In the context of the global energy low-carbon transition,phase change energy storage technology becomes a key technology to solve the problem of intermittent renewable energy.Oriented phase change composites(OCPCMs)r...In the context of the global energy low-carbon transition,phase change energy storage technology becomes a key technology to solve the problem of intermittent renewable energy.Oriented phase change composites(OCPCMs)receive widespread attention in practical energy storage applications due to their unique oriented thermally conductive structure,which achieves significant thermal conductivity enhancement in specific directions while retaining the high energy storage capacity of the phase change components.This review systematically summarizes the overall analysis of OCPCMs from synthesis and preparation to application scenarios in recent years.Herein,we introduce the analysis of the heat transfer mechanism of the materials and explore the advantages of the oriented structure in OCPCMs in the heat transfer behavior from a bionic perspective.We then focus on summarizing and generalizing the methods for preparing OCPCMs,giving suggestions for suitable methods according to different scenarios.Besides,we discuss the application of finite element simulation methods to the monitoring of the thermal management behavior of OCPCMs,and look into the potential future application areas of such materials.Finally,it is hoped that this review will provide guidance for the academic community in developing high-performance OCPCMs.展开更多
The absence of large-size gallium nitride(GaN) substrates with low dislocation density remains a primary bottleneck for advancing GaN-based devices. Here, we demonstrate the achievement of 8-inch freestanding GaN subs...The absence of large-size gallium nitride(GaN) substrates with low dislocation density remains a primary bottleneck for advancing GaN-based devices. Here, we demonstrate the achievement of 8-inch freestanding GaN substrates grown by hydride vapor phase epitaxy. Critical to this achievement is the improvement in gas-flow uniformity, which ensures exceptional thickness homogeneity and enables the crack-free growth of GaN. After laser lift-off(LLO) separation, the freestanding GaN substrate exhibits superior crystal quality, evidenced by full width at half maximum values of 68 and 54 arcsec for X-ray diffraction rocking curves of(002) and(102) planes, alongside a low dislocation density of 1.6 × 10^(6) cm^(-2). This approach establishes a robust pathway for the production of large-size GaN substrates, which are essential for advancing next-generation power electronics and high-efficiency photonics.展开更多
Cation disordering is a common issue in Ni-rich cathodes that significantly degrades cycle life and compromises safety.The cubic rock-salt phase formation and the slow oxidation kinetics of Ni^(2+)during solid-state s...Cation disordering is a common issue in Ni-rich cathodes that significantly degrades cycle life and compromises safety.The cubic rock-salt phase formation and the slow oxidation kinetics of Ni^(2+)during solid-state sintering are widely recognized as the principal causes of these structural defects.To solve this issue,a topotactic soft-chemical precursor engineering strategy is proposed for use in aqueous solution.By utilizing the layered structure of the precursor,this method allows for selective proton extraction and efficient Ni^(2+)oxidation,along with rapid Li+intercalation to form a layered lithiated intermediate.This intermediate crystallizes without further phase transitions during subsequent heat treatment,preventing structural defects caused by complex phase evolution and slow ion diffusion.The resulting cathode exhibits a long-range ordered layered structure and a uniform phase distribution,enabling efficient Li+insertion and extraction.Electrochemical tests reveal a high discharge capacity of 229.6 mAh g^(−1)and an initial coulombic efficiency of 95.77%at 0.1 C,greatly exceeding the performance of a conventionally synthesized cathode(210.3 mAh g^(−1),88.93%).Improved Li^(+)transport kinetics reduces phase-transition hysteresis and alleviates stress concentration,resulting in better cycling stability with a capacity retention of 85.3%after 300 cycles,compared to 61.5%for the conventional sample.This work presents a scalable and effective synthesis route for Ni-rich cathodes with reduced structural disorder and extended lifespan,providing valuable insights into how the regulation of intermediate phases influences electrochemical performance in high-performance Ni-rich cathodes.展开更多
Sodium-ion hybrid capacitors(SICs)offer inherent energy-power synergy but are constrained by mismatched kinetics and life spans between the anode and cathode materials.Two-dimensional MoS_(2)@C composites demonstrate ...Sodium-ion hybrid capacitors(SICs)offer inherent energy-power synergy but are constrained by mismatched kinetics and life spans between the anode and cathode materials.Two-dimensional MoS_(2)@C composites demonstrate excellent kinetics and structural stability,thanks to the built-in electric field of the carbon heterostructure and its adaptability to volume changes.Yet,the carbon shell imposes a physical barrier to interfacial Na^(+)diffusion,while deep discharge induces the formation of crystalline Na_(2)S,accompanied by severe volumetric expansion and sluggish reversibility—factors that accelerate capacity fading and structural degradation.To address these challenges,a trace-level Ni doping strategy is introduced,enabling precise modulation of the composite's interlayer structure,electronic configuration,and reaction pathway.Ni incorporation expands the MoS_(2) interlayer spacing,reconstructs short-range ordered nanocrystals within a hierarchically porous network,and promotes Na^(+)diffusion by weakening interlayer van der Waals forces.Orbital hybridization between Ni-3d and Mo-4d/S-3p states enhances electronic conductivity and reduces charge transfer resistance.Critically,Ni doping enhances electron transfer from Ni to sulfur,which weakens Na–S bonds and promotes the formation of amorphous Na_(2)S,thereby suppressing crystalline Na_(2)S and enabling a reversible MoS_(2)/Na_(2)S conversion mechanism for improved structural stability and cycling performance.As a result,the optimized MoS_(2)-Ni@C anode delivers a high reversible capacity of 334 mAh g^(-1)at 10 A g^(-1)with 68%retention after 10,000 cycles.When assembled into a SIC device(MoS_(2)-Ni@C//AC),it achieves an energy density of 135 Wh kg^(-1)at a power density of 60.8 kW kg^(-1)(based on anode mass),with 76%retention over 3,000 cycles.展开更多
