This study employed the Box-Behnken design in response surface methodology(RSM)to optimize predistillation and pressurized distillation column parameters in methanol distillation.Statistical and fittinganalyses demons...This study employed the Box-Behnken design in response surface methodology(RSM)to optimize predistillation and pressurized distillation column parameters in methanol distillation.Statistical and fittinganalyses demonstrated the effects of operational parameters and their interactions on product purity and operating costs.Results showed that for methanol mass fraction in the product,the top distillate of the predistillation column(D_(1)),the interaction between D_(1) and the top distillate of the pressurized distillation column(D_(2)),and the interaction between the theoretical plates of the pressurized distillation column(N_(2))and its refluxratio(R_(2))significantlyaffected the outcome,in addition to pressurized distillation column parameters.Acetone mass fraction was mainly influencedby predistillation column parameters and their interactions,with minimal relation to the pressurized distillation column.Operating costs were primarily affected by the refluxratio(R),withdrawal(D)of both columns,and their interactions.Optimization strategies involved increasing theoretical plates and reducing refluxratios compared to the initial plan,achieving energy-saving and consumption-reduction goals.The process required the pressurized distillation column‘s methanol mass fraction to exceed 99.80%,acetone mass fraction below 2×10^(-8),and formaldehyde mass fraction below 5×10^(-9),with a feed rate of 6100 kg·h^(-1).Plans A,B,and C achieved energy-savings of 29.80%,21.78%,and 25.50%respectively,while ensuring separation efficiencyand product quality.This research provides theoretical and practical guidance for optimizing the methanol distillation process,helping to reduce energy consumption and production costs,thereby enhancing corporate competitiveness.展开更多
Fluxgate current sensors(FGCSs)are increasingly employed in power systems due to their high-precision characteristics,yet their measurement flexibility remains constrained by conventional closed-core designs.To addres...Fluxgate current sensors(FGCSs)are increasingly employed in power systems due to their high-precision characteristics,yet their measurement flexibility remains constrained by conventional closed-core designs.To address this limitation,we proposed a split-core sensor structure comprising four magnetic core strips,which achieved non-intrusive current measurement while maintaining detection accuracy.An analytical model of the induced electromotive force was established based on the probe’s geometric configuration,followed by finite element simulations to optimize key parameters including core radius,core width,excitation coil turns,and sensing coil configuration.A complete prototype integrating the measurement probe,excitation circuit,and signal processing circuitry was developed and experimentally validated.The experimental results show a sensitivity of 0.1099 V/A,a hysteresis error of 0.559%,and a repeatability error of 1.574%over a measurement range of±10 A.After polynomial fitting-based error compensation,the nonlinearity error was reduced to 0.208%,achieving performance comparable to closed-core sensors.This work provided a practical solution for applications demanding both high measurement accuracy and installation flexibility.展开更多
To investigate the influence of different longitudinal constraint systems on the longitudinal displacement at the girder ends of a three-tower suspension bridge,this study takes the Cangrong Xunjiang Bridge as an engi...To investigate the influence of different longitudinal constraint systems on the longitudinal displacement at the girder ends of a three-tower suspension bridge,this study takes the Cangrong Xunjiang Bridge as an engineering case for finite element analysis.This bridge employs an unprecedented tower-girder constraintmethod,with all vertical supports placed at the transition piers at both ends.This paper aims to study the characteristics of longitudinal displacement control at the girder ends under this novel structure,relying on finite element(FE)analysis.Initially,based on the Weigh In Motion(WIM)data,a random vehicle load model is generated and applied to the finite elementmodel.Several longitudinal constraint systems are proposed,and their effects on the structural response of the bridge are compared.The most reasonable system,balancing girder-end displacement and transitional pier stress,is selected.Subsequently,the study examines the impact of different viscous damper parameters on key structural response indicators,including cumulative longitudinal displacement at the girder ends,maximum longitudinal displacement at the girder ends,cumulative longitudinal displacement at the pier tops,maximum longitudinal displacement at the pier tops,longitudinal acceleration at the pier tops,and maximum bending moment at the pier bottoms.Finally,the coefficient of variation(CV)-TOPSIS method is used to optimize the viscous damper parameters for multiple objectives.The results show that adding viscous dampers at the side towers,in addition to the existing longitudinal limit bearings at the central tower,can most effectively reduce the response of structural indicators.The changes in these indicators are not entirely consistent with variations in damping coefficient and velocity exponent.The damper parameters significantly influence cumulative longitudinal displacement at the girder ends,cumulative longitudinal displacement at the pier tops,and maximum bending moments at the pier bottoms.The optimal damper parameters are found to be a damping coefficient of 5000 kN/(m/s)0.2 and a velocity exponent of 0.2.展开更多
Specialized vanadium(V)-iron(Fe)-based alloy additives utilized in the production of V-containing steels were investigated.Vanadium slag from the Panzhihua region of China was utilized as a raw material to optimize pr...Specialized vanadium(V)-iron(Fe)-based alloy additives utilized in the production of V-containing steels were investigated.Vanadium slag from the Panzhihua region of China was utilized as a raw material to optimize process parameters for the preparation of V-Fe-based alloy via silicon thermal reduction.Experiments were conducted to investigate the effects of reduction temperature,holding time,and slag composition on alloy-slag separation,alloy microstructure,and the oxide content of residual slag,with an emphasis on the recovery of valuable metal elements.The results indicated that the optimal process conditions for silicon thermal reduction were achieved at reduction temperature of 1823 K,holding time of 240 min,and slag composition of 45 wt.%SiO_(2),40 wt.%CaO,and 15 wt.%Al_(2)O_(3).The resulting V-Fe-based alloy predominantly consisted of Fe-based phases such as Fe,titanium(Ti),silicon(Si)and manganese(Mn),with Si,V,as well as chromium(Cr)concentrated in the intercrystalline phase of the Fe-based alloy.The recoveries of Fe,Mn,Cr,V,and Ti under the optimal conditions were 96.30%,91.96%,86.53%,80.29%,and 74.82%,respectively.The key components of the V-Fe-based alloy obtained were 41.96 wt.%Si,27.55 wt.%Fe,12.13 wt.%Mn,5.53 wt.%V,4.86 wt.%Cr,and 3.74 wt.%Ti,thereby enabling the comprehensive recovery of the valuable metal from vanadium slag.展开更多
