The morphological distribution of absorbent in composites is equally important with absorbents for the overall electromagnetic properties,but it is often ignored.Herein,a comprehensive consideration including electrom...The morphological distribution of absorbent in composites is equally important with absorbents for the overall electromagnetic properties,but it is often ignored.Herein,a comprehensive consideration including electromagnetic component regulation,layered arrangement structure,and gradient concentration distribution was used to optimize impedance matching and enhance electromagnetic loss.On the microscale,the incorporation of magnetic Ni nanoparticles into MXene nanosheets(Ni@MXene)endows suitable intrinsic permittivity and permeability.On the macroscale,the layered arrangement of Ni@MXene increases the effective interaction area with electromagnetic waves,inducing multiple reflection/scattering effects.On this basis,according to the analysis of absorption,reflection,and transmission(A-R-T)power coefficients of layered composites,the gradient concentration distribution was constructed to realize the impedance matching at low-concentration surface layer,electromagnetic loss at middle concentration interlayer and microwave reflection at high-concentration bottom layer.Consequently,the layered gradient composite(LG5-10-15)achieves complete absorption coverage of X-band at thickness of 2.00-2.20 mm with RL_(min) of-68.67 dB at 9.85 GHz in 2.05 mm,which is 199.0%,12.6%,and 50.6%higher than non-layered,layered and layered descending gradient composites,respectively.Therefore,this work confirms the importance of layered gradient structure in improving absorption performance and broadens the design of high-performance microwave absorption materials.展开更多
In photolithography,shortening the exposure wavelength from ultraviolet to extreme ultraviolet(EUV,13.5 nm)and soft X-ray region in terms of beyond EUV(BEUV,6.X nm)and water window X-ray(WWX,2.2–4.4 nm)is expected to...In photolithography,shortening the exposure wavelength from ultraviolet to extreme ultraviolet(EUV,13.5 nm)and soft X-ray region in terms of beyond EUV(BEUV,6.X nm)and water window X-ray(WWX,2.2–4.4 nm)is expected to further miniaturize the technology node down to sub-5 nm level.However,the absorption ability of molecules in these ranges,especially WWX region,is unknown,which should be very important for the utilization of energy.Herein,the molar absorption cross sections of different elements at 2.4 nm of WWX were firstly calculated and compared with the wavelengths of 13.5 nm and 6.7 nm.Based on the absorption cross sections in these ranges and density estimation results from the density-functional theory calculation,the linear absorption coefficients of typical resist materials,including metal-oxy clusters,organic small molecules,polymers,and photoacid generators(PAGs),are evaluated.The analysis suggests that the Zn cluster has higher absorption in BEUV,whereas the Sn cluster has higher absorption in WWX.Doping PAGs with high EUV absorption atoms improves chemically amplified photoresist(CAR)polymer absorption performance.However,for WWX,it is necessary to introduce an absorption layer containing high WWX absorption elements such as Zr,Sn,and Hf to increase the WWX absorption.展开更多
To minimize the calculation errors in the sound absorption coefficient resulting from inaccurate measurements of flow resistivity,a simple method for determining the sound absorption coefficient of soundabsorbing mate...To minimize the calculation errors in the sound absorption coefficient resulting from inaccurate measurements of flow resistivity,a simple method for determining the sound absorption coefficient of soundabsorbing materials is proposed.Firstly,the sound absorption coefficients of a fibrous sound-absorbing material are measured at two different frequencies using the impedance tube method.Secondly,utilizing the empirical formulas for the wavenumber and acoustic impedance in the fibrous material,the flow resistivity and porosity of the sound-absorbing materials are calculated using the MATLAB cycle program.Thirdly,based on the values obtained through reverse calculations,the sound absorption coefficient,the real and the imaginary parts of the acoustic impedance of the sound-absorbing material at different frequencies are theoretically computed.Finally,the accuracy of these theoretical calculations is verified through experiments.The experimental results indicate that the calculated values are basically consistent with the measured values,demonstrating the feasibility and reliability of this method.展开更多
Chitosan(CS),a natural polymer derived from chitin found in the exoskeletons of crustaceans,has garnered significant interest in the pharmaceutical field due to its unique properties,including biocompatibility and bio...Chitosan(CS),a natural polymer derived from chitin found in the exoskeletons of crustaceans,has garnered significant interest in the pharmaceutical field due to its unique properties,including biocompatibility and biodegradability.In recent years,various studies have reported that CS can affect drug bioavailability,and interestingly,it works as an oral absorption enhancer and inhibitor.This review offers an in-depth analysis of the mechanisms underlying such a phenomenon and supports its application as a pharmaceutical excipient.CS enhances oral drug absorption through various mechanisms,such as interaction with the intestinal mucosa,tight junction modulation,inhibition of efflux transporters,enzyme inhibition,solubility and stability enhancement,and complexation.On the other side,CS exhibits the ability to inhibit the absorption of certain drugs by adsorbing to lipids and sterols,modulating bile acids and gut microbiota,altering drug-cell interaction at the polar interface,and mucus-mediated entrapment and interference.Future potential pharmaceutical research in this field includes elucidating the underneath absorption relevant mechanisms,rational use in formulations as excipient,exploring functional CS derivatives,and developing CS-based drug delivery systems.This comprehensive review highlights CS's versatile and significant role in enhancing and inhibiting oral drug absorption,providing insights into the complexities of drug delivery and the potential of CS to improve therapeutic outcomes.展开更多
Using the pulp of Annona squamosa L.as the raw material,polysaccharides were extracted using ultrasonicassisted hot water extraction,with polysaccharide yield as the response variable.The effects of four factors on ex...Using the pulp of Annona squamosa L.as the raw material,polysaccharides were extracted using ultrasonicassisted hot water extraction,with polysaccharide yield as the response variable.The effects of four factors on extraction efficiency were investigated,and the extraction process was optimized using an orthogonal experimental design.The monosaccharide composition of the polysaccharides was analyzed using ion chromatography(IC).The antioxidant activity was evaluated through DPPH radical scavenging,hydroxyl radical(·OH)scavenging,and ferric reducing antioxidant power(FRAP)assays.Additionally,Franz diffusion cells were used to conduct in vitro transdermal absorption experiments,measuring cumulative permeation and calculating permeation kinetics parameters.The results showed that under optimized extraction conditions,the polysaccharide yield was 50.57%±0.02%.Ion chromatography analysis revealed that the main monosaccharide components were arabinose(0.6%),glucose(40.5%),and fructose(58.9%).Antioxidant evaluation indicated that with the addition of 80μL of the extract,the DPPH radical scavenging rate reached 94.13%±0.81%;with 600μL,the hydroxyl radical scavenging rate was 93.33%±0.92%,and the FRAP value was(38.07±1.30)mmol/L.Transdermal absorption experiments demonstrated that the skin retention rates of the polysaccharide aqueous extract at 75%and 100%concentrations were 4.65%±1.52%and 12.37%±2.14%,respectively,with 12 h cumulative permeation rates of 57.43%±1.08%and 74.24%±0.74%.Kinetic analysis of transdermal absorption showed that the process followed zero-order kinetics,indicating a constant release rate under steady-state conditions,consistent with Fick’s diffusion law.This study systematically combined optimization of polysaccharide aqueous extraction,monosaccharide composition analysis,antioxidant activity evaluation,and transdermal permeation performance analysis.It revealed the bioactive properties and potential applications of Annona squamosa L.polysaccharides,particularly in the fields of antioxidant activity and transdermal permeation.The findings provide essential data to support the development of functional products based on Annona squamosa L.polysaccharides.展开更多
