Knee osteoarthritis （OA） is the most common form of arthritis worldwide. The incidence of this disease is rising and its treatment poses an economic burden. Two early targets of knee OA treatment include the predomi...Knee osteoarthritis （OA） is the most common form of arthritis worldwide. The incidence of this disease is rising and its treatment poses an economic burden. Two early targets of knee OA treatment include the predominant symptom of pain, and cartilage damage in the knee joint. Current treatments have been beneficial in treating the disease but none is as effective as total knee arthroplasty （TKA）. However, while TKA is an end-stage solution of the disease, it is an invasive and expensive procedure, Therefore, innovative regenerative engineering strategies should be established as these could defer or annul the need for a TKA. Several biomaterial and cell-based therapies are currently in development and have shown early promise in both preclinical and clinical studies. The use of advanced biomaterials and stem cells independently or in conjunction to treat knee OA could potentially reduce pain and regenerate fo- cal articular cartilage damage. In this review, we discuss the pathogenesis of pain and cartilage damage in knee OA and explore novel treatment options currently being studied, along with some of their limitations.展开更多
High pressure die casting(HPDC)AlSi10Mn Mg alloy castings are widely used in the automobile industry.Mg can optimize the mechanical properties of castings through heat treatment,while the release of thermal stress aro...High pressure die casting(HPDC)AlSi10Mn Mg alloy castings are widely used in the automobile industry.Mg can optimize the mechanical properties of castings through heat treatment,while the release of thermal stress arouses the deformation of large integrated die-castings.Herein,the development of non-heat treatment Al alloys is becoming the hot topic.In addition,HPDC contains externally solidified crystals(ESCs),which are detrimental to the mechanical properties of castings.To achieve high strength and toughness of non-heat treatment die-casting Al-Si alloy,we used AlSi9Mn alloy as matrix with the introduction of Zr,Ti,Nb,and Ce.Their influences on ESCs and mechanical properties were systematically investigated through three-dimensional reconstruction and thermodynamic simulation.Our results reveal that the addition of Ti increased ESCs'size and porosity,while the introduction of Nb refined ESCs and decreased porosity.Meanwhile,large-sized Al_3(Zr,Ti)phases formed and degraded the mechanical properties.Subsequent introduction of Ce resulted in the poisoning effect and reduced mechanical properties.展开更多
By method of TIG,two kinds of welding materials were filled in and under certain welding craft conditions,1Cr18Ni9Ti and 2Cr13 were welded.The microstructure of two kinds of welded joints were observed and analyzed by...By method of TIG,two kinds of welding materials were filled in and under certain welding craft conditions,1Cr18Ni9Ti and 2Cr13 were welded.The microstructure of two kinds of welded joints were observed and analyzed by OM,SEM.Through seawater immersion test,polarization curves and AC impedance spectroscopy of two kinds of welding joints were obtained.The results show that 2Cr13 and 1Cr18Ni9Ti welded joints are typical columnar crystal,the microstructure is lath martensite+austenite+carbide.The welded joints that filled in 308 and H1Cr21Ni10Mn7Mo welding wires,corrosion resistance has same change rule:Austenite base metal>HAZ near Austenite>welded joint>HAZ near Martensite>Martensite base metal.The every zone contrast of two kinds of welded joint corrosion resistance obtains:the welded joints filled in 308>the welded joints filled in H1Cr21Ni10Mn7Mo.展开更多
The precursors of La0.7Sr0.3-xCaxCo0.9Fe0.1O3-δ(LSCCF, x=0.05, 0.10, 0.15, 0.20) as the cathode materials for intermediate temperature solid oxide fuel cell (ITSOFC) were prepared by reverse titration co-precipitatio...The precursors of La0.7Sr0.3-xCaxCo0.9Fe0.1O3-δ(LSCCF, x=0.05, 0.10, 0.15, 0.20) as the cathode materials for intermediate temperature solid oxide fuel cell (ITSOFC) were prepared by reverse titration co-precipitation method with metal-nitrates as starting materials and mixed alkali (NaOH and Na2CO3) as a precipitating agent. The formation process of LSCCF from the precursors was monitored by TG-DSC, and the crystal structure and particles morphology of the precursors which were calcined at 600, 800, 1000 ℃ for 3 h were characterized using XRD, SEM technologies. Compared with the solid state reaction of constituent oxides, when the pH value of the precipitating solution was in the range of 9.1～9.5, the LSCCF powders from the precursors caclined at 800 ℃ for 3 h had high purity, homogeneous and single perovskite phase. The electrical conductivity of the LSCCF samples sintered at 1200 ℃ for 3 h, which was measured as a function of temperatures from 100 to 800 ℃ by DC four-probe method in air, decreased with x from 0.05 to 0.20. The value of electrical conductivity was almost equal because of Ca2+, Sr2+ co-dopant resulting in the 'mix effect' while x=0.10 or 0.15. The electrical conductivity of all doped samples was higher than 100 S·cm-1 at intermediate temperatures from 500 to 800 ℃, and there was good compatibility between the LSCCF cathode and Ce0.8Sm0.2O2 electrolyte.展开更多
AlSiCp （65 vol.% SiC） electronic packaging materials were manufactured by powder injection molding （PIM） and pressure infiltration process in order to obtain near net-shaped parts. SiCp preformed compacts obtained...AlSiCp （65 vol.% SiC） electronic packaging materials were manufactured by powder injection molding （PIM） and pressure infiltration process in order to obtain near net-shaped parts. SiCp preformed compacts obtained by pre-sintering process at 1150 K have high strength and good appearance, and the ratio of open porosity to total porosity is nearly 98%. The relative density of composites is bigger than 99%. The thermal conductivity of A1SiCp composites fabricated by this method is 198 W·m^-1·K^-1, and the coefficient of thermal expansion （CTE） is 8.0 × 10^-6/K （298 K）.展开更多
