Silicon-air batteries(SABs),a new type of semiconductor air battery,have a high energy density.However,some side reactions in SABs cause Si anodes to be covered by a passivation layer to prevent continuous discharge,a...Silicon-air batteries(SABs),a new type of semiconductor air battery,have a high energy density.However,some side reactions in SABs cause Si anodes to be covered by a passivation layer to prevent continuous discharge,and the anode utilization rate is low.In this work,reduced graphene oxide(RGO)fabricated via high-temperature annealing or L-ascorbic acid(L.AA)reduction was first used to obtain Si nanowires/RGO-1000(Si NWs/RGO-1000)and Si nanowires/RGO-L.AA(Si NWs/RGO-L.AA)composite anodes for SABs.It was found that RGO suppressed the passivation and self-corrosion reactions and that SABs using Si NWs/RGO-L.AA as the anode can discharge for more than 700 h,breaking the previous performance of SABs,and that the specific capacity was increased by 90.8%compared to bare Si.This work provides a new solution for the design of high specific capacity SABs with nanostructures and anode protective layers.展开更多
Carbon-based foams with a three-dimensional structure can serve as a lightweight template for the rational design and control-lable preparation of metal oxide/carbon-based composite microwave absorption materials.In t...Carbon-based foams with a three-dimensional structure can serve as a lightweight template for the rational design and control-lable preparation of metal oxide/carbon-based composite microwave absorption materials.In this study,a flake-like nickel cobaltate/re-duced graphene oxide/melamine-derived carbon foam(FNC/RGO/MDCF)was successfully fabricated through a combination of solvo-thermal treatment and high-temperature pyrolysis.Results indicated that RGO was evenly distributed in the MDCF skeleton,providing ef-fective support for the load growth of FNC on its surface.Sample S3,the FNC/RGO/MDCF composite prepared by solvothermal method for 16 h,exhibited a minimum reflection loss(RL_(min))of-66.44 dB at a thickness of 2.29 mm.When the thickness was reduced to 1.50 mm,the optimal effective absorption bandwidth was 3.84 GHz.Analysis of the absorption mechanism of FNC/RGO/MDCF revealed that its excellent absorption performance was primarily attributed to the combined effects of conduction loss,multiple reflection,scattering,in-terface polarization,and dipole polarization.展开更多
In this manuscript,we propose an analytical equivalent linear viscoelastic constitutive model for fiber-reinforced composites,bypassing general computational homogenization.The method is based on the reduced-order hom...In this manuscript,we propose an analytical equivalent linear viscoelastic constitutive model for fiber-reinforced composites,bypassing general computational homogenization.The method is based on the reduced-order homogenization(ROH)approach.The ROH method typically involves solving multiple finite element problems under periodic conditions to evaluate elastic strain and eigenstrain influence functions in an‘off-line’stage,which offers substantial cost savings compared to direct computational homogenization methods.Due to the unique structure of the fibrous unit cell,“off-line”stage calculation can be eliminated by influence functions obtained analytically.Introducing the standard solid model to the ROH method enables the creation of a comprehensive analytical homogeneous viscoelastic constitutive model.This method treats fibrous composite materials as homogeneous,anisotropic viscoelastic materials,significantly reducing computational time due to its analytical nature.This approach also enables precise determination of a homogenized anisotropic relaxation modulus and accurate capture of various viscoelastic responses under different loading conditions.Three sets of numerical examples,including unit cell tests,three-point beam bending tests,and torsion tests,are given to demonstrate the predictive performance of the homogenized viscoelastic model.Furthermore,the model is validated against experimental measurements,confirming its accuracy and reliability.展开更多
This paper delves into the theoretical mechanisms of the electronic structure and optical properties of aluminum-based semiconductors(AlX,X=N,P,As,Sb)and indium-based semiconductors(InX,X=N,P,As,Sb)as potential materi...This paper delves into the theoretical mechanisms of the electronic structure and optical properties of aluminum-based semiconductors(AlX,X=N,P,As,Sb)and indium-based semiconductors(InX,X=N,P,As,Sb)as potential materials for optical devices.Band structure calculations reveal that,except for InSb,all other compounds are direct bandgap semiconductors,with AlN exhibiting a bandgap of 3.245 eV.The valence band maximum of these eight compounds primarily stems from the p-orbitals of Al/In and X.In contrast,the conduction band minimum is influenced by all orbitals,with a predominant contribution from the p-orbitals.The static dielectric constant increased with the expansion of the unit cell volume.Compared to AlX and InX with larger X atoms,AlN and InN showed broader absorption spectra in the near-ultraviolet region and higher photoelectric conductance.Regarding mechanical properties,AlN and InN displayed greater shear and bulk modulus than the other compounds.Moreover,among these eight crystal types,a higher modulus was associated with a lower light loss function value,indicating that AlN and InN have superior transmission efficiency and a wider spectral range in optoelectronic material applications.展开更多
We investigated the adsorption mechanisms including physical and chemical adsorption for heavy metals(Cd,Pb,Zn,Co,Cu)on C-lignin using density functional theory(DFT)simulations.Physical adsorption,involving metal atom...We investigated the adsorption mechanisms including physical and chemical adsorption for heavy metals(Cd,Pb,Zn,Co,Cu)on C-lignin using density functional theory(DFT)simulations.Physical adsorption,involving metal atoms near carbon atoms,is found to be endothermic;meanwhile,chemical adsorption,where hydroxyl groups replace metal ions,is exothermic and spontaneous.Pb exhibits the highest physical adsorption potential,while Cu and Co demonstrate the strongest chemical adsorption due to their highly negative adsorption energies.These findings provide valuable insights into the design of eco-friendly nano lignocellulosic composite films for effective heavy metal removal from contaminated water sources.Key words:C-lignin;adsorption;We investigated the adsorption mechanisms including physical and chemical adsorption for heavy metals(Cd,Pb,Zn,Co,Cu)on C-lignin using density functional theory(DFT)simulations.Physical adsorption,involving metal atoms near carbon atoms,is found to be endothermic;meanwhile,chemical adsorption,where hydroxyl groups replace metal ions,is exothermic and spontaneous.Pb exhibits the highest physical adsorption potential,while Cu and Co demonstrate the strongest chemical adsorption due to their highly negative adsorption energies.These findings provide valuable insights into the design of eco-friendly nano lignocellulosic composite films for effective heavy metal removal from contaminated water sources.展开更多
The eutrophication of rivers and lakes is becoming increasingly common,primarily because of pollution from agricultural non-point sources.We investigated the effects of optimized water and fertilizer treatments on agr...The eutrophication of rivers and lakes is becoming increasingly common,primarily because of pollution from agricultural non-point sources.We investigated the effects of optimized water and fertilizer treatments on agricultural non-point source pollution in the Nansi Lake basin.The water heat carbon nitrogen simulator model(WHCNS model)was used to analyze water and nitrogen transport in wheat fields in Nansi Lake basin.Four water and fertilizer treatments were set up:conventional fertilization and irrigation(CK),reduced controlled-release fertilizer and conventional irrigation(F2W1),an equal amount of controlled-release fertilizer and reduced irrigation(F1W2),and reduced controlled-release fertilizer and reduced irrigation(F2W2).The results indicated that the replacement of conventional fertilizers with controlled-release fertilizers,combined with reduced irrigation,led to reduced nitrogen loss.Compared with those of the CK,the cumulative nitrogen leaching and ammonia volatilization of F2W1 were reduced by 8.90 and 41.67%,respectively;under F1W2,the same parameters were reduced by 12.50 and 15.99%,respectively.Compared with the other treatments,F2W2 significantly reduced nitrogen loss while producing a stable yield.Compared with those of the CK,ammonia volatilization and nitrogen loss due to leaching were reduced by 29.17 and 27.13%,respectively,water and nitrogen use efficiencies increased by 11.38 and 17.80%,respectively.F2W2 showed the best performance among the treatments,considering water and fertilizer management.Our findings highlight the effectiveness of optimizing water and fertilizer application in improving the water and nitrogen use efficiency of wheat,which is of great significance for mitigating nitrogen loss from farmland in the Nansi Lake basin.展开更多