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
The design and optimization of nonlinear fiber laser sources,such as soliton self-frequency shift(SSFS)tunable sources and supercontinuum(SC)sources,have traditionally relied on manual tuning and simulations,posing ch...The design and optimization of nonlinear fiber laser sources,such as soliton self-frequency shift(SSFS)tunable sources and supercontinuum(SC)sources,have traditionally relied on manual tuning and simulations,posing challenges for real-time applications.Machine learning has shown promise in fiber nonlinear propagation characterization,but the optimization and design of nonlinear systems remain relatively unexplored,especially under multitarget optimization conditions.In this paper,we propose a method that combines deep reinforcement learning(DRL)and deep neural network(DNN)to achieve fast synchronization optimization of ultrafast pulse nonlinear propagation in optical fibers under multitarget optimization tasks,with applications demonstrated in complex SSFS and SC generation systems in the mid-infrared band.The results indicate that a set of optimization parameters can be obtained in a few seconds,enabling rapid,automated tuning of pulse parameters in pursuit of diverse optimization objectives.This integration of DRL and DNN models holds transformative potential for the real-time optimization of not only fiber lasers but also a wide variety of complex photonic systems,paving the way for intelligent,adaptive optical system design and operation.展开更多
Refill friction stir spot welding process is difficultly optimized by accurate modeling because of the high-order functional relationship between welding parameters and joint strength.A database of the welding process...Refill friction stir spot welding process is difficultly optimized by accurate modeling because of the high-order functional relationship between welding parameters and joint strength.A database of the welding process was first established with 6061-T6 aluminum alloy and DP780 galvanized steel as base materials.This dataset was then optimized using a backpropagation neural network.Analyses and mining of the experimental data confirmed the multidimensional mapping relationship between welding parameters and joint strength.Subsequently,intelligent optimization of the welding process and prediction of joint strength were achieved.At the predicted welding parameter(plunging rotation speedω1=1733 r/min,refilling rotation speedω_(2)=1266 r/min,plunging depth p=1.9 mm,and welding speed v=0.5 mm/s),the tensile shear fracture load of the joint reached a maximum value of 10,172 N,while the experimental result was 9980 N,with an error of 1.92%.Furthermore,the correlation of welding parameters-microstructure-joint strength was established.展开更多
Silicone material extrusion(MEX)is widely used for processing liquids and pastes.Owing to the uneven linewidth and elastic extrusion deformation caused by material accumulation,products may exhibit geometric errors an...Silicone material extrusion(MEX)is widely used for processing liquids and pastes.Owing to the uneven linewidth and elastic extrusion deformation caused by material accumulation,products may exhibit geometric errors and performance defects,leading to a decline in product quality and affecting its service life.This study proposes a process parameter optimization method that considers the mechanical properties of printed specimens and production costs.To improve the quality of silicone printing samples and reduce production costs,three machine learning models,kernel extreme learning machine(KELM),support vector regression(SVR),and random forest(RF),were developed to predict these three factors.Training data were obtained through a complete factorial experiment.A new dataset is obtained using the Euclidean distance method,which assigns the elimination factor.It is trained with Bayesian optimization algorithms for parameter optimization,the new dataset is input into the improved double Gaussian extreme learning machine,and finally obtains the improved KELM model.The results showed improved prediction accuracy over SVR and RF.Furthermore,a multi-objective optimization framework was proposed by combining genetic algorithm technology with the improved KELM model.The effectiveness and reasonableness of the model algorithm were verified by comparing the optimized results with the experimental results.展开更多
The surface injection and production system(SIPS)is a critical component for effective injection and production processes in underground natural gas storage.As a vital channel,the rational design of the surface inject...The surface injection and production system(SIPS)is a critical component for effective injection and production processes in underground natural gas storage.As a vital channel,the rational design of the surface injection and production(SIP)pipeline significantly impacts efficiency.This paper focuses on the SIP pipeline and aims to minimize the investment costs of surface projects.An optimization model under harmonized injection and production conditions was constructed to transform the optimization problem of the SIP pipeline design parameters into a detailed analysis of the injection condition model and the production condition model.This paper proposes a hybrid genetic algorithm generalized reduced gradient(HGA-GRG)method,and compares it with the traditional genetic algorithm(GA)in a practical case study.The HGA-GRG demonstrated significant advantages in optimization outcomes,reducing the initial cost by 345.371×10^(4) CNY compared to the GA,validating the effectiveness of the model.By adjusting algorithm parameters,the optimal iterative results of the HGA-GRG were obtained,providing new research insights for the optimal design of a SIPS.展开更多
Increasing the texture complexity of high-performance surfaces can enhance their antifriction properties by altering their distribution and retention of lubricating oils.When a fluid flows through a fish-scale texture...Increasing the texture complexity of high-performance surfaces can enhance their antifriction properties by altering their distribution and retention of lubricating oils.When a fluid flows through a fish-scale texture,a lubricating layer is formed,effectively reducing friction.In this study,a bionic fish-scale structure is proposed,and ceramic components are fabricated and analyzed using micro/nano additive-manufacturing technology.First,the effects of various parameters on the antifriction performance of the fish-scale texture under hydrodynamic lubrication conditions are investigated.Then,the pressure distribution of the oil film—including both positive and negative pressures—is simulated by adjusting parameters such as the angleα,ratio of textured area to total surface area,and depth of the fish-scale texture.The results indicate that for a textured area that accounts for 20%of the total surface,texture depth of 150μm,and angleαof 30°,the pressure differential reaches its maximum.Finally,based on the optimized parameters,the designed fish-scale structure is fabricated using micro/nano ceramic three-dimensional-printing technology.Friction and wear tests are conducted on the sintered samples.The experimental results align well with the simulation data,indicating that the structure can reduce the friction coefficient by approximately 15%,thereby significantly improving the antifriction performance.This study provides a valuable reference for the surface engineering of other high-performance functional structures.展开更多
