Developing high-performance alloys with gigapascal strength and excellent ductility is crucial for modern engineering applications.The concept of multi-component high/medium entropy alloys(H/MEAs)provides an innovativ...Developing high-performance alloys with gigapascal strength and excellent ductility is crucial for modern engineering applications.The concept of multi-component high/medium entropy alloys(H/MEAs)provides an innovative approach to designing such alloys.In this work,we developed the Co_(1.5)CrNi_(1.5)Al_(0.2)Ti_(0.2)MEA,which exhibits outstanding mechanical properties at room temperature through low-temperature pre-aging followed by annealing treatment.Tensile testing reveals that the MEA possesses an ultrahigh yield strength of 20±0785 MPa,an ultimate tensile strength of 2365±70 MPa,and exceptional ductility of 15.8%±1.7%.The superior tensile properties are attributed to the formation of fully recrystal-lized heterogeneous structures(HGS)composed of ultrafine grain(UFG)and fine grain(FG)regions,along with discontinuous precipitation of coherent nano-size lamellar L1_(2)precipitates.The mechanical incompatibility between the UFG region and the FG regions during deformation induces the accumulation of a large number of geometrically necessary dislocations at the interface,resulting in strain distribution and hetero-deformation-induced(HDI)stress accumulation,contributing significantly to HDI strengthening.HDI strengthening,precipitation strengthening,and grain boundary strengthening are the primary mechanisms responsible for the ultra-high yield strength of the MEA.During deformation,the dominant deformation mechanisms include dislocation slip,deformation-induced stacking faults,and Lomer-Cottrell locks,with minor deformation twinning.The synergistic interaction of these multiple deformation modes provides the MEA with excellent work hardening capability,delaying plastic instability and achieving an excellent combination of strength and ductility.This study provides an effective strategy for synergistically strengthening MEAs by combining HDI strengthening with traditional strengthening mechanisms.These findings pave the way for the development of advanced structural materials with high performance tailored for demanding applications in engineering.展开更多
Low-concentration coal mine methane(LC-CMM),which is predominantly composed of methane,serves as a clean and low-carbon energy resource with significant potential for utilization.Utilizing LC-CMM as fuel for solid oxi...Low-concentration coal mine methane(LC-CMM),which is predominantly composed of methane,serves as a clean and low-carbon energy resource with significant potential for utilization.Utilizing LC-CMM as fuel for solid oxide fuel cells(SOFCs)represents an efficient and promising strategy for its effective utilization.However,direct application in Ni-based anodes induces carbon deposition,which severely degrades cell performance.Herein,a medium-entropy oxide Sr_(2)FeNi_(0.1)Cr_(0.3)Mn_(0.3)Mo_(0.3)O_(6−δ)(SFNCMM)was developed as an anode internal reforming catalyst.Following reduction treatment,FeNi_(3) nano-alloy particles precipitate on the surface of the material,thereby significantly enhancing its catalytic activity for LC-CMM reforming process.The catalyst achieved a methane conversion rate of 53.3%,demonstrating excellent catalytic performance.Electrochemical evaluations revealed that SFNCMM-Gd_(0.1)Ce_(0.9)O_(2−δ)(GDC)with a weight ratio of 7:3 exhibited superior electrochemical performance when employed as the anodic catalytic layer.With H_(2) and LC-CMM as fuels,the single cell achieved maximum power densities of 1467.32 and 1116.97 mW·cm^(−2) at 800℃,respectively,with corresponding polarization impedances of 0.17 and 1.35Ω·cm^(2).Furthermore,the single cell maintained stable operation for over 100 h under LC-CMM fueling without significant carbon deposition,confirming its robust resistance to carbon formation.These results underscore the potential of medium-entropy oxides as highly effective catalytic layers for mitigating carbon deposition in SOFCs.展开更多
The dynamics of fluid and non-buoyant particles in a librating horizontal annulus is studied experimentally.In the absence of librations,the granular material forms a cylindrical layer near the outer boundary of the a...The dynamics of fluid and non-buoyant particles in a librating horizontal annulus is studied experimentally.In the absence of librations,the granular material forms a cylindrical layer near the outer boundary of the annulus and undergoes rigid-body rotation with the fluid and the annulus.It is demonstrated that the librational liquefaction of the granular material results in pattern formation.This self-organization process stems from the excitation of inertial modes induced by the oscillatory motion of liquefied granular material under the influence of the gravitational force.The inertial wave induces vortical fluid flow which entrains particles from rest and forms eroded areas that are equidistant from each other along the axis of rotation.Theoretical analysis and experiments demonstrate that a liquefied layer of granular material oscillates with a radian frequency equal to the angular velocity of the annulus and interacts with the inertial wave it excites.The new phenomenon of libration-induced pattern formation is of practical interest as it can be used to control multiphase flows and mass transfer in rotating containers in a variety of industrial processes.展开更多
Accurate acquisition of the rock stress is crucial for various rock engineering applications.The hollow inclusion (HI) technique is widely used for measuring in-situ rock stress.This technique calculates the stress te...Accurate acquisition of the rock stress is crucial for various rock engineering applications.The hollow inclusion (HI) technique is widely used for measuring in-situ rock stress.This technique calculates the stress tensor by measuring strain using an HI strain cell.However,existing analytical solutions for stress calculation based on an HI strain cell in a double-layer medium are not applicable when an HI strain cell is used in a three-layer medium,leading to erroneous stress calculations.To address this issue,this paper presents a method for calculating stress tensors in a three-layer medium using numerical simulations,specifically by obtaining a constitutive matrix that relates strain measurements to stress tensors in a three-layer medium.Furthermore,using Latin hypercube sampling (LHS) and orthogonal experimental design strategies,764 groups of numerical models encompassing various stress measurement scenarios have been established and calculated using FLAC^(3D)software.Finally,a surrogate model based on artificial neural network (ANN) was developed to predict constitutive matrices,achieving a goodness of fit (R^(2)) of 0.999 and a mean squared error (MSE) of 1.254.A software program has been developed from this surrogate model for ease of use in practical engineering applications.The method’s accuracy was verified through numerical simulations,analytical solution and laboratory experiment,demonstrating its effectiveness in calculating stress in a three-layer medium.The surrogate model was applied to calculate mining-induced stress in the roadway roof rock of a coal mine,a typical case for stress measurement in a three-layer medium.Errors in stress calculations arising from the use of existing analytical solutions were corrected.The study also highlights the significant errors associated with using double-layer analytical solutions in a three-layer medium,which could lead to inappropriate engineering design.展开更多
