Kinetic impact is the most practical planetary-defense technique,with momentum-transfer efficiency central to deflection design.We present a Monte Carlo photometric framework that couples ejecta sampling,dynamical evo...Kinetic impact is the most practical planetary-defense technique,with momentum-transfer efficiency central to deflection design.We present a Monte Carlo photometric framework that couples ejecta sampling,dynamical evolution,and image synthesis to compare directly with HST,LICIACube,ground-based and Lucy observations of the DART impact.Decomposing ejecta into(1)a highvelocity(~1600 m/s)plume exhibiting Na/K resonance,(2)a low-velocity(~1 m/s)conical component shaped by binary gravity and solar radiation pressure,and(3)meter-scale boulders,we quantify each component’s mass and momentum.Fitting photometric decay curves and morphological evolution yields size-velocity distributions and,via scaling laws,estimates of Dimorphos’bulk density,cratering parameters,and cohesive strength that agree with dynamical constraints.Photometric ejecta modeling therefore provides a robust route to constrain momentum enhancement and target properties,improving predictive capability for kinetic-deflection missions.展开更多
The increasing production and release of synthetic organic chemicals,including pharmaceuticals,into our envi-ronment has allowed these substances to accumulate in our surface water systems.Current purification technol...The increasing production and release of synthetic organic chemicals,including pharmaceuticals,into our envi-ronment has allowed these substances to accumulate in our surface water systems.Current purification technolo-gies have been unable to eliminate these pollutants,resulting in their ongoing release into aquatic ecosystems.This study focuses on cloperastine(CPS),a cough suppressant and antihistamine medication.The environmental impact of CPS usage has become a concern,mainly due to its increased detection during the COVID-19 pandemic.CPS has been found in wastewater treatment facilities,effluents from senior living residences,river waters,and sewage sludge.However,the photosensitivity of CPS and its photodegradation profile remain largely unknown.This study investigates the photodegradation process of CPS under simulated tertiary treatment conditions using UV photolysis,a method commonly applied in some wastewater treatment plants.Several transformation prod-ucts were identified,evaluating their kinetic profiles using chemometric approaches(i.e.,curve fitting and the hard-soft multivariate curve resolution-alternating least squares(HS-MCR-ALS)algorithm)and calculating the reaction quantum yield.As a result,three different transformation products have been detected and correctly identified.In addition,a comprehensive description of the kinetic pathway involved in the photodegradation process of the CPS drug has been provided,including observed kinetic rate constants.展开更多
Non-layered two-dimensional materials(NL2DMs)have emerged as a promising complement to layered 2D materials,offering unique properties derived from their isotropic bonding and structural diversity.However,their synthe...Non-layered two-dimensional materials(NL2DMs)have emerged as a promising complement to layered 2D materials,offering unique properties derived from their isotropic bonding and structural diversity.However,their synthesis is still facing significant challenges due to the lack of intrinsic anisotropic growth driving force.This review comprehensively outlines strategies for chemical vapor deposition(CVD)-based synthesis of NL2DMs,demonstrating how integrated thermodynamic and kinetic control enables precise thickness and morphology modulation.We also analyze the existing challenges and propose future research directions.This systematic framework paves the way for engineering NL2DMs growth with customized functionalities for next-generation optoelectronics,energy storage,and catalysis.展开更多
The utilization of iron coke provides a green pathway for low-carbon ironmaking.To uncover the influence mechanism of iron ore on the behavior and kinetics of iron coke gasification,the effect of iron ore on the micro...The utilization of iron coke provides a green pathway for low-carbon ironmaking.To uncover the influence mechanism of iron ore on the behavior and kinetics of iron coke gasification,the effect of iron ore on the microstructure of iron coke was investigated.Furthermore,a comparative study of the gasification reactions between iron coke and coke was conducted through non-isothermal thermogravimetric method.The findings indicate that compared to coke,iron coke exhibits an augmentation in micropores and specific surface area,and the micropores further extend and interconnect.This provides more adsorption sites for CO_(2) molecules during the gasification process,resulting in a reduction in the initial gasification temperature of iron coke.Accelerating the heating rate in non-isothermal gasification can enhance the reactivity of iron coke.The metallic iron reduced from iron ore is embedded in the carbon matrix,reducing the orderliness of the carbon structure,which is primarily responsible for the heightened reactivity of the carbon atoms.The kinetic study indicates that the random pore model can effectively represent the gasification process of iron coke due to its rich pore structure.Moreover,as the proportion of iron ore increases,the activation energy for the carbon gasification gradually decreases,from 246.2 kJ/mol for coke to 192.5 kJ/mol for iron coke 15wt%.展开更多
The reaction rate constant is a crucial kinetic parameter that governs the charge and discharge performance of batteries,particularly in high-rate and thick-electrode applications.However,conventional estimation or fi...The reaction rate constant is a crucial kinetic parameter that governs the charge and discharge performance of batteries,particularly in high-rate and thick-electrode applications.However,conventional estimation or fitting methods often overestimate the charge transfer overpotential,leading to substantial errors in reaction rate constant measurements.These inaccuracies hinder the accurate prediction of voltage profiles and overall cell performance.In this study,we propose the characteristic time-decomposed overpotential(CTDO)method,which employs a single-layer particle electrode(SLPE)structure to eliminate interference overpotentials.By leveraging the distribution of relaxation times(DRT),our method effectively isolates the characteristic time of the charge transfer process,enabling a more precise determination of the reaction rate constant.Simulation results indicate that our approach reduces measurement errors to below 2%,closely aligning with theoretical values.Furthermore,experimental validation demonstrates an 80% reduction in error compared to the conventional galvanostatic intermittent titration technique(GITT)method.Overall,this study provides a novel voltage-based approach for determining the reaction rate constant,enhancing the applicability of theoretical analysis in electrode structural design and facilitating rapid battery optimization.展开更多
