To elucidate the effect of calcite-regulated activated carbon(AC)structure on low-temperature denitrification performance of SCR catalysts,this work prepared a series of Mn-Ce/De-AC-xCaCO_(3)(x is the calcite content ...To elucidate the effect of calcite-regulated activated carbon(AC)structure on low-temperature denitrification performance of SCR catalysts,this work prepared a series of Mn-Ce/De-AC-xCaCO_(3)(x is the calcite content in coal)catalysts were prepared by the incipient wetness impregnation method,followed by acid washing to remove calcium-containing minerals.Comprehensive characterization and low-temperature denitrification tests revealed that calcite-induced structural modulation of coal-derived AC significantly enhances catalytic activity.Specifically,NO conversion increased from 88.3%of Mn-Ce/De-AC to 91.7%of Mn-Ce/De-AC-1CaCO_(3)(210℃).The improved SCR denitrification activity results from the enhancement of physicochemical properties including higher Mn^(4+)content and Ce^(4+)/Ce^(3+)ratio,an abundance of chemisorbed oxygen and acidic sites,which could strengthen the SCR reaction pathways(richer NH_(3)activated species and bidentate nitrate active species).Therefore,NO removal is enhanced.展开更多
Hydrogel scaffolds have numerous potential applications in the tissue engineering field.However,tough hydrogel scaffolds implanted in vivo are seldom reported because it is difficult to balance biocompatibility and hi...Hydrogel scaffolds have numerous potential applications in the tissue engineering field.However,tough hydrogel scaffolds implanted in vivo are seldom reported because it is difficult to balance biocompatibility and high mechanical properties.Inspired by Chinese ramen,we propose a universal fabricating method(printing-P,training-T,cross-linking-C,PTC&PCT)for tough hydrogel scaffolds to fill this gap.First,3D printing fabricates a hydrogel scaffold with desired structures(P).Then,the scaffold could have extraordinarily high mechanical properties and functional surface structure by cycle mechanical training with salting-out assistance(T).Finally,the training results are fixed by photo-cross-linking processing(C).The tough gelatin hydrogel scaffolds exhibit excellent tensile strength of 6.66 MPa(622-fold untreated)and have excellent biocompatibility.Furthermore,this scaffold possesses functional surface structures from nanometer to micron to millimeter,which can efficiently induce directional cell growth.Interestingly,this strategy can produce bionic human tissue with mechanical properties of 10 kPa-10 MPa by changing the type of salt,and many hydrogels,such as gelatin and silk,could be improved with PTC or PCT strategies.Animal experiments show that this scaffold can effectively promote the new generation of muscle fibers,blood vessels,and nerves within 4 weeks,prompting the rapid regeneration of large-volume muscle loss injuries.展开更多
The study of BiFeO_(3)-0.3BaTiO_(3) ceramics has gained significant attention due to their high Curie temperature(TC≥450℃)and excellent piezoelectric properties(d33≥200 pC·N^(−1)).These are particularly pronou...The study of BiFeO_(3)-0.3BaTiO_(3) ceramics has gained significant attention due to their high Curie temperature(TC≥450℃)and excellent piezoelectric properties(d33≥200 pC·N^(−1)).These are particularly pronounced near the morphotropic phase boundary(MPB)region where coexisting rhombohedral and pseudocubic(R-PC)phases are observed.In addition,as the BaTiO_(3) content increases,BiFeO_(3)-BaTiO_(3) ceramics gradually become dominated by a single pseudocubic(PC-)phase.This shift results in a decrease in piezoelectric properties but an enhancement in strain performance.However,the underlying mechanism remains unclear.The high strain properties observed in non-MPB compositions provide a motivation for further investigation into these mechanisms.This paper presents a detailed analysis of the electric-field and temperature-induced domain structure evolution in BiFeO_(3)-0.4BaTiO_(3),which is predominately characterized by the PC phase.Piezoresponse force microscope(PFM)observations reveal the presence of nanodomains and stripy domains associated with polar nanoregions(PNRs),as well as relaxor ferroelectrics(RFEs)and/or ferroelectrics(FEs).The RFEs exhibit a significantly better strain response than the FEs,providing direct evidence for the enhanced strain properties of RFEs.Elevated-temperature Raman spectroscopy confirms a decrease in B-O bonding and BO6 deformation,along with an increase in structural symmetry,indicating the formation of RFEs and/or PNRs.The phase diagram shows the Burns temperature(TB),dielectric maxima temperature(Tm)and freezing temperature(Tf)evaluated from the dielectric spectra;the temperature-induced evolution of domain structures;and the sequential quasi-dielectric states:PNRs,RFEs and FEs.The evolution of the domain structure,including the morphology and ratio of FEs,RFEs and PNRs,induced by either electric-fields or temperature strongly affects the strain properties of RFEs.A superior piezoelectric coefficient of d33*=533 pm·V^(−1) at 40 kV·cm^(−1) and a large electric strain of Suni=0.285%are obtained.These results further validate that domain modulation can effectively enhance the strain properties of BiFeO_(3)-BaTiO_(3) ceramics,which makes them promising candidates for actuator applications.展开更多
Throughout the 20th century, several large megathrust earthquakes were observed in the Colombia–Ecuador subduction zone which widely ruptured plate interfaces, causing considerable damage and loss of life. The occurr...Throughout the 20th century, several large megathrust earthquakes were observed in the Colombia–Ecuador subduction zone which widely ruptured plate interfaces, causing considerable damage and loss of life. The occurrence of earthquakes in subduction zones is thought to be closely related to the thermal structure of the incoming plate. However, in the case of the subducting Nazca Plate beneath the Colombia–Ecuador zone, the thermal structure remains unclear, especially its hydraulic distribution. On the basis of 3D thermal models, we present new insights into the plate interface conditions of Colombia–Ecuador interplate and megathrust earthquakes. We show that the plate geometry strongly affects the along-strike thermal structure of the slab beneath Colombia and Ecuador, with the subduction of the Carnegie Ridge playing an important role. Our results further reveal that the unique geometry of the Nazca Plate is the primary reason for the relatively high temperatures of the slab beneath Colombia. We suggest that the positions of the100–200 ℃ and 350–450 ℃ isotherms on the plate interface determine the updip and downdip limits of the seismogenic zone. For Colombia–Ecuador interplate earthquakes, the released fluids control the distribution of shallow-depth earthquakes, whereas the age and geometry of the slab control the distribution of intermediate-depth earthquakes. The average temperature of the plate interface at the upper limit of large megathrust earthquakes is hotter than previously thought, which is more consistent with our understanding of the Colombia–Ecuador subduction zone. We predict that the potential location of future large seismic events could be in the rupture zone of past seismic events or offshore of northern Colombia.展开更多
