Developing a chiral material as versatile and universal chiral stationary phase(CSP) for chiral separation in diverse chromatographic techniques simultaneously is of great significance.In this study,we demonstrated fo...Developing a chiral material as versatile and universal chiral stationary phase(CSP) for chiral separation in diverse chromatographic techniques simultaneously is of great significance.In this study,we demonstrated for the first time that a chiral metal-organic cage(MOC),[Zn_(6)M_(4)],as a universal chiral recognition material for both multi-mode high-performance liquid chromatography(HPLC) and capillary gas chromatography(GC) enantioseparation.Two novel HPLC CSPs with different bonding arms(CSP-A with a cationic imidazolium bonding arm and CSP-B with an alkyl chain bonding arm) were prepared by clicking of functionalized chiral MOC [Zn_(6)M_(4)] onto thiolated silica via thiol-ene click chemistry.Meanwhile,a capillary GC column statically coated with the chiral MOC [Zn_(6)M_(4)] was also fabricated.The results showed that the chiral MOC exhibits excellent enantioselectivity not only in normal phase HPLC(NP-HPLC) and reversed phase(RP-HPLC) but also in GC,and various racemates were well separated,including alcohols,diols,esters,ketones,ethers,amines,and epoxides.Importantly,CSP-A and CSP-B are complementary to commercially available Chiralcel OD-H and Chiralpak AD-H columns in enantioseparation,which can separate some racemates that could not be or could not well be separated by the two widely used commercial columns,suggesting the great potential of the two prepared CSPs in enantioseparation.This work reveals that the chiral MOC is potential versatile chiral recognition materials for both HPLC and GC,and also paves the way to expand the potential applications of MOCs.展开更多
Exploring the synthesis of novel structures is crucial for the development of functional materials.In this context,a novel and intriguing 3d-5p heterometallic cluster-substituted polyoxotungstate material,H_(29)Na_(9)...Exploring the synthesis of novel structures is crucial for the development of functional materials.In this context,a novel and intriguing 3d-5p heterometallic cluster-substituted polyoxotungstate material,H_(29)Na_(9)(H_(2)O)_(21){Ca(H_(2)O)_(2)@Sb_(12)O_(18)[Ni_(2)(OH)(A-α-Si W_(10)O_(37))]_(3)}_(2)·40H_(2)O(1),was constructed using Keggintype polyoxotungstate A-α-Si W_(10)O_(37),along with Ni and Sb elements.The structure features a Tdsymmetric Sb_(12)O_(18)({Sb_(12)})cage that encapsulates an 8-coordinate Ca^(2+)ion at its face.Additionally,the{Sb_(12)}cage forms an 18-nuclear 3d-5p heterometallic cluster by connecting with three di-nuclear nickel clusters through shared oxygen atoms.Electrochemical impedance spectra studies reveal that the single crystal of 1 achieves a proton conductivity of 1.11×10^(-1)S/cm along the[110]direction and 1.04×10^(-1)S/cm along the[100]direction at 85℃ and 98%relative humidity(RH).Furthermore,the powder form of 1 exhibits a proton conductivity of 3.00×10^(-2)S/cm.These findings suggest that compound 1 holds promise as a practical proton conducting material.展开更多
Rational design and synthesis of low-cost trifunctional electrocatalysts with improved stability and superior electrocatalytic activity for oxygen reduction reaction(ORR),oxygen evolution reaction(OER),and hydrogen ev...Rational design and synthesis of low-cost trifunctional electrocatalysts with improved stability and superior electrocatalytic activity for oxygen reduction reaction(ORR),oxygen evolution reaction(OER),and hydrogen evolution reaction(HER) are highly desirable but remain as the bottlenecks at the current state of technology.In this paper,the cobalt-iron(Co-Fe) composite supported on nitrogen-doped carbon nanotubes(CoFe composite/NCNTs) is synthesized.The intrinsic OER and HER catalytic activities of this CoFe composite/NCNTs composite are significantly improved with palladium(Pd) nanocluster decoration [Pd-coated(CoFe composite/NCNTs)].The as-prepared Pd-coated(CoFe composite/NCNTs) catalyst exhibits excellent trifunctional electrocatalytic activity and stability due to the interfacial coupling between Pd and(CoFe composite/NCNTs).This catalyst is successfully employed in the water electrolysis cell as both OER and HER electrode catalysts,flexible rechargeable Zn-air battery as the bifunctional ORR and OER electrode catalyst.The cell voltage of this catalyst-coated electrodes requires only 1.60 V to achieve 10 mA cm^(-2) current density for water electrolysis cell,which is comparable to and even better than that of Pt/C and Ir/C based cell.The primary Zn-air battery using this catalyst shows a constant high open-circuit voltage(OCV) of 1.47 V and a maximum power density of 261 mW cm^(-2) in the flooded mode configuration.Most importantly,a flexible Zn-air battery with this catalyst runs very smoothly without a change in voltage gap during flat,bending,and twisting positions.展开更多
Metal-doped carbon materials, as one of the most important electrocatalytic catalysts for CO_(2)reduction reaction(CO_(2)RR), have attracted increasing attention. Herein, a series of Cu cluster embedded highly porous ...Metal-doped carbon materials, as one of the most important electrocatalytic catalysts for CO_(2)reduction reaction(CO_(2)RR), have attracted increasing attention. Herein, a series of Cu cluster embedded highly porous nanofibers have been prepared through the carbonization of electro-spun MOF/PAN nanofibers.The obtained Cu cluster doped porous nanofibers possessed fibrous morphology, high porosity, conductivity, and uniformly dispersed Cu clusters, which could be applied as promising CO_(2)RR catalysts. Specifically, best of them, MCP-500 exhibited high catalytic performance for CO_(2)RR, in which the Faradaic efficiency of CO(FECO) was as high as 98% at-0.8 V and maintained above 95% after 10 h continuous electrocatalysis. The high performance might be attributed to the synergistic effect of tremendously layered graphene skeleton and uniformly dispersed Cu clusters that could largely promote the electron conductivity, mass transfer and catalytic activity during the electrocatalytic CO_(2)RR process. This attempt will provide a new idea to design highly active CO_(2)RR electrocatalyst.展开更多
Two-dimensional metal dichalcogenides have been evidenced as potential electrocatalysts for hydrogen evolution reaction(HER);however,their application is limited by a poor oxygen evolution reaction(OER)activity due to...Two-dimensional metal dichalcogenides have been evidenced as potential electrocatalysts for hydrogen evolution reaction(HER);however,their application is limited by a poor oxygen evolution reaction(OER)activity due to insufficient number/types of multi-integrated active sites.In this study,we report a novel bifunctional catalyst developed by simultaneous engineering of single nickel atoms(Ni_(SA)) and nickel phosphate clusters(Ni_(Pi)) to synergistically trigger surface-functionalized MoS_(2) nanosheets(NSs)resulting in high reactivities for both HER and OER.The Ni_(SA)-Ni_(Pi)/MoS_(2)NSs material exhibits a fairly Pt-like HER behavior with an overpotential of 94.0 mV and a small OER overpotential of 314.0 mV to reach 10 mA cm^(-2) in freshwater containing 1.0 M KOH.Experimental results of the catalyst are well supported by theoretical study,which reveals the significant modulation of electronic structure and enrichment of electroactive site number/types with their reasonably adjusted free adsorption energy.For evaluating practicability,the Ni_(SA)-Ni_(Pi)/MoS_(2)NSs-based electrolyzer delivers effective operation voltage of 1.62,1.52,and 1.66 V at 10 mA cm^(-2) and superior long-term stability as compared to Pt/C//RuO_(2) system in freshwater,mimic seawater,and natural seawater,respectively.The present study indicates that the catalyst is a promising candidate for the practical production of green hydrogen via water electrolysis.展开更多
