The reactive materials filled structure(RMFS)is a structural penetrator that replaces high explosive(HE)with reactive materials,presenting a novel self-distributed initiation,multiple deflagrations behavior during pen...The reactive materials filled structure(RMFS)is a structural penetrator that replaces high explosive(HE)with reactive materials,presenting a novel self-distributed initiation,multiple deflagrations behavior during penetrating multi-layered plates,and generating a multipeak overpressure behind the plates.Here analytical models of RMFS self-distributed energy release and equivalent deflagration are developed.The multipeak overpressure formation model based on the single deflagration overpressure expression was promoted.The impact tests of RMFS on multi-layered plates at 584 m/s,616 m/s,and819 m/s were performed to validate the analytical model.Further,the influence of a single overpressure peak and time intervals versus impact velocity is discussed.The analysis results indicate that the deflagration happened within 20.68 mm behind the plate,the initial impact velocity and plate thickness are the crucial factors that dominate the self-distributed multipeak overpressure effect.Three formation patterns of multipeak overpressure are proposed.展开更多
Reactive compatibilization has been widely applied to enhance the compatibility of polymer blends,thereby improving their mechanical properties.However,it generally reduces the chain mobility and regularity,often lead...Reactive compatibilization has been widely applied to enhance the compatibility of polymer blends,thereby improving their mechanical properties.However,it generally reduces the chain mobility and regularity,often leading to slower polymer crystallization.Here,we demonstrate that reactive compatibilization in poly(lactic acid)/poly(butylene adipate-co-terephthalate)(PLA/PBAT)blends unexpectedly promotes PLA matrix crystallization during injection molding,in contrast to the retarded kinetics observed in differential scanning calorimetry isothermal crystallization studies.The phase morphology,rheological behavior,and crystalline structure were systematically analyzed to elucidate markedly different crystallization kinetics under static and shear fields.The potential mechanism underlying crystallization enhancement is attributed to PBAT domain refinement and viscosity increase induced by reactive compatibilization,which,under shear flow,create favorable conditions for crystallization by enhancing PBAT fibril nucleation and retarding the relaxation of oriented PLA chains.This study offers new perspectives on the effect of reactive compatibilization on the polymer crystallization behavior.展开更多
Hybrid commutation converters(HCCs)utilizing reverse-blocking integrated gate commutation thyristors(IGCTs)have gained significant attention due to their immunity to commutation failure.Leveraging the recovery enhance...Hybrid commutation converters(HCCs)utilizing reverse-blocking integrated gate commutation thyristors(IGCTs)have gained significant attention due to their immunity to commutation failure.Leveraging the recovery enhancement characteristics of IGCTs,HCCs demonstrate superior performance at reduced extinction angles,thereby minimizing reactive power consumption.This study presents a comprehensive investigation into reactive power control strategies for HCCs operating at small extinction angles.First,the topological configuration and commutation principle of HCC are elucidated.Subsequently,the mechanism of HCC reactive power control is analyzed,and a reactive power control strategy is proposed by combining the converter transformer taps with extinction angles.Moreover,the relationship between transformer taps and reactive power exchange under different rated extinction angles is calculated,and the theoretically rated extinction angle is proposed.Finally,to validate the proposed control strategy,a four-terminal ultra-high voltage direct current power grid incorporating HCC technology is modeled and sim-ulated using PSCAD/EMTDC.The simulation results demonstrate that the proposed strategy effectively supports AC systems by reducing reactive power absorption in HCCs,while simultaneously exhibiting enhanced reli-ability and economic efficiency.展开更多
The transient synchronization stability of grid-forming converters(GFMCs)is significantly challenged under grid voltage sags.Continuous efforts have been devoted to analyzing the GFMC transient stability,with limited ...The transient synchronization stability of grid-forming converters(GFMCs)is significantly challenged under grid voltage sags.Continuous efforts have been devoted to analyzing the GFMC transient stability,with limited attention paid to the impacts of control loop dynamics.However,the complex control dynamics,especially the interactions between the active/reactive power control loops and the current saturation process(CSP),are crucial for accurately describing the transient behavior and evaluating the stability.Thus,in this study,a new large-signal GFMC model is established,considering the reactive power control(RPC)with different kinds of controllers and the CSP simultaneously.It is revealed that GFMC does not switch to the current-limited mode immediately,and the dynamics of RPC further affect the transient behavior before the current limiting significantly.Hence,the complex control dynamics can alter the mode switching point of current saturation,thereby increasing the risk of loss of synchronization(LOS).Based on the above findings,comprehensive comparisons of typical RPC controllers are presented to facilitate practical engineering applications.A unified stability enhancement method is proposed for solving the problem of LOS.Finally,experiments validate the correctness of the analysis and the effectiveness of the proposed control strategy.展开更多
Rubber-toughened thermoplastic materials have become ubiquitous in modern society owing to their lightweight nature and desirable combination of advantageous performances.Despite the ever-increasing demand,the develop...Rubber-toughened thermoplastic materials have become ubiquitous in modern society owing to their lightweight nature and desirable combination of advantageous performances.Despite the ever-increasing demand,the development of polymer alloys that are lightweight,high-strength,and high-toughness remains an ongoing challenge.Inspired by the unique“salami”microstructure from commercial acrylonitrile butadiene styrene copolymer(ABS)and high-impact polystyrene(HIPS),a facile approach was developed to overcome the trade-off between enhancing the toughness and rigidity of fully polymer-based alloys by virtue of elastomeric salami particles.This strategy entails pre-grafting rigid poly(lactic acid)(PLLA)chains with glycidyl methacrylate-grafted octene ethylene copolymer(POE-g-GMA)using complementary reactive groups.It can be envisaged that the PLLA grafts featuring strong incompatibility with polypropylene(PP)remain fixed in elastomer phase upon the subsequent melt compounding,facilitating the in situ formation of“hard core(PLLA)-soft shell(polyolefin elastomer,POE)”particles in polypropylene(PP)matrix.The all-polymer alloys containing elastomeric salami particles demonstrated unprecedented performance combinations,including upper notched impact strengths(56.8 kJ/m2),even higher tensile strength(36.8 MPa),and Young’s modulus(0.93 GPa)than that of the PP matrix.Furthermore,these materials are lightweight without the incorporation of reinforcing nano-fillers,which is competitive with industrial engineering plastics.It is highly anticipated that this universal and highly efficient protocol will be appropriate for arbitrary rubber toughened/reinforced systems,offering a paradigm in the design of advanced all-polymer alloys.展开更多
Biochar and zero-valent iron are promising materials for the removal of trichloroethylene(TCE)from groundwater,but further research is still required on the synergistic mechanism and hydraulic performance in the perme...Biochar and zero-valent iron are promising materials for the removal of trichloroethylene(TCE)from groundwater,but further research is still required on the synergistic mechanism and hydraulic performance in the permeable reactive barriers(PRBs)with biochar-iron composites.In this work,biochar-iron composites were synthesized by two different methods,and subjected to the microscopic analysis,batch experiments and the PRB’s model tests.The results indicated that the removal rates of TCE on biochar-iron composites reached above 90%,and the optimal removal conditions were the initial pH of 6.0 and a biochar/iron mass ratio of 5:1.The removal of TCE on biochar-iron composites followed the pseudo-second-order and Freundlich models,and the maximum adsorption capacity of TCE was 25.95 mg/g.The adsorption of biochar and dechlorination of nZVI dominated the removal of TCE.Biochar significantly enhanced the dechlorination of TCE on nZVI through modifying the electrochemical characteristics to lower its corrosion potential of nZVI,promote direct electron transfer,and improve electronic transfer capability.M-5BC-1nZVI exhibited excellent hydraulic performance for maintaining an adequate permeability coefficient(10^(−6)to 10^(−5)m/s).展开更多
