最新刊期
- 摘要：With the rapid development of high power density DC-DC switching power supplies， thermal management of power modules faces severe challenges. Accurate temperature measurement is the core aspect of thermal management design， while traditional single-method temperature measurement struggles to balance measurement accuracy and real-time performance under both steady-state and dynamic conditions. This paper addressed the accuracy limitations of conventional temperature measurement methods in the thermal management of high power density DC-DC power modules and proposed a temperature compensation model based on multi-source data fusion. The model comprehensively utilized infrared thermal images with dynamically calibrated emissivity， thermocouple measurements， and ANSYS finite element thermal simulation results， taking embedded MEMS sensor measurements as the benchmark. By calculating measurement deviations and error variances， static weights were constructed， while dynamic response factors were introduced based on load current change rate and temperature change rate to adjust the weight distribution of each temperature measurement method in real time. This enabled weighted fusion compensation of temperature data under different operating conditions. Experimental results show that the model maintains a maximum steady-state temperature measurement error within 1.0 ℃ and an average error below 0.7 ℃ under full-load and partial-load conditions. During dynamic load step tests， the dynamic response error is controlled within 1.0 ℃， with a response time of approximately 1.1s. Under environmental temperature （-55~100 ℃） and wind speed （0~3m/s） disturbances， the model achieves an average error below 1.5 ℃ and a maximum error not exceeding 2.0 ℃， demonstrating good environmental robustness. Compared with Dempster-Shafer evidence theory and Kalman filter methods， the proposed model performs more balanced in terms of steady-state accuracy， dynamic error control， and environmental adaptability. The presented model achieves high-precision and high-reliability monitoring of key device temperatures in DC-DC power supplies without damaging device packaging or significantly increasing costs， providing effective data support for power supply thermal design and system optimization.关键词：DC-DC power;thermal error;multi-source data fusion;thermal assessment28|13|0更新时间：2026-06-15
- 摘要：Due to the volatile， flammable， and explosive characteristics of cloud explosive agents， as well as the limited research on dedicated gas leakage monitoring during the warhead loading process， a distributed gas leakage detection system based on the RS485 bus was developed. The system consists of detection units， a data bus， and a monitoring terminal， enabling the acquisition， processing， transmission， analysis， and alarm of flammable and explosive gas concentration data. In the hardware design， photoionization detector （PID） sensors and an RS485 communication architecture were adopted， and the signal conditioning circuit， analog-to-digital conversion module， memory module， microcontroller unit， bus driver， and host computer module were designed. In the software design， a Qt-based host computer platform was established to realize system initialization， status query， parameter configuration， data acquisition， sensitivity calibration， data upload， data analysis， information visualization， and over-threshold alarm functions. To verify the system performance， detection devices were set up in the storage area， measurement area， mixing area and pouring area of the production workshop， and a 26-hour continuous test was conducted. The results show that the system can stably complete the collection and transmission of multi-node concentrations at intervals of 15 min， and the overall volume fraction of the test gas on site is within the range from 0 to 5×10-6， which is below the alarm threshold of 10×10-6. The proposed system demonstrates strong anti-interference capability， high detection sensitivity， and good engineering applicability， and can provide reliable technical support for the safe loading of cloud explosive warheads through unattended， continuous， real-time， and high-precision monitoring.关键词：RS485 bus distributed detection;photoionization detection;PID sensor application;flammable and explosive gases;gas leakage detection13|14|0更新时间：2026-06-15
- 摘要：By introducing an indirect infection compartment to account for potential transmission through contaminated objects in the environment， we established an
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Design and Analysis of Wide⁃Angle Dual⁃Band Terahertz Polarization Selector Based on Metasurface AI导读
