Since photo-induced polymerization of the ultra-violet(UV)-curing adhesive from a fluid state to a solid state is an exothermic process,the UV curing exothermic behavior can be regarded as a potential evaluation metho...Since photo-induced polymerization of the ultra-violet(UV)-curing adhesive from a fluid state to a solid state is an exothermic process,the UV curing exothermic behavior can be regarded as a potential evaluation methodology to analyze UV-curing kinetics.Herein,a fiber Bragg grating(FBG)-based UV curing exothermic behavior monitoring is proposed to evaluate the UV-curing dynamic process and analyze a series of thermal and mechanical properties changes during curing.The exothermic behavior of the UV curing adhesive during curing and the feasibility of FBG-based curing kinetic analysis scheme are verified experimentally,full cycle cure monitoring of the UV curing adhesive can be realized by this FBG-based curing kinetic analysis scheme,and the UV-curing kinetics of four different types of the UV curing adhesive are corresponding to different exothermic behaviors.Compared with curing process evaluation based on refractive index variation,this FBG-based exothermic behavior monitoring has the ability to extract more details of the curing process,and some curing stages with negligible refractive index changes also can be distinguished.By using this proposed scheme,the UV-curing dynamic process and multiple characteristic parameters,such as curing time,time constant,transient temperature rise,and residual stress,can be evaluated,which may contribute to evaluating and analyzing UV-curing kinetics more comprehensively.展开更多
Under the backdrop of“Carbon Peak and Carbon Neutrality”(dual carbon)goal in China,the methane-carbon dioxide reforming reaction has attracted considerable attention due to its environmental benefits of converting t...Under the backdrop of“Carbon Peak and Carbon Neutrality”(dual carbon)goal in China,the methane-carbon dioxide reforming reaction has attracted considerable attention due to its environmental benefits of converting two greenhouse gases(methane and carbon dioxide)into syngas and its promising industrial applications.Nickel(Ni)-based catalysts,with high catalytic activity,low cost,and abundant resources,are considered ideal candidates for industrial applications.In this article,three reaction kinetic models were briefly introduced,namely the Power-Law(PL)model,the Eley-Rideal(ER)model,and the Langmuir-Hinshelwood-Hougen-Watson(LHHW)model.Based on the LHHW model,the reaction kinetics and mechanisms of different catalytic systems were systematically discussed,including the properties of supports,the doping of noble metals and transition metals,the role of promoters,and the influence of the geometric and electronic structures of Ni on the reaction mechanism.Furthermore,the kinetics of carbon deposition and elimination on various catalysts were analyzed.Based on the reaction rate expressions for carbon elimination,the reasons for the high activity of transition metal iron(Fe)-doped catalysts and core-shell structured catalysts in carbon elimination were explained.Based on the detailed collation and comparative analysis of the reaction mechanisms and kinetic characteristics across diverse Ni-based catalytic systems,a theoretical guidance for the designing of high-performance catalysts was provided in this work.展开更多
The leaching process and kinetic behavior of lepidolite in hydrochloric acid were explored systematically.The influence of leaching conditions on the leaching efficiency of valuable metals in lepidolite was investigat...The leaching process and kinetic behavior of lepidolite in hydrochloric acid were explored systematically.The influence of leaching conditions on the leaching efficiency of valuable metals in lepidolite was investigated.Under optimized conditions,the leaching efficiencies of Li,K,Rb,Cs and Al are 92.02%,93.31%,88.59%,86.75%and 81.07%,respectively.Kinetics research results show that the leaching process conforms to the shrinking core model that is under the mixed control of chemical reaction and diffusion through the solid product layer.In addition,the contribution of solid product layer diffusion to the leaching gradually expands as the temperature rises,but it is still significantly less than the contribution of chemical reaction.Cost saving in the neutralizing agent and leaching processes makes hydrochloric acid an economical leaching agent for lepidolite.Finally,the Li2CO3 product with a purity of 99.89%was synthesized from the hydrochloric acid leachate.展开更多
The volatilization characteristics and kinetic mechanisms of arsenic were investigated in the temperature range of 623−773 K and pressure ranges of 10−10000 Pa.The experimental results reveal that the evaporation rate...The volatilization characteristics and kinetic mechanisms of arsenic were investigated in the temperature range of 623−773 K and pressure ranges of 10−10000 Pa.The experimental results reveal that the evaporation rate increases with increasing temperature and decreasing pressure.Surface reaction control dominates at low pressures(<100 Pa),whereas diffusion control dominates at high pressures(>5000 Pa).The evaporation behavior is successfully described by an Arrhenius-type model for temperature dependence and Logistic model for pressure dependence.Key kinetic parameters,including the critical pressure,maximum evaporation rate and evaporation coefficient,were calculated.The evaporation coefficient varies between 0.010 and 0.223,and the critical pressures vary between 281 and 478 Pa with temperature.展开更多
Sodium-ion batteries(SIBs)represent a highly promising class of energy storage devices.Enhancing SIBs performance necessitates innovative anode material development to overcome persistent challenges associated with th...Sodium-ion batteries(SIBs)represent a highly promising class of energy storage devices.Enhancing SIBs performance necessitates innovative anode material development to overcome persistent challenges associated with the large ionic radius of Na^(+),namely significant electrode volumetric expansion and sluggish reaction kinetics.Herein,a macroporous bimetallic(Co,Fe)selenide containing abundant heterojunction interfaces encapsulated into a carbon framework(M-CoSe_(2)/FeSe_(2)@C)is prepared by combining an in-situ crystallization strategy with carbonization-selenization treatment.The structural characterization reveals that the resulting M-CoSe_(2)/FeSe_(2)@C possesses a well-defined porous architecture with internal CoSe_(2)-FeSe_(2) nanoparticles encapsulated by an external carbon matrix.This configuration not only enhances electrical conductivity but also stabilizes the composite structure throughout sodiation/desodiation cycling.Evaluated as an anode in SIBs,the M-CoSe_(2)/FeSe_(2)@C electrode delivers outstanding cycling stability(retaining 455.0 mA h g^(−1) at 0.2 A g^(−1) after 100 cycles)and exceptional rate capability(285.6 mA h g^(−1) at 10 A g^(−1)).These superior properties are primarily attributed to the high density of interphase boundaries generated by the dual-phase configuration.Combined experimental and theoretical investigations demonstrate that these boundaries,particularly regions of high electron density on the FeSe_(2) side,kinetically favor Na^(+)adsorption,thereby accelerating sodium storage kinetics.Furthermore,multi-step electrochemical reaction mechanisms within the composite were elucidated through in-situ and ex-situ characterization analyses.展开更多
The hydrogen reduction kinetics of tungsten trioxide(WO_(3))was investigated via non-isothermal thermogravimetric analysis.Under the local gas-solid reduction conditions,the particle morphology of tungsten powders was...The hydrogen reduction kinetics of tungsten trioxide(WO_(3))was investigated via non-isothermal thermogravimetric analysis.Under the local gas-solid reduction conditions,the particle morphology of tungsten powders was found to be consistent with that of raw material WO_(3).The removal of oxygen from tungsten oxide during hydrogen reduction led to the formation of porous structures between the reduced particles,which were obviously different from the polyhedral single-crystal configuration of tungsten powders obtained via chemical vapor deposition.Moreover,the two-stage hydrogen reduction mechanisms of WO_(3) under the local gas-solid reduction conditions can be described using the composite autocatalytic function.The activation energies of the first and second stages of the hydrogen reduction of WO_(3) were determined to be 121 and 135 kJ/mol,respectively.展开更多