Despite the existence of conventional methods for recycling chips,solid-state techniques have become popular,whereby waste metals are directly recycled into consolidated products with the desired shapes and designs.We...Despite the existence of conventional methods for recycling chips,solid-state techniques have become popular,whereby waste metals are directly recycled into consolidated products with the desired shapes and designs.We investigated the feasibility of recycling phosphor bronze chips through a hot extrusion process using aluminum powder as a metal binder for the fabrication of a metal-fiber-reinforced aluminum matrix composite.To do so,mixtures containing 20 vol%–50 vol%of chips were prepared,cold-compacted,and extruded.The quality of the consolidated samples was evaluated by determining the density of the fabricated composites and studying their microstructures.In addition,we performed tensile and hardness tests to evaluate the mechanical properties of the fabricated composites.We also analyzed the fracture surfaces of the samples to study the fracture mechanism as a function of the volume fraction of phosphor bronze chips in the fabricated composite.The results indicated that the most effective consolidation occurred in the sample containing 20 vol%of chips extruded at 465℃in which the chips serve as ideal fibers for improving the mechanical properties,especially the ultimate tensile strength,in comparison with those of Al matrixes that contain no chips but are produced under the same conditions.展开更多
Enhancing both the number of active sites available and the intrinsic activity of Co-based electrocatalysts simultaneously is a desirable goal.Herein,a ZIF-67-derived hierarchical porous cobalt sulfide decorated by Au...Enhancing both the number of active sites available and the intrinsic activity of Co-based electrocatalysts simultaneously is a desirable goal.Herein,a ZIF-67-derived hierarchical porous cobalt sulfide decorated by Au nanoparticles(NPs)(denoted as HP-Au@CoxSy@ZIF-67)hybrid is synthesized by low-temperature sulfuration treatment.The well-defined macroporous-mesoporous-microporous structure is obtained based on the combination of polystyrene spheres,as-formed CoxSy nanosheets,and ZIF-67 frameworks.This novel three-dimensional hierarchical structure significantly enlarges the three-phase interfaces,accelerating the mass transfer and exposing the active centers for oxygen evolution reaction.The electronic structure of Co is modulated by Au through charge transfer,and a series of experiments,together with theoretical analysis,is performed to ascertain the electronic modulation of Co by Au.Meanwhile,HP-Au@CoxSy@ZIF-67 catalysts with different amounts of Au were synthesized,wherein Au and NaBH4 reductant result in an interesting“competition effect”to regulate the relative ratio of Co^(2+)/Co^(3+),and moderate Au assists the electrochemical performance to reach the highest value.Consequently,the optimized HP-Au@CoxSy@ZIF-67 exhibits a low overpotential of 340 mV at 10 mA cm^(-2)and a Tafel slope of 42 mV dec-1 for OER in 0.1 M aqueous KOH,enabling efficient water splitting and Zn-air battery performance.The work here highlights the pivotal roles of both microstructural and electronic modulation in enhancing electrocatalytic activity and presents a feasible strategy for designing and optimizing advanced electrocatalysts.展开更多
Cadmium sulfide(CdS)is an n-type semiconductor with excellent electrical conductivity that is widely used as an electron transport material(ETM)in solar cells.At present,numerous methods for preparing CdS thin films h...Cadmium sulfide(CdS)is an n-type semiconductor with excellent electrical conductivity that is widely used as an electron transport material(ETM)in solar cells.At present,numerous methods for preparing CdS thin films have emerged,among which magnetron sputtering(MS)is one of the most commonly used vacuum techniques.For this type of technique,the substrate temperature is one of the key deposition parameters that affects the interfacial properties between the target film and substrate,determining the specific growth habits of the films.Herein,the effect of substrate temperature on the microstructure and electrical properties of magnetron-sputtered CdS(MS-CdS)films was studied and applied for the first time in hydrothermally deposited antimony selenosulfide(Sb_(2)(S,Se)_(3))solar cells.Adjusting the substrate temperature not only results in the design of the flat and dense film with enhanced crystallinity but also leads to the formation of an energy level arrangement with a Sb_(2)(S,Se)_(3)layer that is more favorable for electron transfer.In addition,we developed an oxygen plasma treatment for CdS,reducing the parasitic absorption of the device and resulting in an increase in the short-circuit current density of the solar cell.This study demonstrates the feasibility of MS-CdS in the fabrication of hydrothermal Sb_(2)(S,Se)_(3)solar cells and provides interface optimization strategies to improve device performance.展开更多
Compared to the commercial soft-magnetic alloys,the high saturation magnetic flux density(Bs)and low coercivity(Hc)of post-developed novel nanocrystalline alloys tend to realize the miniaturization and lightweight of ...Compared to the commercial soft-magnetic alloys,the high saturation magnetic flux density(Bs)and low coercivity(Hc)of post-developed novel nanocrystalline alloys tend to realize the miniaturization and lightweight of electronic products,thus attracting great attention.In this work,we designed a new FeNiBCuSi formulation with a novel atomic ratio,and the microstructure evolution and magnetic softness were investigated.Microstructure analysis revealed that the amount of Si prompted the differential chemical fluctuations of Cu element,favoring the different nucleation and growth processes ofα-Fe nanocrystals.Furthermore,microstructural defects associated with chemical heterogeneities were unveiled using the Maxwell-Voigt model with two Kelvin units and one Maxwell unit based on creeping analysis by nanoindentation.The defect,with a long relaxation time in relaxation spectra,was more likely to induce the formation of crystal nuclei that ultimately evolved into theα-Fe nanocrystals.As a result,Fe_(84)Ni_(2)B_(12.5)Cu_(1)Si_(0.5)alloy with refined uniform nanocrystalline microstructure exhibited excellent magnetic softness,including a high B_(s)of 1.79 T and very low H_(c)of 2.8 A/m.Our finding offers new insight into the influence of activated defects associated with chemical heterogeneities on the microstructures of nanocrystalline alloy with excellent magnetic softness.展开更多
To investigate the influences of Cr_(2)AlC mass fraction and supersonic plasma spraying process on the microstructure and mechanical properties of Cr_(2)AlC reinforced 410 stainless steel composite coatings,the coatin...To investigate the influences of Cr_(2)AlC mass fraction and supersonic plasma spraying process on the microstructure and mechanical properties of Cr_(2)AlC reinforced 410 stainless steel composite coatings,the coatings containing different mass fractions of Cr_(2)AlC were prepared and investigated.The composite coating exhibited low porosity and high adhesion strength.The addition of Cr_(2)AlC significantly enhanced the hardness of the composite coatings through particle strengthening.However,when the mass fraction of Cr_(2)AlC was 20%,the aggregation of Cr_(2)AlC resulted in a strong decrease in the coating preparation efficiency,as well as a decline in adhesion strength.In the supersonic plasma spraying process,the Ar flow rate mainly influenced the flight velocity of the particles,while the H_(2) flow rate and the current mainly affected the temperature of the plasma torch.Consequently,all of them influenced the melting degree of particles and the quality of the coating.The lowest porosity and the highest hardness and adhesion strength could be obtained when the Ar flow rate is 125 L/min,the H_(2) flow rate is 25 L/min,and the current is 385 A.展开更多