Designing cathode possessing crystalline@amorphous core-shell structure with both active core and shell is a meaningful work for resolving the low specific capacity,unstable cycling performance and sluggish reaction ki...Designing cathode possessing crystalline@amorphous core-shell structure with both active core and shell is a meaningful work for resolving the low specific capacity,unstable cycling performance and sluggish reaction kinetics issues of rechargeable magnesium batteries(RMBs)by providing more active sites as well as releasing inner stress during cycling.Herein,WO_(3)@WO_(3-x)S_(x) owning crystalline@amorphous core-shell structure containing both active core and active shell is constructed successfully by introducing S into metastable WO3 structure under temperaturefield applying.In such structure,amorphous shell would provide continuous Mg^(2+)diffusion channels due to its isotropy property for most Mg^(2+)migrating rapidly to interface and then adsorb at ions reservoir formed by interfacial electricfield for increasing specific capacity.It also makes security for stable structure of WO_(3)@WO_(3-x)S_(x) by alleviating volume expansion of crystalline core WO_(3) during cycling to prolong cycling life.Additionally,“softer”ions S^(2-)would weaken interaction between hard acid Mg^(2+) and ionic lattice to enhance Mg^(2+)storage kinetics.Therefore,WO_(3)@WO_(3-x)S_(x) delivers the superior cycling performance(1000 cycles with 83.3%),rate capability(88.5 mAh g^(-1) at 1000 mA g^(-1))and specific capacity(about 150 mAh g^(-1) at 50 mA g^(-1)),which is near 2 times higher than that of WO3.It is believed that the crystalline@amorphous core-shell structure with both active core and shell designing via doping strategy is enlightening for the development of high-performance RMBs,and such design can be extended to other energy storage devices for better electrochemical performance.展开更多
The 3-sheet structure of Inconel 718 superalloy will be used in flying vehicles as heat resisting and shielding structure due to its lightweight, high strength and stiffness. The 3-sheet structure of Inconel 718 super...The 3-sheet structure of Inconel 718 superalloy will be used in flying vehicles as heat resisting and shielding structure due to its lightweight, high strength and stiffness. The 3-sheet structure of Inconel 718 superalloy processed by LBW/SPF (laser beam welding/superplastic forming) technology exhibited good configuration and uniform thickness distribution. The LBW parameters for 3-sheet structure were as follows: Pulse frequency was 32 Hz, impulse duration 3 ms, peak power per pulse 4500 W, and welding speed 180 mm/min. The SPF parameters were as follows: Temperature T=965°C, forming pressure P=4.2 MPa, and forming time t=130 min. The microstructure in weld fusion zone was constituted of austenite dendritics and Laves phase precipitated in interdendritics. After the SPF process, austenite dendritics in the weld fusion became coarser and most of Laves phases were dissolved and turned into δ precipitated phase, but a few of Laves phases were still reserved. And Nb concentration in dendritics increased to 5.42% compared to 2.82% in as-weld condition. Weld metal Vickers-hardness increased from 331.63 in as-weld condition to 391.74 in post-SPF condition which was closed to the base material Vickers-hardness of post-SPF. Grain size of base material grew slightly and an amount of precipitated phase appeared in the base material undergoing SPF process. The tensile test results of base material showed that tensile strength increased obviously and the ductility decreased slightly after SPF process. Load response test results indicated that the 3-sheet structure possessed good resistance to compression and bending load. Accordingly, the LBW/SPF technology is an appropriate forming technique for the 3-sheet structure of Inconel 718 superalloy.展开更多
Hierarchical porous structure,which include macropores,minor pores,and micropores in scaffolds,are essential in the multiple biological functions of bone repair and regeneration.In this study,patientcustomized calcium...Hierarchical porous structure,which include macropores,minor pores,and micropores in scaffolds,are essential in the multiple biological functions of bone repair and regeneration.In this study,patientcustomized calcium-deficient hydroxyapatite(CDHA)scaffolds with three-level hierarchical porous structure were fabricated by indirect 3D printing technology and particulate leaching method.The sacrificial template scaffolds were fabricated using a photo-curing 3D printer,which provided a prerequisite for the integral structure and interconnected macropores of CDHA scaffolds.Additionally,20 wt%pore former was incorporated into the slurry to enhance the content of smaller pores within the CDHA-2 scaffolds,and then the CDHA-2 scaffolds were sintered to remove the sacrificial template scaffolds and pore former.The obtained CDHA-2 scaffolds exhibited interconnected macropores(300-400μm),minor pores(∼10-100μm),and micropores(<10μm)distributed throughout the scaffolds,which could promote bone tissue ingrowth,increase surface roughness,and enhance protein adsorption of scaffolds.In vitro studies identified that CDHA-2 scaffolds had nanocrystal grains,high specific surface area,and outstanding protein adsorption capacity,which could provide a microenvironment for cell adhesion,spreading,and proliferation.In addition,the murine intramuscular implantation experiment suggested that CDHA-2 scaffolds exhibited excellent osteoinductivity and were superior to traditional BCP ceramics under conditions without the addition of live cells and exogenous growth factors.The rabbit calvarial defect repair results indicated that CDHA-2 scaffolds could enhance in situ bone regeneration.In conclusion,these findings demonstrated that the hierarchical porous structure of CDHA scaffolds was a pivotal factor in modulating osteoinductivity and bone regeneration,and CDHA-2 scaffolds were potential candidates for bone regeneration.展开更多
In-space 3D printing is transforming the manufacturing paradigm of space structures from ground-based production to in-situ space manufacturing,effectively addressing the challenges of high costs,long response times,a...In-space 3D printing is transforming the manufacturing paradigm of space structures from ground-based production to in-situ space manufacturing,effectively addressing the challenges of high costs,long response times,and structural size limitations associated with traditional rocket launches.This technology enables rapid on-orbit emergency repairs and significantly expands the geometric dimensions of space structures.High-performance polymers and their composites are widely used in in-space 3D printing,yet their implementation faces complex challenges posed by extreme space environmental conditions and limited energy or resources.This paper reviews the state-of-the-art in 3D printing of polymer and composites for on-orbit structure manufacturing.Based on existing research activities,the review focuses on three key aspects including the impact of extreme space environments on forming process and performance,innovative design and manufacturing methods for space structures,and on-orbit recycling and remanufacturing of raw materials.Some experiments that have already been conducted on-orbit and simulated experiments completed on the ground are systematically analyzed to provide a more comprehensive understanding of the constraints and objectives for on-orbit structure manufacturing.Furthermore,several perspectives requiring further research in future are proposed to facilitate the development of new in-space 3D printing technologies and space structures,thereby supporting increasingly advanced space exploration activities.展开更多
03-type layered oxide serves as dominant components in sodium ion batteries;however,the unstable electronic structure between transition metal and oxygen inevitably induces framework instability and severe kinetic hin...03-type layered oxide serves as dominant components in sodium ion batteries;however,the unstable electronic structure between transition metal and oxygen inevitably induces framework instability and severe kinetic hindrance.In this study,a two-in-one approach to synergistically modulate the local electro nic and interfacial structure of NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)by Ce modification is proposed.We present an indepth study to reveal the strong-covalent Ce-O bonds,which make local charge around oxygen more negative,enhance O 2p-Mn 3d hybridization,and preserve the octahedral structural integrity.This modification tailors local electronic structure between the octahedral metal center and oxygen,thus enhancing reversibility of 03-P3-03 phase transition and expanding Na+octahedral-tetrahedral-octahedral transport channel.Additionally,the nanoscale perovskite layer induced by Ce element is in favor of minimizing interfacial side reaction as well as enhancing Na^(+)diffusivity.As a result,the designed 03-NaNi_(0.305)Fe_(0.33)Mn_(0.33)Ce_(0.025)O_(2)material delivers an exceptionally low volume variation,an ultrahigh rate capacity of 76.9 mA h g^(-1)at 10 C,and remarkable cycling life over 250 cycles with capacity retention of 80% at 5 C.展开更多