Biochar and biochar composites are versatile materials that can be used in many applications.In this study,biochar was prepared from sawdust and combined with the yttrium iron garnet(YIG)nanocrystal to investigate the...Biochar and biochar composites are versatile materials that can be used in many applications.In this study,biochar was prepared from sawdust and combined with the yttrium iron garnet(YIG)nanocrystal to investigate the shielding effectiveness of the composite structure.Firstly,the effect of the pyrolysis temperature on the shielding effectiveness of biochar was investigated.Secondly,biochars combined with YIG nanocrystals with different contents and shielding effectiveness of the composites were investigated.The electromagnetic effectiveness of the samples was investigated within the X band(8-12 GHz).The findings indicate that biochar demonstrates enhanced absorption properties with elevated pyrolysis temperatures.Biochars demonstrated an approximate 40 d B shielding effectiveness,while YIG exhibited approximately 7 d B,corresponding to absorption at 8 GHz.However,the combination of biochar and YIG exhibited exceptional absorption,reaching 67.12 d B at 8 GHz.展开更多
We present a solid 226 nm deep ultraviolet laser system pumped by a Nd:YAG laser.A diamond Raman laser with a 1485 nm wavelength was generated up to 2.53 mJ pumped by a 9.7 mJ 1064 nm laser,which is the highest pulse ...We present a solid 226 nm deep ultraviolet laser system pumped by a Nd:YAG laser.A diamond Raman laser with a 1485 nm wavelength was generated up to 2.53 mJ pumped by a 9.7 mJ 1064 nm laser,which is the highest pulse energy of a second Stokes diamond Raman laser pumped by a 1064 nm laser as we know.Then,the Raman laser is mixed with the frequency-quadrupled 1064 nm laser to produce the 226 nm laser.The maximum output pulse energy at 226 nm reaches 0.49 mJ.The overall conversion efficiency from1064 to 226 nm is up to 1.14%,which is significantly higher than conventional optical parametric oscillator technology for the generation of 226 nm laser.The 226 nm laser system has been used in a laser-induced fluorescence(LIF)experiment of oxygen two-photon to demonstrate its potential for LIF measurements.展开更多
Hydraulic asphalt concrete(HAC)has been increasingly employed as an appropriate impervious structure in hydraulic and hydropower engineering.However,asphalt mortar,usually seen as the matrix of HAC composite,is partic...Hydraulic asphalt concrete(HAC)has been increasingly employed as an appropriate impervious structure in hydraulic and hydropower engineering.However,asphalt mortar,usually seen as the matrix of HAC composite,is particularly prone to damage under combined stress and seepage interactions,and the mesoscale investigations on the damage-seepage coupling behavior of HAC under complex stress states remain limited.This research develops a numerical three-dimensional mesoscale model composed of asphalt mortar and polyhedral aggregate to investigate the stress-damage-seepage coupling behavior in HAC.In this model,asphalt mortar yields the viscoelastic continuum damage law and aggregate obeys the Mazars’elastic-brittle damage law;simultaneously,the effective permeability coefficient of asphalt mortar is assumed to follow an exponential function of damage.The predicted deviatoric stress-strain and hydraulic gradient-seepage curves both are in good agreement with the reported experimental results,which shows the proposed model is valid and reasonable.The simulated results indicate that the damaged asphalt mortar can induce localized areas of high permeability,which in turn affects the overall impervious performance of HAC.展开更多
UHMWPE(Ultra-High Molecular Weight Polyethylene)plain-weave fabric,characterized by its lightweight and high-strength properties,is widely used in protective equipment such as bulletproof vests and stab-resistant vest...UHMWPE(Ultra-High Molecular Weight Polyethylene)plain-weave fabric,characterized by its lightweight and high-strength properties,is widely used in protective equipment such as bulletproof vests and stab-resistant vests,serving as a key material for enhancing protective performance.This study systematically investigates the influence mechanism of interfacial properties on the energy absorption characteristics of UHMWPE-based protective structures through multi-scale experiments and numerical simulations,and establishes a cross-scale design methodology.Innovatively,an orthotropic constitutive model incorporating dynamic friction coefficients is constructed,combined with a modified Johnson-Cook failure criterion,to achieve high-precision simulation of the entire ballistic impact process(error<3.5%).Additionally,a friction field prediction model considering strain rate effects is developed,and the friction evolution laws of UHMWPE and Para-aramid(Kevlar)fabrics under strain rates of 10^(−3) and 10^(−4) s^(−1) are obtained through MTS pull-out tests.The results show that:(1)there exists a critical yarn-yarn friction coefficient(μ=0.2);exceeding this value leads to a 19%reduction in energy absorption capacity,while viscous interfaces increase the energy dissipation peak by 16%;(2)UHMWPE shows kinetically-dominated absorption(58%)with high rate but high load,increasing damage risk.Para-aramid has friction-dominated absorption(53%)with a lower rate but stable load.Hybrid fabrics use potential-dominated absorption(49%)at a moderate rate,balancing stability and protection.(3)3–5 layers of UHMWPE fabric yield optimal cost-effectiveness,with the unit cost reduction rate of the HS+5U scheme reaching 2.74 m/(s·$),which is 91%higher than that of the hybrid scheme.(4)For HS+5U(5-ply UHMWPE),V50 is 520 m/s,meeting primary protection requirement.For hybrid solutions with U/K≥3(e.g.,HS+6U+2K),V50 reaches 580 m/s(≥540 m/s),satisfying advanced protection requirement.This research provides critical references for the design of flexible protective structures and their engineering applications.展开更多
Although traditional gamma-gamma density(GGD)logging technology is widely utilized,its potential environmental risks have prompted the development of more environmentally friendly neutron-gamma density(NGD)logging tec...Although traditional gamma-gamma density(GGD)logging technology is widely utilized,its potential environmental risks have prompted the development of more environmentally friendly neutron-gamma density(NGD)logging technology.However,NGD measurements are influenced by both neutron and gamma radiations.In the logging environment,variations in the formation composition indicate different elemental compositions,which affect the neutron-gamma reaction cross-sections and gamma generation.Compared to traditional gamma sources such as Cs-137,these changes significantly affect the generation and transport of neutron-induced inelastic gamma rays and hinder accurate measurements.To address this,a novel method is proposed that incorporates the mass attenuation coefficient function to account for the effects of various lithologies and pore contents on gamma-ray attenuation,thereby achieving more accurate density measurements by clarifying the transport processes of inelastic gamma rays with varying energies and spatial distributions in varied logging environments.The proposed method avoids the complex correction of neutron transport and is verified through Monte Carlo simulations for its applicability across various lithologies and pore contents,demonstrating absolute density errors that are less than 0.02 g/cm^(3)in clean formations and indicating good accuracy.This study clarifies the NGD mechanism and provides theoretical guidance for the application of NGD logging methods.Further studies will be conducted on extreme environmental conditions and tool calibration.展开更多
