FeAl/TiC composites were fabricated by hot pressing blended elemental powders. The effects of Ni-doping on thedensification and mechanical properties of the composites were studied. Results show that the density of th...FeAl/TiC composites were fabricated by hot pressing blended elemental powders. The effects of Ni-doping on thedensification and mechanical properties of the composites were studied. Results show that the density of the composites decreases with the content of TiC increasing, and the addition of Ni significantly improves the densificationprocess by enhancing mass transfer in the bonding phase. The mechanical properties of the composites are closelyrelated with their porosity. Besides increasing the density of the composites, the addition of Ni improves the mechanical properties by other three effects: solution-strengthening the bonding phase, strengthening the FeAI-TiC interfaceand increasing ductile fracture in FeAl phase.展开更多
Food-derived polysaccharides are gaining popularity across diverse food applications due to their wideranging bioactivities and distinctive properties.The specific targeting of glycoside hydrolases towards glycosidic ...Food-derived polysaccharides are gaining popularity across diverse food applications due to their wideranging bioactivities and distinctive properties.The specific targeting of glycoside hydrolases towards glycosidic bonds lays the groundwork for synthesizing and exploring specific structural segments of polysaccharides,offering crucial implications in the food industry.However,macromolecular polysaccharides demonstrate limited biological activities as their active centers are tightly enveloped,posing challenges for traversing cell membrane barriers.By selectively cleaving partial glycosidic linkages in polysaccharides,glycoside hydrolases decrease the polymerization of polysaccharide molecules and effectively change the structural characteristics,where a series of smaller polysaccharide fragments can be generated for improving the bioactivities and properties in some respects.This review examines the role of glycoside hydrolases in degrading food-derived polysaccharides,the structure-function relationships,reaction conditions,and the current application status of degraded polysaccharides is discussed in particular.In addition,we also highlight challenges and future directions worth attention in the application of enzymes and polysaccharides.Overall,the present review will provide an efficient method for producing bioactivity-enhanced polysaccharides,which can improve the effectiveness and safety of functional foods to safeguard human wellness.展开更多
Fatigue fracture is the major threat to the railway axle, which can be avoided or delayed by surface strengthening. In this study, a low-carbon alloy axle steel with two states was treated by surface induction hardeni...Fatigue fracture is the major threat to the railway axle, which can be avoided or delayed by surface strengthening. In this study, a low-carbon alloy axle steel with two states was treated by surface induction hardening and shot peening, respectively, to reveal the mechanism of fatigue property improvement by microstructure characterization, microhardness measurement, residual stress analysis, roughness measurement, and rotary bending fatigue tests. The results indicate that both quenching and tempering treatment can effectively improve the fatigue properties of the modified axle steel. In addition, induction hardening can create an ideal hardened layer on the sample surface by phase transformation from the microstructure of ferrite and pearlite to martensite. By comparison, shot peening can modify the microstructure in surface layer by surface severe plastic deformation introducing a large number of dislocation and even cause grain refinement. Both induction hardening and shot peening create compressive residual stress into the surface layer of axle steel sample, which can effectively reduce the stress level applied to the metal surface during the rotary bending fatigue tests. On the whole, the contribution of induction hardening to the fatigue life of axle steel sample is better than that of the shot peening, and induction hardening shows obvious advantages in improving the fatigue life of axle steel.展开更多
The use of a natural white juice, taken from magrabe banana stem, as concrete admixture to improve mechanical and physicrvchemical properties of concrete has been studied. The compressive strength, bulk density the fr...The use of a natural white juice, taken from magrabe banana stem, as concrete admixture to improve mechanical and physicrvchemical properties of concrete has been studied. The compressive strength, bulk density the free lime liberated during hydration and the combined water content were determined. The results indicate that the admixture acts as a retarder in most cases and as accelerator in some ones. Also, the admixture effect on the corrosion resistance of the reinforcing steel against surrounding aggressive media has been investigated using galvanostatic polarization technique. The addition of 0.2% admixture leads to the more inhibition of the steel展开更多
We report an effective method to improve the formation of nickel stanogermanide（Ni Ge Sn） by the incorporation of a platinum（Pt） interlayer. After the Ni/Pt/Ge Sn samples are annealed we obtain uniform Ni Ge Sn th...We report an effective method to improve the formation of nickel stanogermanide（Ni Ge Sn） by the incorporation of a platinum（Pt） interlayer. After the Ni/Pt/Ge Sn samples are annealed we obtain uniform Ni Ge Sn thin films,which are characterized by means of sheet resistance, atomic force microscopy, scanning electron microscopy,cross-section transmission electron microscopy, and energy dispersive x-ray spectroscopy. These results show that the presence of Pt increases the smoothness and uniform morphology of Ni Ge Sn films.展开更多
Introducing B2 ordering can effectively improve the mechanical properties of lightweight refractory high-entropy alloys(LRHEAs).However,(Zr,Al)-enriched B2 precipitates generally reduce the ductility because their ord...Introducing B2 ordering can effectively improve the mechanical properties of lightweight refractory high-entropy alloys(LRHEAs).However,(Zr,Al)-enriched B2 precipitates generally reduce the ductility because their ordering characteristic is destroyed after dislocation shearing.Meanwhile,the local chemical order(LCO)cannot provide an adequate strengthening effect due to its small size.展开更多
