最新刊期
卷 59 ， 期 4 ， 2025
- 摘要：The drive and transmission system is a crucial component of electric vehicles. An efficient and energy-saving drive and transmission system plays a significant role in enhancing the power performance, economic efficiency, and handling stability of electric vehicles. The research advancements of the drive and transmission structure of electric vehicles, both domestically and internationally, are explored, focusing on the principles and characteristics of different driving modes, the classification of multi-motor coupling methods, and typical applications. Regarding the principles and characteristics of driving modes, the operating patterns, advantages, and disadvantages of single-motor drive, single-motor drive with transmission, dual-motor coupling drive, and multi-motor drive systems are analyzed and summarized, highlighting the challenges faced by the single-motor drive system, including low motor efficiency, inadequate power performance, and limited energy conservation. On the other hand, multi-motor drives are shown to enhance the efficiency of the drive system and extend the driving range through multiple working modes, making them the primary drive and transmission structure for future electric vehicles. In terms of the classification of multi-motor coupling methods, the fundamental principles and current research status of three multi-motor coupling methods, i.e. speed coupling, torque coupling, and speed-torque coupling, are summarized in detail, with the speed-torque coupling drive system being specifically recommended for its ability to dynamically allocate power from multiple motors, enhancing the overall efficiency of the drive system under low-speed heavy-load and high-speed light-load road conditions, thereby offering superior comprehensive performance. Additionally, existing hub motor systems, wheel-side motor systems, and single-bridge single-motor + single-bridge dual-motor drive systems are reviewed. Further analysis suggests that the future drive system of electric vehicles should transition towards multi-power sources, integration, and electromechanical coupling. This research serves a valuable reference for the development of drive and transmission systems of future electric vehicles.关键词：electric vehicle;drive and transmission;speed coupling;torque coupling;energy saving501|57|0更新时间：2026-01-06
- 摘要：Aiming at electric trucks adopt a driving configuration of a central motor combined with a gearbox, leading to issues such as high-power consumption of the driving motor, difficult spatial arrangement of the transmission system, and low transmission efficiency. Taking the Shaanxi automobile Delong M3000 series 18 t tractor as the research object, a novel dual-motor dual-planetary wheel-side distributed drive system capable of dual-motor torque-coupling drive and single-motor drive modes is proposed. The basic parameters of the dual permanent magnet synchronous motors in the new drive system are theoretically calculated. A joint simulation platform based on the Workbench platform and the Maxwell software is established, and a multi-objective optimization method for dual-motor parameters using genetic algorithms is proposed to obtain the optimal solutions for output torque, torque fluctuation rate, and maximum back electromotive force. The mechanical structure assembly of dual motors and dual planetary gears with rated powers of 60 and 30 kW, and rated speeds of 3 500 and 1 500 r/min, respectively, is designed, manufactured, installed, and tested along with a computer experimental platform. A vehicle control strategy based on logical threshold values and a motor control scheme based on vector control are developed, and experiments on motor performance in two operating modes and mode switching are conducted. The research results indicate that the designed dual-motor dual-planetary gear train drive system exhibits a maximum speed fluctuation rate of 2.58% and a maximum torque fluctuation rate of 5.5% in both operating modes, showing good output response and providing a reference for practical applications of this principle.关键词：electric truck;drive and transmission;permanent magnet synchronous motor;planetary gear train120|71|0更新时间：2026-01-06
- 摘要：The stator winding of the asynchronous motor used in electric vehicles has a fixed number of poles, resulting in poor low-speed traction capability, limited speed variation, and power range. To achieve a larger gear ratio, most electric vehicles use multi-stage planetary gear transmission, leading to bulky reducer sizes. In this paper, taking a certain type of SUV passenger car as the research background, a novel principle system for electric vehicle drive transmission is proposed, which combines a variable-pole alternating current three-phase asynchronous motor with a duplex planetary gear system. The reduction ratio and structural scheme of the duplex planetary gear system are theoretically calculated, and the dynamic model of the combination of the variable-pole