The short-range order structures of Fe_xGe_(1-x) amorphous thin films,(x=8.7,19.1 and 28.5%)have been studied by means of X-ray absorption spectrum.The nearest neighbors around a Ge or an Fe atom are constituted by tw...The short-range order structures of Fe_xGe_(1-x) amorphous thin films,(x=8.7,19.1 and 28.5%)have been studied by means of X-ray absorption spectrum.The nearest neighbors around a Ge or an Fe atom are constituted by two coordinate sub-shells with a very short dis- tance,In two films with lower Fe content,structural parameters of the nearest neighbors around a Ge atom are very near to that in amorphous germanium,and the positions of Fe at- oms are randomly substitutional.But when x=28.5%,some great changes occur on the short-range order structure of a-Fe_xGe_(1-x) film:its structure deviates from continuous ran- dora network and tends toward dense random packing of atoms.Meanwhile,there is a strong- er interaction between near neighboring Fe-Ge atoms in a-Fe_xGe_(1-x) films.展开更多
In an effort to clarify the formation mechanism of LPSO structure in Mg-Y-Zn alloy,the chemical environment and structural ordering in liquid Mg-rich Mg-Y-Zn system are investigated with the aid of ab-initio molecular...In an effort to clarify the formation mechanism of LPSO structure in Mg-Y-Zn alloy,the chemical environment and structural ordering in liquid Mg-rich Mg-Y-Zn system are investigated with the aid of ab-initio molecular dynamics simulation.In liquid Mg-rich Mg-Y alloys,the strong Mg-Y interaction is determined,which promotes the formation of fivefold symmetric local structure.For Mg-Zn alloys,the weak Mg-Zn interaction results in the fivefold symmetry weakening in the liquid structure.Due to the coexistence of Y and Zn,the strong attractive interaction is introduced in liquid Mg-Y-Zn ternary alloy,and contributes to the clustering of Mg,Y,Zn launched from Zn.What is more,the distribution of local structures becomes closer to that in pure Mg compared with that in binary Mg-Y and Mg-Zn alloys.These results should relate to the origins of the Y/Zn segregation zone and close-packed stacking mode in LPSO structure,which provides a new insight into the formation mechanism of LPSO structure at atomic level.展开更多
Magnesium alloys with a long-period stacking ordered(LPSO)structure usually possess excellent static strength,but their fatigue behaviors are poorly understood.This work presents the effect of the LPSO structure on th...Magnesium alloys with a long-period stacking ordered(LPSO)structure usually possess excellent static strength,but their fatigue behaviors are poorly understood.This work presents the effect of the LPSO structure on the crack behaviors of Mg alloys in a very high cycle fatigue(VHCF)regime.The LPSO lamellas lead to a facet-like cracking process along the basal planes at the crack initiation site and strongly prohibit the early crack propagation by deflecting the growth direction.The stress intensity factor at the periphery of the faceted area is much higher than the conventional LPSO-free Mg alloys,contributing higher fatigue crack propagation threshold of LPSO-containing Mg alloys.Microstructure observation at the facets reveals a layer of ultrafine grains at the fracture surface due to the cyclic contact of the crack surface,which supports the numerous cyclic pressing model describing the VHCF crack initiation behavior.展开更多
Lithium-sulfur batteries(LSBs)have drawn significant attention owing to their high theoretical discharge capacity and energy density.However,the dissolution of long-chain polysulfides into the electrolyte during the c...Lithium-sulfur batteries(LSBs)have drawn significant attention owing to their high theoretical discharge capacity and energy density.However,the dissolution of long-chain polysulfides into the electrolyte during the charge and discharge process(“shuttle effect”)results in fast capacity fading and inferior electrochemical performance.In this study,Mn_(2)O_(3)with an ordered mesoporous structure(OM-Mn_(2)O_(3))was designed as a cathode host for LSBs via KIT-6 hard templating,to effectively inhibit the polysulfide shuttle effect.OM-Mn_(2)O_(3)offers numerous pores to confine sulfur and tightly anchor the dissolved polysulfides through the combined effects of strong polar-polar interactions,polysulfides,and sulfur chain catenation.The OM-Mn_(2)O_(3)/S composite electrode delivered a discharge capacity of 561 mAh g-1 after 250 cycles at 0.5 C owing to the excellent performance of OM-Mn_(2)O_(3).Furthermore,it retained a discharge capacity of 628mA h g-1 even at a rate of 2 C,which was significantly higher than that of a pristine sulfur electrode(206mA h g-1).These findings provide a prospective strategy for designing cathode materials for high-performance LSBs.展开更多
It was revealed that an average energy of special boundaries is proportional to APB energy in the alloys with the L12 superstructure. This fact proves the appearance of the GAPBs in the planes of location of special b...It was revealed that an average energy of special boundaries is proportional to APB energy in the alloys with the L12 superstructure. This fact proves the appearance of the GAPBs in the planes of location of special boundaries in coincidence sites of ordered alloys. It was determined that the more energy of special boundaries in ordered alloys, the more energy of complex stacking fault. There is a correlation between the distribution of special boundaries as a function its relative energy and ordering energy: the more ordering energy, the more degree of washed away of distribution. The correlation between average relative energy of special boundaries and ordering energy was detected: the more ordering energy, the more average energy of special boundaries. The reverse dependence between ordering energy and average number of special boundaries in grains limited by boundaries of general type was discovered.展开更多