摘要：In recent years， single-band terahertz polarization-selective devices have struggled to meet the demands for multifunctional integration and spectral multiplexing required by applications such as polarization imaging， spectral detection， and wireless communication. Meanwhile， existing dual-band polarization-selective metasurfaces suffer from issues like insufficient incident angle stability and poor independence between different operational bands， limiting their performance in real-world， complex conditions. This paper proposes and demonstrates a dual-band linear-dichroic terahertz metasurface. Using an internally open asymmetric subwavelength unit structure， the device achieves efficient and independent control of orthogonal linearly polarized terahertz waves at two distinct frequency bands. Simulation results show that the device reaches linear dichroism values of 0.943 and 0.972 at 0.483 THz and 0.72 THz， respectively， with independent tunability for both bands. The 3 dB effective operating bandwidths are 0.475-0.490 THz and 0.709-0.731 THz， respectively. Field distribution analysis reveals that under TE polarization， the low-frequency and high-frequency responses are dominated by electric dipole and coupled resonance modes， respectively. Under TM polarization， the low-frequency response is governed by magnetic dipole resonance， while the high-frequency response is dominated by a current loop in the metallic ring. Impedance analysis shows that the normalized impedances at the two resonant frequencies are ideally matched to free space. This matching property results in pronounced absorption contrast between orthogonal linearly polarized terahertz waves at the two operating bands， laying a critical foundation for dual-band high linear dichroism. Angle-dependent tests demonstrate that polarization-selective efficiency remains above 90% from 0° to 35° incident angles， and even at 50° incident angle， efficiency stays around 80%， showing excellent angle stability and practical application potential. This research provides new insights and experimental basis for the design and application of high-performance， multi-frequency， wide-angle terahertz polarization control devices.关键词：polarization control;metasurface;linear dichroism;terahertz15|9|0更新时间：2026-06-15 - 摘要：Addressing the challenges of directly observing the internal mechanical behavior of polymer bonded explosives （PBX） during the compression molding process and the lack of intuitive basis for process optimization， a secondary development of the ABAQUS simulation software was conducted. Based on the Qt Creator platform， a parametric simulation software for compression molding was constructed， enabling the investigation of the impact of compression process parameters on the internal stress transfer within the charge and the densification mechanism of explosive molding powder. The constitutive model for compression-molded PBX explosive materials selected the Drucker-Prager Cap model， which accurately described the plastic deformation and volumetric compression behavior of molding powder. Parameter calibration and verification of the hardening law were completed through experiments. The results show that the simulation results are highly consistent with uniaxial compression experimental data， confirming that the constitutive model effectively characterizes the nonlinear hardening behavior of the material. Through parametric simulation comparisons， the inherent mechanisms of single-punch and double-punch compression molding processes were revealed. Due to the friction attenuation effect in stress transfer， the single-punch process results in a significant stress gradient and a density distribution that is high at the top and low at the bottom along the axial direction of the charge column. In contrast， the double-punch process reconstructs the stress transfer path through bidirectional symmetric loading， enhancing the uniformity of the stress field， thereby achieving a more uniform density distribution throughout the charge column. The parametric simulation software for compression molding provides efficient technical support for analyzing the mechanism and optimizing the process of PBX explosive compression molding.关键词：polymer bonded explosive;press forming;stress transfer;densification;parametric simulation17|12|0更新时间：2026-06-15
- 摘要：In standalone ground-based navigation and positioning networks， the use of low-cost temperature-compensated voltage-controlled crystal oscillators （TCVCXOs） at base stations introduces clock drift， degrading positioning and timing accuracy. To address this problem， a novel ground navigation system architecture is designed based on the principle of coherent forwarding， featuring collaborative operation between a master station and slave stations.The master station employs a dual-frequency synchronous transmission mode， simultaneously emitting synchronization signals and positioning signals that maintain mutual coherence. Each slave station integrates a full-duplex transceiver module. Its receiving channel establishes a tracking loop to achieve phase-locking with the master station’s synchronization signals. Leveraging the coherent mapping relationship between the master’s synchronization and positioning signals， the slave station’s transmitting channel generates a local positioning signal that is frequency and phase synchronized with the master’s positioning signal. This coherent forwarding mechanism ensures synchronization across the network.Experimental test results demonstrate that this approach effectively confines the peak-to-peak difference in pseudorange observations between master and slave stations to 3.04 meters， while stabilizing the synchronization millisecond pulse delay within 8 nanoseconds. This results validate the validity and reliability of the proposed architecture in low-cost， clock-independent networked environments.