1.Introduction The strength of metallic materials can be ameliorated by introducing boundaries,precipitates,or defects as obstacles to dislocation movement[1].However,high strength is generally obtained at the sacrifi...1.Introduction The strength of metallic materials can be ameliorated by introducing boundaries,precipitates,or defects as obstacles to dislocation movement[1].However,high strength is generally obtained at the sacrifice of plastic deformation capability[2].Lately,many strategies have been proposed to improve the comprehensive properties of materials,among which manipulating stacking fault energy(SFE)is effective[3–5].展开更多
This study investigated the potential of locally sourced mushrooms as a sustainable alternative to marine-derived chitosan in papermaking.Chitosan was extracted from four local(Boletus edulis,Suillus luteus,Leccinum a...This study investigated the potential of locally sourced mushrooms as a sustainable alternative to marine-derived chitosan in papermaking.Chitosan was extracted from four local(Boletus edulis,Suillus luteus,Leccinum auran-tiacum,Suillus variegatus),one commercially available(Agaricus bisporus)and one laboratory-grown(Phanero-chaete chrysosporium)fungal species.Paper handsheets were prepared using either 100%regenerated paper or a 50/50 blend of regenerated paper and hemp fibres.2.5%chitosan(based on dry mass)was incorporated into the paper mass,using chitosan sourced from B.edulis,A.bisporus,P.chrysosporium,and crustacean chitosan.Fungal chitosan sources were selected based on multiple factors.B.edulis exhibited the highest chitosan yield(5.03%),the highest degree of deacetylation(77.0%)and the highest molecular weight(59.18 kDa).It is also a widely prevalent species in the Baltic region.A.bisporus demonstrated the highest degree of crystallinity(62.7%).Additionally,it has readily available waste material due to its popularity in the food industry.P.chysosporium,with its low degree of crystallinity(33.9%)and small molecular weight(9.06 kDa),is easily cultivable in laboratory conditions.Mechanical testing of papers showed that fungal chitosan significantly improved tensile index and elongation at break(in wet and dry states)and burst strength while reducing air permeability.Notably,fungal chitosan con-sistently outperformed crustacean chitosan.Commercially available A.bisporus and locally sourced B.edulis emerged as promising alternatives to crustacean chitosan in papermaking.Further research is needed to explore other applications for fungal chitosan.展开更多
Compared to traditional superhard materials with high electron density and short,strong covalent bonds,alloy materials mainly composed of metallic bonding structures typically have great toughness and lower hardness.B...Compared to traditional superhard materials with high electron density and short,strong covalent bonds,alloy materials mainly composed of metallic bonding structures typically have great toughness and lower hardness.Breaking through the limits of alloy materials is a preface and long-term topic,which is of great significance and value for improving the comprehensive mechanical properties of alloy materials.Here,we report on the discovery of a cubic alloy semiconducting material Ti_(2)Co with a large Vickers of hardness K_(v)^(exp)∼6.7GPa and low fracture toughness of K_(IC)^(exp)∼1.51MPa·m^(1/2).Unexpectedly,the K_(v)^(exp)∼6.7GPa is nearly triple of the K_(v)^(cal)∼2.66GPa predicted by density functional theory(DFT)calculations and theK_(IC)^(exp)∼1.51MPa·m^(1/2)is about one or two orders of magnitude smaller than that of ordinary titanium alloy materials(K_(IC)^(exp)∼30-120MPa·m^(1/2)).These specifications place Ti_(2)Co far from the phase space of the known alloy materials.Upon incorporation of oxygen into structural void positions,both values were simultaneously improved for Ti_(4)Co_(2)O to∼9.7GPa and∼2.19MPa·m^(1/2),respectively.Further DFT calculations on the electron localization function of Ti_(4)Co_(2)X(X=B,C,N,O)vs.the interstitial elements indicate that these simultaneous improvements originate from the coexistence of Ti-Co metallic bonds,the emergence of newly oriented Ti-X covalent bonds,and the increase of electron concentration.Moreover,the large difference between K_(v)^(exp)and K_(v)^(cal)of Ti_(2)Co suggests underlying mechanism concerning the absence of the O(16d)or Ti_(2)-O bonds in the O-(Ti_(2))_(6) octahedron.This discovery proposes a new pathway to simultaneously improve the comprehensive mechanical performances and illuminates the path of exploring superconducting materials with excellent mechanical performances.展开更多
Previous results revealed that the defect and/or interface had a great impact on the electromagnetic pa-rameters of materials.In order to understand the main physical mechanisms and effectively utilize these strategie...Previous results revealed that the defect and/or interface had a great impact on the electromagnetic pa-rameters of materials.In order to understand the main physical mechanisms and effectively utilize these strategies,in this study,M Fe_(2)O_(4)and flower-like core@shell M Fe_(2)O_(4)@MoS_(2)(M=Mn,Ni,and Zn)sam-ples with different categories were elaborately designed and selectively produced in large scale through a simple two-step hydrothermal reaction.We conducted the systematical investigation on their microstruc-tures,electromagnetic parameters and microwave absorption performances(MAPs).The obtained results revealed that the large radius of M^(2+)cation could effectively boost the concentration of oxygen vacancy in the M Fe_(2)O_(4)and M Fe_(2)O_(4)@MoS_(2)samples,which resulted in the improvement of dielectric loss capabil-ities and MAPs.Furthermore,the introduction of MoS_(2)nanosheets greatly improved the interfacial effect and enhanced the polarization loss capabilities,which also boosted the MAPs.By taking full advantage of the defect and interface,the designed M Fe_(2)O_(4)@MoS_(2)samples displayed tunable and excellent com-prehensive MAPs including strong absorption capability,wide absorption bandwidth and thin matching thicknesses.Therefore,the clear understanding of defect and interface engineering made these strategies well elaborately designed and applicable to improving MAPs.展开更多
ZnO/graphene oxide（ZnO/GO） composite material,in which ZnO nanoparticles were densely coated on the GO nanosheets,was successfully prepared by an improved two-step method and characterized by IR, XRD,TEM,and UV-vis ...ZnO/graphene oxide（ZnO/GO） composite material,in which ZnO nanoparticles were densely coated on the GO nanosheets,was successfully prepared by an improved two-step method and characterized by IR, XRD,TEM,and UV-vis techniques.The improved photocatalytic property of the ZnO/GO composite material,evaluated by the photocatalytic degradation of methyl orange（MO） under UV irradiation,is ascribed to the intimate contact between ZnO and GO,the enhanced adsorption of MO,the quick electron transfer from excited ZnO particles to GO sheets and the activation of MO molecules viaπ-πinteraction between MO and GO.展开更多