[Objectives]To establish an HPLC method for the quantitative determination of multiple phenolic acid components in Tetracera asiatica medicinal material,providing a basis for establishing its quality standards.[Method...[Objectives]To establish an HPLC method for the quantitative determination of multiple phenolic acid components in Tetracera asiatica medicinal material,providing a basis for establishing its quality standards.[Methods]An Inertsil ODS-C 18 column(250 mm×4.6 mm,5μm)was used.The mobile phase consisted of acetonitrile-0.2% phosphoric acid solution(10:90).The flow rate was 1.0 mL/min.The detection wavelength was 274 nm.The column temperature was 25℃.The injection volume was 10μL.The content of three components,gallic acid,protocatechuic acid,and protocatechualdehyde,was determined in 13 batches of T.asiatica.[Results]Gallic acid showed good linearity within the range of 0.020-6.400μg/mL,protocatechuic acid within 0.201-6.432μg/mL,and protocatechualdehyde within 0.202-6.464μg/mL(r>0.9990).The average recovery rates ranged from 98.61%to 101.17%,with RSD s between 1.21%and 2.69%.[Conclusions]The quantitative determination method established in this study is simple and feasible,and can provide a basis for the quality evaluation of T.asiatica.展开更多
Fiber reinforcement significantly enhances the strength,toughness,and durability of concrete by reducing the propagation of microcracks in the concrete matrix.With the rising demand for high-performance concrete(HPC),...Fiber reinforcement significantly enhances the strength,toughness,and durability of concrete by reducing the propagation of microcracks in the concrete matrix.With the rising demand for high-performance concrete(HPC),this study investigates the mechanical properties of HPC with varying proportions of polypropylene(PP)and steel(ST)fibers.Supplementary cementitious materials(SCMs)toward partial replacement of ordinary Portland cement(OPC)were incorporated to prepare HPC mixes as a ternary composite system using Fly Ash(FA),Silica Fume(SF),and Ground Granulated Blast Furnace Slag(GGBS).Each HPC mix comprised two SCMs,accounting for 20%of the mass fraction of the OPC binder.The study encompassed fiber percentages ranging from 0 to 0.075%PP and 0 to 2%ST,incorporating them into the HPC mixes with gradual increases of 0.025%for PP and 0.5%for ST fiber by mass fraction.All HPC mixes were tested for mechanical properties using compressive and split tensile strength tests.The influence of SCMs on HPC was studied using X-ray diffraction(XRD)for microstructural analyses.It was found that the compressive and split tensile strengths of HPC increased up to an optimal fiber percentage and then decreased.A comparison of the test results of high-performance fiber-reinforced concrete with those of plain HPC revealed significant improvements in compressive and splitting tensile strengths by 26.59%and 57.74%,respectively.Also,the XRD analysis revealed that the composition of the SCMs in HPC was a significant and effective solution for the mechanical properties of the concrete.展开更多
Covalent organic frameworks(COFs)have demonstrated great potential in chromatographic separation because of unique structure and superior performance.Herein,single-crystal three-dimensional(3D)COFs with regular morpho...Covalent organic frameworks(COFs)have demonstrated great potential in chromatographic separation because of unique structure and superior performance.Herein,single-crystal three-dimensional(3D)COFs with regular morphology,good monodispersity and high specific surface area,were used as a stationary phase for high-performance liquid chromatography(HPLC).The single-crystal 3D COFs packed column not only exhibits high efficiency in separating hydrophobic molecules involving substituted benzenes,halogenated benzenes,halogenated nitrobenzenes,aromatic amines,aromatic hydrocarbons(PAHs)and phthalate esters(PAEs),but also achieves baseline separation of acenaphthene and acenaphthylene with similar physical and chemical properties as well as environmental pollutants,which cannot be quickly separated on commercial C18 column and a polycrystalline 3D COFs packed column.Especially,the column efficiency of 17303-24255 plates/m was obtained for PAEs,and the resolution values for acenaphthene and acenaphthylene,and carbamazepine(CBZ)and carbamazepine-10,11-epoxide(CBZEP)were 1.7and 2.2,respectively.This successful application not only confirmed the great potential of the singlecrystal 3D COFs in HPLC separation of the organic molecules,but also facilitates the application of COFs in separation science.展开更多
Compared to subtractive manufacturing and casting,3D printing(additive manufacturing)offers advantages,such as the rapid production of complex structures,reduced material waste,and environmental friendliness.Direct in...Compared to subtractive manufacturing and casting,3D printing(additive manufacturing)offers advantages,such as the rapid production of complex structures,reduced material waste,and environmental friendliness.Direct ink writing(DIW)is one of the most popular 3D printing techniques owing to its ability to print multiple materials simultaneously and its high compatibility with printing inks.However,DIW presents significant challenges,particularly in the printing of high-performance polymers.The main challenges are as follows:1.The rigid structures and reaction kinetics of high-performance polymers make developing new inks difficult.2.The limited types of available high-performance polymers underscore the need for new DIW-suitable materials.3.Layer-by-layer stacking weakens interlayer bonding,affecting the mechanical properties of the printed product.4.The accuracy and speed of DIW printing are insufficient for large-scale manufacturing.After introducing the topic,the requirements for DIW printing inks are first reviewed,emphasizing the importance of thixotropic agents.Then,research progress regarding DIW printing of high-performance polymers is comprehensively reviewed according to the requirements of different polymer inks.Additionally,the applications of these materials across various fields are summarized.Finally,the challenges in DIW printing of high-performance polymers,along with corresponding solutions and future development prospects,are discussed in detail.展开更多
As electronic devices continue to evolve toward higher power densities,faster speeds,and smaller form factors,the demand for high-performance electronic packaging materials has become increasingly critical.These mater...As electronic devices continue to evolve toward higher power densities,faster speeds,and smaller form factors,the demand for high-performance electronic packaging materials has become increasingly critical.These materials serve as the physical and functional interface between semiconductor components and their operating environment,impacting the overall reliability,thermal management,mechanical protection,and electrical performance of modern electronic systems.This study investigates the development,formulation,and performance evaluation of advanced packaging materials,focusing on polymer-based composites,metal and ceramic matrix systems,and nanomaterial-enhanced formulations.A comprehensive analysis of key performance metrics-including thermal conductivity,electrical insulation,mechanical robustness,and environmental resistance-is presented,alongside strategies for material optimization through interface engineering and processing innovations.Furthermore,the study explores cutting-edge integration technologies such as 3D packaging compatibility,low-temperature co-firing,and high-density interconnects.The findings provide critical insights into the structure-property-processing relationships that define the effectiveness of next-generation packaging materials and offer a roadmap for material selection and system integration in high-reliability electronic applications.展开更多
Exploring platinum single-atom electrocatalysts(SACs)is of great significance for effectively catalyzing the hydrogen evolution reaction in order to maximize the utilization of metal atoms.Herein,ruthenium clusters wi...Exploring platinum single-atom electrocatalysts(SACs)is of great significance for effectively catalyzing the hydrogen evolution reaction in order to maximize the utilization of metal atoms.Herein,ruthenium clusters with several atoms(Rux)supported on nitrogen-doped,cost-efficient Black Pearls 2000(Ru_(x)NBP),were synthesized as initial materials via a simple hydrothermal method.Then,[PtCl_(4)]^(2–)ion was reductively deposited on RuxNBP to obtain a Pt SAC(Pt1/RuxNBP).Electrochemical measurements demonstrate the excellent HER performance of Pt_(1)/Ru_(x)NBP with a 5.7-fold increase in mass activity compared to the commercial Pt/C at 20 mV.Moreover,the cell voltage of the proton exchange membrane electrolyzer with Pt_(1)/Ru_(x)NBP is 20 mV lower compared to that with commercial Pt/C at 1.0 A cm^(−2).Physical characterization and density functional theory calculations revealed that the preserved Pt–Cl bond of[PtCl_(4)]^(2–)and the RuxNBP support co-regulate the 5d state of isolated Pt atoms and enhance the catalytic HER capacity of Pt1/RuxNBP.展开更多
