Photovoltaic(PV)systems in the field operate under complex,uncertain conditions rapid irradiance ramps,partial shading,temperature swings,surface soiling,and weak-grid disturbances including off-nominal frequency and ...Photovoltaic(PV)systems in the field operate under complex,uncertain conditions rapid irradiance ramps,partial shading,temperature swings,surface soiling,and weak-grid disturbances including off-nominal frequency and voltage distortion that degrade energy yield and power quality.We propose a drift-aware,power-quality-constrained MPPT framework that co-optimizes MPPT,PLL,and current-loop gains under stochastic frequency drift,while enforcing IEEE-519 limits(per-order Ih/IL and TDD)during optimization.Unlike energy-only or THD-only methods,the design target integrates PQ constraints into the objective and is validated across calibrated drift scenarios with explicit per-order and TDD reporting.Operating scenarios are calibrated to Cameroon’s Southern Interconnected Grid and city-specific profiles(Douala/Yaoundé),combining measured-style irradiance/temperature traces,partial-shading patterns,and stochastic frequency drift up to±0.8 Hz with synthetic contingencies.Across a 30-scenario campaign,the proposed controller achievesηMPPT=99.3%–99.6%(vs.98.6%Incremental Conductance and 97.8%Perturb-and-Observe),lowers DC-link ripple by 35%–48%,reduces oscillatory PCC power by≈41%,maintains THD≤2.5%(5%limit)and PF≥0.99,and shortens irradiance-step settling from 85–110 ms to 50–65 ms.Sensitivity to PLL bandwidth shows a broad optimum(≈60–90 Hz)with minimum THD/ripple,and ablations confirm that explicit drift weighting is pivotal to ripple and THD suppression without sacrificing yield.The approach is controller-agnostic,firmware-deployable,and generalizes to other converter-interfaced renewables;we outline a short hardware-/HIL-validation path for adoption in Sub-Saharan grids.展开更多
By the random distribution of metals in a single phase,entropy engineering is applied to construct dense neighboring active centers with diverse electronic and geometric structures,realizing the continuous optimizatio...By the random distribution of metals in a single phase,entropy engineering is applied to construct dense neighboring active centers with diverse electronic and geometric structures,realizing the continuous optimization of multiple primary reactions for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).Many catalysts developed through entropy engineering have been built in nearly equimolar ratios to pursue high entropy,hindering the identification of the active sites and potentially diluting the concentration of real active sites while weakening their electronic interactions with reaction intermediates.Herein,this work proposes an entropy-engineering strategy in metal nanoparticle-embedded nitrogen carbon electrocatalysts,implemented by entropy-engineered Prussian blue analogs(PBA)as precursors to enhance the catalytic activity of primary Cu-Fe active sites.Through the introduction of the micro-strains driven by entropy engineering,density functional theory(DFT)calculations and geometric phase analysis(GPA)using Lorentz electron microscopy further elucidate the optimization of the adsorption/desorption of intermediates.Furthermore,the multi-dimensional morphology and the size diminishment of the nanocrystals serve to expand the electrochemical area,maximizing the catalytic activity for both ORR and OER.Notably,the Zn-air battery assembled with CuFeCoNiZn-NC operated for over 1300 h with negligible decay.This work presents a paradigm for the design of low-cost electrocatalysts with entropy engineering for multi-step reactions.展开更多
Hydraulic fracturing is a commonly used stimulation technique for production optimization in various geological formations such as tight sandstone,shale,coal bed methane,and heat extraction in geothermal reservoirs.Br...Hydraulic fracturing is a commonly used stimulation technique for production optimization in various geological formations such as tight sandstone,shale,coal bed methane,and heat extraction in geothermal reservoirs.Breakdown pressure is a vital component in hydraulic fracture job design,which is affected by various parameters including rock strength and depth.Various methods including modelling and experimental approaches exist to quantify the breakdown pressure.There have been many strategies to reduce this pressure for efficient and economical hydraulic fracture jobs,especially when this pressure exceeds pump capacity.This study provides a detailed review of breakdown pressure in terms of fundamentals,influencing factors,and estimation approaches.In addition,different strategies are also presented to reduce the breakdown pressure along with cost analysis.Lastly,research gaps pertinent to this area are highlighted for emphasis in future research.Specifically,it has been found that high breakdown pressure is associated with challenges,but there are no comprehensive techniques and strategies to lower this pressure in formations with very high in situ stress profiles or complicated tectonic settings.Developing such methods is important to minimize operational failures,lower costs and reduce the environmental risks during reservoir exploitation.This study reviews the fundamentals,influencing factors,and estimation methods of breakdown pressure and provides a deep understanding of the strategies for its reduction.The study also presents the cost analyses,and highlights research gaps for future investigation.展开更多
NaNbO_(3)-based lead-free dielectric ceramics possess significant application prospects in the field of dielectric capacitors.However,their development is hindered by low recoverable energy storage density(W_(rec))and...NaNbO_(3)-based lead-free dielectric ceramics possess significant application prospects in the field of dielectric capacitors.However,their development is hindered by low recoverable energy storage density(W_(rec))and energy storage efficiency(η).Herein,novel NaNbO_(3)-based ceramics,(1-x)[0.7Na_(0.97)Sm_(0.01)NbO_(3)–0.3(Sr_(0.7)Bi_(0.2))(Ti_(0.8)Zr_(0.2))O_(3)]–xCaTiO_(3),were created by adding CaTiO_(3) linear dielectric,aiming to improve their energy storage performance(ESP).The phase structure,microstructure,dielectric properties,energy storage and charge–discharge performances of the ceramics were methodically analyzed.All components of the ceramics exhibit a perovskite structure consisting of two phases:antiferroelectric P-phase(AFE P)and antiferroelectric R-phase(AFE R),with the AFE R phase increasing as x rises.All ceramic surfaces exhibit clear grain morphology.The resultant ceramics have an appropriate dielectric constant and a small dielectric loss,which are beneficial for improving breakdown field strength(E_(b)).Finally,at an E_(b) of 470 kV/cm,0.85[0.7Na_(0.97)Sm_(0.01)NbO_(3)–0.3(Sr_(0.7)Bi_(0.2))(Ti_(0.8)Zr_(0.2))O_(3)]–0.15CaTiO_(3) ceramic achieves optimal ESP:W_(rec)=3.9 J/cm^(3),η=72.49%.In addition,it has remarkable stability with temperature and frequency in energy storage and displays ultrafast speed in the charge–discharge process(t_(0.9)=27 ns).展开更多
Energy density and safety are two crucial parameters when evaluating lithium-metal batteries(LMBs).Herein,we present an ultralight polymer-based current collector,incorporating flame-retardant materials,designed speci...Energy density and safety are two crucial parameters when evaluating lithium-metal batteries(LMBs).Herein,we present an ultralight polymer-based current collector,incorporating flame-retardant materials,designed specifically for thin lithium-metal anodes.Compared to the traditional copper current collector(8.96 mg cm^(-2),10μm thick),the polymer-based current collector(12μm thick)has a significantly lower areal density of 1.41 mg cm^(-2),i.e.,only one-sixth of the copper collector,thus enabling substantially higher energy densities.Accordingly,when employed in Li||NMC_(622)full-cells,the polymer-based current collector enables a specific energy of 449 Wh kg^(-1),representing a notable improvement of about14.5%compared to cells employing a classic copper current collector.The inclusion of Al(OH)_(3) as a flame retardant into the current collector suppresses flammability and,thereby,significantly improves the safety of the resulting LMBs.展开更多
