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High-performance solid propellants are very important for the development of modern weapons. Aside from their high energy and high burning rate, safety performance is regarded as the most important factor that should be considered whenever a new solid propellant recipe is formulated. Therefore, exploring a new type of combustion catalyst that can improve both catalytic activity and reduce the sensitivity of the energetic component is significant. Traditionally, transition metals or metal oxides are used as a combustion catalyst for accelerating the thermal decomposition of energetic components. However, the existing problem of these catalysts is the aggregation of particles accompanied by poor surface area. Coupling metal oxides with graphene is a promising approach to obtain a binary composite with stable structure and large specific surface area. In this work, rod-like and granular Fe2O3 nanoparticles were synthesized using a hydrothermal method. Then, the two as-prepared Fe2O3 nanoparticles were coupled with graphene sheets using an interfacial self-assembly method, which can effectively prevent the aggregation of Fe2O3 particles and simultaneously increase the active sites that participate in the reaction. X-ray diffraction and X-ray photoelectron spectroscopy were used to identify the phase states and chemical compositions of the prepared samples. The morphology and internal structures were further demonstrated through scanning electron microscopy, transmission electron microscopy and nitrogen adsorption-desorption tests. Both phase analysis and structure identification indicate that the prepared Fe2O3/G has high purity and high surface area. The catalytic performance of the prepared Fe2O3 and Fe2O3/G in the thermal decomposition of hexanitrohexaazaisowurtzitane (CL-20) was evaluated based on thermal gravimetric analysis-infrared spectroscopy (TGA-IR) and differential scanning calorimetry (DSC) tests. The non-isothermal decomposition kinetics of CL-20, Fe2O3/CL-20, and Fe2O3/G/CL-20 were further studied by DSC. The results reveal the excellent catalytic activity of Fe2O3/G in the thermal decomposition of CL-20, which is attributed to the presence of abundant pore structure and large surface area. The reaction mechanisms of the exothermic decomposition process of CL-20, Fe2O3/CL-20, and Fe2O3/G/CL-20 were obtained by the logical choice method, and the composites all followed same mechanism function model as CL-20. Through comparison, the rod-like Fe2O3 coupled with graphene was found to have the best catalytic activity in the thermal decomposition of CL-20. Thus, the rod-like Fe2O3 and its Fe2O3/G composite were used to investigate their influence on the impact sensitivity of CL-20 by fall hammer apparatus. The results show that rFe2O3/G can effectively decrease the impact sensitivity of CL-20 compared with pure CL-20 and rFe2O3/CL-20. Therefore, rFe2O3 coupled with graphene not only promotes the thermal decomposition but also improves the safety performance of CL-20. 相似文献
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《中国惯性技术学报》2020,(1)
星敏感器在近地面使用时,由于星光信号容易被强烈的天空背景噪声所淹没,导致其无法在白天正常工作。为了提高星敏感器白天探星的能力,提出了一种星敏感器动态条件下基于姿态关联叠加提高星图信噪比的方法。该方法利用陀螺仪测量出与参考帧相关的每个星图帧之间的姿态变化量,实现不同帧星图之间的平移和旋转变换(即相关变换)。最后,将相关帧星图叠加到一起,使星图信噪比得到■倍增长(n为关联星图的帧数),从而提高全天时星敏感器在白昼条件下的工作能力。仿真结果表明:该方法能够有效地提高星图信噪比,且受惯性器件误差和安装角误差的影响较小,具有较强的可行性。 相似文献
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基于结构的对称性提出了用于三维车辆轨道耦合系统高效随机动力响应分析的虚拟激励方法.车辆采用刚体动力学模型,轨道结构利用三维轨道广义单元建模,车辆与轨道通过线性轮轨关系耦合.采用虚拟激励法将高低、方向和水平三类轨道不平顺转化为一系列筒谐的虚拟不平顺;考虑车辆及轨道结构的对称性,分别推导了耦合系统的对称和反对称凝聚矩阵,提出了用于车辆轨道耦合系统动力响应计算的自由度凝聚方法,将耦合系统的自由度缩减至原来的一半以下,并在此基础上实现了耦合系统随机振动的高效分析.数值算例将本文方法与传统有限元方法进行对比,验证了本文方法的正确性和有效性. 相似文献
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