Elemental calcium plays an important role in human physiology. In order to study the relationship between Ca-intake, Ca-chemical formulation, and Ca-absorptivity, a balance experiment using a ^(41)Ca tracer technique ...Elemental calcium plays an important role in human physiology. In order to study the relationship between Ca-intake, Ca-chemical formulation, and Ca-absorptivity, a balance experiment using a ^(41)Ca tracer technique in SD rats was conducted to measure the endogenous fecal calcium and true absorption of calcium. Apparent absorption of calcium was measured as a control to the endogenous calcium labeling experiment. These results show that by using ^(41)Ca labeled endogenous calcium in vivo, researchers could obtain the true calcium absorption data without extrinsic labeling. Therefore, the method was not affected by the chemical structure or type of calcium supplement and might be used in evaluating the absorptivity of marketed calcium supplements.展开更多
When the thermal environment is under heated conditions, short-wavelength solar radiation shows a strong influence on the human body and the heat is accumulated in the human body. In order to demonstrate the effect of...When the thermal environment is under heated conditions, short-wavelength solar radiation shows a strong influence on the human body and the heat is accumulated in the human body. In order to demonstrate the effect of the short-wavelength solar radiation absorptivity of clothing on physiological temperature in an outdoor space, the relationship between the thermal environment evaluation index, ETFe, and the thermal sensory perceptions of the human body was investigated. A significant temperature difference of 2.7°C was shown for an ETFe that was thermally neutral (neither hot nor cold). The effect of short-wavelength solar radiation absorptivity was strongly apparent in ETFe when direct solar radiation was strong and in warmer outdoor spaces. In an outdoor space where the effect of the sky factor and albedo was strong, the setting of the short-wavelength solar radiation absorptivity was demonstrated to greatly impact the estimation of perceived and physiological temperature. When interviewing subjects on clothing in an outdoor space, it is essential to obtain the hue of clothing.展开更多
The mathematical equations of the effective percentage of a complexant and ite complex-ratio with a metal have been developed by means of the β-correction pinciple. From a real absorbance of the chelate produced,its ...The mathematical equations of the effective percentage of a complexant and ite complex-ratio with a metal have been developed by means of the β-correction pinciple. From a real absorbance of the chelate produced,its true absorptivity can be determined accurately. The β-correction spectrophotometry was studied for the determinations of the desired parameters above, using the reaction of lead with Eriochrome Black T(EBT) at pll 8.2. The results show that the analytical sensitivity and precision by β-correction method are both mucb higher than those by the single wavelength method, the complex-ratio of Pb(Ⅱ) with EBT equals to 1:4 and the true molar absorptivity of Pb(EBT)4 chelate at 550 nm is 3.52,104 L.mol-1.cm-1.展开更多
Choosing two different elements of rare earth, the absorptivity of them on copper and its alloys were researched from the category of rare earth, melting point, adding methods, casting temperature, time of heat preser...Choosing two different elements of rare earth, the absorptivity of them on copper and its alloys were researched from the category of rare earth, melting point, adding methods, casting temperature, time of heat preservation, quantity of rare earth additives etc. The laws of affecting the absorptivity are found through the research. The distributing of rare earth, existent state and the formed compounds on copper and its alloys were observed in the casting state. The absorptivities of rare earth on copper and its alloys were analyzed.展开更多
The molar absorption coefficients of each of 14 kinds of amino acids were determined by the spectrophotometric method, and the mean molar absorption coefficients of 37 different mixtures of each with amino acid compos...The molar absorption coefficients of each of 14 kinds of amino acids were determined by the spectrophotometric method, and the mean molar absorption coefficients of 37 different mixtures of each with amino acid composition exactly equivalent to that of the peptide chain of the corresponding lipopeptide were determined based on calculation or experimental. The significance of the results is that the mean molar absorption coefficients strongly demonstrate the regular patterns, though different amino acids bear quite different molar absorption coefficients.展开更多
Background:Traditional Chinese medicine involves complex ingredients and mixtures of ingredients that often exhibit low bioavailability,and excipients are often lacking to increase the absorption-enhancing effects.Thi...Background:Traditional Chinese medicine involves complex ingredients and mixtures of ingredients that often exhibit low bioavailability,and excipients are often lacking to increase the absorption-enhancing effects.This study modified the generation 4 polyamidoamine dendrimer with polyethylene glycol of different molecular weights(5000,2000,1000)to form a series of polyamidoamine-co-polyethylene glycol(PAMAM-co-PEG)as a novel class of oral absorption enhancers.Evodiamine,the major alkaloid found in the traditional Chinese medicine Wu Zhu Yu(Fructus Evodiae),was used as a model drug to verify the absorption-enhancing effects and the safety of this alkaloid.Methods:This study utilized the solubility determination method documented in the Pharmacopoeia of the People’s Republic of