Significant two-way shape memory effect(TWSME)was achieved in single crystals of single-phase multielement Ni42-x Cu8 Cox Mn37 Ga13(8≤x≤12)alloys by performing thermomechanical training.However,anomalous dependence ...Significant two-way shape memory effect(TWSME)was achieved in single crystals of single-phase multielement Ni42-x Cu8 Cox Mn37 Ga13(8≤x≤12)alloys by performing thermomechanical training.However,anomalous dependence of the martensitic transformation temperature span on Co content was observed.Before training,quite a narrow temperature span of the martensitic transformation,nearly independent of the Co content,was observed in all single crystals.After training the temperature span was still narrow for 8≤x≤10.9 but was obviously expanded for 10.9<x≤12.High-resolution transmission electron microscopy revealed that at the atomic scale,there exists incommensurate modulated structure in the single phase single crystals,as evidenced by nonperiodic satellite spots in the selected area electronic diffraction patterns.Moreover,the modulated wave vector of the satellite spots was increased by higher Co contents.Combining first principal calculations it was considered that the incommensurate modulated structure originates from the formation of Co-Co pairs.After training arrays of ordered dislocations with the same Burgers vector were introduced for 8≤x≤10.9 but the network of dislocations was formed for 10.9<x≤12.Based on analysis of transmission electron microscopy,geometric phase,thermodynamics,and Landau theory,it was considered that the austenite/martensite phase interface was pinned by the network of dislocations,expanding the temperature span of the martensitic transformation.This work supplies new insights for understanding the microstructure and martensitic transformation of Ni-Mn-Ga-based alloys.展开更多
The Nd Fe B/Co multilayer films were prepared by magnetron sputtering. After that, the samples were annealed at 600 ℃ for 20 min. The surface morphology, phase structures and magnetic properties of Mo（50 nm）/[Nd F...The Nd Fe B/Co multilayer films were prepared by magnetron sputtering. After that, the samples were annealed at 600 ℃ for 20 min. The surface morphology, phase structures and magnetic properties of Mo（50 nm）/[Nd Fe B（100 nm）/Co（y）]×10/Mo（50 nm） thin films were researched by AFM, XRD and VSM, respectively. The results show that the films show stronger perpendicular magnetic anisotropy. When the thickness of Co layers is 10 nm, the coercivity Hc⊥ is the maximum, 295 k A/m. However, for y=10-20, the reduced remanence M/Ms of films has increased. When the thickness of Co layers is 20-30 nm, the Nd Fe B/Co multilayer films obtained more superior magnetic properties with M/Ms =0.95.展开更多
1.IntroductionSince the theory of spinodal decompo-sition in a supersaturated solid solution wasformulated by Hillert[1]and Cahn[2],thephenomena of spinodal decomposition havebeen found in many alloys.Tamura[3]haspoin...1.IntroductionSince the theory of spinodal decompo-sition in a supersaturated solid solution wasformulated by Hillert[1]and Cahn[2],thephenomena of spinodal decomposition havebeen found in many alloys.Tamura[3]haspointed out that spinodal decompositioncould also occur in maraging steels.A mod-ulated structure in 8Ni maraging steel was展开更多
A series of perovskite compounds of La1-x-yCaxKyMnO3 was prepared by hydrothermal disproportionation reaction of MnO2. The three oxidation states of manganese（Mn3＋, Mn4＋ and Mn5＋） can stably exist in the compound...A series of perovskite compounds of La1-x-yCaxKyMnO3 was prepared by hydrothermal disproportionation reaction of MnO2. The three oxidation states of manganese（Mn3＋, Mn4＋ and Mn5＋） can stably exist in the compounds. Under room temperature conditions, twice and three times modulated structure produced by the charge ordering can be observed by X-ray diffraction（XRD）, select area electron diffraction（SAED） and high resolution transmission electron microscopy（HR-TEM）. The splits of the diffraction peaks of the single crystals confirmed by synchrotron X-ray diffraction experiment are in accordance with those of the powder sample. The existence of the different oxidation states of Mn3＋, Mn4＋ and Mn5＋ can be considered to be the dominating reason of the complicated room temperature modulated structure.展开更多
Efficient energy storage devices with suitable electrode materials,that integrate high power and high energy,are the crucial requisites of the renewable power source,which have unwrapped new possibilities in the susta...Efficient energy storage devices with suitable electrode materials,that integrate high power and high energy,are the crucial requisites of the renewable power source,which have unwrapped new possibilities in the sustainable development of energy and the environment.Herein,a facile collagen microstructure modulation strategy is proposed to construct a nitrogen/oxygen dual-doped hierarchically porous carbon fiber with ultrahigh specific surface area(2788 m^(2)g^(-1))and large pore volume(4.56 cm^(3)g^(-1))via local microfibrous breakage/disassembly of natural structured proteins.Combining operando spectroscopy and density functional theory unveil that the dual-heteroatom doping could effectively regulate the electronic structure of carbon atom framework with enhanced electric conductivity and electronegativity as well as decreased diffusion resistance in favor of rapid pseudocapacitive-dominated Li^(+)-storage(353 mAh g^(-1)at 10 A g^(-1)).Theoretical calculations reveal that the tailored micro-/mesoporous structures favor the rapid charge transfer and ion storage,synergistically realizing high capacity and superior rate performance for NPCF-H cathode(75.0 mAh g^(-1)at 30 A g^(-1)).The assembled device with NPCF-H as both anode and cathode achieves extremely high energy density(200 Wh kg^(-1))with maximum power density(42600 W kg^(-1))and ultralong lifespan(80%capacity retention over 10000 cycles).展开更多
Single-atom catalysts are promising for H_(2)O_(2) photosynthesis from O_(2) and H_(2)O,but their efficiency is still limited by the ill-defined electronic structure.In this study,Co single-atoms with unique four plan...Single-atom catalysts are promising for H_(2)O_(2) photosynthesis from O_(2) and H_(2)O,but their efficiency is still limited by the ill-defined electronic structure.In this study,Co single-atoms with unique four planar N-coordination and one axial P-coordination(Co-N_(4)P_(1))are decorated on the lateral edges of nanorod-like crystalline g-C_(3)N_(4)(CCN)photocatalysts.Significantly,the electronic structures of central Co as active sites for O_(2) reduction reaction(ORR)and planar N-coordinator as active sites for H_(2)O oxidation reaction(WOR)in Co-N_(4)P_(1) can be well regulated by the synergetic effects of introducing axial P-coordinator,in contrast to the decorated Co single-atoms with only four planar N-coordination(Co-N_(4)).Specifically,directional photoelectron accumulation at central Co active sites,induced by an introduced midgap level in Co-N_(4)P_(1),mediates the ORR active sites from 4e–-ORR-selective terminal–NH_(2) sites to 2e–-ORR-selective Co sites,moreover,an elevated d-band center of Co 3d orbital strengthens ORR intermediate*OOH adsorption,thus jointly facilitating a highly selective and active 2e^(–)-ORR pathway to H_(2)O_(2) photosynthesis.Simultaneously,a downshifted p-band center of N_(2)p orbital in Co-N_(4)P_(1) weakens WOR intermediate*OH adsorption,thus enabling a preferable 2e^(–)-WOR pathway toward H_(2)O_(2) photosynthesis.Subsequently,Co-N_(4)P_(1) exhibits exceptional H_(2)O_(2) photosynthesis efficiency,reaching 295.6μmol g^(-1) h^(-1) with a remarkable solar-to-chemical conversion efficiency of 0.32%,which is 15 times that of Co-N_(4)(19.2μmol g^(-1) h^(-1))and 10 times higher than CCN(27.6μmol g^(-1) h^(-1)).This electronic structure modulation on single-atom catalysts offers a promising strategy for boosting the activity and selectivity of H_(2)O_(2) photosynthesis.展开更多