The generation of high-quality 3D models from single 2D images remains challenging in terms of accuracy and completeness.Deep learning has emerged as a promising solution,offering new avenues for improvements.However,...The generation of high-quality 3D models from single 2D images remains challenging in terms of accuracy and completeness.Deep learning has emerged as a promising solution,offering new avenues for improvements.However,building models from scratch is computationally expensive and requires large datasets.This paper presents a transfer-learning-based approach for category-specific 3D reconstruction from a single 2D image.The core idea is to fine-tune a pre-trained model on specific object categories using new,unseen data,resulting in specialized versions of the model that are better adapted to reconstruct particular objects.The proposed approach utilizes a three-phase pipeline comprising image acquisition,3D reconstruction,and refinement.After ensuring the quality of the input image,a ResNet50 model is used for object recognition,directing the image to the corresponding category-specific model to generate a voxel-based representation.The voxel-based 3D model is then refined by transforming it into a detailed triangular mesh representation using the Marching Cubes algorithm and Laplacian smoothing.An experimental study,using the Pix2Vox model and the Pascal3D dataset,has been conducted to evaluate and validate the effectiveness of the proposed approach.Results demonstrate that category-specific fine-tuning of Pix2Vox significantly outperforms both the original model and the general model fine-tuned for all object categories,with substantial gains in Intersection over Union(IoU)scores.Visual assessments confirm improvements in geometric detail and surface realism.These findings indicate that combining transfer learning with category-specific fine tuning and refinement strategy of our approach leads to better-quality 3D model generation.展开更多
Objective:To evaluate the hepatoprotective effects of skate-derived bioactives-collagen peptides(CPs)and chondroitin-against ethanol(EtOH)-induced liver injury and to elucidate their underlying mechanisms.Methods:The ...Objective:To evaluate the hepatoprotective effects of skate-derived bioactives-collagen peptides(CPs)and chondroitin-against ethanol(EtOH)-induced liver injury and to elucidate their underlying mechanisms.Methods:The protective effects of CPs and chondroitin were assessed in different in vitro and in vivo EtOH-induced injury models.Oxidative stress was evaluated by measuring reactive oxygen species production and antioxidant markers(NRF2 and GCLC).EtOH metabolism was examined by measuring alchohol-metabolizing enzymes(alcohol dehydrogenase and aldehyde dehydrogenase)and cytochrome P450 enzymes.Furthermore,lipid dysregulation was assessed by Oil Red O staining and determination of lipogenic markers(SREBP-1 and FAS).Liver injury was also evaluated by measuring serum glutamate oxaloacetate transaminase and glutamate pyruvate transaminase,and performing histological analysis.Results:In hepatocytes and zebrafish,both CPs and chondroitin reduced oxidative stress,downregulated cytochrome P450 enzymes and lipogenic markers,and enhanced antioxidant defenses,with chondroitin showing the strongest hepatoprotection.In EtOH-fed mice,chondroitin significantly improved liver enzyme profiles,reduced hepatic lipid accumulation and inflammation,and restored antioxidant and metabolic homeostasis.Conclusions:Skate-derived chondroitin significantly attenuates EtOH-induced liver injury by modulating oxidative stress,EtOH metabolism,and lipid regulation.These findings demonstrate the hepatoprotective potential of chondroitin in different preclinical models of alcohol-induced liver damage.展开更多
Localized high-concentration electrolytes(LHCEs)are considered as promising electrolyte candidates to resolve technical issues of metal batteries owing to their unique interfacial properties and solvation structures.H...Localized high-concentration electrolytes(LHCEs)are considered as promising electrolyte candidates to resolve technical issues of metal batteries owing to their unique interfacial properties and solvation structures.Herein,we propose a self-assembly chemical strategy into the LCHEs induced by ordered nanostructure of zwitterionic co-solutes for highly efficient and ultrastable zinc(Zn)metal batteries.Through the systematic screening of six zwitterionic compounds,3-(decyldimethylammonio)propanesulfonate salt(C_(10))with the decyl chain and zwitterions was determined as an optimum to construct quasi-spherical aggregates with a periodic length of 3.77 nm,as confirmed by comprehensive synchronous small-angle X-ray scattering,Guinier,pair distance distribution function,Porod,and other spectroscopic characterizations and molecular dynamic simulation.In particularly,this self-assembled structure in electrolyte environments was attributed to increasing the proportion of both contact and aggregated ion pairs for the formation of LHCEs as well as to providing fast and selective Zn^(2+)conducting channels and uniform solid electrolyte interfaces for facilitated charge transfer kinetics.Moreover,the preferential adsorption of the self-assembled C_(10)on the Zn(002)surface modulated the electrical double layer to suppress hydrogen evolution and corrosion reactions.Consequently,the Zn‖Zn symmetric cells in Zn(OTf)_(2)/C_(10)electrolytes showed long-term plating/stripping behaviors over 2800 h at 1 mA cm^(-2)and 1 mAh cm^(-2)as well as over 1200 h even at 5 mA cm^(-2)and 5 mAh cm^(-2)with a very high depth of discharge of 42.7%.Furthermore,the ZnllVO_(2)/CNT full cells in Zn(OTf)_(2)/C_(10)electrolytes delivered a record-high capacity of 8.10 mAh cm^(-2)at an ultrahigh cathode mass loading of 50 mg cm^(-2)after 150 cycles.展开更多
Dual-polarization(dual-pol)radar can measure additional parameters that provide more microphysical information of precipitation systems than those provided by conventional Doppler radar.The dual-pol parameters have be...Dual-polarization(dual-pol)radar can measure additional parameters that provide more microphysical information of precipitation systems than those provided by conventional Doppler radar.The dual-pol parameters have been successfully utilized to investigate precipitation microphysics and improve radar quantitative precipitation estimation(QPE).The recent progress in dual-pol radar research and applications in China is summarized in four aspects.Firstly,the characteristics of several representative dual-pol radars are reviewed.Various approaches have been developed for radar data quality control,including calibration,attenuation correction,calculation of specific differential phase shift,and identification and removal of non-meteorological echoes.Using dual-pol radar measurements,the microphysical characteristics derived from raindrop size distribution retrieval,hydrometeor classification,and QPE is better understood in China.The limited number of studies in China that have sought to use dual-pol radar data to validate the microphysical parameterization and initialization of numerical models and assimilate dual-pol data into numerical models are summarized.The challenges of applying dual-pol data in numerical models and emerging technologies that may make significant impacts on the field of radar meteorology are discussed.展开更多
