Spinal cord injury is a severe neurological disorder;however,current treatment methods often fail to restore nerve function effectively.Spinal cord stimulation via electrical signals is a promising therapeutic modalit...Spinal cord injury is a severe neurological disorder;however,current treatment methods often fail to restore nerve function effectively.Spinal cord stimulation via electrical signals is a promising therapeutic modality for spinal cord injury.Based on similar principles,this review aims to explore the potential of optical and acoustic neuromodulation techniques,emphasizing their benefits in the context of spinal cord injury.Photoacoustic imaging,renowned for its noninvasive nature,high-resolution capabilities,and cost-effectiveness,is well recognized for its role in early diagnosis,dynamic monitoring,and surgical guidance in stem cell therapies for spinal cord injury.Moreover,photoacoustodynamic therapy offers multiple pathways for tissue regeneration.Optogenetics and sonogenetics use genetic engineering to achieve precise neuronal activation,while photoacoustoelectric therapy leverages photovoltaic materials for electrical modulation of the nervous system,introducing an innovative paradigm for nerve system disorder management.Collectively,these advancements represent a transformative shift in the diagnosis and treatment of spinal cord injury,with the potential to significantly enhance nerve function remodeling and improve patient outcomes.展开更多
Silicide coatings have proven to be promising for improving the high-temperature oxidation resistance of niobium alloy.However,the long-term protective property of single silicide coating remains a long-time endeavor ...Silicide coatings have proven to be promising for improving the high-temperature oxidation resistance of niobium alloy.However,the long-term protective property of single silicide coating remains a long-time endeavor due to the deficiency of oxygen-consuming phases,as well as the self-healing ability of the protective layer.Herein,a silicide-based composite coating is constructed on niobium alloy by incor-poration of nano-SiC particles for enhancing the high-temperature oxidation resistance.Isothermal oxi-dation results at 1250℃ for 50 h indicate that NbSi_(2)/Nb_(2)O_(5)-SiO_(2)/SiC multilayer coated sample with a low mass gain of 2.49 mg/cm^(2) shows an improved oxidation resistance compared with NbSi_(2) coating(6.49 mg/cm^(2)).The enhanced high-temperature antioxidant performance of NbSi_(2)/Nb_(2)O_(5)-SiO_(2)/SiC multi-layer coating is mainly attributed to the formation of the protective SiO_(2) self-healing film and the high-temperature diffusion behavior of NbSi_(2)/substrate.展开更多
Geo-interfaces refer to the contact surfaces between multiple media within geological strata,as well as the transition zones that regulate the migration of three-phase matter,changes in physical states,and the deforma...Geo-interfaces refer to the contact surfaces between multiple media within geological strata,as well as the transition zones that regulate the migration of three-phase matter,changes in physical states,and the deformation and stability of rock and soil masses.Owing to the combined effects of natural factors and human activities,geo-interfaces play crucial roles in the emergence,propagation,and triggering of geological disasters.Over the past three decades,the material point method(MPM)has emerged as a preferred approach for addressing large deformation problems and simulating soil-water-structure interactions,making it an ideal tool for analyzing geo-interface behaviors.In this review,we offer a systematic summary of the basic concepts,classifications,and main characteristics of the geo-interface,and provide a comprehensive overview of recent advances and developments in simulating geo-interface using the MPM.We further present a brief description of various MPMs for modeling different types of geo-interfaces in geotechnical engineering applications and highlight the existing limitations and future research directions.This study aims to facilitate innovative applications of the MPM in modeling complex geo-interface problems,providing a reference for geotechnical practitioners and researchers.展开更多
Correctly tracking the evolution of spatial heterogeneity of local degree of saturation(Sr)in unsaturated soils is essential to explain the seepage phenomenon,which is crucial to assessing slope stability.Several meth...Correctly tracking the evolution of spatial heterogeneity of local degree of saturation(Sr)in unsaturated soils is essential to explain the seepage phenomenon,which is crucial to assessing slope stability.Several methods exist for quantifying the heterogeneity of local S_(r).However,a comprehensive comparison of these methods in terms of accuracy,relative advantages,and disadvantages is currently lacking.This paper presents a comparative analysis of local Sr obtained at multiple scales,ranging from the element scale to the slice,representative element volume(REV),pore,and voxel scales.The spatial heterogeneity of Sr in an unsaturated glass beads specimen at different matric suctions was visualised and quantified by multiscale X-ray micro-focus computed tomography image-based analysis methods.Local Sr obtained at different scales displayed a comparable trend along the sample depth,yet the REV-scale method showed a much scattered and discontinuous distribution.In contrast,the pore-scale method detected a distinct two-clustered,bimodal distribution of S_(r).The pore-scale method has the highest integrated resolution,as it has the highest spatial resolution(i.e.number of data points)and provides more information(i.e.number of extractable physical parameters).This method thus provides a more effective approach for tracking the spatial heterogeneity of S_(r).Based on this method,pore-scale water retention curves were determined,offering new quantitative means to characterise pore water heterogeneity and explainwater drainage processes such as hysteresis at the pore scale.展开更多
The mass discarding face masks has caused severe environmental problems during and after the COVID-19 pandemic.To reduce waste and minimize environmental impact,we present a new face mask featuring selfcharging extend...The mass discarding face masks has caused severe environmental problems during and after the COVID-19 pandemic.To reduce waste and minimize environmental impact,we present a new face mask featuring selfcharging extended service time and fully biodegradable materials.To extend the effective service time,we need to supplement the lost electric charge of the electret layer of face masks,for which task we propose to use the piezoelectric effect and generate electricity from breathing motions.However,existing piezoelectric materials are either toxic,impermeable,rigid,costly,or non-degradable.We synthesize a fully biodegradable piezoelectric membrane composed of polyvinyl alcohol(PVA)and glycine(GLY)via the electrospinning process.Parameters are accurately controlled to ensure that glycine crystallizes into a highly piezoelectricβphase during electrospinning and enables piezoelectric responses of the filter membrane.Tested with the standard 0.3μm particles,face masks made of the PVA-GLY membrane show an outstanding filtration efficiency of 97%,which remains stable over at least 10 h of high-concentration continuous filtration.Furthermore,we demonstrated the biodegradability of PVA-GLY masks,which can degrade completely within a few weeks,compared to commonly used surgical masks requiring over thirty years to be decomposed.展开更多
