Palladium-supported cobalt hydroxide(Co(OH)_(2)-Pd) nanoplates were fabricated in an aqueous solution and employed as a catalyst for the reduction of 4-nitrophenol.For the preparation of Co(OH)2-Pd,Pd nanoparticles we...Palladium-supported cobalt hydroxide(Co(OH)_(2)-Pd) nanoplates were fabricated in an aqueous solution and employed as a catalyst for the reduction of 4-nitrophenol.For the preparation of Co(OH)2-Pd,Pd nanoparticles were anchored on the Co(OH)_(2) nanoplates after the reduction of Na;PdCl;by ascorbic acid in the absence of a stabilizer at room temperature.The observations under transmission and scanning electron microscopy reveal that Pd nanoparticles with a size of 2-5 nm are uniformly dispersed on the surface of the Co(OH)_(2) nanoplates.In catalytic test,the conversion of 4-nitrophenol to 4-aminophenol is completed within 6 min in the presence of Co(OH)_(2)-Pd(1000) nanoplates with2.18 at.% Pd,and the corresponding kinetic constant is 0.0089 s;in the first test.The catalyst retains relatively high activity after several cycles.The results demonstrate that the Co(OH)_(2)-Pd(1000) nanoplates exhibit high catalytic activity toward the reduction of 4-nitrophenol in the presence of NaBH;.展开更多
Improving and optimizing the target properties of ceramics via the high entropy strategy has attracted significant attention.Rare earth niobate is a potential thermal barrier coating(TBCs)material,but its poor high-te...Improving and optimizing the target properties of ceramics via the high entropy strategy has attracted significant attention.Rare earth niobate is a potential thermal barrier coating(TBCs)material,but its poor high-temperature phase stability limits its further application.In this work,four sets of TBCs high-entropy ceramics,(Sm_(1/5)Dy_(1/5)Ho_(1/5)Er_(1/5)Yb_(1/5))(Nb_(1/2)Ta_(1/2))O_(4)(5NbTa),(Sm_(1/6)Dy_(1/6)Ho_(1/6)Er_(1/6)Yb_(1/6)Lu_(1/6))(Nb_(1/2)Ta_(1/2))O_(4)(6NbTa),(Sm_(1/7)Gd_(1/7)Dy_(1/7)Ho_(1/7)Er_(1/7)Yb_(1/7)Lu_(1/7))(Nb_(1/2)Ta_(1/2))O_(4)(7NbTa),(Sm_(1/8)Gd_(1/8)Dy_(1/8)Ho_(1/8)Er_(1/8)Tm_(1/8)Yb_(1/8)Lu_(1/8))(Nb_(1/2)Ta_(1/2))O_(4)(8NbTa)are synthesized using a solid-state reaction method at 1650℃for 6 h.Firstly,the X-ray diffractometer(XRD)patterns display that the samples are all single-phase solid solution structures(space group C 2/c).Differential scanning calorimetry(DSC)and the high-temperature XRD of 8NbTa cross-check that the addition of Ta element in 8HERN increases the phase transition temperature above 1400℃,which can be attributed to that the Ta/Nb co-doping at B site introduces the fluctuation of the bond strength of Ta-O and Nb-O.Secondly,compared to high-entropy rare-earth niobates,the introduction of Ta atoms at B site substantially reduce thermal conductivity(re-duced by 44%,800℃)with the seven components high entropy ceramic as an example.The low thermal conductivity means strong phonon scattering,which may originate from the softening acoustic mode and flattened phonon dispersion in 5–8 principal element high entropy rare earth niobium tantalates(5–8NbTa)revealed by the first-principles calculations.Thirdly,the Ta/Nb co-doping in 5–8NbTa systems can further optimize the insulation performance of oxygen ions.The oxygen-ion conductivity of 8NbTa(3.31×10^(−6)S cm^(−1),900℃)is about 5 times lower than that of 8HERN(15.8×10^(−6)S cm^(−1),900℃)because of the sluggish diffusion effect,providing better oxygen barrier capacity in 5–8NbTa systems to inhibit the overgrowth of the thermal growth oxide(TGO)of TBCs.In addition,influenced by lattice dis-tortion and solid solution strengthening,the samples possess higher hardness(7.51–8.15 GPa)and TECs(9.78×10^(−6)K−1^(-1)0.78×10^(−6)K^(−1),1500℃)than the single rare-earth niobates and tantalates.Based on their excellent overall properties,it is considered that 5–8NbTa can be used as auspicious TBCs.展开更多
Oil-based drilling fluids possess excellent properties such as shale inhibition, cuttings suspension, and superior lubrication, making them essential in the development of unconventional oil and gas reservoirs.However...Oil-based drilling fluids possess excellent properties such as shale inhibition, cuttings suspension, and superior lubrication, making them essential in the development of unconventional oil and gas reservoirs.However, wellbore instability, caused by the invasion of drilling fluids into shale formations, remains a significant challenge for the safe and efficient extraction of shale oil and gas. This work reports the preparation of mesoporous SiO2nanoparticles with low surface energy, utilized as multifunctional agents to enhance the performance of oil-based drilling fluids aimed at improving wellbore stability. The results indicate that the coating prepared from these nanoparticles exhibit excellent hydrophobicity and antifouling properties, increasing the water contact angle from 32°to 146°and oil contact angle from 24°to134.8°. Additionally, these nanoparticles exhibit exceptional chemical stability and thermal resistance.Incorporating these nanoparticles into oil-based drilling fluids reduced the surface energy of the mud cake from 34.99 to 8.17 m J·m-2and increased the roughness of shale from 0.26 to 2.39 μm. These modifications rendered the mud cake and shale surfaces amphiphobic, effectively mitigating capillary infiltration and delaying the long-term strength degradation of shale in oil-based drilling fluids. After 28days of immersion in oil-based drilling fluid, shale cores treated with MF-SiO2exhibited a 30.5% increase in compressive strength compared to untreated cores. Additionally, these nanoparticles demonstrated the ability to penetrate and seal rock pores, reducing the API filtration volume of the drilling fluid from11.2 to 7.6 m L. This study introduces a novel approach to enhance the development of shale gas and oil resources, offering a promising strategy for wellbore stabilization in oil-based drilling fluid systems.展开更多
The microstructural evolution,phase stability,and mechanical properties of Al-Li-Mg-Ti-M(M=Zn,Zr,V)lightweight high-entropy alloys(LW-HEAs)were investigated.The LW-HEAs with three components,Al_(20)Li_(20)Mg_(10)-Ti_(...The microstructural evolution,phase stability,and mechanical properties of Al-Li-Mg-Ti-M(M=Zn,Zr,V)lightweight high-entropy alloys(LW-HEAs)were investigated.The LW-HEAs with three components,Al_(20)Li_(20)Mg_(10)-Ti_(40)Zn_(10)(#Zn),Al_(20)Li_(20)Mg_(10)Ti_(30)Zr_(20)(#Zr),and Al_(20)Li_(20)Mg_(10)Ti_(30)V_(20)(#V),were designed according to the thermo-dynamic design criteria of HEA,and prepared via a combination process of mechanical alloying and cold-press sintering.The effects of alloy composition and sintering temperature on the microstructure and mechanical properties of the LW-HEAs were studied.The results show that the as-milled Al-Li-Mg-Ti-M(M=Zn,Zr,V)LW-HEAs form a simple structure with HCP-type solid solution as the primary phase,a dual-HCP type solid solution phase,and a BCC phase,respectively.After cold-press sintering,the#Zn and#V alloys undergo obvious phase transformation;while the#Zr alloy with dual-HCP phases exhibits the best phase stability during heat treatment.The#V-750°C alloy demonstrates the maximum hardness and specific strength of HV 595.2 and 625 MPa∙cm3/g,respectively,under the combined effect of solid solution strengthening of BCC phase and precipitation strengthening ofβ-AlTi_(3).Moreover,the#Zr-650°C,#Zr-750°C,and#Zn-650°C alloys are expected to have excellent plasticity.展开更多
Although phase-change random-access memory(PCRAM)is a promising next-generation nonvolatile memory technology,challenges remain in terms of reducing energy consumption.This is primarily be-cause the high thermal condu...Although phase-change random-access memory(PCRAM)is a promising next-generation nonvolatile memory technology,challenges remain in terms of reducing energy consumption.This is primarily be-cause the high thermal conductivities of phase-change materials(PCMs)promote Joule heating dissi-pation.Repeated phase transitions also induce long-range atomic diffusion,limiting the durability.To address these challenges,phase-change heterostructure(PCH)devices that incorporate confinement sub-layers based on transition-metal dichalcogenide materials have been developed.In this study,we engi-neered a PCH device by integrating HfTe_(2),which has low thermal conductivity and excellent stability,into the PCM to realize PCRAM with enhanced thermal efficiency and structural stability.HEAT sim-ulations were conducted to validate the superior heat confinement in the programming region of the HfTe_(2)-based PCH device.Moreover,electrical measurements of the device demonstrated its outstanding performance,which was characterized by a low RESET current(∼1.6 mA),stable two-order ON/OFF ratio,and exceptional cycling endurance(∼2×10^(7)).The structural integrity of the HfTe_(2)confinement sub-layer was confirmed using X-ray photoelectron spectroscopy and transmission electron microscopy.The material properties,including electrical conductivity,cohesive energy,and electronegativity,substantiated these findings.Collectively,these results revealed that the HfTe_(2)-based PCH device can achieve significant improvements in performance and reliability compared with conventional PCRAM devices.展开更多
