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
Theβsolidifiedγ-TiAl alloy holds important application value in the aerospace industry,while its com-plex phase compositions and geometric structures pose challenges to its microstructure control during the thermal-...Theβsolidifiedγ-TiAl alloy holds important application value in the aerospace industry,while its com-plex phase compositions and geometric structures pose challenges to its microstructure control during the thermal-mechanical process.The microstructure evolution of Ti-43Al-4Nb-1Mo-0.2B alloy at 1200℃/0.01 s−1 was investigated to clarify the coupling role of dynamic recrystallization(DRX)and phase transformation.The results revealed that the rate of DRX inα2+γlamellar colonies was comparatively slower than that inβo+γmixed structure,instead being accompanied by intense lamellar kinking and rotation.The initiation and development rates of DRX inα2,βo,andγphases decreased sequentially.The asynchronous DRX of the various geometric structures and phase compositions resulted in the un-even deformed microstructure,and the dynamic softening induced by lamellar kinking and rotation was replaced by strengthened DRX as strain increased.Additionally,the blockyα2 phase and the terminals ofα2 lamellae were the preferential DRX sites owing to the abundant activated slip systems.Theα2→βo transformation within lamellar colonies facilitated DRX and fragment ofα2 lamellae,while theα2→γtransformation promoted the decomposition ofα2 lamellae and DRX ofγlamellae.Moreover,the var-iedβo+γmixed structures underwent complicated evolution:(1)Theγ→βo transformation occurred at boundaries of lamellar colonies,followed by simultaneous DRX ofγlamellar terminals and neighboringβo phase;(2)DRX occurred earlier within the band-likeβo phase,with the delayed DRX in enclosedγphase;(3)DRX within theβo synapses and neighboringγphase was accelerated owing to generation of elastic stress field;(4)Dispersedβo particles triggered particle stimulated nucleation(PSN)ofγphase.Eventually,atomic diffusion along crystal defects inβo andγphases caused fracture of band-likeβo phase and formation of massiveβo particles,impeding grain boundary migration and hindering DRXed grain growth ofγphase.展开更多
In-situ tensile tests were conducted on a chemically corroded third-generation single-crystal superalloy DD9 at 980 and 1100℃.The phase transformation in the surface areas during the tensile process was analyzed usin...In-situ tensile tests were conducted on a chemically corroded third-generation single-crystal superalloy DD9 at 980 and 1100℃.The phase transformation in the surface areas during the tensile process was analyzed using field emission scanning electron microscope,energy dispersive X-ray spectroscope,electron probe X-ray microanalysis,and transmission electron microscope.The phase transformation mechanism on the surface and the influence mechanism were studied through observation and dynamic calculation.During tensile tests at elevated temperatures,chemical corrosion promotes the precipitation of topologically close-packed(tcp)μphase andσphase on the alloy surface.Both the precipitation amount and size of these two phases on the surface at 1100℃are greater than those at 980℃.The precipitation of tcp phase on the alloy surface results in the formation of an influence layer on the surface area,and the distribution characteristics of alloying elements are significantly different from those of the substrate.The depth of the influence layer at 1100℃is greater than that at 980℃.The precipitation of tcp phase prompts the phase transition fromγphase toγ′phase around the tcp phase.展开更多
Aiming at the problems of complex process and high cost in the production of potassium bromide at present,the solubility data and the phase diagram of the quaternary system KBr-MgBr_(2)-K_(2)SO_(4)-MgSO_(4)-H_(2)O at ...Aiming at the problems of complex process and high cost in the production of potassium bromide at present,the solubility data and the phase diagram of the quaternary system KBr-MgBr_(2)-K_(2)SO_(4)-MgSO_(4)-H_(2)O at 298.15 K were studied using the isothermal dissolution equilibrium method.The results showed that there are eight invariant points,sixteen univariant curves,and nine crystallization regions in the phase diagram which is complex and contains two double salts(K_(2)SO_(4)·MgSO_(4)·6H_(2)O and KBr·MgBr_(2)·6H_(2)O)and a metastable phase(MgSO_(4)·5H_(2)O).On the basis of the Pitzer model and HW model,the solubilities of the quaternary system were calculated,with which the corresponding phase diagram was plotted.By comparison,the evaluated phase diagram is in accordance with the measured one.Through analysis,the phase diagrams of the quaternary system at(298.15 and 323.15)K were combined to put forward a process to separate KBr from the system by evaporation and crystallization,which realized the full circulation of the mother solution.展开更多
The degradation and nonlinear interactions of a two-breather solution of the Mel’nikov equation are analyzed.By modulating the phase shift and limit method,we prove that in different regions near the non-singular bou...The degradation and nonlinear interactions of a two-breather solution of the Mel’nikov equation are analyzed.By modulating the phase shift and limit method,we prove that in different regions near the non-singular boundaries,there are four kinds of solutions with repulsive interaction or attractive interaction in addition to the two-breather solution.They are the interaction solution between soliton and breather,the two-soliton solution,and the two-breather solution with small amplitude,which all exhibit repulsive interactions;and the two-breather solution with small amplitude,which exhibits attractive interaction.Interestingly,a new breather acts as a messenger to transfer energy during the interaction between two breather solutions with small amplitude.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