Small-scale robots are promising miniaturized devices in biomedicine.Thin-film self-assembly is a commonly used strategy to fabricate tubular small-scale robots.However,the existing methods have limitations like compl...Small-scale robots are promising miniaturized devices in biomedicine.Thin-film self-assembly is a commonly used strategy to fabricate tubular small-scale robots.However,the existing methods have limitations like complex manufacturing processes and limited control of self-assembly behavior.Herein,we present a recently developed laser-guided self-assembly strategy that transforms platinum/gold bilayer thin films into three-dimensional tubular structures.These structures function as chemically actuated,asymmetrically designed small-scale swimmers.Micro-roll structures with customizable geometrical asymmetry are prepared through a precise laserguided rolling process,in which the laser settings can digitally control the rolling behavior because of the pointto-point laser-material interaction.Furthermore,the asfabricated micro-rolls could be directly peeled off the substrate and transferred to the target container by laser irradiation.The specially designed cone-like asymmetric platinum/gold micro-roll can swim forward in the hydrogen peroxide solution by ejecting bubbles from the large open end.The movement of small-scale swimmers in open water can be precisely controlled by adjusting their asymmetry,which is achieved through carefully designed laser scanning paths.The interactions of the asymmetric small-scale swimmers with various boundaries(both fixed and untethered) are systematically investigated and summarized.Micro-roll encapsulation with empty capsules can be integrated into the laser transfer process.The dissolution of capsules and release of small-scale swimmers in aqueous solutions are demonstrated.This research indicates the potential of the one-step laser-guided self-assembly and forward transfer method in manufacturing and encapsulating miniaturized devices.展开更多
Reducing the size of the lamellar structures and increasing the number of twin structures are both effective strategies for enhancing the ductility and fracture toughness ofγ-TiAl alloys.Hot isostatic pressing combin...Reducing the size of the lamellar structures and increasing the number of twin structures are both effective strategies for enhancing the ductility and fracture toughness ofγ-TiAl alloys.Hot isostatic pressing combined with heat treatment is an promising method to optimize the microstructure of TiAl alloys and improve their mechanical properties.However,systematic investigations into the microstructural evolution under high temperature pressure/external stress are limited.In this study,by integrating phase field simulations and CALPHAD thermodynamic database,a unique microstructural response to external stress during aging process is revealed.With the increase of external stress,the size of the lamellar structure initially decreases but then increases,while the number of twin structures initially rises but then decreases,showing nonlinear relationships.An increase in external stress shifts the free energy curves,altering the position of c0(the intersection position between free energies ofα_(2)andγ),which leads to a change in the nucleation mechanism from classical nucleation to pseudo-spinodal decomposition and influences the final microstructure ofγprecipitates.Further simulations indicate a linear correlation between optimal external stress and varying Al content.A deeper analysis indicates that the observed variations in the size and twin structures can be attributed to the interplay among the growth rate of existing variants,the competitive nucleation rates of twinned variants and the redistribution of composition under different external stresses.Our findings provide new insights into optimizing microstructures by pressure/external stress in precipitation processes.展开更多
Utilizing the Discrete Element Method,this research studied the stiffness distribution of gap-graded soils by modifying the conventional static method.By acknowledging the inherent particle property disparity between ...Utilizing the Discrete Element Method,this research studied the stiffness distribution of gap-graded soils by modifying the conventional static method.By acknowledging the inherent particle property disparity between coarser and finer particles,this research differentiates the stiffness distribution of gap-graded soils from the perspective of contact and particle types.Results indicate that particle property disparity significantly influence the small-strain stiffness characteristics,consequently altering the overall stiffness distribution in gap-graded soil specimens.Specifically,with the equivalent coarser particle property,an increase in particle Young's modulus of finer particles results in an augmentation of small-strain stiffness values,alongside an increased stiffness distribution contribution from finer particles.Nevertheless,this study reveals that even with a higher particle Young's modulus of finer particles,the proportion of small-strain stiffness transferred by finer particles remains consistently lower than their volume fraction.Furthermore,the proportion of stiffness transferred by finer particles may fall below their contribution to stress transmission.This investigation accentuates the subtle yet significant effects of particle property variations on small strain stiffness and its subsequent distribution,providing a foundation for advancing the significance of particle property disparities in evaluating soil responses.展开更多
The history of acoustic metamaterials can be traced back to the turn of the 215 century,when the local res-onances of subwavelength structures were leveraged for acoustic properties unavailable in natural materials.[1...The history of acoustic metamaterials can be traced back to the turn of the 215 century,when the local res-onances of subwavelength structures were leveraged for acoustic properties unavailable in natural materials.[1 Over a quarter of 8 century,acoustic metamaterials have continued to thrive as numerous novel acoustic effects have been investigated and realized.[2-6]However,acous-tic metamaterials were entirely passive in their early days,thus indicating that their functionalities were singular and entirely determined at the fabrication stage.Additionally,even at the effective-medium level,such passive metama-terials must obey fundamental laws,such as time reversal symmetry and causality.These limitations can be over-come by employing active components in metamaterial design.Thus,we surveyed the development,functionalities,and implications of active acoustic metamaterials.展开更多
Proton exchange membrane water electrolysis (PEMWE) has garnered significant attention as apivotal technology for converting surplus electricity into hydrogen for long-term storage, as well asfor providing high-purity...Proton exchange membrane water electrolysis (PEMWE) has garnered significant attention as apivotal technology for converting surplus electricity into hydrogen for long-term storage, as well asfor providing high-purity hydrogen for aerospace and high-end manufacturing applications. Withthe ongoing commercialization of PEMWE, advancing iridium-based oxygen evolution reaction(OER) catalysts remains imperative to reconcile stringent requirements for high activity, extendedlongevity, and minimized noble metal loading. The review provides a systematic analysis of theintegrated design of iridium-based catalysts in PEMWE, starting from the fundamentals of OER,including the operation environment of OER catalysts, catalytic performance evaluation withinPEMWE, as well as catalytic and dissolution mechanisms. Subsequently, the catalyst classificationand preparation/characterization techniques are summarized with the focus on the dynamic structure-property relationship. Guided by these understandings, an overview of the design strategiesfor performance enhancement is presented. Specifically, we construct a mathematical frameworkfor cost-performance optimization to offer quantitative guidance for catalyst design. Finally, futureperspectives are proposed, aiming to establish a theoretical framework for rational catalyst design.展开更多