Achieving high selectivity to 2,5-furandicarboxylic acid(FDCA)in the photocatalytic oxidation of 5-hydroxymethylfurfural(HMF)in aqueous solution advocates the principle of green and sustainable chemistry,but still rem...Achieving high selectivity to 2,5-furandicarboxylic acid(FDCA)in the photocatalytic oxidation of 5-hydroxymethylfurfural(HMF)in aqueous solution advocates the principle of green and sustainable chemistry,but still remains a significant challenge.Herein,manipulating the reactive oxygen species(ROS)has been realized and dramatically promotes the selective photocatalytic oxidation of HMF in aqueous solution.A high FDCAyield of 98.6% has been achieved after 3 h of visible light irradiation over the as-prepared FeO_(x)-Au/TiO_(2) catalyst,being one of the leading photocatalytic performances.Furthermore,satisfactory FDCA yields of higher than 80%could be realized even in the outdoor environment under natural sunlight irradiation,regardless of sunny or cloudy weather.A combination study including physical characterization,kinetic analysis,radical trapping experiments and density functional theory calculations unveils the rate-determining step(oxidation of hydroxyl group)and respective contributions of the generated ROS(1O_(2) and·O_(2)-)in each step of the entire reaction network.The present work would push ahead the understanding of HMF photocatalytic oxidation and contribute to the rational design of high-performance photocatalysts.展开更多
Bio-carbonation of reactive MgO has been regarded as a promising and eco-friendly method for construction and demolition waste(CDW)cementation in various geotechnical engineering applications.However,the beneficial ef...Bio-carbonation of reactive MgO has been regarded as a promising and eco-friendly method for construction and demolition waste(CDW)cementation in various geotechnical engineering applications.However,the beneficial effect of bio-carbonation of reactive MgO cemented CDW(BCM-samples)can be altered when exposed to wetting-drying cycles induced by extreme climate changes or groundwater fluctuations.To better understand the durability of BCM-samples and their underlying deterioration mechanisms,a series of BCM-samples was prepared to investigate their physical-mechanical performance and microstructure evolution subjected to the wetting-drying cycles.The results indicated that the wetting-drying cycles can deteriorate the BCM-samples,and their physical-mechanical behaviors change quickly at the cycle beginning and then smoothly after 2 cycles.With the increase in cycling,the apparent deterioration with efflorescence and microcrack development can be observed.The mass loss and water absorption rates increased while the dry density,compressional wave velocity,and unconfined compression strength decreased.Urea pre-hydrolysis treatment can significantly improve the durability of BCM-samples,as the more hydrated magnesia carbonates(HMCs)enhance the cementing effects.After 10 cycles,the UCS of pre-hydrolyzed samples decreased 25.4%to 4.45 MPa,while that of ordinary samples decreased 50.7%to 1.20 MPa.The deterioration of BCM-samples caused by wetting-drying cycles can be attributed to two factors.One of the main factors is the structural integrity changes caused by the rapid loss of soluble material at the initial cycling stages.Another factor is the decrease in cementation induced by the loss of brucite and HMCs at the following cycle stages.展开更多
We are sorry for the mistakes of Affiliation,"a State Key Laboratory of Advanced Fiber Materials,Center for Advanced Low-Dimension Materials,Donghua University,Shanghai 201620,China"should be replaced by&quo...We are sorry for the mistakes of Affiliation,"a State Key Laboratory of Advanced Fiber Materials,Center for Advanced Low-Dimension Materials,Donghua University,Shanghai 201620,China"should be replaced by"a State Key Laboratory of Advanced Fiber Materials,Center for Advanced Low-Dimension Materials,College of Materials Science and Engineering,Donghua University,Shanghai 201620,China".We apologized for the inconvenience caused by this error.展开更多
A wind-turbine power system is often challenged by voltage instability,reactive power imbalance,and limited fault ride-through capability under grid disturbances.Doubly Fed Induction Generator based wind farms,owing t...A wind-turbine power system is often challenged by voltage instability,reactive power imbalance,and limited fault ride-through capability under grid disturbances.Doubly Fed Induction Generator based wind farms,owing to their partial coupling with the grid,are particularly vulnerable to voltage dips and excessive reactive power absorption during fault events.This study proposes an adaptive control strategy based on Model Reference Adaptive Control integrated with stator flux-oriented vector control to regulate active and reactive power of a DFIG-based wind farm connected to a standard IEEE 9-bus power system under fault conditions.The proposed control scheme is developed and validated using detailed MATLAB/Simulink modeling under normal operation,symmetrical three-phase fault conditions,and post-fault recovery scenarios.A three-phase-to-ground fault is applied at the wind farm interconnection bus for a duration of 150 ms to evaluate transient performance.Simulation results demonstrate that the adaptive controller ensures fast power tracking,effective reactive power support,and enhanced voltage recovery compared to a conventional proportional–integral controller.Quantitatively,the proposed method improves voltage recovery time by approximately 45%,reduces active power overshoot by 38%,and lowers total harmonic distortion by 52% following fault clearance.Furthermore,the adaptive controller maintains stable operation under variations in wind speed and machine parameters without requiring retuning,highlighting its robustness against system uncertainties.The results confirm that the proposed control strategy significantly enhances fault ride-through capability,power quality,and dynamic stability of grid-interfaced wind farms.These findings demonstrate the practical applicability of adaptive control techniques for improving the reliability and resilience of modern power systems with high wind energy penetration.展开更多
In real industrial microgrids(MGs),the length of the primary delivery feeder to the connection point of the main substation is sometimes long.This reduces the power factor and increases reactive power absorption along...In real industrial microgrids(MGs),the length of the primary delivery feeder to the connection point of the main substation is sometimes long.This reduces the power factor and increases reactive power absorption along the primary delivery feeder from the external network.Besides,the giant induction electro-motors as the working horse of industries requires remarkable amounts of reactive power for electro-mechanical energy conversions.To reduce power losses and operating costs of the MG as well as to improve the voltage quality,this study aims at providing an insightful model for optimal placement and sizing of reactive power compensation capacitors in an industrial MG.In the presented model,the objective function considers voltage profile and network power factor improvement at the MG connection point.Also,it realizes power flow equations within which all operational security constraints are considered.Various reactive power compensation strategies including distributed group compensation,centralized compensation at the main substation,and distributed compensation along the primary delivery feeder are scrutinized.A real industrial MG,say as Urmia Petrochemical plant,is considered in numerical validations.The obtained results in each scenario are discussed in depth.As seen,the best performance is obtained when the optimal location and sizing of capacitors are simultaneously determined at the main buses of the industrial plants,at the main substation of the MG,and alongside the primary delivery feeder.In this way,74.81%improvement in power losses reduction,1.3%lower active power import from the main grid,23.5%improvement in power factor,and 37.5%improvement in network voltage deviation summation are seen in this case compared to the base case.展开更多
