Issue 01, 2026
DL-SESTR:a deep learning-based semantic encoding method for synthetic trajectory reconstruction
LI Tongxin;ZHANG Jing;HU Haoze;ZENG Zuanyang;LIAO Huaxiong;Background knowledge attacks pose serious threats to trajectory privacy by exploiting prior knowledge to infer user behavior patterns. Existing trajectory reconstruction methods, however, suffer from two major limitations.First, they fail to address semantic location information leakage effectively, and their deep learning models lack optimization under noisy conditions, leading to inadequate reconstruction accuracy and weak semantic extraction. Second,their poor generalization ability hinders efficient reconstruction across heterogeneous datasets, thereby limiting the comprehensiveness of privacy protection. To address these limitations, this study proposes a deep learning-based semantic encoding method for synthetic trajectory reconstruction(DL-SESTR), a false trajectory reconstruction method based on semantic information encoding. The method integrates a bidirectional long short-term memory network(BiLSTM) with an attention mechanism to capture spatiotemporal dependencies and dynamically identify key trajectory points, thereby improving noise resistance. It also introduces a point-of-interest semantic annotation algorithm(PSA)that matches multi-source point-of-interest(POI) data efficiently to enhance annotation performance. Furthermore, a hierarchical semantic encoding algorithm based on the Hasse diagram(HDSE) is proposed, constructing a semantic sensitivity weight model to distinguish high-priority semantic information from noise. Experiments on the T-Drive and GeoLife datasets evaluated model performance across dense and sparse regions, varying privacy budgets, and dayand-night scenarios. DL-SESTR consistently outperforms baseline methods in balancing privacy protection and data utility: Hausdorff distance is reduced by 0.3%, dynamic time warping(DTW) efficiency improves by 1.2 times,and root mean square(RMS) improves by 1.18 times. Under a low privacy budget( ε = 0.01), the method still achieves a 95% Euclidean distance reduction rate, demonstrating strong robustness and generalization ability.
Vehicle scheduling optimization at unsignalized intersection based on Petri net and improved black-winged kite algorithm
CAO Meng;ZHANG Funa;JIANG Xinyu;HUANG Cheng;LIU Huixia;ZHANG Sihan;SUN Wenqiang;To meet the demand for efficient vehicle passage at unsignalized intersections in intelligent connected environments, this study proposes a new vehicle scheduling optimization method for unsignalized intersections based on a Petri net model, a deadlock avoidance strategy, and an improved black-winged kite algorithm(BKA), with the objective of minimizing the maximum vehicle passing time. The proposed method first encodes the vehicle passing sequences and establishes a mapping between vehicle numbers and BKA individuals. Then, a real-time online deadlock detection and repair strategy is applied to each individual to ensure control feasibility. Furthermore, two improvement strategies are developed for the BKA, the improved Circle chaotic mapping and the Levy flight strategy, to improve the algorithm′s solving speed and solution accuracy. Finally, experiments are conducted on a two-way four-lane intersection under multiple typical scenarios, and comparisons are made between the improved BKA, the original BKA, and the genetic algorithm to verify the significant advantage of the proposed method in minimizing the maximum passing time. Statistical analysis further demonstrates that the proposed method achieves the best performance in terms of convergence speed, stability, and optimization effectiveness. The experimental results show that the improved BKA exhibits strong optimization search capability in solving the vehicle scheduling optimization problem at unsignalized intersections.
Mobile robots path planning based on improved ant colony algorithm
YUAN Junhui;WANG Xiaodong;MA Yingcang;Path planning for mobile robots is considered one of the fundamental research areas in robotics. It involves determining an optimal, collision-free path from a start point to a target based on the assigned task and environmental perception. To address the limitations of the standard ant colony optimization(ACO) algorithm, including slow convergence, redundant paths, and susceptibility to local optima, this study proposes an improved ACO algorithm. Firstly,goal-oriented Euclidean and Chebyshev distances are fused to enhance early-stage search efficiency, and a normal distribution(Gaussian distribution) is introduced into the heuristic function to improve path search precision. Secondly,a reward-penalty strategy is incorporated into the pheromone update mechanism to reinforce the influence of highquality paths and accelerate convergence. Thirdly, an adaptive pheromone evaporation factor is applied to dynamically adjust the search behavior, thereby enhancing global exploration and reducing the risk of becoming trapped in local optima. Finally, a pruning strategy is employed to reduce the number of turns and shorten the overall path length. Comparative simulation experiments with other algorithms in both two-dimensional and three-dimensional environments demonstrate that the proposed algorithm not only yields shorter paths but also exhibits higher search efficiency in terms of running time.