The electromagnetic wave absorption of silicon carbide nanowires is improved by their uniform and diverse cross-structures.This study introduces a sustainable and high value-added method for synthesizing silicon carbi...The electromagnetic wave absorption of silicon carbide nanowires is improved by their uniform and diverse cross-structures.This study introduces a sustainable and high value-added method for synthesizing silicon carbide nanowires using lignite and waste silicon powder as raw materials through carbothermal reduction.The staggered structure of nanowires promotes the creation of interfacial polarization,impedance matching,and multiple loss mechanisms,leading to enhanced electromagnetic absorption performance.The silicon carbide nanowires demonstrate outstanding electromagnetic absorption capabilities with the minimum reflection loss of-48.09 d B at10.08 GHz and an effective absorption bandwidth(the reflection loss less than-10 d B)ranging from 8.54 to 16.68 GHz with a thickness of 2.17 mm.This research presents an innovative approach for utilizing solid waste in an environmentally friendly manner to produce broadband silicon carbide composite absorbers.展开更多
Sandwich structures are widely favored for their lightweight,high strength and superior impact mitigation capabilities in blast mitigation and transportation safety applications.Their application in large-scale,high-e...Sandwich structures are widely favored for their lightweight,high strength and superior impact mitigation capabilities in blast mitigation and transportation safety applications.Their application in large-scale,high-energy rockfall protection remains limited due to their relatively low volumetric energy absorption efficiency and the complex fabrication processes of key energy-absorbing components.To address these limitations,this study proposes a novel sandwich structure incorporating mild steel tubes as core energy absorbers to efficiently mitigate highenergy rockfall impacts.A finite element model was developed in LS-DYNA to systematically investigate the deformation and energy absorption behaviors.Comprehensive parametric analyses were conducted to quantify the effects of key design variables,including tube wall thickness,tube spacing(number of tubes),and infill materials.The results demonstrate that increasing tube wall thickness significantly enhances ultimate energy absorption,with 12-mm-thick tubes absorbing 2.2 times more energy than 6-mm-thick tubes.Lateral constraints induced by adjacent tubes improve specific energy absorption per unit displacement by approximately 30%-45%.Furthermore,incorporating infill materials considerably enhances energy absorption,with aluminum foam infills achieving an 81%increase compared to empty tubes.Nevertheless,higher energy absorption capacity typically leads to greater peak impact forces,increasing the number of tubes offers a better balance between energy absorption and impact force,optimizing the structural performance.These findings provide valuable theoretical insights and practical guidelines for designing sandwich structures in civil and infrastructure engineering applications for effective rockfall protection.展开更多
Low-velocity impact tests are carried out to explore the energy absorption characteristics of bio-inspired lattices,mimicking the architecture of the marine sponge organism Euplectella aspergillum.These sea sponge-ins...Low-velocity impact tests are carried out to explore the energy absorption characteristics of bio-inspired lattices,mimicking the architecture of the marine sponge organism Euplectella aspergillum.These sea sponge-inspired lattice structures feature a square-grid 2D lattice with double diagonal bracings and are additively manufactured via digital light processing(DLP).The collapse strength and energy absorption capacity of sea sponge lattice structures are evaluated under various impact conditions and are compared to those of their constituent square-grid and double diagonal lattices.This study demonstrates that sea sponge lattices can achieve an 11-fold increase in energy absorption compared to the square-grid lattice,due to the stabilizing effect of the double diagonal bracings prompting the structure to collapse layer-bylayer under impact.By adjusting the thickness ratio in the sea sponge lattice,up to 76.7%increment in energy absorption is attained.It is also shown that sea-sponge lattices outperform well-established energy-absorbing materials of equal weight,such as hexagonal honeycombs,confirming their significant potential for impact mitigation.Additionally,this research highlights the enhancements in energy absorption achieved by adding a small amount(0.015 phr)of Multi-Walled Carbon Nanotubes(MWCNTs)to the photocurable resin,thus unlocking new possibilities for the design of innovative lightweight structures with multifunctional attributes.展开更多
With the increasing requirements of electromagnetic wave(EMW)absorption,developing EMW absorbers with high-efficiency anti-corrosion performance which can be effectively applied in extreme corrosive environments is im...With the increasing requirements of electromagnetic wave(EMW)absorption,developing EMW absorbers with high-efficiency anti-corrosion performance which can be effectively applied in extreme corrosive environments is imperative and constitutes a hot issue in the current research.Herein,based on the composition modulation of ZrO_(2)and SiO_(2)layer,the dual-oxides confined carbonyl iron(CI@ZrO_(2)/SiO_(2))composite displays a minimum reflection loss(RLmin)of-48.58 dB@1.9 mm and an effective absorption bandwidth(EAB)of 7.62 GHz@1.6 mm.Besides,the CI@ZrO_(2)/SiO_(2)displays superior corrosion resistance with corrosion current density(i_(corr))of 8.62×10^(-7)A/cm^(2)and polarization resistance(Rp)of 3.64×10^(5)Ω.This work proposes a strategy to optimize the broadband EMW absorption properties as well as the mass production toward the corrosion resistance applications.展开更多
Three-dimensional(3D)-printedgraphene aerogels hold promise for electromagneticwave absorption(EWA)engineering due to itsultralow density,outstanding electromagnetic dissipationwith the flexibility and precision of ma...Three-dimensional(3D)-printedgraphene aerogels hold promise for electromagneticwave absorption(EWA)engineering due to itsultralow density,outstanding electromagnetic dissipationwith the flexibility and precision of manufacturingstrategies.However,their high conductivitycauses severe impedance mismatch,limiting EWAperformance.3D printing requirements also constrainthe dielectric properties of printable grapheneinks,hindering the integration of high-performanceabsorbers with advanced manufacturing.This studyproposes a polyacrylic acid(PAA)gel-mediated3D porous graphene oxide(GO)aerogel multiscaleregulation strategy.Precise gel content control enablesdual-gradient tuning of the rheology(Benefitingdirect ink writing(DIW))and dielectric loss(Enhancing EWA)of GO/PAA composites and reduces aerogel density(6.9 mg cm^(-3)from28.2 mg cm^(-3)).Thermal reduction decomposes PAA into amorphous carbon nanoparticles anchored on reduced graphene oxide(rGO),enhancingimpedance matching and absorption via synergistic 0D/2D interfacial polarization and conductive loss.The optimized rGO/PAA aerogelachieves a minimum reflection loss(RL)of-39.86 dB at 2.5 mm and an effective absorption bandwidth(EAB)of 8.36 GHz(9.64-18 GHz)at3.2 mm.Combining DIW and this aerogel,we design a metamaterial absorber(MA)with dual material(dielectric loss)and structural gradients.This MA exhibits an ultrawide EAB of 14 GHz(4-18 GHz)with a total thickness of 7.8 mm.This work establishes a coupled design paradigmof“composition-structure-performance,”providing an engineerable solution for developing lightweight,broadband EWA materials.展开更多