The intermetallic compounds based on the tetragonal ThMn_(12) prototype crystal structure have exhibited great potential as advanced rare-earth-lean permanent magnets due to their excellent intrinsic magnetic properti...The intermetallic compounds based on the tetragonal ThMn_(12) prototype crystal structure have exhibited great potential as advanced rare-earth-lean permanent magnets due to their excellent intrinsic magnetic properties.However,the trade-off between the phase stability and the magnetic performance is often encountered in the ThMn_(12)-type magnets.This work was focused on the effects of V doping and nanos-tructuring on the phase stability and magnetic properties of ThMn_(12)-type Sm-Co-based magnets.Novel SmCo_(12)-based nanocrystalline alloys with the SmCo_(12) main phase were prepared for the first time.The prepared alloys from the optimal design achieved obviously higher coercivity than the isotropic SmFe_(12)-based alloys,together with comparable performance of other magnetic features.The enhancement in the coercivity was ascribed to the pinning of domain walls by the nanocrystalline grain boundaries and stacking faults.First-principles calculations and magnetic structure analysis disclosed that V substitution can stabilize the SmCo_(12) lattice and elevate its magnetocrystalline anisotropy.This study provides a new approach to developing stabilized metastable structured rare-earth-lean alloys with high magnetic per-formance.展开更多
Lithium metal batteries(LMBs)are emerging as a promising energy storage solution owing to their high energy density and specific capacity.However,the non-uniform plating of lithium and the potential rupture of the sol...Lithium metal batteries(LMBs)are emerging as a promising energy storage solution owing to their high energy density and specific capacity.However,the non-uniform plating of lithium and the potential rupture of the solid-electrolyte interphase(SEI)during extended cycling use may result in dendrite growth,which can penetrate the separator and pose significant short-circuit risks.Forming a stable SEI is essential for the long-term operation of the batteries.Fluorine-rich SEI has garnered significant attention for its ability to effectively passivate electrodes,regulate lithium deposition,and inhibit electrolyte corrosion.Understanding the structural components and preparation methods of existing fluorinated SEI is crucial for optimizing lithium metal anode performance.This paper reviews the research on optimizing LiF passivation interfaces to protect lithium metal anodes.It focuses on four types of compositions in fluorinated SEI that work synergistically to enhance SEI performance.For instance,combining compounds with LiF can further enhance the mechanical strength and ionic conductivity of the SEI.Integrating metals with LiF significantly improves electrochemical performance at the SEI/anode interface,with a necessary focus on reducing electron tunneling risks.Additionally,incorporating polymers with LiF offers balanced improvements in interfacial toughness and ionic conductivity,though maintaining structural stability over long cycles remains a critical area for future research.Although alloys combined with LiF increase surface energy and lithium affinity,challenges such as dendrite growth and volume expansion persist.In summary,this paper emphasizes the crucial role of interfacial structures in LMBs and offers comprehensive guidance for future design and development efforts in battery technology.展开更多
In this paper,we develop a multi-scalar auxiliary variables(MSAV)scheme for the Cahn-Hilliard Magnetohydrodynamics system by introducing two scalar auxiliary variables(SAV).This scheme is linear,fully decoupled and un...In this paper,we develop a multi-scalar auxiliary variables(MSAV)scheme for the Cahn-Hilliard Magnetohydrodynamics system by introducing two scalar auxiliary variables(SAV).This scheme is linear,fully decoupled and unconditionally stable in energy.Subsequently,we provide a detailed implementation procedure for full decoupling.Thus,at each time step,only a series of linear differential equations with constant coefficients need to be solved.To validate the effectiveness of our approach,we conduct an error analysis for this first-order scheme.Finally,some numerical experiments are provided to verify the energy dissipation of the system and the convergence of the proposed approach.展开更多
This study investigates the use of a low-carbon soil stabilizer called SDG,which is made up of granulated blast furnace slag (GGBFS),desulfurization gypsum (DG),and calcium carbide slag (CCS),to solidify the soil.The ...This study investigates the use of a low-carbon soil stabilizer called SDG,which is made up of granulated blast furnace slag (GGBFS),desulfurization gypsum (DG),and calcium carbide slag (CCS),to solidify the soil.The impact of SDG components on the strength and durability of solidified soil was analysed through a series of tests,including unconfined compressive strength,water stability coefficient,water absorption rate,drying-wetting cycles,and shrinkage tests.Furthermore,microstructure characteristics were analysed using X-ray diffraction (XRD) and scanning electron microscopy (SEM).The study shows that the solidified soil has excellent strength and durability when the SDG stabilizer contains 60% GGBGS,10% DG,and 30% CCS.Additionally,increasing the DG content negatively affects the soil's resistance to water.The SDG stabilizer has potential chemical cementitious characteristics and the calcium carbide slag is rich in calcium ions,which undergo an ion exchange reaction with minerals in the soil.These findings offer new ideas for the development of soil stabilizers.展开更多
Purpose: There have been many studies on the effects of different types of backpacks on posture from a biomechanical perspective and on the center of gravity. Considering the effects of autonomic nervous system activi...Purpose: There have been many studies on the effects of different types of backpacks on posture from a biomechanical perspective and on the center of gravity. Considering the effects of autonomic nervous system activity and mood associated with backpacks in mountaineering and hiking, research is also needed from a psychological perspective. In this study, the effects of adjusting the backpack shoulder stabilizer were preliminarily tested in terms of subjective fatigue and changes in autonomic nervous activity after hiking. Methods: The experimental 15 healthy participants hiked the mountain under two conditions: 1) without adjusting the stabilizer, a feature of the backpack (NAH condition), and 2) with the stabilizer adjusted (AH condition). First, all participants hiked the mountain in the NAH condition, and after a 30-minute break, they began the hike in the AH condition after confirming that a) their heart rate had recovered and b) they were in good physical condition. Results: HR was significantly lower after each hiking session than during the session. RMSSD was significantly lower pre-AH and post-AH than the NAH condition, but there was no significant difference between the NAH condition and either post-NAH or post-AH. Additionally, RMSSD was significantly lower in the AH condition than pre-AH or post-AH. The shoulders and back were significantly more burdened in the NAH condition than in the AH condition. The pleasure level was significantly higher in the AH condition than in the NAH condition. Conclusion: The results showed that also adjusting the position of the waist belt when adjusting the shoulder stabilizer, which is mainly used for the neck and shoulders, has a significant positive effect on the subjective burden on the upper body and parasympathetic nervous system activity after hiking.展开更多