Lithium(Li)metal is considered the most promising anode material for the next generation of secondary batteries due to its high theoretical specific capacity and low potential.However,the application of Li anode in re...Lithium(Li)metal is considered the most promising anode material for the next generation of secondary batteries due to its high theoretical specific capacity and low potential.However,the application of Li anode in rechargeable Li metal batteries(LMBs)is hindered due to the short cycle life caused by uncontrolled dendrite growth.In this work,a dendrite-free anode(Li–Sn/Cu)is reinforced synergistically by lithophilic alloy,and a 3D grid structure is designed.Li^(+)diffusion and uniform nucleation are effectively induced by the lithophilic alloy Li_(22)Sn_(5).Moreover,homogeneous deposition of Li^(+)is caused by the reversible gridded Li plating/stripping effect of Cu mesh.Furthermore,the local space electric field is redistributed throughout the 3D conductive network,whereby the tip effect is suppressed,thus inhibiting the growth of Li dendrites.Also,the volume expansion of the anode during cycling is eased by the 3D grid structure.The results show that the Li–Sn/Cu symmetric battery can stably cycle for more than 10,000 h at 2 mA.cm^(-2)and 1 mAh.cm^(-2)with a low overpotential.The capacity retention of the LiFePO_(4)full battery remains above 90.7%after 1,000 cycles at 1C.This work provides a facile,low-cost,and effective strategy for obtaining Li metal batteries with ultra-long cycle life.展开更多
Transforming a scattering medium into a lens for imaging very simple binary objects is possible;however,it remains challenging to image complex grayscale objects,let alone measure 3D continuous distribution objects.He...Transforming a scattering medium into a lens for imaging very simple binary objects is possible;however,it remains challenging to image complex grayscale objects,let alone measure 3D continuous distribution objects.Here,we propose and demonstrate the use of a ground glass diffuser as a scattering lens for imaging complex grayscale fringes,and we employ it to achieve microscopic structured light 3D imaging(MSL3DI).The ubiquitous property of the speckle patterns permits the exploitation of the scattering medium as an ultra-thin scattering lens with a variable focal length and a flexible working distance for microscale object measurement.The method provides a light,flexible,and cost-effective imaging device as an alternative to microscope objectives or telecentric lenses in conventional MSL3DI systems.We experimentally demonstrate that employing a scattering lens allows us to achieve relatively good phase information and robust 3D imaging from depth measurements,yielding measurement accuracy only marginally lower than that of a telecentric lens,typically within approximately 10μm.Furthermore,the scattering lens demonstrates robust performance even when the imaging distance exceeds the typical working distance of a telecentric lens.The proposed method facilitates the application of scattering imaging techniques,providing a more flexible solution for MSL3DI.展开更多
The influence of the growth of rare earth on the viscosity during the uniform cooling of CaO-SiO_(2-)CaF_(2)-Ce_(2)O_(3)slag was investigated by the high temperature viscometer.The results show that Ce_(2)O_(3)affects...The influence of the growth of rare earth on the viscosity during the uniform cooling of CaO-SiO_(2-)CaF_(2)-Ce_(2)O_(3)slag was investigated by the high temperature viscometer.The results show that Ce_(2)O_(3)affects the viscosity variedly before and after the break temperature.At higher temperatures Ce_(2)O_(3)reduces the viscosity.When the temperature is below the break temperature,at a Ce_(2)O_(3)content of≥3 mol%,a rareearth crystalline phase is observed during the slag cooling process,and the break temperature progressively increases with the increase of Ce_(2)O_(3)concentration.There are no crystallized rare earths in the slag under the condition of Ce_(2)O_(3)concentration lower than 3 mol%.Too low or too high CaF_(2)content is found to be unfavorable for rare-earth crystallisation.The increase of Ce_(2)O_(3)content facilitates the depolymerization of silica-oxygen tetrahedral structure.Ca-F bond exists between structural units,weakening the flow resistance of structural units and lowering the viscosity of slag.展开更多
Herein we report novel photocatalysts ZnIn_(2)S_(4)-Ag-LaFeO_(3) with the core-shell structured materials prepared by hydrothermal method.In order to improve the efficiency of photocatalytic degradation of pollutants,...Herein we report novel photocatalysts ZnIn_(2)S_(4)-Ag-LaFeO_(3) with the core-shell structured materials prepared by hydrothermal method.In order to improve the efficiency of photocatalytic degradation of pollutants,LaFeO_(3) was prepared by hydrothermal followed by calcination,and further Ag nanoparticle(NP)was loaded onto the spherical structure of LaFeO_(3) by photolysis of silver nitrate,and finally the spherical Znln_(2)S_(4)-Ag-LaFeO_(3) photocatalyst was prepared by hydrothermal method again.The structure and properties of the as-prepared materials were characterized by X-ray photoelectron spectroscopy,ultraviolet-visible absorption spectroscopy,X-ray diffraction,scanning electron microscopy and fluorescence spectra.The results show that the synthesized composite photocatalysts display a significant improvement in photocatalytic efficiency relative to the single LaFeO_(3) and ZnIn_(2)S_(4)and form a core-shell structure.Furthermore,the effect of the ratio of each component on the photocatalytic efficiency was investigated in detail,and it is discovered that at an Methylene Blue(MB)concentration of 0.219 mol/L,the degradation rate of MB is 95%at 120 min using 0.02 g of catalyst with an ideal ZnIn_(2)S_(4):Ag:LaFeO_(3)ratio of 10:0.5:1.The possible mechanisms to improve the photocatalytic efficiency were explored.展开更多
Structural modification of three dimensional(3D)materials for the application of dielectric loss-based microwave absorbing materials(MAMs)usually relies on intricate synthesis process and can pose challenges in terms ...Structural modification of three dimensional(3D)materials for the application of dielectric loss-based microwave absorbing materials(MAMs)usually relies on intricate synthesis process and can pose challenges in terms of scalability and mass production for practical application.In this work,we reported a successful attempt in modifying the 3D structure of mesoporous lanthanum oxide(La_(2)O_(3))for effective broadband MAMs candidate via simple co-precipitation process.The inclusion of cetyltrimethylammonium bromide(CTAB)and hydrothermal aging treatment result in a significant transformation of La_(2)O_(3)particles from their original polygonal form to a 3D coral-like and nano needle-like structure.The utilization of CTAB and hydrothermal aging results in the increase of surface area and a two-fold increase in pore volume of the resulting La_(2)O_(3).Due to its unique 3D structure,the 3D coral-like and nano needle-like La_(2)O_(3)materials possess a broadband electromagnetic(EM)wave absorption characteristic with the effective absorption bandwidth(EAB)covering the C-band frequency range.Specifically,in the La_(2)O_(3)C-H sample(with CTAB-with hydrothermal),it exhibits strong EM wave absorption with a reflection loss(RL)value of-33.07 dB which equals to 99.95%EM wave absorption at a thickness of only 1.50 mm.The detailed analysis of EM wave absorption properties reveals that the improvement of La_(2)O_(3)materials to attenuate EM wave energy arises from the dielectric loss phenomenon,the enhanced interfacial polarization,multiple reflections mechanism,and conduction loss mechanism induced by the 3D structural formation of the La_(2)O_(3)structure.This work proposes a novel and efficient approach in synthesizing and modifying 3D materials for effective broadband EM wave absorption.展开更多