The crystallization and aggregation characteristics of the active layer components in organic solar cells(OSCs)are one of the core factors determining photovoltaic performance,influencing the entire process from light...The crystallization and aggregation characteristics of the active layer components in organic solar cells(OSCs)are one of the core factors determining photovoltaic performance,influencing the entire process from light absorption to charge separation,transport,and ultimately charge collection.Dynamic changes in crystallization and aggregation states can also disrupt the microstructure of the active layer,thus shortening the lifetime of the cell.In this study,a morphology modulation strategy is proposed to regulate the crystallization kinetics of non-fullerene acceptors by employing the polymer molecule PYIT as a nucleating agent.An appropriate amount of PYIT was first completely dissolved with the non-fullerene acceptor Y6 and left to stand for 24 h,followed by the fabrication of layer-by-layer processed OSCs.Experiments demonstrated that high crystallinity of PYIT allows it to act as a crystallization nucleus,promoting the crystallization,orientation consistency,and ordered stacking of the acceptor.These nanoscale structural optimizations facilitate efficient charge transport,enhance exciton dissociation efficiency,and suppress unfavorable energetic disorder.Consequently,not only was the power conversion efficiency(PCE)of D18-Cl/Y6-based layer-by-layer processed OSC increased from 18.08%to 19.13%,but the atmospheric stability and long-term lifetime of the OSCs were also significantly improved.Notably,this strategy is also applicable to indoor OSCs,and the PYIT-optimized device can achieve a PCE of 27.0%under 1000 lux light-emitting diode(LED,3200K)irradiation,which is superior to that of the control device(24.2%).This work develops a crystal engineering strategy that is able to simultaneously optimize the microscopic morphology and charge dynamics properties in OSCs,thereby achieving simultaneous improvement in efficiency and stability.展开更多
This study explores the thin-layer convective solar drying of Marrubium vulgare L.leaves under conditions typical of sun-rich semi-arid climates.Drying experiments were conducted at three inlet-air temperatures(40℃,5...This study explores the thin-layer convective solar drying of Marrubium vulgare L.leaves under conditions typical of sun-rich semi-arid climates.Drying experiments were conducted at three inlet-air temperatures(40℃,50℃,60℃)and two air velocities(1.5 and 2.5 m·s^(-1))using an indirect solar dryer with auxiliary temperature control.Moisture-ratio data were fitted with eight widely used thin-layer models and evaluated using correlation coefficient(r),root-mean-square error(RMSE),and Akaike information criterion(AIC).A complementary heattransfer analysis based on Reynolds and Prandtl numbers with appropriate Nusselt correlations was used to relate flow regime to drying performance,and an energy balance quantified the relative contributions of solar and auxiliary heat.The logarithmic model consistently achieved the lowest RMSE/AIC with r>0.99 across all conditions.Higher temperature and air velocity significantly reduced drying time during the decreasing-rate period,with no constantrate stage observed.On average,solar input supplied the large majority of the thermal demand,while the auxiliary heater compensated short irradiance drops to maintain setpoints.These findings provide a reproducible dataset and a modelling benchmark for M.vulgare leaves,and they support energy-aware design of hybrid solar dryers formedicinal plants in sun-rich regions.展开更多
Inorganic perovskite solar cells(IPSCs),due to their suitable bandgap and superior thermal stability,are ideal candidates for tandem solar cells combined with silicon.However,the development of inorganic perovskite so...Inorganic perovskite solar cells(IPSCs),due to their suitable bandgap and superior thermal stability,are ideal candidates for tandem solar cells combined with silicon.However,the development of inorganic perovskite solar cells has been hindered by suboptimal crystallization dynamics that generate detrimental defects in the perovskite lattice.Here,we propose 4-Methoxyphenylphosphonic Acid(4MPA)as a multifunctional additive to address this challenge.P=O in 4MPA establish strong coordination with undercoordinated Pb^(2+),while-OH engage in O...H-O hydrogen bonding interactions with DMSO,effectively weakening the solvent-[PbX_(6)]^(4-)octahedron interaction.This dual functionality facilitates complete and rapid DMA^(+)-to-Cs^(+)cation exchange while regulating crystallization kinetics,thereby optimizing crystal growth.Furthermore,π-π interactions between benzene rings significantly enhance the moisture resistance of the perovskite layer.The optimized device demonstrates a power conversion efficiency(PCE)of 21.35%,with unencapsulated devices retaining 93,63%of their initial efficiency after 200-hour continuous operation under ambient conditions(35%relative humidity).展开更多
This study investigates four Late Permian Gondwana coals from the Raniganj sub-basin,Damodar Valley and three Early Permian Gondwana coals from the Talcher sub-basin,Mahanadi Valley.The study aims to characterize the ...This study investigates four Late Permian Gondwana coals from the Raniganj sub-basin,Damodar Valley and three Early Permian Gondwana coals from the Talcher sub-basin,Mahanadi Valley.The study aims to characterize the kerogen type,hydrocarbon generation potential,thermal maturity,and organic matter composition,as well as to explore the impact of organic matter characteristics on kerogen kinetic parameters,utilizing multi proxy approach.The study further investigates the influence of the mineral matrix on kerogen decomposition kinetics.Based on the Rock-Eval parameters,Fourier transform infrared spectroscopy(FTIR)parameters,and vitrinite reflectance(R_(o)),the kerogen is primarily classified as immature/early mature TypeⅢkerogen derived from terrestrial land plants,with minor contribution from TypeⅡkerogen having mainly gas generating potential.The source of the organic matter,as determined by stable carbon isotopic composition(δ^(13)C_(org))values and C/N ratios indicates a primary input from C_(3) terrestrial plants.The presence of enriched collotelinites and liptinites,such as sporinite and resinite,provides evidence for the input of terrestrial higher plants,including both herbaceous and arborescent species.Various indices derived from maceral abundances,including the gelification index(GI),tissue preservation index(TPI),and vegetation index(VI),collectively indicate diverse depositional conditions which range from wet forest swamps to shallow water-covered wet forest swamps and even dry forest swamps.The variation in vitrinite macerals influenced the kerogen type and consequently impacted the kinetic parameters,viz.the distribution of activation energies(E_(a)),kerogen transformation ratio(KTR),and hydrocarbon generation rate(HGR).Among the Talcher coals,shaly coals exhibit different kerogen type and kerogen transformation.This dissimilarity can be attributed to variable maceral compositions.Unlike the Talcher samples,all Raniganj samples show consistent kinetic behaviour despite their sample type(coal/shaly coal)or kerogen type(TypeⅢ/mixed TypeⅡ/Ⅲ)owing to comparable liptinite/vitrinite maceral composition.This study reveals that whilst the presence of mineral matrix shifts the apparent E_(a) of kerogen through interactions like adsorption and catalysis,it does not significantly affect the kerogen type,HGR,or KTR of the studied coals.展开更多
