Journal of Military Science and Technology

Application of the physical optics method to estimate the RCS of a fixed-wing UAV

Tran Nghiep — 2026-08-25

This paper presents a study on the development of a computational model for the radar cross-section (RCS) of a fixed-wing unmanned aerial vehicle (UAV) based on a three-dimensional triangular-mesh representation and the Physical Optics (PO) approximation. The monostatic scattering problem is formulated as a surface integral and discretized over triangular facets of the UAV geometry. The computational algorithm is optimized for parallel processing to reduce computational time across a wide angular domain. The RCS results in both vertical and horizontal planes are presented in polar plots and analyzed in terms of directional scattering characteristics. The results show that the PO model enables rapid estimation of the RCS distribution of fixed-wing UAVs during the preliminary design stage.

Acousto-electric current in graphene under the influence of electromagnetic waves

Quyet Thang Nguyen — 2026-08-25

Two-dimensional graphene has garnered significant interest owing to its unique quantum behaviors stemming from a linear energy dispersion relation, with the acoustic-electric (AE) effect emerging as a key phenomenon driven by charge carrier dynamics under surface acoustic waves (SAW). Classical models based on the Boltzmann kinetic equation, effective at elevated temperatures, fall short in accounting for low-temperature experimental data. This work adopts the quantum kinetic equation approach to analyze the AE current in monolayer graphene subjected to combined SAW and electromagnetic waves (EMW). We derive an analytical formula for the AE current that fully captures the electron-acoustic phonon scattering via the deformation potential mechanism and elucidates SAW's role. Numerical simulations reveal the AE current's nonlinear rise with temperature, alongside sharp declines with increasing material sound velocity and EMW parameters. These trends highlight the potential for precise control of AE current via external stimuli. By advancing from classical to quantum frameworks, this study offers deeper insights into the AE effect's fundamentals in two-dimensional graphene.

Investigation of characteristic thermal signatures of breast tumors using infrared thermography

Nguyen Van Hung — 2026-08-25

Breast cancer remains a primary cause of global cancer-related mortality, necessitating advanced early-stage diagnostic modalities. This study investigates the efficacy of infrared thermography (IRT) coupled with a systematic multi-angle acquisition protocol for characterizing malignant breast thermal signatures. A cohort of 38 patients with biopsy-proven breast cancer was evaluated using a FLUKE infrared system integrated with the BKA-06 thermal stimulation device. Thermographic data were acquired at multiple orientations (0°–180°) to comprehensively map thermal distribution patterns. Quantitative analysis identified significant thermodynamic anomalies, including elevated core temperatures, asymmetric heat dissipation, and heterogeneous isothermal contours. Recorded temperature differentials (DT) between tumor cores and peripheral tissues ranged from 1.2 °F to 1.8 °F. Comparative validation demonstrated high spatial congruence between thermographic “hotspots” and MRI-identified lesions, with histopathological biopsy serving as the definitive reference. Distinct from conventional binary classification approaches, this research systematically analyzes intrinsic thermal characteristics linked to pathological angiogenesis and metabolic hyperactivity. The findings suggest that the proposed IRT framework provides a reliable, non-invasive, and radiation-free adjunctive modality, enhancing the precision of early-stage breast cancer screening and clinical assessment.

A hybrid structural-contextual framework for malicious URL detection based on graph attention networks and knowledge distillation

Hieu Nguyen Trung — 2026-08-25

Malicious URLs are evolving with increasingly sophisticated obfuscation techniques, posing a persistent threat to global cybersecurity. Traditional deep learning methods still struggle to identify the intricate topological characteristics and hidden structural dependencies inherent in URL sequences. This paper proposes a structural-semantic integration framework leveraging Graph Attention Networks and Knowledge Distillation for robust multi-layer malicious URL detection. We conceptualize raw URLs as character-level directed graphs to extract intricate structural patterns, fused with high-level lexical context distilled from a pretrained DistilBERT model. A hybrid loss integrating Kullback-Leibler divergence and Negative Log-Likelihood balances computational efficiency and predictive performance. Experimental results on large-scale, imbalanced datasets show our framework achieves 98.86% accuracy and 98.16% F1-score.