This work proposes an optimization method for gas storage operation parameters under multi-factor coupled constraints to improve the peak-shaving capacity of gas storage reservoirs while ensuring operational safety.Pr...This work proposes an optimization method for gas storage operation parameters under multi-factor coupled constraints to improve the peak-shaving capacity of gas storage reservoirs while ensuring operational safety.Previous research primarily focused on integrating reservoir,wellbore,and surface facility constraints,often resulting in broad constraint ranges and slow model convergence.To solve this problem,the present study introduces additional constraints on maximum withdrawal rates by combining binomial deliverability equations with material balance equations for closed gas reservoirs,while considering extreme peak-shaving demands.This approach effectively narrows the constraint range.Subsequently,a collaborative optimization model with maximum gas production as the objective function is established,and the model employs a joint solution strategy combining genetic algorithms and numerical simulation techniques.Finally,this methodology was applied to optimize operational parameters for Gas Storage T.The results demonstrate:(1)The convergence of the model was achieved after 6 iterations,which significantly improved the convergence speed of the model;(2)The maximum working gas volume reached 11.605×10^(8) m^(3),which increased by 13.78%compared with the traditional optimization method;(3)This method greatly improves the operation safety and the ultimate peak load balancing capability.The research provides important technical support for the intelligent decision of injection and production parameters of gas storage and improving peak load balancing ability.展开更多
Web pillars enduring complex coupled loads are critical for stability in high-wall mining.This study develops a dynamic failure criterion for web pillars under non-uniform loading using catastrophe theory.Through the ...Web pillars enduring complex coupled loads are critical for stability in high-wall mining.This study develops a dynamic failure criterion for web pillars under non-uniform loading using catastrophe theory.Through the analysis of the web pillar-overburden system’s dynamic stress and deformation,a total potential energy function and dynamic failure criterion were established for web pillars.An optimizing method for web pillar parameters was developed in highwall mining.The dynamic criterion established was used to evaluate the dynamic failure and stability of web pillars under static and dynamic loading.Key findings reveal that vertical displacements exhibit exponential-trigonometric variation under static loads and multi-variable power-law behavior under dynamic blasting.Instability risks arise when the roof’s tensile strength-to-stress ratio drops below 1.Using catastrophe theory,the bifurcation setΔ<0 signals sudden instability.The criterion defines failure as when the unstable web pillar section length l1 exceeds the roof’s critical collapse distance l2.Case studies and simulations determine an optimal web pillar width of 4.6 m.This research enhances safety and resource recovery,providing a theoretical framework for advancing highwall mining technology.展开更多
In this study,a novel synergistic swing energy-regenerative hybrid system(SSEHS)for excavators with a large inertia slewing platform is constructed.With the SSEHS,the pressure boosting and output energy synergy of mul...In this study,a novel synergistic swing energy-regenerative hybrid system(SSEHS)for excavators with a large inertia slewing platform is constructed.With the SSEHS,the pressure boosting and output energy synergy of multiple energy sources can be realized,while the swing braking energy can be recovered and used by means of hydraulic energy.Additionally,considering the system constraints and comprehensive optimization conditions of energy efficiency and dynamic characteristics,an improved multi-objective particle swarm optimization(IMOPSO)combined with an adaptive grid is proposed for parameter optimization of the SSEHS.Meanwhile,a parameter rule-based control strategy is designed,which can switch to a reasonable working mode according to the real-time state.Finally,a physical prototype of a 50-t excavator and its AMESim model is established.The semi-simulation and semi-experiment results demonstrate that compared with a conventional swing system,energy consumption under the 90°rotation condition could be reduced by about 51.4%in the SSEHS before parameter optimization,while the energy-saving efficiency is improved by another 13.2%after parameter optimization.This confirms the effectiveness of the SSEHS and the IMOPSO parameter optimization method proposed in this paper.The IMOPSO algorithm is universal and can be used for parameter matching and optimization of hybrid power systems.展开更多
The high temperature deformation behaviors of α＋β type titanium alloy TC11 （Ti-6.5Al-3.5Mo-1.5Zr-0.3Si） with coarse lamellar starting microstructure were investigated based on the hot compression tests in the tem...The high temperature deformation behaviors of α＋β type titanium alloy TC11 （Ti-6.5Al-3.5Mo-1.5Zr-0.3Si） with coarse lamellar starting microstructure were investigated based on the hot compression tests in the temperature range of 950-1100 ℃ and the strain rate range of 0.001-10 s-1. The processing maps at different strains were then constructed based on the dynamic materials model, and the hot compression process parameters and deformation mechanism were optimized and analyzed, respectively. The results show that the processing maps exhibit two domains with a high efficiency of power dissipation and a flow instability domain with a less efficiency of power dissipation. The types of domains were characterized by convergence and divergence of the efficiency of power dissipation, respectively. The convergent domain in a＋fl phase field is at the temperature of 950-990 ℃ and the strain rate of 0.001-0.01 s^-1, which correspond to a better hot compression process window of α＋β phase field. The peak of efficiency of power dissipation in α＋β phase field is at 950 ℃ and 0.001 s 1, which correspond to the best hot compression process parameters of α＋β phase field. The convergent domain in β phase field is at the temperature of 1020-1080 ℃ and the strain rate of 0.001-0.1 s^-l, which correspond to a better hot compression process window of β phase field. The peak of efficiency of power dissipation in ℃ phase field occurs at 1050 ℃ over the strain rates from 0.001 s^-1 to 0.01 s^-1, which correspond to the best hot compression process parameters of ,8 phase field. The divergence domain occurs at the strain rates above 0.5 s^-1 and in all the tested temperature range, which correspond to flow instability that is manifested as flow localization and indicated by the flow softening phenomenon in stress-- strain curves. The deformation mechanisms of the optimized hot compression process windows in a＋β and β phase fields are identified to be spheroidizing and dynamic recrystallizing controlled by self-diffusion mechanism, respectively. The microstructure observation of the deformed specimens in different domains matches very well with the optimized results.展开更多