motor and duplex planetary gear system, as well as the new theory of variable-pole motor design, are established. The efficiency maps of the motor under different pole numbers are simulated and different control modes of the variable-pole motor under different operating conditions are proposed for optimal control. A variable-pole motor and duplex planetary gear system mechanical structure assembly with a rated power of 59 kW and rated speeds of 4 000 and 8 000 r/min respectively are designed, manufactured, installed, and debugged, along with a computer test platform. Variable-pole switching tests, incremental speed regulation tests, and decremental speed regulation tests are carried out. The research results demonstrate that the novel principle system can achieve a powertrain with a reduction ratio of 10, which is more compact in structure and has a wider speed range, thus confirming the validity of this new drive transmission principle.关键词：electric passenger car;variable-pole alternating current asynchronous motor;duplex planetary gear reducer;dynamic modeling;control mode70|36|0更新时间：2026-01-06
Special Topic New Principles and Intelligent Control of Drive and Transmission for New Energy Vehicles
- 摘要：To address the issue of traditional under-relaxation factor selection overly reliant on computational experience and overlooking inherent flow field characteristics, a method for automatically acquiring under-relaxation factors driven by flow field characteristics is proposed. For the semi-implicit method for pressure-linked equations (SIMPLE) series algorithm, a quantity representing the velocity distribution based on the velocity gradient of the flow field is provided. Utilizing a nonlinear function to transform this quantity, an expression for calculating the velocity under-relaxation factor is derived. Comparative analyses of fixed under-relaxation factors and the automatic acquisition method are conducted in three classic cases of lid-driven flow, backward-facing step flow, and tank flow under first-order upwind, quadratic upwind interpolation of convective kinematics (QUICK), and stability-guaranteed second-order difference schemes. The results show that the proposed automatic acquisition method yields computation times comparable to the shortest computation times under fixed under-relaxation factors in all cases and discretization schemes, and in some scenarios, even shorter than the shortest computation time under fixed under-relaxation factors. In the case of the backward-facing step flow with grid sizes of 30×180 and 30×210 under the QUICK scheme, computations do not converge with fixed under-relaxation factors set at 0.1, 0.5, and 0.9, but converge when using the proposed automatic acquisition method. The residual values obtained using the automatic acquisition method can reach the order of 10－14, equivalent to the order of fixed under-relaxation factors under convergence conditions. This research provides a reference for further optimizing automatic under-relaxation factor acquisition methods.关键词：SIMPLE algorithm;finite volume method;high-order scheme;under-relaxation factors66|13|0更新时间：2026-01-06
- 摘要：For a single-cylinder direct-injection spark-ignition lean-burn methanol engine, the influence of multiple injection strategies on engine performance is investigated. Three experimental groups with three different injection strategies are selected for a total of 22 operating conditions to explore the impact of varying injection frequencies, timing, and fuel proportions on the engine's power, economy, and emissions performance. The research results show that compared to single injection, multiple injections can effectively optimize the in-cylinder combustion process of methanol engines, concentrating the maximum in-cylinder pressure and its corresponding crank angle distribution, significantly reducing the number of degradation cycles by up to 85% and cycle-to-cycle variations by up to 65%. While multiple injections may lead to increased CO and HC emissions compared to single injection, systematic optimization of injection and ignition parameters can reduce NOx emissions. Under the conditions of this study, the optimal performance is achieved with injection timings of 270°, 180°, and 90° before top dead center for the three injections, with fuel proportions of 0.38, 0.42, and 0.20, respectively. The engine achieves the best comprehensive performance with these settings. Overall, the engine's comprehensive performance under the three injection strategy surpasses that of one or two injections, indicating that the three-injection strategy has higher potential for optimizing the engine's comprehensive performance.关键词：methanol;lean burn;multiple-injection;thermal efficiency;emissions characteristics67|15|0更新时间：2026-01-06