A new approach to semi-supervised fuzzy graph-cut clustering

Anh Vu Nam — 2026-08-25

Traditional feature-based clustering algorithms often fail to capture the geometric structure of data effectively. To address this limitation, this paper proposes a semi-supervised fuzzy graph cut clustering algorithm (SS-FGCC), which integrates anchor-point labels into fuzzy clustering and exploits graph structures to improve clustering quality while reducing computational complexity to linear time. Experiments on six synthetic datasets and five UCI datasets demonstrate that SS-FGCC consistently outperforms RCut, NCut, FCM, FFCAG, FGCC, and CEHM, achieving up to 82.76% accuracy. Moreover, the proposed method remains stable on large-scale datasets where conventional graph cut methods often suffer from memory limitations, making SS-FGCC an efficient and scalable clustering solution.

Green synthesis and surface functionalization of zinc oxide nanoparticles with glutamine/pluronic F127 for enhanced antimicrobial activity

Ngọc Sơn Nguyễn — 2026-08-25

This study presents the stepwise surface functionalization of zinc oxide nanoparticles (ZnO NPs) with glutamine (Gln) and Pluronic F127 block copolymer to develop a highly stable, anti-agglomeration biocidal nanoplatform (ZnO@Gln-F127). Comprehensive characterization via FTIR, TEM, and EDX confirmed the sequential modification, revealing a multi-core and single-shell architecture where Gln firmly coordinates to ZnO and anchors the thick F127 polymer matrix via multiple hydrogen bonds. Thermogravimetric analysis quantitatively verified this structural evolution, recording a significant 41.31% organic mass loss. Overcoming the inherent agglomeration of pristine ZnO, the ZnO@Gln-F127 system exhibited superior, concentration-dependent antimicrobial efficacy against Gram-positive Bacillus subtilis and yeast Saccharomyces cerevisiae. The amphiphilic F127 shell provided exceptional colloidal stability through steric hindrance and enhanced microbial interactions, achieving complete eradication of both strains at 1.0 mg/mL. Ultimately, these findings highlight the immense potential of this hierarchical nanostructure for advanced biomedical applications.

Research on the phlegmatization technology of RDX with oxidized polyethylene wax

Văn Quyên Hoàng — 2026-08-25

In this paper, several factors affecting the preparation of A-IX-1O explosive by a surface modification method in an aqueous emulsion system using oxidized polyethylene wax (OPE wax) dissolved in solvent cyclohexane and octylphenol ethoxylate (Triton X-100) surfactant were investigated. The results showed that replacing oxyzin wax with OPE wax at a dissolution concentration in cyclohexane solvent not exceeding 5% and employing Triton X-100 surfactant at low concentrations not exceeding 0.1 wt.% relative to hexogen (RDX), improves the coating coverage of the OPE wax layer on the surface of RDX particles. As a result, the obtained particles were fine, free-flowing, uniform in size, and free from agglomeration. The A-IX-1O explosive prepared in this study exhibited technical characteristics comparable to those of Russian A-IX-1O explosive, but with significantly lower impact sensitivity.

