It is known that structural optimization may lead to designs of structures having low stability and sometimes even kinematically unstable designs. This paper presents a robust design method for improving the stability...It is known that structural optimization may lead to designs of structures having low stability and sometimes even kinematically unstable designs. This paper presents a robust design method for improving the stability of opti mized structures. A new approach is proposed, in which cer tain perturbation loads are introduced and the corresponding compliance is added to the objective function as a penaliza tion. The stability of the optimized structures can thus be improved substantially by considering structural responses to the original and the introduced loads. Numerical exam ples show the simplicity and effectiveness of the proposed method.展开更多
The vacuum vessel of the HT-7U superconducting tokamak will be a fully-welded structure with a double-wall. The space between the double-wall will be filled with borated water for neutron shielding. Non-circular cross...The vacuum vessel of the HT-7U superconducting tokamak will be a fully-welded structure with a double-wall. The space between the double-wall will be filled with borated water for neutron shielding. Non-circular cross-section is designed for plasma elongating. Horizontal and vertical ports are designed for diagnosing, vacuum pumping, plasma heating and plasma current driving, etc. The vacuum vessel consists of 16 segments. It will be baked out at 250℃ to obtain a clean wall. When the machine is in operation, both the hot wall (the wall temperature is around 100℃) and the cold wall (wall temperature is in normal equilibrium) are considered. The stress caused by thermal deformation and the electromagnetic (EM) loads caused by 1.5 MA plasma disruption in 3.5 T magnetic field have to be taken into account in the design of the HT-7U vacuum vessel Finite element method was employed for structure analysis of the vacuum vessel.展开更多
Idiopathic pulmonary fibrosis(IPF)is a progressive lung disease and its incidence rate is rapidly rising.However,effective therapies for the treatment of IPF are still lacking.Phosphodiesterase 4(PDE4)inhibitors were ...Idiopathic pulmonary fibrosis(IPF)is a progressive lung disease and its incidence rate is rapidly rising.However,effective therapies for the treatment of IPF are still lacking.Phosphodiesterase 4(PDE4)inhibitors were reported to be potential anti-fibrotic agents.Herein,structure-based hit-to-lead optimization of natural isoaurostatin(8.98μmol/L)resulted in several potent inhibitors of PDE4 with half maximal inhibitory concentration(IC_(50))values ranging from 35 nmol/L to 126 nmol/L.Co-crystal structures revealed that isoaurostatin compounds exhibited different binding patterns from the classic PDE4 inhibitor rolipram and the analogues would favor to be Z configurations other than the corresponding E isomers.Finally,lead 2–9 showed remarkable in vitro/in vivo anti-fibrotic effects indicating its potential as a novel anti-IPF agent.展开更多
Magnesium alloy,as a new material for vascular stents,possesses excellent mechanical properties,biocompatibility,and biodegradability.However,the mechanical properties of magnesium alloy stents exhibit relatively infe...Magnesium alloy,as a new material for vascular stents,possesses excellent mechanical properties,biocompatibility,and biodegradability.However,the mechanical properties of magnesium alloy stents exhibit relatively inferior performance compared to traditional metal stents with identical structural characteristics.Therefore,improving their mechanical properties is a key issue in the development of biodegradable magnesium alloy stents.In this study,three new stent structures(i.e.,stent A,stent B,and stent C)were designed based on the typical structure of biodegradable stents.The changes made included altering the angle and arrangement of the support rings to create a support ring structure with alternating large and small angles,as well as modifying the position and shape of the link.Using finite element analysis,the compressive performance,expansion performance,bending flexibility performance,damage to blood vessels,and hemodynamic changes of the stent were used as evaluation indexes.The results of these comprehensive evaluations were utilized as the primary criteria for selecting the most suitable stent design.The results demonstrated that compared to the traditional stent,stents A,B,and C exhibited improvements in radial stiffness of 16.9%,15.1%,and 37.8%,respectively;reductions in bending stiffness of 27.3%,7.6%,and 38.1%,respectively;decreases in dog-boning rate of 5.1%,93.9%,and 31.3%,respectively;as well as declines in the low wall shear stress region by 50.1%,43.8%,and 36.2%,respectively.In comparison to traditional stents,a reduction in radial recoiling was observed for stents A and C,with decreases of 9.3% and 7.4%,respectively.Although there was a slight increase in vessel damage for stents A,B,and C compared to traditional stents,this difference was not significant to have an impact.The changes in intravascular blood flow rate were essentially the same after implantation of the four stents.A comparison of the four stents revealed that stents A and C exhibited superior overall mechanical properties and they have greater potential for clinical application.This study provides a reference for designing clinical stent structures.展开更多
In the new phase of sustainable development,agriculture is seeking sustainable management of the water-land-energy-economy-environment-food nexus.At present,there are few studies on optimizing crop planting structure ...In the new phase of sustainable development,agriculture is seeking sustainable management of the water-land-energy-economy-environment-food nexus.At present,there are few studies on optimizing crop planting structure and analyzing its spatial layout with consideration of natural and socio-economic factors.Herein,we proposed a framework for addressing this issue.In this framework,the NSGA-II algorithm was used to construct the multi-objective optimization model of crop planting structures with consideration of water and energy consumption,greenhouse gas(GHG)emissions,economic benefits,as well as food,land,and water security constraints,while the model for planting spatial layout optimization was established with consideration of crop suitability using the MaxEnt model and the improved Hungarian algorithm.This framework was further applied in the Black Soil Region of Northeast China(BSRNC)for analyzing optimized crop planting structures and spatial layouts of three main crops(rice,maize,and soybean)under various scenarios.This study showed that the sown area of rice in the BSRNC decreased by up to 40.73%and 35.30%in the environmental priority scenario and economic-environmental balance scenario,respectively,whereas that of soybean increased by up to 112.44%and 63.31%,respectively.In the economic priority scenario,the sown area of rice increased by up to 93.98%.Expanding the sown area of soybean was effective in reducing GHG emissions.On the contrary,rice production led to greater environmental costs though it provided higher economic returns.Among the three crops,maize exhibited an advantage in balancing environmental and economic benefits.Hegang-Jixi area in the northeast of the BSRNC was identified as the key area with the most intense crop planting transfer among different scenarios.Overall,this framework provides a new methodology for optimizing crop planting structures and spatial layouts with con-sideration of the nexus of various factors.Moreover,the case study demonstrates the applicability and expansion potential of the framework in the fields of sustainable agricultural development and food security assurance.展开更多
