Multiscale structures require excellent multiphysical properties to withstand the loads in various complex engineering fields.In this study,a concurrent isogeometric topology optimization method is proposed to design ...Multiscale structures require excellent multiphysical properties to withstand the loads in various complex engineering fields.In this study,a concurrent isogeometric topology optimization method is proposed to design multiscale structures with high thermal conductivity and low mechanical compliance.First,the mathematical description model of multi-objective topology optimization for multiscale structures is constructed,and a single-objective concurrent isogeometric topology optimization formulation for mechanical and thermal compliance is proposed.Then,by combining the isogeometric analysis method,the material interpolation model and decoupled sensitivity analysis scheme of the objective function are established on macro and micro scales.The solid isotropic material with penalization method is employed to update iteratively the macro and microstructure topologies simultaneously.Finally,the feasibility and advantages of the proposed approach are illustrated by several 2D and 3D numerical examples with different volume fractions,while the effects of volume fraction and different boundary conditions on the final configuration and multi-objective performance of the multiscale structure are explored.Results show that the isogeometric concurrent design of multiscale structures through multi-objective optimization can produce better multi-objective performance compared with a single-scale one.展开更多
The suprachiasmatic nucleus in the hypothalamus is the master circadian clock in mammals,coordinating physiological processes with the 24-hour day–night cycle.Comprising various cell types,the suprachiasmatic nucleus...The suprachiasmatic nucleus in the hypothalamus is the master circadian clock in mammals,coordinating physiological processes with the 24-hour day–night cycle.Comprising various cell types,the suprachiasmatic nucleus(SCN)integrates environmental signals to maintain complex and robust circadian rhythms.Understanding the complexity and synchrony within SCN neurons is essential for effective circadian clock function.Synchrony involves coordinated neuronal firing for robust rhythms,while complexity reflects diverse activity patterns and interactions,indicating adaptability.Interestingly,the SCN retains circadian rhythms in vitro,demonstrating intrinsic rhythmicity.This study introduces the multiscale structural complexity method to analyze changes in SCN neuronal activity and complexity at macro and micro levels,based on Bagrov et al.’s approach.By examining structural complexity and local complexities across scales,we aim to understand how tetrodotoxin,a neurotoxin that inhibits action potentials,affects SCN neurons.Our method captures critical scales in neuronal interactions that traditional methods may overlook.Validation with the Goodwin model confirms the reliability of our observations.By integrating experimental data with theoretical models,this study provides new insights into the effects of tetrodotoxin(TTX)on neuronal complexities,contributing to the understanding of circadian rhythms.展开更多
Multi-scale lamellar structure significantly improves toughness of Ti_(2)AlNb based alloys,which are inher-ently brittle intermetallics,without compromising their strength.This structure was achieved through-B2-transu...Multi-scale lamellar structure significantly improves toughness of Ti_(2)AlNb based alloys,which are inher-ently brittle intermetallics,without compromising their strength.This structure was achieved through-B2-transus-forging(TBTF)combined with O+B2 two-phase region heat treatments.Various types of multi-scale lamellar structures were obtained by controlling the cooling rate after TBTF.These variations were mainly attributed to differences in the distribution,content,and size of the thick lamellar O phase and the size and crystallographic orientation of B2 grain.By analyzing the microstructural characteristics and crystallographic orientation near the crack propagation path,it was found that the crack propaga-tion resistance of thick lamellae,sub grain and grain boundaries(GBs)O phase increased sequentially,accompanied by more tortuous crack propagation path.Moreover,B2 grains with high misorientation significantly deflected the crack propagation by cleavage ridges between adjoining cleavage planes.Addi-tionally,the development of numerous secondary cleavage ridges,resulting from the transition through varying secondary cleavage planes in distinct sub B2 grains,further hindered the quick propagation of cracks.It was clarified that the cleavage planes were dominantly belonging to{110}.These findings pro-vided valuable guidance for the design of damage tolerance strategies for Ti_(2)AlNb-based intermetallics.展开更多
In this paper,we introduce a novel Multi-scale and Auto-tuned Semi-supervised Deep Subspace Clustering(MAS-DSC)algorithm,aimed at addressing the challenges of deep subspace clustering in high-dimensional real-world da...In this paper,we introduce a novel Multi-scale and Auto-tuned Semi-supervised Deep Subspace Clustering(MAS-DSC)algorithm,aimed at addressing the challenges of deep subspace clustering in high-dimensional real-world data,particularly in the field of medical imaging.Traditional deep subspace clustering algorithms,which are mostly unsupervised,are limited in their ability to effectively utilize the inherent prior knowledge in medical images.Our MAS-DSC algorithm incorporates a semi-supervised learning framework that uses a small amount of labeled data to guide the clustering process,thereby enhancing the discriminative power of the feature representations.Additionally,the multi-scale feature extraction mechanism is designed to adapt to the complexity of medical imaging data,resulting in more accurate clustering performance.To address the difficulty of hyperparameter selection in deep subspace clustering,this paper employs a Bayesian optimization algorithm for adaptive tuning of hyperparameters related to subspace clustering,prior knowledge constraints,and model loss weights.Extensive experiments on standard clustering datasets,including ORL,Coil20,and Coil100,validate the effectiveness of the MAS-DSC algorithm.The results show that with its multi-scale network structure and Bayesian hyperparameter optimization,MAS-DSC achieves excellent clustering results on these datasets.Furthermore,tests on a brain tumor dataset demonstrate the robustness of the algorithm and its ability to leverage prior knowledge for efficient feature extraction and enhanced clustering performance within a semi-supervised learning framework.展开更多