China(2015 edition)and the D0 values recommended in the US FDA guidelines to comprehensively evaluate the solubility of evodiamine.The permeability of evodiamine was assessed using the apparent permeability coefficient in experiments based on in vitro cell models.Multiple aspects of the biological safety of PAMAM-co-PEG were explored using the MTT assay,LDH assay,and total protein release of the rat intestinal tract.Moreover,the absorption-enhancing effects of PAMAM-co-PEG at different molecular weights on evodiamine were verified via the use of in vitro cell models and in vivo intestinal loop circulation experiments with rats.Results:Evodiamine exhibited low solubility and permeability and was classified into class IV compounds using the biopharmaceutical classification system.PAMAM-co-PEG 2000 demonstrated improvement in the biosafety and absorption-enhancement effect of evodiamine at a specific concentration.This study showed that 0.05%(w/v)of PAMAM-co-PEG 2000 increased the cumulative penetration of evodiamine via cell transport by 1.32 times,and 0.10%(w/v)of PAMAM-co-PEG 2000 increased the area under curve value of evodiamine by 1.31 times.Conclusion:Evodiamine possesses low solubility and permeability and leads to poor oral bioavailability and a certain degree of cytotoxicity.PAMAM-co-PEG 2000 was found to be a potentially safe and efficient oral absorption enhancer.The results of this study might create a foundation for the development of novel excipients suitable for the complex active ingredients of traditional Chinese medicine.展开更多
Background:Excessive use of inorganic trace minerals(ITMs)in swine production leads to high fecal mineral excretion and environmental risks,while most studies on organic trace minerals(OTMs)focus on single elements,wi...Background:Excessive use of inorganic trace minerals(ITMs)in swine production leads to high fecal mineral excretion and environmental risks,while most studies on organic trace minerals(OTMs)focus on single elements,with limited data on the synergistic effects and molecular mechanisms of combined OTMs(Fe,Cu,Mn,Zn)in growing-finishing pigs.Methods:This study aimed to investigate the effects of graded levels of micromineral proteinates(combined OTMs)on growth performance,mineral metabolism,and mRNA expression of mineral regulatory proteins.A total of 360 crossbred Duroc×Landrace×Large White pigs(initial body weight 47.1±4.8 kg)were randomly assigned to 6 dietary treatments:basal diet without microminerals(CON),basal diet with ITMs at commercially recommended levels(IT),and basal diets with 15%(OT 15%),25%(OT 25%),35%(OT 35%)commercially recommended levels(CRL)of combined micromineral proteinates.After a 70-day feeding trial,samples were analyzed using ICP-OES,ELISA,and RT-qPCR.Results:Results showed that reduced levels(15-35%CRL)of micromineral proteinates did not significantly affect average daily gain,average daily feed intake,or feed conversion ratio(gain-to-feed ratio)compared to IT(P>0.05),but significantly increased plasma Cu(1.73-1.83μg/mL)and Zn(1.72-1.97μg/mL)concentrations(P<0.05)and elevated activities of Cu/Zn-superoxide dismutase(32.9-35.9 U/L)and manganese superoxide dismutase(20.5-24.1 U/L)compared to CON(P<0.05),with no significant differences from IT(P>0.05).Fecal excretion of Fe,Cu,Mn,and Zn was significantly reduced by 35-50%in OT 15%-OT 35%groups compared to IT(P<0.05).OT 25%group exhibited the highest apparent absorptivity of Fe(38.5%),Cu(27.8%),and Zn(42.4%)(P<0.05),which was associated with significantly regulated mRNA expression of mineral regulatory proteins:upregulated DMT1,FPN1,ZIP4,and MT1A in the duodenum,and modulated HAMP,ATP7B,ZIP14,and ZnT1 in the liver(P<0.05).Conclusion:In conclusion,dietary supplementation with 25%CRL or less of combined micromineral proteinates can fully meet the nutritional needs of growing-finishing pigs,improve mineral absorptivity,and reduce fecal mineral excretion by regulating intestinal and hepatic mineral transport and homeostatic proteins,providing a sustainable alternative to high-dose ITMs.展开更多
With the rapid development of modern electronic technology,the demand for high-performance microwave absorption materials has increased dramatically.In order to meet this demand,the electrospinning of FeNiCo/carbon na...With the rapid development of modern electronic technology,the demand for high-performance microwave absorption materials has increased dramatically.In order to meet this demand,the electrospinning of FeNiCo/carbon nanofiber(FeNiCo/CNF)composites with excellent microwave absorption properties was developed,and their potential as high frequency microwave absorption materials was evaluated.Experiment showed that FeNiCo/CNFs achieve a minimum reflection loss(RL_(min))of−55.5 dB with a matching thickness of only 1.6 mm.Microstructure analysis and electromagnetic parameter testing showed that the excellent microwave absorbing properties were mainly due to the combined effect of the network structure of carbon nanofibers and the FeNiCo alloy.This interaction promotes multiple reflections and the efficient absorption of microwaves.Computer simulation also showed that the FeNiCo/CNF composites produce an excellent radar cross-section reduction in typical radar operating frequency bands,which validates their potential application in stealth technology.This is a new concept in the development of high-performance microwave absorption materials.展开更多