The beam pumping unit(BPU)remains the most stable and reliable equipment for crude oil lifting.Despite its simple four-link mechanism,the structural design of the BPU presents a constrained single-objective optimizati...The beam pumping unit(BPU)remains the most stable and reliable equipment for crude oil lifting.Despite its simple four-link mechanism,the structural design of the BPU presents a constrained single-objective optimization problem.Currently,a comprehensive framework for the structural design and optimization of compound balanced BPUs is lacking.Therefore,this study proposes a novel structural design scheme for BPUs,aiming to meet the practical needs of designers and operators by sequentially optimizing both the dynamic characteristics and balance properties of the BPUs.A dynamic model of compound balanced BPU was established based on D'Alembert's principle.The constraints for structural dimensions were formulated based on the actual operational requirements and design experience with BPUs.To optimize the structure,three algorithms were employed:the particle swarm optimization(PSO)algorithm,the genetic algorithm(GA),and the gray wolf optimization(GWO)algorithm.Each newly generated individuals are regulated by constraints to ensure the rationality of the outcomes.Furthermore,the integration of three algorithms ensures the increased likelihood of attaining the global optimal solution.The polished rod acceleration of the optimized structure is significantly reduced,and the dynamic characteristics of the up and down strokes are essentially symmetrical.Additionally,these three algorithms are also applied to the balance optimization of BPUs based on the measured dynamometer card.The calculation results demonstrate that the GWO-based optimization method exhibits excellent robustness in terms of structural optimization by enhancing the operational smoothness of the BPU,as well as in balance optimization by achieving energy conservation.By applying the optimization scheme proposed in this paper,the CYJW7-3-23HF type of BPU was designed,achieving a maximum polished rod acceleration of±0.675 m/s^(2) when operating at a stroke of 6 min^(−1).When deployed in two wells,the root-mean-square(RMS)torque was minimized,reaching values of 7.539 kN·m and 12.921 kN·m,respectively.The proposed design method not only contributes to the personalized customization but also improves the design efficiency of compound balanced BPUs.展开更多
The optimization of civil engineering structures is critical for enhancing structural performance and material efficiency in engineering applications.Structural optimization approaches seek to determine the optimal de...The optimization of civil engineering structures is critical for enhancing structural performance and material efficiency in engineering applications.Structural optimization approaches seek to determine the optimal design,by considering material performance,cost,and structural safety.The design approaches aim to reduce the built environment’s energy use and carbon emissions.This comprehensive review examines optimization techniques,including size,shape,topology,and multi-objective approaches,by integrating these methodologies.The trends and advancements that contribute to developing more efficient,cost-effective,and reliable structural designs were identified.The review also discusses emerging technologies,such as machine learning applications with different optimization techniques.Optimization of truss,frame,tensegrity,reinforced concrete,origami,pantographic,and adaptive structures are covered and discussed.Optimization techniques are explained,including metaheuristics,genetic algorithm,particle swarm,ant-colony,harmony search algorithm,and their applications with mentioned structure types.Linear and non-linear structures,including geometric and material nonlinearity,are distinguished.The role of optimization in active structures,structural design,seismic design,form-finding,and structural control is taken into account,and the most recent techniques and advancements are mentioned.展开更多
Flow velocity uniformity of the microchannel plate is a major factor affecting the performance of microchannel devices.In order to improve the velocity distribution uniformity of the microchannel plate,we designed two...Flow velocity uniformity of the microchannel plate is a major factor affecting the performance of microchannel devices.In order to improve the velocity distribution uniformity of the microchannel plate,we designed two new microchannel structures:V-type and A-type.The effects of various structural parameters of the manifolds on the velocity distribution are reported.The V-type and A-type microchannel plates had a more uniform velocity distribution compared to the Z-type microchannel plate.The final result showed that it is beneficial for the V-type microchannel plate to obtain a more uniform velocity distribution when the manifold structure parameters are X_(in)=-1,X_(out)=0,Y_(in)=10,Y_(out)=6,Hin=4,H_(out)=1,and R=0.5.展开更多
Purpose–This paper aims to provide a comprehensive analysis of the strategic adjustments in China’s transportation structure,with a particular focus on the pivotal role of railway freight and its integration into th...Purpose–This paper aims to provide a comprehensive analysis of the strategic adjustments in China’s transportation structure,with a particular focus on the pivotal role of railway freight and its integration into the modern logistics system.It seeks to address the need for a more nuanced understanding of the“road to rail”policy,emphasizing the importance of intermodal collaboration and service of fragmented market demands.Design/methodology/approach–The study employs a transport economics perspective to evaluate the achievements and shortcomings of China’s transportation structure optimization.It bases its assessment of the current state of railway freight logistics,multi-modal transportation and the broader implications for the transportation service market on data analysis.The methodology includes a review of existing policies,an examination of industry practices and a comparative analysis with global trends in railway logistics.Findings–The research underscores the importance of focusing on the development of non-bulk materials,noting the insufficiency in the development of China’s rail multi-modal transportation and highlighting the instructive value of successful cases in open-top container road-rail intermodal transportation.The study posits that the railway sector must enhance cooperation with other market entities,aligning with the lead enterprises in the logistics chain that are characterized by speed,high value and strong coordination capabilities,in order to better serve the transportation market.This approach moves away from a reliance on the railway’s own capabilities alone.Originality/value–This paper offers original insights into the transformation of railway freight in China,contributing to the body of knowledge on transportation economics and logistics.It provides valuable recommendations for policymakers and industry practitioners,emphasizing the strategic importance of railway logistics in the context of China’s economic development and intense competition in the supply chain.The value of the article lies in its comprehensive understanding of the complexities involved in the adjustment of transportation structures,providing direction for the market-oriented reform of China’s railway freight sector.展开更多