Exploiting advanced nanocomposites isochronally integrating outstanding thermal conductivity(TC)and electromagnetic interference shielding effectiveness(EMI SE)can boost the cutting-edge application of phase change ma...Exploiting advanced nanocomposites isochronally integrating outstanding thermal conductivity(TC)and electromagnetic interference shielding effectiveness(EMI SE)can boost the cutting-edge application of phase change materials.Here,we report a tiramisu-like composite(GMP),where the typical“crust-and-cheese”hierarchical structure is replicated by an innovative two-step bidirectional freezing assembly(BFA)and compressive densification.Hierarchical-aligned graphene array(G-GA)with ultralow thermal resistance is fabricated through 1st BFA and graphitization.During the 2nd BFA,the MXene-CNF crosslinking network with hydrogen-bond actions is used for encapsulating polyethylene glycol(PEG)onto the microlayers of the G-GA skeleton.Remarkably,the microlaminated GMP4 achieves a recorded TC of 34.05 W m^(-1) K^(-1),unprecedented EMI SE of 87.4 dB,and preferable enthalpy density of 179.4 J cm^(-3),along with leakage-free function,and eminent thermal durability.Furthermore,the GMP-loaded equipment is demonstrated for efficient microelectronics cooling and sustainable solar energy utilization.This work opens new avenues for multiscale designing multifunctional macro-composites,broadening the application prospects in advanced electronics and solar energy utilization systems.展开更多
Alkaline electrolytic hydrogen production has emerged as one of the most practical methods for industrial-scale hydrogen production.However,the initial hydrolysis dissociation in alkaline media impedes the hydrogen ev...Alkaline electrolytic hydrogen production has emerged as one of the most practical methods for industrial-scale hydrogen production.However,the initial hydrolysis dissociation in alkaline media impedes the hydrogen evolution reaction(HER)kinetics of commercial catalysts.To overcome this limitation,this study focuses on the development of a highly efficient electrocatalyst for alkaline HER.Ni-based intermetallic compounds exhibit remarkable catalytic activity for HER,with the NiMo alloy being among the most active catalysts in alkaline environments.Here,we designed and fabricated self-supported multiscale porous NiZn/NiMo intermetallic compounds on a metal foam substrate using a versatile dealloying method.The resulting electrode exhibits excellent HER activity,achieving an overpotential of just 204 mV at 1000 mA/cm^(2),and dem-onstrates robust long-term catalytic stability,maintaining performance at 100 mA/cm^(2) for 400 h in an alkaline electrolyte.Thesefindings underscore the potential of nanosized intermetallic compounds fabricated via a dealloying approach to deliver exceptional catalytic performance for alkaline water electrolysis.展开更多
Fine-grained sedimentary rocks have become a research focus as important reservoirs and source rocks for tight and shale oil and gas.Laminae development determines the accumulation and production of tight and shale oi...Fine-grained sedimentary rocks have become a research focus as important reservoirs and source rocks for tight and shale oil and gas.Laminae development determines the accumulation and production of tight and shale oil and gas in fine-grained rocks.However,due to the resolution limit of conventional logs,it is challenging to recognize the features of centimeter-scale laminae.To close this gap,complementary studies,including core observation,thin section,X-ray diffraction(XRD),conventional log analysis,and slabs of image logs,were conducted to unravel the centimeter-scale laminae.The laminae recognition models were built using well logs.The fine-grained rocks can be divided into laminated rocks(lamina thickness of<0.01 m),layered rocks(0.01-0.1 m),and massive rocks(no layer or layer spacing of>0.1 m)according to the laminae scale from core observations.According to the mineral superposition assemblages from thin-section observations,the laminated rocks can be further divided into binary,ternary,and multiple structures.The typical mineral components,slabs,and T2spectrum distributions of various lamina types are unraveled.The core can identify the centimeter-millimeter-scale laminae,and the thin section can identify the millimeter-micrometer-scale laminae.Furthermore,they can detect mineral types and their superposition sequence.Conventional logs can identify the meter-scale layers,whereas image logs and related slabs can identify the laminae variations at millimeter-centimeter scales.Therefore,the slab of image logs combined with thin sections can identify laminae assemblage characteristics,including the thickness and vertical assemblage.The identification and classification of lamina structure of various scales on a single well can be predicted using conventional logs,image logs,and slabs combined with thin sections.The layered rocks have better reservoir quality and oil-bearing potential than the massive and laminated rocks.The laminated rocks’binary lamina is better than the ternary and multiple layers due to the high content of felsic minerals.The abovementioned results build the prediction model for multiscale laminae structure using well logs,helping sweet spots prediction in the Permian Lucaogou Formation in the Jimusar Sag and fine-grained sedimentary rocks worldwide.展开更多
The rich accumulation of methane(CH_(4))in tectonic coal layers poses a significant obstacle to the safe and efficient extraction of coal seams and coalbed methane.Tectonic coal samples from three geologically complex...The rich accumulation of methane(CH_(4))in tectonic coal layers poses a significant obstacle to the safe and efficient extraction of coal seams and coalbed methane.Tectonic coal samples from three geologically complex regions were selected,and the main results obtained by using a variety of research tools,such as physical tests,theoretical analyses,and numerical simulations,are as follows:22.4–62.5 nm is the joint segment of pore volume,and 26.7–100.7 nm is the joint segment of pore specific surface area.In the dynamic gas production process of tectonic coal pore structure,the adsorption method of methane molecules is“solid–liquid adsorption is the mainstay,and solid–gas adsorption coexists”.Methane stored in micropores with a pore size smaller than the jointed range is defined as solid-state pores.Pores within the jointed range,which transition from micropore filling to surface adsorption,are defined as gaseous pores.Pores outside the jointed range,where solid–liquid adsorption occurs,are defined as liquid pores.The evolution of pore structure affects the methane adsorption mode,which provides basic theoretical guidance for the development of coal seam resources.展开更多
The objective of dynamical system learning tasks is to forecast the future behavior of a system by leveraging observed data.However,such systems can sometimes exhibit rigidity due to significant variations in componen...The objective of dynamical system learning tasks is to forecast the future behavior of a system by leveraging observed data.However,such systems can sometimes exhibit rigidity due to significant variations in component parameters or the presence of slow and fast variables,leading to challenges in learning.To overcome this limitation,we propose a multiscale differential-algebraic neural network(MDANN)method that utilizes Lagrangian mechanics and incorporates multiscale information for dynamical system learning.The MDANN method consists of two main components:the Lagrangian mechanics module and the multiscale module.The Lagrangian mechanics module embeds the system in Cartesian coordinates,adopts a differential-algebraic equation format,and uses Lagrange multipliers to impose constraints explicitly,simplifying the learning problem.The multiscale module converts high-frequency components into low-frequency components using radial scaling to learn subprocesses with large differences in velocity.Experimental results demonstrate that the proposed MDANN method effectively improves the learning of dynamical systems under rigid conditions.展开更多