Over 70 years ago,China proposed the Five Principles of Peaceful Coexistence,which were first embraced by countries such as Myanmar and gradually gained traction across Asia.The Five Principles eventually became widel...Over 70 years ago,China proposed the Five Principles of Peaceful Coexistence,which were first embraced by countries such as Myanmar and gradually gained traction across Asia.The Five Principles eventually became widely recognized norms in international relations and foundational principles of international law,contributing significantly to the post-World War II international order.Decades on,the Five Principles have not faded into history.Rather,they have demonstrated renewed relevance in today’s complex global landscape.展开更多
TiO_(2)is a well-known photocatalyst with a band gap of 3.2 eV,yet its ability to absorb light is limited to the short wavelengths of ultraviolet light.To achieve a more effective photocatalytic material,we have desig...TiO_(2)is a well-known photocatalyst with a band gap of 3.2 eV,yet its ability to absorb light is limited to the short wavelengths of ultraviolet light.To achieve a more effective photocatalytic material,we have designed two-dimensional semiconductor TiOS materials using swarm intelligence algorithms combined with first-principles calculations.Three stable low-energy structures with space groups of P2_(1)/m,P3m1 and P2_(1)/c are identified.Among these structures,the Janus P3m1 phase is a direct bandgap semiconductor,while the P2_(1)/m and P2_(1)/c phases are indirect bandgap semiconductors.Utilizing the accurate hybrid density functional HSE06 method,the band gaps of the three structures are calculated to be 2.34 eV(P2_(1)/m),2.24 eV(P3m1)and 3.22 eV(P2_(1)/c).Optical calculations reveal that TiOS materials exhibit a good light-harvesting capability in both visible and ultraviolet spectral ranges.Moreover,the photocatalytic calculations also indicate that both P2_(1)/m and P3m1 TiOS can provide a strong driving force for converting H_(2)O to H_(2)and O_(2)in an acidic environment with pH=0.The structural stabilities,mechanical properties,electronic structures and hydrogen evolution reaction activities are also discussed in detail.Our research suggests that two-dimensional TiOS materials have potential applications in both semiconductor devices and photocatalysis.展开更多
The structural,relative stability,and electronic properties of two-dimensional AsP_(2)X_(6)(X=S,Se)were predicted and studied using the particle-swarm optimization method and first principles calculations.We proposed ...The structural,relative stability,and electronic properties of two-dimensional AsP_(2)X_(6)(X=S,Se)were predicted and studied using the particle-swarm optimization method and first principles calculations.We proposed two low energy structures with P312 and P-31m phases,both of which the structures are hexagonal in shape and show non-centrosymmetry for the P312 phase and centrosymmetry for the P-31m phase.According to our results,two structural phases are found to be stable thermally and dynamically.The P312 phase of AsP_(2)X_(6)(X=S,Se)are indirect semiconductors with band gaps of 2.44 eV(AsP2S6)and 2.18 eV(AsP2Se6)at the HSE06 level,and their absorption coefficients are predicted to reach the order of 10^(5)cm^(-1)from visible light to ultraviolet region,but the main absorption is manly in the ultraviolet region.The P-31m phase of AsP_(2)X_(6)(X=S,Se)exhibits metal character with the Fermi surface mainly occupied by the p orbital of S/Se.Remarkably,estimated by first principles calculations,the P-31m AsP2S6 is found to be an intrinsic phonon-mediated superconductor with a relatively high critical superconducting temperature of about 13.4 K,and the P-31m AsP2Se6 only has a superconducting temperature of 1.4 K,which suggest that the P-31m AsP2S6 may be a good candidate for a nanoscale superconductor.展开更多
Macroalgae dominate nutrient dynamics and function as high-value foods for microbial,meio-and macrofaunal communities in coastal ecosystems.Because of this vital role,it is important to clarify the physiological infor...Macroalgae dominate nutrient dynamics and function as high-value foods for microbial,meio-and macrofaunal communities in coastal ecosystems.Because of this vital role,it is important to clarify the physiological information associated with environmental changes as it reflects their growth potential.To evaluate the effects of the changes in salinity and nutrients,the photosynthetic efficiency of a green macroalga Ulva fasciata from the Daya Bay was tested at a range of salinity(i.e.,31 to 10 psu)and nitrogen content(i.e.,5 to 60μmol L^(-1)).The results showed that cellular chlorophyll a(Chl a),carbohydrate and protein contents of U.fasciata were increased due to reduced salinity,and were decreased by interactive nitrogen enrichment.Within a short culture period(i.e.,18 h),the reduced salinity decreased the maximum photosynthetic efficiency(rETRmax and Pmax)derived from the rapid light response curve and photosynthetic oxygen evolution rate versus irradiance curve,respectively,as well as the saturation irradiance(E_(K)).This reducing effect diminished with enlonged cultivation time and reversed to a stimulating effect after 24 h of cultivation.The nitrogen enrichment stimulated the rETRmax and Pmax,as well as the E_(K),regardless of salinity,especially within short-term cultivation period(i.e.,<24 h).In addition,our results indicate that seawater freshening lowers the photosynthetic efficiency of U.fasciata in the short term,which is mitigated by nitrogen enrichment,but stimulates it in the long term,providing insight into how macroalgae thrive in coastal or estuarine waters where salinity and nutrients normally covary strongly.展开更多
As the global exploration and development of oil and gas resources advances into deep formations,the harsh conditions of high temperature and high salinity present significant challenges for drilling fluids.In order t...As the global exploration and development of oil and gas resources advances into deep formations,the harsh conditions of high temperature and high salinity present significant challenges for drilling fluids.In order to address the technical difficulties associated with the failure of filtrate loss reducers under high-temperature and high-salinity conditions.In this study,a hydrophobic zwitterionic filtrate loss reducer(PDA)was synthesized based on N,N-dimethylacrylamide(DMAA),2-acrylamido-2-methylpropane sulfonic acid(AMPS),diallyl dimethyl ammonium chloride(DMDAAC),styrene(ST)and a specialty vinyl monomer(A1).When the concentration of PDA was 3%,the FLAPI of PDA-WBDF was 9.8 mL and the FLHTHP(180℃,3.5 MPa)was 37.8 mL after aging at 240℃for 16 h.In the saturated NaCl environment,the FLAPI of PDA-SWBDF was 4.0 mL and the FLHTHP(180℃,3.5 MPa)was 32.0 mL after aging at 220℃ for 16 h.Under high-temperature and high-salinity conditions,the combined effect of anti-polyelectrolyte and hydrophobic association allowed PDA to adsorb on the bentonite surface tightly.The sulfonic acid groups of PDA increased the negative electronegativity and the hydration film thickness on bentonite surface,which enhanced the colloidal stability,maintained the flattened lamellar structure of bentonite and formed an appropriate particle size distribution,resulting in the formation of dense mud cakes and reducing the filtration loss effectively.展开更多