Study on the synthesis and structural characterization of spinel-structured Co3O4 metal oxide derived from metal-organic framework materials

Dr Bang Nguyen Van — 2026-08-25

Spinel Co₃O₄ materials were successfully synthesized through the thermal decomposition of Co-BTC metal-organic frameworks prepared by hydrothermal and microwave-assisted methods. The structural characteristics and physicochemical properties of the materials were investigated by XRD, EDX, FTIR, SEM, and N₂ adsorption-desorption analyses. XRD and FTIR results confirmed the complete transformation of Co-BTC into pure spinel Co₃O₄with high crystallinity, while EDX analysis indicated the complete removal of organic components after calcination. SEM images revealed that Co-BTC exhibited rod-like crystals, whereas Co₃O₄consisted of near-spherical nanoparticles with sizes of approximately 50-60 nm, forming a porous structure. All samples exhibited mesoporous characteristics with type IV-H3 adsorption isotherms. The Co₃O₄sample derived from the microwave-assisted MOF precursor achieved the highest specific surface area of 80.1 m²/g, which was significantly higher than that of the hydrothermal sample. The microwave-assisted method reduced the synthesis time to 60 min while improving the porous structure and process efficiency in accordance with green chemistry principles.

Epoxy resin K-153A and poly(propylene glycol) diglycidyl ether/graphene oxide polymer composite based for properties enhancement

THU BÙI — 2026-08-25

This article introduces the effects of graphene oxide (GO) content on some properties of a composite based on the blend of epoxy resin K-153A and poly(propylene glycol) diglycidyl ether, the blend is hardened with polyethylene polyamine (PEPA). Epoxy resin K-153A is a product of ED-20 epoxy resin modified with oligomer acrylate of MGF-9 and thiokol. Tensile strength of polymer composite with 1.5 wt% of GO is 86.65 MPa and flexural strength of the polymer composite is 105.56 MPa the values are much higher than that of K-153A/ Poly(propylene glycol) diglycidyl ether blend are 68.42 MPa and 79.56 Mpa, respectively. Thermal oxidation resistance polymer composite also increases in comparison to those of K-153A epoxy resin/ Poly(propylene glycol) diglycidyl ether blend.

Research on the microstructure transformation and mechanical properties of lead alloy layer covering copper electrodes of high-capacity lead-acid batteries upon heat treatment

Doan Minh Cuong — 2026-08-25

The lead alloy layer on the copper electrodes of high-capacity lead-acid batteries is manufactured by gravity casting. In the cast state, the lead alloy layer exhibits a dendritic, unbalanced crystal structure, a high hardness of 27.9 HV, high residual internal stress, and a high resistance of 0.312 ÷ 0.420 mΩ, making it prone to microcracks and unfavourable for the battery. Through heat treatment, including quenching at 220 °C for 60 minutes followed by aging at 110 °C for 7 hours, the cast microstructure transforms into a more balanced, polygonal, axial crystal structure. The hardened phase forms, achieving an optimal hardness of 16.2 HV, and the average resistance is reduced to 0.06 mΩ, making it suitable for the manufacture of high-capacity lead-acid batteries.

Influence of components on the fabrication and ballistic characteristics of MC explosives

Trong Dai Nguyen — 2026-08-25

This paper presents research outcomes regarding the influence of formulation components on the fabrication process and detonation characteristics of MC explosives. Experimental findings indicate that Serezin M75 is an optimal phlegmatizer for the production of MC explosives. The primary components—TNT, RDX, and aluminum (Al) powder—directly dictate the ballistic properties of the composite explosive. A formulation comprising (19 ± 2)% TNT, (57 ± 3)% RDX, and (17 ± 2)% Al yields detonation parameters equivalent to those of foreign reference samples. Specifically, the formulation with a mass ratio of TNT : RDX : Al : Phlegmatizer at 19 : 57 : 17 : 7 exhibits superior technological rheology, consistently achieving a casting density exceeding 1.7 g/cm³.

Study on the formulation of transmission lubricating oil for military motor vehicles

Khánh Ngô — 2026-08-25

This paper presents the formulation and performance evaluation of a compounded transmission oil for military motor vehicles as a replacement for imported TAP-15V oil. The developed oil, formulated from selected base oils and a multifunctional additive package, satisfied all requirements of GOST 23652, with a kinematic viscosity of 14,58 mm²/s at 100 °C, a pour point of -26 °C, and a flash point of 234 °C. Four-ball tests showed improved tribological performance compared with TAP-15V oil, achieving a wear index of 720 N and a weld load of 5508 N. The results demonstrate that the formulated oil is suitable for practical application as an alternative to imported TAP-15V oil.

