The transition phase of GaAs from the zincblende （ZB） structure to the rocksalt （RS） structure is investigated by ab initio plane-wave pseudopotential density functional theory method, and the thermodynamic proper...The transition phase of GaAs from the zincblende （ZB） structure to the rocksalt （RS） structure is investigated by ab initio plane-wave pseudopotential density functional theory method, and the thermodynamic properties of the ZB and RS structures are obtained through the quasi-harmonic Debye model. It is found that the transition from the ZB structure to the RS structure occurs at the pressure of about 16.3 GPa, this fact is well consistent with the experimental data and other theoretical results. The dependences of the relative volume V/V0 on the pressure P, the Debye temperature Θ and specific heat Cv on the pressure P, as well as the specific heat CV on the temperature T are also obtained successfully.展开更多
The plastic deformation of semiconductors,a process critical to their mechanical and electronic properties,involves various mechanisms such as dislocation motion and phase transition.Here,we systematically examined th...The plastic deformation of semiconductors,a process critical to their mechanical and electronic properties,involves various mechanisms such as dislocation motion and phase transition.Here,we systematically examined the temperature-dependent Peierls stress for 30°and 90°partial dislocations in cadmium telluride(CdTe),using a combination of molecular statics and molecular dynamics simulations with a machine-learning force field,as well as density functional theory simulations.Our findings reveal that the 0 K Peierls stresses for these partial dislocations in CdTe are relatively low,ranging from 0.52 GPa to 1.46 GPa,due to its significant ionic bonding characteristics.Notably,in the CdTe system containing either a 30°Cd-core or 90°Te-core partial dislocation,a phase transition from the zinc-blende phase to theβ-Sn-like phase is favored over dislocation motion.This suggests a competitive relationship between these two mechanisms,driven by the bonding characteristics within the dislocation core and the relatively low phase transition stress of∼1.00 GPa.Furthermore,we observed a general trend wherein the Peierls stress for partial dislocations in CdTe exhibits a temperature dependence,which decreases with increasing temperature,becoming lower than the phase transition stress at elevated temperatures.Consequently,the dominant deformation mechanism in CdTe shifts from solid-state phase transition at low temperatures to dislocation motion at high temperatures.This investigation uncovers a compelling interplay between dislocation motion and phase transition in the plastic deformation of CdTe,offering profound insights into the mechanical behavior and electronic performance of CdTe and other II-VI semiconductors.展开更多
Layered transition metal oxides have emerged as promising cathode materials for sodium ion batteries.However,irreversible phase transitions cause structural distortion and cation rearrangement,leading to sluggish Na+d...Layered transition metal oxides have emerged as promising cathode materials for sodium ion batteries.However,irreversible phase transitions cause structural distortion and cation rearrangement,leading to sluggish Na+dynamics and rapid capacity decay.In this study,we propose a medium-entropy cathode by simultaneously introducing Fe,Mg,and Li dopants into a typical P2-type Na_(0.75)Ni_(0.25)Mn_(0.75)O_(2)cathode.The modified Na_(0.75)Ni_(0.2125)Mn_(0.6375)Fe_(0.05)Mg_(0.05)Li_(0.05)O_(2)cathode predominantly exhibits a main P2 phase(93.5%)with a minor O3 phase(6.5%).Through spectroscopy techniques and electrochemical investigations,we elucidate the redox mechanisms of Ni^(2+/3+/4+),Mn^(3+/4+),Fe^(3+/4+),and O_(2)-/O_(2)^(n-)during charging/discharging.The medium-entropy doping mitigates the detrimental P2-O_(2)phase transition at high-voltage,replacing it with a moderate and reversible structural evolution(P2-OP4),thereby enhancing structural stability.Consequently,the modified cathode exhibits a remarkable rate capacity of 108.4 mAh·g^(-1)at 10C,with a capacity retention of 99.0%after 200 cycles at 1C,82.5%after 500 cycles at 5C,and 76.7%after 600 cycles at 10C.Furthermore,it also demonstrates superior electrochemical performance at high cutoff voltage of 4.5 V and extreme temperature(55 and 0℃).This work offers solutions to critical challenges in sodium ion batteries cathode materials.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
A longstanding discrepancy between theoretical predictions and experimental observations on the highpressurestructural transformations of lanthanum mononitride(LaN)has posed challenges for understandingthe behavior of...A longstanding discrepancy between theoretical predictions and experimental observations on the highpressurestructural transformations of lanthanum mononitride(LaN)has posed challenges for understandingthe behavior of heavy transition metal mononitrides.Here,we systematically investigate the structural evolutionof LaN under high pressure using first-principles calculations combined with angle-dispersive synchrotron X-raydiffraction,identifying the phase transition sequence and corresponding phase boundaries.Analyses of energetics,kinetic barriers,and lattice dynamics reveal distinct mechanisms driving these transitions.These results clarifythe structural stability of LaN and offer guidance for studying other heavy transition metal mononitrides withcomplex electronic behavior under extreme conditions.展开更多
Multiple switchable physical channels within one material or device,encompassing optical,electrical,thermal,and mechanical pathways,can enable multifunctionality in mechanical-thermal-opto-electronic applications.Achi...Multiple switchable physical channels within one material or device,encompassing optical,electrical,thermal,and mechanical pathways,can enable multifunctionality in mechanical-thermal-opto-electronic applications.Achieving integrated encryption and enhanced performance in storage and sensing presents a formidable challenge in the synthesis and functionality of new materials.In an effort to overcome the complexities associated with these multiple physical functions,this study investigates the large-size crystal of DPACdCl_(4)(DPA=diisopropylammonium),revealing significant features in rare multi-channel switches.This compound demonstrates the ability to switch between"OFF/0"and"ON/1"states in the mechanical-thermal-opto-electronic channels.Consequently,DPACd Cl_(4)possesses four switchable physical channels,characterized by a higher phase transition temperature of 440.7 K and a competitive piezo-electric coefficient of 46 pC/N.Furthermore,solid-state NMR analysis indicates that thermally activated molecular vibrations significantly contribute to its multifunctional switching capabilities.展开更多