MXenes are emerging transition metal carbides and nitrides-based 2D conductive materials.They have found wide applications in sensors due to their excellent valuable properties.This paper reviews the recent research s...MXenes are emerging transition metal carbides and nitrides-based 2D conductive materials.They have found wide applications in sensors due to their excellent valuable properties.This paper reviews the recent research status of MXene-based electrochemical(bio)sensors for detecting biomarkers,pesticides,and other aspects.The first part of this paper introduced the synthesis strategy and the effect of surface modification on various prop-erties of MXenes.The second part of this paper discussed the application of MXenes as electrode modifiers for detecting pesticides,environmental pollutants,and biomarkers such as glucose,hydrogen peroxide,etc.Hope this review will inspire more efforts toward research on MXene-based sensors to meet the growing requirements.展开更多
From July to September 2008, air samples were collected aboard the R/V XUE LONG icebreaker （Snow Dragon） as part of the 2008 Chinese National Arctic Research Expedition program. ∑20PCBs in the atmosphere ranged fro...From July to September 2008, air samples were collected aboard the R/V XUE LONG icebreaker （Snow Dragon） as part of the 2008 Chinese National Arctic Research Expedition program. ∑20PCBs in the atmosphere ranged from 6.20 to 365 pg.m^-3 with average concentration 117±107 pg.m^- 3. Congener profiles in all samples showed a prevalence of tri- and tetrachlorobiphenyls, dominated by PCB-18, PCB-28, PCB-44 and PCB-52. Along the cruise, the highest concentration was observed over the Sea of Japan and the lowest over the high-latitude Arctic Ocean. Air mass backward trajectories indicated that samples with relatively high levels of PCBs might have been influenced by atmospheric transport of these chemicals from primary and/ or secondary sources. PCB-18 displayed a significant correlation between vapor pressure and ambient temperature along the cruise, but there was no such correlation between gas-phase concentration and latitude. This suggests that atmospheric PCB-18 was related to volatilization from the earth surface during summer 2008, during which temperatures were relatively high. PCB-52 presented a significant correlation between gas-phase concentration and latitude, but no such correlation was found between vapor pressure and ambient temperature, indicating that atmospheric PCB-52 detected during the cruise might be attributed directly to atmospheric transport from source regions. In the Arctic, levels of PCB-52 in the floating sea ice region were higher than those measured in the open sea area and pack ice region. Intense ice retreat during summer 2008 might have enhanced the volatilization of previously accumulated PCBs from sea ice, especially those with heavier molecular weight and lower vapor pressure such as PCB-52.展开更多
The generation of runaway electrons(REs)is observed during the low-density helium ohmic plasma discharge in the Experimental Advanced Superconducting Tokamak(EAST).The growth rate of hard x-ray(HXR)is inversely propor...The generation of runaway electrons(REs)is observed during the low-density helium ohmic plasma discharge in the Experimental Advanced Superconducting Tokamak(EAST).The growth rate of hard x-ray(HXR)is inversely proportional to the line-average density.Besides,the RE generation in helium plasma is higher than that in deuterium plasma at the same density,which is obtained by comparing the growth rate of HXR with the same discharge conditions.The potential reason is the higher electron temperature of helium plasma in the same current and electron density plateau.Furthermore,two Alfvén eigenmodes driven by REs have been observed.The frequency evolution of the mode is not fully satisfied with the Alfvén scaling and when extension of the Alfvén frequency is towards 0,the high frequency branch is~50 kHz.The different spatial position of the two modes and the evolution of the helium concentration could be used to understand deviation between theoretical and experimental observation.展开更多
The extraordinary strength of metal/graphene composites is significantly determined by the characteristic size,distribution and morphology of graphene.However,the effect of the graphene size/distribution on the mechan...The extraordinary strength of metal/graphene composites is significantly determined by the characteristic size,distribution and morphology of graphene.However,the effect of the graphene size/distribution on the mechanical properties and related strengthening mechanisms has not been fully elucidated.Herein,under the same volume fraction and distribution conditions of graphene,molecular dynamics simulations were used to investigate the effect of graphene sheet size on the hardness and deformation behavior of Cu/graphene composites under complex stress field.Two models of pure single crystalline Cu and graphene fully covered Cu matrix composite were constructed for comparison.The results show that the strengthening effect changes with varying the graphene sheet size.Besides the graphene dislocation blocking effect and the load-bearing effect,the deformation mechanisms change from stacking fault tetrahedron,dislocation bypassing and dislocation cutting to dislocation nucleation in turn with decreasing the graphene sheet size.The hardness of Cu/graphene composite,with the graphene sheet not completely covering the metal matrix,can even be higher than that of the fully covered composite.The extra strengthening mechanisms of dislocation bypassing mechanism and the stacking fault tetrahedra pinning dislocation mechanism contribute to the increase in hardness.展开更多
The eutectic point is a critical parameter in the phase diagrams of solid–liquid equilibrium. In this study, high-pressure differential thermal analysis(HPDTA) was utilized to measure the melting temperatures of Fe–...The eutectic point is a critical parameter in the phase diagrams of solid–liquid equilibrium. In this study, high-pressure differential thermal analysis(HPDTA) was utilized to measure the melting temperatures of Fe–C alloy(3.4–4.2 wt.% C)under 5 GPa and to plot the liquidus temperature curves spanning from hypoeutectic to hypereutectic compositions. Our results indicate that under 5 GPa, the carbon content at the eutectic point of the Fe–C alloy decreases to 3.6–3.7 wt.%C, representing a reduction of approximately 0.6 wt.% C compared to the atmospheric pressure value(4.3 wt.% C). Concurrently, the eutectic temperature rises to 1195℃, showing an elevation of 48℃relative to the atmospheric pressure condition(1147℃). Microstructural analysis, x-ray diffraction(XRD), and hardness tests further corroborate these findings, demonstrating that high pressure significantly suppresses the solubility of carbon in γ-Fe, resulting in a decrease in the eutectic carbon content. Additionally, the hardness of the Fe–C alloy under 5 GPa is increased by more than 50% compared to that of the same type of Fe–C alloy under atmospheric pressure. This study provides essential experimental data for constructing high-pressure Fe–C phase diagrams and offers valuable insights for the design of high-performance Fe-based materials under extreme conditions.展开更多