The characteristics of summertime raindrop size distribution(DSD) and associated relations in the semi-arid region over the Inner Mongolian Plateau(IMP) were investigated,utilizing five-year continuous observations by...The characteristics of summertime raindrop size distribution(DSD) and associated relations in the semi-arid region over the Inner Mongolian Plateau(IMP) were investigated,utilizing five-year continuous observations by a PARSIVEL2disdrometer in East Ujimqin County(EUC),China.It is found that only 7.94% of the 15 664 one-min precipitation samples meet classification criteria as convective rain(CR),but its contribution to the total rainfall amount is 63.87%.Notably,40.72% of the rainfall comes from large-sized raindrops(D> 3 mm),despite the fact that large-sized raindrops account for only 1.73% of the CR total number concentration.Further results show that the mean value of mass-weighted mean diameters(Dm) is larger(2.43 mm) and generalized intercepts(lgN_(W)) is lower(3.19) in CR,aligning with a "continentallike" cluster,which is mainly influenced by the joint impact of in-cloud ice-based processes and the below-cloud environmental background.Also,the empirical relationships of shape-slope(μ-Λ),radar reflectivity-rain rate(Z-R),and rainfall kinetic energy(KE_(time)-Rand KE_(time)-Z) are localized.To quantitatively analyze the impact of DSD parameters on kinetic energy estimation,power-law KE_(time)-R and KE_(time)-Z relationships are derived based on the normalized gamma distribution.N_(W)takes precedence over μ in affecting variabilities of multiplicative coefficients,especially for KE_(time)-R relationship where the multiplicative coefficient is proportional to N_(W)^(-0.287).It should be noted that although the proportion of CR occurring throughout the summer is small,raindrops with lower N_(W) and larger Dmwill generate higher KE_(time),which will bring a higher potential risk of soil erosion in semi-arid regions over IMP.展开更多
The cavity characteristics in liquid-filled containers caused by high-velocity impacts represent an important area of research in hydrodynamic ram phenomena.The dynamic expansion of the cavity induces liquid pressure ...The cavity characteristics in liquid-filled containers caused by high-velocity impacts represent an important area of research in hydrodynamic ram phenomena.The dynamic expansion of the cavity induces liquid pressure variations,potentially causing catastrophic damage to the container.Current studies mainly focus on non-deforming projectiles,such as fragments,with limited exploration of shaped charge jets.In this paper,a uniquely experimental system was designed to record cavity profiles in behind-armor liquid-filled containers subjected to shaped charge jet impacts.The impact process was then numerically reproduced using the explicit simulation program ANSYS LS-DYNA with the Structured Arbitrary Lagrangian-Eulerian(S-ALE)solver.The formation mechanism,along with the dimensional and shape evolution of the cavity was investigated.Additionally,the influence of the impact kinetic energy of the jet on the cavity characteristics was analyzed.The findings reveal that the cavity profile exhibits a conical shape,primarily driven by direct jet impact and inertial effects.The expansion rates of both cavity length and maximum radius increase with jet impact kinetic energy.When the impact kinetic energy is reduced to 28.2 kJ or below,the length-to-diameter ratio of the cavity ultimately stabilizes at approximately 7.展开更多
The accumulation and release of deformation energy within the rock mass of a roadway are primary contributors to the occurrence of rock bursts.This study introduces a calculation model for the kinetic energy generated...The accumulation and release of deformation energy within the rock mass of a roadway are primary contributors to the occurrence of rock bursts.This study introduces a calculation model for the kinetic energy generated during roadway excavation,which is based on the fracture and energy states of the rock mass.The relationships among the mining depth,width of the plastic zone,rebound range of the roof and floor,stress concentration factor,and the induced kinetic energy are systematically explored.Furthermore,a rock burst risk evaluation method is proposed.The findings indicate that the energy evolution of the rock mass can be categorized into four stages:energy accumulation due to in-situ stress,energy accumulation resulting from coal compression,energy dissipation through coal plastic deformation,and energy consumption due to coal failure.The energy release from the rock mass is influenced by several factors,including mining depth,stress concentration factor,the width of the plastic zone,and the rebound range of the roof and floor.Within the plastic zone of coal,the energy released per unit volume of coal and the induced kinetic energy exhibit a nonlinear increase with mining depth and stress concentration factor,while they decrease linearly as the width of the plastic zone increases.Similarly,the driving energy per unit volume of the roof and floor shows a nonlinear increase with mining depth and stress concentration factor,a linear increase with the rebound range of the roof and floor,and a linear decrease with the width of the plastic zone.A rock burst risk evaluation method is developed based on the kinetic energy model.Field observations demonstrate that this method aligns with the drilling cuttings rock burst risk assessment method,thereby confirming its validity.展开更多
Burial dissolution is a critical diagenetic process influencing ultra-deep carbonate reservoir development and preservation.Artificial carbonate samples with different internal structures were prepared,and high-temper...Burial dissolution is a critical diagenetic process influencing ultra-deep carbonate reservoir development and preservation.Artificial carbonate samples with different internal structures were prepared,and high-temperature and highpressure dissolution kinetic simulations were conducted.The results demonstrate that the intensity of burial dissolution is controlled by temperature and pressure,while tectonic-fluid activity influences the development pattern of burial dissolution,ultimately determining the direction of its differential modification.Extensive burial dissolution is likely to occur primarily at relatively shallow depths,significantly influencing reservoir formation,preservation,modification,and adjustment.The development of faults facilitates the maintenance of the intensity of burial dissolution.The maximum intensity of burial dissolution occurs at the tips and overlap zones of faults and intersections of multiple faults.The larger the scale of the faults,the more conducive it is to the development of burial dissolution.Burial dissolution fosters the formation of fault networks characterized by enhanced reservoir capacity and permeability.Burial dissolution controlled by episodic tectonic-fluid activity is a plausible explanation for forming the Tarim Basin's ultra-deep fault-controlled“stringbead-like”reservoirs.展开更多
Electrical energy can be harvested from the rotational kinetic energy of moving bodies,consisting of both mechanical and kinetic energy as a potential power source through electromagnetic induction,similar to wind ene...Electrical energy can be harvested from the rotational kinetic energy of moving bodies,consisting of both mechanical and kinetic energy as a potential power source through electromagnetic induction,similar to wind energy applications.In industries,rotational bodies are commonly present in operations,yet this kinetic energy remains untapped.This research explores the energy generation characteristics of two rotational body types,disk-shaped and cylinder-shaped under specific experimental setups.The hardware setup included a direct current(DC)motor driver,power supply,DC generator,mechanical support,and load resistance,while the software setup involved automation testing tools and data logging.Electromagnetic induction was used to harvest energy,and experiments were conducted at room temperature(25℃)with controlled variables like speed and friction.Results showed the disk-shaped body exhibited higher energy efficiency than the cylinder-shaped body,largely due to lower mechanical losses.The disk required only two bearings,while the cylinder required four,resulting in lower bearing losses for the disk.Additionally,the disk experienced only air friction,whereas the cylinder encountered friction from a soft,uneven rubber material,increasing surface contact losses.Under a 40 W resistive load,the disk demonstrated a 17.1%energy loss due to mechanical friction,achieving up to 15.55 J of recycled energy.Conversely,the cylinder body experienced a 48.05%energy loss,delivering only 51.95%of energy to the load.These insights suggest significant potential for designing efficient energy recycling systems in industrial settings,particularly in manufacturing and processing industries where rotational machinery is prevalent.Despite its lower energy density,this system could be beneficially integrated with energy storage solutions,enhancing sustainability in industrial practices.展开更多