In response to the limitations of conventional chemical synthesis methods for the structural modulation of nanomaterials,an innovative high magnetic field-assisted wet chemical synthesis method was proposed to prepare...In response to the limitations of conventional chemical synthesis methods for the structural modulation of nanomaterials,an innovative high magnetic field-assisted wet chemical synthesis method was proposed to prepare NiFe_(2)O_(4)/Fe_(2)O_(3) heterostructures.It is found that the high-energy physical field could induce a more homogeneous morphology of NiFe_(2)O_(4)/Fe_(2)O_(3),accompanied by phase transformation from Fe_(2)O_(3) to NiFe_(2)O_(4).As a result,the optimized structure obtained under the magnetic field endows NiFe_(2)O_(4)/Fe_(2)O_(3) with enhanced performance for the lithium-ion battery anode,as evidenced by an increase of 16%(1200 mA·h/g)in discharge capacity and 24% in ultra-stable cycling performance(capacity retention of 97.1%).These results highlight the feasibility of high magnetic fields in modulating material structure and enhancing lithium storage performance.展开更多
The magnetic refrigeration(MR)based on the principle of magnetocaloric effect(MCE)in magnetic materials was recognized as an alternative cooling way to our present commercialized vapor compression cycle technology.Evi...The magnetic refrigeration(MR)based on the principle of magnetocaloric effect(MCE)in magnetic materials was recognized as an alternative cooling way to our present commercialized vapor compression cycle technology.Evidently,a vital prerequisite for practical applications is the exploration of candidate materials with prominent magnetocaloric performances.In this paper,the polycrystalline garnet RE_(3)Al_(5)O_(12)(RE=Tb,Dy and Ho)compounds with the cubic structure(space group:Ia3d)were prepared using the Pechini sol-gel method,and their crystal structure,magnetic properties and comprehensive magnetocaloric performances were studied.The analysis of magnetic susceptibility curves in a static magnetic field H=0.1 T reveal that the Dy_(3)Al_(5)O_(12)undergoes antiferromagnetic transition with Néel temperature TN≈2.6 K,whereas the Tb_(3)Al_(5)O_(12)and Ho_(3)Al_(5)O_(12)exhibit no features indicative of the magnetic ordering processes down to 1.8 K.The comprehensive magnetocaloric performances,namely the maximum magnetic entropy change and relative cooling power,are derived indirectly from the isothermal field-dependent magnetization data,which yield 11.72,10.42,7.53 J/(kg·K)and 84.56,69.52,70.35 J/kg for the Tb_(3)Al_(5)O_(12),Dy_(3)Al_(5)O_(12)and Ho_(3)Al_(5)O_(12)under a low field change(ΔH)of 0-2 T,respectively.The superior comprehensive magnetocaloric performances and wide operating temperature range of these compounds under lowΔH make them attractive for cryogenic MR technology.展开更多
Due to many remarkable physical and chemical properties,two-dimensional(2D)nanomaterials have become a hot spot in the field of condensed matter physics.In this paper,we have studied the structural,mechanical,and elec...Due to many remarkable physical and chemical properties,two-dimensional(2D)nanomaterials have become a hot spot in the field of condensed matter physics.In this paper,we have studied the structural,mechanical,and electronic properties of the 2D GaInO_(3)system by first-principles method.We find that 2D Ga InO_(3)can exist stably at ambient condition.Molecular dynamic simulations show that GaInO_(3)-sheet has excellent thermal stability and is stable up to1100 K.Electronic structural calculations show that GaInO_(3)-sheet has a band gap of 1.56 eV,which is close to the ideal band gap of solar cell materials,demonstrating great potential in future photovoltaic application.In addition,strain effect studies show that the GaInO_(3)-sheet structure always exhibits a direct band gap under biaxial compressive strain,and as the biaxial compressive strain increases,the band gap gradually decreases until it is converted into metal.While biaxial tensile strain can cause the 2D material to transform from a direct band gap semiconductor into an indirect band gap semiconductor,and even to metal.Our research expands the application of the Ga InO_(3)system,which may have potential application value in electronic devices and solar energy.展开更多
Methods and procedures of three-dimensional （3D） characterization of the pore structure features in the packed ore particle bed are focused. X-ray computed tomography was applied to deriving the cross-sectional imag...Methods and procedures of three-dimensional （3D） characterization of the pore structure features in the packed ore particle bed are focused. X-ray computed tomography was applied to deriving the cross-sectional images of specimens with single particle size of 1-2, 2-3, 3-4, 4-5, 5-6, 6-7, 7-8, 8-9, 9-10 ram. Based on the in-house developed 3D image analysis programs using Matlab, the volume porosity, pore size distribution and degree of connectivity were calculated and analyzed in detail. The results indicate that the volume porosity, the mean diameter of pores and the effective pore size （d50） increase with the increasing of particle size. Lognormal distribution or Gauss distribution is mostly suitable to model the pore size distribution. The degree of connectivity investigated on the basis of cluster-labeling algorithm also increases with increasing the particle size approximately.展开更多
The rapid solidification process of Mg7Zn3 alloy was simulated by the molecular dynamics method. The relationship between the local structure and the dynamics during the liquid-glass transition was deeply investigated...The rapid solidification process of Mg7Zn3 alloy was simulated by the molecular dynamics method. The relationship between the local structure and the dynamics during the liquid-glass transition was deeply investigated. It was found that the Mg-centered FK polyhedron and the Zn-centered icosahedron play a critical role in the formation of Mg7Zn3 metallic glass. The self-diffusion coefficients of Mg and Zn atoms deviate from the Arrhenius law near the melting temperature and then satisfy the power law. According to the time correlation functions of mean-square displacement, incoherent intermediate scattering function and non-Gaussian parameter, it was found that the β-relaxation in Mg7Zn3 supercooled liquid becomes more and more evident with decreasing temperature, and the α-relaxation time rapidly increases in the VFT law. Moreover, the smaller Zn atom has a faster relaxation behavior than the Mg atom. Some local atomic structures with short-range order have lower mobility, and they play a critical role in the appearance of cage effect in theβ-relaxation regime. The dynamics deviates from the Arrhenius law just at the temperature as the number of local atomic structures begins to rapidly increase. The dynamic glass transition temperature （Tc） is close to the glass transition point in structure （TgStr）.展开更多
The electronic structure,including band structure,density of states （DOS）, and partial density of states of SrTi1-xSbxO3 with x = 0,0. 125,0.25,and 0.33 is calculated from the first principles of plane wave ultra-so...The electronic structure,including band structure,density of states （DOS）, and partial density of states of SrTi1-xSbxO3 with x = 0,0. 125,0.25,and 0.33 is calculated from the first principles of plane wave ultra-soft pseudo-potential technology based on density function theory. The calculated results reveal that due to the electron doping,the Fermi level moves into the conduction bands for SrTi1-xSbxO3 with x = 0. 125 and the system shows metallic behavior. In addition, the DOS moves towards low energy and the optical band gap is broadened. The wide band gap and the low density of the states in the conduction band result in the transparency of the films.展开更多
基金Supported by the Science and Technology Cooperation and Exchange special project of Cooperation of Shanxi Province(202404041101014)the Fundamental Research Program of Shanxi Province(202403021212333)+3 种基金the Joint Funds of the National Natural Science Foundation of China(U24A20555)the Lvliang Key R&D of University-Local Cooperation(2023XDHZ10)the Initiation Fund for Doctoral Research of Taiyuan University of Science and Technology(20242026)the Outstanding Doctor Funding Award of Shanxi Province(20242080).