Continuous CNT fibers have been directly fabricated in a speed of 50 m/h-400 m/h,based on an improved chemical vapor deposition method.As-prepared fibers are further post-treated by acid.According to the SEM images an...Continuous CNT fibers have been directly fabricated in a speed of 50 m/h-400 m/h,based on an improved chemical vapor deposition method.As-prepared fibers are further post-treated by acid.According to the SEM images and Raman spectra,the acid treatment results in the compaction and surface modification of the CNTs in fibers,which are beneficial for the electron and load transfer.Compared to the HNO3 treatment,HClSO_3 or H_2SO_4 treatment is more effective for the improvement of the fibers＇ properties.After HCISO_3 treatment for 2 h,the fibers＇ strength and electrical conductivity reach up to-2 GPa and-4.3 MS/m,which are promoted by-200%and almost one order of magnitude than those without acid treatment,respectively.The load-bearing status of the CNT fibers are analyzed based on the downshifts of the G＇ band and the strain transfer factor of the fibers under tension.The results reveal that acid treatment could greatly enhance the load transfer and inter-bundle strength.With the HCISO3 treatment,the strain transfer factor is enhanced from-3.9%to-53.6%.展开更多
Microbial-induced carbonate precipitation(MICP)has emerged as a promising eco-friendly and cost-effective alternative for improving the strength and stability of low-cohesion soils.This review provides an in-depth ana...Microbial-induced carbonate precipitation(MICP)has emerged as a promising eco-friendly and cost-effective alternative for improving the strength and stability of low-cohesion soils.This review provides an in-depth analysis of the microscopic mechanisms,implementation methods,and macroscopic properties of MICP in soil enhancement.The biogeochemical processes underlying MICP,including urea hydrolysis,denitrification,sulfate reduction,photosynthesis,and iron reduction,are discussed in detail.Various MICP implementation methods,such as two-phase treatment,one-phase treatment,and ex-situ mixing,are reviewed,highlighting their respective advantages and limitations in reinforcing low-cohesion soils.The review also addresses the performance of MICP-treated soils,including improvements in strength,stiffness,permeability,and durability.Furthermore,the key challenges and future prospects for microbial soil reinforcement technologies are summarized.Future research should focus on optimizing nutrient supply,enhancing bacterial retention and activity,controlling the crystallization process,conducting pilot projects,and reducing treatment costs.These efforts are crucial for advancing the practical application of MICP in sustainable infrastructure construction.This review aims to advance the understanding of MICP and its potential for sustainable soil improvement,offering valuable insights for geotechnical engineers.展开更多
We report a simple and effective method to realize desirable interfacial property for inverted planar perovskite solar cells(PSCs)by using small molecule ethanediamine for the construction of a novel polyelectrolyte h...We report a simple and effective method to realize desirable interfacial property for inverted planar perovskite solar cells(PSCs)by using small molecule ethanediamine for the construction of a novel polyelectrolyte hole transport material(P3CT-ED HTM).It is found that P3CT-ED can not only improve the hole transport property of P3CT-K but also improve the crystallinity of adjacent perovskite film.In addition,the introduction of ethanediamine into P3CT realigns the conduction and valence bands upwards,passivates surface defects and reduces nonradiative recombination.As a consequence,compared to P3CT-K hole transport layer(HTL)based devices,the average power conversion efficiency(PCE)is boosted from17.2% to 19.6% for the counterparts with P3CT-ED,with simultaneous enhancement in open circuit voltage and fill factor.The resultant device displays a champion PCE of 20.5% with negligible hysteresis.展开更多
The reduction of the hygroscopicity of wood fibers was investigated through a Thermal Treatment(TT)on wood chips performed before the defibering process.The TT and defibering tests were both carried out on a continuou...The reduction of the hygroscopicity of wood fibers was investigated through a Thermal Treatment(TT)on wood chips performed before the defibering process.The TT and defibering tests were both carried out on a continuous pilot at semi-industrial scale.The thermal treatment study of wood chips,equivalent to a low temperature pyrolysis,was achieved for four conditions(280°C–320°C)for a duration of 10 min.Mass quantification of solids,condensables and gases(FTIR)at the outcome of the thermal treatment allowed to achieve the mass balances for each condition.The increase of the reactor temperature from 280°C to 320°C leads to a lower solid yield(94%–82%)while gaseous(1%–3.8%)and condensable(3%–11%)products increase significantly.Thermally treated wood samples were afterwards successfully defibered in different conditions to produce suitable fibers for insulation panel production.The aim of the study is also to evaluate the effects of the TT on the lowering of energy consumption necessary for the defibering process while producing good quality fibers.Energy consumption during defibering process shows a significant decrease with the increase the TT severity.Fiber morphology is affected by TT and the morphological quality of the fibers decreases as TT severity increases.The mass percentage of dust was also quantified as a quality marker of produced fibers.Measurements of equilibrium moisture(at 20°C and 65%RH)of the different materials(wood chips before and after TT,produced fibers)show a significant effect of the TT on wood chips hygroscopicity(8.2%for untreated wood to 4.1%for TT at 320°C).However,the effect of the TT on the hygroscopicity reduction of thermally treated wood fibers is drastically less significant due to breaking of the wood structure during defibering process.展开更多