We measured the resonant Raman spectra of all-trans-β-carotene in solvents with different densities and concentrations at different temperatures. The results demonstrated that the Raman scattering cross section (RSC...We measured the resonant Raman spectra of all-trans-β-carotene in solvents with different densities and concentrations at different temperatures. The results demonstrated that the Raman scattering cross section (RSCS) of short-chain polymer all-trans-β-carotene is extremely high in liquid. Resonance and strong coherent weakly damped CC bond vibrating properties play important roles under these conditions. Coherent weakly damped CC bond vibration strength is associated with molecular ordered structure. All-trans-β-carotene has highly ordered structure and strong coherent weakly damped CC bond vibrating properties, which lead to large RSCS in the solvent with large density and low concentration at low temperature.展开更多
Sodium-ion hybrid capacitor(SIHC)is one of the most promising alternatives for large-scale energy storage due to its high energy and power densities,natural abundance,and low cost.However,overcoming the imbalance betw...Sodium-ion hybrid capacitor(SIHC)is one of the most promising alternatives for large-scale energy storage due to its high energy and power densities,natural abundance,and low cost.However,overcoming the imbalance between slow Na^(+)reaction kinetics of battery-type anodes and rapid ion adsorption/desorption of capacitive cathodes is a significant challenge.Here,we propose the high-rate-performance NiS_(2)@OMGC anode material composed of monodispersed NiS_(2) nanocrystals(8.8±1.7 nm in size)and N,S-co-doped graphenic carbon(GC).The NiS_(2)@OMGC material has a three-dimensionally ordered macroporous(3DOM)morphology,and numerous NiS_(2) nanocrystals are uniformly embedded in GC,forming a core-shell structure in the local area.Ultrafine NiS_(2) nanocrystals and their nano-microstructure demonstrate high pseudocapacitive Na-storage capability and thus excellent rate performance(355.7 mAh/g at 20.0 A/g).A SIHC device fabricated using NiS_(2)@OMGC and commercial activated carbon(AC)cathode exhibits ultrahigh energy densities(197.4 Wh/kg at 398.8 W/kg)and power densities(43.9 kW/kg at 41.3 Wh/kg),together with a long life span.This outcome exemplifies the rational architecture and composition design of this type of anode material.This strategy can be extended to the design and synthesis of a wide range of high-performance electrode materials for energy storage applications.展开更多
Currently,electromagnetic radiation and interference have a significant effect on the operation of electronic devices and human health systems.Thus,developing excellent microwave absorbers have a huge significance in ...Currently,electromagnetic radiation and interference have a significant effect on the operation of electronic devices and human health systems.Thus,developing excellent microwave absorbers have a huge significance in the material research field.Herein,a kind of ultrafine zinc oxide(ZnO)nanoparticles(NPs)supported on three-dimensional(3D)ordered mesoporous carbon spheres(ZnO/OMCS)is prepared from silica inverse opal by using phenolic resol precursor as carbon source.The prepared lightweight ZnO/OMCS nanocomposites exhibit 3D ordered carbon sphere array and highly dispersed ultrafine ZnO NPs on the mesoporous cell walls of carbon spheres.ZnO/OMCS-30 shows microwave absorbing ability with a strong absorption(−39.3 dB at 10.4 GHz with a small thickness of 2 mm)and a broad effective absorption bandwidth(9.1 GHz).The outstanding microwave absorbing ability benefits to the well-dispersed ultrafine ZnO NPs and the 3D ordered mesoporous carbon spheres structure.This work opened up a unique way for developing lightweight and high-efficient carbon-based microwave absorbing materials.展开更多
Highly ordered mesoporous NiMoO4 material was successfully synthesized using mesoporous silica KIT-6 as hard template via vacuum nanocasting method. The structure was characterized by means of XRD, TEM, N2 adsorption-...Highly ordered mesoporous NiMoO4 material was successfully synthesized using mesoporous silica KIT-6 as hard template via vacuum nanocasting method. The structure was characterized by means of XRD, TEM, N2 adsorption-desorption, Raman and FT-IR. The mesoporous NiMoO4 with the coexistence of a-NiMoO4 and fl-NiMoO4 showed well-ordered mesoporous structure, a bimodal pore size distribution and crystalline framework. The catalytic performance of NiMoOa was investigated for oxidative dehydrogenation of propane. It is demonstrated that the mesoporous NiMoO4 catalyst with more surface active oxygen species showed better catalytic performance in oxidative dehydrogena- tion of propane in comparison with bulk NiMoO4.展开更多
Simultaneously enhancing the reaction kinetics,mass transport,and gas release during alkaline hydrogen evolution reaction(HER)is critical to minimizing the reaction polarization resistance,but remains a big challenge....Simultaneously enhancing the reaction kinetics,mass transport,and gas release during alkaline hydrogen evolution reaction(HER)is critical to minimizing the reaction polarization resistance,but remains a big challenge.Through rational design of a hierarchical multiheterogeneous three-dimensionally(3D)ordered macroporous Mo_(2)C-embedded nitrogen-doped carbon with ultrafine Ru nanoclusters anchored on its surface(OMS Mo_(2)C/NC-Ru),we realize both electronic and morphologic engineering of the catalyst to maximize the electrocatalysis performance.The formed Ru-NC heterostructure shows regulative electronic states and optimized adsorption energy with the intermediate H*,and the Mo_(2)C-NC heterostructure accelerates the Volmer reaction due to the strong water dissociation ability as confirmed by theoretical calculations.Consequently,superior HER activity in alkaline solution with an extremely low overpotential of 15.5 mV at 10 mAcm^(−2)with the mass activity more than 17 times higher than that of the benchmark Pt/C,an ultrasmall Tafel slope of 22.7 mV dec−1,and excellent electrocatalytic durability were achieved,attributing to the enhanced mass transport and favorable gas release process endowed from the unique OMS Mo_(2)C/NC-Ru structure.By oxidizing OMS Mo_(2)C/NC-Ru into OMS MoO_(3)-RuO_(2)catalyst,it can also be applied as efficient oxygen evolution electrocatalyst,enabling the construction of a quasi-symmetric electrolyzer for overall water splitting.Such a device's performance surpassed the state-of-the-art Pt/C||RuO2 electrolyzer.This study provides instructive guidance for designing 3D-ordered macroporous multicomponent catalysts for efficient catalytic applications.展开更多
