to electromagnetic(EM)at...The precise tuning of magnetic nanoparticle size and magnetic domains,thereby shaping magnetic properties.However,the dynamic evolution mechanisms of magnetic domain configurations in relation to electromagnetic(EM)attenuation behavior remain poorly understood.To address this gap,a thermodynamically controlled periodic coordination strategy is proposed to achieve precise modulation of magnetic nanoparticle spacing.This approach unveils the evolution of magnetic domain configurations,progressing from individual to coupled and ultimately to crosslinked domain configurations.A unique magnetic coupling phenomenon surpasses the Snoek limit in low-frequency range,which is observed through micromagnetic simulation.The crosslinked magnetic configuration achieves effective low-frequency EM wave absorption at 3.68 GHz,encompassing nearly the entire C-band.This exceptional magnetic interaction significantly enhances radar camouflage and thermal insulation properties.Additionally,a robust gradient metamaterial design extends coverage across the full band(2–40 GHz),effectively mitigating the impact of EM pollution on human health and environment.This comprehensive study elucidates the evolution mechanisms of magnetic domain configurations,addresses gaps in dynamic magnetic modulation,and provides novel insights for the development of high-performance,low-frequency EM wave absorption materials.展开更多
Strong coupling among spontaneous structural symmetric breaking,magnetism,and metallicity in an intrinsic polar magnetic metal can give rise to novel physical phenomena and holds great promise for applications in spin...Strong coupling among spontaneous structural symmetric breaking,magnetism,and metallicity in an intrinsic polar magnetic metal can give rise to novel physical phenomena and holds great promise for applications in spintronics.Here,we elucidate the mechanism of magnetic polarity in the recently discovered polar metal Sr_(3)Co_(2)O_(7).Our first-principles calculations reveal that both the spontaneous polar displacements and the metallicity originate from charge disproportionation of Co ions.This is characterized by an inverted ligand-field splitting of the Co t_(2g) orbitals at one site,while the metallic behavior is preserved by the t_(2g) orbitals at both sites.Charge disproportionation,which originates from the on-site Hubbard U interaction,stabilizes the asymmetric phase.We thus propose that in related transition metal oxides,charge disproportionation within specific orbitals can concurrently drive metallicity and polarity,enabling strong coupling between these properties.More remarkably,this mechanism allows for the coexistence of magnetism,as evidenced in Sr_(3)Co_(2)O_(7).Our findings highlight a promising avenue for realizing polar magnetic metals and provide a new design principle for exploring multifunctional materials.展开更多
A cost-effective Fe-P-C nanocrystalline alloy(Fe_(85)P_9C_6)was developed via melt-spinning by eliminating expensive alloying elements and post-annealing steps.The microstructure consists of an amorphous matrix with u...A cost-effective Fe-P-C nanocrystalline alloy(Fe_(85)P_9C_6)was developed via melt-spinning by eliminating expensive alloying elements and post-annealing steps.The microstructure consists of an amorphous matrix with uniformly dispersed nanocrystalline clusters,featuring an average size of approximately 5 nm.This dual-phase structure remains thermally stable up to 569 K and results in excellent magnetic and mechanical performance,including a high saturation magnetic induction of 1.69 T,Vickers hardness of 621 HV,and outstanding bending ductility.Crystallization proceeds via the transformation of a metastable fcc-(Fe,P,C)phase intoα-Fe,Fe_(3)C,and Fe_(3)P,driven by internal stress arising from atomic size mismatch.Continuous heating and cooling transformation diagrams further reveal that this process can be precisely controlled to optimize phase evolution.The high Fe content and stress-relaxed nanocrystalline clusters contribute to enhanced in-plane magnetic anisotropy and rapid domain response.This simplified,annealing-free approach not only reduces material and processing costs but also provides a viable pathway for scalable fabrication of next-generation soft magnetic alloys with superior performance and manufacturability.展开更多
