The martensitic transformation temperature is the basis for the application of shape memory alloys(SMAs),and the ability to quickly and accurately predict the transformation temperature of SMAs has very important prac...The martensitic transformation temperature is the basis for the application of shape memory alloys(SMAs),and the ability to quickly and accurately predict the transformation temperature of SMAs has very important practical significance.In this work,machine learning(ML)methods were utilized to accelerate the search for shape memory alloys with targeted properties(phase transition temperature).A group of component data was selected to design shape memory alloys using reverse design method from numerous unexplored data.Component modeling and feature modeling were used to predict the phase transition temperature of the shape memory alloys.The experimental results of the shape memory alloys were obtained to verify the effectiveness of the support vector regression(SVR)model.The results show that the machine learning model can obtain target materials more efficiently and pertinently,and realize the accurate and rapid design of shape memory alloys with specific target phase transition temperature.On this basis,the relationship between phase transition temperature and material descriptors is analyzed,and it is proved that the key factors affecting the phase transition temperature of shape memory alloys are based on the strength of the bond energy between atoms.This work provides new ideas for the controllable design and performance optimization of Cu-based shape memory alloys.展开更多
Post-heat treatment is commonly employed to improve the microstructural homogeneity and enhance the mechanical performances of the additively manufactured metallic materials.In this work,a ternary(NiTi)91Nb9(at.%)shap...Post-heat treatment is commonly employed to improve the microstructural homogeneity and enhance the mechanical performances of the additively manufactured metallic materials.In this work,a ternary(NiTi)91Nb9(at.%)shape memory alloy was produced by laser powder bed fusion(L-PBF)using pre-alloyed NiTi and elemental Nb powders.The effect of solution treatment on the microstructure,phase transformation behavior and mechanical/functional performances was investigated.The in-situ alloyed(NiTi)91Nb9 alloy exhibits a submicron cellular-dendritic structure surrounding the supersaturated B2-NiTi matrix.Upon high-temperature(1273 K)solution treatment,Nb-rich precipitates were precipitated from the supersaturated matrix.The fragmentation and spheroidization of the NiTi/Nb eutectics occurred during solution treatment,leading to a morphological transition from mesh-like into rod-like and sphere-like.Coarsening of theβ-Nb phases occurred with increasing holding time.The martensite transformation temperature increases after solution treatment,mainly attributed to:(i)reduced lattice distortion due to the Nb expulsion from the supersaturated B2-NiTi,and(ii)the Ti expulsion from theβ-Nb phases that lowers the ratio Ni/Ti in the B2-NiTi matrix,which resulted from the microstructure changes from non-equilibrium to equilibrium state.The thermal hysteresis of the solutionized alloys is around 145 K after 20%pre-deformation,which is comparable to the conventional NiTiNb alloys.A short-term solution treatment(i.e.at 1273 K for 30 min)enhances the ductility and strength of the as-printed specimen,with the increase of fracture stress from(613±19)MPa to(781±20)MPa and the increase of fracture strain from(7.6±0.1)%to(9.5±0.4)%.Both the as-printed and solutionized samples exhibit good tensile shape memory effects with recovery rates>90%.This work suggests that post-process heat treatment is essential to optimize the microstructure and improve the mechanical performances of the L-PBF in-situ alloyed parts.展开更多
Phase change energy storage is one of the solutions to effectively deal with the problemof intermittency and spatial and temporal mismatch between supply and demand of new energy sources(solar,wind,etc.).However,phase...Phase change energy storage is one of the solutions to effectively deal with the problemof intermittency and spatial and temporal mismatch between supply and demand of new energy sources(solar,wind,etc.).However,phase change materials(PCMs)suffer fromlowthermal conductivity,which greatly affects energy storage and release efficiency.In this study,a novel shape-stable phase change material(SSPCM)was prepared by mixing coconut oil(CO)as a PCM with aluminum nitride(AlN)thermally conductive reinforcing particles and vacuum impregnated into expanded graphite(EG).The results showed that the thermal conductivity of the prepared SSPCM reached 2.985W·m^(-1)·K^(-1),which was 1765%higher than that of pure CO.The latent heat of SSPCM was 83.67 J·g^(-1),which was 99%of the theoretical value.Furthermore,SSPCM showed excellent thermal stability and thermal cycle reliability.The proposed SSPCMs have the advantages of being renewable and simple preparation methods,which have great potential for application.展开更多
Spinal cord injury is an intractable traumatic injury. The most common hurdles faced during spinal cord injury are failure of axonal regrowth and reconnection to target sites. These also tend to be the most challengin...Spinal cord injury is an intractable traumatic injury. The most common hurdles faced during spinal cord injury are failure of axonal regrowth and reconnection to target sites. These also tend to be the most challenging issues in spinal cord injury. As spinal cord injury progresses to the chronic phase, lost motor and sensory functions are not recovered. Several reasons may be attributed to the failure of recovery from chronic spinal cord injury. These include factors that inhibit axonal growth such as activated astrocytes, chondroitin sulfate proteoglycan, myelin-associated proteins, inflammatory microglia, and fibroblasts that accumulate at lesion sites. Skeletal muscle atrophy due to denervation is another chronic and detrimental spinal cord injury–specific condition. Although several intervention strategies based on multiple outlooks have been attempted for treating spinal cord injury, few approaches have been successful. To treat chronic spinal cord injury, neural cells or tissue substitutes may need to be supplied in the cavity area to enable possible axonal growth. Additionally, stimulating axonal growth activity by extrinsic factors is extremely important and essential for maintaining the remaining host neurons and transplanted neurons. This review focuses on pharmacotherapeutic approaches using small compounds and proteins to enable axonal growth in chronic spinal cord injury. This review presents some of these candidates that have shown promising outcomes in basic research(in vivo animal studies) and clinical trials: AA-NgR(310)ecto-Fc(AXER-204), fasudil, phosphatase and tensin homolog protein antagonist peptide 4, chondroitinase ABC, intracellular sigma peptide,(-)-epigallocatechin gallate, matrine, acteoside, pyrvate kinase M2, diosgenin, granulocyte-colony stimulating factor, and fampridine-sustained release. Although the current situation suggests that drug-based therapies to recover function in chronic spinal cord injury are limited, potential candidates have been identified through basic research, and these candidates may be subjects of clinical studies in the future. Moreover, cocktail therapy comprising drugs with varied underlying mechanisms may be effective in treating the refractory status of chronic spinal cord injury.展开更多