New discovery in whisker growth on Cr-Al-B MAB phase,which was formed during hot-dip aluminizing and subsequent thermal diffusion treatment of Fe-Cr-B cast steel,after cultivation under 400℃,was found.Specifically,al...New discovery in whisker growth on Cr-Al-B MAB phase,which was formed during hot-dip aluminizing and subsequent thermal diffusion treatment of Fe-Cr-B cast steel,after cultivation under 400℃,was found.Specifically,along with the growth of Sn whiskers on the whitened Cr-Al-B MAB phase,Al whiskers also formed,mainly attributed to the thermal activation of whisker cultivation at 400℃and promotion effect of Sn in the Cr-(Al,Sn)-B MAB phase solid solution.Partial Al whiskers,interspersed with small amounts of Sn,exhibited transparency under the scanning electron microscopy image.These whiskers underwent random growth and sucking back into the matrix simultaneously.The temperature during whisker cultivation had a significant effect on the whisker growth.展开更多
We investigate the parity-time(PT)symmetry-breaking quantum phase transition in a one-dimensional(1D)bosonic lattice featuring cavity-mediated long-range interactions and spatially staggered dissipation.By mapping the...We investigate the parity-time(PT)symmetry-breaking quantum phase transition in a one-dimensional(1D)bosonic lattice featuring cavity-mediated long-range interactions and spatially staggered dissipation.By mapping the system to an effective spin chain under the constraints of hard-core bosons and integrating the mean-field decoupling approach with biorthogonal basis formalism,we derive a self-consistency equation.Numerical simulation results validate that the derived equation quantitatively captures thePT-symmetry order parameter’s phase diagram.Our findings reveal that coherent hopping maintainsPTsymmetry through quantum fluctuations.Conversely,cavity-engineered long-range interactions,in synergy with staggered dissipation,act in opposition to drive symmetry breaking.This competitive interplay can inspire further exploration of tunable quantum phase transitions in non-Hermitian systems.展开更多
The vapor diffusion and transport resulting from steam generator tube rupture(SGTR)accidents are a major concern threatening lead-based reactor core safety.In this study,a high-parameter SGTR experimental platform and...The vapor diffusion and transport resulting from steam generator tube rupture(SGTR)accidents are a major concern threatening lead-based reactor core safety.In this study,a high-parameter SGTR experimental platform and the multi-phase multi-physics processes numerical simulation were developed to investigate the phase behavior and interaction mechanisms.This study revealed the interaction mechanisms of lead-bismuth liquid metal and water driven by flash vaporization,jet impingement boiling,and moderate boiling.The migration and evolution of the discrete phases(vapor-water mixture)were inferred from the temperature transient laws and a numerical simulation.The results revealed that the evolution of the discrete phases consists of three stages:cavity formation,flanking diffusion,and stable up-floating.The jet pressure significantly extended the disturbance period.Variations in the water temperature mainly affected the depressurization boiling process,altering the diffusion region of the discrete phases.The temperature of the liquid metal and the duration of the jet had a minimal impact on the behavior of the discrete phases.This study provides a crucial reference for constructing a complete picture of accident evolution.展开更多
Purpose–This study aims to enhance the accuracy of key entity extraction from railway accident report texts and address challenges such as complex domain-specific semantics,data sparsity and strong inter-sentence sem...Purpose–This study aims to enhance the accuracy of key entity extraction from railway accident report texts and address challenges such as complex domain-specific semantics,data sparsity and strong inter-sentence semantic dependencies.A robust entity extraction method tailored for accident texts is proposed.Design/methodology/approach–This method is implemented through a dual-branch multi-task mutual learning model named R-MLP,which jointly performs entity recognition and accident phase classification.The model leverages a shared BERT encoder to extract contextual features and incorporates a sentence span indexing module to align feature granularity.A cross-task mutual learning mechanism is also introduced to strengthen semantic representation.Findings–R-MLP effectively mitigates the impact of semantic complexity and data sparsity in domain entities and enhances the model’s ability to capture inter-sentence semantic dependencies.Experimental results show that R-MLP achieves a maximum F1-score of 0.736 in extracting six types of key railway accident entities,significantly outperforming baseline models such as RoBERTa and MacBERT.Originality/value–This demonstrates the proposed method’s superior generalization and accuracy in domainspecific entity extraction tasks,confirming its effectiveness and practical value.展开更多
