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Intelligent Fault Diagnosis of Rolling Bearing With Variable Speed Based on ASTFrFT and Time-Frequency BoTNet Model 认领 引用
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作者 Jie Ma Jun Wei Xinyu Wang 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2026年第7期1761-1763,共3页
Dear Editor,This letter presents an intelligent fault diagnosis method for variable speed rolling bearings based on the adaptive short-time fractional Fourier transform(ASTFrFT)and the time-frequency BoTNet(TFB)to add... Dear Editor,This letter presents an intelligent fault diagnosis method for variable speed rolling bearings based on the adaptive short-time fractional Fourier transform(ASTFrFT)and the time-frequency BoTNet(TFB)to address the challenge of extracting fault characteristics of rolling bearings under variable speed conditions and the poor classification of classical deep learning models.Firstly,to address the limitations of FrFT in time-varying signal processing,the physical mechanism of traditional STFT is extended into the FrFT domain by minimizing fuzzy entropy values to construct the order matrix. 展开更多
关键词 variable speed rolling bearings time frequency botnet rolling bearings deep learning modelsfirstlyto variable speed adaptive short time fractional fourier transform extracting fault characteristics intelligent fault diagnosis
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OptimizationDesign and Numerical Simulation of Variable Tube Diameter Heat Exchanger for Split Air Conditioning Indoor Unit 认领 引用 被引量：1
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作者 Zheming Cheng Xinping Ou Yang +2 位作者 Leren Tao Zihao Wang Ke Sun 《Frontiers in Heat and Mass Transfer》 EI CAS 2026年第1期288-313,共26页
Energy shortage has become one of themost concerning issues in the world today,and improving energy utilization efficiency is a key area of research for experts and scholars worldwide.Small-diameter heat exchangers of... Energy shortage has become one of themost concerning issues in the world today,and improving energy utilization efficiency is a key area of research for experts and scholars worldwide.Small-diameter heat exchangers offer advantages such as reduced material usage,lower refrigerant charge,and compact structure.However,they also face challenges,including increased refrigerant pressure drop and smaller heat transfer area inside the tubes.This paper combines the advantages and disadvantages of both small and large-diameter tubes and proposes a combined-diameter heat exchanger,consisting of large and small diameters,for use in the indoor units of split-type air conditioners.There are relatively few studies in this area.In this paper,A theoretical and numerical computation method is employed to establish a theoretical-numerical calculation model,and its reliability is verified through experiments.Using this model,the optimal combined diameters and flow path design for a combined-diameter heat exchanger using R32 as the working fluid are derived.The results show that the heat transfer performance of all combined diameter configurations improves by 2.79%to 8.26%compared to the baseline design,with the coefficient of performance(COP)increasing from 4.15 to 4.27~4.5.These designs can save copper material,but at the cost of an increase in pressure drop by 66.86%to 131.84%.The scheme IIIH,using R32,is the optimal combined-diameter and flow path configuration that balances both heat transfer performance and economic cost. 展开更多
关键词 Split air condition variable tube diameter enhanced heat transfer numerical simulation structural design optimization
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GENERALIZING SUBDIFFUSIVE BLACK-SCHOLES MODEL BY VARIABLE EXPONENT:MODEL TRANSFORMATION AND NUMERICAL APPROXIMATION 认领 引用
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作者 Meihui ZHANG Yaxue LIU +2 位作者 Mengmeng LIU Wenlin QIU Xiangcheng ZHENG 《Acta Mathematica Scientia》 SCIE CSCD 2026年第2期993-1010,共18页
This work generalizes the subdiffusive Black-Scholes model by introducing the variable exponent in order to provide adequate descriptions for the option pricing,where the variable exponent may account for the variatio... This work generalizes the subdiffusive Black-Scholes model by introducing the variable exponent in order to provide adequate descriptions for the option pricing,where the variable exponent may account for the variation of the memory property.In addition to standard nonlinear-to-linear transformation,we apply a further spatial-temporal transformation to convert the model to a more tractable form in order to circumvent the difficulties caused by the"non-positive,non-monotonic"variable-exponent memory kernel.An interesting phenomenon is that the spatial transformation not only eliminates the advection term but naturally turns the original noncoercive spatial operator into a coercive one due to the specific structure of the Black-Scholes model,which thus avoids imposing constraints on coefficients.Then we perform numerical analysis for both the semi-discrete and fully discrete schemes to support numerical simulation.Numerical experiments are carried out to substantiate the theoretical results. 展开更多
