多通道奇异频率信号的稳相合成研究

为了解决多通道奇异频率间相位差稳定的难题,理论上分析了锁相环稳相原理,提出了一种多通道奇异频率的稳相算法。该算法通过求解奇异频率间的最大公约数,联动输出频率的同时可满足稳相合成的条件。电路实物加入适当的环路阶型设计,当输出频率在S波段时,相位差稳定性≤4°,满足使用需求,同时很好地验证了该算法的可行性和灵活性。     

滚仰式导引头稳定和跟踪特性研究

文中对用于近距格斗空空导弹的滚仰导引头在弹体扰动下的稳定和跟踪特性进行了研究.根据滚仰导引头的框结构,采用坐标变换分析了弹体扰动对导引头的影响,并得到了通过滚转框架角控制实现滚仰导引头完全隔离弹体扰动的条件,建立了滚仰导引头半捷联稳定控制模型,并进行了滚仰导引头稳定和跟踪特性仿真.仿真结果表明,当存在偏航扰动时,导引头...     

电子装备通用测试体系关键技术研究

为解决电子装备自动测试系统的数量多,功能重复等问题,提出了电子装备通用测试平台,通过分析多种总线结构、测试硬件和驱动体系的核心指标与技术特征,借鉴分层思想设计通用型体系架构,以多种测试仪器为基础,利用多层次的驱动体系屏蔽混合总线差异,将测试程序与测试仪器分离,实现了只需更换测试仪器和配置对应的驱动,便可置换底层仪器,使通用测试平台具备较强的扩展能力,覆盖更多测试需求,有效降低测试系统的数量。     

基层房屋拆迁管理软件设计特色分析

受基层拆迁公司的条件限制,难以构成一个数据信息采集、处理、上报的管理软件平台。本文提出一种基于基层拆迁公司特点的软件开发解决方案。结合具体项目,阐述"分散采集,集中处理"的信息采集策略,以及"工程管理"的状态转换处理模式;阐述数据信息处理、报表生成转换等功能实现。     

利用梯度方向的Hausdorff 距离配准红外和可见光图像

基于Hausdorff距离的算法已经被广泛应用于异源图像配准,但是现有的Hausdorff距离配准算法是在整幅图像上找最相近的点对,不仅容易出现错误匹配的情况,而且计算量很大。为了减少计算冗余和消除误配情况,提高配准的准确度,提出了一种利用梯度方向的Hausdorff距离配准算法。在进行配准时,将提取到的角点集合按照每个角点的不同梯度方向角分解为8个子集合。然后计算两幅图像中同一方向区间所对应的两个子集合间的Hausdorff距离。由于只在对应的子集合内找最相近的配准点对,减少了干扰点的数目和计算的次数,提高了计算的有效性和异源图像配准的准确度。实验结果表明,利用梯度方向的Hausdorff距离算法能够较好地运用于红外图像和可见光图像的配准,并且表现出较好的准确度和稳健性。     

应用软件运行故障监测系统的设计与实现

应用软件运行过程中发生故障会给工作带来影响。本文介绍一种解决方案:通过程序设计实现应用软件运行监测、故障发现和排除。阐述程序设计原理、方法,工作流程。相对于人工维护,大大提高了维护工作效率,把故障的影响降到最低。     

Shaped beam pattern synthesis with desired nulling level and minimum sidelobe level

For the anti-interference/denoise purpose, it usually requires minimizing the sidelobe level (SLL) of a wide-beam pattern with a desired low nulling level (NL) in the nulling region. To realize such an objective, the shaped-beam pattern synthesis (SBPS) is the most commonly used approach. However, since the SBPS problem focuses on synthesizing a predetermined beam shape, the minimum SLL via this approach cannot ensure to obtain the maximum power gain. Conversely, it cannot obtain the lowest SLL with a certain power gain requirement. Based on such consideration, this paper tries to further minimize SLL of a wide-beam pattern with a desired low NL nulling region, by solving the power gain pattern synthesis (PGPS) problem. The PGPS problem selects the array excitation by directly optimizing the power gain. Hence, it has the potential to reduce SLL, when achieving the equal mainlobe power gain constraint via SBPS. An iterative algorithm which converts the primal optimization problem into convex sub-problems is proposed, resulting in an effective problem-solving scheme. Numerical simulations demonstrate the proposed algorithm can obtain about 10-dB lower SLL than the existing algorithms.     

芯片用金刚石增强金属基复合材料研究进展

随着电子设备集成化程度越来越高,对高导热封装材料的需求也越来越大,金刚石增强金属基复合材料凭借其高导热性能成为研究焦点。然而,由于金刚石颗粒与金属基体之间的不润湿特性,具有高导热性的金刚石增强金属基复合材料难以制备。文中综述了金刚石增强金属基复合材料的研究进展,包括界面改性、工艺参数优化和复合材料制备方法,并指出了金刚石增强金属基复合材料目前存在的问题和今后的研究方向。     

Achieving high-energy storage performance in 0.67Bi1-xSmxFeO3-0.33BaTiO3 lead-free relaxor ferroelectric ceramics

BiFeO₃–BaTiO₃ (BF-BT)-based lead-free ferroelectric ceramic has attracted immense interest in energy storage applications due to its great spontaneous polarization (P_max) strength. However, high remanent polarization (P_r) has become a serious obstruction for its practical application. In this work, Sm ions were doped into 0.67BiFeO₃-0.33BaTiO₃ (0.67Bi_1-xSm_xFeO₃-0.33BaTiO₃, BS_xF-BT) to tailor the structure and energy storage properties. It was found that the doping of Sm ions effectively reduced P_r by enhancing the relaxor behavior of BF-BT ceramic, which produce an enhancement in the energy storage performance. Large recoverable energy storage density W_rec of 2.8 J/cm³ with moderate energy storage efficiency η of 55.8% (200 kV/cm) were achieved in the ceramics with x = 0.1. Moreover, the energy storage capabilities exhibited good stability at temperature (20–95 °C) and frequency (0.1–50 Hz). Furthermore, the ceramic also possessed a predominant discharge speed with a discharge time less than 0.1 μs in a circuit with a load of 200 Ω. These results showed that the W_rec and η of BF-BT ceramic could be availably promoted by the doping of Sm ions, which may be helpful for the enhancement of energy storage performance of BF-BT-based ceramics.