Formation of β’ phase in long-period stacking ordered(LPSO) structures in an Mg;Co;Y;(at.%) alloy after aging at 200 °C for 24 h or electron beam(EB) irradiation has been studied by high-angle annular dark-fiel...Formation of β’ phase in long-period stacking ordered(LPSO) structures in an Mg;Co;Y;(at.%) alloy after aging at 200 °C for 24 h or electron beam(EB) irradiation has been studied by high-angle annular dark-field scanning transmission electron microscopy(HAADFSTEM). β’ phase was precipitated only in the Mg matrix but not in LPSO structures after aging at 200 °C for 24 h. LPSO structure containing stacking defects transforms into the β’-long phase during EB irradiation, which plays a key role in accelerating solute atoms’ diffusion. New complex β’(LPSO) structures formed in the alloy after EB irradiation, such as β’(12 H) structure with an orthorhombic lattice(Mg;Y, Cmcm,a = 2 _(a0)= 0.642 nm, b=4√3_(a0), c = 6 _(c0)= 3.12 nm).展开更多
The structural model of sodium silicate glass plays a crucial role in understanding the properties and the nature of binary glass and other more complicated silicate glasses.This work proposes a structural model for s...The structural model of sodium silicate glass plays a crucial role in understanding the properties and the nature of binary glass and other more complicated silicate glasses.This work proposes a structural model for sodium silicate glass based on the medium-range ordering structure of silica glass and the information found from the Na_(2)O-SiO_(2) phase diagram.This new model is different from previous ones.First,the sodium silica glass is both structurally and chemically heterogeneous on the nanometer scale.Secondly,the sodium cation distribution is Na_(2)O concentration-dependent.In order to reflect the structural change with Na_(2)O concentration,it requires two different schematic graphs to present the glass structure.The model can be extended to other binary and multiple component silicate glasses and can be experimentally verified.展开更多
Anti-structured defects bridge atom migration among heterogeneous sublattices facilitating diffusion but could also result in the collapse of ordered structure.Component distribution Ni(75)AlxV(25-x) alloys are in...Anti-structured defects bridge atom migration among heterogeneous sublattices facilitating diffusion but could also result in the collapse of ordered structure.Component distribution Ni(75)AlxV(25-x) alloys are investigated using a microscopic phase field model to illuminate relations between anti-structured defects and composition,precipitate order,precipitate type,and phase stability.The Ni(75)AlxV(25-x) alloys undergo single Ni3V(stage Ⅰ),dual Ni3Al and Ni3V(stage Ⅱ with Ni3V prior;and stage Ⅲ with Ni3Al prior),and single Ni3Al(stage Ⅳ) with enhanced aluminum level.For Ni3V phase,anti-structured defects(V(Ni1),Niy,except V(Ni2)) and substitution defects(Al(Ni1),Al(Ni2),Alv) exhibit a positive correlation to aluminum in stage I,the positive trend becomes to negative correlation or smooth during stage Ⅱ.For Ni3 Al phase,anti-structured defects(Al(Ni),Ni(Al)) and substitution defects(V(Ni),V(Al)) have a positive correlation to aluminum in stage Ⅱ,but Ni(Al) goes down since stage Ⅲ and lasts to stage Ⅳ.V(Ni) and V(Al) fluctuate when Ni3Al precipitates prior,but go down drastically in stageⅣ.Precipitate type conversion of single Ni3V/dual(Ni3V+Ni3Al) affects Ni3V defects,while dual(Ni3V+Ni3Al)/single Ni3 Al has little effect on Ni3Al defects.Precipitate order swap occurred in the dual phase region affects on Ni3Al defects but not on Ni3V.展开更多
Herein,a series of three-dimensionally ordered macroporous(3DOM)Bi_(4)O_(5)Br_(2)photocatalysts with different macropore sizes were successfully fabricated via a polymethyl methacrylate(PMMA)template method.The photoc...Herein,a series of three-dimensionally ordered macroporous(3DOM)Bi_(4)O_(5)Br_(2)photocatalysts with different macropore sizes were successfully fabricated via a polymethyl methacrylate(PMMA)template method.The photocatalytic activity for phenol degradation over 3DOM Bi_(4)O_(5)Br_(2)first increased and then decreased with the rise in macropore size.Specifically,3DOM Bi_(4)O_(5)Br_(2)-255(macropore diameter ca.170 nm)exhibits the best photocatalytic activity in the static system,which is about 4.5,7.3,and 11.9 times higher than those of bulk Bi_(4)O_(5)Br_(2),Bi_(2)WO_(6),and g-C_(3)N_(4),respectively.Meanwhile,high phenol conversion(75%)is also obtained over 3DOM Bi_(4)O_(5)Br_(2)-255 in the flow system under full spectrum irradiation.Furthermore,3DOM Bi_(4)O_(5)Br_(2)-255 also shows strong mineralization capacity owing to the downward shift of valance band position(0.15 V)as compared with Bi_(4)O_(5)Br_(2).Total organic carbon(TOC)removal rate over 3DOM Bi_(4)O_(5)Br_(2)-255(62%)is much higher than that of Bi_(4)O_(5)Br_(2)(17%).The enhancement in photocatalytic performance of 3DOM Bi_(4)O_(5)Br_(2)-255 is attributable to its better phenol adsorption,O_(2)activation,and charge separation and transfer abilities.This work combines the advantages of 3D structure and surface dangling bonds,providing new possibilities for designing highly efficient photocatalysts for pollutants removal.展开更多
In this paper,a variety of solution concepts are trifled into an order structure framework,the concept of the order structure function(OSF) is presented,based on which, a now-type solution for MCDM-OSF-efficient solut...In this paper,a variety of solution concepts are trifled into an order structure framework,the concept of the order structure function(OSF) is presented,based on which, a now-type solution for MCDM-OSF-efficient solution or called in this study()-efficient solution,wed efficient solution and strong()-efficient solution,etc.,is proposed. It be been proved that the optimal solution of MCDM or MMP in verious senses,such as the Pareto efficient solution,G-efficient soluition,H-efficient solution,etc.,all can be considered as the special cases of the OSF-efficient solution for the special s and s.Finally,the application of the OSF-efficient solution is discussed.展开更多