Fracturing fluid property play a critical role in developing unconventional reservoirs.Deep eutectic solvents(DESs)show fascinating potential for property improvement of clean fracturing fluids(CFFs)due to their low-p...Fracturing fluid property play a critical role in developing unconventional reservoirs.Deep eutectic solvents(DESs)show fascinating potential for property improvement of clean fracturing fluids(CFFs)due to their low-price,low-toxicity,chemical stability and flexible designability.In this work,DESs were synthesized by mixing hydrogen bond acceptors(HBAs)and a given hydrogen bond donor(HBD)to explore their underlying influence on CFF properties based on the intermolecular interactions.The hydrogen-bonding,van der Waals and electrostatic interactions between DES components and surfactants improved the CFF properties by promoting the arrangement of surfactants at interface and enhancing the micelle network strength.The HBD enhanced the resistance of CFF for Ca^(2+) due to coordination-bonding interaction.The DESs composed of choline chloride(ChCl)and malonic acid show great enhancement for surface,rheology,temperature resistance,salt tolerance,drag reduction,and gel-breaking performance of CFFs.The DESs also improved the gel-breaking CFF-oil interactions,increasing the imbibition efficiencies to 44.2%in 74 h.Adjusting HBAs can effectively strengthen the intermolecular interactions(e.g.,HBA-surfactant and HBD-surfactant interactions)to improve CFF properties.The DESs developed in this study provide a novel strategy to intensify CFF properties.展开更多
This study investigates the use of struviterient-loaded magnesium-modified biochar beads(Ca/MgBC+NP)as a slow-release fertilizer and soil amendment,comparing its performance with commercially available slow-release fe...This study investigates the use of struviterient-loaded magnesium-modified biochar beads(Ca/MgBC+NP)as a slow-release fertilizer and soil amendment,comparing its performance with commercially available slow-release fertilizers(SRF)in different soils and crop types.The results demonstrate that Ca/MgBC+NP exhibited satisfying swelling,water retention,and slow-release properties in all tested soils.In sandy soil,which showed the most significant differences(p<0.05),Ca/MgBC+NP enhanced the growth of Brassica chinensis L.and Spinacia oleracea L.after 90 d,with shoot and root lengths,as well as fresh and dry weights,1.25-2.84 times higher than those treated with SRF.The cation exchange capacity and organic carbon content of sandy soil were significantly improved(by 38.55%and 265.38%),overcoming its natural limitations in water and fertilizer retention.Principal Component Analysis(PCA)confirmed that soil properties played a crucial role in crop growth(52.67%variance explained).Spectroscopic analysis indicated that magnesium-related compounds,including struvite and Mg(PO_(4))_(3),contributed to the observed growth promotion.Furthermore,Ca/MgBC+NP effectively immobilized heavy metals,particularly Cr and Hg,with immobilization rates exceeding 80%.This study highlights the potential of Ca/MgBC+NP as a sustainable,low-cost fertilizer that not only enhances crop growth but also improves soil health and remediates heavy metal contamination,providing a promising alternative for green agriculture.展开更多
The power conversion efficiency(PCE)and stability of organic-inorganic hybrid perovskite solar cells(PSCs)are limited by the energy level mismatches and substantial defects.Interface engineering is a reliable strategy...The power conversion efficiency(PCE)and stability of organic-inorganic hybrid perovskite solar cells(PSCs)are limited by the energy level mismatches and substantial defects.Interface engineering is a reliable strategy for solving these problems.Here,we synthesized three small dipole molecules,named PzT-TPA,PzTA-TPA,and PzTA-TPAS,which were introduced into the interface between the perovskite and the hole-transport layers.The advantages of the interface dipole material included regulating the energy band structure,enhancing the built-in electric field and promoting the carrier transport.Compared with the pristine device,the PzTA-TPAS-treated device showed significantly improved photoelectric properties,including an optimal PCE of 25.55%,an impressive open-circuit voltage(V_(OC))of 1.177 V and an excellent operational stability.展开更多
Defect and interface engineering are efficient approaches to adjust the physical and chemical properties of nanomaterials.In order to effectively utilize these strategies for the improvement of microwave absorption pr...Defect and interface engineering are efficient approaches to adjust the physical and chemical properties of nanomaterials.In order to effectively utilize these strategies for the improvement of microwave absorption properties(MAPs),in this study,we reported the synthesis of hollow carbon shells and hollow carbon@MoS_(2)nanocomposites by the template-etching and templateetching-hydrothermal methods,respectively.The obtained results indicated that the degree of defect for hollow carbon shells and hollow carbon@MoS_(2)could be modulated by the thickness of hollow carbon shell,which effectively fulfilled the optimization of electromagnetic parameters and improvement of MAPs.Furthermore,the microstructure investigations revealed that the precursor of hollow carbon shells was encapsulated by the sheet-like MoS_(2)in high efficiency.And the introduction of MoS_(2)nanosheets acting as the shell effectively improved the interfacial effects and boosted the polarization loss capabilities,which resulted in the improvement of comprehensive MAPs.The elaborately designed hollow carbon@MoS_(2)samples displayed very outstanding MAPs including strong absorption capabilities,broad absorption bandwidth,and thin matching thicknesses.Therefore,this work provided a viable strategy to improve the MAPs of microwave absorbers by taking full advantage of their defect and interface engineering.展开更多
基金This work was supported by Hunan Provincial Natural Science Foundation.
文摘FeAl/TiC composites were fabricated by hot pressing blended elemental powders. The effects of Ni-doping on thedensification and mechanical properties of the composites were studied. Results show that the density of the composites decreases with the content of TiC increasing, and the addition of Ni significantly improves the densificationprocess by enhancing mass transfer in the bonding phase. The mechanical properties of the composites are closelyrelated with their porosity. Besides increasing the density of the composites, the addition of Ni improves the mechanical properties by other three effects: solution-strengthening the bonding phase, strengthening the FeAI-TiC interfaceand increasing ductile fracture in FeAl phase.
基金supported by the Jiangsu Province University Basic Science(Natural Science)Research Major Project(24KJA360007)Nanjing University of Chinese Medicine TCM First-Class Discipline"Leading Plan"Scientific Research Project(ZYXYL2024-001)+3 种基金Jiangsu Provincial TCM Science and Technology Development Program Project(MS2021004)High Level Key Discipline Construction Project of the National Administration of Traditional Chinese Medicine-Resource Chemistry of Chinese Medicinal Materials(ZYYZDXK-2023083)National Administration of Traditional Chinese Medicine Chinese Medicine Innovation Team and Talent Support Program Project(ZYYCXTD-D-202005)2022 Student Innovation Training Program Project(103152022075).