Bulk metallic glasses(BMGs)have been developed as a means to achieve durable multiscale,nanotextured surfaces with desirable properties dictated by topography for a multitude of applications.One barrier to this achiev...Bulk metallic glasses(BMGs)have been developed as a means to achieve durable multiscale,nanotextured surfaces with desirable properties dictated by topography for a multitude of applications.One barrier to this achievement is the lack of a bridging technique between macroscale thermoplastic forming and nanoimprint lithography,which arises from the difficulty and cost of generating controlled nanostructures on complex geometries using conventional top-down approaches.This difficulty is compounded by the necessary destruction of any resulting reentrant structures during rigid demolding.We have developed a generalized method to overcome this limitation by sacrificial template imprinting using zinc oxide(ZnO)nanostructures.It is established that such structures can be grown inexpensively and quickly with tunable morphologies on a wide variety of substrates out of solution,which we exploit to generate the nanoscale portion of the multiscale pattern through this bottom-up approach.In this way,we achieve metallic structures that simultaneously demonstrate features from the macroscale down to the nanoscale,requiring only the top-down fabrication of macro/microstructured molds.Upon detachment of the formed part from the multiscale molds,the ZnO remains embedded in the surface and can be removed by etching in mild conditions to both regenerate the mold and render the surface of the BMGs nanoporous.The ability to pattern metallic surfaces in a single step on length scales from centimeters down to nanometers is a critical step toward fabricating devices with complex shapes that rely on multiscale topography for their intended functions,such as biomedical and electrochemical applications.展开更多
The development of aeroengine with a high thrust-weight ratio poses great challenges for current top-coating thermal barrier coatings (TBCs) and environmental barrier coatings (EBCs) in service. Medium/high-entropy ce...The development of aeroengine with a high thrust-weight ratio poses great challenges for current top-coating thermal barrier coatings (TBCs) and environmental barrier coatings (EBCs) in service. Medium/high-entropy ceramics are highly promising candidate material for advanced TBCs/EBCs owing to their low thermal conductivity, high melting point, high-temperature stability, and calcium–magnesium–alumino–silicate (CMAS) resistance. Most feedstock powder used for medium/high-entropy TBCs/EBCs is prepared via traditional spray drying, which cannot fully exploit the advantages of multicomponent ceramics. The density, sphericity, inner structure, and flowability of feedstock powder affect their melting state during the thermal spraying process, which strongly affects the microstructure and properties of the deposited coatings. Therefore, the deposited coatings exhibit phase segregation, amorphous phases, and microstructure defects owing to unpredictable variations in feedstock powder with random morphologies and structures. Here, the structure and properties of feedstock powder prepared by state-of-the-art granulation technologies and their influences on the deposited coatings were systematically investigated, which can provide guidance for configuration optimization of feedstock powder and the manufacturing accuracy of the deposited coating. This review aims to bridge the gap between cutting-edge ceramics and advanced engineering technologies, thus providing concrete background knowledge and crucial guidelines for designing and developing TBCs/EBCs.展开更多
Carbonyl iron absorbers(CI)face significant challenges in practical applications,such as corrosion,interface bonding failure,detachment,and high maintenance costs.Herein,we have developed intelligent self-healing tech...Carbonyl iron absorbers(CI)face significant challenges in practical applications,such as corrosion,interface bonding failure,detachment,and high maintenance costs.Herein,we have developed intelligent self-healing technology based on proactive/passive mechanisms via in situ synthesis of self-healing factors(polydopamine/benzotriazole(PDA/BTA))and physical barrier layers(SiO_(2)/1,1,1,3,3,3-hexamethyl disilazane,SiO_(2)/HMDS)to enhance corrosion resistance,while also being compatible with efficient microwave absorption characteristics.The unique multiscale structure gives full play to the utilization of the roles of each functional layer,including the intelligent self-healing features of PDA/BTA,physical shielding and spatial confinement characteristics of SiO_(2)/HMDS,and magnetic-dielectric synergistic mechanism resulted from the good impedance matching characteristics,the conduction loss,the interfacial polarization loss and natural resonance.The asfabricated composites achieved an exceptional minimum reflection loss value of-55.4 dB at 10.7 GHz and the effective absorption band of 7.6 GHz.Moreover,it still exhibits obvious self-healing and corrosion resistance characteristics after 360 h corrosion treatment,ascribed to the self-healing mechanism of PDA/BTA and the blocking intervention effect of SiO_(2)/HMDS.This work is considered to pave the way for the synthesis of high-performance magnetic absorbers,especially in enhancing their intelligent self-healing ability in corrosive environments.展开更多
Stretchable conjugated polymer films are pivotal in flexible and wearable electronics.Despite significant advancements in film stretchability through molecular engineering and multicomponent blending,these conjugated ...Stretchable conjugated polymer films are pivotal in flexible and wearable electronics.Despite significant advancements in film stretchability through molecular engineering and multicomponent blending,these conjugated polymer films often exhibit limited elastic ranges and reduced carrier mobi-lities under large strain or after cyclic stretching.These limitations hinder their application in wearable electronics.Therefore,it is imperative to reveal the mechanical fatigue mechanisms and incorporate multiple strain energy dissipation strategies to enhance elastic deformation and electrical perform-ance of stretched conjugated polymer films.In this review,we begin by introducing the typical mechanical behaviors of conjugated polymer films.Subsequently,we discuss the multiscale structural evolution under various stretching conditions based on both in-situ and ex-situ characterizations.This analysis is further related to the diverse strain energy dissipation mechanisms.We next establish the correlation between strain-induced microstructure and the electrical performance of stretched conjugated polymer films.After that,we propose to develop highly elastic conjugated polymer films by constructing stable crosslinks and promoting polymer dynamics in low-crystalline polymer films.Finally,we highlight the future opportunities for high-performance and mechanically stable devices based on stretchable conjugated polymer films.展开更多