Study on factors affecting the remediation of DDT-contaminated soil using the Biosoil bio-preparation

Thi Ha Trang Le — 2026-08-25

This study evaluates the remediation potential of the bioproduct Biosoil containing Bacillus subtilis for DDT-contaminated soil and identifies factors affecting treatment efficiency. Two field soil samples with initial DDT concentrations of approximately 80 mg/kg (MĐ-TXL-01) and 120 mg/kg (MĐ-TXL-02), exceeding the limits specified in QCVN 03:2023/BTNMT, were investigated. Experiments were conducted with straw supplementation to improve soil porosity, while the effects of temperature, product dosage, and treatment time were assessed. Isothermal conditions showed higher efficiency; however, variable-temperature conditions were selected for practical application. A 3% product dosage was optimal in terms of both technical performance and cost. DDT concentrations decreased rapidly within the first 5÷20 days, followed by a slower degradation rate. After 20 days of treatment with 3% Biosoil under variable-temperature conditions, MĐ-TXL-01 achieved concentrations below the permissible limit, while MĐ-TXL-02 remained above the threshold. The results demonstrate the potential of Bacillus subtilis-based Biosoil for DDT soil remediation; however, additional measures such as nutrient supplementation, soil turning, or supporting technologies are needed for highly contaminated soils.

Experimental characterization of Inconel 625 powder stream and single track deposited on SS400 steel by direct laser metal deposition

Quoc Tuan Nguyen — 2026-08-25

Directed laser metal deposition (DLMD) offers significant potential for producing high-performance coatings and functional components, yet the effect of powder feed rate on coaxial powder stream stability and its correlation with single-track deposition quality remains insufficiently investigated. This study characterizes the Inconel 625 powder stream using light-sheet imaging and grayscale intensity analysis at feed rates of 5–30 g/min. The powder stream consistently converged at approximately 9 mm below the nozzle exit, independent of feed rate, ensuring stable alignment with the laser beam without adjusting the stand-off distance. The transverse profiles exhibited a Gaussian-like distribution. Based on these findings, single-track deposition on SS400 steel produced stable geometry, a fine cellular-to-columnar dendritic microstructure (primary dendrite arm spacing of 2.2–2.3 μm), uniform microhardness of 206.7–209.5 HV (about 25% higher than the substrate), and no porosity, lack-of-fusion, or solidification cracks. These results establish a direct link between powder stream characteristics and deposition quality, providing practical guidelines for robust DLMD processing of Inconel 625 on carbon steel substrates.

Optimization of a silent mortar baseplate with increased ground contact area

Dr Sy Ngo Tien — 2026-08-25

This study presents a parametric optimization of the outer aluminum baseplate of a silent mortar system to improve ground-contact performance while satisfying mass and structural safety constraints. To preserve the system architecture, only the outer baseplate was redesigned, whereas the inner steel baseplate remained unchanged. FEM-based optimization was performed in ANSYS Mechanical under equivalent static recoil loading to evaluate the effects of key geometric parameters on the Von Mises stress, deformation, and minimum safety factor. The optimized design achieved a mass of 5.9 kg, increased the ground-contact area by 53%, and improved the minimum safety factor by 9.8% compared with the original design. Field firing tests under identical soil conditions further reduced settlement by 44.4% after the first firing round and 40.5% after five consecutive rounds. The proposed design effectively improves ground-support capability without compromising structural integrity or operational mobility.