The integration of renewable energy sources(RESs)with inverter interfaces has fundamentally reshaped power system dynamics,challenging traditional stability analysis frameworks designed for synchronous generator-domin...The integration of renewable energy sources(RESs)with inverter interfaces has fundamentally reshaped power system dynamics,challenging traditional stability analysis frameworks designed for synchronous generator-dominated grids.Conventional classifica-tions,which decouple voltage,frequency,and rotor angle stability,fail to address the emerging strong voltage‒angle coupling effects caused by RES dynamics.This coupling introduces complex oscillation modes and undermines system robustness,neces-sitating novel stability assessment tools.Recent studies focus on eigenvalue distributions and damping redistribution but lack quantitative criteria and interpretative clarity for coupled stability.This work proposes a transient energy-based framework to resolve these gaps.By decomposing transient energy into subsystem-dissipated components and coupling-induced energy exchange,the method establishes stability criteria compatible with a broad variety of inverter-interfaced devices while offering an intuitive energy-based interpretation for engineers.The coupling strength is also quantified by defining the relative coupling strength index,which is directly related to the transient energy interpretation of the coupled stability.Angle‒voltage coupling may induce instability by injecting transient energy into the system,even if the individual phase angle and voltage dynamics themselves are stable.The main contributions include a systematic stability evaluation framework and an energy decomposition approach that bridges theoretical analysis with practical applicability,addressing the urgent need for tools for managing modern power system evolving stability challenges.展开更多
In order to increase the stability of the Mongolia power system, a single-phase automatic reclosing device (SPAR) was introduced on double-circuit power lines built with a size of 330 kV, operating on a voltage of 220...In order to increase the stability of the Mongolia power system, a single-phase automatic reclosing device (SPAR) was introduced on double-circuit power lines built with a size of 330 kV, operating on a voltage of 220 kV and a length of 250 km. These overhead power lines (L-213, L-214) connect the 220/110/35 kV “Songino” substation with the “Mandal” substation and form system networks. This paper presents the challenges encountered when implementing single-phase automatic reclosing (SPAR) devices and compares the changes in power system parameters before and after SPAR deployment for a long 220 kV line. Simulations and analyses were carried out using DIgSILENT PowerFactory software, focusing on rotor angle stability, and the overall impact on the power system during short-circuit faults. The evaluation also utilized measurement data from the Wide Area Monitoring System (WAMS) to compare system behavior pre- and post-implementation of SPAR. The findings reveal that SPAR significantly enhances system reliability and stability, effectively mitigating the risk of oscillations and stability loss triggered by short circuits. This improvement contributes to a more resilient power system, reducing the potential for disturbances caused by faults.展开更多
Dear Editor,This letter deals with the stabilization problem of nonlinear stochastic systems via self-triggered impulsive control(STIC), where the timing of impulsive control actions is not dependent on continuous sta...Dear Editor,This letter deals with the stabilization problem of nonlinear stochastic systems via self-triggered impulsive control(STIC), where the timing of impulsive control actions is not dependent on continuous state monitoring. In contrast to the existing self-triggered control method, novel self-triggered mechanism(STM) is proposed by incorporating a waiting time for stabilizing impulses. This allows for direct prediction of the next impulsive instant.展开更多
The hydrothermal stability of zeolites is essential for their potential applications in biomass conversion,especially in processes involving elevated temperatures alongside the use or generation of H_(2)O.In this stud...The hydrothermal stability of zeolites is essential for their potential applications in biomass conversion,especially in processes involving elevated temperatures alongside the use or generation of H_(2)O.In this study,we employed F-ions as mineralizers to synthesize hydrothermally stable ZSM-5 zeolites under acidic conditions.The acidic synthesis system promotes zeolites with fewer silanol-terminated lattice defects(ZSM-5(A))compared to the traditional basic conditions(ZSM-5(B)),endowing materials with substantially higher structural integrity and hydrophobicity.After 10 days of autoclave treatment at 200℃ in aqueous phase,H-ZSM-5(A)demonstrated nearly unchanged reaction rates in the dehydration of cyclohexanol,while H-ZSM-5(B)lost>50%of the dehydration activity.Additionally,H-ZSM-5(A)delivered higher initial dehydration rates compared to H-ZSM-5(B).The different measured activation energies further revealed variations in reaction pathways during cyclohexanol dehydration,i.e.,the monomer-or dimer-mediated routes depending on the concentration of alcohol molecule within zeolite pores,providing additional evidence for the strengthened hydrophobic nature of H-ZSM-5(A).Beyond this,the zeolite surface properties and the strength of cyclohexanol-zeolite interactions may impose additional transport/adsorption barriers attributed to multi-phase phenomena on the more polar H-ZSM-5(B)zeolite surfaces.More importantly,the hydrothermal treatment did not induce significant desilication and dealumination in H-ZSM-5(A),thereby preserving its active acid sites and ensuring exceptional hydrothermal stability.The present work fundamentally studies the synthesis of hydrothermally stable zeolites in an acidic medium using fluorides and expands the understanding of polar interactions in catalysis,characterized by the dehydration of cyclohexanol,for future application in biomass conversion.展开更多
This study focuses on the preparation,and optimization of the nanoemulsions coorporating with pumpkin seed oil,grape seed oil,and grapefruit essential oil using the phase inversion temperature(PIT)technique.The resear...This study focuses on the preparation,and optimization of the nanoemulsions coorporating with pumpkin seed oil,grape seed oil,and grapefruit essential oil using the phase inversion temperature(PIT)technique.The research investigated the impact of surfactant types and concentrations on critical nanoemulsion properties,including droplet size,polydispersity index(PDI),and zeta potential.Using a Box-Behnken Design(BBD)model,the formulation was optimized containing 6.0%plant oils,10.0%Tween 80,2.0%Span 80,and 1.0%lecithin to achieve nano-sized droplets(33.52 nm),with a low PDI(0.205),and a stable zeta potential(15.49 mV).The antioxidant activity,was evaluated through 2,2-diphenyl-1-picrylhydrazyl(DPPH)radical scavenging assays,demonstrating its outstanding efficacy.And the optimized nanoemulsion showed a radical-scavenging capacity exceeding 2250μg ascorbic acid equivalents/g,significantly outperforming non-nanoemulsified oils.Stability testing under various environmental conditions highlighted exceptional robustness,with refrigerated samples maintaining structural integrity,minimal particle size growth,and consistent physicochemical properties over a 30-day storage period.The results suggest that the plant oil-based nanoemulsions exhibit strong antioxidant potential,offering a promising natural treatment for their application in cosmeceutical and therapeutic formulations.展开更多
High-temperature infrared(IR)radiation materials with broadband high emissivity,low thermal conductivity,and high fracture toughness are urgently needed for radiative heat management.Here,we report a Gd_(3)TaO_(7)/GdF...High-temperature infrared(IR)radiation materials with broadband high emissivity,low thermal conductivity,and high fracture toughness are urgently needed for radiative heat management.Here,we report a Gd_(3)TaO_(7)/GdFeO_(3)composite ceramic that integrates a broadband(0.78-14μm)high emissivity(close to 0.9),low thermal conductivity(1.62Wm^(−1)K^(−1)),and fracture toughness(2.3MPam^(1/2),close to YSZ).Through the introduction of second-phase GdFeO_(3),many lattice distortions,multimode vibrations,and additional oxygen vacancies(Ov)contribute to an increase in the broad-band emissivity of the composite ceramics(especially in the 2.5-6μm band,nearly 5 times greater than that of Gd_(3)TaO_(7)).This high IR emissivity significantly suppresses the elevated photonic thermal conductivity at high temperatures,resulting in ultralow thermal conductivity.Moreover,the stable atomic arrangement within the two phases contributed to the impressive high-temperature stability(1773K,200h).The improved fracture toughness is attributed primarily to the presence of the second phase promoting crack tip deflection,bridging and branching,which prevent crack expansion.All the advantages render this second-phase composite strategy fully competitive in the development of a new generation of superhigh-temperature radiative heat management materials.展开更多