The sluggish electrochemical catalytic activity of the graphite felt electrodes for anode reaction is still a barrier for achieving high-performance vanadium redox flow battery(VRFB).It is significant to leverage the ...The sluggish electrochemical catalytic activity of the graphite felt electrodes for anode reaction is still a barrier for achieving high-performance vanadium redox flow battery(VRFB).It is significant to leverage the exceptional conductivity,excellent electrocatalytic activity,and structural tunability of MXene to address this issue.Herein,this work introduces nitrogen atoms to modulate the carbon layer structure of Ti_(3)C_(2)T_(x)MXene,inducing a reconfiguration of the local electronic structure,which enhances the anode interface activity and thereby improves the performance of VRFB.Ti_(3)C_(2)T_(x)exhibits high conductivity,excellent hydrophilicity,and a large specific surface area,providing excellent interface characteristics for V^(3+)/V^(2+)redox reaction.Moreover,interlayer treatment to modulate the mesoporous structure of MXene further increases the reactive surface area.Importantly,doping nitrogen atoms at carbon layer induces lattice distortions in Ti_(3)C_(2)T_(x),which enhances the charge transfer processes of the V^(3+)/V^(2+)redox reaction.The catalysis mechanism is also validated through density functional theory.Furthermore,the modified graphite felt electrode,as the anode of VRFB,relieves a higher energy efficiency of 68%at 250 mA cm^(-2),while the pristine electrode cannot operate at this current density.In addition,at 150 mA cm^(-2),the modified battery maintains energy efficiency at 75%without degradation after 500 cycles.This study utilizes rational atomic-level engineering for effective structural modulation to significantly enhance the catalytic activity of electrode reaction,offering a unique perspective for developing high-performance MXene electrocatalysts of VRFB.展开更多
Metal Fe/Pd compositionally modulated films(CMFs) were prepared by vapour depo- sition from two sources onto glass substrate under vacuum.The modulation and crystal structures of the films were examined by X-ray diffr...Metal Fe/Pd compositionally modulated films(CMFs) were prepared by vapour depo- sition from two sources onto glass substrate under vacuum.The modulation and crystal structures of the films were examined by X-ray diffraction.The magnetic properties were determined by vibrating sample magnetometer.The Pd layers in the Fe/Pd CMFs are of fcc structure,and the Fe layer structure transits from bcc into amorphous,state with decreasing thickness of Fe layer.The dependence of specific saturation magnetization on thickness of Fe layers has also been discussed.展开更多
The laminated transition metal disulfides(TMDs),which are well known as typical two-dimensional(2D)semiconductive materials,possess a unique layered structure,leading to their wide-spread applications in various field...The laminated transition metal disulfides(TMDs),which are well known as typical two-dimensional(2D)semiconductive materials,possess a unique layered structure,leading to their wide-spread applications in various fields,such as catalysis,energy storage,sensing,etc.In recent years,a lot of research work on TMDs based functional materials in the fields of electromagnetic wave absorption(EMA)has been carried out.Therefore,it is of great significance to elaborate the influence of TMDs on EMA in time to speed up the application.In this review,recent advances in the development of electromagnetic wave(EMW)absorbers based on TMDs,ranging from the VIB group to the VB group are summarized.Their compositions,microstructures,electronic properties,and synthesis methods are presented in detail.Particularly,the modulation of structure engineering from the aspects of heterostructures,defects,morphologies and phases are systematically summarized,focusing on optimizing impedance matching and increasing dielectric and magnetic losses in the EMA materials with tunable EMW absorption performance.Milestones as well as the challenges are also identified to guide the design of new TMDs based dielectric EMA materials with high performance.展开更多
Recent studies have successfully demonstrated high-Tc superconductivity in bilayer nickelate La3Ni2O7.However,research on modulating the structural and transport characteristics of La3Ni2O7 films by applying“chemical...Recent studies have successfully demonstrated high-Tc superconductivity in bilayer nickelate La3Ni2O7.However,research on modulating the structural and transport characteristics of La3Ni2O7 films by applying“chemical”compressive pressure through cation substitution is still limited.Here,we address this issue in the La_(3−x)Nd_(x)Ni_(2)O_(7)(x=0,1.0,1.5,2.0,and 2.5)thin film samples.It was found that using Nd3+with a smaller radius instead of La3+can reduce the c-axis lattice constant and shift the metal-insulator transition(MIT)temperature TMIT.To probe the origin of the MIT at cryogenic temperatures,experimental measurements of magnetoresistance were conducted,and theoretical analysis was carried out using the Kondo model,Hikami-Larkin-Nagaoka equation,and other methods.The results indicate that as Nd doping rises,the contributions of the Kondo effect and two-dimensional weak localization(WL)first decrease and then increase.The total contribution of WL and the Kondo effect in the mid-doped La_(1.5)Nd_(1.5)Ni_(2)O_(7)sample was the smallest,which to some extent explains the changes in TMIT.The Kondo effect dominates in other La_(3−x)Nd_(x)Ni_(2)O_(7)(x=0,1.0,2.0,and 2.5)samples.This work demonstrates that cation doping has a significant impact on bilayer nickelates,providing experimental evidence for understanding the physical mechanism of the MIT in bilayer nickelates.展开更多
