bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of cavity crystal defects on the thermal ecomposition mechanism of NTO
Authors: Wang T B , Li L J , Tao Y T , Ning L Y , Jin S H , Cen K , Lu Z Y 
Published: December 2024

Abstract
The impact of cavity crystal defects on the thermal decomposition process of 3-nitro-1,2,4-triazol-5-one (NTO) was examined utilizing the reaction molecular dynamics method. A perfect crystal model of NTO and crystal models with cavity defects at concentrations of 0.78%, 1.17%, 2.34%, 3.13%, and 5.10% were constructed, and the potential energy and product changes in the isothermal mode at 2500 K were calculated. The impact of cavity defects was analyzed for the initial reaction stages, and the thermal decomposition reaction rate of 2500 K was calculated. The results demonstrate that at 2500 K, the complex reaction of NTO is enhanced, with the denitration reaction emerging as the dominant initial reaction type, followed by the ring-breaking reaction, and the proton transfer reaction occurring with a lower frequency. The principal intermediate products were CO2, NO2, HON, etc. The final products included N2, N4, H2O, HO2, and O2. In the range of 0.78% to 2.34% cavity content, the initial chemical reaction rate of NTO exhibited a slowing down trend with the increase of hole concentration. A collapse in the crystal structure accompanied this. Conversely, an acceleration was observed in the initial chemical reaction rate of NTO when the cavity concentration exceeded 2.34%.
Effects of oxidizer on the secondary reaction of aluminum and metal acceleration for CL-20-based aluminized explosive
Authors: Gao Chenyu , Liu Yan , Lyu Zhongjie , Yan Junbo , Bai Fan , Huang Fenglei 
Published: December 2024

Abstract
The addition of oxidizing agents in the explosives could enhance the burning rate and the reaction degree of aluminum powder due to the increase of oxidizing gas content in the detonation products. Therefore, it affects the metal acceleration ability of the explosive. The current study is concerned with investigating the metal acceleration ability of the CL-20-based aluminized explosive containing oxidizer affecting metal shells through standard cylinder tests. The diameter of the cylinder is 50 mm. An all-fiber displacement interferometer system with a photon Doppler velocimeter took into account the continuous measuring of the cylinder wall velocity over time. The detonation velocity was calculated by the velocity jump time interval of the cylinder wall. BKW equation was applied to calculate the detonation pressure. The effects of oxidizer on the ignition time and the reaction degree of aluminum powder were analyzed by replacing aluminum powder with lithium fluoride for comparison. According to the cylinder wall velocity energy source, empirical formula about explosive composition and the cylinder wall kinetic energy was fitted. The results show that CL-20-based aluminized explosive detonation velocity and aluminum content is linearly correlated, and oxidizer-containing explosives detonation velocity can be equivalent to oxidizer-free explosives within a certain margin of error. With the addition of oxidizer, detonation pressure, and the base explosive content no longer show the same increasing and decreasing relationship. When the aluminum content is 5% and 30%, the ignition time of aluminum powder is 4.81μs and 1.66μs earlier respectively. When the aluminum content is 5%, the reaction degree of aluminum powder reaches 1. The aluminum powder reaction rate for oxidizer-containing explosives and oxidizer-free explosives is mutually fast and slow. When the aluminum content is 30%, aluminum powder reaction degree and aluminum powder reaction rate for oxidizer-containing explosives are higher than that of oxidizer-free explosives throughout. Based on the fitted relationship equation, it is predicted that the maximum value of kinetic energy of the cylinder wall is obtained at 10% aluminum powder content with 10% oxidizer.
Investigation of Combustion Properties Optimizing of Composite Modified Double Base Propellant Containing CL-20
Authors: Xu S Y , Yao E G , Pei Q , Zhang Z H , Jiang H Y , Li M , Hao H X , Zhao F Q 
Published: December 2024

Abstract
The effect of combustion catalysts which are several proportions of A-Pb, A-Cu and carbon on the combustion properties of composite modified double base (CMDB) propellant containing hexanitrohexaazaisowurtzitane (CL-20) were investigated by uniform design. The proportion of the three materials is optimized. The result shows that A-Pb, A-Cu and carbon can affect the combustion properties of CL-20-CMDB propellant. The effect of single A-Pb or carbon on the propellant combustion properties is obvious between 2 MPa and 8 MPa. The effect of single A-Cu on the propellant combustion properties is obvious between 14 MPa and 22 MPa. There is positive interactions of carbon with A-Pb or A-Cu between 2 MPa and 4 MPa and A-Pb with A-Cu or carbon are obvious. The calculation shows that the effect on adjusting the combustion properties of CL-20-CMDB propellant when the proportion of A-Pb, A-Cu and carbon is 3/0.8/0.2.
Research on recrystallization technology of CL-20 based on microfluidic
Authors: Zihao Zhang , Siyu Xu , Hanyu Jiang , Jin Yu , Ergang Yao , Yubao Shao , Xi Chen 
Published: December 2024

