Rechargeable magnesium-ion batteries(MIBs) are favorable substitutes for conventional lithium-ion batteries(LIBs) because of abundant magnesium reserves, a high theoretical energy density, and great inherent safety. O...Rechargeable magnesium-ion batteries(MIBs) are favorable substitutes for conventional lithium-ion batteries(LIBs) because of abundant magnesium reserves, a high theoretical energy density, and great inherent safety. Organic electrode materials with excellent structural tunability,unique coordination reaction mechanisms, and environmental friendliness offer great potential to promote the electrochemical performance of MIBs. However, research on organic magnesium battery cathode materials is still preliminary with many significant challenges to be resolved including low electrical conductivity and unwanted but severe dissolution in useful electrolytes. Herein, we provide a detailed overview of reported organic cathode materials for MIBs. We begin with basic properties such as charge storage mechanisms(e.g., n-, p-, and bipolartype), moving to recent advances in various types of organic cathodes including carbonyl-, nitrogen-, and sulfur-based materials. To shed light on the diverse strategies targeting high-performance Mg-organic batteries, elaborate summaries of various approaches are presented.Generally, these strategies include molecular design, polymerization, mixing with carbon, nanosizing and electrolyte/separator optimization.This review provides insights on exploring high-performance organic cathodes in rechargeable MIBs.展开更多
The rationally designed ruthenium selenide(RuSe_(1.6)-500)nanocomposite with selenium vacancies was synthesized via a hydrothermal/annealing approach.During the annealing step,calcination under a H_(2)/Ar atmosphere f...The rationally designed ruthenium selenide(RuSe_(1.6)-500)nanocomposite with selenium vacancies was synthesized via a hydrothermal/annealing approach.During the annealing step,calcination under a H_(2)/Ar atmosphere facilitated the evaporation of selenium,thereby generating selenium vacancies.This study confirmed that RuSe_(1.6)-500 prepared by this method functions as an efficient electrocatalyst for the hydrogen evolution reaction(HER)in seawater.Furthermore,experiments and density functional theory calculations demonstrated that the enhanced electrocatalytic performance and resistance to Cl-induced corrosion in seawater can be attributed to the surface reconstruction of RuSe_(1.6)-500 during the HER process.Specifically,the reconstruction involves the adsorption of hydroxyl groups at selenium vacancies,leading to the formation of a hydroxy-rich surface on RuSe_(1.6)-500.The hydroxy-rich surface is responsible for the superior electrocatalytic activity and stability of RuSe_(1.6)-500 as an electrocatalyst for the HER in seawater.展开更多
Recent advancements in Zn-halogen batteries have focused on enhancing the adsorptive or catalytic capability of host materials and stabilizing complex intermediates with electrolyte additives,while the halogen-ion ele...Recent advancements in Zn-halogen batteries have focused on enhancing the adsorptive or catalytic capability of host materials and stabilizing complex intermediates with electrolyte additives,while the halogen-ion electrolyte modifications exhibit strong potential for integrated interfacial regulation.Herein,we design an electrically insulating rigid electrolyte container to immobilize a liquid halogen-ion electrolyte for separator-free Zn-halogen batteries with customizable electron transfer.Robust hydrogen bonding of hydroxyl groups in SiO_(2)with fluorinated moieties in PVDF-hfp regulates Zn^(2+)solvation and suppresses H_(2)O activity,while multi-channels formed by microcracks and interparticle gaps not only enhance mass transfer but also buffer interfacial electric field,jointly enabling a durable Zn plating/stripping.Effective confinement of intermediates also ensures the high reversibility across single-(I^(-)/I0),double-(I^(-)/I0/I^(-)),and triple-(I^(-)/I0/I^(-),Cl-/Cl0)electron transfer mechanisms at cathode,as evidenced by the double-electron transfer systems exhibiting a low capacity decay rate of 0.02‰over 4500 cycles at 10 mA cm^(-2)and a high areal capacity of 11.9 mAh cm^(-2)at 2 mA cm^(-2).This work presents a novel“container engineering”approach to halogen-ion electrolyte design and provides fundamental insights into the relationships between redox reversibility and reaction kinetics.展开更多
With the depletion of fossil fuels and global warming,there is an urgent demand to seek green,low-cost,and high-efficiency energy resources.Hydrogen has been considered as a potential candidate to replace fossil fuels...With the depletion of fossil fuels and global warming,there is an urgent demand to seek green,low-cost,and high-efficiency energy resources.Hydrogen has been considered as a potential candidate to replace fossil fuels,due to its high gravimetric energy density(142 MJ kg^(-1)),high abundance(H_(2)O),and environmentalfriendliness.However,due to its low volume density,effective and safe hydrogen storage techniques are now becoming the bottleneck for the"hydrogen economy".Under such a circumstance,Mg-based hydrogen storage materials garnered tremendous interests due to their high hydrogen storage capacity(~7.6 wt%for MgH_(2)),low cost,and excellent reversibility.However,the high thermodynamic stability(ΔH=-74.7 kJ mol^(-1)H_(2))and sluggish kinetics result in a relatively high desorption temperature(>300℃),which severely restricts widespread applications of MgH_(2).Nano-structuring has been proven to be an effective strategy that can simultaneously enhance the ab/de-sorption thermodynamic and kinetic properties of MgH_(2),possibly meeting the demand for rapid hydrogen desorption,economic viability,and effective thermal management in practical applications.Herein,the fundamental theories,recent advances,and practical applications of the nanostructured Mg-based hydrogen storage materials are discussed.The synthetic strategies are classified into four categories:free-standing nano-sized Mg/MgH_(2)through electrochemical/vapor-transport/ultrasonic methods,nanostructured Mg-based composites via mechanical milling methods,construction of core-shell nano-structured Mg-based composites by chemical reduction approaches,and multi-dimensional nano-sized Mg-based heterostructure by nanoconfinement strategy.Through applying these strategies,near room temperature ab/de-sorption(<100℃)with considerable high capacity(>6 wt%)has been achieved in nano Mg/MgH_(2)systems.Some perspectives on the future research and development of nanostructured hydrogen storage materials are also provided.展开更多
The compositional heterogeneity in high-entropy alloys(HEAs)has been reported to be an inherent en-tity,which significantly alters the mechanical properties of materials by tuning the variation of lattice resistance f...The compositional heterogeneity in high-entropy alloys(HEAs)has been reported to be an inherent en-tity,which significantly alters the mechanical properties of materials by tuning the variation of lattice resistance for dislocation motion.However,since the body-centered cubic(BCC)structure is not close-packed,the change of lattice resistance is less sensitive to the normal concentration wave compared to that in face-centered cubic(FCC)structured materials.In this work,we selected a refractory bcc HEAs TiZrNbTa for the matrix and added a small amount of Al to facilitate the special spinodal decomposition structure.In particular,(TiZrNbTa)98.5 Al 1.5 displayed a typical basket-weave fabric morphology of spinodal decomposition structure with a characteristic periodicity of∼8 nm and had an optimal combination of strength and ductility(the yield strength of 1123±9 MPa and ductility of∼20.7%±0.6%).It was de-termined that by doing in situ TEM mechanical testing,the plastic deformation was dominated by the formation and operation of dislocation loops which provided both edge and screw components of dislo-cations.The synergetic effect of the remarkable chemical heterogeneity created by the spinodal decompo-sition and the spreading lattice distortion in high entropy alloys is quite effective in tuning the mobility of different types of dislocations and facilitates dislocation interactions,enabling the combination of high strength and ductility.展开更多