The susceptibility of Pt catalyst surfaces to carbon monoxide(CO)poisoning in anodic hydrogen oxidation reaction(HOR)has been a critical constraint on the development of proton exchange membrane fuel cells(PEMFCs).Eff...The susceptibility of Pt catalyst surfaces to carbon monoxide(CO)poisoning in anodic hydrogen oxidation reaction(HOR)has been a critical constraint on the development of proton exchange membrane fuel cells(PEMFCs).Effectively regulating the electronic structure of Pt to enhance CO resistance is crucial for developing high-performance catalysts with robust anti-poisoning capabilities.Herein,the Pt/W@NCNF featured by Pt nanoparticles and atomical dispersed tungsten(W)sites on N-doped carbon nanofibers is developed for CO tolerance HOR catalyst.The presence of W enables the electron transfer from Pt,which promotes electron rearrangement in the Pt-5d orbitals.It not only optimizes the adsorption of H^(*) and CO^(*)on Pt,but also the OH^(*) intermediates adsorbed on the W sites oxidize the CO*adsorbed on Pt,thereby retaining more active sites for H_(2) adsorption and oxidation.The HOR exchange current density of Pt/W@NCNF reaches 1.35 times that of commercial Pt/C,and the limiting current density decreases by only 3.4%after introducing 1000 ppm CO in H_(2).Notably,the Pt/W@NCNF-based PEMFCs deliver markedly superior performance across a range of CO concentrations.The present study demonstrates that electronic modulation of Pt is an effective strategy for simultaneously achieving resistance to CO and promoted HOR activity.展开更多
Precise regulation of atomic and electronic structures of two-dimensional tungsten disulfide(WS_(2))is significant for rational design of high-performance and low-cost catalyst for acetylene hydrogenation to ethylene(...Precise regulation of atomic and electronic structures of two-dimensional tungsten disulfide(WS_(2))is significant for rational design of high-performance and low-cost catalyst for acetylene hydrogenation to ethylene(AHE),yet remains a major challenge.Herein,we report that by substituting a W atom of WS_(2) with a series of transition metal atoms,sulfur vacancy-confined Cu in the WS_(2) basal plane(Cu@WS_(2)-Sv)is theoretically screened as a superior non-noble metal-based catalyst with higher activity,selectivity,and stability for the AHE than other candidates.The co-adsorption of C_(2)H_(2) and H_(2) and hydrogenation of C_(2)H_(3)^(*) to C_(2)H_(4)^(*) are revealed as the key steps establishing a volcano-like activity trend among the candidates,which present Cu@WS_(2)-Sv as the optimum catalyst combined with molecular dynamics and reaction kinetics analyses.The kinetically more favorable desorption of C_(2)H_(4) than the over hydrogenation path validates a higher selectivity toward C_(2)H_(4) over C_(2)H_(6).Furthermore,a machine-learning model reveals the significant effect of d-electron number and electronegativity of the metal heteroatoms in modulating the AHE activity.展开更多
Construction of elaborate configuration to enhance the intrinsic activity of NiMo-based catalyst candidates holds promise for accelerating the hydrogen evolution reaction(HER)kinetics.Herein,a novel cerium-doped NiMo ...Construction of elaborate configuration to enhance the intrinsic activity of NiMo-based catalyst candidates holds promise for accelerating the hydrogen evolution reaction(HER)kinetics.Herein,a novel cerium-doped NiMo phosphate(labeled as Ce-NiMo(PO_(4))_(0.66))is designed and fabricated via a facile hydrothermal and phosphatization method.A comprehensive characterization reveals that the introduction of the rare metal element cerium with an enriched 4f electronic distribution near the Fermi level modulates the hybridization of the 3d-2p orbitals and optimizes the electronic structure of the NiMo-based phosphate catalysts,which leads to the synergy between the nickel-molybdenum dual sites and the phosphate active unit to synchronously enhance the water dissociation and proton dehydrogenation transfer of the HER process.Consequently,Ce-NiMo(PO_(4))0.66 exhibits excellent alkaline HER performance with overpotentials at 10 and 500 mA·cm^(-2)current densities being only 40 and 295 mV,respectively,and desirable long-term durability at industrial current densities of 500 mA·cm^(-2).An overall hydrazine splitting(OHzS)constructed with Ce-NiMo(PO_(4))_(0.66)as a hydrazine oxidation reaction(HzOR)and HER bifunctional electrocatalyst has been constructed to achieve industrial current densities at the low voltage of 0.92 V,verifying its practical feasibility for sustainable hydrogen production and degradation of hydrazine pollutants.This work highlights that regulating the 3d-2p hybridization state through the inducing 4f orbital electronic state is a feasible means for enhancing the HER activity of transition metal compound catalysts.展开更多
Polyvinyl chloride is the most widely used general-purpose plastic and plays a vital role in various industries.Mercury-based catalysts severely limit the green sustainability of industry.Non-metallic carbon materials...Polyvinyl chloride is the most widely used general-purpose plastic and plays a vital role in various industries.Mercury-based catalysts severely limit the green sustainability of industry.Non-metallic carbon materials are very promising alternatives in acetylene hydrochlorination,but their stability remains a challenge of major concern at present.Based on the principle of green chemistry,structurally tunable and defect-rich carbon materials were synthesized by hydrothermal carbonization and pyrolysis using glucose as carbon source and m-phenylenediamine as nitrogen source and cross-linking agent.Experimental characterization and density functional theory confirmed that pyridinic N was the main active site.The introduction of N not only regulated the formation of the hierarchically porous structure of the carbon material,but also increased the adsorption of HCl and decreased the adsorption strength of C_(2)H_(2).The synergistic effect of high N content and porous structure significantly enhanced the catalytic performance of the catalysts in acetylene hydrochlorination.The C_(2)H_(2)conversion was maintained at around98%after 100 h under the reaction conditions(T=220°C,GHSV(C_(2)H_(2))=30 h^(-1),V_(HCl)/VC_(2)H_(2)=1.15).Thus,the one-pot synthesis process used here is a good benchmark for future catalyst research.展开更多
Advancing aqueous zinc-ion batteries(AZIBs)are significantly challenged by the need to find cathode materials that can provide both high capacity and fast reaction kinetics.Tellurium telluride,a topological insulator,...Advancing aqueous zinc-ion batteries(AZIBs)are significantly challenged by the need to find cathode materials that can provide both high capacity and fast reaction kinetics.Tellurium telluride,a topological insulator,has emerged as a promising cathode candidate for AZIBs,garnering increasing attention.However,the complete understanding of its electrochemical reaction mechanism and its unsatisfactory energy storage performance are major obstacles to the practical use.In this work,we synthesize a bimetallic bismuth-nickel telluride with Te vacancies,defined as Bi_(2)Te_(3-x)/NiTe_(2),which forms a topological insulator/topological Dirac semimetal heterostructure through a hydrothermal approach.The electrochemical reaction mechanism of Bi_(2)Te_(3-x)/NiTe_(2),along with its phase and structural changes are elucidated by using in-situ X-ray diffraction,various electrochemical techniques,and ex-situ characterizations.The influences of Bi_(2)Te_(3-x)/NiTe_(2)on the electronic structure,interracial electron transfer,migration barrier,and ion adsorption energy are investigated by using density functional theory calculations.Our findings reveal that Bi_(2)Te_(3-x)/NiTe_(2)exhibits excellent specific capacity,stable cycling,and superior rate capability as a cathode material for AZIBs.Moreover,further studies demonstrate that Bi_(2)Te_(3-x)/NiTe_(2)maintains exceptional performance at low temperatures of-15 and-5℃,and also retains stability and flexibility when integrated into flexible battery packs.展开更多
