To accelerate the large-scale integration of renewable energy and support the strategic goals of“carbon peaking and carbon neutrality,”High Voltage Direct Current(HVDC)transmission technology has made significant br...To accelerate the large-scale integration of renewable energy and support the strategic goals of“carbon peaking and carbon neutrality,”High Voltage Direct Current(HVDC)transmission technology has made significant breakthroughs.Among the various approaches,a hybrid DC transmission system that combines a line-commutated converter(LCC)and a voltage source converter(VSC)retains the inherent fault self-clearing capability of the LCC topology while mitigating the risk of commutation failure when connected to a weak grid.In this paper,based on the harmonic generation mechanisms of hybrid DC transmission systems,an improved 3-pulse harmonic source model of the LCC and a dynamic phase-sequence harmonic analysis model of the VSC are developed.The integrated harmonic model demonstrates strong adaptability in accurately calculating DC-side harmonics under the influence of power imbalances and background harmonics.Based on this model,the fundamental characteristics of DC-side harmonics in hybrid DC transmission systems are analyzed.To mitigate harmonic effects,this paper proposes an LCLC-trap2 high-order filter structure with parallel RC damping circuits and a co-optimized design of filter parameters.Finally,a±500 kV hybrid DC transmission systemismodeled using theMATLAB/Simulink platform,and the harmonic filtering performances of the conventional LC filter,the Butterworth filter,and the proposed filter are simulated and compared.The results verify that the proposed filter offers superior performance in suppressing low-order harmonics under nonideal operating conditions.展开更多
[Introduction] Accurate calculation of the hydrodynamic coefficients for floating structures and the investigation of the flow field distribution around floating bodies on the marine free surface are essential for imp...[Introduction] Accurate calculation of the hydrodynamic coefficients for floating structures and the investigation of the flow field distribution around floating bodies on the marine free surface are essential for improving the engineering design and application of marine structures.[Method] This study utilized the computational fluid dynamics(CFD) approach and the Reynolds Averaged NavierStokes(RANS) method and considered the effects of viscosity and free surface interactions on the hydrodynamic behavior of floating structures.By employing the dynamic mesh technique,this study simulated the periodic movements of simplified three-dimensional(3D)shapes:spheres,cylinders,and cubes,which were representative of complex marine structures.The volume of fluid(VOF) method was leveraged to accurately track the nonlinear behavior of the free surface.In this analysis,the added mass and damping coefficients for the fundamental modes of motion(surge,heave,and roll) were calculated across a spectrum of frequencies,facilitating the fast determination of hydrodynamic forces and moments exerted on floating structures.[Result] The results of this study are not only consistent with the results of the 3D potential flow theory but also further reflect the role of viscosity.This method can be used for precise calculation of the hydrodynamic coefficients of floating structures and for describing the flow field of such structures in motion on a free surface.[Conclusion] The methodology presented goes beyond the traditional potential flow approach.展开更多
To overcome the limitations of structural height imposed by airspace restrictions in the design of maintenance hangar roofs with long spans,a new diagonal truss roof structural system is introduced for the first time....To overcome the limitations of structural height imposed by airspace restrictions in the design of maintenance hangar roofs with long spans,a new diagonal truss roof structural system is introduced for the first time.In the design of China Southern Airlines No.1 Hangar,4 main trusses were arranged diagonally along the depth direction,forming a W-shape truss.3 lineshaped trusses were arranged along the span direction,and double-layer space latticed structure is laid on them.The design optimized the height of the 183 m+222 m super long-span roof to 11.5 m,the maximum dimension the site could provide,so that the building height is within the permitted 40m.The steel consumption of the roof is only 165 kg/m^(2).The installation of diagonal trusses changed the unidirectional load transmission path of the roof and enhanced the spatial load transmission,effectively relieving the burden on the gate-side truss.This design enables the implementation of a maintenance hangar with a 222 m-span and heavy roof within the constraints of low airspace height.展开更多
To quantify the seismic effectiveness of the most commonly used fishing line tie up method for securing museum collections and optimize fixed strategies for exhibitions,shaking table tests of the seismic systems used ...To quantify the seismic effectiveness of the most commonly used fishing line tie up method for securing museum collections and optimize fixed strategies for exhibitions,shaking table tests of the seismic systems used for typical museum collection replicas have been carried out.The influence of body shape and fixed measure parameters on the seismic responses of replicas and the interaction behavior between replicas and fixed measures have been explored.Based on the results,seismic effectiveness evaluation indexes of the tie up method are proposed.Reasonable suggestions for fixed strategies are given,which provide a basis for the exhibition of delicate museum collections considering the principle of minimizing seismic responses and intervention.The analysis results show that a larger ratio of height of mass center to bottom diameter led to more intense rocking responses.Increasing the initial pretension of fishing lines was conducive to reducing the seismic responses and stress variation of the lines.Through comprehensive consideration of the interaction forces and effective securement,it is recommended to apply 20%of breaking stress as the initial pretension.For specific museum collections that cannot be effectively protected by the independent tie up method,an optimized strategy of a combination of fishing lines and fasteners is recommended.展开更多
The paper establishes a multidisciplinary design and optimization framework that aims at minimizing Unmanned aerial vehicles (UAV) development costs. This framework integrates development costs as an equally important...The paper establishes a multidisciplinary design and optimization framework that aims at minimizing Unmanned aerial vehicles (UAV) development costs. This framework integrates development costs as an equally important factor alongside weight and aerodynamic disciplines within the UAV design process. The OpenMDAO paradigm is employed to facilitate a standalone design and optimization application. A comprehensive multidisciplinary analysis module is developed, encompassing initial geometrical sizing, weight analysis, aerodynamic performance evaluation, and estimation models for development costs. The effectiveness of the framework is validated through a low-cost, high-performance UAV case study. The results demonstrate that neglecting the influence of UAV development costs would be imprudent. By appropriately adjusting design parameters using the optimization algorithm, significant reductions in UAV development costs can be achieved with minimal performance losses.展开更多
With the rapid development of urban construction,the land around mountains has unique resource and environmental advantages,so that the land around mountains become a rare resource for development and construction.To ...With the rapid development of urban construction,the land around mountains has unique resource and environmental advantages,so that the land around mountains become a rare resource for development and construction.To make scientific use of land resources around mountains and avoid excessive and disorderly development of mountains,it is particularly important to protect and control mountain resources.Xuzhou City is rich in mountain forest resources.In this paper,from the perspective of urban design,the construction control of land around mountains in Xuzhou City is studied and explored,and the requirements and methods for the detailed planning and urban design of plots around important mountains are put forward from the aspects of mountain protection classification,control principles of the height of buildings around mountains,and control principles of construction and development intensity of plots around mountains.展开更多