An optimized volt-ampere reactive(VAR)control framework is proposed for transmission-level power systems to simultaneously mitigate voltage deviations and active-power losses through coordinated control of large-scale...An optimized volt-ampere reactive(VAR)control framework is proposed for transmission-level power systems to simultaneously mitigate voltage deviations and active-power losses through coordinated control of large-scale wind/solar farms with shunt static var generators(SVGs).The model explicitly represents reactive-power regulation characteristics of doubly-fed wind turbines and PV inverters under real-time meteorological conditions,and quantifies SVG high-speed compensation capability,enabling seamless transition from localized VAR management to a globally coordinated strategy.An enhanced adaptive gain-sharing knowledge optimizer(AGSK-SD)integrates simulated annealing and diversity maintenance to autonomously tune voltage-control actions,renewable source reactive-power set-points,and SVG output.The algorithm adaptively modulates knowledge factors and ratios across search phases,performs SA-based fine-grained local exploitation,and periodically re-injects population diversity to prevent premature convergence.Comprehensive tests on IEEE 9-bus and 39-bus systems demonstrate AGSK-SD’s superiority over NSGA-II and MOPSO in hypervolume(HV),inverse generative distance(IGD),and spread metrics while maintaining acceptable computational burden.The method reduces network losses from 2.7191 to 2.15 MW(20.79%reduction)and from 15.1891 to 11.22 MW(26.16%reduction)in the 9-bus and 39-bus systems respectively.Simultaneously,the cumulative voltage-deviation index decreases from 0.0277 to 3.42×10^(−4) p.u.(98.77%reduction)in the 9-bus system,and from 0.0556 to 0.0107 p.u.(80.76%reduction)in the 39-bus system.These improvements demonstrate significant suppression of line losses and voltage fluctuations.Comparative analysis with traditional heuristic optimization algorithms confirms the superior performance of the proposed approach.展开更多
Astrocytes are the most abundant type of glial cell in the central nervous system.Upon injury and inflammation,astrocytes become reactive and undergo morphological and functional changes.Depending on their phenotypic ...Astrocytes are the most abundant type of glial cell in the central nervous system.Upon injury and inflammation,astrocytes become reactive and undergo morphological and functional changes.Depending on their phenotypic classification as A1 or A2,reactive astrocytes contribute to both neurotoxic and neuroprotective responses,respectively.However,this binary classification does not fully capture the diversity of astrocyte responses observed across different diseases and injuries.Transcriptomic analysis has revealed that reactive astrocytes have a complex landscape of gene expression profiles,which emphasizes the heterogeneous nature of their reactivity.Astrocytes actively participate in regulating central nervous system inflammation by interacting with microglia and other cell types,releasing cytokines,and influencing the immune response.The phosphoinositide 3-kinase(PI3K)/protein kinase B(AKT)signaling pathway is a central player in astrocyte reactivity and impacts various aspects of astrocyte behavior,as evidenced by in silico,in vitro,and in vivo results.In astrocytes,inflammatory cues trigger a cascade of molecular events,where nuclear factor-κB serves as a central mediator of the pro-inflammatory responses.Here,we review the heterogeneity of reactive astrocytes and the molecular mechanisms underlying their activation.We highlight the involvement of various signaling pathways that regulate astrocyte reactivity,including the PI3K/AKT/mammalian target of rapamycin(mTOR),αvβ3 integrin/PI3K/AKT/connexin 43,and Notch/PI3K/AKT pathways.While targeting the inactivation of the PI3K/AKT cellular signaling pathway to control reactive astrocytes and prevent central nervous system damage,evidence suggests that activating this pathway could also yield beneficial outcomes.This dual function of the PI3K/AKT pathway underscores its complexity in astrocyte reactivity and brain function modulation.The review emphasizes the importance of employing astrocyte-exclusive models to understand their functions accurately and these models are essential for clarifying astrocyte behavior.The findings should then be validated using in vivo models to ensure real-life relevance.The review also highlights the significance of PI3K/AKT pathway modulation in preventing central nervous system damage,although further studies are required to fully comprehend its role due to varying factors such as different cell types,astrocyte responses to inflammation,and disease contexts.Specific strategies are clearly necessary to address these variables effectively.展开更多
The penetration-deflagration coupling damage performance of rod-like reactive shaped charge pene-trator(RRSCP)impacting thick steel plates is investigated by theoretical analysis and experiments.A penetration-deflagra...The penetration-deflagration coupling damage performance of rod-like reactive shaped charge pene-trator(RRSCP)impacting thick steel plates is investigated by theoretical analysis and experiments.A penetration-deflagration coupling damage model is developed to predict the penetration depth and cratering diameter.Four type of aluminum-polytetrafluoroethylene-copper(Al-PTFE-Cu)reactive liners with densities of 2.3,2.7,3.5,and 4.5 g·cm^(-3) are selected to conduct the penetration experiments.The comparison results show that model predictions are in good agreement with the experimental data.By comparing the penetration depth and cratering diameter in the inert penetration mode and the penetration-deflagration coupling mode,the influence mechanism that the penetration-induced chemical response is unfavorable to penetration but has an enhanced cratering effect is revealed.From the formation characteristics,penetration effect and penetration-induced chemical reaction be-haviors,the influence of reactive liner density on the penetration-deflagration performance is further analyzed.The results show that increasing the density of reactive liner significantly increases both the kinetic energy and length of the reactive penetrator,meanwhile effectively reduces the weakened effect of penetration-induced chemical response,resulting in an enhanced penetration capability.However,due to the decreased diameter and potential energy content of reactive penetrator,the cratering capa-bility is weakened significantly.展开更多
Particulate matter(PM)can cause adverse health effects by overproducing reactive oxygen species(ROS).Although the ability of PM to induce ROS generation depends on its composi-tion and environmental factors.This study...Particulate matter(PM)can cause adverse health effects by overproducing reactive oxygen species(ROS).Although the ability of PM to induce ROS generation depends on its composi-tion and environmental factors.This study explores how photo-oxidation affects ROS gen-eration from aromatic compounds(ACs,including catechol(CAT),phthalic acid(PA),and 4,4-oxydibenzoic acid(4,4-OBA))and their mixtures with transition metals(TMs,includ-ing Fe(II),Mn(II),and Cu(II))using Fourier-transform infrared(FTIR)and Ultraviolet-visible spectroscopy(UV-Vis).Results showed that photo-oxidation facilitated ROS generation from ACs.CAT-Fe(II)/Cu(II)showed synergistic effects,but 4,4-OBA-Fe(II)/Cu(II)showed antag-onistic effects.ACs-Mn(II)and PA-Fe(II)/Cu(II)exhibited synergistic effects first and then showed antagonistic effects.The different interactions were due to complexation between ACs and TMs.The photo-oxidized ACs-TMs significantly enhanced ROS generation com-pared with ACs-TMs.The study suggested the photo-oxidation mechanism involved that the transfer ofπ-electrons from the ground to an excited state in benzene rings and func-tional groups,leading to the breakage and formation of chemical bonds or easierπ-electron transfer from ACs to TMs.The former could generate ROS directly or produce polymers that promoted ROS generation,while the latter promoted ROS generation by transferringπ-electrons to dissolved oxygen quickly.Our study revealed that both interactions among components and photo-oxidation significantly influenced ROS generation.Future studies should integrate broader atmospheric factors and PM components to fully assess oxidative potential and health impacts.展开更多