In this study,copper extraction from low-grade oxide-sulfide ores was investigated using a leaching method combined with response surface methodology(RSM)to optimize operational conditions and assess leaching kinetics...In this study,copper extraction from low-grade oxide-sulfide ores was investigated using a leaching method combined with response surface methodology(RSM)to optimize operational conditions and assess leaching kinetics.Given copper's extensive industrial applications,sustainable recovery from low-grade ores is critical.Five key parameters-acid concentration,leaching time,particle size,temperature,and solids percentage-were identified as major influences on copper recovery.The results revealed that leaching time and solids percentage,along with interactions between temperature-time and temperature-solids percentage,had the most significant effects.Optimal conditions for 80% copper recovery while minimizing iron recovery below 3% included an acid concentration of 1.21 mol L^(-1),a leaching time of 108 min,a particle size of 438μm,a temperature of 45℃,and a solids percentage of 18.2%.Leaching kinetics were analyzed using shrinking core models,with the Dickinson model best describing the process,showing an activation energy of 32.63 kJ mol^(-1),indicative of mixed diffusion and chemical reaction control.The final kinetic model effectively predicted the influence of key parameters.These findings highlight the importance of optimizing process variables and selecting suitable kinetic models to enhance extraction efficiency,reduce costs,and improve sustainability in copper recovery.展开更多
This study proposes to use the unconfined compressive strength(UCS)and the bender element(BE)tests for determining the strength and the initial small-strain shear modulus of Bangkok soft marine clay improved by cement...This study proposes to use the unconfined compressive strength(UCS)and the bender element(BE)tests for determining the strength and the initial small-strain shear modulus of Bangkok soft marine clay improved by cement and polyester fibers.This study varies the content of admixed cement(1%–20%)and polyester fibers(0–20%),including the curing time(3–28 d)for preparing 360 samples.Moreover,this study uses the Michaelis-Menten kinetics concept to model cement hydration saturation.From the study,it is concluded as follows.The modelled results reveals that at least 10%cement and 1%polyester fiber are recommended to attain the 28-d UCS standards(294 kPa)for highway subgrade materials in Thailand.This also fulfils sustainable construction due to reducing normal-use cement from 20%to 10%.Unfortunately,the addition of polyester fibers into the Bangkok clay with at least 5%cement reduces shear modulus by 1.12–1.32 times.The Abram's relationship between shear modulus and the mixing-water-to-cement ratio is found time-dependent.From the composite theory,the BE detects the polyester fiber zone as a defect in the Bangkok clay(matrix)with 5%–20%cement.So,the 28-d shear modulus in the polyester fiber zone is negative(up to0.034 MPa for 20%fiber),similar to softening phenomenon in concrete cracking(negative stiffness).For the 28-d shear modulus of fiber zone,the optimum cement content is around 2%for the positive influences of polyester fibers.Experimentally,the timedependent normalized UCS for 10%and 20%cement is compatible with other studies,and its development rate increases with the cement content as 0.3017,0.3172 and 0.3204 for 5%,10%and 20%cement,respectively.The 28-d relationship between shear modulus and UCS shows that low-cement soft clay requires high polyester fiber content(5%–20%)to activate UCS improvement.However,the soft clay with enough cement(20%)causes the uniformly distributed UCS improvement.展开更多
Layered double hydroxides(LDHs)hold great promise as cathode materials for aqueous zinc-ion batteries(AZIBs).Nevertheless,they also face challenges of sluggish kinetics and rapid capacity loss.Herein,a conformational ...Layered double hydroxides(LDHs)hold great promise as cathode materials for aqueous zinc-ion batteries(AZIBs).Nevertheless,they also face challenges of sluggish kinetics and rapid capacity loss.Herein,a conformational entropy regulation strategy has been applied to surmount the shortcomings.A medium-entropy iron-based metal organic framework(MIL-88)derived NiCoFeInZnV-based layered double hydroxide with carbon loaded(ME-NiCoFeInZnV-LDH/C)has been first proposed and prepared with a designed method.The increased entropy optimizes electron conductivity and alleviates structure alteration and diffusion barrier during interactions with charge carriers,due to electron-induced effect and“cocktail”effect.Moreover,the nanosheet assembled hollow prismatic structures could homogenize flux distribution and electric field distribution.Therefore,the electrochemical kinetics,crystal structure stability,and activity could be dramatically improved.Leveraging the advantages of structure and composition regulation,Zn||ME-NiCoFeInZnV-LDH/C zinc battery delivers high specific capacities,rate performance,and cycling stability.This work proposes a novel and feasible medium-entropy strategy to prepare a high-performance cathode for advanced AZIBs,which is of prominent significance for the development of charge storage devices.展开更多
Single-pass and double-pass high-temperature deformation experiments were conducted on 40Cr10Si2Mo steel using a Gleeble-3500 thermal simulator.The static recrystallization(SRX)behavior and recrystallization mechanism...Single-pass and double-pass high-temperature deformation experiments were conducted on 40Cr10Si2Mo steel using a Gleeble-3500 thermal simulator.The static recrystallization(SRX)behavior and recrystallization mechanisms of 40Cr10Si2Mo steel were investigated under deformation temperatures of 900-1100℃,deformation strains of 10%,20%,and 30%,and inter-pass times of 1-120 s.A static recrystallization fraction model was developed.The results showed that the SRX volume fraction increased with higher deformation temperature,larger deformation amount,and longer inter-pass time,with the deformation temperature having the most significant effect on SRX.During the deformation process,different process parameters led to different internal deformation mechanisms of the material.Static recovery and continuous static recrystallization(CSRX)dominated deformation at lower temperatures through progressive lattice rotation.In comparison,at higher temperatures,the deformation mechanism was dominated by CSRX and discontinuous static recrystallization(DSRX).The nucleation mechanisms of the SRX process were grain boundary bulging nucleation and subgrain merging nucleation,with grain boundary bulging present under all conditions.Subgrain merging nucleation could provide an additional nucleation mode at lower deformation temperatures or lower deformation amounts.Based on the traditional Avarmi equation,a modified model coefficient was used to establish the SRX kinetic model for 40Cr10Si2Mo steel.The linear correlation coefficient R^(2) between the predicted and experimental static recrystallization volume fraction was 0.96702,indicating high prediction accuracy.展开更多
Cadmium(Cd)contamination in soils poses substantial environmental and health risks globally,with manganese(Mn)playing a crucial role in regulating Cd mobility through soil adsorption processes and shared crop uptake p...Cadmium(Cd)contamination in soils poses substantial environmental and health risks globally,with manganese(Mn)playing a crucial role in regulating Cd mobility through soil adsorption processes and shared crop uptake pathways.While the importance of understanding Cd-Mn dynamics in soils is widely recognized,quantitative assessments of their correlated desorption processes remain limited.This study employed diffusive gradients in thin-films(DGT)technique combined with DGT-induced fluxes in soils(DIFS)modeling to investigate Cd and Mn availability and desorption dynamics in karst soils from Guangxi,southwestern China.The soil solution concentrations ranged from 0.23–1.82μg/L for Cd and 1.29–8.41 mg/L for Mn.DGT measurements demonstrated nonlinear accumulation patterns for both metals over 48 h duration.DIFS modeling yielded distribution coefficients(Kdl)ranging from 2.50 to 807 mL/g and response time(Tc)between 1.27 and 425 s for both metals.Solid phase resupply was limited by desorption rates of 5.38–229×10^(−5)/s,providing unprecedented insight into the kinetics of metal release in these soils.Analysis of metal desorption rate ratios(k−1-Mn/k−1-Cd)indicated that soil organic matter content,clay content,pH,and metal contents collectively control Cd and Mn desorption kinetics,leading to distinct desorption patterns across soils with varying physicochemical properties.These findings demonstrate rapid equilibrium reestablishment and desorption-limited resupply characteristics of Cd and Mn in karst soils,advancing understanding of correlative metal behaviors in these unique geological settings.展开更多