关键词：ground-based navigation system;tracking loop;coherent transponding19|13|0更新时间：2026-06-15
- 摘要：Geomagnetic navigation has advantages of autonomy， passivity and strong concealment. However， traditional geomagnetic matching methods rely on the accurate construction of geomagnetic maps， which restricts their application in overseas， ocean and other scenarios where precise geomagnetic information is difficult to obtain. To address this problem， this paper proposed a biomimetic geomagnetic navigation algorithm without a prior geomagnetic map， which integrated the evolutionary algorithm with the improved sparrow search algorithm to achieve autonomous navigation. Three improvements were made to the traditional sparrow search algorithm： firstly， the Tent chaotic map was adopted to generate the initial heading angle population， whose four indicators including grid number variance were all superior to those of the random generation method， improving the spatial coverage uniformity of initial solutions； secondly， the update strategy of explorers’ position was improved by introducing the display mechanism of the peafowl optimization algorithm （with a display probability of 0.4 and an initial learning rate of 0.3） and adding a random disturbance term to balance the algorithm’s exploration and exploitation capabilities； thirdly， the elite opposition-based learning mechanism was introduced to generate the opposite solution for the optimal solution and retain the better one， avoiding the algorithm from falling into local optimum. In the navigation process， the three-axis geomagnetic intensity was selected as the operation parameter， and the multi-objective weighted function was used to evaluate the heading angle and guide its update. Simulation experiments verify the effectiveness of the proposed algorithm through Monte Carlo random experiments， with a success rate of 100%， a mean error of 22.010 2 m between the navigation end point and the target point， and an average number of iteration steps of 203. Comparative experiments were carried out with three groups of start and end points with different latitudes， longitudes and altitudes. The results show that the proposed algorithm is significantly superior to the traditional evolutionary algorithm in path straightness and iteration efficiency while maintaining navigation accuracy. Compared with the evolutionary gradient algorithm and its improved version， the proposed algorithm achieves a path straightness of 1.006 7 and a target point error of only 18.91 m， which is significantly better than the comparison algorithms， verifying its superiority.关键词：a priori-free geomagnetic map;geomagnetic navigation;evolutionary algorithm;sparrow algorithm11|13|0更新时间：2026-06-13
- 摘要：To address the issues of limited estimation accuracy and insufficient resolution in Direction of Arrival （DOA） estimation for vector hydrophone arrays under low Signal-to-Noise Ratio and small snapshot conditions in underwater environments， a DOA estimation method for vector hydrophones based on Weighted Sparse Bayesian Learning （WSBL） is proposed.First， a signal reception model for vector hydrophones is constructed based on coprime array theory， effectively expanding the array aperture and enhancing degrees of freedom without increasing the number of physical sensors. Second， an iterative weighted sparsity constraint mechanism is introduced into the Sparse Bayesian Learning framework. This mechanism constructs a diagonal weighting matrix inversely correlated with signal strength based on hyperparameter estimation results. By modifying the signal prior variance with this matrix， the algorithm adaptively penalizes noise directions and focuses on true signal directions during iteration， significantly enhancing the distinction between real signals and noise. Finally， a fast factor maximization method replaces the traditional Expectation-Maximization algorithm to alternately update hyperparameters， directly maximizing the marginal likelihood function via matrix trace operations to reduce computational complexity and accelerate convergence.The proposed WSBL method effectively mitigates noise interference under low SNR conditions through the weighting mechanism and fast hyperparameter solving strategy. Simulation results demonstrate that within the SNR range of -20 dB to 10 dB， and in both single-source and multi-source scenarios， the method exhibits lower Root Mean Square Error， verifying its superior DOA estimation accuracy and robustness compared to traditional algorithms.关键词：coprime array;sparse Bayesian learning;DOA estimation;vector hydrophone13|11|0更新时间：2026-06-13