The biased random walk on supercritical Galton–Watson trees is known to exhibit a multiscale phenomenon in the slow regime:the maximal displacement of the walk in the first n steps is of order(log n)3,whereas the typ...The biased random walk on supercritical Galton–Watson trees is known to exhibit a multiscale phenomenon in the slow regime:the maximal displacement of the walk in the first n steps is of order(log n)3,whereas the typical displacement of the walk at the n-th step is of order(log n)2.Our main result reveals another multiscale property of biased walks:the maximal potential energy of the biased walks is of order(log n)2 in contrast with its typical size,which is of order log n.The proof relies on analyzing the intricate multiscale structure of the potential energy.展开更多
Carbon nitride(C_(3)N_(4))holds great promise for photocatalytic H_(2)O_(2)production from oxygen reduction.In spite of great research efforts,they still suffer from low catalytic efficiency primarily limited by the f...Carbon nitride(C_(3)N_(4))holds great promise for photocatalytic H_(2)O_(2)production from oxygen reduction.In spite of great research efforts,they still suffer from low catalytic efficiency primarily limited by the fast recombination of photogenerated charge carriers.In this work,we report the multiscale structural engineering of C_(3)N_(4)to significantly improve its optoelectronic properties and consequently photocatalytic performance.The product consists of porous spheres with high surface areas,abundant nitrogen defects,and alkali metal doping.Under visible light irradiation,our catalyst shows a remarkable H_(2)O_(2)production rate of 3,080μmol·g^(−1)·h^(−1),which is more than 10 times higher than that of bulk C_(3)N_(4)and exceeds those of most other C_(3)N_(4)-based photocatalysts.Moreover,the catalyst exhibits great stability,and can continuously work for 15 h without obvious activity decay under visible light irradiation,eventually giving rise to a high H_(2)O_(2)concentration of ca.45 mM.展开更多
Different forms of construction materials(e.g.,paints,foams,and boards)dramatically improve the quality of life.With the increasing environmental requirements for buildings,it is necessary to develop a comprehensive s...Different forms of construction materials(e.g.,paints,foams,and boards)dramatically improve the quality of life.With the increasing environmental requirements for buildings,it is necessary to develop a comprehensive sustainable construction material that is flexible in application and exhibits excellent performance,such as fireproofing and thermal insulation.Herein,an adjustable multiform material strategy by water regulation is proposed to meet the needs of comprehensive applications and reduce environmental costs.Multiform gels are constructed based on multiscale cellulose fibers and hollow glass microspheres,with fireproofing and thermal insulation.Unlike traditional materials,this multiscale cellulose-based gel can change forms from dispersion to paste to dough by adjusting its water content,which can realize various construction forms,including paints,foams,and low-density boards according to different scenarios and corresponding needs.展开更多
The sluggish reaction kinetics of alkaline hydrogen oxidation reaction(HOR)is one of the key challenges for anion exchange membrane fuel cells(AEMFCs).To achieve robust alkaline HOR with minimized cost,we developed a ...The sluggish reaction kinetics of alkaline hydrogen oxidation reaction(HOR)is one of the key challenges for anion exchange membrane fuel cells(AEMFCs).To achieve robust alkaline HOR with minimized cost,we developed a single atom-cluster multiscale structure with isolated Pt single atoms anchored on Ru nanoclusters supported on nitrogen-doped carbon nanosheets(Pt1-Ru/NC).The well-defined structure not only provides multiple sites with varied affinity with the intermediates but also enables simultaneous modulation of different sites via interfacial interaction.In addition to weakening Ru–H bond strength,the isolated Pt sites are heavily involved in hydrogen adsorption and synergistically accelerate the Volmer step with the help of Ru sites.Furthermore,this catalyst configuration inhibits the excessive occupancy of oxygen-containing species on Ru sites and facilitates the HOR at elevated potentials.The Pt1-Ru/NC catalyst exhibits superior alkaline HOR performance with extremely high activity and excellent CO-tolerance.An AEMFC with a 0.1 mg·cmPGM^(−2)loading of Pt1-Ru/NC anode catalyst achieves a peak powder density of 1172 mW·cm^(−2),which is 2.17 and 1.55 times higher than that of Pt/C and PtRu/C,respectively.This work provides a new catalyst concept to address the sluggish kinetics of electrocatalytic reactions containing multiple intermediates and elemental steps.展开更多
A novel electrocatalyst,Ni-Co/β-Mo_(2)C@C,was rationally designed to enhance the efficiency of the hydrogen evolution reaction(HER)in this work.Assembled with two-dimensional Ni-Co nanosheets onto Mo_(2)C nanorods co...A novel electrocatalyst,Ni-Co/β-Mo_(2)C@C,was rationally designed to enhance the efficiency of the hydrogen evolution reaction(HER)in this work.Assembled with two-dimensional Ni-Co nanosheets onto Mo_(2)C nanorods coated with a thin carbon shell,the catalyst demonstrates remarkable performance,including low overpotential(η_(10)=57 mV)and reduced Tafel slope(63 mV·dec^(–1))in 0.5 mol·L^(–1)H_(2)SO_(4) electrolyte.This innovative design strategy provides abundant active sites and efficient electron/ion transport pathways,effectively shortening reactant diffusion distances and enhancing electrocatalytic activity.Additionally,the carbon shell coating protects the catalyst from etching and agglomeration,ensuring its durability.This work presents a promising approach for engineering highly efficient metal carbide-based HER catalysts through tailored composition and nanostructure design.展开更多
Turbulence is a century-old physics problem,and the prediction of laminar-turbulent transition remains a major challenge in computational fluid dynamics(CFD).This paper proposes a new conceptual multiscale-structure f...Turbulence is a century-old physics problem,and the prediction of laminar-turbulent transition remains a major challenge in computational fluid dynamics(CFD).This paper proposes a new conceptual multiscale-structure flow system consisting of a nonturbulent part and two types of turbulent eddies with different properties.The stability criterion for turbulent transition flows,based on the principle of compromise-in-competition between viscosity and inertia,is used to obtain model closure.The multiscale-structure concept and stability criterion are the characteristics of the dual-eddy energy-minimization multiscale(EMMS)-based turbulence model.The solved heterogeneous structure parameters and energy dissipation rate are analyzed,which reveal the laminar-turbulent transition process.To validate the dual-eddy EMMS-based turbulence model,three benchmark problems,namely,the transitional flows over the flat plate boundary layer with zero pressure gradient,NACA0012,and Aerospatiale-A airfoils,were simulated.The simulation was performed by combining the optimized results from the proposed model with the equations of the well-known κ-ω shear stress transfer(SST)turbulence model.The numerical results show that the dual-eddy EMMS-based turbulence model improves the prediction in the laminar-turbulent transition process.This demonstrates the soundness of using the multiscale-structure concept in turbulent flows to establish the turbulence transition model by considering the principle of compromise-in-competition between viscosity and inertia.展开更多
基金supported by the National Key R&D Program of China(Grant No.2022YFB3302900)the National Natural Science Foundation of China(Grant No.52475261).