This research investigates the potential of blending complementary lard oil with rubber seed oil as feedstock for biodiesel production.Rubber seed oil,obtained through hexane extraction using the Soxhlet method,contai...This research investigates the potential of blending complementary lard oil with rubber seed oil as feedstock for biodiesel production.Rubber seed oil,obtained through hexane extraction using the Soxhlet method,contains the major fatty acids of oleic acid(C_(18:1)),palmitic acid(C_(16:0)),linoleic acid(C_(18:2)),and stearic acid(C_(18:0)),while rubber seed oil primarily consists of linoleic acid(C_(18:2)),oleic acid(C_(18:1)),linolenic acid(C_(18:3)),palmitic acid(C_(16:0)),and stearic acid(C_(18:0)).The least acid value of lard oil(0.55 mg KOH/g)can benefit of reducing soap formation of rubber seed oil during transesterification process in biodiesel production due to its substantial-high acid value(16.28 mg KOH/g).Blending at ratios below 80:20 volume ratio produced biodiesel exceeding 85%,utilizing CaO as a catalyst.Lard oil demonstrated a higher reaction rate constant(11.88×10^(-3)min^(-1))than rubber seed oil(2.11×10^(-3)min^(-1)),indicating a significant difference in performance.High acid value and free fatty acids in rubber seed oil correlated with lower reaction rates.Maintaining a mixture ratio below 80:20 volume ratio optimized reaction rates during biodiesel production.Biodiesel obtained from blends below 80:20 volume ratio met ASTM D6751 and EN 14214 standards,demonstrating suitability for bio-auto fuel.The drawbacks of using rubber seed oil as a raw material for biodiesel production are overcome by blending with lard oil,giving rise to expanding renewable energy options for rural communities,community enterprises,and large-scale biodiesel production.展开更多
All-solid-state sodium(Na)-metal batteries(ASSSMBs)are considered promising candidates for large-scale energy storage systems due to their abundant sodium resources,unparalleled safety performance,and impressive energ...All-solid-state sodium(Na)-metal batteries(ASSSMBs)are considered promising candidates for large-scale energy storage systems due to their abundant sodium resources,unparalleled safety performance,and impressive energy density.Na superionic conductors(NASICONs)are among the best enablers of ASSSMBs in view of their high ionic conductivity,ease of synthesis,and excellent thermal stability and good electrochemical/chemical compatibility with common electrodes.However,challenges surrounding the NASICON/electrode interface,such as high interfacial resistance and dendrite formation,have hindered the development of practical ASSSMBs based on NASICONs.This review starts with an explicit summary of the interface problems between the metallic Na anode and NASICON arising from mechanical,chemical,and electrochemical aspects(i.e.,poor interface contact,insulating side-reaction products,and irregular dendrite growth).Subsequently,we systematically analyze and logically categorize modification strategies for addressing anode interface problems and provide a comprehensive discussion on the underlying enhancement mechanisms.As such,we identify underlying and universal interface enhancement mechanisms by comparatively studying various modification strategies.Furthermore,we briefly summarize the challenges in the cathode/electrolyte interface and early-stage research efforts in constructing stable cathode/electrolyte interface and fabricating high-performance composite cathodes.Finally,key suggestions and future prospectives for the advancement of NASICON-based ASSSMBs are outlined.展开更多
The corrosion resistance of 2024-T3 aluminum alloy was improved by anodizing treatment in a mixed electrolyte containing 10% sulfuric acid, 5% boric acid and 2% phosphoric acid. Electrochemical impedance spectroscopy ...The corrosion resistance of 2024-T3 aluminum alloy was improved by anodizing treatment in a mixed electrolyte containing 10% sulfuric acid, 5% boric acid and 2% phosphoric acid. Electrochemical impedance spectroscopy （EIS） technique was used to study the corrosion behavior of the anodized alloy. Using Tafel plot and salt spray techniques, it is revealed that the anodizing treatment of 2024-T3 aluminum alloy in sulfuric-boric-phosphoric acids provides better corrosion resistance and durability in comparison with the anodizing treatment in phosphoric acid or sulfuric-boric acids. This electrolyte can be a suitable alternative for chromate baths which are generally used in the anodizing of aluminum alloys.展开更多
The semi-solid slurry of a hypoeutectic Al-Si alloy was manufactured by low superheat pouring and weak electromagnetic stirring. The effects of pouting temperature and stirring power on the semi-solid slurry were inve...The semi-solid slurry of a hypoeutectic Al-Si alloy was manufactured by low superheat pouring and weak electromagnetic stirring. The effects of pouting temperature and stirring power on the semi-solid slurry were investigated. The results indicated that the semi-solid slurry to satisfy rheocasting can be manufactured by low superheat pouring and weak electromagnetic stirring. The pouring temperature （or superheat） and the stirring power remarkably affected the morphology of primary α-Al and the size of primary α-Al, and there is no obvious effect of stirring time on primary α-Al. Compared with the samples made by low superheat pouring with no stirring, the nucleation rate, particle morphology and grain size of primary α-Al in A356 were markedly improved by low superheat pouring and weak electromagnetic stirring. On the condition of weak electromagnetic stirring, the pouring temperature with low superheat can be suitably raised to reach the effectiveness obtained from the lower pouring temperature without stirring.展开更多