C1 chemistry is the essence of coal chemistry and natural gas chemistry. Catalytic methods to efficiently convert C1 molecules into fuels and chemicals have been extensively studied. Syngas（CO ＋H_2） conversion is t...C1 chemistry is the essence of coal chemistry and natural gas chemistry. Catalytic methods to efficiently convert C1 molecules into fuels and chemicals have been extensively studied. Syngas（CO ＋H_2） conversion is the most important industrial reaction system in C1 chemistry, and Fe and Co catalysts, two major industrial catalysts, have been the focus of fundamental research and industrial application. In the last decade, considerable research efforts have been devoted to discoveries concerning catalyst structure and increasing market demands for olefins and oxygenates. Since the development of efficient catalysts would strongly benefit from catalyst design and the establishment of a new reaction system, this review comprehensively overviews syngas conversion in three main reactions, highlights the advances recently made and the challenges that remain open, and will stimulate future research activities. The first part of the review summarizes the breakthroughs in Fischer-Tropsch synthesis regarding the optimization of activity and stability, determination of the active phase, and mechanistic studies. The second part overviews the modulation of catalytic structure and product selectivity for Fischer-Tropsch to olefins（FTO）. Catalysts designed to produce higher alcohols, as well as to tune product selectivity in C1 chemistry, are described in the third section. Finally, present challenges in syngas conversion are proposed, and the solutions and prospects are discussed from the viewpoint of fundamental research and practical application. This review summarizes the latest advances in the design, preparation, and application of Fe/Co-based catalysts toward syngas conversion and presents the challenges and future directions in producing value-added fuels.展开更多
Oxygen evolution reaction(OER)as the foremost stumbling block to generate cost-effective clean fuels has received extensive attention in recent years.But,it still maintains the challenge to manipulate the geometric an...Oxygen evolution reaction(OER)as the foremost stumbling block to generate cost-effective clean fuels has received extensive attention in recent years.But,it still maintains the challenge to manipulate the geometric and electronic structure during single reaction process under the same conditions.Herein,we report a simple self-template strategy to generate honeycomb-like Ni_(2)P/N,P-C hybrids with preferred electronic architecture.Experiments coupled with theoretical results revealed that the synthesized catalyst has two characteristics:firstly,the unique honeycomb-like morphology not only enables the fully utilization of catalytic active sites but also optimizes the mass/electron transportation pathway,which favor the diffusion of electrolyte to accessible active sites.Secondly,N,P-C substrate,on the one hand,largely contributes the electronic distribution near Fermi level(E_(F))thus boosting its electrical conductivity.On the other hand,the support effect result in the upshift of d-band center and electropositivity of Ni sites,which attenuates the energy barrier for the adsorption of OH~àand the formation of*OOH.In consequence,the optimized Ni_(2)P/N,P-C catalysts feature high electrocatalytic activity towards OER(a low overpotential of 252 m V to achieve10 m A cm^(-2))and 10 h long-term stability,the outstanding performance is comparable to most of transition metal catalysts.This work gives a innovative tactics for contriving original OER electrocatalysts,inspirng deeper understanding of fabricating catalysts by combining theoretical simulation and experiment design.展开更多
Two-dimensional(2D)metal organic frameworks(MOFs)are emerging as low-cost oxygen evolution reaction(OER)electrocatalysts,however,suffering aggregation and poor operation stability.Herein,ultrafine Fe_(3)O_(4) nanopart...Two-dimensional(2D)metal organic frameworks(MOFs)are emerging as low-cost oxygen evolution reaction(OER)electrocatalysts,however,suffering aggregation and poor operation stability.Herein,ultrafine Fe_(3)O_(4) nanoparticles(diameter:6±2 nm)are homogeneously immobilized on 2D Ni based MOFs(Ni-BDC,thickness:5±1 nm)to improve the OER stability.Electronic structure modulation for enhanced catalytic activity is studied via adjusting the amount of Fe_(3)O_(4) nanoparticles on Ni-BDC.The optimal Fe_(3)O_(4)/Ni-BDC achieves the best OER performance with an overpotential of 295 mV at 10 mA cm^(-2),a Tafel slope of 47.8 mV dec^(-1) and a considerable catalytic durability of more than 40 h(less than 5 h for Ni-BDC alone).DFT calculations confirm that the active sites for Fe_(3)O_(4)/Ni-BDC are mainly contributed by Fe species with a higher oxidation state,and the potential-determining step(PDS)is the formation of the adsorbed O*species,which are facilitated in the composite.展开更多
With the continuous improvement of China's science and technology, the design method of steel structure is also more and more, how to better apply the module building design method to the related buildings, is the...With the continuous improvement of China's science and technology, the design method of steel structure is also more and more, how to better apply the module building design method to the related buildings, is the current issue to focus on consideration. Therefore, this paper will focus on the design method of multi-layer steel structure module and steel frame composite building structure, and analyze and study its structure, so as to improve the utilization rate of steel structure and promote the development of the construction industry.展开更多
The importance of the zeros of multwariable linear systems is well-knoiun in terms of measure obstructions to the controllability and the. observability. In this paper, a recursive decarnposi Am oj interconnected syst...The importance of the zeros of multwariable linear systems is well-knoiun in terms of measure obstructions to the controllability and the. observability. In this paper, a recursive decarnposi Am oj interconnected systems is outlined by taking into account the sequential structure of the connnections. The paper extends the, coordinate, module-theoretic studies from the elementary algebraic systems theory to include the case oj such linear interconnected systems which need not to be controllable or observable. Also, the properties of controllability and observability, the decoupling zeros and the signal Making issues are characterized.展开更多
基金support from the National Key Research and Development Program of China(Grant No.2021YFB3501402)the National Natural Science Foundation of China(Grant Nos.52250313 and 52121001)Yang Liu and Chen Si acknowledge financial support from the National Natural Science Foundation of China(Grant No.12274013).