During strong unsteady flow processes such as cavitation initiation and collapse,the volume changes generated by the materials transformation of cavitation phase transition seriously lag behind the volume evolution fo...During strong unsteady flow processes such as cavitation initiation and collapse,the volume changes generated by the materials transformation of cavitation phase transition seriously lag behind the volume evolution formed by the flow process.The phase transition and hydrodynamics are in a non-equilibrium state.A cavitation model that can describe such non-equilibrium phenomena is needed in numerical simulations of cavitation flow.The paper starts from the molecular dynamics’principle of phase change of matter,and based on the Maxwell velocity distribution form of molecular thermal motion,elaborates on the formation process of Hertz Knudsen formula for material exchange at the interface between liquid and vapor.On this basis,using the evolution equation of gas nucleus number density in water and the compressible state equation of vapor,a non-equilibrium cavitation model for phase transition and hydrodynamics is established.The simulation results of a vapor bubble collapse process in the non-equilibrium cavitation model show different behavior from the simulation results of the equilibrium cavitation model.The simulation results of the equilibrium cavitation model show that the vapor bubble collapses once and completely disappear,while the simulation results of the non-equilibrium cavitation model show multiple collapses and rebound,which is agreement with the experimental results of the vapor bubble collapse.展开更多
The phase transition among different solid forms of active pharmaceutical ingredients can significantly influence their physicochemical properties,potentially leading to clinical safety risks.However,phase transition ...The phase transition among different solid forms of active pharmaceutical ingredients can significantly influence their physicochemical properties,potentially leading to clinical safety risks.However,phase transition mechanisms remain under explored,especially in multi-component drugs.Here we report a novel ciprofloxacin-diclofenac salt system and investigate phase transitions among its anhydrate,dihydrate,and methanol solvate forms.The study focused on the influence of water activity and solvent vapor conditions,elucidating the role of vip molecules in driving these transitions.These findings offer new insights into polymorphic phase transitions,advancing our understanding of stability and performance in pharmaceutical formulations.展开更多
Organic ferroelastics with metal free features and intrinsically light weight are highly desirable for future applications in flexible,smart and biocompatible devices.However,organoferroelastics with plastic phase tra...Organic ferroelastics with metal free features and intrinsically light weight are highly desirable for future applications in flexible,smart and biocompatible devices.However,organoferroelastics with plastic phase transition have rarely been reported yet.Herein,we discovered ferroelasticity in a pair of organic enantiomers,(1S and/or 1R)-2,10-camphorsultam(S-and R-CPS),which undergoes a high-T_(c)plastic phase transition.Both large entropies change of∼45 J mol^(-1)K^(-1)and evidently ductile deformation process confirm the plastic phase feature.Strip-like ferroelastic domain patterns and bidirectional domain movements have been observed via polarized light microscopy and nanoindentation technique,respectively.This work highlights the discovery of organic ferroelastic combining the features of enantiomers and plastic phase transition,which contributes insights into exploration of organic multifunctional materials.展开更多
The deployment of non-precious metal catalysts for the production of COx-free hydrogen via the ammonia decomposition reaction(ADR)presents a promising yet great challenge.In the present study,two crystal structures of...The deployment of non-precious metal catalysts for the production of COx-free hydrogen via the ammonia decomposition reaction(ADR)presents a promising yet great challenge.In the present study,two crystal structures of α-MoC and β-Mo_(2)C catalysts with different Mo/C ratios were synthesized,and their ammonia decomposition performance as well as structural evolution in ADR was investigated.The β-Mo_(2)C catalyst,characterized by a higher Mo/C ratio,demonstrated a remarkable turnover frequency of 1.3 s^(-1),which is over tenfold higher than that ofα-MoC(0.1 s^(-1)).An increase in the Mo/C ratio of molybdenum carbide revealed a direct correlation between the surface Mo/C ratio and the hydrogen yield.The transient response surface reaction indicated that the combination of N*and N*derived from NH_(3) dissociation represents the rate-determining step in the ADR,andβ-Mo2C exhibited exceptional proficiency in facilitating this pivotal step.Concurrently,the accumulation of N*species on the carbide surface could induce the phase transition of molybdenum carbide to nitride,which follows a topological transformation.It is discovered that such phase evolution was affected by the Mo-C surface and reaction temperature simultaneously.When the kinetics of combination of N*was accelerated by rising temperatures and its accumulation on the carbide surface was mitigated,β-Mo_(2)C maintained its carbide phase,preventing nitridation during the ADR at 810℃.Our results contribute to an in-depth understanding of the molybdenum carbides’catalytic properties in ADR and highlight the nature of the carbide-nitride phase transition in the reaction.展开更多
It is a key challenge to prepare two-dimensional diamond(2D-diamond).Herein,we develop a method for synthesizing 2D-diamond by depositing monodisperse tantalum(Ta)atoms onto graphene substrates using a hot-filament ch...It is a key challenge to prepare two-dimensional diamond(2D-diamond).Herein,we develop a method for synthesizing 2D-diamond by depositing monodisperse tantalum(Ta)atoms onto graphene substrates using a hot-filament chemical vapor deposition setup,followed by annealing treatment under different temperatures at ambient pressure.The results indicate that when the annealing temperature increases from 700℃ to 1000℃,the size of the 2D-diamond found in the samples gradually increases from close to 20 nm to around 30 nm.Meanwhile,the size and number of amorphous carbon spheres and Ta-containing compounds between the graphene layers gradually increase.As the annealing temperature continues to rise to 1100℃,a significant aggregation of Ta-containing compounds is observed in the samples,with no diamond structure detected.This further confirms that monodisperse Ta atoms play a key role in graphene phase transition into 2D-diamond.This study provides a novel method for the ambient-pressure phase transition of graphene into 2D-diamond.展开更多