BACKGROUND Many conditions may affect left ventricular(LV)phenotypes which have been classified according to LV mass and geometry.There is limited data on the prognostic value of LV phenotypes classified by cardiac ma...BACKGROUND Many conditions may affect left ventricular(LV)phenotypes which have been classified according to LV mass and geometry.There is limited data on the prognostic value of LV phenotypes classified by cardiac magnetic resonance(CMR).This study aimed to determine the prognostic value of LV phenotypes in elderly and non-elderly patients with known or suspected coronary artery disease.METHODS This is a retrospective cohort study among patients who underwent stress or viability CMR.LV phenotypes were classified according to the LV mass index,the LV end-diastolic volume index and the LV mass/volume ratio,into normal,concentric remodeling,concentric hypertrophy,and eccentric hypertrophy.The primary outcome was a composite of death or heart failure.RESULTS A total of 3289 patients was studied.The average age was 68.0±12.7 years,52.2%of patients were women.Elderly were defined as age≥65 years accounting for 63.9%of the cohort.LV phenotypes were normal,concentric remodeling,concentric hypertrophy,and eccentric hypertrophy at 74.5%,5.8%,9.2%,and 10.5%,respectively.The median duration of follow-up was 41.4 months.The composite outcome of death or heart failure occurred in 7.3%of patients.The prognostic impact of LV phenotypes was more pronounced in the elderly,with eccentric hypertrophy showing the worst prognosis,followed by concentric hypertrophy and concentric remodeling with the adjusted hazard ratio(95%CI)of 2.37(1.72–3.25),1.53(1.12–2.08),and 1.14(0.76–1.71),respectively,compared to normal phenotype.Patients with eccentric hypertrophy also demonstrated abnormal global longitudinal LV strain,left atrial strain,and extracellular volume fraction.CONCLUSIONS LV phenotypes by CMR independently predict adverse clinical outcomes in elderly patients with known or suspected coronary artery disease.In non-elderly patients,the prognostic value of LV phenotypes was less evident.Assessment of LV phenotypes may be useful for risk stratification.展开更多
Natural polymers possess the qualities of abundant resources,low cost,as well as excellent biocompatibility and biodegradability,and are ideal materials for next-generation wearable and portable electronic devices.To ...Natural polymers possess the qualities of abundant resources,low cost,as well as excellent biocompatibility and biodegradability,and are ideal materials for next-generation wearable and portable electronic devices.To further augment the application scope of natural polymer materials,integrating them with functional materials represents a promising approach that is of great value for the sustainable development of triboelectric nanogenerators.Here,we successfully synthesized starch-[CsPbBr_(3)-KBr]-Fe_(3)O_(4)composite films through the combination of natural polymer materials with magnetic and fluorescent components.It is capable of achieving reversible hydrochromic conversion by exposing or removing water.The combination of fluorescent CsPbBr_(3)-KBr,magnetic Fe_(3)O_(4),and waterproof starch-[CsPbBr_(3)-KBr]-Fe_(3)O_(4)-Polydimethylsiloxane leads to the realization of fluorescence and magnetic composite anti-counterfeiting.This composite anti-counterfeiting technology presents a novel and highly effective approach for ensuring the authenticity and security of various types of information.In addition,the Composite film based triboelectric nanogenerator has been assembled,which has a stable output with a short circuit current and open-circuit voltage of 15.1μA and 170.1 V,respectively.The triboelectric nanogenerator can light 204 red LED lights at the same time,and the electrical output is not reduced even after 4200 mechanical cycles.Furthermore,based on the triboelectric nanogenerator,we have successfully demonstrated a self-powered sensor that can monitor human movement signals in real time.The sensor has shown broad application prospects in the field of health monitoring and motion analysis.展开更多
基金National Natural Science Foundation of China(52171191,52371198)Project of Constructing National Independent Innovation Demonstration Zones(XM2024XTGXQ05)。
文摘Soft magnetic alloys are extensively used in various power electronic devices due to their advantageous properties,including high saturation magnetic induction,low coercivity,and high permeability.In certain applications,complex-shaped components are increasingly required for performance enhancement.Additive manufacturing technique,particularly selective laser melting(SLM),has emerged as an effective method for fabricating such complex-shaped soft magnetic components.SLM,a laserbased additive manufacturing technique,employs high-power-density lasers to melt and fuse metal powders within a powder bed selectively.This approach enables rapid prototyping,precise geometrical control,and the integration of multi-material designs.This review highlights recent advancements in the application of SLM technique for the production of soft magnetic alloys,focusing on Fe-Si,Fe-Ni,Fe-Co,and amorphous alloy systems.Moreover,it explores the implementation of SLM in manufacturing processes and evaluates both the opportunities and challenges associated with SLM-based production of soft magnetic alloys.
基金supported by the National KeyR&D Program of China(Grant No.2024YFB3817400)the National Natural Science Foundation of China(Grants No.12274276 and No.U24A6002)+1 种基金the Natural Science Foundation of Shanxi Province(China)(Grant No.202403021223008)Supported by Scientific and Technology Innovation Programs of Higher Education Institutions in Shanxi(Grant No.2024Q017 and No.2025L043).