In this paper,the front axle of a certain model is taken as the research object,and the stress and deformation of the frontaxle under three typical working conditions are analyzed by finite element technology.Based on...In this paper,the front axle of a certain model is taken as the research object,and the stress and deformation of the frontaxle under three typical working conditions are analyzed by finite element technology.Based on the simulation results,the 3D model of the front axle was optimized,and the finite element analysis of the optimized structure of the front axle under three typical working conditions was carried out to verify the correctness of the model.Finally,the fatigue tool module of ANSYS Workbench was used to analyze the fatigue life of the front axle under the optimized emergency conditions,and the feasibility of the model was verified.The analysis data shows that the design of the front axle components still has a lot of potential for lightweighting,and the weight of the front axle can be reduced by 6.73%through optimization,and the performance of the front axle can also meet the needs of use.The research conclusionhas a certain reference value for the lightweight design of automobile front axle.展开更多
Green finance,as an important policy to promote high-quality economic development,has become a focus of attention in the academic and policy circles for its promotion of industrial structure optimization.Based on the ...Green finance,as an important policy to promote high-quality economic development,has become a focus of attention in the academic and policy circles for its promotion of industrial structure optimization.Based on the data of six provinces in Central China from 2010 to 2023,this paper constructs a comprehensive index of green finance development by using entropy value method and empirically analyses the impact of green finance on industrial structure optimization.The results show that the level of green finance development has a significant contribution to the optimization of the industrial structure in the central region.Accordingly,this study provides suggestions for deepening green finance reform and accelerating industrial transformation and upgrading.展开更多
Under the background of this era,green finance and the upgrading and optimization of industrial structure have become a hot research topic.The article focuses on Jiangsu Province,carefully explores the impact of green...Under the background of this era,green finance and the upgrading and optimization of industrial structure have become a hot research topic.The article focuses on Jiangsu Province,carefully explores the impact of green financial development on the upgrading and optimization of industrial structure and the real effect,collates and summarizes the theories of green finance and industrial structure at home and abroad,and carefully analyzes the development of green finance in Jiangsu Province,such as the gradual expansion of green credit scale,the characteristics of industrial structure,the change of the proportion of three industries,the development situation of emerging industries and so on.By means of econometrics,an empirical model covering Green Financial Development Indicators and industrial structure optimization indicators is established to do multiple linear regression analysis and stability test.The empirical results show that the development of green finance in Jiangsu plays an obvious positive role in the optimization and upgrading of industrial structure.Green finance is environmental protection,new energy and other green industries are given important financial support,which drives their scale expansion and technological innovation,and makes the industrial structure develop towards a higher level and a more reasonable direction.From this point of view,corresponding proposals are put forward to improve the policy incentive system,add green financial products,and strengthen the construction of green financial market.The purpose is to give better play to the advantages of green finance,accelerate the optimization and upgrading of industrial structure in Jiangsu,and provide theoretical basis and practical guidance for achieving green economic transformation and sustainable development.展开更多
Build-up panels for the commercial aircraft fuselage subjected to the axial compression load are studied by both experimental and theoretical methods.An integral panel is designed with the same overall size and weight...Build-up panels for the commercial aircraft fuselage subjected to the axial compression load are studied by both experimental and theoretical methods.An integral panel is designed with the same overall size and weight as the build-up structure,and finite element models（FEMs）of these two panels are established.Experimental results of build-up panels agree well with the FEM results with the nonliearity and the large deformation,so FEMs are validated.FEM calculation results of these two panels indicate that the failure mode of the integral panel is different from that of the build-up panel,and the failure load increases by 18.4% up to post-buckling.Furthermore,the integral structure is optimized by using the multi-island genetic algorithm and the sequential quadratic programming.Compared with the initial design,the optimal mass is reduced by 8.7% and the strength is unchanged.展开更多
A new exist-null combined model is proposed for the structural topology optimization. The model is applied to the topology optimization of the truss with stress constraints. Satisfactory computational result can be ob...A new exist-null combined model is proposed for the structural topology optimization. The model is applied to the topology optimization of the truss with stress constraints. Satisfactory computational result can be obtained with more rapid and more stable convergence as compared with the cross-sectional optimization. This work also shows that the presence of independent and continuous topological variable motivates the research of structural topology optimization.展开更多
Land use structure optimization(LUSO) is an important issue for land use planning. In order for land use planning to have reasonable flexibility, uncertain optimization should be applied for LUSO. In this paper, the r...Land use structure optimization(LUSO) is an important issue for land use planning. In order for land use planning to have reasonable flexibility, uncertain optimization should be applied for LUSO. In this paper, the researcher first expounded the uncertainties of LUSO. Based on this, an interval programming model was developed, of which interval variables were to hold land use uncertainties. To solve the model, a heuristics based on Genetic Algorithm was designed according to Pareto Optimum principle with a confidence interval under given significance level to represent LUSO result. Proposed method was applied to a real case of Yangzhou, an eastern city in China. The following conclusions were reached. 1) Different forms of uncertainties ranged from certainty to indeterminacy lay in the five steps of LUSO, indicating necessary need of comprehensive approach to quantify them. 2) With regards to trade-offs of conflicted objectives and preferences to uncertainties, our proposed model displayed good ability of making planning decision process transparent, therefore providing an effective tool for flexible land use planning compiling. 3) Under uncertain conditions, land use planning effectiveness can be primarily enhanced by flexible management with reserved space to percept and hold uncertainties in advance.展开更多