文摘Multiscale structures require excellent multiphysical properties to withstand the loads in various complex engineering fields.In this study,a concurrent isogeometric topology optimization method is proposed to design multiscale structures with high thermal conductivity and low mechanical compliance.First,the mathematical description model of multi-objective topology optimization for multiscale structures is constructed,and a single-objective concurrent isogeometric topology optimization formulation for mechanical and thermal compliance is proposed.Then,by combining the isogeometric analysis method,the material interpolation model and decoupled sensitivity analysis scheme of the objective function are established on macro and micro scales.The solid isotropic material with penalization method is employed to update iteratively the macro and microstructure topologies simultaneously.Finally,the feasibility and advantages of the proposed approach are illustrated by several 2D and 3D numerical examples with different volume fractions,while the effects of volume fraction and different boundary conditions on the final configuration and multi-objective performance of the multiscale structure are explored.Results show that the isogeometric concurrent design of multiscale structures through multi-objective optimization can produce better multi-objective performance compared with a single-scale one.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12275179,11875042,and 12150410309)the Natural Science Foundation of Shanghai(Grant No.21ZR1443900).
文摘The suprachiasmatic nucleus in the hypothalamus is the master circadian clock in mammals,coordinating physiological processes with the 24-hour day–night cycle.Comprising various cell types,the suprachiasmatic nucleus(SCN)integrates environmental signals to maintain complex and robust circadian rhythms.Understanding the complexity and synchrony within SCN neurons is essential for effective circadian clock function.Synchrony involves coordinated neuronal firing for robust rhythms,while complexity reflects diverse activity patterns and interactions,indicating adaptability.Interestingly,the SCN retains circadian rhythms in vitro,demonstrating intrinsic rhythmicity.This study introduces the multiscale structural complexity method to analyze changes in SCN neuronal activity and complexity at macro and micro levels,based on Bagrov et al.’s approach.By examining structural complexity and local complexities across scales,we aim to understand how tetrodotoxin,a neurotoxin that inhibits action potentials,affects SCN neurons.Our method captures critical scales in neuronal interactions that traditional methods may overlook.Validation with the Goodwin model confirms the reliability of our observations.By integrating experimental data with theoretical models,this study provides new insights into the effects of tetrodotoxin(TTX)on neuronal complexities,contributing to the understanding of circadian rhythms.
基金supported by the National Natural Science Foundation of China(No.52275380).
文摘Multi-scale lamellar structure significantly improves toughness of Ti_(2)AlNb based alloys,which are inher-ently brittle intermetallics,without compromising their strength.This structure was achieved through-B2-transus-forging(TBTF)combined with O+B2 two-phase region heat treatments.Various types of multi-scale lamellar structures were obtained by controlling the cooling rate after TBTF.These variations were mainly attributed to differences in the distribution,content,and size of the thick lamellar O phase and the size and crystallographic orientation of B2 grain.By analyzing the microstructural characteristics and crystallographic orientation near the crack propagation path,it was found that the crack propaga-tion resistance of thick lamellae,sub grain and grain boundaries(GBs)O phase increased sequentially,accompanied by more tortuous crack propagation path.Moreover,B2 grains with high misorientation significantly deflected the crack propagation by cleavage ridges between adjoining cleavage planes.Addi-tionally,the development of numerous secondary cleavage ridges,resulting from the transition through varying secondary cleavage planes in distinct sub B2 grains,further hindered the quick propagation of cracks.It was clarified that the cleavage planes were dominantly belonging to{110}.These findings pro-vided valuable guidance for the design of damage tolerance strategies for Ti_(2)AlNb-based intermetallics.
基金supported in part by the National Natural Science Foundation of China under Grant 62171203in part by the Jiangsu Province“333 Project”High-Level Talent Cultivation Subsidized Project+2 种基金in part by the SuzhouKey Supporting Subjects for Health Informatics under Grant SZFCXK202147in part by the Changshu Science and Technology Program under Grants CS202015 and CS202246in part by Changshu Key Laboratory of Medical Artificial Intelligence and Big Data under Grants CYZ202301 and CS202314.
文摘In this paper,we introduce a novel Multi-scale and Auto-tuned Semi-supervised Deep Subspace Clustering(MAS-DSC)algorithm,aimed at addressing the challenges of deep subspace clustering in high-dimensional real-world data,particularly in the field of medical imaging.Traditional deep subspace clustering algorithms,which are mostly unsupervised,are limited in their ability to effectively utilize the inherent prior knowledge in medical images.Our MAS-DSC algorithm incorporates a semi-supervised learning framework that uses a small amount of labeled data to guide the clustering process,thereby enhancing the discriminative power of the feature representations.Additionally,the multi-scale feature extraction mechanism is designed to adapt to the complexity of medical imaging data,resulting in more accurate clustering performance.To address the difficulty of hyperparameter selection in deep subspace clustering,this paper employs a Bayesian optimization algorithm for adaptive tuning of hyperparameters related to subspace clustering,prior knowledge constraints,and model loss weights.Extensive experiments on standard clustering datasets,including ORL,Coil20,and Coil100,validate the effectiveness of the MAS-DSC algorithm.The results show that with its multi-scale network structure and Bayesian hyperparameter optimization,MAS-DSC achieves excellent clustering results on these datasets.Furthermore,tests on a brain tumor dataset demonstrate the robustness of the algorithm and its ability to leverage prior knowledge for efficient feature extraction and enhanced clustering performance within a semi-supervised learning framework.
基金support from the National Natural Science Foundation of China(No.21878218)the Tianjin Research Innovation Project for Postgraduate Students(No.2023KJ262)+2 种基金the State Grid Corporation of China’s Research Program(No.5419-202019385A)the Fundamental Research Funds for the Central Universities(No.92320006)the Tianjin Key Science and Technology Program(No.18ZXSZSF00030)。
文摘Exploiting advanced nanocomposites isochronally integrating outstanding thermal conductivity(TC)and electromagnetic interference shielding effectiveness(EMI SE)can boost the cutting-edge application of phase change materials.Here,we report a tiramisu-like composite(GMP),where the typical“crust-and-cheese”hierarchical structure is replicated by an innovative two-step bidirectional freezing assembly(BFA)and compressive densification.Hierarchical-aligned graphene array(G-GA)with ultralow thermal resistance is fabricated through 1st BFA and graphitization.During the 2nd BFA,the MXene-CNF crosslinking network with hydrogen-bond actions is used for encapsulating polyethylene glycol(PEG)onto the microlayers of the G-GA skeleton.Remarkably,the microlaminated GMP4 achieves a recorded TC of 34.05 W m^(-1) K^(-1),unprecedented EMI SE of 87.4 dB,and preferable enthalpy density of 179.4 J cm^(-3),along with leakage-free function,and eminent thermal durability.Furthermore,the GMP-loaded equipment is demonstrated for efficient microelectronics cooling and sustainable solar energy utilization.This work opens new avenues for multiscale designing multifunctional macro-composites,broadening the application prospects in advanced electronics and solar energy utilization systems.