The influence of processing parameters on the precision of parts fabricated by fused deposition modeling （FDM） technology is studied based on a series of performed experiments. Processing parameters of FDM in terms ...The influence of processing parameters on the precision of parts fabricated by fused deposition modeling （FDM） technology is studied based on a series of performed experiments. Processing parameters of FDM in terms of wire-width compensation, extrusion velocity, filing velocity, and layer thickness are chosen as the control fac- tors. Robust design analysis and multi-index fuzzy comprehensive assessment method are used to obtain the opti- mal parameters. Results show that the influencing degrees of these four factors on the precision of as-processed parts are different. The optimizations of individual parameters and their combined effects are of the same impor- tance for a high precision manufacturing.展开更多
The paper analyzes the factors influencing machine tool selection. By using fuzzy mathematics theory, we establish a theorietical model for optimal machine tool selection considering geometric features, clamping size,...The paper analyzes the factors influencing machine tool selection. By using fuzzy mathematics theory, we establish a theorietical model for optimal machine tool selection considering geometric features, clamping size, machining range, machining precision and surface roughness. By means of fuzzy comprehensive evaluation method, the membership degree of machine tool selection and the largest comprehensive evaluation index are determined. Then the reasonably automatic selection of machine tool is realized in the generative computer aided process planning （CAPP） system. Finally, the finite element model based on ABAQUS is established and the cutting process of machine tool is simulated. According to the theoretical and empirical cutting parameters and the curve of surface residual stress, the optimal cutting parameters can be determined.展开更多
By the study of extended range guided munitions (ERGM) trajectory characteristics, ERGM free-flight and glide trajectory characteristics are revealed and illustrated. On the basis of free-flight trajectory mathematica...By the study of extended range guided munitions (ERGM) trajectory characteristics, ERGM free-flight and glide trajectory characteristics are revealed and illustrated. On the basis of free-flight trajectory mathematical model, a two-parameter optimization problem of quadrant elevation and rocket ignition time is studied. Using the atmosphere mathematical model, the best glide-starting point of the downward trajectory is determined. With an optimal control mathematical model, the ERGM optimal glide trajectory is obtained.展开更多
Electroless copper plating on diamond particles precoated with 1%Cr was carried out to evaluate the effects of various experimental parameters on coating quality and deposition rate to obtain the optimized reaction pa...Electroless copper plating on diamond particles precoated with 1%Cr was carried out to evaluate the effects of various experimental parameters on coating quality and deposition rate to obtain the optimized reaction parameters. The formulated samples under optimized parameters were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, X-ray photoelectron spectra and optical microscopy. The best parameters, where uniform and maximum coating thickness was achieved, are etching with 20%NaOH for 30 min, sensitization and activation with SnCl2 and PdCl2 for 5 and 20 min, respectively. The composition of the copper solution bath was 16 g/L CuSO4＆#183;5H2O, 35 mL/L formaldehyde （HCHO）, 23 g/L KNaC4H4O6 at 60 ℃, pH=13 and stirring at （350±15） r/min under ultrasonication.展开更多
For density inversion of gravity anomaly data, once the inversion method is determined, the main factors affecting the inversion result are the inversion parameters and subdivision scheme. A set of reasonable inversio...For density inversion of gravity anomaly data, once the inversion method is determined, the main factors affecting the inversion result are the inversion parameters and subdivision scheme. A set of reasonable inversion parameters and subdivision scheme can, not only improve the inversion process efficiency, but also ensure inversion result accuracy. The gravity inversion method based on correlation searching and the golden section algorithm is an effective potential field inversion method. It can be used to invert 2D and 3D physical properties with potential data observed on flat or rough surfaces. In this paper, we introduce in detail the density inversion principles based on correlation searching and the golden section algorithm. Considering that the gold section algorithm is not globally optimized. we present a heuristic method to ensure the inversion result is globally optimized. With a series of model tests, we systematically compare and analyze the inversion result efficiency and accuracy with different parameters. Based on the model test results, we conclude the selection principles for each inversion parameter with which the inversion accuracy can be obviously improved.展开更多
To improve the safety of trains running in an undesirable wind environment,a novel louver-type wind barrier is proposed and further studied in this research using a scaled wind tunnel simulation with 1:40 scale models...To improve the safety of trains running in an undesirable wind environment,a novel louver-type wind barrier is proposed and further studied in this research using a scaled wind tunnel simulation with 1:40 scale models.Based on the aerodynamic performance of the train-bridge system,the parameters of the louver-type wind barrier are optimized.Compared to the case without a wind barrier,it is apparent that the wind barrier improves the running safety of trains,since the maximum reduction of the moment coefficient of the train reaches 58%using the louver-type wind barrier,larger than that achieved with conventional wind barriers(fence-type and grid-type).A louver-type wind barrier has more blade layers,and the rotation angle of the adjustable blade of the louver-type wind barrier is 90–180°(which induces the flow towards the deck surface),which is more favorable for the aerodynamic performance of the train.Comparing the 60°,90°and 120°wind fairings of the louver-type wind barrier blade,the blunt fairing is disadvantageous to the operational safety of the train.展开更多
基金jointly supported by the National Key Research and Development Program of China(2022YFC2106300)the National Nature Science Foundation of China(U2267226).