文摘Food-derived polysaccharides are gaining popularity across diverse food applications due to their wideranging bioactivities and distinctive properties.The specific targeting of glycoside hydrolases towards glycosidic bonds lays the groundwork for synthesizing and exploring specific structural segments of polysaccharides,offering crucial implications in the food industry.However,macromolecular polysaccharides demonstrate limited biological activities as their active centers are tightly enveloped,posing challenges for traversing cell membrane barriers.By selectively cleaving partial glycosidic linkages in polysaccharides,glycoside hydrolases decrease the polymerization of polysaccharide molecules and effectively change the structural characteristics,where a series of smaller polysaccharide fragments can be generated for improving the bioactivities and properties in some respects.This review examines the role of glycoside hydrolases in degrading food-derived polysaccharides,the structure-function relationships,reaction conditions,and the current application status of degraded polysaccharides is discussed in particular.In addition,we also highlight challenges and future directions worth attention in the application of enzymes and polysaccharides.Overall,the present review will provide an efficient method for producing bioactivity-enhanced polysaccharides,which can improve the effectiveness and safety of functional foods to safeguard human wellness.
基金financially supported by the National Key Research and Development Project(No.2017YFB0703004)the National Natural Science Foundation of China(NSFC,No.U1664253)the LiaoNing Revitalization Talents Program(No.XLYC1808027)。
文摘Fatigue fracture is the major threat to the railway axle, which can be avoided or delayed by surface strengthening. In this study, a low-carbon alloy axle steel with two states was treated by surface induction hardening and shot peening, respectively, to reveal the mechanism of fatigue property improvement by microstructure characterization, microhardness measurement, residual stress analysis, roughness measurement, and rotary bending fatigue tests. The results indicate that both quenching and tempering treatment can effectively improve the fatigue properties of the modified axle steel. In addition, induction hardening can create an ideal hardened layer on the sample surface by phase transformation from the microstructure of ferrite and pearlite to martensite. By comparison, shot peening can modify the microstructure in surface layer by surface severe plastic deformation introducing a large number of dislocation and even cause grain refinement. Both induction hardening and shot peening create compressive residual stress into the surface layer of axle steel sample, which can effectively reduce the stress level applied to the metal surface during the rotary bending fatigue tests. On the whole, the contribution of induction hardening to the fatigue life of axle steel sample is better than that of the shot peening, and induction hardening shows obvious advantages in improving the fatigue life of axle steel.
文摘The use of a natural white juice, taken from magrabe banana stem, as concrete admixture to improve mechanical and physicrvchemical properties of concrete has been studied. The compressive strength, bulk density the free lime liberated during hydration and the combined water content were determined. The results indicate that the admixture acts as a retarder in most cases and as accelerator in some ones. Also, the admixture effect on the corrosion resistance of the reinforcing steel against surrounding aggressive media has been investigated using galvanostatic polarization technique. The addition of 0.2% admixture leads to the more inhibition of the steel
基金Supported by the National Natural Science Foundation of China under Grant Nos 51672171 and 61604094the Natural Science Foundation of Shanghai under Grant No 14ZR1418300+2 种基金the National Key Basic Research Program of China under Grant No 2015CB921600the Eastern Scholar Program from the Shanghai Municipal Education Commissionthe Fok Ying Tung Education Foundation
文摘We report an effective method to improve the formation of nickel stanogermanide（Ni Ge Sn） by the incorporation of a platinum（Pt） interlayer. After the Ni/Pt/Ge Sn samples are annealed we obtain uniform Ni Ge Sn thin films,which are characterized by means of sheet resistance, atomic force microscopy, scanning electron microscopy,cross-section transmission electron microscopy, and energy dispersive x-ray spectroscopy. These results show that the presence of Pt increases the smoothness and uniform morphology of Ni Ge Sn films.
基金supported by the National Natural Science Foundation of China(Nos.52171166 and U20A20231)the Natural Science Foundation of Hunan Province,China(Nos.2024JJ2060 and 2024JJ5406)+1 种基金the Key Laboratory of Materials in Dynamic Extremes of Sichuan Province(No.2023SCKT1102)the Postgraduate Scientific Research Innovation Project of National University of Defense Technology(No.XJJC2024065).
文摘Introducing B2 ordering can effectively improve the mechanical properties of lightweight refractory high-entropy alloys(LRHEAs).However,(Zr,Al)-enriched B2 precipitates generally reduce the ductility because their ordering characteristic is destroyed after dislocation shearing.Meanwhile,the local chemical order(LCO)cannot provide an adequate strengthening effect due to its small size.
基金financially supported by the National Natural Science Foundation of China(NSFC)under grant No.52371100.
文摘1.Introduction The strength of metallic materials can be ameliorated by introducing boundaries,precipitates,or defects as obstacles to dislocation movement[1].However,high strength is generally obtained at the sacrifice of plastic deformation capability[2].Lately,many strategies have been proposed to improve the comprehensive properties of materials,among which manipulating stacking fault energy(SFE)is effective[3–5].