Rechargeable magnesium batteries(RMBs)have been considered a promising“post lithium-ion battery”system to meet the rapidly increasing demand of the emerging electric vehicle and grid energy storage market.However,th...Rechargeable magnesium batteries(RMBs)have been considered a promising“post lithium-ion battery”system to meet the rapidly increasing demand of the emerging electric vehicle and grid energy storage market.However,the sluggish diffusion kinetics of bivalent Mg^(2+)in the host material,related to the strong Coulomb effect between Mg^(2+)and host anion lattices,hinders their further development toward practical applications.Defect engineering,regarded as an effective strategy to break through the slow migration puzzle,has been validated in various cathode materials for RMBs.In this review,we first thoroughly understand the intrinsic mechanism of Mg^(2+)diffusion in cathode materials,from which the key factors affecting ion diffusion are further presented.Then,the positive effects of purposely introduced defects,including vacancy and doping,and the corresponding strategies for introducing various defects are discussed.The applications of defect engineering in cathode materials for RMBs with advanced electrochemical properties are also summarized.Finally,the existing challenges and future perspectives of defect engineering in cathode materials for the overall high-performance RMBs are described.展开更多
Peng et al.in[Phys.Rev.Research,2020,2(3):033089,11 pp.]formulated one-way fluxes for a general chemical reaction far from equilibrium,with arbitrary complex mechanisms,multiple intermediates,and internal kinetic cycl...Peng et al.in[Phys.Rev.Research,2020,2(3):033089,11 pp.]formulated one-way fluxes for a general chemical reaction far from equilibrium,with arbitrary complex mechanisms,multiple intermediates,and internal kinetic cycles.They defined the limit of the ratio of mesoscopic one-way fluxes and the volume of the tank reactor when the volume tends to infinity as macroscopic one-way fluxes,but a rigorous proof of existence of the limit is still awaiting.In this article,we fill this gap under a mild hypothesis:the Markov chain associated with the chemical master equation has finite states and any two columns in the stoichiometric matrices are not identical.In fact,an explicit expression of the limit is obtained.展开更多
Eggshells,a by-product of the food industry,represent a significant yet often overlooked waste stream.Given their vast production volume and inherent properties,eggshells have the potential to serve as a sustainable a...Eggshells,a by-product of the food industry,represent a significant yet often overlooked waste stream.Given their vast production volume and inherent properties,eggshells have the potential to serve as a sustainable and environmentally friendly co-fuel.Aiming to explore the co-combustion characteristics and kinetics of pulverized coal blended with eggshells and offer insights into their combined use as a renewable energy source,a systematic investigation was conducted to evaluate the physical and chemical properties of Shangwan bituminous coal,Shouyang anthracite coal,eggshell(ES)and their blends.Additionally,comprehensive experimental analyses were performed at different heating rates applying a non-isothermal thermogravimetric method.The findings revealed that the addition of ES enhanced the combustion efficiency.The combustion characteristics were significantly influenced by the ES content,with an optimal blend ratio identified for maximum combustion efficiency.To represent the thermal degradation experiments,random pore model and volume model were employed.Furthermore,activation energies and pre-exponential factors were determined.The random pore model demonstrated more superior performance compared to the volume model.The activation energies of all the samples ranged between 18.29 and 42.48 kJ/mol,with the lowest value observed for the sample containing 20 mass%ES.展开更多
The suspension stage of copper flash smelting was examined by roasting a high arsenic copper smelting feed mixture at 500-900°C for 0-20 s in nitrogen and air atmospheres.The enrichment of copper,lead,zinc,arseni...The suspension stage of copper flash smelting was examined by roasting a high arsenic copper smelting feed mixture at 500-900°C for 0-20 s in nitrogen and air atmospheres.The enrichment of copper,lead,zinc,arsenic,and sulfur in the quenched calcine was determined via chemical analyses.Pyrite and chalcopyrite were the main minerals in the feed mixture,and about 55 wt.%of arsenic was in tennantite.The stability of the feed and the formation of S_(2) and SO_(2)during roasting were surveyed by thermal analysis combined with mass spectrometry.Selected pure impurity sulfides were studied for reference purposes.Results indicated that arsenic was released more easily in inert atmosphere compared to air,in which oxidation products of sulfides captured the released gaseous arsenic.Kinetics analyses showed that the third-order chemical reaction and three-dimensional diffusion models were found as the most suitable mechanism functions of arsenic volatilization in inert and air atmospheres,respectively.展开更多
Superconducting kinetic inductance detectors(KIDs)are considered to be a highly promising technique for the large-scale imaging of millimeter and submillimeter waves in astronomy.As the pixel density and the array siz...Superconducting kinetic inductance detectors(KIDs)are considered to be a highly promising technique for the large-scale imaging of millimeter and submillimeter waves in astronomy.As the pixel density and the array size increase,the electromagnetic crosstalk inevitably becomes a problem that prevents increasing the multiplexing during the development of larger KIDs arrays.In this work,an effective method is introduced to suppress the electromagnetic crosstalk and achieve a compact pixel distribution and small frequency intervals.The electromagnetic crosstalk is first analyzed by simulating the behavior of two neighboring pixels,and the physical distance and the frequency interval are optimized.Then,the arrangement of the pixels on the whole array is redesigned using a genetic algorithm to satisfy the requirements.The simulation results reveal that the normalized electromagnetic crosstalk can be reduced to 0.5%on an 8×8 array.Larger arrays of 16×16 pixels have been fabricated and measured to validate this method,and the results reveal that both the resonance property and survival rate of pixels are improved effectively with this method.This method will be very helpful for designing high-multiplexing KIDs arrays within a limited bandwidth.展开更多