Drying operations are of grave importance to realize the reduction and utilization of sewage sludge resources,but the conventional thermal evaporation drying(TED)technology presents challenges due to the need for a la...Drying operations are of grave importance to realize the reduction and utilization of sewage sludge resources,but the conventional thermal evaporation drying(TED)technology presents challenges due to the need for a large amount of thermal energy to conquer the phase-change latent heat of moisture.Herein,we report a non-phase change technology based on particle high-speed self-rotation in a cyclone for fast,low-temperature drying of viscous sludge with high-moisture contents.Dispersed phase medium(DPM)is introduced into the cyclone self-rotation drying(CSRD)reactor to enhance the dispersion of the viscous sludge.The effects of carrier gas temperature,feeding rate,size,and proportion of DPM particles in the drying process are systematically examined.Under optimal operating conditions,the weighted content of moisture in the viscous sludge could be reduced from 80%to 15.01%in less than 5 s,achieving a high drying efficiency of 95.79%.Theoretical calculations also reveal that 89.26%of the moisture is removed through non-phase change pathway,contributing to a 522-fold increase in the drying rate of CSRD compared to TED technology.This investigation presents a sustainable effective approach for high moisture viscous sludge treatment with low energy consumption and carbon emissions.展开更多
This article presents a mathematical model addressing a scenario involving a hybrid nanofluid flow between two infinite parallel plates.One plate remains stationary,while the other moves downward at a squeezing veloci...This article presents a mathematical model addressing a scenario involving a hybrid nanofluid flow between two infinite parallel plates.One plate remains stationary,while the other moves downward at a squeezing velocity.The space between these plates contains a Darcy-Forchheimer porous medium.A mixture of water-based fluid with gold(Au)and silicon dioxide(Si O2)nanoparticles is formulated.In contrast to the conventional Fourier's heat flux equation,this study employs the Cattaneo-Christov heat flux equation.A uniform magnetic field is applied perpendicular to the flow direction,invoking magnetohydrodynamic(MHD)effects.Further,the model accounts for Joule heating,which is the heat generated when an electric current passes through the fluid.The problem is solved via NDSolve in MATHEMATICA.Numerical and statistical analyses are conducted to provide insights into the behavior of the nanomaterials between the parallel plates with respect to the flow,energy transport,and skin friction.The findings of this study have potential applications in enhancing cooling systems and optimizing thermal management strategies.It is observed that the squeezing motion generates additional pressure gradients within the fluid,which enhances the flow rate but reduces the frictional drag.Consequently,the fluid is pushed more vigorously between the plates,increasing the flow velocity.As the fluid experiences higher flow rates due to the increased squeezing effect,it spends less time in the region between the plates.The thermal relaxation,however,abruptly changes the temperature,leading to a decrease in the temperature fluctuations.展开更多
High-entropy oxides(HEOs)derive their exceptional properties from the atomic-level homogenization of multiple constituent elements within the crystal lattice,which induces a sophisticated local environment that fundam...High-entropy oxides(HEOs)derive their exceptional properties from the atomic-level homogenization of multiple constituent elements within the crystal lattice,which induces a sophisticated local environment that fundamentally reconfigures electron density distributions and coordination environment at active sites.However,the mechanisms by which multi-component systems in HEOs precisely regulate high-activity catalytic sites remain poorly understood.This work addresses this gap by designing medium-entropy perovskite oxides through the strategic incorporation of transition metals with distinct electronegativities and ionic radii,aiming to unravel how local environmental modifications impact the energy band location,coordination states,and adsorption behavior of the Co site.A family of A_(4)BO_(4)-type medium-entropy oxides PrSr(Fe_(0.2)Co_(0.2)Ni_(0.2)Cu_(0.2)M_(0.2))O_(4)(M=Sc,Cr,Mn)was successfully synthesized.Divergent atomic properties among Sc,Cr,and Mn(electronegativity,ionic size,and metal-oxygen bond strength)triggered pronounced electron redistribution,effectively tuning the d-band center of Co.Remarkably,Cr substitution significantly enhanced O_(4) adsorption at Co-active sites,as indicated by an elongated O-O bond length(1.234Å→1.279Å).Concurrently,Cr doping destabilized the M'-O-Cr bonds(M'=Fe,Co,Ni,Cu)and lowered the thermodynamic barrier for oxygen vacancy formation.Electrochemical tests revealed that PrSr(Fe_(0.2)Co_(0.2)Ni_(0.2)Cu_(0.2)Cr_(0.2))O_(4)(PSMO-Cr)exhibited the highest electrical conductivity and fastest oxygen surface exchange kinetics.At 700℃,the area-specific resistance(ASR)of the PSMO-Cr cathode was 0.07Ωcm^(2).Corresponding fuel cells achieved a maximum power density of 0.76 W cm^(-2).In electrolysis mode,the maximum current density reached 0.56 A cm^(-2) under 1.3 V at 700℃using PSMO-Cr as the anode.These results demonstrate that PSMO-Cr is a promising bifunctional catalyst for energy conversion applications.展开更多
Ship operations are crucial to global trade,and their decarbonization is essential to mitigate climate change.This study evaluates the economic viability of existing and emerging decarbonization technologies in mariti...Ship operations are crucial to global trade,and their decarbonization is essential to mitigate climate change.This study evaluates the economic viability of existing and emerging decarbonization technologies in maritime shipping using the levelized cost of energy methodology.It includes a detailed comparative analysis based on essential criteria and sensitivity assessments to highlight the economic impacts of technological advancements.Key factors influencing total costs include fuel costs,carbon pricing,and energy demands for carbon capture.The findings reveal that methanol is more cost-effective than heavy fuel oil(HFO)when priced below 3000 CNY/t,assuming HFO costs 4400 CNY/t.Additionally,methanol with post-combustion carbon capture is less expensive than pre-combustion carbon capture.When carbon prices rise above 480 CNY/t,carbon capture technologies prove more economical than purchasing carbon emission allowances for HFO and liquefied natural gas.Enhanc-ing the use of exhaust gas waste heat is recommended for cost savings.Post-combustion carbon capture also shows greater efficiency,requiring about 1.1 GJ/t less energy than pre-combustion methods,leading to lower overall costs.Future research should focus on market mechanisms to stabilize fuel prices and develop less energy-intensive carbon capture technologies.This study offers critical insights into effective decarbonization strategies for advancing global maritime trade in the present and future.展开更多
Paying an additional RMB 2 could have your next milk tea delivered by drone to your balcony in just five minutes.This small fee represents the vast potential of the trillion-yuan lowaltitude economy.