The numerical approximation of stochastic partial differential equations(SPDEs),particularly those including q-diffusion,poses considerable challenges due to the requirements for high-order precision,stability amongst...The numerical approximation of stochastic partial differential equations(SPDEs),particularly those including q-diffusion,poses considerable challenges due to the requirements for high-order precision,stability amongst random perturbations,and processing efficiency.Because of their simplicity,conventional numerical techniques like the Euler-Maruyama method are frequently employed to solve stochastic differential equations;nonetheless,they may have low-order accuracy and lower stability in stiff or high-resolution situations.This study proposes a novel computational scheme for solving SPDEs arising from a stochastic SEIR model with q-diffusion and a general incidence rate function.A proposed computational scheme can be used to solve stochastic partial differential equations.For spatial discretization,a compact scheme is chosen.The compact scheme can provide a sixth-order accurate solution.The proposed scheme can be considered an extension of the Euler Maruyama method.Stability and consistency in the mean square sense are also provided.For application purposes,the stochastic SEIR model is considered using q-diffusion effects.The scheme is used to solve the stochastic model and compared with the Euler-Maruyama method.The scheme is also compared with nonstandard finite difference method for solving deterministic models.In both cases,it performs better than existing schemes.Incorporating q-diffusion further enhanced the model’s ability to represent realistic spatial-temporal disease dynamics,especially in scenarios where classical diffusion is insufficient.展开更多
The unique oxygen stacking sequence of O2-type structures restricts the irreversible transition metal movement into Li vacancies for the delithiated Li-rich layered oxides(LLOs)and maintains outstanding voltage stabil...The unique oxygen stacking sequence of O2-type structures restricts the irreversible transition metal movement into Li vacancies for the delithiated Li-rich layered oxides(LLOs)and maintains outstanding voltage stability.However,the ion-exchange synthesis promotes the Mn-ion valence reduction and aggravates the Jahn-Teller(J-T)distortion alongside disproportionation.Since the main oxidation state of the Mn ions is+4 in the traditional O3-type LLOs,synergistic effects of the O2-type and O3-type structures are expected in the O2/O3 diphasic Li-rich material.Herein,O2/O3 biphasic intergrowth LLOs were rationally designed,and the synergic optimization of the biphasic structure was planned to retard the J-T effect.The O2/O3 intergrowth nature was confirmed,and the percentages of the O2 and O3 phases were 56%and 44%,respectively.Density functional theory calculations demonstrated that the Mn^(2+)(EC)sheath had a remarkably lower energy barrier than the Li^(+)(EC)sheath.This finding suggests that Mn^(2+)ions that are dissolved into the electrolyte accelerate the electrolyte oxidization,so the deposition of the cathode electrolyte interface for pristine O2-LLOs causes a high electrochemical impedance.The designed O2/O3 biphasic LLOs boost the capacity stability and suppress the voltage drop upon repeated Li^(+)de-intercalation.The phase regulation strategy offers great potential for developing low-cost LLOs with enhanced structural stability for advanced Li-ion batteries.展开更多
Flexible phase change materials(PCMs)have become increasingly critical to address the demand for thermal management in electronic technologies and energy conversion.However,their application remains challenging becaus...Flexible phase change materials(PCMs)have become increasingly critical to address the demand for thermal management in electronic technologies and energy conversion.However,their application remains challenging because of their rigidity,liquid leakage,and insufficient thermal conductivity.Herein,flexible glutamic acid@natural rubber/paraffin wax(PW)/carbon nanotubes-graphene nanoplatelets(GNR/PW/CGNP)phase change composites with high thermal conductivity,excellent shape stability,and recyclability were reported.Zn^(2+)-based dynamic crosslinking was constructed through the reaction of zinc acetate and carboxyl groups on glutamic acid@natural rubber(GNR),which was used as a flexible matrix to physically blend with paraffin wax/carbon nanotubes/graphene nanoplatelets(PW/CGNP)to achieve uniform dispersion of PW/CGNP,continuous thermal conductivity networks,and good encapsulation of PW.The GNR/PW/CGNP composites showed excellent mechanical strength,flexibility,and recycling ability,and effective encapsulation prevented the outflow of melted PW during the phase transition.Also,the phase change enthalpy could attain 111.1 J/g with a higher thermal conductivity of 1.055 W/m K,428%higher than that of pure PW owing to the formation of efficient thermal conductive pathways,which exhibited outstanding thermal management performance and superior temperature control behavior in electronic devices.The developed flexible composite PCMs may open new possibilities for next-generation flexible thermal management electronics.展开更多
This research presents an advanced study on the modeling and stability analysis of electro-hydraulic control modules used in intelligent chassis systems.Firstly,a comprehensive nonlinear mathematical model of the elec...This research presents an advanced study on the modeling and stability analysis of electro-hydraulic control modules used in intelligent chassis systems.Firstly,a comprehensive nonlinear mathematical model of the electro-hydraulic power-shift system is developed,incorporating pipeline characteristics through impedance analysis and examining coupling effects between the pilot solenoid valve,main valve,and pipeline.Then,the model’s accuracy is validated through experimental testing,demonstrating high precision and minimal model errors.A comparative analysis between simulation data(both with and without pipeline characteristics)and experimental results reveals that the model considering pipeline parameters aligns more closely with experimental data,highlighting its superior accuracy.The research further explores the influence of key factors on system stability,including damping coefficient,feedback cavity orifice diameter,spring stiffness,pipeline length,and pipeline diameter.Significant findings include the critical impact of damping coefficient,orifice diameter,and pipeline length on stability,while spring stiffness has a minimal effect.These findings provide valuable insights for optimizing electro-hydraulic control modules in intelligent chassis systems,with practical implications for automotive and construction machinery applications.展开更多
基金the financial supports from the National Natural Science Foundation of China (Nos. 51974116, 51874128)the Science Foundation of Hunan Province, China (Nos. 2020JJ4273, 2020JJ5130)。
文摘Palladium-supported cobalt hydroxide(Co(OH)_(2)-Pd) nanoplates were fabricated in an aqueous solution and employed as a catalyst for the reduction of 4-nitrophenol.For the preparation of Co(OH)2-Pd,Pd nanoparticles were anchored on the Co(OH)_(2) nanoplates after the reduction of Na;PdCl;by ascorbic acid in the absence of a stabilizer at room temperature.The observations under transmission and scanning electron microscopy reveal that Pd nanoparticles with a size of 2-5 nm are uniformly dispersed on the surface of the Co(OH)_(2) nanoplates.In catalytic test,the conversion of 4-nitrophenol to 4-aminophenol is completed within 6 min in the presence of Co(OH)_(2)-Pd(1000) nanoplates with2.18 at.% Pd,and the corresponding kinetic constant is 0.0089 s;in the first test.The catalyst retains relatively high activity after several cycles.The results demonstrate that the Co(OH)_(2)-Pd(1000) nanoplates exhibit high catalytic activity toward the reduction of 4-nitrophenol in the presence of NaBH;.