Reconfigurable array architecture has become an important hardware platform for edge-side deployment of convolutional neural networks due to their high parallelism and flexible programmability.However,traditional mult...Reconfigurable array architecture has become an important hardware platform for edge-side deployment of convolutional neural networks due to their high parallelism and flexible programmability.However,traditional multi-branch convolutional networks suffer from computational redundancy,high memory access overhead,and inefficient branch fusion.Therefore,this paper proposes an adaptive multi-branch convolutional module(AMBC)that integrates software-hardware co-optimization.During training,the learnable fusion coefficients are introduced to enable adaptive fusion of multi-scale features,while in the inference phase,the multiple branches and their normalization parameters are merged with the fusion coefficients into a single 3×3 convolutional kernel through operator fusion.On the SIREA-288 reconfigurable platform,compared with unoptimized multi-branch networks,the proposed AMBC reduces external memory accesses by 47.91%and inference latency by 47.20%,achieving a 1.90×speedup.This approach maximizes the utilization of the reconfigurable logic while minimizing both reconfiguration and data-movement overheads in edge inference.展开更多
The development of multifunctional electromagnetic wave-absorbing materials is essential for next-generation flexible electronics and intelligent protection systems.Herein,a novel three-dimensional porous MXene-based ...The development of multifunctional electromagnetic wave-absorbing materials is essential for next-generation flexible electronics and intelligent protection systems.Herein,a novel three-dimensional porous MXene-based film integrated with metallic nickel nanoparticles(Ni-PMF)is designed and synthesized with the potential to address the urgent need for multifunctional electromagnetic wave-absorbing materials in next-generation intelligent systems.By using polystyrene spheres as sacrificial templates,a hierarchical porous architecture is constructed to prevent MXene nanosheet restacking,extend electromagnetic wave propagation paths,and optimize impedance matching.Simultaneously,uniformly distributed Ni nanoparticles introduce abundant heterogeneous interfaces,enhancing interfacial polarization and magnetic loss,which significantly improve electromagnetic wave attenuation.The Ni-PMF film achieves a minimum reflection loss of–64.7 d B and a broad effective absorption bandwidth of 7.2 GHz,covering the full Ku-band and outperforming most reported MXene thin film absorbers.In addition to superior electromagnetic wave absorption,the film demonstrates excellent electrothermal conversion and flexible strain-sensing capabilities,enabling integrated protection and real-time sensing functions.This multifunctional material offers promising potential for next-generation smart flexible electronic systems.展开更多
Ferrite-carbon composites effectively absorb electromagnetic(EM)waves via coupled mechanisms.However,the dynamic evolution of intrinsic polarization and magnetic loss mechanisms following interfacial coupling has long...Ferrite-carbon composites effectively absorb electromagnetic(EM)waves via coupled mechanisms.However,the dynamic evolution of intrinsic polarization and magnetic loss mechanisms following interfacial coupling has long been overlooked,impeding broadening of the ultra-broadband EM wave absorption performance in heterostructures.Herein,via surface ligand modulation,in situ growth of 0D Fe_(3)O_(4)quantum dots(QDs)on the surface of 1D carbon nanotubes triggers grain boundary coupling.The energy rebalancing effect at the interface induces an extreme charge rearrangement within the Fe_(3)O_(4)QDs.This rearrangement enhances dipole orientation hysteresis and charge accumulation,resulting in charge and interfacial polarization losses.Meanwhile,for subcritical Fe_(3)O_(4)QDs,short-range magnetic resonance and magnetic exchange-triggered magnetic resonance transfer synergistically enhance the magnetic loss.Through charge rearrangement/magnetic resonance induced by0D/1D grain boundary coupling,an effective bandwidth of nearly 10 GHz is achieved at a minimal thickness of 2 mm,covering the X and Ku bands.This strategy provides an effective paradigm and novel theoretical insights for ultra-broadband electromagnetic wave absorption applications.展开更多
Flexible materials play a crucial role in protecting against behind armour blunt trauma(BABT).However,their compliance complicates the understanding of failure mechanisms and energy absorption.This study used a combin...Flexible materials play a crucial role in protecting against behind armour blunt trauma(BABT).However,their compliance complicates the understanding of failure mechanisms and energy absorption.This study used a combined experimental and numerical approach to investigate the response and failure modes of a flexible ultra-high-molecular-weight polyethylene(UHMWPE)foam protective sandwich structure(UFPSS)under low-velocity impact(LVI).A finite element(FE)model,accounting for nonlinear large deformation and strain-rate-dependent material behavior,was developed for a woven-UFPSS(featuring a plain-woven fabric structure)subjected to a 50 J impact.Experimental and numerical results showed strong agreement in peak force(error<5%),maximum displacement(error<6%),and buffer time(error<8%).The impact's kinetic energy was mainly converted into internal energy of the fabric and foam materials(~50%),viscous dissipation in the foam core(12%-15%),frictional work at the contact interfaces(5%-6%),and work by the pneumatic fixture clamping force(~38%).This study provides the first investigation of the LVI performance of sandwich structures with all soft material layers,offering significant insights for the application of compliant materials in protective fields.展开更多
Frozen moraine soils are widely distributed across the Tianshan Mountains,the Qinghai-Tibetan Plateau,and other high-altitude regions.Engineering activities,particularly blasting,often induce degradation of the soil m...Frozen moraine soils are widely distributed across the Tianshan Mountains,the Qinghai-Tibetan Plateau,and other high-altitude regions.Engineering activities,particularly blasting,often induce degradation of the soil microstructure,compromising its mechanical integrity and increasing the risk of slope instability and rainfall-triggered debris flows-posing serious threats to infrastructure in cold regions.Previous studies have largely treated frozen soils as homogeneous continua,thereby overlooking key micro-scale processes such as ice-soil interaction,microcrack propagation,and particle breakage.In this study,the dynamic mechanical behavior and microstructural damage mechanisms of frozen moraine soil were systematically investigated under varying temperatures(−5℃,−15℃,and−25℃)and strain rates(50 s^(-1),70 s^(-1),and 90 s^(-1)).Results reveal that both temperature and strain rate significantly influence the dynamic stress-strain response.Energy absorption exhibits a three-stage pattern of increase,stabilization,and decline.At−25℃,increased ice brittleness reduces the peak energy absorption efficiency under impact.To capture the observed nonlinear behavior,a damage-based constitutive model was developed,incorporating coupled effects of impact-induced microcracking,ice-soil interfacial debonding,and particle fracture.The stochastic evolution of interfacial debonding and grain breakage was described using a Weibull statistical framework,linking microstructural deterioration to macroscopic response.The model shows strong agreement with experimental data and accurately simulates key parameters such as peak stress and energy absorption.These findings enhance the understanding of dynamic damage mechanisms in frozen soils and offer a computational tool for the safety assessment and hazard mitigation of engineering structures in cold,high-altitude environments.展开更多
基金support for this work by Key Research and Development Project of Henan Province(Grant.No.241111232300)the National Natural Science Foundation of China(Grant.No.52273085 and 52303113)the Open Fund of Yaoshan Laboratory(Grant.No.2024003).