The formation of bulk metallic glasses（BMGs） in the ternary Zr（56） Co（28-x）Al（16） and quaternary Zr（56） Co（28-x）CuxAl16（x=2, 4, 5, 6, 7, mole fraction, %） glassy alloys was investigated via the copper mo...The formation of bulk metallic glasses（BMGs） in the ternary Zr（56） Co（28-x）Al（16） and quaternary Zr（56） Co（28-x）CuxAl16（x=2, 4, 5, 6, 7, mole fraction, %） glassy alloys was investigated via the copper mold suction casting method. The main purpose of this work was to locate the optimal BMG-forming composition for the quaternary Zr Co（Cu）Al alloys and to improve the plasticity of the parent alloy. The X-ray diffractometry（XRD）, transmission electron microscopy（TEM） and differential scanning calorimetry（DSC） were used to investigate the glassy alloys structure and their glass forming ability（GFA）. In addition, the compression test, microhardness, nano-indentation and scanning electron microscopy（SEM） were utilized to discuss the possible mechanisms involved in the enhanced plasticity achievement. The highest GFA among Cu-containing alloys was found for the Zr（56） Co（22） Cu6 Al（16） alloy, which was similar to that of the base alloy. Furthermore, the plasticity of the base alloy increased significantly from 3.3% to 6% for the Zr（56） Co（22） Cu）6 Al（16） BMG. The variations in the plasticity and GFA of the alloys were discussed by considering the positive heat of mixing within Cu and Co elements.展开更多
Cu–15%NbC (volume fraction) powder was synthesized using the starting powders of Cu, Nb and graphite in a high energy vibratory disc mill for 7 h of milling under argon atmosphere. A composite sample and a C...Cu–15%NbC (volume fraction) powder was synthesized using the starting powders of Cu, Nb and graphite in a high energy vibratory disc mill for 7 h of milling under argon atmosphere. A composite sample and a Cu/NbC functionally graded material (FGM) sample were produced by using the two-step press and sintering at 900 °C for 1 h under vacuum. The microstructure and physical and mechanical properties of the specimens were investigated. The field emission scanning electron microscopy, energy dispersive X-ray and X-ray diffraction analysis confirmed the synthesis of the nanostructure matrix of 18–27 nm with the nanoparticles reinforcement of 42 nm after sintering, verifying the thermal stability of this composite at high temperature. The hardness of Cu–15%NbC was five times greater than that of the pure Cu specimen. The volume reduction of the sample after the wear test decreased in comparison with the pure Cu specimen. The electrical conductivity of the composite specimen decreased to 36.68% IACS. The FGM specimen exhibited high electrical conductivity corresponding to 75.83% IACS with the same hardness and wear properties as those of the composite sample on the composite surface. Thus, Cu/NbC FGM with good mechanical and electrical properties can be a good candidate for electrical contact applications.展开更多
The limited lithium resource in earth's crust has stimulated the pursuit of alternative energy storage technologies to lithium-ion battery.Potassium-ion batteries(KIBs)are regarded as a kind of promising candidate...The limited lithium resource in earth's crust has stimulated the pursuit of alternative energy storage technologies to lithium-ion battery.Potassium-ion batteries(KIBs)are regarded as a kind of promising candidate for large-scale energy storage owing to the high abundance and low cost of potassium resources.Nevertheless,further development and wide application of KIBs are still challenged by several obstacles,one of which is their fast capacity deterioration at high rates.A considerable amount of effort has recently been devoted to address this problem by developing advanced carbonaceous anode materials with diverse structures and morphologies.This review presents and highlights how the architecture engineering of carbonaceous anode materials gives rise to high-rate performances for KIBs,and also the beneficial conceptions are consciously extracted from the recent progress.Particularly,basic insights into the recent engineering strategies,structural innovation,and the related advances of carbonaceous anodes for high-rate KIBs are under specific concerns.Based on the achievements attained so far,a perspective on the foregoing,and proposed possible directions,and avenues for designing high-rate anodes,are presented finally.展开更多
The contributions of different strengthening mechanisms to yield strength of bainite/martensite multiphase rail steel with different finish cooling temperatures in the controlled cooling process were quantitatively in...The contributions of different strengthening mechanisms to yield strength of bainite/martensite multiphase rail steel with different finish cooling temperatures in the controlled cooling process were quantitatively investigated.Dislocation density and substructure size of the rail steel were measured by scanning electron microscopy,electron backscatter diffraction and X-ray diffraction.The results show that the dislocation density increases with the decrease in block width in rail steel.Based on the correlation among dislocation density,block width and yield strength,a physical model was proposed to predict the yield strength of rail steel.The variation of block width and dislocation density in different positions of rail head microstructure was integrated with temperature field simulation.Dislocation density and block width reveal significant correlations with the finish cooling temperature.展开更多
In low-density steel,κ-carbides primarily precipitate in the form of nanoscale particles within austenite grains.However,their precipitation within ferrite matrix grains has not been comprehensively explored,and the ...In low-density steel,κ-carbides primarily precipitate in the form of nanoscale particles within austenite grains.However,their precipitation within ferrite matrix grains has not been comprehensively explored,and the second-phase evolution mechanism during aging remains unclear.In this study,the crystallographic characteristics and morphological evolution ofκ-carbides in Fe-28Mn-10Al-0.8C(wt%)low-density steel at different aging temperatures and times and the impacts of these changes on the steels’microhardness and properties were comprehensively analyzed.Under different heat treatment conditions,intragranularκ-carbides exhibited various morpho-logical and crystallographic characteristics,such as acicular,spherical,and short rod-like shapes.At the initial stage of aging,acicularκ-carbides primarily precipitated,accompanied by a few spherical carbides.κ-Carbides grew and coarsened with aging time,the spherical carbides were considerably reduced,and rod-like carbides coarsened.Vickers hardness testing demonstrated that the material’s hardness was affected by the volume fraction,morphology,and size ofκ-carbides.Extended aging at higher temperatures led to an increase in carbide size and volume fraction,resulting in a gradual rise in hardness.During deformation,the primary mechanisms for strengthening were dislocation strengthening and second-phase strengthening.Based on these findings,potential strategies for improving material strength are proposed.展开更多