Incorporating low-concentration precious metals into transition metal phosphides(TMPs)may represent a promising strategy to achieve improved catalytic performance of oxygen evolution reaction(OER).We design RuP_(4)clu...Incorporating low-concentration precious metals into transition metal phosphides(TMPs)may represent a promising strategy to achieve improved catalytic performance of oxygen evolution reaction(OER).We design RuP_(4)clusters immobilized on porous NiFeP nanosheets with Ru-P/O-TM bridge(RuP-NiFeP)for effective OER.The Ru-P/O-Ni/Fe bridges formed between the RuP_(4)clusters and the NiFeP facilitate electron transfer between oxyphilic Ru atoms and Ni/Fe atoms,enabling Ru to achieve optimized reactant/intermediate adsorption.Advanced characterizations and theoretical calculations reveal that the incorporation of Ru species leads to the upshift of d band center and the formation of more disorderedγ-NiOOH.The Ru-based clusters and the achieved disorderedγ-NiOOH may deliver synergistic effect to further enhance the OER capability of RuP-NiFeP.Moreover,the presence of Ru species shifts the OER mechanism from the absorbate evolution mechanism(AEM)pathway(NiFeP)to the lattice oxygen mechanism(LOM)pathway,with*OH deprotonation(*OH→*O)as the rate-determining step(RDS).The RuP-NiFeP catalyst exhibits remarkable alkaline OER activity,requiring only an overpotential of 225 mV to achieve a current density of 100 mA cm^(−2),and retains its performance with a minimal current density decay of 1.9%after stability test.This work offers valuable insights into the design of cost-effective and highly efficient electrocatalysts for alkaline OER.展开更多
Under hydrothermal and solvothermal conditions,two novel cobalt-based complexes,{[Co_(2)(CIA)(OH)(1,4-dtb)]·3.2H_(2)O}n(HU23)and{[Co_(2)(CIA)(OH)(1,4-dib)]·3.5H2O·DMF}n(HU24),were successfully construct...Under hydrothermal and solvothermal conditions,two novel cobalt-based complexes,{[Co_(2)(CIA)(OH)(1,4-dtb)]·3.2H_(2)O}n(HU23)and{[Co_(2)(CIA)(OH)(1,4-dib)]·3.5H2O·DMF}n(HU24),were successfully constructed by coordinatively assembling the semi-rigid multidentate ligand 5-(1-carboxyethoxy)isophthalic acid(H₃CIA)with the Nheterocyclic ligands 1,4-di(4H-1,2,4-triazol-4-yl)benzene(1,4-dtb)and 1,4-di(1H-imidazol-1-yl)benzene(1,4-dib),respectively,around Co^(2+)ions.Single-crystal X-ray diffraction analysis revealed that in both complexes HU23 and HU24,the CIA^(3-)anions adopt aκ^(7)-coordination mode,bridging six Co^(2+)ions via their five carboxylate oxygen atoms and one ether oxygen atom.This linkage forms tetranuclear[Co4(μ3-OH)2]^(6+)units.These Co-oxo cluster units were interconnected by CIA^(3-)anions to assemble into 2D kgd-type structures featuring a 3,6-connected topology.The 2D layers were further connected by 1,4-dtb and 1,4-dib,resulting in 3D pillar-layered frameworks for HU23 and HU24.Notably,despite the similar configurations of 1,4-dtb and 1,4-dib,differences in their coordination spatial orientations lead to topological divergence in the 3D frameworks of HU23 and HU24.Topological analysis indicates that the frameworks of HU23 and HU24 can be simplified into a 3,10-connected net(point symbol:(4^(10).6^(3).8^(2))(4^(3))_(2))and a 3,8-connected tfz-d net(point symbol:(4^(3))_(2)((4^(6).6^(18).8^(4)))),respectively.This structural differentiation confirms the precise regulatory role of ligands on the topology of metal-organic frameworks.Moreover,the ultraviolet-visible absorption spectra confirmed that HU23 and HU24 have strong absorption capabilities for ultraviolet and visible light.According to the Kubelka-Munk method,their bandwidths were 2.15 and 2.08 eV,respectively,which are consistent with those of typical semiconductor materials.Variable-temperature magnetic susceptibility measurements(2-300 K)revealed significant antiferromagnetic coupling in both complexes,with their effective magnetic moments decreasing markedly as the temperature lowered.CCDC:2457554,HU23;2457553,HU24.展开更多
As large-scale astronomical surveys,such as the Sloan Digital Sky Survey(SDSS)and the Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST),generate increasingly complex datasets,clustering algorithms have...As large-scale astronomical surveys,such as the Sloan Digital Sky Survey(SDSS)and the Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST),generate increasingly complex datasets,clustering algorithms have become vital for identifying patterns and classifying celestial objects.This paper systematically investigates the application of five main categories of clustering techniques-partition-based,density-based,model-based,hierarchical,and“others”-across a range of astronomical research over the past decade.This review focuses on the six key application areas of stellar classification,galaxy structure analysis,detection of galactic and interstellar features,highenergy astrophysics,exoplanet studies,and anomaly detection.This paper provides an in-depth analysis of the performance and results of each method,considering their respective suitabilities for different data types.Additionally,it presents clustering algorithm selection strategies based on the characteristics of the spectroscopic data being analyzed.We highlight challenges such as handling large datasets,the need for more efficient computational tools,and the lack of labeled data.We also underscore the potential of unsupervised and semi-supervised clustering approaches to overcome these challenges,offering insight into their practical applications,performance,and results in astronomical research.展开更多
Bottom-up and top-down endogenous automobile clusters exhibit distinct evolutionary traits and driving mechanisms,yet their comparative analysis remains understudied.Therefore,using Taizhou automobile industry cluster...Bottom-up and top-down endogenous automobile clusters exhibit distinct evolutionary traits and driving mechanisms,yet their comparative analysis remains understudied.Therefore,using Taizhou automobile industry cluster(TAIC)and Wuhu automobile industry cluster(WAIC)as cases,using historical statistical data and field interview data from the 1980s to 2023,combined with qualitative research methods of thematic and diachronic analysis,and quantitative research methods of social network analysis,we compare both endogenous automobile clusters’evolutionary traits and driving mechanisms.The results confirm both clusters undergo multi-scale spatial reconfiguration,organizational complexification,and intelligent networking technological transformation,yet diverge fundamentally:TAIC evolves through market-driven progressive expansion,transitioning from single to dual-core structures via private enterprise networking,with innovation following market-integrated logic and institutional thickness built on demand-driven evolution.Conversely,WAIC follows planned expansion,maintaining state-led hierarchical single-core stability through policy-driven breakthrough innovation and supply-dominated institutional construction-though both ultimately require formal-informal system synergy.Their coevolution is driven by dynamic interactions of path dependence(weakening influence),learning-innovation(strengthening influence),and relationship selection(inverted U-shaped trajectory),with divergent development paths rooted in TAIC’s grassroots self-organization genes versus WAIC’s top-level design genes,amplified by core enterprises’strategic disparities.The research findings can not only provide decision-making support for China’s industrial upgrading,but also contribute China’s insights to global economic governance.展开更多