Sintering characteristics of common fluxes and sintering blending ores, such as mineralization capacity, liquid generation capacity, consolidation strength, were examined to master the behavior and effect of fluxes in...Sintering characteristics of common fluxes and sintering blending ores, such as mineralization capacity, liquid generation capacity, consolidation strength, were examined to master the behavior and effect of fluxes in sintering. Based on fundamental studies, sinter pot tests were carried out to obtain the principles of optimizing the sinter flux structure. The results showed that strong mineralization capacity, liquid phase generation capacity, and consolidation strength were obtained as sintering blending ores combined with the calcareous flux, while rela-tively poor sintering characteristics were obtained as sintering blending ores combined with the magnesian flux. High reactive quicklime should be used as much as possible in the sintering mixture. It reached better sintering results while quicklime was used instead of limestone and its appropriate proportion in the sintering mixture was around 4wt%. On the premise of ensuring the MgO content, the dolomite amount should be decreased, and the substitution of quicklime for dolomite caused better sintering results. The granularity of serpentine should be re-fined with a proper size smaller than 2 mm. The application of the divided addition method brought the best sintering performance with 30wt% of quicklime and 70wt% of fuel.展开更多
An aeroelastic two-level optimization methodology for preliminary design of wing struc- tures is presented, in which the parameters for structural layout and sizes are taken as design vari- ables in the first-level op...An aeroelastic two-level optimization methodology for preliminary design of wing struc- tures is presented, in which the parameters for structural layout and sizes are taken as design vari- ables in the first-level optimization, and robust constraints in conjunction with conventional aeroelastic constraints are considered in the second-level optimization. A low-order panel method is used for aerodynamic analysis in the first-level optimization, and a high-order panel method is employed in the second-level optimization. It is concluded that the design of the abovementioned structural parameters of a wing can be improved using the present method with high efficiency. An improvement is seen in aeroelastic performance of the wing obtained with the present method when compared to the initial wing. Since these optimized structures are obtained after consideration of aerodynamic and structural uncertainties, they are well suited to encounter these uncertainties when they occur in reality.展开更多
Cavitating jet is a promising drilling rate improvement technology in both the marine natural gas hydrate (NGH) fluidization exploitation method and the integrated radial jet drilling and completion method. In present...Cavitating jet is a promising drilling rate improvement technology in both the marine natural gas hydrate (NGH) fluidization exploitation method and the integrated radial jet drilling and completion method. In present study, we aim to improve the efficiency of jet erosion and extracting NGH. With a computational fluid dynamics (CFD) method, the pressure, velocity and cavitation field characteristics of organ-pipe cavitating jet (OPCJ) are analysed. The divergent angle, throat length, and divergent length of OPCJ nozzle are preferred to obtain stronger jet cavitation erosion effect. Laboratory experiments of gas hydrate-bearing sediments (GHBS) erosion by OPCJ and conical jet (CJ) are conducted to compare and validate the jet erosion performance. The impinging models of OPCJ and CJ are constructed to study the impact characteristics. Results show that the preferred values of divergent angle, throat length, and divergent length are 15°, 1d, and 3d, respectively, in present simulation conditions. For GHBS, the OPCJ possesses the advantages of high efficiency and low energy consumption. Moreover, the OPCJ has higher penetration efficiency, while showing equivalent penetration ability compared to CJ. During the impinging process, the OPCJ can induce stronger impact pressure and turbulence effect, and also shows stronger chambering effect and bottom cleaning ability compared to CJ. This study presents the erosion performance of OPCJ and CJ on GHBS, and provides preliminary insights on the potential field applications in NGH exploitation.展开更多
A large number of mathematical models were developed for supporting agricultural production structure optimization decisions; however, few of them can address various uncertainties existing in many factors （e.g., eco...A large number of mathematical models were developed for supporting agricultural production structure optimization decisions; however, few of them can address various uncertainties existing in many factors （e.g., eco-social benefit maximization, food security, employment stability and ecosystem balance）. In this study, an interval-probabilistic agricultural production structure optimization model （IPAPSOM） is formulated for tackling uncertainty presented as discrete intervals and/or probability distribution. The developed model improves upon the existing probabilistic programming and inexact optimization approaches. The IPAPSOM considers not only food security policy constraints, but also involves rural households’income increase and eco-environmental conversation, which can effectively reflect various interrelations among different aspects in an agricultural production structure optimization system. Moreover, it can also help examine the reliability of satisfying （or risk of violating） system constraints under uncertainty. The model is applied to a real case of long-term agricultural production structure optimization in Dancheng County, which is located in Henan Province of Central China as one of the major grain producing areas. Interval solutions associated with different risk levels of constraint violation are obtained. The results are useful for generating a range of decision alternatives under various system benefit conditions, and thus helping decision makers to identify the desired agricultural production structure optimization strategy under uncertainty.展开更多
基金supported by State Key Laboratory of Structural Analysis for Industrial Equipment,Dalian University of Technology,China(GZ1305)the National Natural Science Foundation of China(11002058 and 11372004)
文摘It is known that structural optimization may lead to designs of structures having low stability and sometimes even kinematically unstable designs. This paper presents a robust design method for improving the stability of opti mized structures. A new approach is proposed, in which cer tain perturbation loads are introduced and the corresponding compliance is added to the objective function as a penaliza tion. The stability of the optimized structures can thus be improved substantially by considering structural responses to the original and the introduced loads. Numerical exam ples show the simplicity and effectiveness of the proposed method.
