创新经济欠发达地区农村消防安全模式探究

随着农村经济建设快速发展,农村消防安全工作滞后于经济建设的矛盾日益凸显,火灾呈现出多发势头。就如何创新构筑农村消防安全＂防火墙＂工程模式进行探究,为更好地深入开展社会主义新农村建设提供安全保障。     

思想政治理论课“教研互动”教学模式研究

科研与教学结合是思想政治理论课教学的基本要求,要提高教学质量,就必须树立思想政治理论课教学的科学意识,增大教学中的科研含量。确立教学出题科研解题,教学促进科研,科研反哺教学,教学与科研互动的模式,从而实现思想政治理论课教学与科研良性互动、滚动发展、共同提高的良好态势。     

某共享通讯塔加装天线后结构安全性校核

对某共享通讯铁塔加装天线后结构安全性进行校核,建立了基于不同梁杆单元及节点连接的通讯铁塔空间刚架和混合有限元模型,对其结构动态特性及静力分析结果进行了对比分析,指出两种不同模型的动态特性相差不大,采用刚架模型来复核偏于安全;对通讯塔在加装天线后在风荷载及塔自重作用下结构安全性评估,并对该铁塔底层塔段弦杆中点变形超限的特...     

基于模糊信息论的空中目标识别模型研究

空中目标识别是防空作战辅助决策的关键环节之一。针对目标识别中不确定信息,建立基于模糊信息论的空中目标识别模型。该模型利用模糊信息论中的模糊数,基于贴近度的模糊模式识别对待识空中目标进行初步识别,同时为解决不确定信息本身对目标识别结果稳定性的影响,采用模糊信息熵对目标识别结果修正,从而进一步提高了空中目标识别结果的稳定性和可信度。     

反舰导弹典型攻击模式及运动仿真研究

针对当前反舰导弹的主要特点,研究国外典型反舰导弹的攻击模式和运动仿真模型。采用简化六自由度动力学模型,对其典型航迹进行了模型描述,建立了导弹蛇形机动、比例导引、末端跃升俯冲航迹的动力学仿真模型,并得到了几种典型航迹的仿真结果,为水面舰艇的防空反导作战提供了理论支持。     

逆变器驱动电机系统环路型电机轴承电流的研究

论述了正弦波驱动电机系统中的经典型的轴承电流,讨论了逆变器驱动电机系统中的高频磁通产生的轴承电流,分析了环路型轴承电流产生的机理,并且在实验的基础上,得出了环路型轴承电流与共模耦合电流之间的关系,丰富和完善了电机轴承电流的研究内容.     

基于行小波编码的纹理隐藏三维地形数据算法

讨论利用纹理图像隐藏高程信息来保护三维地形数据的信息隐藏技术。首先提出了改进的基于行小波变换及其编码,在保持地形形状和起伏特征的前提下实现高程数据的极低比特率低存储压缩。通过研究可嵌入隐藏信息的小波系数集合生成方法并结合基于视觉系统(HVS)小波域量化噪声的视觉权重(JND)分析技术,提出了自适应确定信息嵌入强度的方法。由于隐藏过程采用分组密码Rijndael生成单向Hash函数,信息隐藏算法高度安全、可以公开。     

遥测参数数据载荷状态判别集成学习方法

针对载荷单机设备遥测参数维度高、数据量大、存在类别不平衡、无法直观判别单机设备运行情况等问题,考虑到航天任务对可解释性的要求,提出一种基于信息增益参数特征选择和集成学习方法的载荷单机状态快速识别方法。采用统计量性质和信息增益子集搜索方法对遥测数据进行特征筛选降维,通过集成学习模型算法实现载荷单机设备状态的自适应识别分类。所提方法将信息增益的参数分类信息量评价准则和集成学习拟合能力强、类别不平衡下准确率高和抗噪能力强等优点相结合,兼顾模型特征和结果的可解释性,提供了重点参数发现功能。采用科学卫星任务真实载荷遥测参数数据对该方法进行了验证,整体识别准确率高于90%,少数样本亦可准确识别,整体效果可达到在轨任务要求,证明了所提方法的有效性和实用性。     

Recent advances in catalytic combustion of AP-based composite solid propellants

Composite solid propellants (CSPs) have widely been used as main energy source for propelling the rockets in both space and military applications. Internal ballistic parameters of rockets like characteristic exhaust velocity, specific impulse, thrust, burning rate etc., are measured to assess and control the performance of rocket motors. The burn rate of solid propellants has been considered as most vital parameter for design of solid rocket motors to meet specific mission requirements. The burning rate of solid propellants can be tailored by using different constituents, extent of oxidizer loading and its particle size and more commonly by incorporating suitable combustion catalysts. Various metal oxides (MOs), complexes, metal powders and metal alloys have shown positive catalytic behaviour during the com-bustion of CSPs. These are usually solid-state catalysts that play multiple roles in combustion of CSPs such as reduction in activation energy, enhancement of rate of reaction, modification of sequences in reaction-phase, influence on condensed-phase combustion and participation in combustion process in gas-phase reactions. The application of nanoscale catalysts in CSPs has increased considerably in recent past due to their superior catalytic properties as compared to their bulk-sized counterparts. A large surface-to-volume ratio and quantum size effect of nanocatalysts are considered to be plausible reasons for improving the combustion characteristics of propellants. Several efforts have been made to produce nanoscale combustion catalysts for advanced propellant formulations to improve their energetics. The work done so far is largely scattered. In this review, an effort has been made to introduce various combustion catalysts having at least a metallic entity. Recent developments of nanoscale combustion catalysts with their specific merits are discussed. The combustion chemistry of a typical CSP is briefly discussed for providing a better understanding on role of combustion catalysts in burning rate enhancement. Available information on different types of combustion nanocatalysts is also presented with critical comments.     

Finite-time tracking control and vibration suppression based on the concept of virtual control force for flexible two-link space robot

The dynamic modeling, finite-time trajectory tracking control and vibration suppression of a flexible two-link space robot are studied. Firstly, the dynamic model of the system is established by combining Lagrange method with assumed mode method. In order to ensure that the base attitude and the joints of space robot can reach the desired positions within a limited time, a non-singular fast terminal sliding mode (NFTSM) controller is designed, which realizes the finite-time convergence of the trajectory tracking errors. Subsequently, for the sake of suppressing the vibrations of flexible links, a hybrid tra-jectory based on the concept of the virtual control force is developed, which can reflect the flexible modes and the trajectory tracking errors simultaneously. By modifying the original control scheme, a NFTSM hybrid controller is proposed. The hybrid control scheme can not only realized attitude stabili-zation and trajectory tracking of joints in finite time, but also provide a new method of vibration sup-pression. The simulation results verify the effectiveness of the designed hybrid control strategy.