Honglian type-cytoplasmic male sterility(HL-CMS)is caused by the inter-communication between the nucleus and mitochondria.However,the mechanisms by which sterility genes regulate metabolic alterations and changes in m...Honglian type-cytoplasmic male sterility(HL-CMS)is caused by the inter-communication between the nucleus and mitochondria.However,the mechanisms by which sterility genes regulate metabolic alterations and changes in mitochondrial morphology in the pollen of HL-CMS remain unclear.In this study,we compared the morphological differences between the pollen of the male sterile line YA and the near-isogenic line NIL-Rf6 using hematoxylin-eosin staining and 4ʹ,6-diamidino-2-phenylindole(DAPI)staining.HL-CMS is characterized by gametophytic sterility,where the aborted pollen grains are empty,and the tapetal layer remains intact.Transmission electron microscopy was employed to observe mitochondrial morphological changes at the microspore stage,revealing significant mitochondrial alterations,characterized by the formation of'large spherical mitochondria',occurred at the binucleate stage in the YA line.Additionally,metabolomics analysis revealed decreased levels of metabolites associated with the carbohydrate and flavonoid pathways.Notably,the decrease in flavonoids was found to contribute to an elevation in reactive oxygen species(ROS)levels.Therefore,we propose a model in which rice fertility is modulated by the levels of pollen carbohydrates and flavonoid metabolites,with impaired mitochondrial energy production and reduced flavonoid biosynthesis as the main causes of ROS accumulation and pollen abortion in rice.展开更多
The phase-locked loop(PLL)plays an essential role for synchronizing renewable power generation to the grid.However,as per the grid-code compliance for reactive current support,the PLL output frequency fluctuates signi...The phase-locked loop(PLL)plays an essential role for synchronizing renewable power generation to the grid.However,as per the grid-code compliance for reactive current support,the PLL output frequency fluctuates significantly and exceeds the limitation,which seriously threaten the safe supply of electricity.In this paper,the underlying theoretical mechanism and dominant force behind the maximum PLL frequency deviation are revealed.Accordingly,two feasible approaches are proposed to enhance the PLL frequency stability with validations in experimental results.展开更多
The presence of heavy metals in soil negatively impacts its mechanical properties.Reactive MgO carbonation presents a promising approach to enhance the solidification of Pb-contaminated sandy soils.However,the mechani...The presence of heavy metals in soil negatively impacts its mechanical properties.Reactive MgO carbonation presents a promising approach to enhance the solidification of Pb-contaminated sandy soils.However,the mechanical properties and structural behavior of contaminated soils during carbonation can vary significantly due to differences in soil composition.This study examines the potential application and underlying mechanisms of reactive MgO carbonation in improving the mechanical properties of Pb-contaminated red clay.The findings demonstrate that Pb-contaminated red clay transitions from a plastic to a brittle state following reactive MgO carbonation.After 1 h of treatment,the strength of the red clay exceeded 3 MPa,even at high Pb^(2+)concentrations.The deformation modulus to unconfined compressive strength(UCS)ratio was calculated to be 37.761,with the failure strain primarily ranging from 1.5%to 4.0%.A strength prediction model for the reactive MgO-stabilized Pb-contaminated red clay was proposed,which showed good predictive accuracy.Furthermore,reactive MgO carbonation significantly reduced the Pb leaching concentration in the high-level Pb-contaminated soil to below 0.1 mg/L.Microscopic analysis revealed that an optimal amount of hydrated magnesium carbonates(HMCs)formed a stable and compact structure with the soil particles.However,long-term carbonation causes red clay particles to become sandy,and excessive HMCs can harm the soil structure.Therefore,to maximize the strength improvement while avoiding structural damage,the carbonation time should be controlled to 1 h.展开更多
Geological CO_(2) storage is a promising strategy for reducing greenhouse gas emissions;however,its underlying multiphase reactive flow mechanisms remain poorly understood.We conducted steady-state imbibition relative...Geological CO_(2) storage is a promising strategy for reducing greenhouse gas emissions;however,its underlying multiphase reactive flow mechanisms remain poorly understood.We conducted steady-state imbibition relative permeability experiments on sandstone from a proposed storage site,comple-mented by in situ X-ray imaging and ex situ analyses using scanning electron microscopy(SEM)and energy-dispersive X-ray spectroscopy(EDS).Despite our use of a brine that was pre-equilibrated with CO_(2),there was a significant reduction in both CO_(2) relative permeability and absolute permeability during multiphase flow due to chemical reactions.This reduction was driven by decreased pore and throat sizes,diminished connectivity,and increased irregularity of pore and throat shapes,as revealed by in situ pore-scale imaging.Mineral dissolution,primarily of feldspar,albite,and calcite,along with precipitation resulting from feldspar-to-kaolinite transformation and fines migration,were identified as contributing factors through SEM-EDS analysis.This work provides a benchmark for storage in mineralogically complex sandstones,for which the impact of chemical reactions on multiphase flow properties has been measured.展开更多
Considering the uncertainty of grid connection of electric vehicle charging stations and the uncertainty of new energy and residential electricity load,a spatio-temporal decoupling strategy of dynamic reactive power o...Considering the uncertainty of grid connection of electric vehicle charging stations and the uncertainty of new energy and residential electricity load,a spatio-temporal decoupling strategy of dynamic reactive power optimization based on clustering-local relaxation-correction is proposed.Firstly,the k-medoids clustering algorithm is used to divide the reduced power scene into periods.Then,the discrete variables and continuous variables are optimized in the same period of time.Finally,the number of input groups of parallel capacitor banks(CB)in multiple periods is fixed,and then the secondary static reactive power optimization correction is carried out by using the continuous reactive power output device based on the static reactive power compensation device(SVC),the new energy grid-connected inverter,and the electric vehicle charging station.According to the characteristics of the model,a hybrid optimization algorithm with a cross-feedback mechanism is used to solve different types of variables,and an improved artificial hummingbird algorithm based on tent chaotic mapping and adaptive mutation is proposed to improve the solution efficiency.The simulation results show that the proposed decoupling strategy can obtain satisfactory optimization resultswhile strictly guaranteeing the dynamic constraints of discrete variables,and the hybrid algorithm can effectively solve the mixed integer nonlinear optimization problem.展开更多
基金the support received from the National Natural Science Foundation of China(Grant No.12302460)the State Key Laboratory of Explosion Science and Safety Protection(Grant No.YBKT24-02)。
文摘The reactive materials filled structure(RMFS)is a structural penetrator that replaces high explosive(HE)with reactive materials,presenting a novel self-distributed initiation,multiple deflagrations behavior during penetrating multi-layered plates,and generating a multipeak overpressure behind the plates.Here analytical models of RMFS self-distributed energy release and equivalent deflagration are developed.The multipeak overpressure formation model based on the single deflagration overpressure expression was promoted.The impact tests of RMFS on multi-layered plates at 584 m/s,616 m/s,and819 m/s were performed to validate the analytical model.Further,the influence of a single overpressure peak and time intervals versus impact velocity is discussed.The analysis results indicate that the deflagration happened within 20.68 mm behind the plate,the initial impact velocity and plate thickness are the crucial factors that dominate the self-distributed multipeak overpressure effect.Three formation patterns of multipeak overpressure are proposed.