文摘The morphological distribution of absorbent in composites is equally important with absorbents for the overall electromagnetic properties,but it is often ignored.Herein,a comprehensive consideration including electromagnetic component regulation,layered arrangement structure,and gradient concentration distribution was used to optimize impedance matching and enhance electromagnetic loss.On the microscale,the incorporation of magnetic Ni nanoparticles into MXene nanosheets(Ni@MXene)endows suitable intrinsic permittivity and permeability.On the macroscale,the layered arrangement of Ni@MXene increases the effective interaction area with electromagnetic waves,inducing multiple reflection/scattering effects.On this basis,according to the analysis of absorption,reflection,and transmission(A-R-T)power coefficients of layered composites,the gradient concentration distribution was constructed to realize the impedance matching at low-concentration surface layer,electromagnetic loss at middle concentration interlayer and microwave reflection at high-concentration bottom layer.Consequently,the layered gradient composite(LG5-10-15)achieves complete absorption coverage of X-band at thickness of 2.00-2.20 mm with RL_(min) of-68.67 dB at 9.85 GHz in 2.05 mm,which is 199.0%,12.6%,and 50.6%higher than non-layered,layered and layered descending gradient composites,respectively.Therefore,this work confirms the importance of layered gradient structure in improving absorption performance and broadens the design of high-performance microwave absorption materials.
基金supported by the National Natural Science Foundation of China(22090011,22378052)the Fundamental Research Funds for China Central Universities(DUT22LAB608 and DUT20RC(3)030)+1 种基金Liaoning Binhai Laboratory(LBLB-2023-03)Key R&D Program of Shandong Province(2021CXGC010308).
文摘In photolithography,shortening the exposure wavelength from ultraviolet to extreme ultraviolet(EUV,13.5 nm)and soft X-ray region in terms of beyond EUV(BEUV,6.X nm)and water window X-ray(WWX,2.2–4.4 nm)is expected to further miniaturize the technology node down to sub-5 nm level.However,the absorption ability of molecules in these ranges,especially WWX region,is unknown,which should be very important for the utilization of energy.Herein,the molar absorption cross sections of different elements at 2.4 nm of WWX were firstly calculated and compared with the wavelengths of 13.5 nm and 6.7 nm.Based on the absorption cross sections in these ranges and density estimation results from the density-functional theory calculation,the linear absorption coefficients of typical resist materials,including metal-oxy clusters,organic small molecules,polymers,and photoacid generators(PAGs),are evaluated.The analysis suggests that the Zn cluster has higher absorption in BEUV,whereas the Sn cluster has higher absorption in WWX.Doping PAGs with high EUV absorption atoms improves chemically amplified photoresist(CAR)polymer absorption performance.However,for WWX,it is necessary to introduce an absorption layer containing high WWX absorption elements such as Zr,Sn,and Hf to increase the WWX absorption.
基金National Natural Science Foundation of China(No.51705545)。
文摘To minimize the calculation errors in the sound absorption coefficient resulting from inaccurate measurements of flow resistivity,a simple method for determining the sound absorption coefficient of soundabsorbing materials is proposed.Firstly,the sound absorption coefficients of a fibrous sound-absorbing material are measured at two different frequencies using the impedance tube method.Secondly,utilizing the empirical formulas for the wavenumber and acoustic impedance in the fibrous material,the flow resistivity and porosity of the sound-absorbing materials are calculated using the MATLAB cycle program.Thirdly,based on the values obtained through reverse calculations,the sound absorption coefficient,the real and the imaginary parts of the acoustic impedance of the sound-absorbing material at different frequencies are theoretically computed.Finally,the accuracy of these theoretical calculations is verified through experiments.The experimental results indicate that the calculated values are basically consistent with the measured values,demonstrating the feasibility and reliability of this method.
基金financially supported by National Key Research and Development Program of China (No.2021YFD1800900)National Natural Science Foundation of China (No.82073790)+2 种基金Special Fund for Youth Team of Southwest University (No.SWUXJLJ202306)Chongqing Science and Technology Commission (Nos.CSTB2022TIAD-LUX0001,CSTB2023NSCQ-JQX0002)Innovation Research 2035 Pilot Plan of Southwest University (No.SWUXDPY22007)。
文摘Chitosan(CS),a natural polymer derived from chitin found in the exoskeletons of crustaceans,has garnered significant interest in the pharmaceutical field due to its unique properties,including biocompatibility and biodegradability.In recent years,various studies have reported that CS can affect drug bioavailability,and interestingly,it works as an oral absorption enhancer and inhibitor.This review offers an in-depth analysis of the mechanisms underlying such a phenomenon and supports its application as a pharmaceutical excipient.CS enhances oral drug absorption through various mechanisms,such as interaction with the intestinal mucosa,tight junction modulation,inhibition of efflux transporters,enzyme inhibition,solubility and stability enhancement,and complexation.On the other side,CS exhibits the ability to inhibit the absorption of certain drugs by adsorbing to lipids and sterols,modulating bile acids and gut microbiota,altering drug-cell interaction at the polar interface,and mucus-mediated entrapment and interference.Future potential pharmaceutical research in this field includes elucidating the underneath absorption relevant mechanisms,rational use in formulations as excipient,exploring functional CS derivatives,and developing CS-based drug delivery systems.This comprehensive review highlights CS's versatile and significant role in enhancing and inhibiting oral drug absorption,providing insights into the complexities of drug delivery and the potential of CS to improve therapeutic outcomes.
文摘Using the pulp of Annona squamosa L.as the raw material,polysaccharides were extracted using ultrasonicassisted hot water extraction,with polysaccharide yield as the response variable.The effects of four factors on extraction efficiency were investigated,and the extraction process was optimized using an orthogonal experimental design.The monosaccharide composition of the polysaccharides was analyzed using ion chromatography(IC).The antioxidant activity was evaluated through DPPH radical scavenging,hydroxyl radical(·OH)scavenging,and ferric reducing antioxidant power(FRAP)assays.Additionally,Franz diffusion cells were used to conduct in vitro transdermal absorption experiments,measuring cumulative permeation and calculating permeation kinetics parameters.The results showed that under optimized extraction conditions,the polysaccharide yield was 50.57%±0.02%.Ion chromatography analysis revealed that the main monosaccharide components were arabinose(0.6%),glucose(40.5%),and fructose(58.9%).Antioxidant evaluation indicated that with the addition of 80μL of the extract,the DPPH radical scavenging rate reached 94.13%±0.81%;with 600μL,the hydroxyl radical scavenging rate was 93.33%±0.92%,and the FRAP value was(38.07±1.30)mmol/L.Transdermal absorption experiments demonstrated that the skin retention rates of the polysaccharide aqueous extract at 75%and 100%concentrations were 4.65%±1.52%and 12.37%±2.14%,respectively,with 12 h cumulative permeation rates of 57.43%±1.08%and 74.24%±0.74%.Kinetic analysis of transdermal absorption showed that the process followed zero-order kinetics,indicating a constant release rate under steady-state conditions,consistent with Fick’s diffusion law.This study systematically combined optimization of polysaccharide aqueous extraction,monosaccharide composition analysis,antioxidant activity evaluation,and transdermal permeation performance analysis.It revealed the bioactive properties and potential applications of Annona squamosa L.polysaccharides,particularly in the fields of antioxidant activity and transdermal permeation.The findings provide essential data to support the development of functional products based on Annona squamosa L.polysaccharides.