Co-free Li-rich Li_(1.2)Ni_(0.2)Mn_(0.6)O_(2)(LR)cathode shows the highest working capacity that can be applied to high-energy density Li-ion batteries(LIBs).However,poor cycle stability and voltage decay caused by ph...Co-free Li-rich Li_(1.2)Ni_(0.2)Mn_(0.6)O_(2)(LR)cathode shows the highest working capacity that can be applied to high-energy density Li-ion batteries(LIBs).However,poor cycle stability and voltage decay caused by phase transition are always hindering its further development.Herein,a novel medium-entropy Li-rich Mn-based cathode material(LRMEF)was synthesized via a simple sol-gel method.The introduction of multivalent ions(Al^(3+)/Cu^(2+)doping at Mn sites and F−doping at O sites)effectively mitigates the Jahn-Teller distortion of Mn ions and suppresses oxygen release.High-angle annular dark-field scanning transmission electron microscopy(HAADF-STEM)images confirm that this synergistic doping strategy induces the in-situ formation of an approximately 3 nm-thick spinel surface layer,which significantly enhances structural stability and ion diffusion kinetics.Besides,a series of in-situ/ex-situ characterization methods and density functional theory(DFT)calculations have been carried out to fundamentally shed light on the optimized structure-activity relationship and reaction mechanism.As a result,the LR material with entropy regulation and anion doping exhibits excellent cycling stability(189.2 mAh g^(−1)at 1 C with 84%capacity retention after 300 cycles),rate performance(164.1 mAh g^(−1)at 5 C),and voltage retention(82.7%at 1 C after 300 cycles),demonstrating great application prospects in future high-energy-density LIBs.展开更多
The application of conventional manganese dioxide(MnO_(2))materials in sodium-ion supercapacitors(Na-SCs)is considerably limited by their low conductivity and structural instability.Biomimetic morphology engineering c...The application of conventional manganese dioxide(MnO_(2))materials in sodium-ion supercapacitors(Na-SCs)is considerably limited by their low conductivity and structural instability.Biomimetic morphology engineering can optimize the electrochemical performance of MnO_(2).Here,based on the metal-organic frameworks(MOFs)-derived method and electrochemical reconstruction,a coral-like MnO_(2)structure integrated with a functional nitrogen-doped carbon(NC)coating is designed for Na-SC application.The bioinspired coral-like structure captures numerous electrolyte ions and increases the Na+concentration on the electrode surface,which is beneficial for optimizing the Na+transport pathway and accelerating the electrode reaction kinetics.Moreover,the coral-like crosslinked structure effectively enhances the mechanical properties,enabling the maintenance of the structure of MnO_(2)-based electrodes during long-term operation.Furthermore,in/ex-situ characterizations are performed to elucidate the mechanism of lattice transformation during electrochemical phase reconstruction.Additionally,the theoretical calculation and simulation results reveal the ion/electron dynamics in the fabricated electrode.The prepared electrode demonstrates excellent capacitance storage ability(340.7 F g^(−1)at 0.5 A g^(−1))and cycling stability(85.1%capacitance retention after 10,000 cycles).The assembled hybrid device exhibits exceptional life-span(82.0%capacitance retention after 10,000 cycles)and exceptional energy density(36.5 Wh kg^(−1)).This study provides a reliable biomimetic morphology design strategy for MnO_(2)cathodes,paving the way for the fabrication of high-performance Na-SCs.展开更多
To address the challenge of balancing thermal management and thermal runaway mitigation,it is crucial to explore effective methods for enhancing the safety of lithium-ion battery systems.Herein,an innovative hydrated ...To address the challenge of balancing thermal management and thermal runaway mitigation,it is crucial to explore effective methods for enhancing the safety of lithium-ion battery systems.Herein,an innovative hydrated salt composite phase change material(HSCPCM)with dual phase transition temperature zones has been proposed.This HSCPCM,denoted as SDMA10,combines hydrophilic modified expanded graphite,an acrylic emulsion coating,and eutectic hydrated salts to achieve leakage prevention,enhanced thermal stability,cycling stability,and superior phase change behavior.Battery modules incorporating SDMA10 demonstrate significant thermal control capabilities.Specifically,the cylindrical battery modules with SDMA10 can maintain maximum operating temperatures below 55°C at 4 C discharge rate,while prismatic battery modules can keep maximum operating temperatures below 65°C at 2 C discharge rate.In extreme battery overheating conditions simulated using heating plates,SDMA10 effectively suppresses thermal propagation.Even when the central heating plate reaches 300°C,the maximum temperature at the module edge heating plates remains below 85°C.Further,compared to organic composite phase change materials(CPCMs),the battery module with SDMA10 can further reduce the peak thermal runaway temperature by 93°C and delay the thermal runaway trigger time by 689 s,thereby significantly decreasing heat diffusion.Therefore,the designed HSCPCM integrates excellent latent heat storage and thermochemical storage capabilities,providing high thermal energy storage density within the thermal management and thermal runaway threshold temperature range.This research will offer a promising pathway for improving the thermal safety performance of battery packs in electric vehicles and other energy storage systems.展开更多
The water-quenched(WQ)2195 Al−Li alloy was subjected to stretching at different temperatures,from room temperature(RT)to−196℃(CT),to investigate the effect of cryogenic deformation on the aging precipitation behavior...The water-quenched(WQ)2195 Al−Li alloy was subjected to stretching at different temperatures,from room temperature(RT)to−196℃(CT),to investigate the effect of cryogenic deformation on the aging precipitation behaviors and mechanical properties.The precipitation kinetics of the T1 phase and the microstructures in peak aging state were investigated through the differential scanning calorimetric(DSC)tests and electron microscopy observation.The results show that−196℃deformation produces a high dislocation density,which promotes the precipitation of the T1 phase and refines its sizes significantly.In addition,the grain boundary precipitates(GBPs)of−196℃-stretched samples are suppressed considerably due to the high dislocation density in the grain interiors,which increases the ductility.In comparison,the strength remains nearly constant.Thus,it is indicated that cryogenic forming has the potential to provide the shape and property control for the manufacture of critical components of aluminum alloys.展开更多