In this work,silicon-carbon hybrid materials were adopted as an example to illustrate the novel strategy to in situ construct heterostructure with adjustable microstructure.Based on the temperature-dependent thermodyn...In this work,silicon-carbon hybrid materials were adopted as an example to illustrate the novel strategy to in situ construct heterostructure with adjustable microstructure.Based on the temperature-dependent thermodynamics and kinetics of reaction between Si and C,the processes for Si nanocrystals growth and C decoration were coupled at different zones of plasma flame according to its temperature and velocity fields by theoretical modeling,aiming to intentionally suppress the formation of undesirable carbide,and enable adjusting the microstructure of each counterpart separately in transient process.As a result,well-controlled Si/C nanocomposites,including nanospheres and nanowires with core-shell structures,were achieved,and this continuous and in-flight route is also potential for large-scale production.Further investigation on the electrochemical properties highlights the advantage of as proposed strategy to efficiently construct heterostructures with superior performance for various applications.展开更多
As a refractory iron ore,the clean and efficient beneficiation of limonite is crucial for ensuring a sustainable long-term supply of iron metal.In this study,the microwave fluidization magnetization roasting of limoni...As a refractory iron ore,the clean and efficient beneficiation of limonite is crucial for ensuring a sustainable long-term supply of iron metal.In this study,the microwave fluidization magnetization roasting of limonite was explored.The micromorphology,microstructure,and mineral phase transformation of the roasted products were analyzed using a scanning electron microscope,an automatic surface area and porosity analyzer,an X-ray diffractometer,and a vibrating sample magnetometer.Kinetic analysis was also conducted to identify the factors limiting the roasting reaction rate.Microwave fluidization roasting significantly increased the specific surface area of limonite,increased the opportunity of contact between CO and limonite,and accelerated the transformation from FeO(OH)toα-Fe_(2)O_(3)and then to Fe_(3)O_(4).In addition,the water in the limonite ore and the newly formed magnetite exhibited a strong microwave absorption capacity,which has a certain activation effect on the reduction roasting of limonite.The saturation magnetization and maximum specific magnetization coefficient increased to 23.08 A·m^(2)·kg^(-1)and 2.50×10^(-4)m^(3)·kg^(-1),respectively.The subsequent magnetic separation of the reconstructed limonite yielded an iron concentrate with an Fe grade of 59.26wt%and a recovery of 90.07wt%.Kinetic analysis revealed that the reaction mechanism function model was consistent with the diffusion model(G(α)=α^(2)),with the mechanism function described as k=0.08208exp[-20.3441/(R_(g)T)].Therefore,microwave fluidization roasting shows significant potential in the beneficiation of limonite,offering a promising approach for the exploitation of refractory iron ores.展开更多
Designing catalysts with high catalytic activity and stability is the key to achieve the commercial application of MgH_(2).Herein,the sulfur doped Ti_(3)C_(2)(S-Ti_(3)C_(2))was successfully prepared by heat treatment ...Designing catalysts with high catalytic activity and stability is the key to achieve the commercial application of MgH_(2).Herein,the sulfur doped Ti_(3)C_(2)(S-Ti_(3)C_(2))was successfully prepared by heat treatment of Ti_(3)C_(2)MXene under Ar/H_(2)S atmosphere to facilitate the hydrogen release and uptake from MgH_(2).The S-Ti_(3)C_(2)exhibited pleasant catalytic effect on the hydriding/dehydriding kinetics and cyclic stability of MgH_(2).The addition of 5 wt%S-Ti_(3)C_(2)into MgH_(2)resulted in a reduction of 114℃in the starting dehydriding temperature compared to pure MgH_(2).MgH_(2)+5 wt%S-Ti_(3)C_(2)sample could quickly release 6.6 wt%hydrogen in 17 min at 220℃,and 6.8 wt%H_(2)was absorbed in 25 min at 200℃.Cyclic testing revealed that MgH_(2)+5 wt%S-Ti_(3)C_(2)system achieved a reversible hydrogen capacity of 6.5 wt%.Characterization analysis demonstrated that Ti-species(Ti0,Ti^(2+),Ti-S,and Ti^(3+))as active species significantly lowered the dehydrogenation temperature and promoted the re-/dehydrogenation kinetics of MgH_(2),and sulfur doping can effectively improve the stability of Ti0 and Ti^(3+),contributing to the improvement of cyclic stability of MgH_(2).This study provides strategy for the construction of catalysts for hydrogen storage materials.展开更多
This work reveals the significant effects of cobalt(Co)on the microstructure and impact toughness of as-quenched highstrength steels by experimental characterizations and thermo-kinetic analyses.The results show that ...This work reveals the significant effects of cobalt(Co)on the microstructure and impact toughness of as-quenched highstrength steels by experimental characterizations and thermo-kinetic analyses.The results show that the Co-bearing steel exhibits finer blocks and a lower ductile-brittle transition temperature than the steel without Co.Moreover,the Co-bearing steel reveals higher transformation rates at the intermediate stage with bainite volume fraction ranging from around 0.1 to 0.6.The improved impact toughness of the Co-bearing steel results from the higher dense block boundaries dominated by the V1/V2 variant pair.Furthermore,the addition of Co induces a larger transformation driving force and a lower bainite start temperature(BS),thereby contributing to the refinement of blocks and the increase of the V1/V2 variant pair.These findings would be instructive for the composition,microstructure design,and property optimization of high-strength steels.展开更多
Selective laser melting(SLM)is a cost-effective 3 D metal additive manufacturing(AM)process.However,AM 316 L stainless steel(SS)has different surface and microstructure properties as compared to conventional ones.Bori...Selective laser melting(SLM)is a cost-effective 3 D metal additive manufacturing(AM)process.However,AM 316 L stainless steel(SS)has different surface and microstructure properties as compared to conventional ones.Boriding process is one of the ways to modify and increase the surface properties.The aim of this study is to predict and understand the growth kinetic of iron boride layers on AM 316 L SS.In this study,the growth kinetic mechanism was evaluated for AM 316 L SS.Pack boriding was applied at 850,900 and 950℃,each for 2,4 and 6 h.The thickness of the boride layers ranged from(1.8±0.3)μm to(27.7±2.2)μm.A diffusion model based on error function solutions in Fick’s second law was proposed to quantitatively predict and elucidate the growth rate of FeB and Fe_(2)B phase layers.The activation energy(Q)values for boron diffusion in FeB layer,Fe_(2)B layer,and dual FeB+Fe_(2)B layer were found to be 256.56,161.61 and 209.014 kJ/mol,respectively,which were higher than the conventional 316 L SS.The findings might provide and open new directions and approaches for applications of additively manufactured steels.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.62275039 and 61705189)Fundamental Research Funds for the Central Universities,China(Grant No.DUT24MS022)State Key Laboratory of Advanced Optical Communication Systems and Networks,China(Grant No.2022GZKF001).