文摘The vacuum vessel of the HT-7U superconducting tokamak will be a fully-welded structure with a double-wall. The space between the double-wall will be filled with borated water for neutron shielding. Non-circular cross-section is designed for plasma elongating. Horizontal and vertical ports are designed for diagnosing, vacuum pumping, plasma heating and plasma current driving, etc. The vacuum vessel consists of 16 segments. It will be baked out at 250℃ to obtain a clean wall. When the machine is in operation, both the hot wall (the wall temperature is around 100℃) and the cold wall (wall temperature is in normal equilibrium) are considered. The stress caused by thermal deformation and the electromagnetic (EM) loads caused by 1.5 MA plasma disruption in 3.5 T magnetic field have to be taken into account in the design of the HT-7U vacuum vessel Finite element method was employed for structure analysis of the vacuum vessel.
基金supported by the Natural Science Foundation of China(Nos.22277019,82150204,22307031,22377023,22077143,and 82003594)Key Project of Guangdong Natural Science Foundation(No.2016A030311033)+2 种基金Fundamental Research Funds for Hainan University(Nos.KYQD(ZR)-21031,KYQD(ZR)-21108,KYQD(ZR)-23003,and XTCX2022JKA01)Guangdong Provincial Key Laboratory of Construction Foundation(No.2023B1212060022)Science Foundation of Hainan Province(Nos.KJRC2023B10,824YXQN420,and 324MS018)。
文摘Idiopathic pulmonary fibrosis(IPF)is a progressive lung disease and its incidence rate is rapidly rising.However,effective therapies for the treatment of IPF are still lacking.Phosphodiesterase 4(PDE4)inhibitors were reported to be potential anti-fibrotic agents.Herein,structure-based hit-to-lead optimization of natural isoaurostatin(8.98μmol/L)resulted in several potent inhibitors of PDE4 with half maximal inhibitory concentration(IC_(50))values ranging from 35 nmol/L to 126 nmol/L.Co-crystal structures revealed that isoaurostatin compounds exhibited different binding patterns from the classic PDE4 inhibitor rolipram and the analogues would favor to be Z configurations other than the corresponding E isomers.Finally,lead 2–9 showed remarkable in vitro/in vivo anti-fibrotic effects indicating its potential as a novel anti-IPF agent.
基金supported by the National Natural Science Foundation of China(Grant Nos.12272250 and 12372310)China Postdoctoral Science Foundation(Grant No.2020M680913)+1 种基金Shanxi Scholarship Council of China(Grant No.2022-081)Shanxi Postgraduate Innovation Project and Shanxi Huajin Orthopaedic Public Foundation.
文摘Magnesium alloy,as a new material for vascular stents,possesses excellent mechanical properties,biocompatibility,and biodegradability.However,the mechanical properties of magnesium alloy stents exhibit relatively inferior performance compared to traditional metal stents with identical structural characteristics.Therefore,improving their mechanical properties is a key issue in the development of biodegradable magnesium alloy stents.In this study,three new stent structures(i.e.,stent A,stent B,and stent C)were designed based on the typical structure of biodegradable stents.The changes made included altering the angle and arrangement of the support rings to create a support ring structure with alternating large and small angles,as well as modifying the position and shape of the link.Using finite element analysis,the compressive performance,expansion performance,bending flexibility performance,damage to blood vessels,and hemodynamic changes of the stent were used as evaluation indexes.The results of these comprehensive evaluations were utilized as the primary criteria for selecting the most suitable stent design.The results demonstrated that compared to the traditional stent,stents A,B,and C exhibited improvements in radial stiffness of 16.9%,15.1%,and 37.8%,respectively;reductions in bending stiffness of 27.3%,7.6%,and 38.1%,respectively;decreases in dog-boning rate of 5.1%,93.9%,and 31.3%,respectively;as well as declines in the low wall shear stress region by 50.1%,43.8%,and 36.2%,respectively.In comparison to traditional stents,a reduction in radial recoiling was observed for stents A and C,with decreases of 9.3% and 7.4%,respectively.Although there was a slight increase in vessel damage for stents A,B,and C compared to traditional stents,this difference was not significant to have an impact.The changes in intravascular blood flow rate were essentially the same after implantation of the four stents.A comparison of the four stents revealed that stents A and C exhibited superior overall mechanical properties and they have greater potential for clinical application.This study provides a reference for designing clinical stent structures.
基金funded by the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(Grant No.72221002)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA28060200)National Natural Science Foundation of Youth Project(Grant No.72303087).