Abstract
Using microfluidic technology, CL-20 was prepared at different concentrations, flow ratios, and treatment times. The particle size, morphology and crystal form of the samples are characterized. The results show that metastable state β-CL-20(d50 = 1.04 μm) and a narrow particle size distribution is preferentially precipitated at 0.3 g·mL-1 and a flow rate ratio of 1:20, which needs certain treatment time to transform into ε-CL-20. It demands a considerable amount of time to transform CL-20 into ε-CL-20 via standing suspension, and the obtained ε-CL-20 crystal morphology is superior. Stirring can effectively curtail 80% of the time, but the acquired ε-CL-20 crystal morphology is suboptimal. After agitating the suspension for 1 hour and leaving it to stand for 4 hours, the obtained sample is ε-CL-20(d50 = 50.35 μm), and its surface is sleek and defect-free.
PBX Wide temperature range deformation detection applying in-situ photogrammetry
Authors: Rongfang He , Weibin Zhang , Guofang Gao , Taiwen Wu 
Published: December 2024

Abstract
Abnormal environment especially wide temperature range is an important cause of changes in the physical structure of PBX. And has a significant impact on its reliability and safety performance. In order to master the geometric deformation law of PBX in the wide temperature range, a “dual lens” in-situ photogrammetric method for PBX wide temperature range geometric deformation measurement with a “low expansion reference bar” as the measurement reference is proposed. The ultra-low expansion ceramic gauge block is used as the detection object for experimental research, and the feasibility and detection ability of this method for wide temperature range deformation measurement are verified. The experiment shows that the repeatability of point coordinate detection can reach 0.006mm, and the repeatability of different temperature conditions can reach 0.01mm. In situ monitoring was conducted on the corresponding points of PBX within the temperature range of −20 ℃ to 70 ℃. The data showed that deformation was related to the structure and positively correlated with the size of the structure. The size data before and after temperature cycling showed that it was suspected that after experiencing a low temperature environment of −20 ℃, the structural characteristic size increased irreversibly.
Effect of Accelerated Aging on the Dynamic Mechanical Properties of RDX Based Explosives
Authors: Hu X Y , Wang Y X , Tang J J , Qu K P 
Published: December 2024

Abstract
To reveal the effect of accelerated aging on the mechanical properties of RDX based explosives, dynamic compressive experiments under passive confinement were conducted using a split Hopkinson pressure bar system. The stress-strain behavior of passively confined explosives at different strain rates (500/s∼1100/s) and different aging times (0day∼28days) was obtained. The results show that the compressive mechanical properties of RDX based explosives exhibits obvious strain rate hardening effect, especially the yield strength of unaged specimens. With the increase of aging time, the axial stress corresponding to a specified axial strain before yielding increases. The nonlinear relationship between axial yield stress and constraint ratio is established, and the fitting results are in good agreement with the experimental results for both unaged and aged explosives.
The Influence of Liquid Components of GAP Propellant on Its Mechanical Properties
Authors: Yubao Shao , Siyu Zhang Zihao Xu 
Published: December 2024

Abstract
In response to the problem of poor mechanical properties of glycidyl azide polymer (GAP), a branched high molecular weight glycidyl azide polymer (B-GAP) was used as the adhesive to prepare a propellant with a solid component ratio of 78%. The effects of different network modifiers such as PL1, PL2, and PL3 on the mechanical properties of this type of propellant were studied. The results showed that the sample containing both PL1 and PL3 had the highest tensile strength at 0.712 MPa, but the elongation at break decreased to 35.7%; The sample containing only PL3 has the highest elongation at break, which is 73.3%, and the maximum tensile strength is only 0.315MPa. And the propellant containing PL1 has a lower loss factor; Next is PL3; The loss factor containing PL2 is relatively high.
Structure, nonisothermal decomposition kinetics, thermal safety and mechanisms of improving stability and sensitivity of RDX/expanded graphite embedment composite
Authors: Ma X L , Zhang Z , Fan J , Shang F Q , Ma X , Du X C , Tao Y , Zou H M , Lv X J 
Published: December 2024