In this paper,we present a broadband,high-extinction-ratio,nonvolatile 2×2 Mach-Zehnder interfer⁃ometer(MZI)optical switch based on the phase change material Sb_(2)Se_(3).The insertion loss(IL)is 0.84 dB and the ...In this paper,we present a broadband,high-extinction-ratio,nonvolatile 2×2 Mach-Zehnder interfer⁃ometer(MZI)optical switch based on the phase change material Sb_(2)Se_(3).The insertion loss(IL)is 0.84 dB and the extinction ratio(ER)reaches 28.8 dB at the wavelength of 1550 nm.The 3 dB bandwidth is greater than 150 nm.Within the 3 dB bandwidth,the ER is greater than 20.3 dB and 16.3 dB at bar and cross states,respectively.The power consumption for crystallization and amorphization of Sb_(2)Se_(3) is 105.86 nJ and 49 nJ,respectively.The switch holds significant promise for optical interconnects and optical computing 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
The mechanical properties of Mg–Al–Ca alloys are significantly affected by their Laves phases,including the Al_(2)Ca phase.Laves phases are generally considered to be brittle and have a detrimental effect on the duc...The mechanical properties of Mg–Al–Ca alloys are significantly affected by their Laves phases,including the Al_(2)Ca phase.Laves phases are generally considered to be brittle and have a detrimental effect on the ductility of Mg.Recently,the Al_(2)Ca phase was shown to undergo plastic deformation in a dilute Mg-Al-Ca alloy to increase the ductility and work hardening of the alloy.In the present study,we investigated the extent to which the deformation of Al_(2)Ca is driven by dislocations in the Mg matrix by simulating the interactions between the basal edge dislocations and Al_(2)Ca particles.In particular,the effects of the interparticle spacing,particle orientation,and particle size were considered.Shearing of small particles and dislocation cross-slips near large particles were observed.Both events contribute to strengthening,and accommodate to plasticity.The shear resistance of the dislocation to bypass the particles increased as the particle size increased.The critical resolved shear stress(CRSS)for activating dislocations and stacking faults was easier to reach for small Al_(2)Ca particles owing to the higher local shear stress,which is consistent with the experimental observations.Overall,this work elucidates the driving force for Al_(2)Ca particles in Mg–Al–Ca alloys to undergo plastic deformation.展开更多
Wide-bandgap mixed-halide perovskites,particularly CsPbIBr_(2),hold great promise for multi-junction solar cells due to their well-matched bandgap and all-inorganic material system.However,their inherent susceptibilit...Wide-bandgap mixed-halide perovskites,particularly CsPbIBr_(2),hold great promise for multi-junction solar cells due to their well-matched bandgap and all-inorganic material system.However,their inherent susceptibility to light-induced phase segregation(LIPS)limits efficiency and stability.In this work,we investigate the effect of three organic additives-4-cyclopentene-1,3-dione(CPD),maleimide(HPD),and 3,4-dibromo-1H-pyrrole-2,5(2H,5H)-dione(BrPD)-on LIPS in wide-bandgap CsPbIBr_(2)perovskite films.The additives form various chemical interactions,including coordination bonds,hydrogen bonds,and ionic bonds,with I^(-)and undercoordinated Pb^(2+)ions,among which BrPD has the strongest interaction.This interaction regulates crystallization and improves film morphology.The BrPD-modified films have the largest grain size and the highest light stability,suppressing LIPS,enhancing carrier transfer,and improving device performance.BrPD-modified CsPbIBr_(2)-based solar cells achieve a power conversion efficiency(PCE)of 11.34%,outperforming the control(8.96%)and other additives.Moreover,BrPDmodified devices show excellent stability,retaining 94%of their initial PCE after 60 min of continuous light exposure.This work highlights the potential of strategically selected organic additives to enhance the stability and performance of perovskite solar cells,offering valuable insights for the design of high-efficiency and long-lasting perovskite-based optoelectronic devices.展开更多
A dual-phase synergistic enhancement method was adopted to strengthen the Al-Mn-Mg-Sc-Zr alloy fabricated by laser powder bed fusion(LPBF)by leveraging the unique advantages of Er and TiB_(2).Spherical powders of 0.5w...A dual-phase synergistic enhancement method was adopted to strengthen the Al-Mn-Mg-Sc-Zr alloy fabricated by laser powder bed fusion(LPBF)by leveraging the unique advantages of Er and TiB_(2).Spherical powders of 0.5wt%Er-1wt%TiB_(2)/Al-Mn-Mg-Sc-Zr nanocomposite were prepared using vacuum homogenization technique,and the density of samples prepared through the LPBF process reached 99.8%.The strengthening and toughening mechanisms of Er-TiB_(2)were investigated.The results show that Al_(3)Er diffraction peaks are detected by X-ray diffraction analysis,and texture strength decreases according to electron backscatter diffraction results.The added Er and TiB_(2)nano-reinforcing phases act as heterogeneous nucleation sites during the LPBF forming process,hindering grain growth and effectively refining the grains.After incorporating the Er-TiB_(2)dual-phase nano-reinforcing phases,the tensile strength and elongation at break of the LPBF-deposited samples reach 550 MPa and 18.7%,which are 13.4%and 26.4%higher than those of the matrix material,respectively.展开更多