关键词 Black-Scholes model subdiffusion variable exponent error estimate option pricing
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Analytical solution for longitudinal seismic response of variable stiffness tunnel with isolation layers under shear waves 认领 引用
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作者 LIU Xiang YANG Jiao-jiao +3 位作者 LI Kui-chen LU Tong JIANG An-nan FANG Qian 《Journal of Central South University》 SCIE EI CAS CSCD 2026年第6期2844-2867,共24页
Seismic isolation design typically emphasizes transverse responses of tunnels,with comparatively limited research on longitudinal isolation responses.Previous analytical solutions for isolation response are inapplicab... Seismic isolation design typically emphasizes transverse responses of tunnels,with comparatively limited research on longitudinal isolation responses.Previous analytical solutions for isolation response are inapplicable to variable stiffness tunnels.To address research gaps,analytical solutions for longitudinal seismic responses of variable stiffness tunnels with isolation layers are proposed.The solution can be applied to engineering practice.The mechanical model of isolation layers is developed using the Kelvin model.The variable stiffness tunnel is simplified as two semi-infinite beams embedded in homogeneous and isotropic soil layers.Governing equations are solved using integral transformations and continuity conditions.Analytical expressions are obtained by introducing displacement phase angles to simulate traveling wave effects.The proposed analytical solutions are validated through comparisons with results from existing literature and verified using numerical simulations.Parametric sensitivity analyses are conducted to investigate effects of tunnels with and without an isolation layer,isolation layer thickness and elastic modulus,tunnel stiffness ratio,and wavelength and amplitude of shear waves on seismic responses of variable stiffness tunnels.Changes in stiffness have a more significant effect on internal forces than displacements.Additionally,isolation layer's thickness and elastic modulus can be optimized through our method to balance structural performance and economic efficiency. 展开更多
关键词 isolation layer variable stiffness tunnel analytical solution seismic response shear waves
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Mechanical responses of super-large-span variable cross-section tunnels in weak surrounding rock:A case study and the application of a novel constitutive model 认领 引用
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作者 CAO Wenxin ZHAO Wen +5 位作者 LIU Keqi SHAO Binghua BAI Qian ZHANG Yongfeng LU Bo WANG Yantao 《Journal of Mountain Science》 SCIE CSCD 2026年第6期2835-2855,共21页
Super-large-span and variable cross-section tunnels have proliferated in urban expressway systems across China.However,the deformation behavior and load distribution mechanisms in super-large and variable cross-sectio... Super-large-span and variable cross-section tunnels have proliferated in urban expressway systems across China.However,the deformation behavior and load distribution mechanisms in super-large and variable cross-section tunnels remain inadequately understood.This study systematically analyzed the mechanical response characteristics of super-large-span and variable cross-section tunnels in weak surrounding rock based on extensive field monitoring data.Mechanical tests were conducted to reveal the strain-softening characteristics of weak surrounding rock,and the nonlinear evolution of strength parameters was summarized.Through secondary development,a novel constitutive model based on the Hoek-Brown strength criterion was proposed and successfully implemented in FLAC3D.Furthermore,numerical simulations were conducted using an improved constitutive model.These simulations investigated the evolution of deformation and internal forces within the support system,accounting for the coupled effects of multiple factors.The research shows that the rock pillar compensates for the insufficient stiffness of temporary middle diaphragms.However,it also alters the mechanical behavior of the steel frame system,which leads to significant stress concentrations at the arch shoulders.Additionally,the"asymmetrical loading effect"commonly observed at variable cross-sections substantially impacts the support system within these span transition zones. 展开更多
关键词 Weak surrounding rock Super-large-span tunnel Variable cross-sections Field monitoring Mechanical tests Secondary development
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A data-and expert-driven framework for establishing land cover-related essential variables for SDG monitoring and assessment 认领 引用
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作者 Hao Wu Ping Zhang +6 位作者 Jun Chen Songnian Li Jing Li Shu Peng Dongyang Hou Jun Zhang Hao Chen 《Geography and Sustainability》 CSCD 2026年第1期236-246,共11页