Surfactants play a critical role in enhanced oil recovery(EOR) applications;however,their performance is often compromised in harsh reservoir conditions,such as high temperature and high salinity,due to precipitation ...Surfactants play a critical role in enhanced oil recovery(EOR) applications;however,their performance is often compromised in harsh reservoir conditions,such as high temperature and high salinity,due to precipitation caused by interactions with multivalent metal ions.Chelating agents were introduced into oilfields for various purposes due to their ability to sequester metal ions.In this work,we conducted a comprehensive investigation about chelating agent-surfactant(CS) flooding for carbonate reservoirs,as an alternative to the well-established alkaline surfactant(AS) flooding used in sandstone.The tested surfactants include sodium dodecyl sulfate(anionic)(SDS),dodecyltrimethylammonium bromide(cationic)(DTAB),Triton X100(nonionic),and a locally synthesized zwitterionic surfactant.The tested chelating agents include diethylenetriaminepentaacetic acid(DTPA),ethylenediaminetetraacetic acid,and glutamic acid N,N-diacetic acid.pH and temperature,as dominant factors in chelating agent solubility and brine stability,were modified to test chelating agent solutions of different concentrations and their mixtures with surfactants.Interfacial tension reduction by chelating agents alone,surfactants alone,and their mixtures were measured.Wettability alteration brought by chelating agents and surfactants on carbonate rock surfaces was evaluated using the static contact angle method.Based on the obtained results,chelating agents can be applied as low-cost additives for surfactant stabilization in high salinity conditions.The addition of chelating agents significantly improved the stability of SDS and DTAB in salt solutions and seawater.At a relatively low concentration(0.25 wt%),DTPA was able to stabilize DTAB of 1.00 wt% in seawater at high temperature(90℃).DTPA,among the tested three chelating agents,exhibited a stronger stabilization effect on surfactants of different ion types.When chelating agents are to be applied in brine,an optimal applicable pH range of 5-9 is recommended so not to induce solubility issue of chelating agents or stability issues of metal ions.In this range,IFT reduction is more significant at high pH,while wettability alteration is more significant at low pH.The combination of a cationic surfactant with a chelating agent forms a low adsorption wettability modifier which can change strongly oil-wet rock to water-wet conditions,thus significantly increasing the residual oil recovery from oil-wet carbonate formations.Zwitterionic and nonionic surfactants are also applicable to combine with a chelating agent for EOR purposes.Anionic surfactant SDS,however,showed a growing inhibition on the wettability alteration effect induced by EDTA as the concentration of SDS increased.展开更多
The effects of Yb/Zr micro-alloying on the microstructure,mechanical properties,and corrosion resistance of an Al-Zn-Mg-Cu alloy were systematically investigated.Upon the addition of Yb/Zr to the Al-Zn-Mg-Cu alloy,the...The effects of Yb/Zr micro-alloying on the microstructure,mechanical properties,and corrosion resistance of an Al-Zn-Mg-Cu alloy were systematically investigated.Upon the addition of Yb/Zr to the Al-Zn-Mg-Cu alloy,the grain boundaries were pinned by high-density nanosized Al_(3)(Yb,Zr)precipitates during extrusion deformation,consequently,the average grain size was significantly reduced from 232.7μm to 3.2μm.This grain refinement contributed substantially to the improvement in both strength and elongation.The ultimate tensile strength,yield strength,and elongation of the Yb/Zr modified alloy increased to 705.3 MPa,677.6 MPa,and 8.7%,respectively,representing enhancements of 16.2%,19.3%,and 112.2%compared to the unmodified alloy.Moreover,the distribution of MgZn_(2)phases along grain boundaries became more discontinuous in the Yb/Zr modified alloy,which effectively retarded the propagation of intergranular corrosion and improved the corrosion resistance.展开更多
Solid polymer electrolytes have garnered significant attention for lithium batteries because of their flexibility and safety.However,poor ionic conductivity,lithium dendrite formation,and high impedance hinder their p...Solid polymer electrolytes have garnered significant attention for lithium batteries because of their flexibility and safety.However,poor ionic conductivity,lithium dendrite formation,and high impedance hinder their practical application.In this study,a thin,flexible,3D hybrid solid electrolyte(3DHSE)is prepared by in situ thermal cross-linking polymerization with electrospun 3D nanowebs.The 3DHSE comprises Al-doped Li_(7)La_(3)Zr_(2)O_(12)(ALLZO)embedded in electrospun poly(vinylidene fluoride-cohexafluoropropylene)(PVDF-HFP)nonwoven 3D nanowebs and an in situ cross-linked polyethylene oxide(PEO)-based solid polymer electrolyte.The 3DHSE exhibits high tensile strength(6.55 MPa),a strain of 40.28%,enhanced ionic conductivity(7.86×10^(-4) S cm^(-1)),and a superior lithium-ion transference number(0.76)to that of the PVDF-HFP-based solid polymer electrolyte(PSPE).This enables highly stable lithium plating/stripping cycling for over 900 h at 25℃ with a current density of 0.2 mA cm^(-2).The LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NCM811)/3DHSE/Li cell has a higher capacity(140.56 mAh g^(-1) at 0.1 C)than the NCM811/PSPE/Li cell(124.88 mAh g^(-1) at 0.1 C)at 25℃.The 3DHSE enhances mechanical properties,stabilizes interfacial contact,improves ion transport,prevents NCM811 cracking,and significantly boosts cycling performance.This study highlights the potential of the 3DHSE as a candidate for advanced lithium polymer battery technology.展开更多
This study investigated the effects of interstitial carbon doping on the microstructural and magnetocaloric properties of off-stoichiometric La_(1.2)Fe_(11.6)Si_(1.4)Cx(x=0,0.25,0.5,0.75,1)alloys.The alloys were prepa...This study investigated the effects of interstitial carbon doping on the microstructural and magnetocaloric properties of off-stoichiometric La_(1.2)Fe_(11.6)Si_(1.4)Cx(x=0,0.25,0.5,0.75,1)alloys.The alloys were prepared by melt-spinning following vacuum arc-melting.For the as-prepared and annealed samples,the carbon existed in the La_(2)Fe_(2)Si_(2)C and NaZn_(13)-type La(Fe,Si)_(13)(denoted by 1:13)phases,respectively.During the annealing process,the C atoms inhibited the diffusion reaction and depressed the generation of 1:13 phase,reducing mass fraction of the 1:13 phase in annealed La_(1.2)Fe_(11.6)Si_(1.4)Cx compounds.The introduction of carbon resulted in lattice expansion and increased the Curie temperature(T_(C))from 192 K to 273 K with x=0.5.The first-order magnetic transition was gradually transformed into the second-order magnetic transition with increasing carbon content,which induced the significant reduction of thermal and magnetic hysteresis,as well as the maximum magnetic entropy change and adiabatic temperature change vary from 18.92 J/(kg·K)to 4.60 J/(kg·K)and from 4.9 K to 2.2 K under an applied field change of 0-2 T.The results demonstrate that interstitial carbon doping is an effective strategy to improve the magnetocaloric performance of La(Fe,Si)_(13)alloys.展开更多
Lithium metal is a highly promising anode for next-generation rechargeable batteries due to its ultrahigh theoretical capacity(3860 mAh g^(-1))and the lowest electrochemical potential(-3.04 V vs.SHE).However,its pract...Lithium metal is a highly promising anode for next-generation rechargeable batteries due to its ultrahigh theoretical capacity(3860 mAh g^(-1))and the lowest electrochemical potential(-3.04 V vs.SHE).However,its practical application is hindered by dendritic growth,unstable solid electrolyte interphase(SEI),and electrically isolated"dead"lithium,which degrade cycling performance and safety.To mitigate these issues by lowering the local current density,three-dimensional(3D)porous scaffolds have been explored,yet their effectiveness remains limited due to the intrinsically lithiophobic nature of scaffold surfaces.Here,we present a facile and scalable strategy to construct 3D nickel scaffolds(NiOSc-400)with an oxygen-rich,lithiophilic NiO interface,using a two-step tunable surface modification route.NiOSc-400promotes uniform Li^(+)adsorption and nucleation,while facilitating the in-situ formation of a Li_(2)O-based quasi-SEI via a conversion reaction.NiOSc-400 exhibits excellent cycling stability with a Coulombic efficiency of 99.9%over 800 cycles at 0.5 mA cm^(-2)and maintains a low overpotential of 28.9 mV at 15 mA cm^(-2).This work provides a practically viable platform for dendrite-free,high-performance lithium metal anodes by rationally engineering interfacial chemistry and scaffold architecture.展开更多
基金Deanship of Research and Graduate Studies at King Khalid University for funding this work through the Large Research Project(Grant No.RGP2/587/46).