As electronic technology continues to evolve towards miniaturization and integration,the demand for micro-refrigeration technology in microelectronic systems is increasing.Ferroelectric(FE)refrigeration technology bas...As electronic technology continues to evolve towards miniaturization and integration,the demand for micro-refrigeration technology in microelectronic systems is increasing.Ferroelectric(FE)refrigeration technology based on the electrocaloric effect(ECE)has emerged as a highly promising candidate in this field,due to its advantages of high energy efficiency,simple structure,easy miniaturization,low cost,and environmental friendliness.The EC performance of FE materials essentially depends on the phase transition features under the coupled electric and thermal fields,making the E–T phase diagram a core tool for decoding the underlying mechanism of ECE.This paper reviews the development of EC materials,focusing on the comprehensive study of E–T phase diagrams.By correlating the microscopic phase structure of FE materials with the macroscopic physical properties,it clarifies the manipulation mechanism for enhanced ECE performance,providing theoretical support for the targeted design of high-performance EC materials.In the future,the introduction of data-driven methods is expected to enable the high-throughput construction of FE phase diagrams,thereby accelerating the optimization of high-performance EC materials and promoting the practical application of FE refrigeration technology.展开更多
The coating material is considered as the key of solid-phase microextraction(SPME)due to the fact that which has much effect on the selectivity and sensitivity of the analytical method.Herein,the porous hollow carbon ...The coating material is considered as the key of solid-phase microextraction(SPME)due to the fact that which has much effect on the selectivity and sensitivity of the analytical method.Herein,the porous hollow carbon nanospheres(PHCNs)were synthesized by selectively removing the interior part of solid inhomogeneous nanospheres with acetone.Using PHCNs as new coating material,a SPME fiber was prepared.To the best of our knowledge,PHCNs was utilized as a SPME fiber coating for the first time.The fiber coating material PHCNs demonstrated excellent thermal stability(>800℃)and long usage lifespan(≥60 times).A headspace SPME(HS-SPME)was established to non-contact extract and enrich polycyclic aromatic hydrocarbons(PAHs)prior to gas chromatography-flame ionization detector(GC-FID)analysis.The HS-SPME not only can eliminate non-volatile interferences from matrix,but also be able to protect fiber coating and prolong lifespan of fiber prober.The linearity in the linear range of 0.01-30 ng/m L and limits of detection from 0.003 ng/mL to 0.006 ng/mL were obtained by HS-SPME-GC-FID with PHCNs as fiber coating.The enrichment factors were calculated as 5420-9211 compared with conventional direct introduce analysis.The spiked recoveries of real samples including campus lake water and lime tree honey were obtained from 80.93%to 118.0%with relative standard deviation no higher than 10.6%.The π-π stacking interaction,CH/π interaction,and unique built-in cavities significantly enhance the extraction performance of PHCNs coating fiber to PAHs.This work demonstrated that the PHCNs as fiber coating materials present good application prospects for the extraction and enrichment of trace PAHs from complex matrixes.展开更多
Precise forecasts of wildfire danger are crucial for proactive fuel management and emergency responses,yet they pose a challenge at the subseasonal scale due to limitations in prediction capabilities and a gap between...Precise forecasts of wildfire danger are crucial for proactive fuel management and emergency responses,yet they pose a challenge at the subseasonal scale due to limitations in prediction capabilities and a gap between forecast outputs and the needs of decision-makers.This study introduces an innovative hybrid modeling framework that integrates artificial intelligence(AI)with climate dynamic prediction systems to accurately forecast High Fire-Danger Days(HFDDs)for the following month.These HFDDs are derived from historical satellite fire data and the optimum fire danger index,with a particular focus on Southwest China as a case study.The AI module,based on the ResNet-18 neural network model,integrates observational and physically constrained analysis to establish links between HFDDs and optimal predictors of atmospheric circulation from both the concurrent and preceding months.Leveraging climate dynamical forecasting,this hybrid model provides more reliable deterministic predictions for monthly HFDDs than conventional methods that rely solely on terrestrial variables such as precipitation.More importantly,the integration of dynamical ensemble prediction enhances the model’s capability for skillful probabilistic predictions of HFDDs,facilitating the creation of customized fire danger outlooks and emergency action maps tailored to stakeholders’needs.The model’s added economic value was also evaluated,demonstrating its potential to improve decision-making in disaster management and bridge the“last-mile gap”in climate service delivery.This work contributes to the Seamless Prediction and Services for Sustainable Natural and Built Environment(SEPRESS)Program(2025–32),under the United Nations Educational Scientific and Cultural Organization(UNESCO)International Decade of Sciences for Sustainable Development(2024–33).展开更多
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financially supported by the National Key Re-search and Development Program of China(No.2021YFB3702604)the National Natural Science Foundation of China(No.52174377)+1 种基金the Chongqing Natural Science Foundation Project(No.CSTB2023NSCQ-MSX0824)This work was also supported by the Shaanxi Materials Analysis&Research Center and the Analytical&Testing Center of NPU.