Sustained and spatially explicit monitoring of the United Nations 2030 Agenda for Sustainable Development is critical for effectively tracking progress toward the global Sustainable Development Goals(SDGs).Although la... Sustained and spatially explicit monitoring of the United Nations 2030 Agenda for Sustainable Development is critical for effectively tracking progress toward the global Sustainable Development Goals(SDGs).Although land cover information has long been recognized as an essential component for monitoring SDGs,a standardized scientific framework for identifying and prioritizing land cover related essential variables does not exist.Therefore,we propose a novel expert-and data-driven framework for identifying,refining,and selecting a priority list of Essential Land cover-related Variables for SDGs(ELcV4SDGs).This framework integrates methods including expert knowledge-based analysis,clustering of variables with similar attributes,and quantified index calculation to establish the priority list.Applying the framework to 15 specific SDG indicators,we found that the ELcV4SDGs priority list comprises three main categories,type and structure,pattern and intensity,and process and evolution of land cover,which are further divided into 19 subcategories and ultimately encompass 50 general variables.The ELcV4SDGs will support detailed spatial monitoring and enhance their scientific applications for SDG monitoring and assessment,thereby guiding future SDG priority actions and informing decision-making to advance the 2030 SDGs agenda at local,national,and global levels. 展开更多
关键词 Essential variable Land cover SDG Spatial monitoring and assessment Interactive analysis Refinement and selection
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Analysis of bilateral constrained sliding contact problems with variable friction coefficients via a cumulative frictional dissipation approach 认领 引用
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作者 Ling Tao Ling Wang +3 位作者 Ning Hu Shaowei Tong Hong Wen Qingshui Qiu 《Theoretical & Applied Mechanics Letters》 EI CAS CSCD 2026年第2期104-114,共11页
This work investigates the bidirectional relationship between contact mechanics and frictional wear behavior in bilateral constrained sliding contact.An internal state variable representing the contact surface conditi... This work investigates the bidirectional relationship between contact mechanics and frictional wear behavior in bilateral constrained sliding contact.An internal state variable representing the contact surface condition is incorporated into the Coulomb friction law to account for wear phenomena.A contact detection method has been constructed to identify the positional relationship between two elements during contact,leveraging vectorrelated features of the vertices on the contact area between the slideway and the slider.A bipotential function for rigid bilateral constraints is formulated by introducing a stability factor.Combining the potential-Coulomb contact force model,a numerical algorithm is developed for variable friction contact problems on the basis of cumulative frictional dissipation and is initially implemented for rigid body bilateral contact problems.The algorithm is subsequently applied to bilateral constraint analysis in a sliding mechanism under both constant and variable friction conditions,and the influences of the wear and contact clearance factors are studied.The numerical results demonstrate consistency with energy conservation principles and dynamic laws,validating the effectiveness of the proposed algorithm.This work extends the applicability of the bipotential function approach and provides a theoretical foundation and analytical tools for optimizing bilateral nonideal contact structures and predicting equipment service life. 展开更多
关键词 Wear Bilateral constraint Bipotential function Variable friction Frictional dissipation
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Progress in local-variable-based transition-turbulence models for subsonic and transonic boundary layers 认领 引用
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作者 Jiakuan XU Xi JIANG +3 位作者 Yutian WANG Ningjuan DONG Lei QIAO Junqiang BAI 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2026年第4期26-53,共28页
The accurate prediction of boundary layer transition represents a persistent and extensively studied challenge in fluid mechanics and aircraft aerodynamic design.It is well recognized that,due to the limitations in co... The accurate prediction of boundary layer transition represents a persistent and extensively studied challenge in fluid mechanics and aircraft aerodynamic design.It is well recognized that,due to the limitations in computational efficiency and shape complexity,high-resolution numerical simulation techniques and classical stability theory are hard to be applied in the numerical simulation and optimization of complex aircraft designs.The classical correlation-based Langtry and Menter model and laminar kinetic energy model,incorporating stability analysis results,offer efficient solution strategies under the Reynolds-averaged Navier-Stokes framework.Nonetheless,these models rely heavily on the range of available experimental data,which significantly restricts their applicability.Therefore,the Amplification Factor Transport(AFT)transition model anchored in linear stability theory foundations was derived from the findings of Coder and Maughmer and has since been adopted for transition prediction across a variety of complex geometries.This model not only incorporates the analytical foundation of linear stability theory,but also predicts the maximum envelope N value through a transport equation.It enables all non-local variables to be solved locally,ensuring compatibility with massively parallel computational fluid dynamics solvers.This paper systematically introduces the modeling concepts and key variable solution strategies of the currently prevalent transition-turbulence models based on local variables.It emphasizes the evolution of AFT transition frameworks,highlighting their progression from applications in the transition from 2D to 3D compressible boundary layer Tollmien-Schlichting waves,together with the formation of stationary crossflow vortices.In conclusion,this paper addresses the remaining challenges of the amplification factor transport transition model and explores potential directions for its future development. 