The effects of the deformation in the non-recrystallization region of austenite and the cooling rate on the transformation behavior and microstructure of low-carbon low-alloy steel for pipeline application were studie...The effects of the deformation in the non-recrystallization region of austenite and the cooling rate on the transformation behavior and microstructure of low-carbon low-alloy steel for pipeline application were studied on the thermal-mechanical simulator Gleeble-1500. It was shown that an increase in deformation amount can greatly increase the nucleation site of ferrite when deformed in the non-recrystallization region of austenite, and an increase in nucleation ratio can greatly refine grains. When the cooling rate is accelerated, the driving force of nucleation is increased and the nucleation rate also improves. Ultra-refine grains can be obtained by controlled rolling. The high density of ferrite nucleus, which forms along the austenite grain boundary, twin interface, and deformation band are introduced in the matrix of austenite by the control of hot rolling, after which the microstructure can be refined. It was found that the acicular ferrite has a very fine sub-structure, high dislocation density, and a thin slab with ultra-fine grains. Small M/A islands and cementite are precipitated on the matrix of the slabs by the analysis technique of TEM and SEM.展开更多
The magnesium alloy is prone to burn during die-casting, which limits its applications severely, so the effect of adding rare earth （RE） on the ignition-proof of AZ91D Mg alloy is studied. The results indicate that ...The magnesium alloy is prone to burn during die-casting, which limits its applications severely, so the effect of adding rare earth （RE） on the ignition-proof of AZ91D Mg alloy is studied. The results indicate that the addition of mischmetal RE elements has a remarkable influence on the ignition-proof property of the magnesium alloy. It is found that the ignition temperature of the magnesium alloy can be greatly raised by adding a proper amount of RE. When the amount is 0.1wt%, the ignition temperature reaches 877℃ which is 206℃ higher than that of AZ91D without RE and the mechanical properties of the alloy are also improved, However, the amount of RE must be properly controlled because too much RE would induce grain coarsening and reduce the mechanical properties.展开更多
The kinetics of isothermal reduction of Ag2O with graphite under argon atmosphere for a non-activated sample and mechanically activated sample was investigated.It is found that Johnson-Mehl-Avrami model appropriately ...The kinetics of isothermal reduction of Ag2O with graphite under argon atmosphere for a non-activated sample and mechanically activated sample was investigated.It is found that Johnson-Mehl-Avrami model appropriately explained the thermal and mechanochemical synthesis of Ag from Ag2O＋ghraphite mixture.The process kinetics was investigated using the same approach for milled and unmilled samples.The results show that the Avrami exponent of mechanochemical reduction is higher than that of high temperature thermal reduction.Also,the mechanisms of nuclei growth in thermal and mechanochemical reduction are diffusion controlled and interface controlled,respectively.展开更多
The advancement in the materials manufacturing at micrometer and nanometer scales has already enabled numerous applications in electronics, optics, chemistry, biology and medicine. Biomedical devices carrying micro-/n...The advancement in the materials manufacturing at micrometer and nanometer scales has already enabled numerous applications in electronics, optics, chemistry, biology and medicine. Biomedical devices carrying micro-/nanostructures are currently being widely used in drug delivery, drug release, biosensing and therapy. New clinical methods for disease diagnosis and treatments are being developed enabled by nanotech no logy. One-dimensional (ID) structures are playi ng an importa nt role in the direct drug delivery both in vivo and ex vivo among various micro-/nanostructures. Here, in this paper, we reviewed recent progresses made on next-generation intradermal and intracellular delivery strategies and applications with focus on ID microstructure-based approaches.展开更多
The microstructure, mechanical properties, and misorientation of automobile beam steels produced by EAF-CSP process were studied using optical microscopy （OM） and electron back-scattered diffraction （EBSD）. It is ...The microstructure, mechanical properties, and misorientation of automobile beam steels produced by EAF-CSP process were studied using optical microscopy （OM） and electron back-scattered diffraction （EBSD）. It is shown that the microstructure of strips is mainly polygonal ferrite, and the average grain size is about 5-8 μm. The electron back-scattered diffraction results show that grain boundaries in ferrite are basically high-angle grain boundaries without remarkable preferred orientation. Hot strips of automobile beam steels possess a good combination of strength and plasticity because of their fine microstructures and low quantity of impurities.展开更多
The cermet composites WC-20wt%Co/ZrO2（E6）with four different comtents of ZrO2（3Y）were prepared by normal vacuum sinter processing;the optical microscope and SEMwere used to characterize their microstructures.The h...The cermet composites WC-20wt%Co/ZrO2（E6）with four different comtents of ZrO2（3Y）were prepared by normal vacuum sinter processing;the optical microscope and SEMwere used to characterize their microstructures.The hardness.bending strength and impact toughness of the specimens were determined.The experimental results show that ZrO2（3Y） particles in WC-20wt%Co matrix are sphcrical particles in different sizes which are distributed uniformly in Co phases and WC phases,the bending strength and impact toughness of the WC-20wt%Co cermet composites added ZrO2（3Y）improve remarkably.but the hardness values have little change.展开更多
文摘Knee osteoarthritis （OA） is the most common form of arthritis worldwide. The incidence of this disease is rising and its treatment poses an economic burden. Two early targets of knee OA treatment include the predominant symptom of pain, and cartilage damage in the knee joint. Current treatments have been beneficial in treating the disease but none is as effective as total knee arthroplasty （TKA）. However, while TKA is an end-stage solution of the disease, it is an invasive and expensive procedure, Therefore, innovative regenerative engineering strategies should be established as these could defer or annul the need for a TKA. Several biomaterial and cell-based therapies are currently in development and have shown early promise in both preclinical and clinical studies. The use of advanced biomaterials and stem cells independently or in conjunction to treat knee OA could potentially reduce pain and regenerate fo- cal articular cartilage damage. In this review, we discuss the pathogenesis of pain and cartilage damage in knee OA and explore novel treatment options currently being studied, along with some of their limitations.