文摘In the new phase of sustainable development,agriculture is seeking sustainable management of the water-land-energy-economy-environment-food nexus.At present,there are few studies on optimizing crop planting structure and analyzing its spatial layout with consideration of natural and socio-economic factors.Herein,we proposed a framework for addressing this issue.In this framework,the NSGA-II algorithm was used to construct the multi-objective optimization model of crop planting structures with consideration of water and energy consumption,greenhouse gas(GHG)emissions,economic benefits,as well as food,land,and water security constraints,while the model for planting spatial layout optimization was established with consideration of crop suitability using the MaxEnt model and the improved Hungarian algorithm.This framework was further applied in the Black Soil Region of Northeast China(BSRNC)for analyzing optimized crop planting structures and spatial layouts of three main crops(rice,maize,and soybean)under various scenarios.This study showed that the sown area of rice in the BSRNC decreased by up to 40.73%and 35.30%in the environmental priority scenario and economic-environmental balance scenario,respectively,whereas that of soybean increased by up to 112.44%and 63.31%,respectively.In the economic priority scenario,the sown area of rice increased by up to 93.98%.Expanding the sown area of soybean was effective in reducing GHG emissions.On the contrary,rice production led to greater environmental costs though it provided higher economic returns.Among the three crops,maize exhibited an advantage in balancing environmental and economic benefits.Hegang-Jixi area in the northeast of the BSRNC was identified as the key area with the most intense crop planting transfer among different scenarios.Overall,this framework provides a new methodology for optimizing crop planting structures and spatial layouts with con-sideration of the nexus of various factors.Moreover,the case study demonstrates the applicability and expansion potential of the framework in the fields of sustainable agricultural development and food security assurance.
基金supported by the Key Laboratory of Petroleum and Natural Gas Equipment,Ministry of Education(No.OGE202303-08)Engineering Technology Research Center for Industrial Internet of Things and Intelligent Sensing,Hubei Province(No.KXZ 202203).
文摘The beam pumping unit(BPU)remains the most stable and reliable equipment for crude oil lifting.Despite its simple four-link mechanism,the structural design of the BPU presents a constrained single-objective optimization problem.Currently,a comprehensive framework for the structural design and optimization of compound balanced BPUs is lacking.Therefore,this study proposes a novel structural design scheme for BPUs,aiming to meet the practical needs of designers and operators by sequentially optimizing both the dynamic characteristics and balance properties of the BPUs.A dynamic model of compound balanced BPU was established based on D'Alembert's principle.The constraints for structural dimensions were formulated based on the actual operational requirements and design experience with BPUs.To optimize the structure,three algorithms were employed:the particle swarm optimization(PSO)algorithm,the genetic algorithm(GA),and the gray wolf optimization(GWO)algorithm.Each newly generated individuals are regulated by constraints to ensure the rationality of the outcomes.Furthermore,the integration of three algorithms ensures the increased likelihood of attaining the global optimal solution.The polished rod acceleration of the optimized structure is significantly reduced,and the dynamic characteristics of the up and down strokes are essentially symmetrical.Additionally,these three algorithms are also applied to the balance optimization of BPUs based on the measured dynamometer card.The calculation results demonstrate that the GWO-based optimization method exhibits excellent robustness in terms of structural optimization by enhancing the operational smoothness of the BPU,as well as in balance optimization by achieving energy conservation.By applying the optimization scheme proposed in this paper,the CYJW7-3-23HF type of BPU was designed,achieving a maximum polished rod acceleration of±0.675 m/s^(2) when operating at a stroke of 6 min^(−1).When deployed in two wells,the root-mean-square(RMS)torque was minimized,reaching values of 7.539 kN·m and 12.921 kN·m,respectively.The proposed design method not only contributes to the personalized customization but also improves the design efficiency of compound balanced BPUs.
文摘The optimization of civil engineering structures is critical for enhancing structural performance and material efficiency in engineering applications.Structural optimization approaches seek to determine the optimal design,by considering material performance,cost,and structural safety.The design approaches aim to reduce the built environment’s energy use and carbon emissions.This comprehensive review examines optimization techniques,including size,shape,topology,and multi-objective approaches,by integrating these methodologies.The trends and advancements that contribute to developing more efficient,cost-effective,and reliable structural designs were identified.The review also discusses emerging technologies,such as machine learning applications with different optimization techniques.Optimization of truss,frame,tensegrity,reinforced concrete,origami,pantographic,and adaptive structures are covered and discussed.Optimization techniques are explained,including metaheuristics,genetic algorithm,particle swarm,ant-colony,harmony search algorithm,and their applications with mentioned structure types.Linear and non-linear structures,including geometric and material nonlinearity,are distinguished.The role of optimization in active structures,structural design,seismic design,form-finding,and structural control is taken into account,and the most recent techniques and advancements are mentioned.
基金supported by Scientific Research Project of Guangdong Provincial Department of Education(2024KQNCX152).
文摘Flow velocity uniformity of the microchannel plate is a major factor affecting the performance of microchannel devices.In order to improve the velocity distribution uniformity of the microchannel plate,we designed two new microchannel structures:V-type and A-type.The effects of various structural parameters of the manifolds on the velocity distribution are reported.The V-type and A-type microchannel plates had a more uniform velocity distribution compared to the Z-type microchannel plate.The final result showed that it is beneficial for the V-type microchannel plate to obtain a more uniform velocity distribution when the manifold structure parameters are X_(in)=-1,X_(out)=0,Y_(in)=10,Y_(out)=6,Hin=4,H_(out)=1,and R=0.5.
基金supported by the Yuxiu Innovation Project of NCUT(Grant No.2024NCUTYXCX211).