- 摘要：In response to the changes in mechanical and electrical properties of polypropylene (PP) after toughening with an elastomer, which leads to a decrease in material's electrical performance due to the introduction of the elastomer, a blend method is employed to add different mass fractions of polyolefin elastomer (POE) into the PP matrix. Firstly, considering research on mechanical and insulation properties of composite materials, the optimal POE ratio for the best overall mechanical-electrical performance is proposed. Furthermore, the space charge accumulation and charge transport characteristics of PP/POE composites at high temperature are analyzed based on the microstructure, thermal transition characteristics and insulation properties of the composites. The research shows that with an increase in POE content, the elastic modulus of PP/POE composites decrease, and the direct current breakdown strength decreases with increasing POE content. Under high electric fields, the electrical conductivity of the composite with wPOE=40% is the lowest among all composites, approximately three times that of PP conductivity. Other composites exhibit electrical conductivities one order of magnitude higher than PP. At 20 ℃, composites with wPOE=50%, 60% respectively show significant anisotropic charge accumulation. At high temperatures, the DC breakdown strength of PP and the composite with wPOE=40% decreases with increasing temperature. The spatial charge performance of PP is relatively stable, while the spatial charge accumulation in the composite with wPOE=40% increases with temperature, especially above 60 ℃, leading to a significant increase in internal space charge. This research reveals that the accumulation of space charge and the dramatic increase in electrical conductivity of PP/POE composites at high temperatures are key issues limiting their insulation performance.关键词：polypropylene/polyolefin elastomer composites;space charge;conduction;breakdown strength57|9|0更新时间：2026-01-06
- 摘要：In response to performance limitations caused by uneven fuel distribution and inadequate water management capabilities in proton exchange membrane fuel cells (PEMFCs), a novel bionic flow field is designed based on the vein structure of begonia leaves, and its performance is systematically investigated through numerical simulation. Firstly, the bionic flow field is developed by mimicking the natural flow patterns of begonia leaf veins. Then, numerical simulation techniques are employed to compare and analyze the flow field performance of the biomimetic flow field, traditional serpentine flow field, and parallel flow field. Finally, the distribution characteristics of limiting current density, peak power density, internal oxygen concentration, and current density are explored. The research results demonstrate that compared to traditional serpentine and parallel flow fields, the biomimetic flow field exhibits lower pressure drop, more uniform oxygen concentration distribution in the catalyst layer, and higher gas supply quality. Furthermore, the biomimetic flow field shows a 35.42% and 6.81% increase in limiting current density, a 29.71% and 5.22% increase in peak power density compared to the parallel and serpentine flow fields, respectively, with improved water retention capabilities compared to the parallel flow field. This research provides a new perspective for optimizing the design of flow fields in PEMFCs, offering significant practical value for enhancing the overall performance and efficiency of fuel cells.关键词：proton exchange membrane fuel cell;biomimetic flow field;begonia leaf veins;bipolar plate55|40|0更新时间：2026-01-06
- 摘要：In response to the challenges of weak characteristics and the influence of grounding transition resistance on line selection for single-phase grounding faults in low-current grounding systems, a line selection method for grounding faults in distribution networks based on the phase similarity of characteristic frequency current is proposed. Firstly, using signal injection method, the distribution of zero-sequence current and characteristic current signal distribution after a single-phase grounding fault occurs in a low-current grounding system is analyzed to obtain the fault characteristic current distribution pattern. Secondly, the impact of different characteristic frequencies, line lengths, and line topologies on the propagation characteristics of the injected current signals is analyzed, with 220 Hz selected as the characteristic frequency for the injected current. Using the PSCAD/EMTDC platform, a distribution network simulation model is built. After a fault occurs, characteristic frequency current is injected, and the amplitude and phase characteristics of the characteristic frequency signals for each line are analyzed. By utilizing the phase of the characteristic frequency current, a line selection method based on the phase similarity of characteristic frequency currents is proposed, and criteria for single-phase grounding fault line selection are established. Simulation examples are conducted for different grounding transition resistance conditions of single-phase grounding faults, and line selection is performed using the proposed method. Results show that under high-resistance grounding conditions, the proposed method can accurately identify the faulty line with high sensitivity and accuracy. Compared to traditional line selection methods, the proposed method has lower complexity and can handle grounding transition resistance up to 10 kΩ. This method provides a new perspective for the theoretical research on line selection for single-phase grounding faults in low-current grounding systems.关键词：distribution network;single phase ground fault;signal injection;fault line selection;current phase similarity36|18|0更新时间：2026-01-06