基金financially supported by the National Natural Science Foundation of China(No.52573053).
文摘Reactive compatibilization has been widely applied to enhance the compatibility of polymer blends,thereby improving their mechanical properties.However,it generally reduces the chain mobility and regularity,often leading to slower polymer crystallization.Here,we demonstrate that reactive compatibilization in poly(lactic acid)/poly(butylene adipate-co-terephthalate)(PLA/PBAT)blends unexpectedly promotes PLA matrix crystallization during injection molding,in contrast to the retarded kinetics observed in differential scanning calorimetry isothermal crystallization studies.The phase morphology,rheological behavior,and crystalline structure were systematically analyzed to elucidate markedly different crystallization kinetics under static and shear fields.The potential mechanism underlying crystallization enhancement is attributed to PBAT domain refinement and viscosity increase induced by reactive compatibilization,which,under shear flow,create favorable conditions for crystallization by enhancing PBAT fibril nucleation and retarding the relaxation of oriented PLA chains.This study offers new perspectives on the effect of reactive compatibilization on the polymer crystallization behavior.
文摘Hybrid commutation converters(HCCs)utilizing reverse-blocking integrated gate commutation thyristors(IGCTs)have gained significant attention due to their immunity to commutation failure.Leveraging the recovery enhancement characteristics of IGCTs,HCCs demonstrate superior performance at reduced extinction angles,thereby minimizing reactive power consumption.This study presents a comprehensive investigation into reactive power control strategies for HCCs operating at small extinction angles.First,the topological configuration and commutation principle of HCC are elucidated.Subsequently,the mechanism of HCC reactive power control is analyzed,and a reactive power control strategy is proposed by combining the converter transformer taps with extinction angles.Moreover,the relationship between transformer taps and reactive power exchange under different rated extinction angles is calculated,and the theoretically rated extinction angle is proposed.Finally,to validate the proposed control strategy,a four-terminal ultra-high voltage direct current power grid incorporating HCC technology is modeled and sim-ulated using PSCAD/EMTDC.The simulation results demonstrate that the proposed strategy effectively supports AC systems by reducing reactive power absorption in HCCs,while simultaneously exhibiting enhanced reli-ability and economic efficiency.
基金supported by the National Natural Science Foundation of China under Grant 52277184 and Grant 52277183.
文摘The transient synchronization stability of grid-forming converters(GFMCs)is significantly challenged under grid voltage sags.Continuous efforts have been devoted to analyzing the GFMC transient stability,with limited attention paid to the impacts of control loop dynamics.However,the complex control dynamics,especially the interactions between the active/reactive power control loops and the current saturation process(CSP),are crucial for accurately describing the transient behavior and evaluating the stability.Thus,in this study,a new large-signal GFMC model is established,considering the reactive power control(RPC)with different kinds of controllers and the CSP simultaneously.It is revealed that GFMC does not switch to the current-limited mode immediately,and the dynamics of RPC further affect the transient behavior before the current limiting significantly.Hence,the complex control dynamics can alter the mode switching point of current saturation,thereby increasing the risk of loss of synchronization(LOS).Based on the above findings,comprehensive comparisons of typical RPC controllers are presented to facilitate practical engineering applications.A unified stability enhancement method is proposed for solving the problem of LOS.Finally,experiments validate the correctness of the analysis and the effectiveness of the proposed control strategy.
基金financially supported by the National Natural Science Foundation of China(Nos.52373070,52273071 and U25A20255)the Special Support Plan for High-Level Talents in Zhejiang Province(No.2022R51008)the HZNU scientific research and innovation team project(No.TD2025004).
文摘Rubber-toughened thermoplastic materials have become ubiquitous in modern society owing to their lightweight nature and desirable combination of advantageous performances.Despite the ever-increasing demand,the development of polymer alloys that are lightweight,high-strength,and high-toughness remains an ongoing challenge.Inspired by the unique“salami”microstructure from commercial acrylonitrile butadiene styrene copolymer(ABS)and high-impact polystyrene(HIPS),a facile approach was developed to overcome the trade-off between enhancing the toughness and rigidity of fully polymer-based alloys by virtue of elastomeric salami particles.This strategy entails pre-grafting rigid poly(lactic acid)(PLLA)chains with glycidyl methacrylate-grafted octene ethylene copolymer(POE-g-GMA)using complementary reactive groups.It can be envisaged that the PLLA grafts featuring strong incompatibility with polypropylene(PP)remain fixed in elastomer phase upon the subsequent melt compounding,facilitating the in situ formation of“hard core(PLLA)-soft shell(polyolefin elastomer,POE)”particles in polypropylene(PP)matrix.The all-polymer alloys containing elastomeric salami particles demonstrated unprecedented performance combinations,including upper notched impact strengths(56.8 kJ/m2),even higher tensile strength(36.8 MPa),and Young’s modulus(0.93 GPa)than that of the PP matrix.Furthermore,these materials are lightweight without the incorporation of reinforcing nano-fillers,which is competitive with industrial engineering plastics.It is highly anticipated that this universal and highly efficient protocol will be appropriate for arbitrary rubber toughened/reinforced systems,offering a paradigm in the design of advanced all-polymer alloys.
基金supported by the National Key R&D Program of China(No.2023YFC3707900)the National Natural Science Foundation of China(No.51978157).