Conventional Tb^(3+)-doped phosphors typically suffer from concentration quenching once the doping level exceeds a critical threshold.Consequently,the development of Tb^(3+)phosphors with intrinsic resistance to conce...Conventional Tb^(3+)-doped phosphors typically suffer from concentration quenching once the doping level exceeds a critical threshold.Consequently,the development of Tb^(3+)phosphors with intrinsic resistance to concentration quenching has become a key research focus.In this work,we successfully synthesized KBi(MoO_(4))_(2):x Tb^(3+)(x=0-100 at%)(denoted as KBM:x Tb^(3+))phosphors via a high-temperature solid-state reaction.Remarkably,no concentration quenching was observed across the entire doping range.This anti-quenching behavior originates from the large Tb^(3+)-Tb^(3+)interionic distance(>5Å)inherent to the quasi-layered crystal structure,which effectively suppresses multipole-interaction-mediated energy migration.At full Tb^(3+)substitution(x=100 at%),the material undergoes a structural phase transition from the monoclinic KBM phase to the triclinicα-KTb(MoO_(4))_(2)(α-KTM)phase.Theα-KTM phosphor exhibits excellent thermal stability(activation energy=0.6129 eV)and a single-exponential decay profile,whereas KBM:x Tb^(3+)(x<100%)display double-exponential decay behaviors,attributed to dual energy transfer pathways.These findings provide new insights into the luminescence mechanisms of high-concentration rare-earth-doped systems and offer guidance for designing nextgeneration anti-quenching phosphors.展开更多
It is well known that aluminum and copper exhibit structural phase transformations in quasi-static and dynamic measurements,including shock wave loading.However,the dependence of phase transformations in a wide range ...It is well known that aluminum and copper exhibit structural phase transformations in quasi-static and dynamic measurements,including shock wave loading.However,the dependence of phase transformations in a wide range of crystallographic directions of shock loading has not been revealed.In this work,we calculated the shock Hugoniot for aluminum and copper in different crystallographic directions([100],[110],[111],[112],[102],[114],[123],[134],[221]and[401])of shock compression using molecular dynamics(MD)simulations.The results showed a high pressure(>160 GPa for Cu and>40 GPa for Al)of the FCC-to-BCC transition.In copper,different characteristics of the phase transition are observed depending on the loading direction with the[100]compression direction being the weakest.The FCC-to-BCC transition for copper is in the range of 150–220 GPa,which is consistent with the existing experimental data.Due to the high transition pressure,the BCC phase transition in copper competes with melting.In aluminum,the FCC-to-BCC transition is observed for all studied directions at pressures between 40 and 50 GPa far beyond the melting.In all considered cases we observe the coexistence of HCP and BCC phases during the FCC-to-BCC transition,which is consistent with the experimental data and atomistic calculations;this HCP phase forms in the course of accompanying plastic deformation with dislocation activity in the parent FCC phase.The plasticity incipience is also anisotropic in bothmetals,which is due to the difference in the projections of stress on the slip plane for different orientations of the FCC crystal.MD modeling results demonstrate a strong dependence of the FCC-to-BCC transition on the crystallographic direction,in which the material is loaded in the copper crystals.However,MD simulations data can only be obtained for specific points in the stereographic direction space;therefore,for more comprehensive understanding of the phase transition process,a feed-forward neural network was trained using MD modeling data.The trained machine learning model allowed us to construct continuous stereographic maps of phase transitions as a function of stress in the shock-compressed state of metal.Due to appearance and growth of multiple centers of new phase,the FCC-to-BCC transition leads to formation of a polycrystalline structure from the parent single crystal.展开更多
Optical phase transfer via fiber optics is the most effective method for optical frequency standard comparison on the scale below thousands of kilometers.However,the monotonic phase discrimination range of conventiona...Optical phase transfer via fiber optics is the most effective method for optical frequency standard comparison on the scale below thousands of kilometers.However,the monotonic phase discrimination range of conventional optical phase-locked loops is limited,and link delays restrict the control bandwidth,which makes it a challenge to achieve a continuously reliable optical link.This paper presents an event-timing-based phase detection method that overcomes the monotonic phase discrimination range limitation of conventional phase-locked loops through dual-edge timestamp recording,achieving an optical phase measurement resolution on the order of 10 attoseconds.With such a technique,we established a 7-segment-cascaded optical link over 1402km of commercial fiber while sharing dense wavelength division multiplexing(DWDM)channels with live telecom traffic.The system maintained continuous operation for 11.7 days without phase cycle slips despite encountering 15 km aerial fiber noise up to 21000 rad^(2)·Hz^(−1)·km^(−1)at 1 Hz.Relative instabilities of the link are 3.7×10^(−15)at 1 s and 3.9×10^(−20)at 100000 s.展开更多
In Chin.Phys.B 34114704(2025),Eq.(7)and the associated unit notation were incorrect.The correct ones are present here.Since Eq.(7)is an in-built expression in the simulation package,the correction is purely typographi...In Chin.Phys.B 34114704(2025),Eq.(7)and the associated unit notation were incorrect.The correct ones are present here.Since Eq.(7)is an in-built expression in the simulation package,the correction is purely typographical and does not affect the simulation procedure,numerical results,or the conclusions.展开更多
Light-energy-driven semiconductor catalysis offers attractive ways to address environmental and energy crises.TiO_(2) is the most promising catalyst for photocatalysis,but the lack of charge-carrier separation efficie...Light-energy-driven semiconductor catalysis offers attractive ways to address environmental and energy crises.TiO_(2) is the most promising catalyst for photocatalysis,but the lack of charge-carrier separation efficiency severely limits its catalytic performance.In this study,we carried out crystal phase engineering to prepare in situ Z-scheme hetero-phase homojunction of anatase-rutile and clarified the structure-performance relationship.The efficiency of sulfamerazine removal by hetero-phase homojunction TiO_(2) nanotube arrays in a single-compartment photocatalytic fuel cell system was improved by 1.93 times compared to conventional anatase TiO_(2) nanotube arrays and the degradation pathways were revealed by the Fukui function combined with HP-LCMS.The successful construction of Z-scheme hetero-phase homojunction was confirmed by Raman,X-ray diffraction(XRD),and electron spin resonance(ESR),which combined with density functional theory(DFT)calculations revealed the key role of crystal phase engineering in the construction of hetero-phase homojunction.This work provides a novel strategy for the scientific design of titanium dioxide photocatalysts.展开更多
Mechanoluminescent(ML)materials that emit light under mechanical stress are attracting growing attention for their potential in next-generation sensing,display,and energy-harvesting technologies[1].Among these,Mn/Cu-d...Mechanoluminescent(ML)materials that emit light under mechanical stress are attracting growing attention for their potential in next-generation sensing,display,and energy-harvesting technologies[1].Among these,Mn/Cu-doped zinc sulfide(ZnS)has emerged as a leading candidate due to its bright emission,low activation threshold,and remarkable self-recovery over thousands of cycles[2-5].展开更多