- 摘要：To address the problems of insufficient feature exploitation and inadequate information fusion in drone radio frequency fingerprint identification， this thesis proposed a multi-path parameter attention fusion network architecture. Using the DroneRF dataset as the research object， RF signals collected in the low-frequency and high-frequency bands were modeled separately， and the original signals were represented simultaneously as statistical features and spectrograms， thereby constructing four input paths： low-frequency statistical features， low-frequency spectrograms， high-frequency statistical features， and high-frequency spectrograms. In the feature extraction stage， the TabNet-SA model was introduced to perform feature selection and deep representation learning for statistical features， while the EffNet-Slim model was adopted to extract discriminative features from spectrograms. In the multi-path feature fusion stage， a parameter attention fusion strategy was designed to perform adaptive weighting through learnable parameters， thereby enhancing the complementarity among features of different modalities and frequency bands and improving the overall feature representation capability. To verify the effectiveness of the proposed method， twelve groups of comparative experiments were conducted， including single-path， dual-path， average-fusion， different fusion-strategy， and backbone-replacement experiments. The classification results on the DroneRF dataset demonstrate average accuracies of 100.00%， 99.70%， and 99.54% in 2-class， 4-class， and 10-class tasks， respectively. This method provides a viable solution for UAV target identification in complex electromagnetic environments.关键词：RF fingerprint identification;drone regulation;multi-path feature extraction;parameter attention fusion;deep learning9|11|0更新时间：2026-06-13
- 摘要：To meet the testing requirements encountered during weapon launch in high-shock environments exceeding 100 000 g， this study investigated overload-resistance technology for a high-shock recorder. To address the problems of device damage and signal acquisition failure under severe shock， an integrated anti-overload scheme combining structural and circuit-level design was proposed. In the structure， a three-level protection architecture based on rigid encapsulation and flexible vibration isolation was developed. The inner shell was made of a high-specific-strength aluminum alloy to reduce inertial loads， while aramid-reinforced composite wiring， and a chip-level underfill process were introduced to improve structural stability and electrical interconnection reliability under high-shock loading. In the circuit， a highly integrated and lightweight dual-board architecture was adopted， together with FPGA-controlled high-speed data acquisition and a refined power management strategy， thereby the stability of signal acquisition in severe shock environments was improved and the low power consumption was maintained. Experimental validation on the XG-L-10000 high-overload platform shows that the recorder successfully captures response data throughout the process from aerodynamic acceleration to static equilibrium under a shock level of nearly 100 000 g， and five stages of dynamic response are identified. After applying a 2 kHz low-pass filter to the raw data， a shock response with a peak acceleration of 98870 g and a pulse width of 31 ms was obtained. The results demonstrate that the proposed design enables data storage and readout under shock conditions approaching 100 000 g， verifies the feasibility of the proposed anti-overload scheme， and provides useful guidance for the design of parameter measurement devices for high-shock environments.关键词：weapon;data recorder;high impact;structural design;data processing12|11|0更新时间：2026-06-13
- 摘要：Deep reinforcement learning （DRL） has shown considerable potential in autonomous driving， yet it still faces challenges such as low learning efficiency， poor action continuity， and difficulty in sim-to-real transfer and deployment. To address these issues， this paper proposed an intelligent driving method that integrated a pre-trained variational autoencoder （VAE）， a long short-term memory （LSTM） network， and the proximal policy optimization （PPO） algorithm， forming an LSTM-PPO framework. The method employed the VAE to extract a 95-dimensional environmental feature vector from semantic segmentation images， which was then fused with a 5-dimensional vehicle state vector as input to the policy network. By adopting a unified encoder-decoder structure