As an advanced device for observing atmospheric winds,the spaceborne Doppler Asymmetric Spatial Heterodyne(DASH)interferometer also encounters challenges associated with phase distortion,par-ticularly in limb sounding...As an advanced device for observing atmospheric winds,the spaceborne Doppler Asymmetric Spatial Heterodyne(DASH)interferometer also encounters challenges associated with phase distortion,par-ticularly in limb sounding scenarios.This paper discusses interferogram modeling and phase distortion cor-rection techniques for spaceborne DASH interferometers.The modeling of phase distortion interferograms with and without Doppler shift for limb observation was conducted,and the effectiveness of the analytical expression was verified through numerical simulation.The simulation results indicate that errors propagate layer by layer while using the onion-peeling inversion algorithm to handle phase-distorted interferograms.In contrast,the phase distortion correction algorithm can achieve effective correction.This phase correction method can be successfully applied to correct phase distortions in the interferograms of the spaceborne DASH interferometer,providing a feasible solution to enhance its measurement accuracy.展开更多
We adopted the solution impregnation route with aluminum dihydrogen phosphate solution as liquid medium for effective surface modification on graphite substrate.The mass ratio of graphite to Al(H_(2)PO_(4))_(3) change...We adopted the solution impregnation route with aluminum dihydrogen phosphate solution as liquid medium for effective surface modification on graphite substrate.The mass ratio of graphite to Al(H_(2)PO_(4))_(3) changed from 0.5:1 to 4:1,and the impregnation time changed from 1 to 7 h.The typical composite phase change thermal storage materials doped with the as-treated graphite were fabricated using form-stable technique.To investigate the oxidation and anti-oxidation behavior of the impregnated graphite at high temperatures,the samples were put into a muffle furnace for a cyclic heat test.Based on SEM,EDS,DSC techniques,analyses on the impregnated technique suggested an optimized processing conditions of a 3 h impregnation time with the ratio of graphite:Al(H_(2)PO_(4))_(3) as 1:3 for graphite impregnation treatment.Further investigations on high-temperature phase change heat storage materials doped by the treated graphite suggested excellent oxidation resistance and thermal cycling performance.展开更多
Gradient magnetic heterointerfaces have injected infinite vitality in optimizing impedance matching,adjusting dielectric/magnetic resonance and promoting electromagnetic(EM)wave absorption,but still exist a significan...Gradient magnetic heterointerfaces have injected infinite vitality in optimizing impedance matching,adjusting dielectric/magnetic resonance and promoting electromagnetic(EM)wave absorption,but still exist a significant challenging in regulating local phase evolution.Herein,accordion-shaped Co/Co_(3)O_(4)@N-doped carbon nanosheets(Co/Co_(3)O_(4)@NC)with gradient magnetic heterointerfaces have been fabricated via the cooperative high-temperature carbonization and lowtemperature oxidation process.The results indicate that the surface epitaxial growth of crystal Co_(3)O_(4) domains on local Co nanoparticles realizes the adjustment of magnetic-heteroatomic components,which are beneficial for optimizing impedance matching and interfacial polarization.Moreover,gradient magnetic heterointerfaces simultaneously realize magnetic coupling,and long-range magnetic diffraction.Specifically,the synthesized Co/Co_(3)O_(4)@NC absorbents display the strong electromagnetic wave attenuation capability of−53.5 dB at a thickness of 3.0 mm with an effective absorption bandwidth of 5.36 GHz,both are superior to those of single magnetic domains embedded in carbon matrix.This design concept provides us an inspiration in optimizing interfacial polarization,regulating magnetic coupling and promoting electromagnetic wave absorption.展开更多
Background: Obesity, particularly abdominal obesity, is a well-established risk factor for arterial stiffness (AS) and cardiovascular diseases. A Body Shape Index (ABSI) is a novel anthropometric measure designed to a...Background: Obesity, particularly abdominal obesity, is a well-established risk factor for arterial stiffness (AS) and cardiovascular diseases. A Body Shape Index (ABSI) is a novel anthropometric measure designed to assess abdominal obesity, yet its association with AS remains inconclusive. This study aims to investigate the relationship between ABSI and AS indicators in a general population. Methods: This cross-sectional study included 721 participants from the general population of Dali, Yunnan Province, China. ABSI was calculated using a standardized formula. Univariate and multivariate linear regression analyses were performed to examine the associations between ABSI and AS indicators, including brachial-ankle pulse wave velocity (ba-PWV) and carotid-femoral pulse wave velocity (cf-PWV). Results: Higher ABSI tertiles were significantly associated with increased ba-PWV and cf-PWV compared to the lowest tertile (P ≤ 0.007). However, after adjusting for potential confounders, these associations became non-significant (P ≥ 0.058), suggesting that ABSI is not an independent predictor of AS. Conclusions: The initial association between ABSI and AS was attenuated after covariate adjustment, suggesting ABSI is not an independent AS marker. Further research is warranted to understand the complex interactions between ABSI and other cardiovascular risk factors and its potential role in AS risk assessment.展开更多
In the energy industry landscape,thermal power generation stands as a critical energy supply method,and the safety of its construction and operation is paramount.Currently,all stages of the life cycle of construction ...In the energy industry landscape,thermal power generation stands as a critical energy supply method,and the safety of its construction and operation is paramount.Currently,all stages of the life cycle of construction projects have garnered widespread attention.Among these,the infrastructure construction and operation phases of thermal power generation enterprises pose numerous issues worthy of in-depth study in terms of safety production management.This article starts by examining safety production management during these two phases,analyzing characteristics such as management models,legal bases,and responsible entities.It explores the reasons behind these characteristics and elaborates on key management priorities,providing a comprehensive and insightful reference for safety production management in thermal power generation enterprises.展开更多