基金Taishan Scholar Project of Shandong Province(No.tsqn202306226)Natural Science Foundation of Shandong Prov-ince(No.ZR2023ME155)+1 种基金The project of“20 Items of University”of Jinan(No.202228046)Luzhou Municipal Science and Technol-ogy Plan Project(Nos.2024JYJ016 and 2024JYJ018).
文摘Alkaline electrolytic hydrogen production has emerged as one of the most practical methods for industrial-scale hydrogen production.However,the initial hydrolysis dissociation in alkaline media impedes the hydrogen evolution reaction(HER)kinetics of commercial catalysts.To overcome this limitation,this study focuses on the development of a highly efficient electrocatalyst for alkaline HER.Ni-based intermetallic compounds exhibit remarkable catalytic activity for HER,with the NiMo alloy being among the most active catalysts in alkaline environments.Here,we designed and fabricated self-supported multiscale porous NiZn/NiMo intermetallic compounds on a metal foam substrate using a versatile dealloying method.The resulting electrode exhibits excellent HER activity,achieving an overpotential of just 204 mV at 1000 mA/cm^(2),and dem-onstrates robust long-term catalytic stability,maintaining performance at 100 mA/cm^(2) for 400 h in an alkaline electrolyte.Thesefindings underscore the potential of nanosized intermetallic compounds fabricated via a dealloying approach to deliver exceptional catalytic performance for alkaline water electrolysis.
基金National Natural Science Foundation of China(Grant No.42002133,42072150)Science Foundation of China University of Petroleum,Beijing(No.2462021YXZZ003)the Strategic Cooperation Technology Projects of CNPC and CUPB(ZLZX2020-01-06)for the financial supports and permissions to publish this paper
文摘Fine-grained sedimentary rocks have become a research focus as important reservoirs and source rocks for tight and shale oil and gas.Laminae development determines the accumulation and production of tight and shale oil and gas in fine-grained rocks.However,due to the resolution limit of conventional logs,it is challenging to recognize the features of centimeter-scale laminae.To close this gap,complementary studies,including core observation,thin section,X-ray diffraction(XRD),conventional log analysis,and slabs of image logs,were conducted to unravel the centimeter-scale laminae.The laminae recognition models were built using well logs.The fine-grained rocks can be divided into laminated rocks(lamina thickness of<0.01 m),layered rocks(0.01-0.1 m),and massive rocks(no layer or layer spacing of>0.1 m)according to the laminae scale from core observations.According to the mineral superposition assemblages from thin-section observations,the laminated rocks can be further divided into binary,ternary,and multiple structures.The typical mineral components,slabs,and T2spectrum distributions of various lamina types are unraveled.The core can identify the centimeter-millimeter-scale laminae,and the thin section can identify the millimeter-micrometer-scale laminae.Furthermore,they can detect mineral types and their superposition sequence.Conventional logs can identify the meter-scale layers,whereas image logs and related slabs can identify the laminae variations at millimeter-centimeter scales.Therefore,the slab of image logs combined with thin sections can identify laminae assemblage characteristics,including the thickness and vertical assemblage.The identification and classification of lamina structure of various scales on a single well can be predicted using conventional logs,image logs,and slabs combined with thin sections.The layered rocks have better reservoir quality and oil-bearing potential than the massive and laminated rocks.The laminated rocks’binary lamina is better than the ternary and multiple layers due to the high content of felsic minerals.The abovementioned results build the prediction model for multiscale laminae structure using well logs,helping sweet spots prediction in the Permian Lucaogou Formation in the Jimusar Sag and fine-grained sedimentary rocks worldwide.
基金supported by the National Natural Science Foundation of China(52164015)the Technology Funding Projects of Guizhou Province([2022]231).
文摘The rich accumulation of methane(CH_(4))in tectonic coal layers poses a significant obstacle to the safe and efficient extraction of coal seams and coalbed methane.Tectonic coal samples from three geologically complex regions were selected,and the main results obtained by using a variety of research tools,such as physical tests,theoretical analyses,and numerical simulations,are as follows:22.4–62.5 nm is the joint segment of pore volume,and 26.7–100.7 nm is the joint segment of pore specific surface area.In the dynamic gas production process of tectonic coal pore structure,the adsorption method of methane molecules is“solid–liquid adsorption is the mainstay,and solid–gas adsorption coexists”.Methane stored in micropores with a pore size smaller than the jointed range is defined as solid-state pores.Pores within the jointed range,which transition from micropore filling to surface adsorption,are defined as gaseous pores.Pores outside the jointed range,where solid–liquid adsorption occurs,are defined as liquid pores.The evolution of pore structure affects the methane adsorption mode,which provides basic theoretical guidance for the development of coal seam resources.
基金supported by the National Natural Science Foundations of China(Nos.12172186 and 11772166).
文摘The objective of dynamical system learning tasks is to forecast the future behavior of a system by leveraging observed data.However,such systems can sometimes exhibit rigidity due to significant variations in component parameters or the presence of slow and fast variables,leading to challenges in learning.To overcome this limitation,we propose a multiscale differential-algebraic neural network(MDANN)method that utilizes Lagrangian mechanics and incorporates multiscale information for dynamical system learning.The MDANN method consists of two main components:the Lagrangian mechanics module and the multiscale module.The Lagrangian mechanics module embeds the system in Cartesian coordinates,adopts a differential-algebraic equation format,and uses Lagrange multipliers to impose constraints explicitly,simplifying the learning problem.The multiscale module converts high-frequency components into low-frequency components using radial scaling to learn subprocesses with large differences in velocity.Experimental results demonstrate that the proposed MDANN method effectively improves the learning of dynamical systems under rigid conditions.
基金This work was supported by NSF MRSEC DMR-1119826 and ONR YIP award N000141210657。
文摘Bulk metallic glasses(BMGs)have been developed as a means to achieve durable multiscale,nanotextured surfaces with desirable properties dictated by topography for a multitude of applications.One barrier to this achievement is the lack of a bridging technique between macroscale thermoplastic forming and nanoimprint lithography,which arises from the difficulty and cost of generating controlled nanostructures on complex geometries using conventional top-down approaches.This difficulty is compounded by the necessary destruction of any resulting reentrant structures during rigid demolding.We have developed a generalized method to overcome this limitation by sacrificial template imprinting using zinc oxide(ZnO)nanostructures.It is established that such structures can be grown inexpensively and quickly with tunable morphologies on a wide variety of substrates out of solution,which we exploit to generate the nanoscale portion of the multiscale pattern through this bottom-up approach.In this way,we achieve metallic structures that simultaneously demonstrate features from the macroscale down to the nanoscale,requiring only the top-down fabrication of macro/microstructured molds.Upon detachment of the formed part from the multiscale molds,the ZnO remains embedded in the surface and can be removed by etching in mild conditions to both regenerate the mold and render the surface of the BMGs nanoporous.The ability to pattern metallic surfaces in a single step on length scales from centimeters down to nanometers is a critical step toward fabricating devices with complex shapes that rely on multiscale topography for their intended functions,such as biomedical and electrochemical applications.