展开更多
关键词 Boundary layer transition Computational fluid dynamics Linear stability theory Local variable Transition-turbulence model
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Continuous variable cross-section recycled extrusion of Ti–6Al–4V alloy: microstructure evolution, deformation mechanism and refinement mechanism 认领 引用
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作者 Ying-Ying Liu Jun-Yi Zhang +7 位作者 Fang-Lin Wu Wen-Rui Ma Ze Wu Jia-Yi Li Jiang-Bo Zhai Shi-Feng Liu Wen Wang Kuai-She Wang 《Journal of Iron and Steel Research International》 SCIE EI CSCD 2026年第2期398-411,共14页
Continuous variable cross-section recycled extrusion(CVCE)is an advanced technique of severe plastic deformation.Ti–6Al–4V alloy was deformed with different processing parameters by CVCE,and then the microstructure ... Continuous variable cross-section recycled extrusion(CVCE)is an advanced technique of severe plastic deformation.Ti–6Al–4V alloy was deformed with different processing parameters by CVCE,and then the microstructure characterization,refinement mechanism and deformation mechanism were investigated simultaneously.The results demonstrate that the average size of grain is refined from 14 to 2.78μm as Ti–6Al–4V alloy is deformed at 800℃ with a speed of 2 mm/s over 6 passes,and the microstructure is equiaxed and distributed homogeneously along the radial direction.Furthermore,in the process of CVCE,basal slip(0001)is transformed to prismatic slip(100)system and pyramidal slip(112)system,with a reduction in low angle grain boundaries from 69.6%to 61.2%.Moreover,the grain refinement mechanism of CVCE is dislocation multiplication and cross-slip migration within the grain at the initial stage of deformation,which results in the formation of substructures and micro-shear bands as well as grain refinement.In addition,the nucleation and growth of dynamic recrystallization grains are beneficial to eliminating the dislocations,subgrain boundaries and other defects in the matrix,which finally results in the grains refinement. 展开更多
关键词 Ti-6Al-4V alloy Continuous variable cross-section recycled extrusion Microstructure Deformation mechanism Refinement mechanism
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Analytical solutions on dynamic response of a thin-walled curved beam subjected to two-axle moving load with variable speed 认领 引用
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作者 Xiaoyong Lv Liupeng Li +1 位作者 Zhiwu Yu Peng Liu 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2026年第2期237-251,共15页
This paper proposes the analytical solutions involving damping effects for the dynamic response of a simply supported thin-walled curved beam under uniformly variable two-axle moving loads in four directions:vertical,... This paper proposes the analytical solutions involving damping effects for the dynamic response of a simply supported thin-walled curved beam under uniformly variable two-axle moving loads in four directions:vertical,torsional,radial,and axial.The warping stiffness and damping of the thin-walled beam were comprehensively considered in the vibration control equations.Unlike traditional one-axle load cases,this study employs a more realistic two-axle vehicle load model.Based on the modal superposition method,the control vibration equations for thin-walled curved beams in-plane and out-ofplane under variable speed moving loads were solved using a combination of the Fourier sine transform method,the Galerkin method,and the Laplace transform method.Analytical solutions for the dynamic responses were derived in integral form,facilitating direct numerical computation.The proposed computational method’s effectiveness and accuracy were validated against published research.Subsequently,the dynamic responses of the thin-walled curved beam under one-axle and two-axle moving load models were compared,and the effects of initial load velocity,load acceleration,and center angle of the curved beam on the dynamic responses were investigated through extensive parameter research.The research results provide valuable insights into the structural behavior of thin-walled curved beams under the moving loading with variable speed. 展开更多
关键词 Thin-walled curved beam Dynamic response Variable speed Two-axle moving load Analytical solution
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A Fast Algorithm for Matrix-Variable Triconvex Optimization With Application to Blind Image Deblurring 认领 引用