Interaction of dynamic magnetic island with bootstrap current in toroidal plasmas is investigated based on the first principles of kinetic simulation.The perturbed magnetic and electric fields associated with the dyna...Interaction of dynamic magnetic island with bootstrap current in toroidal plasmas is investigated based on the first principles of kinetic simulation.The perturbed magnetic and electric fields associated with the dynamic magnetic island are calculated from a three-dimensional toroidal MHD code(CLT),instead of artificial imposed magnetic island perturbation.Inside the static magnetic island,the bootstrap current decreases as expected with the effective collision frequency.The radial electric field Erassociated with dynamic island could cause the E×B drift,which can noticeably modify the bootstrap current distribution.If the bootstrap current turns on when the tearing mode saturates,the widths of magnetic islands ascend rapidly and saturate again for both static and dynamic cases.But the saturated island width of the dynamic case is smaller than that of the static case because the magnetic islands in the dynamic case rotate due to strong asymmetric distribution of the bootstrap current in the vicinity of the X-points.展开更多
Methyl methoxyacetate(MMAc)and methyl formate(MF)can be produced directly by heterogeneous zeolite-catalyzed carbonylation and disproportionation of dimethoxymethane(DMM),with near 100%selectivity for each process.Des...Methyl methoxyacetate(MMAc)and methyl formate(MF)can be produced directly by heterogeneous zeolite-catalyzed carbonylation and disproportionation of dimethoxymethane(DMM),with near 100%selectivity for each process.Despite continuous research efforts,the insight into the reaction mechanism and kinetics theory are still in their nascent stage.In this study,ZEO-1 material,a zeolite with up to now the largest cages comprising 16×16-MRs,16×12-MRs,and 12×12-MRs,was explored for DMM carbonylation and disproportionation reactions.The rate of MMAc formation based on accessible Brönsted acid sites is 2.5 times higher for ZEO-1(Si/Al=21)relative to the previously investigated FAU(Si/Al=15),indicating the positive effect of spatial separation of active sites in ZEO-1 on catalytic activity.A higher MF formation rate is also observed over ZEO-1 with lower activation energy(79.94 vs.95.19 kJ/mol)compared with FAU(Si/Al=30).Two types of active sites are proposed within ZEO-1 zeolite:Site 1 located in large cages formed by 16×16-MRs and 16×12-MRs,which is active predominantly for MMAc formation,and Site 2 located in smaller cages for methyl formate/dimethyl ether formation.Kinetics investigation of DMM carbonylation over ZEO-1 exhibit a first-order dependence on CO partial pressure and a slightly inverse-order dependence on DMM partial pressure.The DMM disproportionation is nearly first-order dependence on DMM partial pressure,while it reveals a strongly inverse dependence with increasing CO partial pressure.Furthermore,ZEO-1 exhibits good catalytic stability,and almost no deactivation is observed during the more than 70 h test with high carbonylation selectivity of above 89%,due to the well-enhanced diffusion property demonstrated by intelligent-gravimetric analysis.展开更多
Phosphoric acid is a key ingredient in fertilizer production and contains many rare earth elements(REEs).Recovering REEs from phosphoric acid can prevent the accumulation of these elements in the soil and help bridge ...Phosphoric acid is a key ingredient in fertilizer production and contains many rare earth elements(REEs).Recovering REEs from phosphoric acid can prevent the accumulation of these elements in the soil and help bridge the gap between supply and demand.In this concern,a new material called Si-6G PAMAMPPAAM dendrimers modified silica gel terminated with phenylphosphonic acid-amide moieties was developed and its ability to adsorb Nd(Ⅲ)and Er(Ⅲ)from the phosphoric acid solution was investigated.K inetics and isotherm of the uptake process were investigated to explo re the so rption characte ristics.The attained results show that both metal ions exhibit the same adsorption performance,and the uptake process is depicted as a chemisorption,monolayer,uniform,and homogeneous process.The equilibrium state is achieved within 120 min,and the maximum uptake capacity is 16.7 mg Nd(Ⅲ)/g,and 14.0 mg Er(Ⅲ)/g.Sorption thermodynamics is an endothermic,spontaneous,and feasible uptake process.Nitric acid(1.0 mol/L)is found to be efficient for adsorbing about 94.3%and 92.5%of neodymium(Ⅲ)and erbium(Ⅲ)respectively,and the prepared Si-6G PAMAM-PPAAM demonstrates excellent stability over five consecutive sorption/desorption cycles.Preliminary tests on commercial phosphoric acid demonstrate that Si-6G PAMAM-PPAAM retains its effective REEs uptake from a complex comm ercial phosph oric acid solution.展开更多
To accurately analyze proppant transport in rough intersecting fractures and elucidate the interaction mechanisms among liquid,particles,and rough walls,this study reconstructed a numerical model of fractures in inhom...To accurately analyze proppant transport in rough intersecting fractures and elucidate the interaction mechanisms among liquid,particles,and rough walls,this study reconstructed a numerical model of fractures in inhomogeneous reservoirs with varying brittleness index(BI).Various auto-correlation Gaussian rough fracture models were created using Matlab to assess roughness through the fractal dimension method.This research innovatively combined Boolean operations to establish three-dimensional rough fracture models,incorporating(Computational Fluid Dynamics)CFD-DEM(Discrete Element Method)with a bidirectional method for cosimulation.The proppant transport in fractures was categorized into three zones based on the difference in the turbulent kinetic energy.Artificially induced fracture roughness increases fluid retention and turbulence,causing plugging effects and limiting proppant flow into branch fractures.Additionally,compared with the superior deposition and significant support effects of the spherical proppant,the low-sphericity proppant traveled farther under fracturing fluid,inducing more pronounced plugging near curved fracture intersections;the variation in fracture intersection angles primarily impacted the wall shear stress within the flow field,indicating smaller angles led to higher shear energy at the intersection.Compared with the intersection angle of 30°,the height and area deposited in the 90 branch fracture increased by 52.25%and 65.33%,respectively:notably,injecting proppant from smaller to larger particles(S:M:L)and a low velocity effectively ensured fracture conductivity near the wellbore at joint roughness coefficient(JRC)≥46 while achieving satis-factory placement in the branch fracture,making it a recommended approach.展开更多
Electrocatalysis has been investigated as a promising strategy to utilize green electricity to produce renewable fuels,valuable chemicals,and treat pollutants.Electrode kinetic analysis is a potent technique in interr...Electrocatalysis has been investigated as a promising strategy to utilize green electricity to produce renewable fuels,valuable chemicals,and treat pollutants.Electrode kinetic analysis is a potent technique in interrogating reaction mechanisms and evaluating the electrocatalysts.Electron transfer(ET)and proton‐coupled electron transfer(PCET)processes are widely present in reaction networks of electrocatalysis.pH dependence of the kinetics is frequently employed to evaluate whether an elementary step involves proton participation,which is determined by both the reversibility and the specific reactants of electrode reactions.In this article,we discuss the pH dependence of two widely used formulations of the Butler–Volmer kinetics for a model PCET step and highlight a potential pitfall in kinetic analysis.This work aims to provide guiding principles for distinguishing ET and PCET steps via kinetic measurements in electrolytes in a broad range pH values.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.12272018)the National Key Basic Research Project(2022JCJQZD20600).