Hard tissue repair materials that balance high strength with low modulus are highly promising,representing a transformative focus in applied biomaterials research.In this study,Ti-Nb alloys with high performance are p...Hard tissue repair materials that balance high strength with low modulus are highly promising,representing a transformative focus in applied biomaterials research.In this study,Ti-Nb alloys with high performance are prepared by a low-cost process for orthopedic applications.Phase composition,modulus,compressive strength and recovery properties are effectively manipulated by tailoring trace amounts of interstitial oxygen.With increasing oxygen concentration in sintered Ti-Nb alloys,theβ(body centered cubic)phase was stabilized due to the lattice distortion.The elastic modulus declined from 91 to 24 GPa.The compressive strength slightly decreased from 1595 to 1404 MPa and yield strength increased from 760 to 904 MPa.Additionally,the recovery properties were enhanced by the interstitial oxygen as a shape memory alloy.The utilization of trace oxygen serves to modulate the thermoelastic martensitic transformation in Ti-Nb alloys,thereby obtaining appropriate mechanical properties.A notable reduction in modulus is achieved while maintaining high strength,which facilitates the development of orthopedic implants capable of withstanding more complex forces.展开更多
The present investigation inspects the unsteady,incompressible MHD-induced flow of a ternary hybrid nanofluid made of SiO_(2)(silicon dioxide),ZnO(zinc oxide),and MWCNT(multi-walled carbon nanotubes)suspended in a wat...The present investigation inspects the unsteady,incompressible MHD-induced flow of a ternary hybrid nanofluid made of SiO_(2)(silicon dioxide),ZnO(zinc oxide),and MWCNT(multi-walled carbon nanotubes)suspended in a water-ethylene glycol base fluid between two perforated squeezing Riga plates.This problem is important because it helps us understand the complicated connections between magnetic fields,nanofluid dynamics,and heat transport,all of which are critical for designing thermal management systems.These findings are especially useful for improving the design of innovative cooling technologies in electronics,energy systems,and healthcare applications.No prior study has been done on the theoretical study of the flow of ternary nanofluid(SiO_(2)+ZnO+MWCNT/Water−EthylGl ycol,(60∶40))past a pierced squeezed Riga plates using the boundary value problem solver 4th-order collocation(BVP4C)numerical approach to date.So,the current work has been carried out to fill this gap,and the core purpose of this study is to explore the aspects that enhance the heat transfer of base fluids(H_(2)O/EG)suspended with three nanomaterials SiO_(2),ZnO,and MWCNT.The Riga plates introduce electromagnetic forcing through an embedded array of magnets and electrodes,generating Lorentz forces to regulate the flow.The squeezing effect introduces dynamic boundary movement,which enhances mixing;however,permeability,due to porosity,replicates the true material limits.Similarity transformations of the Navier-Stokes and energy equations result in a highly nonlinear set of ordinary differential equations that govern momentum and thermal energy transport.The subsequent boundary value problem is solved utilizing the BVP4C numerical approach.The study observes the impact of magnetic parameters,squeezing velocity,solid volume percentages of the three nanoparticles,and porous medium factors on velocity and temperature fields.Results show that magnetic fields reduce the velocity profile by 6.75%due to increased squeezing and medium effects.Tri-hybrid nanofluids notice a 9%rise in temperature with higher thermal radiation.展开更多
For red pear,the anthocyanin content is a crucial factor determining the fruit skin color,which affects consumer preferences.Low overnight temperatures promote anthocyanin accumulation,but the molecular mechanism resp...For red pear,the anthocyanin content is a crucial factor determining the fruit skin color,which affects consumer preferences.Low overnight temperatures promote anthocyanin accumulation,but the molecular mechanism responsible is unclear.In this study,‘Hongzaosu’pear(Pyrus pyrifolia×Pyrus communis)fruit were treated with a low nighttime temperature(LNT,16℃)or a warm nighttime temperature(WNT,26℃),with sampling conducted within two diurnal cycles.The results showed that LNT promoted anthocyanin accumulation in the fruit skin.The structural anthocyanin biosynthetic genes PpCHS,PpF3H,and PpUFGT exhibited a rhythmic increase in expression at night under LNT.To examine the underlying mechanism,RNA sequencing was conducted using pear calli exposed to LNT and WNT for different durations(24,48,72,or 96 h).Transcriptome analysis revealed 285 differentially expressed genes(DEGs)common to all pairwise comparisons of LNT-and WNT-treated calli of‘Clapp's Favorite’(P.communis)at the sampling time points.KEGG pathway and gene ontology enrichment analyses indicated that the common DEGs were enriched in secondary metabolic processes and phenylpropanoid metabolic processes,which are associated with anthocyanin biosynthesis.The transcription factor PpCDF5,which was responsive to LNT,was selected for further study.Dual-luciferase assays showed that PpCDF5 activated the transcription of anthocyanin biosynthetic genes PpMYB10,PpCHS,PpF3H,PpDFR,PpANS,and PpUFGT.The yeast one-hybrid and EMSA assays demonstrated that PpCDF5 directly binds to the PpF3H promoter,which contains an AAAG motif.Overexpression of PpCDF5 in pear calli and transient overexpression in pear fruit both increased anthocyanin accumulation.The results indicate that PpCDF5 is involved in LNT-induced anthocyanin biosynthesis in pear fruit and provide insights into the molecular regulation of commercial fruit coloration.展开更多
The effect of plasma and charged particle interaction with spacecraft in a low Earth orbit(LEO)environment leads to ion focusing and the formation of an ion void in the downstream region as a result of charging.Simula...The effect of plasma and charged particle interaction with spacecraft in a low Earth orbit(LEO)environment leads to ion focusing and the formation of an ion void in the downstream region as a result of charging.Simulations and investigations using a fixed potential imposed on the spacecraft showed the nonsignificance of geophysical parameter changes to ion focusing.Variation of the temperature ratio(T_(r))contributed only to local ion focusing and manifested as two-ion streamers dispersed at the upper and lower edges of the spacecraft-the outermost layers of the satellite structure at the top and bottom,respectively.A simulation involving changing the ambient plasma density(N_(p))also showed the formation of local ion focusing,in which ions were more concentrated as the density increased.Furthermore,auroral electron density(N_(ae))variation had no clear impact on ion focusing,as indicated by static two-ion structures in the wake field.However,variation of the object potential(ϕ)strongly affected ion focusing formation,leading to distortion of the initial ion void region behind the spacecraft.The formation of ion focusing in this study was subject to the electric field produced by the object potential and the ambipolar electric field resulting from plasma expansion in the downstream region.展开更多
[Objectives]To investigate the clinical efficacy of core stability training combined with conventional rehabilitation in the functional recovery of patients suffering from chronic low back pain.[Methods]A randomized c...[Objectives]To investigate the clinical efficacy of core stability training combined with conventional rehabilitation in the functional recovery of patients suffering from chronic low back pain.[Methods]A randomized controlled trial design was employed in this study.Ninety patients with chronic low back pain were recruited and randomly assigned to either a control group(n=45),which received conventional rehabilitation,or an experimental group(n=45),which received conventional rehabilitation combined with core stability training.Both groups underwent treatment for 6 weeks.Assessments were conducted using the visual analogue scale(VAS),Oswestry disability index(ODI),and finger-to-floor test prior to treatment,6 weeks following treatment,and during the follow-up period,respectively.[Results]Prior to treatment,no statistically significant differences were observed between the two patient groups in terms of general information and various baseline measurements(P>0.05).Following 6 weeks of treatment and throughout the follow-up period,both groups demonstrated significant improvements in VAS scores,ODI scores,and lumbar anteflexion range of motion compared to baseline measurements(P<0.05).Notably,the magnitude of improvement in the experimental group exceeded that of the control group,with this inter-group difference reaching statistical significance(P<0.05).No serious adverse reactions were reported during the treatment process.[Conclusions]Core stability training combined with conventional rehabilitation can significantly enhance the alleviation of pain and functional impairments in patients suffering from chronic low back pain.This approach holds valuable implications for the optimization of rehabilitation treatment protocols.展开更多