Biodiesel is a clean and renewable energy,and it is an effective measure to optimize engine combustion fueled with biodiesel to meet the increasingly strict toxic and CO_(2) emission regulations of internal combustion...Biodiesel is a clean and renewable energy,and it is an effective measure to optimize engine combustion fueled with biodiesel to meet the increasingly strict toxic and CO_(2) emission regulations of internal combustion engines.A suitable-scale chemical kinetic mechanism is very crucial for the accurate and rapid prediction of engine combustion and emissions.However,most previous researchers developed the mechanism of blend fuels through the separate simplification and merging of the reduced mechanisms of diesel and biodiesel rather than considering their cross-reaction.In this study,a new reduced chemical reaction kinetics mechanism of diesel and biodiesel was constructed through the adoption of directed relationship graph (DRG),directed relationship graph with error propagation,and full-species sensitivity analysis (FSSA).N-heptane and methyl decanoate (MD) were selected as surrogates of traditional diesel and biodiesel,respectively.In this mechanism,the interactions between the intermediate products of both fuels were considered based on the cross-reaction theory.Reaction pathways were revealed,and the key species involved in the oxidation of n-heptane and MD were identified through sensitivity analyses.The reduced mechanism of n-heptane/MD consisting of 288 species and 800 reactions was developed and sufficiently verified by published experimental data.Prediction maps of ignition delay time were established at a wide range of parameter matrices (temperature from 600 to 1 700 K,pressure from 10 bar to 80 bar,equivalence ratio from 0.5 to 1.5) and different substitution ratios to identify the occurrence regions of the crossreaction.Concentration and sensitivity analyses were then conducted to further investigate the effects of cross-reactions.The results indicate temperature as the primary factor causing cross-reactivity.In addition,the reduced mechanism with cross-reactions was more accurate than that without cross-reactions.At 700–1 000 K,the cross-reactions inhibited the consumption of n-heptane/MD,which resulted in a prolonged ignition delay time.At this point,the elementary reaction,NC_(7)H_(16)+OH<=>C_(7)H_(15)-2+H_(2)O,played a dominant role in fuel consumption.Specifically,the contribution of the MD consumption reaction to ignition decreased,and the increased generation time of OH,HO_(2),and H_(2)O_(2) was directly responsible for the increased ignition delay.展开更多
The relative permeability of oil and water is a key factor in assessing the production performance of a reservoir.This study analyzed the impact of injecting a viscosity reducer solution into low-viscosity crude oil t...The relative permeability of oil and water is a key factor in assessing the production performance of a reservoir.This study analyzed the impact of injecting a viscosity reducer solution into low-viscosity crude oil to enhance fluid flow within a low-permeability reservoir.At 72°C,the oil-water dispersion solution achieved a viscosity reduction rate(f)of 92.42%,formulated with a viscosity reducer agent concentration(C_(VR))of 0.1%and an oil-water ratio of 5:5.The interfacial tension between the viscosity reducer solution and the crude oil remained stable at approximately 1.0 mN/m across different concentrations,with the minimum value of 4.07×10^(-1)mN/m recorded at a C_(VR)of 0.2%.As the CVR increased,the relative permeability curve of the oil phase gradually decreased while the oil-water two-phase region(Ro-wtp)expanded significantly.At a C_(VR)of 0.1%,the R_(o-wtp)peaked,making an increase of 7.93 percentage points compared to water flooding.In addition,the final displacement efficiency(E_(R),final)achieved with a 0.1%viscosity reducer solution reached 48.64%,exceeding water flooding by 15.46 percentage points,highlighting the effectiveness of the viscosity reducer solution in enhancing oil recovery.展开更多
Gold-platinum(Au-Pt)alloy has aroused considerable attention due to its ultra-low magnetic susceptibility(MS)in testing mass(TM)on spacecraft.However,the effect of Au content on the properties of the alloy has not yet...Gold-platinum(Au-Pt)alloy has aroused considerable attention due to its ultra-low magnetic susceptibility(MS)in testing mass(TM)on spacecraft.However,the effect of Au content on the properties of the alloy has not yet been understood.In this study,the composition design of Au-Pt alloy with ultra-low MS was achieved through density functional theory(DFT)and experimental methods.The elastic,thermal properties and electronic structure were systematically investigated,the composition range was further optimized and Au75Pt25 was determined to be the most suitable alloy for TM material.The phase composition of this alloy after cold rolling and solid solution was characterized,indicating a single-phase FCC structure.In addition,there is a good validation between the experimental Vickers hardness and the DFT results.This work provides new insights into the compositional optimization of Au-Pt alloys and lays the foundation for alloy development.展开更多
The demand for anisotropic aerogels with excellent comprehensive properties in cutting-edge fields such as aerospace is growing.Based on the above background,a novel heterocyclic para-aramid nanofiber/reduced graphene...The demand for anisotropic aerogels with excellent comprehensive properties in cutting-edge fields such as aerospace is growing.Based on the above background,a novel heterocyclic para-aramid nanofiber/reduced graphene oxide(HPAN/rGO)composite aerogel was prepared by combining electrospinning and unidirectional freeze-drying.The anisotropic HPAN/rGO composite aerogel exhibited a honeycomb morphology in the direction perpendicular to the growth of ice crystals,and a through-well structure of directed microchannels in the direction parallel to the temperature gradient.By varying the mass ratio of HPAN/rGO,a composite aerogel with an ultra-low density of 5.34-7.81 mg·cm^(-3) and an ultra-high porosity of 98%-99%was obtained.Benefiting from the anisotropic structure,the radial and axial thermal conductivities of HPAN/rGO-3 composite aerogel were 29.37 and 44.35 mW·m^(-1)·K^(-1),respectively.A combination of software simulation and experiments was used to analyze the effect of anisotropic structures on the thermal insulation properties of aerogels.Moreover,due to the intrinsic self-extinguishing properties of heterocyclic para-aramid and the protection of the graphene carbon layer,the composite aerogel also exhibits excellent flame retardancy properties,and its total heat release rate(THR)was only 5.8 kJ·g^(-1),which is far superior to many reported aerogels.Therefore,ultralight anisotropic HPAN/rGO composite aerogels with excellent high-temperature thermal insulation and flame retardancy properties have broad application prospects in complex environments such as aerospace.展开更多
Fast electron-hole recombination issues during titanium dioxide(TiO_(2))photocatalysis limit its application in preventing bacterial infection during bone defect repair.In this study,TiO_(2)@reduced graphene oxide(rGO...Fast electron-hole recombination issues during titanium dioxide(TiO_(2))photocatalysis limit its application in preventing bacterial infection during bone defect repair.In this study,TiO_(2)@reduced graphene oxide(rGO)composites were synthesized using a hydrothermal method in which rGO,which possesses very high electrical conductivity,promotes the separation of photoelectron-hole pairs of TiO_(2),thus improving the efficiency of photocatalytic production of reactive oxygen species(ROS).Subsequently,TiO_(2)@rGO composites were introduced into poly-L-lactic acid(PLLA)to prepare bone scaffolds with photocatalytic antibacterial function via selective laser sintering.The results showed that TiO_(2)grew on the surface of rGO and formed a covalent bond connection(Ti-O-C)with rGO.A decreased electrochemical impedance of TiO_(2)@rGO composites was observed,and the transient photocurrent intensity increased from 0.05 to 0.5μA/cm^(2).Analysis of electron spin resonance found that the photocatalytic products of TiO_(2)were·OH and·O^(2-),two kinds of ROS capable of killing bacteria via disrupting the structure of the bacterial membrane in vitro.Antibacterial experiments showed that the PLLA/TiO_(2)@rGO scaffolds had good antibacterial properties against Escherichia coli and Staphylococcus aureus.Finally,we report that these scaffolds exhibited both enhanced mechanical properties due to the addition of TiO_(2)@rGO as a reinforcement material and good biocompatibility during cell proliferation.展开更多