文摘Purpose–This paper aims to provide a comprehensive analysis of the strategic adjustments in China’s transportation structure,with a particular focus on the pivotal role of railway freight and its integration into the modern logistics system.It seeks to address the need for a more nuanced understanding of the“road to rail”policy,emphasizing the importance of intermodal collaboration and service of fragmented market demands.Design/methodology/approach–The study employs a transport economics perspective to evaluate the achievements and shortcomings of China’s transportation structure optimization.It bases its assessment of the current state of railway freight logistics,multi-modal transportation and the broader implications for the transportation service market on data analysis.The methodology includes a review of existing policies,an examination of industry practices and a comparative analysis with global trends in railway logistics.Findings–The research underscores the importance of focusing on the development of non-bulk materials,noting the insufficiency in the development of China’s rail multi-modal transportation and highlighting the instructive value of successful cases in open-top container road-rail intermodal transportation.The study posits that the railway sector must enhance cooperation with other market entities,aligning with the lead enterprises in the logistics chain that are characterized by speed,high value and strong coordination capabilities,in order to better serve the transportation market.This approach moves away from a reliance on the railway’s own capabilities alone.Originality/value–This paper offers original insights into the transformation of railway freight in China,contributing to the body of knowledge on transportation economics and logistics.It provides valuable recommendations for policymakers and industry practitioners,emphasizing the strategic importance of railway logistics in the context of China’s economic development and intense competition in the supply chain.The value of the article lies in its comprehensive understanding of the complexities involved in the adjustment of transportation structures,providing direction for the market-oriented reform of China’s railway freight sector.
文摘In this paper,the front axle of a certain model is taken as the research object,and the stress and deformation of the frontaxle under three typical working conditions are analyzed by finite element technology.Based on the simulation results,the 3D model of the front axle was optimized,and the finite element analysis of the optimized structure of the front axle under three typical working conditions was carried out to verify the correctness of the model.Finally,the fatigue tool module of ANSYS Workbench was used to analyze the fatigue life of the front axle under the optimized emergency conditions,and the feasibility of the model was verified.The analysis data shows that the design of the front axle components still has a lot of potential for lightweighting,and the weight of the front axle can be reduced by 6.73%through optimization,and the performance of the front axle can also meet the needs of use.The research conclusionhas a certain reference value for the lightweight design of automobile front axle.
基金Project of Hunan Federation of Social Sciences,“Research on the Coupling Coordination Relationship between Green Finance and Industrial Structure Optimization in Hunan Province”(Project No.:XSP2023GLC027)。
文摘Green finance,as an important policy to promote high-quality economic development,has become a focus of attention in the academic and policy circles for its promotion of industrial structure optimization.Based on the data of six provinces in Central China from 2010 to 2023,this paper constructs a comprehensive index of green finance development by using entropy value method and empirically analyses the impact of green finance on industrial structure optimization.The results show that the level of green finance development has a significant contribution to the optimization of the industrial structure in the central region.Accordingly,this study provides suggestions for deepening green finance reform and accelerating industrial transformation and upgrading.
基金The Impact of Digital Economy on Green Development Efficiency.2025 Nanjing University of Science and Technology Zijin College Campus Level Scientific Research Project(Project No.:2025ZXSK0401011)。
文摘Under the background of this era,green finance and the upgrading and optimization of industrial structure have become a hot research topic.The article focuses on Jiangsu Province,carefully explores the impact of green financial development on the upgrading and optimization of industrial structure and the real effect,collates and summarizes the theories of green finance and industrial structure at home and abroad,and carefully analyzes the development of green finance in Jiangsu Province,such as the gradual expansion of green credit scale,the characteristics of industrial structure,the change of the proportion of three industries,the development situation of emerging industries and so on.By means of econometrics,an empirical model covering Green Financial Development Indicators and industrial structure optimization indicators is established to do multiple linear regression analysis and stability test.The empirical results show that the development of green finance in Jiangsu plays an obvious positive role in the optimization and upgrading of industrial structure.Green finance is environmental protection,new energy and other green industries are given important financial support,which drives their scale expansion and technological innovation,and makes the industrial structure develop towards a higher level and a more reasonable direction.From this point of view,corresponding proposals are put forward to improve the policy incentive system,add green financial products,and strengthen the construction of green financial market.The purpose is to give better play to the advantages of green finance,accelerate the optimization and upgrading of industrial structure in Jiangsu,and provide theoretical basis and practical guidance for achieving green economic transformation and sustainable development.
文摘Build-up panels for the commercial aircraft fuselage subjected to the axial compression load are studied by both experimental and theoretical methods.An integral panel is designed with the same overall size and weight as the build-up structure,and finite element models（FEMs）of these two panels are established.Experimental results of build-up panels agree well with the FEM results with the nonliearity and the large deformation,so FEMs are validated.FEM calculation results of these two panels indicate that the failure mode of the integral panel is different from that of the build-up panel,and the failure load increases by 18.4% up to post-buckling.Furthermore,the integral structure is optimized by using the multi-island genetic algorithm and the sequential quadratic programming.Compared with the initial design,the optimal mass is reduced by 8.7% and the strength is unchanged.
基金The project supported by the State Key Laboratory for Structural Analysis of Industrial Equipment,Dalian University of Technology.
文摘A new exist-null combined model is proposed for the structural topology optimization. The model is applied to the topology optimization of the truss with stress constraints. Satisfactory computational result can be obtained with more rapid and more stable convergence as compared with the cross-sectional optimization. This work also shows that the presence of independent and continuous topological variable motivates the research of structural topology optimization.