Preparation and evaluation of X-ray shielding performance of Bi_2O3/TPU/W-coated yarn fabric
ZHOU Rui;ZHANG Feiyan;CHEN Huajie;ZHANG Yiming;YAO Lirong;To investigate the preparation process and X-ray shielding performance of bismuth oxide/polyurethane/tungsten wire(Bi_2O3/TPU/W) sheathed yarn fabrics, using a spinning solution of polyurethane(TPU) and bismuth oxide(Bi_2O3) with tungsten wire(W) as the core layer, Bi_2O3/TPU/W sheathed yarn was fabricated via core-sheath composite electrospinning technology and subsequently woven into a plain-woven fabric. The effects of Bi2 O3 addition on the surface morphology, chemical composition, mechanical properties, air permeability, and X-ray shielding performance of the nanofiber membrane were investigated. The results indicated that: 1) when the Bi2 O3 addition was 75%,the Bi_2O3/TPU fiber membrane exhibited uniform particle distribution and well-defined morphology; 2) when the diameter of the Bi_2O3/TPU/W sheathed yarn was 0.7 mm, the yarn structure was stable with satisfactory tensile strength.The prepared Bi_2O3/TPU/W sheathed yarn fabric, with a thickness of 1.4 mm, achieved an air permeability of 1 220 mm/s,a moisture vapor transmission rate of 7 040 g/(m2·24 h), and an X-ray shielding lead equivalent of 0.27 mmPb at an incident energy of 83 keV.
Fabrication and electromagnetic wave absorption properties of flake carbonyl iron/polyester fiber reinforced composites
JIN Xinyi;GUO Nannan;FENG Jingang;HE Hengxin;ZHU Licheng;PANG Tianwen;GU Wenyan;Flake carbonyl iron powder(CIP) is a typical magnetic-loss electromagnetic wave absorber, but its high density limits practical application. In this study, CIP was compounded with waterborne polyurethane( PU) and polyester fiber(PET) to prepare CIP/PET/PU composites, and their performance was systematically investigated. Two CIP sizes were each dispersed at different mass ratios into PU solutions to form impregnation solutions, into which PET fibers were subsequently immersed to yield CIP/PET/PU. Characterization of the microstructure, microwave absorption properties, and mechanical performance revealed distinct differences between the front and back sides of the composite. The cross-section exhibited a gradient distribution of CIP, transitioning from a dense concentration at the back side to a sparse distribution at the front side, with larger CIP particles being more prone to forming a dense structure on the back side. The microwave absorption performance of the back side was significantly superior to that of the front side. For composites containing larger CIP at a mass ratio of m(CIP)∶m(PU) = 1.5, the minimum reflection loss reached-25 d B at 18 GHz. Effective absorption was still achieved at a low mass ratio of m(CIP)∶m(PU) = 0.15, indicating promising potential for lightweight composites. Regarding mechanical properties, composites with smaller CIP at m(CIP)∶m(PU) = 0.015 showed mechanical performance slightly higher than or comparable to that of the CIP-free composite. Similarly, composites with larger CIP at m(CIP)∶m(PU) = 1.5 exhibited slightly better mechanical properties than the CIP-free composite. However, all other samples showed inferior mechanical performance compared with the CIP-free composite.