A critical challenge for global food security and sustainable agriculture is enhancing crop yields while reducing chemical N inputs.Improving N use efficiency in crops is essential for increasing agricultural producti...A critical challenge for global food security and sustainable agriculture is enhancing crop yields while reducing chemical N inputs.Improving N use efficiency in crops is essential for increasing agricultural productivity.The aim of this study was to evaluate the impacts of intercropping maize with leguminous green manure on grain yield and N utilization under reduced N-fertilization conditions.A field experiment with a split-plot design was conducted in northwestern China from 2018 to 2021.The main plots consisted of two cropping systems:maize-common vetch intercropping(IM)and sole maize(SM).The subplots had three N levels:zero N application(N0,0 kg ha^(-1)),a 25%reduction from the traditional chemical N supply(N1,270 kg ha^(-1)),and the traditional chemical N supply(N2,360 kg ha^(-1)).The results showed that the negative effects of N reduction on maize grain yield and N uptake were compensated by intercropping leguminous green manure,and the improvements increased with cultivation years.The integrated system involving maize-leguminous green manure intercropping and a reduced N supply enhanced N translocation from maize vegetative organs to grains and increased the nitrate reductase and glutamine synthetase activities in maize leaves.The supercompensatory effect in maize leaves increased year by year,reaching values of 16.1,21.3,and 25.5%in 2019,2020,and 2021,respectively.These findings suggest that intercropping maize with leguminous green manure under reduced chemical N input can enhance N assimilation and uptake in maize.By using this strategy,chemical fertilizer is effectively replaced by leguminous green manure,thereby improving N use efficiency and maintaining stable yields in the maize-based intercropping system.展开更多
Thermal Protection System(TPS)with thick tiles,low thermal conductivity,and a short re-entry stage stands as a critical element within reusable aircraft,whose reliability is related to the function and changes with th...Thermal Protection System(TPS)with thick tiles,low thermal conductivity,and a short re-entry stage stands as a critical element within reusable aircraft,whose reliability is related to the function and changes with their physical properties,external conditions,and degradation.Meanwhile,due to the limitation of testing resources,epistemic uncertainties stemming from the small samples are present in TPS reliability modeling.However,current TPS reliability modeling methods face challenges in characterizing the relationships among reliability and physical properties,external conditions,degradation,and epistemic uncertainties.Therefore,under the framework of belief reliability theory,a TPS reliability model is constructed,which takes into account the physical principle,external conditions,performance degradation,and epistemic uncertainties.A reliability simulation algorithm is proposed to calculate TPS reliability.Through a case study and comparison analysis,the proposed method is validated as more effective than the existing method.Additionally,reliability sensitivity analysis is conducted to identify the sensitive factors of reliability under the condition of small samples,through which suggestions are provided for TPS functional design and improvement.展开更多
Rechargeable batteries are essential energy storage devices that power portable devices and electrical vehicles throughout the wo rld.In general,it is thought that the electrochemical performance of recha rgeable batt...Rechargeable batteries are essential energy storage devices that power portable devices and electrical vehicles throughout the wo rld.In general,it is thought that the electrochemical performance of recha rgeable batteries is mostly determined by the electrodes within them and that the electrolyte plays a relatively passive role.However,ion transport and storage can be greatly influenced by the electrolyte solution structure,specifically,ion solvation within the bulk and ion desolvation across the electrode/electrolyte interfaces.Herein,we studied the role of the electrolyte as an active component of electrochemical energy storage devices.We found that with an appropriate electrolyte formulation,ion storage in disordered carbonaceous anode materials can occur spontaneously without externally supplied electrical energy.Reduced graphene oxide(RGO)in an ether-based electrolyte demonstrates'spontaneous'ion storage behaviors of adsorbing and inserting the solvated ions utilizing facilitated permeability and wettability of RGO,which results in Coulombic efficiency of~145%due to additional charging capacity of~180 mAh g^(-1)during electrochemical processes.The unexpected spontaneous ion storage behavior was extensively investigated using a combination of electrochemical analyses and diagnostics,advanced characterizations,and computational simulation.We believe the spontaneous ion storage behavior offers a new way to further improve the energy efficiency of practical rechargeable batteries.展开更多
The present work investigates the microstructural evolution and mechanical properties in a novel medium-Si 12%Cr reduced activation ferritic/martensitic steel cladding tube(Fe-11.8Cr-0.2C-1.4W-0.17Ta-0.2V-0.55Si-0.5Mn...The present work investigates the microstructural evolution and mechanical properties in a novel medium-Si 12%Cr reduced activation ferritic/martensitic steel cladding tube(Fe-11.8Cr-0.2C-1.4W-0.17Ta-0.2V-0.55Si-0.5Mn,wt%)during multipass cold rolling and annealing.The initial hot-extruded tube exhibited a full martensitic matrix with the prior austenite grain size of~32μm.After annealing,Cr_(23)C_(6) and TaC particles were precipitated,which are basically unchanged(152-183 nm and 84-113 nm,respectively)during the manufacturing process.Meanwhile,with the cold-rolling strain(ε)increasing and subsequent annealing,the martensitic lath gradually diminishes,and the recrystallization volume fraction(f_(r))is increased.Based on the static recrystallization kinetics model,a clear relationship between f_(r) andεis established,in which the newly proposed kinetic equation demonstrates a strong correlation with the experimental results.Furthermore,the yield strength(σ_(YS)=362 MPa)of the final annealed state was much lower than that(σ_(YS)=482 MPa)of the initial annealed state,which can be attributed to the recrystallization from the martensitic matrix to ferritic matrix.Various strengthening mechanisms are further discussed,and the calculated strengths are in good agreement with the experimental results.This work provides a guidance for the optimization of cold-rolling and annealing treatments in the manufacture of cladding tube.展开更多
基金supported by the National Natural Science Foundation of China(No.61904073)Spring City Plan-Special Program for Young Talents(No.K202005007)+4 种基金Yunnan Talents Support Plan for Yong Talents(No.XDYC-QNRC-20220482)Yunnan Local Colleges Applied Basic Research Projects(No.202101BA070001-138)Scientific Research Fund of Yunnan Education Department(No.2023Y0883)Frontier Research Team of Kunming University 2023Key Laboratory of Artificial Microstructures in Yunnan Higher Education。
文摘Silicon-air batteries(SABs),a new type of semiconductor air battery,have a high energy density.However,some side reactions in SABs cause Si anodes to be covered by a passivation layer to prevent continuous discharge,and the anode utilization rate is low.In this work,reduced graphene oxide(RGO)fabricated via high-temperature annealing or L-ascorbic acid(L.AA)reduction was first used to obtain Si nanowires/RGO-1000(Si NWs/RGO-1000)and Si nanowires/RGO-L.AA(Si NWs/RGO-L.AA)composite anodes for SABs.It was found that RGO suppressed the passivation and self-corrosion reactions and that SABs using Si NWs/RGO-L.AA as the anode can discharge for more than 700 h,breaking the previous performance of SABs,and that the specific capacity was increased by 90.8%compared to bare Si.This work provides a new solution for the design of high specific capacity SABs with nanostructures and anode protective layers.