The slow phase transition from formⅡto formⅠhas always been an important factor that restricts the processing and application of polybutene-1(PB-1).After extensive efforts,a set of effective methods for promoting th...The slow phase transition from formⅡto formⅠhas always been an important factor that restricts the processing and application of polybutene-1(PB-1).After extensive efforts,a set of effective methods for promoting the phase transition rate in PB-1 was established by adjusting the crystallization,nucleation,and growth temperatures.Nevertheless,low-molecular-weight PB-1(LMWPB-1)faces challenges because this method requires a low crystallization temperature,which is difficult to achieve during extrusion processing.In this study,we attempted to increase the phase transition rate in PB-1 by changing the annealing temperature after processing rather than the crystallization temperature in the classical scheme.The results indicated that regardless of low-or high-molecular-weight PB-1,repeated annealing between 0 and 90℃could also promote formⅡto formⅠphase transition.The initial content of formⅠincreased with the heating and cooling cycles.The half-time of the phase transition(t_(1/2))was also shortened after heating/cooling.After 100 heating/cooling cycles,t_(1/2) was reduced to one-quarter of that without annealing,which had almost the same effect as the crystallization temperature at 25℃in promoting the phase transition.This study indicates that annealing after processing is also an important factor affecting the phase transition of PB-1,and should receive sufficient attention.展开更多
It has been argued that the human brain,as an information-processing machine,operates near a phase transition point in a non-equilibrium state,where it violates detailed balance leading to entropy production.Thus,the ...It has been argued that the human brain,as an information-processing machine,operates near a phase transition point in a non-equilibrium state,where it violates detailed balance leading to entropy production.Thus,the assessment of irreversibility in brain networks can provide valuable insights into their non-equilibrium properties.In this study,we utilized an open-source whole-brain functional magnetic resonance imaging(fMRI)dataset from both resting and task states to evaluate the irreversibility of large-scale human brain networks.Our analysis revealed that the brain networks exhibited significant irreversibility,violating detailed balance,and generating entropy.Notably,both physical and cognitive tasks increased the extent of this violation compared to the resting state.Regardless of the state(rest or task),interactions between pairs of brain regions were the primary contributors to this irreversibility.Moreover,we observed that as global synchrony increased within brain networks,so did irreversibility.The first derivative of irreversibility with respect to synchronization peaked near the phase transition point,characterized by the moderate mean synchronization and maximized synchronization entropy of blood oxygenation level-dependent(BOLD)signals.These findings deepen our understanding of the non-equilibrium dynamics of large-scale brain networks,particularly in relation to their phase transition behaviors,and may have potential clinical applications for brain disorders.展开更多
Vanadium phosphorus oxide(VPO)catalyst is a promising candidate for the condensation reaction of formaldehyde(FA)and acetic acid(HAc)to produce acrylic acid(AA).However,the complexity of the active phases and their dy...Vanadium phosphorus oxide(VPO)catalyst is a promising candidate for the condensation reaction of formaldehyde(FA)and acetic acid(HAc)to produce acrylic acid(AA).However,the complexity of the active phases and their dynamic interconversion under redox conditions has led to controversies regarding the actual active phase in this reaction.To address this,this study systematically investigates the phase transition and underlying mechanism of VPO catalysts under reaction conditions.X-ray diffraction(XRD)patterns,Raman spectra,transmission electron microscopy images and X-ray photoelectron spectroscopy collectively demonstrated that the V^(4+)phase(VO)_(2)P_(2)O_(7)retained the bulk phase structure throughout the reaction,with only minor surface phase transition observed.In contrast,the V^(5+)phase underwent reduction to other phases in both bulk and surface regions.Specifically,theδ-VOPO_(4)phase rapidly transformed into theαII-VOPO_(4)phase,which could reversibly convert into the R1-VOHPO_(4)phase(V^(4+)).Controlled variable experiments,H_(2)-temperature programmed reduction and in-situ XRD experiments in a hydrogen atmosphere further demonstrated that these phase transitions were primarily attributed to the loss of lattice oxygen.The presence of V^(4+)phase in VPO catalysts enhanced the selectivity of acrylic acid,while the existence of V^(5+)phase promoted the activation of acetic acid.This work elucidates the redox-driven phase evolution of VPO catalysts and offers valuable insights for designing efficient catalysts for FA-HAc cross-condensation by balancing phase stability and activity.展开更多
The stretching-induced phase transition of biodegradable poly(butylene succinate)(PBS)was explored using a combination of mechanical testing and in situ wide angle X-ray diffraction characterization.The phase transiti...The stretching-induced phase transition of biodegradable poly(butylene succinate)(PBS)was explored using a combination of mechanical testing and in situ wide angle X-ray diffraction characterization.The phase transition fromαphase toβphase can be effectively triggered by severe stretching,in which the threshold strain is dependent on the PBS crystallites.Interestingly,thisα-βphase transition can be reversed immediately once mechanical stretching begins to be released.It should be pointed out that the finish ofβ-αphase transition reversed,corresponding to the disappearance of the generatedβphase,does not necessarily need the external stretching to completely release.For the relaxation-reversed phase transition,the evolution of the normalizedβ-phase fraction exhibited a similar correlation with the stress released.It was indicated that the decay kinetics followed a stretching-dominant mechanism,and the amount ofβphase generated just prior to relaxation had a negligible influence on the reversed phase transition.展开更多
Figure 6(a)in the paper[Chin.Phys.B 33074203(2024)]was incorrect due to editorial oversight.The correct figure is provided.This modification does not affect the result presented in the paper.