The P2-type Fe/Mn-based layered oxides,with cost advantages and high theoretical capacity,are considered one of the promising cathode materials for sodium-ion batteries(SIBs).However,the commercial development of thes...The P2-type Fe/Mn-based layered oxides,with cost advantages and high theoretical capacity,are considered one of the promising cathode materials for sodium-ion batteries(SIBs).However,the commercial development of these materials is impeded by two main factors:the MnO_(6) structure distortion induced by the Jahn-Teller(J-T)effect of Mn^(3+),and the unfavorable phase transitions that occur during the insertion and extraction of Na^(+).Here,we present a strategy to improve structural stability by incorporating cost-effective,robust Al-O bonds.This approach induces localized adjustments in the electronic structu re and a pinning effect,which limits the deformation of the transition metal(TM)layers,strengthens the electrostatic bonding within the TM layers,and expands the Na layer spacing.Consequently,the Na_(0.67)Fe_(0.4)Mn_(0.54)Al_(0.06)O_(2) cathode demonstrates a capacity of 168.8 mAh g^(-1) at 0.1 C,maintaining89.2%of its original capacity after 200 cycles at 1 C.Through in situ electrochemical impedance spectroscopy(EIS)with dynamic resistance transformation(DRT)analysis,ex situ X-ray absorption spectroscopy(XAS),and in situ X-ray diffraction(XRD),the study demonstrates a reduction in the J-T effect,enhanced kinetic performance,and the inhibition of detrimental phase transitions.This study offers new avenues to the development and design of future low-cost Fe/Mn-based cathodes.展开更多
Commercial carbonate electrolytes suffer from ion transport difficulty in bulk electrolytes and interphase at low temperatures,bringing challenges to the application of lithium-ion batteries(LIBs)at low temperatures.H...Commercial carbonate electrolytes suffer from ion transport difficulty in bulk electrolytes and interphase at low temperatures,bringing challenges to the application of lithium-ion batteries(LIBs)at low temperatures.Herein,the ester solvent of methyl propionate(MP)with low melting point and low viscosity was used to tackle ion transport difficulty in electrolytes.Fluorinated ester was further added to accelerate interfacial transport through intermolecular interactions.The influence of fluorinated esters with different fluorination degrees on the solvation structure of electrolytes and the performance of batteries was further studied.As a result,methyl pentafluoropropionate(M5F)with five fluorine atoms was selected for its optimal interactions with both Li+and MP solvent in the primary solvation structure,contributing to desired solvation structure for fast interfacial transport.The LiFePO4(LFP)||graphite cell with LiFSI-MP-M5F electrolyte exhibited a high cyclability of 85.8%after 120 cycles and retained 81.2%of room-temperature capacity when charged and discharged at−30℃.1 Ah LFP||graphite pouch cell with high cathode loading(20 mg/cm^(2))in LiFSI-MP-M5F electrolyte exhibited 0.85 Ah capacity when charged and discharged at−20℃.This work provides a guidance for electrolyte design by synergistic fluorinated and non-fluorinated solvents for LIBs at low-temperature application.展开更多
Mini light-emitting diodes(Mini-LEDs)show great application potential in high-end displays owing to their superior pixel density,brightness,responsiveness,and efficiency.However,current packaging materials for Mini-LE...Mini light-emitting diodes(Mini-LEDs)show great application potential in high-end displays owing to their superior pixel density,brightness,responsiveness,and efficiency.However,current packaging materials for Mini-LEDs are predominantly thermally cured,which is energy-and time-consuming and can adversely affect electronic components.In this study,a novel UV-curable silicone resin containing phenyl,disulfide,and acryloyl groups(SPASR)is developed from commercially available siloxanes.The resin exhibits a refractive index(n_(d))higher than 1.5,and it can be cured within 30 s under UV irradiation.After curing,it exhibits an optical transparency exceeding 92%,a lap adhesion strength of up to1.84 MPa,and good thermostability(T_(5%)>265℃).Notably,the volume shrinkage is less than 4.83%,attributed to the release of photopolymerization stress via UV-induced disulfide metathesis during UV curing.Mini-LEDs encapsulated with this resin show luminescence properties comparable to those of conventional thermally-cured sealants,and show excellent sealability wihtout visible penetration after being immersed in red ink for 12 h.Consequently,these excellent properties make the SPASR resin an ideal candidate for microelectronic encapsulation,offering a more reliable and efficient solution for the electronics industry.展开更多
The low-pressure and low-density conditions encountered at high altitudes significantly reduce the operating Reynolds number of micro radial-flow turbines,frequently bringing it below the self-similarity critical thre...The low-pressure and low-density conditions encountered at high altitudes significantly reduce the operating Reynolds number of micro radial-flow turbines,frequently bringing it below the self-similarity critical threshold of 3.5×10^(4).This departure undermines the applicability of conventional similarity-based design approaches.In this study,micro radial-flow turbines with rotor diameters below 50 mm are investigated through a combined approach integrating high-fidelity numerical simulations with experimental validation,aiming to elucidate the mechanisms by which low Reynolds numbers influence aerodynamic and thermodynamic performance.The results demonstrate that decreasing Reynolds number leads to boundary-layer thickening on blade surfaces,enhanced flow separation on the suction side,and increased secondary-flow losses within the blade passages.These effects jointly produce a pronounced and non-linear deterioration of turbine efficiency.Geometric scaling analysis further indicates that efficiency losses intensify with decreasing turbine size,and become particularly severe at low rotational speeds and high expansion ratios.Detailed flow-field analyses reveal a direct link between the degradation of blade loading distribution and the amplification of transverse pressure gradients under low-Reynolds-number conditions,providing physical insight into the observed performance decline.展开更多
Thermomagnetic generation(TMG),a heat-to-electricity conversion technology based on the thermomagnetic effect,offers high reliability and broad adaptability to diverse heat sources.By exploiting the temperature-depend...Thermomagnetic generation(TMG),a heat-to-electricity conversion technology based on the thermomagnetic effect,offers high reliability and broad adaptability to diverse heat sources.By exploiting the temperature-dependent magnetization of thermomagnetic materials,TMG converts thermal energy into electrical energy through cyclic changes in magnetic flux based on Faraday's law.The performance of TMG systems is largely governed by the intrinsic properties of the working materials and the design of device architecture.Ideal TMG materials exhibit sharp and reversible magnetization transitions near the operating temperature,low thermal hysteresis,and high thermal conductivity.Device configurations can be broadly categorized into active and passive systems:active TMG devices rely on controlled thermal cycling and optimized magnetic circuits for enhanced output,whereas passive devices utilize self-actuated mechanical motion to generate electricity.In this topical review,we provide a comprehensive overview of recent advances in TMG materials and device configurations.Furthermore,we discuss future development trends and offer perspectives on experimental strategies to advance this field.展开更多
基金supported by the National Key Research and Development Program of China(No.2022YFA1603800)the National Natural Science Foundation of China(No.12274362).