Beryllium-containing sludge(BCS)is a typical hazardous waste from Be smelting,which can cause serious harm to ecology and human health by releasing harmful Be if it is stored long-term in environment.Nonetheless,the o...Beryllium-containing sludge(BCS)is a typical hazardous waste from Be smelting,which can cause serious harm to ecology and human health by releasing harmful Be if it is stored long-term in environment.Nonetheless,the occurrence of Be in BCS is unclear,which seriously hinders the development of pollution control technologies.In order to enhance the understanding of BCS,the occurrence of Be and the microscale interactions with coexisting phases were investigated for the first time.It was found that CaSO_(4)·2H_(2)O and amorphous SiO_(2) are the primary phases of BCS.The simulated experiments of purified materials showed that Be interacted with CaSO_(4)·2H_(2)O and amorphous SiO_(2).Be can enter into the lattice of CaSO_(4)·2H_(2)O mainly as free Be2+.Amorphous SiO_(2) can adsorb Be2+particularly at a pH range of 3–5.The dissolution behavior experiment of BCS shows that about 52%of the Be is readily extracted under acidic conditions,which refers to the Be of independent occurrence.In contrast,the remaining 48%of Be can be extracted only after the CaSO_(4)·2H_(2)O has completely dissolved.Hence,CaSO_(4)·2H_(2)O is identified as the key occurrence phase which determines the highly efficient dissolution of Be.As a result,this study enhances the understanding of BCS and lays the foundation for the development of Be separation technologies.展开更多
Laser wakefield accelerators(LWFAs)offer acceleration gradients up to 1000 times higher than those of conventional radio-frequency accelerators,offering a pathway to significantly more compact and cost-effective accel...Laser wakefield accelerators(LWFAs)offer acceleration gradients up to 1000 times higher than those of conventional radio-frequency accelerators,offering a pathway to significantly more compact and cost-effective accelerator systems.This breakthrough opens up new possibilities for laboratory-scale light sources.All-optical inverse Compton scattering(AOCS)sources driven by LWFAs produce high-brightness,quasimonochromatic X rays with micrometer-scale source sizes,delivering the spatial coherence and resolution required for X-ray phase-contrast imaging(XPCI).These features position AOCS X-ray sources as promising tools for applications in biology,medicine,physics,and materials science.However,previous AOCS-based imaging studies have primarily focused on X-ray absorption imaging.In this work,we report successful experimental demonstrations of edge-enhanced in-line XPCI using energy-tunable,quasi-monochromatic AOCS X rays.With a spatial resolution of~20μm,our results clearly show the potential of high-resolution,AOCS-based XPCI applications.展开更多
[Background]High harmonic cavities are widely used in electron storage rings to lengthen thebunch,lower the bunch peak current,thereby reducing the IBS effect,enhancing the Touschek lifetime,as well asproviding Landau...[Background]High harmonic cavities are widely used in electron storage rings to lengthen thebunch,lower the bunch peak current,thereby reducing the IBS effect,enhancing the Touschek lifetime,as well asproviding Landau damping,which is particularly important for storage rings operating with ultra-low emittance or atlow beam energy.[Purpose]To further increase the bunch length without additional hardware costs,the phasemodulation in a dual-RF system is considered.[Methods]In this paper,turn-by-turn simulations incorporating randomsynchrotron radiation excitation are conducted,and a brief analysis is presented to explain the bunch lengtheningmechanism.[Results]Simulation results reveal that the peak current can be further reduced,thereby mitigating IBSeffects and enhancing the Touschek lifetime.Although the energy spread increases,which tends to reduce thebrightness of higher-harmonic radiation from the undulator,the brightness of the fundamental harmonic can,in fact,beimproved.展开更多
Active matter is a non-equilibrium condensed system consisting of self-propelled particles capable of converting stored or ambient energy into collective motion.Typical active matter systems include cytoskeleton biopo...Active matter is a non-equilibrium condensed system consisting of self-propelled particles capable of converting stored or ambient energy into collective motion.Typical active matter systems include cytoskeleton biopolymers,swimming bacteria,artificial swimmers,and animal herds.In contrast to wet active matter,dry active matter is an active system characterized by the absence of significant hydrodynamic interactions and conserved momentum.In dry active matter,the role of surrounding fluids is providing viscous friction at low Reynolds numbers and can be neglected at high Reynolds numbers.This review offers a comprehensive overview of recent experimental,computational,and theoretical advances in understanding phase transitions and critical phenomena in dry aligning active matter,including polar particles,self-propelled rods,active nematics,and their chiral counterparts.Various ways of determining phase transition points as well as non-equilibrium phenomena,such as collective motion,cluster formation,and creation and annihilation of topological defects are reviewed.展开更多
基金financially supported by the Fundamental Research Funds for the Central Universities(No.FRF-KST-25-001)the Beijing Natural Science Foundation(No.L253029)。
文摘In the context of the global energy low-carbon transition,phase change energy storage technology becomes a key technology to solve the problem of intermittent renewable energy.Oriented phase change composites(OCPCMs)receive widespread attention in practical energy storage applications due to their unique oriented thermally conductive structure,which achieves significant thermal conductivity enhancement in specific directions while retaining the high energy storage capacity of the phase change components.This review systematically summarizes the overall analysis of OCPCMs from synthesis and preparation to application scenarios in recent years.Herein,we introduce the analysis of the heat transfer mechanism of the materials and explore the advantages of the oriented structure in OCPCMs in the heat transfer behavior from a bionic perspective.We then focus on summarizing and generalizing the methods for preparing OCPCMs,giving suggestions for suitable methods according to different scenarios.Besides,we discuss the application of finite element simulation methods to the monitoring of the thermal management behavior of OCPCMs,and look into the potential future application areas of such materials.Finally,it is hoped that this review will provide guidance for the academic community in developing high-performance OCPCMs.