Green energy conservation is the mainstream trend in the current development of the construction industry.The application of energy-saving technology in building electrical system design can effectively reduce energy ...Green energy conservation is the mainstream trend in the current development of the construction industry.The application of energy-saving technology in building electrical system design can effectively reduce energy consumption,avoid unnecessary energy consumption,and truly achieve energy conservation and environmental protection.Based on this,the article elaborates on the principles of energy-saving design in building electrical systems,and actively explores the application of energy-saving technologies from different perspectives such as optimizing power supply and distribution system design,adopting high-efficiency energy-saving lighting equipment,applying renewable energy,promoting smart home technology,and improving the efficiency of building electrical equipment.展开更多
Waterproof performance of gaskets between segments is the focus of shield tunnels.This paper proposed an analytical method for determining seepage characteristics at tunnel-gasketed joints based on the hydraulic fract...Waterproof performance of gaskets between segments is the focus of shield tunnels.This paper proposed an analytical method for determining seepage characteristics at tunnel-gasketed joints based on the hydraulic fracturing theories.First,the mathematical model was established,and the seepage governing equation and boundary conditions were obtained.Second,three dimensionless parameters were introduced for simplifying the expressions,and the seepage governing equations were normalized.Third,analytical expressions were derived for the interface opening and liquid pressure.Moreover,the influencing factors of seepage process at the gasketed interface were analyzed.Parametric analyses revealed that,in the normalized criterion of liquid viscosity,the liquid tip coordinate was influenced by the degree of negative pressure in the liquid lag region,which was related to the initial contact stress.The coordinate of the liquid tip affected the liquid pressure distribution and the interface opening,which were analyzed under different liquid tip coordinate conditions.Finally,under two limit states,comparative analysis showed that the results of the variation trend of the proposed method agree well with those of previous research.Overall,the proposed analytical method provides a novel solution for the design of the waterproof in shield tunnels.展开更多
The vibration response and noise caused by subway trains can affect the safety and comfort of superstructures.To study the dynamic response characteristics of subway stations and superstructures under train loads with...The vibration response and noise caused by subway trains can affect the safety and comfort of superstructures.To study the dynamic response characteristics of subway stations and superstructures under train loads with a hard combination,a numerical model is developed in this study.The indoor model test verified the accuracy of the numerical model.The influence laws of different hard combinations,train operating speeds and modes were studied and evaluated accordingly.The results show that the frequency corresponding to the peak vibration acceleration level of each floor of the superstructure property is concentrated at 10–20 Hz.The vibration response decreases in the high-frequency parts and increases in the lowfrequency parts with increasing distance from the source.Furthermore,the factors,such as train operating speed,operating mode,and hard combination type,will affect the vibration of the superstructure.The vibration response under the reversible operation of the train is greater than that of the unidirectional operation.The operating speed of the train is proportional to its vibration response.The vibration amplification area appears between the middle and the top of the superstructure at a higher train speed.Its vibration acceleration level will exceed the limit value of relevant regulations,and vibration-damping measures are required.Within the scope of application,this study provides some suggestions for constructing subway stations and superstructures.展开更多
[Objective]The channel straightening project of the Pinglu Canal has fragmented the river course,compromising the integrity of original river course and causing ecosystem patchiness.Understanding the current status of...[Objective]The channel straightening project of the Pinglu Canal has fragmented the river course,compromising the integrity of original river course and causing ecosystem patchiness.Understanding the current status of fish resources and the characteristics of their diversity is crucial for the ecological management of the Pinglu Canal.[Methods]During the spring and autumn in 2021 and 2022,a survey of fish resources and species diversity in the Pinglu Canal was conducted using multi-mesh gill nets.A total of 125 fish species were collected,belonging to 10 orders,34 families,and 89 genera.[Results]The result showed that the Pinglu Canal contained three nationally protected Class II species,two endemic species of the Qinjiang River,three anadromous/migratory species,and eight invasive species,accounting for 2.4%,1.6%,2.4%,and 6.4%of the total species,respectively.The fish community primarily consisted of mid-and bottom-dwelling,adhesive-egg-laying,and omnivorous species.The Shannon-Wiener,Simpson,Margalef,and Pielou indices of the fish community in the Pinglu Canal ranged from 2.347 to 2.757,0.081 to 0.151,3.493 to 4.382,and 0.812 to 0.892,respectively.These indices showed relatively uniform distribution across different river reaches.[Conclusion]The result indicate that the fish community structure in the Pinglu Canal is relatively uniform.The reach from the Yujiang River to the Shaping River shows higher stability,while other river reaches experience moderate or severe disturbances.This study provides supplementary baseline data on the fish community structure in the Pinglu Canal and explores the potential impact of inter-basin connectivity on fish resources,aiming to provide a scientific basis for habitat restoration assessments after the channel straightening project.展开更多
To study the development of imbibition such as the imbibition front and phase distribution in shale,the Lattice Boltzmann Method(LBM)is used to study the imbibition processes in the pore-throat network of shale.Throug...To study the development of imbibition such as the imbibition front and phase distribution in shale,the Lattice Boltzmann Method(LBM)is used to study the imbibition processes in the pore-throat network of shale.Through dimensional analysis,four dimensionless parameters affecting the imbibition process were determined.A color gradient model of LBM was used in computation based on a real core pore size distribution.The numerical results show that the four factors have great effects on imbibition.The impact of each factor is not monotonous.The imbibition process is the comprehensive effect of all aspects.The imbibition front becomes more and more non-uniform with time in a heterogeneous pore-throat network.Some non-wetting phases(oil here)cannot be displaced out.The displacement efficiency and velocity do not change monotonously with any factor.The development of the average imbibition length with time is not smooth and not linear in a heterogeneous pore-throat network.Two fitting relations between the four dimensionless parameters and the imbibition velocity and efficiency are obtained,respectively.展开更多