The synthetic hydrogels with high water contents are promising for various applications,however,they usually exhibit low mechanical properties.In this work,inspired by the natural biological soft tissues,whose hierarc...The synthetic hydrogels with high water contents are promising for various applications,however,they usually exhibit low mechanical properties.In this work,inspired by the natural biological soft tissues,whose hierarchically ordered fibrous structures result in high strength and good flexibility,a flexible,high-strength,and versatile hydrogel with the fiberboard-and-mortar hierarchically ordered structure(HFMOS)is developed based on ultralong hydroxyapatite(HAP)nanowires and polyacrylic acid(PAA).The as-prepared HFMOS hydrogel has a high water content(~70 wt.%),dense structure,and excellent mechanical properties,and these properties are similar to those of the human cartilage and are superior to many hydrogels reported in the literature.The excellent mechanical properties of the HFMOS hydrogel originate from the combination of the fiberboard-and-mortar hierarchically ordered structure,reinforcement of ultralong HAP nanowires,strong interfacial strength,and multiple energy dissipation pathways.Moreover,thanks to the controllable components and injection procedure,the HFMOS hydrogel with a Janus structure is prepared for particular applications.The HFMOS hydrogel possesses abundant ordered water channels,and can be used for loading,release,and directed delivery of various functional substances.Thus,the as-prepared flexible,high-strength,and versatile HFMOS hydrogel possesses a great potential for various applications such as water purification,pollution treatment,biomedicine,nanofluidic devices,and high-performance structural materials.展开更多
Both the solid solution and precipitation are mainly strengthening mechanism for the magnesium-based alloys. A great number of alloying elements can be dissolved into the Mg matrix to form the solutes and precipitates...Both the solid solution and precipitation are mainly strengthening mechanism for the magnesium-based alloys. A great number of alloying elements can be dissolved into the Mg matrix to form the solutes and precipitates.Moreover, the type of precipitates varies with different alloying elements and heat treatments, which makes it quite difficult to understand the formation mechanism of the precipitates in Mg-based alloys in depth. Thus, it is very hard to give a systematical regularity in precipitation process for the Mg-based alloys. This review is mainly focused on the formation and microstructural evolution of the precipitates, as a hot topic for the past few years, including Guinier-Preston Zones, quasicrystals and long-period stacking ordered phases formed in a number of Mg-TM-RE alloy systems, where TM = Al, Zn, Zr and RE = Y,Gd, Hd, Ce and La.展开更多
Lithium-sulfur(Li-S)battery has attracted intensive attention in the realm of energy storage owing to its high theoretical capacity and energy density.However,the shuttle effect of soluble lithium polysulfides(LiPSs)b...Lithium-sulfur(Li-S)battery has attracted intensive attention in the realm of energy storage owing to its high theoretical capacity and energy density.However,the shuttle effect of soluble lithium polysulfides(LiPSs)between electrodes results in rapid capacity degradation.Herein,a strategy which combines the design of both chemical interaction and microstructure of interlayer was proposed to suppress the shuttle effect.The chemical interaction between different functionalized MOFs and LiPSs was systematically studied to find the best candidate.Furthermore,an interlayer with ordered structure was constructed via the layer-by-layer assembly of metal-organic frameworks(MOFs)on graphene(UiO-66-NH_(2)@graphene)to create sinuous channels which can better impede the diffusion process of LiPSs by the strong adsorption of MOF toward LiPSs.Consequently,in comparison to the battery with a bare separator,the ordered interlayer increased the initial discharge capacity of battery by 28.98%at 1.0 C and lowered the capacity decay rate remarkably from 0.10%to 0.067%per cycle,indicating that the design of chemical interaction and microstructure paves the way for high-performance Li-S batteries.展开更多
Molecular dynamics simulations of a coarse-grained bead-spring model of ring polymer brushes un- der compression are presented. Flexible polymer brushes are always disordered during compression, whereas semiflexible p...Molecular dynamics simulations of a coarse-grained bead-spring model of ring polymer brushes un- der compression are presented. Flexible polymer brushes are always disordered during compression, whereas semiflexible polymer brushes tend to be ordered under sufficiently strong compression. Fur- ther, the polymer monomer density of the semiflexible polymer brush is very high near the brush surface, inducing a peak value of the free energy near the surface. Therefore~ when nanoparticles are compressed in semifiexible ring polymer brushes, they tend to exhibit a closely packed single-layer structure between the brush surface and the impenetrable wall, and a quasi-two-dimensional ordered structure near the brush surface is formed under strong compression. These findings provide a new approach to designing responsive applications.展开更多
文摘The short-range order structures of Fe_xGe_(1-x) amorphous thin films,(x=8.7,19.1 and 28.5%)have been studied by means of X-ray absorption spectrum.The nearest neighbors around a Ge or an Fe atom are constituted by two coordinate sub-shells with a very short dis- tance,In two films with lower Fe content,structural parameters of the nearest neighbors around a Ge atom are very near to that in amorphous germanium,and the positions of Fe at- oms are randomly substitutional.But when x=28.5%,some great changes occur on the short-range order structure of a-Fe_xGe_(1-x) film:its structure deviates from continuous ran- dora network and tends toward dense random packing of atoms.Meanwhile,there is a strong- er interaction between near neighboring Fe-Ge atoms in a-Fe_xGe_(1-x) films.