基金supported by the National Key Research and Development Program of China (Nos. 2022YFB3605203 and 2022YFB3608100)the National Natural Science Foundation of China (Nos. 62321004, 62227817, and 62374001)。
文摘The absence of large-size gallium nitride(GaN) substrates with low dislocation density remains a primary bottleneck for advancing GaN-based devices. Here, we demonstrate the achievement of 8-inch freestanding GaN substrates grown by hydride vapor phase epitaxy. Critical to this achievement is the improvement in gas-flow uniformity, which ensures exceptional thickness homogeneity and enables the crack-free growth of GaN. After laser lift-off(LLO) separation, the freestanding GaN substrate exhibits superior crystal quality, evidenced by full width at half maximum values of 68 and 54 arcsec for X-ray diffraction rocking curves of(002) and(102) planes, alongside a low dislocation density of 1.6 × 10^(6) cm^(-2). This approach establishes a robust pathway for the production of large-size GaN substrates, which are essential for advancing next-generation power electronics and high-efficiency photonics.
基金the financial support from the Central South University Fundamental Research Funds (Grant No.2025ZZTS0444)the Innovation-Driven Research Program(Grant No. 2023 CXQD053)+3 种基金the National Natural Science Foundation of China (Grant No. 52274310)the financial support (Project No.H202111040350002)the provision of the hydroxide precursors from Ningbo Ronbay New Energy Technology Co.,Ltdsupported in part by the High-Performance Computing Center of Central South University
文摘Cation disordering is a common issue in Ni-rich cathodes that significantly degrades cycle life and compromises safety.The cubic rock-salt phase formation and the slow oxidation kinetics of Ni^(2+)during solid-state sintering are widely recognized as the principal causes of these structural defects.To solve this issue,a topotactic soft-chemical precursor engineering strategy is proposed for use in aqueous solution.By utilizing the layered structure of the precursor,this method allows for selective proton extraction and efficient Ni^(2+)oxidation,along with rapid Li+intercalation to form a layered lithiated intermediate.This intermediate crystallizes without further phase transitions during subsequent heat treatment,preventing structural defects caused by complex phase evolution and slow ion diffusion.The resulting cathode exhibits a long-range ordered layered structure and a uniform phase distribution,enabling efficient Li+insertion and extraction.Electrochemical tests reveal a high discharge capacity of 229.6 mAh g^(−1)and an initial coulombic efficiency of 95.77%at 0.1 C,greatly exceeding the performance of a conventionally synthesized cathode(210.3 mAh g^(−1),88.93%).Improved Li^(+)transport kinetics reduces phase-transition hysteresis and alleviates stress concentration,resulting in better cycling stability with a capacity retention of 85.3%after 300 cycles,compared to 61.5%for the conventional sample.This work presents a scalable and effective synthesis route for Ni-rich cathodes with reduced structural disorder and extended lifespan,providing valuable insights into how the regulation of intermediate phases influences electrochemical performance in high-performance Ni-rich cathodes.
基金supported by the Carbon Emission Peak and Neutrality of Jiangsu Province(BE2022031-4)the National Natural Science Foundation of China(Key Program)(52131306,52122209,52403001)+1 种基金the Project on National Key R&D Program of China(2021YFB2400400)the Cultivation Program for The Excellent Doctoral Dissertation of Nanjing Tech University。
文摘Sodium-ion hybrid capacitors(SICs)offer inherent energy-power synergy but are constrained by mismatched kinetics and life spans between the anode and cathode materials.Two-dimensional MoS_(2)@C composites demonstrate excellent kinetics and structural stability,thanks to the built-in electric field of the carbon heterostructure and its adaptability to volume changes.Yet,the carbon shell imposes a physical barrier to interfacial Na^(+)diffusion,while deep discharge induces the formation of crystalline Na_(2)S,accompanied by severe volumetric expansion and sluggish reversibility—factors that accelerate capacity fading and structural degradation.To address these challenges,a trace-level Ni doping strategy is introduced,enabling precise modulation of the composite's interlayer structure,electronic configuration,and reaction pathway.Ni incorporation expands the MoS_(2) interlayer spacing,reconstructs short-range ordered nanocrystals within a hierarchically porous network,and promotes Na^(+)diffusion by weakening interlayer van der Waals forces.Orbital hybridization between Ni-3d and Mo-4d/S-3p states enhances electronic conductivity and reduces charge transfer resistance.Critically,Ni doping enhances electron transfer from Ni to sulfur,which weakens Na–S bonds and promotes the formation of amorphous Na_(2)S,thereby suppressing crystalline Na_(2)S and enabling a reversible MoS_(2)/Na_(2)S conversion mechanism for improved structural stability and cycling performance.As a result,the optimized MoS_(2)-Ni@C anode delivers a high reversible capacity of 334 mAh g^(-1)at 10 A g^(-1)with 68%retention after 10,000 cycles.When assembled into a SIC device(MoS_(2)-Ni@C//AC),it achieves an energy density of 135 Wh kg^(-1)at a power density of 60.8 kW kg^(-1)(based on anode mass),with 76%retention over 3,000 cycles.