文摘To elucidate the effect of calcite-regulated activated carbon(AC)structure on low-temperature denitrification performance of SCR catalysts,this work prepared a series of Mn-Ce/De-AC-xCaCO_(3)(x is the calcite content in coal)catalysts were prepared by the incipient wetness impregnation method,followed by acid washing to remove calcium-containing minerals.Comprehensive characterization and low-temperature denitrification tests revealed that calcite-induced structural modulation of coal-derived AC significantly enhances catalytic activity.Specifically,NO conversion increased from 88.3%of Mn-Ce/De-AC to 91.7%of Mn-Ce/De-AC-1CaCO_(3)(210℃).The improved SCR denitrification activity results from the enhancement of physicochemical properties including higher Mn^(4+)content and Ce^(4+)/Ce^(3+)ratio,an abundance of chemisorbed oxygen and acidic sites,which could strengthen the SCR reaction pathways(richer NH_(3)activated species and bidentate nitrate active species).Therefore,NO removal is enhanced.
基金supported by the Innovative Research Group Project of the National Natural Science Foundation of China(T2121004)Key Programme(52235007)National Outstanding Youth Foundation of China(52325504).
文摘Hydrogel scaffolds have numerous potential applications in the tissue engineering field.However,tough hydrogel scaffolds implanted in vivo are seldom reported because it is difficult to balance biocompatibility and high mechanical properties.Inspired by Chinese ramen,we propose a universal fabricating method(printing-P,training-T,cross-linking-C,PTC&PCT)for tough hydrogel scaffolds to fill this gap.First,3D printing fabricates a hydrogel scaffold with desired structures(P).Then,the scaffold could have extraordinarily high mechanical properties and functional surface structure by cycle mechanical training with salting-out assistance(T).Finally,the training results are fixed by photo-cross-linking processing(C).The tough gelatin hydrogel scaffolds exhibit excellent tensile strength of 6.66 MPa(622-fold untreated)and have excellent biocompatibility.Furthermore,this scaffold possesses functional surface structures from nanometer to micron to millimeter,which can efficiently induce directional cell growth.Interestingly,this strategy can produce bionic human tissue with mechanical properties of 10 kPa-10 MPa by changing the type of salt,and many hydrogels,such as gelatin and silk,could be improved with PTC or PCT strategies.Animal experiments show that this scaffold can effectively promote the new generation of muscle fibers,blood vessels,and nerves within 4 weeks,prompting the rapid regeneration of large-volume muscle loss injuries.
基金supported by the National Key Research and Development Program(No.2022YFB3807400)the National Natural Science Foundation of China(Nos.52072028 and 52032007).
文摘The study of BiFeO_(3)-0.3BaTiO_(3) ceramics has gained significant attention due to their high Curie temperature(TC≥450℃)and excellent piezoelectric properties(d33≥200 pC·N^(−1)).These are particularly pronounced near the morphotropic phase boundary(MPB)region where coexisting rhombohedral and pseudocubic(R-PC)phases are observed.In addition,as the BaTiO_(3) content increases,BiFeO_(3)-BaTiO_(3) ceramics gradually become dominated by a single pseudocubic(PC-)phase.This shift results in a decrease in piezoelectric properties but an enhancement in strain performance.However,the underlying mechanism remains unclear.The high strain properties observed in non-MPB compositions provide a motivation for further investigation into these mechanisms.This paper presents a detailed analysis of the electric-field and temperature-induced domain structure evolution in BiFeO_(3)-0.4BaTiO_(3),which is predominately characterized by the PC phase.Piezoresponse force microscope(PFM)observations reveal the presence of nanodomains and stripy domains associated with polar nanoregions(PNRs),as well as relaxor ferroelectrics(RFEs)and/or ferroelectrics(FEs).The RFEs exhibit a significantly better strain response than the FEs,providing direct evidence for the enhanced strain properties of RFEs.Elevated-temperature Raman spectroscopy confirms a decrease in B-O bonding and BO6 deformation,along with an increase in structural symmetry,indicating the formation of RFEs and/or PNRs.The phase diagram shows the Burns temperature(TB),dielectric maxima temperature(Tm)and freezing temperature(Tf)evaluated from the dielectric spectra;the temperature-induced evolution of domain structures;and the sequential quasi-dielectric states:PNRs,RFEs and FEs.The evolution of the domain structure,including the morphology and ratio of FEs,RFEs and PNRs,induced by either electric-fields or temperature strongly affects the strain properties of RFEs.A superior piezoelectric coefficient of d33*=533 pm·V^(−1) at 40 kV·cm^(−1) and a large electric strain of Suni=0.285%are obtained.These results further validate that domain modulation can effectively enhance the strain properties of BiFeO_(3)-BaTiO_(3) ceramics,which makes them promising candidates for actuator applications.
基金benefited from the financial support of the CAS Pioneer Hundred Talents Program and the Second Tibetan Plateau Scientific Expedition and Research Program (2019QZKK0708)。
文摘Throughout the 20th century, several large megathrust earthquakes were observed in the Colombia–Ecuador subduction zone which widely ruptured plate interfaces, causing considerable damage and loss of life. The occurrence of earthquakes in subduction zones is thought to be closely related to the thermal structure of the incoming plate. However, in the case of the subducting Nazca Plate beneath the Colombia–Ecuador zone, the thermal structure remains unclear, especially its hydraulic distribution. On the basis of 3D thermal models, we present new insights into the plate interface conditions of Colombia–Ecuador interplate and megathrust earthquakes. We show that the plate geometry strongly affects the along-strike thermal structure of the slab beneath Colombia and Ecuador, with the subduction of the Carnegie Ridge playing an important role. Our results further reveal that the unique geometry of the Nazca Plate is the primary reason for the relatively high temperatures of the slab beneath Colombia. We suggest that the positions of the100–200 ℃ and 350–450 ℃ isotherms on the plate interface determine the updip and downdip limits of the seismogenic zone. For Colombia–Ecuador interplate earthquakes, the released fluids control the distribution of shallow-depth earthquakes, whereas the age and geometry of the slab control the distribution of intermediate-depth earthquakes. The average temperature of the plate interface at the upper limit of large megathrust earthquakes is hotter than previously thought, which is more consistent with our understanding of the Colombia–Ecuador subduction zone. We predict that the potential location of future large seismic events could be in the rupture zone of past seismic events or offshore of northern Colombia.
基金supported by the National Natural Science Foundation of China under Grant No.52072196,52002200,52102106,52202262,22379081,22379080,Major Basic Research Program of Natural Science Foundation of Shandong Province under Grant No.ZR2020ZD09the Natural Science Foundation of Shandong Province under Grant No.ZR2020QE063,ZR202108180009,ZR2023QE059the Postdoctoral Program in Qingdao under No.QDBSH20220202019.