The development of materials with excellent microwave absorption(MWA)and electromagnetic interference(EMI)shielding performances has currently received attention.Herein,mesophase pitch-based carbon foam(MPCF)with 3D i...The development of materials with excellent microwave absorption(MWA)and electromagnetic interference(EMI)shielding performances has currently received attention.Herein,mesophase pitch-based carbon foam(MPCF)with 3D interconnected pore structure was prepared through the high pressure pyrolysis of mesophase coal tar pitch.It is found that the 3D interconnected cellular pores of MPCF facilitate multiple reflections of electromagnetic waves,which results in the minimum reflection loss(RLmin)value of MPCF reaches-37.84 dB with the effective absorption bandwidth(EAB)of 5.44 GHz at a thickness of 2.70 mm,and the total average electromagnetic shielding effectiveness(SE_(T))under 3.00 mm thickness achieves 26.52 dB in X-band.Subsequently,MPCF is activated by KOH to obtain activated carbon foam(A-MPCF).The average SE_(T)of A-MPCF achieves 103.00 dB for abundant nanopores on the pore cell walls,which leads to a transition from the multiple reflections of electromagnetic waves on the walls to diffuse reflection.Unfortunately,the reflection coefficient(R)of A-MPCF increases from 0.78 to 0.90.To reduce the R value,Fe_(3)O_(4)/A-MPCF was fabricated via the in situ growth of nano Fe_(3)O_(4)on A-MPCF.Consequently,the R value of Fe_(3)O_(4)/A-MPCF was reduced from 0.90 to 0.74,whereas the MWA performance was only slightly decreased.This work proposes a simple strategy for simultaneously adjusting MWA and EMI shielding performances of materials.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
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
Environmental pollution,energy consumption,and greenhouse gas emissions are critical global issues.To address these challenges,optimizing skimmer coatings is a major step in commercializing cleaning oil stains.This re...Environmental pollution,energy consumption,and greenhouse gas emissions are critical global issues.To address these challenges,optimizing skimmer coatings is a major step in commercializing cleaning oil stains.This research presents a novel approach to creating and refining oil absorbent coatings,introducing a unique oil spill removal skimmer enhanced with a super hydrophobic polyaniline(PANI)nanofiber coating.The goal of this study was to improve oil absorption performance,increase the contact angle,lower drag,reduce energy consumption,achieve high desirability,and lower production costs.PANI treated with hydrochloric acid was a key focus as it resulted in higher porosity and smaller pore diameters,providing a larger surface area,which are crucial factors for boosting oil absorption and minimizing drag.To optimize optimal nanofiber morphology,PANI synthesized with methanesulfonic acid was first dedoped and then redoped with hydrochloric acid.After optimization,the most effective skimmer coating was achieved using a formulation consisting of 0.1%PANI,an ammonium persulfate/aniline ratio of 0.4,and an acid/aniline ratio of 9.689,along with redoped PANI nanofibers.The optimized skimmer exhibited a remarkable contact angle of 177.477°.The coating achieved drag reduction of 32%,oil absorption of 88.725%,a cost of$1.710,and a desirability rating of 78.5%.In this study,an optimized skimmer coat containing super hydrophobic coat-PANI nanofibers was fabricated.By enhancing contact angle and reducing drag,these coatings increased the skimmer performance by improving oil absorption and reducing fuel consumption.展开更多
The rapid advancement of 5G/6G communication and radar technology has exacerbated issues of electromagnetic wave(EMW)leakage,interference,and thermal management.Therefore,developing lightweight EMW absorbers that inte...The rapid advancement of 5G/6G communication and radar technology has exacerbated issues of electromagnetic wave(EMW)leakage,interference,and thermal management.Therefore,developing lightweight EMW absorbers that integrate strong absorption,broad bandwidth,and thermal stability is crucial.Herein,a 3D MXene sponge/NiFe@NC heterostructure with tunable pore architecture is constructed by pyrolyzing a polyurethane(PU)foam template uniformly coated with NiFe-decorated Ti_(3)C_(2)T_(x)MXene nanosheets.The resulting porous dielectric-magnetic network integrates interconnected MXene pathways with uniformly dispersed NiFe@NC nanoparticles,enabling a synergistic effect of dielectric-magnetic loss through conduction loss,dipole/interface polarization,and magnetic loss.Precise pore structure design enhances impedance matching and promotes multi-scattering and internal reflection of EMWs.Notably,an“EMW-pore matching”mechanism is proposed,whereby pore size governs the impedance matching at specific frequencies,enabling tunable absorption performance.The optimized absorber achieves a reflection loss(RL)of-67.84 dB,while radar cross-section(RCS)simulations confirm its exceptional attenuation and stealth potential.Additionally,the 3D skeleton derived from PU foam confers remarkable thermal resistance and flame retardancy.This pore-regulation strategy provides a scalable route to designing lightweight,broadband,and thermally stable EMW absorbers for next-generation communication and stealth applications.展开更多
The ultracold neutron(UCN)transport code,MCUCN,designed initially for simulating UCN transportation from a solid deuterium(SD_2)source and neutron electric dipole moment experiments,could not simulate UCN storage and ...The ultracold neutron(UCN)transport code,MCUCN,designed initially for simulating UCN transportation from a solid deuterium(SD_2)source and neutron electric dipole moment experiments,could not simulate UCN storage and transportation in a superfluid^(4)He(SFHe,He-Ⅱ)source accurately.This limitation arose from the absence of an^(4)He upscattering mechanism and the absorption of^(3)He.And the provided source energy distribution in MCUCN is different from that in SFHe source.This study introduced enhancements to MCUCN to address these constraints,explicitly incorporating the^(4)He upscattering effect,the absorption of^(3)He,the loss caused by impurities on converter wall,UCN source energy distribution in SFHe,and the transmission through negative optical potential.Additionally,a Python-based visualization code for intermediate states and results was developed.To validate these enhancements,we systematically compared the simulation results of the Lujan Center Mark3 UCN system by MCUCN and the improved MCUCN code(iMCUCN)with UCNtransport simulations.Additionally,we compared the results of the SUN1 system simulated by MCUCN and iMCUCN with measurement results.The study demonstrates that iMCUCN effectively simulates the storage and transportation of ultracold neutrons in He-Ⅱ.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