In-situ electron irradiation and aging are applied to introduce high-density precipitates in an Mg-10Gd-3Y-1Zn-0.5Zr(GWZ1031K,wt.%)alloy to improve the hardness.The results show that the hardness of the Mg alloy after...In-situ electron irradiation and aging are applied to introduce high-density precipitates in an Mg-10Gd-3Y-1Zn-0.5Zr(GWZ1031K,wt.%)alloy to improve the hardness.The results show that the hardness of the Mg alloy after irradiation for 10 h and aging for 9 h at 250℃ is 1.64 GPa,which is approximately 64% higher than that of the samples before being treated.It is mainly attributed to γ'precipitates on the basal plane after irradiation and the high-density nanoscale β'precipitates on the prismatic plane after aging,which should be closely related to the irradiation-induced homogenous clusters.The latter plays a key role in precipitation hardening.This result paves a way to improve the mechanical properties of metallic materials by tailoring the precipitation through irradiation and aging.展开更多
The cast-decant-cast is a new method for the preparation of the functionally graded components that has been developed in recent years. The functionally graded cylindrical shape component with a radial gradient, e.g. ...The cast-decant-cast is a new method for the preparation of the functionally graded components that has been developed in recent years. The functionally graded cylindrical shape component with a radial gradient, e.g. the first alloy （A390） with high wear resistance on the surface of the piece and toughness and the second alloy （A356） of low machining costs in the core of the piece can be produced via this melt process. The effect of the second alloy superheat at temperatures of 750, 820 and 860 ℃ as well as the effect of the first alloy solidified layer at 25, 35 and 45 s decanting time on achieving the perfect interface between the two alloys was investigated. The characterization of the interface was carded out by optical microscopy and scanning electron microscopy, and its width was measured by the microhardness test. The results showed that the best interface was obtained at 860 ℃ and 35 s decanting time with a width of 500 ~tm. Also, the wear resistance test was performed to measure and compare the surface wear resistance to the core.展开更多
Chemotherapy is still a kind of important strategy for cancer treatment,but lacking effective delivery system limits the therapeutic outcome.Owing to the excellent biocompatibility,albumin has been employed as drug ve...Chemotherapy is still a kind of important strategy for cancer treatment,but lacking effective delivery system limits the therapeutic outcome.Owing to the excellent biocompatibility,albumin has been employed as drug vehicle;however,it has to face complicated synthesis procedures and still needs an effective technology for the drug delivery evaluation.In this study,a facile method was utilized to prepare a protein-based theranostic system through the self-assembly of albumins with small molecules and drugs;furthermore,the paramagnetic divalent manganese ions were conjugated on the surface of the nanocomposite through a coordination bond and carried out the magnetic resonance imaging.This nanosystem with a stable structure exhibited about 80 nanometer size and 7.7[Mn]mM-1S-1 T1 relaxivity;moreover,the pH-sensitive drug releasing property and the imaging function empower it with theranostic cancer therapy.Moreover,the nanocomposites effectively entered into the cancer cells and showed superior antitumor ability;and these treated cells exhibited significant T1 signal.These results suggested that the albumin-based nanosystem is a novel chemotherapy drug delivery vehicle and a promising candidate for magnetic resonance imaging.展开更多
A new concentrated ternary salt ether-based electrolyte enables stable cycling of lithium metal battery(LMB)cells with high-mass-loading(13.8 mg cm^(−2),2.5 mAh cm^(−2))NMC622(LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2))cathodes ...A new concentrated ternary salt ether-based electrolyte enables stable cycling of lithium metal battery(LMB)cells with high-mass-loading(13.8 mg cm^(−2),2.5 mAh cm^(−2))NMC622(LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2))cathodes and 50μm Li anodes.Termed“CETHER-3,”this electrolyte is based on LiTFSI,LiDFOB,and LiBF4 with 5 vol%fluorinated ethylene carbonate in 1,2-dimethoxyethane.Commer-cial carbonate and state-of-the-art binary salt ether electrolytes were also tested as baselines.With CETHER-3,the electrochemical performance of the full-cell battery is among the most favorably reported in terms of high-voltage cycling stability.For example,LiNi_(x)Mn_(y)Co_(1-x-y)O_(2)(NMC)-Li metal cells retain 80%capacity at 430 cycles with a 4.4 V cut-off and 83%capacity at 100 cycles with a 4.5 V cut-off(charge at C/5,discharge at C/2).According to simulation by density functional theory and molecular dynamics,this favorable performance is an outcome of enhanced coordination between Li^(+)and the solvent/salt molecules.Combining advanced microscopy(high-resolution transmission electron microscopy,scanning electron microscopy)and surface science(X-ray photoelectron spectroscopy,time-of-fight secondary ion mass spectroscopy,Fourier-transform infrared spectroscopy,Raman spectroscopy),it is demonstrated that a thinner and more stable cathode electrolyte interphase(CEI)and solid electrolyte interphase(SEI)are formed.The CEI is rich in lithium sulfide(Li_(2)SO_(3)),while the SEI is rich in Li_(3)N and LiF.During cycling,the CEI/SEI suppresses both the deleterious transformation of the cathode R-3m layered near-surface structure into disordered rock salt and the growth of lithium metal dendrites.展开更多
The dry friction and wear characteristics of rare earth/MoSi 2 composite against 45 steel under different loads were investigated by using an M 200 type friction and wear tester. SEM and XRD were used to analyze the...The dry friction and wear characteristics of rare earth/MoSi 2 composite against 45 steel under different loads were investigated by using an M 200 type friction and wear tester. SEM and XRD were used to analyze the morphology of the friction surface and the phase of worn piece in order to reveal the wear mechanism of rare earth/MoSi 2 composite. Results show that the relationships of friction coefficient, μ , or wear rate, W , of MoSi 2 and RE/MoSi 2 composite to loads, p , can be fitted well with the following function: μ (or W )= a+bp+cp 2+dp 3+ep 4 , where a, b, c, d and e are fitting constants depending on materials and confidence. MoSi 2 and rare earth/MoSi 2 composite have excellent wear resistance. When load is in the range of 80～120 N, the wear rate of RE/MoSi 2 composite is lower than that of MoSi 2 material by about 65%. The main wear mechanism of rare earth/MoSi 2 composite is adhesive wear.展开更多
The dry friction and wear properties of intermetallics MoSi 2 against 45 steel under different loads were investigated with M 2 type friction and wear tester. Scanning electric microscope (SEM) equipment with micropro...The dry friction and wear properties of intermetallics MoSi 2 against 45 steel under different loads were investigated with M 2 type friction and wear tester. Scanning electric microscope (SEM) equipment with microprobe was employed to analyze the morphology of the friction surface. Results show that the dry friction and wear properties are deeply affected by load. The wear rate of MoSi 2 at the load of 80?N is the maximum which is 36.1?μg/m. On the condition of the load of 150?N, MoSi 2 material has the better friction and wear properties: friction coefficient is 0.28 and wear rate is 10.6?μg/m. With the load increasing, the main friction mechanisms change from microslip and plastic deformation to adhesive effect, and the main wear mechanisms change from plough groove wear and oxidation fatigue wear to adhesive wear.展开更多