文摘This study employed the Box-Behnken design in response surface methodology(RSM)to optimize predistillation and pressurized distillation column parameters in methanol distillation.Statistical and fittinganalyses demonstrated the effects of operational parameters and their interactions on product purity and operating costs.Results showed that for methanol mass fraction in the product,the top distillate of the predistillation column(D_(1)),the interaction between D_(1) and the top distillate of the pressurized distillation column(D_(2)),and the interaction between the theoretical plates of the pressurized distillation column(N_(2))and its refluxratio(R_(2))significantlyaffected the outcome,in addition to pressurized distillation column parameters.Acetone mass fraction was mainly influencedby predistillation column parameters and their interactions,with minimal relation to the pressurized distillation column.Operating costs were primarily affected by the refluxratio(R),withdrawal(D)of both columns,and their interactions.Optimization strategies involved increasing theoretical plates and reducing refluxratios compared to the initial plan,achieving energy-saving and consumption-reduction goals.The process required the pressurized distillation column‘s methanol mass fraction to exceed 99.80%,acetone mass fraction below 2×10^(-8),and formaldehyde mass fraction below 5×10^(-9),with a feed rate of 6100 kg·h^(-1).Plans A,B,and C achieved energy-savings of 29.80%,21.78%,and 25.50%respectively,while ensuring separation efficiencyand product quality.This research provides theoretical and practical guidance for optimizing the methanol distillation process,helping to reduce energy consumption and production costs,thereby enhancing corporate competitiveness.
基金supported by Yunnan Fundamental Research Projects(No.202301AT070181)Yunnan Fundamental Research Projects(No.202401CF070126)+1 种基金Xingdian Talent Support Program of Yunnan Province(No.KKRD202203070)Yunnan High level Science and Technology Talents and Innovation Team Selection Special Project(No.202405AS350001).
文摘Fluxgate current sensors(FGCSs)are increasingly employed in power systems due to their high-precision characteristics,yet their measurement flexibility remains constrained by conventional closed-core designs.To address this limitation,we proposed a split-core sensor structure comprising four magnetic core strips,which achieved non-intrusive current measurement while maintaining detection accuracy.An analytical model of the induced electromotive force was established based on the probe’s geometric configuration,followed by finite element simulations to optimize key parameters including core radius,core width,excitation coil turns,and sensing coil configuration.A complete prototype integrating the measurement probe,excitation circuit,and signal processing circuitry was developed and experimentally validated.The experimental results show a sensitivity of 0.1099 V/A,a hysteresis error of 0.559%,and a repeatability error of 1.574%over a measurement range of±10 A.After polynomial fitting-based error compensation,the nonlinearity error was reduced to 0.208%,achieving performance comparable to closed-core sensors.This work provided a practical solution for applications demanding both high measurement accuracy and installation flexibility.
基金supported by the National Key Research and Development Program of China(No.2022YFB3706704)the Academician Special Science Research Project of CCCC(No.YSZX-03-2022-01-B).
文摘To investigate the influence of different longitudinal constraint systems on the longitudinal displacement at the girder ends of a three-tower suspension bridge,this study takes the Cangrong Xunjiang Bridge as an engineering case for finite element analysis.This bridge employs an unprecedented tower-girder constraintmethod,with all vertical supports placed at the transition piers at both ends.This paper aims to study the characteristics of longitudinal displacement control at the girder ends under this novel structure,relying on finite element(FE)analysis.Initially,based on the Weigh In Motion(WIM)data,a random vehicle load model is generated and applied to the finite elementmodel.Several longitudinal constraint systems are proposed,and their effects on the structural response of the bridge are compared.The most reasonable system,balancing girder-end displacement and transitional pier stress,is selected.Subsequently,the study examines the impact of different viscous damper parameters on key structural response indicators,including cumulative longitudinal displacement at the girder ends,maximum longitudinal displacement at the girder ends,cumulative longitudinal displacement at the pier tops,maximum longitudinal displacement at the pier tops,longitudinal acceleration at the pier tops,and maximum bending moment at the pier bottoms.Finally,the coefficient of variation(CV)-TOPSIS method is used to optimize the viscous damper parameters for multiple objectives.The results show that adding viscous dampers at the side towers,in addition to the existing longitudinal limit bearings at the central tower,can most effectively reduce the response of structural indicators.The changes in these indicators are not entirely consistent with variations in damping coefficient and velocity exponent.The damper parameters significantly influence cumulative longitudinal displacement at the girder ends,cumulative longitudinal displacement at the pier tops,and maximum bending moments at the pier bottoms.The optimal damper parameters are found to be a damping coefficient of 5000 kN/(m/s)0.2 and a velocity exponent of 0.2.
基金the financial support provided by the National Key R&D Program of China(Grant No.2023YFC3903900)the Science and Technology Innovation Talent Program of Hubei Province(Grant No.2022EJD002)+1 种基金the Sichuan Science and Technology Program(Grant No.2025ZNSFSC0378)the Key Laboratory of Green Chemistry of Sichuan Institutes of Higher Education(Grant No.LZJ2303).
文摘Specialized vanadium(V)-iron(Fe)-based alloy additives utilized in the production of V-containing steels were investigated.Vanadium slag from the Panzhihua region of China was utilized as a raw material to optimize process parameters for the preparation of V-Fe-based alloy via silicon thermal reduction.Experiments were conducted to investigate the effects of reduction temperature,holding time,and slag composition on alloy-slag separation,alloy microstructure,and the oxide content of residual slag,with an emphasis on the recovery of valuable metal elements.The results indicated that the optimal process conditions for silicon thermal reduction were achieved at reduction temperature of 1823 K,holding time of 240 min,and slag composition of 45 wt.%SiO_(2),40 wt.%CaO,and 15 wt.%Al_(2)O_(3).The resulting V-Fe-based alloy predominantly consisted of Fe-based phases such as Fe,titanium(Ti),silicon(Si)and manganese(Mn),with Si,V,as well as chromium(Cr)concentrated in the intercrystalline phase of the Fe-based alloy.The recoveries of Fe,Mn,Cr,V,and Ti under the optimal conditions were 96.30%,91.96%,86.53%,80.29%,and 74.82%,respectively.The key components of the V-Fe-based alloy obtained were 41.96 wt.%Si,27.55 wt.%Fe,12.13 wt.%Mn,5.53 wt.%V,4.86 wt.%Cr,and 3.74 wt.%Ti,thereby enabling the comprehensive recovery of the valuable metal from vanadium slag.