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
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
This study addresses the energy-intensive challenge of small-scale biogas upgrading by optimizing a chemical absorption process employing methyl diethanolamine(MDEA).Focusing on a typical distributed application of 30...This study addresses the energy-intensive challenge of small-scale biogas upgrading by optimizing a chemical absorption process employing methyl diethanolamine(MDEA).Focusing on a typical distributed application of 300 Nm^(3)/d,we developed an integrated simulation-optimization framework using Aspen HYSYS 14.0 to systematically evaluate the effects of critical operating parameters—absorption pressure,MDEA concentration,flow rate,temperature,number of trays,and reboiler duty—on methane purity and energy consumption.The key finding is the identification of an optimal parameter set:absorption pressure of 1200 kPa,MDEA concentration of 20mol%,lean flow rate of 2.5 kmol/h,temperature of 298.15 K,20 absorber trays,10 regenerator trays,and a reboiler duty of 4 kW,which enabled the product gas to achieve a high CH4 concentration of 97mol%,compliant with pipeline standards.A detailed energy consumption analysis revealed that the reboiler is the most energy-intensive unit,accounting for 75.40%of the total 5.29 kW energy consumption,followed by the gas compressor(23.38%).The specific energy consumption for CH4 recovery and the Energy Consumption Index(ECI)were quantified at 0.8852 kWh/kg CH_(4)and 6.82,respectively.This work provides a validated optimization strategy and critical energy breakdown,offering practical guidance for enhancing the technical and economic viability of small-scale,centralized biogas purification systems.展开更多
Coherent perfect absorption(CPA)and coherent perfect transmission(CPT)are two extreme states arising from the manipulation of optical fields.Generally,CPA and CPT occur under different input-field phases.Therefore,we ...Coherent perfect absorption(CPA)and coherent perfect transmission(CPT)are two extreme states arising from the manipulation of optical fields.Generally,CPA and CPT occur under different input-field phases.Therefore,we propose a scheme to realize an all-optical switch based on phase-dependent CPA–CPT conversion.In our proposal,the CPT state and the CPA state are treated as the on state and the off state,respectively.Consequently,the efficiency of this all-optical switch can reach the maximum value of 1.With the introduction of an incoherent pump field,the CPA state can be achieved under a weaker input probe field or can be converted into a CPT state.The results show that the optical switch can operate with weaker fields and can be further optimized by the application of an incoherent field.展开更多
Negative Poisson’s ratio materials and structures exhibit lateral expansion under tensile loading,demonstrating significant mechanical advantages over conventional materials.This study systematically investigated thr...Negative Poisson’s ratio materials and structures exhibit lateral expansion under tensile loading,demonstrating significant mechanical advantages over conventional materials.This study systematically investigated three typical two-dimensional negative Poisson’s ratio metamaterial structures(Concave honeycomb,Anti-chiral,and Anti-chiral concave honeycomb hybrid structures)through both experimental tests and numerical analysis.The test specimens were fabricated using selective laser melting(SLM)additive manufacturing technology,and the experimental test was conducted with the use of a DIC strain measurement system.The numerical studies were performed considering both static tensile loading and dynamic impact loading with different strain rates.The deformation behaviors,failure process,negative Poisson’s ratio effects,and energy absorption capacity of the three different metamaterial structures are systematically investigated,and the associated mechanical mechanisms are thoroughly revealed.Results and findings of this work could provide valuable guidance for the engineering design and application of negative Poisson’s ratio metamaterials and structures.展开更多
基金supported by the National Nature Science Foundation of China(No.11375272)
文摘Elemental calcium plays an important role in human physiology. In order to study the relationship between Ca-intake, Ca-chemical formulation, and Ca-absorptivity, a balance experiment using a ^(41)Ca tracer technique in SD rats was conducted to measure the endogenous fecal calcium and true absorption of calcium. Apparent absorption of calcium was measured as a control to the endogenous calcium labeling experiment. These results show that by using ^(41)Ca labeled endogenous calcium in vivo, researchers could obtain the true calcium absorption data without extrinsic labeling. Therefore, the method was not affected by the chemical structure or type of calcium supplement and might be used in evaluating the absorptivity of marketed calcium supplements.