文摘Significant two-way shape memory effect(TWSME)was achieved in single crystals of single-phase multielement Ni42-x Cu8 Cox Mn37 Ga13(8≤x≤12)alloys by performing thermomechanical training.However,anomalous dependence of the martensitic transformation temperature span on Co content was observed.Before training,quite a narrow temperature span of the martensitic transformation,nearly independent of the Co content,was observed in all single crystals.After training the temperature span was still narrow for 8≤x≤10.9 but was obviously expanded for 10.9<x≤12.High-resolution transmission electron microscopy revealed that at the atomic scale,there exists incommensurate modulated structure in the single phase single crystals,as evidenced by nonperiodic satellite spots in the selected area electronic diffraction patterns.Moreover,the modulated wave vector of the satellite spots was increased by higher Co contents.Combining first principal calculations it was considered that the incommensurate modulated structure originates from the formation of Co-Co pairs.After training arrays of ordered dislocations with the same Burgers vector were introduced for 8≤x≤10.9 but the network of dislocations was formed for 10.9<x≤12.Based on analysis of transmission electron microscopy,geometric phase,thermodynamics,and Landau theory,it was considered that the austenite/martensite phase interface was pinned by the network of dislocations,expanding the temperature span of the martensitic transformation.This work supplies new insights for understanding the microstructure and martensitic transformation of Ni-Mn-Ga-based alloys.
文摘The Nd Fe B/Co multilayer films were prepared by magnetron sputtering. After that, the samples were annealed at 600 ℃ for 20 min. The surface morphology, phase structures and magnetic properties of Mo（50 nm）/[Nd Fe B（100 nm）/Co（y）]×10/Mo（50 nm） thin films were researched by AFM, XRD and VSM, respectively. The results show that the films show stronger perpendicular magnetic anisotropy. When the thickness of Co layers is 10 nm, the coercivity Hc⊥ is the maximum, 295 k A/m. However, for y=10-20, the reduced remanence M/Ms of films has increased. When the thickness of Co layers is 20-30 nm, the Nd Fe B/Co multilayer films obtained more superior magnetic properties with M/Ms =0.95.
文摘1.IntroductionSince the theory of spinodal decompo-sition in a supersaturated solid solution wasformulated by Hillert[1]and Cahn[2],thephenomena of spinodal decomposition havebeen found in many alloys.Tamura[3]haspointed out that spinodal decompositioncould also occur in maraging steels.A mod-ulated structure in 8Ni maraging steel was
基金Supported by the National Natural Science Foundation of China(No.90922034)
文摘A series of perovskite compounds of La1-x-yCaxKyMnO3 was prepared by hydrothermal disproportionation reaction of MnO2. The three oxidation states of manganese（Mn3＋, Mn4＋ and Mn5＋） can stably exist in the compounds. Under room temperature conditions, twice and three times modulated structure produced by the charge ordering can be observed by X-ray diffraction（XRD）, select area electron diffraction（SAED） and high resolution transmission electron microscopy（HR-TEM）. The splits of the diffraction peaks of the single crystals confirmed by synchrotron X-ray diffraction experiment are in accordance with those of the powder sample. The existence of the different oxidation states of Mn3＋, Mn4＋ and Mn5＋ can be considered to be the dominating reason of the complicated room temperature modulated structure.
基金financial support from the National Natural Science Foundation of China(21878192 and 51904193)the Fundamental Research Funds for the Central Universities(YJ2021141)the Science and Technology Cooperation Special Fund of Sichuan University and Zigong City(2021CDZG-14)
文摘Efficient energy storage devices with suitable electrode materials,that integrate high power and high energy,are the crucial requisites of the renewable power source,which have unwrapped new possibilities in the sustainable development of energy and the environment.Herein,a facile collagen microstructure modulation strategy is proposed to construct a nitrogen/oxygen dual-doped hierarchically porous carbon fiber with ultrahigh specific surface area(2788 m^(2)g^(-1))and large pore volume(4.56 cm^(3)g^(-1))via local microfibrous breakage/disassembly of natural structured proteins.Combining operando spectroscopy and density functional theory unveil that the dual-heteroatom doping could effectively regulate the electronic structure of carbon atom framework with enhanced electric conductivity and electronegativity as well as decreased diffusion resistance in favor of rapid pseudocapacitive-dominated Li^(+)-storage(353 mAh g^(-1)at 10 A g^(-1)).Theoretical calculations reveal that the tailored micro-/mesoporous structures favor the rapid charge transfer and ion storage,synergistically realizing high capacity and superior rate performance for NPCF-H cathode(75.0 mAh g^(-1)at 30 A g^(-1)).The assembled device with NPCF-H as both anode and cathode achieves extremely high energy density(200 Wh kg^(-1))with maximum power density(42600 W kg^(-1))and ultralong lifespan(80%capacity retention over 10000 cycles).
文摘Single-atom catalysts are promising for H_(2)O_(2) photosynthesis from O_(2) and H_(2)O,but their efficiency is still limited by the ill-defined electronic structure.In this study,Co single-atoms with unique four planar N-coordination and one axial P-coordination(Co-N_(4)P_(1))are decorated on the lateral edges of nanorod-like crystalline g-C_(3)N_(4)(CCN)photocatalysts.Significantly,the electronic structures of central Co as active sites for O_(2) reduction reaction(ORR)and planar N-coordinator as active sites for H_(2)O oxidation reaction(WOR)in Co-N_(4)P_(1) can be well regulated by the synergetic effects of introducing axial P-coordinator,in contrast to the decorated Co single-atoms with only four planar N-coordination(Co-N_(4)).Specifically,directional photoelectron accumulation at central Co active sites,induced by an introduced midgap level in Co-N_(4)P_(1),mediates the ORR active sites from 4e–-ORR-selective terminal–NH_(2) sites to 2e–-ORR-selective Co sites,moreover,an elevated d-band center of Co 3d orbital strengthens ORR intermediate*OOH adsorption,thus jointly facilitating a highly selective and active 2e^(–)-ORR pathway to H_(2)O_(2) photosynthesis.Simultaneously,a downshifted p-band center of N_(2)p orbital in Co-N_(4)P_(1) weakens WOR intermediate*OH adsorption,thus enabling a preferable 2e^(–)-WOR pathway toward H_(2)O_(2) photosynthesis.Subsequently,Co-N_(4)P_(1) exhibits exceptional H_(2)O_(2) photosynthesis efficiency,reaching 295.6μmol g^(-1) h^(-1) with a remarkable solar-to-chemical conversion efficiency of 0.32%,which is 15 times that of Co-N_(4)(19.2μmol g^(-1) h^(-1))and 10 times higher than CCN(27.6μmol g^(-1) h^(-1)).This electronic structure modulation on single-atom catalysts offers a promising strategy for boosting the activity and selectivity of H_(2)O_(2) photosynthesis.