and injecting noise during training， zero-shot Sim-to-Real transfer from the CARLA simulator to a physical vehicle was achieved. Experimental results show that during simulation training， LSTM-PPO reduces the cumulative number of collisions from 802 to 208 and accelerates the convergence of trajectory deviation. In real-vehicle tests， the average lateral offset in straight-line driving decreases from 5.436 cm to 2.268 cm， while in full-lap driving， the root-mean-square error of the lateral offset drops from 19.868 cm to 7.356 cm， and the success rate increases from 35.71% to 62.50%. Both simulation and real-world deployment outcomes demonstrate the significant advantages of the proposed method in improving trajectory smoothness， enhancing motion stability， and strengthening deployment robustness.关键词：autonomous driving;deep reinforcement learning;decision-making and control;proximal policy optimization;real-world vehicle deployment10|13|0更新时间：2026-06-13
- 摘要：Current large multimodal models （LMMs） are often constrained in Chinese dense text-image generation and understanding tasks by the scarcity of high-quality datasets that encompass complex layouts and diverse fonts. To address this limitation， we introduced MojiTextCN， a large-scale， multi-scenario multimodal dataset. Moving beyond conventional black-box API concatenation paradigms， we designed an automated data construction pipeline that integrated generative large models with explicit Chinese typesetting rules. By adopting a “synthetic + real”dual-track strategy， combining Vision-Language Models （VLMs） with automated annotation techniques， and incorporating the Table of General Standard Chinese Characters for low-level glyph hard-constraints and multi-stage verification， we effectively ensured glyph accuracy and layout consistency. MojiTextCN comprised four complementary subsets： CleanChar （pure text， approximately 2.01 million images）， PicTextLayout （image-text mixed layouts， approximately 419，000 images）， SlideDoc （real-world presentation slides， approximately 80，000 images）， and SceneTextSynth （synthetic scene text）， scaling up to over 3 million images in total. To comprehensively validate the data quality， we proposed a multi-dimensional cross-evaluation framework. In terms of textual legibility， OCR-based evaluations demonstrate a Character Error Rate （CER） as low as 2.40% on the complex scene subset. Furthermore， models trained on this dataset achieve a remarkably low CER of 0.37% in image super-resolution tasks， reinforcing the necessity of constructing native Chinese corpora to bridge the domain distribution gap between Chinese and English. Additionally， zero-shot layout evaluations leveraging large vision models yield a high score of 4.27 （out of 5.0）. Our benchmarking results also reveal that current mainstream models still suffer from character distortion and layout misalignment in long-text rendering and interleaved document generation tasks. Ultimately， MojiTextCN provides a robust data foundation and evaluation benchmark for enhancing cross-modal generation and understanding within complex Chinese contexts， offering significant value for both academic research and practical applications.关键词：multimodal dataset;Chinese text image;text generation;dense text;cross-modal learning11|12|0更新时间：2026-06-13
- 摘要：To address the issues of a singular search direction and the lack of selectivity in the population update mechanism of the traditional Grey Wolf Optimizer （GWO）， which often lead to premature loss of population diversity and insufficient capability to escape local optima， this paper proposes a dual-population driven GWO that incorporates multiple mutation and dual selection operators. The algorithm adopts a cooperative co-evolution framework with two sub-populations. By integrating differential mutation operators with the position update rules of the traditional GWO， it guides the search directions of the respective sub-populations， thereby enhancing the global exploration capability. Simultaneously， during the environmental selection phase， a generational replacement strategy and a one-to-one greedy competitive mechanism are introduced to select high-quality offspring individuals for population update， improving the algorithm's exploitation ability in potential local optimal regions. Furthermore， based on an external archive of historically eliminated solutions and the differential mutation paradigm， a differential escape operator is constructed. This operator adaptively drives the algorithm to escape potential local optima according to the diversity trend of the searching population. By comparing the proposed algorithm with 12 advanced swarm intelligence algorithms on the CEC2017 benchmark test set， the results show that the proposed algorithm achieves an average improvement of 46.97% in convergence accuracy over seven other advanced GWO variants， and an average improvement of 22.78% in convergence accuracy compared to five other classical swarm intelligence optimization algorithms.关键词：grey wolf optimizer;differential mutation;escape operator;dual selection strategy13|10|0更新时间：2026-06-13