The role of melt cooling rate on the interface morphology and dislocation configuration between 18R long-period stacking ordered(LPSO)structure and Mg matrix in Mg_(97)Zn_(1)Y_(2)(at.%)alloys was investigated by atomi...The role of melt cooling rate on the interface morphology and dislocation configuration between 18R long-period stacking ordered(LPSO)structure and Mg matrix in Mg_(97)Zn_(1)Y_(2)(at.%)alloys was investigated by atomic-scale HAADF-STEM imaging.The 18R/Mg interface is step-like both in the near-equilibrium alloy and non-equilibrium alloy.Lower cooling rate makes the step size more regular and larger.Only 54R structure can be observed at the interface in the near-equilibrium alloy,and the dislocations are highly ordered.54R and 54R′structure sandwiched by b1 and b2+b3 dislocation arrays,and new dislocation configuration can be detected at the interface in the non-equilibrium alloy,but the dislocations are less ordered.18R/Mg interface containing 54R or 54R′in equilibrium width,parallel to the(010)plane,should be most stable based on elastic calculation.The segregation of solute atoms and its strong interaction with dislocations dominate the LPSO/Mg interface via diffusion-displacive transformation.展开更多
In this study,the fibers of invasive species Agave americana L.and Ricinus communis L.were successfully used for the first time as new sources to produce cytocompatible and highly crystalline cellulose nanofibers.Cell...In this study,the fibers of invasive species Agave americana L.and Ricinus communis L.were successfully used for the first time as new sources to produce cytocompatible and highly crystalline cellulose nanofibers.Cellulose nanofibers were obtained by two methods,based on either alkaline or acid hydrolysis.The morphology,chemical composition,and crystallinity of the obtained materials were characterized by scanning electron microscopy(SEM)together with energy-dispersive X-ray spectroscopy(EDX),dynamic light scattering(DLS),X-ray diffraction(XRD),and Fourier transform infrared(FTIR)spectroscopy.The crystallinity indexes(CIs)of the cellulose nanofibers extracted from A.americana and R.communis were very high(94.1%and 92.7%,respectively).Biological studies evaluating the cytotoxic effects of the prepared cellulose nanofibers on human embryonic kidney 293 T(HEK293 T)cells were also performed.The nanofibers obtained using the two different extraction methods were all shown to be cytocompatible in the concentration range assayed(i.e.,0-500μg/mL).Our results showed that the nanocellulose extracted from A.americana and R.communis fibers has high potential as a new renewable green source of highly crystalline cellulose-based cytocompatible nanomaterials for biomedical applications.展开更多
Nanoporous Ag-Pt bi-metallic alloy was fabricated by free dealloying of amorphous Ag-based precursor with the nominal composition of Ag38.25Pt0.5Cu38.75Si22.5.The noble Ag and Pt were left after the less noble Cu and ...Nanoporous Ag-Pt bi-metallic alloy was fabricated by free dealloying of amorphous Ag-based precursor with the nominal composition of Ag38.25Pt0.5Cu38.75Si22.5.The noble Ag and Pt were left after the less noble Cu and Si dissolved in a certain acid solution.Bi-continuous nanoporous microstructure was formed with asymmetric ligaments and pores with typically 30-200 nm in width.The trace addition of Pt has refined the grains of the ligaments to the average size of less than 20 nm in the substrate and induced the formation of rods with nanopores.The morphologies of the rods were observed by scanning electron microscopy(SEM)and transmission electron microscopy(TEM)both in the form of clusters and as scattered individuals with characteristic length of several micrometers and diameter of tens of nanometers.The grains sizes in the rods were finer than those in the ligaments.The good mechanical integrity might be due to the combination of continuous ligaments and clusters of rods.展开更多
The impregnation of nanoparticles magnetified into wood had been developed by different methods,like surface chemical coprecipitation and vacuum-pressure coprecipitation of magnetic nanoparticles(NPs).However,there is...The impregnation of nanoparticles magnetified into wood had been developed by different methods,like surface chemical coprecipitation and vacuum-pressure coprecipitation of magnetic nanoparticles(NPs).However,there is a lack of information on the best method to coprecipitation NPs.Then,the present study has the objective to measure the effects of the impregnation process of wood veneers through two in situ processes(immersion and vacuum-pressure)using a solution of FeCl_(3)·6H_(2)O,FeCl_(2)·4H_(2)O and ammonia in three tropical species(Pinus oocarpa,Vochysia ferruginea and Vochysia guatemalensis).It was measured the degree of synthesis of iron NPs using weight and density gains,Fe^(3+) absorption,emission scanning electron microscope(SEM),Fournier transform infrared spectroscopy(FT-IR)and for magnetic properties were measured using vibrating sample magnetometry(VSM).After 5-layer veneer panels were fabricated,we evaluated their physical and mechanical properties.Wood samples impregnated by vacuum-pressure methods showed the higher amount of Fe_(3)O_(4)NPs formation,which was observed in the SEM,X-ray diffraction(XDR),FT-IR and VSM.Vacuum-pressure on treatment presented higher ferrite signals and better magnetic properties.Vochysia ferruginea presented the greatest magnetization properties.The magnetization treated causes probably a degradation of the cell wall,which weakens its mechanical properties,especially internal bonding.展开更多
基金the support from the National Key Research & Development Program (2022YFB3803700) of ChinaNational Natural Science Foundation (No.52171186)the support from the Center of Hydrogen Science,Shanghai Jiao Tong University。
文摘Rechargeable magnesium-ion batteries(MIBs) are favorable substitutes for conventional lithium-ion batteries(LIBs) because of abundant magnesium reserves, a high theoretical energy density, and great inherent safety. Organic electrode materials with excellent structural tunability,unique coordination reaction mechanisms, and environmental friendliness offer great potential to promote the electrochemical performance of MIBs. However, research on organic magnesium battery cathode materials is still preliminary with many significant challenges to be resolved including low electrical conductivity and unwanted but severe dissolution in useful electrolytes. Herein, we provide a detailed overview of reported organic cathode materials for MIBs. We begin with basic properties such as charge storage mechanisms(e.g., n-, p-, and bipolartype), moving to recent advances in various types of organic cathodes including carbonyl-, nitrogen-, and sulfur-based materials. To shed light on the diverse strategies targeting high-performance Mg-organic batteries, elaborate summaries of various approaches are presented.Generally, these strategies include molecular design, polymerization, mixing with carbon, nanosizing and electrolyte/separator optimization.This review provides insights on exploring high-performance organic cathodes in rechargeable MIBs.