基金financially supported by the National Natural Science Foundation of China(Nos.52175284 and 52474396)the National Key Research and Development Program of China(No.2022YFB3404201)。
文摘High pressure die casting(HPDC)AlSi10Mn Mg alloy castings are widely used in the automobile industry.Mg can optimize the mechanical properties of castings through heat treatment,while the release of thermal stress arouses the deformation of large integrated die-castings.Herein,the development of non-heat treatment Al alloys is becoming the hot topic.In addition,HPDC contains externally solidified crystals(ESCs),which are detrimental to the mechanical properties of castings.To achieve high strength and toughness of non-heat treatment die-casting Al-Si alloy,we used AlSi9Mn alloy as matrix with the introduction of Zr,Ti,Nb,and Ce.Their influences on ESCs and mechanical properties were systematically investigated through three-dimensional reconstruction and thermodynamic simulation.Our results reveal that the addition of Ti increased ESCs'size and porosity,while the introduction of Nb refined ESCs and decreased porosity.Meanwhile,large-sized Al_3(Zr,Ti)phases formed and degraded the mechanical properties.Subsequent introduction of Ce resulted in the poisoning effect and reduced mechanical properties.
基金supported by the Anhui Provincial Natural Science Foundation(Grant No.2008085 QE 231).
文摘By method of TIG,two kinds of welding materials were filled in and under certain welding craft conditions,1Cr18Ni9Ti and 2Cr13 were welded.The microstructure of two kinds of welded joints were observed and analyzed by OM,SEM.Through seawater immersion test,polarization curves and AC impedance spectroscopy of two kinds of welding joints were obtained.The results show that 2Cr13 and 1Cr18Ni9Ti welded joints are typical columnar crystal,the microstructure is lath martensite+austenite+carbide.The welded joints that filled in 308 and H1Cr21Ni10Mn7Mo welding wires,corrosion resistance has same change rule:Austenite base metal>HAZ near Austenite>welded joint>HAZ near Martensite>Martensite base metal.The every zone contrast of two kinds of welded joint corrosion resistance obtains:the welded joints filled in 308>the welded joints filled in H1Cr21Ni10Mn7Mo.
基金the National High-Tech Development Plan (2006AA05Z417)the Natural Science Foundation of Lia-oning Province (20062145)the Education department of Liaoning Province (05L073)
文摘The precursors of La0.7Sr0.3-xCaxCo0.9Fe0.1O3-δ(LSCCF, x=0.05, 0.10, 0.15, 0.20) as the cathode materials for intermediate temperature solid oxide fuel cell (ITSOFC) were prepared by reverse titration co-precipitation method with metal-nitrates as starting materials and mixed alkali (NaOH and Na2CO3) as a precipitating agent. The formation process of LSCCF from the precursors was monitored by TG-DSC, and the crystal structure and particles morphology of the precursors which were calcined at 600, 800, 1000 ℃ for 3 h were characterized using XRD, SEM technologies. Compared with the solid state reaction of constituent oxides, when the pH value of the precipitating solution was in the range of 9.1～9.5, the LSCCF powders from the precursors caclined at 800 ℃ for 3 h had high purity, homogeneous and single perovskite phase. The electrical conductivity of the LSCCF samples sintered at 1200 ℃ for 3 h, which was measured as a function of temperatures from 100 to 800 ℃ by DC four-probe method in air, decreased with x from 0.05 to 0.20. The value of electrical conductivity was almost equal because of Ca2+, Sr2+ co-dopant resulting in the 'mix effect' while x=0.10 or 0.15. The electrical conductivity of all doped samples was higher than 100 S·cm-1 at intermediate temperatures from 500 to 800 ℃, and there was good compatibility between the LSCCF cathode and Ce0.8Sm0.2O2 electrolyte.
基金the National Natural Science Foundation of China (No. 50274014).
文摘AlSiCp （65 vol.% SiC） electronic packaging materials were manufactured by powder injection molding （PIM） and pressure infiltration process in order to obtain near net-shaped parts. SiCp preformed compacts obtained by pre-sintering process at 1150 K have high strength and good appearance, and the ratio of open porosity to total porosity is nearly 98%. The relative density of composites is bigger than 99%. The thermal conductivity of A1SiCp composites fabricated by this method is 198 W·m^-1·K^-1, and the coefficient of thermal expansion （CTE） is 8.0 × 10^-6/K （298 K）.