Based on the principles of thermodynamics, we elucidate the fundamental reasons behind the hysteresis of spontaneous polarization in ferroelectric materials during heating and cooling processes. By utilizing the effec...Based on the principles of thermodynamics, we elucidate the fundamental reasons behind the hysteresis of spontaneous polarization in ferroelectric materials during heating and cooling processes. By utilizing the effective Hamiltonian method in conjuction with the phase-field model, we have successfully reproduced the thermal hysteresis observed in ferroelectric materials during phase transitions. The computational results regarding the electrocaloric effect from these two different computational scales closely align with experimental measurements. Furthermore, we analyze how the first-order ferroelectric phase transition gradually diminishes with an increasing applied electric field, exhibiting characteristics of second-order-like phase transition. By employing the characteristic parameters of thermal hysteresis, we have established a pathway for calculations across different computational scales, thereby providing theoretical support for further investigations into the properties of ferroelectric materials through concurrent multiscale simulations.展开更多
P2-type layered oxide cathode materials have attracted extensive attention due to their simple preparation,high specific capacity,adjustable voltage range,and high packing density.However,the harmful phase transitions...P2-type layered oxide cathode materials have attracted extensive attention due to their simple preparation,high specific capacity,adjustable voltage range,and high packing density.However,the harmful phase transitions that occur at high voltage severely limit their practical application.Herein,a novel high-valence tungsten doped P2-Na_(0.67)Ni_(0.33)Mn_(0.67)O_(2)cathode material was prepared using the sol–gel method.Through diffusion kinetics analysis and in situ X-ray diffraction(in situ XRD),it has been proven that W^(6+)not only enhances the Na^(+)diffusion coefficient but also reduces the P2–O2 phase transition.The optimized NNMO-W1%delivers a high discharge specific capacity of 163 mAh·g^(-1)at 0.1C,and the capacity retention rate is as high as 77.6%after 1000 cycles at 10C.This is mainly due to that W^(6+)enters the lattice,optimizing the arrangement of primary particles.This work sheds light on the design and construction of high-performance layered oxides cathode materials.展开更多
Thermoelectric coolers utilizing the Peltier effect have dominated the field of solid-state cooling but their efficiency is hindered by material limitations.Alternative routes based on the Thomson and Nernst effects o...Thermoelectric coolers utilizing the Peltier effect have dominated the field of solid-state cooling but their efficiency is hindered by material limitations.Alternative routes based on the Thomson and Nernst effects offer new possibilities.Here,we present a comprehensive investigation of the thermoelectric properties of 1T-TiSe_(2),focusing on these effects around the charge density wave transition(≈200 K).The abrupt Fermi surface reconstruction associated with this transition leads to an exceptional peak in the Thomson coefficient of 450μVK^(-1) at 184 K,surpassing the Seebeck coefficient.Furthermore,1T-TiSe_(2) exhibits a remarkably broad temperature range(170-400 K)with a Thomson coefficient exceeding 190μV K^(-1),a characteristic highly desirable for the development of practical Thomson coolers with extended operational ranges.Additionally,the Nernst coefficient exhibits an unusual temperature dependence,increasing with temperature in the normal phase,which we attribute to bipolar conduction effects.The combination of solid-solid pure electronic phase transition to a semimetallic phase with bipolar transport is identified as responsible for the unusual Nernst trend and the unusually large Thomson coefficient over a broad temperature range.展开更多
We investigate the localization and topological properties of the Haldane model under the influence of random flux and Anderson disorder. Our localization analysis reveals that random flux induces a transition from in...We investigate the localization and topological properties of the Haldane model under the influence of random flux and Anderson disorder. Our localization analysis reveals that random flux induces a transition from insulating to metallic states, while Anderson localization only arises under the modulation of Anderson disorder. By employing real-space topological invariant methods, we demonstrates that the system undergoes topological phase transitions under different disorder manipulations, whereas random flux modulation uniquely induces topological Anderson insulator phases, with the potential to generate states with opposite Chern numbers. These findings highlight the distinct roles of disorder in shaping the interplay between topology and localization, providing insights into stabilizing topological states and designing robust topological quantum materials.展开更多
基金Project supported by the National Natural Science Foundation of China （Grant No 10576020） and by the SRF for R0CS of SEM of China （Grant No 2004176-6-4）.