Comprehensive understanding of the direct transformation pathway from graphite to diamond under high temperature and high pressure has long been one of the fundamental goals in materials science.Despite considerable e...Comprehensive understanding of the direct transformation pathway from graphite to diamond under high temperature and high pressure has long been one of the fundamental goals in materials science.Despite considerable experimental and theoretical progress,current experimental studies have mainly focused on the local microstructural characterizations of recovered samples,which has certain limitations for hightemperature and high-pressure products,which often exhibit diversity.Here,we report on the pressure-induced phase transition behavior of natural single-crystal graphite under three distinct pressure-transmitting media from a macroscopic perspective using in situ two-dimensional Raman spectroscopy,scanning electron microscopy,and atomic force microscopy.The surface evolution process of graphite before and after the phase transition is captured,revealing that pressure-induced surface textures can impede the continuity of the phase transition process across the entire single crystal.Our results provide a fresh perspective for studying the phase transition behavior of graphite and greatly deepen our understanding of this behavior,which will be helpful in guiding further high-temperature and high-pressure syntheses of carbon allotropes.展开更多
Polymethyl methacrylate(PMMA)is an optically transparent thermoplastic with favorable processing conditions.In this study,a series of plastic scintillators are prepared via thermal polymerization,and the impact of PMM...Polymethyl methacrylate(PMMA)is an optically transparent thermoplastic with favorable processing conditions.In this study,a series of plastic scintillators are prepared via thermal polymerization,and the impact of PMMA content on their transparency and pulse shape discrimination(PSD)ability is investigated.The fabricated samples,comprising a polystyrene(PS)-PMMA matrix,30.0 wt%2,5-diphenyloxazole(PPO),and 0.2 wt%9,10-diphenylanthracene(DPA),exhibit high transparency with transmissivity ranging from 70.0 to 90.0%(above 415.0 nm)and demonstrate excellent n/γdiscrimination capability.Transparency increased with increasing PMMA content across the entire visible light spectrum.However,the PSD performance gradually deteriorated when the aromatic matrix was replaced with PMMA.The scintillator containing 20.0 wt%PMMA demonstrated the best stability concerning PSD properties and relative light yields.展开更多
The equilibrium phase relations of the CaO–SiO_(2)–TiO_(2)–5wt%Fe_(3)O_(4)system were experimentally investigated at 1400℃ in air High-temperature equilibration-quenching techniques were employed in an electric Mo...The equilibrium phase relations of the CaO–SiO_(2)–TiO_(2)–5wt%Fe_(3)O_(4)system were experimentally investigated at 1400℃ in air High-temperature equilibration-quenching techniques were employed in an electric MoSi2resistance heated furnace,with phase composition analysis conducted using an electron probe microanalyzer and X-ray diffraction.A single liquid region,liquid–solid phase equilibria regions (including liquid–tridymite,liquid–rutile,liquid–perovskite,and liquid–wollastonite),and three-phase equilibria regions of liquid–tridymite–rutile and liquid–rutile–perovskite were found.The 1400℃ isothermal sections of the CaO-SiO_(2)-TiO_(2)-5wt%Fe_(3)O_(4)system in air were projected.The present experimental results exhibited good agreement with the calculation results obtained from FactSage.展开更多
The optimization of civil engineering structures is critical for enhancing structural performance and material efficiency in engineering applications.Structural optimization approaches seek to determine the optimal de...The optimization of civil engineering structures is critical for enhancing structural performance and material efficiency in engineering applications.Structural optimization approaches seek to determine the optimal design,by considering material performance,cost,and structural safety.The design approaches aim to reduce the built environment’s energy use and carbon emissions.This comprehensive review examines optimization techniques,including size,shape,topology,and multi-objective approaches,by integrating these methodologies.The trends and advancements that contribute to developing more efficient,cost-effective,and reliable structural designs were identified.The review also discusses emerging technologies,such as machine learning applications with different optimization techniques.Optimization of truss,frame,tensegrity,reinforced concrete,origami,pantographic,and adaptive structures are covered and discussed.Optimization techniques are explained,including metaheuristics,genetic algorithm,particle swarm,ant-colony,harmony search algorithm,and their applications with mentioned structure types.Linear and non-linear structures,including geometric and material nonlinearity,are distinguished.The role of optimization in active structures,structural design,seismic design,form-finding,and structural control is taken into account,and the most recent techniques and advancements are mentioned.展开更多
Background Three-dimensional(3D)shape representation using mesh data is essential in various applications,such as virtual reality and simulation technologies.Current methods for extracting features from mesh edges or ...Background Three-dimensional(3D)shape representation using mesh data is essential in various applications,such as virtual reality and simulation technologies.Current methods for extracting features from mesh edges or faces struggle with complex 3D models because edge-based approaches miss global contexts and face-based methods overlook variations in adjacent areas,which affects the overall precision.To address these issues,we propose the Feature Discrimination and Context Propagation Network(FDCPNet),which is a novel approach that synergistically integrates local and global features in mesh datasets.Methods FDCPNet is composed of two modules:(1)the Feature Discrimination Module,which employs an attention mechanism to enhance the identification of key local features,and(2)the Context Propagation Module,which enriches key local features by integrating global contextual information,thereby facilitating a more detailed and comprehensive representation of crucial areas within the mesh model.Results Experiments on popular datasets validated the effectiveness of FDCPNet,showing an improvement in the classification accuracy over the baseline MeshNet.Furthermore,even with reduced mesh face numbers and limited training data,FDCPNet achieved promising results,demonstrating its robustness in scenarios of variable complexity.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
Degradation of materials is one of the most critical aging mechanisms affecting the performance of lithium batteries.Among the various approaches to investigate battery aging,phase-field modelling(PFM)has emerged as a...Degradation of materials is one of the most critical aging mechanisms affecting the performance of lithium batteries.Among the various approaches to investigate battery aging,phase-field modelling(PFM)has emerged as a widely used numerical method for simulating the evolution of the phase interface as a function of space and time during material phase transition process.Moreover,PFM coupled with multi-physics analyses is particularly well-suited for investigating the mesoscale microstructural evolution of materials,providing quantitative understandings of aging and failure mechanisms in lithium batteries.In this paper,we comprehensively overview the state-of-art applications of PFM in the research of degradation and failure processes in lithium batteries,particularly focusing on the theoretical framework and development of the PFMs for lithium deposition/dissolution,phase separation,and crack propagation.Furthermore,we summarize the existing challenges and prospect some future developments in PFMs,aiming to offer new insights into the advancement of PFM and ultimately enhance the development of lithium batteries.展开更多