基金supported by National Natural Science Foundation of China,China(No.51901117,51801116)Youth Innovation and Technology Support Program of Shandong Provincial Colleges and Universities,China(No.2020KJA002)+2 种基金Youth Fund of Shandong Academy of Sciences,China(2020QN0021)Innovation Pilot Project for Fusion of Science,Education and Industry(International Cooperation)from Qilu University of Technology(Shandong Academy of Sciences),China(No.2020KJC-GH03)Several Policies on Promoting Collaborative Innovation and Industrialization of Achievements in Universities and Research Institutes,China(No.2019GXRC030)。
文摘In an effort to clarify the formation mechanism of LPSO structure in Mg-Y-Zn alloy,the chemical environment and structural ordering in liquid Mg-rich Mg-Y-Zn system are investigated with the aid of ab-initio molecular dynamics simulation.In liquid Mg-rich Mg-Y alloys,the strong Mg-Y interaction is determined,which promotes the formation of fivefold symmetric local structure.For Mg-Zn alloys,the weak Mg-Zn interaction results in the fivefold symmetry weakening in the liquid structure.Due to the coexistence of Y and Zn,the strong attractive interaction is introduced in liquid Mg-Y-Zn ternary alloy,and contributes to the clustering of Mg,Y,Zn launched from Zn.What is more,the distribution of local structures becomes closer to that in pure Mg compared with that in binary Mg-Y and Mg-Zn alloys.These results should relate to the origins of the Y/Zn segregation zone and close-packed stacking mode in LPSO structure,which provides a new insight into the formation mechanism of LPSO structure at atomic level.
基金The authors gratefully acknowledge the financial support from the National Natural Science Foundation of China(Nos.12072212 and 11832007)the National Key Research and Development Program of China(No.2018YFE0307104)the Applied Basic Research Programs of Sichuan Province(No.2021YJ0071).We also highly appreciate the help of Dr.Yan Li from the Department of Mechanics,Sichuan University.
文摘Magnesium alloys with a long-period stacking ordered(LPSO)structure usually possess excellent static strength,but their fatigue behaviors are poorly understood.This work presents the effect of the LPSO structure on the crack behaviors of Mg alloys in a very high cycle fatigue(VHCF)regime.The LPSO lamellas lead to a facet-like cracking process along the basal planes at the crack initiation site and strongly prohibit the early crack propagation by deflecting the growth direction.The stress intensity factor at the periphery of the faceted area is much higher than the conventional LPSO-free Mg alloys,contributing higher fatigue crack propagation threshold of LPSO-containing Mg alloys.Microstructure observation at the facets reveals a layer of ultrafine grains at the fracture surface due to the cyclic contact of the crack surface,which supports the numerous cyclic pressing model describing the VHCF crack initiation behavior.
基金Ministry of Trade,Industry and Energy,Grant/Award Number:20010095Korea Evaluation Institute of Industrial Technology,Grant/Award Number:20012341。
文摘Lithium-sulfur batteries(LSBs)have drawn significant attention owing to their high theoretical discharge capacity and energy density.However,the dissolution of long-chain polysulfides into the electrolyte during the charge and discharge process(“shuttle effect”)results in fast capacity fading and inferior electrochemical performance.In this study,Mn_(2)O_(3)with an ordered mesoporous structure(OM-Mn_(2)O_(3))was designed as a cathode host for LSBs via KIT-6 hard templating,to effectively inhibit the polysulfide shuttle effect.OM-Mn_(2)O_(3)offers numerous pores to confine sulfur and tightly anchor the dissolved polysulfides through the combined effects of strong polar-polar interactions,polysulfides,and sulfur chain catenation.The OM-Mn_(2)O_(3)/S composite electrode delivered a discharge capacity of 561 mAh g-1 after 250 cycles at 0.5 C owing to the excellent performance of OM-Mn_(2)O_(3).Furthermore,it retained a discharge capacity of 628mA h g-1 even at a rate of 2 C,which was significantly higher than that of a pristine sulfur electrode(206mA h g-1).These findings provide a prospective strategy for designing cathode materials for high-performance LSBs.
基金B.V.Konovalova., N.A. Koneva and E.V.Kozlov acknowledge the INTAS for the partial support of this research under INTAS97-319
文摘It was revealed that an average energy of special boundaries is proportional to APB energy in the alloys with the L12 superstructure. This fact proves the appearance of the GAPBs in the planes of location of special boundaries in coincidence sites of ordered alloys. It was determined that the more energy of special boundaries in ordered alloys, the more energy of complex stacking fault. There is a correlation between the distribution of special boundaries as a function its relative energy and ordering energy: the more ordering energy, the more degree of washed away of distribution. The correlation between average relative energy of special boundaries and ordering energy was detected: the more ordering energy, the more average energy of special boundaries. The reverse dependence between ordering energy and average number of special boundaries in grains limited by boundaries of general type was discovered.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10774057 and 10974067)the Graduate Innovation Fund of Jilin University,China (Grant No. 20101046)
文摘We measured the resonant Raman spectra of all-trans-β-carotene in solvents with different densities and concentrations at different temperatures. The results demonstrated that the Raman scattering cross section (RSCS) of short-chain polymer all-trans-β-carotene is extremely high in liquid. Resonance and strong coherent weakly damped CC bond vibrating properties play important roles under these conditions. Coherent weakly damped CC bond vibration strength is associated with molecular ordered structure. All-trans-β-carotene has highly ordered structure and strong coherent weakly damped CC bond vibrating properties, which lead to large RSCS in the solvent with large density and low concentration at low temperature.