文摘Designing cathode possessing crystalline@amorphous core-shell structure with both active core and shell is a meaningful work for resolving the low specific capacity,unstable cycling performance and sluggish reaction kinetics issues of rechargeable magnesium batteries(RMBs)by providing more active sites as well as releasing inner stress during cycling.Herein,WO_(3)@WO_(3-x)S_(x) owning crystalline@amorphous core-shell structure containing both active core and active shell is constructed successfully by introducing S into metastable WO3 structure under temperaturefield applying.In such structure,amorphous shell would provide continuous Mg^(2+)diffusion channels due to its isotropy property for most Mg^(2+)migrating rapidly to interface and then adsorb at ions reservoir formed by interfacial electricfield for increasing specific capacity.It also makes security for stable structure of WO_(3)@WO_(3-x)S_(x) by alleviating volume expansion of crystalline core WO_(3) during cycling to prolong cycling life.Additionally,“softer”ions S^(2-)would weaken interaction between hard acid Mg^(2+) and ionic lattice to enhance Mg^(2+)storage kinetics.Therefore,WO_(3)@WO_(3-x)S_(x) delivers the superior cycling performance(1000 cycles with 83.3%),rate capability(88.5 mAh g^(-1) at 1000 mA g^(-1))and specific capacity(about 150 mAh g^(-1) at 50 mA g^(-1)),which is near 2 times higher than that of WO3.It is believed that the crystalline@amorphous core-shell structure with both active core and shell designing via doping strategy is enlightening for the development of high-performance RMBs,and such design can be extended to other energy storage devices for better electrochemical performance.
基金Supported by the National Natural Science Foundation of China (Grant No. 50672106)the Intellectual Innovation Project of the Chinese Academy of Sciences (Grant No. KJCX3-SYW.No.12)
文摘The 3-sheet structure of Inconel 718 superalloy will be used in flying vehicles as heat resisting and shielding structure due to its lightweight, high strength and stiffness. The 3-sheet structure of Inconel 718 superalloy processed by LBW/SPF (laser beam welding/superplastic forming) technology exhibited good configuration and uniform thickness distribution. The LBW parameters for 3-sheet structure were as follows: Pulse frequency was 32 Hz, impulse duration 3 ms, peak power per pulse 4500 W, and welding speed 180 mm/min. The SPF parameters were as follows: Temperature T=965°C, forming pressure P=4.2 MPa, and forming time t=130 min. The microstructure in weld fusion zone was constituted of austenite dendritics and Laves phase precipitated in interdendritics. After the SPF process, austenite dendritics in the weld fusion became coarser and most of Laves phases were dissolved and turned into δ precipitated phase, but a few of Laves phases were still reserved. And Nb concentration in dendritics increased to 5.42% compared to 2.82% in as-weld condition. Weld metal Vickers-hardness increased from 331.63 in as-weld condition to 391.74 in post-SPF condition which was closed to the base material Vickers-hardness of post-SPF. Grain size of base material grew slightly and an amount of precipitated phase appeared in the base material undergoing SPF process. The tensile test results of base material showed that tensile strength increased obviously and the ductility decreased slightly after SPF process. Load response test results indicated that the 3-sheet structure possessed good resistance to compression and bending load. Accordingly, the LBW/SPF technology is an appropriate forming technique for the 3-sheet structure of Inconel 718 superalloy.
基金supported by the National Key Research and Development Program of China(No.2019YFA0110600)the Science and Technology Support Program of Sichuan Province(No.2019YJ0161).
文摘Hierarchical porous structure,which include macropores,minor pores,and micropores in scaffolds,are essential in the multiple biological functions of bone repair and regeneration.In this study,patientcustomized calcium-deficient hydroxyapatite(CDHA)scaffolds with three-level hierarchical porous structure were fabricated by indirect 3D printing technology and particulate leaching method.The sacrificial template scaffolds were fabricated using a photo-curing 3D printer,which provided a prerequisite for the integral structure and interconnected macropores of CDHA scaffolds.Additionally,20 wt%pore former was incorporated into the slurry to enhance the content of smaller pores within the CDHA-2 scaffolds,and then the CDHA-2 scaffolds were sintered to remove the sacrificial template scaffolds and pore former.The obtained CDHA-2 scaffolds exhibited interconnected macropores(300-400μm),minor pores(∼10-100μm),and micropores(<10μm)distributed throughout the scaffolds,which could promote bone tissue ingrowth,increase surface roughness,and enhance protein adsorption of scaffolds.In vitro studies identified that CDHA-2 scaffolds had nanocrystal grains,high specific surface area,and outstanding protein adsorption capacity,which could provide a microenvironment for cell adhesion,spreading,and proliferation.In addition,the murine intramuscular implantation experiment suggested that CDHA-2 scaffolds exhibited excellent osteoinductivity and were superior to traditional BCP ceramics under conditions without the addition of live cells and exogenous growth factors.The rabbit calvarial defect repair results indicated that CDHA-2 scaffolds could enhance in situ bone regeneration.In conclusion,these findings demonstrated that the hierarchical porous structure of CDHA scaffolds was a pivotal factor in modulating osteoinductivity and bone regeneration,and CDHA-2 scaffolds were potential candidates for bone regeneration.
基金supported by National Natural Science Foundation of China(Grant No.52205413)National Key Research and Development Program(Grant No.2022YFB3806101)+1 种基金K C Wong Education FoundationThe Youth Innovation Team of Shaanxi Universities。
文摘In-space 3D printing is transforming the manufacturing paradigm of space structures from ground-based production to in-situ space manufacturing,effectively addressing the challenges of high costs,long response times,and structural size limitations associated with traditional rocket launches.This technology enables rapid on-orbit emergency repairs and significantly expands the geometric dimensions of space structures.High-performance polymers and their composites are widely used in in-space 3D printing,yet their implementation faces complex challenges posed by extreme space environmental conditions and limited energy or resources.This paper reviews the state-of-the-art in 3D printing of polymer and composites for on-orbit structure manufacturing.Based on existing research activities,the review focuses on three key aspects including the impact of extreme space environments on forming process and performance,innovative design and manufacturing methods for space structures,and on-orbit recycling and remanufacturing of raw materials.Some experiments that have already been conducted on-orbit and simulated experiments completed on the ground are systematically analyzed to provide a more comprehensive understanding of the constraints and objectives for on-orbit structure manufacturing.Furthermore,several perspectives requiring further research in future are proposed to facilitate the development of new in-space 3D printing technologies and space structures,thereby supporting increasingly advanced space exploration activities.
基金supported by the Science and technology plan project of Yulin(2023-CXY-193)the Project funded by Shaanxi Postdoctoral Science Foundation(2023BSHEDZZ274)+2 种基金the Shaanxi Province(2023-ZDLGY-24,2023-JC-QN-0588,Z20210201)the Science and technology plan project of Beilin(GX2319)the Science and technology plan project of Ankang(AK2023-GY-08)。
文摘03-type layered oxide serves as dominant components in sodium ion batteries;however,the unstable electronic structure between transition metal and oxygen inevitably induces framework instability and severe kinetic hindrance.In this study,a two-in-one approach to synergistically modulate the local electro nic and interfacial structure of NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)by Ce modification is proposed.We present an indepth study to reveal the strong-covalent Ce-O bonds,which make local charge around oxygen more negative,enhance O 2p-Mn 3d hybridization,and preserve the octahedral structural integrity.This modification tailors local electronic structure between the octahedral metal center and oxygen,thus enhancing reversibility of 03-P3-03 phase transition and expanding Na+octahedral-tetrahedral-octahedral transport channel.Additionally,the nanoscale perovskite layer induced by Ce element is in favor of minimizing interfacial side reaction as well as enhancing Na^(+)diffusivity.As a result,the designed 03-NaNi_(0.305)Fe_(0.33)Mn_(0.33)Ce_(0.025)O_(2)material delivers an exceptionally low volume variation,an ultrahigh rate capacity of 76.9 mA h g^(-1)at 10 C,and remarkable cycling life over 250 cycles with capacity retention of 80% at 5 C.