文摘Developing high-performance alloys with gigapascal strength and excellent ductility is crucial for modern engineering applications.The concept of multi-component high/medium entropy alloys(H/MEAs)provides an innovative approach to designing such alloys.In this work,we developed the Co_(1.5)CrNi_(1.5)Al_(0.2)Ti_(0.2)MEA,which exhibits outstanding mechanical properties at room temperature through low-temperature pre-aging followed by annealing treatment.Tensile testing reveals that the MEA possesses an ultrahigh yield strength of 20±0785 MPa,an ultimate tensile strength of 2365±70 MPa,and exceptional ductility of 15.8%±1.7%.The superior tensile properties are attributed to the formation of fully recrystal-lized heterogeneous structures(HGS)composed of ultrafine grain(UFG)and fine grain(FG)regions,along with discontinuous precipitation of coherent nano-size lamellar L1_(2)precipitates.The mechanical incompatibility between the UFG region and the FG regions during deformation induces the accumulation of a large number of geometrically necessary dislocations at the interface,resulting in strain distribution and hetero-deformation-induced(HDI)stress accumulation,contributing significantly to HDI strengthening.HDI strengthening,precipitation strengthening,and grain boundary strengthening are the primary mechanisms responsible for the ultra-high yield strength of the MEA.During deformation,the dominant deformation mechanisms include dislocation slip,deformation-induced stacking faults,and Lomer-Cottrell locks,with minor deformation twinning.The synergistic interaction of these multiple deformation modes provides the MEA with excellent work hardening capability,delaying plastic instability and achieving an excellent combination of strength and ductility.This study provides an effective strategy for synergistically strengthening MEAs by combining HDI strengthening with traditional strengthening mechanisms.These findings pave the way for the development of advanced structural materials with high performance tailored for demanding applications in engineering.
基金supported by the National Key R&D Program of China(No.2024YFB4007501)the Natural Science Foundation of Jiangsu Province(No.BK20240109)the project of Jiangsu Key Laboratory for Clean Utilization of Carbon Resources(No.BM2024007).
文摘Low-concentration coal mine methane(LC-CMM),which is predominantly composed of methane,serves as a clean and low-carbon energy resource with significant potential for utilization.Utilizing LC-CMM as fuel for solid oxide fuel cells(SOFCs)represents an efficient and promising strategy for its effective utilization.However,direct application in Ni-based anodes induces carbon deposition,which severely degrades cell performance.Herein,a medium-entropy oxide Sr_(2)FeNi_(0.1)Cr_(0.3)Mn_(0.3)Mo_(0.3)O_(6−δ)(SFNCMM)was developed as an anode internal reforming catalyst.Following reduction treatment,FeNi_(3) nano-alloy particles precipitate on the surface of the material,thereby significantly enhancing its catalytic activity for LC-CMM reforming process.The catalyst achieved a methane conversion rate of 53.3%,demonstrating excellent catalytic performance.Electrochemical evaluations revealed that SFNCMM-Gd_(0.1)Ce_(0.9)O_(2−δ)(GDC)with a weight ratio of 7:3 exhibited superior electrochemical performance when employed as the anodic catalytic layer.With H_(2) and LC-CMM as fuels,the single cell achieved maximum power densities of 1467.32 and 1116.97 mW·cm^(−2) at 800℃,respectively,with corresponding polarization impedances of 0.17 and 1.35Ω·cm^(2).Furthermore,the single cell maintained stable operation for over 100 h under LC-CMM fueling without significant carbon deposition,confirming its robust resistance to carbon formation.These results underscore the potential of medium-entropy oxides as highly effective catalytic layers for mitigating carbon deposition in SOFCs.
基金funded by the Ministry of Education of the Russian Federation within the framework of a state assignment,number 1023032300071-6-2.3.1.
文摘The dynamics of fluid and non-buoyant particles in a librating horizontal annulus is studied experimentally.In the absence of librations,the granular material forms a cylindrical layer near the outer boundary of the annulus and undergoes rigid-body rotation with the fluid and the annulus.It is demonstrated that the librational liquefaction of the granular material results in pattern formation.This self-organization process stems from the excitation of inertial modes induced by the oscillatory motion of liquefied granular material under the influence of the gravitational force.The inertial wave induces vortical fluid flow which entrains particles from rest and forms eroded areas that are equidistant from each other along the axis of rotation.Theoretical analysis and experiments demonstrate that a liquefied layer of granular material oscillates with a radian frequency equal to the angular velocity of the annulus and interacts with the inertial wave it excites.The new phenomenon of libration-induced pattern formation is of practical interest as it can be used to control multiphase flows and mass transfer in rotating containers in a variety of industrial processes.
基金funding support from the National Natural Science Foundation of China (Nos. 42477208 and 52079134)the Natural Science Foundation of Hubei Province, China (No. 2024AFA072)+2 种基金the Youth Innovation Promotion Association CAS (No. 2022332)the National Key R&D Program of China (No. 2024YFF0508203)the Open Research Fund of State Key Laboratory of Geomechanics and Geotechnical Engineering Safety (Nos. SKLGME-JBGS2402 and SKLGME022022)。
文摘Accurate acquisition of the rock stress is crucial for various rock engineering applications.The hollow inclusion (HI) technique is widely used for measuring in-situ rock stress.This technique calculates the stress tensor by measuring strain using an HI strain cell.However,existing analytical solutions for stress calculation based on an HI strain cell in a double-layer medium are not applicable when an HI strain cell is used in a three-layer medium,leading to erroneous stress calculations.To address this issue,this paper presents a method for calculating stress tensors in a three-layer medium using numerical simulations,specifically by obtaining a constitutive matrix that relates strain measurements to stress tensors in a three-layer medium.Furthermore,using Latin hypercube sampling (LHS) and orthogonal experimental design strategies,764 groups of numerical models encompassing various stress measurement scenarios have been established and calculated using FLAC^(3D)software.Finally,a surrogate model based on artificial neural network (ANN) was developed to predict constitutive matrices,achieving a goodness of fit (R^(2)) of 0.999 and a mean squared error (MSE) of 1.254.A software program has been developed from this surrogate model for ease of use in practical engineering applications.The method’s accuracy was verified through numerical simulations,analytical solution and laboratory experiment,demonstrating its effectiveness in calculating stress in a three-layer medium.The surrogate model was applied to calculate mining-induced stress in the roadway roof rock of a coal mine,a typical case for stress measurement in a three-layer medium.Errors in stress calculations arising from the use of existing analytical solutions were corrected.The study also highlights the significant errors associated with using double-layer analytical solutions in a three-layer medium,which could lead to inappropriate engineering design.
基金supported by the National Key Research and Development Program of China(2019YFA0705800)the National Natural Science Foundation of China(52030001)the Science&Technology Commission of Shanghai Municipality(20dz1207600).