Sensorless control of switched reluctance motors(SRMs) often requires a hybrid mode combining low-speed pulse injection methods and high-speed model-based estimation.However,pulse injection causes unwanted audible noi...Sensorless control of switched reluctance motors(SRMs) often requires a hybrid mode combining low-speed pulse injection methods and high-speed model-based estimation.However,pulse injection causes unwanted audible noises and torque ripples.This article proposes an enhanced model-based sensorless approach to extend downwards the speed range in which sensorless control can work without injection.An inertial phase-locked loop (IPLL) based on a stator flux observer is introduced for position estimation.Compared to the conventional phase-locked loop scheme,the IPLL offers a more robust disturbance rejection capability and thus reduces the flux model errors at lower speeds.Experimental results substantiate the feasibility of the extended low-speed operation using the model-based sensorless control approach.展开更多
The great interest of Fe-N/C based Zn-air batteries and fuel cells intrigues large numbers of studies on modulating the pore structure for fast mass transport and the electronic structure of atomic Fe centers for enha...The great interest of Fe-N/C based Zn-air batteries and fuel cells intrigues large numbers of studies on modulating the pore structure for fast mass transport and the electronic structure of atomic Fe centers for enhancing intrinsic activity for oxygen reduction reaction(ORR).A Zn-assisted strategy herein is developed to synthesize a honeycomb-like micro-nanoscale porous Fe-N/C catalyst with atomic FeN_(3)Cl active sites.Specifically,Zn-guided synthesis of honeycomb-like porous carbon supported ZnO,ZnO-templated assembly of hemin modified ZIF-8 on honeycomb-like carbon and Zn/ZnO-assisted pyrolysis of the ZIF-8 precursor are involved.The synthetic mechanism is revealed by in-situ transmission electron microscopy imaging and in-situ X-ray diffraction analysis.Density functional theory calculations demonstrate FeN_(3)Cl can prominently lower the ORR energy barrier on the Fe centers,greatly facilitating catalytic kinetics.Hence,high ORR performance,including half-wave potentials of 0.81 V in acidic conditions and 0.91 V under alkaline media,is achieved.Besides,Zn-air batteries and H_(2)-O_(2)fuel cells base on the resulting catalyst are investigated,also exhibiting excellent battery/cell performances.This study provides a novel strategy for the preparation of honeycomb-like micro-nanoscale porous single-atom catalysts as well as a significant new insight on the catalytic mechanisms,helping to advance in energy devices.展开更多
One-dimensional perovskites possess unique photoelectric properties that distinguish them from other perovskitetypes, making them a focal point in photoelectric research. In recent years, there has been a significant ...One-dimensional perovskites possess unique photoelectric properties that distinguish them from other perovskitetypes, making them a focal point in photoelectric research. In recent years, there has been a significant surge ininterest surrounding the synthesis and application of one-dimensional anisotropic perovskites, spurred by ad-vancementsin synthesis techniques and notable breakthroughs in novel methodologies and application proper-ties.This article provides a comprehensive review of the progress made in research on one-dimensionalanisotropic perovskites, detailing the synthesis mechanisms and potential pathways for performance enhance-mentin various applications. We highlight the crucial role of controllable synthesis and heterogeneous effect intailoring perovskite properties to boost application efficacy. Initially, this review examines the primary synthesismethods and mechanisms for creating heterogeneously induced one-dimensional anisotropic perovskites, cate-gorizingthem into two main approaches: the classical wet chemical synthesis, which utilizes selective ligands, andthe ligand-free, substrate-assisted method. The precision in controllable synthesis is essential for fabricatingheterogeneous structures, where the synthesized precursor, shape, and surface ligand significantly influence theinterfacial strength of the heterogenic interface. We also discuss the key features that must be improved for high-performanceapplications, exploring how heterogeneous effects can enhance performance and drive the devel-opmentof heterogeneous devices in various applications, such as photodetectors, solar cells, light-emitting di-odes,and photocatalysis. Conclusively, by highlighting the emerging potential and promising opportunitiesoffered by strategic heterogeneous construction, we forecast a dynamic and transformative future for their pro-ductionand application landscapes.展开更多
The oxidative dehydrogenation of propane to propylene using CO_(2)(CO_(2)-ODH)offers a promising route for both propylene production and CO_(2)utilization.In this study,we investigate the effect of alkali metal doping...The oxidative dehydrogenation of propane to propylene using CO_(2)(CO_(2)-ODH)offers a promising route for both propylene production and CO_(2)utilization.In this study,we investigate the effect of alkali metal doping on Pt-based catalysts in CO_(2)-ODH reactions.The optimized 0.1 KPt/S-1 catalyst achieved a high propane conversion of 48.3%,propylene selectivity of 85.5%,and CO_(2)conversion of 19.1%at a low temperature of 500℃with the Pt loading of 0.2 wt%and K loading of 0.1 wt%respectively.Characterization techniques,including high-resolution transmission electron microscope(HR-TEM),CO-diffuse reflectance infrared Fourier transform spectroscopy(CO-DRIFTS),X-ray absorption fine structure(XAFS),and X-ray Photoelectron Spectroscopy(XPS),revealed that the doping of K with Pt led to a strong interaction between potassium and platinum(Pt-KO_(x)cluster).This interaction resulted in a reduction of Pt particle size and a local enrichment of electron density around Pt atoms.These structural modifications improved the anchoring of Pt nanoparticles and enhanced Pt atom dispersion,thereby enhancing the activity of the catalyst and minimizing side reactions.Additionally,pyridine infrared(Py-IR)and temperature-programmed desorption(TPD)studies demonstrated that the prepared0.1 KPt/S-1 catalyst exhibited optimal acidity,which promoted C–H activation and facilitated the efficient adsorption and activation of CO_(2).These dual effects significantly lowered the activation energy for CO_(2)-ODH,enabling efficient dehydrogenation to propylene at a lower temperature of 500℃.This work highlights the critical role of alkali metal doping in modifying the electronic properties of Pt and optimizing catalyst acidity,which collectively contribute to the enhanced performance of the 0.1 KPt/S-1 catalyst.These findings offer valuable insights into the mechanistic pathway of CO_(2)-ODH and provide a foundation for the rational design of high-performance dehydrogenation catalysts.展开更多
Gene expression is regulated by chromatin architecture and epigenetic remodeling in cell homeostasis and pathologies.Histone modifications act as the key factors to modulate the chromatin accessibility.Different histo...Gene expression is regulated by chromatin architecture and epigenetic remodeling in cell homeostasis and pathologies.Histone modifications act as the key factors to modulate the chromatin accessibility.Different histone modifications are strongly associated with the localization of chromatin.Heterochromatin primarily localizes at the nuclear periphery,where it interacts with lamina proteins to suppress gene expression.In this review,we summarize the potential bridges that have regulatory functions of histone modifications in chromatin organization and transcriptional regulation at the nuclear periphery.We use lamina-associated domains(LADs)as examples to elucidate the biological roles of the interactions between histone modifications and nuclear lamina in cell differentiation and development.In the end,we highlight the technologies that are currently used to identify and visualize histone modifications and LADs,which could provide spatiotemporal information for understanding their regulatory functions in gene expression and discovering new targets for diseases.展开更多