文摘The transition phase of GaAs from the zincblende （ZB） structure to the rocksalt （RS） structure is investigated by ab initio plane-wave pseudopotential density functional theory method, and the thermodynamic properties of the ZB and RS structures are obtained through the quasi-harmonic Debye model. It is found that the transition from the ZB structure to the RS structure occurs at the pressure of about 16.3 GPa, this fact is well consistent with the experimental data and other theoretical results. The dependences of the relative volume V/V0 on the pressure P, the Debye temperature Θ and specific heat Cv on the pressure P, as well as the specific heat CV on the temperature T are also obtained successfully.
基金supported by the National Science Foundation(No.CMMI-2019459).
文摘The plastic deformation of semiconductors,a process critical to their mechanical and electronic properties,involves various mechanisms such as dislocation motion and phase transition.Here,we systematically examined the temperature-dependent Peierls stress for 30°and 90°partial dislocations in cadmium telluride(CdTe),using a combination of molecular statics and molecular dynamics simulations with a machine-learning force field,as well as density functional theory simulations.Our findings reveal that the 0 K Peierls stresses for these partial dislocations in CdTe are relatively low,ranging from 0.52 GPa to 1.46 GPa,due to its significant ionic bonding characteristics.Notably,in the CdTe system containing either a 30°Cd-core or 90°Te-core partial dislocation,a phase transition from the zinc-blende phase to theβ-Sn-like phase is favored over dislocation motion.This suggests a competitive relationship between these two mechanisms,driven by the bonding characteristics within the dislocation core and the relatively low phase transition stress of∼1.00 GPa.Furthermore,we observed a general trend wherein the Peierls stress for partial dislocations in CdTe exhibits a temperature dependence,which decreases with increasing temperature,becoming lower than the phase transition stress at elevated temperatures.Consequently,the dominant deformation mechanism in CdTe shifts from solid-state phase transition at low temperatures to dislocation motion at high temperatures.This investigation uncovers a compelling interplay between dislocation motion and phase transition in the plastic deformation of CdTe,offering profound insights into the mechanical behavior and electronic performance of CdTe and other II-VI semiconductors.
基金supported by the National Natural Science Foundation of China(No.21805018)by Sichuan Science and Technology Program(Nos.2022ZHCG0018,2023NSFSC0117 and 2023ZHCG0060)Yibin Science and Technology Program(No.2022JB005)and China Postdoctoral Science Foundation(No.2022M722704).
文摘Layered transition metal oxides have emerged as promising cathode materials for sodium ion batteries.However,irreversible phase transitions cause structural distortion and cation rearrangement,leading to sluggish Na+dynamics and rapid capacity decay.In this study,we propose a medium-entropy cathode by simultaneously introducing Fe,Mg,and Li dopants into a typical P2-type Na_(0.75)Ni_(0.25)Mn_(0.75)O_(2)cathode.The modified Na_(0.75)Ni_(0.2125)Mn_(0.6375)Fe_(0.05)Mg_(0.05)Li_(0.05)O_(2)cathode predominantly exhibits a main P2 phase(93.5%)with a minor O3 phase(6.5%).Through spectroscopy techniques and electrochemical investigations,we elucidate the redox mechanisms of Ni^(2+/3+/4+),Mn^(3+/4+),Fe^(3+/4+),and O_(2)-/O_(2)^(n-)during charging/discharging.The medium-entropy doping mitigates the detrimental P2-O_(2)phase transition at high-voltage,replacing it with a moderate and reversible structural evolution(P2-OP4),thereby enhancing structural stability.Consequently,the modified cathode exhibits a remarkable rate capacity of 108.4 mAh·g^(-1)at 10C,with a capacity retention of 99.0%after 200 cycles at 1C,82.5%after 500 cycles at 5C,and 76.7%after 600 cycles at 10C.Furthermore,it also demonstrates superior electrochemical performance at high cutoff voltage of 4.5 V and extreme temperature(55 and 0℃).This work offers solutions to critical challenges in sodium ion batteries cathode materials.
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.
基金supported by the Natural Science Foundation of China(Grant Nos.T2325013,12474004,and 52288102)the National Key Research and Development Program of China(Grant No.2021YFA1400503)the Program for Jilin University Science and Technology Innovative Research Team。
文摘A longstanding discrepancy between theoretical predictions and experimental observations on the highpressurestructural transformations of lanthanum mononitride(LaN)has posed challenges for understandingthe behavior of heavy transition metal mononitrides.Here,we systematically investigate the structural evolutionof LaN under high pressure using first-principles calculations combined with angle-dispersive synchrotron X-raydiffraction,identifying the phase transition sequence and corresponding phase boundaries.Analyses of energetics,kinetic barriers,and lattice dynamics reveal distinct mechanisms driving these transitions.These results clarifythe structural stability of LaN and offer guidance for studying other heavy transition metal mononitrides withcomplex electronic behavior under extreme conditions.