- 摘要：In order to address the issue of numerous and interrelated resonance parameters in high-order compensated wireless power transmission (WPT) systems, which makes it challenging to determine specific component parameters during system design, a parameter optimization method for WPT systems with primary-side LCC and secondary-side LC series compensation topology (LCC-S) is proposed. By utilizing MATLAB/Simulink to construct a WPT system simulation platform and conducting theoretical analysis, the impact of resonance parameters, coupling coefficients, and equivalent loads on the system's output characteristics is evaluated. The variables with the most complex impact are selected as decision variables to construct a nonlinear optimization model. Aiming to improve the transmission efficiency of the WPT system, a nonlinear optimization strategy is incorporated into the genetic algorithm, and a new mutation function is designed. An optimized design scheme for system parameters is provided using the improved genetic algorithm (IGA). Simulation results demonstrate that the IGA achieves a system transmission efficiency of 98.34%, a 2.52% improvement over the genetic algorithm, with significantly enhanced convergence speed. An experimental platform for the WPT system is constructed and tested, showing that the system can maintain a power output of 300 W with an efficiency of 97.98%. When the load resistance ranges from 6 to 46 Ω, the system's transmission efficiency can be maintained above 90%. The research findings can serve as a reference for parameter design of LCC-S type WPT systems.关键词：wireless power transmission;LCC-S type;topology structure;improved genetic algorithm;resonant parameter optimization58|41|0更新时间：2026-01-06
- 摘要：To accurately estimate the state of health (SOH) of lithium-ion batteries, a convolutional neural network-residual-BiGRU-attention (CNN-Residual-BiGRU-Attention) model and fine-tuning estimation method are proposed. Firstly, a piecewise approximate aggregation algorithm is used to reduce the dimensionality of battery capacity increment and constant current charging curves to construct a global health factor. Secondly, the CNN is used to extract the temporal features of the global health factor, highlighting strong correlations through an attention mechanism, and the residual network is introduced to maintain information integrity. Finally, by improving the artificial bee colony algorithm for model hyperparameter optimization, the accuracy of SOH estimation is enhanced. The accuracy is validated using lithium-ion battery datasets from NASA and the University of Oxford. The results show that, even with a less accurate convolutional neural network-long short-term memory model, the proposed fine-tuning estimation method keeps the mean absolute error eMAE, mean absolute percentage error eMAPE, and root mean square error eRMSE of the SOH estimation results within 2%. Compared with the CNN-BiGRU-Attention model, when the CNN-Residual-BiGRU-Attention model is employed to estimate the SOH of the same battery with a training set ratio of 30%, the eMAE、eMAPE and eRMSE of the estimated results are reduced by 41.86%, 44.35% and 42.11%, respectively. For estimating the SOH of the same type of batteries with a training set ratio of 40%, the eMAE、eMAPE and eRMSE of the estimated results are reduced by 45.51%, 45.93%, and 40.10%, respectively. These research findings provide a theoretical reference for accurately estimating the SOH of lithium-ion batteries under low training set conditions.关键词：lithium-ion batteries;the state of health estimation;global health factor;improved artificial bee colony algorithm;residual;bidirectional gated recurrent unit33|21|0更新时间：2026-01-06