Formation control remains a critical challenge in cooperative multi-agent systems,particularly for Unmanned Underwater Vehicles(UUVs).Conventional approaches often suffer from several limitations,including reliance on...Formation control remains a critical challenge in cooperative multi-agent systems,particularly for Unmanned Underwater Vehicles(UUVs).Conventional approaches often suffer from several limitations,including reliance on global information,limited adaptability,high computational complexity,and poor scalability.To address these issues,we propose a novel bio-inspired formation control method for UUV swarms,drawing inspiration from the self-organizing behavior of fish schools.Our method integrates three key components:(1)a coordinated motion strategy without predefined targets that enables individual UUVs to align their movements via simple left or right rotations based solely on local neighbor interactions;(2)a target-directed movement strategy that guides UUVs toward specified regions;and(3)a dispersion control strategy that prevents overcrowding by regulating local spatial distributions.Simulation results confirm that the method achieves robust formation control and efficient area coverage using only local perception.Validation in a 9-UUV simulation environment demonstrates the approach’s flexibility,decentralization,and computational efficiency,making it particularly suitable for large-scale swarms with limited sensing and processing capabilities.展开更多
The development of robust and active oxygen evolution reaction(OER)electrocatalysts is urgently desirable for the widespread implementation of proton exchange membrane water electrolyzers(PEMWE),yet remains a critical...The development of robust and active oxygen evolution reaction(OER)electrocatalysts is urgently desirable for the widespread implementation of proton exchange membrane water electrolyzers(PEMWE),yet remains a critical challenge.We propose a catalyst named U-IrRuO_(x)@IrRu(where“U”denotes“ultrathin”),which features a spontaneously formed amorphous oxide shell that synergistically optimizes the electronic structure and corrosion resistance.Combined experimental and theoretical studies reveal that the oxyphilic Ru-induced electronic modulation weakens Ir-O binding strength,thereby accelerating the rate-determining step of ^(*)OOH formation.In addition,the metallic alloy core functions as an electron reservoir,suppressing excessive oxidation of active sites while ensuring high conductivity.Due to these attributes,the U-IrRuO_(x)@IrRu demonstrates a low overpotential of 230 mV at 10 mA cm^(-2),outperforming commercial IrO_(2)(CM)by 65 mV.When integrated into a PEMWE with an ultra-low Ir loading of 0.25 mg_(Ir)cm^(-2),it delivers an industrial current density of 2 A cm^(-2)at 1.74 V and 3 A cm^(-2)at 1.836 V,surpassing the U.S.Department of Energy(DOE)2025 target.More impressively,the U-IrRuOx@IrRubased electrolyzer can stably operate for over 550 h,with an extremely low decay rate of 7.52μV h^(-1),corresponding to a predicted lifespan of 23,000 h with 90%performance retention.展开更多
Long-duration energy storage has become critical for renewable energy integration.While redox flow batteries,especially vanadium-based systems,are scaling up in capacity,their performance at the stack level remains in...Long-duration energy storage has become critical for renewable energy integration.While redox flow batteries,especially vanadium-based systems,are scaling up in capacity,their performance at the stack level remains insufficiently optimized,demanding more profound mechanistic studies and engineering refinements.To address the difficulties in resolving the flow inhomogeneity at the stack scale,this study establishes a multi-physics field coupling model and analyzes the pressure distributions,flow rate differences,active substance concentration,and electrochemical characteristics.The results show that the uneven cell pressure distribution is a key factor affecting the consistency of the system performance,and the increase in the flow rate improves the reactant homogeneity,with both the average concentration and the uniformity factor increasing with the flow rate.In contrast,high current densities lead to an increased imbalance between electrochemical depletion and reactant replenishment,resulting in a significant decrease in reactant concentration in the under-ribs region.In addition,a higher flow rate can expand the high-current-density region where the stack operates efficiently.This study provides a theoretical basis for optimizing the design of the stack components.展开更多
A wastewater evaporation-desalination pretreatment method was introduced to remove the Na+ and K+ salts in volatile organic compounds (VOCs) wastewater before it was fed into the incinerator. VOCs in the wastewater we...A wastewater evaporation-desalination pretreatment method was introduced to remove the Na+ and K+ salts in volatile organic compounds (VOCs) wastewater before it was fed into the incinerator. VOCs in the wastewater were volatilized in the evaporation system and then the vapor was combusted in an incinerator. Simulated phenol wastewater containing sodium chloride was evaporated and concentrated and sodium chloride was crystallized in different parameters. The experimental results showed that the higher initial concentration of sodium chloride increases the ratio of volatilization of VOCs, which was due to the effect of “salting out” (a decrease in the solubility of the nonelectrolyte in the solution, or more rigorously, an increase in its activity coef-ficient, caused by the salt addition (Furter and Cook, 1967)). When evaporation speed was increased from 1.67 ml/min to 2.73 ml/min, the total removal coefficient of sodium chloride was about 99.88%～99.99%. This pretreatment procedure eliminates the slag phenomenon caused by Na+ and K+ salts during wastewater incineration, so the incinerator could operate continuously, and the wastewater evaporation could increase the heat value of wastewater, and the operation cost would be reduced.展开更多
Ellipticity as the underlying mechanism for instabilities of physical systems is highlighted in the study of model nonlinear evolution equations with dissipation and the study of phase transition in Van der Waals flui...Ellipticity as the underlying mechanism for instabilities of physical systems is highlighted in the study of model nonlinear evolution equations with dissipation and the study of phase transition in Van der Waals fluid. Interesting results include spiky solutions, chaotic behavior in the context of partial differential equations, as well as the nucleation process due to ellipticity in phase transition.展开更多
基金supported by the National Key R&D Program of China,No.2023YFC2509700the Beijing Natural Science Foundation-Haidian Original Innovation Joint Fund,No.L232141the Research and Application of Clinical Characteristic Diagnosis and Treatment Program,No.Z221100007422019(all to WD)。
文摘Spinal cord injury is a severe neurological disorder;however,current treatment methods often fail to restore nerve function effectively.Spinal cord stimulation via electrical signals is a promising therapeutic modality for spinal cord injury.Based on similar principles,this review aims to explore the potential of optical and acoustic neuromodulation techniques,emphasizing their benefits in the context of spinal cord injury.Photoacoustic imaging,renowned for its noninvasive nature,high-resolution capabilities,and cost-effectiveness,is well recognized for its role in early diagnosis,dynamic monitoring,and surgical guidance in stem cell therapies for spinal cord injury.Moreover,photoacoustodynamic therapy offers multiple pathways for tissue regeneration.Optogenetics and sonogenetics use genetic engineering to achieve precise neuronal activation,while photoacoustoelectric therapy leverages photovoltaic materials for electrical modulation of the nervous system,introducing an innovative paradigm for nerve system disorder management.Collectively,these advancements represent a transformative shift in the diagnosis and treatment of spinal cord injury,with the potential to significantly enhance nerve function remodeling and improve patient outcomes.