文摘Theβsolidifiedγ-TiAl alloy holds important application value in the aerospace industry,while its com-plex phase compositions and geometric structures pose challenges to its microstructure control during the thermal-mechanical process.The microstructure evolution of Ti-43Al-4Nb-1Mo-0.2B alloy at 1200℃/0.01 s−1 was investigated to clarify the coupling role of dynamic recrystallization(DRX)and phase transformation.The results revealed that the rate of DRX inα2+γlamellar colonies was comparatively slower than that inβo+γmixed structure,instead being accompanied by intense lamellar kinking and rotation.The initiation and development rates of DRX inα2,βo,andγphases decreased sequentially.The asynchronous DRX of the various geometric structures and phase compositions resulted in the un-even deformed microstructure,and the dynamic softening induced by lamellar kinking and rotation was replaced by strengthened DRX as strain increased.Additionally,the blockyα2 phase and the terminals ofα2 lamellae were the preferential DRX sites owing to the abundant activated slip systems.Theα2→βo transformation within lamellar colonies facilitated DRX and fragment ofα2 lamellae,while theα2→γtransformation promoted the decomposition ofα2 lamellae and DRX ofγlamellae.Moreover,the var-iedβo+γmixed structures underwent complicated evolution:(1)Theγ→βo transformation occurred at boundaries of lamellar colonies,followed by simultaneous DRX ofγlamellar terminals and neighboringβo phase;(2)DRX occurred earlier within the band-likeβo phase,with the delayed DRX in enclosedγphase;(3)DRX within theβo synapses and neighboringγphase was accelerated owing to generation of elastic stress field;(4)Dispersedβo particles triggered particle stimulated nucleation(PSN)ofγphase.Eventually,atomic diffusion along crystal defects inβo andγphases caused fracture of band-likeβo phase and formation of massiveβo particles,impeding grain boundary migration and hindering DRXed grain growth ofγphase.
文摘In-situ tensile tests were conducted on a chemically corroded third-generation single-crystal superalloy DD9 at 980 and 1100℃.The phase transformation in the surface areas during the tensile process was analyzed using field emission scanning electron microscope,energy dispersive X-ray spectroscope,electron probe X-ray microanalysis,and transmission electron microscope.The phase transformation mechanism on the surface and the influence mechanism were studied through observation and dynamic calculation.During tensile tests at elevated temperatures,chemical corrosion promotes the precipitation of topologically close-packed(tcp)μphase andσphase on the alloy surface.Both the precipitation amount and size of these two phases on the surface at 1100℃are greater than those at 980℃.The precipitation of tcp phase on the alloy surface results in the formation of an influence layer on the surface area,and the distribution characteristics of alloying elements are significantly different from those of the substrate.The depth of the influence layer at 1100℃is greater than that at 980℃.The precipitation of tcp phase prompts the phase transition fromγphase toγ′phase around the tcp phase.
基金supported by the National Natural Science Foundation of China (22008049 and 22478095)Hebei Provincial Key Research Projects (22374101D)+3 种基金Central Guidance Project for Local Science and Technology Development from S&T Program of Hebei (246Z1009G)Special Proof-of-concept Project on Basic Research from S&T Program of Hebei (E2024402143)Science and Technology Project of Hebei Education Department (CXY2023004)Hebei University of Engineering Doctoral Scientific Research Start-up Foundation (SJ2401002210).
文摘Aiming at the problems of complex process and high cost in the production of potassium bromide at present,the solubility data and the phase diagram of the quaternary system KBr-MgBr_(2)-K_(2)SO_(4)-MgSO_(4)-H_(2)O at 298.15 K were studied using the isothermal dissolution equilibrium method.The results showed that there are eight invariant points,sixteen univariant curves,and nine crystallization regions in the phase diagram which is complex and contains two double salts(K_(2)SO_(4)·MgSO_(4)·6H_(2)O and KBr·MgBr_(2)·6H_(2)O)and a metastable phase(MgSO_(4)·5H_(2)O).On the basis of the Pitzer model and HW model,the solubilities of the quaternary system were calculated,with which the corresponding phase diagram was plotted.By comparison,the evaluated phase diagram is in accordance with the measured one.Through analysis,the phase diagrams of the quaternary system at(298.15 and 323.15)K were combined to put forward a process to separate KBr from the system by evaporation and crystallization,which realized the full circulation of the mother solution.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.52171251 and U21062251)Program of Science and Technology Innovation of Dalian(Grant No.2022JJ12GX036).
文摘The degradation and nonlinear interactions of a two-breather solution of the Mel’nikov equation are analyzed.By modulating the phase shift and limit method,we prove that in different regions near the non-singular boundaries,there are four kinds of solutions with repulsive interaction or attractive interaction in addition to the two-breather solution.They are the interaction solution between soliton and breather,the two-soliton solution,and the two-breather solution with small amplitude,which all exhibit repulsive interactions;and the two-breather solution with small amplitude,which exhibits attractive interaction.Interestingly,a new breather acts as a messenger to transfer energy during the interaction between two breather solutions with small amplitude.
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financial support from the National Natural Science Foundation of China(Grant Nos.42066003 and 51701053)Hainan Province Science and Technology Special Fund(Grant No.ZDYF2023GXJS148)+1 种基金General Program of Natural Science Foundation of Hainan Province(Grant Nos.420RC522 and 517076)Evaluation Project of Guangdong Provincial Key Laboratory(Grant No.2023B1212060043).
文摘New discovery in whisker growth on Cr-Al-B MAB phase,which was formed during hot-dip aluminizing and subsequent thermal diffusion treatment of Fe-Cr-B cast steel,after cultivation under 400℃,was found.Specifically,along with the growth of Sn whiskers on the whitened Cr-Al-B MAB phase,Al whiskers also formed,mainly attributed to the thermal activation of whisker cultivation at 400℃and promotion effect of Sn in the Cr-(Al,Sn)-B MAB phase solid solution.Partial Al whiskers,interspersed with small amounts of Sn,exhibited transparency under the scanning electron microscopy image.These whiskers underwent random growth and sucking back into the matrix simultaneously.The temperature during whisker cultivation had a significant effect on the whisker growth.