基金Under the auspices of National Natural Science Foundation of China(No.41401627,41471144)Foundation Research Project of Jiangsu Province(No.BK20140236)
文摘Land use structure optimization(LUSO) is an important issue for land use planning. In order for land use planning to have reasonable flexibility, uncertain optimization should be applied for LUSO. In this paper, the researcher first expounded the uncertainties of LUSO. Based on this, an interval programming model was developed, of which interval variables were to hold land use uncertainties. To solve the model, a heuristics based on Genetic Algorithm was designed according to Pareto Optimum principle with a confidence interval under given significance level to represent LUSO result. Proposed method was applied to a real case of Yangzhou, an eastern city in China. The following conclusions were reached. 1) Different forms of uncertainties ranged from certainty to indeterminacy lay in the five steps of LUSO, indicating necessary need of comprehensive approach to quantify them. 2) With regards to trade-offs of conflicted objectives and preferences to uncertainties, our proposed model displayed good ability of making planning decision process transparent, therefore providing an effective tool for flexible land use planning compiling. 3) Under uncertain conditions, land use planning effectiveness can be primarily enhanced by flexible management with reserved space to percept and hold uncertainties in advance.
文摘Sintering characteristics of common fluxes and sintering blending ores, such as mineralization capacity, liquid generation capacity, consolidation strength, were examined to master the behavior and effect of fluxes in sintering. Based on fundamental studies, sinter pot tests were carried out to obtain the principles of optimizing the sinter flux structure. The results showed that strong mineralization capacity, liquid phase generation capacity, and consolidation strength were obtained as sintering blending ores combined with the calcareous flux, while rela-tively poor sintering characteristics were obtained as sintering blending ores combined with the magnesian flux. High reactive quicklime should be used as much as possible in the sintering mixture. It reached better sintering results while quicklime was used instead of limestone and its appropriate proportion in the sintering mixture was around 4wt%. On the premise of ensuring the MgO content, the dolomite amount should be decreased, and the substitution of quicklime for dolomite caused better sintering results. The granularity of serpentine should be re-fined with a proper size smaller than 2 mm. The application of the divided addition method brought the best sintering performance with 30wt% of quicklime and 70wt% of fuel.
基金supported by the National Natural Science Foundation of China (No. 11172025 and No. 91116005)
文摘An aeroelastic two-level optimization methodology for preliminary design of wing struc- tures is presented, in which the parameters for structural layout and sizes are taken as design vari- ables in the first-level optimization, and robust constraints in conjunction with conventional aeroelastic constraints are considered in the second-level optimization. A low-order panel method is used for aerodynamic analysis in the first-level optimization, and a high-order panel method is employed in the second-level optimization. It is concluded that the design of the abovementioned structural parameters of a wing can be improved using the present method with high efficiency. An improvement is seen in aeroelastic performance of the wing obtained with the present method when compared to the initial wing. Since these optimized structures are obtained after consideration of aerodynamic and structural uncertainties, they are well suited to encounter these uncertainties when they occur in reality.
基金financially supported by National Natural Science Foundation of China(No.52174009 and No.51827804)Marine Economy Development Foundation of Guangdong Province(GDNRC[2022]44)“Technical Support for Stimulation and Testing of Gas Hydrate Reservoirs”.
文摘Cavitating jet is a promising drilling rate improvement technology in both the marine natural gas hydrate (NGH) fluidization exploitation method and the integrated radial jet drilling and completion method. In present study, we aim to improve the efficiency of jet erosion and extracting NGH. With a computational fluid dynamics (CFD) method, the pressure, velocity and cavitation field characteristics of organ-pipe cavitating jet (OPCJ) are analysed. The divergent angle, throat length, and divergent length of OPCJ nozzle are preferred to obtain stronger jet cavitation erosion effect. Laboratory experiments of gas hydrate-bearing sediments (GHBS) erosion by OPCJ and conical jet (CJ) are conducted to compare and validate the jet erosion performance. The impinging models of OPCJ and CJ are constructed to study the impact characteristics. Results show that the preferred values of divergent angle, throat length, and divergent length are 15°, 1d, and 3d, respectively, in present simulation conditions. For GHBS, the OPCJ possesses the advantages of high efficiency and low energy consumption. Moreover, the OPCJ has higher penetration efficiency, while showing equivalent penetration ability compared to CJ. During the impinging process, the OPCJ can induce stronger impact pressure and turbulence effect, and also shows stronger chambering effect and bottom cleaning ability compared to CJ. This study presents the erosion performance of OPCJ and CJ on GHBS, and provides preliminary insights on the potential field applications in NGH exploitation.
基金funded by the National Natural Science Foundation of China (41130748, 41101162)the Key Knowledge Innovation Project of Chinese Academy of Sciences (KZCX2-EW-304)
文摘A large number of mathematical models were developed for supporting agricultural production structure optimization decisions; however, few of them can address various uncertainties existing in many factors （e.g., eco-social benefit maximization, food security, employment stability and ecosystem balance）. In this study, an interval-probabilistic agricultural production structure optimization model （IPAPSOM） is formulated for tackling uncertainty presented as discrete intervals and/or probability distribution. The developed model improves upon the existing probabilistic programming and inexact optimization approaches. The IPAPSOM considers not only food security policy constraints, but also involves rural households’income increase and eco-environmental conversation, which can effectively reflect various interrelations among different aspects in an agricultural production structure optimization system. Moreover, it can also help examine the reliability of satisfying （or risk of violating） system constraints under uncertainty. The model is applied to a real case of long-term agricultural production structure optimization in Dancheng County, which is located in Henan Province of Central China as one of the major grain producing areas. Interval solutions associated with different risk levels of constraint violation are obtained. The results are useful for generating a range of decision alternatives under various system benefit conditions, and thus helping decision makers to identify the desired agricultural production structure optimization strategy under uncertainty.