[Objective]Implementation of the Ten-Year Fishing Ban policy may alter fish diversity and niche characteristics of dominant species in spawning grounds within the National Nature Reserve for Rare and Endemic Fish in t...[Objective]Implementation of the Ten-Year Fishing Ban policy may alter fish diversity and niche characteristics of dominant species in spawning grounds within the National Nature Reserve for Rare and Endemic Fish in the Upper Yangtze River.This study initiated continuous monitoring of natural spawning habitats from February 2022 to assess these ecological changes.[Methods]Environmental DNA(eDNA)metabarcoding was employed to analyze fish species composition,biodiversity patterns,and niche parameters of dominant species.Water sampling followed the CEN/TS 19461 standard across five monitoring transects(ZT1-ZT5).[Results]The eDNA analysis detected 45 species of fish belonging to 38 genera,13 families,and 3 orders were detected through environmental DNA(eDNA)in this survey,including 10 species endemic to the upper reaches of the Yangtze River,such as Procypris rabaudi and Myxocyprinus asiaticus.The fish community was mainly composed of bottom-dwelling,settling ovum-producing,omnivorous fish.The variation ranges of the Chao1 index,ACE index,Shannon index,and Simpson index are 736~996,719~965,1.58~3.23,and 0.83~0.99,respectively,indicating that fish species in spawning sites are abundant and community distribution uniformity is high.All indexes are highest at ZT1 monitoring points.Cluster analysis showed that,at a certain similarity level,fish community types in spawning sites could be basically divided into two groups:ZT1,ZT3,and ZT5 clustered together,and ZT2 and ZT4 clustered together,indicating similar fish community habitats.There are 9 dominant fish species in typical deep pool habitats in the reserve,with niche widths(Bi)ranging from 1.13 to 3.87.The dominant fish species are broad and medium niche fish,such as Cyprinus carpio and Hemiculter tchangi,with the niche overlap index(Oik)of some dominant fish species reaching more than 0.95.This indicates fierce competition for resources among the fish in this spawning ground.[Conclusion]The Zhutuo spawning ground demonstrates high species richness with homogeneous community structure and intense resource competition.This study establishes an eDNA-based monitoring framework that enhances conventional survey method,providing critical baseline data for adaptive management under the fishing moratorium regime.展开更多
Graphene oxide nanomaterials are increasingly used in various fields due to their superior properties.In order to study the influence of graphene oxide additives on the performance of modified asphalt,in this study,gr...Graphene oxide nanomaterials are increasingly used in various fields due to their superior properties.In order to study the influence of graphene oxide additives on the performance of modified asphalt,in this study,graphene oxide modified asphalt was prepared and characteristics was studied including the high deformation resistance performance and the self-healing property of modified asphalt.Functional groups and morphology of graphene oxide modified asphalt were described by Fourier transform infrared spectroscopy.The high deformation resistance performance and self-healing effect of asphalt samples were obtained through dynamic slear rheometer(DSR)test.Results shows that graphene oxide dispersions improve the performance of asphalt relatively well compared to graphene oxide powder.There is no chemical reaction between graphene oxide and asphalt,but physical connection.The addition of graphene oxide improved the high deformation resistance of modified asphalt and expedited the self-healing ability of asphalt under fatigue load.展开更多
Purpose–The bridge expansion joint(BEJ)is a key device for accommodating spatial displacement at the beam end,and for providing vertical support for running trains passing over the gap between the main bridge and the...Purpose–The bridge expansion joint(BEJ)is a key device for accommodating spatial displacement at the beam end,and for providing vertical support for running trains passing over the gap between the main bridge and the approach bridge.For long-span railway bridges,it must also be coordinated with rail expansion joint(REJ),which is necessary to accommodate the expansion and contraction of,and reducing longitudinal stress in,the rails.The main aim of this study is to present analysis of recent developments in the research and application of BEJs in high-speed railway(HSR)long-span bridges in China,and to propose a performance-based integral design method for BEJs used with REJs,from both theoretical and engineering perspectives.Design/methodology/approach–The study first presents a summary on the application and maintenance of BEJs in HSR long-span bridges in China representing an overview of their state of development.Results of a survey of typical BEJ faults were analyzed,and field testing was conducted on a railway cable-stayed bridge in order to obtain information on the major mechanical characteristics of its BEJ under train load.Based on the above,a performance-based integral design method for BEJs with maximum expansion range 1600 mm(±800 mm),was proposed,covering all stages from overall conceptual design to consideration of detailed structural design issues.The performance of the novel BEJ design thus derived was then verified via theoretical analysis under different scenarios,full-scale model testing,and field testing and commissioning.Findings–Two major types of BEJs,deck-type and through-type,are used in HSR long-span bridges in China.Typical BEJ faults were found to mainly include skewness of steel sleepers at the bridge gap,abnormally large longitudinal frictional resistance,and flexural deformation of the scissor mechanisms.These faults influence BEJ functioning,and thus adversely affect track quality and train running performance at the beam end.Due to their simple and integral structure,deck-type BEJs with expansion range 1200 mm(±600 mm)or less have been favored as a solution offering improved operational conditions,and have emerged as a standard design.However,when the expansion range exceeds the above-mentioned value,special design work becomes necessary.Therefore,based on engineering practice,a performance-based integral design method for BEJs used with REJs was proposed,taking into account four major categories of performance requirements,i.e.,mechanical characteristics,train running quality,durability and insulation performance.Overall BEJ design must mainly consider component strength and the overall stiffness of BEJ;the latter factor in particular has a decisive influence on train running performance at the beam end.Detailed BEJ structural design must stress minimization of the frictional resistance of its sliding surface.The static and dynamic performance of the newlydesigned BEJ with expansion range 1600 mm have been confirmed to be satisfactory,via numerical simulation,full-scale model testing,and field testing and commissioning.Originality/value–This research provides a broad overview of the status of BEJs with large expansion range in HSR long-span bridges in China,along with novel insights into their design.展开更多
A group optimal penetration strategy in complex attack and defense confrontation situation is proposed in this paper to solve the coordinated penetration decision-making problem of endo-atmospheric gliding simultaneou...A group optimal penetration strategy in complex attack and defense confrontation situation is proposed in this paper to solve the coordinated penetration decision-making problem of endo-atmospheric gliding simultaneous multi-missile penetration of interceptors.First,the problem of large search space of multi-missile coordinated penetration maneuvers is fully considered,and the flight corridor of multi-missile coordinated penetration is designed to constrain search space of multi-agent coordinated strategy,comprehensively considering path constraints and anticollision constraints of gliding multi-missile flight.Then,a multi-missile hierarchical coordinated decision-making mechanism based on confrontation situation is proposed,and the swarm penetration strategy is optimized with the goal of maximizing swarm penetration effectiveness.The upper layer plans the swarm penetration formation according to confrontation situation,and generates the swarm coordinated penetration trajectory based on Multi-Agent Deep Deterministic Policy Gradient(MADDPG)method.The lower layer interpolates and smooths penetration trajectory,and generates the penetration guidance command based on Soft Actor-Critic and Extended Proportional Guidance(SAC-EPG)method.Simulation results verify that the proposed multi-missile cooperative penetration method based on hierarchical reinforcement learning converges faster than the penetration method based on MADDPG,and can quickly learn multi-missile cooperative penetration skills.In addition,multi-missile coordination can give full play to the group's detection and maneuverability,and occupy favorable penetration time and space through coordinated ballistic maneuvers.Thus the success rate of group penetration can be improved.展开更多