文摘When the thermal environment is under heated conditions, short-wavelength solar radiation shows a strong influence on the human body and the heat is accumulated in the human body. In order to demonstrate the effect of the short-wavelength solar radiation absorptivity of clothing on physiological temperature in an outdoor space, the relationship between the thermal environment evaluation index, ETFe, and the thermal sensory perceptions of the human body was investigated. A significant temperature difference of 2.7°C was shown for an ETFe that was thermally neutral (neither hot nor cold). The effect of short-wavelength solar radiation absorptivity was strongly apparent in ETFe when direct solar radiation was strong and in warmer outdoor spaces. In an outdoor space where the effect of the sky factor and albedo was strong, the setting of the short-wavelength solar radiation absorptivity was demonstrated to greatly impact the estimation of perceived and physiological temperature. When interviewing subjects on clothing in an outdoor space, it is essential to obtain the hue of clothing.
文摘The mathematical equations of the effective percentage of a complexant and ite complex-ratio with a metal have been developed by means of the β-correction pinciple. From a real absorbance of the chelate produced,its true absorptivity can be determined accurately. The β-correction spectrophotometry was studied for the determinations of the desired parameters above, using the reaction of lead with Eriochrome Black T(EBT) at pll 8.2. The results show that the analytical sensitivity and precision by β-correction method are both mucb higher than those by the single wavelength method, the complex-ratio of Pb(Ⅱ) with EBT equals to 1:4 and the true molar absorptivity of Pb(EBT)4 chelate at 550 nm is 3.52,104 L.mol-1.cm-1.
文摘Choosing two different elements of rare earth, the absorptivity of them on copper and its alloys were researched from the category of rare earth, melting point, adding methods, casting temperature, time of heat preservation, quantity of rare earth additives etc. The laws of affecting the absorptivity are found through the research. The distributing of rare earth, existent state and the formed compounds on copper and its alloys were observed in the casting state. The absorptivities of rare earth on copper and its alloys were analyzed.
基金This work was supported by the National Natural Science Foundation of China(No.50374038,50574040)Specialized Research Fund for the Doctoral Program of Higher Education(20030251002)+1 种基金Key Project of the Ministry of Education(03071)by the Department of Science and Technology Shanghai(045407017).
文摘The molar absorption coefficients of each of 14 kinds of amino acids were determined by the spectrophotometric method, and the mean molar absorption coefficients of 37 different mixtures of each with amino acid composition exactly equivalent to that of the peptide chain of the corresponding lipopeptide were determined based on calculation or experimental. The significance of the results is that the mean molar absorption coefficients strongly demonstrate the regular patterns, though different amino acids bear quite different molar absorption coefficients.
基金This research was funded by National Major Scientific and Technological Special Project for“Significant New Drugs Development”(No.2015ZX09501005)Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences(No.2016-I2M-1-012).