文摘Layered transition-metal compounds(LTMCs)feature stacked architectures,strong magnetic anisotropy,and tunable magnetic order,making them promising material platforms for low-power spintronic technologies and for enabling topological functionalities in the post-Moore era.Here we review recent progress on two-dimensional(2D)magnetism in LTMCs,emphasizing material taxonomy,intrinsic magnetic properties,and external-field controls.This review first presents a classification of LTMCs by crystal structure and chemistry—binary halides,chalcogenides,and ternary families(e.g.,MPX_(3),M_(m)X_(n)Te_(k),MnBi_(2)Te_(4))—followed by a summary of their coupling mechanisms,ordering temperatures,and dimensional effects.It then analyzes the modulation of exchange interactions,magnetic anisotropy,and topological states by electric-field gating,strain engineering,and ion intercalation,with representative experimental demonstrations.Notable advances include room-temperature ferromagnetic metals and semiconductors,observation of the quantum anomalous Hall effect(QAHE)in MnBi2Te4,and synergistic control of magnetic-topological states under multiple external stimuli.Persistent challenges involve the limited availability of intrinsic 2D magnetic semiconductors with high Curie temperatures(Tc),incomplete understanding of the microscopic couplings at interfaces and under quantum confinement,and device-level stability.We conclude by outlining opportunities that lie in the integration of multiscale characterization,first-principles theory,and cross-scale fabrication to precisely co-engineer magnetism,topology,and electronic structure,thereby advancing LTMCs toward spintronic and topological-quantum applications.
文摘In this study,a multifunctional aptamer-conjugated magnetic covalent organic framework(COF)-CuO/Au nanozyme(MCOF-CuO/Au@apt)was developed as a“three-in-one”platform for dual-signal colorimetric and fluorescent detection of Vibrio parahaemolyticus.The nanozyme integrated magnetic separation,peroxidase-like catalytic activity,and specific target recognition through an aptamer-based strategy.Upon binding to V.parahaemolyticus,the catalytic oxidation of tetra-aminophenylethylene(TPE-4A)by the nanozyme was selectively inhibited,resulting in distinct colorimetric and fluorescent signals that significantly enhanced the detection accuracy and reliability.The proposed method exhibited high sensitivity,with limits of detection(LOD)of 21 and 7 CFU/mL for the colorimetric and fluorescent assays,respectively.The performance of this method was validated using real seafood samples,including Penaeus vannamei,Mytilus coruscus,and Crassostrea gigas,which showed high recovery rates(101.11%-107.30%)and excellent reproducibility.The system also demonstrated strong specificity and accuracy under various conditions,confirming its robustness and practical applicability.Collectively,this innovative platform presents a promising solution for the rapid,versatile,and sensitive detection of V.parahaemolyticus in seafood,with considerable potential to advance food safety diagnosis and on-site monitoring.
文摘Dissimilar AZ31B magnesium alloy and DC56D steel were welded via AA1060 aluminum alloy by magnetic pulse welding.The effects of primary and secondary welding processes on the welded interface were comparatively investigated.Macroscopic morphology,microstructure,and interfacial structure of the joints were analyzed using scanning electron microscope,energy dispersive spectrometer,and X-ray diffractometer(XRD).The results show that magnetic pulse welding of dissimilar Mg/Fe metals is achieved using an Al interlayer,which acts as a bridge for deformation and diffusion.Specifically,the AZ31B/AA1060 interface exhibits a typical wavy morphology,and a transition zone exists at the joint interface,which may result in an extremely complex microstructure.The microstructure of this transition zone differs from that of AZ31B magnesium and 1060 Al alloys,and it is identified as brittle intermetallic compounds(IMCs)Al_(3)Mg_(2) and Al_(12)Mg_(17).The transition zone is mainly distributed on the Al side,with the maximum thickness of Al-side transition layer reaching approximately 13.53μm.Incomplete melting layers with varying thicknesses are observed at the primary weld interface,while micron-sized hole defects appear in the transition zone of the secondary weld interface.The AA1060/DC56D interface is mainly straight,with only a small number of discontinuous transition zones distributed intermittently along the interface.These transition zones are characterized by the presence of the brittle IMC FeAl_(3),with a maximum thickness of about 4μm.
基金supported by the National Natural Science Foundation of China(Grant Nos.12488201,12274390,12304035,and 51627901)the Anhui Initiative in Quantum Information Technologies(Grant No.AHY160000)+3 种基金the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302802)the National Key R&D Program of the MOST of China(Grant No.2022YFA1602600)the Basic Research Program of the Chinese Academy of Sciences Based on Major Scientific Infrastructures(Grant No.JZHKYPT-2021-08)the National Key R&D Program of China(Grant No.2023YFA1607701)。
文摘Chiral magnets have attracted considerable attention due to their intricate magnetic properties,among which B20compounds constitute a quintessential class that has gained significant focus,particularly in the study of skyrmions.MnGe,as a member of the B20 family,exhibits a more complex magnetic structure compared with other materials with similar crystal structures.In this work,we successfully synthesized high-quality MnGe thin films and characterized their magnetoresistance,M-H curves,magneto-Seebeck effect,and magnetic force microscopy(MFM)images,all of which demonstrate pronounced magnetic anisotropy.Notably,the Seebeck coefficient exhibits a plateau at low magnetic fields when the magnetic field is applied in the film plane,indicating a field region in which the magnetic structure remains stable.MFM imaging further reveals magnetic transitions within the MnGe films when the magnetic field is oriented along the film plane.These findings are crucial for advancing our understanding of the magnetic ground state of MnGe and the evolution of its magnetic structure under an applied external magnetic field.