基金support of the Key Science Research Project in Colleges and Universities of Anhui Province,China(No.2022AH050813)the Medical Special Cultivation Project of Anhui University of Science and Technology,China(No.YZ2023H2A002).
文摘Carbon-based foams with a three-dimensional structure can serve as a lightweight template for the rational design and control-lable preparation of metal oxide/carbon-based composite microwave absorption materials.In this study,a flake-like nickel cobaltate/re-duced graphene oxide/melamine-derived carbon foam(FNC/RGO/MDCF)was successfully fabricated through a combination of solvo-thermal treatment and high-temperature pyrolysis.Results indicated that RGO was evenly distributed in the MDCF skeleton,providing ef-fective support for the load growth of FNC on its surface.Sample S3,the FNC/RGO/MDCF composite prepared by solvothermal method for 16 h,exhibited a minimum reflection loss(RL_(min))of-66.44 dB at a thickness of 2.29 mm.When the thickness was reduced to 1.50 mm,the optimal effective absorption bandwidth was 3.84 GHz.Analysis of the absorption mechanism of FNC/RGO/MDCF revealed that its excellent absorption performance was primarily attributed to the combined effects of conduction loss,multiple reflection,scattering,in-terface polarization,and dipole polarization.
基金support by the National Key R&D Program of China(Grant No.2023YFA1008901)the National Natural Science Foundation of China(Grant Nos.11988102,12172009)is gratefully acknowledged.
文摘In this manuscript,we propose an analytical equivalent linear viscoelastic constitutive model for fiber-reinforced composites,bypassing general computational homogenization.The method is based on the reduced-order homogenization(ROH)approach.The ROH method typically involves solving multiple finite element problems under periodic conditions to evaluate elastic strain and eigenstrain influence functions in an‘off-line’stage,which offers substantial cost savings compared to direct computational homogenization methods.Due to the unique structure of the fibrous unit cell,“off-line”stage calculation can be eliminated by influence functions obtained analytically.Introducing the standard solid model to the ROH method enables the creation of a comprehensive analytical homogeneous viscoelastic constitutive model.This method treats fibrous composite materials as homogeneous,anisotropic viscoelastic materials,significantly reducing computational time due to its analytical nature.This approach also enables precise determination of a homogenized anisotropic relaxation modulus and accurate capture of various viscoelastic responses under different loading conditions.Three sets of numerical examples,including unit cell tests,three-point beam bending tests,and torsion tests,are given to demonstrate the predictive performance of the homogenized viscoelastic model.Furthermore,the model is validated against experimental measurements,confirming its accuracy and reliability.
文摘This paper delves into the theoretical mechanisms of the electronic structure and optical properties of aluminum-based semiconductors(AlX,X=N,P,As,Sb)and indium-based semiconductors(InX,X=N,P,As,Sb)as potential materials for optical devices.Band structure calculations reveal that,except for InSb,all other compounds are direct bandgap semiconductors,with AlN exhibiting a bandgap of 3.245 eV.The valence band maximum of these eight compounds primarily stems from the p-orbitals of Al/In and X.In contrast,the conduction band minimum is influenced by all orbitals,with a predominant contribution from the p-orbitals.The static dielectric constant increased with the expansion of the unit cell volume.Compared to AlX and InX with larger X atoms,AlN and InN showed broader absorption spectra in the near-ultraviolet region and higher photoelectric conductance.Regarding mechanical properties,AlN and InN displayed greater shear and bulk modulus than the other compounds.Moreover,among these eight crystal types,a higher modulus was associated with a lower light loss function value,indicating that AlN and InN have superior transmission efficiency and a wider spectral range in optoelectronic material applications.
基金Funded by the Hubei Province Key Research Foundation for Water Resources,China(No.HBSLKY2023035)the National College Students’Innovation and Entrepreneurship Training Program,China(No.202310500012)the Wuhan Talents Outstanding Young Talents Program。
文摘We investigated the adsorption mechanisms including physical and chemical adsorption for heavy metals(Cd,Pb,Zn,Co,Cu)on C-lignin using density functional theory(DFT)simulations.Physical adsorption,involving metal atoms near carbon atoms,is found to be endothermic;meanwhile,chemical adsorption,where hydroxyl groups replace metal ions,is exothermic and spontaneous.Pb exhibits the highest physical adsorption potential,while Cu and Co demonstrate the strongest chemical adsorption due to their highly negative adsorption energies.These findings provide valuable insights into the design of eco-friendly nano lignocellulosic composite films for effective heavy metal removal from contaminated water sources.Key words:C-lignin;adsorption;We investigated the adsorption mechanisms including physical and chemical adsorption for heavy metals(Cd,Pb,Zn,Co,Cu)on C-lignin using density functional theory(DFT)simulations.Physical adsorption,involving metal atoms near carbon atoms,is found to be endothermic;meanwhile,chemical adsorption,where hydroxyl groups replace metal ions,is exothermic and spontaneous.Pb exhibits the highest physical adsorption potential,while Cu and Co demonstrate the strongest chemical adsorption due to their highly negative adsorption energies.These findings provide valuable insights into the design of eco-friendly nano lignocellulosic composite films for effective heavy metal removal from contaminated water sources.
基金supported by the National Key Research and Development Program of China(2018YFD0800303)the Major Science and Technology Innovation Projects in Shandong Province,China(2021CXGC010804).
文摘The eutrophication of rivers and lakes is becoming increasingly common,primarily because of pollution from agricultural non-point sources.We investigated the effects of optimized water and fertilizer treatments on agricultural non-point source pollution in the Nansi Lake basin.The water heat carbon nitrogen simulator model(WHCNS model)was used to analyze water and nitrogen transport in wheat fields in Nansi Lake basin.Four water and fertilizer treatments were set up:conventional fertilization and irrigation(CK),reduced controlled-release fertilizer and conventional irrigation(F2W1),an equal amount of controlled-release fertilizer and reduced irrigation(F1W2),and reduced controlled-release fertilizer and reduced irrigation(F2W2).The results indicated that the replacement of conventional fertilizers with controlled-release fertilizers,combined with reduced irrigation,led to reduced nitrogen loss.Compared with those of the CK,the cumulative nitrogen leaching and ammonia volatilization of F2W1 were reduced by 8.90 and 41.67%,respectively;under F1W2,the same parameters were reduced by 12.50 and 15.99%,respectively.Compared with the other treatments,F2W2 significantly reduced nitrogen loss while producing a stable yield.Compared with those of the CK,ammonia volatilization and nitrogen loss due to leaching were reduced by 29.17 and 27.13%,respectively,water and nitrogen use efficiencies increased by 11.38 and 17.80%,respectively.F2W2 showed the best performance among the treatments,considering water and fertilizer management.Our findings highlight the effectiveness of optimizing water and fertilizer application in improving the water and nitrogen use efficiency of wheat,which is of great significance for mitigating nitrogen loss from farmland in the Nansi Lake basin.