文摘Since photo-induced polymerization of the ultra-violet(UV)-curing adhesive from a fluid state to a solid state is an exothermic process,the UV curing exothermic behavior can be regarded as a potential evaluation methodology to analyze UV-curing kinetics.Herein,a fiber Bragg grating(FBG)-based UV curing exothermic behavior monitoring is proposed to evaluate the UV-curing dynamic process and analyze a series of thermal and mechanical properties changes during curing.The exothermic behavior of the UV curing adhesive during curing and the feasibility of FBG-based curing kinetic analysis scheme are verified experimentally,full cycle cure monitoring of the UV curing adhesive can be realized by this FBG-based curing kinetic analysis scheme,and the UV-curing kinetics of four different types of the UV curing adhesive are corresponding to different exothermic behaviors.Compared with curing process evaluation based on refractive index variation,this FBG-based exothermic behavior monitoring has the ability to extract more details of the curing process,and some curing stages with negligible refractive index changes also can be distinguished.By using this proposed scheme,the UV-curing dynamic process and multiple characteristic parameters,such as curing time,time constant,transient temperature rise,and residual stress,can be evaluated,which may contribute to evaluating and analyzing UV-curing kinetics more comprehensively.
基金Supported by Innovation Capability Support Program of Shaanxi(2024RS-CXTD-53,2024ZC-KJXX-096)the Key R&D Program of Shaanxi Province(2022QCY-LL-69)Xi’an Science and Technology Project(24GXFW0089)。
文摘Under the backdrop of“Carbon Peak and Carbon Neutrality”(dual carbon)goal in China,the methane-carbon dioxide reforming reaction has attracted considerable attention due to its environmental benefits of converting two greenhouse gases(methane and carbon dioxide)into syngas and its promising industrial applications.Nickel(Ni)-based catalysts,with high catalytic activity,low cost,and abundant resources,are considered ideal candidates for industrial applications.In this article,three reaction kinetic models were briefly introduced,namely the Power-Law(PL)model,the Eley-Rideal(ER)model,and the Langmuir-Hinshelwood-Hougen-Watson(LHHW)model.Based on the LHHW model,the reaction kinetics and mechanisms of different catalytic systems were systematically discussed,including the properties of supports,the doping of noble metals and transition metals,the role of promoters,and the influence of the geometric and electronic structures of Ni on the reaction mechanism.Furthermore,the kinetics of carbon deposition and elimination on various catalysts were analyzed.Based on the reaction rate expressions for carbon elimination,the reasons for the high activity of transition metal iron(Fe)-doped catalysts and core-shell structured catalysts in carbon elimination were explained.Based on the detailed collation and comparative analysis of the reaction mechanisms and kinetic characteristics across diverse Ni-based catalytic systems,a theoretical guidance for the designing of high-performance catalysts was provided in this work.
基金supported by the National Natural Science Foundation of China(No.52122407)the National Key Research&Development Program of China(No.2022YF2906200)the Science and Technology Innovation Program of Hunan Province,China(No.2022RC3048)。
文摘The leaching process and kinetic behavior of lepidolite in hydrochloric acid were explored systematically.The influence of leaching conditions on the leaching efficiency of valuable metals in lepidolite was investigated.Under optimized conditions,the leaching efficiencies of Li,K,Rb,Cs and Al are 92.02%,93.31%,88.59%,86.75%and 81.07%,respectively.Kinetics research results show that the leaching process conforms to the shrinking core model that is under the mixed control of chemical reaction and diffusion through the solid product layer.In addition,the contribution of solid product layer diffusion to the leaching gradually expands as the temperature rises,but it is still significantly less than the contribution of chemical reaction.Cost saving in the neutralizing agent and leaching processes makes hydrochloric acid an economical leaching agent for lepidolite.Finally,the Li2CO3 product with a purity of 99.89%was synthesized from the hydrochloric acid leachate.
基金Yunnan Fundamental Research Project,China(No.202201BE070001-056)。
文摘The volatilization characteristics and kinetic mechanisms of arsenic were investigated in the temperature range of 623−773 K and pressure ranges of 10−10000 Pa.The experimental results reveal that the evaporation rate increases with increasing temperature and decreasing pressure.Surface reaction control dominates at low pressures(<100 Pa),whereas diffusion control dominates at high pressures(>5000 Pa).The evaporation behavior is successfully described by an Arrhenius-type model for temperature dependence and Logistic model for pressure dependence.Key kinetic parameters,including the critical pressure,maximum evaporation rate and evaporation coefficient,were calculated.The evaporation coefficient varies between 0.010 and 0.223,and the critical pressures vary between 281 and 478 Pa with temperature.
基金support from the National Natural Science Foundation of China(Grant 51573058)funding provided through the Postdoctoral Fellowship Program(Grade C)of the China Postdoctoral Science Foundation(GZC20240629).
文摘Sodium-ion batteries(SIBs)represent a highly promising class of energy storage devices.Enhancing SIBs performance necessitates innovative anode material development to overcome persistent challenges associated with the large ionic radius of Na^(+),namely significant electrode volumetric expansion and sluggish reaction kinetics.Herein,a macroporous bimetallic(Co,Fe)selenide containing abundant heterojunction interfaces encapsulated into a carbon framework(M-CoSe_(2)/FeSe_(2)@C)is prepared by combining an in-situ crystallization strategy with carbonization-selenization treatment.The structural characterization reveals that the resulting M-CoSe_(2)/FeSe_(2)@C possesses a well-defined porous architecture with internal CoSe_(2)-FeSe_(2) nanoparticles encapsulated by an external carbon matrix.This configuration not only enhances electrical conductivity but also stabilizes the composite structure throughout sodiation/desodiation cycling.Evaluated as an anode in SIBs,the M-CoSe_(2)/FeSe_(2)@C electrode delivers outstanding cycling stability(retaining 455.0 mA h g^(−1) at 0.2 A g^(−1) after 100 cycles)and exceptional rate capability(285.6 mA h g^(−1) at 10 A g^(−1)).These superior properties are primarily attributed to the high density of interphase boundaries generated by the dual-phase configuration.Combined experimental and theoretical investigations demonstrate that these boundaries,particularly regions of high electron density on the FeSe_(2) side,kinetically favor Na^(+)adsorption,thereby accelerating sodium storage kinetics.Furthermore,multi-step electrochemical reaction mechanisms within the composite were elucidated through in-situ and ex-situ characterization analyses.
基金supported by the National Key Research&Development Program of China(No.2022YFC2904905)the National Natural Science Foundation of China(No.52274400)+1 种基金the Project of Zhongyuan Critical Metals Laboratory,China(No.GJJSGFZD202302)the Science and Technology Project of Henan Province,China(No.232102230044)。
文摘The hydrogen reduction kinetics of tungsten trioxide(WO_(3))was investigated via non-isothermal thermogravimetric analysis.Under the local gas-solid reduction conditions,the particle morphology of tungsten powders was found to be consistent with that of raw material WO_(3).The removal of oxygen from tungsten oxide during hydrogen reduction led to the formation of porous structures between the reduced particles,which were obviously different from the polyhedral single-crystal configuration of tungsten powders obtained via chemical vapor deposition.Moreover,the two-stage hydrogen reduction mechanisms of WO_(3) under the local gas-solid reduction conditions can be described using the composite autocatalytic function.The activation energies of the first and second stages of the hydrogen reduction of WO_(3) were determined to be 121 and 135 kJ/mol,respectively.