Diatomic metasurfaces designed for interferometric mechanisms possess significant potential for the multidimensional manipulation of electromagnetic waves,including control over amplitude,phase,frequency,and polarizat...Diatomic metasurfaces designed for interferometric mechanisms possess significant potential for the multidimensional manipulation of electromagnetic waves,including control over amplitude,phase,frequency,and polarization.Geometric phase profiles with spin-selective properties are commonly associated with wavefront modulation,allowing the implementation of conjugate strategies within orthogonal circularly polarized channels.Simultaneous control of these characteristics in a single-layered diatomic metasurface will be an apparent technological extension.Here,spin-selective modulation of terahertz(THz)beams is realized by assembling a pair of meta-atoms with birefringent effects.The distinct modulation functions arise from geometric phase profiles characterized by multiple rotational properties,which introduce independent parametric factors that elucidate their physical significance.By arranging the key parameters,the proposed design strategy can be employed to realize independent amplitude and phase manipulation.A series of THz metasurface samples with specific modulation functions are characterized,experimentally demonstrating the accuracy of on-demand manipulation.This research paves the way for all-silicon meta-optics that may have great potential in imaging,sensing and detection.展开更多
Lead chalcogenides represent a significant class of materials that exhibit intriguing physical phenomena,including remarkable thermoelectric properties and superconductivity.In this study,we present a comprehensive in...Lead chalcogenides represent a significant class of materials that exhibit intriguing physical phenomena,including remarkable thermoelectric properties and superconductivity.In this study,we present a comprehensive investigation on the superconductivity of PbSe single crystal under high pressure.The signature of superconducting(SC)transition starts to appear at 7.2 K under 16.5 GPa.Upon further compression,the SC temperature(T_(c))decreases,and it is reduced to 3.5 K at 45.0 GPa.The negative pressure dependent behavior of T_(c)is consistent with the trend of T_(c)-P relations observed in other lead chalcogenides.The highest T_(c)is 8.0 K observed at 20.5 GPa during decompression process,which is also the highest record among all other PbSe derivatives,such as doped samples,superlattices,and so on.The phase boundaries of the structural and electronic transitions are well defined by Raman spectroscopy,and then phase diagrams are plotted for both compression and decompression processes.This work corrects the previous claim of positive pressure dependence of T_(c)in PbSe and provides clear phase diagrams for intrinsic superconductivity in PbSe under pressure.展开更多
To investigate the performance of utilizing the shape memory effect of SMA(Shape Memory Alloy)wire to generate recovery stress,this paper performed single heating recovery stress tests and reciprocating heating-coolin...To investigate the performance of utilizing the shape memory effect of SMA(Shape Memory Alloy)wire to generate recovery stress,this paper performed single heating recovery stress tests and reciprocating heating-cooling recovery stress tests on SMA wire under varying initial strain conditions.The effects of various strains and different energized heating methods on the recovery stress of SMA wires were explored in the single heating tests.The SMA wire was strained from 2%to 8%initially,and two distinct heating approaches were employed:one using a large current interval for rapid heating and one using a small current interval for slower heating.The experimental outcomes reveal that during a single heating cycle,the temperature-recovery stress relationship of SMA wire exhibits three distinct stages:the martensite phase stage,the transition stage from martensite to austenite phase,and the austenite phase stage.Notably,the choice of heating method does not influence the maximum recovery stress value,and the correlation between initial strain and maximum recovery stress is predominantly linear.Moreover,conducting the reciprocating temperature rise and fall performance test is important to better simulate the scenario in practical engineering where multiple recovery stress in SMA wires for structural repair.In this test,two temperature cycling methods were studied:interval rise and fall,as well as direct rise and fall.In the case of utilizing the interval temperature rise and fall method,it was observed that the recovery stress associated with cooling was significantly higher than that corresponding to heating at the same temperature.Furthermore,the recovery stress was lower upon subsequent heating than that measured during the previous heating cycle.Based on the experimental results,a prediction model for the temperature-recovery stress relationship has been proposed to simplify numerical calculations.It is hoped that an approximate temperaturerecovery stress curve can be obtained from the parameters of the SMA wire.The calculated values derived from this model show good alignment with the measured values,indicating its reliability.展开更多
基金financially supported by the National Natural Science Foundation of China(No.51974028)。
文摘The martensitic transformation temperature is the basis for the application of shape memory alloys(SMAs),and the ability to quickly and accurately predict the transformation temperature of SMAs has very important practical significance.In this work,machine learning(ML)methods were utilized to accelerate the search for shape memory alloys with targeted properties(phase transition temperature).A group of component data was selected to design shape memory alloys using reverse design method from numerous unexplored data.Component modeling and feature modeling were used to predict the phase transition temperature of the shape memory alloys.The experimental results of the shape memory alloys were obtained to verify the effectiveness of the support vector regression(SVR)model.The results show that the machine learning model can obtain target materials more efficiently and pertinently,and realize the accurate and rapid design of shape memory alloys with specific target phase transition temperature.On this basis,the relationship between phase transition temperature and material descriptors is analyzed,and it is proved that the key factors affecting the phase transition temperature of shape memory alloys are based on the strength of the bond energy between atoms.This work provides new ideas for the controllable design and performance optimization of Cu-based shape memory alloys.