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.
基金supported by the National Natural Science Foundation of China(Grant No.62575051)the Aeronautical Science Foundation of China(Grant No.2023M038080001)+1 种基金the Equipment Pre-research Joint Fund of the Ministry of Education(Grant No.8091B042228)the Science and Technology Project of Sichuan Province(Grant Nos.2023NSFSC1964 and 203NSFSC0033).
文摘The design and optimization of nonlinear fiber laser sources,such as soliton self-frequency shift(SSFS)tunable sources and supercontinuum(SC)sources,have traditionally relied on manual tuning and simulations,posing challenges for real-time applications.Machine learning has shown promise in fiber nonlinear propagation characterization,but the optimization and design of nonlinear systems remain relatively unexplored,especially under multitarget optimization conditions.In this paper,we propose a method that combines deep reinforcement learning(DRL)and deep neural network(DNN)to achieve fast synchronization optimization of ultrafast pulse nonlinear propagation in optical fibers under multitarget optimization tasks,with applications demonstrated in complex SSFS and SC generation systems in the mid-infrared band.The results indicate that a set of optimization parameters can be obtained in a few seconds,enabling rapid,automated tuning of pulse parameters in pursuit of diverse optimization objectives.This integration of DRL and DNN models holds transformative potential for the real-time optimization of not only fiber lasers but also a wide variety of complex photonic systems,paving the way for intelligent,adaptive optical system design and operation.
基金the financial supports provided by the National Key Research and Development Program of China(2023YFE0201500)the National Natural Science Foundation of China(52375315)+2 种基金the Key Talent Plan Project of Guangdong Province(2023TQ07C702)the Research and Development Program in Key Areas of Dongguan(20201200300122)the GDAS’Project of Science and Technology Development(2022GDASZH-2022010203).
文摘Refill friction stir spot welding process is difficultly optimized by accurate modeling because of the high-order functional relationship between welding parameters and joint strength.A database of the welding process was first established with 6061-T6 aluminum alloy and DP780 galvanized steel as base materials.This dataset was then optimized using a backpropagation neural network.Analyses and mining of the experimental data confirmed the multidimensional mapping relationship between welding parameters and joint strength.Subsequently,intelligent optimization of the welding process and prediction of joint strength were achieved.At the predicted welding parameter(plunging rotation speedω1=1733 r/min,refilling rotation speedω_(2)=1266 r/min,plunging depth p=1.9 mm,and welding speed v=0.5 mm/s),the tensile shear fracture load of the joint reached a maximum value of 10,172 N,while the experimental result was 9980 N,with an error of 1.92%.Furthermore,the correlation of welding parameters-microstructure-joint strength was established.
基金supported by the National Key R&D Program of China(No.2022YFA1005204l)。
文摘Silicone material extrusion(MEX)is widely used for processing liquids and pastes.Owing to the uneven linewidth and elastic extrusion deformation caused by material accumulation,products may exhibit geometric errors and performance defects,leading to a decline in product quality and affecting its service life.This study proposes a process parameter optimization method that considers the mechanical properties of printed specimens and production costs.To improve the quality of silicone printing samples and reduce production costs,three machine learning models,kernel extreme learning machine(KELM),support vector regression(SVR),and random forest(RF),were developed to predict these three factors.Training data were obtained through a complete factorial experiment.A new dataset is obtained using the Euclidean distance method,which assigns the elimination factor.It is trained with Bayesian optimization algorithms for parameter optimization,the new dataset is input into the improved double Gaussian extreme learning machine,and finally obtains the improved KELM model.The results showed improved prediction accuracy over SVR and RF.Furthermore,a multi-objective optimization framework was proposed by combining genetic algorithm technology with the improved KELM model.The effectiveness and reasonableness of the model algorithm were verified by comparing the optimized results with the experimental results.
基金the National Natural Science Foundation of China,grant numbers 51704253 and 52474084.
文摘The surface injection and production system(SIPS)is a critical component for effective injection and production processes in underground natural gas storage.As a vital channel,the rational design of the surface injection and production(SIP)pipeline significantly impacts efficiency.This paper focuses on the SIP pipeline and aims to minimize the investment costs of surface projects.An optimization model under harmonized injection and production conditions was constructed to transform the optimization problem of the SIP pipeline design parameters into a detailed analysis of the injection condition model and the production condition model.This paper proposes a hybrid genetic algorithm generalized reduced gradient(HGA-GRG)method,and compares it with the traditional genetic algorithm(GA)in a practical case study.The HGA-GRG demonstrated significant advantages in optimization outcomes,reducing the initial cost by 345.371×10^(4) CNY compared to the GA,validating the effectiveness of the model.By adjusting algorithm parameters,the optimal iterative results of the HGA-GRG were obtained,providing new research insights for the optimal design of a SIPS.
基金supported by Shanghai Collaborative Innovation Project(Grant No.XTCX-KJ-2024-01)the National Natural Science Foundation of China(Grant No.52205493).