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作者 Songchuan Zhang Liqing Huang +1 位作者 Youshen Xia Jun Wang 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2026年第5期1184-1206,共23页
Matrix-variable triconvex optimization is a significant generalization of vector-variable triconvex or biconvex optimization and has been found to have popular applications.To reduce computation time and storage requi... Matrix-variable triconvex optimization is a significant generalization of vector-variable triconvex or biconvex optimization and has been found to have popular applications.To reduce computation time and storage requirements,this paper presents a matrix-form iterative method for quickly solving matrix-variable constrained triconvex optimization problems.The proposed method is based on a matrix-form alternating projection iteration scheme in the form of matrix state spaces,where an efficient line search strategy is adopted by exploiting the optimality conditions of the problem for a larger step length.Compared with the existing vector-form alternating projection gradient method,the proposed method reduces storage requirements and computational cost,and thus is more computationally efficient.Each sequence generated by the proposed method is guaranteed to be globally convergent to a partial optimum under mild conditions.Finally,the proposed method is effectively applied to blind image deblurring problems.Computed results show that the proposed algorithm is superior to related iterative algorithms in terms of computation time and solution quality. 展开更多
关键词 Blind image deblurring global convergence matrixform iterative method matrix variable multiconvex optimization
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Mapping the Panorama of Enterprise Digital Transformation:An LLM-Driven Variable Relational Network Perspective 认领 引用
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作者 Zhichao Ba Yujie Zhang +1 位作者 Biao Zhang Gang Li 《Journal of Data and Information Science》 CSCD 2026年第2期10-35,共26页
Purpose:While the imperative of enterprise digital transformation(EDT)has been widely acknowledged,a systematic understanding of its intricate network of antecedents and consequences remains fragmented.This study prop... Purpose:While the imperative of enterprise digital transformation(EDT)has been widely acknowledged,a systematic understanding of its intricate network of antecedents and consequences remains fragmented.This study proposes a novel knowledge representation framework that leverages large language models(LLMs)to construct a variable relational network(VRN),offering a panoramic,micro-level perspective on EDT.Design/methodology/approach:We extract five types of variable relationships from a vast corpus of academic publications on EDT to generate the VRN.Subsequently,we apply network topology analysis to uncover the temporal and regional characteristics of the VRN.Its hierarchical structure is then analyzed through K-shell decomposition.Findings:Our results show that,over the past two decades,the scale of the VRN has experienced rapid growth,driven collectively by multi-layered external factors such as the rapid advancement of digital technologies,and its internal connections have become increasingly tighter.Regional comparisons of the VRN reveal that different economies,shaped by institutional theories,exhibit distinct transformation paradigms while striving toward common goals.K-shell analysis uncovers a clear hierarchical structure,distinguishing peripheral,intermediate,and core variables,with these layers corresponding to varying degrees of strategic significance and transformation maturity.Research limitations:The study’s limitations primarily concern the accuracy of the VRN,which depends on the LLM’s extraction performance and its potential for hallucinations,which may introduce noise into the network topology.Practical implications:The VRN and its network topology structure serve as a diagnostic tool for strategic decisionmaking,enterprises and policymakers can also use these insights to design targeted support programs.Originality/value:This study contributes a data-driven,LLM-assisted framework for mapping the evolving and multidimensional landscape of enterprise digital transformation,thereby validating and extending the theoretical boundaries of EDT. 展开更多
关键词 enterprise digital transformation scientific hypothesis large language models variable relational network hierarchical structure
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Variable-Diameter Finned-Tube Heat Exchanger Optimization for R290 Split Air Conditioners 认领 引用
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作者 Zheming Cheng Xinping Ouyang +2 位作者 Leren Tao Ke Sun Zihao Wang 《Fluid Dynamics & Materials Processing》 EI 2026年第5期147-173,共27页