Preparation and structural control of flexible alumina-based nanofiber membranes
ZHANG Mengjiao;LI Wenzhe;WANG Wenqiang;ZHANG Hanwen;FU Qiuxia;GE Jianlong;SHAN Haoru;Alumina(Al_2O3) nanofiber membranes are promising high-temperature thermal insulation materials with broad applications in aerospace, firefighting, and rescue operations. However, rapid grain growth during phase transformation tends to cause brittle cracking, limiting their practical use. Element doping is an effective strategy to suppress excessive grain growth and improve the high-temperature flexibility of Al_2O3-based fiber membranes. In this study,two-dimensional Al_2O3-based nanofiber membranes with good flexibility were fabricated by combining sol-gel and electrospinning techniques with the incorporation of Zr and Si as dopants. Scanning electron microscopy(SEM), transmission electron microscopy(TEM), and X-ray diffraction(XRD) were employed to investigate the effects of dopant type, doping ratio, and calcination temperature on fiber morphology and crystal structure. Tensile strength and flexural performance were also systematically characterized. The results show that Zr doping significantly reduces grain size and improves flexibility. However, calcination at 1 400 °C leads to noticeable grain coarsening and a marked decline in flexibility. In contrast, when Si is used as the dopant at an Al ∶Si molar ratio of 6 ∶1, the resulting Al2 O3-SiO2 nanofiber membrane exhibits uniform morphology and a stable mullite phase. This membrane retains good flexibility after calcination at 1 400 ℃. After calcination at 1 000 ℃, it achieves a tensile strength of 1.03 MPa, maintains a flexural stiffness of 70 mN after 500 bending cycles, and shows a low room-temperature thermal conductivity of0.029 9 W/(m·K), demonstrating excellent overall performance.
Research on the antibacterial modification and properties of melt blown materials using DEHMA
ZHU Xia;ZENG Qianru;GUAN Kehan;XU Haibo;CHEN Guangfu;ZHANG Haifeng;Melt-blown air filtration materials can capture harmful microorganisms but risk releasing them as secondary pollutants. To address this problem, polypropylene(PP) melt-blown material was used as a substrate, onto which the quaternary ammonium salt antibacterial agent 2-(dimethylamino)ethyl methacrylate hexadecyl bromide(DEHMA),acrylic acid(AA), and silver(Ag) ions were sequentially grafted via chemical grafting, yielding two antibacterial materials: PP-DEHMA-AA and PP-DEHMA-AA-Ag. Successful grafting was confirmed by scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS), Fourier transform infrared spectroscopy(FTIR), and X-ray photoelectron spectroscopy(XPS). After modification, distinct particles appeared on the material surface, and Br and Ag elements were detected by EDS. The modification did not significantly alter the crystalline structure of the PP substrate, as its characteristic diffraction peaks remained at 14.1°, 17.9°, and 22.0°. Antibacterial tests showed that both modified materials exhibited excellent efficacy against Escherichia coli( E. coli) and Staphylococcus aureus(S. aureus). PP-DEHMA-AA achieved antibacterial rates of 98.95% and 99.15% against the two bacteria, respectively. PP-DEHMA-AA-Ag further improved these rates to 99.43% and 99.69%, and showed a faster bactericidal rate against S. aureus. This enhancement is attributed to a synergistic effect: DEHMA disrupts bacterial cell membranes via electrostatic interactions, while silver ions penetrate cells and impair enzyme activity. This study offers a viable approach to developing high-efficiency antibacterial air filtration materials.
