新型舰炮使用测速雷达后观测距离偏差射击校正方法

针对测速雷达精确校正初速后的观测距离偏差校正方法进行研究,建立不同校正方法校正量计算模型,对比分析不同校正方法校正精度,得出了使用测速雷达精确校正初速后观测距离偏差应采用折合空气密度校正精度高的结论,为中大口径舰炮部队作战与训练和装备的研制改进提供依据。     

Study of nano-nitramine explosives: preparation,sensitivity and application

Nano-nitramine explosives (RDX, HMX, CL-20) are produced on a bi-directional grinding mill. The scanning electron microscope (SEM) observations show that the prepared particles are semi-spherical, and the narrow size distributions are characterized using the laser particle size analyzer. Compared with the micron-sized samples, the nano-products show obvious decrease in friction and impact sensitivities. In the case of shock sensitivities, nano-products have lower values by 59.9% (RDX), 56.4% (HMX), and 58.1% (CL-20), respectively. When nano-RDX and nano-HMX are used in plastic bonded explosives (PBX) as alternative materials of micron-sized particles, their shock sensitivities are significantly decreased by 24.5% (RDX) and 22.9% (HMX), and their detonation velocities are increased by about 1.7%. Therefore, it is expected to promote the application of nano-nitramine explosives in PBXs and composite modified double-based propellants (CMDBs) so that some of their properties would be improved.     

Long-rod penetration: the transition zone between rigid and hydrodynamic penetration modes

Long-rod penetration in a wide range of velocity means that the initial impact velocity varies in a range from tens of meters per second to several kilometers per second. The long rods maintain rigid state when the impact velocity is low, the nose of rod deforms and even is blunted when the velocity gets higher, and the nose erodes and fails to lead to the consumption of long projectile when the velocity is very high due to instantaneous high pressure. That is, from low velocity to high velocity, the projectile undergoes rigid rods, deforming non-erosive rods, and erosive rods. Because of the complicated changes of the projectile, no well-established theoretical model and numerical simulation have been used to study the transition zone. Based on the analysis of penetration behavior in the transition zone, a phenomenological model to describe target resistance and a formula to calculate penetration depth in transition zone are proposed, and a method to obtain the boundary velocity of transition zone is determined. A combined theoretical analysis model for three response regions is built by analyzing the characteristics in these regions. The penetration depth predicted by this combined model is in good agreement with experimental result.     

Theoretical study of an energetic material di-1H-1,3,4-triazole derivatives

Computations by density functional theory (DFT) method are performed on a series of di-1H-1,3,4-triazole derivatives with different substituents and linkages. The heat of formation (HOF) is predicted by the designed isodesmic reactions. The predicted results reveal that –N₃ and –NN– groups are effective structural units for increasing the HOF values of the di-1H-1,3,4-triazole derivatives. The HOMO–LUMO gap is affected by the substituents and linkage groups. Detonation performance is evaluated using the Kamlet–Jacobs approach based on the calculated density and HOF. The results indicate that –NO₂, –NF₂, –NH–, –NH–NH– and –NN– groups are helpful for enhancing the detonation properties of di-1H-1,3,4-triazole derivatives. The bond dissociation energy and bond order of the weakest bonds are analyzed to investigate their stability. It is observed that the –CH₂–, –CH₂–CH₂– and –CHCH– groups are effective structural units for improving the stabilities of these derivatives. Considering the detonation performance and the stability, five compounds are screened as the potential candidates for high energy density materials.     

Scale-up synthesis and characterization of 2,6-diamino-3,5-dinitropyrazine-1-oxide

2,6-diamino-3,5-dinitropyrazine-1-oxide (ANPZO), as an insensitive high explosive, with a high yield and excellent purity has been prepared at pilot plant scale by an improved method. The synthesized ANPZO is characterized by IR, laser granularity measurement, SEM and HPLC. The particle analysis revealed that the improved method could offer desired product with average particle size of 40 μm and high purity (>98.45%). The experimental parameters exhibited that the detonation velocity of the formulation based on ANPZO was higher than that of the corresponding TATB formulation. The DSC curve showed that the exothermic decomposition of the product occurred at the temperature between 300.5 °C and 360.4 °C. Furthermore, the sensitivity test suggests its safe nature towards mechanical stimulus.     

Analysis on the resistive force in penetration of a rigid projectile

According to the dimensionless formulae of DOP (depth of penetration) of a rigid projectile into different targets, the resistive force which a target exerts on the projectile during the penetration of rigid projectile is theoretically analyzed. In particular, the threshold V_c of impact velocity applicable for the assumption of constant resistive force is formulated through impulse analysis. The various values of V_c corresponding to different pairs of projectile-target are calculated, and the consistency of the relative test data and numerical results is observed.     

收发深度变化对浅海混响的影响研究*

海洋中,由于种种原因可能造成声呐发射深度或接收深度发生变化,针对这一问题,研究了水听器的晃动给混响强度带来的影响.在波束位移射线简正波理论的基础上推导了浅海混响模型,仿真比较了负跃层浅海情况发射深度或接收深度上下变化1m时(小幅度变化)的混响衰减曲线,结果表明发射深度或接收深度上下变化Im时对混响衰减曲线的影响不大.可以认为水听器小幅度晃动时浅海混响相对于声源深度及接收深度是稳定的.     

某型飞机短周期模态特性分析

对纵向短周期模态方程进行了推导和简化,分析了短周期模态的成因和影响的因素,以某型飞机为例计算了本体的短周期模态参数变化规律,分析了其不足,并提出改进方法并进行了计算验证,得到了较好的结果。     

基于测速定轨的一类自适应样条滤波方法

提出了一种测速定轨的实时算法。该方法基于样条表示飞行轨道速度参数 ,在只有多个测速元信息的情况下 ,建立了自适应Kalman滤波递推算法 ,实时给出了较高精度的飞行器轨道参数     

变速箱体声辐射规律

研究了变速箱声源的声辐射规律;论证了坦克变速箱内的故障信息能由箱体的声信号辐射出来。