基金financially supported by the Research and Development Program of China (2022YFA1505700)the National Natural Science Foundation of China (22475214, 22205232, 52102216)+6 种基金the Natural Science Foundation of Fujian Province (2023J06044,2022J01625, 2022-S-002)the Talent Plan of Shanghai BranchChinese Academy of Sciences (CASSHB-QNPD-2023-020)the Selfdeployment Project Research Program of Haixi Institutes,Chinese Academy of Sciences (CXZX-2022-JQ06 and CXZX-2022-GH03)the Anhui Key Laboratory of Nanomaterials and Nanotechnology,the Major Science and Technology Projects in Anhui Province(202305a12020006)the Open Project of State Key Laboratory of Inorganic Synthesis and Preparative Chemistry (2025-22)the Innovation Training Program for College Students(2025019300A, 20250193008)
文摘Co-free Li-rich Li_(1.2)Ni_(0.2)Mn_(0.6)O_(2)(LR)cathode shows the highest working capacity that can be applied to high-energy density Li-ion batteries(LIBs).However,poor cycle stability and voltage decay caused by phase transition are always hindering its further development.Herein,a novel medium-entropy Li-rich Mn-based cathode material(LRMEF)was synthesized via a simple sol-gel method.The introduction of multivalent ions(Al^(3+)/Cu^(2+)doping at Mn sites and F−doping at O sites)effectively mitigates the Jahn-Teller distortion of Mn ions and suppresses oxygen release.High-angle annular dark-field scanning transmission electron microscopy(HAADF-STEM)images confirm that this synergistic doping strategy induces the in-situ formation of an approximately 3 nm-thick spinel surface layer,which significantly enhances structural stability and ion diffusion kinetics.Besides,a series of in-situ/ex-situ characterization methods and density functional theory(DFT)calculations have been carried out to fundamentally shed light on the optimized structure-activity relationship and reaction mechanism.As a result,the LR material with entropy regulation and anion doping exhibits excellent cycling stability(189.2 mAh g^(−1)at 1 C with 84%capacity retention after 300 cycles),rate performance(164.1 mAh g^(−1)at 5 C),and voltage retention(82.7%at 1 C after 300 cycles),demonstrating great application prospects in future high-energy-density LIBs.
基金supported by the National Natural Science Foundation of China(22409065)the Guangdong Basic and Applied Basic Research Foundation(2022A1515011906)+2 种基金the China Postdoctoral Science Foundation(2023M731153)the Research Fund Program of Guangdong Provincial Key Laboratory of Fuel Cell Technologythe Postdoctoral Fellowship Program of CPSF(GZC20230868).
文摘The application of conventional manganese dioxide(MnO_(2))materials in sodium-ion supercapacitors(Na-SCs)is considerably limited by their low conductivity and structural instability.Biomimetic morphology engineering can optimize the electrochemical performance of MnO_(2).Here,based on the metal-organic frameworks(MOFs)-derived method and electrochemical reconstruction,a coral-like MnO_(2)structure integrated with a functional nitrogen-doped carbon(NC)coating is designed for Na-SC application.The bioinspired coral-like structure captures numerous electrolyte ions and increases the Na+concentration on the electrode surface,which is beneficial for optimizing the Na+transport pathway and accelerating the electrode reaction kinetics.Moreover,the coral-like crosslinked structure effectively enhances the mechanical properties,enabling the maintenance of the structure of MnO_(2)-based electrodes during long-term operation.Furthermore,in/ex-situ characterizations are performed to elucidate the mechanism of lattice transformation during electrochemical phase reconstruction.Additionally,the theoretical calculation and simulation results reveal the ion/electron dynamics in the fabricated electrode.The prepared electrode demonstrates excellent capacitance storage ability(340.7 F g^(−1)at 0.5 A g^(−1))and cycling stability(85.1%capacitance retention after 10,000 cycles).The assembled hybrid device exhibits exceptional life-span(82.0%capacitance retention after 10,000 cycles)and exceptional energy density(36.5 Wh kg^(−1)).This study provides a reliable biomimetic morphology design strategy for MnO_(2)cathodes,paving the way for the fabrication of high-performance Na-SCs.
基金financially supported by Natural Science Foundation of Guangdong province(2024A1515010228)CATARC Automotive Inspection Center Excellent Engineer Program(2023B0909050007).
文摘To address the challenge of balancing thermal management and thermal runaway mitigation,it is crucial to explore effective methods for enhancing the safety of lithium-ion battery systems.Herein,an innovative hydrated salt composite phase change material(HSCPCM)with dual phase transition temperature zones has been proposed.This HSCPCM,denoted as SDMA10,combines hydrophilic modified expanded graphite,an acrylic emulsion coating,and eutectic hydrated salts to achieve leakage prevention,enhanced thermal stability,cycling stability,and superior phase change behavior.Battery modules incorporating SDMA10 demonstrate significant thermal control capabilities.Specifically,the cylindrical battery modules with SDMA10 can maintain maximum operating temperatures below 55°C at 4 C discharge rate,while prismatic battery modules can keep maximum operating temperatures below 65°C at 2 C discharge rate.In extreme battery overheating conditions simulated using heating plates,SDMA10 effectively suppresses thermal propagation.Even when the central heating plate reaches 300°C,the maximum temperature at the module edge heating plates remains below 85°C.Further,compared to organic composite phase change materials(CPCMs),the battery module with SDMA10 can further reduce the peak thermal runaway temperature by 93°C and delay the thermal runaway trigger time by 689 s,thereby significantly decreasing heat diffusion.Therefore,the designed HSCPCM integrates excellent latent heat storage and thermochemical storage capabilities,providing high thermal energy storage density within the thermal management and thermal runaway threshold temperature range.This research will offer a promising pathway for improving the thermal safety performance of battery packs in electric vehicles and other energy storage systems.
基金financially supported by the National Key Research and Development Program of China (No. 2019YFA0708801)the National Natural Science Foundation of China (No. 51875125)。
文摘The water-quenched(WQ)2195 Al−Li alloy was subjected to stretching at different temperatures,from room temperature(RT)to−196℃(CT),to investigate the effect of cryogenic deformation on the aging precipitation behaviors and mechanical properties.The precipitation kinetics of the T1 phase and the microstructures in peak aging state were investigated through the differential scanning calorimetric(DSC)tests and electron microscopy observation.The results show that−196℃deformation produces a high dislocation density,which promotes the precipitation of the T1 phase and refines its sizes significantly.In addition,the grain boundary precipitates(GBPs)of−196℃-stretched samples are suppressed considerably due to the high dislocation density in the grain interiors,which increases the ductility.In comparison,the strength remains nearly constant.Thus,it is indicated that cryogenic forming has the potential to provide the shape and property control for the manufacture of critical components of aluminum alloys.