基金supported by the Natural Science Foundation of Shandong Province (ZR2020YQ39, ZR2020ZD05)Taishan Scholar Foundation of Shandong Province (tsqn202211002)the Young Scholars Program of Shandong University (Grant Number 2018WLJH24)
文摘Post-heat treatment is commonly employed to improve the microstructural homogeneity and enhance the mechanical performances of the additively manufactured metallic materials.In this work,a ternary(NiTi)91Nb9(at.%)shape memory alloy was produced by laser powder bed fusion(L-PBF)using pre-alloyed NiTi and elemental Nb powders.The effect of solution treatment on the microstructure,phase transformation behavior and mechanical/functional performances was investigated.The in-situ alloyed(NiTi)91Nb9 alloy exhibits a submicron cellular-dendritic structure surrounding the supersaturated B2-NiTi matrix.Upon high-temperature(1273 K)solution treatment,Nb-rich precipitates were precipitated from the supersaturated matrix.The fragmentation and spheroidization of the NiTi/Nb eutectics occurred during solution treatment,leading to a morphological transition from mesh-like into rod-like and sphere-like.Coarsening of theβ-Nb phases occurred with increasing holding time.The martensite transformation temperature increases after solution treatment,mainly attributed to:(i)reduced lattice distortion due to the Nb expulsion from the supersaturated B2-NiTi,and(ii)the Ti expulsion from theβ-Nb phases that lowers the ratio Ni/Ti in the B2-NiTi matrix,which resulted from the microstructure changes from non-equilibrium to equilibrium state.The thermal hysteresis of the solutionized alloys is around 145 K after 20%pre-deformation,which is comparable to the conventional NiTiNb alloys.A short-term solution treatment(i.e.at 1273 K for 30 min)enhances the ductility and strength of the as-printed specimen,with the increase of fracture stress from(613±19)MPa to(781±20)MPa and the increase of fracture strain from(7.6±0.1)%to(9.5±0.4)%.Both the as-printed and solutionized samples exhibit good tensile shape memory effects with recovery rates>90%.This work suggests that post-process heat treatment is essential to optimize the microstructure and improve the mechanical performances of the L-PBF in-situ alloyed parts.
文摘Phase change energy storage is one of the solutions to effectively deal with the problemof intermittency and spatial and temporal mismatch between supply and demand of new energy sources(solar,wind,etc.).However,phase change materials(PCMs)suffer fromlowthermal conductivity,which greatly affects energy storage and release efficiency.In this study,a novel shape-stable phase change material(SSPCM)was prepared by mixing coconut oil(CO)as a PCM with aluminum nitride(AlN)thermally conductive reinforcing particles and vacuum impregnated into expanded graphite(EG).The results showed that the thermal conductivity of the prepared SSPCM reached 2.985W·m^(-1)·K^(-1),which was 1765%higher than that of pure CO.The latent heat of SSPCM was 83.67 J·g^(-1),which was 99%of the theoretical value.Furthermore,SSPCM showed excellent thermal stability and thermal cycle reliability.The proposed SSPCMs have the advantages of being renewable and simple preparation methods,which have great potential for application.
文摘Spinal cord injury is an intractable traumatic injury. The most common hurdles faced during spinal cord injury are failure of axonal regrowth and reconnection to target sites. These also tend to be the most challenging issues in spinal cord injury. As spinal cord injury progresses to the chronic phase, lost motor and sensory functions are not recovered. Several reasons may be attributed to the failure of recovery from chronic spinal cord injury. These include factors that inhibit axonal growth such as activated astrocytes, chondroitin sulfate proteoglycan, myelin-associated proteins, inflammatory microglia, and fibroblasts that accumulate at lesion sites. Skeletal muscle atrophy due to denervation is another chronic and detrimental spinal cord injury–specific condition. Although several intervention strategies based on multiple outlooks have been attempted for treating spinal cord injury, few approaches have been successful. To treat chronic spinal cord injury, neural cells or tissue substitutes may need to be supplied in the cavity area to enable possible axonal growth. Additionally, stimulating axonal growth activity by extrinsic factors is extremely important and essential for maintaining the remaining host neurons and transplanted neurons. This review focuses on pharmacotherapeutic approaches using small compounds and proteins to enable axonal growth in chronic spinal cord injury. This review presents some of these candidates that have shown promising outcomes in basic research(in vivo animal studies) and clinical trials: AA-NgR(310)ecto-Fc(AXER-204), fasudil, phosphatase and tensin homolog protein antagonist peptide 4, chondroitinase ABC, intracellular sigma peptide,(-)-epigallocatechin gallate, matrine, acteoside, pyrvate kinase M2, diosgenin, granulocyte-colony stimulating factor, and fampridine-sustained release. Although the current situation suggests that drug-based therapies to recover function in chronic spinal cord injury are limited, potential candidates have been identified through basic research, and these candidates may be subjects of clinical studies in the future. Moreover, cocktail therapy comprising drugs with varied underlying mechanisms may be effective in treating the refractory status of chronic spinal cord injury.