基金supported by the National Natural Science Foundation of China (NSFC grant no. 62474028, 52130304, and62222503)the Natural Science Foundation of Sichuan Province(2025ZNSFSC0037, 2025ZNSFSC1460, and 2024NSFSC1447)+1 种基金the National Key R and D Program of China (2023YFB2604101)sponsored by the Sichuan Province Key Laboratory of Display Science and Technology
文摘The crystallization and aggregation characteristics of the active layer components in organic solar cells(OSCs)are one of the core factors determining photovoltaic performance,influencing the entire process from light absorption to charge separation,transport,and ultimately charge collection.Dynamic changes in crystallization and aggregation states can also disrupt the microstructure of the active layer,thus shortening the lifetime of the cell.In this study,a morphology modulation strategy is proposed to regulate the crystallization kinetics of non-fullerene acceptors by employing the polymer molecule PYIT as a nucleating agent.An appropriate amount of PYIT was first completely dissolved with the non-fullerene acceptor Y6 and left to stand for 24 h,followed by the fabrication of layer-by-layer processed OSCs.Experiments demonstrated that high crystallinity of PYIT allows it to act as a crystallization nucleus,promoting the crystallization,orientation consistency,and ordered stacking of the acceptor.These nanoscale structural optimizations facilitate efficient charge transport,enhance exciton dissociation efficiency,and suppress unfavorable energetic disorder.Consequently,not only was the power conversion efficiency(PCE)of D18-Cl/Y6-based layer-by-layer processed OSC increased from 18.08%to 19.13%,but the atmospheric stability and long-term lifetime of the OSCs were also significantly improved.Notably,this strategy is also applicable to indoor OSCs,and the PYIT-optimized device can achieve a PCE of 27.0%under 1000 lux light-emitting diode(LED,3200K)irradiation,which is superior to that of the control device(24.2%).This work develops a crystal engineering strategy that is able to simultaneously optimize the microscopic morphology and charge dynamics properties in OSCs,thereby achieving simultaneous improvement in efficiency and stability.
文摘This study explores the thin-layer convective solar drying of Marrubium vulgare L.leaves under conditions typical of sun-rich semi-arid climates.Drying experiments were conducted at three inlet-air temperatures(40℃,50℃,60℃)and two air velocities(1.5 and 2.5 m·s^(-1))using an indirect solar dryer with auxiliary temperature control.Moisture-ratio data were fitted with eight widely used thin-layer models and evaluated using correlation coefficient(r),root-mean-square error(RMSE),and Akaike information criterion(AIC).A complementary heattransfer analysis based on Reynolds and Prandtl numbers with appropriate Nusselt correlations was used to relate flow regime to drying performance,and an energy balance quantified the relative contributions of solar and auxiliary heat.The logarithmic model consistently achieved the lowest RMSE/AIC with r>0.99 across all conditions.Higher temperature and air velocity significantly reduced drying time during the decreasing-rate period,with no constantrate stage observed.On average,solar input supplied the large majority of the thermal demand,while the auxiliary heater compensated short irradiance drops to maintain setpoints.These findings provide a reproducible dataset and a modelling benchmark for M.vulgare leaves,and they support energy-aware design of hybrid solar dryers formedicinal plants in sun-rich regions.
基金the financial support from the Yunnan Provincial Science and Technology Project at Southwest United Graduate School(Grant No.202302A0370009)the National Natural Science Foundation Joint Fund(Grant No.U21A2072)+4 种基金the National Science Foundation(Grant No.62274099)the Key Project of Tianjin Natural Science Foundation(Grant No.24JCZDJC01360)the China Higher Education Discipline Innovation Overseas Expert Introduction Project(Grant No.B16027)Tianjin Science and Technology Project(Grant No.24ZXZSSS00160)the Special Fund for Basic Scientific Research of the Central Universities。
文摘Inorganic perovskite solar cells(IPSCs),due to their suitable bandgap and superior thermal stability,are ideal candidates for tandem solar cells combined with silicon.However,the development of inorganic perovskite solar cells has been hindered by suboptimal crystallization dynamics that generate detrimental defects in the perovskite lattice.Here,we propose 4-Methoxyphenylphosphonic Acid(4MPA)as a multifunctional additive to address this challenge.P=O in 4MPA establish strong coordination with undercoordinated Pb^(2+),while-OH engage in O...H-O hydrogen bonding interactions with DMSO,effectively weakening the solvent-[PbX_(6)]^(4-)octahedron interaction.This dual functionality facilitates complete and rapid DMA^(+)-to-Cs^(+)cation exchange while regulating crystallization kinetics,thereby optimizing crystal growth.Furthermore,π-π interactions between benzene rings significantly enhance the moisture resistance of the perovskite layer.The optimized device demonstrates a power conversion efficiency(PCE)of 21.35%,with unencapsulated devices retaining 93,63%of their initial efficiency after 200-hour continuous operation under ambient conditions(35%relative humidity).
基金supported by the project grant,MLP-7016-28(EVB)of CSIR-NGRI,India。
文摘This study investigates four Late Permian Gondwana coals from the Raniganj sub-basin,Damodar Valley and three Early Permian Gondwana coals from the Talcher sub-basin,Mahanadi Valley.The study aims to characterize the kerogen type,hydrocarbon generation potential,thermal maturity,and organic matter composition,as well as to explore the impact of organic matter characteristics on kerogen kinetic parameters,utilizing multi proxy approach.The study further investigates the influence of the mineral matrix on kerogen decomposition kinetics.Based on the Rock-Eval parameters,Fourier transform infrared spectroscopy(FTIR)parameters,and vitrinite reflectance(R_(o)),the kerogen is primarily classified as immature/early mature TypeⅢkerogen derived from terrestrial land plants,with minor contribution from TypeⅡkerogen having mainly gas generating potential.The source of the organic matter,as determined by stable carbon isotopic composition(δ^(13)C_(org))values and C/N ratios indicates a primary input from C_(3) terrestrial plants.The presence of enriched collotelinites and liptinites,such as sporinite and resinite,provides evidence for the input of terrestrial higher plants,including both herbaceous and arborescent species.Various indices derived from maceral abundances,including the gelification index(GI),tissue preservation index(TPI),and vegetation index(VI),collectively indicate diverse depositional conditions which range from wet forest swamps to shallow water-covered wet forest swamps and even dry forest swamps.The variation in vitrinite macerals influenced the kerogen type and consequently impacted the kinetic parameters,viz.the distribution of activation energies(E_(a)),kerogen transformation ratio(KTR),and hydrocarbon generation rate(HGR).Among the Talcher coals,shaly coals exhibit different kerogen type and kerogen transformation.This dissimilarity can be attributed to variable maceral compositions.Unlike the Talcher samples,all Raniganj samples show consistent kinetic behaviour despite their sample type(coal/shaly coal)or kerogen type(TypeⅢ/mixed TypeⅡ/Ⅲ)owing to comparable liptinite/vitrinite maceral composition.This study reveals that whilst the presence of mineral matrix shifts the apparent E_(a) of kerogen through interactions like adsorption and catalysis,it does not significantly affect the kerogen type,HGR,or KTR of the studied coals.