文摘Biochar and zero-valent iron are promising materials for the removal of trichloroethylene(TCE)from groundwater,but further research is still required on the synergistic mechanism and hydraulic performance in the permeable reactive barriers(PRBs)with biochar-iron composites.In this work,biochar-iron composites were synthesized by two different methods,and subjected to the microscopic analysis,batch experiments and the PRB’s model tests.The results indicated that the removal rates of TCE on biochar-iron composites reached above 90%,and the optimal removal conditions were the initial pH of 6.0 and a biochar/iron mass ratio of 5:1.The removal of TCE on biochar-iron composites followed the pseudo-second-order and Freundlich models,and the maximum adsorption capacity of TCE was 25.95 mg/g.The adsorption of biochar and dechlorination of nZVI dominated the removal of TCE.Biochar significantly enhanced the dechlorination of TCE on nZVI through modifying the electrochemical characteristics to lower its corrosion potential of nZVI,promote direct electron transfer,and improve electronic transfer capability.M-5BC-1nZVI exhibited excellent hydraulic performance for maintaining an adequate permeability coefficient(10^(−6)to 10^(−5)m/s).
基金supported by the National Natural Science Foundation of China(22278021)State Key Laboratory of Chemical Engineering(No.SKL-ChE-23A01).
文摘Achieving high selectivity to 2,5-furandicarboxylic acid(FDCA)in the photocatalytic oxidation of 5-hydroxymethylfurfural(HMF)in aqueous solution advocates the principle of green and sustainable chemistry,but still remains a significant challenge.Herein,manipulating the reactive oxygen species(ROS)has been realized and dramatically promotes the selective photocatalytic oxidation of HMF in aqueous solution.A high FDCAyield of 98.6% has been achieved after 3 h of visible light irradiation over the as-prepared FeO_(x)-Au/TiO_(2) catalyst,being one of the leading photocatalytic performances.Furthermore,satisfactory FDCA yields of higher than 80%could be realized even in the outdoor environment under natural sunlight irradiation,regardless of sunny or cloudy weather.A combination study including physical characterization,kinetic analysis,radical trapping experiments and density functional theory calculations unveils the rate-determining step(oxidation of hydroxyl group)and respective contributions of the generated ROS(1O_(2) and·O_(2)-)in each step of the entire reaction network.The present work would push ahead the understanding of HMF photocatalytic oxidation and contribute to the rational design of high-performance photocatalysts.
基金supported by the National Natural Science Foundation of China(Grant Nos.42525201 and 42230710).
文摘Bio-carbonation of reactive MgO has been regarded as a promising and eco-friendly method for construction and demolition waste(CDW)cementation in various geotechnical engineering applications.However,the beneficial effect of bio-carbonation of reactive MgO cemented CDW(BCM-samples)can be altered when exposed to wetting-drying cycles induced by extreme climate changes or groundwater fluctuations.To better understand the durability of BCM-samples and their underlying deterioration mechanisms,a series of BCM-samples was prepared to investigate their physical-mechanical performance and microstructure evolution subjected to the wetting-drying cycles.The results indicated that the wetting-drying cycles can deteriorate the BCM-samples,and their physical-mechanical behaviors change quickly at the cycle beginning and then smoothly after 2 cycles.With the increase in cycling,the apparent deterioration with efflorescence and microcrack development can be observed.The mass loss and water absorption rates increased while the dry density,compressional wave velocity,and unconfined compression strength decreased.Urea pre-hydrolysis treatment can significantly improve the durability of BCM-samples,as the more hydrated magnesia carbonates(HMCs)enhance the cementing effects.After 10 cycles,the UCS of pre-hydrolyzed samples decreased 25.4%to 4.45 MPa,while that of ordinary samples decreased 50.7%to 1.20 MPa.The deterioration of BCM-samples caused by wetting-drying cycles can be attributed to two factors.One of the main factors is the structural integrity changes caused by the rapid loss of soluble material at the initial cycling stages.Another factor is the decrease in cementation induced by the loss of brucite and HMCs at the following cycle stages.
文摘We are sorry for the mistakes of Affiliation,"a State Key Laboratory of Advanced Fiber Materials,Center for Advanced Low-Dimension Materials,Donghua University,Shanghai 201620,China"should be replaced by"a State Key Laboratory of Advanced Fiber Materials,Center for Advanced Low-Dimension Materials,College of Materials Science and Engineering,Donghua University,Shanghai 201620,China".We apologized for the inconvenience caused by this error.
文摘A wind-turbine power system is often challenged by voltage instability,reactive power imbalance,and limited fault ride-through capability under grid disturbances.Doubly Fed Induction Generator based wind farms,owing to their partial coupling with the grid,are particularly vulnerable to voltage dips and excessive reactive power absorption during fault events.This study proposes an adaptive control strategy based on Model Reference Adaptive Control integrated with stator flux-oriented vector control to regulate active and reactive power of a DFIG-based wind farm connected to a standard IEEE 9-bus power system under fault conditions.The proposed control scheme is developed and validated using detailed MATLAB/Simulink modeling under normal operation,symmetrical three-phase fault conditions,and post-fault recovery scenarios.A three-phase-to-ground fault is applied at the wind farm interconnection bus for a duration of 150 ms to evaluate transient performance.Simulation results demonstrate that the adaptive controller ensures fast power tracking,effective reactive power support,and enhanced voltage recovery compared to a conventional proportional–integral controller.Quantitatively,the proposed method improves voltage recovery time by approximately 45%,reduces active power overshoot by 38%,and lowers total harmonic distortion by 52% following fault clearance.Furthermore,the adaptive controller maintains stable operation under variations in wind speed and machine parameters without requiring retuning,highlighting its robustness against system uncertainties.The results confirm that the proposed control strategy significantly enhances fault ride-through capability,power quality,and dynamic stability of grid-interfaced wind farms.These findings demonstrate the practical applicability of adaptive control techniques for improving the reliability and resilience of modern power systems with high wind energy penetration.
文摘In real industrial microgrids(MGs),the length of the primary delivery feeder to the connection point of the main substation is sometimes long.This reduces the power factor and increases reactive power absorption along the primary delivery feeder from the external network.Besides,the giant induction electro-motors as the working horse of industries requires remarkable amounts of reactive power for electro-mechanical energy conversions.To reduce power losses and operating costs of the MG as well as to improve the voltage quality,this study aims at providing an insightful model for optimal placement and sizing of reactive power compensation capacitors in an industrial MG.In the presented model,the objective function considers voltage profile and network power factor improvement at the MG connection point.Also,it realizes power flow equations within which all operational security constraints are considered.Various reactive power compensation strategies including distributed group compensation,centralized compensation at the main substation,and distributed compensation along the primary delivery feeder are scrutinized.A real industrial MG,say as Urmia Petrochemical plant,is considered in numerical validations.The obtained results in each scenario are discussed in depth.As seen,the best performance is obtained when the optimal location and sizing of capacitors are simultaneously determined at the main buses of the industrial plants,at the main substation of the MG,and alongside the primary delivery feeder.In this way,74.81%improvement in power losses reduction,1.3%lower active power import from the main grid,23.5%improvement in power factor,and 37.5%improvement in network voltage deviation summation are seen in this case compared to the base case.