文摘Increasing the texture complexity of high-performance surfaces can enhance their antifriction properties by altering their distribution and retention of lubricating oils.When a fluid flows through a fish-scale texture,a lubricating layer is formed,effectively reducing friction.In this study,a bionic fish-scale structure is proposed,and ceramic components are fabricated and analyzed using micro/nano additive-manufacturing technology.First,the effects of various parameters on the antifriction performance of the fish-scale texture under hydrodynamic lubrication conditions are investigated.Then,the pressure distribution of the oil film—including both positive and negative pressures—is simulated by adjusting parameters such as the angleα,ratio of textured area to total surface area,and depth of the fish-scale texture.The results indicate that for a textured area that accounts for 20%of the total surface,texture depth of 150μm,and angleαof 30°,the pressure differential reaches its maximum.Finally,based on the optimized parameters,the designed fish-scale structure is fabricated using micro/nano ceramic three-dimensional-printing technology.Friction and wear tests are conducted on the sintered samples.The experimental results align well with the simulation data,indicating that the structure can reduce the friction coefficient by approximately 15%,thereby significantly improving the antifriction performance.This study provides a valuable reference for the surface engineering of other high-performance functional structures.
基金supported by the Science and Technology Research Program of Chongqing Municipal Education Commission(KJQN202401501,KJZD-M202401501).
文摘This work proposes an optimization method for gas storage operation parameters under multi-factor coupled constraints to improve the peak-shaving capacity of gas storage reservoirs while ensuring operational safety.Previous research primarily focused on integrating reservoir,wellbore,and surface facility constraints,often resulting in broad constraint ranges and slow model convergence.To solve this problem,the present study introduces additional constraints on maximum withdrawal rates by combining binomial deliverability equations with material balance equations for closed gas reservoirs,while considering extreme peak-shaving demands.This approach effectively narrows the constraint range.Subsequently,a collaborative optimization model with maximum gas production as the objective function is established,and the model employs a joint solution strategy combining genetic algorithms and numerical simulation techniques.Finally,this methodology was applied to optimize operational parameters for Gas Storage T.The results demonstrate:(1)The convergence of the model was achieved after 6 iterations,which significantly improved the convergence speed of the model;(2)The maximum working gas volume reached 11.605×10^(8) m^(3),which increased by 13.78%compared with the traditional optimization method;(3)This method greatly improves the operation safety and the ultimate peak load balancing capability.The research provides important technical support for the intelligent decision of injection and production parameters of gas storage and improving peak load balancing ability.
基金supported by the National Natural Science Foundation of China(Nos.52204136,52474100,and 52204092).
文摘Web pillars enduring complex coupled loads are critical for stability in high-wall mining.This study develops a dynamic failure criterion for web pillars under non-uniform loading using catastrophe theory.Through the analysis of the web pillar-overburden system’s dynamic stress and deformation,a total potential energy function and dynamic failure criterion were established for web pillars.An optimizing method for web pillar parameters was developed in highwall mining.The dynamic criterion established was used to evaluate the dynamic failure and stability of web pillars under static and dynamic loading.Key findings reveal that vertical displacements exhibit exponential-trigonometric variation under static loads and multi-variable power-law behavior under dynamic blasting.Instability risks arise when the roof’s tensile strength-to-stress ratio drops below 1.Using catastrophe theory,the bifurcation setΔ<0 signals sudden instability.The criterion defines failure as when the unstable web pillar section length l1 exceeds the roof’s critical collapse distance l2.Case studies and simulations determine an optimal web pillar width of 4.6 m.This research enhances safety and resource recovery,providing a theoretical framework for advancing highwall mining technology.
基金supported by the Changsha Major Science and Technology Plan Project,China(No.kq2207002)the Natural Science Foundation of Hunan Province(No.2023JJ40720)the Postgraduate Innovative Project of Central South University,China(No.2022XQLH058)。
文摘In this study,a novel synergistic swing energy-regenerative hybrid system(SSEHS)for excavators with a large inertia slewing platform is constructed.With the SSEHS,the pressure boosting and output energy synergy of multiple energy sources can be realized,while the swing braking energy can be recovered and used by means of hydraulic energy.Additionally,considering the system constraints and comprehensive optimization conditions of energy efficiency and dynamic characteristics,an improved multi-objective particle swarm optimization(IMOPSO)combined with an adaptive grid is proposed for parameter optimization of the SSEHS.Meanwhile,a parameter rule-based control strategy is designed,which can switch to a reasonable working mode according to the real-time state.Finally,a physical prototype of a 50-t excavator and its AMESim model is established.The semi-simulation and semi-experiment results demonstrate that compared with a conventional swing system,energy consumption under the 90°rotation condition could be reduced by about 51.4%in the SSEHS before parameter optimization,while the energy-saving efficiency is improved by another 13.2%after parameter optimization.This confirms the effectiveness of the SSEHS and the IMOPSO parameter optimization method proposed in this paper.The IMOPSO algorithm is universal and can be used for parameter matching and optimization of hybrid power systems.
基金Project (51005112) supported by the National Natural Science Foundation of ChinaProject (2010ZF56019) supported by the Aviation Science Foundation of China+1 种基金Project (GJJ11156) supported by the Education Commission of Jiangxi Province, ChinaProject(GF200901008) supported by the Open Fund of National Defense Key Disciplines Laboratory of Light Alloy Processing Science and Technology, China
文摘The high temperature deformation behaviors of α＋β type titanium alloy TC11 （Ti-6.5Al-3.5Mo-1.5Zr-0.3Si） with coarse lamellar starting microstructure were investigated based on the hot compression tests in the temperature range of 950-1100 ℃ and the strain rate range of 0.001-10 s-1. The processing maps at different strains were then constructed based on the dynamic materials model, and the hot compression process parameters and deformation mechanism were optimized and analyzed, respectively. The results show that the processing maps exhibit two domains with a high efficiency of power dissipation and a flow instability domain with a less efficiency of power dissipation. The types of domains were characterized by convergence and divergence of the efficiency of power dissipation, respectively. The convergent domain in a＋fl phase field is at the temperature of 950-990 ℃ and the strain rate of 0.001-0.01 s^-1, which correspond to a better hot compression process window of α＋β phase field. The peak of efficiency of power dissipation in α＋β phase field is at 950 ℃ and 0.001 s 1, which correspond to the best hot compression process parameters of α＋β phase field. The convergent domain in β phase field is at the temperature of 1020-1080 ℃ and the strain rate of 0.001-0.1 s^-l, which correspond to a better hot compression process window of β phase field. The peak of efficiency of power dissipation in ℃ phase field occurs at 1050 ℃ over the strain rates from 0.001 s^-1 to 0.01 s^-1, which correspond to the best hot compression process parameters of ,8 phase field. The divergence domain occurs at the strain rates above 0.5 s^-1 and in all the tested temperature range, which correspond to flow instability that is manifested as flow localization and indicated by the flow softening phenomenon in stress-- strain curves. The deformation mechanisms of the optimized hot compression process windows in a＋β and β phase fields are identified to be spheroidizing and dynamic recrystallizing controlled by self-diffusion mechanism, respectively. The microstructure observation of the deformed specimens in different domains matches very well with the optimized results.