基金financially supported by the National Natural Science Foundation of China(51872090,51772097)Hebei Natural Science Fund for Distinguished Young Scholar(E2019209433)+3 种基金Youth Talent Program of Hebei Provincial Education Department(BJ2018020)Natural Science Foundation of Hebei Province(E2020209151,E2024209029)National Key R&D Plan Project(2022YFB4200305)Research Projects of China National Petroleum Corporation(2024ZG50,2023DQ03-04)。
文摘The sluggish electrochemical catalytic activity of the graphite felt electrodes for anode reaction is still a barrier for achieving high-performance vanadium redox flow battery(VRFB).It is significant to leverage the exceptional conductivity,excellent electrocatalytic activity,and structural tunability of MXene to address this issue.Herein,this work introduces nitrogen atoms to modulate the carbon layer structure of Ti_(3)C_(2)T_(x)MXene,inducing a reconfiguration of the local electronic structure,which enhances the anode interface activity and thereby improves the performance of VRFB.Ti_(3)C_(2)T_(x)exhibits high conductivity,excellent hydrophilicity,and a large specific surface area,providing excellent interface characteristics for V^(3+)/V^(2+)redox reaction.Moreover,interlayer treatment to modulate the mesoporous structure of MXene further increases the reactive surface area.Importantly,doping nitrogen atoms at carbon layer induces lattice distortions in Ti_(3)C_(2)T_(x),which enhances the charge transfer processes of the V^(3+)/V^(2+)redox reaction.The catalysis mechanism is also validated through density functional theory.Furthermore,the modified graphite felt electrode,as the anode of VRFB,relieves a higher energy efficiency of 68%at 250 mA cm^(-2),while the pristine electrode cannot operate at this current density.In addition,at 150 mA cm^(-2),the modified battery maintains energy efficiency at 75%without degradation after 500 cycles.This study utilizes rational atomic-level engineering for effective structural modulation to significantly enhance the catalytic activity of electrode reaction,offering a unique perspective for developing high-performance MXene electrocatalysts of VRFB.
文摘Metal Fe/Pd compositionally modulated films(CMFs) were prepared by vapour depo- sition from two sources onto glass substrate under vacuum.The modulation and crystal structures of the films were examined by X-ray diffraction.The magnetic properties were determined by vibrating sample magnetometer.The Pd layers in the Fe/Pd CMFs are of fcc structure,and the Fe layer structure transits from bcc into amorphous,state with decreasing thickness of Fe layer.The dependence of specific saturation magnetization on thickness of Fe layers has also been discussed.
基金This work was supported by the National Natural Science Foundation of China(52372289,52102368,52072192 and 51977009)Regional Joint Fund for Basic Research and Applied Basic Research of Guangdong Province(No.2020SA001515110905).
文摘The laminated transition metal disulfides(TMDs),which are well known as typical two-dimensional(2D)semiconductive materials,possess a unique layered structure,leading to their wide-spread applications in various fields,such as catalysis,energy storage,sensing,etc.In recent years,a lot of research work on TMDs based functional materials in the fields of electromagnetic wave absorption(EMA)has been carried out.Therefore,it is of great significance to elaborate the influence of TMDs on EMA in time to speed up the application.In this review,recent advances in the development of electromagnetic wave(EMW)absorbers based on TMDs,ranging from the VIB group to the VB group are summarized.Their compositions,microstructures,electronic properties,and synthesis methods are presented in detail.Particularly,the modulation of structure engineering from the aspects of heterostructures,defects,morphologies and phases are systematically summarized,focusing on optimizing impedance matching and increasing dielectric and magnetic losses in the EMA materials with tunable EMW absorption performance.Milestones as well as the challenges are also identified to guide the design of new TMDs based dielectric EMA materials with high performance.
基金supported by the Natural Science Foundation of Guangdong Province of China(Grant No.2025A1515011071)the National Natural Science Foundation of China(Grant Nos.92065110,11974048,and 12074334)the Beijing Municipal Natural Science Foundation Key Research Topics(Grant No.Z230006)。
文摘Recent studies have successfully demonstrated high-Tc superconductivity in bilayer nickelate La3Ni2O7.However,research on modulating the structural and transport characteristics of La3Ni2O7 films by applying“chemical”compressive pressure through cation substitution is still limited.Here,we address this issue in the La_(3−x)Nd_(x)Ni_(2)O_(7)(x=0,1.0,1.5,2.0,and 2.5)thin film samples.It was found that using Nd3+with a smaller radius instead of La3+can reduce the c-axis lattice constant and shift the metal-insulator transition(MIT)temperature TMIT.To probe the origin of the MIT at cryogenic temperatures,experimental measurements of magnetoresistance were conducted,and theoretical analysis was carried out using the Kondo model,Hikami-Larkin-Nagaoka equation,and other methods.The results indicate that as Nd doping rises,the contributions of the Kondo effect and two-dimensional weak localization(WL)first decrease and then increase.The total contribution of WL and the Kondo effect in the mid-doped La_(1.5)Nd_(1.5)Ni_(2)O_(7)sample was the smallest,which to some extent explains the changes in TMIT.The Kondo effect dominates in other La_(3−x)Nd_(x)Ni_(2)O_(7)(x=0,1.0,2.0,and 2.5)samples.This work demonstrates that cation doping has a significant impact on bilayer nickelates,providing experimental evidence for understanding the physical mechanism of the MIT in bilayer nickelates.
基金supported by the National Natural Science Foundation of China(22179034,22279030)the Natural Science Foundation of Heilongjiang Province(ZD2023B002).