- 摘要：In the detection of defects on the inner surface of gun barrels， challenges such as strong textural interference， low-contrast defects， and complex noise exist， and existing methods still have shortcomings in terms of detection accuracy and other aspects. This paper proposed an improved YOLOv8-R50CBAM detection method. After comparing ResNet50， MobileNetV1， and VGG16， ResNet50 was selected as the backbone network. The core components of this model include： Embedding the CBAM attention mechanism into the backbone network to construct the front-end feature extraction module CRB， which enhanced defect feature responses and suppressed background interference； Introducing a PANet-based bidirectional path aggregation module BPAF in the neck section to strengthen the interaction between high-level semantic and low-level spatial information； Integrating Soft-NMS during the inference stage， and enhancing TTA and confidence temperature scaling calibration during testing to form the detection inference enhancement module ODI， which was used to improve the recall rate of dense defects and the reliability of confidence scores. Experimental results show that the proposed model achieves a precision of 89.3%， an F1-score of 0.858， and an mAP of 85.0% on the gun barrel inner surface defect dataset， with an mAP improvement of 19.53 percentage point over the baseline model. Ablation experiments demonstrate that the CRB and BPAF modules significantly improve the detection and localization of fine defects， while the ODI module enhances the model’s detection capabilities on complex samples and the reliability of output confidence scores. This paper constructs a detection model framework that integrates attention mechanisms， bidirectional multi-scale fusion， and system inference optimization， providing a reference for the automated inspection of gun barrel inner surface. A limitation of this approach is the increased model complexity， and further research is needed to achieve lightweight deployment.关键词：gun barrel defect detection;improved YOLO;convolutional block attention module;soft non-maximum suppression;test-time augmentation362|12|0更新时间：2026-06-13
- 摘要：In this study， we investigate a dynamic evolutionary game model with heterogeneous expectations and nonlinear costs in a Stackelberg duopoly under sequential decision-making， where the leader and follower adopt distinct output expectation strategies while accounting for the prevalent phenomenon of increasing marginal costs in production. Through dynamical analysis， we obtain that there exist a boundary equilibrium and a unique positive equilibrium in the system. Using the Jury criterion， we derive the local asymptotic stability condition of the positive equilibrium and the threshold for period-doubling bifurcation. While the period-doubling bifurcation eventually leads to chaos， stability can be restored to the system by implementing boundary conditions obtained through state control. Finally， numerical simulations on the leader's output adjustment speed demonstrate that the system evolves from stability to chaos via period-doubling bifurcations as the parameter increases， indicating that the leader’s overreaction is a key factor in disrupting inter-firm strategic coordination and triggering market instability. The effectiveness of the control strategy in stabilizing the chaotic system is validated， thereby revealing the evolutionary mechanisms governing firm competition under heterogeneous expectations and nonlinear costs. This work provides a theoretical basis for analyzing and regulating stability within sequential decision-making market structures.关键词：Stackelberg model;period-doubling bifurcation;stability;chaos control9|11|0更新时间：2026-06-13
- 摘要：Motor imagery-based brain-computer interface （MI-BCI） is a cutting-edge technology that can realize information interactior between brain and computer by decoding electroencephalogram（EEG） signals associated with motor intention. However， left-right hand MI tasks exhibit highly overlapping spatial features in EEG signals， reducing signal distinguishability and increasing challenges for decoding accuracy and model generalization. This study focused on the EEG signals of four-class hand motor imagery， and designed an EEG data acquisition paradigm， and performed data preprocessing， and built a convolutional neural network model based on spatio-temporal feature fusion to enhance cross-channel information integration， enabling the capture of more discriminative spatio-temporal features. The results demonstrate that the proposed model improves classification performance on four-class hand motor imagery EEG data from five healthy subjects. The model reaches an average classification accuracy of 90.89% and an average