文摘Photovoltaic(PV)systems in the field operate under complex,uncertain conditions rapid irradiance ramps,partial shading,temperature swings,surface soiling,and weak-grid disturbances including off-nominal frequency and voltage distortion that degrade energy yield and power quality.We propose a drift-aware,power-quality-constrained MPPT framework that co-optimizes MPPT,PLL,and current-loop gains under stochastic frequency drift,while enforcing IEEE-519 limits(per-order Ih/IL and TDD)during optimization.Unlike energy-only or THD-only methods,the design target integrates PQ constraints into the objective and is validated across calibrated drift scenarios with explicit per-order and TDD reporting.Operating scenarios are calibrated to Cameroon’s Southern Interconnected Grid and city-specific profiles(Douala/Yaoundé),combining measured-style irradiance/temperature traces,partial-shading patterns,and stochastic frequency drift up to±0.8 Hz with synthetic contingencies.Across a 30-scenario campaign,the proposed controller achievesηMPPT=99.3%–99.6%(vs.98.6%Incremental Conductance and 97.8%Perturb-and-Observe),lowers DC-link ripple by 35%–48%,reduces oscillatory PCC power by≈41%,maintains THD≤2.5%(5%limit)and PF≥0.99,and shortens irradiance-step settling from 85–110 ms to 50–65 ms.Sensitivity to PLL bandwidth shows a broad optimum(≈60–90 Hz)with minimum THD/ripple,and ablations confirm that explicit drift weighting is pivotal to ripple and THD suppression without sacrificing yield.The approach is controller-agnostic,firmware-deployable,and generalizes to other converter-interfaced renewables;we outline a short hardware-/HIL-validation path for adoption in Sub-Saharan grids.
基金supported by the National Natural Science Foundation of China(52071083,52231007,12327804,52471224)Zhuhai Fudan Innovation Institute,and the Science and Technology Commission of Shanghai Municipality(23ZR1405000).
文摘By the random distribution of metals in a single phase,entropy engineering is applied to construct dense neighboring active centers with diverse electronic and geometric structures,realizing the continuous optimization of multiple primary reactions for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).Many catalysts developed through entropy engineering have been built in nearly equimolar ratios to pursue high entropy,hindering the identification of the active sites and potentially diluting the concentration of real active sites while weakening their electronic interactions with reaction intermediates.Herein,this work proposes an entropy-engineering strategy in metal nanoparticle-embedded nitrogen carbon electrocatalysts,implemented by entropy-engineered Prussian blue analogs(PBA)as precursors to enhance the catalytic activity of primary Cu-Fe active sites.Through the introduction of the micro-strains driven by entropy engineering,density functional theory(DFT)calculations and geometric phase analysis(GPA)using Lorentz electron microscopy further elucidate the optimization of the adsorption/desorption of intermediates.Furthermore,the multi-dimensional morphology and the size diminishment of the nanocrystals serve to expand the electrochemical area,maximizing the catalytic activity for both ORR and OER.Notably,the Zn-air battery assembled with CuFeCoNiZn-NC operated for over 1300 h with negligible decay.This work presents a paradigm for the design of low-cost electrocatalysts with entropy engineering for multi-step reactions.
文摘Hydraulic fracturing is a commonly used stimulation technique for production optimization in various geological formations such as tight sandstone,shale,coal bed methane,and heat extraction in geothermal reservoirs.Breakdown pressure is a vital component in hydraulic fracture job design,which is affected by various parameters including rock strength and depth.Various methods including modelling and experimental approaches exist to quantify the breakdown pressure.There have been many strategies to reduce this pressure for efficient and economical hydraulic fracture jobs,especially when this pressure exceeds pump capacity.This study provides a detailed review of breakdown pressure in terms of fundamentals,influencing factors,and estimation approaches.In addition,different strategies are also presented to reduce the breakdown pressure along with cost analysis.Lastly,research gaps pertinent to this area are highlighted for emphasis in future research.Specifically,it has been found that high breakdown pressure is associated with challenges,but there are no comprehensive techniques and strategies to lower this pressure in formations with very high in situ stress profiles or complicated tectonic settings.Developing such methods is important to minimize operational failures,lower costs and reduce the environmental risks during reservoir exploitation.This study reviews the fundamentals,influencing factors,and estimation methods of breakdown pressure and provides a deep understanding of the strategies for its reduction.The study also presents the cost analyses,and highlights research gaps for future investigation.
基金Project supported by the Natural Science Foundation of Anhui Provincial Education Department(Grant No.KJ2019A0054)。
文摘NaNbO_(3)-based lead-free dielectric ceramics possess significant application prospects in the field of dielectric capacitors.However,their development is hindered by low recoverable energy storage density(W_(rec))and energy storage efficiency(η).Herein,novel NaNbO_(3)-based ceramics,(1-x)[0.7Na_(0.97)Sm_(0.01)NbO_(3)–0.3(Sr_(0.7)Bi_(0.2))(Ti_(0.8)Zr_(0.2))O_(3)]–xCaTiO_(3),were created by adding CaTiO_(3) linear dielectric,aiming to improve their energy storage performance(ESP).The phase structure,microstructure,dielectric properties,energy storage and charge–discharge performances of the ceramics were methodically analyzed.All components of the ceramics exhibit a perovskite structure consisting of two phases:antiferroelectric P-phase(AFE P)and antiferroelectric R-phase(AFE R),with the AFE R phase increasing as x rises.All ceramic surfaces exhibit clear grain morphology.The resultant ceramics have an appropriate dielectric constant and a small dielectric loss,which are beneficial for improving breakdown field strength(E_(b)).Finally,at an E_(b) of 470 kV/cm,0.85[0.7Na_(0.97)Sm_(0.01)NbO_(3)–0.3(Sr_(0.7)Bi_(0.2))(Ti_(0.8)Zr_(0.2))O_(3)]–0.15CaTiO_(3) ceramic achieves optimal ESP:W_(rec)=3.9 J/cm^(3),η=72.49%.In addition,it has remarkable stability with temperature and frequency in energy storage and displays ultrafast speed in the charge–discharge process(t_(0.9)=27 ns).
基金financial support from the Helmholtz Association and the German Federal Ministry of Education and Research(BMBF)within the ExcellBattUlm project(03XP0257D)the HighSafe-3 project(03XP0568A)。
文摘Energy density and safety are two crucial parameters when evaluating lithium-metal batteries(LMBs).Herein,we present an ultralight polymer-based current collector,incorporating flame-retardant materials,designed specifically for thin lithium-metal anodes.Compared to the traditional copper current collector(8.96 mg cm^(-2),10μm thick),the polymer-based current collector(12μm thick)has a significantly lower areal density of 1.41 mg cm^(-2),i.e.,only one-sixth of the copper collector,thus enabling substantially higher energy densities.Accordingly,when employed in Li||NMC_(622)full-cells,the polymer-based current collector enables a specific energy of 449 Wh kg^(-1),representing a notable improvement of about14.5%compared to cells employing a classic copper current collector.The inclusion of Al(OH)_(3) as a flame retardant into the current collector suppresses flammability and,thereby,significantly improves the safety of the resulting LMBs.
基金funded by the Research,Development,and Innovation Authority(RDIA)—Kingdom of Saudi Arabia—under supervision Energy,Industry,and Advanced Technologies Research Center,Taibah University,Madinah,Saudi Arabia with grant number(12979-iau-2023-TAU-R-3-1-EI-).