基金support provided by the Center for Fabrication and Application of Electronic Materials at Dokuz Eylül University,Türkiye。
文摘Biochar and biochar composites are versatile materials that can be used in many applications.In this study,biochar was prepared from sawdust and combined with the yttrium iron garnet(YIG)nanocrystal to investigate the shielding effectiveness of the composite structure.Firstly,the effect of the pyrolysis temperature on the shielding effectiveness of biochar was investigated.Secondly,biochars combined with YIG nanocrystals with different contents and shielding effectiveness of the composites were investigated.The electromagnetic effectiveness of the samples was investigated within the X band(8-12 GHz).The findings indicate that biochar demonstrates enhanced absorption properties with elevated pyrolysis temperatures.Biochars demonstrated an approximate 40 d B shielding effectiveness,while YIG exhibited approximately 7 d B,corresponding to absorption at 8 GHz.However,the combination of biochar and YIG exhibited exceptional absorption,reaching 67.12 d B at 8 GHz.
基金supported by the National Natural Science Foundation of China(Grant Nos.U2032136 and U2241288)the Shaanxi Fundamental Science Research Project for Mathematics and Physics(Grant No.23JSY012)。
文摘We present a solid 226 nm deep ultraviolet laser system pumped by a Nd:YAG laser.A diamond Raman laser with a 1485 nm wavelength was generated up to 2.53 mJ pumped by a 9.7 mJ 1064 nm laser,which is the highest pulse energy of a second Stokes diamond Raman laser pumped by a 1064 nm laser as we know.Then,the Raman laser is mixed with the frequency-quadrupled 1064 nm laser to produce the 226 nm laser.The maximum output pulse energy at 226 nm reaches 0.49 mJ.The overall conversion efficiency from1064 to 226 nm is up to 1.14%,which is significantly higher than conventional optical parametric oscillator technology for the generation of 226 nm laser.The 226 nm laser system has been used in a laser-induced fluorescence(LIF)experiment of oxygen two-photon to demonstrate its potential for LIF measurements.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFC3005603-01)the Natural Science Foundation Science of Anhui Province(Grant No.2308085US02).
文摘Hydraulic asphalt concrete(HAC)has been increasingly employed as an appropriate impervious structure in hydraulic and hydropower engineering.However,asphalt mortar,usually seen as the matrix of HAC composite,is particularly prone to damage under combined stress and seepage interactions,and the mesoscale investigations on the damage-seepage coupling behavior of HAC under complex stress states remain limited.This research develops a numerical three-dimensional mesoscale model composed of asphalt mortar and polyhedral aggregate to investigate the stress-damage-seepage coupling behavior in HAC.In this model,asphalt mortar yields the viscoelastic continuum damage law and aggregate obeys the Mazars’elastic-brittle damage law;simultaneously,the effective permeability coefficient of asphalt mortar is assumed to follow an exponential function of damage.The predicted deviatoric stress-strain and hydraulic gradient-seepage curves both are in good agreement with the reported experimental results,which shows the proposed model is valid and reasonable.The simulated results indicate that the damaged asphalt mortar can induce localized areas of high permeability,which in turn affects the overall impervious performance of HAC.
基金the Postdoctoral Science Foundation Funded Project of China with grant No.2021M701687Introduction and Education Plan for Young Innovative Talents in Colleges and Universities of Shandong Province.
文摘UHMWPE(Ultra-High Molecular Weight Polyethylene)plain-weave fabric,characterized by its lightweight and high-strength properties,is widely used in protective equipment such as bulletproof vests and stab-resistant vests,serving as a key material for enhancing protective performance.This study systematically investigates the influence mechanism of interfacial properties on the energy absorption characteristics of UHMWPE-based protective structures through multi-scale experiments and numerical simulations,and establishes a cross-scale design methodology.Innovatively,an orthotropic constitutive model incorporating dynamic friction coefficients is constructed,combined with a modified Johnson-Cook failure criterion,to achieve high-precision simulation of the entire ballistic impact process(error<3.5%).Additionally,a friction field prediction model considering strain rate effects is developed,and the friction evolution laws of UHMWPE and Para-aramid(Kevlar)fabrics under strain rates of 10^(−3) and 10^(−4) s^(−1) are obtained through MTS pull-out tests.The results show that:(1)there exists a critical yarn-yarn friction coefficient(μ=0.2);exceeding this value leads to a 19%reduction in energy absorption capacity,while viscous interfaces increase the energy dissipation peak by 16%;(2)UHMWPE shows kinetically-dominated absorption(58%)with high rate but high load,increasing damage risk.Para-aramid has friction-dominated absorption(53%)with a lower rate but stable load.Hybrid fabrics use potential-dominated absorption(49%)at a moderate rate,balancing stability and protection.(3)3–5 layers of UHMWPE fabric yield optimal cost-effectiveness,with the unit cost reduction rate of the HS+5U scheme reaching 2.74 m/(s·$),which is 91%higher than that of the hybrid scheme.(4)For HS+5U(5-ply UHMWPE),V50 is 520 m/s,meeting primary protection requirement.For hybrid solutions with U/K≥3(e.g.,HS+6U+2K),V50 reaches 580 m/s(≥540 m/s),satisfying advanced protection requirement.This research provides critical references for the design of flexible protective structures and their engineering applications.
基金supported by the National Natural Science Foundation of China(U23B20151 and 52171253).
文摘Although traditional gamma-gamma density(GGD)logging technology is widely utilized,its potential environmental risks have prompted the development of more environmentally friendly neutron-gamma density(NGD)logging technology.However,NGD measurements are influenced by both neutron and gamma radiations.In the logging environment,variations in the formation composition indicate different elemental compositions,which affect the neutron-gamma reaction cross-sections and gamma generation.Compared to traditional gamma sources such as Cs-137,these changes significantly affect the generation and transport of neutron-induced inelastic gamma rays and hinder accurate measurements.To address this,a novel method is proposed that incorporates the mass attenuation coefficient function to account for the effects of various lithologies and pore contents on gamma-ray attenuation,thereby achieving more accurate density measurements by clarifying the transport processes of inelastic gamma rays with varying energies and spatial distributions in varied logging environments.The proposed method avoids the complex correction of neutron transport and is verified through Monte Carlo simulations for its applicability across various lithologies and pore contents,demonstrating absolute density errors that are less than 0.02 g/cm^(3)in clean formations and indicating good accuracy.This study clarifies the NGD mechanism and provides theoretical guidance for the application of NGD logging methods.Further studies will be conducted on extreme environmental conditions and tool calibration.