Cyclic wetting-drying alternation has a significant influence on the strength and structure of soils.It is prone to causing soil softening and disintegration,highlighting the importance to improve the soil's resis...Cyclic wetting-drying alternation has a significant influence on the strength and structure of soils.It is prone to causing soil softening and disintegration,highlighting the importance to improve the soil's resistance to disintegration.This paper utilizes a self-developed disintegration test apparatus to analyze the disintegration characteristics of improved red soil under wet-dry cycles,focusing on the disintegration amount and ratio.Furthermore,XRD(X-ray diffraction),SEM(scanning electron microscope),tensile test,and contact angle test are employed to investigate the anti-disintegration behaviors of the improved red soil.The results show that the disintegrating amount and ratio of undisturbed and improved red soil are distinctly different under wet-dry cycles.Linear,stepped,constant and concave but perfect"S"shapes of the disintegrating ratio are observed in the cyclic tests.Cement and lime strengthen the red soil primarily through hydration reaction.The drop experiment confirms that cement plays a crucial role in restraining the disintegration.When the ameliorant content is low,the correlation between pore parameters and disintegration duration of red soil follows the order:mean shape coefficient>fractal dimension>probability entropy>area probability distribution index.With a high ameliorant content,the correlation remains similar,with slightly higher correlation for probability entropy.Under wet-dry cycle conditions,sludge and kaolin can improve the soil through the bonding of clay particles.The improved water repellency greatly enhances the resistance to disintegration of the altered red soil.The research provides valuable insights for the practical application of soil.展开更多
An intelligent endo-atmospheric penetration strategy based on generative adversarialreinforcement learning is proposed in this manuscript.Firstly,attack and defense adversarial mod-els are established,and missile mane...An intelligent endo-atmospheric penetration strategy based on generative adversarialreinforcement learning is proposed in this manuscript.Firstly,attack and defense adversarial mod-els are established,and missile maneuver penetration problem is transformed into an optimal con-trol problem,considering penetration,handover position and mid-terminal guidance velocityconstraints.Then,Radau Pseudospectral method is adopted to generate data samples consideringrandom perturbations.Furthermore,Generative Adversarial Imitation Learning Combined withDeep Deterministic Policy Gradient method(GAIL-DDPG)is designed,with internal processreward signals constructed to tackle long-term sparse reward in missile manuver penetration prob-lem.Finally,penetration strategy is trained and verified.Simulation shows that using generativeadversarial reinforcement learning,with sample library to learn expert experience in training earlystage,the proposed method can quickly converge.Also,performance is further optimized with rein-forcement learning exploration strategy in the later stage of training.Simulation shows that the pro-posed method has better engineering application ability compared with traditional reinforcementlearning method.展开更多
Background:The use of grafts from donation after circulatory death(DCD)overcomes the inadequate donor organ supply.Our team developed a transportable dual hypothermic oxygenated machine perfusion(DHOPE)device,which in...Background:The use of grafts from donation after circulatory death(DCD)overcomes the inadequate donor organ supply.Our team developed a transportable dual hypothermic oxygenated machine perfusion(DHOPE)device,which initiates DHOPE at a recipient center to reduce static cold storage(SCS)time and the risk of graft failure in DCD liver transplantation.Methods:Six porcine livers per group with 30 min of warm ischemia exposure were preserved via SCS or DHOPE for 6 h and then reperfused for 12 h with whole blood to mimic transplantation.Hepatocellular and biliary function and injury were assessed in perfusate and bile samples.Molecular biomarkers and histology were compared between groups.Results:Reperfusion portal vein pressure,in a flow-constant manner,and alanine aminotransferase(ALT),aspartate aminotransferase(AST),alkaline phosphatase(ALP)and gamma-glutamyltransferase(γ-GGT)release were significantly lower in the DHOPE group than in the SCS group at all time points.Higher bile production paralleled the lower levels of ALP andγ-GGT in the DHOPE group.The DHOPE group secreted more total bilirubin(TBIL)in bile,resulting in decreased TBIL in the perfusate,and livers preserved with DHOPE exhibited better cholangiocellular function.Furthermore,improvements in hypoxia,the inflammatory response,cell-free microRNAs and energy metabolism were observed in the DHOPE group.There were fewer apoptotic cells and TGF-β1-positive cells in the liver parenchyma and extrahepatic bile duct in the DHOPE group than in the SCS group.Conclusions:This study demonstrates the efficacy of local 4℃DHOPE to protect porcine liver grafts from30-min warm ischemia damage.展开更多
In recent years,decomposition-based evolutionary algorithms have become popular algorithms for solving multi-objective problems in real-life scenarios.In these algorithms,the reference vectors of the Penalty-Based bou...In recent years,decomposition-based evolutionary algorithms have become popular algorithms for solving multi-objective problems in real-life scenarios.In these algorithms,the reference vectors of the Penalty-Based boundary intersection(PBI)are distributed parallelly while those based on the normal boundary intersection(NBI)are distributed radially in a conical shape in the objective space.To improve the problem-solving effectiveness of multi-objective optimization algorithms in engineering applications,this paper addresses the improvement of the Collaborative Decomposition(CoD)method,a multi-objective decomposition technique that integrates PBI and NBI,and combines it with the Elephant Clan Optimization Algorithm,introducing the Collaborative Decomposition Multi-objective Improved Elephant Clan Optimization Algorithm(CoDMOIECO).Specifically,a novel subpopulation construction method with adaptive changes following the number of iterations and a novel individual merit ranking based onNBI and angle are proposed.,enabling the creation of subpopulations closely linked to weight vectors and the identification of diverse individuals within them.Additionally,new update strategies for the clan leader,male elephants,and juvenile elephants are introduced to boost individual exploitation capabilities and further enhance the algorithm’s convergence.Finally,a new CoD-based environmental selection method is proposed,introducing adaptive dynamically adjusted angle coefficients and individual angles on corresponding weight vectors,significantly improving both the convergence and distribution of the algorithm.Experimental comparisons on the ZDT,DTLZ,and WFG function sets with four benchmark multi-objective algorithms—MOEA/D,CAMOEA,VaEA,and MOEA/D-UR—demonstrate that CoDMOIECO achieves superior performance in both convergence and distribution.展开更多
The geological disasters such as collapse,mud bursting and water gushing often occur during tunnel construction.Thus,it is of great significance to detect the hidden geological disasters ahead of the tunnel face.The a...The geological disasters such as collapse,mud bursting and water gushing often occur during tunnel construction.Thus,it is of great significance to detect the hidden geological disasters ahead of the tunnel face.The audio magnetotelluric(AMT)was applied for the advanced detectionstudy during the boring process of the Tianheshan tunnel in the Taihang Mountains.Three AMT profiles were deployed above the tunnel,and the data obtained in the field were analysed in terms of electrical principal axes.From shallow to deep,the direction of the geoelectric strike angle changes,generally between 30°and 60°NE,which is consistent with similar to the direction of the Taihangshan Uplift,and the data show some 3D characteristics.Two-dimensional(2D)and three-dimensional(3D)inversion methods were adopted to jointly study the subsurface structural information,and the resistivity model was geophysically and geologically interpreted.Two sets of low resistance anomalies were found,and it was hypothesised that the near-erect low-resistivity anomalies in the east might be a fragmentation zone,while the low resistance anomalies in the west,which are inclined to the westward,might be a tectonic structure or fragmentation zone related to the regional major fault,and the results of the tunnelling confirmed the reliability of the inversion interpretation.The 3D inversion can fully reflect the development scale and morphological changes of the fracture zone,and the inversion model is more reliable.Finally,it is concluded that the audio magnetotelluric method,which adopts advanced acquisition,processing and inversion interpretation techniques,is an effective means of over-detection of tunnels.展开更多
基金funded by the Natural Science Foundation of Chongqing(CSTB2023NSCQMSX0279)the Science and Technology Research Program of Chongqing Municipal Education Commission(KJQN202201119).