基金financial supported by National Natural Science Foundation of China(No.52303256)Natural Science Foundation of Zhejiang Province(No.LQ23B040004)Jinhua Industrial Major Project(No.2022-1-043)。
文摘Multiple switchable physical channels within one material or device,encompassing optical,electrical,thermal,and mechanical pathways,can enable multifunctionality in mechanical-thermal-opto-electronic applications.Achieving integrated encryption and enhanced performance in storage and sensing presents a formidable challenge in the synthesis and functionality of new materials.In an effort to overcome the complexities associated with these multiple physical functions,this study investigates the large-size crystal of DPACdCl_(4)(DPA=diisopropylammonium),revealing significant features in rare multi-channel switches.This compound demonstrates the ability to switch between"OFF/0"and"ON/1"states in the mechanical-thermal-opto-electronic channels.Consequently,DPACd Cl_(4)possesses four switchable physical channels,characterized by a higher phase transition temperature of 440.7 K and a competitive piezo-electric coefficient of 46 pC/N.Furthermore,solid-state NMR analysis indicates that thermally activated molecular vibrations significantly contribute to its multifunctional switching capabilities.
文摘During strong unsteady flow processes such as cavitation initiation and collapse,the volume changes generated by the materials transformation of cavitation phase transition seriously lag behind the volume evolution formed by the flow process.The phase transition and hydrodynamics are in a non-equilibrium state.A cavitation model that can describe such non-equilibrium phenomena is needed in numerical simulations of cavitation flow.The paper starts from the molecular dynamics’principle of phase change of matter,and based on the Maxwell velocity distribution form of molecular thermal motion,elaborates on the formation process of Hertz Knudsen formula for material exchange at the interface between liquid and vapor.On this basis,using the evolution equation of gas nucleus number density in water and the compressible state equation of vapor,a non-equilibrium cavitation model for phase transition and hydrodynamics is established.The simulation results of a vapor bubble collapse process in the non-equilibrium cavitation model show different behavior from the simulation results of the equilibrium cavitation model.The simulation results of the equilibrium cavitation model show that the vapor bubble collapses once and completely disappear,while the simulation results of the non-equilibrium cavitation model show multiple collapses and rebound,which is agreement with the experimental results of the vapor bubble collapse.
基金supported by the Young Scientists Promotion Fund of Natural Science Foundation of Guangdong Province(No.2023A1515030128)Natural Science Foundation of Guangdong Province(No.2024A1515011590)+1 种基金National Natural Science Foundation of China(No.81703438)CAMS Innovation Fund for Medical Sciences(No.2022-I2M-1-015).
文摘The phase transition among different solid forms of active pharmaceutical ingredients can significantly influence their physicochemical properties,potentially leading to clinical safety risks.However,phase transition mechanisms remain under explored,especially in multi-component drugs.Here we report a novel ciprofloxacin-diclofenac salt system and investigate phase transitions among its anhydrate,dihydrate,and methanol solvate forms.The study focused on the influence of water activity and solvent vapor conditions,elucidating the role of vip molecules in driving these transitions.These findings offer new insights into polymorphic phase transitions,advancing our understanding of stability and performance in pharmaceutical formulations.
基金supported by the National Natural Science Foundation of China(No.22271131)the Department of Science and Technology in Jiangxi Province(No.20225BCJ23029).
文摘Organic ferroelastics with metal free features and intrinsically light weight are highly desirable for future applications in flexible,smart and biocompatible devices.However,organoferroelastics with plastic phase transition have rarely been reported yet.Herein,we discovered ferroelasticity in a pair of organic enantiomers,(1S and/or 1R)-2,10-camphorsultam(S-and R-CPS),which undergoes a high-T_(c)plastic phase transition.Both large entropies change of∼45 J mol^(-1)K^(-1)and evidently ductile deformation process confirm the plastic phase feature.Strip-like ferroelastic domain patterns and bidirectional domain movements have been observed via polarized light microscopy and nanoindentation technique,respectively.This work highlights the discovery of organic ferroelastic combining the features of enantiomers and plastic phase transition,which contributes insights into exploration of organic multifunctional materials.
文摘The deployment of non-precious metal catalysts for the production of COx-free hydrogen via the ammonia decomposition reaction(ADR)presents a promising yet great challenge.In the present study,two crystal structures of α-MoC and β-Mo_(2)C catalysts with different Mo/C ratios were synthesized,and their ammonia decomposition performance as well as structural evolution in ADR was investigated.The β-Mo_(2)C catalyst,characterized by a higher Mo/C ratio,demonstrated a remarkable turnover frequency of 1.3 s^(-1),which is over tenfold higher than that ofα-MoC(0.1 s^(-1)).An increase in the Mo/C ratio of molybdenum carbide revealed a direct correlation between the surface Mo/C ratio and the hydrogen yield.The transient response surface reaction indicated that the combination of N*and N*derived from NH_(3) dissociation represents the rate-determining step in the ADR,andβ-Mo2C exhibited exceptional proficiency in facilitating this pivotal step.Concurrently,the accumulation of N*species on the carbide surface could induce the phase transition of molybdenum carbide to nitride,which follows a topological transformation.It is discovered that such phase evolution was affected by the Mo-C surface and reaction temperature simultaneously.When the kinetics of combination of N*was accelerated by rising temperatures and its accumulation on the carbide surface was mitigated,β-Mo_(2)C maintained its carbide phase,preventing nitridation during the ADR at 810℃.Our results contribute to an in-depth understanding of the molybdenum carbides’catalytic properties in ADR and highlight the nature of the carbide-nitride phase transition in the reaction.
基金supported by the Key Project of the National Natural Science Foundation of China(Grant No.U1809210)the International Science Technology Cooperation Program of China(Grant No.2014DFR51160)+3 种基金the One Belt and One Road International Cooperation Project from the Key Research and Development Program of Zhejiang Province,China(Grant No.2018C04021)the National Natural Science Foundation of China(Grant Nos.50972129,50602039,and 52102052)the Fund from Institute of Wenzhou,Zhejiang University(Grant Nos.XMGL-CX-202305 and XMGLKJZX-202307)the Project from Tanghe Scientific&Technology Company(Grant No.KYY-HX-20230024).