文摘T he residual stray magnetic fields present in ferromagnetic casting slabs were investigated in this work,which result from the magnetic fields generated during the steel casting process.Existing optical detection methods face challenges owing to surface oxide scales,and conventional high-precision magnetic sensors are ineffective at high temperatures.To overcome these limitations,a small coil sensor was employed to measure the residual magnetism strength in oscillation traces,using metal magnetic memory and electromagnetic induction methods,which can carry out detection without an external excitation source.Using this technology,the proposed scheme successfully detects defects at high tempe-ratures(up to 670℃)without a cooling device.The key findings include the ability to detect both surface and near-surface defects,such as cracks and oscillation marks,with an enhanced signal-to-noise ratio(SNR)of 7.2 dB after signal processing.The method’s practicality was validated in a steel mill environment,where testing on casting slabs effectively detected defects,providing a foundation for improving industrial quality control.The proposed detection scheme offers a significant advancement in nondestructive testing(NDT)for high-temperature applications,contributing to more efficient and accurate monitoring of ferromagnetic material integrity.
文摘Under hydrothermal and solvothermal conditions,two novel cobalt-based complexes,{[Co_(2)(CIA)(OH)(1,4-dtb)]·3.2H_(2)O}n(HU23)and{[Co_(2)(CIA)(OH)(1,4-dib)]·3.5H2O·DMF}n(HU24),were successfully constructed by coordinatively assembling the semi-rigid multidentate ligand 5-(1-carboxyethoxy)isophthalic acid(H₃CIA)with the Nheterocyclic ligands 1,4-di(4H-1,2,4-triazol-4-yl)benzene(1,4-dtb)and 1,4-di(1H-imidazol-1-yl)benzene(1,4-dib),respectively,around Co^(2+)ions.Single-crystal X-ray diffraction analysis revealed that in both complexes HU23 and HU24,the CIA^(3-)anions adopt aκ^(7)-coordination mode,bridging six Co^(2+)ions via their five carboxylate oxygen atoms and one ether oxygen atom.This linkage forms tetranuclear[Co4(μ3-OH)2]^(6+)units.These Co-oxo cluster units were interconnected by CIA^(3-)anions to assemble into 2D kgd-type structures featuring a 3,6-connected topology.The 2D layers were further connected by 1,4-dtb and 1,4-dib,resulting in 3D pillar-layered frameworks for HU23 and HU24.Notably,despite the similar configurations of 1,4-dtb and 1,4-dib,differences in their coordination spatial orientations lead to topological divergence in the 3D frameworks of HU23 and HU24.Topological analysis indicates that the frameworks of HU23 and HU24 can be simplified into a 3,10-connected net(point symbol:(4^(10).6^(3).8^(2))(4^(3))_(2))and a 3,8-connected tfz-d net(point symbol:(4^(3))_(2)((4^(6).6^(18).8^(4)))),respectively.This structural differentiation confirms the precise regulatory role of ligands on the topology of metal-organic frameworks.Moreover,the ultraviolet-visible absorption spectra confirmed that HU23 and HU24 have strong absorption capabilities for ultraviolet and visible light.According to the Kubelka-Munk method,their bandwidths were 2.15 and 2.08 eV,respectively,which are consistent with those of typical semiconductor materials.Variable-temperature magnetic susceptibility measurements(2-300 K)revealed significant antiferromagnetic coupling in both complexes,with their effective magnetic moments decreasing markedly as the temperature lowered.CCDC:2457554,HU23;2457553,HU24.