Static stability analysis of dielectric elastomer

ĐÀO HỒNG HẢI — 2026-08-25

Dielectric elastomers (DEs) are compliant electroactive polymers with high energy density and rapid response, making them attractive for soft actuators. Their operational reliability, however, is limited by electromechanical instability (EMI). This study employs the Kelvin–Voigt Generalized Maxwell (KV-GM) model to evaluate steady-state stability under uniaxial, equibiaxial, and non-equibiaxial pre-stretch conditions. The results demonstrate that pre-stretch configuration strongly affects critical voltage and deformation capacity, and that appropriate pre-stretch can suppress EMI and improve the stable operating range of DE actuators.

Improving buried object localization accuracy in heterogeneous environments using TOA-based IR-UWB and machine learning

Nguyen Thi Huyen — 2026-08-25

This paper proposes a buried-object localization method in heterogeneous environments using time of arrival (TOA)-based IR-UWB radar and machine learning techniques. A propagation model is developed to generate a TOA dataset for buried-object locations under multipath and noisy conditions. To improve TOA estimation, a matched-filtering and adaptive-thresholding (MFAT) technique is proposed to enhance reflected pulse detection at low SNR. The extracted TOA features are then used to train Random Forest (RF), XGBoost, and LightGBM (LGBM) models for object localization. Experimental results show that the proposed LGBM-MFAT approach achieves the best performance, with an MAE of 1.26 cm, an RMSE of 2.37 cm, and an R² value of 0.999. The results demonstrate that combining adaptive TOA processing with gradient-boosting models significantly improves localization accuracy and provides an effective solution for penetrating IR-UWB radar systems operating in heterogeneous environments.

An interference-matched notch filter for narrowband RFI suppression in SAR

Van Anh Tran — 2026-08-25

Narrowband radio-frequency interference (NBI) degrades synthetic aperture radar (SAR) images. Frequency-domain notch filtering is a common countermeasure, but a hard (rectangular) notch trades interference rejection against raised sidelobes, and a fixed apodized (tapered) notch cannot suit emitters of different bandwidth. This paper presents a simple, low-complexity notch whose shape is matched to the measured interference spectrum. Based on the classical Wiener idea, it estimates each emitter’s power spectral density from the averaged SAR range spectrum and applies a parametric minimum-mean-square-error gain whose roll-off follows that emitter; the filter is linear, needs no per-scene tuning, and costs about one spectral multiplication per pulse. On a 2-D SAR simulation with emitters of differing bandwidth it gives the lowest point-target peak sidelobe ratio (PSLR; about −15.1 dB), integrated sidelobe ratio (ISLR; about −7.2 dB) and image normalised mean-square error (NMSE; about −7.0 dB) among a hard notch and a fixed apodized notch. The contribution of this paper lies in the per-emitter spectrum-matched notch design and the comparative evaluation of the proposed method’s effectiveness against other approaches.

Thermal stress analysis of dry-type transformers under short-circuit conditions considering temperature-dependent epoxy properties

Hong Hai Pham — 2026-08-25

Accurate prediction of temperature rise and hotspot formation is critical for the lifetime and safety of cast-resin dry-type transformers. Conventional thermal design methods typically assume constant thermophysical properties for epoxy insulation, neglecting their nonlinear temperature dependence - an oversimplification that can introduce significant errors under severe operating conditions such as short-circuit faults. This study applies a temperature-dependent thermal modeling approach to a 320 kVA, 22/0.4 kV amorphous-core dry-type transformer, employing coupled Finite Element Method (FEM) and Computational Fluid Dynamics (CFD) to simulate the three-dimensional transient temperature field with temperature-dependent thermal conductivity, diffusivity, and specific heat capacity of epoxy insulation. Results show that the high-voltage winding is the most thermally critical region under short-circuit conditions, and that incorporating temperature-dependent material properties yields higher predicted hotspot temperatures and stronger thermal stress concentration compared to conventional constant-property assumptions. These findings highlight the importance of temperature-dependent modeling in transformer thermal design and provide a more reliable basis for structural optimization and safety assessment.