文摘To accelerate the large-scale integration of renewable energy and support the strategic goals of“carbon peaking and carbon neutrality,”High Voltage Direct Current(HVDC)transmission technology has made significant breakthroughs.Among the various approaches,a hybrid DC transmission system that combines a line-commutated converter(LCC)and a voltage source converter(VSC)retains the inherent fault self-clearing capability of the LCC topology while mitigating the risk of commutation failure when connected to a weak grid.In this paper,based on the harmonic generation mechanisms of hybrid DC transmission systems,an improved 3-pulse harmonic source model of the LCC and a dynamic phase-sequence harmonic analysis model of the VSC are developed.The integrated harmonic model demonstrates strong adaptability in accurately calculating DC-side harmonics under the influence of power imbalances and background harmonics.Based on this model,the fundamental characteristics of DC-side harmonics in hybrid DC transmission systems are analyzed.To mitigate harmonic effects,this paper proposes an LCLC-trap2 high-order filter structure with parallel RC damping circuits and a co-optimized design of filter parameters.Finally,a±500 kV hybrid DC transmission systemismodeled using theMATLAB/Simulink platform,and the harmonic filtering performances of the conventional LC filter,the Butterworth filter,and the proposed filter are simulated and compared.The results verify that the proposed filter offers superior performance in suppressing low-order harmonics under nonideal operating conditions.
文摘[Introduction] Accurate calculation of the hydrodynamic coefficients for floating structures and the investigation of the flow field distribution around floating bodies on the marine free surface are essential for improving the engineering design and application of marine structures.[Method] This study utilized the computational fluid dynamics(CFD) approach and the Reynolds Averaged NavierStokes(RANS) method and considered the effects of viscosity and free surface interactions on the hydrodynamic behavior of floating structures.By employing the dynamic mesh technique,this study simulated the periodic movements of simplified three-dimensional(3D)shapes:spheres,cylinders,and cubes,which were representative of complex marine structures.The volume of fluid(VOF) method was leveraged to accurately track the nonlinear behavior of the free surface.In this analysis,the added mass and damping coefficients for the fundamental modes of motion(surge,heave,and roll) were calculated across a spectrum of frequencies,facilitating the fast determination of hydrodynamic forces and moments exerted on floating structures.[Result] The results of this study are not only consistent with the results of the 3D potential flow theory but also further reflect the role of viscosity.This method can be used for precise calculation of the hydrodynamic coefficients of floating structures and for describing the flow field of such structures in motion on a free surface.[Conclusion] The methodology presented goes beyond the traditional potential flow approach.
文摘To overcome the limitations of structural height imposed by airspace restrictions in the design of maintenance hangar roofs with long spans,a new diagonal truss roof structural system is introduced for the first time.In the design of China Southern Airlines No.1 Hangar,4 main trusses were arranged diagonally along the depth direction,forming a W-shape truss.3 lineshaped trusses were arranged along the span direction,and double-layer space latticed structure is laid on them.The design optimized the height of the 183 m+222 m super long-span roof to 11.5 m,the maximum dimension the site could provide,so that the building height is within the permitted 40m.The steel consumption of the roof is only 165 kg/m^(2).The installation of diagonal trusses changed the unidirectional load transmission path of the roof and enhanced the spatial load transmission,effectively relieving the burden on the gate-side truss.This design enables the implementation of a maintenance hangar with a 222 m-span and heavy roof within the constraints of low airspace height.
基金Beijing Nova Program under Grant No.2022036National Key Research and Development Program under Grant No.2019YFC1521000。
文摘To quantify the seismic effectiveness of the most commonly used fishing line tie up method for securing museum collections and optimize fixed strategies for exhibitions,shaking table tests of the seismic systems used for typical museum collection replicas have been carried out.The influence of body shape and fixed measure parameters on the seismic responses of replicas and the interaction behavior between replicas and fixed measures have been explored.Based on the results,seismic effectiveness evaluation indexes of the tie up method are proposed.Reasonable suggestions for fixed strategies are given,which provide a basis for the exhibition of delicate museum collections considering the principle of minimizing seismic responses and intervention.The analysis results show that a larger ratio of height of mass center to bottom diameter led to more intense rocking responses.Increasing the initial pretension of fishing lines was conducive to reducing the seismic responses and stress variation of the lines.Through comprehensive consideration of the interaction forces and effective securement,it is recommended to apply 20%of breaking stress as the initial pretension.For specific museum collections that cannot be effectively protected by the independent tie up method,an optimized strategy of a combination of fishing lines and fasteners is recommended.
文摘The paper establishes a multidisciplinary design and optimization framework that aims at minimizing Unmanned aerial vehicles (UAV) development costs. This framework integrates development costs as an equally important factor alongside weight and aerodynamic disciplines within the UAV design process. The OpenMDAO paradigm is employed to facilitate a standalone design and optimization application. A comprehensive multidisciplinary analysis module is developed, encompassing initial geometrical sizing, weight analysis, aerodynamic performance evaluation, and estimation models for development costs. The effectiveness of the framework is validated through a low-cost, high-performance UAV case study. The results demonstrate that neglecting the influence of UAV development costs would be imprudent. By appropriately adjusting design parameters using the optimization algorithm, significant reductions in UAV development costs can be achieved with minimal performance losses.
文摘With the rapid development of urban construction,the land around mountains has unique resource and environmental advantages,so that the land around mountains become a rare resource for development and construction.To make scientific use of land resources around mountains and avoid excessive and disorderly development of mountains,it is particularly important to protect and control mountain resources.Xuzhou City is rich in mountain forest resources.In this paper,from the perspective of urban design,the construction control of land around mountains in Xuzhou City is studied and explored,and the requirements and methods for the detailed planning and urban design of plots around important mountains are put forward from the aspects of mountain protection classification,control principles of the height of buildings around mountains,and control principles of construction and development intensity of plots around mountains.
文摘Green energy conservation is the mainstream trend in the current development of the construction industry.The application of energy-saving technology in building electrical system design can effectively reduce energy consumption,avoid unnecessary energy consumption,and truly achieve energy conservation and environmental protection.Based on this,the article elaborates on the principles of energy-saving design in building electrical systems,and actively explores the application of energy-saving technologies from different perspectives such as optimizing power supply and distribution system design,adopting high-efficiency energy-saving lighting equipment,applying renewable energy,promoting smart home technology,and improving the efficiency of building electrical equipment.