文摘The susceptibility of Pt catalyst surfaces to carbon monoxide(CO)poisoning in anodic hydrogen oxidation reaction(HOR)has been a critical constraint on the development of proton exchange membrane fuel cells(PEMFCs).Effectively regulating the electronic structure of Pt to enhance CO resistance is crucial for developing high-performance catalysts with robust anti-poisoning capabilities.Herein,the Pt/W@NCNF featured by Pt nanoparticles and atomical dispersed tungsten(W)sites on N-doped carbon nanofibers is developed for CO tolerance HOR catalyst.The presence of W enables the electron transfer from Pt,which promotes electron rearrangement in the Pt-5d orbitals.It not only optimizes the adsorption of H^(*) and CO^(*)on Pt,but also the OH^(*) intermediates adsorbed on the W sites oxidize the CO*adsorbed on Pt,thereby retaining more active sites for H_(2) adsorption and oxidation.The HOR exchange current density of Pt/W@NCNF reaches 1.35 times that of commercial Pt/C,and the limiting current density decreases by only 3.4%after introducing 1000 ppm CO in H_(2).Notably,the Pt/W@NCNF-based PEMFCs deliver markedly superior performance across a range of CO concentrations.The present study demonstrates that electronic modulation of Pt is an effective strategy for simultaneously achieving resistance to CO and promoted HOR activity.
文摘Precise regulation of atomic and electronic structures of two-dimensional tungsten disulfide(WS_(2))is significant for rational design of high-performance and low-cost catalyst for acetylene hydrogenation to ethylene(AHE),yet remains a major challenge.Herein,we report that by substituting a W atom of WS_(2) with a series of transition metal atoms,sulfur vacancy-confined Cu in the WS_(2) basal plane(Cu@WS_(2)-Sv)is theoretically screened as a superior non-noble metal-based catalyst with higher activity,selectivity,and stability for the AHE than other candidates.The co-adsorption of C_(2)H_(2) and H_(2) and hydrogenation of C_(2)H_(3)^(*) to C_(2)H_(4)^(*) are revealed as the key steps establishing a volcano-like activity trend among the candidates,which present Cu@WS_(2)-Sv as the optimum catalyst combined with molecular dynamics and reaction kinetics analyses.The kinetically more favorable desorption of C_(2)H_(4) than the over hydrogenation path validates a higher selectivity toward C_(2)H_(4) over C_(2)H_(6).Furthermore,a machine-learning model reveals the significant effect of d-electron number and electronegativity of the metal heteroatoms in modulating the AHE activity.
基金supported by the National Natural Science Foundation of China(No.22278097)Heilongjiang Province Universities Basic Scientific Research Business Fee Project(Nos.2022-KYYWF-0568 and 2023-KYYWF-0527)+2 种基金the Natural Science Foundation of Heilongjiang Province(No.YQ2021B004)the Postdoctoral fellowship of Heilongjiang Province(No.LBH-Z23156)the Postdoctoral Fellowship Program of CPSF(No.GZC20233449).
文摘Construction of elaborate configuration to enhance the intrinsic activity of NiMo-based catalyst candidates holds promise for accelerating the hydrogen evolution reaction(HER)kinetics.Herein,a novel cerium-doped NiMo phosphate(labeled as Ce-NiMo(PO_(4))_(0.66))is designed and fabricated via a facile hydrothermal and phosphatization method.A comprehensive characterization reveals that the introduction of the rare metal element cerium with an enriched 4f electronic distribution near the Fermi level modulates the hybridization of the 3d-2p orbitals and optimizes the electronic structure of the NiMo-based phosphate catalysts,which leads to the synergy between the nickel-molybdenum dual sites and the phosphate active unit to synchronously enhance the water dissociation and proton dehydrogenation transfer of the HER process.Consequently,Ce-NiMo(PO_(4))0.66 exhibits excellent alkaline HER performance with overpotentials at 10 and 500 mA·cm^(-2)current densities being only 40 and 295 mV,respectively,and desirable long-term durability at industrial current densities of 500 mA·cm^(-2).An overall hydrazine splitting(OHzS)constructed with Ce-NiMo(PO_(4))_(0.66)as a hydrazine oxidation reaction(HzOR)and HER bifunctional electrocatalyst has been constructed to achieve industrial current densities at the low voltage of 0.92 V,verifying its practical feasibility for sustainable hydrogen production and degradation of hydrazine pollutants.This work highlights that regulating the 3d-2p hybridization state through the inducing 4f orbital electronic state is a feasible means for enhancing the HER activity of transition metal compound catalysts.
基金supported by the Tianchi Innovation Leading Talent Development Fund(No.CZ002710)in Xinjiangthe Taishan Scholars Program of Shandong Province(No.tsqn202103051)+4 种基金the Project of Science and Technology Development of Yantai City(No.2023JCYJ073)Natural science foundation of Shandong province(No.ZR2023MB064)special funds for over provincial level leading talent of Yantai citythe Start-Up Foundation for High-level Professionals of Shihezi University(No.RCZK201932)Tianshan Talents Training Program of Xinjiang(Science and Technology Innovation Team,No.2022TSYCTD0021)。
文摘Polyvinyl chloride is the most widely used general-purpose plastic and plays a vital role in various industries.Mercury-based catalysts severely limit the green sustainability of industry.Non-metallic carbon materials are very promising alternatives in acetylene hydrochlorination,but their stability remains a challenge of major concern at present.Based on the principle of green chemistry,structurally tunable and defect-rich carbon materials were synthesized by hydrothermal carbonization and pyrolysis using glucose as carbon source and m-phenylenediamine as nitrogen source and cross-linking agent.Experimental characterization and density functional theory confirmed that pyridinic N was the main active site.The introduction of N not only regulated the formation of the hierarchically porous structure of the carbon material,but also increased the adsorption of HCl and decreased the adsorption strength of C_(2)H_(2).The synergistic effect of high N content and porous structure significantly enhanced the catalytic performance of the catalysts in acetylene hydrochlorination.The C_(2)H_(2)conversion was maintained at around98%after 100 h under the reaction conditions(T=220°C,GHSV(C_(2)H_(2))=30 h^(-1),V_(HCl)/VC_(2)H_(2)=1.15).Thus,the one-pot synthesis process used here is a good benchmark for future catalyst research.