文摘Background:Traditional Chinese medicine involves complex ingredients and mixtures of ingredients that often exhibit low bioavailability,and excipients are often lacking to increase the absorption-enhancing effects.This study modified the generation 4 polyamidoamine dendrimer with polyethylene glycol of different molecular weights(5000,2000,1000)to form a series of polyamidoamine-co-polyethylene glycol(PAMAM-co-PEG)as a novel class of oral absorption enhancers.Evodiamine,the major alkaloid found in the traditional Chinese medicine Wu Zhu Yu(Fructus Evodiae),was used as a model drug to verify the absorption-enhancing effects and the safety of this alkaloid.Methods:This study utilized the solubility determination method documented in the Pharmacopoeia of the People’s Republic of China(2015 edition)and the D0 values recommended in the US FDA guidelines to comprehensively evaluate the solubility of evodiamine.The permeability of evodiamine was assessed using the apparent permeability coefficient in experiments based on in vitro cell models.Multiple aspects of the biological safety of PAMAM-co-PEG were explored using the MTT assay,LDH assay,and total protein release of the rat intestinal tract.Moreover,the absorption-enhancing effects of PAMAM-co-PEG at different molecular weights on evodiamine were verified via the use of in vitro cell models and in vivo intestinal loop circulation experiments with rats.Results:Evodiamine exhibited low solubility and permeability and was classified into class IV compounds using the biopharmaceutical classification system.PAMAM-co-PEG 2000 demonstrated improvement in the biosafety and absorption-enhancement effect of evodiamine at a specific concentration.This study showed that 0.05%(w/v)of PAMAM-co-PEG 2000 increased the cumulative penetration of evodiamine via cell transport by 1.32 times,and 0.10%(w/v)of PAMAM-co-PEG 2000 increased the area under curve value of evodiamine by 1.31 times.Conclusion:Evodiamine possesses low solubility and permeability and leads to poor oral bioavailability and a certain degree of cytotoxicity.PAMAM-co-PEG 2000 was found to be a potentially safe and efficient oral absorption enhancer.The results of this study might create a foundation for the development of novel excipients suitable for the complex active ingredients of traditional Chinese medicine.
基金financially supported by the Hainan Province Science and Technology Special Fund(Grant no:ZDYF2024XDNY187).
文摘Background:Excessive use of inorganic trace minerals(ITMs)in swine production leads to high fecal mineral excretion and environmental risks,while most studies on organic trace minerals(OTMs)focus on single elements,with limited data on the synergistic effects and molecular mechanisms of combined OTMs(Fe,Cu,Mn,Zn)in growing-finishing pigs.Methods:This study aimed to investigate the effects of graded levels of micromineral proteinates(combined OTMs)on growth performance,mineral metabolism,and mRNA expression of mineral regulatory proteins.A total of 360 crossbred Duroc×Landrace×Large White pigs(initial body weight 47.1±4.8 kg)were randomly assigned to 6 dietary treatments:basal diet without microminerals(CON),basal diet with ITMs at commercially recommended levels(IT),and basal diets with 15%(OT 15%),25%(OT 25%),35%(OT 35%)commercially recommended levels(CRL)of combined micromineral proteinates.After a 70-day feeding trial,samples were analyzed using ICP-OES,ELISA,and RT-qPCR.Results:Results showed that reduced levels(15-35%CRL)of micromineral proteinates did not significantly affect average daily gain,average daily feed intake,or feed conversion ratio(gain-to-feed ratio)compared to IT(P>0.05),but significantly increased plasma Cu(1.73-1.83μg/mL)and Zn(1.72-1.97μg/mL)concentrations(P<0.05)and elevated activities of Cu/Zn-superoxide dismutase(32.9-35.9 U/L)and manganese superoxide dismutase(20.5-24.1 U/L)compared to CON(P<0.05),with no significant differences from IT(P>0.05).Fecal excretion of Fe,Cu,Mn,and Zn was significantly reduced by 35-50%in OT 15%-OT 35%groups compared to IT(P<0.05).OT 25%group exhibited the highest apparent absorptivity of Fe(38.5%),Cu(27.8%),and Zn(42.4%)(P<0.05),which was associated with significantly regulated mRNA expression of mineral regulatory proteins:upregulated DMT1,FPN1,ZIP4,and MT1A in the duodenum,and modulated HAMP,ATP7B,ZIP14,and ZnT1 in the liver(P<0.05).Conclusion:In conclusion,dietary supplementation with 25%CRL or less of combined micromineral proteinates can fully meet the nutritional needs of growing-finishing pigs,improve mineral absorptivity,and reduce fecal mineral excretion by regulating intestinal and hepatic mineral transport and homeostatic proteins,providing a sustainable alternative to high-dose ITMs.
基金supported by the Natural Science Foundation of Shanxi Province(202203021212205)Shanxi Province Major Science and Technology Special Project‘Jiebang Guashuai’Project(202101120401008)+1 种基金National Natural Science Foundation of China(52371231)Key R&D Program of Shanxi Province(202302040201008).
文摘With the rapid development of modern electronic technology,the demand for high-performance microwave absorption materials has increased dramatically.In order to meet this demand,the electrospinning of FeNiCo/carbon nanofiber(FeNiCo/CNF)composites with excellent microwave absorption properties was developed,and their potential as high frequency microwave absorption materials was evaluated.Experiment showed that FeNiCo/CNFs achieve a minimum reflection loss(RL_(min))of−55.5 dB with a matching thickness of only 1.6 mm.Microstructure analysis and electromagnetic parameter testing showed that the excellent microwave absorbing properties were mainly due to the combined effect of the network structure of carbon nanofibers and the FeNiCo alloy.This interaction promotes multiple reflections and the efficient absorption of microwaves.Computer simulation also showed that the FeNiCo/CNF composites produce an excellent radar cross-section reduction in typical radar operating frequency bands,which validates their potential application in stealth technology.This is a new concept in the development of high-performance microwave absorption materials.