基金Project(52278421)supported by the National Natural Science Foundation of ChinaProject(2024ZZTS0754)supported by the Fundamental Research Funds for the Central Universities of Central South University,China+2 种基金Project(2023CXQD067)supported by the Central South University Innovation-Driven Research Programme,ChinaProject(2022QNRC001)supported by Young Elite Scientists Sponsorship Program by CASTProject(2023TJ-N24)supported by the Youth Talent Program by China Railway Society and the Hunan Provincial Science and Technology Promotion Talent Project。
文摘Waterproof performance of gaskets between segments is the focus of shield tunnels.This paper proposed an analytical method for determining seepage characteristics at tunnel-gasketed joints based on the hydraulic fracturing theories.First,the mathematical model was established,and the seepage governing equation and boundary conditions were obtained.Second,three dimensionless parameters were introduced for simplifying the expressions,and the seepage governing equations were normalized.Third,analytical expressions were derived for the interface opening and liquid pressure.Moreover,the influencing factors of seepage process at the gasketed interface were analyzed.Parametric analyses revealed that,in the normalized criterion of liquid viscosity,the liquid tip coordinate was influenced by the degree of negative pressure in the liquid lag region,which was related to the initial contact stress.The coordinate of the liquid tip affected the liquid pressure distribution and the interface opening,which were analyzed under different liquid tip coordinate conditions.Finally,under two limit states,comparative analysis showed that the results of the variation trend of the proposed method agree well with those of previous research.Overall,the proposed analytical method provides a novel solution for the design of the waterproof in shield tunnels.
基金National Natural Science Foundation of China under Grant No.51578463。
文摘The vibration response and noise caused by subway trains can affect the safety and comfort of superstructures.To study the dynamic response characteristics of subway stations and superstructures under train loads with a hard combination,a numerical model is developed in this study.The indoor model test verified the accuracy of the numerical model.The influence laws of different hard combinations,train operating speeds and modes were studied and evaluated accordingly.The results show that the frequency corresponding to the peak vibration acceleration level of each floor of the superstructure property is concentrated at 10–20 Hz.The vibration response decreases in the high-frequency parts and increases in the lowfrequency parts with increasing distance from the source.Furthermore,the factors,such as train operating speed,operating mode,and hard combination type,will affect the vibration of the superstructure.The vibration response under the reversible operation of the train is greater than that of the unidirectional operation.The operating speed of the train is proportional to its vibration response.The vibration amplification area appears between the middle and the top of the superstructure at a higher train speed.Its vibration acceleration level will exceed the limit value of relevant regulations,and vibration-damping measures are required.Within the scope of application,this study provides some suggestions for constructing subway stations and superstructures.
文摘[Objective]The channel straightening project of the Pinglu Canal has fragmented the river course,compromising the integrity of original river course and causing ecosystem patchiness.Understanding the current status of fish resources and the characteristics of their diversity is crucial for the ecological management of the Pinglu Canal.[Methods]During the spring and autumn in 2021 and 2022,a survey of fish resources and species diversity in the Pinglu Canal was conducted using multi-mesh gill nets.A total of 125 fish species were collected,belonging to 10 orders,34 families,and 89 genera.[Results]The result showed that the Pinglu Canal contained three nationally protected Class II species,two endemic species of the Qinjiang River,three anadromous/migratory species,and eight invasive species,accounting for 2.4%,1.6%,2.4%,and 6.4%of the total species,respectively.The fish community primarily consisted of mid-and bottom-dwelling,adhesive-egg-laying,and omnivorous species.The Shannon-Wiener,Simpson,Margalef,and Pielou indices of the fish community in the Pinglu Canal ranged from 2.347 to 2.757,0.081 to 0.151,3.493 to 4.382,and 0.812 to 0.892,respectively.These indices showed relatively uniform distribution across different river reaches.[Conclusion]The result indicate that the fish community structure in the Pinglu Canal is relatively uniform.The reach from the Yujiang River to the Shaping River shows higher stability,while other river reaches experience moderate or severe disturbances.This study provides supplementary baseline data on the fish community structure in the Pinglu Canal and explores the potential impact of inter-basin connectivity on fish resources,aiming to provide a scientific basis for habitat restoration assessments after the channel straightening project.
基金supported by the National Natural Science Foundation of China(12072347)the Excellent Training Plan of the Institute of Mechanics,Chinese Academy of SciencesCNPC New Energy Key Project(2021DJ4902).
文摘To study the development of imbibition such as the imbibition front and phase distribution in shale,the Lattice Boltzmann Method(LBM)is used to study the imbibition processes in the pore-throat network of shale.Through dimensional analysis,four dimensionless parameters affecting the imbibition process were determined.A color gradient model of LBM was used in computation based on a real core pore size distribution.The numerical results show that the four factors have great effects on imbibition.The impact of each factor is not monotonous.The imbibition process is the comprehensive effect of all aspects.The imbibition front becomes more and more non-uniform with time in a heterogeneous pore-throat network.Some non-wetting phases(oil here)cannot be displaced out.The displacement efficiency and velocity do not change monotonously with any factor.The development of the average imbibition length with time is not smooth and not linear in a heterogeneous pore-throat network.Two fitting relations between the four dimensionless parameters and the imbibition velocity and efficiency are obtained,respectively.
文摘[Objective]Implementation of the Ten-Year Fishing Ban policy may alter fish diversity and niche characteristics of dominant species in spawning grounds within the National Nature Reserve for Rare and Endemic Fish in the Upper Yangtze River.This study initiated continuous monitoring of natural spawning habitats from February 2022 to assess these ecological changes.[Methods]Environmental DNA(eDNA)metabarcoding was employed to analyze fish species composition,biodiversity patterns,and niche parameters of dominant species.Water sampling followed the CEN/TS 19461 standard across five monitoring transects(ZT1-ZT5).[Results]The eDNA analysis detected 45 species of fish belonging to 38 genera,13 families,and 3 orders were detected through environmental DNA(eDNA)in this survey,including 10 species endemic to the upper reaches of the Yangtze River,such as Procypris rabaudi and Myxocyprinus asiaticus.The fish community was mainly composed of bottom-dwelling,settling ovum-producing,omnivorous fish.The variation ranges of the Chao1 index,ACE index,Shannon index,and Simpson index are 736~996,719~965,1.58~3.23,and 0.83~0.99,respectively,indicating that fish species in spawning sites are abundant and community distribution uniformity is high.All indexes are highest at ZT1 monitoring points.Cluster analysis showed that,at a certain similarity level,fish community types in spawning sites could be basically divided into two groups:ZT1,ZT3,and ZT5 clustered together,and ZT2 and ZT4 clustered together,indicating similar fish community habitats.There are 9 dominant fish species in typical deep pool habitats in the reserve,with niche widths(Bi)ranging from 1.13 to 3.87.The dominant fish species are broad and medium niche fish,such as Cyprinus carpio and Hemiculter tchangi,with the niche overlap index(Oik)of some dominant fish species reaching more than 0.95.This indicates fierce competition for resources among the fish in this spawning ground.[Conclusion]The Zhutuo spawning ground demonstrates high species richness with homogeneous community structure and intense resource competition.This study establishes an eDNA-based monitoring framework that enhances conventional survey method,providing critical baseline data for adaptive management under the fishing moratorium regime.