基金Open Access funding enabled and organized by Projekt DEAL.
文摘In this study,copper extraction from low-grade oxide-sulfide ores was investigated using a leaching method combined with response surface methodology(RSM)to optimize operational conditions and assess leaching kinetics.Given copper's extensive industrial applications,sustainable recovery from low-grade ores is critical.Five key parameters-acid concentration,leaching time,particle size,temperature,and solids percentage-were identified as major influences on copper recovery.The results revealed that leaching time and solids percentage,along with interactions between temperature-time and temperature-solids percentage,had the most significant effects.Optimal conditions for 80% copper recovery while minimizing iron recovery below 3% included an acid concentration of 1.21 mol L^(-1),a leaching time of 108 min,a particle size of 438μm,a temperature of 45℃,and a solids percentage of 18.2%.Leaching kinetics were analyzed using shrinking core models,with the Dickinson model best describing the process,showing an activation energy of 32.63 kJ mol^(-1),indicative of mixed diffusion and chemical reaction control.The final kinetic model effectively predicted the influence of key parameters.These findings highlight the importance of optimizing process variables and selecting suitable kinetic models to enhance extraction efficiency,reduce costs,and improve sustainability in copper recovery.
基金allocated by National Science,Research and Innovation Fund(NSRF)King Mongkut's University of Technology North Bangkok(project no.KMUTNB-FF-67-B-44 and KMUTNB-FF-67-B-45)supported by the NSRF through the Program Management Unit for Human Resources&Institutional Development,Research and Innovation(grant no.B40G660036).
文摘This study proposes to use the unconfined compressive strength(UCS)and the bender element(BE)tests for determining the strength and the initial small-strain shear modulus of Bangkok soft marine clay improved by cement and polyester fibers.This study varies the content of admixed cement(1%–20%)and polyester fibers(0–20%),including the curing time(3–28 d)for preparing 360 samples.Moreover,this study uses the Michaelis-Menten kinetics concept to model cement hydration saturation.From the study,it is concluded as follows.The modelled results reveals that at least 10%cement and 1%polyester fiber are recommended to attain the 28-d UCS standards(294 kPa)for highway subgrade materials in Thailand.This also fulfils sustainable construction due to reducing normal-use cement from 20%to 10%.Unfortunately,the addition of polyester fibers into the Bangkok clay with at least 5%cement reduces shear modulus by 1.12–1.32 times.The Abram's relationship between shear modulus and the mixing-water-to-cement ratio is found time-dependent.From the composite theory,the BE detects the polyester fiber zone as a defect in the Bangkok clay(matrix)with 5%–20%cement.So,the 28-d shear modulus in the polyester fiber zone is negative(up to0.034 MPa for 20%fiber),similar to softening phenomenon in concrete cracking(negative stiffness).For the 28-d shear modulus of fiber zone,the optimum cement content is around 2%for the positive influences of polyester fibers.Experimentally,the timedependent normalized UCS for 10%and 20%cement is compatible with other studies,and its development rate increases with the cement content as 0.3017,0.3172 and 0.3204 for 5%,10%and 20%cement,respectively.The 28-d relationship between shear modulus and UCS shows that low-cement soft clay requires high polyester fiber content(5%–20%)to activate UCS improvement.However,the soft clay with enough cement(20%)causes the uniformly distributed UCS improvement.
基金the funding support from the National Natural Science Foundation of China(Grant No.52202217,52471222)the Natural Science Foundation of Jilin Province(Grant No.YDZJ202201ZYTS375).
文摘Layered double hydroxides(LDHs)hold great promise as cathode materials for aqueous zinc-ion batteries(AZIBs).Nevertheless,they also face challenges of sluggish kinetics and rapid capacity loss.Herein,a conformational entropy regulation strategy has been applied to surmount the shortcomings.A medium-entropy iron-based metal organic framework(MIL-88)derived NiCoFeInZnV-based layered double hydroxide with carbon loaded(ME-NiCoFeInZnV-LDH/C)has been first proposed and prepared with a designed method.The increased entropy optimizes electron conductivity and alleviates structure alteration and diffusion barrier during interactions with charge carriers,due to electron-induced effect and“cocktail”effect.Moreover,the nanosheet assembled hollow prismatic structures could homogenize flux distribution and electric field distribution.Therefore,the electrochemical kinetics,crystal structure stability,and activity could be dramatically improved.Leveraging the advantages of structure and composition regulation,Zn||ME-NiCoFeInZnV-LDH/C zinc battery delivers high specific capacities,rate performance,and cycling stability.This work proposes a novel and feasible medium-entropy strategy to prepare a high-performance cathode for advanced AZIBs,which is of prominent significance for the development of charge storage devices.
基金supported by the National Natural Science Foundation of China(Grant No.52174371)the National Key Research and Development Program of China(Grant No.2021YFB3501003)the Shaanxi Provincial Science and Technology Department Enterprise Joint Fund(Grant No.2021JLM-33).
文摘Single-pass and double-pass high-temperature deformation experiments were conducted on 40Cr10Si2Mo steel using a Gleeble-3500 thermal simulator.The static recrystallization(SRX)behavior and recrystallization mechanisms of 40Cr10Si2Mo steel were investigated under deformation temperatures of 900-1100℃,deformation strains of 10%,20%,and 30%,and inter-pass times of 1-120 s.A static recrystallization fraction model was developed.The results showed that the SRX volume fraction increased with higher deformation temperature,larger deformation amount,and longer inter-pass time,with the deformation temperature having the most significant effect on SRX.During the deformation process,different process parameters led to different internal deformation mechanisms of the material.Static recovery and continuous static recrystallization(CSRX)dominated deformation at lower temperatures through progressive lattice rotation.In comparison,at higher temperatures,the deformation mechanism was dominated by CSRX and discontinuous static recrystallization(DSRX).The nucleation mechanisms of the SRX process were grain boundary bulging nucleation and subgrain merging nucleation,with grain boundary bulging present under all conditions.Subgrain merging nucleation could provide an additional nucleation mode at lower deformation temperatures or lower deformation amounts.Based on the traditional Avarmi equation,a modified model coefficient was used to establish the SRX kinetic model for 40Cr10Si2Mo steel.The linear correlation coefficient R^(2) between the predicted and experimental static recrystallization volume fraction was 0.96702,indicating high prediction accuracy.
基金supported by the National Natural Science Foundation of China(Nos.42330703 and 42177194)Zhejiang Provincial Natural Science Foundation of China(No.LMS25D030001).
文摘Cadmium(Cd)contamination in soils poses substantial environmental and health risks globally,with manganese(Mn)playing a crucial role in regulating Cd mobility through soil adsorption processes and shared crop uptake pathways.While the importance of understanding Cd-Mn dynamics in soils is widely recognized,quantitative assessments of their correlated desorption processes remain limited.This study employed diffusive gradients in thin-films(DGT)technique combined with DGT-induced fluxes in soils(DIFS)modeling to investigate Cd and Mn availability and desorption dynamics in karst soils from Guangxi,southwestern China.The soil solution concentrations ranged from 0.23–1.82μg/L for Cd and 1.29–8.41 mg/L for Mn.DGT measurements demonstrated nonlinear accumulation patterns for both metals over 48 h duration.DIFS modeling yielded distribution coefficients(Kdl)ranging from 2.50 to 807 mL/g and response time(Tc)between 1.27 and 425 s for both metals.Solid phase resupply was limited by desorption rates of 5.38–229×10^(−5)/s,providing unprecedented insight into the kinetics of metal release in these soils.Analysis of metal desorption rate ratios(k−1-Mn/k−1-Cd)indicated that soil organic matter content,clay content,pH,and metal contents collectively control Cd and Mn desorption kinetics,leading to distinct desorption patterns across soils with varying physicochemical properties.These findings demonstrate rapid equilibrium reestablishment and desorption-limited resupply characteristics of Cd and Mn in karst soils,advancing understanding of correlative metal behaviors in these unique geological settings.