This paper proposes an equivalent modeling method for photovoltaic(PV)power stations via a particle swarm optimization(PSO)K-means clustering(KMC)algorithm with passive filter parameter clustering to address the compl...This paper proposes an equivalent modeling method for photovoltaic(PV)power stations via a particle swarm optimization(PSO)K-means clustering(KMC)algorithm with passive filter parameter clustering to address the complexities,simulation time cost and convergence problems of detailed PV power station models.First,the amplitude–frequency curves of different filter parameters are analyzed.Based on the results,a grouping parameter set for characterizing the external filter characteristics is established.These parameters are further defined as clustering parameters.A single PV inverter model is then established as a prerequisite foundation.The proposed equivalent method combines the global search capability of PSO with the rapid convergence of KMC,effectively overcoming the tendency of KMC to become trapped in local optima.This approach enhances both clustering accuracy and numerical stability when determining equivalence for PV inverter units.Using the proposed clustering method,both a detailed PV power station model and an equivalent model are developed and compared.Simulation and hardwarein-loop(HIL)results based on the equivalent model verify that the equivalent method accurately represents the dynamic characteristics of PVpower stations and adapts well to different operating conditions.The proposed equivalent modeling method provides an effective analysis tool for future renewable energy integration research.展开更多
Villager Pan Chunlin is witnessing a boom in his homestay business.More and more visitors are coming to his village,Yucun Village in Anji County,Huzhou City,Zhejiang Province.
The shift toward specialized and large-scale agricultural production has spurred the emergence of agricultural clusters as key forces of rural vitalization and sustainable development.This paper explored the formation...The shift toward specialized and large-scale agricultural production has spurred the emergence of agricultural clusters as key forces of rural vitalization and sustainable development.This paper explored the formation and evolution of Meizhou pomelo industry cluster in China,focusing on its role in restructuring rural socio-economic systems and integrating the whole value chains.Based on a case study employing qualitative methods such as in-depth interviews and participatory observation,the agricultural cluster evolution of Meizhou pomelo was categorized into three key phases of initial decentralization,self-organized scaling,and reorganized clustering.Geographical proximity and industrial agglomeration constitute the physical foundation,while vertical/horizontal linkages,technologic-al innovation,and policy support enhance competitiveness.Special mechanisms emerge through localized social networks,farmer co-operatives’activation,and cross-regional market expansion.The cluster’s impact is manifested in the shift from extensive to standard-ized and modernized production,diversified and flexible livelihood of farmers,and the integration of agriculture with industry and ser-vices.The development of the whole value chain based on agricultural cluster represents a critical pathway for achieving agricultural modernization,encompassing both internal and external value chain optimization.Through quality assurance systems,product diversi-fication strategies,operational efficiency improvements,and brand enhancement,these clusters amplify product value propositions and market competitiveness.This systemic approach facilitates supply-demand coordination,enables resource synergies,and optimizes eco-nomic returns across the horizontal and vertical value chain.This paper argues that agricultural clusters serve as strategic catalysts for sustainable rural development by reconstructing local production systems,fostering innovation ecosystems,and aligning agricultural modernization.It contributes to debates on rural vitalization by demonstrating how agricultural clustering can reconfigure rural areas as hubs of ecological modernization,rather than mere urban peripheries.展开更多
By encouraging collaboration,attracting young entrepreneurs,and setting up village-invested enterprises,rural communities in Zhejiang Province are growing their income streams.“Over the past years,we have seen more a...By encouraging collaboration,attracting young entrepreneurs,and setting up village-invested enterprises,rural communities in Zhejiang Province are growing their income streams.“Over the past years,we have seen more and more tourists coming to our village,and their stay here has grown longer.Many even said they don’t want to leave,”Pan Chunlin,a resident of Yucun Village in Anji County of Huzhou City,east China’s Zhejiang Province,told China Today.Pan is the owner of the Chunlin Lodge,a bed&breakfast(B&B)which received more than 70,000 visitors last year,generating over RMB 4 million in revenue.展开更多
Noncohesive particle clusters are identified and tracked in turbulent flows to determine the breakdown and time evolution of cluster statistics and their implications for interscale mass transfer,which has connections...Noncohesive particle clusters are identified and tracked in turbulent flows to determine the breakdown and time evolution of cluster statistics and their implications for interscale mass transfer,which has connections to the classical turbulent energy cascade and its mass cascade counterpart running in parallel.In particular,the formation and dynamics of sediment and larvae clusters are of interest to coral larvae settlement in coastal regions and particularly the resilience of green-gray coastal protection solutions.Analogous cluster behavior is relevant to cloud microphysics and precipitation initiation,radiation transport and light transmission through colloids and suspensions,heat and mass transfer in particle-laden flows,and viral and pollutant transmission.Following a comparison between various clustering techniques,we adopt a density-based cluster identification algorithm based on its simplicity and efficiency,where particles are clustered based on the number of neighboring particles in their individual spheres of influence.We establish parallels with lattice-based percolation theory,as evident in the power-law scaling of the cluster size distribution near the percolation threshold.The degree of discontinuity of the phase transition associated with this percolation threshold is observed to broaden with larger Stokes numbers and thereby large-scale clustering.The sensitivity of our findings to the employed clustering algorithm is discussed.A novel cluster tracking algorithm is deployed to determine the interscale transfer rate along the particle-number phase-space dimension via accounting of cluster breakup and merger events,extending previous work on the bubble breakup cascade beneath surface breaking waves.Our findings shed light on the interaction between particle clusters and their carrier turbulent flows,with an eye toward transport models incorporating cluster characteristics and dynamics.展开更多
基金supported by the National Natural Science Foundation of China (Nos.22064020,22364022,and 22174125)the Applied Basic Research Foundation of Yunnan Province (Nos.202101AT070101 and 202201AT070029)。
文摘Developing a chiral material as versatile and universal chiral stationary phase(CSP) for chiral separation in diverse chromatographic techniques simultaneously is of great significance.In this study,we demonstrated for the first time that a chiral metal-organic cage(MOC),[Zn_(6)M_(4)],as a universal chiral recognition material for both multi-mode high-performance liquid chromatography(HPLC) and capillary gas chromatography(GC) enantioseparation.Two novel HPLC CSPs with different bonding arms(CSP-A with a cationic imidazolium bonding arm and CSP-B with an alkyl chain bonding arm) were prepared by clicking of functionalized chiral MOC [Zn_(6)M_(4)] onto thiolated silica via thiol-ene click chemistry.Meanwhile,a capillary GC column statically coated with the chiral MOC [Zn_(6)M_(4)] was also fabricated.The results showed that the chiral MOC exhibits excellent enantioselectivity not only in normal phase HPLC(NP-HPLC) and reversed phase(RP-HPLC) but also in GC,and various racemates were well separated,including alcohols,diols,esters,ketones,ethers,amines,and epoxides.Importantly,CSP-A and CSP-B are complementary to commercially available Chiralcel OD-H and Chiralpak AD-H columns in enantioseparation,which can separate some racemates that could not be or could not well be separated by the two widely used commercial columns,suggesting the great potential of the two prepared CSPs in enantioseparation.This work reveals that the chiral MOC is potential versatile chiral recognition materials for both HPLC and GC,and also paves the way to expand the potential applications of MOCs.