Abstract
To understand structure, properties and mechanisms of improving safety of RDX/expanded graphite (EG) embedment composite further and promote the application of EG in energetic materials, embedment stability, formability, detonation velocity, thermal stability, thermal safety and microscopic mechanisms of improving stability and sensitivity of the composite were studied in depth as a supplement to our previous work. Embedment stability was good. Formability (charge density of 1.76 gcm−3) and detonation velocity (7577 ms−1) were acceptable considering the content of EG was 13 wt%. Thermal stability and safety were proved to be improved by kinetics parameters and self-accelerating decomposition temperature. The former was obtained by forty-one kinds of kinetics model functions and six kinetics equations from nonisothermal thermolysis process of RDX. Molecular dynamics were employed to understand microscopic mechanisms for improving safety. Results showed that after being embedded in EG, strength and number of intermolecular forces in RDX crystal increased by 5.45 % and 14.38 %, and N-NO2 maximum bond length of RDX molecule was shorted from 1.60 to 1.56 Å indicating a stronger intermolecular interaction and a safer trigger bond. All these results suggested that RDX/EG embedment composite was a more stable and insensitive system with a certain practical value.
Thermal performance, mechanical sensitivity and low speed impact ignition characteristics of PTFE based aluminum alloy active materials
Authors: Yuan Junming , Wang Nan , Huang Runsheng , Zhou Hanpeng 
Published: December 2024

Abstract
To solve the problems of low energy release efficiency, slow reaction rate, and long ignition response time of Al/PTFE, the idea of introducing aluminum zirconium alloy powder instead of traditional Al powder is proposed in this paper. By utilizing its high calorific value, high enthalpy value, and high activity, the reaction rate and energy of PTFE based aluminum alloy active materials are promoted and enhanced, which ultimately improved and enhanced the energy release efficiency. Aluminium zirconium nickel based active materials were developed using aluminum zirconium alloy powder, and their thermal properties and mechanical sensitivity were tested. The temperature isostatic pressing preparation process based on prefabricated column was also explored. The research results indicate that the Al/Zr/Ni/PTFE formula has a higher exothermic value when Al reacts with PTFE, and it triggers a reaction in the Al/Zr/Ni alloy powder during the reaction stage; The addition of aluminum zirconium alloy powder reduces the impact and friction sensitivity of Al/PTFE materials, with Al/Zr/Ni/PTFE aluminum alloy active materials showing a slight improvement; The ignition response and energy release characteristics of Al/Zr/Ni/PTFE aluminum alloy active materials under hammer impact are significantly improved compared to Al/PTFE. Therefore, the aluminum zirconium nickel based active material system is one of the important research directions in the future.
Research on BEVFormer-based Underwater Object Detection and Localization Model Trained with Migrated Dataset
Authors: Liu Xing , He Yuan , Wang Hancheng , Huang Yu , Chen Chulun , Pan Xuchao , Jiao Junjie , Fang Zhong , He Yong 
Published: December 2024

Abstract
The complexity and variability of the underwater environment have presented a significant technical challenge in the detection and localization of underwater object. In this paper, an underwater object detection and localization method based on the BEVFormer model is presented and experimentally verified for effectiveness. The BEVFormer model incorporates spatial cross-attention and temporal self-attention, leveraging information from both temporal and spatial scales to enhance robustness. The Generative Adversarial Network CycleGAN was employed to generate the underwater dataset U-nuScenes, based on the nuScenes dataset. Results show that the method presented in this paper achieved 24% mAP and 0.35 NDS on U-nuScenes under the condition of utilizing only visual information.
Object Detection Based on Edge Enhanced YOLOv5
Authors: Nie Hui , Ning Yan , Liu Zhentao , Ma Long , Zhang Ruolan 
Published: December 2024

Abstract
In order to address issues that arise in complex scenarios, an edge-enhanced YOLOv5 algorithm is proposed. The fusion of edge features with original feature maps serves to enhance the accuracy of the detection process. The algorithm employs Sobel and Canny operators for edge extraction, integrating these with low-level feature maps through addition and concatenation. Testing in urban and desert settings demonstrated that the enhanced models exhibited superior accuracy and a reduction in false and missed detection compared to the original YOLOv5. This methodology has the potential to enhance target detection performance in complex environments.
Fast Implementation of Image Preprocessing for SAR Scene Matching Guidance
Authors: Chen Shuailin , Nie Hui , Chen Jinyu , Dang Yuanjie , Zhang Zhaoming , Lang Haowen 
Published: December 2024

Abstract
The design of SAR scene matching guidance scheme and the hardware allocation of algorithm module are discussed in this paper. Aiming at the requirement of SAR image preprocessing module, a fast robust feature extraction preprocessing method based on FPGA is designed, and the fast implementation of Gabor filter and wavelet transform is completed. Through the hardware-in-the-loop simulation module test and experimental verification, the FPGA-based pre-processing fast implementation is about 60 times shorter than the DSP processing time, and the results of FPGA, DSP and digital simulation in the hardware-in-the-loop simulation process are consistent. The proposed method not only shortens the processing time of scene matching guidance system, but also ensures the accuracy of SAR image matching.
Simulation and testing analysis of the vibration characteristics of the panoramic sight platform during the driving of a certain tank
Authors: Xingwang Liang , Xiaobing Pang , Weiliang Yuan , Jie Li , Yunrui Wan , Yanfei Su , Qiong Hou 
Published: December 2024