文摘The generation of high-quality 3D models from single 2D images remains challenging in terms of accuracy and completeness.Deep learning has emerged as a promising solution,offering new avenues for improvements.However,building models from scratch is computationally expensive and requires large datasets.This paper presents a transfer-learning-based approach for category-specific 3D reconstruction from a single 2D image.The core idea is to fine-tune a pre-trained model on specific object categories using new,unseen data,resulting in specialized versions of the model that are better adapted to reconstruct particular objects.The proposed approach utilizes a three-phase pipeline comprising image acquisition,3D reconstruction,and refinement.After ensuring the quality of the input image,a ResNet50 model is used for object recognition,directing the image to the corresponding category-specific model to generate a voxel-based representation.The voxel-based 3D model is then refined by transforming it into a detailed triangular mesh representation using the Marching Cubes algorithm and Laplacian smoothing.An experimental study,using the Pix2Vox model and the Pascal3D dataset,has been conducted to evaluate and validate the effectiveness of the proposed approach.Results demonstrate that category-specific fine-tuning of Pix2Vox significantly outperforms both the original model and the general model fine-tuned for all object categories,with substantial gains in Intersection over Union(IoU)scores.Visual assessments confirm improvements in geometric detail and surface realism.These findings indicate that combining transfer learning with category-specific fine tuning and refinement strategy of our approach leads to better-quality 3D model generation.
基金supported by the National Research Foundation of Korea grant funded by the Korean government(Grant no.:RS-2022-NR070862).
文摘Objective:To evaluate the hepatoprotective effects of skate-derived bioactives-collagen peptides(CPs)and chondroitin-against ethanol(EtOH)-induced liver injury and to elucidate their underlying mechanisms.Methods:The protective effects of CPs and chondroitin were assessed in different in vitro and in vivo EtOH-induced injury models.Oxidative stress was evaluated by measuring reactive oxygen species production and antioxidant markers(NRF2 and GCLC).EtOH metabolism was examined by measuring alchohol-metabolizing enzymes(alcohol dehydrogenase and aldehyde dehydrogenase)and cytochrome P450 enzymes.Furthermore,lipid dysregulation was assessed by Oil Red O staining and determination of lipogenic markers(SREBP-1 and FAS).Liver injury was also evaluated by measuring serum glutamate oxaloacetate transaminase and glutamate pyruvate transaminase,and performing histological analysis.Results:In hepatocytes and zebrafish,both CPs and chondroitin reduced oxidative stress,downregulated cytochrome P450 enzymes and lipogenic markers,and enhanced antioxidant defenses,with chondroitin showing the strongest hepatoprotection.In EtOH-fed mice,chondroitin significantly improved liver enzyme profiles,reduced hepatic lipid accumulation and inflammation,and restored antioxidant and metabolic homeostasis.Conclusions:Skate-derived chondroitin significantly attenuates EtOH-induced liver injury by modulating oxidative stress,EtOH metabolism,and lipid regulation.These findings demonstrate the hepatoprotective potential of chondroitin in different preclinical models of alcohol-induced liver damage.
基金financially supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(No.NRF-2020R1A3B2079803 and No.RS-2024-00453815),Republic of Korea。
文摘Localized high-concentration electrolytes(LHCEs)are considered as promising electrolyte candidates to resolve technical issues of metal batteries owing to their unique interfacial properties and solvation structures.Herein,we propose a self-assembly chemical strategy into the LCHEs induced by ordered nanostructure of zwitterionic co-solutes for highly efficient and ultrastable zinc(Zn)metal batteries.Through the systematic screening of six zwitterionic compounds,3-(decyldimethylammonio)propanesulfonate salt(C_(10))with the decyl chain and zwitterions was determined as an optimum to construct quasi-spherical aggregates with a periodic length of 3.77 nm,as confirmed by comprehensive synchronous small-angle X-ray scattering,Guinier,pair distance distribution function,Porod,and other spectroscopic characterizations and molecular dynamic simulation.In particularly,this self-assembled structure in electrolyte environments was attributed to increasing the proportion of both contact and aggregated ion pairs for the formation of LHCEs as well as to providing fast and selective Zn^(2+)conducting channels and uniform solid electrolyte interfaces for facilitated charge transfer kinetics.Moreover,the preferential adsorption of the self-assembled C_(10)on the Zn(002)surface modulated the electrical double layer to suppress hydrogen evolution and corrosion reactions.Consequently,the Zn‖Zn symmetric cells in Zn(OTf)_(2)/C_(10)electrolytes showed long-term plating/stripping behaviors over 2800 h at 1 mA cm^(-2)and 1 mAh cm^(-2)as well as over 1200 h even at 5 mA cm^(-2)and 5 mAh cm^(-2)with a very high depth of discharge of 42.7%.Furthermore,the ZnllVO_(2)/CNT full cells in Zn(OTf)_(2)/C_(10)electrolytes delivered a record-high capacity of 8.10 mAh cm^(-2)at an ultrahigh cathode mass loading of 50 mg cm^(-2)after 150 cycles.
基金primarily supported by the National Key Research and Development Program of China(Grant Nos.2017YFC1501703 and 2018YFC1506404)the National Natural Science Foundation of China(Grant Nos.41875053,41475015 and 41322032)+2 种基金the National Fundamental Research 973 Program of China(Grant Nos.2013CB430101 and2015CB452800)the Open Research Program of the State Key Laboratory of Severe Weatherthe Key Research Development Program of Jiangsu Science and Technology Department(Social Development Program,No.BE2016732)
文摘Dual-polarization(dual-pol)radar can measure additional parameters that provide more microphysical information of precipitation systems than those provided by conventional Doppler radar.The dual-pol parameters have been successfully utilized to investigate precipitation microphysics and improve radar quantitative precipitation estimation(QPE).The recent progress in dual-pol radar research and applications in China is summarized in four aspects.Firstly,the characteristics of several representative dual-pol radars are reviewed.Various approaches have been developed for radar data quality control,including calibration,attenuation correction,calculation of specific differential phase shift,and identification and removal of non-meteorological echoes.Using dual-pol radar measurements,the microphysical characteristics derived from raindrop size distribution retrieval,hydrometeor classification,and QPE is better understood in China.The limited number of studies in China that have sought to use dual-pol radar data to validate the microphysical parameterization and initialization of numerical models and assimilate dual-pol data into numerical models are summarized.The challenges of applying dual-pol data in numerical models and emerging technologies that may make significant impacts on the field of radar meteorology are discussed.
文摘MXenes are emerging transition metal carbides and nitrides-based 2D conductive materials.They have found wide applications in sensors due to their excellent valuable properties.This paper reviews the recent research status of MXene-based electrochemical(bio)sensors for detecting biomarkers,pesticides,and other aspects.The first part of this paper introduced the synthesis strategy and the effect of surface modification on various prop-erties of MXenes.The second part of this paper discussed the application of MXenes as electrode modifiers for detecting pesticides,environmental pollutants,and biomarkers such as glucose,hydrogen peroxide,etc.Hope this review will inspire more efforts toward research on MXene-based sensors to meet the growing requirements.