基金the financial support from the National Natural Science Foundation of China(Nos.22109164 and 22371046)the Key Program of the Natural Science Foundation of Fujian Province(No.2021J02007)。
文摘Exploring the synthesis of novel structures is crucial for the development of functional materials.In this context,a novel and intriguing 3d-5p heterometallic cluster-substituted polyoxotungstate material,H_(29)Na_(9)(H_(2)O)_(21){Ca(H_(2)O)_(2)@Sb_(12)O_(18)[Ni_(2)(OH)(A-α-Si W_(10)O_(37))]_(3)}_(2)·40H_(2)O(1),was constructed using Keggintype polyoxotungstate A-α-Si W_(10)O_(37),along with Ni and Sb elements.The structure features a Tdsymmetric Sb_(12)O_(18)({Sb_(12)})cage that encapsulates an 8-coordinate Ca^(2+)ion at its face.Additionally,the{Sb_(12)}cage forms an 18-nuclear 3d-5p heterometallic cluster by connecting with three di-nuclear nickel clusters through shared oxygen atoms.Electrochemical impedance spectra studies reveal that the single crystal of 1 achieves a proton conductivity of 1.11×10^(-1)S/cm along the[110]direction and 1.04×10^(-1)S/cm along the[100]direction at 85℃ and 98%relative humidity(RH).Furthermore,the powder form of 1 exhibits a proton conductivity of 3.00×10^(-2)S/cm.These findings suggest that compound 1 holds promise as a practical proton conducting material.
基金the support of the National Nature Science Foundation of China (21908124)Zhaoqing Xijiang Talent Program。
文摘Rational design and synthesis of low-cost trifunctional electrocatalysts with improved stability and superior electrocatalytic activity for oxygen reduction reaction(ORR),oxygen evolution reaction(OER),and hydrogen evolution reaction(HER) are highly desirable but remain as the bottlenecks at the current state of technology.In this paper,the cobalt-iron(Co-Fe) composite supported on nitrogen-doped carbon nanotubes(CoFe composite/NCNTs) is synthesized.The intrinsic OER and HER catalytic activities of this CoFe composite/NCNTs composite are significantly improved with palladium(Pd) nanocluster decoration [Pd-coated(CoFe composite/NCNTs)].The as-prepared Pd-coated(CoFe composite/NCNTs) catalyst exhibits excellent trifunctional electrocatalytic activity and stability due to the interfacial coupling between Pd and(CoFe composite/NCNTs).This catalyst is successfully employed in the water electrolysis cell as both OER and HER electrode catalysts,flexible rechargeable Zn-air battery as the bifunctional ORR and OER electrode catalyst.The cell voltage of this catalyst-coated electrodes requires only 1.60 V to achieve 10 mA cm^(-2) current density for water electrolysis cell,which is comparable to and even better than that of Pt/C and Ir/C based cell.The primary Zn-air battery using this catalyst shows a constant high open-circuit voltage(OCV) of 1.47 V and a maximum power density of 261 mW cm^(-2) in the flooded mode configuration.Most importantly,a flexible Zn-air battery with this catalyst runs very smoothly without a change in voltage gap during flat,bending,and twisting positions.
基金financially supported by the National Natural Science Foundation of China (Nos. 21471003, 21871141, 21871142,21701085 and 21901122)Natural Science Foundation of Educational Commission of Anhui Province of China (No. KJ2020A0240)+1 种基金the Natural Science Research of Jiangsu Higher Education Institutions of China (No. 19KJB150011)Project funded by China Postdoctoral Science Foundation (No. 2019M651873)。
文摘Metal-doped carbon materials, as one of the most important electrocatalytic catalysts for CO_(2)reduction reaction(CO_(2)RR), have attracted increasing attention. Herein, a series of Cu cluster embedded highly porous nanofibers have been prepared through the carbonization of electro-spun MOF/PAN nanofibers.The obtained Cu cluster doped porous nanofibers possessed fibrous morphology, high porosity, conductivity, and uniformly dispersed Cu clusters, which could be applied as promising CO_(2)RR catalysts. Specifically, best of them, MCP-500 exhibited high catalytic performance for CO_(2)RR, in which the Faradaic efficiency of CO(FECO) was as high as 98% at-0.8 V and maintained above 95% after 10 h continuous electrocatalysis. The high performance might be attributed to the synergistic effect of tremendously layered graphene skeleton and uniformly dispersed Cu clusters that could largely promote the electron conductivity, mass transfer and catalytic activity during the electrocatalytic CO_(2)RR process. This attempt will provide a new idea to design highly active CO_(2)RR electrocatalyst.
基金supported by the Regional Leading Research Center Program(2019R1A5A8080326)Basic Science Research Program(2020R1F1A1075921)BRL Program(2020R1A4A1018259)through the National Research Foundation(NRF)funded by the Ministry of Science and ICT of Republic of Korea.