基金support from Yunnan Major Scientific and Technological Projects(No.202302AG050010)Yunnan Fundamental Research Projects(Nos.202101AW070011 and202101BE070001–015)+1 种基金National Natural Science Foundation of China(No.52303295)Project Funds of“Xingdian Talent Support Program”.
文摘Improving and optimizing the target properties of ceramics via the high entropy strategy has attracted significant attention.Rare earth niobate is a potential thermal barrier coating(TBCs)material,but its poor high-temperature phase stability limits its further application.In this work,four sets of TBCs high-entropy ceramics,(Sm_(1/5)Dy_(1/5)Ho_(1/5)Er_(1/5)Yb_(1/5))(Nb_(1/2)Ta_(1/2))O_(4)(5NbTa),(Sm_(1/6)Dy_(1/6)Ho_(1/6)Er_(1/6)Yb_(1/6)Lu_(1/6))(Nb_(1/2)Ta_(1/2))O_(4)(6NbTa),(Sm_(1/7)Gd_(1/7)Dy_(1/7)Ho_(1/7)Er_(1/7)Yb_(1/7)Lu_(1/7))(Nb_(1/2)Ta_(1/2))O_(4)(7NbTa),(Sm_(1/8)Gd_(1/8)Dy_(1/8)Ho_(1/8)Er_(1/8)Tm_(1/8)Yb_(1/8)Lu_(1/8))(Nb_(1/2)Ta_(1/2))O_(4)(8NbTa)are synthesized using a solid-state reaction method at 1650℃for 6 h.Firstly,the X-ray diffractometer(XRD)patterns display that the samples are all single-phase solid solution structures(space group C 2/c).Differential scanning calorimetry(DSC)and the high-temperature XRD of 8NbTa cross-check that the addition of Ta element in 8HERN increases the phase transition temperature above 1400℃,which can be attributed to that the Ta/Nb co-doping at B site introduces the fluctuation of the bond strength of Ta-O and Nb-O.Secondly,compared to high-entropy rare-earth niobates,the introduction of Ta atoms at B site substantially reduce thermal conductivity(re-duced by 44%,800℃)with the seven components high entropy ceramic as an example.The low thermal conductivity means strong phonon scattering,which may originate from the softening acoustic mode and flattened phonon dispersion in 5–8 principal element high entropy rare earth niobium tantalates(5–8NbTa)revealed by the first-principles calculations.Thirdly,the Ta/Nb co-doping in 5–8NbTa systems can further optimize the insulation performance of oxygen ions.The oxygen-ion conductivity of 8NbTa(3.31×10^(−6)S cm^(−1),900℃)is about 5 times lower than that of 8HERN(15.8×10^(−6)S cm^(−1),900℃)because of the sluggish diffusion effect,providing better oxygen barrier capacity in 5–8NbTa systems to inhibit the overgrowth of the thermal growth oxide(TGO)of TBCs.In addition,influenced by lattice dis-tortion and solid solution strengthening,the samples possess higher hardness(7.51–8.15 GPa)and TECs(9.78×10^(−6)K−1^(-1)0.78×10^(−6)K^(−1),1500℃)than the single rare-earth niobates and tantalates.Based on their excellent overall properties,it is considered that 5–8NbTa can be used as auspicious TBCs.
基金support from the National Natural:Science Foundation of China(NO.52174014)the National Natural Science Foundation Basic Science Center(NO.52288101).
文摘Oil-based drilling fluids possess excellent properties such as shale inhibition, cuttings suspension, and superior lubrication, making them essential in the development of unconventional oil and gas reservoirs.However, wellbore instability, caused by the invasion of drilling fluids into shale formations, remains a significant challenge for the safe and efficient extraction of shale oil and gas. This work reports the preparation of mesoporous SiO2nanoparticles with low surface energy, utilized as multifunctional agents to enhance the performance of oil-based drilling fluids aimed at improving wellbore stability. The results indicate that the coating prepared from these nanoparticles exhibit excellent hydrophobicity and antifouling properties, increasing the water contact angle from 32°to 146°and oil contact angle from 24°to134.8°. Additionally, these nanoparticles exhibit exceptional chemical stability and thermal resistance.Incorporating these nanoparticles into oil-based drilling fluids reduced the surface energy of the mud cake from 34.99 to 8.17 m J·m-2and increased the roughness of shale from 0.26 to 2.39 μm. These modifications rendered the mud cake and shale surfaces amphiphobic, effectively mitigating capillary infiltration and delaying the long-term strength degradation of shale in oil-based drilling fluids. After 28days of immersion in oil-based drilling fluid, shale cores treated with MF-SiO2exhibited a 30.5% increase in compressive strength compared to untreated cores. Additionally, these nanoparticles demonstrated the ability to penetrate and seal rock pores, reducing the API filtration volume of the drilling fluid from11.2 to 7.6 m L. This study introduces a novel approach to enhance the development of shale gas and oil resources, offering a promising strategy for wellbore stabilization in oil-based drilling fluid systems.