文摘As an advanced device for observing atmospheric winds,the spaceborne Doppler Asymmetric Spatial Heterodyne(DASH)interferometer also encounters challenges associated with phase distortion,par-ticularly in limb sounding scenarios.This paper discusses interferogram modeling and phase distortion cor-rection techniques for spaceborne DASH interferometers.The modeling of phase distortion interferograms with and without Doppler shift for limb observation was conducted,and the effectiveness of the analytical expression was verified through numerical simulation.The simulation results indicate that errors propagate layer by layer while using the onion-peeling inversion algorithm to handle phase-distorted interferograms.In contrast,the phase distortion correction algorithm can achieve effective correction.This phase correction method can be successfully applied to correct phase distortions in the interferograms of the spaceborne DASH interferometer,providing a feasible solution to enhance its measurement accuracy.
基金Funded by Scientific and Technological Innovation Project of Carbon Emission Peak and Carbon Neutrality of Jiangsu Province(No.BE2022028-4)。
文摘We adopted the solution impregnation route with aluminum dihydrogen phosphate solution as liquid medium for effective surface modification on graphite substrate.The mass ratio of graphite to Al(H_(2)PO_(4))_(3) changed from 0.5:1 to 4:1,and the impregnation time changed from 1 to 7 h.The typical composite phase change thermal storage materials doped with the as-treated graphite were fabricated using form-stable technique.To investigate the oxidation and anti-oxidation behavior of the impregnated graphite at high temperatures,the samples were put into a muffle furnace for a cyclic heat test.Based on SEM,EDS,DSC techniques,analyses on the impregnated technique suggested an optimized processing conditions of a 3 h impregnation time with the ratio of graphite:Al(H_(2)PO_(4))_(3) as 1:3 for graphite impregnation treatment.Further investigations on high-temperature phase change heat storage materials doped by the treated graphite suggested excellent oxidation resistance and thermal cycling performance.
基金financially supported by the National Natural Science Foundation of China(52373271)Science,Technology and Innovation Commission of Shenzhen Municipality under Grant(KCXFZ20201221173004012)+1 种基金National Key Research and Development Program of Shaanxi Province(No.2023-YBNY-271)Open Testing Foundation of the Analytical&Testing Center of Northwestern Polytechnical University(2023T019).
文摘Gradient magnetic heterointerfaces have injected infinite vitality in optimizing impedance matching,adjusting dielectric/magnetic resonance and promoting electromagnetic(EM)wave absorption,but still exist a significant challenging in regulating local phase evolution.Herein,accordion-shaped Co/Co_(3)O_(4)@N-doped carbon nanosheets(Co/Co_(3)O_(4)@NC)with gradient magnetic heterointerfaces have been fabricated via the cooperative high-temperature carbonization and lowtemperature oxidation process.The results indicate that the surface epitaxial growth of crystal Co_(3)O_(4) domains on local Co nanoparticles realizes the adjustment of magnetic-heteroatomic components,which are beneficial for optimizing impedance matching and interfacial polarization.Moreover,gradient magnetic heterointerfaces simultaneously realize magnetic coupling,and long-range magnetic diffraction.Specifically,the synthesized Co/Co_(3)O_(4)@NC absorbents display the strong electromagnetic wave attenuation capability of−53.5 dB at a thickness of 3.0 mm with an effective absorption bandwidth of 5.36 GHz,both are superior to those of single magnetic domains embedded in carbon matrix.This design concept provides us an inspiration in optimizing interfacial polarization,regulating magnetic coupling and promoting electromagnetic wave absorption.
文摘Background: Obesity, particularly abdominal obesity, is a well-established risk factor for arterial stiffness (AS) and cardiovascular diseases. A Body Shape Index (ABSI) is a novel anthropometric measure designed to assess abdominal obesity, yet its association with AS remains inconclusive. This study aims to investigate the relationship between ABSI and AS indicators in a general population. Methods: This cross-sectional study included 721 participants from the general population of Dali, Yunnan Province, China. ABSI was calculated using a standardized formula. Univariate and multivariate linear regression analyses were performed to examine the associations between ABSI and AS indicators, including brachial-ankle pulse wave velocity (ba-PWV) and carotid-femoral pulse wave velocity (cf-PWV). Results: Higher ABSI tertiles were significantly associated with increased ba-PWV and cf-PWV compared to the lowest tertile (P ≤ 0.007). However, after adjusting for potential confounders, these associations became non-significant (P ≥ 0.058), suggesting that ABSI is not an independent predictor of AS. Conclusions: The initial association between ABSI and AS was attenuated after covariate adjustment, suggesting ABSI is not an independent AS marker. Further research is warranted to understand the complex interactions between ABSI and other cardiovascular risk factors and its potential role in AS risk assessment.
文摘In the energy industry landscape,thermal power generation stands as a critical energy supply method,and the safety of its construction and operation is paramount.Currently,all stages of the life cycle of construction projects have garnered widespread attention.Among these,the infrastructure construction and operation phases of thermal power generation enterprises pose numerous issues worthy of in-depth study in terms of safety production management.This article starts by examining safety production management during these two phases,analyzing characteristics such as management models,legal bases,and responsible entities.It explores the reasons behind these characteristics and elaborates on key management priorities,providing a comprehensive and insightful reference for safety production management in thermal power generation enterprises.