基金supported by the National Natural Science Foundation of China(Grant No.12375025).
文摘We investigate the parity-time(PT)symmetry-breaking quantum phase transition in a one-dimensional(1D)bosonic lattice featuring cavity-mediated long-range interactions and spatially staggered dissipation.By mapping the system to an effective spin chain under the constraints of hard-core bosons and integrating the mean-field decoupling approach with biorthogonal basis formalism,we derive a self-consistency equation.Numerical simulation results validate that the derived equation quantitatively captures thePT-symmetry order parameter’s phase diagram.Our findings reveal that coherent hopping maintainsPTsymmetry through quantum fluctuations.Conversely,cavity-engineered long-range interactions,in synergy with staggered dissipation,act in opposition to drive symmetry breaking.This competitive interplay can inspire further exploration of tunable quantum phase transitions in non-Hermitian systems.
基金supported by the National Natural Science Foundation of China(Nos.U20B2011 and 123B2086)。
文摘The vapor diffusion and transport resulting from steam generator tube rupture(SGTR)accidents are a major concern threatening lead-based reactor core safety.In this study,a high-parameter SGTR experimental platform and the multi-phase multi-physics processes numerical simulation were developed to investigate the phase behavior and interaction mechanisms.This study revealed the interaction mechanisms of lead-bismuth liquid metal and water driven by flash vaporization,jet impingement boiling,and moderate boiling.The migration and evolution of the discrete phases(vapor-water mixture)were inferred from the temperature transient laws and a numerical simulation.The results revealed that the evolution of the discrete phases consists of three stages:cavity formation,flanking diffusion,and stable up-floating.The jet pressure significantly extended the disturbance period.Variations in the water temperature mainly affected the depressurization boiling process,altering the diffusion region of the discrete phases.The temperature of the liquid metal and the duration of the jet had a minimal impact on the behavior of the discrete phases.This study provides a crucial reference for constructing a complete picture of accident evolution.
基金funded by the Technology Research and Development Plan Program of China State Railway Group Co.,Ltd.(No.Q2024T001)the Foundation of China Academy of Railway Sciences Co.,Ltd.(No:2024YJ259).
文摘Purpose–This study aims to enhance the accuracy of key entity extraction from railway accident report texts and address challenges such as complex domain-specific semantics,data sparsity and strong inter-sentence semantic dependencies.A robust entity extraction method tailored for accident texts is proposed.Design/methodology/approach–This method is implemented through a dual-branch multi-task mutual learning model named R-MLP,which jointly performs entity recognition and accident phase classification.The model leverages a shared BERT encoder to extract contextual features and incorporates a sentence span indexing module to align feature granularity.A cross-task mutual learning mechanism is also introduced to strengthen semantic representation.Findings–R-MLP effectively mitigates the impact of semantic complexity and data sparsity in domain entities and enhances the model’s ability to capture inter-sentence semantic dependencies.Experimental results show that R-MLP achieves a maximum F1-score of 0.736 in extracting six types of key railway accident entities,significantly outperforming baseline models such as RoBERTa and MacBERT.Originality/value–This demonstrates the proposed method’s superior generalization and accuracy in domainspecific entity extraction tasks,confirming its effectiveness and practical value.
基金Supported by the National Natural Science Foundation of China(62204250)Autonomous deployment project of State Key Laboratory of Materials for Integrated Circuits(SKLJC-Z2024-A05).
文摘In this paper,we present a broadband,high-extinction-ratio,nonvolatile 2×2 Mach-Zehnder interfer⁃ometer(MZI)optical switch based on the phase change material Sb_(2)Se_(3).The insertion loss(IL)is 0.84 dB and the extinction ratio(ER)reaches 28.8 dB at the wavelength of 1550 nm.The 3 dB bandwidth is greater than 150 nm.Within the 3 dB bandwidth,the ER is greater than 20.3 dB and 16.3 dB at bar and cross states,respectively.The power consumption for crystallization and amorphization of Sb_(2)Se_(3) is 105.86 nJ and 49 nJ,respectively.The switch holds significant promise for optical interconnects and optical computing 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funded by the National Natural Science Foundation of China(nos.51631006 and 51825101)。
文摘The mechanical properties of Mg–Al–Ca alloys are significantly affected by their Laves phases,including the Al_(2)Ca phase.Laves phases are generally considered to be brittle and have a detrimental effect on the ductility of Mg.Recently,the Al_(2)Ca phase was shown to undergo plastic deformation in a dilute Mg-Al-Ca alloy to increase the ductility and work hardening of the alloy.In the present study,we investigated the extent to which the deformation of Al_(2)Ca is driven by dislocations in the Mg matrix by simulating the interactions between the basal edge dislocations and Al_(2)Ca particles.In particular,the effects of the interparticle spacing,particle orientation,and particle size were considered.Shearing of small particles and dislocation cross-slips near large particles were observed.Both events contribute to strengthening,and accommodate to plasticity.The shear resistance of the dislocation to bypass the particles increased as the particle size increased.The critical resolved shear stress(CRSS)for activating dislocations and stacking faults was easier to reach for small Al_(2)Ca particles owing to the higher local shear stress,which is consistent with the experimental observations.Overall,this work elucidates the driving force for Al_(2)Ca particles in Mg–Al–Ca alloys to undergo plastic deformation.