基金supported by the National Natural Science Foundation of China(Nos.U21B2053,52071114,52001100,and 523B2010)Outstanding Youth Project of Natural Science Foundation of Heilongjiang Province(No.YQ2023E008)+1 种基金Young Elite Scientists Sponsorship Program by CAST(NO.2021QNRC001)Heilongjiang Touyan Team Program.
文摘Silicide coatings have proven to be promising for improving the high-temperature oxidation resistance of niobium alloy.However,the long-term protective property of single silicide coating remains a long-time endeavor due to the deficiency of oxygen-consuming phases,as well as the self-healing ability of the protective layer.Herein,a silicide-based composite coating is constructed on niobium alloy by incor-poration of nano-SiC particles for enhancing the high-temperature oxidation resistance.Isothermal oxi-dation results at 1250℃ for 50 h indicate that NbSi_(2)/Nb_(2)O_(5)-SiO_(2)/SiC multilayer coated sample with a low mass gain of 2.49 mg/cm^(2) shows an improved oxidation resistance compared with NbSi_(2) coating(6.49 mg/cm^(2)).The enhanced high-temperature antioxidant performance of NbSi_(2)/Nb_(2)O_(5)-SiO_(2)/SiC multi-layer coating is mainly attributed to the formation of the protective SiO_(2) self-healing film and the high-temperature diffusion behavior of NbSi_(2)/substrate.
基金supported by the National Science Fund for Distinguished Young Scholars of China(Grant No.42225702)the National Natural Science Foundation of China(Grant Nos.42461160266 and 52379106).
文摘Geo-interfaces refer to the contact surfaces between multiple media within geological strata,as well as the transition zones that regulate the migration of three-phase matter,changes in physical states,and the deformation and stability of rock and soil masses.Owing to the combined effects of natural factors and human activities,geo-interfaces play crucial roles in the emergence,propagation,and triggering of geological disasters.Over the past three decades,the material point method(MPM)has emerged as a preferred approach for addressing large deformation problems and simulating soil-water-structure interactions,making it an ideal tool for analyzing geo-interface behaviors.In this review,we offer a systematic summary of the basic concepts,classifications,and main characteristics of the geo-interface,and provide a comprehensive overview of recent advances and developments in simulating geo-interface using the MPM.We further present a brief description of various MPMs for modeling different types of geo-interfaces in geotechnical engineering applications and highlight the existing limitations and future research directions.This study aims to facilitate innovative applications of the MPM in modeling complex geo-interface problems,providing a reference for geotechnical practitioners and researchers.
基金support provided by the research funds from the Hong Kong Research Grants Council(Grant Nos.16206623,N_HKUST603/22,and C6006-20G).
文摘Correctly tracking the evolution of spatial heterogeneity of local degree of saturation(Sr)in unsaturated soils is essential to explain the seepage phenomenon,which is crucial to assessing slope stability.Several methods exist for quantifying the heterogeneity of local S_(r).However,a comprehensive comparison of these methods in terms of accuracy,relative advantages,and disadvantages is currently lacking.This paper presents a comparative analysis of local Sr obtained at multiple scales,ranging from the element scale to the slice,representative element volume(REV),pore,and voxel scales.The spatial heterogeneity of Sr in an unsaturated glass beads specimen at different matric suctions was visualised and quantified by multiscale X-ray micro-focus computed tomography image-based analysis methods.Local Sr obtained at different scales displayed a comparable trend along the sample depth,yet the REV-scale method showed a much scattered and discontinuous distribution.In contrast,the pore-scale method detected a distinct two-clustered,bimodal distribution of S_(r).The pore-scale method has the highest integrated resolution,as it has the highest spatial resolution(i.e.number of data points)and provides more information(i.e.number of extractable physical parameters).This method thus provides a more effective approach for tracking the spatial heterogeneity of S_(r).Based on this method,pore-scale water retention curves were determined,offering new quantitative means to characterise pore water heterogeneity and explainwater drainage processes such as hysteresis at the pore scale.
基金supported by General Research Grants (GRF Project No. 11212021 and No. 11210822) from the Research Grants Council of the Hong Kong Special Administrative Regionthe Innovation and Technology Fund (Project No. ITS/065/20GHP/096/19SZ) from Innovation and Technology Commission of Hong Kong Special Administrative Region
文摘The mass discarding face masks has caused severe environmental problems during and after the COVID-19 pandemic.To reduce waste and minimize environmental impact,we present a new face mask featuring selfcharging extended service time and fully biodegradable materials.To extend the effective service time,we need to supplement the lost electric charge of the electret layer of face masks,for which task we propose to use the piezoelectric effect and generate electricity from breathing motions.However,existing piezoelectric materials are either toxic,impermeable,rigid,costly,or non-degradable.We synthesize a fully biodegradable piezoelectric membrane composed of polyvinyl alcohol(PVA)and glycine(GLY)via the electrospinning process.Parameters are accurately controlled to ensure that glycine crystallizes into a highly piezoelectricβphase during electrospinning and enables piezoelectric responses of the filter membrane.Tested with the standard 0.3μm particles,face masks made of the PVA-GLY membrane show an outstanding filtration efficiency of 97%,which remains stable over at least 10 h of high-concentration continuous filtration.Furthermore,we demonstrated the biodegradability of PVA-GLY masks,which can degrade completely within a few weeks,compared to commonly used surgical masks requiring over thirty years to be decomposed.
基金financially supported by the Hong Kong Research Grants Council(Nos.25201620,JLFS/P-603/24 and C6001-22Y)the Hong Kong Innovation Technology Commission(ITC)(No.MHP/060/21)+1 种基金the Hong Kong Branch of the Chinese National Engineering Research Center for Tissue Restoration and Reconstruction(No.ITC-CNERC14SC01)the State Key Laboratory of Advanced Displays and Optoelectronics Technologies,The Hong Kong University of Science and Technology
文摘Small-scale robots are promising miniaturized devices in biomedicine.Thin-film self-assembly is a commonly used strategy to fabricate tubular small-scale robots.However,the existing methods have limitations like complex manufacturing processes and limited control of self-assembly behavior.Herein,we present a recently developed laser-guided self-assembly strategy that transforms platinum/gold bilayer thin films into three-dimensional tubular structures.These structures function as chemically actuated,asymmetrically designed small-scale swimmers.Micro-roll structures with customizable geometrical asymmetry are prepared through a precise laserguided rolling process,in which the laser settings can digitally control the rolling behavior because of the pointto-point laser-material interaction.Furthermore,the asfabricated micro-rolls could be directly peeled off the substrate and transferred to the target container by laser irradiation.The specially designed cone-like asymmetric platinum/gold micro-roll can swim forward in the hydrogen peroxide solution by ejecting bubbles from the large open end.The movement of small-scale swimmers in open water can be precisely controlled by adjusting their asymmetry,which is achieved through carefully designed laser scanning paths.The interactions of the asymmetric small-scale swimmers with various boundaries(both fixed and untethered) are systematically investigated and summarized.Micro-roll encapsulation with empty capsules can be integrated into the laser transfer process.The dissolution of capsules and release of small-scale swimmers in aqueous solutions are demonstrated.This research indicates the potential of the one-step laser-guided self-assembly and forward transfer method in manufacturing and encapsulating miniaturized devices.