基金supported by the Shanghai Pujiang Program(No.2022PJD033)the Oceanic Interdisciplinary Program of Shanghai Jiao Tong University(No.SL2022MS013)the Key R&D Program of Zhejiang(No.2024SSYS0085).
文摘The development of aeroengine with a high thrust-weight ratio poses great challenges for current top-coating thermal barrier coatings (TBCs) and environmental barrier coatings (EBCs) in service. Medium/high-entropy ceramics are highly promising candidate material for advanced TBCs/EBCs owing to their low thermal conductivity, high melting point, high-temperature stability, and calcium–magnesium–alumino–silicate (CMAS) resistance. Most feedstock powder used for medium/high-entropy TBCs/EBCs is prepared via traditional spray drying, which cannot fully exploit the advantages of multicomponent ceramics. The density, sphericity, inner structure, and flowability of feedstock powder affect their melting state during the thermal spraying process, which strongly affects the microstructure and properties of the deposited coatings. Therefore, the deposited coatings exhibit phase segregation, amorphous phases, and microstructure defects owing to unpredictable variations in feedstock powder with random morphologies and structures. Here, the structure and properties of feedstock powder prepared by state-of-the-art granulation technologies and their influences on the deposited coatings were systematically investigated, which can provide guidance for configuration optimization of feedstock powder and the manufacturing accuracy of the deposited coating. This review aims to bridge the gap between cutting-edge ceramics and advanced engineering technologies, thus providing concrete background knowledge and crucial guidelines for designing and developing TBCs/EBCs.
基金supported by the Joint Funds of the National Natural Science Foundation of China(No.52021001)the Open Foundation of National Engineering Research Center of Electromagnetic Radiation Control Materials(No.KPKFJJ2024004-1)+3 种基金Important Project of the National Natural Science Foundation of China(No.62090012)Technological Achievements Transformation Projects of Central Universities and Institutes in Sichuan(No.2022ZHCG0114)Major Science and Technology Projects in Sichuan Province(No.2023ZDZX0016)the National Natural Science Foundation of China(No.52372103).
文摘Carbonyl iron absorbers(CI)face significant challenges in practical applications,such as corrosion,interface bonding failure,detachment,and high maintenance costs.Herein,we have developed intelligent self-healing technology based on proactive/passive mechanisms via in situ synthesis of self-healing factors(polydopamine/benzotriazole(PDA/BTA))and physical barrier layers(SiO_(2)/1,1,1,3,3,3-hexamethyl disilazane,SiO_(2)/HMDS)to enhance corrosion resistance,while also being compatible with efficient microwave absorption characteristics.The unique multiscale structure gives full play to the utilization of the roles of each functional layer,including the intelligent self-healing features of PDA/BTA,physical shielding and spatial confinement characteristics of SiO_(2)/HMDS,and magnetic-dielectric synergistic mechanism resulted from the good impedance matching characteristics,the conduction loss,the interfacial polarization loss and natural resonance.The asfabricated composites achieved an exceptional minimum reflection loss value of-55.4 dB at 10.7 GHz and the effective absorption band of 7.6 GHz.Moreover,it still exhibits obvious self-healing and corrosion resistance characteristics after 360 h corrosion treatment,ascribed to the self-healing mechanism of PDA/BTA and the blocking intervention effect of SiO_(2)/HMDS.This work is considered to pave the way for the synthesis of high-performance magnetic absorbers,especially in enhancing their intelligent self-healing ability in corrosive environments.
基金support from the National Natural Science Foundation of China(51933010,52433009)the Fundamental Research Funds for the Central Universities(GK202309019).
文摘Stretchable conjugated polymer films are pivotal in flexible and wearable electronics.Despite significant advancements in film stretchability through molecular engineering and multicomponent blending,these conjugated polymer films often exhibit limited elastic ranges and reduced carrier mobi-lities under large strain or after cyclic stretching.These limitations hinder their application in wearable electronics.Therefore,it is imperative to reveal the mechanical fatigue mechanisms and incorporate multiple strain energy dissipation strategies to enhance elastic deformation and electrical perform-ance of stretched conjugated polymer films.In this review,we begin by introducing the typical mechanical behaviors of conjugated polymer films.Subsequently,we discuss the multiscale structural evolution under various stretching conditions based on both in-situ and ex-situ characterizations.This analysis is further related to the diverse strain energy dissipation mechanisms.We next establish the correlation between strain-induced microstructure and the electrical performance of stretched conjugated polymer films.After that,we propose to develop highly elastic conjugated polymer films by constructing stable crosslinks and promoting polymer dynamics in low-crystalline polymer films.Finally,we highlight the future opportunities for high-performance and mechanically stable devices based on stretchable conjugated polymer films.
文摘The biased random walk on supercritical Galton–Watson trees is known to exhibit a multiscale phenomenon in the slow regime:the maximal displacement of the walk in the first n steps is of order(log n)3,whereas the typical displacement of the walk at the n-th step is of order(log n)2.Our main result reveals another multiscale property of biased walks:the maximal potential energy of the biased walks is of order(log n)2 in contrast with its typical size,which is of order log n.The proof relies on analyzing the intricate multiscale structure of the potential energy.
基金the financial support from the National Key R&D Program of China(No.2017YFA0204800)the National Natural Science Foundation of China(No.22002100)the Collaborative Innovation Center of Suzhou Nano Science and Technology,and the 111 Project and Joint International Research Laboratory of Carbon-Based Functional Materials and Devices.