基金supported by grants from the National Natural Science Foundation of China (Grant nos. 41025020, 40776001, and 41203075)Chinese Academy of Sciences (Grant no. KZCX2-YWQN506)+2 种基金the Fundamental Research Funds for the Central Universitiesfunded by the Area of Excellence Scheme under the University Grants Committee of the Hong Kong Special Administrative Region, China (Grant no. Ao E/P-04/2004)a Hong Kong Research Grants Council (Grant no. City U 160610)
文摘From July to September 2008, air samples were collected aboard the R/V XUE LONG icebreaker （Snow Dragon） as part of the 2008 Chinese National Arctic Research Expedition program. ∑20PCBs in the atmosphere ranged from 6.20 to 365 pg.m^-3 with average concentration 117±107 pg.m^- 3. Congener profiles in all samples showed a prevalence of tri- and tetrachlorobiphenyls, dominated by PCB-18, PCB-28, PCB-44 and PCB-52. Along the cruise, the highest concentration was observed over the Sea of Japan and the lowest over the high-latitude Arctic Ocean. Air mass backward trajectories indicated that samples with relatively high levels of PCBs might have been influenced by atmospheric transport of these chemicals from primary and/ or secondary sources. PCB-18 displayed a significant correlation between vapor pressure and ambient temperature along the cruise, but there was no such correlation between gas-phase concentration and latitude. This suggests that atmospheric PCB-18 was related to volatilization from the earth surface during summer 2008, during which temperatures were relatively high. PCB-52 presented a significant correlation between gas-phase concentration and latitude, but no such correlation was found between vapor pressure and ambient temperature, indicating that atmospheric PCB-52 detected during the cruise might be attributed directly to atmospheric transport from source regions. In the Arctic, levels of PCB-52 in the floating sea ice region were higher than those measured in the open sea area and pack ice region. Intense ice retreat during summer 2008 might have enhanced the volatilization of previously accumulated PCBs from sea ice, especially those with heavier molecular weight and lower vapor pressure such as PCB-52.
基金Project supported by the National Key R&D Program of China(Grant Nos.2017YFE0301205 and 2022YFE03050003)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.Y2021116)+1 种基金the National Natural Science Foundation of China(Grant Nos.12005262,12105186,12175277,and 11975271)the Users of Excellence Program of Hefei Science Center CAS(Grant No.2021HSC-UE016).
文摘The generation of runaway electrons(REs)is observed during the low-density helium ohmic plasma discharge in the Experimental Advanced Superconducting Tokamak(EAST).The growth rate of hard x-ray(HXR)is inversely proportional to the line-average density.Besides,the RE generation in helium plasma is higher than that in deuterium plasma at the same density,which is obtained by comparing the growth rate of HXR with the same discharge conditions.The potential reason is the higher electron temperature of helium plasma in the same current and electron density plateau.Furthermore,two Alfvén eigenmodes driven by REs have been observed.The frequency evolution of the mode is not fully satisfied with the Alfvén scaling and when extension of the Alfvén frequency is towards 0,the high frequency branch is~50 kHz.The different spatial position of the two modes and the evolution of the helium concentration could be used to understand deviation between theoretical and experimental observation.
基金Foundation of Northwest Institute for Nonferrous Metal Research(ZZXJ2203)Capital Projects of Financial Department of Shaanxi Province(YK22C-12)+3 种基金Innovation Capability Support Plan in Shaanxi Province(2023KJXX-083)Key Research and Development Projects of Shaanxi Province(2024GXYBXM-351,2024GX-YBXM-356)National Natural Science Foundation of China(62204207,12204383)Xi'an Postdoctoral Innovation Base Funding Program。
文摘The extraordinary strength of metal/graphene composites is significantly determined by the characteristic size,distribution and morphology of graphene.However,the effect of the graphene size/distribution on the mechanical properties and related strengthening mechanisms has not been fully elucidated.Herein,under the same volume fraction and distribution conditions of graphene,molecular dynamics simulations were used to investigate the effect of graphene sheet size on the hardness and deformation behavior of Cu/graphene composites under complex stress field.Two models of pure single crystalline Cu and graphene fully covered Cu matrix composite were constructed for comparison.The results show that the strengthening effect changes with varying the graphene sheet size.Besides the graphene dislocation blocking effect and the load-bearing effect,the deformation mechanisms change from stacking fault tetrahedron,dislocation bypassing and dislocation cutting to dislocation nucleation in turn with decreasing the graphene sheet size.The hardness of Cu/graphene composite,with the graphene sheet not completely covering the metal matrix,can even be higher than that of the fully covered composite.The extra strengthening mechanisms of dislocation bypassing mechanism and the stacking fault tetrahedra pinning dislocation mechanism contribute to the increase in hardness.
基金Project supported by the National Key Research and Development Program of China (Grant No. 2023YFA1406200)。
文摘The eutectic point is a critical parameter in the phase diagrams of solid–liquid equilibrium. In this study, high-pressure differential thermal analysis(HPDTA) was utilized to measure the melting temperatures of Fe–C alloy(3.4–4.2 wt.% C)under 5 GPa and to plot the liquidus temperature curves spanning from hypoeutectic to hypereutectic compositions. Our results indicate that under 5 GPa, the carbon content at the eutectic point of the Fe–C alloy decreases to 3.6–3.7 wt.%C, representing a reduction of approximately 0.6 wt.% C compared to the atmospheric pressure value(4.3 wt.% C). Concurrently, the eutectic temperature rises to 1195℃, showing an elevation of 48℃relative to the atmospheric pressure condition(1147℃). Microstructural analysis, x-ray diffraction(XRD), and hardness tests further corroborate these findings, demonstrating that high pressure significantly suppresses the solubility of carbon in γ-Fe, resulting in a decrease in the eutectic carbon content. Additionally, the hardness of the Fe–C alloy under 5 GPa is increased by more than 50% compared to that of the same type of Fe–C alloy under atmospheric pressure. This study provides essential experimental data for constructing high-pressure Fe–C phase diagrams and offers valuable insights for the design of high-performance Fe-based materials under extreme conditions.
基金supported by the College of Petroleum Engineering&Geoscience (CPG) at King Fahd University of Petroleum and Minerals (KFUPM)。
文摘Surfactants play a critical role in enhanced oil recovery(EOR) applications;however,their performance is often compromised in harsh reservoir conditions,such as high temperature and high salinity,due to precipitation caused by interactions with multivalent metal ions.Chelating agents were introduced into oilfields for various purposes due to their ability to sequester metal ions.In this work,we conducted a comprehensive investigation about chelating agent-surfactant(CS) flooding for carbonate reservoirs,as an alternative to the well-established alkaline surfactant(AS) flooding used in sandstone.The tested surfactants include sodium dodecyl sulfate(anionic)(SDS),dodecyltrimethylammonium bromide(cationic)(DTAB),Triton X100(nonionic),and a locally synthesized zwitterionic surfactant.The tested chelating agents include diethylenetriaminepentaacetic acid(DTPA),ethylenediaminetetraacetic acid,and glutamic acid N,N-diacetic acid.pH and temperature,as dominant factors in chelating agent solubility and brine stability,were modified to test chelating agent solutions of different concentrations and their mixtures with surfactants.Interfacial tension reduction by chelating agents alone,surfactants alone,and their mixtures were measured.Wettability alteration brought by chelating agents and surfactants on carbonate rock surfaces was evaluated using the static contact angle method.Based on the obtained results,chelating agents can be applied as low-cost additives for surfactant stabilization in high salinity conditions.The addition of chelating agents significantly improved the stability of SDS and DTAB in salt solutions and seawater.At a relatively low concentration(0.25 wt%),DTPA was able to stabilize DTAB of 1.00 wt% in seawater at high temperature(90℃).DTPA,among the tested three chelating agents,exhibited a stronger stabilization effect on surfactants of different ion types.When chelating agents are to be applied in brine,an optimal applicable pH range of 5-9 is recommended so not to induce solubility issue of chelating agents or stability issues of metal ions.In this range,IFT reduction is more significant at high pH,while wettability alteration is more significant at low pH.The combination of a cationic surfactant with a chelating agent forms a low adsorption wettability modifier which can change strongly oil-wet rock to water-wet conditions,thus significantly increasing the residual oil recovery from oil-wet carbonate formations.Zwitterionic and nonionic surfactants are also applicable to combine with a chelating agent for EOR purposes.Anionic surfactant SDS,however,showed a growing inhibition on the wettability alteration effect induced by EDTA as the concentration of SDS increased.