基金supported by the National Natural Science Foundation of China(No.52372223)the Science Foundation of Shaanxi Province(No.2023-JC-ZD-03 and 2022GD-TSLD-15)Shaanxi Fundamental Science Research Project for Mathematics and Physics(No.23JSQ005)。
文摘Advancing aqueous zinc-ion batteries(AZIBs)are significantly challenged by the need to find cathode materials that can provide both high capacity and fast reaction kinetics.Tellurium telluride,a topological insulator,has emerged as a promising cathode candidate for AZIBs,garnering increasing attention.However,the complete understanding of its electrochemical reaction mechanism and its unsatisfactory energy storage performance are major obstacles to the practical use.In this work,we synthesize a bimetallic bismuth-nickel telluride with Te vacancies,defined as Bi_(2)Te_(3-x)/NiTe_(2),which forms a topological insulator/topological Dirac semimetal heterostructure through a hydrothermal approach.The electrochemical reaction mechanism of Bi_(2)Te_(3-x)/NiTe_(2),along with its phase and structural changes are elucidated by using in-situ X-ray diffraction,various electrochemical techniques,and ex-situ characterizations.The influences of Bi_(2)Te_(3-x)/NiTe_(2)on the electronic structure,interracial electron transfer,migration barrier,and ion adsorption energy are investigated by using density functional theory calculations.Our findings reveal that Bi_(2)Te_(3-x)/NiTe_(2)exhibits excellent specific capacity,stable cycling,and superior rate capability as a cathode material for AZIBs.Moreover,further studies demonstrate that Bi_(2)Te_(3-x)/NiTe_(2)maintains exceptional performance at low temperatures of-15 and-5℃,and also retains stability and flexibility when integrated into flexible battery packs.
文摘C1 chemistry is the essence of coal chemistry and natural gas chemistry. Catalytic methods to efficiently convert C1 molecules into fuels and chemicals have been extensively studied. Syngas（CO ＋H_2） conversion is the most important industrial reaction system in C1 chemistry, and Fe and Co catalysts, two major industrial catalysts, have been the focus of fundamental research and industrial application. In the last decade, considerable research efforts have been devoted to discoveries concerning catalyst structure and increasing market demands for olefins and oxygenates. Since the development of efficient catalysts would strongly benefit from catalyst design and the establishment of a new reaction system, this review comprehensively overviews syngas conversion in three main reactions, highlights the advances recently made and the challenges that remain open, and will stimulate future research activities. The first part of the review summarizes the breakthroughs in Fischer-Tropsch synthesis regarding the optimization of activity and stability, determination of the active phase, and mechanistic studies. The second part overviews the modulation of catalytic structure and product selectivity for Fischer-Tropsch to olefins（FTO）. Catalysts designed to produce higher alcohols, as well as to tune product selectivity in C1 chemistry, are described in the third section. Finally, present challenges in syngas conversion are proposed, and the solutions and prospects are discussed from the viewpoint of fundamental research and practical application. This review summarizes the latest advances in the design, preparation, and application of Fe/Co-based catalysts toward syngas conversion and presents the challenges and future directions in producing value-added fuels.
基金supported by the Major Science and Technology Program for Water Pollution Control and Treatment(2017ZX07402001)the Ministry of Science and Technology of China for their financial support and the associated project is the Key Program for International S&T Cooperation Projects(No.2018YFE0124600)。
文摘Oxygen evolution reaction(OER)as the foremost stumbling block to generate cost-effective clean fuels has received extensive attention in recent years.But,it still maintains the challenge to manipulate the geometric and electronic structure during single reaction process under the same conditions.Herein,we report a simple self-template strategy to generate honeycomb-like Ni_(2)P/N,P-C hybrids with preferred electronic architecture.Experiments coupled with theoretical results revealed that the synthesized catalyst has two characteristics:firstly,the unique honeycomb-like morphology not only enables the fully utilization of catalytic active sites but also optimizes the mass/electron transportation pathway,which favor the diffusion of electrolyte to accessible active sites.Secondly,N,P-C substrate,on the one hand,largely contributes the electronic distribution near Fermi level(E_(F))thus boosting its electrical conductivity.On the other hand,the support effect result in the upshift of d-band center and electropositivity of Ni sites,which attenuates the energy barrier for the adsorption of OH~àand the formation of*OOH.In consequence,the optimized Ni_(2)P/N,P-C catalysts feature high electrocatalytic activity towards OER(a low overpotential of 252 m V to achieve10 m A cm^(-2))and 10 h long-term stability,the outstanding performance is comparable to most of transition metal catalysts.This work gives a innovative tactics for contriving original OER electrocatalysts,inspirng deeper understanding of fabricating catalysts by combining theoretical simulation and experiment design.
基金support from the Chinese Scholarship Council(201706220080)for W.H.the Natural Science Foundation of Hunan Province(2019JJ50526)for C.P.+1 种基金The Danish Council for Independent Research for the YDUN project(DFF 4093-00297)to J.Z.Villum Experiment(grant No.35844)for X.X.
文摘Two-dimensional(2D)metal organic frameworks(MOFs)are emerging as low-cost oxygen evolution reaction(OER)electrocatalysts,however,suffering aggregation and poor operation stability.Herein,ultrafine Fe_(3)O_(4) nanoparticles(diameter:6±2 nm)are homogeneously immobilized on 2D Ni based MOFs(Ni-BDC,thickness:5±1 nm)to improve the OER stability.Electronic structure modulation for enhanced catalytic activity is studied via adjusting the amount of Fe_(3)O_(4) nanoparticles on Ni-BDC.The optimal Fe_(3)O_(4)/Ni-BDC achieves the best OER performance with an overpotential of 295 mV at 10 mA cm^(-2),a Tafel slope of 47.8 mV dec^(-1) and a considerable catalytic durability of more than 40 h(less than 5 h for Ni-BDC alone).DFT calculations confirm that the active sites for Fe_(3)O_(4)/Ni-BDC are mainly contributed by Fe species with a higher oxidation state,and the potential-determining step(PDS)is the formation of the adsorbed O*species,which are facilitated in the composite.
文摘With the continuous improvement of China's science and technology, the design method of steel structure is also more and more, how to better apply the module building design method to the related buildings, is the current issue to focus on consideration. Therefore, this paper will focus on the design method of multi-layer steel structure module and steel frame composite building structure, and analyze and study its structure, so as to improve the utilization rate of steel structure and promote the development of the construction industry.
文摘The importance of the zeros of multwariable linear systems is well-knoiun in terms of measure obstructions to the controllability and the. observability. In this paper, a recursive decarnposi Am oj interconnected systems is outlined by taking into account the sequential structure of the connnections. The paper extends the, coordinate, module-theoretic studies from the elementary algebraic systems theory to include the case oj such linear interconnected systems which need not to be controllable or observable. Also, the properties of controllability and observability, the decoupling zeros and the signal Making issues are characterized.