基金Shiraz University through grant number 97-GR-ENG-16。
文摘Despite the existence of conventional methods for recycling chips,solid-state techniques have become popular,whereby waste metals are directly recycled into consolidated products with the desired shapes and designs.We investigated the feasibility of recycling phosphor bronze chips through a hot extrusion process using aluminum powder as a metal binder for the fabrication of a metal-fiber-reinforced aluminum matrix composite.To do so,mixtures containing 20 vol%–50 vol%of chips were prepared,cold-compacted,and extruded.The quality of the consolidated samples was evaluated by determining the density of the fabricated composites and studying their microstructures.In addition,we performed tensile and hardness tests to evaluate the mechanical properties of the fabricated composites.We also analyzed the fracture surfaces of the samples to study the fracture mechanism as a function of the volume fraction of phosphor bronze chips in the fabricated composite.The results indicated that the most effective consolidation occurred in the sample containing 20 vol%of chips extruded at 465℃in which the chips serve as ideal fibers for improving the mechanical properties,especially the ultimate tensile strength,in comparison with those of Al matrixes that contain no chips but are produced under the same conditions.
基金National Natural Science Foundation of China,Grant/Award Numbers:52102260,52171211,51972220,61903235,U22A20145Shandong Provincial Natural Science Foundation,Grant/Award Numbers:ZR2020QB069,ZR2022ME051+4 种基金National Key Research and Development Program of China,Grant/Award Number:2022YFB4002004Scientific and Technological Innovation Ability Improvement Project of Minor Enterprises in Shandong Province,Grant/Award Number:2022TSGC1021Announce the List and Take Charge Project in Jinan,Grant/Award Number:202214012Major innovation project for integrating science,education and industry of Qilu University of Technology (Shandong Academy of Sciences),Grant/Award Numbers:2022JBZ01-07,2022PY044China Postdoctoral Science Foundation,Grant/Award Number:2022M711545。
文摘Enhancing both the number of active sites available and the intrinsic activity of Co-based electrocatalysts simultaneously is a desirable goal.Herein,a ZIF-67-derived hierarchical porous cobalt sulfide decorated by Au nanoparticles(NPs)(denoted as HP-Au@CoxSy@ZIF-67)hybrid is synthesized by low-temperature sulfuration treatment.The well-defined macroporous-mesoporous-microporous structure is obtained based on the combination of polystyrene spheres,as-formed CoxSy nanosheets,and ZIF-67 frameworks.This novel three-dimensional hierarchical structure significantly enlarges the three-phase interfaces,accelerating the mass transfer and exposing the active centers for oxygen evolution reaction.The electronic structure of Co is modulated by Au through charge transfer,and a series of experiments,together with theoretical analysis,is performed to ascertain the electronic modulation of Co by Au.Meanwhile,HP-Au@CoxSy@ZIF-67 catalysts with different amounts of Au were synthesized,wherein Au and NaBH4 reductant result in an interesting“competition effect”to regulate the relative ratio of Co^(2+)/Co^(3+),and moderate Au assists the electrochemical performance to reach the highest value.Consequently,the optimized HP-Au@CoxSy@ZIF-67 exhibits a low overpotential of 340 mV at 10 mA cm^(-2)and a Tafel slope of 42 mV dec-1 for OER in 0.1 M aqueous KOH,enabling efficient water splitting and Zn-air battery performance.The work here highlights the pivotal roles of both microstructural and electronic modulation in enhancing electrocatalytic activity and presents a feasible strategy for designing and optimizing advanced electrocatalysts.
基金supported by the National Natural Science Foundation of China(22275180)the National Key Research and Development Program of China(2019YFA0405600)the Collaborative Innovation Program of Hefei Science Center,CAS,and the University Synergy Innovation Program of Anhui Province(GXXT-2023-031).
文摘Cadmium sulfide(CdS)is an n-type semiconductor with excellent electrical conductivity that is widely used as an electron transport material(ETM)in solar cells.At present,numerous methods for preparing CdS thin films have emerged,among which magnetron sputtering(MS)is one of the most commonly used vacuum techniques.For this type of technique,the substrate temperature is one of the key deposition parameters that affects the interfacial properties between the target film and substrate,determining the specific growth habits of the films.Herein,the effect of substrate temperature on the microstructure and electrical properties of magnetron-sputtered CdS(MS-CdS)films was studied and applied for the first time in hydrothermally deposited antimony selenosulfide(Sb_(2)(S,Se)_(3))solar cells.Adjusting the substrate temperature not only results in the design of the flat and dense film with enhanced crystallinity but also leads to the formation of an energy level arrangement with a Sb_(2)(S,Se)_(3)layer that is more favorable for electron transfer.In addition,we developed an oxygen plasma treatment for CdS,reducing the parasitic absorption of the device and resulting in an increase in the short-circuit current density of the solar cell.This study demonstrates the feasibility of MS-CdS in the fabrication of hydrothermal Sb_(2)(S,Se)_(3)solar cells and provides interface optimization strategies to improve device performance.