文摘Carbon nitride(C_(3)N_(4))holds great promise for photocatalytic H_(2)O_(2)production from oxygen reduction.In spite of great research efforts,they still suffer from low catalytic efficiency primarily limited by the fast recombination of photogenerated charge carriers.In this work,we report the multiscale structural engineering of C_(3)N_(4)to significantly improve its optoelectronic properties and consequently photocatalytic performance.The product consists of porous spheres with high surface areas,abundant nitrogen defects,and alkali metal doping.Under visible light irradiation,our catalyst shows a remarkable H_(2)O_(2)production rate of 3,080μmol·g^(−1)·h^(−1),which is more than 10 times higher than that of bulk C_(3)N_(4)and exceeds those of most other C_(3)N_(4)-based photocatalysts.Moreover,the catalyst exhibits great stability,and can continuously work for 15 h without obvious activity decay under visible light irradiation,eventually giving rise to a high H_(2)O_(2)concentration of ca.45 mM.
基金supported by the National Natural Science Foundation of China(Nos.51732011,U1932213,22105194,and 92163130)the National Key Research and Development Program of China(Nos.2021YFA0715700 and 2018YFE0202201)+3 种基金the University Synergy Innovation Program of Anhui Province(No.GXXT-2019-028)Science and Technology Major Project of Anhui Province(No.201903a05020003)the Fundamental Research Funds for the Central Universities(No.WK2090050043)Anhui Provincial Key R&D Programs(No.202104a05020013).
文摘Different forms of construction materials(e.g.,paints,foams,and boards)dramatically improve the quality of life.With the increasing environmental requirements for buildings,it is necessary to develop a comprehensive sustainable construction material that is flexible in application and exhibits excellent performance,such as fireproofing and thermal insulation.Herein,an adjustable multiform material strategy by water regulation is proposed to meet the needs of comprehensive applications and reduce environmental costs.Multiform gels are constructed based on multiscale cellulose fibers and hollow glass microspheres,with fireproofing and thermal insulation.Unlike traditional materials,this multiscale cellulose-based gel can change forms from dispersion to paste to dough by adjusting its water content,which can realize various construction forms,including paints,foams,and low-density boards according to different scenarios and corresponding needs.
基金financially supported by the National Natural Science Foundation of China(Nos.52171224 and 92261119)J.M.W.acknowledges support from Zhejiang Province Postdoctoral Science Foundation(No.ZJ2022003)China Postdoctoral Science Foundation(No.2023M733020).
文摘The sluggish reaction kinetics of alkaline hydrogen oxidation reaction(HOR)is one of the key challenges for anion exchange membrane fuel cells(AEMFCs).To achieve robust alkaline HOR with minimized cost,we developed a single atom-cluster multiscale structure with isolated Pt single atoms anchored on Ru nanoclusters supported on nitrogen-doped carbon nanosheets(Pt1-Ru/NC).The well-defined structure not only provides multiple sites with varied affinity with the intermediates but also enables simultaneous modulation of different sites via interfacial interaction.In addition to weakening Ru–H bond strength,the isolated Pt sites are heavily involved in hydrogen adsorption and synergistically accelerate the Volmer step with the help of Ru sites.Furthermore,this catalyst configuration inhibits the excessive occupancy of oxygen-containing species on Ru sites and facilitates the HOR at elevated potentials.The Pt1-Ru/NC catalyst exhibits superior alkaline HOR performance with extremely high activity and excellent CO-tolerance.An AEMFC with a 0.1 mg·cmPGM^(−2)loading of Pt1-Ru/NC anode catalyst achieves a peak powder density of 1172 mW·cm^(−2),which is 2.17 and 1.55 times higher than that of Pt/C and PtRu/C,respectively.This work provides a new catalyst concept to address the sluggish kinetics of electrocatalytic reactions containing multiple intermediates and elemental steps.
基金supported by the National Key R&D Program of China(Nos.2021YFA1501102,2023YFA1506602)the National Natural Science Foundation of China(Nos.21932002,22276023 and 21902018)+3 种基金the National High-Level Talents Special Support Program,the Outstanding Young Scientific Talent of Dalian(2023RY011)the Fundamental Research Funds for the Central Universities(DUT20ZD205,DUT22ZD212,DUT21RC(3)095,and DUT22LAB602)Liaoning Binhai Laboratory Project(LBLF-202306)the Star Ocean Outstanding Young Talents Program.
文摘A novel electrocatalyst,Ni-Co/β-Mo_(2)C@C,was rationally designed to enhance the efficiency of the hydrogen evolution reaction(HER)in this work.Assembled with two-dimensional Ni-Co nanosheets onto Mo_(2)C nanorods coated with a thin carbon shell,the catalyst demonstrates remarkable performance,including low overpotential(η_(10)=57 mV)and reduced Tafel slope(63 mV·dec^(–1))in 0.5 mol·L^(–1)H_(2)SO_(4) electrolyte.This innovative design strategy provides abundant active sites and efficient electron/ion transport pathways,effectively shortening reactant diffusion distances and enhancing electrocatalytic activity.Additionally,the carbon shell coating protects the catalyst from etching and agglomeration,ensuring its durability.This work presents a promising approach for engineering highly efficient metal carbide-based HER catalysts through tailored composition and nanostructure design.
基金financially supported by the Key Research and Development Program of Hubei Province(2020BCA079)the National Natural Science Foundation of China(52173106)。
基金financially supported by the National Key R&D Program of China(No.2018YFB1500902)National Numerical Wind Tunnel Project of China(No.NNW2020ZT1-A20)+1 种基金National Natural Science Foundation of China(Nos.51776212,91434113)Chinese Academy of Sciences(No.QYZDB-SSW-SYS029).
文摘Turbulence is a century-old physics problem,and the prediction of laminar-turbulent transition remains a major challenge in computational fluid dynamics(CFD).This paper proposes a new conceptual multiscale-structure flow system consisting of a nonturbulent part and two types of turbulent eddies with different properties.The stability criterion for turbulent transition flows,based on the principle of compromise-in-competition between viscosity and inertia,is used to obtain model closure.The multiscale-structure concept and stability criterion are the characteristics of the dual-eddy energy-minimization multiscale(EMMS)-based turbulence model.The solved heterogeneous structure parameters and energy dissipation rate are analyzed,which reveal the laminar-turbulent transition process.To validate the dual-eddy EMMS-based turbulence model,three benchmark problems,namely,the transitional flows over the flat plate boundary layer with zero pressure gradient,NACA0012,and Aerospatiale-A airfoils,were simulated.The simulation was performed by combining the optimized results from the proposed model with the equations of the well-known κ-ω shear stress transfer(SST)turbulence model.The numerical results show that the dual-eddy EMMS-based turbulence model improves the prediction in the laminar-turbulent transition process.This demonstrates the soundness of using the multiscale-structure concept in turbulent flows to establish the turbulence transition model by considering the principle of compromise-in-competition between viscosity and inertia.