- 摘要：In response to the electromagnetic coupling effects, such as the decrease in electromagnetic force in two dimensions and intensified fluctuations, caused by primary core saturation in orthogonal winding planar induction motors, this research initially compares the magnitude and distribution patterns of primary core magnetic flux density when two sets of windings are separately and simultaneously energized through a three-dimensional electromagnetic field simulation model. Subsequently, a semi-analytical method and an analytical method for calculating the saturation effect correction coefficient are obtained by combining Ampere's law with numerical electromagnetic field calculations and iterative calculations of permeability. These methods are then used to assess the impact of energizing currents and slip frequencies of the two winding sets on the electromagnetic coupling effects in the motor. Finally, a locked rotor test is conducted on a prototype to validate the proposed methods. The research findings indicate that as the winding currents increase and the slip frequency decreases in both dimensions, the saturation effect correction coefficient diminishes, leading to a stronger electromagnetic coupling effect. In one dimension, electromagnetic force decreases with the increase in energizing current of the winding in the other dimension, while the fluctuation of electromagnetic force increases correspondingly. Compared to experimental data, the maximum errors in electromagnetic torque calculated using the semi-analytical and analytical methods are 4.78% and 8.56%, respectively, validating the accuracy of the proposed calculation methods. This research provides theoretical guidance for the initial design of orthogonal winding planar induction motors.关键词：orthogonal winding planar induction motor;electromagnetic coupling;core saturation24|26|0更新时间：2026-01-06
- 摘要：To further investigate the key influencing factors during the jet crushing process of the core meltdown material in sodium-cooled fast reactors and deeply analyze the jet crushing morphology, penetration depth, and crushing mechanism, a numerical simulation of the crushing behavior of the meltdown material jet in sodium coolant is carried out based on an improved least-squares moving particle semi-implicit method. Firstly, the applicability and reliability of this method are validated by comparing the simulation results with existing experimental data. Secondly, this method is employed to study the interaction between molten metal and sodium coolant, and numerical simulations of the jet crushing process of the meltdown material jet are conducted, yielding a large amount of numerical experimental results. Finally, based on the simulation results, it is observed that at low Weber numbers, the Rayleigh-Taylor instability at the jet front dominates the crushing process, while at both high and low Weber numbers, the jet crushing is primarily driven by the wave-like peeling mechanism induced by the Kelvin-Helmholtz instability on the lateral surface of the jet. The effects of parameters such as jet diameter and initial velocity on jet breakup length are analyzed, and a correlation formula for the crushing length in sodium coolant was fitted, validated against experimental values and other model results, with errors controlled within ±30%, thus establishing a new jet crushing model. This research can provide valuable references for improving the design of sodium-cooled fast reactor pressure vessels and holds significant importance for evaluating the potential impact of core meltdown material jets on reactor pressure vessels in sodium-cooled fast reactors.关键词：sodium-cooled fast reactor;jet-breakup length;least squares moving particle semi-implicit method27|21|0更新时间：2026-01-06
- 摘要：In response to the challenge of real-time continuous measurement of component concentrations during the operation of auto-cascade refrigeration systems, an online measurement method for the circulating concentration of mixed refrigerant is proposed to accurately measure the circulating component concentrations, thermodynamic parameters, and system efficiency. The online measurement method is based on the composition, mass and energy conservation of components within the system. The circulating concentration of compositions is measured based on temperature, pressure and mass flow rate. An experimental platform for the auto-cascade refrigeration system is established to validate the feasibility of the online measurement method under experimental conditions with cabinet temperatures ranging from －58.6 ℃ to －40.4 ℃. The accuracy of the online measurement of the composition is further verified using gas chromatography single-time static sampling methods. The research findings indicate that temperature, a crucial parameter affecting the composition, shows a deviation of less than 3 K between the experimental and online measurement values. The maximum deviation between the online measurement values of the composition concentration and the sampling measurement values is 4.45%. The uncertainty calculations show that the online measurement uncertainty of composition circulating concentration is below 2.0%, while the online measurement uncertainty of energy efficiency ratio and refrigeration capacity is below 7.5%. The proposed online measurement method can accurately predict the circulating concentration of the mixed refrigerant in auto-cascade refrigeration systems. In comparison with gas chromatography single-time static sampling, it allows for dynamic continuous trends in component concentrations, providing a basis for in-depth analysis of performance changes in mixed refrigerant thermodynamic systems at the component level.关键词：auto-cascade refrigeration system;online measurement method;mixed refrigerant;circulating concentration36|9|0更新时间：2026-01-06