Preparation and piezoelectric properties of bacterial cellulose/chitosan/barium titanate aerogels
WANG Yijie;SU Xin;SUN Yingying;FU Yijun;ZHANG Wei;LI Dawei;To prepare piezoelectric sensors with good mechanical and piezoelectric properties, BC/CS and BC/CS/BT-OH composite aerogels were fabricated using bacterial cellulose(BC) and chitosan(CS) as the aerogel matrix and hydroxylated barium titanate nanoparticles(BT-OH) as the piezoelectric material via freeze-drying. The surface morpho-logy, chemical structure, mechanical properties, and piezoelectric properties of the composite aerogels were characte-rized by scanning electron microscopy(SEM), Fourier transform infrared spectroscopy(FTIR), X-ray diffraction(XRD), a universal testing machine, and an electrometer. The results showed that the incorporation of BT-OH into the BC/CS composite aerogel rendered the internal structure more porous and the surface microstructure rougher, with BT-OH nanoparticles uniformly distributed throughout the composite. FTIR and XRD analyses confirmed the successful hydroxylation of BT nanoparticles. When the BT-OH mass fraction was 2.0%, the BC/CS/BT-OH composite aerogel exhibited optimal mechanical performance, achieving a compressive stress of 77.69 kPa at 70% strain, which was1.93 times that of the BC/CS composite aerogel under the same strain condition, demonstrating excellent fatigue resistance. The introduction of BT-OH also enhanced the piezoelectric output. At a BT-OH mass fraction of 2.0%, the output voltage and current of the BC/CS/BT-OH aerogel both reached 3.56 times those of the BC/CS composite aerogel.
Research progress in preparation process of fiber-based carbon aerogels
HUANG Zhijie;YU Caijiao;SHAN Haoru;LIU Qixia;CHEN Tianye;GE Jianlong;Carbon aerogels have attracted considerable attention due to their high specific surface area, ultra-high porosity, and low density. With advances in fiber materials research and nanotechnology, fiber-based carbon aerogels have demonstrated superior tensile strength, compressive resistance, and fatigue resistance compared to conventional carbon aerogels, broadening both the preparation routes and functional applications of this material family. This review classifies fiber-based carbon aerogels according to their preparation methods, and systematically summarizes the preparation principles, methods, and research progress of four categories: direct carbonization, sol-gel, electrospinning,and three-dimensional(3D) printing. The key factors influencing each preparation method and their roles in regulating the functional performance of the resulting materials are also analyzed. Finally, future development directions for fiber-based carbon aerogels are discussed. Guided by the concept of green research and development, this review proposes a research framework centered on process efficiency, product sustainability, and multidisciplinary functional integration.
Succession characteristics and ecological significance of Cladocera assemblages in Bosten Lake over the past century
CHENG Longjuan;ZHANG Jiali;XUE Bin;JIANG Qingfeng;WAN Dejun;NING Dongliang;YANG Shuyi;ZHANG Wen;As essential primary consumers and secondary producers in freshwater lake ecosystems, the composition and abundance of Cladocera directly reflect the status of lake ecosystems. Bosten Lake is one of the most important freshwater lakes in northwestern China. This study analyzes the zooplankton Cladocera subfossils in a sediment core from the central point of Bosten Lake, combined with measurements of210Pb and137Cs activity to establish an accurate chronological sequence for the core. The study reveals the succession characteristics and ecological significance of the Cladocera population structure in Bosten Lake over the past century. The results show that 17 genera and 25 species of Cladocera were identified in the sediments of the lake. The dominant species include Bosmina spp., Monospilus dispar,Alona spp., and Chydorus sphaericus s.l. Over the past century, the population structure and diversity of Cladocera in Bosten Lake exhibited notable phase changes. Prior to the 1867, the total abundance of Cladocera was low, with dominance by littoral species and high diversity indices, indicating that the lake was in a low water-level, grassdominated environment. From the 1884-1909, the total abundance of Cladocera increased rapidly, reaching its highest level in the core, with dominant species still being littoral types, but with an increase in the concentration of planktonic Bosmina spp. and rising diversity, suggesting increased water levels and nutrient levels in the lake. From the 1909-1963, Cladocera abundance and diversity levels decreased, with the dominant species shifting from Monospilus dispar to Chydorus sphaericus s.l. This indicates the increased nutrient levels and turbidity in the lake.Since the 1963, the total abundance of Cladocera has rapidly increased, with Bosmina spp. becoming the dominant species and further declines in diversity, reflecting significant degradation of the lake′ s water quality. The planktonic-to-littoral species ratio( P/L) significantly increased, indicating rising water levels in the lake. This study provides effective biological indicators to support the reconstruction of freshwater lake ecosystems in arid and semiarid regions.