Abstract
To study the vibration characteristics of the panoramic sight platform during the driving of a certain tank, the vibration transmission path of the tank was analyzed, modal simulations were performed on the turret, the carrier platform of the panoramic sight platform, the vibration characteristics of the panoramic sight platform during the driving of tank under different working conditions were tested. The results showed that the vibration modes of the turret were located at the location of panoramic sight platform in the third, sixth, and eighth modes, with natural frequencies of 52.439 Hz, 65.012 Hz, and 87.064 Hz, the main response frequency of each structural component of the panoramic sight platform ranged from 46.5 Hz to 52.5 Hz, which was consistent with the main excitation frequency of the turret and the simulated natural frequency. Therefore, resonance was prone to occur in the panoramic sight platform. The simulation and test results have certain engineering guidance significance for the design and overall layout research of tank panoramic sight platform.
Dynamic response analysis of missile-sled separation in warhead rocket sled test
Authors: Yang Zhen , Yang Yang , Fan Kun 
Published: December 2024

Abstract
The warhead’s attitude upon hitting the target stands as a pivotal factor influencing its dynamic damage effect. This paper addresses the issue of interference posed by the sled and separation device on the warhead’s attack angle during endpoint effect rocket sled tests. Employing an impact dynamics analysis method, we simulate the dynamic response of the missile-sled separation process. Four models are devised, combining two types of rocket sled structures and two variations of arc rail devices with distinct parameters. Comparative analysis is conducted on the sled’s separation distance, the warhead’s attitude, and the sled’s stress. We optimize the rocket sled structure to ensure unhindered separation of the warhead and the sled, followed by verification tests. Analysis reveals that a small curvature radius and insufficient sled stiffness lead to structural failure. Consequently, the sled interferes with the warhead, impacting the target’s attack angle. To address this, we introduce a middle snap ring and slipper to reinforce the sled, along with an increased curvature radius. These two enhancement measures effectively resolve the separation interference issue between the sled and the projectile. The attack angle shift from −0.5° to 1.1° in two sled tests, thus fulfilling the experimental requirements.
Explosion impact dynamics diagnosis of protective structures based on optical coherence velocimetry technology
Authors: Shi Y X , Peng Y C , Xing Y D , Wang L Y , Huang X F 
Published: December 2024

Abstract
The dynamic response of protective structures under explosive conditions is an important criterion for evaluating structural protection. Obtaining the instantaneous response speed and displacement of specific parts inside the protective structure under strong impact conditions is a key and difficult point in evaluating the impact effect and safety of protective structures.. Aiming at the shortcomings of traditional measurement methods with large errors and poor anti-interference ability, optical coherence measurement method is introduced. A multi-channel photonic Doppler velocimetry system and an inertial slider-type displacement sensor are designed to achieve horizontal dynamic displacement without relying on external static references. Numerical simulation technology is also used to simulate the process of shock wave action. The measurement results show that there are plastic and elastic deformations in the protective structure under this explosive shock condition, with maximum plastic deformation of 6.5 mm and peak speed of 2.83 m/s. The peak value of the first axial velocity wave obtained by simulation is close to the measured value, which verifies the accuracy of the simulation method to a certain extent. However, there are still some differences indicating that the model parameters still need to be continuously optimized. This system has the advantages of long measurement time, strong anti-electromagnetic interference, and a large range of speed and displacement. It can grasp the velocity and displacement response and attenuation law of the protective structure, providing an important reference for evaluating impact effects and protective structure safety.
Numerical study on consecutive water entries of twin spheres under the influence of current
Authors: Wang X , Lyu X 
Published: December 2024

Abstract
The consecutive water entries of projectiles into the water flow involve complex flow field and motion interference phenomena, resulting in unpredictable projectile trajectories. In this paper, a three-dimensional numerical model with six-degree-of-freedom technology is conducted to investigate the parallel water entry of two spheres. The explicit volume of fluid model is adopted to track the air-water interface, and the shear-stress transport k-ω model is used to delineate the turbulence structures. The multi-overset technology is employed to track the independent movement of the two spheres during water entry. The numerical results evaluate the effect of water flow on the consecutive water entry process in terms of cavity dynamics, flow field evolution, and hydrodynamic characteristics. During the upstream water entry, the flow-induced cavity tilting reduces the peak lateral force coefficient of the trailing sphere by about 28.9%. However, the constant impact of the current leads to an increase in the trajectory deviation by about 53.2%. The attractive force exerted by the inclined cavity on the downstream side sphere provides sufficient attraction to deflect it toward the upstream side by overcoming the lateral force generated by the water flow. The variation of the peak lateral force coefficient is close to 200%. However, this deflection disappears upon increasing the lateral distance of two spheres.