- 摘要：To address the issue of point-of-interest (POI) recommendation and efficient location queries in road networks using multi-objective decision-making techniques, and to overcome the problem of low query efficiency and usability of traditional multi-objective decision-making techniques in road network environments due to the large amount of approximate data generated by increasing data scales, a generalized approximate skyline query (GAA-SQ) algorithm for road networks is proposed. Approximate sets and independent points are constructed based on POI dimensional similarity and road network proximity, and pruning strategies tailored to POI characteristics are designed. The dataset is then reconstructed using approximate sets and independent points. Based on pruning strategies, POIs that do not affect query results when the query location changes are filtered out, and an AA-R*-Tree index is built to enhance query efficiency. Finally, a generalized approximate aggregation domination algorithm is proposed based on the similarity of POI. By selecting representative points to substitute for the approximate set in Skyline computation, redundant calculations are reduced and query results are optimized. Ultimately, a Skyline result set is obtained that satisfies the approximate and integrated ordering of POI. Theoretical analysis and experimental results indicate that high efficiency and feasibility are exhibited by the proposed algorithm for large-scale datasets with substantially similar data. Compared with the Higher-Gsky, MG-EGsky, and GSSK-A algorithms, the proposed algorithm achieves an average efficiency improvement of approximately 14% as data size, query range, and road segments increase, providing faster and more effective decision support for road network users.关键词：road network;Skyline query;multi-objective decision;approximate query;point of interest recommendation21|7|0更新时间：2026-01-06
- 摘要：To address the issue of decreased force measurement performance in piezoelectric six-dimensional force/torque sensors due to inter-dimensional coupling, a decoupling algorithm for piezoelectric six-dimensional force/torque sensors based on long short-term memory neural network (LSTM) is proposed. Firstly, experimental data needed for the decoupling algorithm is obtained through static calibration experiments of the six-dimensional force sensor and processed accordingly. Then, by analyzing the causes of inter-dimensional coupling in sensors and the decoupling principle of the LSTM neural network, an LSTM neural network decoupling model is constructed. Finally, the decoupling algorithm based on the LSTM neural network is used to optimize the multi-dimensional nonlinear characteristics of the sensor output, obtaining the mapping relationship between sensor inputs and outputs after decoupling, and corresponding output data. A comparative analysis is conducted with radial basis function (RBF) and least squares (LS) decoupling algorithms. The research results show that the maximum repeatability error of the four-point supported piezoelectric six-dimensional force sensor is 1.55%. After utilizing the LSTM-based neural network algorithm for decoupling, the maximum nonlinear error and cross-coupling error of the sensor output results are 0.55% and 0.28% respectively, both lower than those of the RBF and LS algorithms. The LSTM neural network decoupling algorithm effectively reduces inter-dimensional coupling in the six-dimensional force/torque sensor, improving measurement accuracy and holding important implications for the development of the aerospace industry.关键词：six-dimensional force/torque sensor;piezoelectric sensor;decoupling algorithm;long short-term memory neural network;interdimensional coupling48|57|0更新时间：2026-01-06
- 摘要：In response to the issue of frequency band mixing caused by energy orientation in the decomposition of impact vibration frequency bands related to bearing faults using non-negative matrix factorization (NMF), a multi-constrained robust non-negative matrix factorization method for adaptive decomposition of impact fault bands is proposed. Firstly, an error function with adaptive weighted β-divergence is utilized to mitigate risks arising from unknown signal distributions, with the number of signal frequency bands serving as a reference for selecting the decomposition rank. Adaptive band division is achieved by imposing orthogonal constraints on the basis matrix. Secondly, considering the smooth frequency domain of the periodic impact response spectrogram and the sparse time domain characteristics, physically meaningful smooth and sparse constraints are introduced to establish a multi-constrained robust non-negative matrix factorization model tailored to vibration time-frequency spectra. Finally, a solution algorithm is designed leveraging regularization techniques and Stiefel manifold optimization methods. Simulation and experimental results demonstrate that, compared to various NMF methods and typical band selection methods, when facing weak impacts caused by defects, the low-frequency range often harbors multiple sources of interference. The proposed decomposition model accurately extracts the impact response bands in the high-frequency range, circumventing the shortcomings of traditional energy-oriented band decomposition methods. The introduction of constraints effectively enhances the solution results of NMF, reinforcing its discriminative capability when dealing with weak impact characteristic frequency bands.关键词：impulse band;non-negative matrix decomposition;multiple constraints;band decomposition41|29|0更新时间：2026-01-06