基金phased achievement of the Yunnan Provincial Philosophy and Social Sciences Innovation Team project titled Research on Ethnic Issues and Their Impact in Northern Myanmar(No.2025CX09).
文摘Over 70 years ago,China proposed the Five Principles of Peaceful Coexistence,which were first embraced by countries such as Myanmar and gradually gained traction across Asia.The Five Principles eventually became widely recognized norms in international relations and foundational principles of international law,contributing significantly to the post-World War II international order.Decades on,the Five Principles have not faded into history.Rather,they have demonstrated renewed relevance in today’s complex global landscape.
基金supported by the National Natural Science Foundation of China(Grant Nos.52272219 and U1904612)the Natural Science Foundation of Henan Province(Grant No.242300421191).
文摘TiO_(2)is a well-known photocatalyst with a band gap of 3.2 eV,yet its ability to absorb light is limited to the short wavelengths of ultraviolet light.To achieve a more effective photocatalytic material,we have designed two-dimensional semiconductor TiOS materials using swarm intelligence algorithms combined with first-principles calculations.Three stable low-energy structures with space groups of P2_(1)/m,P3m1 and P2_(1)/c are identified.Among these structures,the Janus P3m1 phase is a direct bandgap semiconductor,while the P2_(1)/m and P2_(1)/c phases are indirect bandgap semiconductors.Utilizing the accurate hybrid density functional HSE06 method,the band gaps of the three structures are calculated to be 2.34 eV(P2_(1)/m),2.24 eV(P3m1)and 3.22 eV(P2_(1)/c).Optical calculations reveal that TiOS materials exhibit a good light-harvesting capability in both visible and ultraviolet spectral ranges.Moreover,the photocatalytic calculations also indicate that both P2_(1)/m and P3m1 TiOS can provide a strong driving force for converting H_(2)O to H_(2)and O_(2)in an acidic environment with pH=0.The structural stabilities,mechanical properties,electronic structures and hydrogen evolution reaction activities are also discussed in detail.Our research suggests that two-dimensional TiOS materials have potential applications in both semiconductor devices and photocatalysis.
基金Funded by the National Natural Science Foundation of China(No.U1904612)the Natural Science Foundation of Henan Province(No.222300420506)。
文摘The structural,relative stability,and electronic properties of two-dimensional AsP_(2)X_(6)(X=S,Se)were predicted and studied using the particle-swarm optimization method and first principles calculations.We proposed two low energy structures with P312 and P-31m phases,both of which the structures are hexagonal in shape and show non-centrosymmetry for the P312 phase and centrosymmetry for the P-31m phase.According to our results,two structural phases are found to be stable thermally and dynamically.The P312 phase of AsP_(2)X_(6)(X=S,Se)are indirect semiconductors with band gaps of 2.44 eV(AsP2S6)and 2.18 eV(AsP2Se6)at the HSE06 level,and their absorption coefficients are predicted to reach the order of 10^(5)cm^(-1)from visible light to ultraviolet region,but the main absorption is manly in the ultraviolet region.The P-31m phase of AsP_(2)X_(6)(X=S,Se)exhibits metal character with the Fermi surface mainly occupied by the p orbital of S/Se.Remarkably,estimated by first principles calculations,the P-31m AsP2S6 is found to be an intrinsic phonon-mediated superconductor with a relatively high critical superconducting temperature of about 13.4 K,and the P-31m AsP2Se6 only has a superconducting temperature of 1.4 K,which suggest that the P-31m AsP2S6 may be a good candidate for a nanoscale superconductor.
基金funded by the National Key Research and Development Program of China(No.20022YFC3102405)the National Natural Science Foundation of China(Nos.42425004,32371665)the Natural Science Foundation of Guangdong Province(Nos.2022A1515011461,2022A1515011831)。
文摘Macroalgae dominate nutrient dynamics and function as high-value foods for microbial,meio-and macrofaunal communities in coastal ecosystems.Because of this vital role,it is important to clarify the physiological information associated with environmental changes as it reflects their growth potential.To evaluate the effects of the changes in salinity and nutrients,the photosynthetic efficiency of a green macroalga Ulva fasciata from the Daya Bay was tested at a range of salinity(i.e.,31 to 10 psu)and nitrogen content(i.e.,5 to 60μmol L^(-1)).The results showed that cellular chlorophyll a(Chl a),carbohydrate and protein contents of U.fasciata were increased due to reduced salinity,and were decreased by interactive nitrogen enrichment.Within a short culture period(i.e.,18 h),the reduced salinity decreased the maximum photosynthetic efficiency(rETRmax and Pmax)derived from the rapid light response curve and photosynthetic oxygen evolution rate versus irradiance curve,respectively,as well as the saturation irradiance(E_(K)).This reducing effect diminished with enlonged cultivation time and reversed to a stimulating effect after 24 h of cultivation.The nitrogen enrichment stimulated the rETRmax and Pmax,as well as the E_(K),regardless of salinity,especially within short-term cultivation period(i.e.,<24 h).In addition,our results indicate that seawater freshening lowers the photosynthetic efficiency of U.fasciata in the short term,which is mitigated by nitrogen enrichment,but stimulates it in the long term,providing insight into how macroalgae thrive in coastal or estuarine waters where salinity and nutrients normally covary strongly.
基金supported by State Key Laboratory of Deep Oil and Gas(No.SKLDOG2024-ZYRC-03)supported by the Excellent Young Scientists Fund of the National Natural Science Foundation of China(No.52322401)the National Natural Science Foundation of China(52288101).
文摘As the global exploration and development of oil and gas resources advances into deep formations,the harsh conditions of high temperature and high salinity present significant challenges for drilling fluids.In order to address the technical difficulties associated with the failure of filtrate loss reducers under high-temperature and high-salinity conditions.In this study,a hydrophobic zwitterionic filtrate loss reducer(PDA)was synthesized based on N,N-dimethylacrylamide(DMAA),2-acrylamido-2-methylpropane sulfonic acid(AMPS),diallyl dimethyl ammonium chloride(DMDAAC),styrene(ST)and a specialty vinyl monomer(A1).When the concentration of PDA was 3%,the FLAPI of PDA-WBDF was 9.8 mL and the FLHTHP(180℃,3.5 MPa)was 37.8 mL after aging at 240℃for 16 h.In the saturated NaCl environment,the FLAPI of PDA-SWBDF was 4.0 mL and the FLHTHP(180℃,3.5 MPa)was 32.0 mL after aging at 220℃ for 16 h.Under high-temperature and high-salinity conditions,the combined effect of anti-polyelectrolyte and hydrophobic association allowed PDA to adsorb on the bentonite surface tightly.The sulfonic acid groups of PDA increased the negative electronegativity and the hydration film thickness on bentonite surface,which enhanced the colloidal stability,maintained the flattened lamellar structure of bentonite and formed an appropriate particle size distribution,resulting in the formation of dense mud cakes and reducing the filtration loss effectively.