Balancing heat transfer performance with material cost and refrigerant charge remains a key challenge in split air conditioning systems.To address this issue,the present study proposes a finned-tube heat exchanger wit... Balancing heat transfer performance with material cost and refrigerant charge remains a key challenge in split air conditioning systems.To address this issue,the present study proposes a finned-tube heat exchanger with a variable-diameter configuration,combining 5.2 mm and 7.3 mm tubes for use with R290 refrigerant.Three hybrid arrangements are examined against a conventional baseline with uniform 7.3 mm tubes,differing in the number and spacing of the 5.2 mm tubes integrated within the heat exchanger layout,thereby enabling targeted structural and thermal optimization of the indoor unit.An integrated methodology,based on a theoretical iterative algorithm and supported by numerical simulations and experimental validation,is employed to characterize heat transfer and fluid flow under rated cooling conditions.The results show that the proposed configurations achieve substantial reductions in refrigerant charge,by up to 11.5%,and copper usage,by up to 7.78%,while simultaneously enhancing the system coefficient of performance by as much as 3.75%compared to the reference design.Configurations with a higher proportion and tighter spacing of 5.2 mm tubes yield the greatest improvement in energy efficiency,whereas those maximizing the substitution of 7.3 mm tubes with 5.2 mm tubes achieve the most pronounced reductions in material usage and refrigerant charge.Overall,the findings demonstrate that variable-diameter tube heat exchangers provide an effective strategy for optimizing the trade-off between performance,cost,and environmental impact in R290-based split air conditioning systems. 展开更多
关键词 Variable tube diameter split air conditioner(SAC) indoor unit R290 numerical simulation structural optimization
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A TimeXer-Based Numerical Forecast Correction Model Optimized by an Exogenous-Variable Attention Mechanism 认领 引用
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作者 Yongmei Zhang Tianxin Zhang Linghua Tian 《Computers, Materials & Continua》 SCIE EI 2026年第3期1770-1785,共16页
Marine forecasting is critical for navigation safety and disaster prevention.However,traditional ocean numerical forecasting models are often limited by substantial errors and inadequate capture of temporal-spatial fe... Marine forecasting is critical for navigation safety and disaster prevention.However,traditional ocean numerical forecasting models are often limited by substantial errors and inadequate capture of temporal-spatial features.To address the limitations,the paper proposes a TimeXer-based numerical forecast correction model optimized by an exogenous-variable attention mechanism.The model treats target forecast values as internal variables,and incorporates historical temporal-spatial data and seven-day numerical forecast results from traditional models as external variables based on the embedding strategy of TimeXer.Using a self-attention structure,the model captures correlations between exogenous variables and target sequences,explores intrinsic multi-dimensional relationships,and subsequently corrects endogenous variables with the mined exogenous features.The model’s performance is evaluated using metrics including MSE(Mean Squared Error),MAE(Mean Absolute Error),RMSE(Root Mean Square Error),MAPE(Mean Absolute Percentage Error),MSPE(Mean Square Percentage Error),and computational time,with TimeXer and PatchTST models serving as benchmarks.Experiment results show that the proposed model achieves lower errors and higher correction accuracy for both one-day and seven-day forecasts. 展开更多
关键词 TimeXer model exogenous variable attention mechanism sea surface temperature temporal-spatial features forecast correction
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NONLINEAR RIEMANN AND HILBERT BOUNDARY VALUE PROBLEMS WITH SQUARE ROOTS IN VARIABLE EXPONENT SPACES 认领 引用
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作者 Yajun Hu Fuli He 《Acta Mathematica Scientia》 SCIE CSCD 2026年第1期1-18,共18页
In this paper,we study the nonlinear Riemann boundary value problem with square roots that is represented by a Cauchy-type integral with kernel density in variable exponent Lebesgue spaces.We discuss the odd-order zer... In this paper,we study the nonlinear Riemann boundary value problem with square roots that is represented by a Cauchy-type integral with kernel density in variable exponent Lebesgue spaces.We discuss the odd-order zero-points distribution of the solutions and separate the single valued analytic branch of the solutions with square roots,then convert the problem to a Riemann boundary value problem in variable exponent Lebesgue spaces and discuss the singularity of solutions at individual zeros belonging to curve.We consider two types of cases those where the coefficient is Hölder and those where it is piecewise Hölder.Then we solve the Hilbert boundary value problem with square roots in variable exponent Lebesgue spaces.By discussing the distribution of the odd-order zero-points for solutions and the method of symmetric extension,we convert the Hilbert problem to a Riemann boundary value problem.The equivalence of the transformation is discussed.Finally,we get the solvable conditions and the direct expressions of the solutions in variable exponent Lebesgue spaces. 展开更多
关键词 boundary value problem Cauchy-type integral variable exponent spaces non-linearity piecewise Lyapunov curve
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Efficient Electrical Discharge Machining of Titanium Alloy by Multiple Variable Adaptive Control System 认领 引用