- 摘要：In response to the asymmetrical deviations in the left and right tooth surfaces caused by the manufacturing and processing of double helical gears, as well as the limitations of traditional axial displacement iterative methods due to error scale, a new axial displacement iterative method is proposed based on a certain type of high-speed train double helical gear. A loaded tooth contact analysis (LTCA) model is established based on the finite element method (FEM) and finite line contacts theory. It considers the difference of helix angles on different meshing points in the load-deformation coordination equation. The Newton iterative method is used to calculate the axial displacement of the driving gear. The LTCA model is employed to analyze the effects of circular arc modification and tooth surface interference angle on meshing excitation and load distribution. The research results indicate that the Newton iterative method is suitable for the LTCA model of double helical gears with different types of different types of errors. Under small errors, the Newton iterative method reduces the calculation time by 70% compared to traditional iterative methods. With the arc modification increasing from 2 μm to 15 μm, the time-varying meshing stiffness decreases by 38%, the average meshing error increases by 39%, and the maximum normal meshing force at the middle of the tooth surface increases from 100 N to 370 N when the input torque is 500 N·m. As the tooth surface stagger angle increases, the average time-varying meshing stiffness increases, the average meshing error decreases, and the phase difference of the stagger angle increases from 0 to π. The amplitude of the time-varying meshing stiffness and meshing error decreases by 54% and 79%, respectively. These research findings provide new insights for improving the meshing stability of double helical gears.关键词：herringbone gear;loaded contact analysis;lead crowning modification;tooth surface stagger angle;axial displacement;Newton's iteration method19|26|0更新时间：2026-01-06
- 摘要：To address the issue of low estimation accuracy in existing direction of arrival (DOA) estimation algorithms under impulsive noise, an off-grid approximation l0-norm DOA estimation algorithm based on phased fractional low-order moments (PFLOM) and exponential family distribution functions is proposed. Firstly, PFLOM is employed to suppress impulsive noise and construct a sparse DOA model. Secondly, by analyzing the smoothness and steepness of smoothing functions, a family of functions with variable smoothness and steepness is constructed. This function family is used to solve the initial support set. Then, a forward-looking and backward-extending strategy is introduced to expand the initial support set, selecting a group of support sets that minimizes the residual to determine the optimal support set for grid-based DOA estimation. Finally, to address grid mismatch effects, the joint sparsity between DOA coarse estimates and off-grid deviation is used to jointly solve DOA coarse estimates and off-grid deviations through alternating direction iterative methods to obtain off-grid DOA estimate. Simulation results show that, compared to the orthogonal matching pursuit algorithm, the proposed algorithm improves the DOA estimation accuracy by 66.36% at a signal-to-noise ratio of-8dB. Furthermore, when the impulsive noise characteristic index exceeds 0.6, the estimation error of the target DOA by the proposed algorithm can be controlled within 1°. These results demonstrate that the proposed algorithm can achieve high-precision DOA estimation under impulsive noise.关键词：direction of arrival estimation;approximate l0-norm;impulsive noise;exponential family distribution function;forward exploration;backward extension45|15|0更新时间：2026-01-06