基金supported by Gansu Provincial Science and Technology Plan(23CXGA0195)Longnan Science and Technology Plan(2024CX03)。
文摘Graphene oxide nanomaterials are increasingly used in various fields due to their superior properties.In order to study the influence of graphene oxide additives on the performance of modified asphalt,in this study,graphene oxide modified asphalt was prepared and characteristics was studied including the high deformation resistance performance and the self-healing property of modified asphalt.Functional groups and morphology of graphene oxide modified asphalt were described by Fourier transform infrared spectroscopy.The high deformation resistance performance and self-healing effect of asphalt samples were obtained through dynamic slear rheometer(DSR)test.Results shows that graphene oxide dispersions improve the performance of asphalt relatively well compared to graphene oxide powder.There is no chemical reaction between graphene oxide and asphalt,but physical connection.The addition of graphene oxide improved the high deformation resistance of modified asphalt and expedited the self-healing ability of asphalt under fatigue load.
基金National Key R&D Program of China(2022YFB2602900)R&D Fund Project of China Academy of Railway Sciences Corporation Limited(2021YJ084)+2 种基金Project of Science and Technology R&D Program of China Railway(2016G002-K)R&D Fund Project of China Railway Major Bridge Reconnaissance&Design Institute Co.,Ltd.(2021)R&D Fund Project of China Railway Shanghai Group(2021141).
文摘Purpose–The bridge expansion joint(BEJ)is a key device for accommodating spatial displacement at the beam end,and for providing vertical support for running trains passing over the gap between the main bridge and the approach bridge.For long-span railway bridges,it must also be coordinated with rail expansion joint(REJ),which is necessary to accommodate the expansion and contraction of,and reducing longitudinal stress in,the rails.The main aim of this study is to present analysis of recent developments in the research and application of BEJs in high-speed railway(HSR)long-span bridges in China,and to propose a performance-based integral design method for BEJs used with REJs,from both theoretical and engineering perspectives.Design/methodology/approach–The study first presents a summary on the application and maintenance of BEJs in HSR long-span bridges in China representing an overview of their state of development.Results of a survey of typical BEJ faults were analyzed,and field testing was conducted on a railway cable-stayed bridge in order to obtain information on the major mechanical characteristics of its BEJ under train load.Based on the above,a performance-based integral design method for BEJs with maximum expansion range 1600 mm(±800 mm),was proposed,covering all stages from overall conceptual design to consideration of detailed structural design issues.The performance of the novel BEJ design thus derived was then verified via theoretical analysis under different scenarios,full-scale model testing,and field testing and commissioning.Findings–Two major types of BEJs,deck-type and through-type,are used in HSR long-span bridges in China.Typical BEJ faults were found to mainly include skewness of steel sleepers at the bridge gap,abnormally large longitudinal frictional resistance,and flexural deformation of the scissor mechanisms.These faults influence BEJ functioning,and thus adversely affect track quality and train running performance at the beam end.Due to their simple and integral structure,deck-type BEJs with expansion range 1200 mm(±600 mm)or less have been favored as a solution offering improved operational conditions,and have emerged as a standard design.However,when the expansion range exceeds the above-mentioned value,special design work becomes necessary.Therefore,based on engineering practice,a performance-based integral design method for BEJs used with REJs was proposed,taking into account four major categories of performance requirements,i.e.,mechanical characteristics,train running quality,durability and insulation performance.Overall BEJ design must mainly consider component strength and the overall stiffness of BEJ;the latter factor in particular has a decisive influence on train running performance at the beam end.Detailed BEJ structural design must stress minimization of the frictional resistance of its sliding surface.The static and dynamic performance of the newlydesigned BEJ with expansion range 1600 mm have been confirmed to be satisfactory,via numerical simulation,full-scale model testing,and field testing and commissioning.Originality/value–This research provides a broad overview of the status of BEJs with large expansion range in HSR long-span bridges in China,along with novel insights into their design.
文摘A group optimal penetration strategy in complex attack and defense confrontation situation is proposed in this paper to solve the coordinated penetration decision-making problem of endo-atmospheric gliding simultaneous multi-missile penetration of interceptors.First,the problem of large search space of multi-missile coordinated penetration maneuvers is fully considered,and the flight corridor of multi-missile coordinated penetration is designed to constrain search space of multi-agent coordinated strategy,comprehensively considering path constraints and anticollision constraints of gliding multi-missile flight.Then,a multi-missile hierarchical coordinated decision-making mechanism based on confrontation situation is proposed,and the swarm penetration strategy is optimized with the goal of maximizing swarm penetration effectiveness.The upper layer plans the swarm penetration formation according to confrontation situation,and generates the swarm coordinated penetration trajectory based on Multi-Agent Deep Deterministic Policy Gradient(MADDPG)method.The lower layer interpolates and smooths penetration trajectory,and generates the penetration guidance command based on Soft Actor-Critic and Extended Proportional Guidance(SAC-EPG)method.Simulation results verify that the proposed multi-missile cooperative penetration method based on hierarchical reinforcement learning converges faster than the penetration method based on MADDPG,and can quickly learn multi-missile cooperative penetration skills.In addition,multi-missile coordination can give full play to the group's detection and maneuverability,and occupy favorable penetration time and space through coordinated ballistic maneuvers.Thus the success rate of group penetration can be improved.
基金financially supported by the National Natural Science Foundation of China(Grant No.42102303)the Natural Science Foundation of Yunnan Province,China(Grant No.202401CF070174)the Xingdian Talent Support Program(Grant No.C619300A130).