文摘Kinetic impact is the most practical planetary-defense technique,with momentum-transfer efficiency central to deflection design.We present a Monte Carlo photometric framework that couples ejecta sampling,dynamical evolution,and image synthesis to compare directly with HST,LICIACube,ground-based and Lucy observations of the DART impact.Decomposing ejecta into(1)a highvelocity(~1600 m/s)plume exhibiting Na/K resonance,(2)a low-velocity(~1 m/s)conical component shaped by binary gravity and solar radiation pressure,and(3)meter-scale boulders,we quantify each component’s mass and momentum.Fitting photometric decay curves and morphological evolution yields size-velocity distributions and,via scaling laws,estimates of Dimorphos’bulk density,cratering parameters,and cohesive strength that agree with dynamical constraints.Photometric ejecta modeling therefore provides a robust route to constrain momentum enhancement and target properties,improving predictive capability for kinetic-deflection missions.
基金supported by the grants PID2020-113371RA-C22 and TED2021-130845A-C32,funded by MCIN/AEI/10.13039/501100011033.M.Marín-García,R.González-OlmosC.Gómez-Canela are members of the GESPA group(Grup d’Enginyeria i Simulacióde Processos Ambientals)at IQS-URL,which has been acknowledged as a Consolidated Research Group by the Government of Catalonia(No.2021-SGR-00321)+1 种基金In addition,M.Marín-García has been awarded a public grant for the Investigo Programme,aimed at hiring young job seekers to undertake research and innovation projects under the Recovery,Transformation,and Resilience Plan(PRTR),European Union Next Generation,for the year 2022,through the Government of Catalonia and the Spanish Ministry for Work and Social Economy(No.100045ID16)Ana Belén Cuenca for her support and expertise,which helped to confirm the proposed reaction mechanism involved in the UV photolysis of cloperastine.
文摘The increasing production and release of synthetic organic chemicals,including pharmaceuticals,into our envi-ronment has allowed these substances to accumulate in our surface water systems.Current purification technolo-gies have been unable to eliminate these pollutants,resulting in their ongoing release into aquatic ecosystems.This study focuses on cloperastine(CPS),a cough suppressant and antihistamine medication.The environmental impact of CPS usage has become a concern,mainly due to its increased detection during the COVID-19 pandemic.CPS has been found in wastewater treatment facilities,effluents from senior living residences,river waters,and sewage sludge.However,the photosensitivity of CPS and its photodegradation profile remain largely unknown.This study investigates the photodegradation process of CPS under simulated tertiary treatment conditions using UV photolysis,a method commonly applied in some wastewater treatment plants.Several transformation prod-ucts were identified,evaluating their kinetic profiles using chemometric approaches(i.e.,curve fitting and the hard-soft multivariate curve resolution-alternating least squares(HS-MCR-ALS)algorithm)and calculating the reaction quantum yield.As a result,three different transformation products have been detected and correctly identified.In addition,a comprehensive description of the kinetic pathway involved in the photodegradation process of the CPS drug has been provided,including observed kinetic rate constants.
基金supported by the National Natural Science Foundation of China(Nos.12474163,52202161 and 12034002)State Key Laboratory for Advanced Metals and Materials(No.2025-S02).
文摘Non-layered two-dimensional materials(NL2DMs)have emerged as a promising complement to layered 2D materials,offering unique properties derived from their isotropic bonding and structural diversity.However,their synthesis is still facing significant challenges due to the lack of intrinsic anisotropic growth driving force.This review comprehensively outlines strategies for chemical vapor deposition(CVD)-based synthesis of NL2DMs,demonstrating how integrated thermodynamic and kinetic control enables precise thickness and morphology modulation.We also analyze the existing challenges and propose future research directions.This systematic framework paves the way for engineering NL2DMs growth with customized functionalities for next-generation optoelectronics,energy storage,and catalysis.
基金financially supported by the National Science Foundation of China(Nos.51974212 and 52274316)the China Baowu Low Carbon Metallurgy Innovation Foundation(No.BWLCF202116)+1 种基金the Science and Technology Major Project of Wuhan(No.2023020302020572)the Foundation of Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education(No.FMRUlab23-04)。
文摘The utilization of iron coke provides a green pathway for low-carbon ironmaking.To uncover the influence mechanism of iron ore on the behavior and kinetics of iron coke gasification,the effect of iron ore on the microstructure of iron coke was investigated.Furthermore,a comparative study of the gasification reactions between iron coke and coke was conducted through non-isothermal thermogravimetric method.The findings indicate that compared to coke,iron coke exhibits an augmentation in micropores and specific surface area,and the micropores further extend and interconnect.This provides more adsorption sites for CO_(2) molecules during the gasification process,resulting in a reduction in the initial gasification temperature of iron coke.Accelerating the heating rate in non-isothermal gasification can enhance the reactivity of iron coke.The metallic iron reduced from iron ore is embedded in the carbon matrix,reducing the orderliness of the carbon structure,which is primarily responsible for the heightened reactivity of the carbon atoms.The kinetic study indicates that the random pore model can effectively represent the gasification process of iron coke due to its rich pore structure.Moreover,as the proportion of iron ore increases,the activation energy for the carbon gasification gradually decreases,from 246.2 kJ/mol for coke to 192.5 kJ/mol for iron coke 15wt%.
基金supported by the National Key R&D Program of China 2022YFB2404300the National Natural Science Foundation of China U22B2069the China Postdoctoral Science Foundation 2024M761006。
文摘The reaction rate constant is a crucial kinetic parameter that governs the charge and discharge performance of batteries,particularly in high-rate and thick-electrode applications.However,conventional estimation or fitting methods often overestimate the charge transfer overpotential,leading to substantial errors in reaction rate constant measurements.These inaccuracies hinder the accurate prediction of voltage profiles and overall cell performance.In this study,we propose the characteristic time-decomposed overpotential(CTDO)method,which employs a single-layer particle electrode(SLPE)structure to eliminate interference overpotentials.By leveraging the distribution of relaxation times(DRT),our method effectively isolates the characteristic time of the charge transfer process,enabling a more precise determination of the reaction rate constant.Simulation results indicate that our approach reduces measurement errors to below 2%,closely aligning with theoretical values.Furthermore,experimental validation demonstrates an 80% reduction in error compared to the conventional galvanostatic intermittent titration technique(GITT)method.Overall,this study provides a novel voltage-based approach for determining the reaction rate constant,enhancing the applicability of theoretical analysis in electrode structural design and facilitating rapid battery optimization.
基金supported by the National Natural Science Foundation of China(Grant Nos.42325503,42075063,42075066,and 42021004)the Hubei Provincial Natural Science Foundation and the Meteorological Innovation and Development Project of China(Grant No.2023AFD096)the Beijige Foundation of NJIAS(Grant No.BJG202304).