基金supported by Yunnan Power Grid Co.,Ltd.Science and Technology Project:Research and application of key technologies for graphical-based power grid accident reconstruction and simulation(YNKJXM20240333).
文摘An optimized volt-ampere reactive(VAR)control framework is proposed for transmission-level power systems to simultaneously mitigate voltage deviations and active-power losses through coordinated control of large-scale wind/solar farms with shunt static var generators(SVGs).The model explicitly represents reactive-power regulation characteristics of doubly-fed wind turbines and PV inverters under real-time meteorological conditions,and quantifies SVG high-speed compensation capability,enabling seamless transition from localized VAR management to a globally coordinated strategy.An enhanced adaptive gain-sharing knowledge optimizer(AGSK-SD)integrates simulated annealing and diversity maintenance to autonomously tune voltage-control actions,renewable source reactive-power set-points,and SVG output.The algorithm adaptively modulates knowledge factors and ratios across search phases,performs SA-based fine-grained local exploitation,and periodically re-injects population diversity to prevent premature convergence.Comprehensive tests on IEEE 9-bus and 39-bus systems demonstrate AGSK-SD’s superiority over NSGA-II and MOPSO in hypervolume(HV),inverse generative distance(IGD),and spread metrics while maintaining acceptable computational burden.The method reduces network losses from 2.7191 to 2.15 MW(20.79%reduction)and from 15.1891 to 11.22 MW(26.16%reduction)in the 9-bus and 39-bus systems respectively.Simultaneously,the cumulative voltage-deviation index decreases from 0.0277 to 3.42×10^(−4) p.u.(98.77%reduction)in the 9-bus system,and from 0.0556 to 0.0107 p.u.(80.76%reduction)in the 39-bus system.These improvements demonstrate significant suppression of line losses and voltage fluctuations.Comparative analysis with traditional heuristic optimization algorithms confirms the superior performance of the proposed approach.
基金supported by Fondo Nacional de Desarrollo Científico y Tecnológico(FONDECYT)#1200836,#1210644,and#1240888,and Agencia Nacional de Investigación y Desarrollo(ANID)-FONDAP#15130011(to LL)FONDECYT#3230227(to MFG).
文摘Astrocytes are the most abundant type of glial cell in the central nervous system.Upon injury and inflammation,astrocytes become reactive and undergo morphological and functional changes.Depending on their phenotypic classification as A1 or A2,reactive astrocytes contribute to both neurotoxic and neuroprotective responses,respectively.However,this binary classification does not fully capture the diversity of astrocyte responses observed across different diseases and injuries.Transcriptomic analysis has revealed that reactive astrocytes have a complex landscape of gene expression profiles,which emphasizes the heterogeneous nature of their reactivity.Astrocytes actively participate in regulating central nervous system inflammation by interacting with microglia and other cell types,releasing cytokines,and influencing the immune response.The phosphoinositide 3-kinase(PI3K)/protein kinase B(AKT)signaling pathway is a central player in astrocyte reactivity and impacts various aspects of astrocyte behavior,as evidenced by in silico,in vitro,and in vivo results.In astrocytes,inflammatory cues trigger a cascade of molecular events,where nuclear factor-κB serves as a central mediator of the pro-inflammatory responses.Here,we review the heterogeneity of reactive astrocytes and the molecular mechanisms underlying their activation.We highlight the involvement of various signaling pathways that regulate astrocyte reactivity,including the PI3K/AKT/mammalian target of rapamycin(mTOR),αvβ3 integrin/PI3K/AKT/connexin 43,and Notch/PI3K/AKT pathways.While targeting the inactivation of the PI3K/AKT cellular signaling pathway to control reactive astrocytes and prevent central nervous system damage,evidence suggests that activating this pathway could also yield beneficial outcomes.This dual function of the PI3K/AKT pathway underscores its complexity in astrocyte reactivity and brain function modulation.The review emphasizes the importance of employing astrocyte-exclusive models to understand their functions accurately and these models are essential for clarifying astrocyte behavior.The findings should then be validated using in vivo models to ensure real-life relevance.The review also highlights the significance of PI3K/AKT pathway modulation in preventing central nervous system damage,although further studies are required to fully comprehend its role due to varying factors such as different cell types,astrocyte responses to inflammation,and disease contexts.Specific strategies are clearly necessary to address these variables effectively.
基金supported by the National Natural Science Foundation of China(Grant No.12172052)the Foundation of State Key Laboratory of Explosion Science and Safety Protection(Grant No.QKKT24-02).
文摘The penetration-deflagration coupling damage performance of rod-like reactive shaped charge pene-trator(RRSCP)impacting thick steel plates is investigated by theoretical analysis and experiments.A penetration-deflagration coupling damage model is developed to predict the penetration depth and cratering diameter.Four type of aluminum-polytetrafluoroethylene-copper(Al-PTFE-Cu)reactive liners with densities of 2.3,2.7,3.5,and 4.5 g·cm^(-3) are selected to conduct the penetration experiments.The comparison results show that model predictions are in good agreement with the experimental data.By comparing the penetration depth and cratering diameter in the inert penetration mode and the penetration-deflagration coupling mode,the influence mechanism that the penetration-induced chemical response is unfavorable to penetration but has an enhanced cratering effect is revealed.From the formation characteristics,penetration effect and penetration-induced chemical reaction be-haviors,the influence of reactive liner density on the penetration-deflagration performance is further analyzed.The results show that increasing the density of reactive liner significantly increases both the kinetic energy and length of the reactive penetrator,meanwhile effectively reduces the weakened effect of penetration-induced chemical response,resulting in an enhanced penetration capability.However,due to the decreased diameter and potential energy content of reactive penetrator,the cratering capa-bility is weakened significantly.
基金supported by the Weiqiao-UCAS Special Projects on Low-Carbon Technology Development(No.GYY-DTFZ-2022-007)the Fundamental Research Funds for the Central Universities(No.E0E48927×2)the National Natural Science Foundation of China(No.21677145).
文摘Particulate matter(PM)can cause adverse health effects by overproducing reactive oxygen species(ROS).Although the ability of PM to induce ROS generation depends on its composi-tion and environmental factors.This study explores how photo-oxidation affects ROS gen-eration from aromatic compounds(ACs,including catechol(CAT),phthalic acid(PA),and 4,4-oxydibenzoic acid(4,4-OBA))and their mixtures with transition metals(TMs,includ-ing Fe(II),Mn(II),and Cu(II))using Fourier-transform infrared(FTIR)and Ultraviolet-visible spectroscopy(UV-Vis).Results showed that photo-oxidation facilitated ROS generation from ACs.CAT-Fe(II)/Cu(II)showed synergistic effects,but 4,4-OBA-Fe(II)/Cu(II)showed antag-onistic effects.ACs-Mn(II)and PA-Fe(II)/Cu(II)exhibited synergistic effects first and then showed antagonistic effects.The different interactions were due to complexation between ACs and TMs.The photo-oxidized ACs-TMs significantly enhanced ROS generation com-pared with ACs-TMs.The study suggested the photo-oxidation mechanism involved that the transfer ofπ-electrons from the ground to an excited state in benzene rings and func-tional groups,leading to the breakage and formation of chemical bonds or easierπ-electron transfer from ACs to TMs.The former could generate ROS directly or produce polymers that promoted ROS generation,while the latter promoted ROS generation by transferringπ-electrons to dissolved oxygen quickly.Our study revealed that both interactions among components and photo-oxidation significantly influenced ROS generation.Future studies should integrate broader atmospheric factors and PM components to fully assess oxidative potential and health impacts.