基金funded by the Latvian Council of Science Project No.lzp-2023/1-0123“Development of Biopolymer-Based Hydrophobic Multi-Layer Packaging Material from Biomass Waste Streams”。
文摘This study investigated the potential of locally sourced mushrooms as a sustainable alternative to marine-derived chitosan in papermaking.Chitosan was extracted from four local(Boletus edulis,Suillus luteus,Leccinum auran-tiacum,Suillus variegatus),one commercially available(Agaricus bisporus)and one laboratory-grown(Phanero-chaete chrysosporium)fungal species.Paper handsheets were prepared using either 100%regenerated paper or a 50/50 blend of regenerated paper and hemp fibres.2.5%chitosan(based on dry mass)was incorporated into the paper mass,using chitosan sourced from B.edulis,A.bisporus,P.chrysosporium,and crustacean chitosan.Fungal chitosan sources were selected based on multiple factors.B.edulis exhibited the highest chitosan yield(5.03%),the highest degree of deacetylation(77.0%)and the highest molecular weight(59.18 kDa).It is also a widely prevalent species in the Baltic region.A.bisporus demonstrated the highest degree of crystallinity(62.7%).Additionally,it has readily available waste material due to its popularity in the food industry.P.chysosporium,with its low degree of crystallinity(33.9%)and small molecular weight(9.06 kDa),is easily cultivable in laboratory conditions.Mechanical testing of papers showed that fungal chitosan significantly improved tensile index and elongation at break(in wet and dry states)and burst strength while reducing air permeability.Notably,fungal chitosan con-sistently outperformed crustacean chitosan.Commercially available A.bisporus and locally sourced B.edulis emerged as promising alternatives to crustacean chitosan in papermaking.Further research is needed to explore other applications for fungal chitosan.
基金supported by the National Key Research and Development Program of China(Grant Nos.2024YFA1408400,2023YFA1406100,2023YFA1607400,2022YFA1403800,and 2022YFA1403203)the National Natural Science Foundation of China(Grant Nos.12474055,12404067,12025408,52025026,and U23A6003)+3 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB33000000)the Chinese Academy of Sciences President’s International Fellowship Initiative(Grant No.2024PG0003)the Outstanding Member of Youth Promotion Association of Chinese Academy of Sciences(Grant No.Y2022004)supported by the CAC station of Synergetic Extreme Condition User Facility(SECUF,https://cstr.cn/31123.02.SECUF)。
文摘Compared to traditional superhard materials with high electron density and short,strong covalent bonds,alloy materials mainly composed of metallic bonding structures typically have great toughness and lower hardness.Breaking through the limits of alloy materials is a preface and long-term topic,which is of great significance and value for improving the comprehensive mechanical properties of alloy materials.Here,we report on the discovery of a cubic alloy semiconducting material Ti_(2)Co with a large Vickers of hardness K_(v)^(exp)∼6.7GPa and low fracture toughness of K_(IC)^(exp)∼1.51MPa·m^(1/2).Unexpectedly,the K_(v)^(exp)∼6.7GPa is nearly triple of the K_(v)^(cal)∼2.66GPa predicted by density functional theory(DFT)calculations and theK_(IC)^(exp)∼1.51MPa·m^(1/2)is about one or two orders of magnitude smaller than that of ordinary titanium alloy materials(K_(IC)^(exp)∼30-120MPa·m^(1/2)).These specifications place Ti_(2)Co far from the phase space of the known alloy materials.Upon incorporation of oxygen into structural void positions,both values were simultaneously improved for Ti_(4)Co_(2)O to∼9.7GPa and∼2.19MPa·m^(1/2),respectively.Further DFT calculations on the electron localization function of Ti_(4)Co_(2)X(X=B,C,N,O)vs.the interstitial elements indicate that these simultaneous improvements originate from the coexistence of Ti-Co metallic bonds,the emergence of newly oriented Ti-X covalent bonds,and the increase of electron concentration.Moreover,the large difference between K_(v)^(exp)and K_(v)^(cal)of Ti_(2)Co suggests underlying mechanism concerning the absence of the O(16d)or Ti_(2)-O bonds in the O-(Ti_(2))_(6) octahedron.This discovery proposes a new pathway to simultaneously improve the comprehensive mechanical performances and illuminates the path of exploring superconducting materials with excellent mechanical performances.
基金This work was supported by the Fund of Fok Ying Tung Edu-cation Foundation,the Major Research Project of Innovative Group of Guizhou province(No.2018-013)Open Fund from Henan Uni-versity of Science and Technology,the National Science Foundation of China(Nos.11964006 and 11774156)the Foundation of the National Key Project for Basic Research(No.2012CB932304)for fi-nancial support。
文摘Previous results revealed that the defect and/or interface had a great impact on the electromagnetic pa-rameters of materials.In order to understand the main physical mechanisms and effectively utilize these strategies,in this study,M Fe_(2)O_(4)and flower-like core@shell M Fe_(2)O_(4)@MoS_(2)(M=Mn,Ni,and Zn)sam-ples with different categories were elaborately designed and selectively produced in large scale through a simple two-step hydrothermal reaction.We conducted the systematical investigation on their microstruc-tures,electromagnetic parameters and microwave absorption performances(MAPs).The obtained results revealed that the large radius of M^(2+)cation could effectively boost the concentration of oxygen vacancy in the M Fe_(2)O_(4)and M Fe_(2)O_(4)@MoS_(2)samples,which resulted in the improvement of dielectric loss capabil-ities and MAPs.Furthermore,the introduction of MoS_(2)nanosheets greatly improved the interfacial effect and enhanced the polarization loss capabilities,which also boosted the MAPs.By taking full advantage of the defect and interface,the designed M Fe_(2)O_(4)@MoS_(2)samples displayed tunable and excellent com-prehensive MAPs including strong absorption capability,wide absorption bandwidth and thin matching thicknesses.Therefore,the clear understanding of defect and interface engineering made these strategies well elaborately designed and applicable to improving MAPs.