文摘The characteristics of summertime raindrop size distribution(DSD) and associated relations in the semi-arid region over the Inner Mongolian Plateau(IMP) were investigated,utilizing five-year continuous observations by a PARSIVEL2disdrometer in East Ujimqin County(EUC),China.It is found that only 7.94% of the 15 664 one-min precipitation samples meet classification criteria as convective rain(CR),but its contribution to the total rainfall amount is 63.87%.Notably,40.72% of the rainfall comes from large-sized raindrops(D> 3 mm),despite the fact that large-sized raindrops account for only 1.73% of the CR total number concentration.Further results show that the mean value of mass-weighted mean diameters(Dm) is larger(2.43 mm) and generalized intercepts(lgN_(W)) is lower(3.19) in CR,aligning with a "continentallike" cluster,which is mainly influenced by the joint impact of in-cloud ice-based processes and the below-cloud environmental background.Also,the empirical relationships of shape-slope(μ-Λ),radar reflectivity-rain rate(Z-R),and rainfall kinetic energy(KE_(time)-Rand KE_(time)-Z) are localized.To quantitatively analyze the impact of DSD parameters on kinetic energy estimation,power-law KE_(time)-R and KE_(time)-Z relationships are derived based on the normalized gamma distribution.N_(W)takes precedence over μ in affecting variabilities of multiplicative coefficients,especially for KE_(time)-R relationship where the multiplicative coefficient is proportional to N_(W)^(-0.287).It should be noted that although the proportion of CR occurring throughout the summer is small,raindrops with lower N_(W) and larger Dmwill generate higher KE_(time),which will bring a higher potential risk of soil erosion in semi-arid regions over IMP.
基金financial support from the National Natural Science Foundation of China(Grant No.11572159).
文摘The cavity characteristics in liquid-filled containers caused by high-velocity impacts represent an important area of research in hydrodynamic ram phenomena.The dynamic expansion of the cavity induces liquid pressure variations,potentially causing catastrophic damage to the container.Current studies mainly focus on non-deforming projectiles,such as fragments,with limited exploration of shaped charge jets.In this paper,a uniquely experimental system was designed to record cavity profiles in behind-armor liquid-filled containers subjected to shaped charge jet impacts.The impact process was then numerically reproduced using the explicit simulation program ANSYS LS-DYNA with the Structured Arbitrary Lagrangian-Eulerian(S-ALE)solver.The formation mechanism,along with the dimensional and shape evolution of the cavity was investigated.Additionally,the influence of the impact kinetic energy of the jet on the cavity characteristics was analyzed.The findings reveal that the cavity profile exhibits a conical shape,primarily driven by direct jet impact and inertial effects.The expansion rates of both cavity length and maximum radius increase with jet impact kinetic energy.When the impact kinetic energy is reduced to 28.2 kJ or below,the length-to-diameter ratio of the cavity ultimately stabilizes at approximately 7.
基金financially supported by the National Natural Science Foundation of China(Nos.52374094 and 52274086)the Climbling Project of Taishan Scholar in Shandong Province(No.tspd20210313)the Shandong Provincial Youth Innovation and Technology Support Program(No.2024KJH069)。
文摘The accumulation and release of deformation energy within the rock mass of a roadway are primary contributors to the occurrence of rock bursts.This study introduces a calculation model for the kinetic energy generated during roadway excavation,which is based on the fracture and energy states of the rock mass.The relationships among the mining depth,width of the plastic zone,rebound range of the roof and floor,stress concentration factor,and the induced kinetic energy are systematically explored.Furthermore,a rock burst risk evaluation method is proposed.The findings indicate that the energy evolution of the rock mass can be categorized into four stages:energy accumulation due to in-situ stress,energy accumulation resulting from coal compression,energy dissipation through coal plastic deformation,and energy consumption due to coal failure.The energy release from the rock mass is influenced by several factors,including mining depth,stress concentration factor,the width of the plastic zone,and the rebound range of the roof and floor.Within the plastic zone of coal,the energy released per unit volume of coal and the induced kinetic energy exhibit a nonlinear increase with mining depth and stress concentration factor,while they decrease linearly as the width of the plastic zone increases.Similarly,the driving energy per unit volume of the roof and floor shows a nonlinear increase with mining depth and stress concentration factor,a linear increase with the rebound range of the roof and floor,and a linear decrease with the width of the plastic zone.A rock burst risk evaluation method is developed based on the kinetic energy model.Field observations demonstrate that this method aligns with the drilling cuttings rock burst risk assessment method,thereby confirming its validity.
基金supported by the National Natural Science Foundation of China(Grant No.U21B2062)supported by the Key Laboratory for Carbonate Reservoirs of China National Petroleum Corporation。
文摘Burial dissolution is a critical diagenetic process influencing ultra-deep carbonate reservoir development and preservation.Artificial carbonate samples with different internal structures were prepared,and high-temperature and highpressure dissolution kinetic simulations were conducted.The results demonstrate that the intensity of burial dissolution is controlled by temperature and pressure,while tectonic-fluid activity influences the development pattern of burial dissolution,ultimately determining the direction of its differential modification.Extensive burial dissolution is likely to occur primarily at relatively shallow depths,significantly influencing reservoir formation,preservation,modification,and adjustment.The development of faults facilitates the maintenance of the intensity of burial dissolution.The maximum intensity of burial dissolution occurs at the tips and overlap zones of faults and intersections of multiple faults.The larger the scale of the faults,the more conducive it is to the development of burial dissolution.Burial dissolution fosters the formation of fault networks characterized by enhanced reservoir capacity and permeability.Burial dissolution controlled by episodic tectonic-fluid activity is a plausible explanation for forming the Tarim Basin's ultra-deep fault-controlled“stringbead-like”reservoirs.
基金The APC was funded by Research Management Center, Multimedia University, Malaysia.
文摘Electrical energy can be harvested from the rotational kinetic energy of moving bodies,consisting of both mechanical and kinetic energy as a potential power source through electromagnetic induction,similar to wind energy applications.In industries,rotational bodies are commonly present in operations,yet this kinetic energy remains untapped.This research explores the energy generation characteristics of two rotational body types,disk-shaped and cylinder-shaped under specific experimental setups.The hardware setup included a direct current(DC)motor driver,power supply,DC generator,mechanical support,and load resistance,while the software setup involved automation testing tools and data logging.Electromagnetic induction was used to harvest energy,and experiments were conducted at room temperature(25℃)with controlled variables like speed and friction.Results showed the disk-shaped body exhibited higher energy efficiency than the cylinder-shaped body,largely due to lower mechanical losses.The disk required only two bearings,while the cylinder required four,resulting in lower bearing losses for the disk.Additionally,the disk experienced only air friction,whereas the cylinder encountered friction from a soft,uneven rubber material,increasing surface contact losses.Under a 40 W resistive load,the disk demonstrated a 17.1%energy loss due to mechanical friction,achieving up to 15.55 J of recycled energy.Conversely,the cylinder body experienced a 48.05%energy loss,delivering only 51.95%of energy to the load.These insights suggest significant potential for designing efficient energy recycling systems in industrial settings,particularly in manufacturing and processing industries where rotational machinery is prevalent.Despite its lower energy density,this system could be beneficially integrated with energy storage solutions,enhancing sustainability in industrial practices.