Kappa coefficient of 0.88， with the highest classification accuracy of 98.44%， The model achieves an average classification accuracy of 61.85% and the highest classification accuracy of 85% on the public BCI Competition IV 2a dataset. Ablation experiments with varying proportions of training samples and removal of key frequency bands verifies that the model maintains stable classification performance under conditions of limited samples and missing frequency bands. In addition， compared with mainstream models EEGNet and ATCNet， the overall classification accuracy increases by 3.9 percentage point and 4.1 percentage point， respectively， demonstrating good decoding performance， stability， and strong robustness. However， the model still requires further investigation on larger-scale datasets and real-time EEG decoding， and may have potential applications in human⁃computer interaction and intelligent rehabilitation in the future.关键词：brain-computer interface （BCI）;motor imagery;spatio-temporal features;deep learning8|10|0更新时间：2026-06-13
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Broadband Vibration Energy Harvesting System Based on Complementary Triboelectric Nanogenerators AI导读
摘要：To solve the problems of narrow effective working bandwidth and unstable output voltage widely existing in vibration energy harvesting of traditional Triboelectric Nanogenerators （TENG）， this paper proposed a broadband coupling energy harvesting system based on a complementary contact-separation mechanism. The system utilized a vertically symmetrical double TENG unit and a spring-mass coupling structure. Through the alternating contact and separation of two pairs of TENGs during vibration， the time complementation and smooth superposition of energy output were achieved， thereby significantly broadening the working bandwidth and improving output stability. This paper first established a two-degree-of-freedom spring-mass-damper dynamic model of the system. The describing function method was employed to linearize the collision nonlinearity， and the amplitude-dependent equivalent stiffness and equivalent damping expressions were derived， which revealed the bandwidth expansion mechanism where the resonance frequency shifts to high frequency after collision intervention. Furthermore， the influence of the friction layer spacing on the potential distribution under the vertical contact-separation mode was analyzed through finite element simulation， and the rationality of the theoretical model was verified. On this basis， the controlled variable method was used to systematically explore the influence laws of key parameters such as spring stiffness （250-350 N/m）， mass block mass （50-110 g）， upper TENG initial gap （1-3 mm）， and external excitation acceleration （9-15 m/s²） on the system frequency response and output voltage. Simulation and experimental results show that when the spring stiffness is 300 N/m， the mass is 80 g， and the initial gap of the upper TENG is 1 mm， the system achieves a broadband stable working bandwidth of 11-25 Hz under the excitation of 15 m/s² acceleration， and the peak output voltage reaches a high level. The complementary coupling structure proposed in this study effectively overcomes the shortcomings of strong output pulsatility and long energy blank periods of single-channel TENGs. It provides a simple solution without external control for continuous energy harvesting in low-frequency vibration environments， is suitable for vibration energy recovery of industrial motors and pumps with speeds of 900-500 r/min （corresponding to frequencies of 15-25 Hz）， and enables self-powering for IoT sensor nodes.关键词：triboelectric nanogenerator;vibration energy harvesting;complementary mechanism;broadband;coupling energy harvesting system7|13|0更新时间：2026-06-13 - 摘要：To address the significant performance degradation of the existing focusing frequency selection in the coherent subspace method for direction-of-arrival （DOA） estimation of acoustic array sources under low signal-to-noise ratio （SNR） and multi-target environments， a focusing frequency selection method based on full-frequency-domain eigenvalue distribution is designed to optimize the focusing frequency selection strategy and improve estimation efficiency and accuracy. Eigenvalue decomposition was performed on the covariance matrix of array received signals at each frequency point， and the ratio of the sum of signal eigenvalues to the sum of noise eigenvalues was defined as the signal-noise separation index； frequency points with higher indices were selected as focusing frequencies. For multi-target scenarios， a multi-frequency focusing set matching the number of sources was constructed to fully utilize all frequency component information of broadband signals. In simulation experiments， the proposed method exhibits sharper spatial spectrum peaks， lower sidelobes， and better adjacent angle resolution under low SNR； for multi-source