基金supported by the Natural Science Foundation of China(No.21174114)the Ministry of Education Plan for Yangtze River Scholar and Innovation Team Development(No.IRT1177)+2 种基金Scientific and Technical Plan Project of Gansu Province(No. 1204GKCA006)the Natural Science Foundation of Gansu Province (No.1010RJZA024)Scientific and Technical Innovation Project of Northwest Normal University(No.nwnu-kjcxgc-03-63)
文摘ZnO/graphene oxide（ZnO/GO） composite material,in which ZnO nanoparticles were densely coated on the GO nanosheets,was successfully prepared by an improved two-step method and characterized by IR, XRD,TEM,and UV-vis techniques.The improved photocatalytic property of the ZnO/GO composite material,evaluated by the photocatalytic degradation of methyl orange（MO） under UV irradiation,is ascribed to the intimate contact between ZnO and GO,the enhanced adsorption of MO,the quick electron transfer from excited ZnO particles to GO sheets and the activation of MO molecules viaπ-πinteraction between MO and GO.
基金Project supported by the National Basic Research Program of China(Grant No.2012CB932302)the National Natural Science Foundation of China(Grant Nos.11634014,51172271,51372269,and 51472264)the“Strategic Priority Research Program”of the Chinese Academy of Sciences(Grant No.XDA09040202)
文摘Continuous CNT fibers have been directly fabricated in a speed of 50 m/h-400 m/h,based on an improved chemical vapor deposition method.As-prepared fibers are further post-treated by acid.According to the SEM images and Raman spectra,the acid treatment results in the compaction and surface modification of the CNTs in fibers,which are beneficial for the electron and load transfer.Compared to the HNO3 treatment,HClSO_3 or H_2SO_4 treatment is more effective for the improvement of the fibers＇ properties.After HCISO_3 treatment for 2 h,the fibers＇ strength and electrical conductivity reach up to-2 GPa and-4.3 MS/m,which are promoted by-200%and almost one order of magnitude than those without acid treatment,respectively.The load-bearing status of the CNT fibers are analyzed based on the downshifts of the G＇ band and the strain transfer factor of the fibers under tension.The results reveal that acid treatment could greatly enhance the load transfer and inter-bundle strength.With the HCISO3 treatment,the strain transfer factor is enhanced from-3.9%to-53.6%.
基金supported by the National Key Science and Technol-ogy Projects in Transportation Industry(Grant number 2021-MS5-127)the Research Program of the Hubei Department of Transportation(Grant number 2020-186-1-3).
文摘Microbial-induced carbonate precipitation(MICP)has emerged as a promising eco-friendly and cost-effective alternative for improving the strength and stability of low-cohesion soils.This review provides an in-depth analysis of the microscopic mechanisms,implementation methods,and macroscopic properties of MICP in soil enhancement.The biogeochemical processes underlying MICP,including urea hydrolysis,denitrification,sulfate reduction,photosynthesis,and iron reduction,are discussed in detail.Various MICP implementation methods,such as two-phase treatment,one-phase treatment,and ex-situ mixing,are reviewed,highlighting their respective advantages and limitations in reinforcing low-cohesion soils.The review also addresses the performance of MICP-treated soils,including improvements in strength,stiffness,permeability,and durability.Furthermore,the key challenges and future prospects for microbial soil reinforcement technologies are summarized.Future research should focus on optimizing nutrient supply,enhancing bacterial retention and activity,controlling the crystallization process,conducting pilot projects,and reducing treatment costs.These efforts are crucial for advancing the practical application of MICP in sustainable infrastructure construction.This review aims to advance the understanding of MICP and its potential for sustainable soil improvement,offering valuable insights for geotechnical engineers.
基金supported by the National Natural Science Foundation of China(51672288,21975273)Taishan Scholars Program of Shandong Province,Dalian National Laboratory for Clean Energy(DICP&QIBEBT No.UN201705)+1 种基金Scientific Research Cooperation Foundation of Qingdao Institute of Bioenergy and Bioprocess TechnologyQingdao Postdoctoral Application Research Project(Project 2018183,2018186)。
文摘We report a simple and effective method to realize desirable interfacial property for inverted planar perovskite solar cells(PSCs)by using small molecule ethanediamine for the construction of a novel polyelectrolyte hole transport material(P3CT-ED HTM).It is found that P3CT-ED can not only improve the hole transport property of P3CT-K but also improve the crystallinity of adjacent perovskite film.In addition,the introduction of ethanediamine into P3CT realigns the conduction and valence bands upwards,passivates surface defects and reduces nonradiative recombination.As a consequence,compared to P3CT-K hole transport layer(HTL)based devices,the average power conversion efficiency(PCE)is boosted from17.2% to 19.6% for the counterparts with P3CT-ED,with simultaneous enhancement in open circuit voltage and fill factor.The resultant device displays a champion PCE of 20.5% with negligible hysteresis.
基金This study was realized thanks to the financial support of the French Region“GrandEst”and the financial and technical support of LERMAB,mainly Stéphane AUBERT for his technical support to build the thermal treatment reactor and the software for regulation and data loggins.LERMAB is supported by a grant overseen by the French National Research Agency(ANR)as part of the“Investissements d’Avenir”Program(ANR-11-LABX-0002-01.Lab of Excellence ARBRE)and is part of ICEEL。
文摘The reduction of the hygroscopicity of wood fibers was investigated through a Thermal Treatment(TT)on wood chips performed before the defibering process.The TT and defibering tests were both carried out on a continuous pilot at semi-industrial scale.The thermal treatment study of wood chips,equivalent to a low temperature pyrolysis,was achieved for four conditions(280°C–320°C)for a duration of 10 min.Mass quantification of solids,condensables and gases(FTIR)at the outcome of the thermal treatment allowed to achieve the mass balances for each condition.The increase of the reactor temperature from 280°C to 320°C leads to a lower solid yield(94%–82%)while gaseous(1%–3.8%)and condensable(3%–11%)products increase significantly.Thermally treated wood samples were afterwards successfully defibered in different conditions to produce suitable fibers for insulation panel production.The aim of the study is also to evaluate the effects of the TT on the lowering of energy consumption necessary for the defibering process while producing good quality fibers.Energy consumption during defibering process shows a significant decrease with the increase the TT severity.Fiber morphology is affected by TT and the morphological quality of the fibers decreases as TT severity increases.The mass percentage of dust was also quantified as a quality marker of produced fibers.Measurements of equilibrium moisture(at 20°C and 65%RH)of the different materials(wood chips before and after TT,produced fibers)show a significant effect of the TT on wood chips hygroscopicity(8.2%for untreated wood to 4.1%for TT at 320°C).However,the effect of the TT on the hygroscopicity reduction of thermally treated wood fibers is drastically less significant due to breaking of the wood structure during defibering process.