- 摘要：To reduce the energy consumption of the rectisol process and increase CO2 capture, scenarios are proposed to use a liquid expander at different locations to replace the throttle valve. Aspen Plus software simulates the traditional rectisol process (scenario 0). The physical method selects the CPA (cubic-plus-association) model and corrects it using binary interaction parameters regressed on experimental data, with standard deviations of the main flow strands from actual data below 1%. Throttle valves are then replaced with a carbon-rich expander, a sulfur-rich expander, and both carbon-rich/sulfur-rich expanders (scenarios 1—3) to enhance the process. Subsequently, sensitivity parameters serve as optimization variables, considering varying levels of heat, cold, and electricity, optimizing process parameters with the objective of overall energy consumption per unit of CO2 product, and obtaining the corresponding optimization scenarios. Results show that applying the liquid expander (scenarios 1—3) reduces energy consumption per unit of CO2 product by 11.75%, 12.38%, and 22.90%, respectively, compared to using a throttle valve; further reductions of 6.05%, 5.59%, and 4.47% are achieved post-optimization. Exergy efficiency increases by 1.23%, 1.23%, and 2.48% for scenarios 1—3, respectively; post-optimization, it further increases by 0.20%, 0.15%, and 0.15%. Economic analysis indicates that different expander positions all yield gains, with optimization slightly boosting profits of the sulfur-rich expander but significantly reducing profits of the carbon-rich expander. This research can provide a reference for the industrial application of liquid expanders.关键词：rectisol;liquid expander;economic analysis;carbon dioxide capture;energy analysis21|23|0更新时间：2026-01-06
- 摘要：To investigate the initial flow characteristics of vortices during the evolution of aircraft wake, a novel method for calculating the initial characteristic parameters of wakes based on the attached vortex model is proposed to accurately calculate characteristic parameters such as the initial wake circulation, vortex core spacing, and vortex core radius in the near field of aircraft wakes. The near-field wake characteristics of a NACA0012 straight wing are numerically simulated in three dimensions using the SST k-ω turbulent model. The near-field wake flow characteristics under three aspect ratios, three angles of attack, and three freestream velocities are analyzed. The simulated results are validated and analyzed using the attached vortex model, and a calculation model for the initial flow characteristic parameters of near-field wakes is established. The findings indicate that compared to traditional methods that rely on maximum vorticity and minimum pressure positions to determine vortex core locations, the method of determining the vortex core position and radius based on the wake velocity distribution calculated by the attached vortex model is more accurate. The near-field wake circulation closely aligns with predictions from the Rankine model. By using the fitted distribution of the wing spanwise attached vortex circulation, the average error of wake circulation calculation is 7%, and the average error of vortex core spacing and vortex core radius calculation is 15%. The method of calculating the initial characteristic parameters of wakes based on the attached vortex model is more accurate and universal than the method based on the elliptical load wing calculation.关键词：wake flow;wake vortex field;attached vortex;numerical simulation28|26|0更新时间：2026-01-06
- 摘要：In order to address the urgent need for the treatment of phosphorus-containing wastewater within 40 seconds to avoid environmental risks, an active micron zero-valent iron (mZVI) is prepared by hydrogen peroxide-hydrochloric acid (H2O2-HCl) activation and combined with calcium oxide (CaO) to form a composite system. This system reduces the phosphorus concentration in wastewater to below 0.2 mg/L and maintains the pH value between 6 and 9 (surface water class Ⅲ standard) within 40 seconds. Firstly, experiments are conducted separately by adding CaO and active micron iron. Subsequently, phosphorus-containing wastewater is treated using the active micron iron/CaO composite system, and its phosphorus removal mechanism is studied. Finally, stability tests are carried out, followed by continuous flow experiments under simulated field conditions. Experimental results show tha the combined addition of CaO and active micron iron can meet the surface water class Ⅲ standard for phosphorus in wastewater within 40 seconds. H2O2-HCl accelerates the oxidation and corrosion of mZVI, providing active adsorption sites Fe3O4, effectively adsorbing phosphate ions and forming Fe-P compounds mainly composed of Fe2(PO4)3 and FePO4. Through chemical precipitation, CaO reacts with phosphates to produce Ca-P compounds, mainly Ca5(PO4)3(OH), achieving an organic combination of chemical precipitation and adsorption. In stability tests lasting up to 28 days and continuous flow experiments, the phosphorus concentration and pH value of the treated wastewater remain stable after treatment with active micron iron/CaO, meeting the surface water class Ⅲ standard within 40 seconds. These research findings provide a theoretical basis for the emergency treatment of phosphorus-containing wastewater.关键词：phosphorus-containing wastewater;quick processing;activated micron iron;calcium oxide;pH value74|24|0更新时间：2026-01-06
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