基金supported financially by the National Key R&D Program of China(Grant No.2023YFE0111500)the National Natural Science Foundation of China(Grant Nos.52321006,T2394480,T2394484,22109143,22475196,22479131)+11 种基金the Research Grants Council of Hong Kong(CRF C4005-22YRGC Senior Research Fellowship Scheme(SRFS2223-5S01))the Joint Fund for Provincial Science and Technology R&D Program of Henan(grant no.242301420051)the Opening Project of the State Key Laboratory of Advanced Technology for Float Glass(grant no.2022KF04)the China Postdoctoral Innovative Talent Support Program(grant no.BX2021271)the China Postdoctoral Science Foundation(grant no.2022M712851)the Graduate Education Reform Project of Henan Province(Grant No.2023SJGLX136Y)the Key R&D Special Program of Henan Province(Grant No.241111242000)the Program for Science&Technology Innovation Talents in Universities of Henan Province(Grant No.25HASTIT005)the Training Plan for Young Backbone Teachers of Zhengzhou University(Grant No.2023ZDGGJS017)the Joint Research Project of Puyang ShengtongJuyuan New Materials Co.Ltd.(Grant No.20230128A)。
文摘Wide-bandgap mixed-halide perovskites,particularly CsPbIBr_(2),hold great promise for multi-junction solar cells due to their well-matched bandgap and all-inorganic material system.However,their inherent susceptibility to light-induced phase segregation(LIPS)limits efficiency and stability.In this work,we investigate the effect of three organic additives-4-cyclopentene-1,3-dione(CPD),maleimide(HPD),and 3,4-dibromo-1H-pyrrole-2,5(2H,5H)-dione(BrPD)-on LIPS in wide-bandgap CsPbIBr_(2)perovskite films.The additives form various chemical interactions,including coordination bonds,hydrogen bonds,and ionic bonds,with I^(-)and undercoordinated Pb^(2+)ions,among which BrPD has the strongest interaction.This interaction regulates crystallization and improves film morphology.The BrPD-modified films have the largest grain size and the highest light stability,suppressing LIPS,enhancing carrier transfer,and improving device performance.BrPD-modified CsPbIBr_(2)-based solar cells achieve a power conversion efficiency(PCE)of 11.34%,outperforming the control(8.96%)and other additives.Moreover,BrPDmodified devices show excellent stability,retaining 94%of their initial PCE after 60 min of continuous light exposure.This work highlights the potential of strategically selected organic additives to enhance the stability and performance of perovskite solar cells,offering valuable insights for the design of high-efficiency and long-lasting perovskite-based optoelectronic devices.
基金Shaanxi Province Qin Chuangyuan“Scientist+Engineer”Team Construction Project(2022KXJ-071)2022 Qin Chuangyuan Achievement Transformation Incubation Capacity Improvement Project(2022JH-ZHFHTS-0012)+8 种基金Shaanxi Province Key Research and Development Plan-“Two Chains”Integration Key Project-Qin Chuangyuan General Window Industrial Cluster Project(2023QCY-LL-02)Xixian New Area Science and Technology Plan(2022-YXYJ-003,2022-XXCY-010)2024 Scientific Research Project of Shaanxi National Defense Industry Vocational and Technical College(Gfy24-07)Shaanxi Vocational and Technical Education Association 2024 Vocational Education Teaching Reform Research Topic(2024SZX354)National Natural Science Foundation of China(U24A20115)2024 Shaanxi Provincial Education Department Service Local Special Scientific Research Program Project-Industrialization Cultivation Project(24JC005,24JC063)Shaanxi Province“14th Five-Year Plan”Education Science Plan,2024 Project(SGH24Y3181)National Key Research and Development Program of China(2023YFB4606400)Longmen Laboratory Frontier Exploration Topics Project(LMQYTSKT003)。
文摘A dual-phase synergistic enhancement method was adopted to strengthen the Al-Mn-Mg-Sc-Zr alloy fabricated by laser powder bed fusion(LPBF)by leveraging the unique advantages of Er and TiB_(2).Spherical powders of 0.5wt%Er-1wt%TiB_(2)/Al-Mn-Mg-Sc-Zr nanocomposite were prepared using vacuum homogenization technique,and the density of samples prepared through the LPBF process reached 99.8%.The strengthening and toughening mechanisms of Er-TiB_(2)were investigated.The results show that Al_(3)Er diffraction peaks are detected by X-ray diffraction analysis,and texture strength decreases according to electron backscatter diffraction results.The added Er and TiB_(2)nano-reinforcing phases act as heterogeneous nucleation sites during the LPBF forming process,hindering grain growth and effectively refining the grains.After incorporating the Er-TiB_(2)dual-phase nano-reinforcing phases,the tensile strength and elongation at break of the LPBF-deposited samples reach 550 MPa and 18.7%,which are 13.4%and 26.4%higher than those of the matrix material,respectively.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.U25A20232,52325208,52173217,52202128)the Interdisciplinary Research Project for Young Teachers of USTB(Grant No.FRF-IDRY24-002)。
文摘As electronic technology continues to evolve towards miniaturization and integration,the demand for micro-refrigeration technology in microelectronic systems is increasing.Ferroelectric(FE)refrigeration technology based on the electrocaloric effect(ECE)has emerged as a highly promising candidate in this field,due to its advantages of high energy efficiency,simple structure,easy miniaturization,low cost,and environmental friendliness.The EC performance of FE materials essentially depends on the phase transition features under the coupled electric and thermal fields,making the E–T phase diagram a core tool for decoding the underlying mechanism of ECE.This paper reviews the development of EC materials,focusing on the comprehensive study of E–T phase diagrams.By correlating the microscopic phase structure of FE materials with the macroscopic physical properties,it clarifies the manipulation mechanism for enhanced ECE performance,providing theoretical support for the targeted design of high-performance EC materials.In the future,the introduction of data-driven methods is expected to enable the high-throughput construction of FE phase diagrams,thereby accelerating the optimization of high-performance EC materials and promoting the practical application of FE refrigeration technology.