基金supported by the National Key Research and Development Program of China(No.2021YFB3702603)the Outstanding Youth Fund of Shaanxi Province(No.2024JC-JCQN-45)+3 种基金the Scientist+Engineer Teams in Shaanxi’s Qin Chuangyuan Initiative(No.2023KXJ-183)the National Natural Science Foundation of China(No.52171012)111 Project(No.BP2018008),the GHfundA(No.202302019461)“H2”High-Performance Cluster.
文摘Reducing the size of the lamellar structures and increasing the number of twin structures are both effective strategies for enhancing the ductility and fracture toughness ofγ-TiAl alloys.Hot isostatic pressing combined with heat treatment is an promising method to optimize the microstructure of TiAl alloys and improve their mechanical properties.However,systematic investigations into the microstructural evolution under high temperature pressure/external stress are limited.In this study,by integrating phase field simulations and CALPHAD thermodynamic database,a unique microstructural response to external stress during aging process is revealed.With the increase of external stress,the size of the lamellar structure initially decreases but then increases,while the number of twin structures initially rises but then decreases,showing nonlinear relationships.An increase in external stress shifts the free energy curves,altering the position of c0(the intersection position between free energies ofα_(2)andγ),which leads to a change in the nucleation mechanism from classical nucleation to pseudo-spinodal decomposition and influences the final microstructure ofγprecipitates.Further simulations indicate a linear correlation between optimal external stress and varying Al content.A deeper analysis indicates that the observed variations in the size and twin structures can be attributed to the interplay among the growth rate of existing variants,the competitive nucleation rates of twinned variants and the redistribution of composition under different external stresses.Our findings provide new insights into optimizing microstructures by pressure/external stress in precipitation processes.
基金Financial supports from the PolyU Distinguished Postdoctoral Fellowship Scheme are highly appreciatedsupported by the National Natural Science Foundation of China (Grant No.52201008)the Fundamental Research Funds for the Central Universities,the State Key Laboratory of Particle Detection and Electronics (Grant No.SKLPDE-KF-202311).
文摘Utilizing the Discrete Element Method,this research studied the stiffness distribution of gap-graded soils by modifying the conventional static method.By acknowledging the inherent particle property disparity between coarser and finer particles,this research differentiates the stiffness distribution of gap-graded soils from the perspective of contact and particle types.Results indicate that particle property disparity significantly influence the small-strain stiffness characteristics,consequently altering the overall stiffness distribution in gap-graded soil specimens.Specifically,with the equivalent coarser particle property,an increase in particle Young's modulus of finer particles results in an augmentation of small-strain stiffness values,alongside an increased stiffness distribution contribution from finer particles.Nevertheless,this study reveals that even with a higher particle Young's modulus of finer particles,the proportion of small-strain stiffness transferred by finer particles remains consistently lower than their volume fraction.Furthermore,the proportion of stiffness transferred by finer particles may fall below their contribution to stress transmission.This investigation accentuates the subtle yet significant effects of particle property variations on small strain stiffness and its subsequent distribution,providing a foundation for advancing the significance of particle property disparities in evaluating soil responses.
文摘The history of acoustic metamaterials can be traced back to the turn of the 215 century,when the local res-onances of subwavelength structures were leveraged for acoustic properties unavailable in natural materials.[1 Over a quarter of 8 century,acoustic metamaterials have continued to thrive as numerous novel acoustic effects have been investigated and realized.[2-6]However,acous-tic metamaterials were entirely passive in their early days,thus indicating that their functionalities were singular and entirely determined at the fabrication stage.Additionally,even at the effective-medium level,such passive metama-terials must obey fundamental laws,such as time reversal symmetry and causality.These limitations can be over-come by employing active components in metamaterial design.Thus,we surveyed the development,functionalities,and implications of active acoustic metamaterials.
文摘Proton exchange membrane water electrolysis (PEMWE) has garnered significant attention as apivotal technology for converting surplus electricity into hydrogen for long-term storage, as well asfor providing high-purity hydrogen for aerospace and high-end manufacturing applications. Withthe ongoing commercialization of PEMWE, advancing iridium-based oxygen evolution reaction(OER) catalysts remains imperative to reconcile stringent requirements for high activity, extendedlongevity, and minimized noble metal loading. The review provides a systematic analysis of theintegrated design of iridium-based catalysts in PEMWE, starting from the fundamentals of OER,including the operation environment of OER catalysts, catalytic performance evaluation withinPEMWE, as well as catalytic and dissolution mechanisms. Subsequently, the catalyst classificationand preparation/characterization techniques are summarized with the focus on the dynamic structure-property relationship. Guided by these understandings, an overview of the design strategiesfor performance enhancement is presented. Specifically, we construct a mathematical frameworkfor cost-performance optimization to offer quantitative guidance for catalyst design. Finally, futureperspectives are proposed, aiming to establish a theoretical framework for rational catalyst design.
基金supported in part by the National Natural Science Foundation of China 52307069in part by 2024 Tertiary Education Scientific Research Project of Guangzhou Municipal Education Bureau under Grant2024312176in part by the Project of Hetao Shenzhen-Hong Kong Science and Technology Innovation Cooperation Zone under Grant HZQB-KCZYB-2020083。
文摘Sensorless control of switched reluctance motors(SRMs) often requires a hybrid mode combining low-speed pulse injection methods and high-speed model-based estimation.However,pulse injection causes unwanted audible noises and torque ripples.This article proposes an enhanced model-based sensorless approach to extend downwards the speed range in which sensorless control can work without injection.An inertial phase-locked loop (IPLL) based on a stator flux observer is introduced for position estimation.Compared to the conventional phase-locked loop scheme,the IPLL offers a more robust disturbance rejection capability and thus reduces the flux model errors at lower speeds.Experimental results substantiate the feasibility of the extended low-speed operation using the model-based sensorless control approach.