基金support from the National Science Fund for Distinguished Young Scholars(Grant No.T2225027)the NSAF(Grant No.U1930401)+1 种基金the National Key R&D Program of China(MOST)(Grant No.2023YFA1406500)the National Natural Science Foundation of China(NSFC)(Grant No.61674045).
文摘Comprehensive understanding of the direct transformation pathway from graphite to diamond under high temperature and high pressure has long been one of the fundamental goals in materials science.Despite considerable experimental and theoretical progress,current experimental studies have mainly focused on the local microstructural characterizations of recovered samples,which has certain limitations for hightemperature and high-pressure products,which often exhibit diversity.Here,we report on the pressure-induced phase transition behavior of natural single-crystal graphite under three distinct pressure-transmitting media from a macroscopic perspective using in situ two-dimensional Raman spectroscopy,scanning electron microscopy,and atomic force microscopy.The surface evolution process of graphite before and after the phase transition is captured,revealing that pressure-induced surface textures can impede the continuity of the phase transition process across the entire single crystal.Our results provide a fresh perspective for studying the phase transition behavior of graphite and greatly deepen our understanding of this behavior,which will be helpful in guiding further high-temperature and high-pressure syntheses of carbon allotropes.
基金supported by the National Natural Science Foundation of China(No.12027813)the fund of National Innovation Center of Radiation Application of China(Nos.KFZC2020020501,KFZC2021010101).
文摘Polymethyl methacrylate(PMMA)is an optically transparent thermoplastic with favorable processing conditions.In this study,a series of plastic scintillators are prepared via thermal polymerization,and the impact of PMMA content on their transparency and pulse shape discrimination(PSD)ability is investigated.The fabricated samples,comprising a polystyrene(PS)-PMMA matrix,30.0 wt%2,5-diphenyloxazole(PPO),and 0.2 wt%9,10-diphenylanthracene(DPA),exhibit high transparency with transmissivity ranging from 70.0 to 90.0%(above 415.0 nm)and demonstrate excellent n/γdiscrimination capability.Transparency increased with increasing PMMA content across the entire visible light spectrum.However,the PSD performance gradually deteriorated when the aromatic matrix was replaced with PMMA.The scintillator containing 20.0 wt%PMMA demonstrated the best stability concerning PSD properties and relative light yields.
基金financially supported from the National Natural Science Foundation of China (No. 52204310)the National Key Research and Development Program of China (No. 2021YFC2901000)+4 种基金the China Postdoctoral Science Foundation (Nos. 2020TQ0059 and 2020M570967)the Natural Science Foundation of Liaoning Province, China (No. 2021-MS-083)the Fundamental Research Funds for the Central Universities, China (No. N2125010)the Open Project Program of Key Laboratory of Metallurgical Emission Reduction & Resources Recycling (Anhui University of Technology), Ministry of Education, China (No. JKF22-02)the Key Laboratory for Anisotropy and Texture of Materials, Ministry of Education, China。
文摘The equilibrium phase relations of the CaO–SiO_(2)–TiO_(2)–5wt%Fe_(3)O_(4)system were experimentally investigated at 1400℃ in air High-temperature equilibration-quenching techniques were employed in an electric MoSi2resistance heated furnace,with phase composition analysis conducted using an electron probe microanalyzer and X-ray diffraction.A single liquid region,liquid–solid phase equilibria regions (including liquid–tridymite,liquid–rutile,liquid–perovskite,and liquid–wollastonite),and three-phase equilibria regions of liquid–tridymite–rutile and liquid–rutile–perovskite were found.The 1400℃ isothermal sections of the CaO-SiO_(2)-TiO_(2)-5wt%Fe_(3)O_(4)system in air were projected.The present experimental results exhibited good agreement with the calculation results obtained from FactSage.
文摘The optimization of civil engineering structures is critical for enhancing structural performance and material efficiency in engineering applications.Structural optimization approaches seek to determine the optimal design,by considering material performance,cost,and structural safety.The design approaches aim to reduce the built environment’s energy use and carbon emissions.This comprehensive review examines optimization techniques,including size,shape,topology,and multi-objective approaches,by integrating these methodologies.The trends and advancements that contribute to developing more efficient,cost-effective,and reliable structural designs were identified.The review also discusses emerging technologies,such as machine learning applications with different optimization techniques.Optimization of truss,frame,tensegrity,reinforced concrete,origami,pantographic,and adaptive structures are covered and discussed.Optimization techniques are explained,including metaheuristics,genetic algorithm,particle swarm,ant-colony,harmony search algorithm,and their applications with mentioned structure types.Linear and non-linear structures,including geometric and material nonlinearity,are distinguished.The role of optimization in active structures,structural design,seismic design,form-finding,and structural control is taken into account,and the most recent techniques and advancements are mentioned.
基金Supported by the National Key R&D Program of China(2022YFC3803600).
文摘Background Three-dimensional(3D)shape representation using mesh data is essential in various applications,such as virtual reality and simulation technologies.Current methods for extracting features from mesh edges or faces struggle with complex 3D models because edge-based approaches miss global contexts and face-based methods overlook variations in adjacent areas,which affects the overall precision.To address these issues,we propose the Feature Discrimination and Context Propagation Network(FDCPNet),which is a novel approach that synergistically integrates local and global features in mesh datasets.Methods FDCPNet is composed of two modules:(1)the Feature Discrimination Module,which employs an attention mechanism to enhance the identification of key local features,and(2)the Context Propagation Module,which enriches key local features by integrating global contextual information,thereby facilitating a more detailed and comprehensive representation of crucial areas within the mesh model.Results Experiments on popular datasets validated the effectiveness of FDCPNet,showing an improvement in the classification accuracy over the baseline MeshNet.Furthermore,even with reduced mesh face numbers and limited training data,FDCPNet achieved promising results,demonstrating its robustness in scenarios of variable complexity.