基金supported by the National Natural Science Foundation of China(No.52401221)Shandong Provincial Natural Science Foundation,China(No.ZR2022QE014)+1 种基金the Basic Scientific Research Fund for Central Universities(No.202112018)the Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education)。
文摘Lithium(Li)metal is considered the most promising anode material for the next generation of secondary batteries due to its high theoretical specific capacity and low potential.However,the application of Li anode in rechargeable Li metal batteries(LMBs)is hindered due to the short cycle life caused by uncontrolled dendrite growth.In this work,a dendrite-free anode(Li–Sn/Cu)is reinforced synergistically by lithophilic alloy,and a 3D grid structure is designed.Li^(+)diffusion and uniform nucleation are effectively induced by the lithophilic alloy Li_(22)Sn_(5).Moreover,homogeneous deposition of Li^(+)is caused by the reversible gridded Li plating/stripping effect of Cu mesh.Furthermore,the local space electric field is redistributed throughout the 3D conductive network,whereby the tip effect is suppressed,thus inhibiting the growth of Li dendrites.Also,the volume expansion of the anode during cycling is eased by the 3D grid structure.The results show that the Li–Sn/Cu symmetric battery can stably cycle for more than 10,000 h at 2 mA.cm^(-2)and 1 mAh.cm^(-2)with a low overpotential.The capacity retention of the LiFePO_(4)full battery remains above 90.7%after 1,000 cycles at 1C.This work provides a facile,low-cost,and effective strategy for obtaining Li metal batteries with ultra-long cycle life.
基金supported by the National Natural Science Foundation of China(Grant Nos.62275188 and 62505216)the Central Guidance on Local Science and Technology Development Fund(Grant No.YDZJSX2024D019)+1 种基金the International Scientific and Technological Cooperative Project in Shanxi Province(Grant No.202104041101009)the Natural Science Foundation of Shanxi Province of China through Research Project(Grant No.20210302123195).
文摘Transforming a scattering medium into a lens for imaging very simple binary objects is possible;however,it remains challenging to image complex grayscale objects,let alone measure 3D continuous distribution objects.Here,we propose and demonstrate the use of a ground glass diffuser as a scattering lens for imaging complex grayscale fringes,and we employ it to achieve microscopic structured light 3D imaging(MSL3DI).The ubiquitous property of the speckle patterns permits the exploitation of the scattering medium as an ultra-thin scattering lens with a variable focal length and a flexible working distance for microscale object measurement.The method provides a light,flexible,and cost-effective imaging device as an alternative to microscope objectives or telecentric lenses in conventional MSL3DI systems.We experimentally demonstrate that employing a scattering lens allows us to achieve relatively good phase information and robust 3D imaging from depth measurements,yielding measurement accuracy only marginally lower than that of a telecentric lens,typically within approximately 10μm.Furthermore,the scattering lens demonstrates robust performance even when the imaging distance exceeds the typical working distance of a telecentric lens.The proposed method facilitates the application of scattering imaging techniques,providing a more flexible solution for MSL3DI.
基金Project supported by the Inner Mongolia University of Science and Technology Basic Research Business Fee Project(2022QNJS068,2024QNJS132)Inner Mongolia Autonomous Region Scientific and Technological Achievements Transformation Project(CGZH2018153)+1 种基金Inner Mongolia Autonomous Region Science and Technology Innovation Guidance Incentive Fund(0406041703)Project of Natural Science Foundation of Inner Mongolia(2024SHZR2341)。
文摘The influence of the growth of rare earth on the viscosity during the uniform cooling of CaO-SiO_(2-)CaF_(2)-Ce_(2)O_(3)slag was investigated by the high temperature viscometer.The results show that Ce_(2)O_(3)affects the viscosity variedly before and after the break temperature.At higher temperatures Ce_(2)O_(3)reduces the viscosity.When the temperature is below the break temperature,at a Ce_(2)O_(3)content of≥3 mol%,a rareearth crystalline phase is observed during the slag cooling process,and the break temperature progressively increases with the increase of Ce_(2)O_(3)concentration.There are no crystallized rare earths in the slag under the condition of Ce_(2)O_(3)concentration lower than 3 mol%.Too low or too high CaF_(2)content is found to be unfavorable for rare-earth crystallisation.The increase of Ce_(2)O_(3)content facilitates the depolymerization of silica-oxygen tetrahedral structure.Ca-F bond exists between structural units,weakening the flow resistance of structural units and lowering the viscosity of slag.
基金Project supported by the National Natural Science Foundation of China(21101107,51173107)State Key Laboratory of Pollution Control and Resource Reuse Foundation(PCRRF19017)。
文摘Herein we report novel photocatalysts ZnIn_(2)S_(4)-Ag-LaFeO_(3) with the core-shell structured materials prepared by hydrothermal method.In order to improve the efficiency of photocatalytic degradation of pollutants,LaFeO_(3) was prepared by hydrothermal followed by calcination,and further Ag nanoparticle(NP)was loaded onto the spherical structure of LaFeO_(3) by photolysis of silver nitrate,and finally the spherical Znln_(2)S_(4)-Ag-LaFeO_(3) photocatalyst was prepared by hydrothermal method again.The structure and properties of the as-prepared materials were characterized by X-ray photoelectron spectroscopy,ultraviolet-visible absorption spectroscopy,X-ray diffraction,scanning electron microscopy and fluorescence spectra.The results show that the synthesized composite photocatalysts display a significant improvement in photocatalytic efficiency relative to the single LaFeO_(3) and ZnIn_(2)S_(4)and form a core-shell structure.Furthermore,the effect of the ratio of each component on the photocatalytic efficiency was investigated in detail,and it is discovered that at an Methylene Blue(MB)concentration of 0.219 mol/L,the degradation rate of MB is 95%at 120 min using 0.02 g of catalyst with an ideal ZnIn_(2)S_(4):Ag:LaFeO_(3)ratio of 10:0.5:1.The possible mechanisms to improve the photocatalytic efficiency were explored.
基金Project supported by National Research and Innovation Agency through Rumah Program Organisasi Riset Nanoteknologi dan Material Maj u(ORNM)2024Indonesia Ministry of Finance through the competitive research program of RISPRO Kompetisi(PRJ-68/LPDP/2023)。
文摘Structural modification of three dimensional(3D)materials for the application of dielectric loss-based microwave absorbing materials(MAMs)usually relies on intricate synthesis process and can pose challenges in terms of scalability and mass production for practical application.In this work,we reported a successful attempt in modifying the 3D structure of mesoporous lanthanum oxide(La_(2)O_(3))for effective broadband MAMs candidate via simple co-precipitation process.The inclusion of cetyltrimethylammonium bromide(CTAB)and hydrothermal aging treatment result in a significant transformation of La_(2)O_(3)particles from their original polygonal form to a 3D coral-like and nano needle-like structure.The utilization of CTAB and hydrothermal aging results in the increase of surface area and a two-fold increase in pore volume of the resulting La_(2)O_(3).Due to its unique 3D structure,the 3D coral-like and nano needle-like La_(2)O_(3)materials possess a broadband electromagnetic(EM)wave absorption characteristic with the effective absorption bandwidth(EAB)covering the C-band frequency range.Specifically,in the La_(2)O_(3)C-H sample(with CTAB-with hydrothermal),it exhibits strong EM wave absorption with a reflection loss(RL)value of-33.07 dB which equals to 99.95%EM wave absorption at a thickness of only 1.50 mm.The detailed analysis of EM wave absorption properties reveals that the improvement of La_(2)O_(3)materials to attenuate EM wave energy arises from the dielectric loss phenomenon,the enhanced interfacial polarization,multiple reflections mechanism,and conduction loss mechanism induced by the 3D structural formation of the La_(2)O_(3)structure.This work proposes a novel and efficient approach in synthesizing and modifying 3D materials for effective broadband EM wave absorption.