基金financially supported by China Aeronautical Science Foundation (No.2023Z0530Q9002)the Program for Chongqing Talents,China (No.cstc2024ycjh-bgzxm0066)。
文摘The microstructural evolution,phase stability,and mechanical properties of Al-Li-Mg-Ti-M(M=Zn,Zr,V)lightweight high-entropy alloys(LW-HEAs)were investigated.The LW-HEAs with three components,Al_(20)Li_(20)Mg_(10)-Ti_(40)Zn_(10)(#Zn),Al_(20)Li_(20)Mg_(10)Ti_(30)Zr_(20)(#Zr),and Al_(20)Li_(20)Mg_(10)Ti_(30)V_(20)(#V),were designed according to the thermo-dynamic design criteria of HEA,and prepared via a combination process of mechanical alloying and cold-press sintering.The effects of alloy composition and sintering temperature on the microstructure and mechanical properties of the LW-HEAs were studied.The results show that the as-milled Al-Li-Mg-Ti-M(M=Zn,Zr,V)LW-HEAs form a simple structure with HCP-type solid solution as the primary phase,a dual-HCP type solid solution phase,and a BCC phase,respectively.After cold-press sintering,the#Zn and#V alloys undergo obvious phase transformation;while the#Zr alloy with dual-HCP phases exhibits the best phase stability during heat treatment.The#V-750°C alloy demonstrates the maximum hardness and specific strength of HV 595.2 and 625 MPa∙cm3/g,respectively,under the combined effect of solid solution strengthening of BCC phase and precipitation strengthening ofβ-AlTi_(3).Moreover,the#Zr-650°C,#Zr-750°C,and#Zn-650°C alloys are expected to have excellent plasticity.
基金financially supported by a National Research Foundation of Korea(NRF)grant funded by the Korean government(No.2016R1A3B1908249,RS202400407199).
文摘Although phase-change random-access memory(PCRAM)is a promising next-generation nonvolatile memory technology,challenges remain in terms of reducing energy consumption.This is primarily be-cause the high thermal conductivities of phase-change materials(PCMs)promote Joule heating dissi-pation.Repeated phase transitions also induce long-range atomic diffusion,limiting the durability.To address these challenges,phase-change heterostructure(PCH)devices that incorporate confinement sub-layers based on transition-metal dichalcogenide materials have been developed.In this study,we engi-neered a PCH device by integrating HfTe_(2),which has low thermal conductivity and excellent stability,into the PCM to realize PCRAM with enhanced thermal efficiency and structural stability.HEAT sim-ulations were conducted to validate the superior heat confinement in the programming region of the HfTe_(2)-based PCH device.Moreover,electrical measurements of the device demonstrated its outstanding performance,which was characterized by a low RESET current(∼1.6 mA),stable two-order ON/OFF ratio,and exceptional cycling endurance(∼2×10^(7)).The structural integrity of the HfTe_(2)confinement sub-layer was confirmed using X-ray photoelectron spectroscopy and transmission electron microscopy.The material properties,including electrical conductivity,cohesive energy,and electronegativity,substantiated these findings.Collectively,these results revealed that the HfTe_(2)-based PCH device can achieve significant improvements in performance and reliability compared with conventional PCRAM devices.
基金supported by the National Key R&D Program of China(Nos.2021YFB3501502 and 2021YFB3501504).
文摘The intermetallic compounds based on the tetragonal ThMn_(12) prototype crystal structure have exhibited great potential as advanced rare-earth-lean permanent magnets due to their excellent intrinsic magnetic properties.However,the trade-off between the phase stability and the magnetic performance is often encountered in the ThMn_(12)-type magnets.This work was focused on the effects of V doping and nanos-tructuring on the phase stability and magnetic properties of ThMn_(12)-type Sm-Co-based magnets.Novel SmCo_(12)-based nanocrystalline alloys with the SmCo_(12) main phase were prepared for the first time.The prepared alloys from the optimal design achieved obviously higher coercivity than the isotropic SmFe_(12)-based alloys,together with comparable performance of other magnetic features.The enhancement in the coercivity was ascribed to the pinning of domain walls by the nanocrystalline grain boundaries and stacking faults.First-principles calculations and magnetic structure analysis disclosed that V substitution can stabilize the SmCo_(12) lattice and elevate its magnetocrystalline anisotropy.This study provides a new approach to developing stabilized metastable structured rare-earth-lean alloys with high magnetic per-formance.
基金support from the National Natural Science Foundation of China(No.U2333210)the Sichuan Science and Technology Program,China(No.21SYSX0011)。
文摘Lithium metal batteries(LMBs)are emerging as a promising energy storage solution owing to their high energy density and specific capacity.However,the non-uniform plating of lithium and the potential rupture of the solid-electrolyte interphase(SEI)during extended cycling use may result in dendrite growth,which can penetrate the separator and pose significant short-circuit risks.Forming a stable SEI is essential for the long-term operation of the batteries.Fluorine-rich SEI has garnered significant attention for its ability to effectively passivate electrodes,regulate lithium deposition,and inhibit electrolyte corrosion.Understanding the structural components and preparation methods of existing fluorinated SEI is crucial for optimizing lithium metal anode performance.This paper reviews the research on optimizing LiF passivation interfaces to protect lithium metal anodes.It focuses on four types of compositions in fluorinated SEI that work synergistically to enhance SEI performance.For instance,combining compounds with LiF can further enhance the mechanical strength and ionic conductivity of the SEI.Integrating metals with LiF significantly improves electrochemical performance at the SEI/anode interface,with a necessary focus on reducing electron tunneling risks.Additionally,incorporating polymers with LiF offers balanced improvements in interfacial toughness and ionic conductivity,though maintaining structural stability over long cycles remains a critical area for future research.Although alloys combined with LiF increase surface energy and lithium affinity,challenges such as dendrite growth and volume expansion persist.In summary,this paper emphasizes the crucial role of interfacial structures in LMBs and offers comprehensive guidance for future design and development efforts in battery technology.
基金Research Project Supported by Shanxi Scholarship Council of China(2021-029)International Cooperation Base and Platform Project of Shanxi Province(202104041101019)Basic Research Plan of Shanxi Province(202203021211129)。
文摘In this paper,we develop a multi-scalar auxiliary variables(MSAV)scheme for the Cahn-Hilliard Magnetohydrodynamics system by introducing two scalar auxiliary variables(SAV).This scheme is linear,fully decoupled and unconditionally stable in energy.Subsequently,we provide a detailed implementation procedure for full decoupling.Thus,at each time step,only a series of linear differential equations with constant coefficients need to be solved.To validate the effectiveness of our approach,we conduct an error analysis for this first-order scheme.Finally,some numerical experiments are provided to verify the energy dissipation of the system and the convergence of the proposed approach.
基金Funded by the National Key R&D Program of China (No. 2022YFC3803405)the China State Construction Key Laboratory Project (No. ZJXJ-PT-2022-14)。
文摘This study investigates the use of a low-carbon soil stabilizer called SDG,which is made up of granulated blast furnace slag (GGBFS),desulfurization gypsum (DG),and calcium carbide slag (CCS),to solidify the soil.The impact of SDG components on the strength and durability of solidified soil was analysed through a series of tests,including unconfined compressive strength,water stability coefficient,water absorption rate,drying-wetting cycles,and shrinkage tests.Furthermore,microstructure characteristics were analysed using X-ray diffraction (XRD) and scanning electron microscopy (SEM).The study shows that the solidified soil has excellent strength and durability when the SDG stabilizer contains 60% GGBGS,10% DG,and 30% CCS.Additionally,increasing the DG content negatively affects the soil's resistance to water.The SDG stabilizer has potential chemical cementitious characteristics and the calcium carbide slag is rich in calcium ions,which undergo an ion exchange reaction with minerals in the soil.These findings offer new ideas for the development of soil stabilizers.