文摘Drying operations are of grave importance to realize the reduction and utilization of sewage sludge resources,but the conventional thermal evaporation drying(TED)technology presents challenges due to the need for a large amount of thermal energy to conquer the phase-change latent heat of moisture.Herein,we report a non-phase change technology based on particle high-speed self-rotation in a cyclone for fast,low-temperature drying of viscous sludge with high-moisture contents.Dispersed phase medium(DPM)is introduced into the cyclone self-rotation drying(CSRD)reactor to enhance the dispersion of the viscous sludge.The effects of carrier gas temperature,feeding rate,size,and proportion of DPM particles in the drying process are systematically examined.Under optimal operating conditions,the weighted content of moisture in the viscous sludge could be reduced from 80%to 15.01%in less than 5 s,achieving a high drying efficiency of 95.79%.Theoretical calculations also reveal that 89.26%of the moisture is removed through non-phase change pathway,contributing to a 522-fold increase in the drying rate of CSRD compared to TED technology.This investigation presents a sustainable effective approach for high moisture viscous sludge treatment with low energy consumption and carbon emissions.
文摘This article presents a mathematical model addressing a scenario involving a hybrid nanofluid flow between two infinite parallel plates.One plate remains stationary,while the other moves downward at a squeezing velocity.The space between these plates contains a Darcy-Forchheimer porous medium.A mixture of water-based fluid with gold(Au)and silicon dioxide(Si O2)nanoparticles is formulated.In contrast to the conventional Fourier's heat flux equation,this study employs the Cattaneo-Christov heat flux equation.A uniform magnetic field is applied perpendicular to the flow direction,invoking magnetohydrodynamic(MHD)effects.Further,the model accounts for Joule heating,which is the heat generated when an electric current passes through the fluid.The problem is solved via NDSolve in MATHEMATICA.Numerical and statistical analyses are conducted to provide insights into the behavior of the nanomaterials between the parallel plates with respect to the flow,energy transport,and skin friction.The findings of this study have potential applications in enhancing cooling systems and optimizing thermal management strategies.It is observed that the squeezing motion generates additional pressure gradients within the fluid,which enhances the flow rate but reduces the frictional drag.Consequently,the fluid is pushed more vigorously between the plates,increasing the flow velocity.As the fluid experiences higher flow rates due to the increased squeezing effect,it spends less time in the region between the plates.The thermal relaxation,however,abruptly changes the temperature,leading to a decrease in the temperature fluctuations.
基金supported by the National Natural Science Foundation of China(51872078,52272197,52572219)Heilongjiang Provincial Natural Science Foundation of China(LH2024E106)。
文摘High-entropy oxides(HEOs)derive their exceptional properties from the atomic-level homogenization of multiple constituent elements within the crystal lattice,which induces a sophisticated local environment that fundamentally reconfigures electron density distributions and coordination environment at active sites.However,the mechanisms by which multi-component systems in HEOs precisely regulate high-activity catalytic sites remain poorly understood.This work addresses this gap by designing medium-entropy perovskite oxides through the strategic incorporation of transition metals with distinct electronegativities and ionic radii,aiming to unravel how local environmental modifications impact the energy band location,coordination states,and adsorption behavior of the Co site.A family of A_(4)BO_(4)-type medium-entropy oxides PrSr(Fe_(0.2)Co_(0.2)Ni_(0.2)Cu_(0.2)M_(0.2))O_(4)(M=Sc,Cr,Mn)was successfully synthesized.Divergent atomic properties among Sc,Cr,and Mn(electronegativity,ionic size,and metal-oxygen bond strength)triggered pronounced electron redistribution,effectively tuning the d-band center of Co.Remarkably,Cr substitution significantly enhanced O_(4) adsorption at Co-active sites,as indicated by an elongated O-O bond length(1.234Å→1.279Å).Concurrently,Cr doping destabilized the M'-O-Cr bonds(M'=Fe,Co,Ni,Cu)and lowered the thermodynamic barrier for oxygen vacancy formation.Electrochemical tests revealed that PrSr(Fe_(0.2)Co_(0.2)Ni_(0.2)Cu_(0.2)Cr_(0.2))O_(4)(PSMO-Cr)exhibited the highest electrical conductivity and fastest oxygen surface exchange kinetics.At 700℃,the area-specific resistance(ASR)of the PSMO-Cr cathode was 0.07Ωcm^(2).Corresponding fuel cells achieved a maximum power density of 0.76 W cm^(-2).In electrolysis mode,the maximum current density reached 0.56 A cm^(-2) under 1.3 V at 700℃using PSMO-Cr as the anode.These results demonstrate that PSMO-Cr is a promising bifunctional catalyst for energy conversion applications.
基金supported by the National Key R&D Program of China(No.2022YFC3701500)the Key R&D Plan Projects of Zhejiang Province(No.2024SSYS0072)Zhejiang Provincial Natural Science Foundation(No.LDT23E0601).
文摘Ship operations are crucial to global trade,and their decarbonization is essential to mitigate climate change.This study evaluates the economic viability of existing and emerging decarbonization technologies in maritime shipping using the levelized cost of energy methodology.It includes a detailed comparative analysis based on essential criteria and sensitivity assessments to highlight the economic impacts of technological advancements.Key factors influencing total costs include fuel costs,carbon pricing,and energy demands for carbon capture.The findings reveal that methanol is more cost-effective than heavy fuel oil(HFO)when priced below 3000 CNY/t,assuming HFO costs 4400 CNY/t.Additionally,methanol with post-combustion carbon capture is less expensive than pre-combustion carbon capture.When carbon prices rise above 480 CNY/t,carbon capture technologies prove more economical than purchasing carbon emission allowances for HFO and liquefied natural gas.Enhanc-ing the use of exhaust gas waste heat is recommended for cost savings.Post-combustion carbon capture also shows greater efficiency,requiring about 1.1 GJ/t less energy than pre-combustion methods,leading to lower overall costs.Future research should focus on market mechanisms to stabilize fuel prices and develop less energy-intensive carbon capture technologies.This study offers critical insights into effective decarbonization strategies for advancing global maritime trade in the present and future.
文摘Paying an additional RMB 2 could have your next milk tea delivered by drone to your balcony in just five minutes.This small fee represents the vast potential of the trillion-yuan lowaltitude economy.
基金Project(52501069)supported by the National Natural Science Foundation of ChinaProject(GZC20233172)supported by the Postdoctoral Fellowship Program of China Postdoctoral Science Foundation(CPSF)Project(21B0121)supported by Hunan Provincial Education Department,China。
文摘Hard tissue repair materials that balance high strength with low modulus are highly promising,representing a transformative focus in applied biomaterials research.In this study,Ti-Nb alloys with high performance are prepared by a low-cost process for orthopedic applications.Phase composition,modulus,compressive strength and recovery properties are effectively manipulated by tailoring trace amounts of interstitial oxygen.With increasing oxygen concentration in sintered Ti-Nb alloys,theβ(body centered cubic)phase was stabilized due to the lattice distortion.The elastic modulus declined from 91 to 24 GPa.The compressive strength slightly decreased from 1595 to 1404 MPa and yield strength increased from 760 to 904 MPa.Additionally,the recovery properties were enhanced by the interstitial oxygen as a shape memory alloy.The utilization of trace oxygen serves to modulate the thermoelastic martensitic transformation in Ti-Nb alloys,thereby obtaining appropriate mechanical properties.A notable reduction in modulus is achieved while maintaining high strength,which facilitates the development of orthopedic implants capable of withstanding more complex forces.