文摘Two-dimensional metal dichalcogenides have been evidenced as potential electrocatalysts for hydrogen evolution reaction(HER);however,their application is limited by a poor oxygen evolution reaction(OER)activity due to insufficient number/types of multi-integrated active sites.In this study,we report a novel bifunctional catalyst developed by simultaneous engineering of single nickel atoms(Ni_(SA)) and nickel phosphate clusters(Ni_(Pi)) to synergistically trigger surface-functionalized MoS_(2) nanosheets(NSs)resulting in high reactivities for both HER and OER.The Ni_(SA)-Ni_(Pi)/MoS_(2)NSs material exhibits a fairly Pt-like HER behavior with an overpotential of 94.0 mV and a small OER overpotential of 314.0 mV to reach 10 mA cm^(-2) in freshwater containing 1.0 M KOH.Experimental results of the catalyst are well supported by theoretical study,which reveals the significant modulation of electronic structure and enrichment of electroactive site number/types with their reasonably adjusted free adsorption energy.For evaluating practicability,the Ni_(SA)-Ni_(Pi)/MoS_(2)NSs-based electrolyzer delivers effective operation voltage of 1.62,1.52,and 1.66 V at 10 mA cm^(-2) and superior long-term stability as compared to Pt/C//RuO_(2) system in freshwater,mimic seawater,and natural seawater,respectively.The present study indicates that the catalyst is a promising candidate for the practical production of green hydrogen via water electrolysis.
基金Supported by Regional Science Foundation of China,National Natural Science Foundation(No.82160820)General Program of Guizhou Provincial Natural Science Foundation[QianKeHe Foundation-ZK(2023)General153].
文摘[Objectives]To establish an HPLC method for the quantitative determination of multiple phenolic acid components in Tetracera asiatica medicinal material,providing a basis for establishing its quality standards.[Methods]An Inertsil ODS-C 18 column(250 mm×4.6 mm,5μm)was used.The mobile phase consisted of acetonitrile-0.2% phosphoric acid solution(10:90).The flow rate was 1.0 mL/min.The detection wavelength was 274 nm.The column temperature was 25℃.The injection volume was 10μL.The content of three components,gallic acid,protocatechuic acid,and protocatechualdehyde,was determined in 13 batches of T.asiatica.[Results]Gallic acid showed good linearity within the range of 0.020-6.400μg/mL,protocatechuic acid within 0.201-6.432μg/mL,and protocatechualdehyde within 0.202-6.464μg/mL(r>0.9990).The average recovery rates ranged from 98.61%to 101.17%,with RSD s between 1.21%and 2.69%.[Conclusions]The quantitative determination method established in this study is simple and feasible,and can provide a basis for the quality evaluation of T.asiatica.
基金financed by the Science and Engineering Research Board,India,in Project No.EEQ/2023/000130CSIR-India in Project No.MLP072002.
文摘Fiber reinforcement significantly enhances the strength,toughness,and durability of concrete by reducing the propagation of microcracks in the concrete matrix.With the rising demand for high-performance concrete(HPC),this study investigates the mechanical properties of HPC with varying proportions of polypropylene(PP)and steel(ST)fibers.Supplementary cementitious materials(SCMs)toward partial replacement of ordinary Portland cement(OPC)were incorporated to prepare HPC mixes as a ternary composite system using Fly Ash(FA),Silica Fume(SF),and Ground Granulated Blast Furnace Slag(GGBS).Each HPC mix comprised two SCMs,accounting for 20%of the mass fraction of the OPC binder.The study encompassed fiber percentages ranging from 0 to 0.075%PP and 0 to 2%ST,incorporating them into the HPC mixes with gradual increases of 0.025%for PP and 0.5%for ST fiber by mass fraction.All HPC mixes were tested for mechanical properties using compressive and split tensile strength tests.The influence of SCMs on HPC was studied using X-ray diffraction(XRD)for microstructural analyses.It was found that the compressive and split tensile strengths of HPC increased up to an optimal fiber percentage and then decreased.A comparison of the test results of high-performance fiber-reinforced concrete with those of plain HPC revealed significant improvements in compressive and splitting tensile strengths by 26.59%and 57.74%,respectively.Also,the XRD analysis revealed that the composition of the SCMs in HPC was a significant and effective solution for the mechanical properties of the concrete.
基金the National Natural Science Foundation of China(No.22274021)Natural Science Foundation of Fujian Province(No.2022J01535)for financial support。
文摘Covalent organic frameworks(COFs)have demonstrated great potential in chromatographic separation because of unique structure and superior performance.Herein,single-crystal three-dimensional(3D)COFs with regular morphology,good monodispersity and high specific surface area,were used as a stationary phase for high-performance liquid chromatography(HPLC).The single-crystal 3D COFs packed column not only exhibits high efficiency in separating hydrophobic molecules involving substituted benzenes,halogenated benzenes,halogenated nitrobenzenes,aromatic amines,aromatic hydrocarbons(PAHs)and phthalate esters(PAEs),but also achieves baseline separation of acenaphthene and acenaphthylene with similar physical and chemical properties as well as environmental pollutants,which cannot be quickly separated on commercial C18 column and a polycrystalline 3D COFs packed column.Especially,the column efficiency of 17303-24255 plates/m was obtained for PAEs,and the resolution values for acenaphthene and acenaphthylene,and carbamazepine(CBZ)and carbamazepine-10,11-epoxide(CBZEP)were 1.7and 2.2,respectively.This successful application not only confirmed the great potential of the singlecrystal 3D COFs in HPLC separation of the organic molecules,but also facilitates the application of COFs in separation science.
基金supported by National Key Research and Development Program of China(Grant No.2022YFB3809000)Major Science and Technology Project of Gansu Province(Grant No.23ZDGA011)+1 种基金National Natural Science Foundation of China(Grant No.22275199,52105224)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB04701022021).
文摘Compared to subtractive manufacturing and casting,3D printing(additive manufacturing)offers advantages,such as the rapid production of complex structures,reduced material waste,and environmental friendliness.Direct ink writing(DIW)is one of the most popular 3D printing techniques owing to its ability to print multiple materials simultaneously and its high compatibility with printing inks.However,DIW presents significant challenges,particularly in the printing of high-performance polymers.The main challenges are as follows:1.The rigid structures and reaction kinetics of high-performance polymers make developing new inks difficult.2.The limited types of available high-performance polymers underscore the need for new DIW-suitable materials.3.Layer-by-layer stacking weakens interlayer bonding,affecting the mechanical properties of the printed product.4.The accuracy and speed of DIW printing are insufficient for large-scale manufacturing.After introducing the topic,the requirements for DIW printing inks are first reviewed,emphasizing the importance of thixotropic agents.Then,research progress regarding DIW printing of high-performance polymers is comprehensively reviewed according to the requirements of different polymer inks.Additionally,the applications of these materials across various fields are summarized.Finally,the challenges in DIW printing of high-performance polymers,along with corresponding solutions and future development prospects,are discussed in detail.
文摘As electronic devices continue to evolve toward higher power densities,faster speeds,and smaller form factors,the demand for high-performance electronic packaging materials has become increasingly critical.These materials serve as the physical and functional interface between semiconductor components and their operating environment,impacting the overall reliability,thermal management,mechanical protection,and electrical performance of modern electronic systems.This study investigates the development,formulation,and performance evaluation of advanced packaging materials,focusing on polymer-based composites,metal and ceramic matrix systems,and nanomaterial-enhanced formulations.A comprehensive analysis of key performance metrics-including thermal conductivity,electrical insulation,mechanical robustness,and environmental resistance-is presented,alongside strategies for material optimization through interface engineering and processing innovations.Furthermore,the study explores cutting-edge integration technologies such as 3D packaging compatibility,low-temperature co-firing,and high-density interconnects.The findings provide critical insights into the structure-property-processing relationships that define the effectiveness of next-generation packaging materials and offer a roadmap for material selection and system integration in high-reliability electronic applications.