基金supported in part by the National Natural Science Foundation of China under grant 52175556the Macao Science and Technology Development Fund under grant 0004/2022/AKP,0102/2022/A2,and 0078/2023/RIB3+1 种基金the Research Committee of the University of Macao under grants MYRG2022-00068-FST and MYRG-CRG202200004-FST-ICIthe Guangdong Basic and Applied Basic Research Foundation under grant 2023A1515011178。
文摘In recent years,the rising incidence of gastrointestinal(GI)cancer has triggered an urgent need for effective early intervention strategies.Traditional endoscopic techniques often cause patient discomfort,and it is difficult to navigate deep regions of complex organ structures.This work proposes a kind of bio-inspired magnetic soft robot(BMSR)to address these challenges.The design of the BMSRs is inspired by the rolling motion of the golden wheel spider.Two six-degree-of-freedom(6-DOF)robotic arms are used,where one arm is responsible for real-time manipulation of the BMSRs,and the other is dedicated to monitoring their status.Under the actuation of an external rotating magnetic field,the BMSRs can flexibly climb on inclined surfaces at any angle,involving the inverted surface.Through the powerful output force,the BMSRs can overcome the mobility barrier induced by different human organs,including mucus,folds,and height differences of up to 8 cm.Such an exceptional mobility enables the BMSRs to deliver drugs in the targeted complex GI environment.Moreover,in combination with an endoscope,it provides real-time visual feedback for precise navigation.In vitro animal experiments validate the feasibility of BMSRs,paving a way for their usage in minimally invasive GI treatment.This work advances the potential applications of magnetic soft robots in the biomedical field.
基金supported by the Singapore Ministry of Education through MOE Tier 2 grant(MOE-T2EP10223-0006)the Australia Research Council(DP190100150,DE250100232)+2 种基金Singapore-International Synchrotron Access Programme(SG-SAP)the funding support from the RIE 2025 Industry Alignment FundIndustry Collaboration Projects(IAF-ICP)(Award I2301E0023),administered by A*STARsupported by Nanofilm Technologies International Limited。
文摘The spin-sensitive nature of redox reactions in energy conversion systems,such as the oxygen evolution reaction(OER),has attracted increasing attention due to its potential for enhancing catalytic efficiency.Magnetic fields(MFs)have been proposed to enhance OER performance by influencing the spin states of oxygen intermediates.However,prior study has predominantly focused on MF effects mediated by the intrinsic magnetic properties of electrocatalysts or magnetohydrodynamics.In this work,we report a universal enhancement in OER activity,achieving over 150% increase in current density under a200 mT MF across diamagnetic,paramagnetic and magnetic electrocatalysts in 1 M KOH.Through systematic investigation of MF orientation and strength,pH,applied potentials,and the use of benzoquinone radical scavenger,we demonstrate that MF-driven performance improvements arise from direct modulation of oxygen radical spin states.Specifically,MFs promote the formation of spin-triplet oxygen intermediates(↑O–O↑),a critical step for O–O bond formation,independent of the catalyst's intrinsic magnetism.However,the local magnetic environment near the catalyst surface,governed by its magnetic properties,indirectly influences radical spin dynamics by alternating the effective field experienced by intermediates.These findings redefine the role of spin manipulation in electrocatalysis,advancing understanding of MF-driven spin effects in redox reactions.
文摘The Circular Electron Positron Collider(CEPC)proposed in China is a dual-ring collider with electron and positron beams in the energy range of 45.5–180 GeV.The main dipole in the CEPC collider is a dual-aperture dipole with a shared coil between the two apertures,forming an I-shaped structure that can reduce power consumption by 50%.Because of its long length and low field strength,the development of this dual-aperture magnet faces challenges regarding its mechanical design,field measurement accuracy,and field performance.Numerical simulations were performed to better understand the Earth's field and the effect of different BH curves on field performance.The field results of the prototype are presented herein,and the field quality satisfies the requirements.The remanent field accounts for 2%of the integral field at 140 Gs,and the hysteresis effect caused an increase in field strength of approximately 0.075%after a standardization cycle of the trim coils.Research on this prototype can provide useful insights for understanding low-field dipole magnets.
基金supported by the CAS Pioneer Hundred Talents Program and Second Tibetan Plateau Scientific Expedition Research Program(2019QZKK0708)as well as the Basic Research Program of Qinghai Province:Lithospheric Geomagnetic Field of the Qinghai-Tibet Plateau and the Relationship with Strong Earthquakes(2021-ZJ-969Q).
文摘The National Geophysical Data Center(NGDC)of the United States has collected aeromagnetic data for input into a series of geomagnetic models to improve model resolution;however,in the Tibetan Plateau region,ground-based observations remain insufficient to clearly reflect the characteristics of the region’s lithospheric magnetism.In this study,we evaluate the lithospheric magnetism of the Tibetan Plateau by using a 3D surface spline model based on observations from>200 newly constructed repeat stations(portable stations)to determine the spatial distribution of plateau geomagnetism,as well as its correlation with the tectonic features of the region.We analyze the relationships between M≥5 earthquakes and lithospheric magnetic field variations on the Tibetan Plateau and identify regions susceptible to strong earthquakes.We compare the geomagnetic results with those from an enhanced magnetic model(EMM2015)developed by the NGDC and provide insights into improving lithospheric magnetic field calculations in the Tibetan Plateau region.Further research reveals that these magnetic anomalies exhibit distinct differences from the magnetic-seismic correlation mechanisms observed in other tectonic settings;here,they are governed primarily by the combined effects of compressional magnetism,thermal magnetism,and deep thermal stress.This study provides new evidence of geomagnetic anomalies on the Tibetan Plateau,interprets them physically,and demonstrates their potential for identifying seismic hazard zones on the Plateau.