基金financially supported by the National Natural Science Foundation of China(No.52174342)Beijing Natural Sci-ence Foundation(No.2232044)Beijing Municipal Education Commission Research Plan General Project(No.KM202410005009).
文摘In this work,silicon-carbon hybrid materials were adopted as an example to illustrate the novel strategy to in situ construct heterostructure with adjustable microstructure.Based on the temperature-dependent thermodynamics and kinetics of reaction between Si and C,the processes for Si nanocrystals growth and C decoration were coupled at different zones of plasma flame according to its temperature and velocity fields by theoretical modeling,aiming to intentionally suppress the formation of undesirable carbide,and enable adjusting the microstructure of each counterpart separately in transient process.As a result,well-controlled Si/C nanocomposites,including nanospheres and nanowires with core-shell structures,were achieved,and this continuous and in-flight route is also potential for large-scale production.Further investigation on the electrochemical properties highlights the advantage of as proposed strategy to efficiently construct heterostructures with superior performance for various applications.
基金financially supported by the National Key Research and Development Program of China(No.2021YFC2901000)the National Natural Science Foundation of China(No.52104249)+1 种基金the Liaoning Joint Fund General Support Program Project(No.2023-MSBA-126)the Fundamental Research Funds for the Central Universities(No.N2401019)。
文摘As a refractory iron ore,the clean and efficient beneficiation of limonite is crucial for ensuring a sustainable long-term supply of iron metal.In this study,the microwave fluidization magnetization roasting of limonite was explored.The micromorphology,microstructure,and mineral phase transformation of the roasted products were analyzed using a scanning electron microscope,an automatic surface area and porosity analyzer,an X-ray diffractometer,and a vibrating sample magnetometer.Kinetic analysis was also conducted to identify the factors limiting the roasting reaction rate.Microwave fluidization roasting significantly increased the specific surface area of limonite,increased the opportunity of contact between CO and limonite,and accelerated the transformation from FeO(OH)toα-Fe_(2)O_(3)and then to Fe_(3)O_(4).In addition,the water in the limonite ore and the newly formed magnetite exhibited a strong microwave absorption capacity,which has a certain activation effect on the reduction roasting of limonite.The saturation magnetization and maximum specific magnetization coefficient increased to 23.08 A·m^(2)·kg^(-1)and 2.50×10^(-4)m^(3)·kg^(-1),respectively.The subsequent magnetic separation of the reconstructed limonite yielded an iron concentrate with an Fe grade of 59.26wt%and a recovery of 90.07wt%.Kinetic analysis revealed that the reaction mechanism function model was consistent with the diffusion model(G(α)=α^(2)),with the mechanism function described as k=0.08208exp[-20.3441/(R_(g)T)].Therefore,microwave fluidization roasting shows significant potential in the beneficiation of limonite,offering a promising approach for the exploitation of refractory iron ores.
基金supported by the National Natural Science Foundation of China(U22A20120,52071135,51871090,U1804135,and 52301269)the Natural Science Foundation of Hebei Province for Innovation Groups Program(C2022203003)Fundamental Research Funds for the Universities of Henan Province(NSFRF220201).
文摘Designing catalysts with high catalytic activity and stability is the key to achieve the commercial application of MgH_(2).Herein,the sulfur doped Ti_(3)C_(2)(S-Ti_(3)C_(2))was successfully prepared by heat treatment of Ti_(3)C_(2)MXene under Ar/H_(2)S atmosphere to facilitate the hydrogen release and uptake from MgH_(2).The S-Ti_(3)C_(2)exhibited pleasant catalytic effect on the hydriding/dehydriding kinetics and cyclic stability of MgH_(2).The addition of 5 wt%S-Ti_(3)C_(2)into MgH_(2)resulted in a reduction of 114℃in the starting dehydriding temperature compared to pure MgH_(2).MgH_(2)+5 wt%S-Ti_(3)C_(2)sample could quickly release 6.6 wt%hydrogen in 17 min at 220℃,and 6.8 wt%H_(2)was absorbed in 25 min at 200℃.Cyclic testing revealed that MgH_(2)+5 wt%S-Ti_(3)C_(2)system achieved a reversible hydrogen capacity of 6.5 wt%.Characterization analysis demonstrated that Ti-species(Ti0,Ti^(2+),Ti-S,and Ti^(3+))as active species significantly lowered the dehydrogenation temperature and promoted the re-/dehydrogenation kinetics of MgH_(2),and sulfur doping can effectively improve the stability of Ti0 and Ti^(3+),contributing to the improvement of cyclic stability of MgH_(2).This study provides strategy for the construction of catalysts for hydrogen storage materials.
基金supported by the National Natural Science Foundation of China(No.52271089)the financial support from the C hina Postdoctoral Science Foundation(No.2023M732192)。
文摘This work reveals the significant effects of cobalt(Co)on the microstructure and impact toughness of as-quenched highstrength steels by experimental characterizations and thermo-kinetic analyses.The results show that the Co-bearing steel exhibits finer blocks and a lower ductile-brittle transition temperature than the steel without Co.Moreover,the Co-bearing steel reveals higher transformation rates at the intermediate stage with bainite volume fraction ranging from around 0.1 to 0.6.The improved impact toughness of the Co-bearing steel results from the higher dense block boundaries dominated by the V1/V2 variant pair.Furthermore,the addition of Co induces a larger transformation driving force and a lower bainite start temperature(BS),thereby contributing to the refinement of blocks and the increase of the V1/V2 variant pair.These findings would be instructive for the composition,microstructure design,and property optimization of high-strength steels.
文摘Selective laser melting(SLM)is a cost-effective 3 D metal additive manufacturing(AM)process.However,AM 316 L stainless steel(SS)has different surface and microstructure properties as compared to conventional ones.Boriding process is one of the ways to modify and increase the surface properties.The aim of this study is to predict and understand the growth kinetic of iron boride layers on AM 316 L SS.In this study,the growth kinetic mechanism was evaluated for AM 316 L SS.Pack boriding was applied at 850,900 and 950℃,each for 2,4 and 6 h.The thickness of the boride layers ranged from(1.8±0.3)μm to(27.7±2.2)μm.A diffusion model based on error function solutions in Fick’s second law was proposed to quantitatively predict and elucidate the growth rate of FeB and Fe_(2)B phase layers.The activation energy(Q)values for boron diffusion in FeB layer,Fe_(2)B layer,and dual FeB+Fe_(2)B layer were found to be 256.56,161.61 and 209.014 kJ/mol,respectively,which were higher than the conventional 316 L SS.The findings might provide and open new directions and approaches for applications of additively manufactured steels.