文摘Exploring platinum single-atom electrocatalysts(SACs)is of great significance for effectively catalyzing the hydrogen evolution reaction in order to maximize the utilization of metal atoms.Herein,ruthenium clusters with several atoms(Rux)supported on nitrogen-doped,cost-efficient Black Pearls 2000(Ru_(x)NBP),were synthesized as initial materials via a simple hydrothermal method.Then,[PtCl_(4)]^(2–)ion was reductively deposited on RuxNBP to obtain a Pt SAC(Pt1/RuxNBP).Electrochemical measurements demonstrate the excellent HER performance of Pt_(1)/Ru_(x)NBP with a 5.7-fold increase in mass activity compared to the commercial Pt/C at 20 mV.Moreover,the cell voltage of the proton exchange membrane electrolyzer with Pt_(1)/Ru_(x)NBP is 20 mV lower compared to that with commercial Pt/C at 1.0 A cm^(−2).Physical characterization and density functional theory calculations revealed that the preserved Pt–Cl bond of[PtCl_(4)]^(2–)and the RuxNBP support co-regulate the 5d state of isolated Pt atoms and enhance the catalytic HER capacity of Pt1/RuxNBP.
基金supported by the Australian Research Council(DE240100868)CSIRO“International Hydrogen Research Collaboration Program-RESEARCH FELLOWSHIPS”+3 种基金the National Natural Science Foundation of China(22209103)the UTS Chancellor's Research Fellowshipssupport from the “Joint International Laboratory on Environmental and Energy Frontier Materials” and the “Innovation Research Team of High-Level Local Universities in Shanghai”Supported by Computing, Shanghai University
文摘Incorporating low-concentration precious metals into transition metal phosphides(TMPs)may represent a promising strategy to achieve improved catalytic performance of oxygen evolution reaction(OER).We design RuP_(4)clusters immobilized on porous NiFeP nanosheets with Ru-P/O-TM bridge(RuP-NiFeP)for effective OER.The Ru-P/O-Ni/Fe bridges formed between the RuP_(4)clusters and the NiFeP facilitate electron transfer between oxyphilic Ru atoms and Ni/Fe atoms,enabling Ru to achieve optimized reactant/intermediate adsorption.Advanced characterizations and theoretical calculations reveal that the incorporation of Ru species leads to the upshift of d band center and the formation of more disorderedγ-NiOOH.The Ru-based clusters and the achieved disorderedγ-NiOOH may deliver synergistic effect to further enhance the OER capability of RuP-NiFeP.Moreover,the presence of Ru species shifts the OER mechanism from the absorbate evolution mechanism(AEM)pathway(NiFeP)to the lattice oxygen mechanism(LOM)pathway,with*OH deprotonation(*OH→*O)as the rate-determining step(RDS).The RuP-NiFeP catalyst exhibits remarkable alkaline OER activity,requiring only an overpotential of 225 mV to achieve a current density of 100 mA cm^(−2),and retains its performance with a minimal current density decay of 1.9%after stability test.This work offers valuable insights into the design of cost-effective and highly efficient electrocatalysts for alkaline OER.
文摘Under hydrothermal and solvothermal conditions,two novel cobalt-based complexes,{[Co_(2)(CIA)(OH)(1,4-dtb)]·3.2H_(2)O}n(HU23)and{[Co_(2)(CIA)(OH)(1,4-dib)]·3.5H2O·DMF}n(HU24),were successfully constructed by coordinatively assembling the semi-rigid multidentate ligand 5-(1-carboxyethoxy)isophthalic acid(H₃CIA)with the Nheterocyclic ligands 1,4-di(4H-1,2,4-triazol-4-yl)benzene(1,4-dtb)and 1,4-di(1H-imidazol-1-yl)benzene(1,4-dib),respectively,around Co^(2+)ions.Single-crystal X-ray diffraction analysis revealed that in both complexes HU23 and HU24,the CIA^(3-)anions adopt aκ^(7)-coordination mode,bridging six Co^(2+)ions via their five carboxylate oxygen atoms and one ether oxygen atom.This linkage forms tetranuclear[Co4(μ3-OH)2]^(6+)units.These Co-oxo cluster units were interconnected by CIA^(3-)anions to assemble into 2D kgd-type structures featuring a 3,6-connected topology.The 2D layers were further connected by 1,4-dtb and 1,4-dib,resulting in 3D pillar-layered frameworks for HU23 and HU24.Notably,despite the similar configurations of 1,4-dtb and 1,4-dib,differences in their coordination spatial orientations lead to topological divergence in the 3D frameworks of HU23 and HU24.Topological analysis indicates that the frameworks of HU23 and HU24 can be simplified into a 3,10-connected net(point symbol:(4^(10).6^(3).8^(2))(4^(3))_(2))and a 3,8-connected tfz-d net(point symbol:(4^(3))_(2)((4^(6).6^(18).8^(4)))),respectively.This structural differentiation confirms the precise regulatory role of ligands on the topology of metal-organic frameworks.Moreover,the ultraviolet-visible absorption spectra confirmed that HU23 and HU24 have strong absorption capabilities for ultraviolet and visible light.According to the Kubelka-Munk method,their bandwidths were 2.15 and 2.08 eV,respectively,which are consistent with those of typical semiconductor materials.Variable-temperature magnetic susceptibility measurements(2-300 K)revealed significant antiferromagnetic coupling in both complexes,with their effective magnetic moments decreasing markedly as the temperature lowered.CCDC:2457554,HU23;2457553,HU24.
基金supported by the National Natural Science Foundation of China (12473105 and 12473106)the central government guides local funds for science and technology development (YDZJSX2024D049)the Graduate Student Practice and Innovation Program of Shanxi Province (2024SJ313)
文摘As large-scale astronomical surveys,such as the Sloan Digital Sky Survey(SDSS)and the Large Sky Area Multi-Object Fiber Spectroscopic Telescope(LAMOST),generate increasingly complex datasets,clustering algorithms have become vital for identifying patterns and classifying celestial objects.This paper systematically investigates the application of five main categories of clustering techniques-partition-based,density-based,model-based,hierarchical,and“others”-across a range of astronomical research over the past decade.This review focuses on the six key application areas of stellar classification,galaxy structure analysis,detection of galactic and interstellar features,highenergy astrophysics,exoplanet studies,and anomaly detection.This paper provides an in-depth analysis of the performance and results of each method,considering their respective suitabilities for different data types.Additionally,it presents clustering algorithm selection strategies based on the characteristics of the spectroscopic data being analyzed.We highlight challenges such as handling large datasets,the need for more efficient computational tools,and the lack of labeled data.We also underscore the potential of unsupervised and semi-supervised clustering approaches to overcome these challenges,offering insight into their practical applications,performance,and results in astronomical research.