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作者 Xin Mu Ming Zhou Jun Zhang 《Journal of Harbin Institute of Technology(New Series)》 CAS 2026年第2期31-43,共13页
In electrical discharge machining of titanium alloys,the1400-1600℃melting points of titanium alloysr equire the input of sufficient discharge energy to melt and vaporize the titanium alloy.However,because of low ther... In electrical discharge machining of titanium alloys,the1400-1600℃melting points of titanium alloysr equire the input of sufficient discharge energy to melt and vaporize the titanium alloy.However,because of low thermo-c onduction,the input energy can easily raise the temperature of the gap liquid to a high enough level.Usually,thee levated temperature of the gap liquid resulted in a reduction of the gap breakdown strength,so that the liquid dielectricd eionization after pulse discharging tends to be incomplete and causes occurrences of large arcing pulses,burning thew orkpiece surface and causing electrode wear.This contradiction hinders the machining of titanium alloy by Electrical Discharge Machining(EDM).To solve this issue,this study thoroughly analyzed the factors influencing gap liquidb reakdown strength during EDM and identified two key elements:gap distance and amount of chips left in gap.Based ont his analysis,a solution was proposed,which involved the development of a multiple variable adaptive control system.T his system adjusted the gap servo voltage in proportion to the gap distance to control the discharge types of pulses,r egulated the electrode discharge time to the quantity of chips left in the gap in an electrode discharge time.By dynamically adjusting these two variables,the system maintained an optimal liquid breakdown strength,facilitatinge ffective machining while preventing arcing in machining.Experimental validation confirmed that this multiple variable control system significantly enhanced the EDM process for titanium alloys,even under challenging conditions,d emonstrating its practical utility. 展开更多
关键词 electrical discharge machining adaptive control titanium alloy multiple variable control
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A Dual-Component Elastic Adaptation Network for Rotating Machinery Incremental Fault Diagnosis under Variable Operating Conditions 认领 引用
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作者 Yan Zhang Changqing Shen +3 位作者 Xiaofen Ye Liang Chen Juanjuan Shi Zhongkui Zhu 《Journal of Dynamics, Monitoring and Diagnostics》 2026年第1期49-63,共15页
In practical industrial environments,the data distribution of rotating machinery drifts as operating conditions vary,causing a marked deterioration in the performance of traditional fault diagnosis methods that rely o... In practical industrial environments,the data distribution of rotating machinery drifts as operating conditions vary,causing a marked deterioration in the performance of traditional fault diagnosis methods that rely on the assumption of identical distributions.Incremental learning provides a promising pathway to address dynamic operating conditions.However,existing approaches typically depend on replaying historical data and still struggle to strike a balance between stability and plasticity.To overcome these limitations,this paper proposes a dual-component elastic adaptive network(DCEAN)designed for incremental fault diagnosis of rotating machinery under varying working conditions.The proposed framework operates without access to previous data and simultaneously achieves knowledge retention and feature correction.Specifically,a sensitive parameter constraint(SPC)mechanism is introduced to curb excessive updates to parameters identified as critical,thereby stabilizing previously learned knowledge.In parallel,a feature drift self-calibration(FDSC)mechanism is employed to estimate and compensate for distribution shifts induced by condition variations,promoting consistency of feature representations across domains.Through the coordinated action of these two mechanisms,DCEAN establishes an incremental learning paradigm that harmonizes stability with adaptability.Two case studies demonstrate that the proposed method delivers superior diagnostic performance in variable operating environments,underscoring its robustness and effectiveness. 展开更多
关键词 feature drift incremental learning intelligent fault diagnosis rotating machinery variable operating conditions
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Latent Space Iterative Weather Prediction:an Efficient Framework for Leveraging Rich Contextual Atmospheric Variables 认领 引用
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作者 LI Shuangliang LI Siwei 《Journal of Geodesy and Geoinformation Science》 CSCD 2026年第1期11-49,共39页