基金supported by the National Natural Science Foundation of China(52372049)Yunnan Fundamental Research Projects(202301AW070016)+2 种基金China Postdoctoral Science Foundation(Certificate Number:2023M743573)Postdoctoral Fellowship Program of CPSF(GZC20232744)Project of Xingdian Talent Support Plan.
文摘The great interest of Fe-N/C based Zn-air batteries and fuel cells intrigues large numbers of studies on modulating the pore structure for fast mass transport and the electronic structure of atomic Fe centers for enhancing intrinsic activity for oxygen reduction reaction(ORR).A Zn-assisted strategy herein is developed to synthesize a honeycomb-like micro-nanoscale porous Fe-N/C catalyst with atomic FeN_(3)Cl active sites.Specifically,Zn-guided synthesis of honeycomb-like porous carbon supported ZnO,ZnO-templated assembly of hemin modified ZIF-8 on honeycomb-like carbon and Zn/ZnO-assisted pyrolysis of the ZIF-8 precursor are involved.The synthetic mechanism is revealed by in-situ transmission electron microscopy imaging and in-situ X-ray diffraction analysis.Density functional theory calculations demonstrate FeN_(3)Cl can prominently lower the ORR energy barrier on the Fe centers,greatly facilitating catalytic kinetics.Hence,high ORR performance,including half-wave potentials of 0.81 V in acidic conditions and 0.91 V under alkaline media,is achieved.Besides,Zn-air batteries and H_(2)-O_(2)fuel cells base on the resulting catalyst are investigated,also exhibiting excellent battery/cell performances.This study provides a novel strategy for the preparation of honeycomb-like micro-nanoscale porous single-atom catalysts as well as a significant new insight on the catalytic mechanisms,helping to advance in energy devices.
基金supported by the National Natural Science Foundation of China(22272065)the Natural Science Foundation of Jiangsu Province(BK20211530)+1 种基金the Fundamental Research Funds for the Central Universities(JUSRP62218)the Key Research and Development Special Project of Yi'chun City,Jiangxi Province,China(2023ZDYFZX06).
文摘One-dimensional perovskites possess unique photoelectric properties that distinguish them from other perovskitetypes, making them a focal point in photoelectric research. In recent years, there has been a significant surge ininterest surrounding the synthesis and application of one-dimensional anisotropic perovskites, spurred by ad-vancementsin synthesis techniques and notable breakthroughs in novel methodologies and application proper-ties.This article provides a comprehensive review of the progress made in research on one-dimensionalanisotropic perovskites, detailing the synthesis mechanisms and potential pathways for performance enhance-mentin various applications. We highlight the crucial role of controllable synthesis and heterogeneous effect intailoring perovskite properties to boost application efficacy. Initially, this review examines the primary synthesismethods and mechanisms for creating heterogeneously induced one-dimensional anisotropic perovskites, cate-gorizingthem into two main approaches: the classical wet chemical synthesis, which utilizes selective ligands, andthe ligand-free, substrate-assisted method. The precision in controllable synthesis is essential for fabricatingheterogeneous structures, where the synthesized precursor, shape, and surface ligand significantly influence theinterfacial strength of the heterogenic interface. We also discuss the key features that must be improved for high-performanceapplications, exploring how heterogeneous effects can enhance performance and drive the devel-opmentof heterogeneous devices in various applications, such as photodetectors, solar cells, light-emitting di-odes,and photocatalysis. Conclusively, by highlighting the emerging potential and promising opportunitiesoffered by strategic heterogeneous construction, we forecast a dynamic and transformative future for their pro-ductionand application landscapes.
基金supported by the National Key Research and Development Program of China(2022YFE0208300)the Natural Science Foundation of China(22078354)。
文摘The oxidative dehydrogenation of propane to propylene using CO_(2)(CO_(2)-ODH)offers a promising route for both propylene production and CO_(2)utilization.In this study,we investigate the effect of alkali metal doping on Pt-based catalysts in CO_(2)-ODH reactions.The optimized 0.1 KPt/S-1 catalyst achieved a high propane conversion of 48.3%,propylene selectivity of 85.5%,and CO_(2)conversion of 19.1%at a low temperature of 500℃with the Pt loading of 0.2 wt%and K loading of 0.1 wt%respectively.Characterization techniques,including high-resolution transmission electron microscope(HR-TEM),CO-diffuse reflectance infrared Fourier transform spectroscopy(CO-DRIFTS),X-ray absorption fine structure(XAFS),and X-ray Photoelectron Spectroscopy(XPS),revealed that the doping of K with Pt led to a strong interaction between potassium and platinum(Pt-KO_(x)cluster).This interaction resulted in a reduction of Pt particle size and a local enrichment of electron density around Pt atoms.These structural modifications improved the anchoring of Pt nanoparticles and enhanced Pt atom dispersion,thereby enhancing the activity of the catalyst and minimizing side reactions.Additionally,pyridine infrared(Py-IR)and temperature-programmed desorption(TPD)studies demonstrated that the prepared0.1 KPt/S-1 catalyst exhibited optimal acidity,which promoted C–H activation and facilitated the efficient adsorption and activation of CO_(2).These dual effects significantly lowered the activation energy for CO_(2)-ODH,enabling efficient dehydrogenation to propylene at a lower temperature of 500℃.This work highlights the critical role of alkali metal doping in modifying the electronic properties of Pt and optimizing catalyst acidity,which collectively contribute to the enhanced performance of the 0.1 KPt/S-1 catalyst.These findings offer valuable insights into the mechanistic pathway of CO_(2)-ODH and provide a foundation for the rational design of high-performance dehydrogenation catalysts.
基金financially supported by the National Natural Science Foundation of China(32100450 and 32471370 to Q.P.,12372302 to J.Q.)the Guangdong Pearl River Talent Program(2021QN02Y781 to Q.P.)the Evident&Shenzhen Bay Laboratory Joint Optical Microscopic Imaging Technology Development Program(S234602004-1 to Q.P.).
文摘Gene expression is regulated by chromatin architecture and epigenetic remodeling in cell homeostasis and pathologies.Histone modifications act as the key factors to modulate the chromatin accessibility.Different histone modifications are strongly associated with the localization of chromatin.Heterochromatin primarily localizes at the nuclear periphery,where it interacts with lamina proteins to suppress gene expression.In this review,we summarize the potential bridges that have regulatory functions of histone modifications in chromatin organization and transcriptional regulation at the nuclear periphery.We use lamina-associated domains(LADs)as examples to elucidate the biological roles of the interactions between histone modifications and nuclear lamina in cell differentiation and development.In the end,we highlight the technologies that are currently used to identify and visualize histone modifications and LADs,which could provide spatiotemporal information for understanding their regulatory functions in gene expression and discovering new targets for diseases.