基金supported by the Natural Science Research Project of Anhui Province Education Department for Excellent Young Scholars(Grant No.2024AH030007)the National Natural Science Foundation of China(Grant No.52202001)。
文摘Conventional Tb^(3+)-doped phosphors typically suffer from concentration quenching once the doping level exceeds a critical threshold.Consequently,the development of Tb^(3+)phosphors with intrinsic resistance to concentration quenching has become a key research focus.In this work,we successfully synthesized KBi(MoO_(4))_(2):x Tb^(3+)(x=0-100 at%)(denoted as KBM:x Tb^(3+))phosphors via a high-temperature solid-state reaction.Remarkably,no concentration quenching was observed across the entire doping range.This anti-quenching behavior originates from the large Tb^(3+)-Tb^(3+)interionic distance(>5Å)inherent to the quasi-layered crystal structure,which effectively suppresses multipole-interaction-mediated energy migration.At full Tb^(3+)substitution(x=100 at%),the material undergoes a structural phase transition from the monoclinic KBM phase to the triclinicα-KTb(MoO_(4))_(2)(α-KTM)phase.Theα-KTM phosphor exhibits excellent thermal stability(activation energy=0.6129 eV)and a single-exponential decay profile,whereas KBM:x Tb^(3+)(x<100%)display double-exponential decay behaviors,attributed to dual energy transfer pathways.These findings provide new insights into the luminescence mechanisms of high-concentration rare-earth-doped systems and offer guidance for designing nextgeneration anti-quenching phosphors.
基金founded by the Ministry of Science and Higher Education of the Russian Federation,State assignments for research,registration No.1024032600084-8-1.3.2Study of the grain growth and the formation of polycrystalline structure as a result of phase transition(Section 6)was founded by the Russian Science Foundation,Project No.24-71-00078+3 种基金https://rscf.ru/en/project/24-71-00078/(accessed on 01 December 2025).Study of the orientation dependence of the phase transition of aluminum in Section 3 was founded by the Russian Science Foundation,Project No.24-19-00684https://rscf.ru/en/project/24-19-00684/(accessed on 01 December 2025).
文摘It is well known that aluminum and copper exhibit structural phase transformations in quasi-static and dynamic measurements,including shock wave loading.However,the dependence of phase transformations in a wide range of crystallographic directions of shock loading has not been revealed.In this work,we calculated the shock Hugoniot for aluminum and copper in different crystallographic directions([100],[110],[111],[112],[102],[114],[123],[134],[221]and[401])of shock compression using molecular dynamics(MD)simulations.The results showed a high pressure(>160 GPa for Cu and>40 GPa for Al)of the FCC-to-BCC transition.In copper,different characteristics of the phase transition are observed depending on the loading direction with the[100]compression direction being the weakest.The FCC-to-BCC transition for copper is in the range of 150–220 GPa,which is consistent with the existing experimental data.Due to the high transition pressure,the BCC phase transition in copper competes with melting.In aluminum,the FCC-to-BCC transition is observed for all studied directions at pressures between 40 and 50 GPa far beyond the melting.In all considered cases we observe the coexistence of HCP and BCC phases during the FCC-to-BCC transition,which is consistent with the experimental data and atomistic calculations;this HCP phase forms in the course of accompanying plastic deformation with dislocation activity in the parent FCC phase.The plasticity incipience is also anisotropic in bothmetals,which is due to the difference in the projections of stress on the slip plane for different orientations of the FCC crystal.MD modeling results demonstrate a strong dependence of the FCC-to-BCC transition on the crystallographic direction,in which the material is loaded in the copper crystals.However,MD simulations data can only be obtained for specific points in the stereographic direction space;therefore,for more comprehensive understanding of the phase transition process,a feed-forward neural network was trained using MD modeling data.The trained machine learning model allowed us to construct continuous stereographic maps of phase transitions as a function of stress in the shock-compressed state of metal.Due to appearance and growth of multiple centers of new phase,the FCC-to-BCC transition leads to formation of a polycrystalline structure from the parent single crystal.
基金supported by the National Key Research and Development Program of China(Grant No.2020YFC2200103)the Shandong Provincial Natural Science Foundation(Grant Nos.ZR2022LLZ006 and ZR2022LLZ011)+1 种基金the Innovation Program for Quantum Science and Technology(Grant Nos.2021ZD0300904 and 2021ZD0300903)the Key R&D Plan of Shandong Province(Grant No.2023CXPT105)。
文摘Optical phase transfer via fiber optics is the most effective method for optical frequency standard comparison on the scale below thousands of kilometers.However,the monotonic phase discrimination range of conventional optical phase-locked loops is limited,and link delays restrict the control bandwidth,which makes it a challenge to achieve a continuously reliable optical link.This paper presents an event-timing-based phase detection method that overcomes the monotonic phase discrimination range limitation of conventional phase-locked loops through dual-edge timestamp recording,achieving an optical phase measurement resolution on the order of 10 attoseconds.With such a technique,we established a 7-segment-cascaded optical link over 1402km of commercial fiber while sharing dense wavelength division multiplexing(DWDM)channels with live telecom traffic.The system maintained continuous operation for 11.7 days without phase cycle slips despite encountering 15 km aerial fiber noise up to 21000 rad^(2)·Hz^(−1)·km^(−1)at 1 Hz.Relative instabilities of the link are 3.7×10^(−15)at 1 s and 3.9×10^(−20)at 100000 s.
文摘In Chin.Phys.B 34114704(2025),Eq.(7)and the associated unit notation were incorrect.The correct ones are present here.Since Eq.(7)is an in-built expression in the simulation package,the correction is purely typographical and does not affect the simulation procedure,numerical results,or the conclusions.
基金supported by the National Natural Science Foundation of China(Nos.52370025,52372212)BUCEA Postgraduate Education and Teaching Quality Improvement Project(No.J2023016)the BUCEA Post Graduate Innovation Project(Nos.DG2023012 and PG2024073).