基金supported by the National Key Research and Development Program of China(2022YFB3805600,2022YFB3805604)the National Natural Science Foundation of China(52201286)+3 种基金the National 111 Project(B20002)the Key R&D Program of Shandong Province,China(2023CXGC010314)the Hubei Provincial Natural Science Foundation of China(2024AFB195)the Fundamental Research Funds for the Central Universities(104972025KFYzxk0014,104972024KFYjlb0008)。
文摘The rationally designed ruthenium selenide(RuSe_(1.6)-500)nanocomposite with selenium vacancies was synthesized via a hydrothermal/annealing approach.During the annealing step,calcination under a H_(2)/Ar atmosphere facilitated the evaporation of selenium,thereby generating selenium vacancies.This study confirmed that RuSe_(1.6)-500 prepared by this method functions as an efficient electrocatalyst for the hydrogen evolution reaction(HER)in seawater.Furthermore,experiments and density functional theory calculations demonstrated that the enhanced electrocatalytic performance and resistance to Cl-induced corrosion in seawater can be attributed to the surface reconstruction of RuSe_(1.6)-500 during the HER process.Specifically,the reconstruction involves the adsorption of hydroxyl groups at selenium vacancies,leading to the formation of a hydroxy-rich surface on RuSe_(1.6)-500.The hydroxy-rich surface is responsible for the superior electrocatalytic activity and stability of RuSe_(1.6)-500 as an electrocatalyst for the HER in seawater.
基金supported by the Science Fund for Distinguished Young Scholars of Hunan Province(2023JJ10060)the National Natural Science Foundation of China(22575269)Young Elite Scientists Sponsorship Program by CAST(2023QNRC001)。
文摘Recent advancements in Zn-halogen batteries have focused on enhancing the adsorptive or catalytic capability of host materials and stabilizing complex intermediates with electrolyte additives,while the halogen-ion electrolyte modifications exhibit strong potential for integrated interfacial regulation.Herein,we design an electrically insulating rigid electrolyte container to immobilize a liquid halogen-ion electrolyte for separator-free Zn-halogen batteries with customizable electron transfer.Robust hydrogen bonding of hydroxyl groups in SiO_(2)with fluorinated moieties in PVDF-hfp regulates Zn^(2+)solvation and suppresses H_(2)O activity,while multi-channels formed by microcracks and interparticle gaps not only enhance mass transfer but also buffer interfacial electric field,jointly enabling a durable Zn plating/stripping.Effective confinement of intermediates also ensures the high reversibility across single-(I^(-)/I0),double-(I^(-)/I0/I^(-)),and triple-(I^(-)/I0/I^(-),Cl-/Cl0)electron transfer mechanisms at cathode,as evidenced by the double-electron transfer systems exhibiting a low capacity decay rate of 0.02‰over 4500 cycles at 10 mA cm^(-2)and a high areal capacity of 11.9 mAh cm^(-2)at 2 mA cm^(-2).This work presents a novel“container engineering”approach to halogen-ion electrolyte design and provides fundamental insights into the relationships between redox reversibility and reaction kinetics.
基金support from the National Key Research&Development Program(2022YFB3803700)of ChinaNational Natural Science Foundation(No.52171186)financial support from the Center of Hydrogen Science,Shanghai Jiao Tong University。
文摘With the depletion of fossil fuels and global warming,there is an urgent demand to seek green,low-cost,and high-efficiency energy resources.Hydrogen has been considered as a potential candidate to replace fossil fuels,due to its high gravimetric energy density(142 MJ kg^(-1)),high abundance(H_(2)O),and environmentalfriendliness.However,due to its low volume density,effective and safe hydrogen storage techniques are now becoming the bottleneck for the"hydrogen economy".Under such a circumstance,Mg-based hydrogen storage materials garnered tremendous interests due to their high hydrogen storage capacity(~7.6 wt%for MgH_(2)),low cost,and excellent reversibility.However,the high thermodynamic stability(ΔH=-74.7 kJ mol^(-1)H_(2))and sluggish kinetics result in a relatively high desorption temperature(>300℃),which severely restricts widespread applications of MgH_(2).Nano-structuring has been proven to be an effective strategy that can simultaneously enhance the ab/de-sorption thermodynamic and kinetic properties of MgH_(2),possibly meeting the demand for rapid hydrogen desorption,economic viability,and effective thermal management in practical applications.Herein,the fundamental theories,recent advances,and practical applications of the nanostructured Mg-based hydrogen storage materials are discussed.The synthetic strategies are classified into four categories:free-standing nano-sized Mg/MgH_(2)through electrochemical/vapor-transport/ultrasonic methods,nanostructured Mg-based composites via mechanical milling methods,construction of core-shell nano-structured Mg-based composites by chemical reduction approaches,and multi-dimensional nano-sized Mg-based heterostructure by nanoconfinement strategy.Through applying these strategies,near room temperature ab/de-sorption(<100℃)with considerable high capacity(>6 wt%)has been achieved in nano Mg/MgH_(2)systems.Some perspectives on the future research and development of nanostructured hydrogen storage materials are also provided.
基金supported by the National Natu-ral Science Foundation of China(Nos.51871197,52171166,and U20A20231)the Higher Education Discipline Innovation Project(No.B16042)the National Key Research and Development Program of China(No.2017YFA0208200).