基金supported by The Special Fund for Basic Scientific Research for Liaoning Provincial Governed Universities(2024JBZDZ004)Fishery Central Financial Support Project of Liaoning Province(2023)+5 种基金Liaoning Province Key Research and Development Plan(2023JH26/10200015)Natural Science Foundation of Liaoning Province(2020-KF-12-09)The Liaoning Provincial Education Commission Fund(LJKZ0730,QL202016)Applied Basic Research Project of Science and Technology Commission of Liaoning Province(2022JH2/101300187)Open Fund of Key Laboratory of Environmental Control Aquaculture of Ministry of Education(Dalian Ocean University)(202219)Liaoning Province Science and Technology Plan Joint Program(2024JH2/102600083).
文摘Formation control remains a critical challenge in cooperative multi-agent systems,particularly for Unmanned Underwater Vehicles(UUVs).Conventional approaches often suffer from several limitations,including reliance on global information,limited adaptability,high computational complexity,and poor scalability.To address these issues,we propose a novel bio-inspired formation control method for UUV swarms,drawing inspiration from the self-organizing behavior of fish schools.Our method integrates three key components:(1)a coordinated motion strategy without predefined targets that enables individual UUVs to align their movements via simple left or right rotations based solely on local neighbor interactions;(2)a target-directed movement strategy that guides UUVs toward specified regions;and(3)a dispersion control strategy that prevents overcrowding by regulating local spatial distributions.Simulation results confirm that the method achieves robust formation control and efficient area coverage using only local perception.Validation in a 9-UUV simulation environment demonstrates the approach’s flexibility,decentralization,and computational efficiency,making it particularly suitable for large-scale swarms with limited sensing and processing capabilities.
基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA 0400301)the National Key R&D Program of China(No.2022YFB4002000)+3 种基金the National Natural Science Foundation of China(No.22232004)the Instrument Developing Project of the Chinese Academy of Sciencesthe Jilin Province Development and Reform Commission Program(2023C032-6)the Jilin Province Science and Technology Development Program(No.20240302002ZD,20240101019JC and 20210502002ZP)for financial support。
文摘The development of robust and active oxygen evolution reaction(OER)electrocatalysts is urgently desirable for the widespread implementation of proton exchange membrane water electrolyzers(PEMWE),yet remains a critical challenge.We propose a catalyst named U-IrRuO_(x)@IrRu(where“U”denotes“ultrathin”),which features a spontaneously formed amorphous oxide shell that synergistically optimizes the electronic structure and corrosion resistance.Combined experimental and theoretical studies reveal that the oxyphilic Ru-induced electronic modulation weakens Ir-O binding strength,thereby accelerating the rate-determining step of ^(*)OOH formation.In addition,the metallic alloy core functions as an electron reservoir,suppressing excessive oxidation of active sites while ensuring high conductivity.Due to these attributes,the U-IrRuO_(x)@IrRu demonstrates a low overpotential of 230 mV at 10 mA cm^(-2),outperforming commercial IrO_(2)(CM)by 65 mV.When integrated into a PEMWE with an ultra-low Ir loading of 0.25 mg_(Ir)cm^(-2),it delivers an industrial current density of 2 A cm^(-2)at 1.74 V and 3 A cm^(-2)at 1.836 V,surpassing the U.S.Department of Energy(DOE)2025 target.More impressively,the U-IrRuOx@IrRubased electrolyzer can stably operate for over 550 h,with an extremely low decay rate of 7.52μV h^(-1),corresponding to a predicted lifespan of 23,000 h with 90%performance retention.
基金supported by National Natural Science Foundation of China(No.524B2078,12426307,51906203)Guangdong Major Project of Basic and Applied Basic Research(2023B0303000002)+6 种基金Guangdong Basic and Applied Basic Research Foundation(2023B1515120005)Natural Science Foundation of Shenzhen(JCYJ20241202125327036,JCYJ20240813100103005)Shenzhen Engineering Research Center of Redox Flow Battery for Energy Storage(XMHT20230208003)Research Project on Medium-and Long-Duration Flow Battery Energy Storage Technology(2024KJTW0015)China Association for Science and Technology(OR2308010)High level of special funds(G03034K001)supported by the Center for Computational Science and Engineering at the Southern University of Science and Technology.
文摘Long-duration energy storage has become critical for renewable energy integration.While redox flow batteries,especially vanadium-based systems,are scaling up in capacity,their performance at the stack level remains insufficiently optimized,demanding more profound mechanistic studies and engineering refinements.To address the difficulties in resolving the flow inhomogeneity at the stack scale,this study establishes a multi-physics field coupling model and analyzes the pressure distributions,flow rate differences,active substance concentration,and electrochemical characteristics.The results show that the uneven cell pressure distribution is a key factor affecting the consistency of the system performance,and the increase in the flow rate improves the reactant homogeneity,with both the average concentration and the uniformity factor increasing with the flow rate.In contrast,high current densities lead to an increased imbalance between electrochemical depletion and reactant replenishment,resulting in a significant decrease in reactant concentration in the under-ribs region.In addition,a higher flow rate can expand the high-current-density region where the stack operates efficiently.This study provides a theoretical basis for optimizing the design of the stack components.
文摘A wastewater evaporation-desalination pretreatment method was introduced to remove the Na+ and K+ salts in volatile organic compounds (VOCs) wastewater before it was fed into the incinerator. VOCs in the wastewater were volatilized in the evaporation system and then the vapor was combusted in an incinerator. Simulated phenol wastewater containing sodium chloride was evaporated and concentrated and sodium chloride was crystallized in different parameters. The experimental results showed that the higher initial concentration of sodium chloride increases the ratio of volatilization of VOCs, which was due to the effect of “salting out” (a decrease in the solubility of the nonelectrolyte in the solution, or more rigorously, an increase in its activity coef-ficient, caused by the salt addition (Furter and Cook, 1967)). When evaporation speed was increased from 1.67 ml/min to 2.73 ml/min, the total removal coefficient of sodium chloride was about 99.88%～99.99%. This pretreatment procedure eliminates the slag phenomenon caused by Na+ and K+ salts during wastewater incineration, so the incinerator could operate continuously, and the wastewater evaporation could increase the heat value of wastewater, and the operation cost would be reduced.
文摘Ellipticity as the underlying mechanism for instabilities of physical systems is highlighted in the study of model nonlinear evolution equations with dissipation and the study of phase transition in Van der Waals fluid. Interesting results include spiky solutions, chaotic behavior in the context of partial differential equations, as well as the nucleation process due to ellipticity in phase transition.