Weather forecasting,which involves predicting a few critical atmospheric variables,is of significant importance to both scientific research and societal applications.Recently,deep learning methods have been introduced... Weather forecasting,which involves predicting a few critical atmospheric variables,is of significant importance to both scientific research and societal applications.Recently,deep learning methods have been introduced into this field due to their substantially reduced inference time and promising forecast accuracy.However,to comprehensively simulate atmospheric state evolution and improve the prediction accuracy of critical variables,most current approaches incorporate hundreds of auxiliary variables and iteratively predict all physical variables regardless of their relevance to critical variables,significantly increasing task complexity.Moreover,iterative forecasting of physical variables is susceptible to disturbances such as noise and missing values.To address these limitations,we propose a forecasting model to iteratively predict only the critical-variables-relevant atmospheric latent features rather than all physical variables,which achieves faster convergence and higher accuracy.These latent features are encoded and extracted from numerous variables,and they are guided by the prediction loss function to be relevant to critical atmospheric variables.Additionally,iteratively predicting latent features minimizes the impact of noise and missing values,as these are filtered out by the encoder,leading to more accurate and stable predictions.To balance performance and efficiency,we determine the optimal dimensionality of the latent features through theoretical analysis and ablation studies.Comprehensive experimental results on two ERA5 sub-datasets have demonstrated the effectiveness and efficiency of the proposed framework in improving forecasting accuracy. 展开更多
关键词 weather forecasting contextual atmospheric variables latent space iterative prediction
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Impact of environmental variables on hydrate formation kinetics in porous media systems and their contribution to CO2 capture and storage 认领 引用
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作者 Jiang Bian Hu-cheng Bai +2 位作者 Xue-wen Cao Hong-chao Wang Bo Yu 《China Geology》 CAS CSCD 2026年第3期611-623,共13页
Global dependence on fossil fuels has led to escalating atmospheric carbon dioxide emissions.The consecutive greenhouse effect poses a serious threat to the human habitat,rendering carbon dioxide abatement a key focus... Global dependence on fossil fuels has led to escalating atmospheric carbon dioxide emissions.The consecutive greenhouse effect poses a serious threat to the human habitat,rendering carbon dioxide abatement a key focus in contemporary research.Hydrate-based CO2 sequestration offers a promising pathway for carbon capture and storage,though its efficiency is strongly influenced by pressure,salinity,and sediment properties.In this study,the kinetic characteristics and occurrence states of CO2 hydrates in porous media were systematically investigated under varying pressures(3.0-3.6 MPa),NaCl concentrations(0-3.5%),and sediment types(quartz sand vs kaolinite).Results reveal a non-linear pressure dependence—gas storage capacity increases by 16.3%as pressure rises from 3.0 MPa to 3.3 MPa,but diminishes to 9.4%with further increase to 3.6 MPa.NaCl exhibits dual inhibitory effects:Thermodynamically shifting the phase equilibrium leftward in the P-T domain and kinetically suppressing growth,with 3.5%NaCl systems exhibiting persistently slow hydrate formation.Sediment type also plays a critical role,as kaolinite's low-permeability clay structure substantially impedes hydrate formation compared to quartz sand while altering hydrate distribution patterns.Understanding the interplay between pressure-driven efficiency gains and inhibitor-mediated stability control across diverse geological environments is essential for optimizing hydrate-based CO2 storage strategies. 展开更多
关键词 CO2hydrate Combustible ice Carbon storage Hydrate-bearing formatiom Carbon neutrality Porous media Experimental research Environmental variables Sediment types(quartz+kaolinite) Carbon capture,utilization,and storage(CCUS)
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Error Estimates of the BDF2 Scheme with Variable Time Steps for the Cahn-Hilliard-Magnetohydrodynamics Equations 认领 引用
20
作者 GAO Rongrong WANG Danxia 《应用数学》 北大核心 2026年第3期686-710,共25页
In this work,we investigate numerical approximation of the incompressible Cahn-Hilliard-Magnetohydrodynamics(CHMHD)system.Firstly a semi-discrete variabletime-step BDF2 numerical scheme is proposed based on two scalar... In this work,we investigate numerical approximation of the incompressible Cahn-Hilliard-Magnetohydrodynamics(CHMHD)system.Firstly a semi-discrete variabletime-step BDF2 numerical scheme is proposed based on two scalar auxiliary variables,one is used for linearizing the phase field function and the other is used for dealing with the nonlinear terms.This approach effectively reduces the computational complexity.Secondly,mass conservation,and stability of the scheme are proved.Furthermore,we break through the traditional fixed time-step approach in the temporal direction by adopting a variable-time-step method and provide error estimates for the second-order scheme through rigorous analysis.Finally,some results of numerical simulations are presented to verify the previous analysis.Additionally,an adaptive time step strategy is devised to optimize computational efficiency while ensuring accuracy. 展开更多
关键词 CHMHD equation Scalar auxiliary variable Variable-time-step BDF2 Error estimate
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