基金Supported by the National Natural Science Foundation of China (Grant No. 52171298)the National Foreign Experts Program (G2023180006L)+1 种基金the Natural Science Foundation of Heilongjiang Province of China (Grant No. ZD2019E003)the Fundamental Research Funds for the Central Universities (Grant No. 3072022TS0303)。
文摘Biodiesel is a clean and renewable energy,and it is an effective measure to optimize engine combustion fueled with biodiesel to meet the increasingly strict toxic and CO_(2) emission regulations of internal combustion engines.A suitable-scale chemical kinetic mechanism is very crucial for the accurate and rapid prediction of engine combustion and emissions.However,most previous researchers developed the mechanism of blend fuels through the separate simplification and merging of the reduced mechanisms of diesel and biodiesel rather than considering their cross-reaction.In this study,a new reduced chemical reaction kinetics mechanism of diesel and biodiesel was constructed through the adoption of directed relationship graph (DRG),directed relationship graph with error propagation,and full-species sensitivity analysis (FSSA).N-heptane and methyl decanoate (MD) were selected as surrogates of traditional diesel and biodiesel,respectively.In this mechanism,the interactions between the intermediate products of both fuels were considered based on the cross-reaction theory.Reaction pathways were revealed,and the key species involved in the oxidation of n-heptane and MD were identified through sensitivity analyses.The reduced mechanism of n-heptane/MD consisting of 288 species and 800 reactions was developed and sufficiently verified by published experimental data.Prediction maps of ignition delay time were established at a wide range of parameter matrices (temperature from 600 to 1 700 K,pressure from 10 bar to 80 bar,equivalence ratio from 0.5 to 1.5) and different substitution ratios to identify the occurrence regions of the crossreaction.Concentration and sensitivity analyses were then conducted to further investigate the effects of cross-reactions.The results indicate temperature as the primary factor causing cross-reactivity.In addition,the reduced mechanism with cross-reactions was more accurate than that without cross-reactions.At 700–1 000 K,the cross-reactions inhibited the consumption of n-heptane/MD,which resulted in a prolonged ignition delay time.At this point,the elementary reaction,NC_(7)H_(16)+OH<=>C_(7)H_(15)-2+H_(2)O,played a dominant role in fuel consumption.Specifically,the contribution of the MD consumption reaction to ignition decreased,and the increased generation time of OH,HO_(2),and H_(2)O_(2) was directly responsible for the increased ignition delay.
基金supported by the Petrochina Daqing Oilfield Research Project(No.DQYT-1201002-2023-JS-1201).
文摘The relative permeability of oil and water is a key factor in assessing the production performance of a reservoir.This study analyzed the impact of injecting a viscosity reducer solution into low-viscosity crude oil to enhance fluid flow within a low-permeability reservoir.At 72°C,the oil-water dispersion solution achieved a viscosity reduction rate(f)of 92.42%,formulated with a viscosity reducer agent concentration(C_(VR))of 0.1%and an oil-water ratio of 5:5.The interfacial tension between the viscosity reducer solution and the crude oil remained stable at approximately 1.0 mN/m across different concentrations,with the minimum value of 4.07×10^(-1)mN/m recorded at a C_(VR)of 0.2%.As the CVR increased,the relative permeability curve of the oil phase gradually decreased while the oil-water two-phase region(Ro-wtp)expanded significantly.At a C_(VR)of 0.1%,the R_(o-wtp)peaked,making an increase of 7.93 percentage points compared to water flooding.In addition,the final displacement efficiency(E_(R),final)achieved with a 0.1%viscosity reducer solution reached 48.64%,exceeding water flooding by 15.46 percentage points,highlighting the effectiveness of the viscosity reducer solution in enhancing oil recovery.
基金financially supported by the National Key R&D Program of China(No.2021YFC2202300)the National Natural Science Foundation of China(NSFC)(No.51974258)the National College Students Innovation and Entrepreneurship Training Program(No.S202210699134).
文摘Gold-platinum(Au-Pt)alloy has aroused considerable attention due to its ultra-low magnetic susceptibility(MS)in testing mass(TM)on spacecraft.However,the effect of Au content on the properties of the alloy has not yet been understood.In this study,the composition design of Au-Pt alloy with ultra-low MS was achieved through density functional theory(DFT)and experimental methods.The elastic,thermal properties and electronic structure were systematically investigated,the composition range was further optimized and Au75Pt25 was determined to be the most suitable alloy for TM material.The phase composition of this alloy after cold rolling and solid solution was characterized,indicating a single-phase FCC structure.In addition,there is a good validation between the experimental Vickers hardness and the DFT results.This work provides new insights into the compositional optimization of Au-Pt alloys and lays the foundation for alloy development.
基金supported by the National Key R&D Program of China(No.2021YFB3700103).
文摘The demand for anisotropic aerogels with excellent comprehensive properties in cutting-edge fields such as aerospace is growing.Based on the above background,a novel heterocyclic para-aramid nanofiber/reduced graphene oxide(HPAN/rGO)composite aerogel was prepared by combining electrospinning and unidirectional freeze-drying.The anisotropic HPAN/rGO composite aerogel exhibited a honeycomb morphology in the direction perpendicular to the growth of ice crystals,and a through-well structure of directed microchannels in the direction parallel to the temperature gradient.By varying the mass ratio of HPAN/rGO,a composite aerogel with an ultra-low density of 5.34-7.81 mg·cm^(-3) and an ultra-high porosity of 98%-99%was obtained.Benefiting from the anisotropic structure,the radial and axial thermal conductivities of HPAN/rGO-3 composite aerogel were 29.37 and 44.35 mW·m^(-1)·K^(-1),respectively.A combination of software simulation and experiments was used to analyze the effect of anisotropic structures on the thermal insulation properties of aerogels.Moreover,due to the intrinsic self-extinguishing properties of heterocyclic para-aramid and the protection of the graphene carbon layer,the composite aerogel also exhibits excellent flame retardancy properties,and its total heat release rate(THR)was only 5.8 kJ·g^(-1),which is far superior to many reported aerogels.Therefore,ultralight anisotropic HPAN/rGO composite aerogels with excellent high-temperature thermal insulation and flame retardancy properties have broad application prospects in complex environments such as aerospace.
基金supported by the following funds:The National Natural Science Foundation of China(Nos.52275393,51935014,and 82072084)Jiangxi Provincial Natural Science Foundation of China(No.20224ACB204013)+2 种基金The Project of State Key Laboratory of Precision Manufacturing for Extreme Service Performancethe National Key Research and Development Program of China(No.2023YFB4605800)the Independent Exploration and Innovation Project of Central South University(No.1053320221707).