基金supported by the National Natural Science Foundation of Tianjin(No.20JCQNJC01280)the National Natural Science Foundation of China(No.21905201)+1 种基金the support of the scientifi c research project from China Three Gorges Corporation(No.202103406)supported by Tohoku University and JSPS KAKENHI(No.JP16J06828).
文摘Sodium-ion hybrid capacitor(SIHC)is one of the most promising alternatives for large-scale energy storage due to its high energy and power densities,natural abundance,and low cost.However,overcoming the imbalance between slow Na^(+)reaction kinetics of battery-type anodes and rapid ion adsorption/desorption of capacitive cathodes is a significant challenge.Here,we propose the high-rate-performance NiS_(2)@OMGC anode material composed of monodispersed NiS_(2) nanocrystals(8.8±1.7 nm in size)and N,S-co-doped graphenic carbon(GC).The NiS_(2)@OMGC material has a three-dimensionally ordered macroporous(3DOM)morphology,and numerous NiS_(2) nanocrystals are uniformly embedded in GC,forming a core-shell structure in the local area.Ultrafine NiS_(2) nanocrystals and their nano-microstructure demonstrate high pseudocapacitive Na-storage capability and thus excellent rate performance(355.7 mAh/g at 20.0 A/g).A SIHC device fabricated using NiS_(2)@OMGC and commercial activated carbon(AC)cathode exhibits ultrahigh energy densities(197.4 Wh/kg at 398.8 W/kg)and power densities(43.9 kW/kg at 41.3 Wh/kg),together with a long life span.This outcome exemplifies the rational architecture and composition design of this type of anode material.This strategy can be extended to the design and synthesis of a wide range of high-performance electrode materials for energy storage applications.
基金The authors are grateful of the financial support by the National Natural Science Foundation of China(51902083 and 21606068)the Foundation Strengthening Program(2019-JCJQ-142-00)the Higher Education Science and Technology Research Project of Hebei Province(ZD2019087).
文摘Currently,electromagnetic radiation and interference have a significant effect on the operation of electronic devices and human health systems.Thus,developing excellent microwave absorbers have a huge significance in the material research field.Herein,a kind of ultrafine zinc oxide(ZnO)nanoparticles(NPs)supported on three-dimensional(3D)ordered mesoporous carbon spheres(ZnO/OMCS)is prepared from silica inverse opal by using phenolic resol precursor as carbon source.The prepared lightweight ZnO/OMCS nanocomposites exhibit 3D ordered carbon sphere array and highly dispersed ultrafine ZnO NPs on the mesoporous cell walls of carbon spheres.ZnO/OMCS-30 shows microwave absorbing ability with a strong absorption(−39.3 dB at 10.4 GHz with a small thickness of 2 mm)and a broad effective absorption bandwidth(9.1 GHz).The outstanding microwave absorbing ability benefits to the well-dispersed ultrafine ZnO NPs and the 3D ordered mesoporous carbon spheres structure.This work opened up a unique way for developing lightweight and high-efficient carbon-based microwave absorbing materials.
基金supported by NSFC(21073235,21173270,21177160,21376261)863 Program(2013AA065302)PetroChina Innovation Foundation(2011D-5006-0403)
文摘Highly ordered mesoporous NiMoO4 material was successfully synthesized using mesoporous silica KIT-6 as hard template via vacuum nanocasting method. The structure was characterized by means of XRD, TEM, N2 adsorption-desorption, Raman and FT-IR. The mesoporous NiMoO4 with the coexistence of a-NiMoO4 and fl-NiMoO4 showed well-ordered mesoporous structure, a bimodal pore size distribution and crystalline framework. The catalytic performance of NiMoOa was investigated for oxidative dehydrogenation of propane. It is demonstrated that the mesoporous NiMoO4 catalyst with more surface active oxygen species showed better catalytic performance in oxidative dehydrogena- tion of propane in comparison with bulk NiMoO4.
基金University of Macao,Grant/Award Numbers:MYRG2018-00192-IAPME,MYRG2020-00187-IAPMEScience and Technology Development Fund,Macao SAR,Grant/Award Numbers:0021/2019/AIR,0041/2019/A1,0046/2019/AFJ,0191/2017/A3UEA funding。
文摘Simultaneously enhancing the reaction kinetics,mass transport,and gas release during alkaline hydrogen evolution reaction(HER)is critical to minimizing the reaction polarization resistance,but remains a big challenge.Through rational design of a hierarchical multiheterogeneous three-dimensionally(3D)ordered macroporous Mo_(2)C-embedded nitrogen-doped carbon with ultrafine Ru nanoclusters anchored on its surface(OMS Mo_(2)C/NC-Ru),we realize both electronic and morphologic engineering of the catalyst to maximize the electrocatalysis performance.The formed Ru-NC heterostructure shows regulative electronic states and optimized adsorption energy with the intermediate H*,and the Mo_(2)C-NC heterostructure accelerates the Volmer reaction due to the strong water dissociation ability as confirmed by theoretical calculations.Consequently,superior HER activity in alkaline solution with an extremely low overpotential of 15.5 mV at 10 mAcm^(−2)with the mass activity more than 17 times higher than that of the benchmark Pt/C,an ultrasmall Tafel slope of 22.7 mV dec−1,and excellent electrocatalytic durability were achieved,attributing to the enhanced mass transport and favorable gas release process endowed from the unique OMS Mo_(2)C/NC-Ru structure.By oxidizing OMS Mo_(2)C/NC-Ru into OMS MoO_(3)-RuO_(2)catalyst,it can also be applied as efficient oxygen evolution electrocatalyst,enabling the construction of a quasi-symmetric electrolyzer for overall water splitting.Such a device's performance surpassed the state-of-the-art Pt/C||RuO2 electrolyzer.This study provides instructive guidance for designing 3D-ordered macroporous multicomponent catalysts for efficient catalytic applications.