文摘Purpose: There have been many studies on the effects of different types of backpacks on posture from a biomechanical perspective and on the center of gravity. Considering the effects of autonomic nervous system activity and mood associated with backpacks in mountaineering and hiking, research is also needed from a psychological perspective. In this study, the effects of adjusting the backpack shoulder stabilizer were preliminarily tested in terms of subjective fatigue and changes in autonomic nervous activity after hiking. Methods: The experimental 15 healthy participants hiked the mountain under two conditions: 1) without adjusting the stabilizer, a feature of the backpack (NAH condition), and 2) with the stabilizer adjusted (AH condition). First, all participants hiked the mountain in the NAH condition, and after a 30-minute break, they began the hike in the AH condition after confirming that a) their heart rate had recovered and b) they were in good physical condition. Results: HR was significantly lower after each hiking session than during the session. RMSSD was significantly lower pre-AH and post-AH than the NAH condition, but there was no significant difference between the NAH condition and either post-NAH or post-AH. Additionally, RMSSD was significantly lower in the AH condition than pre-AH or post-AH. The shoulders and back were significantly more burdened in the NAH condition than in the AH condition. The pleasure level was significantly higher in the AH condition than in the NAH condition. Conclusion: The results showed that also adjusting the position of the waist belt when adjusting the shoulder stabilizer, which is mainly used for the neck and shoulders, has a significant positive effect on the subjective burden on the upper body and parasympathetic nervous system activity after hiking.
基金supported by the Science and Technology Project of China Southern Power Grid Co.,Ltd under Grant 036000KC23090004(GDKJXM20231026).
文摘The integration of renewable energy sources(RESs)with inverter interfaces has fundamentally reshaped power system dynamics,challenging traditional stability analysis frameworks designed for synchronous generator-dominated grids.Conventional classifica-tions,which decouple voltage,frequency,and rotor angle stability,fail to address the emerging strong voltage‒angle coupling effects caused by RES dynamics.This coupling introduces complex oscillation modes and undermines system robustness,neces-sitating novel stability assessment tools.Recent studies focus on eigenvalue distributions and damping redistribution but lack quantitative criteria and interpretative clarity for coupled stability.This work proposes a transient energy-based framework to resolve these gaps.By decomposing transient energy into subsystem-dissipated components and coupling-induced energy exchange,the method establishes stability criteria compatible with a broad variety of inverter-interfaced devices while offering an intuitive energy-based interpretation for engineers.The coupling strength is also quantified by defining the relative coupling strength index,which is directly related to the transient energy interpretation of the coupled stability.Angle‒voltage coupling may induce instability by injecting transient energy into the system,even if the individual phase angle and voltage dynamics themselves are stable.The main contributions include a systematic stability evaluation framework and an energy decomposition approach that bridges theoretical analysis with practical applicability,addressing the urgent need for tools for managing modern power system evolving stability challenges.
文摘In order to increase the stability of the Mongolia power system, a single-phase automatic reclosing device (SPAR) was introduced on double-circuit power lines built with a size of 330 kV, operating on a voltage of 220 kV and a length of 250 km. These overhead power lines (L-213, L-214) connect the 220/110/35 kV “Songino” substation with the “Mandal” substation and form system networks. This paper presents the challenges encountered when implementing single-phase automatic reclosing (SPAR) devices and compares the changes in power system parameters before and after SPAR deployment for a long 220 kV line. Simulations and analyses were carried out using DIgSILENT PowerFactory software, focusing on rotor angle stability, and the overall impact on the power system during short-circuit faults. The evaluation also utilized measurement data from the Wide Area Monitoring System (WAMS) to compare system behavior pre- and post-implementation of SPAR. The findings reveal that SPAR significantly enhances system reliability and stability, effectively mitigating the risk of oscillations and stability loss triggered by short circuits. This improvement contributes to a more resilient power system, reducing the potential for disturbances caused by faults.
基金supported by the National Natural Science Foundation of China(62403393,12202058,62103118)the China Postdoctoral Science Foundation(2021T140160,2023 T160051)the Natural Science Foundation of Chongqing(CSTB 2023NSCQ-MSX0152)
文摘Dear Editor,This letter deals with the stabilization problem of nonlinear stochastic systems via self-triggered impulsive control(STIC), where the timing of impulsive control actions is not dependent on continuous state monitoring. In contrast to the existing self-triggered control method, novel self-triggered mechanism(STM) is proposed by incorporating a waiting time for stabilizing impulses. This allows for direct prediction of the next impulsive instant.
文摘The hydrothermal stability of zeolites is essential for their potential applications in biomass conversion,especially in processes involving elevated temperatures alongside the use or generation of H_(2)O.In this study,we employed F-ions as mineralizers to synthesize hydrothermally stable ZSM-5 zeolites under acidic conditions.The acidic synthesis system promotes zeolites with fewer silanol-terminated lattice defects(ZSM-5(A))compared to the traditional basic conditions(ZSM-5(B)),endowing materials with substantially higher structural integrity and hydrophobicity.After 10 days of autoclave treatment at 200℃ in aqueous phase,H-ZSM-5(A)demonstrated nearly unchanged reaction rates in the dehydration of cyclohexanol,while H-ZSM-5(B)lost>50%of the dehydration activity.Additionally,H-ZSM-5(A)delivered higher initial dehydration rates compared to H-ZSM-5(B).The different measured activation energies further revealed variations in reaction pathways during cyclohexanol dehydration,i.e.,the monomer-or dimer-mediated routes depending on the concentration of alcohol molecule within zeolite pores,providing additional evidence for the strengthened hydrophobic nature of H-ZSM-5(A).Beyond this,the zeolite surface properties and the strength of cyclohexanol-zeolite interactions may impose additional transport/adsorption barriers attributed to multi-phase phenomena on the more polar H-ZSM-5(B)zeolite surfaces.More importantly,the hydrothermal treatment did not induce significant desilication and dealumination in H-ZSM-5(A),thereby preserving its active acid sites and ensuring exceptional hydrothermal stability.The present work fundamentally studies the synthesis of hydrothermally stable zeolites in an acidic medium using fluorides and expands the understanding of polar interactions in catalysis,characterized by the dehydration of cyclohexanol,for future application in biomass conversion.
基金Ho Chi Minh City University of Technology(HCMUT),VNU-HCM,for supporting this study.
文摘This study focuses on the preparation,and optimization of the nanoemulsions coorporating with pumpkin seed oil,grape seed oil,and grapefruit essential oil using the phase inversion temperature(PIT)technique.The research investigated the impact of surfactant types and concentrations on critical nanoemulsion properties,including droplet size,polydispersity index(PDI),and zeta potential.Using a Box-Behnken Design(BBD)model,the formulation was optimized containing 6.0%plant oils,10.0%Tween 80,2.0%Span 80,and 1.0%lecithin to achieve nano-sized droplets(33.52 nm),with a low PDI(0.205),and a stable zeta potential(15.49 mV).The antioxidant activity,was evaluated through 2,2-diphenyl-1-picrylhydrazyl(DPPH)radical scavenging assays,demonstrating its outstanding efficacy.And the optimized nanoemulsion showed a radical-scavenging capacity exceeding 2250μg ascorbic acid equivalents/g,significantly outperforming non-nanoemulsified oils.Stability testing under various environmental conditions highlighted exceptional robustness,with refrigerated samples maintaining structural integrity,minimal particle size growth,and consistent physicochemical properties over a 30-day storage period.The results suggest that the plant oil-based nanoemulsions exhibit strong antioxidant potential,offering a promising natural treatment for their application in cosmeceutical and therapeutic formulations.