文摘Cyclic wetting-drying alternation has a significant influence on the strength and structure of soils.It is prone to causing soil softening and disintegration,highlighting the importance to improve the soil's resistance to disintegration.This paper utilizes a self-developed disintegration test apparatus to analyze the disintegration characteristics of improved red soil under wet-dry cycles,focusing on the disintegration amount and ratio.Furthermore,XRD(X-ray diffraction),SEM(scanning electron microscope),tensile test,and contact angle test are employed to investigate the anti-disintegration behaviors of the improved red soil.The results show that the disintegrating amount and ratio of undisturbed and improved red soil are distinctly different under wet-dry cycles.Linear,stepped,constant and concave but perfect"S"shapes of the disintegrating ratio are observed in the cyclic tests.Cement and lime strengthen the red soil primarily through hydration reaction.The drop experiment confirms that cement plays a crucial role in restraining the disintegration.When the ameliorant content is low,the correlation between pore parameters and disintegration duration of red soil follows the order:mean shape coefficient>fractal dimension>probability entropy>area probability distribution index.With a high ameliorant content,the correlation remains similar,with slightly higher correlation for probability entropy.Under wet-dry cycle conditions,sludge and kaolin can improve the soil through the bonding of clay particles.The improved water repellency greatly enhances the resistance to disintegration of the altered red soil.The research provides valuable insights for the practical application of soil.
文摘An intelligent endo-atmospheric penetration strategy based on generative adversarialreinforcement learning is proposed in this manuscript.Firstly,attack and defense adversarial mod-els are established,and missile maneuver penetration problem is transformed into an optimal con-trol problem,considering penetration,handover position and mid-terminal guidance velocityconstraints.Then,Radau Pseudospectral method is adopted to generate data samples consideringrandom perturbations.Furthermore,Generative Adversarial Imitation Learning Combined withDeep Deterministic Policy Gradient method(GAIL-DDPG)is designed,with internal processreward signals constructed to tackle long-term sparse reward in missile manuver penetration prob-lem.Finally,penetration strategy is trained and verified.Simulation shows that using generativeadversarial reinforcement learning,with sample library to learn expert experience in training earlystage,the proposed method can quickly converge.Also,performance is further optimized with rein-forcement learning exploration strategy in the later stage of training.Simulation shows that the pro-posed method has better engineering application ability compared with traditional reinforcementlearning method.
基金supported by grants from 2020 Guangdong Provincial and Municipal Joint Fund For Basic and Applied Basic Research Project(2020B1515120031)2020 Foshan Municipal Deng Fang Distinguished Research Program(2020A007)+2 种基金Key Scientific Research Program for the development of Ex vivo Liver Perfusion System of Foshan City,China[(2019)No.42]Science and Technol-ogy Program of Guangzhou(202002030201)Guangzhou Sci-ence and Technology Plan(2025A04J3674)。
文摘Background:The use of grafts from donation after circulatory death(DCD)overcomes the inadequate donor organ supply.Our team developed a transportable dual hypothermic oxygenated machine perfusion(DHOPE)device,which initiates DHOPE at a recipient center to reduce static cold storage(SCS)time and the risk of graft failure in DCD liver transplantation.Methods:Six porcine livers per group with 30 min of warm ischemia exposure were preserved via SCS or DHOPE for 6 h and then reperfused for 12 h with whole blood to mimic transplantation.Hepatocellular and biliary function and injury were assessed in perfusate and bile samples.Molecular biomarkers and histology were compared between groups.Results:Reperfusion portal vein pressure,in a flow-constant manner,and alanine aminotransferase(ALT),aspartate aminotransferase(AST),alkaline phosphatase(ALP)and gamma-glutamyltransferase(γ-GGT)release were significantly lower in the DHOPE group than in the SCS group at all time points.Higher bile production paralleled the lower levels of ALP andγ-GGT in the DHOPE group.The DHOPE group secreted more total bilirubin(TBIL)in bile,resulting in decreased TBIL in the perfusate,and livers preserved with DHOPE exhibited better cholangiocellular function.Furthermore,improvements in hypoxia,the inflammatory response,cell-free microRNAs and energy metabolism were observed in the DHOPE group.There were fewer apoptotic cells and TGF-β1-positive cells in the liver parenchyma and extrahepatic bile duct in the DHOPE group than in the SCS group.Conclusions:This study demonstrates the efficacy of local 4℃DHOPE to protect porcine liver grafts from30-min warm ischemia damage.
文摘In recent years,decomposition-based evolutionary algorithms have become popular algorithms for solving multi-objective problems in real-life scenarios.In these algorithms,the reference vectors of the Penalty-Based boundary intersection(PBI)are distributed parallelly while those based on the normal boundary intersection(NBI)are distributed radially in a conical shape in the objective space.To improve the problem-solving effectiveness of multi-objective optimization algorithms in engineering applications,this paper addresses the improvement of the Collaborative Decomposition(CoD)method,a multi-objective decomposition technique that integrates PBI and NBI,and combines it with the Elephant Clan Optimization Algorithm,introducing the Collaborative Decomposition Multi-objective Improved Elephant Clan Optimization Algorithm(CoDMOIECO).Specifically,a novel subpopulation construction method with adaptive changes following the number of iterations and a novel individual merit ranking based onNBI and angle are proposed.,enabling the creation of subpopulations closely linked to weight vectors and the identification of diverse individuals within them.Additionally,new update strategies for the clan leader,male elephants,and juvenile elephants are introduced to boost individual exploitation capabilities and further enhance the algorithm’s convergence.Finally,a new CoD-based environmental selection method is proposed,introducing adaptive dynamically adjusted angle coefficients and individual angles on corresponding weight vectors,significantly improving both the convergence and distribution of the algorithm.Experimental comparisons on the ZDT,DTLZ,and WFG function sets with four benchmark multi-objective algorithms—MOEA/D,CAMOEA,VaEA,and MOEA/D-UR—demonstrate that CoDMOIECO achieves superior performance in both convergence and distribution.
基金projects of China Railway Beijing Group Company Limited.(No.2016CG23)for funding this research。
文摘The geological disasters such as collapse,mud bursting and water gushing often occur during tunnel construction.Thus,it is of great significance to detect the hidden geological disasters ahead of the tunnel face.The audio magnetotelluric(AMT)was applied for the advanced detectionstudy during the boring process of the Tianheshan tunnel in the Taihang Mountains.Three AMT profiles were deployed above the tunnel,and the data obtained in the field were analysed in terms of electrical principal axes.From shallow to deep,the direction of the geoelectric strike angle changes,generally between 30°and 60°NE,which is consistent with similar to the direction of the Taihangshan Uplift,and the data show some 3D characteristics.Two-dimensional(2D)and three-dimensional(3D)inversion methods were adopted to jointly study the subsurface structural information,and the resistivity model was geophysically and geologically interpreted.Two sets of low resistance anomalies were found,and it was hypothesised that the near-erect low-resistivity anomalies in the east might be a fragmentation zone,while the low resistance anomalies in the west,which are inclined to the westward,might be a tectonic structure or fragmentation zone related to the regional major fault,and the results of the tunnelling confirmed the reliability of the inversion interpretation.The 3D inversion can fully reflect the development scale and morphological changes of the fracture zone,and the inversion model is more reliable.Finally,it is concluded that the audio magnetotelluric method,which adopts advanced acquisition,processing and inversion interpretation techniques,is an effective means of over-detection of tunnels.