基金supported by the Beijing Natural Science Foundation(Grant No.Z230006)the National Key Research and Development Program of China(Grant No.2022YFA1204000)the National Natural Science Foundation of China(Grant Nos.12274405 and 12393831)。
文摘We report the development of the[Pt_(0.75)Ti_(0.25)/Co-Ni multilayer/Ta]_n superlattice with strong spin-orbit torque,large perpendicular magnetic anisotropy,and remarkably low switching current density.We demonstrate that the efficiency of the spin-orbit torque increases nearly linearly with the repetition number n,which is in excellent agreement with the spin Hall effect of the Pt_(0.75)Ti_(0.25)being essentially the only source of the observed spin-orbit torque.The perpendicular magnetic anisotropy field is also substantially enhanced by more than a factor of 2 as n increases from 1 to6.The[Pt_(0.75)Ti_(0.25)/Co-Ni multilayers/Ta]_n superlattice additionally exhibits deterministic,low-current-density magnetization switching despite the very large total layer thicknesses.The unique combination of strong spin-orbit torque,robust perpendicular magnetic anisotropy,low-current-density switching,and excellent high thermal stability makes the[Pt_(0.75)Ti_(0.25)/Co-Ni multilayer/Ta]_n superlattice a highly compelling material candidate for ultrafast,energy-efficient,and long-data-retention spintronic technologies.
基金Project supported by the National Key Research and Decelopment Program of China(Grant No.2021YFB3500302)the National Natural Science Foundation of China(Grant Nos.U22A20116 and 52371200)the Innovation Capability Improvement Project of Hebei Province,China(Grant No.22567605H)。
文摘Large magnetic entropy change(△S_(M))can realize a prominent heat transformation under the magnetic field and directly strengthen the efficacy of the magnetocaloric effect,which provides a pioneering environmentally friendly solidstate strategy to improve refrigeration capacities and efficiencies.The second-order magnetic transition(SOMT)materials have broader△S_(M) peaks without thermal hysteresis,making them highly attractive in magnetic refrigeration,especially in the room temperature range.Here,we report a significant enhancement of△S_(M) at room temperature in single-crystal Mn_(5)Ge_(3).In this SOMT system,we realize a 60%improvement of-△S_(M)^(max) from 3.5 J/kg·K to 5.6 J/kg·K at T=300 K.This considerable enhancement of△S_(M) is achieved by intentionally introducing strain energy through high-pressure constrained deformation.Both experimental results and Monte Carlo simulations demonstrate that the enhancement of△S_(M) originates from the microscopic strain and lattice deformation induced by strain energy after deformation.This strain energy will reconstruct the energy landscape of this ferromagnetic system and enhance magnetization,resulting in a giant intensity of magnetocaloric responses.Our findings provide an approach to increase magnetic entropy change and may give fresh ideas for exploring advanced magnetocaloric materials.
基金supported by the “Climbing Plan” of Harbin Normal University (No.XKB202301)National Natural Science Foundation of China (Nos.21871065 and 22071038)。
文摘Magnetic field-driven spin polarization modulation has emerged as an effective way to boost the electrocatalytic oxygen evolution reaction(OER).However,the correlation among catalyst structure,magnetic property,and magnetic field enhanced-electrochemical activity remains to be fully elucidated.Herein,single-domain CoFe_(2)O_(4) catalysts with tunable oxygen vacancies(CFO-V_(O)) were synthesized to probe how V_(O) mediates magnetism and OER activity under magnetic field.The introduction of V_(O) can simultaneously modulate saturation magnetization(M_(s)) and coercivity(H_(c)),where the increased M_(s) dominates the magnetic field-enhanced OER activity.Under a 14,000 G magnetic field,the optimized CFO-V_(O) exhibits up to 16.1 % reduction in overpotential and 365 % enhancement in magnetocurrent(MC).Electrochemical analyses and post-OER characterization reveal that the magnetic field synergistically improves OER kinetics through lattice distortion induction,magnetohydrodynamic effect,and spin charge transfer effect.Importantly,the magnetic field promotes additional Co^(3+) generation to compensate for charge imbalance caused by V_(O) filling,maintaining dynamic equilibrium of V_(O) and effective reactant adsorption-conversion processes.This work unveils the synergistic mechanism of V_(O) and magnetic parameters for enhancing OER performance under the magnetic field,providing new insights into the design of high-efficiency spinregulated OER catalysts.