基金Supported by the National Natural Science Foundation of China(22378181).
文摘The development of materials with excellent microwave absorption(MWA)and electromagnetic interference(EMI)shielding performances has currently received attention.Herein,mesophase pitch-based carbon foam(MPCF)with 3D interconnected pore structure was prepared through the high pressure pyrolysis of mesophase coal tar pitch.It is found that the 3D interconnected cellular pores of MPCF facilitate multiple reflections of electromagnetic waves,which results in the minimum reflection loss(RLmin)value of MPCF reaches-37.84 dB with the effective absorption bandwidth(EAB)of 5.44 GHz at a thickness of 2.70 mm,and the total average electromagnetic shielding effectiveness(SE_(T))under 3.00 mm thickness achieves 26.52 dB in X-band.Subsequently,MPCF is activated by KOH to obtain activated carbon foam(A-MPCF).The average SE_(T)of A-MPCF achieves 103.00 dB for abundant nanopores on the pore cell walls,which leads to a transition from the multiple reflections of electromagnetic waves on the walls to diffuse reflection.Unfortunately,the reflection coefficient(R)of A-MPCF increases from 0.78 to 0.90.To reduce the R value,Fe_(3)O_(4)/A-MPCF was fabricated via the in situ growth of nano Fe_(3)O_(4)on A-MPCF.Consequently,the R value of Fe_(3)O_(4)/A-MPCF was reduced from 0.90 to 0.74,whereas the MWA performance was only slightly decreased.This work proposes a simple strategy for simultaneously adjusting MWA and EMI shielding performances of materials.
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.
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.
文摘Environmental pollution,energy consumption,and greenhouse gas emissions are critical global issues.To address these challenges,optimizing skimmer coatings is a major step in commercializing cleaning oil stains.This research presents a novel approach to creating and refining oil absorbent coatings,introducing a unique oil spill removal skimmer enhanced with a super hydrophobic polyaniline(PANI)nanofiber coating.The goal of this study was to improve oil absorption performance,increase the contact angle,lower drag,reduce energy consumption,achieve high desirability,and lower production costs.PANI treated with hydrochloric acid was a key focus as it resulted in higher porosity and smaller pore diameters,providing a larger surface area,which are crucial factors for boosting oil absorption and minimizing drag.To optimize optimal nanofiber morphology,PANI synthesized with methanesulfonic acid was first dedoped and then redoped with hydrochloric acid.After optimization,the most effective skimmer coating was achieved using a formulation consisting of 0.1%PANI,an ammonium persulfate/aniline ratio of 0.4,and an acid/aniline ratio of 9.689,along with redoped PANI nanofibers.The optimized skimmer exhibited a remarkable contact angle of 177.477°.The coating achieved drag reduction of 32%,oil absorption of 88.725%,a cost of$1.710,and a desirability rating of 78.5%.In this study,an optimized skimmer coat containing super hydrophobic coat-PANI nanofibers was fabricated.By enhancing contact angle and reducing drag,these coatings increased the skimmer performance by improving oil absorption and reducing fuel consumption.
基金supported by the National Natural Science Foundation of China(52562043)Jiangxi Provincial Natural Science Foundation(20244BAB28050)。
文摘The rapid advancement of 5G/6G communication and radar technology has exacerbated issues of electromagnetic wave(EMW)leakage,interference,and thermal management.Therefore,developing lightweight EMW absorbers that integrate strong absorption,broad bandwidth,and thermal stability is crucial.Herein,a 3D MXene sponge/NiFe@NC heterostructure with tunable pore architecture is constructed by pyrolyzing a polyurethane(PU)foam template uniformly coated with NiFe-decorated Ti_(3)C_(2)T_(x)MXene nanosheets.The resulting porous dielectric-magnetic network integrates interconnected MXene pathways with uniformly dispersed NiFe@NC nanoparticles,enabling a synergistic effect of dielectric-magnetic loss through conduction loss,dipole/interface polarization,and magnetic loss.Precise pore structure design enhances impedance matching and promotes multi-scattering and internal reflection of EMWs.Notably,an“EMW-pore matching”mechanism is proposed,whereby pore size governs the impedance matching at specific frequencies,enabling tunable absorption performance.The optimized absorber achieves a reflection loss(RL)of-67.84 dB,while radar cross-section(RCS)simulations confirm its exceptional attenuation and stealth potential.Additionally,the 3D skeleton derived from PU foam confers remarkable thermal resistance and flame retardancy.This pore-regulation strategy provides a scalable route to designing lightweight,broadband,and thermally stable EMW absorbers for next-generation communication and stealth applications.