基金supported by the National Natural Science Foundation of China(No.52436008)the Inner Mongolia Science and Technology Projects,China(Nos.JMRHZX20210003 and 2023YFCY0009)+3 种基金the Huaneng Group Co Ltd.,China(No.HNKJ23-H50)the National Natural Science Foundation of China(No.22408044)the China Postdoctoral Science Foundation(No.2024M761877)the National Key R&D Program of China(No.SQ2024YFD2200039)。
文摘The electromagnetic wave absorption of silicon carbide nanowires is improved by their uniform and diverse cross-structures.This study introduces a sustainable and high value-added method for synthesizing silicon carbide nanowires using lignite and waste silicon powder as raw materials through carbothermal reduction.The staggered structure of nanowires promotes the creation of interfacial polarization,impedance matching,and multiple loss mechanisms,leading to enhanced electromagnetic absorption performance.The silicon carbide nanowires demonstrate outstanding electromagnetic absorption capabilities with the minimum reflection loss of-48.09 d B at10.08 GHz and an effective absorption bandwidth(the reflection loss less than-10 d B)ranging from 8.54 to 16.68 GHz with a thickness of 2.17 mm.This research presents an innovative approach for utilizing solid waste in an environmentally friendly manner to produce broadband silicon carbide composite absorbers.
基金supported by the National Key R&D Program of China(Grant No.2019YFC1509703)the Tianjin Science and Technology Program Project(Grant No.23YFYSHZ00130)。
文摘Sandwich structures are widely favored for their lightweight,high strength and superior impact mitigation capabilities in blast mitigation and transportation safety applications.Their application in large-scale,high-energy rockfall protection remains limited due to their relatively low volumetric energy absorption efficiency and the complex fabrication processes of key energy-absorbing components.To address these limitations,this study proposes a novel sandwich structure incorporating mild steel tubes as core energy absorbers to efficiently mitigate highenergy rockfall impacts.A finite element model was developed in LS-DYNA to systematically investigate the deformation and energy absorption behaviors.Comprehensive parametric analyses were conducted to quantify the effects of key design variables,including tube wall thickness,tube spacing(number of tubes),and infill materials.The results demonstrate that increasing tube wall thickness significantly enhances ultimate energy absorption,with 12-mm-thick tubes absorbing 2.2 times more energy than 6-mm-thick tubes.Lateral constraints induced by adjacent tubes improve specific energy absorption per unit displacement by approximately 30%-45%.Furthermore,incorporating infill materials considerably enhances energy absorption,with aluminum foam infills achieving an 81%increase compared to empty tubes.Nevertheless,higher energy absorption capacity typically leads to greater peak impact forces,increasing the number of tubes offers a better balance between energy absorption and impact force,optimizing the structural performance.These findings provide valuable theoretical insights and practical guidelines for designing sandwich structures in civil and infrastructure engineering applications for effective rockfall protection.
基金supported by the Khalifa University of Science and Technology internal grants(Nos.2021-CIRA-109,2020-CIRA-007,and 2020-CIRA-024).
文摘Low-velocity impact tests are carried out to explore the energy absorption characteristics of bio-inspired lattices,mimicking the architecture of the marine sponge organism Euplectella aspergillum.These sea sponge-inspired lattice structures feature a square-grid 2D lattice with double diagonal bracings and are additively manufactured via digital light processing(DLP).The collapse strength and energy absorption capacity of sea sponge lattice structures are evaluated under various impact conditions and are compared to those of their constituent square-grid and double diagonal lattices.This study demonstrates that sea sponge lattices can achieve an 11-fold increase in energy absorption compared to the square-grid lattice,due to the stabilizing effect of the double diagonal bracings prompting the structure to collapse layer-bylayer under impact.By adjusting the thickness ratio in the sea sponge lattice,up to 76.7%increment in energy absorption is attained.It is also shown that sea-sponge lattices outperform well-established energy-absorbing materials of equal weight,such as hexagonal honeycombs,confirming their significant potential for impact mitigation.Additionally,this research highlights the enhancements in energy absorption achieved by adding a small amount(0.015 phr)of Multi-Walled Carbon Nanotubes(MWCNTs)to the photocurable resin,thus unlocking new possibilities for the design of innovative lightweight structures with multifunctional attributes.
基金the financial support by the Ningbo Key Research and Development Program(No.2022Z192)Jiangxi Provincial Major Science and Technology Project(No.20233AAE02007)+1 种基金the Key Research and Development Program of Zhejiang Province(No.2024C01157)the National Natural Science Foundation of China(No.52102370)。
文摘With the increasing requirements of electromagnetic wave(EMW)absorption,developing EMW absorbers with high-efficiency anti-corrosion performance which can be effectively applied in extreme corrosive environments is imperative and constitutes a hot issue in the current research.Herein,based on the composition modulation of ZrO_(2)and SiO_(2)layer,the dual-oxides confined carbonyl iron(CI@ZrO_(2)/SiO_(2))composite displays a minimum reflection loss(RLmin)of-48.58 dB@1.9 mm and an effective absorption bandwidth(EAB)of 7.62 GHz@1.6 mm.Besides,the CI@ZrO_(2)/SiO_(2)displays superior corrosion resistance with corrosion current density(i_(corr))of 8.62×10^(-7)A/cm^(2)and polarization resistance(Rp)of 3.64×10^(5)Ω.This work proposes a strategy to optimize the broadband EMW absorption properties as well as the mass production toward the corrosion resistance applications.
基金supported by ZJNSF LZ25E030006Zhejiang Provincial Key Research and Development Program(2024C01157)+2 种基金NSFC under Grant Nos.52473267 and 52401249the National Key Research and Development Program of China under Grant No.2021YFB3501504Zhejiang University Ningbo“Five in One”Campus Project(K-20213539)。
文摘Three-dimensional(3D)-printedgraphene aerogels hold promise for electromagneticwave absorption(EWA)engineering due to itsultralow density,outstanding electromagnetic dissipationwith the flexibility and precision of manufacturingstrategies.However,their high conductivitycauses severe impedance mismatch,limiting EWAperformance.3D printing requirements also constrainthe dielectric properties of printable grapheneinks,hindering the integration of high-performanceabsorbers with advanced manufacturing.This studyproposes a polyacrylic acid(PAA)gel-mediated3D porous graphene oxide(GO)aerogel multiscaleregulation strategy.Precise gel content control enablesdual-gradient tuning of the rheology(Benefitingdirect ink writing(DIW))and dielectric loss(Enhancing EWA)of GO/PAA composites and reduces aerogel density(6.9 mg cm^(-3)from28.2 mg cm^(-3)).Thermal reduction decomposes PAA into amorphous carbon nanoparticles anchored on reduced graphene oxide(rGO),enhancingimpedance matching and absorption via synergistic 0D/2D interfacial polarization and conductive loss.The optimized rGO/PAA aerogelachieves a minimum reflection loss(RL)of-39.86 dB at 2.5 mm and an effective absorption bandwidth(EAB)of 8.36 GHz(9.64-18 GHz)at3.2 mm.Combining DIW and this aerogel,we design a metamaterial absorber(MA)with dual material(dielectric loss)and structural gradients.This MA exhibits an ultrawide EAB of 14 GHz(4-18 GHz)with a total thickness of 7.8 mm.This work establishes a coupled design paradigmof“composition-structure-performance,”providing an engineerable solution for developing lightweight,broadband EWA materials.