基金funded by King Saud University,Riyadh,Saudi Arabia,through the Ongo-ing Research Funding program—Research Chairs(ORF-RC-2025-0127)funded via Princess Nourah bint Abdulrahman University Researchers Supporting Project number(PNURSP2025R443).
文摘The present investigation inspects the unsteady,incompressible MHD-induced flow of a ternary hybrid nanofluid made of SiO_(2)(silicon dioxide),ZnO(zinc oxide),and MWCNT(multi-walled carbon nanotubes)suspended in a water-ethylene glycol base fluid between two perforated squeezing Riga plates.This problem is important because it helps us understand the complicated connections between magnetic fields,nanofluid dynamics,and heat transport,all of which are critical for designing thermal management systems.These findings are especially useful for improving the design of innovative cooling technologies in electronics,energy systems,and healthcare applications.No prior study has been done on the theoretical study of the flow of ternary nanofluid(SiO_(2)+ZnO+MWCNT/Water−EthylGl ycol,(60∶40))past a pierced squeezed Riga plates using the boundary value problem solver 4th-order collocation(BVP4C)numerical approach to date.So,the current work has been carried out to fill this gap,and the core purpose of this study is to explore the aspects that enhance the heat transfer of base fluids(H_(2)O/EG)suspended with three nanomaterials SiO_(2),ZnO,and MWCNT.The Riga plates introduce electromagnetic forcing through an embedded array of magnets and electrodes,generating Lorentz forces to regulate the flow.The squeezing effect introduces dynamic boundary movement,which enhances mixing;however,permeability,due to porosity,replicates the true material limits.Similarity transformations of the Navier-Stokes and energy equations result in a highly nonlinear set of ordinary differential equations that govern momentum and thermal energy transport.The subsequent boundary value problem is solved utilizing the BVP4C numerical approach.The study observes the impact of magnetic parameters,squeezing velocity,solid volume percentages of the three nanoparticles,and porous medium factors on velocity and temperature fields.Results show that magnetic fields reduce the velocity profile by 6.75%due to increased squeezing and medium effects.Tri-hybrid nanofluids notice a 9%rise in temperature with higher thermal radiation.
基金supported by the National Natural Science Foundation of China(Grant Nos.32072545,32272639 and 32260745)Zhejiang Provincial Natural Science Foundation of China(Grant Nos.LTGN23C150009 and LY22C150003)Zhejiang University Experimental Technology Research Project(Grant No.SYBJS202217).
文摘For red pear,the anthocyanin content is a crucial factor determining the fruit skin color,which affects consumer preferences.Low overnight temperatures promote anthocyanin accumulation,but the molecular mechanism responsible is unclear.In this study,‘Hongzaosu’pear(Pyrus pyrifolia×Pyrus communis)fruit were treated with a low nighttime temperature(LNT,16℃)or a warm nighttime temperature(WNT,26℃),with sampling conducted within two diurnal cycles.The results showed that LNT promoted anthocyanin accumulation in the fruit skin.The structural anthocyanin biosynthetic genes PpCHS,PpF3H,and PpUFGT exhibited a rhythmic increase in expression at night under LNT.To examine the underlying mechanism,RNA sequencing was conducted using pear calli exposed to LNT and WNT for different durations(24,48,72,or 96 h).Transcriptome analysis revealed 285 differentially expressed genes(DEGs)common to all pairwise comparisons of LNT-and WNT-treated calli of‘Clapp's Favorite’(P.communis)at the sampling time points.KEGG pathway and gene ontology enrichment analyses indicated that the common DEGs were enriched in secondary metabolic processes and phenylpropanoid metabolic processes,which are associated with anthocyanin biosynthesis.The transcription factor PpCDF5,which was responsive to LNT,was selected for further study.Dual-luciferase assays showed that PpCDF5 activated the transcription of anthocyanin biosynthetic genes PpMYB10,PpCHS,PpF3H,PpDFR,PpANS,and PpUFGT.The yeast one-hybrid and EMSA assays demonstrated that PpCDF5 directly binds to the PpF3H promoter,which contains an AAAG motif.Overexpression of PpCDF5 in pear calli and transient overexpression in pear fruit both increased anthocyanin accumulation.The results indicate that PpCDF5 is involved in LNT-induced anthocyanin biosynthesis in pear fruit and provide insights into the molecular regulation of commercial fruit coloration.
基金Kobe Universitythe National Research and Innovation Agency (BRIN)
文摘The effect of plasma and charged particle interaction with spacecraft in a low Earth orbit(LEO)environment leads to ion focusing and the formation of an ion void in the downstream region as a result of charging.Simulations and investigations using a fixed potential imposed on the spacecraft showed the nonsignificance of geophysical parameter changes to ion focusing.Variation of the temperature ratio(T_(r))contributed only to local ion focusing and manifested as two-ion streamers dispersed at the upper and lower edges of the spacecraft-the outermost layers of the satellite structure at the top and bottom,respectively.A simulation involving changing the ambient plasma density(N_(p))also showed the formation of local ion focusing,in which ions were more concentrated as the density increased.Furthermore,auroral electron density(N_(ae))variation had no clear impact on ion focusing,as indicated by static two-ion structures in the wake field.However,variation of the object potential(ϕ)strongly affected ion focusing formation,leading to distortion of the initial ion void region behind the spacecraft.The formation of ion focusing in this study was subject to the electric field produced by the object potential and the ambipolar electric field resulting from plasma expansion in the downstream region.
文摘[Objectives]To investigate the clinical efficacy of core stability training combined with conventional rehabilitation in the functional recovery of patients suffering from chronic low back pain.[Methods]A randomized controlled trial design was employed in this study.Ninety patients with chronic low back pain were recruited and randomly assigned to either a control group(n=45),which received conventional rehabilitation,or an experimental group(n=45),which received conventional rehabilitation combined with core stability training.Both groups underwent treatment for 6 weeks.Assessments were conducted using the visual analogue scale(VAS),Oswestry disability index(ODI),and finger-to-floor test prior to treatment,6 weeks following treatment,and during the follow-up period,respectively.[Results]Prior to treatment,no statistically significant differences were observed between the two patient groups in terms of general information and various baseline measurements(P>0.05).Following 6 weeks of treatment and throughout the follow-up period,both groups demonstrated significant improvements in VAS scores,ODI scores,and lumbar anteflexion range of motion compared to baseline measurements(P<0.05).Notably,the magnitude of improvement in the experimental group exceeded that of the control group,with this inter-group difference reaching statistical significance(P<0.05).No serious adverse reactions were reported during the treatment process.[Conclusions]Core stability training combined with conventional rehabilitation can significantly enhance the alleviation of pain and functional impairments in patients suffering from chronic low back pain.This approach holds valuable implications for the optimization of rehabilitation treatment protocols.