基金support from the National Natural Science Foundation of China(Nos.52120105007,51834010)the National Science Fund for Distinguished Young Scholars(No.52222403).
文摘Fracturing fluid property play a critical role in developing unconventional reservoirs.Deep eutectic solvents(DESs)show fascinating potential for property improvement of clean fracturing fluids(CFFs)due to their low-price,low-toxicity,chemical stability and flexible designability.In this work,DESs were synthesized by mixing hydrogen bond acceptors(HBAs)and a given hydrogen bond donor(HBD)to explore their underlying influence on CFF properties based on the intermolecular interactions.The hydrogen-bonding,van der Waals and electrostatic interactions between DES components and surfactants improved the CFF properties by promoting the arrangement of surfactants at interface and enhancing the micelle network strength.The HBD enhanced the resistance of CFF for Ca^(2+) due to coordination-bonding interaction.The DESs composed of choline chloride(ChCl)and malonic acid show great enhancement for surface,rheology,temperature resistance,salt tolerance,drag reduction,and gel-breaking performance of CFFs.The DESs also improved the gel-breaking CFF-oil interactions,increasing the imbibition efficiencies to 44.2%in 74 h.Adjusting HBAs can effectively strengthen the intermolecular interactions(e.g.,HBA-surfactant and HBD-surfactant interactions)to improve CFF properties.The DESs developed in this study provide a novel strategy to intensify CFF properties.
基金supported by the National Natural Science Foundation of China(Nos.51908457 and 52070155).
文摘This study investigates the use of struviterient-loaded magnesium-modified biochar beads(Ca/MgBC+NP)as a slow-release fertilizer and soil amendment,comparing its performance with commercially available slow-release fertilizers(SRF)in different soils and crop types.The results demonstrate that Ca/MgBC+NP exhibited satisfying swelling,water retention,and slow-release properties in all tested soils.In sandy soil,which showed the most significant differences(p<0.05),Ca/MgBC+NP enhanced the growth of Brassica chinensis L.and Spinacia oleracea L.after 90 d,with shoot and root lengths,as well as fresh and dry weights,1.25-2.84 times higher than those treated with SRF.The cation exchange capacity and organic carbon content of sandy soil were significantly improved(by 38.55%and 265.38%),overcoming its natural limitations in water and fertilizer retention.Principal Component Analysis(PCA)confirmed that soil properties played a crucial role in crop growth(52.67%variance explained).Spectroscopic analysis indicated that magnesium-related compounds,including struvite and Mg(PO_(4))_(3),contributed to the observed growth promotion.Furthermore,Ca/MgBC+NP effectively immobilized heavy metals,particularly Cr and Hg,with immobilization rates exceeding 80%.This study highlights the potential of Ca/MgBC+NP as a sustainable,low-cost fertilizer that not only enhances crop growth but also improves soil health and remediates heavy metal contamination,providing a promising alternative for green agriculture.
基金supported by the National Natural Science Foundation of China(61474047,52372190,52372191,22271106)the Natural Science Foundation of Fujian Province(2023J01116)+1 种基金the Guangdong Basic and Applied Basic Research Foundation(2024A1515011923)the Talent Project of Lingnan Normal University(ZL22046)。
文摘The power conversion efficiency(PCE)and stability of organic-inorganic hybrid perovskite solar cells(PSCs)are limited by the energy level mismatches and substantial defects.Interface engineering is a reliable strategy for solving these problems.Here,we synthesized three small dipole molecules,named PzT-TPA,PzTA-TPA,and PzTA-TPAS,which were introduced into the interface between the perovskite and the hole-transport layers.The advantages of the interface dipole material included regulating the energy band structure,enhancing the built-in electric field and promoting the carrier transport.Compared with the pristine device,the PzTA-TPAS-treated device showed significantly improved photoelectric properties,including an optimal PCE of 25.55%,an impressive open-circuit voltage(V_(OC))of 1.177 V and an excellent operational stability.
基金the Fund of Fok Ying Tung Education Foundation,the Natural Science Foundation of Guizhou province(No.2017-1034)the Major Research Project of innovative Group of Guizhou province(No.2018-013)+1 种基金the Natural National Science Foundation of China(Nos.11604060,52101010,and 11964006)the Foundation of the National Key Project for Basic Research(No.2012CB932304)for financial support.
文摘Defect and interface engineering are efficient approaches to adjust the physical and chemical properties of nanomaterials.In order to effectively utilize these strategies for the improvement of microwave absorption properties(MAPs),in this study,we reported the synthesis of hollow carbon shells and hollow carbon@MoS_(2)nanocomposites by the template-etching and templateetching-hydrothermal methods,respectively.The obtained results indicated that the degree of defect for hollow carbon shells and hollow carbon@MoS_(2)could be modulated by the thickness of hollow carbon shell,which effectively fulfilled the optimization of electromagnetic parameters and improvement of MAPs.Furthermore,the microstructure investigations revealed that the precursor of hollow carbon shells was encapsulated by the sheet-like MoS_(2)in high efficiency.And the introduction of MoS_(2)nanosheets acting as the shell effectively improved the interfacial effects and boosted the polarization loss capabilities,which resulted in the improvement of comprehensive MAPs.The elaborately designed hollow carbon@MoS_(2)samples displayed very outstanding MAPs including strong absorption capabilities,broad absorption bandwidth,and thin matching thicknesses.Therefore,this work provided a viable strategy to improve the MAPs of microwave absorbers by taking full advantage of their defect and interface engineering.