文摘The compositional heterogeneity in high-entropy alloys(HEAs)has been reported to be an inherent en-tity,which significantly alters the mechanical properties of materials by tuning the variation of lattice resistance for dislocation motion.However,since the body-centered cubic(BCC)structure is not close-packed,the change of lattice resistance is less sensitive to the normal concentration wave compared to that in face-centered cubic(FCC)structured materials.In this work,we selected a refractory bcc HEAs TiZrNbTa for the matrix and added a small amount of Al to facilitate the special spinodal decomposition structure.In particular,(TiZrNbTa)98.5 Al 1.5 displayed a typical basket-weave fabric morphology of spinodal decomposition structure with a characteristic periodicity of∼8 nm and had an optimal combination of strength and ductility(the yield strength of 1123±9 MPa and ductility of∼20.7%±0.6%).It was de-termined that by doing in situ TEM mechanical testing,the plastic deformation was dominated by the formation and operation of dislocation loops which provided both edge and screw components of dislo-cations.The synergetic effect of the remarkable chemical heterogeneity created by the spinodal decompo-sition and the spreading lattice distortion in high entropy alloys is quite effective in tuning the mobility of different types of dislocations and facilitates dislocation interactions,enabling the combination of high strength and ductility.
基金Iran University of Science and Technology for the financial support
文摘The formation of bulk metallic glasses（BMGs） in the ternary Zr（56） Co（28-x）Al（16） and quaternary Zr（56） Co（28-x）CuxAl16（x=2, 4, 5, 6, 7, mole fraction, %） glassy alloys was investigated via the copper mold suction casting method. The main purpose of this work was to locate the optimal BMG-forming composition for the quaternary Zr Co（Cu）Al alloys and to improve the plasticity of the parent alloy. The X-ray diffractometry（XRD）, transmission electron microscopy（TEM） and differential scanning calorimetry（DSC） were used to investigate the glassy alloys structure and their glass forming ability（GFA）. In addition, the compression test, microhardness, nano-indentation and scanning electron microscopy（SEM） were utilized to discuss the possible mechanisms involved in the enhanced plasticity achievement. The highest GFA among Cu-containing alloys was found for the Zr（56） Co（22） Cu6 Al（16） alloy, which was similar to that of the base alloy. Furthermore, the plasticity of the base alloy increased significantly from 3.3% to 6% for the Zr（56） Co（22） Cu）6 Al（16） BMG. The variations in the plasticity and GFA of the alloys were discussed by considering the positive heat of mixing within Cu and Co elements.
基金Sharif University of Technology for the financial support
文摘Cu–15%NbC (volume fraction) powder was synthesized using the starting powders of Cu, Nb and graphite in a high energy vibratory disc mill for 7 h of milling under argon atmosphere. A composite sample and a Cu/NbC functionally graded material (FGM) sample were produced by using the two-step press and sintering at 900 °C for 1 h under vacuum. The microstructure and physical and mechanical properties of the specimens were investigated. The field emission scanning electron microscopy, energy dispersive X-ray and X-ray diffraction analysis confirmed the synthesis of the nanostructure matrix of 18–27 nm with the nanoparticles reinforcement of 42 nm after sintering, verifying the thermal stability of this composite at high temperature. The hardness of Cu–15%NbC was five times greater than that of the pure Cu specimen. The volume reduction of the sample after the wear test decreased in comparison with the pure Cu specimen. The electrical conductivity of the composite specimen decreased to 36.68% IACS. The FGM specimen exhibited high electrical conductivity corresponding to 75.83% IACS with the same hardness and wear properties as those of the composite sample on the composite surface. Thus, Cu/NbC FGM with good mechanical and electrical properties can be a good candidate for electrical contact applications.
基金National Natural Science Foundation of China,Grant/Award Numbers:51972121,51972270,51702262Tip-top Scientific and Technical Innovative Youth Talents of Guangdong Special Support Program,Grant/Award Number:2017TQ04C419Key Research and Development Program of Shaanxi Province,Grant/Award Number:2019TSLGY07-03。
文摘The limited lithium resource in earth's crust has stimulated the pursuit of alternative energy storage technologies to lithium-ion battery.Potassium-ion batteries(KIBs)are regarded as a kind of promising candidate for large-scale energy storage owing to the high abundance and low cost of potassium resources.Nevertheless,further development and wide application of KIBs are still challenged by several obstacles,one of which is their fast capacity deterioration at high rates.A considerable amount of effort has recently been devoted to address this problem by developing advanced carbonaceous anode materials with diverse structures and morphologies.This review presents and highlights how the architecture engineering of carbonaceous anode materials gives rise to high-rate performances for KIBs,and also the beneficial conceptions are consciously extracted from the recent progress.Particularly,basic insights into the recent engineering strategies,structural innovation,and the related advances of carbonaceous anodes for high-rate KIBs are under specific concerns.Based on the achievements attained so far,a perspective on the foregoing,and proposed possible directions,and avenues for designing high-rate anodes,are presented finally.
基金The research is supported by the National Key Research and Development Program of China(2017YFB0304504)Fund of Key Laboratory of Advanced Materials of Ministry of Education(No.XJCL201908)National Key Basic Research Program of China(2015CB654804).
文摘The contributions of different strengthening mechanisms to yield strength of bainite/martensite multiphase rail steel with different finish cooling temperatures in the controlled cooling process were quantitatively investigated.Dislocation density and substructure size of the rail steel were measured by scanning electron microscopy,electron backscatter diffraction and X-ray diffraction.The results show that the dislocation density increases with the decrease in block width in rail steel.Based on the correlation among dislocation density,block width and yield strength,a physical model was proposed to predict the yield strength of rail steel.The variation of block width and dislocation density in different positions of rail head microstructure was integrated with temperature field simulation.Dislocation density and block width reveal significant correlations with the finish cooling temperature.
基金supported by the National Key Research and Development Program of China(No.2023YFB3711702).
文摘In low-density steel,κ-carbides primarily precipitate in the form of nanoscale particles within austenite grains.However,their precipitation within ferrite matrix grains has not been comprehensively explored,and the second-phase evolution mechanism during aging remains unclear.In this study,the crystallographic characteristics and morphological evolution ofκ-carbides in Fe-28Mn-10Al-0.8C(wt%)low-density steel at different aging temperatures and times and the impacts of these changes on the steels’microhardness and properties were comprehensively analyzed.Under different heat treatment conditions,intragranularκ-carbides exhibited various morpho-logical and crystallographic characteristics,such as acicular,spherical,and short rod-like shapes.At the initial stage of aging,acicularκ-carbides primarily precipitated,accompanied by a few spherical carbides.κ-Carbides grew and coarsened with aging time,the spherical carbides were considerably reduced,and rod-like carbides coarsened.Vickers hardness testing demonstrated that the material’s hardness was affected by the volume fraction,morphology,and size ofκ-carbides.Extended aging at higher temperatures led to an increase in carbide size and volume fraction,resulting in a gradual rise in hardness.During deformation,the primary mechanisms for strengthening were dislocation strengthening and second-phase strengthening.Based on these findings,potential strategies for improving material strength are proposed.