基金supported by the National Natural Science Foundation of China(Grant No.32472185)the Key Research and Development Program of Hubei Province,China(Grant No.2022BFE003)the Hubei Agriculture Science and Technology Innovation Center program,and the National Rice Industry Technology System,China(Grant No.CARS-01-07).
文摘Honglian type-cytoplasmic male sterility(HL-CMS)is caused by the inter-communication between the nucleus and mitochondria.However,the mechanisms by which sterility genes regulate metabolic alterations and changes in mitochondrial morphology in the pollen of HL-CMS remain unclear.In this study,we compared the morphological differences between the pollen of the male sterile line YA and the near-isogenic line NIL-Rf6 using hematoxylin-eosin staining and 4ʹ,6-diamidino-2-phenylindole(DAPI)staining.HL-CMS is characterized by gametophytic sterility,where the aborted pollen grains are empty,and the tapetal layer remains intact.Transmission electron microscopy was employed to observe mitochondrial morphological changes at the microspore stage,revealing significant mitochondrial alterations,characterized by the formation of'large spherical mitochondria',occurred at the binucleate stage in the YA line.Additionally,metabolomics analysis revealed decreased levels of metabolites associated with the carbohydrate and flavonoid pathways.Notably,the decrease in flavonoids was found to contribute to an elevation in reactive oxygen species(ROS)levels.Therefore,we propose a model in which rice fertility is modulated by the levels of pollen carbohydrates and flavonoid metabolites,with impaired mitochondrial energy production and reduced flavonoid biosynthesis as the main causes of ROS accumulation and pollen abortion in rice.
基金supported by the National Natural Science Foundation of China under Grant 52407069the Science and Technology Project of Zhejiang Province under Grant 2024C01254the China Postdoctoral Science Foundation under Grant 2024T170766 and 2024M762824。
文摘The phase-locked loop(PLL)plays an essential role for synchronizing renewable power generation to the grid.However,as per the grid-code compliance for reactive current support,the PLL output frequency fluctuates significantly and exceeds the limitation,which seriously threaten the safe supply of electricity.In this paper,the underlying theoretical mechanism and dominant force behind the maximum PLL frequency deviation are revealed.Accordingly,two feasible approaches are proposed to enhance the PLL frequency stability with validations in experimental results.
基金supported by the National Key Research and Development Program of China(Grant No.2023YFC3707900)the National Natural Science Foundation of China(Grant Nos.42030710 and 42472337).
文摘The presence of heavy metals in soil negatively impacts its mechanical properties.Reactive MgO carbonation presents a promising approach to enhance the solidification of Pb-contaminated sandy soils.However,the mechanical properties and structural behavior of contaminated soils during carbonation can vary significantly due to differences in soil composition.This study examines the potential application and underlying mechanisms of reactive MgO carbonation in improving the mechanical properties of Pb-contaminated red clay.The findings demonstrate that Pb-contaminated red clay transitions from a plastic to a brittle state following reactive MgO carbonation.After 1 h of treatment,the strength of the red clay exceeded 3 MPa,even at high Pb^(2+)concentrations.The deformation modulus to unconfined compressive strength(UCS)ratio was calculated to be 37.761,with the failure strain primarily ranging from 1.5%to 4.0%.A strength prediction model for the reactive MgO-stabilized Pb-contaminated red clay was proposed,which showed good predictive accuracy.Furthermore,reactive MgO carbonation significantly reduced the Pb leaching concentration in the high-level Pb-contaminated soil to below 0.1 mg/L.Microscopic analysis revealed that an optimal amount of hydrated magnesium carbonates(HMCs)formed a stable and compact structure with the soil particles.However,long-term carbonation causes red clay particles to become sandy,and excessive HMCs can harm the soil structure.Therefore,to maximize the strength improvement while avoiding structural damage,the carbonation time should be controlled to 1 h.
文摘Geological CO_(2) storage is a promising strategy for reducing greenhouse gas emissions;however,its underlying multiphase reactive flow mechanisms remain poorly understood.We conducted steady-state imbibition relative permeability experiments on sandstone from a proposed storage site,comple-mented by in situ X-ray imaging and ex situ analyses using scanning electron microscopy(SEM)and energy-dispersive X-ray spectroscopy(EDS).Despite our use of a brine that was pre-equilibrated with CO_(2),there was a significant reduction in both CO_(2) relative permeability and absolute permeability during multiphase flow due to chemical reactions.This reduction was driven by decreased pore and throat sizes,diminished connectivity,and increased irregularity of pore and throat shapes,as revealed by in situ pore-scale imaging.Mineral dissolution,primarily of feldspar,albite,and calcite,along with precipitation resulting from feldspar-to-kaolinite transformation and fines migration,were identified as contributing factors through SEM-EDS analysis.This work provides a benchmark for storage in mineralogically complex sandstones,for which the impact of chemical reactions on multiphase flow properties has been measured.
基金funded by the“Research and Application Project of Collaborative Optimization Control Technology for Distribution Station Area for High Proportion Distributed PV Consumption(4000-202318079A-1-1-ZN)”of the Headquarters of the State Grid Corporation.
文摘Considering the uncertainty of grid connection of electric vehicle charging stations and the uncertainty of new energy and residential electricity load,a spatio-temporal decoupling strategy of dynamic reactive power optimization based on clustering-local relaxation-correction is proposed.Firstly,the k-medoids clustering algorithm is used to divide the reduced power scene into periods.Then,the discrete variables and continuous variables are optimized in the same period of time.Finally,the number of input groups of parallel capacitor banks(CB)in multiple periods is fixed,and then the secondary static reactive power optimization correction is carried out by using the continuous reactive power output device based on the static reactive power compensation device(SVC),the new energy grid-connected inverter,and the electric vehicle charging station.According to the characteristics of the model,a hybrid optimization algorithm with a cross-feedback mechanism is used to solve different types of variables,and an improved artificial hummingbird algorithm based on tent chaotic mapping and adaptive mutation is proposed to improve the solution efficiency.The simulation results show that the proposed decoupling strategy can obtain satisfactory optimization resultswhile strictly guaranteeing the dynamic constraints of discrete variables,and the hybrid algorithm can effectively solve the mixed integer nonlinear optimization problem.