基金supported by the National Natural Science Foundation of China(No.52274294)the Fundamental Research Funds for the Central Universities,China(No.N2124007-1)the Fund of the State Key Laboratory of Solidification Processing in Northwestern Polytechnical University,China(No.SKLSP202101)。
文摘In response to the limitations of conventional chemical synthesis methods for the structural modulation of nanomaterials,an innovative high magnetic field-assisted wet chemical synthesis method was proposed to prepare NiFe_(2)O_(4)/Fe_(2)O_(3) heterostructures.It is found that the high-energy physical field could induce a more homogeneous morphology of NiFe_(2)O_(4)/Fe_(2)O_(3),accompanied by phase transformation from Fe_(2)O_(3) to NiFe_(2)O_(4).As a result,the optimized structure obtained under the magnetic field endows NiFe_(2)O_(4)/Fe_(2)O_(3) with enhanced performance for the lithium-ion battery anode,as evidenced by an increase of 16%(1200 mA·h/g)in discharge capacity and 24% in ultra-stable cycling performance(capacity retention of 97.1%).These results highlight the feasibility of high magnetic fields in modulating material structure and enhancing lithium storage performance.
基金supported by the National Natural Science Foundation of China(52301240,52472274)the Fundamental Research Funds for the Provincial Universities of Zhejiang(GK259909299001-022)。
文摘The magnetic refrigeration(MR)based on the principle of magnetocaloric effect(MCE)in magnetic materials was recognized as an alternative cooling way to our present commercialized vapor compression cycle technology.Evidently,a vital prerequisite for practical applications is the exploration of candidate materials with prominent magnetocaloric performances.In this paper,the polycrystalline garnet RE_(3)Al_(5)O_(12)(RE=Tb,Dy and Ho)compounds with the cubic structure(space group:Ia3d)were prepared using the Pechini sol-gel method,and their crystal structure,magnetic properties and comprehensive magnetocaloric performances were studied.The analysis of magnetic susceptibility curves in a static magnetic field H=0.1 T reveal that the Dy_(3)Al_(5)O_(12)undergoes antiferromagnetic transition with Néel temperature TN≈2.6 K,whereas the Tb_(3)Al_(5)O_(12)and Ho_(3)Al_(5)O_(12)exhibit no features indicative of the magnetic ordering processes down to 1.8 K.The comprehensive magnetocaloric performances,namely the maximum magnetic entropy change and relative cooling power,are derived indirectly from the isothermal field-dependent magnetization data,which yield 11.72,10.42,7.53 J/(kg·K)and 84.56,69.52,70.35 J/kg for the Tb_(3)Al_(5)O_(12),Dy_(3)Al_(5)O_(12)and Ho_(3)Al_(5)O_(12)under a low field change(ΔH)of 0-2 T,respectively.The superior comprehensive magnetocaloric performances and wide operating temperature range of these compounds under lowΔH make them attractive for cryogenic MR technology.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11847094,61764001,and U1404212)the Cheung Kong Scholars Programme of China+2 种基金the Program of Changjiang Scholars and Innovative Research Team in University,China(Grant No.IRT1132)Open Project of State Key Laboratory of Superhard Materials(Jilin University)China(Grant No.201703)
文摘Due to many remarkable physical and chemical properties,two-dimensional(2D)nanomaterials have become a hot spot in the field of condensed matter physics.In this paper,we have studied the structural,mechanical,and electronic properties of the 2D GaInO_(3)system by first-principles method.We find that 2D Ga InO_(3)can exist stably at ambient condition.Molecular dynamic simulations show that GaInO_(3)-sheet has excellent thermal stability and is stable up to1100 K.Electronic structural calculations show that GaInO_(3)-sheet has a band gap of 1.56 eV,which is close to the ideal band gap of solar cell materials,demonstrating great potential in future photovoltaic application.In addition,strain effect studies show that the GaInO_(3)-sheet structure always exhibits a direct band gap under biaxial compressive strain,and as the biaxial compressive strain increases,the band gap gradually decreases until it is converted into metal.While biaxial tensile strain can cause the 2D material to transform from a direct band gap semiconductor into an indirect band gap semiconductor,and even to metal.Our research expands the application of the Ga InO_(3)system,which may have potential application value in electronic devices and solar energy.
基金Projects(50934002,51074013,51304076,51104100)supported by the National Natural Science Foundation of ChinaProject(IRT0950)supported by the Program for Changjiang Scholars Innovative Research Team in Universities,ChinaProject(2012M510007)supported by China Postdoctoral Science Foundation
文摘Methods and procedures of three-dimensional （3D） characterization of the pore structure features in the packed ore particle bed are focused. X-ray computed tomography was applied to deriving the cross-sectional images of specimens with single particle size of 1-2, 2-3, 3-4, 4-5, 5-6, 6-7, 7-8, 8-9, 9-10 ram. Based on the in-house developed 3D image analysis programs using Matlab, the volume porosity, pore size distribution and degree of connectivity were calculated and analyzed in detail. The results indicate that the volume porosity, the mean diameter of pores and the effective pore size （d50） increase with the increasing of particle size. Lognormal distribution or Gauss distribution is mostly suitable to model the pore size distribution. The degree of connectivity investigated on the basis of cluster-labeling algorithm also increases with increasing the particle size approximately.
基金Project (51101022) supported by the National Natural Science Foundation of ChinaProject (CHD2012JC096) supported by the Fundamental Research Funds for the Central Universities,China
文摘The rapid solidification process of Mg7Zn3 alloy was simulated by the molecular dynamics method. The relationship between the local structure and the dynamics during the liquid-glass transition was deeply investigated. It was found that the Mg-centered FK polyhedron and the Zn-centered icosahedron play a critical role in the formation of Mg7Zn3 metallic glass. The self-diffusion coefficients of Mg and Zn atoms deviate from the Arrhenius law near the melting temperature and then satisfy the power law. According to the time correlation functions of mean-square displacement, incoherent intermediate scattering function and non-Gaussian parameter, it was found that the β-relaxation in Mg7Zn3 supercooled liquid becomes more and more evident with decreasing temperature, and the α-relaxation time rapidly increases in the VFT law. Moreover, the smaller Zn atom has a faster relaxation behavior than the Mg atom. Some local atomic structures with short-range order have lower mobility, and they play a critical role in the appearance of cage effect in theβ-relaxation regime. The dynamics deviates from the Arrhenius law just at the temperature as the number of local atomic structures begins to rapidly increase. The dynamic glass transition temperature （Tc） is close to the glass transition point in structure （TgStr）.
文摘The electronic structure,including band structure,density of states （DOS）, and partial density of states of SrTi1-xSbxO3 with x = 0,0. 125,0.25,and 0.33 is calculated from the first principles of plane wave ultra-soft pseudo-potential technology based on density function theory. The calculated results reveal that due to the electron doping,the Fermi level moves into the conduction bands for SrTi1-xSbxO3 with x = 0. 125 and the system shows metallic behavior. In addition, the DOS moves towards low energy and the optical band gap is broadened. The wide band gap and the low density of the states in the conduction band result in the transparency of the films.