基金supported by the National Natural Science Foundation of China(Grant Nos.51871222,52171021,and 51801214)Liaoning Provincial Natural Science Foundation(2019-MS-335)the research fund of SYNL。
文摘In-situ electron irradiation and aging are applied to introduce high-density precipitates in an Mg-10Gd-3Y-1Zn-0.5Zr(GWZ1031K,wt.%)alloy to improve the hardness.The results show that the hardness of the Mg alloy after irradiation for 10 h and aging for 9 h at 250℃ is 1.64 GPa,which is approximately 64% higher than that of the samples before being treated.It is mainly attributed to γ'precipitates on the basal plane after irradiation and the high-density nanoscale β'precipitates on the prismatic plane after aging,which should be closely related to the irradiation-induced homogenous clusters.The latter plays a key role in precipitation hardening.This result paves a way to improve the mechanical properties of metallic materials by tailoring the precipitation through irradiation and aging.
文摘The cast-decant-cast is a new method for the preparation of the functionally graded components that has been developed in recent years. The functionally graded cylindrical shape component with a radial gradient, e.g. the first alloy （A390） with high wear resistance on the surface of the piece and toughness and the second alloy （A356） of low machining costs in the core of the piece can be produced via this melt process. The effect of the second alloy superheat at temperatures of 750, 820 and 860 ℃ as well as the effect of the first alloy solidified layer at 25, 35 and 45 s decanting time on achieving the perfect interface between the two alloys was investigated. The characterization of the interface was carded out by optical microscopy and scanning electron microscopy, and its width was measured by the microhardness test. The results showed that the best interface was obtained at 860 ℃ and 35 s decanting time with a width of 500 ~tm. Also, the wear resistance test was performed to measure and compare the surface wear resistance to the core.
基金supported by the Key Project of Sichuan Education Department(16ZA0399)the Sichuan Science and Technology Program(2017JY0107)+2 种基金the Leshan Science and Technology Bureau of China(17GZD041)Science and Technology Project of Yantian District in Shenzhen City,Guangdong Province,China(20190106)the Training Programs of Innovation and Entrepreneurship for Undergraduates of Sun Yat-Sen University(20201062).
文摘Chemotherapy is still a kind of important strategy for cancer treatment,but lacking effective delivery system limits the therapeutic outcome.Owing to the excellent biocompatibility,albumin has been employed as drug vehicle;however,it has to face complicated synthesis procedures and still needs an effective technology for the drug delivery evaluation.In this study,a facile method was utilized to prepare a protein-based theranostic system through the self-assembly of albumins with small molecules and drugs;furthermore,the paramagnetic divalent manganese ions were conjugated on the surface of the nanocomposite through a coordination bond and carried out the magnetic resonance imaging.This nanosystem with a stable structure exhibited about 80 nanometer size and 7.7[Mn]mM-1S-1 T1 relaxivity;moreover,the pH-sensitive drug releasing property and the imaging function empower it with theranostic cancer therapy.Moreover,the nanocomposites effectively entered into the cancer cells and showed superior antitumor ability;and these treated cells exhibited significant T1 signal.These results suggested that the albumin-based nanosystem is a novel chemotherapy drug delivery vehicle and a promising candidate for magnetic resonance imaging.
基金National Natural Science Foundation of China,Grant/Award Numbers:21905265,52072322,U1930402,61974042National Science Foundation,Civil,Mechanical and Manufacturing Innovation,Grant/Award Number:1911905+3 种基金Fundamental Research Funds for the Central Universities,Grant/Award Number:WK2060140026Department of Science and Technology of Sichuan Province,Grant/Award Numbers:2019‐GH02‐00052‐HZ,2019YFG0220Scientific and Technological Innovation Foundation of Shunde Graduate School,Grant/Award Number:BK19BE024National Key Research and Development Program of China,Grant/Award Number:2017YFA0303403。
文摘A new concentrated ternary salt ether-based electrolyte enables stable cycling of lithium metal battery(LMB)cells with high-mass-loading(13.8 mg cm^(−2),2.5 mAh cm^(−2))NMC622(LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2))cathodes and 50μm Li anodes.Termed“CETHER-3,”this electrolyte is based on LiTFSI,LiDFOB,and LiBF4 with 5 vol%fluorinated ethylene carbonate in 1,2-dimethoxyethane.Commer-cial carbonate and state-of-the-art binary salt ether electrolytes were also tested as baselines.With CETHER-3,the electrochemical performance of the full-cell battery is among the most favorably reported in terms of high-voltage cycling stability.For example,LiNi_(x)Mn_(y)Co_(1-x-y)O_(2)(NMC)-Li metal cells retain 80%capacity at 430 cycles with a 4.4 V cut-off and 83%capacity at 100 cycles with a 4.5 V cut-off(charge at C/5,discharge at C/2).According to simulation by density functional theory and molecular dynamics,this favorable performance is an outcome of enhanced coordination between Li^(+)and the solvent/salt molecules.Combining advanced microscopy(high-resolution transmission electron microscopy,scanning electron microscopy)and surface science(X-ray photoelectron spectroscopy,time-of-fight secondary ion mass spectroscopy,Fourier-transform infrared spectroscopy,Raman spectroscopy),it is demonstrated that a thinner and more stable cathode electrolyte interphase(CEI)and solid electrolyte interphase(SEI)are formed.The CEI is rich in lithium sulfide(Li_(2)SO_(3)),while the SEI is rich in Li_(3)N and LiF.During cycling,the CEI/SEI suppresses both the deleterious transformation of the cathode R-3m layered near-surface structure into disordered rock salt and the growth of lithium metal dendrites.
文摘The dry friction and wear characteristics of rare earth/MoSi 2 composite against 45 steel under different loads were investigated by using an M 200 type friction and wear tester. SEM and XRD were used to analyze the morphology of the friction surface and the phase of worn piece in order to reveal the wear mechanism of rare earth/MoSi 2 composite. Results show that the relationships of friction coefficient, μ , or wear rate, W , of MoSi 2 and RE/MoSi 2 composite to loads, p , can be fitted well with the following function: μ (or W )= a+bp+cp 2+dp 3+ep 4 , where a, b, c, d and e are fitting constants depending on materials and confidence. MoSi 2 and rare earth/MoSi 2 composite have excellent wear resistance. When load is in the range of 80～120 N, the wear rate of RE/MoSi 2 composite is lower than that of MoSi 2 material by about 65%. The main wear mechanism of rare earth/MoSi 2 composite is adhesive wear.