基金supported by the National Natural Science Foundation of China(Grant No.51801214 and 51871222)。
文摘Formation of β’ phase in long-period stacking ordered(LPSO) structures in an Mg;Co;Y;(at.%) alloy after aging at 200 °C for 24 h or electron beam(EB) irradiation has been studied by high-angle annular dark-field scanning transmission electron microscopy(HAADFSTEM). β’ phase was precipitated only in the Mg matrix but not in LPSO structures after aging at 200 °C for 24 h. LPSO structure containing stacking defects transforms into the β’-long phase during EB irradiation, which plays a key role in accelerating solute atoms’ diffusion. New complex β’(LPSO) structures formed in the alloy after EB irradiation, such as β’(12 H) structure with an orthorhombic lattice(Mg;Y, Cmcm,a = 2 _(a0)= 0.642 nm, b=4√3_(a0), c = 6 _(c0)= 3.12 nm).
基金the Office of Science,Office of Basic Energy Sciences,of the U.S.Department of Energy under Contract No.DE-AC02-05CH11231.
文摘The structural model of sodium silicate glass plays a crucial role in understanding the properties and the nature of binary glass and other more complicated silicate glasses.This work proposes a structural model for sodium silicate glass based on the medium-range ordering structure of silica glass and the information found from the Na_(2)O-SiO_(2) phase diagram.This new model is different from previous ones.First,the sodium silica glass is both structurally and chemically heterogeneous on the nanometer scale.Secondly,the sodium cation distribution is Na_(2)O concentration-dependent.In order to reflect the structural change with Na_(2)O concentration,it requires two different schematic graphs to present the glass structure.The model can be extended to other binary and multiple component silicate glasses and can be experimentally verified.
基金Project supported by the Natural Science Basic Research Plan in Shaanxi Province of China(Grant No.2016JQ5014)the Fundamental Research Funds for the Central Universities,China(Grant No.3102014JCQ01024)+2 种基金the Research Fund of the State Key Laboratory of Solidification Processing(NWPU),China(Grant No.114-QP-2014)the Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant No.20136102120021)the National Natural Science Foundation of China(Grant Nos.51474716 and 51475378)
文摘Anti-structured defects bridge atom migration among heterogeneous sublattices facilitating diffusion but could also result in the collapse of ordered structure.Component distribution Ni(75)AlxV(25-x) alloys are investigated using a microscopic phase field model to illuminate relations between anti-structured defects and composition,precipitate order,precipitate type,and phase stability.The Ni(75)AlxV(25-x) alloys undergo single Ni3V(stage Ⅰ),dual Ni3Al and Ni3V(stage Ⅱ with Ni3V prior;and stage Ⅲ with Ni3Al prior),and single Ni3Al(stage Ⅳ) with enhanced aluminum level.For Ni3V phase,anti-structured defects(V(Ni1),Niy,except V(Ni2)) and substitution defects(Al(Ni1),Al(Ni2),Alv) exhibit a positive correlation to aluminum in stage I,the positive trend becomes to negative correlation or smooth during stage Ⅱ.For Ni3 Al phase,anti-structured defects(Al(Ni),Ni(Al)) and substitution defects(V(Ni),V(Al)) have a positive correlation to aluminum in stage Ⅱ,but Ni(Al) goes down since stage Ⅲ and lasts to stage Ⅳ.V(Ni) and V(Al) fluctuate when Ni3Al precipitates prior,but go down drastically in stageⅣ.Precipitate type conversion of single Ni3V/dual(Ni3V+Ni3Al) affects Ni3V defects,while dual(Ni3V+Ni3Al)/single Ni3 Al has little effect on Ni3Al defects.Precipitate order swap occurred in the dual phase region affects on Ni3Al defects but not on Ni3V.
基金This work was supported by the National Natural Science Foundation of China(Nos.22206102,21872077,and 21621003)the National Key Research and Development Program of China(No.2020YFA0710304)the China Postdoctoral Science Foundation(No.2021M700078).
文摘Herein,a series of three-dimensionally ordered macroporous(3DOM)Bi_(4)O_(5)Br_(2)photocatalysts with different macropore sizes were successfully fabricated via a polymethyl methacrylate(PMMA)template method.The photocatalytic activity for phenol degradation over 3DOM Bi_(4)O_(5)Br_(2)first increased and then decreased with the rise in macropore size.Specifically,3DOM Bi_(4)O_(5)Br_(2)-255(macropore diameter ca.170 nm)exhibits the best photocatalytic activity in the static system,which is about 4.5,7.3,and 11.9 times higher than those of bulk Bi_(4)O_(5)Br_(2),Bi_(2)WO_(6),and g-C_(3)N_(4),respectively.Meanwhile,high phenol conversion(75%)is also obtained over 3DOM Bi_(4)O_(5)Br_(2)-255 in the flow system under full spectrum irradiation.Furthermore,3DOM Bi_(4)O_(5)Br_(2)-255 also shows strong mineralization capacity owing to the downward shift of valance band position(0.15 V)as compared with Bi_(4)O_(5)Br_(2).Total organic carbon(TOC)removal rate over 3DOM Bi_(4)O_(5)Br_(2)-255(62%)is much higher than that of Bi_(4)O_(5)Br_(2)(17%).The enhancement in photocatalytic performance of 3DOM Bi_(4)O_(5)Br_(2)-255 is attributable to its better phenol adsorption,O_(2)activation,and charge separation and transfer abilities.This work combines the advantages of 3D structure and surface dangling bonds,providing new possibilities for designing highly efficient photocatalysts for pollutants removal.