基金financially supported by the National Natural Science Foundation of China(52274295)the Natural Science Foundation of Hebei Province(E2025501032,E2025501028)+3 种基金the Fundamental Research Funds for the Central Universities(N2523045,N2423051,N2423005,N2423019)the Science and Technology Project of Hebei Education Department(QN2024238)the Central Guided Local Science and Technology Development Fund Project of Hebei Province(254Z1102G)the Basic Research Program Project of Shijiazhuang City for Universities Stationed in Hebei Province(241790937A)。
文摘The P2-type Fe/Mn-based layered oxides,with cost advantages and high theoretical capacity,are considered one of the promising cathode materials for sodium-ion batteries(SIBs).However,the commercial development of these materials is impeded by two main factors:the MnO_(6) structure distortion induced by the Jahn-Teller(J-T)effect of Mn^(3+),and the unfavorable phase transitions that occur during the insertion and extraction of Na^(+).Here,we present a strategy to improve structural stability by incorporating cost-effective,robust Al-O bonds.This approach induces localized adjustments in the electronic structu re and a pinning effect,which limits the deformation of the transition metal(TM)layers,strengthens the electrostatic bonding within the TM layers,and expands the Na layer spacing.Consequently,the Na_(0.67)Fe_(0.4)Mn_(0.54)Al_(0.06)O_(2) cathode demonstrates a capacity of 168.8 mAh g^(-1) at 0.1 C,maintaining89.2%of its original capacity after 200 cycles at 1 C.Through in situ electrochemical impedance spectroscopy(EIS)with dynamic resistance transformation(DRT)analysis,ex situ X-ray absorption spectroscopy(XAS),and in situ X-ray diffraction(XRD),the study demonstrates a reduction in the J-T effect,enhanced kinetic performance,and the inhibition of detrimental phase transitions.This study offers new avenues to the development and design of future low-cost Fe/Mn-based cathodes.
基金supported by the National Key R&D Program of China(No.2022YFB3803400)National Natural Science Foundation of China(Nos.52102054,52020105010,51927803,52188101 and 52072378)+1 种基金Liaoning Province Science and Technology Planning Project(No.2022-BS-007)Fujian Science and Technology Program(No.2023T3025).
文摘Commercial carbonate electrolytes suffer from ion transport difficulty in bulk electrolytes and interphase at low temperatures,bringing challenges to the application of lithium-ion batteries(LIBs)at low temperatures.Herein,the ester solvent of methyl propionate(MP)with low melting point and low viscosity was used to tackle ion transport difficulty in electrolytes.Fluorinated ester was further added to accelerate interfacial transport through intermolecular interactions.The influence of fluorinated esters with different fluorination degrees on the solvation structure of electrolytes and the performance of batteries was further studied.As a result,methyl pentafluoropropionate(M5F)with five fluorine atoms was selected for its optimal interactions with both Li+and MP solvent in the primary solvation structure,contributing to desired solvation structure for fast interfacial transport.The LiFePO4(LFP)||graphite cell with LiFSI-MP-M5F electrolyte exhibited a high cyclability of 85.8%after 120 cycles and retained 81.2%of room-temperature capacity when charged and discharged at−30℃.1 Ah LFP||graphite pouch cell with high cathode loading(20 mg/cm^(2))in LiFSI-MP-M5F electrolyte exhibited 0.85 Ah capacity when charged and discharged at−20℃.This work provides a guidance for electrolyte design by synergistic fluorinated and non-fluorinated solvents for LIBs at low-temperature application.
基金financially supported by the National Natural Science Foundation of China(No.52273104)。
文摘Mini light-emitting diodes(Mini-LEDs)show great application potential in high-end displays owing to their superior pixel density,brightness,responsiveness,and efficiency.However,current packaging materials for Mini-LEDs are predominantly thermally cured,which is energy-and time-consuming and can adversely affect electronic components.In this study,a novel UV-curable silicone resin containing phenyl,disulfide,and acryloyl groups(SPASR)is developed from commercially available siloxanes.The resin exhibits a refractive index(n_(d))higher than 1.5,and it can be cured within 30 s under UV irradiation.After curing,it exhibits an optical transparency exceeding 92%,a lap adhesion strength of up to1.84 MPa,and good thermostability(T_(5%)>265℃).Notably,the volume shrinkage is less than 4.83%,attributed to the release of photopolymerization stress via UV-induced disulfide metathesis during UV curing.Mini-LEDs encapsulated with this resin show luminescence properties comparable to those of conventional thermally-cured sealants,and show excellent sealability wihtout visible penetration after being immersed in red ink for 12 h.Consequently,these excellent properties make the SPASR resin an ideal candidate for microelectronic encapsulation,offering a more reliable and efficient solution for the electronics industry.
基金supported by the Tiangsu Association for Science and Technology(Grant No.JSKX 0225089).
文摘The low-pressure and low-density conditions encountered at high altitudes significantly reduce the operating Reynolds number of micro radial-flow turbines,frequently bringing it below the self-similarity critical threshold of 3.5×10^(4).This departure undermines the applicability of conventional similarity-based design approaches.In this study,micro radial-flow turbines with rotor diameters below 50 mm are investigated through a combined approach integrating high-fidelity numerical simulations with experimental validation,aiming to elucidate the mechanisms by which low Reynolds numbers influence aerodynamic and thermodynamic performance.The results demonstrate that decreasing Reynolds number leads to boundary-layer thickening on blade surfaces,enhanced flow separation on the suction side,and increased secondary-flow losses within the blade passages.These effects jointly produce a pronounced and non-linear deterioration of turbine efficiency.Geometric scaling analysis further indicates that efficiency losses intensify with decreasing turbine size,and become particularly severe at low rotational speeds and high expansion ratios.Detailed flow-field analyses reveal a direct link between the degradation of blade loading distribution and the amplification of transverse pressure gradients under low-Reynolds-number conditions,providing physical insight into the observed performance decline.
基金supported by the National Natural Science Foundation of China(Grant Nos.52171169 and 52101210)the National Key Research and Development Program of China(Grant No.2021YFB3501204)+3 种基金the State Key Laboratory for Advanced Metals and Materials(Grant No.2023-ZD01)USTB Concept Verification Funding Project(Grant No.GNYZ-2024-6)Fundamental Research Funds for the Central Universities(Grant No.FRF-TP-24-004A)USTB Research Center for International People-to-people Exchange in Science,Technology and Civilization(Grant Nos.2024KFZD001 and 2024KFYB004)。
文摘Thermomagnetic generation(TMG),a heat-to-electricity conversion technology based on the thermomagnetic effect,offers high reliability and broad adaptability to diverse heat sources.By exploiting the temperature-dependent magnetization of thermomagnetic materials,TMG converts thermal energy into electrical energy through cyclic changes in magnetic flux based on Faraday's law.The performance of TMG systems is largely governed by the intrinsic properties of the working materials and the design of device architecture.Ideal TMG materials exhibit sharp and reversible magnetization transitions near the operating temperature,low thermal hysteresis,and high thermal conductivity.Device configurations can be broadly categorized into active and passive systems:active TMG devices rely on controlled thermal cycling and optimized magnetic circuits for enhanced output,whereas passive devices utilize self-actuated mechanical motion to generate electricity.In this topical review,we provide a comprehensive overview of recent advances in TMG materials and device configurations.Furthermore,we discuss future development trends and offer perspectives on experimental strategies to advance this field.