基金Supported by the Science and Technology Support Key Project of 12th Five-Year of China(2011BAD20B00-4)~~
文摘The influence of processing parameters on the precision of parts fabricated by fused deposition modeling （FDM） technology is studied based on a series of performed experiments. Processing parameters of FDM in terms of wire-width compensation, extrusion velocity, filing velocity, and layer thickness are chosen as the control fac- tors. Robust design analysis and multi-index fuzzy comprehensive assessment method are used to obtain the opti- mal parameters. Results show that the influencing degrees of these four factors on the precision of as-processed parts are different. The optimizations of individual parameters and their combined effects are of the same impor- tance for a high precision manufacturing.
基金Shanxi Province Science and Technology Research Project(No.20140321008-03)
文摘The paper analyzes the factors influencing machine tool selection. By using fuzzy mathematics theory, we establish a theorietical model for optimal machine tool selection considering geometric features, clamping size, machining range, machining precision and surface roughness. By means of fuzzy comprehensive evaluation method, the membership degree of machine tool selection and the largest comprehensive evaluation index are determined. Then the reasonably automatic selection of machine tool is realized in the generative computer aided process planning （CAPP） system. Finally, the finite element model based on ABAQUS is established and the cutting process of machine tool is simulated. According to the theoretical and empirical cutting parameters and the curve of surface residual stress, the optimal cutting parameters can be determined.
文摘By the study of extended range guided munitions (ERGM) trajectory characteristics, ERGM free-flight and glide trajectory characteristics are revealed and illustrated. On the basis of free-flight trajectory mathematical model, a two-parameter optimization problem of quadrant elevation and rocket ignition time is studied. Using the atmosphere mathematical model, the best glide-starting point of the downward trajectory is determined. With an optimal control mathematical model, the ERGM optimal glide trajectory is obtained.
基金Project(9140A12060110BQ03)supported by the National Key Laboratory of Science and Technology on Materials under Shock and Impact,China
文摘Electroless copper plating on diamond particles precoated with 1%Cr was carried out to evaluate the effects of various experimental parameters on coating quality and deposition rate to obtain the optimized reaction parameters. The formulated samples under optimized parameters were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, X-ray photoelectron spectra and optical microscopy. The best parameters, where uniform and maximum coating thickness was achieved, are etching with 20%NaOH for 30 min, sensitization and activation with SnCl2 and PdCl2 for 5 and 20 min, respectively. The composition of the copper solution bath was 16 g/L CuSO4＆#183;5H2O, 35 mL/L formaldehyde （HCHO）, 23 g/L KNaC4H4O6 at 60 ℃, pH=13 and stirring at （350±15） r/min under ultrasonication.
基金supported by Specialized Research Fund for the Doctoral Program of Higher Education of China(20110022120004)the Fundamental Research Funds for the Central Universities
文摘For density inversion of gravity anomaly data, once the inversion method is determined, the main factors affecting the inversion result are the inversion parameters and subdivision scheme. A set of reasonable inversion parameters and subdivision scheme can, not only improve the inversion process efficiency, but also ensure inversion result accuracy. The gravity inversion method based on correlation searching and the golden section algorithm is an effective potential field inversion method. It can be used to invert 2D and 3D physical properties with potential data observed on flat or rough surfaces. In this paper, we introduce in detail the density inversion principles based on correlation searching and the golden section algorithm. Considering that the gold section algorithm is not globally optimized. we present a heuristic method to ensure the inversion result is globally optimized. With a series of model tests, we systematically compare and analyze the inversion result efficiency and accuracy with different parameters. Based on the model test results, we conclude the selection principles for each inversion parameter with which the inversion accuracy can be obviously improved.
基金Project(2017T001-G)supported by the Science and Technology Research and Development Program of China Railway CorporationProject(2017YFB1201204)supported by the National Key Research and Development Program of China+2 种基金Project(U1534206)supported by the National Natural Science Foundation of ChinaProject(2015CX006)supported by the Innovation-driven Plan in Central South University,ChinaProject(2017zzts521)supported by the Fundamental Research Funds for the Central Universities,China
文摘To improve the safety of trains running in an undesirable wind environment,a novel louver-type wind barrier is proposed and further studied in this research using a scaled wind tunnel simulation with 1:40 scale models.Based on the aerodynamic performance of the train-bridge system,the parameters of the louver-type wind barrier are optimized.Compared to the case without a wind barrier,it is apparent that the wind barrier improves the running safety of trains,since the maximum reduction of the moment coefficient of the train reaches 58%using the louver-type wind barrier,larger than that achieved with conventional wind barriers(fence-type and grid-type).A louver-type wind barrier has more blade layers,and the rotation angle of the adjustable blade of the louver-type wind barrier is 90–180°(which induces the flow towards the deck surface),which is more favorable for the aerodynamic performance of the train.Comparing the 60°,90°and 120°wind fairings of the louver-type wind barrier blade,the blunt fairing is disadvantageous to the operational safety of the train.