基金Supported by National Natural Science Foundation of China(50976032,51776070)。
文摘Oxygen carriers play a fundamental role in chemical looping combustion(CLC).Iron-based carriers have been extensively investigated owing to their abundance and environmentally friendly.However,the reactivity and separability of iron-based carriers require further enhancement.This study investigates the effect of the concentration of Mn doping on reactivity,elastic properties and magnetic properties based on density functional theory(DFT)calculations.Theoretical results demonstrate that Mn doping effectively enhances reactivity by reducing the oxygen vacancy formation energy(E_(vac))from 2.33 to 0.87 eV.However,Mn doping introduces HV/EV Ms lattice distortions that deteriorate elastic properties,thereby reducing wear resistance,as evidenced by a 54.54%decrease in the hardness-to-Young's modulus ratio(H_(v)/E_(v))forα-Fe_(2)O_(3)and an 83.33%reduction for Fe_(3)O_(4).Furthermore,Mn doping also modifies magnetic properties.The maximum of saturation magnetization(M_(s))of Fe_(3)O_(4)reaches 121.02 emu/g at 33.33%Mn doping concentration.Finally,systematic evaluation identifies 33.33%as the optimal Mn doping concentration,achieving a balance in enhanced reactivity,superior magnetic performance,and retained elastic stability.
基金supported by the National Natural Science Foundation of China(22265021,52231007,and 12327804)the Aeronautical Science Foundation of China(2020Z056056003)Jiangxi Provincial Natural Science Foundation(20232BAB212004).
文摘The precise tuning of magnetic nanoparticle size and magnetic domains,thereby shaping magnetic properties.However,the dynamic evolution mechanisms of magnetic domain configurations in relation to electromagnetic(EM)attenuation behavior remain poorly understood.To address this gap,a thermodynamically controlled periodic coordination strategy is proposed to achieve precise modulation of magnetic nanoparticle spacing.This approach unveils the evolution of magnetic domain configurations,progressing from individual to coupled and ultimately to crosslinked domain configurations.A unique magnetic coupling phenomenon surpasses the Snoek limit in low-frequency range,which is observed through micromagnetic simulation.The crosslinked magnetic configuration achieves effective low-frequency EM wave absorption at 3.68 GHz,encompassing nearly the entire C-band.This exceptional magnetic interaction significantly enhances radar camouflage and thermal insulation properties.Additionally,a robust gradient metamaterial design extends coverage across the full band(2–40 GHz),effectively mitigating the impact of EM pollution on human health and environment.This comprehensive study elucidates the evolution mechanisms of magnetic domain configurations,addresses gaps in dynamic magnetic modulation,and provides novel insights for the development of high-performance,low-frequency EM wave absorption materials.
基金supported by the National Natural Science Foundation of China (Grant No.12274309 for H.-F.H.and J.-X.Y.)NERSC award (Grant No.BES-ERCAP0037158)。
文摘Strong coupling among spontaneous structural symmetric breaking,magnetism,and metallicity in an intrinsic polar magnetic metal can give rise to novel physical phenomena and holds great promise for applications in spintronics.Here,we elucidate the mechanism of magnetic polarity in the recently discovered polar metal Sr_(3)Co_(2)O_(7).Our first-principles calculations reveal that both the spontaneous polar displacements and the metallicity originate from charge disproportionation of Co ions.This is characterized by an inverted ligand-field splitting of the Co t_(2g) orbitals at one site,while the metallic behavior is preserved by the t_(2g) orbitals at both sites.Charge disproportionation,which originates from the on-site Hubbard U interaction,stabilizes the asymmetric phase.We thus propose that in related transition metal oxides,charge disproportionation within specific orbitals can concurrently drive metallicity and polarity,enabling strong coupling between these properties.More remarkably,this mechanism allows for the coexistence of magnetism,as evidenced in Sr_(3)Co_(2)O_(7).Our findings highlight a promising avenue for realizing polar magnetic metals and provide a new design principle for exploring multifunctional materials.