文摘In this paper,a variety of solution concepts are trifled into an order structure framework,the concept of the order structure function(OSF) is presented,based on which, a now-type solution for MCDM-OSF-efficient solution or called in this study()-efficient solution,wed efficient solution and strong()-efficient solution,etc.,is proposed. It be been proved that the optimal solution of MCDM or MMP in verious senses,such as the Pareto efficient solution,G-efficient soluition,H-efficient solution,etc.,all can be considered as the special cases of the OSF-efficient solution for the special s and s.Finally,the application of the OSF-efficient solution is discussed.
基金This work was financially supported by the National Natural Science Foundation of China(No.21875277).
文摘The synthetic hydrogels with high water contents are promising for various applications,however,they usually exhibit low mechanical properties.In this work,inspired by the natural biological soft tissues,whose hierarchically ordered fibrous structures result in high strength and good flexibility,a flexible,high-strength,and versatile hydrogel with the fiberboard-and-mortar hierarchically ordered structure(HFMOS)is developed based on ultralong hydroxyapatite(HAP)nanowires and polyacrylic acid(PAA).The as-prepared HFMOS hydrogel has a high water content(~70 wt.%),dense structure,and excellent mechanical properties,and these properties are similar to those of the human cartilage and are superior to many hydrogels reported in the literature.The excellent mechanical properties of the HFMOS hydrogel originate from the combination of the fiberboard-and-mortar hierarchically ordered structure,reinforcement of ultralong HAP nanowires,strong interfacial strength,and multiple energy dissipation pathways.Moreover,thanks to the controllable components and injection procedure,the HFMOS hydrogel with a Janus structure is prepared for particular applications.The HFMOS hydrogel possesses abundant ordered water channels,and can be used for loading,release,and directed delivery of various functional substances.Thus,the as-prepared flexible,high-strength,and versatile HFMOS hydrogel possesses a great potential for various applications such as water purification,pollution treatment,biomedicine,nanofluidic devices,and high-performance structural materials.
基金supported by National Natural Science Fundation of China (Nos. 51171192 and51271183)National Basic Research Program of China(No. 2013CB632205)Innovation Fund of Institute of Metal Research (IMR), Chinese Academy of Sciences(CAS)
文摘Both the solid solution and precipitation are mainly strengthening mechanism for the magnesium-based alloys. A great number of alloying elements can be dissolved into the Mg matrix to form the solutes and precipitates.Moreover, the type of precipitates varies with different alloying elements and heat treatments, which makes it quite difficult to understand the formation mechanism of the precipitates in Mg-based alloys in depth. Thus, it is very hard to give a systematical regularity in precipitation process for the Mg-based alloys. This review is mainly focused on the formation and microstructural evolution of the precipitates, as a hot topic for the past few years, including Guinier-Preston Zones, quasicrystals and long-period stacking ordered phases formed in a number of Mg-TM-RE alloy systems, where TM = Al, Zn, Zr and RE = Y,Gd, Hd, Ce and La.
基金The authors gratefully acknowledge financial support from the National Natural Science Foundation of China(Nos.51920105004 and 51902060)the Foundation for Young Talents in Higher Education of Guangdong,China(No.2018KQNCX065)National Natural Science Foundation of Guangdong,China(No.2019A1515010842).
文摘Lithium-sulfur(Li-S)battery has attracted intensive attention in the realm of energy storage owing to its high theoretical capacity and energy density.However,the shuttle effect of soluble lithium polysulfides(LiPSs)between electrodes results in rapid capacity degradation.Herein,a strategy which combines the design of both chemical interaction and microstructure of interlayer was proposed to suppress the shuttle effect.The chemical interaction between different functionalized MOFs and LiPSs was systematically studied to find the best candidate.Furthermore,an interlayer with ordered structure was constructed via the layer-by-layer assembly of metal-organic frameworks(MOFs)on graphene(UiO-66-NH_(2)@graphene)to create sinuous channels which can better impede the diffusion process of LiPSs by the strong adsorption of MOF toward LiPSs.Consequently,in comparison to the battery with a bare separator,the ordered interlayer increased the initial discharge capacity of battery by 28.98%at 1.0 C and lowered the capacity decay rate remarkably from 0.10%to 0.067%per cycle,indicating that the design of chemical interaction and microstructure paves the way for high-performance Li-S batteries.
文摘Molecular dynamics simulations of a coarse-grained bead-spring model of ring polymer brushes un- der compression are presented. Flexible polymer brushes are always disordered during compression, whereas semiflexible polymer brushes tend to be ordered under sufficiently strong compression. Fur- ther, the polymer monomer density of the semiflexible polymer brush is very high near the brush surface, inducing a peak value of the free energy near the surface. Therefore~ when nanoparticles are compressed in semifiexible ring polymer brushes, they tend to exhibit a closely packed single-layer structure between the brush surface and the impenetrable wall, and a quasi-two-dimensional ordered structure near the brush surface is formed under strong compression. These findings provide a new approach to designing responsive applications.