文摘The dry friction and wear properties of intermetallics MoSi 2 against 45 steel under different loads were investigated with M 2 type friction and wear tester. Scanning electric microscope (SEM) equipment with microprobe was employed to analyze the morphology of the friction surface. Results show that the dry friction and wear properties are deeply affected by load. The wear rate of MoSi 2 at the load of 80?N is the maximum which is 36.1?μg/m. On the condition of the load of 150?N, MoSi 2 material has the better friction and wear properties: friction coefficient is 0.28 and wear rate is 10.6?μg/m. With the load increasing, the main friction mechanisms change from microslip and plastic deformation to adhesive effect, and the main wear mechanisms change from plough groove wear and oxidation fatigue wear to adhesive wear.
基金This work is supported by the National Natural Science Foundation of China(grant number 51801214 and 51871222)Guangxi Science and Technology Base and Talents Special Project(Guike AD20297034)+2 种基金Liaoning Provincial Natural Science Foundation(2019-MS-335)Research Start-up Funding from Guangxi University of Science and Technology(No.03200150)Natural Science Foundation of Hebei Province of China(grant number E2020208083).
文摘The role of melt cooling rate on the interface morphology and dislocation configuration between 18R long-period stacking ordered(LPSO)structure and Mg matrix in Mg_(97)Zn_(1)Y_(2)(at.%)alloys was investigated by atomic-scale HAADF-STEM imaging.The 18R/Mg interface is step-like both in the near-equilibrium alloy and non-equilibrium alloy.Lower cooling rate makes the step size more regular and larger.Only 54R structure can be observed at the interface in the near-equilibrium alloy,and the dislocations are highly ordered.54R and 54R′structure sandwiched by b1 and b2+b3 dislocation arrays,and new dislocation configuration can be detected at the interface in the non-equilibrium alloy,but the dislocations are less ordered.18R/Mg interface containing 54R or 54R′in equilibrium width,parallel to the(010)plane,should be most stable based on elastic calculation.The segregation of solute atoms and its strong interaction with dislocations dominate the LPSO/Mg interface via diffusion-displacive transformation.
基金the Programa de Cooperación Territorial INTERREG V-A MAC 2014-2020 and Inv2Mac Project(MAC/4.6d/229)the partial support of FCT-Funda??o para a Ciência e a Tecnologia(Base Fund UIDB/00674/2020)+1 种基金ARDITI-Agência Regional para o Desenvolvimento da Investiga??o Tecnologia e Inova??o supported the study through the project M1420-01-0145FEDER-000005-CQM+(Madeira 14-20 Program)the Postdoc Grant(M1420-09-5369-FSE-000001,002458/2015/132)for Carla S.ALVES is also acknowledged。
文摘In this study,the fibers of invasive species Agave americana L.and Ricinus communis L.were successfully used for the first time as new sources to produce cytocompatible and highly crystalline cellulose nanofibers.Cellulose nanofibers were obtained by two methods,based on either alkaline or acid hydrolysis.The morphology,chemical composition,and crystallinity of the obtained materials were characterized by scanning electron microscopy(SEM)together with energy-dispersive X-ray spectroscopy(EDX),dynamic light scattering(DLS),X-ray diffraction(XRD),and Fourier transform infrared(FTIR)spectroscopy.The crystallinity indexes(CIs)of the cellulose nanofibers extracted from A.americana and R.communis were very high(94.1%and 92.7%,respectively).Biological studies evaluating the cytotoxic effects of the prepared cellulose nanofibers on human embryonic kidney 293 T(HEK293 T)cells were also performed.The nanofibers obtained using the two different extraction methods were all shown to be cytocompatible in the concentration range assayed(i.e.,0-500μg/mL).Our results showed that the nanocellulose extracted from A.americana and R.communis fibers has high potential as a new renewable green source of highly crystalline cellulose-based cytocompatible nanomaterials for biomedical applications.
基金financially supported by the China Postdoctoral Science Foundation(No.2015M570964)the National Key Research and Development Program of China(No.2017YFB0304504)。
文摘Nanoporous Ag-Pt bi-metallic alloy was fabricated by free dealloying of amorphous Ag-based precursor with the nominal composition of Ag38.25Pt0.5Cu38.75Si22.5.The noble Ag and Pt were left after the less noble Cu and Si dissolved in a certain acid solution.Bi-continuous nanoporous microstructure was formed with asymmetric ligaments and pores with typically 30-200 nm in width.The trace addition of Pt has refined the grains of the ligaments to the average size of less than 20 nm in the substrate and induced the formation of rods with nanopores.The morphologies of the rods were observed by scanning electron microscopy(SEM)and transmission electron microscopy(TEM)both in the form of clusters and as scattered individuals with characteristic length of several micrometers and diameter of tens of nanometers.The grains sizes in the rods were finer than those in the ligaments.The good mechanical integrity might be due to the combination of continuous ligaments and clusters of rods.
文摘The impregnation of nanoparticles magnetified into wood had been developed by different methods,like surface chemical coprecipitation and vacuum-pressure coprecipitation of magnetic nanoparticles(NPs).However,there is a lack of information on the best method to coprecipitation NPs.Then,the present study has the objective to measure the effects of the impregnation process of wood veneers through two in situ processes(immersion and vacuum-pressure)using a solution of FeCl_(3)·6H_(2)O,FeCl_(2)·4H_(2)O and ammonia in three tropical species(Pinus oocarpa,Vochysia ferruginea and Vochysia guatemalensis).It was measured the degree of synthesis of iron NPs using weight and density gains,Fe^(3+) absorption,emission scanning electron microscope(SEM),Fournier transform infrared spectroscopy(FT-IR)and for magnetic properties were measured using vibrating sample magnetometry(VSM).After 5-layer veneer panels were fabricated,we evaluated their physical and mechanical properties.Wood samples impregnated by vacuum-pressure methods showed the higher amount of Fe_(3)O_(4)NPs formation,which was observed in the SEM,X-ray diffraction(XDR),FT-IR and VSM.Vacuum-pressure on treatment presented higher ferrite signals and better magnetic properties.Vochysia ferruginea presented the greatest magnetization properties.The magnetization treated causes probably a degradation of the cell wall,which weakens its mechanical properties,especially internal bonding.