基金support of the National Natural Science Foundation of China(Grant No.22225801,22178217 and 22308216)supported by the Fundamental Research Funds for the Central Universities,conducted at Tongji University.
文摘Rechargeable magnesium batteries(RMBs)have been considered a promising“post lithium-ion battery”system to meet the rapidly increasing demand of the emerging electric vehicle and grid energy storage market.However,the sluggish diffusion kinetics of bivalent Mg^(2+)in the host material,related to the strong Coulomb effect between Mg^(2+)and host anion lattices,hinders their further development toward practical applications.Defect engineering,regarded as an effective strategy to break through the slow migration puzzle,has been validated in various cathode materials for RMBs.In this review,we first thoroughly understand the intrinsic mechanism of Mg^(2+)diffusion in cathode materials,from which the key factors affecting ion diffusion are further presented.Then,the positive effects of purposely introduced defects,including vacancy and doping,and the corresponding strategies for introducing various defects are discussed.The applications of defect engineering in cathode materials for RMBs with advanced electrochemical properties are also summarized.Finally,the existing challenges and future perspectives of defect engineering in cathode materials for the overall high-performance RMBs are described.
基金partially supported by NSFC(Nos.11701265,11961033).
文摘Peng et al.in[Phys.Rev.Research,2020,2(3):033089,11 pp.]formulated one-way fluxes for a general chemical reaction far from equilibrium,with arbitrary complex mechanisms,multiple intermediates,and internal kinetic cycles.They defined the limit of the ratio of mesoscopic one-way fluxes and the volume of the tank reactor when the volume tends to infinity as macroscopic one-way fluxes,but a rigorous proof of existence of the limit is still awaiting.In this article,we fill this gap under a mild hypothesis:the Markov chain associated with the chemical master equation has finite states and any two columns in the stoichiometric matrices are not identical.In fact,an explicit expression of the limit is obtained.
基金sponsored by the Major Science and Technology Special Plan“Unveiling and Leading”Project of Shanxi Province(No.202201050201011)Major Science and Technology Projects of Anhui Province(No.202210700037)Special Funding for Science and Technology of China Minmetals Corporation(No.2021ZXD01).
文摘Eggshells,a by-product of the food industry,represent a significant yet often overlooked waste stream.Given their vast production volume and inherent properties,eggshells have the potential to serve as a sustainable and environmentally friendly co-fuel.Aiming to explore the co-combustion characteristics and kinetics of pulverized coal blended with eggshells and offer insights into their combined use as a renewable energy source,a systematic investigation was conducted to evaluate the physical and chemical properties of Shangwan bituminous coal,Shouyang anthracite coal,eggshell(ES)and their blends.Additionally,comprehensive experimental analyses were performed at different heating rates applying a non-isothermal thermogravimetric method.The findings revealed that the addition of ES enhanced the combustion efficiency.The combustion characteristics were significantly influenced by the ES content,with an optimal blend ratio identified for maximum combustion efficiency.To represent the thermal degradation experiments,random pore model and volume model were employed.Furthermore,activation energies and pre-exponential factors were determined.The random pore model demonstrated more superior performance compared to the volume model.The activation energies of all the samples ranged between 18.29 and 42.48 kJ/mol,with the lowest value observed for the sample containing 20 mass%ES.
基金support from the Research Foundation for Doctor of Nanyang Institute of Technology,China(No.NGBJ-2022-27)the National Key Research and Development Program of China(No.2023YFC3904002)+3 种基金the National Natural Science Foundation of China(Nos.52064038,52364056)the Science and Technology Research Project of Henan Province,China(No.252102320113)the Key Scientific Research Project Plan of Colleges and Universities in Henan Province,China(No.25B610009)Jiangxi Provincial Natural Science Foundation,China(Nos.20232BCJ22049,20232ACB214009).
文摘The suspension stage of copper flash smelting was examined by roasting a high arsenic copper smelting feed mixture at 500-900°C for 0-20 s in nitrogen and air atmospheres.The enrichment of copper,lead,zinc,arsenic,and sulfur in the quenched calcine was determined via chemical analyses.Pyrite and chalcopyrite were the main minerals in the feed mixture,and about 55 wt.%of arsenic was in tennantite.The stability of the feed and the formation of S_(2) and SO_(2)during roasting were surveyed by thermal analysis combined with mass spectrometry.Selected pure impurity sulfides were studied for reference purposes.Results indicated that arsenic was released more easily in inert atmosphere compared to air,in which oxidation products of sulfides captured the released gaseous arsenic.Kinetics analyses showed that the third-order chemical reaction and three-dimensional diffusion models were found as the most suitable mechanism functions of arsenic volatilization in inert and air atmospheres,respectively.
基金supported by the National Key Research and Development Program of China(2023YFC2206601)the National Natural Science Foundation of China(12273024,62205211)the Science and Technology Commission of Shanghai Municipality(23010503900,22590780100).
文摘Superconducting kinetic inductance detectors(KIDs)are considered to be a highly promising technique for the large-scale imaging of millimeter and submillimeter waves in astronomy.As the pixel density and the array size increase,the electromagnetic crosstalk inevitably becomes a problem that prevents increasing the multiplexing during the development of larger KIDs arrays.In this work,an effective method is introduced to suppress the electromagnetic crosstalk and achieve a compact pixel distribution and small frequency intervals.The electromagnetic crosstalk is first analyzed by simulating the behavior of two neighboring pixels,and the physical distance and the frequency interval are optimized.Then,the arrangement of the pixels on the whole array is redesigned using a genetic algorithm to satisfy the requirements.The simulation results reveal that the normalized electromagnetic crosstalk can be reduced to 0.5%on an 8×8 array.Larger arrays of 16×16 pixels have been fabricated and measured to validate this method,and the results reveal that both the resonance property and survival rate of pixels are improved effectively with this method.This method will be very helpful for designing high-multiplexing KIDs arrays within a limited bandwidth.