基金supported by National Natural Science Foundation of China(No.22376053)supported by the Natural Science Foundation of Henan Province,China(No.242300421034)Henan Key Scientific Research Programs to Universities and Colleges(No.22ZX003)。
文摘The coating material is considered as the key of solid-phase microextraction(SPME)due to the fact that which has much effect on the selectivity and sensitivity of the analytical method.Herein,the porous hollow carbon nanospheres(PHCNs)were synthesized by selectively removing the interior part of solid inhomogeneous nanospheres with acetone.Using PHCNs as new coating material,a SPME fiber was prepared.To the best of our knowledge,PHCNs was utilized as a SPME fiber coating for the first time.The fiber coating material PHCNs demonstrated excellent thermal stability(>800℃)and long usage lifespan(≥60 times).A headspace SPME(HS-SPME)was established to non-contact extract and enrich polycyclic aromatic hydrocarbons(PAHs)prior to gas chromatography-flame ionization detector(GC-FID)analysis.The HS-SPME not only can eliminate non-volatile interferences from matrix,but also be able to protect fiber coating and prolong lifespan of fiber prober.The linearity in the linear range of 0.01-30 ng/m L and limits of detection from 0.003 ng/mL to 0.006 ng/mL were obtained by HS-SPME-GC-FID with PHCNs as fiber coating.The enrichment factors were calculated as 5420-9211 compared with conventional direct introduce analysis.The spiked recoveries of real samples including campus lake water and lime tree honey were obtained from 80.93%to 118.0%with relative standard deviation no higher than 10.6%.The π-π stacking interaction,CH/π interaction,and unique built-in cavities significantly enhance the extraction performance of PHCNs coating fiber to PAHs.This work demonstrated that the PHCNs as fiber coating materials present good application prospects for the extraction and enrichment of trace PAHs from complex matrixes.
基金J.YANG was supported by funding from the National Natural Science Foundation of China(Grant Nos.42475022,42261144671)the National Key R&D Program of China(Project No.2024YFC3013100)+2 种基金the Fundamental Research Funds for the Central UniversitiesM.LU was supported by the Otto Poon Centre of Climate Resilience and Sustainability at HKUST and the Hong Kong Research Grant Committee(Project No.16300424)Data processing and storage were supported by the National Key Scientific and Technological Infrastructure project“Earth System Numerical Simulation Facility”(EarthLab).
文摘Precise forecasts of wildfire danger are crucial for proactive fuel management and emergency responses,yet they pose a challenge at the subseasonal scale due to limitations in prediction capabilities and a gap between forecast outputs and the needs of decision-makers.This study introduces an innovative hybrid modeling framework that integrates artificial intelligence(AI)with climate dynamic prediction systems to accurately forecast High Fire-Danger Days(HFDDs)for the following month.These HFDDs are derived from historical satellite fire data and the optimum fire danger index,with a particular focus on Southwest China as a case study.The AI module,based on the ResNet-18 neural network model,integrates observational and physically constrained analysis to establish links between HFDDs and optimal predictors of atmospheric circulation from both the concurrent and preceding months.Leveraging climate dynamical forecasting,this hybrid model provides more reliable deterministic predictions for monthly HFDDs than conventional methods that rely solely on terrestrial variables such as precipitation.More importantly,the integration of dynamical ensemble prediction enhances the model’s capability for skillful probabilistic predictions of HFDDs,facilitating the creation of customized fire danger outlooks and emergency action maps tailored to stakeholders’needs.The model’s added economic value was also evaluated,demonstrating its potential to improve decision-making in disaster management and bridge the“last-mile gap”in climate service delivery.This work contributes to the Seamless Prediction and Services for Sustainable Natural and Built Environment(SEPRESS)Program(2025–32),under the United Nations Educational Scientific and Cultural Organization(UNESCO)International Decade of Sciences for Sustainable Development(2024–33).