基金the support received from the National Natural Science Foundation of China(No.52202213)the Shandong Province Youth Fund(Nos.ZR2024QE439,ZR2024QE532)+2 种基金the Scientific Research Fund of Dezhou University(No.30103540)the China Postdoctoral Science Foundation(No.2023M730905)the Science Research Project of the Hebei Education Department(No.QN2024031)。
文摘A cost-effective Fe-P-C nanocrystalline alloy(Fe_(85)P_9C_6)was developed via melt-spinning by eliminating expensive alloying elements and post-annealing steps.The microstructure consists of an amorphous matrix with uniformly dispersed nanocrystalline clusters,featuring an average size of approximately 5 nm.This dual-phase structure remains thermally stable up to 569 K and results in excellent magnetic and mechanical performance,including a high saturation magnetic induction of 1.69 T,Vickers hardness of 621 HV,and outstanding bending ductility.Crystallization proceeds via the transformation of a metastable fcc-(Fe,P,C)phase intoα-Fe,Fe_(3)C,and Fe_(3)P,driven by internal stress arising from atomic size mismatch.Continuous heating and cooling transformation diagrams further reveal that this process can be precisely controlled to optimize phase evolution.The high Fe content and stress-relaxed nanocrystalline clusters contribute to enhanced in-plane magnetic anisotropy and rapid domain response.This simplified,annealing-free approach not only reduces material and processing costs but also provides a viable pathway for scalable fabrication of next-generation soft magnetic alloys with superior performance and manufacturability.
文摘BACKGROUND Many conditions may affect left ventricular(LV)phenotypes which have been classified according to LV mass and geometry.There is limited data on the prognostic value of LV phenotypes classified by cardiac magnetic resonance(CMR).This study aimed to determine the prognostic value of LV phenotypes in elderly and non-elderly patients with known or suspected coronary artery disease.METHODS This is a retrospective cohort study among patients who underwent stress or viability CMR.LV phenotypes were classified according to the LV mass index,the LV end-diastolic volume index and the LV mass/volume ratio,into normal,concentric remodeling,concentric hypertrophy,and eccentric hypertrophy.The primary outcome was a composite of death or heart failure.RESULTS A total of 3289 patients was studied.The average age was 68.0±12.7 years,52.2%of patients were women.Elderly were defined as age≥65 years accounting for 63.9%of the cohort.LV phenotypes were normal,concentric remodeling,concentric hypertrophy,and eccentric hypertrophy at 74.5%,5.8%,9.2%,and 10.5%,respectively.The median duration of follow-up was 41.4 months.The composite outcome of death or heart failure occurred in 7.3%of patients.The prognostic impact of LV phenotypes was more pronounced in the elderly,with eccentric hypertrophy showing the worst prognosis,followed by concentric hypertrophy and concentric remodeling with the adjusted hazard ratio(95%CI)of 2.37(1.72–3.25),1.53(1.12–2.08),and 1.14(0.76–1.71),respectively,compared to normal phenotype.Patients with eccentric hypertrophy also demonstrated abnormal global longitudinal LV strain,left atrial strain,and extracellular volume fraction.CONCLUSIONS LV phenotypes by CMR independently predict adverse clinical outcomes in elderly patients with known or suspected coronary artery disease.In non-elderly patients,the prognostic value of LV phenotypes was less evident.Assessment of LV phenotypes may be useful for risk stratification.
基金supported by the Key Research Program of Frontier Sciences,CAS,China(ZDBS-LY-DQC025)the Basic Scientific Research Project of the National Institute of Metrology,China(AKYZZ2449,AKYZZ2546).
文摘Natural polymers possess the qualities of abundant resources,low cost,as well as excellent biocompatibility and biodegradability,and are ideal materials for next-generation wearable and portable electronic devices.To further augment the application scope of natural polymer materials,integrating them with functional materials represents a promising approach that is of great value for the sustainable development of triboelectric nanogenerators.Here,we successfully synthesized starch-[CsPbBr_(3)-KBr]-Fe_(3)O_(4)composite films through the combination of natural polymer materials with magnetic and fluorescent components.It is capable of achieving reversible hydrochromic conversion by exposing or removing water.The combination of fluorescent CsPbBr_(3)-KBr,magnetic Fe_(3)O_(4),and waterproof starch-[CsPbBr_(3)-KBr]-Fe_(3)O_(4)-Polydimethylsiloxane leads to the realization of fluorescence and magnetic composite anti-counterfeiting.This composite anti-counterfeiting technology presents a novel and highly effective approach for ensuring the authenticity and security of various types of information.In addition,the Composite film based triboelectric nanogenerator has been assembled,which has a stable output with a short circuit current and open-circuit voltage of 15.1μA and 170.1 V,respectively.The triboelectric nanogenerator can light 204 red LED lights at the same time,and the electrical output is not reduced even after 4200 mechanical cycles.Furthermore,based on the triboelectric nanogenerator,we have successfully demonstrated a self-powered sensor that can monitor human movement signals in real time.The sensor has shown broad application prospects in the field of health monitoring and motion analysis.