基金supported by the National Key Research and Development Program of China(Nos.2022YFE03100000,2019YFE03020003 and 2019YFE03030004)National Natural Science Foundation of China(Nos.11835010,12305236 and 12375224)Innovation Program of Southwestern Institute of Physics(No.202301XWCX001)。
文摘Interaction of dynamic magnetic island with bootstrap current in toroidal plasmas is investigated based on the first principles of kinetic simulation.The perturbed magnetic and electric fields associated with the dynamic magnetic island are calculated from a three-dimensional toroidal MHD code(CLT),instead of artificial imposed magnetic island perturbation.Inside the static magnetic island,the bootstrap current decreases as expected with the effective collision frequency.The radial electric field Erassociated with dynamic island could cause the E×B drift,which can noticeably modify the bootstrap current distribution.If the bootstrap current turns on when the tearing mode saturates,the widths of magnetic islands ascend rapidly and saturate again for both static and dynamic cases.But the saturated island width of the dynamic case is smaller than that of the static case because the magnetic islands in the dynamic case rotate due to strong asymmetric distribution of the bootstrap current in the vicinity of the X-points.
文摘Methyl methoxyacetate(MMAc)and methyl formate(MF)can be produced directly by heterogeneous zeolite-catalyzed carbonylation and disproportionation of dimethoxymethane(DMM),with near 100%selectivity for each process.Despite continuous research efforts,the insight into the reaction mechanism and kinetics theory are still in their nascent stage.In this study,ZEO-1 material,a zeolite with up to now the largest cages comprising 16×16-MRs,16×12-MRs,and 12×12-MRs,was explored for DMM carbonylation and disproportionation reactions.The rate of MMAc formation based on accessible Brönsted acid sites is 2.5 times higher for ZEO-1(Si/Al=21)relative to the previously investigated FAU(Si/Al=15),indicating the positive effect of spatial separation of active sites in ZEO-1 on catalytic activity.A higher MF formation rate is also observed over ZEO-1 with lower activation energy(79.94 vs.95.19 kJ/mol)compared with FAU(Si/Al=30).Two types of active sites are proposed within ZEO-1 zeolite:Site 1 located in large cages formed by 16×16-MRs and 16×12-MRs,which is active predominantly for MMAc formation,and Site 2 located in smaller cages for methyl formate/dimethyl ether formation.Kinetics investigation of DMM carbonylation over ZEO-1 exhibit a first-order dependence on CO partial pressure and a slightly inverse-order dependence on DMM partial pressure.The DMM disproportionation is nearly first-order dependence on DMM partial pressure,while it reveals a strongly inverse dependence with increasing CO partial pressure.Furthermore,ZEO-1 exhibits good catalytic stability,and almost no deactivation is observed during the more than 70 h test with high carbonylation selectivity of above 89%,due to the well-enhanced diffusion property demonstrated by intelligent-gravimetric analysis.
文摘Phosphoric acid is a key ingredient in fertilizer production and contains many rare earth elements(REEs).Recovering REEs from phosphoric acid can prevent the accumulation of these elements in the soil and help bridge the gap between supply and demand.In this concern,a new material called Si-6G PAMAMPPAAM dendrimers modified silica gel terminated with phenylphosphonic acid-amide moieties was developed and its ability to adsorb Nd(Ⅲ)and Er(Ⅲ)from the phosphoric acid solution was investigated.K inetics and isotherm of the uptake process were investigated to explo re the so rption characte ristics.The attained results show that both metal ions exhibit the same adsorption performance,and the uptake process is depicted as a chemisorption,monolayer,uniform,and homogeneous process.The equilibrium state is achieved within 120 min,and the maximum uptake capacity is 16.7 mg Nd(Ⅲ)/g,and 14.0 mg Er(Ⅲ)/g.Sorption thermodynamics is an endothermic,spontaneous,and feasible uptake process.Nitric acid(1.0 mol/L)is found to be efficient for adsorbing about 94.3%and 92.5%of neodymium(Ⅲ)and erbium(Ⅲ)respectively,and the prepared Si-6G PAMAM-PPAAM demonstrates excellent stability over five consecutive sorption/desorption cycles.Preliminary tests on commercial phosphoric acid demonstrate that Si-6G PAMAM-PPAAM retains its effective REEs uptake from a complex comm ercial phosph oric acid solution.
文摘To accurately analyze proppant transport in rough intersecting fractures and elucidate the interaction mechanisms among liquid,particles,and rough walls,this study reconstructed a numerical model of fractures in inhomogeneous reservoirs with varying brittleness index(BI).Various auto-correlation Gaussian rough fracture models were created using Matlab to assess roughness through the fractal dimension method.This research innovatively combined Boolean operations to establish three-dimensional rough fracture models,incorporating(Computational Fluid Dynamics)CFD-DEM(Discrete Element Method)with a bidirectional method for cosimulation.The proppant transport in fractures was categorized into three zones based on the difference in the turbulent kinetic energy.Artificially induced fracture roughness increases fluid retention and turbulence,causing plugging effects and limiting proppant flow into branch fractures.Additionally,compared with the superior deposition and significant support effects of the spherical proppant,the low-sphericity proppant traveled farther under fracturing fluid,inducing more pronounced plugging near curved fracture intersections;the variation in fracture intersection angles primarily impacted the wall shear stress within the flow field,indicating smaller angles led to higher shear energy at the intersection.Compared with the intersection angle of 30°,the height and area deposited in the 90 branch fracture increased by 52.25%and 65.33%,respectively:notably,injecting proppant from smaller to larger particles(S:M:L)and a low velocity effectively ensured fracture conductivity near the wellbore at joint roughness coefficient(JRC)≥46 while achieving satis-factory placement in the branch fracture,making it a recommended approach.
基金supported by the Beijing Natural Science Foundation Key Research Program(Grant Z240026)the Beijing National Laboratory for Molecular Sciences.
文摘Electrocatalysis has been investigated as a promising strategy to utilize green electricity to produce renewable fuels,valuable chemicals,and treat pollutants.Electrode kinetic analysis is a potent technique in interrogating reaction mechanisms and evaluating the electrocatalysts.Electron transfer(ET)and proton‐coupled electron transfer(PCET)processes are widely present in reaction networks of electrocatalysis.pH dependence of the kinetics is frequently employed to evaluate whether an elementary step involves proton participation,which is determined by both the reversibility and the specific reactants of electrode reactions.In this article,we discuss the pH dependence of two widely used formulations of the Butler–Volmer kinetics for a model PCET step and highlight a potential pitfall in kinetic analysis.This work aims to provide guiding principles for distinguishing ET and PCET steps via kinetic measurements in electrolytes in a broad range pH values.