基金Project(51501228)supported by the National Natural Science Foundation of ChinaProject(202109)supported by the Open Sharing Fund for the Large-scale Instruments and Equipments of Central South University,China。
文摘The effects of Yb/Zr micro-alloying on the microstructure,mechanical properties,and corrosion resistance of an Al-Zn-Mg-Cu alloy were systematically investigated.Upon the addition of Yb/Zr to the Al-Zn-Mg-Cu alloy,the grain boundaries were pinned by high-density nanosized Al_(3)(Yb,Zr)precipitates during extrusion deformation,consequently,the average grain size was significantly reduced from 232.7μm to 3.2μm.This grain refinement contributed substantially to the improvement in both strength and elongation.The ultimate tensile strength,yield strength,and elongation of the Yb/Zr modified alloy increased to 705.3 MPa,677.6 MPa,and 8.7%,respectively,representing enhancements of 16.2%,19.3%,and 112.2%compared to the unmodified alloy.Moreover,the distribution of MgZn_(2)phases along grain boundaries became more discontinuous in the Yb/Zr modified alloy,which effectively retarded the propagation of intergranular corrosion and improved the corrosion resistance.
基金supported by the National Research Foundation of Korea(NRF)(no.:NRF-2020M3H4A3081874)the National Research Council of Science&Technology(NST)grant by the Korea government(MSIT)(no.:GTL24011-000)the Korea Research Institute of Chemical Technology(KRICT),Republic of Korea(no.KS2422-20).
文摘Solid polymer electrolytes have garnered significant attention for lithium batteries because of their flexibility and safety.However,poor ionic conductivity,lithium dendrite formation,and high impedance hinder their practical application.In this study,a thin,flexible,3D hybrid solid electrolyte(3DHSE)is prepared by in situ thermal cross-linking polymerization with electrospun 3D nanowebs.The 3DHSE comprises Al-doped Li_(7)La_(3)Zr_(2)O_(12)(ALLZO)embedded in electrospun poly(vinylidene fluoride-cohexafluoropropylene)(PVDF-HFP)nonwoven 3D nanowebs and an in situ cross-linked polyethylene oxide(PEO)-based solid polymer electrolyte.The 3DHSE exhibits high tensile strength(6.55 MPa),a strain of 40.28%,enhanced ionic conductivity(7.86×10^(-4) S cm^(-1)),and a superior lithium-ion transference number(0.76)to that of the PVDF-HFP-based solid polymer electrolyte(PSPE).This enables highly stable lithium plating/stripping cycling for over 900 h at 25℃ with a current density of 0.2 mA cm^(-2).The LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NCM811)/3DHSE/Li cell has a higher capacity(140.56 mAh g^(-1) at 0.1 C)than the NCM811/PSPE/Li cell(124.88 mAh g^(-1) at 0.1 C)at 25℃.The 3DHSE enhances mechanical properties,stabilizes interfacial contact,improves ion transport,prevents NCM811 cracking,and significantly boosts cycling performance.This study highlights the potential of the 3DHSE as a candidate for advanced lithium polymer battery technology.
基金supported by the National Natural Science Foundation of China(Grant No.52272263)the University Synergy Innovation Program of Anhui Province,China(Grant No.GXXT-2022-008)+2 种基金the University Natural Science Research Project of Anhui Province,China(Grant No.2024AH050145)the Youth Foundation of Anhui University of Technology(Grant No.QZ202303)the National Innovation and Entrepreneurship Training Program for College Students(Grant No.202310360018).
文摘This study investigated the effects of interstitial carbon doping on the microstructural and magnetocaloric properties of off-stoichiometric La_(1.2)Fe_(11.6)Si_(1.4)Cx(x=0,0.25,0.5,0.75,1)alloys.The alloys were prepared by melt-spinning following vacuum arc-melting.For the as-prepared and annealed samples,the carbon existed in the La_(2)Fe_(2)Si_(2)C and NaZn_(13)-type La(Fe,Si)_(13)(denoted by 1:13)phases,respectively.During the annealing process,the C atoms inhibited the diffusion reaction and depressed the generation of 1:13 phase,reducing mass fraction of the 1:13 phase in annealed La_(1.2)Fe_(11.6)Si_(1.4)Cx compounds.The introduction of carbon resulted in lattice expansion and increased the Curie temperature(T_(C))from 192 K to 273 K with x=0.5.The first-order magnetic transition was gradually transformed into the second-order magnetic transition with increasing carbon content,which induced the significant reduction of thermal and magnetic hysteresis,as well as the maximum magnetic entropy change and adiabatic temperature change vary from 18.92 J/(kg·K)to 4.60 J/(kg·K)and from 4.9 K to 2.2 K under an applied field change of 0-2 T.The results demonstrate that interstitial carbon doping is an effective strategy to improve the magnetocaloric performance of La(Fe,Si)_(13)alloys.
基金supported by the research grant of the Gyeongsang National University in 2024supported by the National Research Foundation of Korea(NRF)grants funded by the Korean Government(NRF-2022R1C1C1011386)。
文摘Lithium metal is a highly promising anode for next-generation rechargeable batteries due to its ultrahigh theoretical capacity(3860 mAh g^(-1))and the lowest electrochemical potential(-3.04 V vs.SHE).However,its practical application is hindered by dendritic growth,unstable solid electrolyte interphase(SEI),and electrically isolated"dead"lithium,which degrade cycling performance and safety.To mitigate these issues by lowering the local current density,three-dimensional(3D)porous scaffolds have been explored,yet their effectiveness remains limited due to the intrinsically lithiophobic nature of scaffold surfaces.Here,we present a facile and scalable strategy to construct 3D nickel scaffolds(NiOSc-400)with an oxygen-rich,lithiophilic NiO interface,using a two-step tunable surface modification route.NiOSc-400promotes uniform Li^(+)adsorption and nucleation,while facilitating the in-situ formation of a Li_(2)O-based quasi-SEI via a conversion reaction.NiOSc-400 exhibits excellent cycling stability with a Coulombic efficiency of 99.9%over 800 cycles at 0.5 mA cm^(-2)and maintains a low overpotential of 28.9 mV at 15 mA cm^(-2).This work provides a practically viable platform for dendrite-free,high-performance lithium metal anodes by rationally engineering interfacial chemistry and scaffold architecture.