基金Project supported by the Anhui Provincial Natural Science Foundation(Grant No.2208085QE121)the Key Research&Development Plan of Anhui Province(Grant No.2022a05020016)+1 种基金the University Natural Science Research Project of Anhui Province(Grant No.2023AH051084)the National Natural Science Foundation of China(Grant No.52071078)。
文摘Compared to the commercial soft-magnetic alloys,the high saturation magnetic flux density(Bs)and low coercivity(Hc)of post-developed novel nanocrystalline alloys tend to realize the miniaturization and lightweight of electronic products,thus attracting great attention.In this work,we designed a new FeNiBCuSi formulation with a novel atomic ratio,and the microstructure evolution and magnetic softness were investigated.Microstructure analysis revealed that the amount of Si prompted the differential chemical fluctuations of Cu element,favoring the different nucleation and growth processes ofα-Fe nanocrystals.Furthermore,microstructural defects associated with chemical heterogeneities were unveiled using the Maxwell-Voigt model with two Kelvin units and one Maxwell unit based on creeping analysis by nanoindentation.The defect,with a long relaxation time in relaxation spectra,was more likely to induce the formation of crystal nuclei that ultimately evolved into theα-Fe nanocrystals.As a result,Fe_(84)Ni_(2)B_(12.5)Cu_(1)Si_(0.5)alloy with refined uniform nanocrystalline microstructure exhibited excellent magnetic softness,including a high B_(s)of 1.79 T and very low H_(c)of 2.8 A/m.Our finding offers new insight into the influence of activated defects associated with chemical heterogeneities on the microstructures of nanocrystalline alloy with excellent magnetic softness.
基金supported by the Beijing Natural Science Foundation(Grant No.3232011)the Joint Fund of the Ministry of Education for Equipment Pre-research(Grant No.8091B02022306)the National Natural Science Foundation of China(Grant No.52175284).
文摘To investigate the influences of Cr_(2)AlC mass fraction and supersonic plasma spraying process on the microstructure and mechanical properties of Cr_(2)AlC reinforced 410 stainless steel composite coatings,the coatings containing different mass fractions of Cr_(2)AlC were prepared and investigated.The composite coating exhibited low porosity and high adhesion strength.The addition of Cr_(2)AlC significantly enhanced the hardness of the composite coatings through particle strengthening.However,when the mass fraction of Cr_(2)AlC was 20%,the aggregation of Cr_(2)AlC resulted in a strong decrease in the coating preparation efficiency,as well as a decline in adhesion strength.In the supersonic plasma spraying process,the Ar flow rate mainly influenced the flight velocity of the particles,while the H_(2) flow rate and the current mainly affected the temperature of the plasma torch.Consequently,all of them influenced the melting degree of particles and the quality of the coating.The lowest porosity and the highest hardness and adhesion strength could be obtained when the Ar flow rate is 125 L/min,the H_(2) flow rate is 25 L/min,and the current is 385 A.
基金financially supported by the Research and Development Institute at Sakon Nakhon Rajabhat University,as well as by the National Research Council of Thailand(NRCT)(N42A650196).
文摘This research investigates the potential of blending complementary lard oil with rubber seed oil as feedstock for biodiesel production.Rubber seed oil,obtained through hexane extraction using the Soxhlet method,contains the major fatty acids of oleic acid(C_(18:1)),palmitic acid(C_(16:0)),linoleic acid(C_(18:2)),and stearic acid(C_(18:0)),while rubber seed oil primarily consists of linoleic acid(C_(18:2)),oleic acid(C_(18:1)),linolenic acid(C_(18:3)),palmitic acid(C_(16:0)),and stearic acid(C_(18:0)).The least acid value of lard oil(0.55 mg KOH/g)can benefit of reducing soap formation of rubber seed oil during transesterification process in biodiesel production due to its substantial-high acid value(16.28 mg KOH/g).Blending at ratios below 80:20 volume ratio produced biodiesel exceeding 85%,utilizing CaO as a catalyst.Lard oil demonstrated a higher reaction rate constant(11.88×10^(-3)min^(-1))than rubber seed oil(2.11×10^(-3)min^(-1)),indicating a significant difference in performance.High acid value and free fatty acids in rubber seed oil correlated with lower reaction rates.Maintaining a mixture ratio below 80:20 volume ratio optimized reaction rates during biodiesel production.Biodiesel obtained from blends below 80:20 volume ratio met ASTM D6751 and EN 14214 standards,demonstrating suitability for bio-auto fuel.The drawbacks of using rubber seed oil as a raw material for biodiesel production are overcome by blending with lard oil,giving rise to expanding renewable energy options for rural communities,community enterprises,and large-scale biodiesel production.
基金The authors are grateful for financial support from the National Natural Science Foundation of China(52202199)Anhui Provincial Natural Science Foundation(2108085QE202)start-up grants from Anhui University(S020318008/007,S020118002/060).
文摘All-solid-state sodium(Na)-metal batteries(ASSSMBs)are considered promising candidates for large-scale energy storage systems due to their abundant sodium resources,unparalleled safety performance,and impressive energy density.Na superionic conductors(NASICONs)are among the best enablers of ASSSMBs in view of their high ionic conductivity,ease of synthesis,and excellent thermal stability and good electrochemical/chemical compatibility with common electrodes.However,challenges surrounding the NASICON/electrode interface,such as high interfacial resistance and dendrite formation,have hindered the development of practical ASSSMBs based on NASICONs.This review starts with an explicit summary of the interface problems between the metallic Na anode and NASICON arising from mechanical,chemical,and electrochemical aspects(i.e.,poor interface contact,insulating side-reaction products,and irregular dendrite growth).Subsequently,we systematically analyze and logically categorize modification strategies for addressing anode interface problems and provide a comprehensive discussion on the underlying enhancement mechanisms.As such,we identify underlying and universal interface enhancement mechanisms by comparatively studying various modification strategies.Furthermore,we briefly summarize the challenges in the cathode/electrolyte interface and early-stage research efforts in constructing stable cathode/electrolyte interface and fabricating high-performance composite cathodes.Finally,key suggestions and future prospectives for the advancement of NASICON-based ASSSMBs are outlined.