基金supports from the NSFC Grant nos.52301084,U21B2053,and 52301085Postdoctoral Fellowship Program of CPSF(YJB20240056)+3 种基金Aeronautical Science Foundation(2023M045077001)Open Project Funding of State Key Laboratory for High Performance Tools(GXNGJSKL 2024)Opening Project Fund of Materials Service Safety Assessment Facilities(MSAF-2024-007)the Fundamental Research Funds for the Central Universities are gratefully acknowledged.
文摘High-temperature infrared(IR)radiation materials with broadband high emissivity,low thermal conductivity,and high fracture toughness are urgently needed for radiative heat management.Here,we report a Gd_(3)TaO_(7)/GdFeO_(3)composite ceramic that integrates a broadband(0.78-14μm)high emissivity(close to 0.9),low thermal conductivity(1.62Wm^(−1)K^(−1)),and fracture toughness(2.3MPam^(1/2),close to YSZ).Through the introduction of second-phase GdFeO_(3),many lattice distortions,multimode vibrations,and additional oxygen vacancies(Ov)contribute to an increase in the broad-band emissivity of the composite ceramics(especially in the 2.5-6μm band,nearly 5 times greater than that of Gd_(3)TaO_(7)).This high IR emissivity significantly suppresses the elevated photonic thermal conductivity at high temperatures,resulting in ultralow thermal conductivity.Moreover,the stable atomic arrangement within the two phases contributed to the impressive high-temperature stability(1773K,200h).The improved fracture toughness is attributed primarily to the presence of the second phase promoting crack tip deflection,bridging and branching,which prevent crack expansion.All the advantages render this second-phase composite strategy fully competitive in the development of a new generation of superhigh-temperature radiative heat management materials.
基金supported and funded by the Deanship of Scientific Research at Imam Mohammad Ibn Saud Islamic University(IMSIU)(grant number IMSIU-DDRSP2501).
文摘The numerical approximation of stochastic partial differential equations(SPDEs),particularly those including q-diffusion,poses considerable challenges due to the requirements for high-order precision,stability amongst random perturbations,and processing efficiency.Because of their simplicity,conventional numerical techniques like the Euler-Maruyama method are frequently employed to solve stochastic differential equations;nonetheless,they may have low-order accuracy and lower stability in stiff or high-resolution situations.This study proposes a novel computational scheme for solving SPDEs arising from a stochastic SEIR model with q-diffusion and a general incidence rate function.A proposed computational scheme can be used to solve stochastic partial differential equations.For spatial discretization,a compact scheme is chosen.The compact scheme can provide a sixth-order accurate solution.The proposed scheme can be considered an extension of the Euler Maruyama method.Stability and consistency in the mean square sense are also provided.For application purposes,the stochastic SEIR model is considered using q-diffusion effects.The scheme is used to solve the stochastic model and compared with the Euler-Maruyama method.The scheme is also compared with nonstandard finite difference method for solving deterministic models.In both cases,it performs better than existing schemes.Incorporating q-diffusion further enhanced the model’s ability to represent realistic spatial-temporal disease dynamics,especially in scenarios where classical diffusion is insufficient.
基金supported by the National Natural Science Foundation of China(Nos.22379052,22479062 and 52102252)Taishan Scholars of Shandong Province(No.tsqnz20221143)Independent Cultivation Program of Innovation Team of Ji’nan City(No.202333042).
文摘The unique oxygen stacking sequence of O2-type structures restricts the irreversible transition metal movement into Li vacancies for the delithiated Li-rich layered oxides(LLOs)and maintains outstanding voltage stability.However,the ion-exchange synthesis promotes the Mn-ion valence reduction and aggravates the Jahn-Teller(J-T)distortion alongside disproportionation.Since the main oxidation state of the Mn ions is+4 in the traditional O3-type LLOs,synergistic effects of the O2-type and O3-type structures are expected in the O2/O3 diphasic Li-rich material.Herein,O2/O3 biphasic intergrowth LLOs were rationally designed,and the synergic optimization of the biphasic structure was planned to retard the J-T effect.The O2/O3 intergrowth nature was confirmed,and the percentages of the O2 and O3 phases were 56%and 44%,respectively.Density functional theory calculations demonstrated that the Mn^(2+)(EC)sheath had a remarkably lower energy barrier than the Li^(+)(EC)sheath.This finding suggests that Mn^(2+)ions that are dissolved into the electrolyte accelerate the electrolyte oxidization,so the deposition of the cathode electrolyte interface for pristine O2-LLOs causes a high electrochemical impedance.The designed O2/O3 biphasic LLOs boost the capacity stability and suppress the voltage drop upon repeated Li^(+)de-intercalation.The phase regulation strategy offers great potential for developing low-cost LLOs with enhanced structural stability for advanced Li-ion batteries.
基金financially supported by the China Postdoctoral Science Foundation(No.2024M751205)。
文摘Flexible phase change materials(PCMs)have become increasingly critical to address the demand for thermal management in electronic technologies and energy conversion.However,their application remains challenging because of their rigidity,liquid leakage,and insufficient thermal conductivity.Herein,flexible glutamic acid@natural rubber/paraffin wax(PW)/carbon nanotubes-graphene nanoplatelets(GNR/PW/CGNP)phase change composites with high thermal conductivity,excellent shape stability,and recyclability were reported.Zn^(2+)-based dynamic crosslinking was constructed through the reaction of zinc acetate and carboxyl groups on glutamic acid@natural rubber(GNR),which was used as a flexible matrix to physically blend with paraffin wax/carbon nanotubes/graphene nanoplatelets(PW/CGNP)to achieve uniform dispersion of PW/CGNP,continuous thermal conductivity networks,and good encapsulation of PW.The GNR/PW/CGNP composites showed excellent mechanical strength,flexibility,and recycling ability,and effective encapsulation prevented the outflow of melted PW during the phase transition.Also,the phase change enthalpy could attain 111.1 J/g with a higher thermal conductivity of 1.055 W/m K,428%higher than that of pure PW owing to the formation of efficient thermal conductive pathways,which exhibited outstanding thermal management performance and superior temperature control behavior in electronic devices.The developed flexible composite PCMs may open new possibilities for next-generation flexible thermal management electronics.
基金Supported by the Basic Product Innovation Plan for Vehicle Power Scientific Research Project(Grant No.JCCPCX201704).
文摘This research presents an advanced study on the modeling and stability analysis of electro-hydraulic control modules used in intelligent chassis systems.Firstly,a comprehensive nonlinear mathematical model of the electro-hydraulic power-shift system is developed,incorporating pipeline characteristics through impedance analysis and examining coupling effects between the pilot solenoid valve,main valve,and pipeline.Then,the model’s accuracy is validated through experimental testing,demonstrating high precision and minimal model errors.A comparative analysis between simulation data(both with and without pipeline characteristics)and experimental results reveals that the model considering pipeline parameters aligns more closely with experimental data,highlighting its superior accuracy.The research further explores the influence of key factors on system stability,including damping coefficient,feedback cavity orifice diameter,spring stiffness,pipeline length,and pipeline diameter.Significant findings include the critical impact of damping coefficient,orifice diameter,and pipeline length on stability,while spring stiffness has a minimal effect.These findings provide valuable insights for optimizing electro-hydraulic control modules in intelligent chassis systems,with practical implications for automotive and construction machinery applications.