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)and 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financially supported by the National Key R&D Program of China(2021YFB2401800)。
文摘Degradation of materials is one of the most critical aging mechanisms affecting the performance of lithium batteries.Among the various approaches to investigate battery aging,phase-field modelling(PFM)has emerged as a widely used numerical method for simulating the evolution of the phase interface as a function of space and time during material phase transition process.Moreover,PFM coupled with multi-physics analyses is particularly well-suited for investigating the mesoscale microstructural evolution of materials,providing quantitative understandings of aging and failure mechanisms in lithium batteries.In this paper,we comprehensively overview the state-of-art applications of PFM in the research of degradation and failure processes in lithium batteries,particularly focusing on the theoretical framework and development of the PFMs for lithium deposition/dissolution,phase separation,and crack propagation.Furthermore,we summarize the existing challenges and prospect some future developments in PFMs,aiming to offer new insights into the advancement of PFM and ultimately enhance the development of lithium batteries.
基金supports from National Key Research and Development Program of China(2021YFB2800703)Sichuan Province Science and Technology Support Program(25QNJJ2419)+1 种基金National Natural Science Foundation of China(U22A2008,12404484)Laoshan Laboratory Science and Technology Innovation Project(LSKJ202200801).
文摘Diatomic metasurfaces designed for interferometric mechanisms possess significant potential for the multidimensional manipulation of electromagnetic waves,including control over amplitude,phase,frequency,and polarization.Geometric phase profiles with spin-selective properties are commonly associated with wavefront modulation,allowing the implementation of conjugate strategies within orthogonal circularly polarized channels.Simultaneous control of these characteristics in a single-layered diatomic metasurface will be an apparent technological extension.Here,spin-selective modulation of terahertz(THz)beams is realized by assembling a pair of meta-atoms with birefringent effects.The distinct modulation functions arise from geometric phase profiles characterized by multiple rotational properties,which introduce independent parametric factors that elucidate their physical significance.By arranging the key parameters,the proposed design strategy can be employed to realize independent amplitude and phase manipulation.A series of THz metasurface samples with specific modulation functions are characterized,experimentally demonstrating the accuracy of on-demand manipulation.This research paves the way for all-silicon meta-optics that may have great potential in imaging,sensing and detection.
基金supported by the National Natural Science Foundation of China(Grant Nos.12374050,12004014,U1930401,and 12375304)the National Key R&D Program of China(Grant Nos.2021YFA1400300 and 2023YFA1608900)the Major Program of the National Natural Science Foundation of China(Grant No.22090041).
文摘Lead chalcogenides represent a significant class of materials that exhibit intriguing physical phenomena,including remarkable thermoelectric properties and superconductivity.In this study,we present a comprehensive investigation on the superconductivity of PbSe single crystal under high pressure.The signature of superconducting(SC)transition starts to appear at 7.2 K under 16.5 GPa.Upon further compression,the SC temperature(T_(c))decreases,and it is reduced to 3.5 K at 45.0 GPa.The negative pressure dependent behavior of T_(c)is consistent with the trend of T_(c)-P relations observed in other lead chalcogenides.The highest T_(c)is 8.0 K observed at 20.5 GPa during decompression process,which is also the highest record among all other PbSe derivatives,such as doped samples,superlattices,and so on.The phase boundaries of the structural and electronic transitions are well defined by Raman spectroscopy,and then phase diagrams are plotted for both compression and decompression processes.This work corrects the previous claim of positive pressure dependence of T_(c)in PbSe and provides clear phase diagrams for intrinsic superconductivity in PbSe under pressure.
基金financially supported by National Natural Science Foundation of China(Project No.51878156).
文摘To investigate the performance of utilizing the shape memory effect of SMA(Shape Memory Alloy)wire to generate recovery stress,this paper performed single heating recovery stress tests and reciprocating heating-cooling recovery stress tests on SMA wire under varying initial strain conditions.The effects of various strains and different energized heating methods on the recovery stress of SMA wires were explored in the single heating tests.The SMA wire was strained from 2%to 8%initially,and two distinct heating approaches were employed:one using a large current interval for rapid heating and one using a small current interval for slower heating.The experimental outcomes reveal that during a single heating cycle,the temperature-recovery stress relationship of SMA wire exhibits three distinct stages:the martensite phase stage,the transition stage from martensite to austenite phase,and the austenite phase stage.Notably,the choice of heating method does not influence the maximum recovery stress value,and the correlation between initial strain and maximum recovery stress is predominantly linear.Moreover,conducting the reciprocating temperature rise and fall performance test is important to better simulate the scenario in practical engineering where multiple recovery stress in SMA wires for structural repair.In this test,two temperature cycling methods were studied:interval rise and fall,as well as direct rise and fall.In the case of utilizing the interval temperature rise and fall method,it was observed that the recovery stress associated with cooling was significantly higher than that corresponding to heating at the same temperature.Furthermore,the recovery stress was lower upon subsequent heating than that measured during the previous heating cycle.Based on the experimental results,a prediction model for the temperature-recovery stress relationship has been proposed to simplify numerical calculations.It is hoped that an approximate temperaturerecovery stress curve can be obtained from the parameters of the SMA wire.The calculated values derived from this model show good alignment with the measured values,indicating its reliability.