文摘It is a key challenge to prepare two-dimensional diamond(2D-diamond).Herein,we develop a method for synthesizing 2D-diamond by depositing monodisperse tantalum(Ta)atoms onto graphene substrates using a hot-filament chemical vapor deposition setup,followed by annealing treatment under different temperatures at ambient pressure.The results indicate that when the annealing temperature increases from 700℃ to 1000℃,the size of the 2D-diamond found in the samples gradually increases from close to 20 nm to around 30 nm.Meanwhile,the size and number of amorphous carbon spheres and Ta-containing compounds between the graphene layers gradually increase.As the annealing temperature continues to rise to 1100℃,a significant aggregation of Ta-containing compounds is observed in the samples,with no diamond structure detected.This further confirms that monodisperse Ta atoms play a key role in graphene phase transition into 2D-diamond.This study provides a novel method for the ambient-pressure phase transition of graphene into 2D-diamond.
基金financially supported by the National Natural Science Foundation of China(No.22175183)。
文摘The slow phase transition from formⅡto formⅠhas always been an important factor that restricts the processing and application of polybutene-1(PB-1).After extensive efforts,a set of effective methods for promoting the phase transition rate in PB-1 was established by adjusting the crystallization,nucleation,and growth temperatures.Nevertheless,low-molecular-weight PB-1(LMWPB-1)faces challenges because this method requires a low crystallization temperature,which is difficult to achieve during extrusion processing.In this study,we attempted to increase the phase transition rate in PB-1 by changing the annealing temperature after processing rather than the crystallization temperature in the classical scheme.The results indicated that regardless of low-or high-molecular-weight PB-1,repeated annealing between 0 and 90℃could also promote formⅡto formⅠphase transition.The initial content of formⅠincreased with the heating and cooling cycles.The half-time of the phase transition(t_(1/2))was also shortened after heating/cooling.After 100 heating/cooling cycles,t_(1/2) was reduced to one-quarter of that without annealing,which had almost the same effect as the crystallization temperature at 25℃in promoting the phase transition.This study indicates that annealing after processing is also an important factor affecting the phase transition of PB-1,and should receive sufficient attention.
基金supported by the Fundamental Research Funds for the Central Universities(Grant Nos.lzujbky-2021-62 and lzujbky-2024-jdzx06)the National Natural Science Foundation of China(Grant No.12247101)+1 种基金the Natural Science Foundation of Gansu Province,China(Grant Nos.22JR5RA389 and 23JRRA1740)the‘111 Center’Fund(Grant No.B20063).
文摘It has been argued that the human brain,as an information-processing machine,operates near a phase transition point in a non-equilibrium state,where it violates detailed balance leading to entropy production.Thus,the assessment of irreversibility in brain networks can provide valuable insights into their non-equilibrium properties.In this study,we utilized an open-source whole-brain functional magnetic resonance imaging(fMRI)dataset from both resting and task states to evaluate the irreversibility of large-scale human brain networks.Our analysis revealed that the brain networks exhibited significant irreversibility,violating detailed balance,and generating entropy.Notably,both physical and cognitive tasks increased the extent of this violation compared to the resting state.Regardless of the state(rest or task),interactions between pairs of brain regions were the primary contributors to this irreversibility.Moreover,we observed that as global synchrony increased within brain networks,so did irreversibility.The first derivative of irreversibility with respect to synchronization peaked near the phase transition point,characterized by the moderate mean synchronization and maximized synchronization entropy of blood oxygenation level-dependent(BOLD)signals.These findings deepen our understanding of the non-equilibrium dynamics of large-scale brain networks,particularly in relation to their phase transition behaviors,and may have potential clinical applications for brain disorders.
文摘Vanadium phosphorus oxide(VPO)catalyst is a promising candidate for the condensation reaction of formaldehyde(FA)and acetic acid(HAc)to produce acrylic acid(AA).However,the complexity of the active phases and their dynamic interconversion under redox conditions has led to controversies regarding the actual active phase in this reaction.To address this,this study systematically investigates the phase transition and underlying mechanism of VPO catalysts under reaction conditions.X-ray diffraction(XRD)patterns,Raman spectra,transmission electron microscopy images and X-ray photoelectron spectroscopy collectively demonstrated that the V^(4+)phase(VO)_(2)P_(2)O_(7)retained the bulk phase structure throughout the reaction,with only minor surface phase transition observed.In contrast,the V^(5+)phase underwent reduction to other phases in both bulk and surface regions.Specifically,theδ-VOPO_(4)phase rapidly transformed into theαII-VOPO_(4)phase,which could reversibly convert into the R1-VOHPO_(4)phase(V^(4+)).Controlled variable experiments,H_(2)-temperature programmed reduction and in-situ XRD experiments in a hydrogen atmosphere further demonstrated that these phase transitions were primarily attributed to the loss of lattice oxygen.The presence of V^(4+)phase in VPO catalysts enhanced the selectivity of acrylic acid,while the existence of V^(5+)phase promoted the activation of acetic acid.This work elucidates the redox-driven phase evolution of VPO catalysts and offers valuable insights for designing efficient catalysts for FA-HAc cross-condensation by balancing phase stability and activity.