Developing a new mathematical model and evaluation of the effect of parabolic mirror edge rounding on the collimated field quality of an infrared collimator used in single-channel aerial vehicle testing equipment

Huy Tran Quoc — 2026-08-25

Parabolic-mirror infrared (IR) collimators are widely used in single-channel flight vehicle testing to generate quasi-plane-wave radiation fields. However, edge diffraction degrades field uniformity and limits measurement accuracy. This paper presents a mathematical model of an IR collimator with rounded mirror edges to evaluate their influence on the radiation field. The model is formulated using the two-dimensional Helmholtz equation and solved by the boundary integral equation method to determine the induced surface current and the resulting radiation field. Numerical results demonstrate that rounded edges effectively suppress diffraction-induced amplitude ripples and improve field uniformity compared with conventional sharp-edge mirrors. The proposed model provides a theoretical basis for optimizing parabolic IR collimators for high-accuracy flight vehicle testing.

Kinematics of the line of sight angle and image-center deviation of the observatory on the mobile vehicle in terms of affecting speed and attitude

Dr Huy Vu Quoc — 2026-08-25

This paper analyzes the formation of line-of-sight (LOS) interference in EO/IR systems due to carrier movement using a three-coordinate kinematic model and pinhole projection. From the given formulas, the paper clarifies the influence of horizontal velocity and angular deviation on LOS rotation speed and pixel drift. Simulation results show that interference is minimal when the carrier is oriented directly toward the target, but increases significantly when a horizontal velocity component is present, especially during phase changes or maintaining the target at a camera-off position. Based on the obtained kinematic analysis, the paper suggests future LOS stabilization systems. The results obtained provide a useful quantitative basis for the design, operation, and optimization of EO/IR tracking systems under mobile carrier conditions.

Design of an adaptive fuzzy–PID controller for a DC motor-based railway barrier system

Dr Nam Pham Van — 2026-08-25

Railway level crossings require reliable barrier systems to operate safely under changing conditions. In practice, DC motor–driven barriers are influenced by load variations, disturbances, and nonlinear behavior, which can limit the performance of conventional PID control. In this study, an adaptive fuzzy–PID controller is developed, where fuzzy logic adjusts the PID parameters online based on the control error and its rate of change. The system is modeled and tested in MATLAB/Simulink, and then implemented on an STM32 microcontroller for real-time validation. The results show that the proposed controller reduces overshoot from 12.76% to 0.85% and provides a smoother response under load disturbances. A slightly longer settling time is observed, but the system remains stable and well-damped during operation. Experimental tests also show consistent behavior, suggesting that the approach can be applied in practical railway barrier systems.

Synthesis of a hybrid super-twisting and adaptive fractional-order sliding-mode control law for the gimbal seeker ensuring disturbance rejection and high accuracy

Nguyen Vi Thuan — 2026-08-25

This paper investigates the synthesis of an Adaptive Fractional-Order Super-Twisting Sliding Mode Control (AFOSTSMC) law to improve line-of-sight (LOS) stabilization performance for the two-axis gimbal drive system of an electro-optical seeker. The gimbal system has strongly nonlinear dynamics and is affected by angle-dependent varying moments of inertia, cross-coupling between the Yaw and Pitch channels, and uncertain disturbances. The proposed controller combines three techniques: (1) the Caputo fractional-order derivative, which accelerates convergence and smooths the error response; (2) the Super-Twisting Algorithm (STA), which suppresses chattering; and (3) an adaptive mechanism, which automatically tunes the controller gains online to compensate for disturbance components with unknown bounds. System stability is proven using Lyapunov theory and the Mittag-Leffler convergence criterion. Simulation results on a compact drive-system model demonstrate the advantages of the hybrid AFOSTSMC law over Super-Twisting Sliding Mode Control (STSMC) and Adaptive Fractional-Order Sliding Mode Control (AFOSMC) methods.