基金Supported by the National Science and Technology Major Project of China(2022ZD0119005)the Natural Science Project of Shaanxi Province(2025JC-YBMS-754,2024JC-YBMS-539)。
文摘Reconfigurable array architecture has become an important hardware platform for edge-side deployment of convolutional neural networks due to their high parallelism and flexible programmability.However,traditional multi-branch convolutional networks suffer from computational redundancy,high memory access overhead,and inefficient branch fusion.Therefore,this paper proposes an adaptive multi-branch convolutional module(AMBC)that integrates software-hardware co-optimization.During training,the learnable fusion coefficients are introduced to enable adaptive fusion of multi-scale features,while in the inference phase,the multiple branches and their normalization parameters are merged with the fusion coefficients into a single 3×3 convolutional kernel through operator fusion.On the SIREA-288 reconfigurable platform,compared with unoptimized multi-branch networks,the proposed AMBC reduces external memory accesses by 47.91%and inference latency by 47.20%,achieving a 1.90×speedup.This approach maximizes the utilization of the reconfigurable logic while minimizing both reconfiguration and data-movement overheads in edge inference.
基金financially supported by the NNSF of China(Grant Nos.12074095,12374392,and 52403351)the Joint Guidance Project of the Natural Science Foundation of Heilongjiang Province(LH2023A012)。
文摘The development of multifunctional electromagnetic wave-absorbing materials is essential for next-generation flexible electronics and intelligent protection systems.Herein,a novel three-dimensional porous MXene-based film integrated with metallic nickel nanoparticles(Ni-PMF)is designed and synthesized with the potential to address the urgent need for multifunctional electromagnetic wave-absorbing materials in next-generation intelligent systems.By using polystyrene spheres as sacrificial templates,a hierarchical porous architecture is constructed to prevent MXene nanosheet restacking,extend electromagnetic wave propagation paths,and optimize impedance matching.Simultaneously,uniformly distributed Ni nanoparticles introduce abundant heterogeneous interfaces,enhancing interfacial polarization and magnetic loss,which significantly improve electromagnetic wave attenuation.The Ni-PMF film achieves a minimum reflection loss of–64.7 d B and a broad effective absorption bandwidth of 7.2 GHz,covering the full Ku-band and outperforming most reported MXene thin film absorbers.In addition to superior electromagnetic wave absorption,the film demonstrates excellent electrothermal conversion and flexible strain-sensing capabilities,enabling integrated protection and real-time sensing functions.This multifunctional material offers promising potential for next-generation smart flexible electronic systems.
基金supported by The Youth Innovation Team of Shaanxi Universities and The Innovation and Entrepreneurship Team of Special Support Program for‘Sanqin’Talentthe Special Support Program for High-level Talents of Shaanxi Province(No.2020-44)the China Postdoctoral Science Foundation(2022M723884)。
文摘Ferrite-carbon composites effectively absorb electromagnetic(EM)waves via coupled mechanisms.However,the dynamic evolution of intrinsic polarization and magnetic loss mechanisms following interfacial coupling has long been overlooked,impeding broadening of the ultra-broadband EM wave absorption performance in heterostructures.Herein,via surface ligand modulation,in situ growth of 0D Fe_(3)O_(4)quantum dots(QDs)on the surface of 1D carbon nanotubes triggers grain boundary coupling.The energy rebalancing effect at the interface induces an extreme charge rearrangement within the Fe_(3)O_(4)QDs.This rearrangement enhances dipole orientation hysteresis and charge accumulation,resulting in charge and interfacial polarization losses.Meanwhile,for subcritical Fe_(3)O_(4)QDs,short-range magnetic resonance and magnetic exchange-triggered magnetic resonance transfer synergistically enhance the magnetic loss.Through charge rearrangement/magnetic resonance induced by0D/1D grain boundary coupling,an effective bandwidth of nearly 10 GHz is achieved at a minimal thickness of 2 mm,covering the X and Ku bands.This strategy provides an effective paradigm and novel theoretical insights for ultra-broadband electromagnetic wave absorption applications.
基金supported by the Zhenjiang Key R&D Plan(GY2021009)Lianyungang City Major Technology Breakthrough(CGJBGS2104)+2 种基金National Natural Science Foundation of China under Grant(12302456)National Key Laboratory Foundation of Science and Technology on Materials under Shock and Impact under Grant(6142902241601)China Postdoctoral Science Foundation under Grants(2025M774217)。
文摘Flexible materials play a crucial role in protecting against behind armour blunt trauma(BABT).However,their compliance complicates the understanding of failure mechanisms and energy absorption.This study used a combined experimental and numerical approach to investigate the response and failure modes of a flexible ultra-high-molecular-weight polyethylene(UHMWPE)foam protective sandwich structure(UFPSS)under low-velocity impact(LVI).A finite element(FE)model,accounting for nonlinear large deformation and strain-rate-dependent material behavior,was developed for a woven-UFPSS(featuring a plain-woven fabric structure)subjected to a 50 J impact.Experimental and numerical results showed strong agreement in peak force(error<5%),maximum displacement(error<6%),and buffer time(error<8%).The impact's kinetic energy was mainly converted into internal energy of the fabric and foam materials(~50%),viscous dissipation in the foam core(12%-15%),frictional work at the contact interfaces(5%-6%),and work by the pneumatic fixture clamping force(~38%).This study provides the first investigation of the LVI performance of sandwich structures with all soft material layers,offering significant insights for the application of compliant materials in protective fields.
基金financially supported by the National Key R&D Program of China(2024YFC3012700)National Natural Science Foundation of China(12302499)+1 种基金Key Laboratory of Mountain Hazards and Engineering Resilience,Chinese Academy of Sciences(KLMHER-Z17,KLMHER-T07)National Natural Science Foundation of Fujian Province(Grant No.2024J08074).
文摘Frozen moraine soils are widely distributed across the Tianshan Mountains,the Qinghai-Tibetan Plateau,and other high-altitude regions.Engineering activities,particularly blasting,often induce degradation of the soil microstructure,compromising its mechanical integrity and increasing the risk of slope instability and rainfall-triggered debris flows-posing serious threats to infrastructure in cold regions.Previous studies have largely treated frozen soils as homogeneous continua,thereby overlooking key micro-scale processes such as ice-soil interaction,microcrack propagation,and particle breakage.In this study,the dynamic mechanical behavior and microstructural damage mechanisms of frozen moraine soil were systematically investigated under varying temperatures(−5℃,−15℃,and−25℃)and strain rates(50 s^(-1),70 s^(-1),and 90 s^(-1)).Results reveal that both temperature and strain rate significantly influence the dynamic stress-strain response.Energy absorption exhibits a three-stage pattern of increase,stabilization,and decline.At−25℃,increased ice brittleness reduces the peak energy absorption efficiency under impact.To capture the observed nonlinear behavior,a damage-based constitutive model was developed,incorporating coupled effects of impact-induced microcracking,ice-soil interfacial debonding,and particle fracture.The stochastic evolution of interfacial debonding and grain breakage was described using a Weibull statistical framework,linking microstructural deterioration to macroscopic response.The model shows strong agreement with experimental data and accurately simulates key parameters such as peak stress and energy absorption.These findings enhance the understanding of dynamic damage mechanisms in frozen soils and offer a computational tool for the safety assessment and hazard mitigation of engineering structures in cold,high-altitude environments.