targets， its estimation accuracy is more stable， and the computation time is significantly shorter than that of the optimal focusing frequency method. In experimental validations in complex office and shopping mall environments， compared with the optimal focusing frequency method and the central frequency method， the proposed method reduces the mean absolute error by 10.2% and 36.4%， and the root mean square error by 41.0% and 50.0%， respectively. It not only achieves smaller average errors but also yields more stable results with fewer large-error cases. The proposed focusing frequency selection strategy can fully utilize full-frequency-domain information， effectively balance computation efficiency and accuracy， and is suitable for low-SNR and multi-target broadband acoustic scenarios. However， its computational complexity increases linearly with the number of frequency points， and its dynamic real-time performance needs further improvement.关键词：broadband acoustic estimation;low signal-to-noise ratios;focus frequency;eigenvalue distribution10|6|0更新时间：2026-06-13
- 摘要：At the early stage of outbreak of an infectious disease， particularly a newly emerging disease， non-pharmaceutical interventions play a crucial role in curbing the spread of disease. Compared to long-term or infinite-term issues that the majority of existing work focus on， investigating the optimal implementation of non-pharmaceutical interventions on short-term horizon has greater practical significance. This paper examines a kind of short-term optimal control problems for an SIR model. To reflect the requirement that the disease prevalence must not exceed the capacity of health-care system， the problem incorporates a state constraint. The paper seeks to identify optimal non-pharmaceutical interventions， aimed at maximizing the final size of susceptible individuals. In contrast to traditional approaches， based on prior results， this paper constructs a novel theoretical framework for solving the proposed problem. The optimal solution is proved to be a bang-bang control involving a single switch， more precisely， the interventions are imposed at the maximum intensity during the initial phase， and then lifted completely after an optimal switching point. This control form exhibits good robust performance across varying initial conditions.关键词：optimal control;non-pharmaceutical interventions;bang-bang control;short-term horizon;capacity state constraint12|6|0更新时间：2026-06-13
- 摘要：To address the bottleneck of simultaneously achieving high-speed motion and large-volume droplet manipulation in surface acoustic wave （SAW）-driven droplet technology， this study proposes a novel interdigital electrode structure and enhances acoustic streaming forces through optimization of electrode geometric parameters， thereby significantly improving energy coupling efficiency. The experimental results demonstrate that， during the driving process of droplets with identical volume， the proposed structure achieves driving speed increases of 185%–195% and 33%–37%， respectively， compared to conventional straight and focused interdigital electrodes. The reduced speed fluctuation range indicates significantly improved stability. At a working frequency of 19.2 MHz， the successful actuation of a 10 μL droplet was achieved， with a velocity ranging from 24.04 to 24.92 mm/s， demonstrating a relatively high speed. Furthermore， a dual-droplet fusion experiment was designed to verify the effectiveness of this structure in enabling active droplet approach， interfacial fusion， and stable post-fusion transport， thereby providing technical support manipulation of large-volume droplets under high flow rates and establishes a foundation for applications such as the construction of droplet-scale microreactors and the sequential control of multi-step biochemical reactions， thereby effectively advancing the practical implementation of acoustic microfluidic technology in the fields of biosensing and material synthesis. Traditional electrodes cannot meet both demands simultaneously. This paper takes the surface acoustic wave-driven droplet system as the research object， establishes a sound streaming force model of the interdigital electrode structure based on acoustic theory， and proposes a novel interdigital electrode structure with the goal of simultaneously achieving high-speed motion and large-volume droplet manipulation. However， existing studies have not yet achieved precise manipulation of droplets in three-dimensional space， and the driving efficiency of liquids with different viscosities such as blood and tissue fluid has not been studied. Further exploration of fluids with different dimensions and viscosities is needed to ensure the application of large-volume droplets in a wider range of fields.关键词：microfluidics;surface acoustic wave;high-speed driving;large-volume liquid droplets10|8|0更新时间：2026-06-13
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