文摘The corrosion resistance of 2024-T3 aluminum alloy was improved by anodizing treatment in a mixed electrolyte containing 10% sulfuric acid, 5% boric acid and 2% phosphoric acid. Electrochemical impedance spectroscopy （EIS） technique was used to study the corrosion behavior of the anodized alloy. Using Tafel plot and salt spray techniques, it is revealed that the anodizing treatment of 2024-T3 aluminum alloy in sulfuric-boric-phosphoric acids provides better corrosion resistance and durability in comparison with the anodizing treatment in phosphoric acid or sulfuric-boric acids. This electrolyte can be a suitable alternative for chromate baths which are generally used in the anodizing of aluminum alloys.
基金The project was financially supported by the Hi-tech Research and Development Program of China (No. G2002AA336080) and the National Natural Science Foundation of China (No. 50374012)
文摘The semi-solid slurry of a hypoeutectic Al-Si alloy was manufactured by low superheat pouring and weak electromagnetic stirring. The effects of pouting temperature and stirring power on the semi-solid slurry were investigated. The results indicated that the semi-solid slurry to satisfy rheocasting can be manufactured by low superheat pouring and weak electromagnetic stirring. The pouring temperature （or superheat） and the stirring power remarkably affected the morphology of primary α-Al and the size of primary α-Al, and there is no obvious effect of stirring time on primary α-Al. Compared with the samples made by low superheat pouring with no stirring, the nucleation rate, particle morphology and grain size of primary α-Al in A356 were markedly improved by low superheat pouring and weak electromagnetic stirring. On the condition of weak electromagnetic stirring, the pouring temperature with low superheat can be suitably raised to reach the effectiveness obtained from the lower pouring temperature without stirring.
文摘The effects of the deformation in the non-recrystallization region of austenite and the cooling rate on the transformation behavior and microstructure of low-carbon low-alloy steel for pipeline application were studied on the thermal-mechanical simulator Gleeble-1500. It was shown that an increase in deformation amount can greatly increase the nucleation site of ferrite when deformed in the non-recrystallization region of austenite, and an increase in nucleation ratio can greatly refine grains. When the cooling rate is accelerated, the driving force of nucleation is increased and the nucleation rate also improves. Ultra-refine grains can be obtained by controlled rolling. The high density of ferrite nucleus, which forms along the austenite grain boundary, twin interface, and deformation band are introduced in the matrix of austenite by the control of hot rolling, after which the microstructure can be refined. It was found that the acicular ferrite has a very fine sub-structure, high dislocation density, and a thin slab with ultra-fine grains. Small M/A islands and cementite are precipitated on the matrix of the slabs by the analysis technique of TEM and SEM.
文摘The magnesium alloy is prone to burn during die-casting, which limits its applications severely, so the effect of adding rare earth （RE） on the ignition-proof of AZ91D Mg alloy is studied. The results indicate that the addition of mischmetal RE elements has a remarkable influence on the ignition-proof property of the magnesium alloy. It is found that the ignition temperature of the magnesium alloy can be greatly raised by adding a proper amount of RE. When the amount is 0.1wt%, the ignition temperature reaches 877℃ which is 206℃ higher than that of AZ91D without RE and the mechanical properties of the alloy are also improved, However, the amount of RE must be properly controlled because too much RE would induce grain coarsening and reduce the mechanical properties.
文摘The kinetics of isothermal reduction of Ag2O with graphite under argon atmosphere for a non-activated sample and mechanically activated sample was investigated.It is found that Johnson-Mehl-Avrami model appropriately explained the thermal and mechanochemical synthesis of Ag from Ag2O＋ghraphite mixture.The process kinetics was investigated using the same approach for milled and unmilled samples.The results show that the Avrami exponent of mechanochemical reduction is higher than that of high temperature thermal reduction.Also,the mechanisms of nuclei growth in thermal and mechanochemical reduction are diffusion controlled and interface controlled,respectively.
基金National Natural Science Foundation of China under Grants 51875518,81501607 and 51475419Key Research and Develop mem Projects of Zhejiang Province under Grant 2017C01054.
文摘The advancement in the materials manufacturing at micrometer and nanometer scales has already enabled numerous applications in electronics, optics, chemistry, biology and medicine. Biomedical devices carrying micro-/nanostructures are currently being widely used in drug delivery, drug release, biosensing and therapy. New clinical methods for disease diagnosis and treatments are being developed enabled by nanotech no logy. One-dimensional (ID) structures are playi ng an importa nt role in the direct drug delivery both in vivo and ex vivo among various micro-/nanostructures. Here, in this paper, we reviewed recent progresses made on next-generation intradermal and intracellular delivery strategies and applications with focus on ID microstructure-based approaches.
基金This work was financially supported by the National Natural Science Foundation of China (No. 50334010)
文摘The microstructure, mechanical properties, and misorientation of automobile beam steels produced by EAF-CSP process were studied using optical microscopy （OM） and electron back-scattered diffraction （EBSD）. It is shown that the microstructure of strips is mainly polygonal ferrite, and the average grain size is about 5-8 μm. The electron back-scattered diffraction results show that grain boundaries in ferrite are basically high-angle grain boundaries without remarkable preferred orientation. Hot strips of automobile beam steels possess a good combination of strength and plasticity because of their fine microstructures and low quantity of impurities.
文摘The cermet composites WC-20wt%Co/ZrO2（E6）with four different comtents of ZrO2（3Y）were prepared by normal vacuum sinter processing;the optical microscope and SEMwere used to characterize their microstructures.The hardness.bending strength and impact toughness of the specimens were determined.The experimental results show that ZrO2（3Y） particles in WC-20wt%Co matrix are sphcrical particles in different sizes which are distributed uniformly in Co phases and WC phases,the bending strength and impact toughness of the WC-20wt%Co cermet composites added ZrO2（3Y）improve remarkably.but the hardness values have little change.