基金Under the auspices of National Natural Science Foundation of China(No.42571219)Key Project of Zhejiang Province Soft Science Research Plan(No.2023C25014)。
文摘Bottom-up and top-down endogenous automobile clusters exhibit distinct evolutionary traits and driving mechanisms,yet their comparative analysis remains understudied.Therefore,using Taizhou automobile industry cluster(TAIC)and Wuhu automobile industry cluster(WAIC)as cases,using historical statistical data and field interview data from the 1980s to 2023,combined with qualitative research methods of thematic and diachronic analysis,and quantitative research methods of social network analysis,we compare both endogenous automobile clusters’evolutionary traits and driving mechanisms.The results confirm both clusters undergo multi-scale spatial reconfiguration,organizational complexification,and intelligent networking technological transformation,yet diverge fundamentally:TAIC evolves through market-driven progressive expansion,transitioning from single to dual-core structures via private enterprise networking,with innovation following market-integrated logic and institutional thickness built on demand-driven evolution.Conversely,WAIC follows planned expansion,maintaining state-led hierarchical single-core stability through policy-driven breakthrough innovation and supply-dominated institutional construction-though both ultimately require formal-informal system synergy.Their coevolution is driven by dynamic interactions of path dependence(weakening influence),learning-innovation(strengthening influence),and relationship selection(inverted U-shaped trajectory),with divergent development paths rooted in TAIC’s grassroots self-organization genes versus WAIC’s top-level design genes,amplified by core enterprises’strategic disparities.The research findings can not only provide decision-making support for China’s industrial upgrading,but also contribute China’s insights to global economic governance.
基金supported by the Research Project of China Southern Power Grid(No.056200KK52222031).
文摘This paper proposes an equivalent modeling method for photovoltaic(PV)power stations via a particle swarm optimization(PSO)K-means clustering(KMC)algorithm with passive filter parameter clustering to address the complexities,simulation time cost and convergence problems of detailed PV power station models.First,the amplitude–frequency curves of different filter parameters are analyzed.Based on the results,a grouping parameter set for characterizing the external filter characteristics is established.These parameters are further defined as clustering parameters.A single PV inverter model is then established as a prerequisite foundation.The proposed equivalent method combines the global search capability of PSO with the rapid convergence of KMC,effectively overcoming the tendency of KMC to become trapped in local optima.This approach enhances both clustering accuracy and numerical stability when determining equivalence for PV inverter units.Using the proposed clustering method,both a detailed PV power station model and an equivalent model are developed and compared.Simulation and hardwarein-loop(HIL)results based on the equivalent model verify that the equivalent method accurately represents the dynamic characteristics of PVpower stations and adapts well to different operating conditions.The proposed equivalent modeling method provides an effective analysis tool for future renewable energy integration research.
文摘Villager Pan Chunlin is witnessing a boom in his homestay business.More and more visitors are coming to his village,Yucun Village in Anji County,Huzhou City,Zhejiang Province.
基金Under the auspices of the Key Projects of Philosophy and Social Sciences Research,Ministry of Education of China(No.23JZD008)National Natural Science Foundation of China(No.42171193)+2 种基金Key Project of Guangdong Provincial Philosophy and Social Sciences Planning(No.GD24ES013,GD25ZX04)2025 Guangzhou Basic and Applied Basic Research Special Project(No.2025A04J7127)Fundamental Research Funds for the Central Universities,Sun Yat-sen University(No.24wkjc11)。
文摘The shift toward specialized and large-scale agricultural production has spurred the emergence of agricultural clusters as key forces of rural vitalization and sustainable development.This paper explored the formation and evolution of Meizhou pomelo industry cluster in China,focusing on its role in restructuring rural socio-economic systems and integrating the whole value chains.Based on a case study employing qualitative methods such as in-depth interviews and participatory observation,the agricultural cluster evolution of Meizhou pomelo was categorized into three key phases of initial decentralization,self-organized scaling,and reorganized clustering.Geographical proximity and industrial agglomeration constitute the physical foundation,while vertical/horizontal linkages,technologic-al innovation,and policy support enhance competitiveness.Special mechanisms emerge through localized social networks,farmer co-operatives’activation,and cross-regional market expansion.The cluster’s impact is manifested in the shift from extensive to standard-ized and modernized production,diversified and flexible livelihood of farmers,and the integration of agriculture with industry and ser-vices.The development of the whole value chain based on agricultural cluster represents a critical pathway for achieving agricultural modernization,encompassing both internal and external value chain optimization.Through quality assurance systems,product diversi-fication strategies,operational efficiency improvements,and brand enhancement,these clusters amplify product value propositions and market competitiveness.This systemic approach facilitates supply-demand coordination,enables resource synergies,and optimizes eco-nomic returns across the horizontal and vertical value chain.This paper argues that agricultural clusters serve as strategic catalysts for sustainable rural development by reconstructing local production systems,fostering innovation ecosystems,and aligning agricultural modernization.It contributes to debates on rural vitalization by demonstrating how agricultural clustering can reconfigure rural areas as hubs of ecological modernization,rather than mere urban peripheries.
文摘By encouraging collaboration,attracting young entrepreneurs,and setting up village-invested enterprises,rural communities in Zhejiang Province are growing their income streams.“Over the past years,we have seen more and more tourists coming to our village,and their stay here has grown longer.Many even said they don’t want to leave,”Pan Chunlin,a resident of Yucun Village in Anji County of Huzhou City,east China’s Zhejiang Province,told China Today.Pan is the owner of the Chunlin Lodge,a bed&breakfast(B&B)which received more than 70,000 visitors last year,generating over RMB 4 million in revenue.
文摘Noncohesive particle clusters are identified and tracked in turbulent flows to determine the breakdown and time evolution of cluster statistics and their implications for interscale mass transfer,which has connections to the classical turbulent energy cascade and its mass cascade counterpart running in parallel.In particular,the formation and dynamics of sediment and larvae clusters are of interest to coral larvae settlement in coastal regions and particularly the resilience of green-gray coastal protection solutions.Analogous cluster behavior is relevant to cloud microphysics and precipitation initiation,radiation transport and light transmission through colloids and suspensions,heat and mass transfer in particle-laden flows,and viral and pollutant transmission.Following a comparison between various clustering techniques,we adopt a density-based cluster identification algorithm based on its simplicity and efficiency,where particles are clustered based on the number of neighboring particles in their individual spheres of influence.We establish parallels with lattice-based percolation theory,as evident in the power-law scaling of the cluster size distribution near the percolation threshold.The degree of discontinuity of the phase transition associated with this percolation threshold is observed to broaden with larger Stokes numbers and thereby large-scale clustering.The sensitivity of our findings to the employed clustering algorithm is discussed.A novel cluster tracking algorithm is deployed to determine the interscale transfer rate along the particle-number phase-space dimension via accounting of cluster breakup and merger events,extending previous work on the bubble breakup cascade beneath surface breaking waves.Our findings shed light on the interaction between particle clusters and their carrier turbulent flows,with an eye toward transport models incorporating cluster characteristics and dynamics.