基金the National Key R&D Program of China(No.2024YFE0110001)the National Natural Science Foundation of China(U1932219)the Mobility Programme endorsed by the Joint Committee of the Sino-German Center(M0728)。
文摘The ultracold neutron(UCN)transport code,MCUCN,designed initially for simulating UCN transportation from a solid deuterium(SD_2)source and neutron electric dipole moment experiments,could not simulate UCN storage and transportation in a superfluid^(4)He(SFHe,He-Ⅱ)source accurately.This limitation arose from the absence of an^(4)He upscattering mechanism and the absorption of^(3)He.And the provided source energy distribution in MCUCN is different from that in SFHe source.This study introduced enhancements to MCUCN to address these constraints,explicitly incorporating the^(4)He upscattering effect,the absorption of^(3)He,the loss caused by impurities on converter wall,UCN source energy distribution in SFHe,and the transmission through negative optical potential.Additionally,a Python-based visualization code for intermediate states and results was developed.To validate these enhancements,we systematically compared the simulation results of the Lujan Center Mark3 UCN system by MCUCN and the improved MCUCN code(iMCUCN)with UCNtransport simulations.Additionally,we compared the results of the SUN1 system simulated by MCUCN and iMCUCN with measurement results.The study demonstrates that iMCUCN effectively simulates the storage and transportation of ultracold neutrons in He-Ⅱ.
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 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funded by Shenzhen Science and Technology Program,grant number No.ZDSYS20230626091400001No.KCXST20221021111609024No.KCXFZ20240903093459001.
文摘This study addresses the energy-intensive challenge of small-scale biogas upgrading by optimizing a chemical absorption process employing methyl diethanolamine(MDEA).Focusing on a typical distributed application of 300 Nm^(3)/d,we developed an integrated simulation-optimization framework using Aspen HYSYS 14.0 to systematically evaluate the effects of critical operating parameters—absorption pressure,MDEA concentration,flow rate,temperature,number of trays,and reboiler duty—on methane purity and energy consumption.The key finding is the identification of an optimal parameter set:absorption pressure of 1200 kPa,MDEA concentration of 20mol%,lean flow rate of 2.5 kmol/h,temperature of 298.15 K,20 absorber trays,10 regenerator trays,and a reboiler duty of 4 kW,which enabled the product gas to achieve a high CH4 concentration of 97mol%,compliant with pipeline standards.A detailed energy consumption analysis revealed that the reboiler is the most energy-intensive unit,accounting for 75.40%of the total 5.29 kW energy consumption,followed by the gas compressor(23.38%).The specific energy consumption for CH4 recovery and the Energy Consumption Index(ECI)were quantified at 0.8852 kWh/kg CH_(4)and 6.82,respectively.This work provides a validated optimization strategy and critical energy breakdown,offering practical guidance for enhancing the technical and economic viability of small-scale,centralized biogas purification systems.
基金supported by the National Natural Science Foundation of China(Grants Nos.12304405,12275203,and 12075176)the Natural Science Foundation of Shaanxi Provincial Department of Education(Grant No.23JK0483)+2 种基金the Natural Science Basic Research Program of Shaanxi(Grant Nos.2024JC-YBMS-521 and 2024JC-YBMS-039)the 2022 Shaanxi University Youth Innovation Team Project(Grant No.K20220186)the College Students’Innovative Entrepreneurial Training Plan Program of Shaanxi(Grant No.S202410702178)。
文摘Coherent perfect absorption(CPA)and coherent perfect transmission(CPT)are two extreme states arising from the manipulation of optical fields.Generally,CPA and CPT occur under different input-field phases.Therefore,we propose a scheme to realize an all-optical switch based on phase-dependent CPA–CPT conversion.In our proposal,the CPT state and the CPA state are treated as the on state and the off state,respectively.Consequently,the efficiency of this all-optical switch can reach the maximum value of 1.With the introduction of an incoherent pump field,the CPA state can be achieved under a weaker input probe field or can be converted into a CPT state.The results show that the optical switch can operate with weaker fields and can be further optimized by the application of an incoherent field.
基金supported by the National Natural Science Foundation of China(No.12472136)Innovation Fund of Marine Defense Technology Innovation Center(No.25GFC-JJ16-3608).
文摘Negative Poisson’s ratio materials and structures exhibit lateral expansion under tensile loading,demonstrating significant mechanical advantages over conventional materials.This study systematically investigated three typical two-dimensional negative Poisson’s ratio metamaterial structures(Concave honeycomb,Anti-chiral,and Anti-chiral concave honeycomb hybrid structures)through both experimental tests and numerical analysis.The test specimens were fabricated using selective laser melting(SLM)additive manufacturing technology,and the experimental test was conducted with the use of a DIC strain measurement system.The numerical studies were performed considering both static tensile loading and dynamic impact loading with different strain rates.The deformation behaviors,failure process,negative Poisson’s ratio effects,and energy absorption capacity of the three different metamaterial structures are systematically investigated,and the associated mechanical mechanisms are thoroughly revealed.Results and findings of this work could provide valuable guidance for the engineering design and application of negative Poisson’s ratio metamaterials and structures.