基金supported by the National Natural Science Foundation of China(No.52273025).
文摘The stretching-induced phase transition of biodegradable poly(butylene succinate)(PBS)was explored using a combination of mechanical testing and in situ wide angle X-ray diffraction characterization.The phase transition fromαphase toβphase can be effectively triggered by severe stretching,in which the threshold strain is dependent on the PBS crystallites.Interestingly,thisα-βphase transition can be reversed immediately once mechanical stretching begins to be released.It should be pointed out that the finish ofβ-αphase transition reversed,corresponding to the disappearance of the generatedβphase,does not necessarily need the external stretching to completely release.For the relaxation-reversed phase transition,the evolution of the normalizedβ-phase fraction exhibited a similar correlation with the stress released.It was indicated that the decay kinetics followed a stretching-dominant mechanism,and the amount ofβphase generated just prior to relaxation had a negligible influence on the reversed phase transition.
文摘Figure 6(a)in the paper[Chin.Phys.B 33074203(2024)]was incorrect due to editorial oversight.The correct figure is provided.This modification does not affect the result presented in the paper.
基金Project supported financially by the National Natural Science Foundation of China (Grant No. 52372100)the National Key Research and Development Program of China (Grant No. 2019YFA0307900)。
文摘Based on the principles of thermodynamics, we elucidate the fundamental reasons behind the hysteresis of spontaneous polarization in ferroelectric materials during heating and cooling processes. By utilizing the effective Hamiltonian method in conjuction with the phase-field model, we have successfully reproduced the thermal hysteresis observed in ferroelectric materials during phase transitions. The computational results regarding the electrocaloric effect from these two different computational scales closely align with experimental measurements. Furthermore, we analyze how the first-order ferroelectric phase transition gradually diminishes with an increasing applied electric field, exhibiting characteristics of second-order-like phase transition. By employing the characteristic parameters of thermal hysteresis, we have established a pathway for calculations across different computational scales, thereby providing theoretical support for further investigations into the properties of ferroelectric materials through concurrent multiscale simulations.
基金supported by the National Natural Science Foundation of China Key Program(No.U22A20420)Changzhou Leading Innovative Talents Introduction and Cultivation Project(No.CQ20230109)the Key Project of Jiangsu Provincial Basic Research Program(No.BK20243032)。
文摘P2-type layered oxide cathode materials have attracted extensive attention due to their simple preparation,high specific capacity,adjustable voltage range,and high packing density.However,the harmful phase transitions that occur at high voltage severely limit their practical application.Herein,a novel high-valence tungsten doped P2-Na_(0.67)Ni_(0.33)Mn_(0.67)O_(2)cathode material was prepared using the sol–gel method.Through diffusion kinetics analysis and in situ X-ray diffraction(in situ XRD),it has been proven that W^(6+)not only enhances the Na^(+)diffusion coefficient but also reduces the P2–O2 phase transition.The optimized NNMO-W1%delivers a high discharge specific capacity of 163 mAh·g^(-1)at 0.1C,and the capacity retention rate is as high as 77.6%after 1000 cycles at 10C.This is mainly due to that W^(6+)enters the lattice,optimizing the arrangement of primary particles.This work sheds light on the design and construction of high-performance layered oxides cathode materials.
基金S.A.and M.Z.acknowledge support by NSF,grant number 2230352S.S.D.acknowledges support from the UVA Research Innovation AwardK.S.D.and D.L.work on TMDs has been supported by National Science Foundation Grant No.221949.
文摘Thermoelectric coolers utilizing the Peltier effect have dominated the field of solid-state cooling but their efficiency is hindered by material limitations.Alternative routes based on the Thomson and Nernst effects offer new possibilities.Here,we present a comprehensive investigation of the thermoelectric properties of 1T-TiSe_(2),focusing on these effects around the charge density wave transition(≈200 K).The abrupt Fermi surface reconstruction associated with this transition leads to an exceptional peak in the Thomson coefficient of 450μVK^(-1) at 184 K,surpassing the Seebeck coefficient.Furthermore,1T-TiSe_(2) exhibits a remarkably broad temperature range(170-400 K)with a Thomson coefficient exceeding 190μV K^(-1),a characteristic highly desirable for the development of practical Thomson coolers with extended operational ranges.Additionally,the Nernst coefficient exhibits an unusual temperature dependence,increasing with temperature in the normal phase,which we attribute to bipolar conduction effects.The combination of solid-solid pure electronic phase transition to a semimetallic phase with bipolar transport is identified as responsible for the unusual Nernst trend and the unusually large Thomson coefficient over a broad temperature range.
基金Project supported by the National Key Research and Development Program of China (Grant Nos. 2021YFA1400900, 2021YFA0718300, and 2021YFA1402100)the National Natural Science Foundation of China (Grant Nos. 12174461, 12234012, 12334012, and 52327808)。
文摘We investigate the localization and topological properties of the Haldane model under the influence of random flux and Anderson disorder. Our localization analysis reveals that random flux induces a transition from insulating to metallic states, while Anderson localization only arises under the modulation of Anderson disorder. By employing real-space topological invariant methods, we demonstrates that the system undergoes topological phase transitions under different disorder manipulations, whereas random flux modulation uniquely induces topological Anderson insulator phases, with the potential to generate states with opposite Chern numbers. These findings highlight the distinct roles of disorder in shaping the interplay between topology and localization, providing insights into stabilizing topological states and designing robust topological quantum materials.