文摘Fast electron-hole recombination issues during titanium dioxide(TiO_(2))photocatalysis limit its application in preventing bacterial infection during bone defect repair.In this study,TiO_(2)@reduced graphene oxide(rGO)composites were synthesized using a hydrothermal method in which rGO,which possesses very high electrical conductivity,promotes the separation of photoelectron-hole pairs of TiO_(2),thus improving the efficiency of photocatalytic production of reactive oxygen species(ROS).Subsequently,TiO_(2)@rGO composites were introduced into poly-L-lactic acid(PLLA)to prepare bone scaffolds with photocatalytic antibacterial function via selective laser sintering.The results showed that TiO_(2)grew on the surface of rGO and formed a covalent bond connection(Ti-O-C)with rGO.A decreased electrochemical impedance of TiO_(2)@rGO composites was observed,and the transient photocurrent intensity increased from 0.05 to 0.5μA/cm^(2).Analysis of electron spin resonance found that the photocatalytic products of TiO_(2)were·OH and·O^(2-),two kinds of ROS capable of killing bacteria via disrupting the structure of the bacterial membrane in vitro.Antibacterial experiments showed that the PLLA/TiO_(2)@rGO scaffolds had good antibacterial properties against Escherichia coli and Staphylococcus aureus.Finally,we report that these scaffolds exhibited both enhanced mechanical properties due to the addition of TiO_(2)@rGO as a reinforcement material and good biocompatibility during cell proliferation.
基金supported by the‘Double First-Class’Key Scientific Research Project of Education Department in Gansu Province,China(GSSYLXM-02)the National Natural Science Foundation of China(U21A20218 and 32160765)+3 种基金the earmarked fund for China Agriculture Research System(CARS-22-G-12)the Science and Technology Project of Gansu Province,China(20JR5RA037 and 21JR7RA836)the Postdoctoral Research Start-up Foundation of Gansu Province,China(03824034)the Postdoctoral Research Start-up Foundation of Gansu Agricultural University,China(202403)。
文摘A critical challenge for global food security and sustainable agriculture is enhancing crop yields while reducing chemical N inputs.Improving N use efficiency in crops is essential for increasing agricultural productivity.The aim of this study was to evaluate the impacts of intercropping maize with leguminous green manure on grain yield and N utilization under reduced N-fertilization conditions.A field experiment with a split-plot design was conducted in northwestern China from 2018 to 2021.The main plots consisted of two cropping systems:maize-common vetch intercropping(IM)and sole maize(SM).The subplots had three N levels:zero N application(N0,0 kg ha^(-1)),a 25%reduction from the traditional chemical N supply(N1,270 kg ha^(-1)),and the traditional chemical N supply(N2,360 kg ha^(-1)).The results showed that the negative effects of N reduction on maize grain yield and N uptake were compensated by intercropping leguminous green manure,and the improvements increased with cultivation years.The integrated system involving maize-leguminous green manure intercropping and a reduced N supply enhanced N translocation from maize vegetative organs to grains and increased the nitrate reductase and glutamine synthetase activities in maize leaves.The supercompensatory effect in maize leaves increased year by year,reaching values of 16.1,21.3,and 25.5%in 2019,2020,and 2021,respectively.These findings suggest that intercropping maize with leguminous green manure under reduced chemical N input can enhance N assimilation and uptake in maize.By using this strategy,chemical fertilizer is effectively replaced by leguminous green manure,thereby improving N use efficiency and maintaining stable yields in the maize-based intercropping system.
基金supported by the steady supports scientific research of Key Laboratory of Defense Science and Technology,China(No.WDZC20220105)the National Natural Science Foundation of China(Nos.51775020,62073009,U20B2002)the Science Challenge Project,China(No.TZ2018007)。
文摘Thermal Protection System(TPS)with thick tiles,low thermal conductivity,and a short re-entry stage stands as a critical element within reusable aircraft,whose reliability is related to the function and changes with their physical properties,external conditions,and degradation.Meanwhile,due to the limitation of testing resources,epistemic uncertainties stemming from the small samples are present in TPS reliability modeling.However,current TPS reliability modeling methods face challenges in characterizing the relationships among reliability and physical properties,external conditions,degradation,and epistemic uncertainties.Therefore,under the framework of belief reliability theory,a TPS reliability model is constructed,which takes into account the physical principle,external conditions,performance degradation,and epistemic uncertainties.A reliability simulation algorithm is proposed to calculate TPS reliability.Through a case study and comparison analysis,the proposed method is validated as more effective than the existing method.Additionally,reliability sensitivity analysis is conducted to identify the sensitive factors of reliability under the condition of small samples,through which suggestions are provided for TPS functional design and improvement.
基金supported by the faculty research fund of Sejong Universityfunding from the National Research Foundation of Korea(NRF)under grant number NRF-2022R1F1A1071444+2 种基金funding from NRF under grant numbers NRF-2022R1A2B5B03001781Funding provided by the Department of Energy Office of Energy EfficiencyRenewable Energy Vehicles Technology Office。
文摘Rechargeable batteries are essential energy storage devices that power portable devices and electrical vehicles throughout the wo rld.In general,it is thought that the electrochemical performance of recha rgeable batteries is mostly determined by the electrodes within them and that the electrolyte plays a relatively passive role.However,ion transport and storage can be greatly influenced by the electrolyte solution structure,specifically,ion solvation within the bulk and ion desolvation across the electrode/electrolyte interfaces.Herein,we studied the role of the electrolyte as an active component of electrochemical energy storage devices.We found that with an appropriate electrolyte formulation,ion storage in disordered carbonaceous anode materials can occur spontaneously without externally supplied electrical energy.Reduced graphene oxide(RGO)in an ether-based electrolyte demonstrates'spontaneous'ion storage behaviors of adsorbing and inserting the solvated ions utilizing facilitated permeability and wettability of RGO,which results in Coulombic efficiency of~145%due to additional charging capacity of~180 mAh g^(-1)during electrochemical processes.The unexpected spontaneous ion storage behavior was extensively investigated using a combination of electrochemical analyses and diagnostics,advanced characterizations,and computational simulation.We believe the spontaneous ion storage behavior offers a new way to further improve the energy efficiency of practical rechargeable batteries.
基金supported by the National Natural Science Foundation of China(No.52171152).
文摘The present work investigates the microstructural evolution and mechanical properties in a novel medium-Si 12%Cr reduced activation ferritic/martensitic steel cladding tube(Fe-11.8Cr-0.2C-1.4W-0.17Ta-0.2V-0.55Si-0.5Mn,wt%)during multipass cold rolling and annealing.The initial hot-extruded tube exhibited a full martensitic matrix with the prior austenite grain size of~32μm.After annealing,Cr_(23)C_(6) and TaC particles were precipitated,which are basically unchanged(152-183 nm and 84-113 nm,respectively)during the manufacturing process.Meanwhile,with the cold-rolling strain(ε)increasing and subsequent annealing,the martensitic lath gradually diminishes,and the recrystallization volume fraction(f_(r))is increased.Based on the static recrystallization kinetics model,a clear relationship between f_(r) andεis established,in which the newly proposed kinetic equation demonstrates a strong correlation with the experimental results.Furthermore,the yield strength(σ_(YS)=362 MPa)of the final annealed state was much lower than that(σ_(YS)=482 MPa)of the initial annealed state,which can be attributed to the recrystallization from the martensitic matrix to ferritic matrix.Various strengthening mechanisms are further discussed,and the calculated strengths are in good agreement with the experimental results.This work provides a guidance for the optimization of cold-rolling and annealing treatments in the manufacture of cladding tube.