文摘Light-energy-driven semiconductor catalysis offers attractive ways to address environmental and energy crises.TiO_(2) is the most promising catalyst for photocatalysis,but the lack of charge-carrier separation efficiency severely limits its catalytic performance.In this study,we carried out crystal phase engineering to prepare in situ Z-scheme hetero-phase homojunction of anatase-rutile and clarified the structure-performance relationship.The efficiency of sulfamerazine removal by hetero-phase homojunction TiO_(2) nanotube arrays in a single-compartment photocatalytic fuel cell system was improved by 1.93 times compared to conventional anatase TiO_(2) nanotube arrays and the degradation pathways were revealed by the Fukui function combined with HP-LCMS.The successful construction of Z-scheme hetero-phase homojunction was confirmed by Raman,X-ray diffraction(XRD),and electron spin resonance(ESR),which combined with density functional theory(DFT)calculations revealed the key role of crystal phase engineering in the construction of hetero-phase homojunction.This work provides a novel strategy for the scientific design of titanium dioxide photocatalysts.
文摘Mechanoluminescent(ML)materials that emit light under mechanical stress are attracting growing attention for their potential in next-generation sensing,display,and energy-harvesting technologies[1].Among these,Mn/Cu-doped zinc sulfide(ZnS)has emerged as a leading candidate due to its bright emission,low activation threshold,and remarkable self-recovery over thousands of cycles[2-5].
基金supported by the National Natural Science Foundation of China(No.22276219)the foundation for Innovative Research Groups of the National Natural Science Foundation of China(No.52121004)+1 种基金the major program Natural Science Foundation of Hunan Province of China(No.2021JC0001)the Fundamental Research Funds for the Central Universities of Central South University(No.2024ZZTS0063).
文摘Beryllium-containing sludge(BCS)is a typical hazardous waste from Be smelting,which can cause serious harm to ecology and human health by releasing harmful Be if it is stored long-term in environment.Nonetheless,the occurrence of Be in BCS is unclear,which seriously hinders the development of pollution control technologies.In order to enhance the understanding of BCS,the occurrence of Be and the microscale interactions with coexisting phases were investigated for the first time.It was found that CaSO_(4)·2H_(2)O and amorphous SiO_(2) are the primary phases of BCS.The simulated experiments of purified materials showed that Be interacted with CaSO_(4)·2H_(2)O and amorphous SiO_(2).Be can enter into the lattice of CaSO_(4)·2H_(2)O mainly as free Be2+.Amorphous SiO_(2) can adsorb Be2+particularly at a pH range of 3–5.The dissolution behavior experiment of BCS shows that about 52%of the Be is readily extracted under acidic conditions,which refers to the Be of independent occurrence.In contrast,the remaining 48%of Be can be extracted only after the CaSO_(4)·2H_(2)O has completely dissolved.Hence,CaSO_(4)·2H_(2)O is identified as the key occurrence phase which determines the highly efficient dissolution of Be.As a result,this study enhances the understanding of BCS and lays the foundation for the development of Be separation technologies.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB0530000)the Discipline Construction Foundation of“Double World-class Project”.
文摘Laser wakefield accelerators(LWFAs)offer acceleration gradients up to 1000 times higher than those of conventional radio-frequency accelerators,offering a pathway to significantly more compact and cost-effective accelerator systems.This breakthrough opens up new possibilities for laboratory-scale light sources.All-optical inverse Compton scattering(AOCS)sources driven by LWFAs produce high-brightness,quasimonochromatic X rays with micrometer-scale source sizes,delivering the spatial coherence and resolution required for X-ray phase-contrast imaging(XPCI).These features position AOCS X-ray sources as promising tools for applications in biology,medicine,physics,and materials science.However,previous AOCS-based imaging studies have primarily focused on X-ray absorption imaging.In this work,we report successful experimental demonstrations of edge-enhanced in-line XPCI using energy-tunable,quasi-monochromatic AOCS X rays.With a spatial resolution of~20μm,our results clearly show the potential of high-resolution,AOCS-based XPCI applications.
基金National Natural Science Foundation of China(12405168)The Fundamental Research Funds for the Central Universities,China(2024CDJXY004)。
文摘[Background]High harmonic cavities are widely used in electron storage rings to lengthen thebunch,lower the bunch peak current,thereby reducing the IBS effect,enhancing the Touschek lifetime,as well asproviding Landau damping,which is particularly important for storage rings operating with ultra-low emittance or atlow beam energy.[Purpose]To further increase the bunch length without additional hardware costs,the phasemodulation in a dual-RF system is considered.[Methods]In this paper,turn-by-turn simulations incorporating randomsynchrotron radiation excitation are conducted,and a brief analysis is presented to explain the bunch lengtheningmechanism.[Results]Simulation results reveal that the peak current can be further reduced,thereby mitigating IBSeffects and enhancing the Touschek lifetime.Although the energy spread increases,which tends to reduce thebrightness of higher-harmonic radiation from the undulator,the brightness of the fundamental harmonic can,in fact,beimproved.
基金granted by the National Natural Science Foundation of China(No.12047503)Wenzhou Institute,University of Chinese Academy of Sciences(No.WIUCASQD2023009)。
文摘Active matter is a non-equilibrium condensed system consisting of self-propelled particles capable of converting stored or ambient energy into collective motion.Typical active matter systems include cytoskeleton biopolymers,swimming bacteria,artificial swimmers,and animal herds.In contrast to wet active matter,dry active matter is an active system characterized by the absence of significant hydrodynamic interactions and conserved momentum.In dry active matter,the role of surrounding fluids is providing viscous friction at low Reynolds numbers and can be neglected at high Reynolds numbers.This review offers a comprehensive overview of recent experimental,computational,and theoretical advances in understanding phase transitions and critical phenomena in dry aligning active matter,including polar particles,self-propelled rods,active nematics,and their chiral counterparts.Various ways of determining phase transition points as well as non-equilibrium phenomena,such as collective motion,cluster formation,and creation and annihilation of topological defects are reviewed.
